Chronic subdural hematoma recurrence
In the series of Han et al. independent risk factors for recurrence were as follows: age > 75 years (HR 1.72, 95% CI 1.03-2.88; p = 0.039), obesity (body mass index ≥ 25.0 kg/m2), and a bilateral operation 2).
Chon et al. shown that postoperative midline shifting (≥5 mm), diabetes mellitus, preoperative seizure, preoperative width of hematoma (≥20 mm), and anticoagulant therapy were independent predictors of the recurrence of chronic subdural hematoma.
According to internal architecture of hematoma, the rate of recurrence was significantly lower in the homogeneous and the trabecular type than the laminar and separated type 3).
The recurrence rate of chronic subdural hematoma cSDH seems to be related to the excessive neoangiogenesis in the parietal membrane, which is mediated via vascular endothelial growth factor (VEGF). This is found to be elevated in the hematoma fluid and is dependent on eicosanoid/prostaglandin and thromboxane synthesis via cyclooxygenase-2 (COX-2).
Jack et al.found a 12% reoperation rate. CSDH septation (seen on computed tomogram scan) was found to be an independent risk factor for recurrence requiring reoperation (p=0.04). Larger post-operative subdural haematoma volume was also significantly associated with requiring a second drainage procedure (p<0.001). Independent risk factors of larger post-operative haematoma volume included septations within a CSDH (p<0.01), increased pre-operative haematoma volume (p<0.01), and a greater amount of parenchymal atrophy (p=0.04). A simple scoring system for quantifying recurrence risk was created and validated based on patient age (< or ≥80 years), haematoma volume (< or ≥160cc), and presence of septations within the subdural collection (yes or no).
Septations within CSDHs are associated with larger post-operative residual haematoma collections requiring repeat drainage. When septations are clearly visible within a CSDH, craniotomy might be more suitable as a primary procedure as it allows greater access to a septated subdural collection. The proposed scoring system combining haematoma volume, age, and presence of septations might be useful in identifying patients at higher risk for recurrence 7).
Opening the internal hematoma membrane does not alter the rate of patients requiring revision surgery and the number of patients showing a marked residual hematoma six weeks after evacuation of a CSDH 8).
In the study of Lee et al, an extended surgical approach with partial membranectomy has no advantages regarding the rate of reoperation and the outcome. As initial treatment, burr-hole drainage with irrigation of the hematoma cavity and closed-system drainage is recommended. Extended craniotomy with membranectomy is now reserved for instances of acute rebleeding with solid hematoma 9).
Surgeons should consider informing patients with diabetes mellitus that this comorbidity is associated with an increased likelihood of recurrence
Balser et al. report 11% recurrence, which included individuals who recurred as late as 3 years after initial diagnosis 13).
Close imaging follow-up is important for CSDH patients for recurrence prediction. Using quantitative CT volumetric analysis, strong evidence was provided that changes in the residual fluid volume during the ‘self-resolution’ period can be used as significantly radiological predictors of recurrence 14).
A structural equation model showed a significant association between increased antiinflammatory activity in hematoma fluid samples and a lower risk of recurrence, but this relationship was not statistically significant in venous blood samples. Moreover, these findings indicate that anti-inflammatory activities in the hematoma may play a role in the risk of a recurrence of CSDH 15).
Irrigation with artificial cerebrospinal fluid (ACF) decreased the rate of CSDH recurrence 16).
There is no definite operative procedure for patients with intractable chronic subdural hematoma (CSDH).
Most recurrent hematomas are managed successfully with burr hole craniostomies with postoperative closed-system drainage. Refractory hematomas may be managed with a variety of techniques, including craniotomy or subdural-peritoneal shunt placement 17).
Although many studies have reported risk factors or treatments in efforts to prevent recurrence, those have focused on single recurrence, and little cumulative data is available to analyze refractory CSDH.
Matsumoto et al. defined refractory CSDH as ≥2 recurrences, then analyzed and compared clinical factors between patients with single recurrence and those with refractory CSDH in a cohort study, to clarify whether patients with refractory CSDH experience different or more risk factors than patients with single recurrence, and whether burr-hole irrigation with closed-system drainage reduces refractory CSDH.
Seventy-five patients had at least one recurrence, with single recurrence in 62 patients and ≥2 recurrences in 13 patients. In comparing clinical characteristics, patients with refractory CSDH were significantly younger (P=0.04) and showed shorter interval to first recurrence (P<0.001). Organized CSDH was also significantly associated with refractory CSDH (P=0.02). Multivariate logistic regression analysis identified first recurrence interval <1 month (OR 6.66, P<0.001) and age <71 years (OR 4.16, P<0.001) as independent risk factors for refractory CSDH. On the other hand, burr-hole irrigation with closed-system drainage did not reduce refractory CSDH.
When patients with risk factors for refractory CSDH experience recurrence, alternative surgical procedures may be considered as the second surgery, because burr-hole irrigation with closed-system drainage did not reduce refractory CSDH 18).
Subdural-peritoneal shunt 22).
Middle meningeal artery embolization
Embolization of the MMA is effective for refractory CSDH or CSDH patients with a risk of recurrence, and is considered an effective therapeutic method to stop hematoma enlargement and promote resolution 23) 24) 25) 26) 27) 28).
A pilot study indicated that perioperative middle meningeal artery (MMA) embolization could be offered as the least invasive and most effectual means of treatment for resistant patients of CSDHs with 1 or more recurrences 29).
Chihara et al. have treated three cases of CSDH with MMA embolization to date, but there was a postoperative recurrence in one patient, which required a craniotomy for hematoma removal and capsulectomy. MMA embolization blocks the blood supply from the dura to the hematoma outer membrane in order to prevent recurrences of refractory CSDH. Histopathologic examination of the outer membrane of the hematoma excised during craniotomy showed foreign-body giant cells and neovascular proliferation associated with embolization. Because part of the hematoma was organized in this case, the CSDH did not resolve when the MMA was occluded, and the development of new collateral pathways in the hematoma outer membrane probably contributed to the recurrence. Therefore, in CSDH with some organized hematoma, MMA embolization may not be effective. Magnetic resonance imaging (MRI) should be performed in these patients before embolization 30).
A retrospective analysis of 756 consecutive patients with CSDH who underwent bur hole surgery at the Hanyang University Medical Center (Seoul and Guri) between January 1, 2004, and December 31, 2014. During the 6-month follow-up, 104 patients (13.8%) with recurrence after surgery for CSDH were identified. Independent risk factors for recurrence were as follows: age > 75 years (HR 1.72, 95% CI 1.03-2.88; p = 0.039), obesity (body mass index ≥ 25.0 kg/m2), and a bilateral operation.
This study determined the risk factors for recurrence of CSDH and their effects on outcomes. Further studies are needed to account for these observations and to determine their underlying mechanisms 31).
Chronic subdural hematomas (cSDHs) have shown an increasing incidence in an ageing population over the last 20 years, while unacceptable recurrence rates of up to 30 % persist. The chronic subdural hematoma recurrence rate seems to be related to the excessive neoangiogenesis in the parietal membrane, which is mediated via vascular endothelial growth factor (VEGF). This is found to be elevated in the haematoma fluid and is dependent on eicosanoid/prostaglandin and thromboxane synthesis via cyclooxygenase-2 (COX 2). With this investigator-initiated trial (IIT) it was thought to diminish the recurrence rate of operated-on cSDHs by administering a selective COX-2 inhibitor (Celecoxib) over 4 weeks’ time postoperatively in comparison to a control group.
The thesis of risk reduction of cSDH recurrence in COX-2-inhibited patients was to be determined in a prospective, randomised, two-armed, open phase-II/III study with inclusion of 180 patients over a 2-year time period in four German university hospitals. The treated- and untreated-patient data were to be analysed by Fisher’s exact test (significance level of alpha, 0.05 [two-sided]).
After screening of 246 patients from January 2009 to April 2010, the study had to be terminated prematurely as only 23 patients (9.3 %) could be enrolled because of on-going non-steroid anti-rheumatic (NSAR) drug treatment or contraindication to Celecoxib medication. In the study population, 13 patients were treated in the control group (six women, seven men; average age 66.8 years; one adverse event (AE)/serious adverse event (SAE) needing one re-operation because of progressive cSDH (7.7 %); ten patients were treated in the treatment group (one woman, nine men; average age 64.7 years; five AEs/SAEs needing two re-operations because of one progressive cSDH and one wound infection [20 %]). Significance levels are obsolete because of insufficient patient numbers.
The theoretical advantage of COX-2 inhibition in the recurrent cSDH could not be transferred into the treatment of German cSDH patients as 66.6 % of the patients showed strict contraindications for Celecoxib. Furthermore, 55 % of the patients were already treated with some kind of COX-2 inhibition and, nevertheless, developed cSDH. Thus, although conceptually appealing, an anti-angiogenic therapy with COX-2 inhibitors for cSDH could not be realised in this patient population due to the high prevalence of comorbidities excluding the administration of COX2 inhibitors 32).
Recurrence rates after chronic subdural hematoma (CSDH) evacuation with any of actual techniques twist drill craniostomy (TDC), burr hole craniostomy, craniotomy range from 5% to 30%. Use of drain has improved recurrence rates when used with burr-hole craniostomy. Now, we analyze predictors of recurrence of TDC with drain.
Three hundred twelve consecutive patients with CSDH have been studied in a retrospective study. Operative technique in all patients consisted in TDC with drain. Data recorded included any associated comorbidity. Radiologic measures of the CSDH before and after the procedure were studied. Clinical evaluation included Modified Rankin Scale, Glasgow Coma Scale (GCS), and neurological deficits. Two groups were compared: recurrence group and nonrecurrence group. Follow-up was for at least 1 year.
Twelve percent experienced recurrence. Preoperative CSDH width, preoperative midline shift, postoperative midline width, postoperative CSDH width, and residual CSDH 1 month later were significantly associated with CSDH recurrence. The logistic regression model for the multivariate analysis revealed that postoperative midline shift and postoperative neurological deficit were significantly associated with CSDH recurrence. The duration of treatment with dexamethasone was found not to be related with recurrence. Mortality before hospital discharge was 1%. Hospital stay was 2.5 days.
TDC with drain has similar results in recurrence rates, morbidity, mortality, and outcome as other techniques as burr-hole craniostomy with drain. Preoperative and postoperative hematoma width and midline shift are independent predictors of recurrence. Brain re-expansion and time of drain maintenance are important factors related with recurrence of CSDH. Future CSDH reservoirs must avoid negative pressure and sudden pressure changes inside the whole closed drain system 33).
Mewada et al. report a case with right hemiparesis and aphasia 1 month after a fall from a bicycle. Computed tomography scan of the head showed left chronic subdural hematoma, which was evacuated by burr-hole drainage. The postoperative course was complicated by reaccumulation within short period of time. On superselective digital subtraction angiography of MMA, iatrogenic dAVF was found on left side. We embolized successfully it using n-butyl cyanoacrylate after a third irrigation. No reaccumulation found in the postoperative period or at last follow-up. They proposed a treatment protocol based on the own experience and literature review.
Refractory chronic subdural hematoma with reaccumulation within a short interval should be subjected to digital subtraction angiography of the MMA. Embolization of ipsilateral MMA is safe, effective, and a useful option for the treatment of iatrogenic dAVF and resolution of hematoma 34).
An 85-year-old male presented with left CSDH, which recurred five times. The hematoma was irrigated and drained through a left frontal burr hole during the first to third surgery and through a left parietal burr hole during the fourth and fifth surgery. The hematoma had no septation and was well-evacuated during each surgery. Antiplatelet therapy for preventing ischemic heart disease was stopped after the second surgery, the hematoma cavity was irrigated with artificial cerebrospinal fluid at the third surgery, and the direction of the drainage tube was changed to reduce the postoperative subdural air collection at the fourth surgery. However, none of these interventions was effective. He was successfully treated by fibrin glue injection into the hematoma cavity after the fifth surgery.
This procedure may be effective for refractory CSDH in elderly patients 35).
A 67-year-old man with dural arteriovenous fistula (AVF) presenting as a non-traumatic chronic subdural hematoma (CSDH). This previously healthy patient was hospitalized due to progressive headache with subacute onset. He underwent burr-hole surgery twice for evacuating the left CSDH that was thickest at the posterior temporal area. The operative procedure and finding was not extraordinary, but subdural hematoma slowly progressed for days following the revision surgery. After investigation by super-selective external carotid angiography, a dural AVF found near the transverse-sigmoid sinus was diagnosed. Dural AVF was completely occluded with trans-arterial injecting polyvinyl alchol particles into the petrosquamosal branch of the middle meningeal artery. The patient showed a good neurological outcome with no additional intervention. Brain surgeons have to consider the possibility of dural AVF and perform cerebral angiogram if necessary when they manage the cases that have a spontaneously occurred and repeatedly recurring CSDH 36).
Spontaneous intracranial hypotension (SIH) is reported to cause chronic subdural hematoma (SDH), however diagnosis of SIH in patients with SDH is not always easy.
Takahashi et al. report a case of chronic SDH refractory to repeated drainage, which was attributed to SIH. A forty-five-year-old man who had been suffering from orthostatic headache for one month was admitted to our hospital presenting with unconsciousness and hemiparesis. CT on admission revealed a chronic subdural hematoma, which was successfully treated once with subdural drainage. However, the patient fell into unconscious again with recurrence of the hematoma within several days. After two more sessions of drainage, SIH due to cerebrospinal fluid leakage was diagnosed with spinal magnetic resonance imaging (MRI) and radionuclide cisternography. Spinal MRI demonstrated abnormal fluid accumulation in the thoracic epidural space, and the radionuclide cisternogram showed early excretion of tracer into urine as well as absence of intracranial tracer filling. After treatment with epidural blood patching, the hematoma rapidly disappeared and he was discharged without symptoms. In the treatment of chronic SDH, especially in young to middle aged patient without preceding trauma or hematological disorders, physicians should pay attention to underlying SIH to avoid multiple surgery. MRI of the spine as well as radionuclide cisternography is useful in evaluation of this condition 37).
Hydrocephalus after posterior fossa decompression for Chiari type 1 deformity
Hydrocephalus may be seen in association with Chiari type 1 deformity, likely because of disruptions in normal CSF flow. Although patients sometimes demonstrate evidence of hydrocephalus during their initial presentation for CM-I, a subset of patients appear to develop hydrocephalus only after posterior fossa decompression. These patients may present with evidence of raised intracranial pressure, ventricular dilation on imaging, or persistent cerebrospinal fluid leakage postoperatively. To date, there are no reports in the literature investigating what factors are associated with the need for CSF diversion after PFD is performed to treat CM-I.
Guan et al. performed a retrospective clinical chart review of all patients who underwent PFD surgery and duraplasty for CM-I at the Primary Children’s Hospital in Utah from June 1, 2005, through May 31, 2015. Patients were dichotomized based on the need for long-term CSF diversion after PFD. Analysis included both univariate and multivariable logistic regression analyses.
The authors identified 297 decompressive surgeries over the period of the study, 22 of which required long-term postoperative CSF diversion. On multivariable analysis, age < 6 years old (OR 3.342, 95% CI 1.282-8.713), higher intraoperative blood loss (OR 1.003, 95% CI 1.001-1.006), and the presence of a fourth ventricular web (OR 3.752, 95% CI 1.306-10.783) were significantly associated with the need for long-term CSF diversion after decompressive surgery.
Younger patients, those with extensive intraoperative blood loss, and those found during surgery to have a fourth ventricular web were at higher risk for the development of CRH. Clinicians should be alert to evidence of CRH in this patient population after PFD surgery. 1) 2).
Elton et al. present three patients who developed infratentorial supracerebellar hygromas causing acute hydrocephalus after posterior cranial fossa decompression 3).
A 34-year-old woman presented with strain-related suboccipital headache and myelopathy for 6 months. Imaging revealed tonsillar herniation up to C2 level and cervical syringomyelia. A standard FMD, C1 posterior arch removal, and tonsillar reduction was performed. After an initial uneventful postoperative course, she had 2 readmissions with headache, vomiting, and ataxia. Imaging showed a tense pseudomeningocele and concomitant supratentorial and infratentorial (initially right-sided, followed by left-sided) SDHs with ventriculomegaly. She was conservatively managed with antiedema measures and had excellent relief of symptoms. For the literature review, only cases with concomitant supratentorial and infratentorial SDHs with hydrocephalus were searched online and analyzed.
Including this, 10 cases have been reported. Mean age was 25.3 years. The male-to-female ratio was 1:2.3. Symptoms appeared an average of 12.6 days postoperatively. Treatment was with conservative management in 3 cases, and 3 cases required permanent cerebrospinal fluid diversions. Mean follow-up duration was 9.4 months (range, 1-27 months).
Coexistent supratentorial and infratentorial SDHs with hydrocephalus after Chiari decompression is a very rare occurrence. Treatment needs to be individualized based on the predominant symptomatic lesion, and surgical options need to be judiciously considered. Good prognosis is the rule in most cases 4).
A 2-year-old girl with the Chiari 1 malformation underwent FMD, including suboccipital craniotomy, C1 laminectomy and durotomy without opening the arachnoid.
After initial postoperative improvement, the patient deteriorated, developing subdural hygromas and hydrocephalus. These were treated successfully with observation and acetazolamide.
Subdural hygromas may complicate FMD. A slit valve opening in the arachnoid might be part of the pathophysiology. While surgical intervention may be necessary in some circumstances, non-operative measures may be effective as well 5).
INSIGHTEC, the leader in MR-guided Focused Ultrasound (MRgFUS), has been awarded Best Medical Technology for Exablate Neuro by The Galien Foundation. Exablate Neuro is an innovative medical technology that uses focused ultrasound coupled with MR imaging (MRgFUS), to precisely target and treat areas deep within the brain through an intact skull.
The prestigious Prix Galien awards recognize excellence in scientific innovations that improve the state of human health. The Best Medical Technology award confirms INSIGHTEC’s vision of transformative healthcare and the company’s determination to improve the daily lives of patients living with essential tremor.
“It’s a great honor to receive this award, which recognizes our dedication to researching and developing a non-invasive medical treatment,” said INSIGHTEC’s CEO and Chairman of the Board, Maurice R. Ferré MD. “Our pursuit of innovation is not only driven by our founder Kobi Vortman, but also by the leading neurosurgery centers which have adopted the Exablate Neuro around the world. This is an exciting time for INSIGHTEC and spurs on our commitment to supporting healthcare professionals, deliver treatments which truly improve the lives of people worldwide.”
Having accepted the award at The American Museum of Natural History in New York City, INSIGHTEC’s Vice President of Marketing, Xen Mendelsohn Aderka added “To be seen as an innovator whilst in the presence of so many renowned figures in the pharmaceutical, biomedical and medical technology industry, is a great accolade. We thank the judges for acknowledging the hard work and dedication of our team.”
The U.S. Food and Drug Administration (FDA) approved Exablate Neuro in July 2016 for the non-invasive treatment of patients with essential tremor who had not responded to medication. Essential tremor is the most common movement disorder, affecting more than 5 million people in the United States, and millions more worldwide. Hand tremor is the most common symptom and for these patients, performing everyday tasks can seem nearly impossible and greatly impacts on their quality of life.
DIRECTOR DEL CURSO
José M. González Darder
José Hinojosa Mena-Bernal
Luis Real Peña
Javier Sendra Tello
Esteban Vega Torres
Falcotentorial meningioma treatment
The primary aim of surgical treatment for falcotentorial meningiomas is gross total excision. The vital surrounding brain structures make this a complex task.
Several surgical approaches have been described to treat falcotentorial meningiomas. These include infratentorial supracerebellar approach, suboccipital approach, occipital transtentorial approach, and combined supratentorial and infratentorial approaches 1) 2) 3).
There are two main issues in treating falcotentorial meningiomas. One is selecting the surgical approach, which includes design of the bone flap. The other main issue is whether main venous structures will be sacrificed for a radical tumor resection.
In all of the cases, Hong et al. tried to make an adequately sized bone flap, even when the tumor was quite large. Some authors have insisted on performing wide craniotomies for large falcotentorial meningiomas 4).
Quiñones-Hinojosa, et al. 5) described a bilateral occipital transtentorial/transfalcine approach for large falcotentorial meningiomas. They ligated and cut the transverse sinus after checking the patency of the occluded sinus, and used permanent aneurysmal clips to ligate the vein of Galenwhen the straight sinus was occluded. The area above and below the tentorium can provide wide exposure and reduce occipital lobe retraction during prolonged operation times. Moreover, this approach may allow surgeons some form of intraoperative flexibility in terms of their surgical plan.
Hong et al. do not suggest routine application of wide craniotomies, such as the combined supratentorial and infratentorial approach. This is because wide craniotomies may increase the total amount of bleeding, prolong the operation time, and increase the risk of cerebral cortex injury. Moreover, it is possible to completely remove huge falcotentorial meningiomas without neurological deficit via relatively small craniotomies.
A catheter for CSF drainage was inserted into the ventricle or cisternal space through the safest area in each patient. They also designed small craniotomies through which the possible access area covered the entire tumor territory. Thus, if a CSF drain is possible, then appropriately designed small craniotomies are sufficient to achieve complete tumor resection without cortex injury 6).
Every venous structure should be preserved even if they seem to lack significant function. This will help prevent complications associated with delayed lobar parenchymal hemorrhage that can be attributed to venous infarction.
In conclusion, surgical approaches should be tailored to each patient according to the origin and direction of tumor growth, feeding arteries, and the surrounding venous drainage system.
Hong et al. found that a relatively small craniotomy was sufficient to completely remove each tumor. Moreover, they found that the most important factors for avoiding surgical complications were to preserve vital deep neurovascular structures, as well as flow through the venous sinuses.
The results showed that falcotentorial meningiomas could be cured via single-stage operations without complications by applying careful perioperative planning and a delicate microsurgical technique 11).
In this operative video, the authors demonstrate an illustrative step-by-step technique for endoscopic-assisted microsurgical resection of a falcotentorial meningioma using the posterior interhemispheric retrocallosal transfalcine approach for a superiorly positioned falcotentorial meningioma. The surgical nuances are discussed, including the surgical anatomy, gravity-assisted interhemispheric approach in the lateral position, retrocallosal dissection, transfalcine exposure, tumor removal, and preservation of the vein of Galen complex. In summary, the posterior interhemispheric retrocallosal transfalcine approach is a useful surgical strategy for select superiorly positioned falcotentorial meningiomas.
From 2001 to 2005, 9 patients underwent operation for meningiomas arising from the falcotentorial junction, with some extending to and/or invading the torcula. All patients were assessed preoperatively with magnetic resonance neuroimaging and cerebral angiography. Furthermore, preoperative embolization was attempted in all cases. A supratentorial/infratentorial torcular craniotomy technique was used in all but 1 of these cases.
The average dimensions of the falcotentorial meningiomas were 5.1 x 4.4 x 4.2 cm. The angiograms revealed that these tumors were fed by branches of the internal carotid artery, choroidal arteries, branches of the meningohypophyseal trunk, and branches of the posterior cerebral artery. Preoperative embolization was achieved in only 2 patients. Five patients had gross total resection (Simpson grade 1), and 4 had subtotal resection (Simpson grade 4). Two of the tumors (22%) recurred during a mean follow-up period of 49 months (range, 17-88 months). The most common complication after surgery was cortical blindness, but all postoperative visual deficits had fully recovered at the last follow-up evaluation within several months.
An excellent outcome can be expected with detailed preoperative neuroimaging and knowledge of the nuances of the surgical technique that we describe in detail in the article 12).
Goto et al. evaluated their surgical experience over 20 years with 14 treated falcotentorial meningiomas.
In the past 20 years, 14 patients with falcotentorial junction meningiomas were surgically treated. There were seven men and seven women, whose ages ranged from 34 to 79 years. On the basis of neuroimaging studies, the authors analyzed the influence of the anatomical relationship of the tumor to the vein of Galen, patency of the vein of Galen, tumor size, and the signal intensities on the magnetic resonance images to determine possible difficulties that might be encountered during surgery and to prognosticate the outcome of surgery. Depending on the relationship with the vein of Galen, tumors were labeled as either a superior or an inferior type. All tumors were resected via an occipital transtentorial approach. The surgical outcome in eight patients was excellent; in the remaining six patients, it was fair. Of the prognostic factors, tumor location especially seemed to be the most important (p < 0.01, Fisher exact test). The outcome associated with the inferior type of tumor was significantly less optimal probably due to the relationship to the deep veins and the brainstem. In this series, the occlusion of deep veins did not significantly influence outcome.
Classification of the tumor location by preoperative neuroimaging studies can be helpful in estimating the surgical difficulty that might be encountered in treating the falcotentorial junction meningioma 13).
Meningiomas arising from the falcotentorial junction are rare. As a result, their clinical presentation and surgical management are not well described. During the past 3 years, the authors have treated six patients with falcotentorial meningiomas.
Most patients presented with symptoms related to raised intracranial pressure, including headaches, papilledema, and visual and gait disturbances. Magnetic resonance imaging revealed a smooth, oval, or round mass, which was typically homogeneously enhancing. Angiography was useful in evaluating arterial supply for embolization, when possible, and determining the status of venous collateral supply and sinus patency. The authors detail the surgical technique used in all six patients. Postoperatively, patients experienced transient cortical blindness, which in all cases spontaneously resolved during the course of several days to weeks. They provide a comprehensive description of the presentation and surgical management of falcotentorial meningiomas.
An excellent outcome can be expected when surgery is predicated on detailed preoperative neuroimaging and knowledge of the nuances of the surgical technique 14).
Okami et al. present four surgical cases. An occipital transtentorial approach was used in three cases, and a combined midline occipital and suboccipital approach in one case. Total tumour excision was impossible in two cases because of engulfing deep venous structures including the great vein of Galen. Postoperative Gamma knife radiosurgery was performed in these two cases. On the other hand, a posteriorly located tumour was relatively easy to remove, and macroscopic total removal was accomplished. In conclusion, precise microvascular anatomical knowledge is indispensable to satisfactorily excise meningiomas in the falcotentorial area without significant morbidity 15).
Asari et al. describe the clinical features, neuroimaging studies, and results of surgical treatment of meningiomas of the falcotentorial junction and clarify the characteristics of this lesion based on a review of the literature and seven patients treated at their institution. The most common symptoms resulted from intracranial hypertension. Upward-gaze palsy appeared in only one patient. Computerized tomography (CT) showed no specific findings, but there was no evidence of edema around the tumor. Magnetic resonance (MR) imaging revealed a round, smooth-bordered mass with a peritumoral rim, without edema, and showing marked contrast enhancement. The multiplanar capability of MR imaging delineated the relationship between the tumor and adjacent structures better than did CT. Detailed knowledge of the vascular structures, especially evidence of occlusion of the galenic venous system and the development of collateral venous channels, is critical for successful surgery; stereoscopic cerebral angiography is necessary to achieve this aim. The seven patients described developed five types of collateral venous channels: through the basal vein of Rosenthal to the petrosal vein, through the veins on the medial surface of the parietal and occipital lobes to the superior sagittal sinus, through superficial anastomotic veins, through veins of the posterior fossa to the transverse or straight sinus, and through the falcian veins to the superior sagittal sinus. The first three types mainly developed after occlusion of the galenic system. The tumors were removed through the occipital transtentorial approach with a large window at the posterior part of the falx. A favorable prognosis for patients undergoing surgical treatment of falcotentorial junction meningiomas can be expected if detailed neuroimaging studies and microsurgical techniques are used 16).
The tumors were removed subtotally or totally via an occipital interhemispheric transtentorial approach and/or infratentorial supracerebellar approach. The postoperative courses were uneventful, and no neurological deficit was detected postoperatively. Pineal region tumors with a maximum diameter of 5 cm or larger should be operated on via a unilateral or bilateral occipital interhemispheric transtentorial approach, regardless of the angiographic findings, because this permits a wide operative field and can be followed, if necessary, by an infratentorial supracerebellar approach. Selection of the operative approach for a relatively small pineal region tumor should depend on the angiographic findings: downward displacement of the bilateral internal cerebral veins and the great vein of Galen indicates an occipital interhemispheric transtentorial approach, whereas upward displacement indicates an infratentorial supracerebellar approach 17).
One representative case of falcotentorial meningioma treated through an anterior interhemispheric transsplenial approach is also described. Among the interhemispheric approaches to the pineal region, the anterior interhemispheric transsplenial approach has several advantages. 1) There are few or no bridging veins at the level of the pericoronal suture. 2) The parietal and occipital lobes are not retracted, which reduces the chances of approach-related morbidity, especially in the dominant hemisphere. 3) The risk of damage to the deep venous structures is low because the tumor surface reached first is relatively vein free. 4) The internal cerebral veins can be manipulated and dissected away laterally through the anterior interhemispheric route but not via the posterior interhemispheric route. 5) Early control of medial posterior choroidal arteries is obtained. The anterior interhemispheric transsplenial approach provides a safe and effective surgical corridor for patients with supratentorial pineal region tumors that 1) extend superiorly, involve the splenium of the corpus callosum, and push the deep venous system in a posterosuperior or an anteroinferior direction; 2) are tentorial and displace the deep venous system inferiorly; or 3) originate from the splenium of the corpus callosum 18).
Kawashima et al. reported, in anatomic studies, a occipital transtentorial approach: the occipital bi-transtentorial/falcine approach, to treat such lesions. Gusmão et al. present a patient with a large falcotentorial meningioma, located bilaterally in the posterior incisural space. The occipital bi-transtentorial/falcine approach allowed an excellent surgical exposure and complete tumor removal with an excellent patient outcome 19).
Advances in robotic medicine have been adopted by various surgical subspecialties as the benefits of this technology become more readily apparent: precision in narrow operative windows, tremor controlled movements, and modestly improved outcomes, among others.
Robotic manipulators easily allow to achieve great precision, reliability, and rapidity in the positioning of surgical instruments or devices in the brain. The aim of a work was to experimentally verify a fully automatic “no hands” surgical procedure. The integration of neuroimaging to data for planning the surgery, followed by application of new specific surgical tools, permitted the realization of a fully automated robotic implantation of leads in brain targets. An anthropomorphic commercial manipulator was utilized. In a preliminary phase, a software to plan surgery was developed, and the surgical tools were tested first during a simulation and then on a skull mock-up. In such a way, several tools were developed and tested, and the basis for an innovative surgical procedure arose. The final experimentation was carried out on anesthetized “large white” pigs. The determination of stereotactic parameters for the correct planning to reach the intended target was performed with the same technique currently employed in human stereotactic neurosurgery, and the robotic system revealed to be reliable and precise in reaching the target. The results of this work strengthen the possibility that a neurosurgeon may be substituted by a machine, and may represent the beginning of a new approach in the current clinical practice. Moreover, this possibility may have a great impact not only on stereotactic functional procedures but also on the entire domain of neurosurgery 1).
In the case of surgery of the skull base, it has just emerged from an experimental phase.
Neurosurgery is one of the first organ systems in which robotic surgery can play a role, due to the high precision that is required to localize and manipulate within the brain, and the relatively fixed landmarks of the cranial anatomy.
Interest in robotic endoscopic surgery is high because of the small size of the incisions, cosmetic advantages, less invasive surgical techniques, decreased scar tissue, shorter duration of hospitalization and increased cost-effectiveness 4).
see Robotic forceps
Vascular neurosurgery, in particular, remains open to newer and more cutting edge treatment options for complex pathologies, and robotics may be on the horizon for such advances.
Menaker et al. from the Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA. seeked to provide a broad overview of these innovations in vascular neurosurgery for both practitioners well acquainted with robotics and those seeking to become more familiar. Technologies under development for cerebrovascular and endovascular neurosurgery include robot assisted angiography, guided operative microscopes, coil insertion systems, and endoscopic clipping devices. Additionally, robotic systems in the fields of interventional cardiology and radiology have potential applications to endovascular neurosurgery but require proper modifications to navigate complex intracerebral vasculature. Robotic technology is not without drawbacks, as broad implementation may lead to increased cost, training time, and potential delays in emergency situations. Further cultivation of current multidisciplinary technologies and investment into newer systems is necessary before robotics can make a sizable impact in clinical practice 8).