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Update: Chronic traumatic encephalopathy in American football players

There is tremendous media attention regarding chronic traumatic encephalopathy (CTE), primarily because of the deaths of high profile American football players who were found to have CTE upon neuropathology 1).

Physicians in clinical practice are likely to face an increasing number of retired football players seeking evaluation for chronic neurobehavioral symptoms. Guidelines for the evaluation and treatment of these patients are sparse. Clinical criteria for a diagnosis of CTE are under development. The contribution of CTE vs other neuropathologies to neurobehavioral symptoms in these players remains unclear.

Gardner et al. describe the experience in evaluating and treating a series of 14 self-referred symptomatic players. The aim is to raise awareness in the neurology community regarding the different clinical phenotypes, idiosyncratic but potentially treatable symptoms, and the spectrum of underlying neuropathologies in these players 2).

Altered Corpus Callosum White Matter Microstructure

Forty retired National Football League (NFL) players, ages 40-65, were matched by age and divided into two groups based on their age of first exposure (AFE) to tackle football: before age 12 or at age 12 or older. Participants underwent DTI on a 3 Tesla Siemens (TIM-Verio) magnet. The whole CC and five subregions were defined and seeded using deterministic tractography. Dependent measures were fractional anisotropy (FA), trace, axial diffusivity and radial diffusivity. Results showed that former NFL players in the AFE <12 group had significantly lower FA in anterior three CC regions and higher radial diffusivity in the most anterior CC region than those in the AFE ≥12 group. 3).

Prevention

Findings suggest that regulation of practice equipment could be a fair and effective way to substantially reduce subconcussive head impact in thousands of collegiate football players 4).

Case series

2017

Case series of 202 football players whose brains were donated for research. Neuropathological evaluations and retrospective telephone clinical assessments (including head trauma history) with informants were performed blinded. Online questionnaires ascertained athletic and military history.

Neuropathological diagnoses of neurodegenerative diseases, including CTE, based on defined diagnostic criteria; CTE neuropathological severity (stages I to IV or dichotomized into mild [stages I and II] and severe [stages III and IV]); informant-reported athletic history and, for players who died in 2014 or later, clinical presentation, including behavior, mood, and cognitive symptoms and dementia.

Among 202 deceased former football players (median age at death, 66 years [interquartile range, 47-76 years]), CTE was neuropathologically diagnosed in 177 players (87%; median age at death, 67 years [interquartile range, 52-77 years]; mean years of football participation, 15.1 [SD, 5.2]), including 0 of 2 pre-high school, 3 of 14 high school (21%), 48 of 53 college (91%), 9 of 14 semiprofessional (64%), 7 of 8 Canadian Football League (88%), and 110 of 111 National Football League (99%) players. Neuropathological severity of CTE was distributed across the highest level of play, with all 3 former high school players having mild pathology and the majority of former college (27 [56%]), semiprofessional (5 [56%]), and professional (101 [86%]) players having severe pathology. Among 27 participants with mild CTE pathology, 26 (96%) had behavioral or mood symptoms or both, 23 (85%) had cognitive symptoms, and 9 (33%) had signs of dementia. Among 84 participants with severe CTE pathology, 75 (89%) had behavioral or mood symptoms or both, 80 (95%) had cognitive symptoms, and 71 (85%) had signs of dementia.

In a convenience sample of deceased football players who donated their brains for research, a high proportion had neuropathological evidence of CTE, suggesting that CTE may be related to prior participation in football 5).

1)

Riley DO, Robbins CA, Cantu RC, Stern RA. Chronic traumatic encephalopathy: Contributions from the Boston University Center for the Study of Traumatic Encephalopathy. Brain Inj. 2015;29(2):154-63. doi: 10.3109/02699052.2014.965215. PubMed PMID: 25587744.
2)

Gardner RC, Possin KL, Hess CP, Huang EJ, Grinberg LT, Nolan AL, Cohn-Sheehy BI, Ghosh PM, Lanata S, Merrilees J, Kramer JH, Berger MS, Miller BL, Yaffe K, Rabinovici GD. Evaluating and treating neurobehavioral symptoms in professional American football players: Lessons from a case series. Neurol Clin Pract. 2015 Aug;5(4):285-295. PubMed PMID: 26336629.
3)

Stamm JM, Koerte IK, Muehlmann M, Pasternak O, Bourlas AP, Baugh CM, Giwerc MY, Zhu A, Coleman MJ, Fritts NG, Martin B, Chaisson C, McClean MD, Lin AP, Cantu RC, Tripodis Y, Stern R, Shenton ME. Age at First Exposure to Football is Associated with Altered Corpus Callosum White Matter Microstructure in Former Professional Football Players. J Neurotrauma. 2015 Jul 22. [Epub ahead of print] PubMed PMID: 26200068.
4)

Reynolds BB, Patrie J, Henry EJ, Goodkin HP, Broshek DK, Wintermark M, Druzgal TJ. Practice type effects on head impact in collegiate football. J Neurosurg. 2015 Aug 4:1-10. [Epub ahead of print] PubMed PMID: 26238972.
5)

Mez J, Daneshvar DH, Kiernan PT, Abdolmohammadi B, Alvarez VE, Huber BR, Alosco ML, Solomon TM, Nowinski CJ, McHale L, Cormier KA, Kubilus CA, Martin BM, Murphy L, Baugh CM, Montenigro PH, Chaisson CE, Tripodis Y, Kowall NW, Weuve J, McClean MD, Cantu RC, Goldstein LE, Katz DI, Stern RA, Stein TD, McKee AC. Clinicopathological Evaluation of Chronic Traumatic Encephalopathy in Players of American Football. JAMA. 2017 Jul 25;318(4):360-370. doi: 10.1001/jama.2017.8334. PubMed PMID: 28742910.

Update: Cervical arthroplasty

Cervical arthroplasty was developed with the goal of preserving mobility of the cervical segment in patients with cervical degenerative disc disease.

Cervical total disc replacement (TDR) has been shown in a number of prospective clinical studies to be a viable treatment alternative to anterior cervical discectomy and fusion (ACDF) for symptomatic cervical degenerative disc disease. In addition to preserving motion, evidence suggests that cervical TDR may result in a lower incidence of subsequent surgical intervention than treatment with fusion.

One reason for this trend is the observation that in clinical studies, patients with a history of cervical arthrodesis seem to have a higher incidence of adjacent segment degeneration 1) 2) 3).

Furthermore, in biomechanical investigations, most authors have reported an increase in the segmental range of motion (ROM) and the intradiscal pressure (IDP) in the levels proximal and distal to a simulated mono- or bisegmental arthrodesis 4) 5) 6) 7) 8) 9) 10) 11) 12) 13).

While anterior cervical discectomy and fusion (ACDF) has been the standard of care for 2-level disease, a randomized clinical trial (RCT) suggested similar outcomes.

There are also critical debates regarding the long-term effects of heterotopic ossification (HO) and the prevalence of adjacent-level degeneration.

Evidence

Several large-scale clinical trials demonstrate the efficacy of 1- and 2-level cervical disc arthroplasty (CDA) for degenerative disc disease (DDD) in the subaxial cervical spine, while other studies reveal that during physiological neck flexion, the C4-5 and C5-6 discs account for more motion than the C3-4 level, causing more degenerative disc disease (DDD).

The results of a observational study were in accordance with those of the published randomized controlled trials (RCTs), suggesting substantial pain reduction both after anterior cervical interbody fusion (AIF) and Cervical total disc replacement, with slightly greater benefit after arthroplasty. The analysis of atypical patients suggested that, in patients outside the spectrum of clinical trials, both surgical interventions appeared to work to a similar extent to that shown for the cohort in the matched study. Also, in the longer-term perspective, both therapies resulted in similar benefits to the patients 14).

The available evidence showed that most of the pre-selected factors had no effect on outcome after CTDR, and the range of motion (ROM) success rate, incidence of heterotopic ossification (HO) and radiographic adjacent segment degeneration (r-ASD)/adjacent segment disease (ASD), and surgery rate for ASD are acceptable. There is a lack of evidence for some factors 15).

With a significant exception of a Cochrane review, the methodological quality of systematic reviews evaluating the evidence of C-ADR versus ACDF has to be improved. 16).

Outcome

Cervical total disc replacement presented favorable functional outcomes, fewer adverse events, and fewer secondary surgical procedures. The efficacy and safety of cervical total disc replacement are superior to those of fusion. Longer-term, multicenter studies are required for a better evaluation of the long-term efficacy and safety of the two procedures.

Although cervical disc arthroplasty (CDA) at C3-4 was infrequent, the improved clinical outcomes of CDA were similar at C3-4 to that in the other subaxial levels of the cervical spine at the approximately 5-year follow-ups. In this Asian population, who had a propensity to have ossification of the posterior longitudinal ligament, there was more heterotopic ossification (HO) formation in patients who received CDA at the C3-4 level than in other subaxial levels of the cervical spine. While the type of artificial discs could have confounded the issue, future studies with more patients are required to corroborate the phenomenon 17).

Cost-effectiveness

A study is the first to report the comparative cost-effectiveness of cervical total disc replacement (cTDR) vs anterior cervical discectomy and fusion(ACDF) for 2-level degenerative disc disease at 5 years. Ament et al conclude that, because of the negative incremental cost-effective ratio (ICER), cTDR is the dominant modality 18)

Patients who underwent CTDR for single-level degenerative disease had lower readmission rates, lower reoperation rates, and reduced index and total costs than those treated with ACDF. Cervical disc arthroplasty (CDA) was effective in reducing the monthly cost of care compared with ACDF19).

Based on a modeling evaluation, CTDR was found to be more effective and less costly over a 7-year time horizon for patients with single-level symptomatic degenerative disc disease. These results are robust across a range of scenarios and perspectives and are intended to support value-based decision making 20).

The incremental cost-effectiveness ratio of CTDR compared with traditional ACDF is lower than the commonly accepted threshold of $50,000 per QALY. This remains true with varying input parameters in a robust sensitivity analysis, reaffirming the stability of the model and the sustainability of this intervention 21).

At the same time, while generating clinical results comparable to spinal fusion, TDR incurred significantly lower costs. Therefore, both from the medical and from the financial point of view, TDR is a viable choice in the treatment of DDP 22).

Results of the sensitivity analysis indicated that CDR must remain functional for at least 14 years to establish greater cost-effectiveness than ACDF. Since the current literature has yet to demonstrate with certainty the actual durability and long-term functionality of CDR, future long-term studies are required to validate the present analysis 23).


Although cervical total disc replacement (TDR) has shown equivalence or superiority to anterior cervical discectomy and fusion (ACDF), potential problems include nonphysiological motion (hypermobility), accelerated degeneration of the facet joints, particulate wear, and compromise of the mechanical integrity of the endplate during device fixation.

There is no definitive evidence that TDR has better intermediate-term results than anterior cervical discectomy and fusion (ACDF) 24).


3D motion analysis data comparing patients after ACDF and AD replacement in ten patients who underwent C5-6 ACDF and 7 who underwent C5-6 AD replacement were enrolled. Using biplanar fluoroscopy and a model-based track technique (accurate up to 0.6 mm and 0.6°), motion analysis of axial rotation and flexion-extension of the neck was performed. Three nonoperative segments (C3-4, C4-5, and C6-7) were assessed for both intervertebral rotation (coronal, sagittal, and axial planes) and facet shear (anteroposterior and mediolateral). Results There was no difference in total neck motion comparing ACDF and AD replacement for neck extension (43.3° ± 10.2° vs 44.3° ± 12.6°, p = 0.866) and rotation (36.0° ± 6.5° vs 38.2° ± 9.3°, p = 0.576). For extension, when measured as a percentage of total neck motion, there was a greater amount of rotation at the nonoperated segments in the ACDF group than in the AD group (p = 0.003). When comparing specific motion segments, greater normalized rotation was seen in the ACDF group at C3-4 (33.2% ± 4.9% vs 26.8% ± 6.6%, p = 0.036) and C6-7 (28.5% ± 6.7% vs 20.5% ± 5.5%, p = 0.009) but not at C4-5 (33.5% ± 6.4% vs 31.8% ± 4.0%, p = 0.562). For neck rotation, greater rotation was observed at the nonoperative segments in the ACDF group than in the AD group (p = 0.024), but the differences between individual segments did not reach significance (p ≥ 0.146). Increased mediolateral facet shear was seen on neck extension with ACDF versus AD replacement (p = 0.008). Comparing each segment, C3-4 (0.9 ± 0.5 mm vs 0.4 ± 0.1 mm, p = 0.039) and C4-5 (1.0 ± 0.4 mm vs 0.5 ± 0.2 mm, p = 0.022) showed increased shear while C6-7 (1.0 ± 0.4 mm vs 1.0 ± 0.5 mm, p = 0.767) did not.

This study illustrates increased motion at nonoperative segments in patients who have undergone ACDF compared with those who have undergone AD replacement. Further studies will be required to examine whether these changes contribute to adjacent-segment disease 25).

The data from a investigational device exemption (IDE) study through 48 months signify a number of clinically relevant benefits for total disc replacement (TDR) over anterior cervical discectomy and fusion (ACDF). Patients experienced improved clinical outcomes with TDR—including improvement in pain and function outcomes and superiority in overall primary endpoint success. Additionally, incidences of adjacent segment degeneration and subsequent surgeries were reduced with TDR. Perhaps future studies and also longer-term followup of this patient cohort may continue to establish 2-level cervical TDR as a superior surgical option for symptomatic degenerative disc disease 26).


Cervical artificial disc replacement (ADR) is indicated for the treatment of severe radiculopathy permitting neural decompression and maintenance of motion.

The clinical and radiographic outcomes in cervical ADR patients using the ProDisc-C device (DePuy Synthes, West Chester, PA, USA) with a 5-9 year follow-up were collected through a prospective registry, with retrospective analysis performed on 24 consecutive patients treated with cervical ADR by a single surgeon. All patients underwent single- or two-level ADR with the ProDisc-C device. Outcome measures included neck and arm pain (visual analogue scale), disability (neck disability index [NDI]), complications and secondary surgery rates. Flexion-extension cervical radiographs were performed to assess range of motion (ROM) of the device and adjacent segment disease (ASD). Average follow-up was 7.7 years. Neck and arm pain improved 60% and 79%, respectively, and NDI had an improvement of 58%. There were no episodes of device migration or subsidence. Mean ROM of the device was 6.4°. Heterotopic ossification was present in seven patients (37%). Radiographic ASD below the device developed in four patients (21%) (one single-level and three two-level ADR). No patient required secondary surgery (repeat operations at the index level or adjacent levels). Fourteen out of 19 patients (74%) were able to return to employment, with a median return to work time of 1.3 months. The ProDisc-C device for cervical ADR is a safe option for patients providing excellent clinical outcomes, satisfactory return to work rates and maintenance of segmental motion despite radiographic evidence of heterotopic ossification and ASD on long-term follow-up 27).

Types

Biomechanical analysis

Scarce references could be found and compared regarding the cervical ADR devices’ biomechanical differences that are consequently related to their different clinical results.

One fusion device (CJ cage system, WINNOVA) and three different cervical artificial discs (Prodisc-C Nova (DePuy Synthes), Discocerv (Scient’x/Alphatec), Baguera C (Spineart)) were inserted at C5-6 disc space inside the FE model and analyzed. Hybrid loading conditions, under bending moments of 1 Nm along flexion, extension, lateral bending and axial rotation with a compressive force of 50 N along the follower loading direction, were used in this study. Biomechanical behaviors such as segmental mobility, facet joint forces, and possible wear debris phenomenon inside the core were investigated.

The segmental motions as well as facet joint forces were exaggerated after ADR regardless of type of the devices. The Baguera C mimicked the intact cervical spine regarding the location of the center of rotation (COR) only during the flexion moment. It also showed a relatively wider distribution of the contact area and significantly lower contact pressure distribution on the core compared to the other two devices. A ‘lift off’ phenomenon was noted for other two devices according to the specific loading condition.

The mobile core artificial disc Baguera C can be considered biomechanically superior to other devices by demonstrating no ‘lift off’ phenomenon, and significantly lower contact pressure distribution on core 28).

Revision surgery and explantation

Between November 2008 and July 2016, 16 patients with prior implantation underwent removal of the Galileo-type disc prosthesis (Signus, Medizintechnik, Germany) due to a call back by industry. In 10 patients C-ADR was replaced with an alternative prosthesis, 6 patients received an ACDF. Duration of surgery, time to revision, surgical procedure, complication rate, neurological status, histological findings and outcome were examined in two institutions.

The C-ADR was successfully revised in all patients. Surgery was performed through the same anterior approach as the initial access. Duration of the procedure varied between 43 and 80min. Access-related complications included irritation of the recurrent nerve in one patient and mal-positioning of the C-ADR in another patient. Follow up revealed two patients with permanent mild/moderate neurologic deficits, NDI (neck disability index) ranged between 10 and 42%.

Anterior exposure of the cervical spine for explantation and revision of C-ADR performed through the initial approach has an overall complication rate of 18.75%. Replacements of the Galileo-type disc prosthesis with an alternative prosthesis or conversion to ACDF are both suitable surgical options without significant difference in outcome 29).

Case series

2017

As part of an FDA IDE trial, a single center collected prospective outcomes data on 47 patients randomized in a 1:1 ratio to ACDF or arthroplasty.

Success of both surgical interventions remained high at the 10-year interval. Both arthrodesis and arthroplasty demonstrated statistically significant improvements in neck disability index, visual analog scale neck and arm pain scores at all intervals including 7- and 10-year periods. Arthroplasty demonstrated an advantage in comparison to arthrodesis as measured by final 10-year NDI score (8 vs. 16, P = 0.0485). Patients requiring reoperation were higher in number in the arthrodesis cohort (32%) in comparison with arthroplasty (9%) (P = 0.055).

At 7 and 10 years, cervical arthroplasty compares favorably with ACDF as defined by standard outcomes scores in a highly selected population with radiculopathy 30).

2016

A total of 200 subjects underwent single-level activC® (Aesculap AG) implantation between C-3 and C-7 for the treatment of symptomatic degenerative disc disease. Clinical and radiographic assessments were performed preoperatively, intraoperatively, at discharge, and again at 6 weeks, 6 months, 1 year, 2 years, and 4 years. Radiographic evaluations were done by an independent core laboratory using a specific software for quantitative motion analysis.

Neck Disability Index (NDI) and visual analog scale (VAS) score for neck and arm pain decreased significantly from baseline to the 4-year follow-up. The mean improvement for NDI was 20, for VAS severity and frequency of neck pain 26.4 and 28, and for VAS severity and frequency of arm pain 30.7 and 35.1, respectively. The neurological situation improved for the majority of patients (86.4%); 76.1% of cases were asymptomatic. Subsequent surgical interventions were reported in 7% of the cases, including device removals in 3%. In 2.5% a subsidence greater than 3 mm was recorded; 1 of these cases also had a migration greater than 3 mm. No device displacement, expulsion, disassembly, loose or fractured device, osteolysis, or facet joint degeneration at the index level was observed. Segmental lordotic alignment changed from -2.4° preoperatively to -6.2° at 4 years, and postoperative height was maintained during the follow-up. Advanced HO (Grade III and IV) was present in 27.1% of the cases; 82.4% showed segmental mobility. A progression of radiographic adjacent-segment degeneration occurred in 28.2%, but only 4.5% required surgical treatment.

The activ C is a safe and effective device for cervical disc replacement confirming the encouraging results after cTDR. Clinical trial registration no.: NCT02492724 ( clinicaltrials.gov ) 31)


A total of 225 patients received the Mobi-C cervical total disc replacement device and 105 patients received ACDF. The Mobi-C and ACDF follow-up rates were 90.7% and 86.7%, respectively (p = 0.39), at 60 months. There was significant improvement in all outcome scores relative to baseline at all time points. The Mobi-C patients had significantly more improvement than ACDF patients in terms of Neck Disability Index score, SF-12 Physical Component Summary, and overall satisfaction with treatment at 60 months. The reoperation rate was significantly lower with Mobi-C (4%) versus ACDF (16%). There were no significant differences in the adverse event rate between groups.

Both cervical total disc replacement and ACDF significantly improved general and disease-specific measures compared with baseline. However, there was significantly greater improvement in general and disease-specific outcome measures and a lower rate of reoperation in the 2-level disc replacement patients versus ACDF control patients. Clinical trial registration no. NCT00389597 ( clinicaltrials.gov ) 32).


Twenty patients (12 females, 8 males; median age 45.6 ± 6.9 years) treated by ACDA (BryanDisc®, Medtronic, Minneapolis, USA) underwent plain functional radiography and kinematic MRI of the cervical spine at 3T before and 6 and 24 months after surgery.

A sagittal T2-weighted (T2w) 2D turbo spin echo (TSE) sequence and a 3D T2w dataset with secondary axial reconstruction were acquired. Signal intensity of all nonoperated discs was measured in regions of interest (ROI). Disc heights adjacent to the operated segment were measured. Range of motion (ROM) was evaluated and compared to plain functional radiographs. Clinical outcome was evaluated using the visual analog scale (VAS) for head, neck and radicular pain, and the neck disability index (NDI).

Mean ROM of the cervical spine on functional plain radiographs was 21.25 ± 8.19, 22.29 ± 4.82 and 26.0 ± 6.9 degrees preoperatively and at 6-month and 24-month follow-up, respectively. Mean ROM at MRI was 27.1 ± 6.78, 29.45 ± 9.51 and 31.95 ± 9.58 degrees, respectively. There was good correlation between both techniques. Follow-up examinations demonstrated no signs of progressive degenerative disc disease of adjacent levels. All patients had clinical improvement up to 24 months after surgery.

After ACDA, kinematic MRI allows evaluation of the ROM with excellent correlation to plain functional radiographs. Mid-term follow-up after ACDA is without evidence of progressive DDD of adjacent segments 33).


A prospective, multicenter, randomized, unblinded clinical trial. Patients with symptomatic degenerative disc disease were enrolled to receive 1- or 2-level treatment with either TDR as the investigational device or ACDF as the control treatment. There were 260 patients in the 1-level study (179 TDR and 81 ACDF patients) and 339 patients in the 2-level study (234 TDR and 105 ACDF patients). RESULTS At 5 years, the occurrence of subsequent surgical intervention was significantly higher among ACDF patients for 1-level (TDR, 4.5% [8/179]; ACDF, 17.3% [14/81]; p = 0.0012) and 2-level (TDR, 7.3% [17/234]; ACDF, 21.0% [22/105], p = 0.0007) treatment. The TDR group demonstrated significantly fewer index- and adjacent-level subsequent surgeries in both the 1- and 2-level cohorts.

Five-year results showed treatment with cervical TDR to result in a significantly lower rate of subsequent surgical intervention than treatment with ACDF for both 1 and 2 levels of treatment. Clinical trial registration no.: NCT00389597 ( clinicaltrials.gov ) 34).

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Chang PY, Chang HK, Wu JC, Huang WC, Fay LY, Tu TH, Wu CL, Cheng H. Differences between C3-4 and other subaxial levels of cervical disc arthroplasty: more heterotopic ossification at the 5-year follow-up. J Neurosurg Spine. 2016 May;24(5):752-9. doi: 10.3171/2015.10.SPINE141217. Epub 2016 Jan 29. PubMed PMID: 26824584.
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McDonald CP, Chang V, McDonald M, Ramo N, Bey MJ, Bartol S. Three-dimensional motion analysis of the cervical spine for comparison of anterior cervical decompression and fusion versus artificial disc replacement in 17 patients. J Neurosurg Spine. 2013 Dec 20. [Epub ahead of print] PubMed PMID: 24359000.
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Davis RJ, Nunley PD, Kim KD, Hisey MS, Jackson RJ, Bae HW, Hoffman GA, Gaede SE, Danielson GO 3rd, Gordon C, Stone MB. Two-level total disc replacement with Mobi-C cervical artificial disc versus anterior discectomy and fusion: a prospective, randomized, controlled multicenter clinical trial with 4-year follow-up results. J Neurosurg Spine. 2015 Jan;22(1):15-25. doi: 10.3171/2014.7.SPINE13953. PubMed PMID: 25380538.
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Malham GM, Parker RM, Ellis NJ, Chan PG, Varma D. Cervical artificial disc replacement with ProDisc-C: Clinical and radiographic outcomes with long-term follow-up. J Clin Neurosci. 2013 Nov 15. pii: S0967-5868(13)00607-3. doi: 10.1016/j.jocn.2013.09.013. [Epub ahead of print] PubMed PMID: 24417795.
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Update: Awake surgery

An awake craniotomy is a safe neurosurgical procedure that minimizes the risk of brain injury. During the course of this surgery, the patient is asked to perform motor or cognitive tasks, but some patients exhibit severe sleepiness.

For neurosurgery with an awake craniotomy, the critical issue is to set aside enough time to identify eloquentcortices by electrocortical stimulation (ECS). High gamma activity (HGA) ranging between 80 and 120 Hz on electrocorticogram (ECoG) is assumed to reflect localized cortical processing.

Indications

Gross total removal of glioma is limited by proximity to eloquent brain. Awake surgery allows for intraoperative monitoring to safely identify eloquent regions.


For a long time, the right hemisphere (RH) was considered as “non-dominant”, especially in right-handers. In neurosurgical practice, this dogma resulted in the selection of awake craniotomy with language mapping only for lesions of the left dominant hemisphere. Conversely, surgery under general anesthesia (possibly with motor mapping) was usually proposed for right lesions. However, when objective neuropsychological tests were performed, they frequently revealed cognitive and behavioral deficits following brain surgery, even in the RH. Therefore, to preserve an optimal quality of life, especially in patients with a long survival expectancy (as in low-grade gliomas), awake surgery with cortical and axonal electrostimulation mapping has recently been proposed for right tumors resection. Here, we review new insights gained from intraoperative stimulation into the pivotal role of the RH in movement execution and control, visual processes and spatial cognition, language and non-verbal semantic processing, executive functions (e.g. attention), and social cognition (mentalizing and emotion recognition). Such original findings, that break with the myth of a “non-dominant” RH, may have important implications in cognitive neurosciences, by improving our knowledge of the functional connectivity of the RH, as well as for the clinical management of patients with a right lesion. Indeed, in brain surgery, awake mapping should be considered more systematically in the RH. Moreover, neuropsychological examination must be achieved in a more systematic manner before and after surgery within the RH, to optimize the care by predicting the likelihood of functional recovery and by elaborating specific programs of rehabilitation 1).

Operations in eloquent areas

Awake craniotomy was introduced for surgical treatment of epilepsy, and has subsequently been used in patients with supratentorial tumors, intracranial arteriovenous malformationdeep brain stimulation, and mycotic aneurysms near critical regions of brain.

Patients are selected for awake craniotomy when the planned procedure involves eloquent areas of the brain, necessitating an awake, cooperative patient capable of undergoing neurocognitive testing, especially speech area, (Broca’s areaWernicke’s area) near motor stripthalamus, removal of brainstem tumors, some seizure surgery.

The critical issue is to set aside enough time to identify eloquent cortices by electrocortical stimulation (ECS). High gamma activity (HGA) ranging between 80 and 120 Hz on electrocorticogram (ECoG) is assumed to reflect localized cortical processing. In this report, we used realtime HGA mapping and functional magnetic resonance imaging (fMRI) for rapid and reliable identification of motor and language functions. Three patients with intra-axial tumors in their dominant hemisphere underwent preoperative fMRI and lesion resection with an awake craniotomy. All patients showed significant fMRI activation evoked by motor and language tasks. After the craniotomy, we recorded ECoG activity by placing subdural grids directly on the exposed brain surface. Each patient performed motor and language tasks and demonstrated realtime HGA dynamics in hand motor areas and parts of the inferior frontal gyrus. Sensitivity and specificity of HGA mapping were 100% compared to ECS mapping in the frontal lobe, which suggested HGA mapping precisely indicated eloquent cortices. The investigation times of HGA mapping was significantly shorter than that of ECS mapping. Specificities of the motor and language-fMRI, however, did not reach 85%. The results of HGA mapping was mostly consistent with those of ECS mapping, although fMRI tended to overestimate functional areas. This novel technique enables rapid and accurate functional mapping 2).

Awake craniotomy for glioma

Craniotomies for glioma resection under conscious sedation (CS) have been well-documented in the literature for gliomas that are in or adjacent to eloquent areas 3) 4) 5) 6) 7).

Awake surgery for glioma aims to maximize resection to optimize prognosis while minimizing the risk of postoperative deficits.

The oncological and functional results of awake glioma surgery during the learning curve are comparable to results from established centers. The use and utility of resection probability maps are well demonstrated. The return to work level is high 8).

AC with the input of the speech and language therapist (SLT) and an experienced neuro-physiotherapist (NP) is a key component in ensuring optimal functional outcomes for patients with gliomas in eloquently located areas 9).

5 aminolevulinic acid guidance during awake craniotomy

Corns et al. describe the case of a patient with recurrent left frontal GBM encroaching on Broca’s area (eloquent brain). Gross total resection of the tumour was achieved by combining two techniques, awake resection to prevent damage to eloquent brain and 5-ALA fluorescence guidance to maximise the extent of tumour resection.This technique led to gross total resection of all T1-enhancing tumour with the avoidance of neurological deficit. The authors recommend this technique in patients when awake surgery can be tolerated and gross total resection is the aim of surgery 10)

Contraindications

Uncooperative (very young or too old patient).

Confusion.

Speech deficit

Language barrier

Brain mapping

Electrocortical stimulation (ECS) is the gold standard for functional brain mapping during an awake craniotomy.

Awake craniotomy could be challenging because of unsecured airway with risks of vomitting, epileptic attacks or unstable level of consciousness. It is considered that the patient monitoring becomes more difficult when iMRI is performed because the patient’s face cannot be obsereved directly. We should remember that conscious level as well as respiration pattern may change during operation 11).

Awake craniotomy can be safely performed in a high-field (1.5 T) iMRI suite to maximize tumor resection in eloquent brain areas with an acceptable morbidity profile at 1 month 12).

The routine use of fMRI was not useful in identifying language sites as performed and, more importantly, practiced tasks failed to prevent neurological deficits following awake craniotomy procedures 13).

Management of anesthesia

The importance of minimizing pain and preparing patients thoroughly to reduce anxiety and maximize cooperation. Awake surgery is an excellent treatment modality for brain tumors with very positive perception by patients 14).

Different anesthetic combinations, including neurolept, propofol with or without opioid infusions, and asleep-awake-asleep techniques, have been reported for awake craniotomy. In all these techniques, respiratory depression has been reported as a complication.

see dexmedetomidine

Different protocols exist for anesthetic care during awake craniotomy based on monitored anesthesia care (MAC) or general anesthesia (asleep-awake-asleep technique). Nevertheless the administration of anesthetics, expectedly, is not without drawbacks, side effects and risks. A new approach for awake craniotomies emphasizes the need of adequate communication with patients 15).

Scalp block

see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4236942/#ref11

Awake surgery with intraoperative brain mapping is highly recommended for patients with diffuse low grade gliomas in language areas, to maximise the extent of resection while preserving the integrity of functional networks and thus quality of life.

The picture naming test DO 80 is the gold standard for language assessment before, during, and after surgery.

Cognitive functioning is correlated with quality of life, itself linked with return to work.

The objective was to evaluate the significance of measuring naming speed, and its correlation with the return to professional activities. Two complementary studies are reported. In the first retrospective study, eleven patients were examined post-operatively. Five patients were selected because they were not able to resume their professional activities (“no return group 1”). They were compared with a control group of six patients who are working normally after surgery (“return group 1”). The eleven patients performed a global language and neuropsychological assessment, with a post-operative median follow-up of 35 months. In a subsequent prospective study, twelve patients were examined pre-operatively and post-operatively. Six patients who were not able to return to work (“no return group 2”) were compared with a control group of six patients who were working normally after the surgery (“return group 2”). The twelve patients performed a pre and post-operative language assessment, with a median follow-up of 9 months. Our results show, for the first time, that naming speed is significantly correlated with a major criterion of quality of life: the return to professional activities. There were no differences between the two groups regarding other measures of cognition. Assessing naming times, and not only naming accuracy, is essential in the management of low-grade glioma patients, before, during, and after surgery, to preserve their quality of life by resuming their previous professional activity. Our results have fundamental implications concerning the comprehension of language processing and its relationship with cognitive functioning 16).

Cost effectiveness

Retrospective analysis of a cohort of 17 patients with perirolandic gliomas who underwent an AC with DCS were case-control matched with 23 patients with perirolandic gliomas who underwent surgery under GA with neuromonitoring (ie, motor-evoked potentials, somatosensory-evoked potentials, phase reversal). Inpatient costs, quality-adjusted life years (QALY), extent of resection, and neurological outcome were compared between the groups.

Total inpatient expense per patient was ${\$}$ 34 804 in the AC group and ${\$}$ 46 798 in the GA group ( P = .046). QALY score for the AC group was 0.97 and 0.47 for the GA group ( P = .041). The incremental cost per QALY for the AC group was ${\$}$ 82 720 less than the GA group. Postoperative Karnofsky performance status was 91.8 in the AC group and 81.3 in the GA group (P = .047). Length of hospitalization was 4.12 days in the AC group and 7.61 days in the GA group ( P = .049).

The total inpatient costs for awake craniotomies were lower than surgery under GA. This study suggests better cost effectiveness and neurological outcome with awake craniotomies for perirolandic gliomas 17).

Case series

2017

Motomura et al. retrospectively reviewed the records of 33 consecutive patients with glial tumors in the eloquent brain areas who underwent awake surgery using iMRI. Volumetric analysis of MRI studies was performed. The pre-, intra-, and postoperative tumor volumes were measured in all cases using MRI studies obtained before, during, and after tumor resection. RESULTS Intraoperative MRI was performed to check for the presence of residual tumor during awake surgery in a total of 25 patients. Initial iMRI confirmed no further tumor resection in 9 patients (36%) because all observable tumors had already been removed. In contrast, intraoperative confirmation of residual tumor during awake surgery led to further tumor resection in 16 cases (64%) and eventually an EOR of more than 90% in 8 of 16 cases (50%). Furthermore, EOR benefiting from iMRI by more than 15% was found in 7 of 16 cases (43.8%). Interestingly, the increase in EOR as a result of iMRI for tumors associated mainly with the insular lobe was significantly greater, at 15.1%, than it was for the other tumors, which was 8.0% (p = 0.001).

This study revealed that combining awake surgery with iMRI was associated with a favorable surgical outcome for intrinsic brain tumors associated with eloquent areas. In particular, these benefits were noted for patients with tumors with complex anatomy, such as those associated with the insular lobe 18).

2016

Four illustrative cases demonstrate the efficacy of using a tablet computer platform for advanced language mapping testing with sophisticated language paradigms, and the spatial agreement between intraoperative mapping and preoperative fMRI results. The testing platform substantially improved the ability of the surgeon to detect and characterize language deficits. Use of a written word generation task to assess language production helped confirm areas of speech apraxia and speech arrest that were inadequately characterized or missed with the use of traditional paradigms, respectively. Preoperative fMRI of the analogous writing task was also assistive, displaying excellent spatial agreement with intraoperative mapping in all 4 cases. Sole use of traditional testing paradigms can be limiting during awake craniotomy procedures. Comprehensive assessment of language function will require additional use of more sophisticated and ecologically valid testing paradigms. The platform presented here provides a means to do so 19).

2015

Thirty-seven patients with brain tumor who underwent awake craniotomy were included in this study. Prior to craniotomy, the patient evaluated cognitive status, and during the surgery, each patient’s performance and attitude toward cognitive tasks were recorded by neuropsychologists.

The present findings showed that the construction and calculation abilities of the patients were moderately correlated with their sleepiness.

These results indicate that the preoperative cognitive functioning of patients was related to their sleepiness during the awake craniotomy procedure and that the patients who exhibited sleepiness during an awake craniotomy had previously experienced reduced functioning in the parietal lobe 20).

2009

From 1998 to 2007, 79 consecutive fully awake craniotomy (FAC)s for resection primary supratentorial brain tumors (PSBT) near or in eloquent brain areas (EBA), performed by a single surgeon, were prospectively followed. Two groups were defined based on time period and surgical team: group A operated on from March 1998 to July 2004 without a multidisciplinary team and group B operated on from August 2004 to October 2007 in a multidisciplinary setting. For both time periods, two groups were defined: group I had no previous history of craniotomy, while group II had undergone a previous craniotomy for a PSBT. Forty-six patients were operated on in group A, 46 in group B, 49 in group I and 30 in group II. Psychological assessment and selection were obligatory. The preferred anesthetic procedure was an intravenous high-dose opioid infusion (Fentanil 50 microg, bolus infusion until a minimum dose of 10 microg/kg). Generous scalp and periosteous infiltrations were performed. Functional cortical mapping was performed in every case. Continuous somato-sensory evoked potentials (SSEPs) and phase reversal localization were available in 48 cases. Standard microsurgical techniques were performed and monitored by continuous clinical evaluation.

Clinical data showed differences in time since clinical onset (p < 0.001), slowness of thought (p = 0.02) and memory deficits (p < 0.001) between study periods and also time since recent seizure onset for groups I and II (p = 0.001). Mean tumor volume was 51.2 +/- 48.7 cm3 and was not different among the four groups. The mean extent of tumor reduction was 90.0 +/- 12.7% and was similar for the whole series. A trend toward a larger incidence of glioblastoma multiforme occurred in group B (p = 0.05) and I (p = 0.04). Recovery of previous motor deficits was observed in 75.0% of patients, while motor worsening in 8.9% of cases. Recovery of semantic language deficits, control of refractory seizures and motor worsening were statistically more frequent in group B (p = 0.01). Satisfaction with the procedure was reported by 89.9% of patients, which was similar for all groups. Clinical complications were minimal, and surgical mortality was 1.3%.

These data suggest that FAC is safe and effective for the resection of PSBT in EBA as the main technique, and in a multidisciplinary context is associated with greater clinical and physiological monitoring. The previous history of craniotomy for PSBT did not seem to influence the outcome21).

1)

Vilasboas T, Herbet G, Duffau H. Challenging the myth of right “non-dominant” hemisphere: Lessons from cortico-subcortical stimulation mapping in awake surgery and surgical implications. World Neurosurg. 2017 Apr 15. pii: S1878-8750(17)30516-8. doi: 10.1016/j.wneu.2017.04.021. [Epub ahead of print] Review. PubMed PMID: 28419879.

2)

Kamada K, Ogawa H, Kapeller C, Prueckl R, Guger C. Rapid and low-invasive functional brain mapping by realtime visualization of high gamma activity for awake craniotomy. Conf Proc IEEE Eng Med Biol Soc. 2014 Aug;2014:6802-6805. PubMed PMID: 25571558.

3)

Bejjani GK, Nora PC, Vera PL, Broemling L, Sekhar LN. The predictive value of intraoperative somatosensory evoked potential monitoring: Review of 244 procedures. Neurosurgery 1998;43:491-8.

4)

De Benedictis A, Mortiz-Gasser S, Duffau H. Awake mapping optimizes the extent of resection for low-grade gliomas in eloquent areas. Neurosurgery 2010;66:1074-84.

5)

Peruzzi P, Bergese SD, Viloria A, Puente EG, Abdel-Rasoul M, Chiocca EA. A retrospective cohort-matched comparison of conscious sedation versus general anesthesia for supratentorial glioma resection. Clinical article. J Neurosurg 2011;114:633-9.

6)

Taylor MD, Bernstein M. Awake craniotomy with brain mapping as the routine surgical approach to treating patients with supratentorial intraaxial tumors: A prospective trial of 200 cases. J Neurosurg 1999;90:35-41.

7)

Wiedemayer H, Sandalcioglu IE, Armbruster W, Regel J, Schaefer H, Stolke D. False negative findings in intraoperative SEP monitoring: Analysis of 658 consecutive neurosurgical cases and review of published reports. J Neurol Neurosurg Psychiatry 2004;75:280-6.

8)

Mandonnet E, De Witt Hamer P, Poisson I, Whittle I, Bernat AL, Bresson D, Madadaki C, Bouazza S, Ursu R, Carpentier AF, George B, Froelich S. Initial experience using awake surgery for glioma: oncological, functional, and employment outcomes in a consecutive series of 25 cases. Neurosurgery. 2015 Apr;76(4):382-9. doi: 10.1227/NEU.0000000000000644. PubMed PMID: 25621981.

9)

Trimble G, McStravick C, Farling P, Megaw K, McKinstry S, Smyth G, Law G, Courtney H, Quigley G, Flannery T. Awake craniotomy for glioma resection: Technical aspects and initial results in a single institution. Br J Neurosurg. 2015 Jul 13:1-7. [Epub ahead of print] PubMed PMID: 26168299.

10)

Corns R, Mukherjee S, Johansen A, Sivakumar G. 5-aminolevulinic acid guidance during awake craniotomy to maximise extent of safe resection of glioblastoma multiforme. BMJ Case Rep. 2015 Jul 15;2015. pii: bcr2014208575. doi: 10.1136/bcr-2014-208575. PubMed PMID: 26177997.

11)

Kamata K, Wada K, Kinoshita M, Nomura M, Ozaki M. [A case of respiratory arrest during intraoperative magnetic resonance imaging (iMRI) for awake craniotomy]. Masui. 2014 Aug;63(8):907-10. Japanese. PubMed PMID: 25199330.

12)

Maldaun MV, Khawja SN, Levine NB, Rao G, Lang FF, Weinberg JS, Tummala S, Cowles CE, Ferson D, Nguyen AT, Sawaya R, Suki D, Prabhu SS. Awake craniotomy for gliomas in a high-field intraoperative magnetic resonance imaging suite: analysis of 42 cases. J Neurosurg. 2014 Oct;121(4):810-7. doi: 10.3171/2014.6.JNS132285.Epub 2014 Aug 8. PubMed PMID: 25105702.

13)

Trinh VT, Fahim DK, Maldaun MV, Shah K, McCutcheon IE, Rao G, Lang F, Weinberg J, Sawaya R, Suki D, Prabhu SS. Impact of Preoperative Functional Magnetic Resonance Imaging during Awake Craniotomy Procedures for Intraoperative Guidance and Complication Avoidance. Stereotact Funct Neurosurg. 2014 Sep 18;92(5):315-322. [Epub ahead of print] PubMed PMID: 25247627.

14)

Beez T, Boge K, Wager M, Whittle I, Fontaine D, Spena G, Braun S, Szelényi A, Bello L, Duffau H, Sabel M; European Low Grade Glioma Network. Tolerance of awake surgery for glioma: a prospective European Low Grade Glioma Network multicenter study. Acta Neurochir (Wien). 2013 Jul;155(7):1301-8. doi: 10.1007/s00701-013-1759-0. Epub 2013 May 21. PubMed PMID: 23689968.

15)

Hansen E, Seemann M, Zech N, Doenitz C, Luerding R, Brawanski A. Awake craniotomies without any sedation: The awake-awake-awake technique. Acta Neurochir (Wien) 2013;155:1417–24.

16)

Moritz-Gasser S, Herbet G, Maldonado IL, Duffau H. Lexical access speed is significantly correlated with the return to professional activities after awake surgery for low-grade gliomas. J Neurooncol. 2012 May;107(3):633-41. doi: 10.1007/s11060-011-0789-9. Epub 2012 Jan 24. PubMed PMID: 22270847.

17)

Eseonu CI, Rincon-Torroella J, ReFaey K, Quiñones-Hinojosa A. The Cost of Brain Surgery: Awake vs Asleep Craniotomy for Perirolandic Region Tumors. Neurosurgery. 2017 Mar 15. doi: 10.1093/neuros/nyx022. [Epub ahead of print] PubMed PMID: 28327904.

18)

Motomura K, Natsume A, Iijima K, Kuramitsu S, Fujii M, Yamamoto T, Maesawa S, Sugiura J, Wakabayashi T. Surgical benefits of combined awake craniotomy and intraoperative magnetic resonance imaging for gliomas associated with eloquent areas. J Neurosurg. 2017 Jan 6:1-8. doi: 10.3171/2016.9.JNS16152. [Epub ahead of print] PubMed PMID: 28059650.

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Morrison MA, Tam F, Garavaglia MM, Golestanirad L, Hare GM, Cusimano MD, Schweizer TA, Das S, Graham SJ. A novel tablet computer platform for advanced language mapping during awake craniotomy procedures. J Neurosurg. 2016 Apr;124(4):938-44. doi: 10.3171/2015.4.JNS15312. Epub 2015 Oct 16. PubMed PMID: 26473779.

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Itoi C, Hiromitsu K, Saito S, Yamada R, Shinoura N, Midorikawa A. Predicting sleepiness during an awake craniotomy. Clin Neurol Neurosurg. 2015 Oct 31;139:307-310. doi: 10.1016/j.clineuro.2015.10.033. [Epub ahead of print] PubMed PMID: 26571456.

21)

Pereira LC, Oliveira KM, L’Abbate GL, Sugai R, Ferreira JA, da Motta LA. Outcome of fully awake craniotomy for lesions near the eloquent cortex: analysis of a prospective surgical series of 79 supratentorial primary brain tumors with long follow-up. Acta Neurochir (Wien). 2009 Oct;151(10):1215-30. doi: 10.1007/s00701-009-0363-9. PubMed PMID: 19730779.

Update: Midline suboccipital subtonsillar approach

Marcos Tatagiba et al. described the surgical anatomy of the midline suboccipital subtonsillar approach to the hypoglossal canal. This approach includes a midline suboccipital craniotomy, dorsal opening of the foramen magnum and elevation of ipsilateral cerebellar tonsil to expose the hypoglossal nerve and its canal. The midline subtonsillar approach permits a straight primary intradural view to the hypoglossal canal. There is no necessity of condylar resections 1) 2).

It offers excellent access with a panoramic view of the cerebellomedullary cistern and its structures and therefore can be useful for a number of different pathologies in the lower petroclival region 3).


A study was performed on three alcohol (ETOH)-fixed specimens (6 sides), and the technique of the approach was highlighted. The tonsillar retraction needed to view the important structures was measured. Additionally, the records of 31 patients who underwent the STA procedure were evaluated and provide three clinical cases as examples.

Tonsillar retraction of 0.3cm (SD±0.1cm) exposed the PICA with its telo-velo-tonsillar and cortical branches. Retraction of 0.4cm (SD±0.2cm) exposed the spinal root of CN XI. Retraction of 0.9cm (SD±0.01cm) exposed the hypoglossal canal. Retraction of 1.3cm (SD±0.2cm) exposed the root exit zone of the glossopharyngeal nerve. Retraction of 1.6cm (SD±0.3cm) exposed the jugular foramen (JF), and retraction of 2.4cm (SD±0.2cm) exposed the inner auditory canal (IAC). In all of the selected cases, the pathology could be reached and exposed using the STA.

They recommend STA as a straightforward, easy-to-learn and therefore time-saving and safe procedure compared with other standard approaches to the cerebellomedullary cistern and its pathologies 4).

Indications

Glossopharyngeal neuralgia5).

Anterior, anterolateral, and posterior Foramen magnum meningioma6).

There was no significant postoperative complication in the remainder of the patientes, and their conditions improved after surgery 7).

Hypoglossal canal meningioma.

Case reports

2015

Two patients with exophytic or focal lesions in the inferior half of the medulla, who underwent surgery by suboccipital midline subtonsillar approach. This approach was not specifically described to reach MO before, and they found that the lesions produced a mild elevation of the tonsils providing a wide surgical view from the medulla to the foramen of Luchska laterally, and up to the middle cerebellar peduncle, offering a wide and safe access 8).

2010

A 36-year-old woman presented with increased intracranial pressure and cerebellar signs without hypoglossal nerve palsy. Magnetic resonance imaging showed a predominantly cystic mass with a fluid-fluid level in the foramen magnum region extending into the hypoglossal canal. The intracranial tumor was largely removed via a midline suboccipital subtonsillar approach, leaving only a tiny residue in the hypoglossal canal. Histology confirmed a schwannoma with relative hypervascularity. Twenty months later, the tumor recurred and presented as a multicystic dumbbell-shaped lesion, extending intra- and extracranially through the enlarged hypoglossal canal. A complete resection of the intracranial and intracanalicular parts of the tumor was achieved with a small extracranial remnant treated by radiosurgery. Histology revealed a focal increased K(i)67 proliferative index. In this report, we discuss the possible reasons for the absence of hypoglossal nerve palsy and the potential mechanism of the formation of the fluid-fluid level, and we consider the treatment of this lesion 9).

1)

Tatagiba M, Koerbel A, Roser F. The midline suboccipital subtonsillar approach to the hypoglossal canal: surgical anatomy and clinical application. Acta Neurochir (Wien). 2006 Sep;148(9):965-9. Epub 2006 Jul 5. Review. PubMed PMID: 16817032.
2)

Herlan S, Roser F, Ebner FH, Tatagiba M. The midline suboccipital subtonsillar approach to the cerebellomedullary cistern: how I do it. Acta Neurochir (Wien). 2017 Jul 22. doi: 10.1007/s00701-017-3270-5. [Epub ahead of print] PubMed PMID: 28735380.
3) , 4)

Herlan S, Ebner FH, Nitz A, Hirt B, Tatagiba M, Roser F. The midline suboccipital subtonsillar approach to the cerebellomedullary cistern and its structures: anatomical considerations, surgical technique and clinical application. Clin Neurol Neurosurg. 2014 Oct;125:98-105. doi: 10.1016/j.clineuro.2014.07.029. Epub 2014 Jul 27. PubMed PMID: 25113380.
5)

Roser F, Ebner FH, Schuhmann MU, Tatagiba M. Glossopharyngeal neuralgia treated with an endoscopic assisted midline suboccipital subtonsillar approach: technical note. J Neurol Surg A Cent Eur Neurosurg. 2013 Sep;74(5):318-20. doi: 10.1055/s-0032-1327447. Epub 2012 Oct 5. PubMed PMID: 23042141.
6)

Dogan M, Dogan DG. Foramen magnum meningioma: The midline suboccipital subtonsillar approach. Clin Neurol Neurosurg. 2016 Aug;147:116. doi: 10.1016/j.clineuro.2016.05.025. Epub 2016 Jun 6. PubMed PMID: 27321572.
7)

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Update: Anterior communicating artery aneurysm 

Epidemiology

The anterior communicating artery aneurysm cause aneurysmal subarachnoid hemorrhage, in about 21.0%~25.5% of spontaneous subarachnoid hemorrhage 1) 2) 3).

Saccular aneurysms are most common in the anterior communicating artery (ACoA).

Frequently it is a wide necked aneurysm with an irregular shape, incorporate parent vessels, and are associated with significant variations in vascular anatomy.


The most common site of rupture of very small intracranial aneurysms was the anterior communicating artery (ACoA). Rupture of small and very small aneurysms is unpredictable, and treatment may be considered in selected high-risk patients according to factors such as young age, ACoA location, and hypertension 4).

Classification

Anterior communicating artery aneurysms frequently present wide aneurysm necks and incorporate parent vessels. They are associated with significant variations in vascular anatomy, especially hypoplasia or aplasia of one of the proximal anterior cerebral artery.

Morphological Scoring System of Choi


Very small intracranial aneurysm (< 3 mm)

Small intracranial aneurysm (< 5 mm)

Medium sized intracranial aneurysm (5-9.9 mm)

Large or Giant intracranial aneurysm (> 10 mm)


According to 2D-DSA, the points of aneurysm are divided into 5 types 5) 6).

Chen et al., classified as Type I, II (IIa, IIb), III and IV, based on the various projections and size of aneurysm. The principle for the choice of operative side was designed based on the type of aneurysm and the A2 fork orientation (the interrelations between the plane of bilateral A2, AComA, and mid-saggital plane) 7).

Small aneurysms located at the anterior communicating artery carry significant procedural challenges due to a complex anatomy.

Inferior or downward direction

Posterior or backward direction

Etiology

In clinic, it’s very common to find out the unequal development of section A1 of anteromedial brain artery. The resulting hemodynamic changes are considered to be one of the main reasons for the formation of anterior communicating artery aneurysms 8).

Rupture risk

Vascular imaging was evaluated with 3D Slicer© to generate models of the aneurysms and surrounding vasculature. Morphological parameters were examined using univariate and multivariate analysis and included aneurysm volume, aspect ratio, size ratio, distance to bifurcation, aneurysm angle, vessel angle, flow angle, and parent-daughter angle. Multivariate logistic regression revealed that size ratio, flow angle, and parent-daughter angle were associated with aneurysm rupture after adjustment for age, sex, smoking history, and other clinical risk factors. Simple morphological parameters such as size ratio, flow angle, and parent-daughter angle may thus aid in the evaluation of rupture risk of anterior communicating artery aneurysms 9).

Clinical features

These aneurysms are usually silent until they rupture.

Suprachiasmatic pressure may cause altitudinal visual field deficits, abulia or akinetic mutism, amnestic syndromes, or hypothalamic dysfunction.

Neurologic deficits in aneurysmal rupture may reflect intraventricular hemorrhage (79%), brain hemorrhage (63%), acute hydrocephalus (25%), or frontal lobe signs (20%).

Visual symptoms

The AComA aneurysms rupture before becoming large enough to compress visual pathways, hence they present with aneurysmal subarachnoid hemorrhage rather than visual symptoms 10).

Giant AComA aneurysms are extremely rare and may present with vision loss 11).

Visual apparatus compression can occur from giant AComA aneurysm directed posteriorly and inferiorly 12).

The pattern of visual loss in these cases is variable. The common pattern of visual loss is bilateral field deficits.

The other patterns of visual loss due to AComA aneurysms are central scotoma, bilateral heteronymous deficits, monocular or binocular inferior field loss, asymmetrical bitemporal hemianopsia, and incongruous homonymous hemianopsia 13).

Diagnosis

Weisberg reviewed the CT findings in 40 patients with ruptured aneurysms of the anterior cerebral or anterior communicating arteries. Within 3 days of the ictus, the common patterns included blood in the pericallosal cistern and interhemispheric fissure, blood in the caval-septal region, unilateral or bilateral frontal hematoma, and diffuse symmetric intraventricular and basal cisternal blood 14).

For CT classification see the Modified Fisher scale.

Treatment

Endovascular coiling (EC) resulted in a more favorable clinical outcome, and microsurgical clipping (MC) resulted in more robust aneurysm repair, for unruptured ACoA aneurysms. Stent assisted coiling (SAC) had a higher treatment morbidity risk than EC, without reduction in retreatment rate. All treatments were effective in preventing SAH. The current pooled analysis of treatment outcomes provides a useful aid to pretreatment clinical decision making 15).

Endovascular treatment

Surgery

Complications

Cognitive deficits

In a retrospective follow-up study covering a time period of four years 18 patients operated upon early for an aneurysm of the anterior communicating artery (ACoA) and a control group of 21 patients with aneurysmal subarachnoid haemorrhage (SAH) from other sources than ACoA aneurysm and 9 patients with SAH of nonaneurysmal origin were subjected to neuropsychological examination. Both groups were comparable in their neurological condition on admission and in the severity of bleeding seen on CT-scan. Testing included memory functions, concentration, logical and spatial thinking, a Stroop-test, an aphasia screening test and a complex choice reaction task. Patients with SAH of a ruptured ACoA aneurysm did not differ significantly from the control group in any of the tests used. But there was a trend for the ACoA patients to have more memory problems than the patients with SAH of other origins. On the other hand the patients in the control group with aneurysmal SAH of other locations and with non-aneurysmal SAH had not significantly more problems with concentration and aphasia than the patients with ruptured ACoA aneurysm. These results, which differ from the common opinion of frequent occurrence of memory deficits in ACoA aneurysms are interpreted as a consequence of the changes in improved pre-, intra- and postoperative management in modern neurosurgery 16).

Case series

2017

Digital subtraction angiography images were reviewed for 204 patients with either a ruptured or an unruptured ACoA aneurysm. The ratio of the width of the larger A1 segment of the anterior cerebral artery to the smaller A1 segment was calculated. Patients with an A1 ratio greater than 2 were categorized as having A1 segment hypoplasia. The relationship of A1 segment hypoplasia to both patient and aneurysm characteristics was then assessed.

Of 204 patients that presented with an ACoA aneurysm, 34 (16.7%) were found to have a hypoplastic A1. Patients with A1 segment hypoplasia were less likely to have a history of smoking (44.1% vs 62.9%, p = 0.0410). ACoA aneurysms occurring in the setting of a hypoplastic A1 were also found to have a larger maximum diameter (mean 7.7 vs 6.0 mm, p = 0.0084). When considered as a continuous variable, increasing A1 ratio was associated with decreasing aneurysm dome-to-neck ratio (p = 0.0289). There was no significant difference in the prevalence of A1 segment hypoplasia between ruptured and unruptured aneurysms (18.9% vs 10.7%; p = 0.1605).

The results suggest that a hypoplastic A1 may affect the morphology of ACoA aneurysms. In addition, the relative lack of traditional risk factors for aneurysm formation in patients with A1 segment hypoplasia argues for the importance of hemodynamic factors in the formation of ACoA aneurysms in this anatomical setting 17).


Between January 2008 and May 2016, information on 179 consecutive patients with unruptured AcoA aneurysms was obtained and included demographic data, aneurysm features, risk factors for formation and rupture, treatment type, complications, and follow-up information. A 2-tailed t test was used for continuous data and the chi-square test for categorical variables. Statistical significance was set at P value < 0.05.

There were 76 patients 65 and older (42.5%) and 103 younger than 65 (57.5%). Conservative management was more common in older patients (67.1% vs 41.7%, P=0.001). Endovascular treatment was more commonly used in the older population (80% vs 61% of the treated aneurysms in older and younger group, P=0.16). Treatment-related complications were 8% but resulted in permanent neurological deficits in one patient (1.2%). Among conservatively treated aneurysms, three (3.2%) ruptured at follow-up resulting in patient death in two cases (2.4%). All three ruptures occurred in elderly patients.

With a modern approach that emphasizes endovascular therapy, especially in older individuals, unruptured AcoA aneurysms can be treated with a very low morbidity. Among patients with small aneurysms for which treatment was not deemed indicated or necessary, the rate of rupture at follow-up was not negligible, with 5.8% of older patients experiencing bleeding from the aneurysm 18).


Colby et al., retrospectively reviewed an IRB-approved database of patients with an aneurysm at a single institution for patients with ACoA or A1-A2 aneurysms treated with PED. Data analyzed included demographics, aneurysm characteristics, procedural details, follow-up results, and outcomes.

A total of 50 procedures were performed on 41 patients, including seven patients who underwent bilateral ‘H-pipe’ PED placement. The average age was 56 years and 46% of the patients were female. The average aneurysm size was 4.5 mm, and two large (>10 mm) aneurysms were treated. The vessel of origin was either the ACoA (26 aneurysms, 63%) or the A1-A2 junction (15 aneurysms, 37%). Eighteen patients (44%) had prior subarachnoid hemorrhage and 20 had previously been treated either with clipping (6 aneurysms, 15%) or coiling (14 aneurysms, 34%). Procedural success was achieved in 48/50 cases (96%) and two cases were aborted. Coils were deployed adjunctively in two cases (4%). Procedural outcomes included no deaths, one major ischemic stroke (2%), and two patients with intracranial hemorrhage (4%). Complete aneurysm occlusion was achieved in 81% of patients at 6 months and 85% of patients at last follow-up digital subtraction angiography.

The PED can be used safely and effectively in the treatment of aneurysms of the ACoA region. This represents a good alternative treatment option to microsurgical clipping and endovascular coiling 19).

2016

A prospectively maintained single-institution neuroendovascular database was accessed to identify consecutive cases of very small (<3 mm) ruptured anterior communicating artery aneurysms treated endovascularly between 2006 and 2013.

A total of 20 patients with ruptured very small (<3 mm) anterior communicating artery aneurysms were consecutively treated with coil embolization. The average maximum diameter was 2.66 ± 0.41 mm. Complete aneurysm occlusion was achieved for 17 (85%) aneurysms and near-complete aneurysm occlusion for 3 (15%) aneurysms. Intraoperative perforation was seen in 2 (10%) patients without any clinical worsening or need for an external ventricular drain. A thromboembolic event occurred in 1 (5 %) patient without clinical worsening or radiologic infarct. Median clinical follow-up was 12 (±14.1) months and median imaging follow-up was 12 (±18.4) months.

This report describes the largest series of consecutive endovascular treatments of ruptured very small anterior communicating artery aneurysms. These findings suggest that coil embolization of very small aneurysms in this location can be performed with acceptable rates of complications and recanalization 20).


Between January 2008 and February 2015, 254 consecutive patients with 255 ACoA aneurysms were treated with coiling. We retrospectively reviewed intraoperative angiograms and medical records to identify intraprocedural rupture and thrombus formation, and re-measured aneurysm morphologies using CT angiography images. Multivariate logistic regression models were used to determine independent predictors of intraprocedural rupture and thrombus formation.

Of the 231 patients included, intraprocedural rupture occurred in 10 (4.3%) patients, and thrombus formation occurred in 15 (6.5%) patients. Patients with smaller aneurysms more often experienced intraprocedural rupture than those with larger aneurysms (3.5±1.3 mm vs 5.7±2.3 mm). Multivariate analysis showed that smaller ruptured aneurysms (p=0.003) were independently associated with intraprocedural rupture. The threshold of aneurysm size separating rupture and non-rupture groups was 3.5 mm. Multivariate analysis showed that a history of hypertension (p=0.033), aneurysm neck size (p=0.004), and parent vessel angle (p=0.023) were independent predictors of thrombus formation. The threshold of parent vessel angle separating thrombus and non-thrombus groups was 60.0°.

Ruptured aneurysms <3.5 mm were associated with an increased risk of intraprocedural rupture, and parent vessel angle <60.0°, wider-neck aneurysms, and a history of hypertension were associated with increased risk of thrombus formation during coiling of ruptured ACoA aneurysms21).

2009

In 33 cases among 351 cases of ruptured anterior communicating artery aneurysms treated surgically, from 1991 to 2000, the dome of aneurysm was compressed in optic pathway. In some cases, aneurysm impacted into the optic nerve that deep hollowness was found when the aneurysm sac was removed during operation. Among 33 cases, 10 cases presented with preoperative visual symptoms, such as visual dimness (5), unilateral visual field defect (2) or unilateral visual loss (3), 20 cases had no visual symptoms. Visual symptoms could not be checked in 3 cases due to the poor mental state. In 6 cases among 20 cases having no visual symptoms, optic nerve was deeply compressed by the dome of aneurysm which was seen in the surgical field. Of 10 patients who had visual symptoms, 8 showed improvement in visual symptoms within 6 months after clipping of aneurysms. In 2 cases, the visual symptoms did not recover.

Anterior communicating artery aneurysm can cause visual symptoms by compressing the optic nerve or direct rupture to the optic nerve with focal hematoma formation. Park et al., emphasize that cerebral vascular study is highly recommended to detect intracranial aneurysm before its rupture in the case of normal CT findings with visual symptoms and frequent headache 22).

2003

A prospective study included 223 patients who were divided into three groups: Group A (83 microsurgically treated patients, 1990-1995); Group B (103 microsurgically treated patients, 1996-2000); and Group C (37 patients treated with Guglielmi Detachable Coil [GDC] embolization, 1996-2000). Depending on the direction in which the aneurysm fundus projected, the authors attempted to apply microsurgical treatment to Type 1 aneurysms (located in front of the axis formed by the pericallosal arteries). They proposed the most adapted procedure for Type 2 aneurysms (located behind the axis of the pericallosal arteries) after discussion with the neurovascular team, depending on the physiological status of the patient, the treatment risk, and the size of the aneurysm neck. In accordance with the classification of Hunt and Hess, the authors designated those patients with unruptured aneurysms (Grade 0) and some patients with ruptured aneurysms (Grades I-III) as having good preoperative grades. Patients with Grade IV or V hemorrhages were designated as having poor preoperative grades. By performing routine angiography and computerized tomography scanning, the causes of unfavorable outcome (Glasgow Outcome Scale [GOS] score < 5) and the morphological results (complete or incomplete occlusion) were analyzed. Overall, the clinical outcome was excellent (GOS Score 5) in 65% of patients, good (GOS Score 4) in 9.4%, fair (GOS Score 3) in 11.6%, poor (GOS Score 2) in 3.6%, and fatal in 10.3% (GOS Score 1). Among 166 patients in good preoperative grades, an excellent outcome was observed in 134 patients (80.7%). The combined permanent morbidity and mortality rate accounted for up to 19.3% of patients. The rates of permanent morbidity and death that were related to the initial subarachnoid hemorrhage were 6.2 and 1.5% for Group A, 6.6 and 1.3% for Group B, and 4 and 4% for Group C, respectively. The rates of permanent morbidity and death that were related to the procedure were 15.4 and 1.5% for Group A, 3.9 and 0% for Group B, and 8 and 8% for Group C, respectively. When microsurgical periods were compared, the rate of permanent morbidity or death related to microsurgical complications decreased significantly (Group A, 11 patients [16.9%] and Group B, three patients [3.9%]); Fisher exact test, p = 0.011) from the period of 1990 to 1995 to the period of 1996 to 2000. The combined rate of morbidity and mortality that was related to the endovascular procedure (16%) explained the nonsignificance of the different rates of procedural complications for the two periods, despite the significant decrease in the number of microsurgical complications. Among 57 patients in poor preoperative grade, an excellent outcome was observed in 11 patients (19.3%); however, permanent morbidity (GOS Scores 2-4) or death (GOS Score 1) occurred in 46 patients (80.7%). With regard to the correlation between vessel occlusion (the primary microsurgical complication) and the morphological characteristics of aneurysms, only the direction in which the fundus projected appeared significant as a risk factor for the microsurgically treated groups (Fisher exact test: Group A, p = 0.03; Group B, p = 0.002). The difference between endovascular and microsurgical procedures in the achievement of complete occlusion was considered significant (chi2 = 6.13, p = 0.01).

The direction in which the fundus projects was chosen as the morphological criterion between endovascular and surgical methods. The authors propose that microsurgical clip application should be the preferred option in the treatment of ACoA aneurysms with anteriorly directed fundi and that endovascular packing be selected for those lesions with posteriorly directed fundi, depending on morphological criteria 23).

Case reports

2016

Cohen et al., describe a technique for T-configured stent-assisted coiling in the management of ruptured wide-necked AcomA aneurysms by means of two simultaneous microsystems that allowed placement of two nitinol self-expandable Leo+ Baby stents (Balt Therapeutics, Montmorency, France) followed by coiling. Technical details and comparison to other dual stent configurations were presented and briefly discussed 24).


A 69-year-old male without a past history of mental disorders and neurological symptoms presented with a 2-month history of anxiety, sadness, lack of pleasure in usual activities, fatigue, difficulties falling asleep and waking up early in the morning, reduced appetite, and weight loss. The patient was diagnosed with major depressive disorder and antidepressant treatment was initiated. Subsequent non-contrast computed tomography (CT) of the head demonstrated hypointense oval-shaped lesion within the projection of the anterior communicating artery. CT angiography confirmed the diagnosis of a 0.8 × 0.6 cm saccular aneurysm originating from the anterior communicating artery and anterior cerebral artery. The patient underwent microsurgical clipping of the aneurysm. On psychiatric assessment 1 month after the surgery, there were no signs of depressive disorder and antidepressive treatment was discontinued. On follow-up visit 1 year after the surgery, the patient did not have any mood symptoms.

The case indicates that organic brain lesions, including intracranial aneurysms, should be suspected in elderly patients presenting with their first episode of mental disorder 25).

2015

Seung et al., present an unusual case of bitemporal hemianopsia caused by a large intracranial aneurysm of the ACoA. A 41-year-old woman was admitted to our neurosurgical department with a sudden-onset bursting headache and visual impairment. On admission, her vision was decreased to finger counting at 30 cm in the left eye and 50 cm in the right eye, and a severe bitemporal hemianopsia was demonstrated on visual field testing. A brain computed tomography scan revealed a subarachnoid hemorrhage at the basal cistern, and conventional cerebral catheter angiography of the left internal carotid artery demonstrated an 18×8 mm dumbbell-shaped aneurysm at the ACoA. Microscopic aneurysmal clipping was performed. An ACoA aneurysm can produce visual field defects by compressing the optic chiasm or nerves. We emphasize that it is important to diagnose an aneurysm through cerebrovascular study to prevent confusing it with pituitary apoplexy 26).


A 55-year-old man presented with a 3-year history of visual impairment associated with personality changes. His sister had died after an intracerebral aneurysmal rupture. An examination revealed poor visual acuity in the right eye with a field defect, as well as impaired neurocognition. Computed tomographic (CT) angiography (Panel A) and magnetic resonance imaging of the brain revealed a partially thrombosed, calcified, 7-cm aneurysm of the anterior communicating artery, with surrounding edema (Panel B). Thrombectomy and aneurysmal repair were performed to reduce the risk of aneurysmal rupture and to alleviate the mass effect. The patient recovered from surgery and had improvement in his neurocognitive deficits and vision, and he was able to return to work. His condition remained stable 2 years later, and delayed CT showed collapse of the aneurysmal sac (Panel C). Giant aneurysms (>2.5 cm) represent a small proportion of brain aneurysms but are associated with a high rupture rate when left untreated. Approximately 20% of patients with a brain aneurysm have a first-degree relative with a brain aneurysm 27).

1988

A study reports the case of a 42-year-old man who suffered a ruptured aneurysm of the anterior communicating artery. His memory capabilities were assessed after a considerable recovery period during which many of his memory deficits ameliorated. His scan revealed a left frontal lesion and many of his deficits were characteristic of frontal impairment. He was impaired on temporal discrimination, and he showed marked source forgetting. He also performed badly on the Brown-Peterson task, and we suggest that this is another task that may be characteristic of frontal impairment. In contrast, the patient showed normal or near normal performance on some memory tasks but not on others. It is concluded that the patient’s frontal signs are similar to those found in Korsakoff’s Syndrome, but that his memory impairment is qualitatively different from that encountered in patients with the amnesic syndrome 28).

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Chen L, Agrawal A, Kato Y, Karagiozov KL, Kumar MV, Sano H, Kanno T. Role of aneurysm projection in “A2” fork orientation for determining the side of surgical approach. Acta Neurochir (Wien). 2009 Aug;151(8):925-33; discussion 933. doi: 10.1007/s00701-009-0407-1. Epub 2009 Jun 5. PubMed PMID: 19499172.
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Update: Adenosine-induced cardiac standstill with hypotension

Several flow-arrest techniques have been introduced for the treatment of complex aneurysms that cannot be treated with conventional clipping or endovascular coil embolization. Adenosine-induced transient asystole is an alternative method of flow arrest.

Adenosine-induced flow arrest briefly reduces cerebral perfusion pressure and reduces the turgor of the aneurysm, thereby facilitating the clip ligation in complex aneurysms. Periods of flow arrest have to be carefully coordinated with the surgeon such that necessary working time is available for aneurysm dissection and clip placement. Adenosine-induced transient asystole is safe and efficacious when administered at an average of 0.3 to 0.4 mg/kg IBW in combination with remifentanil/low-dose volatile anesthetic with propofol. The adenosine dose will achieve approximately 45 seconds of controlled systemic hypotension and a bloodless surgical field. Adenosine offers the advantage of easy applicability in different situations without advanced preparation or complex logistical coordination with anesthesiology and cardiovascular surgery. This technique also allows the surgeon to have the maximum amount of space available to manipulate the aneurysm and place the clips, as no temporary clips are in the field of view. Also, temporary clips only decrease flow from the clipped inflow, whereas adenosine produces a more global hypotension and therefore often a better collapse of the aneurysm 1).

Adenosine-induced asystole for cerebral aneurysms surgery was first described by Groff et al. 2) in 1999 in posterior circulation aneurysms.

It is an easily applied technique in a variety of clinical situations. Its use requires minimal advanced preparation and no complex logistical coordination with other subspecialties. However, patient-specific dose-response relationships must be determined by exposure, so the relationship may not be known in an emergent situation. Persistent hypotension is a potentially major complication. Rapid ventricular pacing (RVP) has recently been reintroduced into cerebrovascular surgery. It is more predictable than adenosine in response time and, thus, can be used during unanticipated complications, such as aneurysmal rupture. It also induces a shorter period of hypotension compared with adenosine. However, RVP is more invasive and more complex from an anesthesia standpoint. Vascular neurosurgeons should be familiar with these techniques and know their applications and limitations 3).

Case series

2017

The aim of a study is to report the experience in the use of adenosine in aneurysm clipping and arteriovenous malformation (AVM) resection and review the literature. The records of all patients who had adenosine-assisted clipping of intracranial aneurysms and AVM resections between November 2015 and December 2016 were extracted from prospectively maintained database. The following data were collected: patient demographics, comorbidities, size and location of the aneurysms or AVM, number of boluses and total dose of adenosine administered, duration of cardiac standstill and hypotension (systolic blood pressure < 60 mmHg), intraoperative and postoperative complications and outcome scores at discharge. Literature search on Embase and PubMed for the terms “adenosine and clipping”, “adenosine and aneurysm” and “adenosine and AVM” was performed. Eight aneurysms and two AVMs were identified. While both AVMs were elective procedures, half of the aneurysm clippings were on urgent basis.

Al-Mousa et al. used adenosine safely with spontaneous return of rhythm in all cases. Temporary clips to the parent artery were applied for brief periods in 2 patients who had pre-adenosine intraoperative rupture. They did not observe any immediate or late adverse events related to administration of adenosine.

In a review, a total of ten case series and four case reports were identified. There were no reports on the use of adenosine in AVM resection. Transient adenosine-induced asystole is a safe and effective technique in facilitating surgical treatment of complex aneurysms and AVMs. In addition, adenosine use reduces the need, duration, and associated complications of temporary clip applications to parent arteries 4).

2015

A total of 22 aneurysms in 22 different patients that underwent adenosine-induced transient asystole during aneurismal neck clipping within the past 4 years were retrospectively reviewed. Adenosine was administrated intravenously in a test-incremental manner (starting with 6-12 mg and then giving additional doses as needed) in 11 patients and in an estimated manner (pre-calculated as 0.3-0.4 mg/kg) in 11 patients.

Overall, the study consisted of 18 unruptured saccular aneurysms, three ruptured saccular aneurysms, and a ruptured pseudoaneurysm. Adenosine-induced transient asystole was used in cases of temporary clipping inability, wide necked aneurysm, deep-seated aneurysm, or a thin aneurysm wall. The number of administrations, dose (mg/kg in ideal body weight) and duration of asystole were 1-4 (mean, 2.3) times, 0.08-1.27 (mean, 0.36) mg/kg and 0-30 (mean 13) seconds in the test-incremental manner and 1-2 (mean, 1.09) times, 0.24-0.42 (mean, 0.34) mg/kg and 13-41 (mean, 24) seconds in the estimated manner, respectively. There was a linear relationship between the dose and the duration of asystole. Twenty out of 22 aneurysms were clipped successfully with adenosine-induced transient asystole. However, in the other two cases, additional suction decompression was required for the final clipping. Adenosine-related cardiologic complications occurred in two cases of self-limited atrial fibrillation during restoration of the cardiac rhythm.

In our experience, adenosine-induced transient asystole was safe and helpful for satisfactory clipping of a complicated aneurysm. An estimated dose injection of adenosine was more convenient than the test-incremental method and did not result in serious cardiologic problems 5).

2009

A report describes three children, aged eight to 11 years, with high-flow cerebral arteriovenous malformations who underwent interventional neuroradiological procedures involving glue (N-butyl cyanoacrylate) embolisation under general anaesthesia. The procedure was facilitated by relative hypotension induced by esmolol infusion and intravenous adenosine boluses. To allow controlled deposition of N-butyl cyanoacrylate into the arteriovenous malformations, glue injection was synchronised with the onset of adenosine-induced brief cardiac standstill. This resulted in satisfactory obliteration of the arteriovenous malformations nidus in all cases. The haemodynamic modulations, including the adenosine-induced brief cardiac standstill, was noted to not affect the BIS values in our patients. All patients had satisfactory obliteration of their arteriovenous malformations and had good neurological outcomes at one-year follow-up 6).

1)

Britz GW. Adenosine-induced transient asystole. Methodist Debakey Cardiovasc J. 2014 Oct-Dec;10(4):220-3. doi: 10.14797/mdcj-10-4-220. Review. PubMed PMID: 25624976; PubMed Central PMCID: PMC4300060.
2)

Groff MW, Adams DC, Kahn RA, Kumbar UM, Yang BY, Bederson JB. Adenosine-induced transient asystole for management of a basilar artery aneurysm. Case report. J Neurosurg. 1999 Oct;91(4):687-90. PubMed PMID: 10507394.
3)

Rangel-Castilla L, Russin JJ, Britz GW, Spetzler RF. Update on transient cardiac standstill in cerebrovascular surgery. Neurosurg Rev. 2015 Oct;38(4):595-602. doi: 10.1007/s10143-015-0637-z. Epub 2015 May 1. PubMed PMID: 25931209.
4)

Al-Mousa A, Bose G, Hunt K, Toma AK. Adenosine-assisted neurovascular surgery: initial case series and review of literature. Neurosurg Rev. 2017 Jul 22. doi: 10.1007/s10143-017-0883-3. [Epub ahead of print] Review. PubMed PMID: 28735438.
5)

Lee SH, Kwun BD, Kim JU, Choi JH, Ahn JS, Park W, Yun JH. Adenosine-induced transient asystole during intracranial aneurysm surgery: indications, dosing, efficacy, and risks. Acta Neurochir (Wien). 2015 Nov;157(11):1879-86; discussion 1886. doi: 10.1007/s00701-015-2581-7. Epub 2015 Sep 18. PubMed PMID: 26385113.
6)

Puri GD, Sen I, Bapuraj JR. Adenosine-induced cardiac standstill to facilitate endovascular embolisation of cerebral arteriovenous malformations in children. Anaesth Intensive Care. 2009 Jul;37(4):619-23. PubMed PMID: 19681422.

Introduction to Neurosurgery for Medical Students

Introduction to Neurosurgery
for Medical Students

Guadalajara City, Mexico
Friday, August 11, 2017
1:00PM – 5:00PM

Escuela de Medicina y Ciencias de la Salud TEC de Monterrey, Campus Guadalajara
School of Medicine TEC de Monterrey Campus Guadalajara
Av. General Ramón Corona # 2514 | Zapopan | Jalisco | 45138 | México

Message from the President

Neurosurgery 101 in Mexico

In Collaboration with
Department of Neurosurgery at Saint Louis University, St Louis USA

In Collaboration with
SOCIEDAD MEXICANA DE CIRUGIA


Professor Saleem Abdulrauf

Honored Guest Speaker
Professor and Chairman
Department of Neurosurgery
Saint Louis University, Saint Louis, USA
Global President, Walter E. Dandy Neurosurgical Society


Professor Victor Navarro

Course Director
Director, School of Medicine Tec de Monterrey
Professor, Nuevo Hospital Civil de Guadalajara J.I.M.
Guadalajara, Mexico

Topics

      • Human Cortex: Functional Organization and Surgical Approaches
      • Brain Aneurysms: Decision Making and Surgery
      • Brain Vascular Malformations: Decision Making and Surgery
      • A Tour of the Skull Base
      • Open Discussion About a Career in Neurological Surgery

      • The course is FREE, but registration is required.

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