Category Archives: Operative Neurosurgery

Update: Subtemporal approach

It is one of the surgical routes used to reach the interpeduncular fossa, offers a good access to the medial temporal region.

The subtemporal approach avoids neocortical transgression and injury to the optic radiations. 1) 2)

Indications

The subtemporal approach is historically known as the standard approach for the treatment of tumoral, vascular and inflammatory lesions of the middle cranial fossa, the tentorium, the anterior and middle tentorial incisura, the upper-third of the clivus and the petroclival region. This approach had been recognized universally for many years as the best way to treat basilar artery (BA) apex, P1 and P2 posterior cerebral artery (PCA) and superior cerebellar artery aneurysms until the introduction of the pterional approach in 1976 by Yasargil et al. 3).

Drawbacks

Access to the posteromedial temporal region needs the retraction of the temporal lobe 4) , with a risk of vein of Labbé sacrifice.

Because of the inclination of the tentorium, temporal lobe retraction increases with a more posterior location of the lesion 5).

A more posterior-oriented supratentorial-infra- occipital variation of the subtemporal approach has been described, which is performed to effectively approach and resect epileptogenic lesions in PMT regions 6) 7).

Keyhole subtemporal approaches and zygomatic arch osteotomy have been proposed in an effort to decrease the amount of temporal lobe retraction.

A keyhole and a classic subtemporal craniotomy were executed in 4 fresh-frozen silicone-injected cadaver heads. The target was defined as the area bordered by the superior cerebellar artery, the anterior clinoid process, supraclinoid internal carotid artery, and the posterior cerebral artery. Once the target was fully visualized, Ercan et al. evaluated the amount of temporal lobe retraction by measuring the distance between the base of the middle fossa and the temporal lobe. In addition, the volume of the surgical and anatomical corridors was assessed as well as the surgical maneuverability using navigation and 3D moldings. The same evaluation was conducted after a zygomatic osteotomy was added to the two approaches.

Temporal lobe retraction was the same in the two approaches evaluated while the surgical corridor and the maneuverability were all greater in the classic subtemporal approach.

The zygomatic arch osteotomy facilitates the maneuverability and the surgical volume in both approaches, but the temporal lobe retraction benefit is confined to the lateral part of the middle fossa skull base and does not result in the retraction necessary to expose the selected target 8).


With the help of an endoscope, Sun et al exposed the internal auditory canal and cerebellopontine through a translabyrinthine approach and the inferior colliculus through a keyhole subtemporal approach. This double approach can be combined to expose the internal auditory canal and cerebellopontine angle and inferior colliculus satisfactorily in the same surgical setting. This combined approach can avoid retraction of the cerebellum and reduce serious adverse events and complications 9).

As a minimally invasive approach, this can be considered an effective method for removal of vestibular schwannoma and auditory midbrain implantation in the same surgical setting, while avoiding retraction of the cerebellum and serious adverse events and complications.

see Subtemporal medial transpetrous approach.

see Subtemporal transtentorial approach.

Subtemporal Approach for AICA Aneurysm Clipping

The subtemporal approach represents a feasible approach for retrochiasmatic craniopharyngiomas when gross total resection is not mandatory. It provides rapid access to the tumor and a caudal-to-cranial visualization that promotes minimal manipulation of critical neurovascular structures, particularly the optic apparatus 10).

Subtemporal approach for distal basilar occlusion for giant aneurysm

1) , 7)

Smith KA, Spetzler RF: Supratentorial-infraoccipital approach for posteromedial temporal lobe lesions. J Neurosurg 82:940–944, 1995
2)

Tubbs RS, Oakes WJ: Relationships of the cisternal segment of the trochlear nerve. J Neurosurg 89:1015–1019, 1998
3)

Yasargil MG, Antic J, Laciga R, Jain KK, Hodosh RM, Smith RD. Microsurgical pterional approach to aneurysms of the basilar bifurcation. Surg Neurol. 1976 Aug;6(2):83-91. PubMed PMID: 951657.
4)

Olivier A: Temporal resections in the surgical treatment of epilepsy. Epilepsy Res Suppl 5:175–188, 1992
5)

Campero A, Tróccoli G, Martins C, Fernandez-Miranda JC, Yasuda A, Rhoton AL Jr: Microsurgical approaches to the medial temporal region: an anatomical study. Neurosurgery 59 (4 Suppl 2):ONS279–ONS308, 2006
6)

Russell SM, Kelly PJ: Volumetric stereotaxy and the supra- tentorial occipitosubtemporal approach in the resection of posterior hippocampus and parahippocampal gyrus lesions. Neurosurgery 50:978–988, 2002
8)

Ercan S, Scerrati A, Wu P, Zhang J, Ammirati M. Is less always better? Keyhole and standard subtemporal approaches: evaluation of temporal lobe retraction and surgical volume with and without zygomatic osteotomy in a cadaveric model. J Neurosurg. 2017 Jul;127(1):157-164. doi: 10.3171/2016.6.JNS16663. Epub 2016 Sep 16. PubMed PMID: 27636184.
9)

Sun JQ, Han DM, Li YX, Gong SS, Zan HR, Wang T. Combined endoscope-assisted translabyrinthine subtemporal keyhole approach for vestibular Schwannoma and auditory midbrain implantation: Cadaveric study. Acta Otolaryngol. 2010 Oct;130(10):1125-9. doi: 10.3109/00016481003699674. PubMed PMID: 20367538.
10)

Wong RH, De Los Reyes K, Alikhani P, Sivaknathan S, van Gompel J, van Loveren H, Agazzi S. The Subtemporal Approach to Retroinfundibular Craniopharyngiomas: A New Look at an Old Approach. Neurosurgery. 2015 Aug 18. [Epub ahead of print] PubMed PMID: 26287553.

Update: NeuroVR

CAE Healthcare NeuroVR Surgical Simulator from CAE Healthcare on Vimeo.

https://caehealthcare.com/surgical-simulation/neurovr


Simulation technology identifies neurosurgical residency applicants with differing levels of technical ability. These results provide information for studies being developed for longitudinal studies on the acquisition, development, and maintenance of psychomotor skills. Technical abilities customized training programs that maximize individual resident bimanual psychomotor training dependant on continuously updated and validated metrics from virtual reality simulation studies should be explored 1).


“Experts” display significantly more automaticity when operating on identical simulated tumors separated by a series of different tumors using the NeuroVR platform. These results support the Fitts and Posner model of motor learning and are consistent with the concept that automaticity improves after completing residency training. The potential educational application of the findings is outlined related to neurosurgical resident training 2).


Ultrasonic aspirator force application was continually assessed during resection of simulated brain tumors by neurosurgeons, residents, and medical students. The participants performed simulated resections of 18 simulated brain tumors with different visual and haptic characteristics. The raw data, namely, coordinates of the instrument tip as well as contact force values, were collected by the simulator. To provide a visual and qualitative spatial analysis of forces, the authors created a graph, called a force pyramid, representing force sum along the z-coordinate for different xy coordinates of the tool tip.

Sixteen neurosurgeons, 15 residents, and 84 medical students participated in the study. Neurosurgeon, resident and medical student groups displayed easily distinguishable 3D “force pyramid fingerprints.” Neurosurgeons had the lowest force pyramids, indicating application of the lowest forces, followed by resident and medical student groups. Handedness, ergonomics, and visual and haptic tumor characteristics resulted in distinct well-defined 3D force pyramid patterns.

Force pyramid fingerprints provide 3D spatial assessment displays of instrument force application during simulated tumor resection. Neurosurgeon force utilization and ergonomic data form a basis for understanding and modulating resident force application and improving patient safety during tumor resection 3).

1)

Winkler-Schwartz A, Bajunaid K, Mullah MA, Marwa I, Alotaibi FE, Fares J, Baggiani M, Azarnoush H, Zharni GA, Christie S, Sabbagh AJ, Werthner P, Del Maestro RF. Bimanual Psychomotor Performance in Neurosurgical Resident Applicants Assessed Using NeuroTouch, a Virtual Reality Simulator. J Surg Educ. 2016 Nov – Dec;73(6):942-953. doi: 10.1016/j.jsurg.2016.04.013. Epub 2016 Jul 7. PubMed PMID: 27395397.
2)

Bugdadi A, Sawaya R, Olwi D, Al-Zhrani G, Azarnoush H, Sabbagh AJ, Alsideiri G, Bajunaid K, Alotaibi FE, Winkler-Schwartz A, Del Maestro R. Automaticity of Force Application During Simulated Brain Tumor Resection: Testing the Fitts and Posner Model. J Surg Educ. 2017 Jul 3. pii: S1931-7204(17)30114-9. doi: 10.1016/j.jsurg.2017.06.018. [Epub ahead of print] PubMed PMID: 28684100.
3)

Azarnoush H, Siar S, Sawaya R, Zhrani GA, Winkler-Schwartz A, Alotaibi FE, Bugdadi A, Bajunaid K, Marwa I, Sabbagh AJ, Del Maestro RF. The force pyramid: a spatial analysis of force application during virtual reality brain tumor resection. J Neurosurg. 2017 Jul;127(1):171-181. doi: 10.3171/2016.7.JNS16322. Epub 2016 Sep 30. PubMed PMID: 27689458.

Update: Navigated transcranial magnetic stimulation for language mapping

In respect to language mapping with repetitive nTMS, literature reports have yielded variable results, and it is currently not routinely performed for presurgical language localization.

The expert panel recommends nTMS motor mapping in routine neurosurgical practice, as it has a sufficient level of evidence supporting its reliability. The panel recommends that nTMS language mapping be used in the framework of clinical studies to continue refinement of its protocol and increase reliability 1).

Although language mapping by repetitive navigated transcranial magnetic stimulation (rTMS) gains importance in neuropsychological research and clinical utility, neuroscientists still use different mapping protocols including different stimulation frequencies.

The stimulation frequency has to be adapted to the aim of the rTMS language investigation 2).

2015

Ille et al. performed multimodal language mapping in 35 patients with left-sided perisylvian lesions by using rTMS, fMRI, and DCS. The rTMS mappings were conducted with a picture-to-trigger interval (PTI, time between stimulus presentation and stimulation onset) of either 0 or 300 msec. The error rates (ERs; that is, the number of errors per number of stimulations) were calculated for each region of the cortical parcellation system (CPS). Subsequently, the rTMS mappings were analyzed through different error rate thresholds (ERT; that is, the ER at which a CPS region was defined as language positive in terms of rTMS), and the 2-out-of-3 rule (a stimulation site was defined as language positive in terms of rTMS if at least 2 out of 3 stimulations caused an error). As a second step, the authors combined the results of fMRI and rTMS in a predefined protocol of combined noninvasive mapping. To validate this noninvasive protocol, they correlated its results to DCS during awake surgery.

The analysis by different rTMS ERTs obtained the highest correlation regarding sensitivity and a low rate of false positives for the ERTs of 15%, 20%, 25%, and the 2-out-of-3 rule. However, when comparing the combined fMRI and rTMS results with DCS, the authors observed an overall specificity of 83%, a positive predictive value of 51%, a sensitivity of 98%, and a negative predictive value of 95%.

In comparison with fMRI, rTMS is a more sensitive but less specific tool for preoperative language mapping than DCS. Moreover, rTMS is most reliable when using ERTs of 15%, 20%, 25%, or the 2-out-of-3 rule and a PTI of 0 msec. Furthermore, the combination of fMRI and rTMS leads to a higher correlation to DCS than both techniques alone, and the presented protocols for combined noninvasive language mapping might play a supportive role in the language-mapping assessment prior to the gold-standard intraoperative DCS 3).

2013

nTMS and MEGI were performed on 12 subjects. nTMS yielded 21 positive language disruption sites (11 speech arrest, 5 anomia, and 5 other) while DCS yielded 10 positive sites (2 speech arrest, 5 anomia, and 3 other). MEGI isolated 32 sites of peak activation with language tasks. Positive language sites were most commonly found in the pars opercularis for all three modalities. In 9 instances the positive DCS site corresponded to a positive nTMS site, while in 1 instance it did not. In 4 instances, a positive nTMS site corresponded to a negative DCS site, while 169 instances of negative nTMS and DCS were recorded. The sensitivity of nTMS was therefore 90%, specificity was 98%, the positive predictive value was 69% and the negative predictive value was 99% as compared with intraoperative DCS. MEGI language sites for verb generation and object naming correlated with nTMS sites in 5 subjects, and with DCS sites in 2 subjects. CONCLUSION: Maps of language function generated with nTMS correlate well with those generated by DCS. Negative nTMS mapping also correlates with negative DCS mapping. In our study, MEGI lacks the same level of correlation with intraoperative mapping; nevertheless it provides useful adjunct information in some cases. nTMS may offer a lesion-based method for noninvasively interrogating language pathways and be valuable in managing patients with peri-eloquent lesions 4).


Twenty patients with tumors in or close to left-sided language eloquent regions were examined by repetitive nTMS before surgery. During awake surgery, language-eloquent cortex was identified by DCS. nTMS results were compared for accuracy and reliability with regard to DCS by projecting both results into the cortical parcellation system.

Presurgical nTMS maps showed an overall sensitivity of 90.2%, specificity of 23.8%, positive predictive value of 35.6%, and negative predictive value of 83.9% compared with DCS. For the anatomic Broca’s area, the corresponding values were a sensitivity of 100%, specificity of 13.0%, positive predictive value of 56.5%, and negative predictive value of 100%, respectively.

Good overall correlation between repetitive nTMS and DCS was observed, particularly with regard to negatively mapped regions. Noninvasive inhibition mapping with nTMS is evolving as a valuable tool for preoperative mapping of language areas. Yet its low specificity in posterior language areas in the current study necessitates further research to refine the methodology 5).

1)

Krieg SM, Lioumis P, Mäkelä JP, Wilenius J, Karhu J, Hannula H, Savolainen P, Lucas CW, Seidel K, Laakso A, Islam M, Vaalto S, Lehtinen H, Vitikainen AM, Tarapore PE, Picht T. Protocol for motor and language mapping by navigated TMS in patients and healthy volunteers; workshop report. Acta Neurochir (Wien). 2017 Jul;159(7):1187-1195. doi: 10.1007/s00701-017-3187-z. Epub 2017 Apr 29. Review. PubMed PMID: 28456870.
2)

Hauck T, Tanigawa N, Probst M, Wohlschlaeger A, Ille S, Sollmann N, Maurer S, Zimmer C, Ringel F, Meyer B, Krieg SM. Stimulation frequency determines the distribution of language positive cortical regions during navigated transcranial magnetic brain stimulation. BMC Neurosci. 2015 Feb 18;16(1):5. PubMed PMID: 25880838.
3)

Ille S, Sollmann N, Hauck T, Maurer S, Tanigawa N, Obermueller T, Negwer C, Droese D, Zimmer C, Meyer B, Ringel F, Krieg SM. Combined noninvasive language mapping by navigated transcranial magnetic stimulation and functional MRI and its comparison with direct cortical stimulation. J Neurosurg. 2015 Jul;123(1):212-25. doi: 10.3171/2014.9.JNS14929. Epub 2015 Mar 6. PubMed PMID: 25748306.
4)

Tarapore PE, Findlay AM, Honma SM, Mizuiri D, Houde JF, Berger MS, Nagarajan SS. Language mapping with navigated repetitive TMS: proof of technique and validation. Neuroimage. 2013 Nov 15;82:260-72. doi: 10.1016/j.neuroimage.2013.05.018. Epub 2013 May 20. PubMed PMID: 23702420; PubMed Central PMCID: PMC3759608.
5)

Picht T, Krieg SM, Sollmann N, Rösler J, Niraula B, Neuvonen T, Savolainen P, Lioumis P, Mäkelä JP, Deletis V, Meyer B, Vajkoczy P, Ringel F. A comparison of language mapping by preoperative navigated transcranial magnetic stimulation and direct cortical stimulation during awake surgery. Neurosurgery. 2013 May;72(5):808-19. doi: 10.1227/NEU.0b013e3182889e01. PubMed PMID: 23385773.

Update: Colloid cyst endoscopy

Neuroendoscopy, has been recognised as a viable and safe alternative to microsurgery for the treatment of third ventricle colloid cyst.

Controversy remains as to which is superior 1).

Powell et al. are credited with the first successful endoscopic aspiration of the colloid cysts. 2)

Less invasive endoscopic techniques have employed rigid endoscopes with single or dual working channels.

The increased range of viewing angles of the endoscope within the cylinder of access maintained by the tubular retractor facilitates resection of the cyst through a smaller opening 3).

Entry point and trajectory

An optimal entry point and trajectory for endoscopic colloid cyst (ECC) resection helps to protect important neurovascular structures. There is a large discrepancy in the entry point and trajectory in the neuroendoscopic literature.

The endoscopic approach to colloid cysts of the third ventricle is usually performed through the foramen of Monro. However, this route does not provide adequate visualization of the cyst attachment on the tela choroidea. The combined endoscopic transforaminal-transchoroidal approach (ETTA), providing exposure of the entire cyst and a better visualization of the tela choroidea, could increase the chances of achieving a complete cyst resection 4).

Using a more anterior approach, it is easier to reach the roof of the cyst and its possible adherences with the tela choroidea 5) 6).

Trajectory views from MRI or CT scans used for cranial image guidance in 39 patients who had undergone ECC resection between July 2004 and July 2010 were retrospectively evaluated. A target point of the colloid cyst was extended out to the scalp through a trajectory carefully observed in a 3D model to ensure that important anatomical structures were not violated. The relation of the entry point to the midline and coronal sutures was established. Entry point and trajectory were correlated with the ventricular size. Results The optimal entry point was situated 42.3 ± 11.7 mm away from the sagittal suture, ranging from 19.1 to 66.9 mm (median 41.4 mm) and 46.9 ± 5.7 mm anterior to the coronal suture, ranging from 36.4 to 60.5 mm (median 45.9 mm). The distance from the entry point to the target on the colloid cyst varied from 56.5 to 78.0 mm, with a mean value of 67.9 ± 4.8 mm (median 68.5 mm). Approximately 90% of the optimal entry points are located 40-60 mm in front of the coronal suture, whereas their perpendicular distance from the midline ranges from 19.1 to 66.9 mm. The location of the “ideal” entry points changes laterally from the midline as the ventricles change in size.

The results suggest that the optimal entry for ECC excision be located at 42.3 ± 11.7 mm perpendicular to the midline, and 46.9 ± 5.7 mm anterior to the coronal suture, but also that this point differs with the size of the ventricles. Intraoperative stereotactic navigation should be considered for all ECC procedures whenever it is available. The entry point should be estimated from the patient’s own preoperative imaging studies if intraoperative neuronavigation is not available. An estimated entry point of 4 cm perpendicular to the midline and 4.5 cm anterior to the coronal suture is an acceptable alternative that can be used in patients with ventriculomegaly 7).

Complications

Intraventricular extruded colloid fragments can occur after endoscopic resection, with the possible risk demonstrated as cyst hypointensity on preoperative T2-weighted images. The finding does not seem to result in any clinical morbidity, and radiographic involution is the rule. Migratory capacity, however, does exist and justifies a more frequent imaging surveillance schedule and consideration for removal 8).


A patient presented with headaches and was found to have a colloid cyst in the third ventricle and ventriculomegaly. The patient underwent endoscopic colloid cyst resection and third ventriculostomy without incidence. Prior to emergence, a blown right pupil was acutely noted, and bright red blood emanated from the ventricular drain that was routinely placed in the endoscopy tract at the conclusion of the procedure. CT angiography demonstrated active extravasation from the pre-pontine cistern into the third ventricle and subarachnoid space. Emergency DSA confirmed active extravasation from an avulsed thalamoperforator arising from the proximal right P1 posterior cerebral artery, which was immediately embolized without incident 9).

Case series

2016

27 consecutive patients with symptomatic primary and recurrent colloid cysts. All cysts were removed via a neuroendoscope through a rostral transfrontal, transforaminal approach. The endoscope was supported by an additional cannula fixed in the stereotactic frame. Both tools were inserted into one lateral ventricle through two separate burr holes using stereotactic guidance.

The median operating time was 135 minutes. All cysts were removed completely, and no mortality or permanent complications related to surgery occurred. The mean time of observation was 43.5 months (range, 3-78 months), and no clinical or radiologic recurrences were observed. One patient with a history of an infected ventriculoperitoneal shunt did not improve after cyst removal, but improved after subsequent reimplantation of the shunt. In all other cases, symptoms resolved (67%) or decreased (30%). Cognitive functions improved or remained unchanged in all 10 elective cases examined neuropsychologically before and after surgery.

The technique describe for removal of colloid cysts are safe and effective, even for recurrent cases, and they provide 100% total resection, favorable cognitive outcomes, low risk of recurrence, and low risk of morbidity. The disadvantages of this method are a longer time for surgery and the need for more complex instrumentation compared with conventional endoscopic resection 10).

2014

56 patients were reviewed. Surgeries involved an anterolateral neuroendoscopic technique. Patients were followed postoperatively for an average of 14.9 months. Patients were also interviewed regarding their preoperative symptoms, resolution of symptoms postoperatively, and their degree of satisfaction.

The median operative time was 82 minutes, and the median duration of hospital stay was 5 days. During surgery, the ventricles were explored for residual cyst wall or cyst content, and none were encountered. On immediate postoperative imaging, cyst recurrence was not noted for any patient, and only 1 patient has had evidence of recurrence on long-term follow-up. Various preoperative symptoms were described by patients; depending on the specific symptoms, 70%-100% resolution of symptoms was shown after surgery. Along with clinical follow-up, patients were interviewed regarding their perception of surgery and recovery. Of the patients contacted, 100% reported satisfaction with the surgery, and 91% noted satisfaction with their recovery. Reported complications included memory loss, infection, deep vein thrombosis, and postoperative hematoma. There were 2 perioperative deaths (3.5%) related to surgery.

Neuroendoscopic colloid cyst resection can reliably achieve complete lesion removal with short operative times. In addition, there is a high level of reported patient satisfaction. This is till 2014 the largest case series of neuroendoscopic colloid cyst resections from a single surgeon 11).


24 patients with colloid cysts of the third ventricle treated in our department between October 2001 and January 2013 using an endoscopic approach. Clinical presentation, preoperative radiological findings, endoscopic technique employed, and complications were assessed in all patients. The mean length of patient follow-up was 5.16 years. The most common symptom was headache (75%). The average size of the resected colloid cysts was 16.25 mm, the maximum diameter measured in cranial magnetic resonance imaging. Resection was transforaminal in 16 cases (66.7%), transchoroidal in 7 (29.17%), and transseptal in 1; macroscopically complete resection was achieved in 23 of 24 procedures (95.8%). Complications included three intraventricular hemorrhages, four memory deficits (two of them transient), one case of temporary potomania, two soft tissue infections, and one meningitis. There were no statistically significant differences between the route of resection and number of complications. The Glasgow Outcome Scale at 1 year after surgery was 5 in 82.6% of the patients. A transventricular endoscopic approach allows macroscopically complete resection of third ventricle colloid cysts in most cases. The option of opening the choroidal fissure (transventricular-transchoroidal approach) during the procedure can address third ventricle colloid cysts that do not emerge sufficiently through the foramen of Monro without increasing procedure-related morbidity 12).


29 patients who underwent surgery by a variation of the standard worldwide implemented endoscopic technique. Using a more anterior approach, it is easier to reach the roof of the cyst, its possible adherences with the tela choroidea, plexus, and the internal cerebral veins. The described approach has shown to be safe, quick, and very effective with a total cyst removal rate of 86.2% 13).


24 patients.Preoperative computed tomography (CT) scans revealed hydrocephalus in all the patients. Postoperative magnetic resonance imaging (MRI) was done in all cases.

Age ranged from 16 to 57 years. There were 16 male and 8 female patients. The diameter of the cyst varied from 14 to 24 mm. Operating time ranged from 90 to 156 minutes. Total resection was achieved in 21 patients. All patients with subtotal excision underwent coagulation of residual cyst wall. The follow-up period ranged from 6 to 78 months (mean, 37 months). None of the patients developed any symptoms at 26, 31, and 39 months of follow-up. Preoperative symptoms disappeared in all the patients except for memory disorders and seizures in one patient each. No residual cyst was observed on the postoperative MRIs in 21 patients. Hospital stay was 4 to 10 days (median, 6 days). No endoscopic operation was converted into an open resection.

Endoscopic excision of a colloid cyst is an effective and safe alternate method. Although the follow-up time was short, residual cyst wall remained asymptomatic without any evidence of growth after subtotal excision and coagulation of wall 14).

2013

Of 22 patients, near-total resection was obtained in 95%. In 3 cases, a very small, radiographically occult residual was left. Complete cyst wall resection was therefore obtained in 18 (82%). There were no cases of recurrence at follow-up in any patient. No patients required craniotomy or underwent re-resection. Fifteen of 16 (94%) patients with long-term clinical follow-up remained stable or improved.

High rates of complete colloid cyst resection, with low morbidity, are possible with an anterolateral endoscopic approach with dual-instrument technique. These results support the findings of other endoscopists that show how technical modifications to traditional endoscopic approaches can produce favorable results 15).


Sixteen patients (8 female) underwent attempted endoscopic removal of a colloid cyst in the absence of ventriculomegaly. Surgery was technically successful in 15 patients. The cyst was removed completely in 13 of patients. Short-term memory loss was initially present in 3 patients and completely resolved in all but 1 patient who had presented with short-term memory loss. Temporary complications occurred in 2 patients.

Normal-size ventricles are not a contraindication to endoscopic removal of third ventricular colloid cysts. Complication rates are at least comparable to those of patients with ventriculomegaly or to those undergoing open microsurgical resection 16).


Sixty-five consecutive patients and 67 procedures for endoscopic resection of colloid cysts from 1995 to 2011 were reviewed. Degree of resection was based on intraoperative assessment and postoperative magnetic resonance imaging (MRI). Recurrence rates were compared between patients with complete resection those with coagulated cyst remnants.

Data analysis was performed of 56 patients and 58 procedures, with no follow-up in 9 patients. All patients had MRI-defined complete resection. On intraoperative assessment, 9 procedures had coagulated remnants and 45 procedures had complete resection (4 data unknown). The overall recurrence rate was 6.89% (4/58), 33.3% (3/9) with cyst remnants, and 2.2% (1/45) with total resection (P = .0124). Maximum follow-up was 144 months (mean, 40.4 months). Mean follow-up was 66.0 months for cyst remnant cases, and 33.5 months for totally resected cases. There was no mortality or permanent morbidity. Transient morbidity included memory deficit (n = 2), aseptic meningitis (n = 1), and local wound infection (n = 1).

Endoscopic colloid cyst resection results in a low overall recurrence rate. Immediate postoperative MRI was insufficient for assessing degree of resection and was a poor predictor of recurrence. Ablation of cyst remnants rather than total removal is associated with a significantly higher rate of recurrence. The primary goal of endoscopic surgery should, therefore, be removal of all cyst contents and wall remnants 17).

2006

18 patients between 1996 and 2006. All patients were operated through a single burr hole at Kocher’s point using a rigid endoscope with a single working channel. The anatomical variations of the cyst and the foramen of Monro dictated the use of the transforaminal approach, the transseptal interforniceal approach or both.

There were no mortalities or significant morbidities. The operative time ranged between 90 to 240 minutes (with a mean of 133 minutes). Five patients (27.7%) developed remediable postoperative chemical meningitis successfully controlled with steroids. Postoperative transient memory disturbance was observed in 3 patients (16.7%). One patient had a postoperative CSF leak that stopped spontaneously. Aspiration of the cyst’s contents showed variable degrees of resistance to aspiration. The period of follow-up ranged between 5 months to 8 years and 3 months (mean: 4 years and 2 months). None of our patients showed radiological evidence of cyst recurrence during the follow-up period.

Through a single right pre-coronal burr hole at Kocher’s point, several endoscopic manoeuvres can be done. These include aspiration of the contents or its piecemeal removal, combined balloon squeeze and aspiration, foraminoplasty, pellucidotomy, coagulation of cyst capsule and ETV. The choice of the appropriate approach is largely dependent on the location of the cyst and the shape of the foramen of Monro. Coronal MRI may aid in preoperative evaluation of the tucked up retroforaminal growth of the cyst. We had no recurrence in our series with a follow-up reaching more than 8 years. This could be attributed to both the marsupialization and coagulation done for the remaining cyst capsule 18).

2000

Twelve patients underwent 14 endoscopic operations in attempts to treat their colloid cysts. All patients were symptomatic, with headache being the most common complaint (8 of 12 patients). Six patients in this series exhibited enlarged ventricles associated with their colloid cysts. Using rigid endoscopes of < or =3.5-mm diameter, the cysts were inspected and fenestrated. Both hard and soft cyst contents were evacuated, and then the walls of the cysts were coagulated inside and outside. External ventriculostomy tubes were usually placed. Technical obstacles to successful completion of endoscopic colloid cyst surgery are discussed.

For 11 of the 12 patients, the colloid cysts could be treated via an endoscopic approach. The mean follow-up time was 173 weeks, and the median follow-up time was 125 weeks. For the 12th patient, bilateral scarring of the foramina of Monro precluded direct surgery; therefore, a septostomy was performed and a ventriculoperitoneal shunt was placed 19).

1999

Fifteen patients with a radiological diagnosis of colloid cysts were given the option of undergoing either endoscopic surgery or craniotomy. The average tumor size was 1.43 cm. Fourteen patients underwent planned endoscopic resections, and a craniotomy was performed initially in one patient.

Entire tumor resection was achieved with the endoscope in 12 patients (86%). A craniotomy was required for two colloid cysts that could not be resected endoscopically. In total, complete radiographic resections were achieved in 14 patients (93%). There were no permanent complications, although postoperative deficits included short-term memory loss and hemiparesis, each in one patient.

Rigid endoscopy affords good optical resolution, high magnification, and excellent illumination. Total or near total resection of colloid cysts should be the goal for all patients and can be achieved using the rigid endoscope, with little morbidity, shortened operative time, reduced length of stay, and resolution of symptoms. Although long-term follow-up is needed, we think that endoscopy should be considered as a primary treatment for most patients 20).

1998

The presenting symptoms of our patients (10 men and 5 women) were intermittent headache (10 patients), nausea (3 patients), short-term memory loss (4 patients), coma (2 patients), gait disturbance (3 patients), blurred vision (2 patients), and mental status changes (3 patients). The sizes of the cysts ranged from 4 to 50 mm (median, 22.93 mm). Depending on the radiological appearance, the procedure was performed via a right (10 patients) or left (5 patients) precoronal burr hole. A rigid neuroendoscope was used. Initial stereotactic placement of the neuroendoscope was used in two patients who had moderate hydrocephalus. In the other patients, hand-guided endoscopy was performed using an articulated arm. The cysts were perforated with a needle. The opening was enlarged with microscissors. The cyst material was aspirated, and the remaining capsule was coagulated.

The average follow-up was 15.26 months (range, 1-28 mo). Total aspiration of the cysts was achieved in 12 patients, as revealed by normal postoperative magnetic resonance imaging. Control magnetic resonance imaging revealed residual cysts in three patients. One patient presented with an asymptomatic recurrence at 1 year. Resolution of the symptoms was obtained in all patients except for two of the four patients with preoperative memory deficit (improvement without complete recovery). There was no mortality or morbidity.

These results show that endoscopy is a safe and promising percutaneous technique for the treatment of colloid cysts of the third ventricle. Longer follow-up is, however, still required 21).


The surgical technique for the endoscopic evacuation of colloid cysts of the third ventricle in 13 patients is described. The authors conclude that endoscopic resection of these lesions is a useful addition to the current surgical repertoire and a viable alternative to stereotactic aspiration or open craniotomy 22).

1)

Connolly ID, Johnson E, Lamsam L, Veeravagu A, Ratliff J, Li G. Microsurgical vs. Endoscopic Excision of Colloid Cysts: An Analysis of Complications and Costs Using a Longitudinal Administrative Database. Front Neurol. 2017 Jun 9;8:259. doi: 10.3389/fneur.2017.00259. eCollection 2017. PubMed PMID: 28649225; PubMed Central PMCID: PMC5465269.
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Powell MP, Torrens MJ, Thomson JL, Horgan JG. Isodense colloid cysts of the third ventricle: a diagnostic and therapeutic problem resolved by ventriculoscopy. Neurosurgery. 1983 Sep;13(3):234-7. PubMed PMID: 6621836.
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Ajlan AM, Kalani MA, Harsh GR. Endoscopic transtubular resection of a colloid cyst. Neurosciences (Riyadh). 2014 Jan;19(1):43-6. PubMed PMID: 24419449.
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Iacoangeli M, di Somma LG, Di Rienzo A, Alvaro L, Nasi D, Scerrati M. Combined endoscopic transforaminal-transchoroidal approach for the treatment of third ventricle colloid cysts. J Neurosurg. 2014 Jun;120(6):1471-6. doi: 10.3171/2014.1.JNS131102. Epub 2014 Mar 7. PubMed PMID: 24605835.
5)

Chibbaro S, Champeaux C, Poczos P, Cardarelli M, Di Rocco F, Iaccarino C, Servadei F, Tigan L, Chaussemy D, George B, Froelich S, Kehrli P, Romano A. Anterior trans-frontal endoscopic management of colloid cyst: an effective, safe, and elegant way of treatment. Case series and technical note from a multicenter prospective study. Neurosurg Rev. 2014 Apr;37(2):235-41; discussion 241. doi: 10.1007/s10143-013-0508-4. Epub 2013 Dec 19. PubMed PMID: 24352893.
6)

Nasi D, Iaccarino C, Romano A. Anterior trans-frontal endoscopic resection of third-ventricle colloid cyst: how I do it. Acta Neurochir (Wien). 2017 Jun;159(6):1049-1052. doi: 10.1007/s00701-017-3149-5. Epub 2017 Apr 4. PubMed PMID: 28378097.
7)

Rangel-Castilla L, Chen F, Choi L, Clark JC, Nakaji P. Endoscopic approach to colloid cyst: what is the optimal entry point and trajectory? J Neurosurg. 2014 Oct;121(4):790-6. doi: 10.3171/2014.5.JNS132031. Epub 2014 Jun 13. PubMed PMID: 24926648.
8)

Abdel Latif AM, Souweidane MM. Extruded contents of colloid cysts after endoscopic removal. J Neurosurg. 2016 Sep;125(3):570-5. doi: 10.3171/2015.6.JNS142676. Epub 2016 Jan 8. PubMed PMID: 26745480.
9)

Turner RD, Chaudry I, Turk A, Spiotta A. Onyx embolization of an avulsed thalamoperforator following endoscopic colloid cyst and lamina terminalis fenestration. J Neurointerv Surg. 2014 Jul 25. pii: neurintsurg-2014-011292. doi: 10.1136/neurintsurg-2014-011292.rep. [Epub ahead of print] PubMed PMID: 25063695.
10)

Birski M, Birska J, Paczkowski D, Furtak J, Rusinek M, Rudas M, Harat M. Combination of Neuroendoscopic and Stereotactic Procedures for Total Resection of Colloid Cysts with Favorable Neurological and Cognitive Outcomes. World Neurosurg. 2016 Jan;85:205-14. doi: 10.1016/j.wneu.2015.08.080. Epub 2015 Sep 5. PubMed PMID: 26348564.
11)

Sribnick EA, Dadashev VY, Miller BA, Hawkins S, Hadjipanayis CG. Neuroendoscopic colloid cyst resection: a case cohort with follow-up and patient satisfaction. World Neurosurg. 2014 Mar-Apr;81(3-4):584-93. doi: 10.1016/j.wneu.2013.12.006. Epub 2013 Dec 22. PubMed PMID: 24368424.
12)

Ibáñez-Botella G, Domínguez M, Ros B, De Miguel L, Márquez B, Arráez MA. Endoscopic transchoroidal and transforaminal approaches for resection of third ventricular colloid cysts. Neurosurg Rev. 2014 Apr;37(2):227-34; discussion 234. doi: 10.1007/s10143-014-0529-7. Epub 2014 Feb 14. PubMed PMID: 24526368.
13)

Chibbaro S, Champeaux C, Poczos P, Cardarelli M, Di Rocco F, Iaccarino C, Servadei F, Tigan L, Chaussemy D, George B, Froelich S, Kehrli P, Romano A. Anterior trans-frontal endoscopic management of colloid cyst: an effective, safe, and elegant way of treatment. Case series and technical note from a multicenter prospective study. Neurosurg Rev. 2014 Apr;37(2):235-41; discussion 241. doi: 10.1007/s10143-013-0508-4. Epub 2013 Dec 19. PubMed PMID: 24352893.
14)

Yadav YR, Parihar V, Pande S, Namdev H. Endoscopic management of colloid cysts. J Neurol Surg A Cent Eur Neurosurg. 2014 Sep;75(5):376-80. doi: 10.1055/s-0033-1343984. Epub 2013 May 22. PubMed PMID: 23700169.
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Wilson DA, Fusco DJ, Wait SD, Nakaji P. Endoscopic resection of colloid cysts: use of a dual-instrument technique and an anterolateral approach. World Neurosurg. 2013 Nov;80(5):576-83. doi: 10.1016/j.wneu.2012.07.014. Epub 2012 Jul 28. PubMed PMID: 22850283.
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Wait SD, Gazzeri R, Wilson DA, Abla AA, Nakaji P, Teo C. Endoscopic colloid cyst resection in the absence of ventriculomegaly. Neurosurgery. 2013 Sep;73(1 Suppl Operative):ons39-46; ons46-7. doi: 10.1227/NEU.0b013e3182870980. PubMed PMID: 23334281.
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Hoffman CE, Savage NJ, Souweidane MM. The significance of cyst remnants after endoscopic colloid cyst resection: a retrospective clinical case series. Neurosurgery. 2013 Aug;73(2):233-7; discussion 237-9. doi: 10.1227/01.neu.0000430300.10338.71. PubMed PMID: 23624411.
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Zohdi A, El Kheshin S. Endoscopic approach to colloid cysts. Minim Invasive Neurosurg. 2006 Oct;49(5):263-8. PubMed PMID: 17163338.
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Rodziewicz GS, Smith MV, Hodge CJ Jr. Endoscopic colloid cyst surgery. Neurosurgery. 2000 Mar;46(3):655-60; discussion 660-2. PubMed PMID: 10719862.
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King WA, Ullman JS, Frazee JG, Post KD, Bergsneider M. Endoscopic resection of colloid cysts: surgical considerations using the rigid endoscope. Neurosurgery. 1999 May;44(5):1103-9; discussion 1109-11. PubMed PMID: 10232544.
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Decq P, Le Guerinel C, Brugières P, Djindjian M, Silva D, Kéravel Y, Melon E, Nguyen JP. Endoscopic management of colloid cysts. Neurosurgery. 1998 Jun;42(6):1288-94; discussion 1294-6. PubMed PMID: 9632187.
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Abdou MS, Cohen AR. Endoscopic treatment of colloid cysts of the third ventricle. Technical note and review of the literature. J Neurosurg. 1998 Dec;89(6):1062-8. Review. PubMed PMID: 9833841.

Controversies in Spinal and Cranial Surgery, An Issue of Neurosurgery Clinics of North America, 1e (The Clinics: Internal Medicine)

Controversies in Spinal and Cranial Surgery, An Issue of Neurosurgery Clinics of North America, 1e (The Clinics: Internal Medicine)
By Russell R. Lonser, Daniel K. Resnick MD MS

Controversies in Spinal and Cranial Surgery, An Issue of Neurosurgery Clinics of North America, 1e (The Clinics: Internal Medicine)

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This issue of Neurosurgery Clinics focuses on Controversies in Spinal and Cranial Surgery. Article topics will include:Sacro-illiac Fusion; Interspinous Spacers;Bone Morphogenetic Protein, Platelet Concentrates and Other Biologics; MIS decompression; Pipeline flow diversion in subarachnoid hemorrhage; Direct versus indirect bypass for moyamoya disease; Management of prenatally diagnosed myelomeningocele; Management of incidental aneurysm; Surgical management of incidental low-grade glioma; and more!


Product Details

  • Published on: 2017-06-28
  • Original language: English
  • Binding: Hardcover

Editorial Reviews

About the Author
Dr. Russell R. Lonser is professor and chair of the Department of Neurological Surgery at Ohio State University. His research interests include the development of drug delivery paradigms for the central nervous system pathology, as well as investigation of tumor pathogenesis and biology. His clinical and surgical interests are centered on the treatment of brain, skull base, and spinal cord tumors. He is an author on over 250 scientific and clinical publications. He received the Young Investigator Award in 2001 and Mahaley Clinical Research Award in 2013 from the Joint Section on Tumors. He is co-inventor on a patent for imaging delivery of therapeutic agents in the nervous system. He has served the Congress of Neurological Surgeons as past President, a member-at-large of the Executive Committee, scientific meeting chair, Annual Meeting chair, and treasurer. He has been actively involved in the mentoring and training of over 40 neurosurgical fellows. He is on the editorial boards for Neurosurgery, World Neurosurgery and Journal of Neurosurgery. He is an Academic Editor for PLoS One and Science Reports and is consulting editor for Neurosurgery Clinics of North America.