Hydrocephalus associated with vestibular schwannomas: management options and factors predicting the outcome

Functional outcomes after retrosigmoid approach to the cerebellopontine angle: Observations from a single-center experience of over 13 years

Introduction

Accessing the posterior base of the skull is complex because of the vital neurovascular structures in the area. However, the retrosigmoid approach (RSA) offers a solution to this challenge.

Research question

To analyze surgical outcome of RSA.

Material and methods

This study involved a retrospective review of patient charts from a single center, focusing on the surgical procedure and outcomes following the operation.

Results

The study included 517 patients suffering from conditions like vestibular schwannomas (VS), metastatic cancers, and trigeminal neuralgia. The most frequent symptoms reported were balance disorders (42.7%), hearing loss (36.5%), walking difficulties (21.2%), headaches (18.9%), facial pain (17.1%), issues with trigeminal nerve function (14.1%), cerebellar dysfunction (13.5%), and facial nerve paralysis (10.2%). The rate of complications stood at 21.1%, with 11.3% of patients needing revision surgery. The median score on the Clavien-Dindo scale was 2, and the rate of mortality related to surgery was 1.0%. Permanent symptom improvement was seen in 72.1% of cases. Temporary new deficits occurred in 43.2% of patients, with facial nerve paralysis being the most common (14.1%). No significant correlation was found between the size of the craniotomy and the extent of tumor resection (p = 0.155), except in the case of VS (p = 0.041). Larger craniotomy sizes were associated with higher rates of complications (p = 0.016), especially CSF leaks (p = 0.006). Complications significantly affected the likelihood and number of new deficits (p < 0.001 for both), particularly postoperative bleeding (p = 0.019, p = 0.001), CSF leaks (p = 0.026, p = 0.039), and hydrocephalus (p = 0.050, p = 0.007).

Conclusions

The potential for complications related to the surgical approach cannot be overlooked. The size of the tumor should not dictate larger surgical approaches due to the associated increase in postoperative complications; a tailored approach that considers the precise tumor location and pathology is crucial for optimizing postoperative outcomes.

Hidden intra-meatal CSF fistula related to VP shunt as a cause for fatal tension pneumocephalus after vestibular schwannoma resection

BACKGROUND

Cerebrospinal fluid (CSF) leak through petrosal air cells is a known complication after drilling the posterior wall of the internal acoustic canal (IAC) for resection of vestibular schwannoma (VS). Whereas mild pneumocephalus is common after retrosigmoid craniotomy, tension pneumocephalus has been rarely documented.

OBJECTIVE

To testify a case of fatal tension pneumocephalus after VS resection in a patient with ventriculo-peritoneal (VP) shunt and to propose possible recommendations to limit the risk of this dramatic complication.

METHODS

A case of fatal tension pneumocephalus after VS resection in presence of hidden CSF fistula is illustrated with pre- and post-operative images.

RESULTS

In the uneventful situation of concomitant post-operative CSF fistula in presence of VP shunt, tension pneumocephalus may occur. The negative pressure created by the shunt system and the presence of osteo-dural defect allow the air to enter and, at the same time, prevent the outflow.

CONCLUSION

After VS resection, tension pneumocephalus can occur as a consequence of CSF fistula from petrosal air cells in the presence of functioning VP shunt. Precautions as pre-operative increase to 'virtual-off' the pressure of the valve, subsequences CT scans after surgery and sealing of the petrous air cells are recommended to avoid such as fatal complication.

Hydrocephalus in patients with vestibular schwannoma

BACKGROUND

Hydrocephalus (HC) is common in patients with vestibular schwannoma (VS). This can be managed with a cerebrospinal fluid (CSF) diversion procedure prior to VS resection or with VS resection, keeping CSF diversion in reserve unless required postoperatively. No clear consensus exists as to which approach is superior. This study identifies factors predictive of the development of HC, and analyses outcomes for those managed with primary CSF resection versus tumour resection.

METHODS

Single-centre retrospective cohort study of 204 consecutive adult patients with a unilateral VS from May 2009 to June 2021. Data was collected on patient and tumour demographics, management, and outcome.

RESULTS

204 patients, with a mean age at presentation of 59.5 (21-83), with 50% female, and a mean follow-up of 7.5 years (1.8-13.9) were included. 119 were managed conservatively, 36 with stereotactic radiosurgery only, and 49 with surgery. 30 (15%) patients had radiological HC, of which 23 (77%) were obstructive, and 7 (23%) were communicating. Maximum intracranial tumour diameter and Koos grade were higher in patients with HC. Of the patients with HC the majority (20, 67%) were managed initially with CSF diversion, with 12 patients undergoing subsequent tumour resection, and three patients avoiding primary resection. Nine (30%) were managed with primary surgical resection, of whom three required subsequent CSF diversion. Complication rates and Modified Rankin Scale (MRS) were comparable or lower in the CSF diversion group (8%, MRS ≤2 = 83%), versus the primary resection group (67%, MRS ≤2 = 67%), and the primary surgical resection without HC group (25%, MRS ≤2 = 86%).

CONCLUSIONS

CSF diversion prior to tumour resection is a safe and acceptable strategy compared to primary VS resection, with improved outcomes and reduced surgical complications. Randomized studies and national databases are needed to determine the long-term outcomes of patients treated with CSF diversion versus primary resection.

Supratentorial cerebrospinal fluid diversion using image-guided trigonal ventriculostomy during retrosigmoid craniotomy for cerebellopontine angle tumors

Background

Cerebellar contusion, swelling and herniation is frequently encoutered upon durotomy in patients undergoing retrosigmoid craniotomy for cerebellopontine angle (CPA) tumors, despite using standard methods to obtain adequate cerebellar relaxation.

Objective

The aim of this study is to report an alternative cerebrospinal fluid (CSF)-diversion method using image-guided ipsilateral trigonal ventriculostomy.

Methods

Single-center retro- and prospective cohort study of n = 62 patients undergoing above-mentioned technique. Prior durotomy, CSF-diversion was performed to the point where the posterior fossa dura was visibly pulsatile. Outcome assessment consisted of the surgeon's intra- and postoperative clinical observations, and postoperative radiological imaging.

Results

Fifty-two out of n = 62 (84%) cases were eligible for analysis. The surgeons consistently reported successful ventricular puncture and a pulsatile dura prior durotomy without cerebellar contusion, swelling or herniation through the dural incision in n = 51/52 (98%) cases. Forty-nine out of n = 52 (94%) catheters were placed correctly within the first attempt, with the majority of catheter tips (n = 50, 96%) located intraventricularly (grade 1 or 2). In n = 4/52 (8%) patients, postoperative imaging revealed evidence of a ventriculostomy-related hemorrhage (VRH) associated with an intracerebral hemorrhage [n = 2/52 (4%)] or an isolated intraventricular hemorrhage [n = 2/52 (4%)]. However, these hemorrhagic complications were not associated with neurological symptoms, surgical interventions or postoperative hydrocephalus. None of the evaluated patients demonstrated radiological signs of upward transtentorial herniation.

Conclusion

The method described above efficiently allows CSF-diversion prior durotomy to reduce cerebellar pressure during retrosigmoid approach for CPA tumors. However, there is an inherent risk of subclinical supratentorial hemorrhagic complications.

How to position the patient? A meta-analysis of positioning in vestibular schwannoma surgery via the retrosigmoid approach

Objective

Patient positioning is a matter of ongoing debate in the surgical treatment of vestibular schwannoma (VS). Main endpoints of this discussion are preservation of facial nerve functioning, extent of resection, and complications. In this meta-analysis, we aim to investigate the impact of patient positioning on VS surgery via the retrosigmoid approach.

Methods

We searched for eligible comparative trials on PubMed, Cochrane library, and Web of Science. Positioning groups were compared regarding facial nerve outcome, extent of resection, postoperative hydrocephalus, postoperative CSF leaks, perioperative venous air embolism, and perioperative mortality. Two groups of positions were defined, and the following positions were allocated to those groups: (1) Semi-sitting and Sitting-position; (2) Lateral position, supine position with extensive head rotation, lateral oblique (=Fukushima/Three-quarter prone), and park-bench position.

Results

From 374 full-text screenings, 7 studies met the criteria and were included in our meta-analysis comprising 1640 patients. Our results demonstrate a significantly better long-term (≥6 months) outcome of the facial nerve after VS surgery in the semi-sitting positioning (OR: 1.49, 95%CI: 1.03-2.15, p = 0.03). Positioning did not influence the extent of resection, rate of postoperative CSF leaks, and the presence of a postoperative hydrocephalus. Overall incidence of venous air embolisms was significantly associated with VS surgery in sitting positioning (OR: 6.77, 95% CI: 3.66-12.54, p < 0.00001). Perioperative mortality was equal among both positioning groups.

Conclusion

Semi-sitting positioning seems to be associated with an improved facial nerve outcome after VS surgery via the retrosigmoid approach. Venous air embolisms are significantly more often observed among VS patients who underwent surgery in the sitting position, but the perioperative mortality is equal in both positioning groups. Both positioning groups are a safe procedure. Multicentric prospective randomized trials are needed to evaluate the risk-benefit ratio of each positioning in VS surgery via the retrosigmoid approach.

Duraplasty with autologous nuchal ligament fascia to reduce postoperative complications in pediatric patients undergoing neoplasia resection with a suboccipital midline approach

OBJECTIVE

The authors sought to explore the safety and efficacy of an autologous nuchal ligament for dural repair in pediatric patients undergoing tumor resection through a suboccipital midline approach.

METHODS

Pediatric patients diagnosed with posterior fossa neoplasia who underwent surgery through a suboccipital midline approach were retrospectively reviewed. The patients were divided into artificial graft and autograft groups according to whether artificial duraplasty material or autologous nuchal ligament was used to repair the dura. Postoperative complications were reviewed and analyzed, including CSF leak, pseudomeningocele, and meningitis, during hospitalization and follow-up. Univariate and multivariate logistic regression analyses were used to investigate the relationship between duraplasty material and postoperative complications, as well as other risk factors for postoperative complications. Furthermore, multinomial logistic regression analysis was used to clarify which postoperative complications the autologous nuchal ligament tended to reduce.

RESULTS

This retrospective study included 66 pediatric patients who underwent tumor resection through a suboccipital midline approach. The clinical baseline characteristics were comparable between the two groups. The results showed that the autograft group had significantly fewer postoperative complications, especially pseudomeningocele, compared with the artificial graft group. Moreover, the time required to repair the dura in the autograft group was significantly less than that in the artificial graft group. Further results revealed that the duraplasty material, ependymoma, preoperative severe hydrocephalus requiring an external ventricular drain (EVD), and postoperative hydrocephalus exacerbation were independent risk factors for postoperative complications. In particular, the autologous fascia of the nuchal ligament tended to reduce pseudomeningocele more than CSF leak and meningitis. However, compared with pseudomeningocele and CSF leak, both ependymoma and postoperative hydrocephalus exacerbation were more likely to increase the occurrence of meningitis. In contrast, preoperative severe hydrocephalus requiring EVD led to increased rates of postoperative complications.

CONCLUSIONS

For pediatric patients with intracranial tumors who need to undergo resection through a suboccipital midline approach, dural repair using the nuchal ligament is safe, cost-effective, and time saving and significantly reduces postoperative complications.

Vision Deterioration and Hydrocephalus: Rare Presentations of Vestibular Schwannoma and Evolution of Management

Introduction The incidence of vestibular schwannoma is reported as 12 to 54 new cases per million per year, increasing over time. These patients usually present with unilateral sensorineural hearing loss, tinnitus, or vertigo. Rarely, these patients present with symptoms of hydrocephalus or vision changes.

Objective The study aimed to evaluate the surgical management of vestibular schwannoma at a single institution and to identify factors that may contribute to hydrocephalus, papilledema, and the need for pre-resection diversion of cerebrospinal fluid.

Patients and Methods A retrospective review examining the data of 203 patients with vestibular schwannoma managed with surgical resection from May 2008 to May 2020. We stratified patients into five different groups to analyze: tumors with a diameter of ≥40 mm, clinical evidence of hydrocephalus, and of papilledema, and patients who underwent pre-resection cerebrospinal fluid (CSF) diversion.

Results From May 2008 to May 2020, 203 patients were treated with surgical resection. Patients with tumors ≥40 mm were more likely to present with visual symptoms (p < 0.001). Presentation with hydrocephalus was associated with larger tumor size (p < 0.001) as well as concomitant visual symptoms and papilledema (p < 0.001). Patients with visual symptoms presented at a younger age (p = 0.002) and with larger tumors (p < 0.001).

Conclusion This case series highlights the rare presentation of vision changes and hydrocephalus in patients with vestibular schwannoma. We recommend urgent CSF diversion for patients with visual symptoms and hydrocephalus, followed by definitive resection. Further, vision may still deteriorate even after CSF diversion and tumor resection.

Association of Patient Frailty With Vestibular Schwannoma Resection Outcomes and Machine Learning Development of a Vestibular Schwannoma Risk Stratification Score

BACKGROUND

Patient frailty is predictive of higher neurosurgical morbidity and mortality. However, existing frailty measures are hindered by lack of specificity to neurosurgery.

OBJECTIVE

To analyze the association between 3 risk stratification scores and outcomes for nationwide vestibular schwannoma (VS) resection admissions and develop a custom VS risk stratification score.

METHODS

We identified all VS resection admissions in the National Inpatient Sample (2002-2017). Three risk stratification scores were analyzed: modified Frailty Index-5, modified Frailty Index-11(mFI-11), and Charlson Comorbidity Index (CCI). Survey-weighted multivariate regression evaluated associations between frailty and inpatient outcomes, adjusting for patient demographics, hospital characteristics, and disease severity. Subsequently, we used k-fold cross validation and Akaike Information Criterion-based model selection to create a custom risk stratification score.

RESULTS

We analyzed 32 465 VS resection admissions. High frailty, as identified by the mFI-11 (odds ratio [OR] = 1.27, P = .021) and CCI (OR = 1.72, P < .001), predicted higher odds of perioperative complications. All 3 scores were also associated with lower routine discharge rates and elevated length of stay (LOS) and costs (all P < .05). Our custom VS-5 score (https://skullbaseresearch.shinyapps.io/vs-5_calculator/) featured 5 variables (age ≥60 years, hydrocephalus, preoperative cranial nerve palsies, diabetes mellitus, and hypertension) and was predictive of higher mortality (OR = 6.40, P = .001), decreased routine hospital discharge (OR = 0.28, P < .001), and elevated complications (OR = 1.59, P < .001), LOS (+48%, P < .001), and costs (+23%, P = .001). The VS-5 outperformed the modified Frailty Index-5, mFI-11, and CCI in predicting routine discharge (all P < .001), including in a pseudoprospective cohort (2018-2019) of 3885 admissions.

CONCLUSION

Patient frailty predicted poorer inpatient outcomes after VS surgery. Our custom VS-5 score outperformed earlier risk stratification scores.

Long-term risk of shunt failure after brain tumor surgery

Long-term risks and survival times of ventriculoperitoneal (VP) shunts implanted due to hydrocephalus (HC) after craniotomy for brain tumors are largely unknown. The aim of this study was to establish the overall VP shunt survival rates during a decade after shunt insertion and to determine risks of shunt failure after brain tumor surgery in the long-term period. In this population-based cohort from a well-defined geographical region, all adult patients (> 18 years) from 2004 to 2013 who underwent craniotomies for intracranial tumors leading to VP shunt dependency were included. Our brain tumor database was cross-linked to procedure codes for shunt surgery (codes AAF) to extract brain tumor patients who became VP shunt dependent after craniotomy. The VP shunt survival time, i.e. the shunt longevity, was calculated from the day of shunt insertion after brain tumor surgery until the day of its failure. A total of 4174 patients underwent craniotomies, of whom 85 became VP shunt dependent (2%) afterwards. Twenty-eight patients (33%) had one or more shunt failures during their long-term follow-up, yielding 1-, 5-, and 10-year shunt success rates of 77%, 71%, and 67%, respectively. Patient age, sex, tumor location, primary/repeat craniotomy, placement of external ventricular drainage (EVD), ventricular entry, post-craniotomy hemorrhage, post-shunting meningitis/infection, and multiple shunt revisions were not statistically significant risk factors for shunt failure. Median shunt longevity was 457.5 days and 21.5 days for those with and without pre-craniotomy HC, respectively (p < 0.01). This study can serve as benchmark for future studies.

Large and small vestibular schwannomas: same, yet different tumors

BACKGROUND

Vestibular schwannomas (VS) present at variable size with heterogeneous symptomatology. Modern treatment paradigms for large VS include gross total resection, subtotal resection (STR) in combination with observation, and/or radiation to achieve optimal function preservation, whereas treatment is felt to be both easier and safer for small VS. The objective is to better characterize the presentation and surgical outcomes of large and small VS.

METHODS

We collected data of patients who had surgically treated VS with a posterior fossa diameter of 4.0 cm or larger (large tumor group, LTG) and smaller than 1.0 cm in cisternal diameter (small tumor group, STG). Statistical significance was defined as p < 0.05.

RESULTS

LTG included 48 patients (average tumor size: 44.9 mm) and STG 38 (7.9 mm). Patients in STG presented more frequently with tinnitus and sudden hearing loss. Patients in LTG underwent more STR than STG (50.0% vs. 2.6%, p < 0.0001). LTG had more complications (31.3% vs. 13.2%, p = 0.049). Postoperative facial nerve function in STG was significantly better than LTG. STG had better hearing preoperatively (p < 0.0001) and postoperatively than LTG (p = 0.0002). Postoperative headache was more common in STG (13.2% vs. 2.1%, p = 0.045). The rate of recurrence/progression needing treatment was not statistically different between the groups (12.5% in LTG vs. 7.9% in STG, p = 0.49). Those patients who required periprocedural cerebrospinal fluid diversion had higher risk of infection (20.8% vs 4.8%, p = 0.022).

CONCLUSION

Large and small VS present differently. LTG showed more unsatisfactory outcomes in facial nerve function and postoperative hearing despite maximal efforts undertaken toward function-preservation strategy; however, similar tumor control was achieved.

Characteristics and management of hydrocephalus in adult patients with cerebellar glioblastoma: lessons from a French nationwide series of 118 cases

The characteristics of hydrocephalus associated with cerebellar glioblastoma (cGB) remain poorly known. The objectives were to describe the occurence of hydrocephalus in a French nationwide series of adult patients with cGB, to identify the characteristics associated with hydrocephalus and to analyze the outcomes associated with the different surgical strategies, in order to propose practical guidelines. Consecutive cases of adult cGB patients prospectively recorded into the French Brain Tumor Database between 2003 and 2017 were screened. Diagnosis was confirmed by a centralized neuropathological review. Among 118 patients with cGB (mean age 55.9 years), 49 patients (41.5%) presented with pre-operative hydrocephalus. Thirteen patients (11.0%) developed acute (n=7) or delayed (n=6) hydrocephalus postoperatively. Compared to patients without hydrocephalus at admission, patients with hydrocephalus were younger (52.0 years vs 58.6 years, p=0.03) and underwent more frequently tumor resection (93.9% vs 73.9%, p=0.006). A total of 40 cerebrospinal-fluid diversion procedures were performed, including 18 endoscopic third ventriculostomies, 12 ventriculoperitoneal shunts and 10 external ventricular drains. The different cerebrospinal-fluid diversion options had comparable functional results and complication rates. Among the 89 patients surgically managed for cGB without prior cerebrospinal-fluid diversion, 7 (7.9%) were long-term shunt-dependant. Hydrocephalus is frequent in patients with cGB and has to be carefully managed in order not to interfere with adjuvant oncological treatments. In case of symptomatic hydrocephalus, a cerebrospinal-fluid diversion is mandatory, especially if surgical resection is not feasible. In case of asymptomatic hydrocephalus, a cerebrospinal-fluid diversion has to be discussed only if surgical resection is not feasible.

Risk of early failure of VP shunts implanted for hydrocephalus after craniotomies for brain tumors in adults

Risks and survival times of ventriculoperitoneal (VP) shunts implanted due to hydrocephalus after craniotomies for brain tumors are largely unknown. The purpose of this study was to determine the overall timing of VP shunting and its failure after craniotomy for brain tumors in adults. The authors also wished to explore risk factors for early VP shunt failure (within 90 days). A population-based consecutive patient cohort of all craniotomies for intracranial tumors leading to VP shunt dependency in adults (> 18 years) from 2004 to 2013 was studied. Patients with pre-existing VP shunts prior to craniotomy were excluded. The survival time of VP shunts, i.e., the shunt longevity, was calculated from the day of shunt insertion post-craniotomy for a brain tumor until the day of shunt revision requiring replacement or removal of the shunt system. Out of 4774 craniotomies, 85 patients became VP shunt-dependent (1.8% of craniotomies). Median time from craniotomy to VP shunting was 1.9 months. Patients with hydrocephalus prior to tumor resection (N = 39) had significantly shorter time to shunt insertion than those without (N = 46) (p < 0.001), but there was no significant difference with respect to early shunt failure. Median time from shunt insertion to shunt failure was 20 days (range 1–35). At 90 days, 17 patients (20%) had confirmed shunt failure. Patient age, sex, tumor location, primary/secondary craniotomy, extra-axial/intra-axial tumor, ventricular entry, post-craniotomy bleeding, and infection did not show statistical significance. The risk of early shunt failure (within 90 days) of shunts after craniotomies for brain tumors was 20%. This study can serve as benchmark for future studies.

Exploring mechanisms of ventricular enlargement in idiopathic normal pressure hydrocephalus: a role of cerebrospinal fluid dynamics and motile cilia

Idiopathic normal pressure hydrocephalus (iNPH) is considered an age-dependent chronic communicating hydrocephalus associated with cerebrospinal fluid (CSF) malabsorption; however, the aetiology of ventricular enlargement in iNPH has not yet been elucidated. There is accumulating evidence that support the hypothesis that various alterations in CSF dynamics contribute to ventricle dilatation in iNPH. This review focuses on CSF dynamics associated with ventriculomegaly and summarises the current literature based on three potential aetiology factors: genetic, environmental and hydrodynamic. The majority of gene mutations that cause communicating hydrocephalus were associated with an abnormal structure or dysfunction of motile cilia on the ventricular ependymal cells. Aging, alcohol consumption, sleep apnoea, diabetes and hypertension are candidates for the risk of developing iNPH, although there is no prospective cohort study to investigate the risk factors for iNPH. Alcohol intake may be associated with the dysfunction of ependymal cilia and sustained high CSF sugar concentration due to uncontrolled diabetes increases the fluid viscosity which in turn increases the shear stress on the ventricular wall surface. Sleep apnoea, diabetes and hypertension are known to be associated with the impairment of CSF and interstitial fluid exchange. Oscillatory shear stress to the ventricle wall surfaces is considerably increased by reciprocating bidirectional CSF movements in iNPH. Increased oscillatory shear stress impedes normal cilia beating, leading to motile cilia shedding from the ependymal cells. At the lack of ciliary protection, the ventricular wall is directly exposed to increased oscillatory shear stress. Additionally, increased oscillatory shear stress may be involved in activating the flow-mediated dilation signalling of the ventricular wall. In conclusion, as the CSF stroke volume at the cerebral aqueduct increases, the oscillatory shear stress increases, promoting motor cilia shedding and loss of ependymal cell coverage. These are considered to be the leading causes of ventricular enlargement in iNPH.

Gross-total versus near-total resection of large vestibular schwannomas. An institutional experience

OBJECTIVE

We will report our experience of the surgical treatment of large vestibular schwannomas (VSs).

PATIENTS, MATERIALS AND METHODS

We conducted a retrospective study of patients operated on for Koos grade IV VS between 2007 and 2015 at the Department of Neurosurgery, Emergency County Hospital, Târgu Mureş, Romania. We studied the general preoperatory clinical data, the preoperative and postoperative facial nerve status, preoperative hearing on the affected side, and any postoperative complications, including death.

RESULTS

Sixty-six cases were included in our study. The mean age was 52.95 years and 66.7% (n=44) of the sample were female. All patients had suffered from tinnitus and this had been followed by loss of serviceable hearing on the affected side in 89.4% (n=59) of cases. Preoperative facial palsy was found in 53% (n=35) of patients. The mean tumor size was 40.35 mm. Gross-total resection (GTR) was achieved in 24 (36.36%) cases, while near-total resection (NTR) was obtained in 42 (63.64%) cases. New-onset facial palsy or degradation of the preoperative facial deficit occurred in 12 (18.18%) cases, most of whom were patients with a GTR (n=9, 37.5%). This was statistically significant. There were no significant postoperative differences between the GTR and NTR groups. There was one death in the GTR group.

CONCLUSIONS

We conclude that near-total tumor removal provides good surgical results and better postsurgical quality of life for patients when compared to gross-total tumor resection. Therefore, this should be the end goal of the resection of large VSs.

Treatment Outcome of Hydrocephalus Associated with Vestibular Schwannoma

BACKGROUND AND PURPOSE

Managing hydrocephalus in patients with vestibular schwannoma (VS) is controversial. We evaluated the clinical factors associated with hydrocephalus.

METHODS

Between 2000 and 2019, 562 patients with VS were treated at our institute. We applied endoscopic third ventriculostomy (ETV), external ventricular drainage (EVD), and ventriculoperitoneal (VP) shunts to patients with hydrocephalus. The relationships of patient, tumor, and surgical variables with the hydrocephalus outcome were assessed.

RESULTS

Preoperative hydrocephalus (Evans ratio ≥0.3) was present in 128 patients. Six patients who received a preresectional VP shunt were excluded after analyzing the hydrocephalus outcome. Seven of the remaining 122 patients had severe hydrocephalus (Evans ratio ≥0.4). Primary tumor resection, VP shunting, ETV, and EVD were performed in 60, 6, 57, and 5 patients, respectively. The hydrocephalus treatment failure rate was highest in the EVD group. Persistent hydrocephalus was present in five (8%) and seven (12%) patients in the primary resection and ETV groups, respectively. Multivariate analysis revealed that severe hydrocephalus, the cystic tumor, and the extent of resection (subtotal resection or partial resection) were associated with hydrocephalus treatment failure.

CONCLUSIONS

Larger ventricles and a higher cystic portion are predictive of persistent hydrocephalus. We recommend attempting near-total tumor resection in patients with VS.

Retrospective Analytic Study of Neurosurgical Patients Who Developed Postoperative Hydrocephalus

Objective This article discusses the causes, primary pathologies, management, and prognosis of patients who did not have hydrocephalus in preoperative stage, underwent definitive surgical procedure, and developed postoperative hydrocephalus requiring cerebrospinal fluid (CSF) diversion procedures.

Methods Retrospective data collection was done from operation theatre (OT) department database and patient records were obtained for the patients after, related literature was searched, all possible risk factors were analyzed, and our results were compared with other studies.

Results A total of 80 cases were found eligible for the study. Decompressive craniectomy was the most common cause followed by aneurysmal subarachnoid hemorrhage (SAH), intraventricular, and cerebellopontine angle (CPA) tumors. Rate of postsurgical hydrocephalus was 15 to 16%. Cases of decompressive craniectomy presented late, only few cases required diversion procedures during the immediate postop period, mostly aneurysm cases and tumors bed bleed. Out of total 6 mortalities, none of them were directly attributable to hydrocephalus. Since most patient presented after initial stabilization, permanent ventriculoperitoneal shunting was found to be the best option.

Conclusion Cases of decompression surgery should be under vigilant follow-up after discharge and even after cranioplasty for risk of development of hydrocephalus and requirement of permanent shunting. Cases with intraventricular hemorrhage or SAH should be considered as future candidate with risk of developing hydrocephalus. Lamina terminalis opening whenever possible results in favorable outcome in cases of anterior circulation aneurysms. CSF protein analysis in cases of intraventricular and CPA tumors should be done whenever possible, preferably routinely.

Management von Patienten mit Vestibularisschwannomen Typ IV

Hintergrund Vestibularisschwannome (VS) sind benigne Tumoren, die anhand der Hannover-Klassifikation bzw. der Koos-Klassifizierung eingeteilt werden. Trotz der umfangreichen Literatur sind die Klinik und die Behandlungskonzepte speziell bei großen VS selten beschrieben.

Material und Methoden Zwischen 2003 und 2018 wurden 61 Patienten mit VS Typ IV durch die Arbeitsgruppe Schädelbasischirurgie am Klinikum Dortmund behandelt. Die radiologischen und klinischen Daten wurden retrospektiv ausgewertet. Zudem erfolgte eine Subgruppenanalyse zwischen Patienten mit und ohne Kompression des IV. Ventrikels.

Ergebnisse Neben einer Hörminderung bei 55 Patienten (90 %) hatten die meisten Patienten multiple Symptome wie eine Trigeminusaffektion bei 16 (26 %), eine Fazialisparese bei 7 (12 %), eine Ataxie bei 27 (45 %) und Symptome eines Hirndruckanstiegs durch einen Hydrozephalus bei 4 Patienten (7 %). Bei Patienten mit einem VS Typ IVb wurde signifikant häufiger eine Ataxie, eine tonsilläre Herniation bzw. ein Hydrozephalus festgestellt. Eine komplette Resektion wurde in 48 Patienten (78 %) erreicht und eine weitestgehende Tumorentfernung in 12 Patienten (20 %). In der Langzeituntersuchung zeigten 90 % einen günstigen Outcome bezüglich des Nervus facialis (House-und-Brackman-Grad I–III). 6 Patienten (10 %) benötigten einen dauerhaften ventrikulo-peritonealen Shunt. Mehr als 90 % der Patienten erzielten einen Karnofsky-Index > 70 %.

Diskussion VS Typ IV sind häufig assoziiert mit Hydrozephalus, Ataxie, multiplen Hirnnervenausfällen und gelegentlich Zeichen eines intrakraniellen Druckanstiegs. Die primäre mikrochirurgische Resektion ist weiterhin eine entscheidende Therapieoption.

Characteristics and management of hydrocephalus associated with vestibular schwannomas: a systematic review

Hydrocephalus (HC) can be associated with vestibular schwannoma (VS) at presentation. Although spontaneous resolution of HC after VS removal is reported, first-line treatment is varied including preoperative ventriculoperitoneal (VP) shunt, external ventricular drainage (EVD), or lumbar drainage (LD). We performed a systematic review to clarify optimal management of HC associated with VS at presentation, as well as characteristics of patients with initial and persistent HC after VS removal, and prevalence of HC associated with VS. Fourteen studies were included. Patients were grouped according to the timing of HC treatment. The overall rate of VP shunts was 19.4%. Among patients who received VS removal as first-line treatment, 6.9% underwent permanent shunts. In a subgroup of 132 patients (studies with no-aggregate data), t test analysis for mean tumor size (P = 0.02) and mean CSF protein level (P < 0.001) demonstrated statistically significant differences between patients with resolved HC (3.48 cm and 201 mg/dL) and patients with persistent HC (2.46 cm and 76.8 mg/dL) after VS resection. Transient treatment of HC using EVD or LD further resolved the HC in 87.5% and 82.9% of patients, respectively, before and after VS removal. The overall prevalence of HC associated with VS in a population of 2336 patients was 9.3%. Schwannoma removal as first-line treatment is justified by its low rate of persistent HC requiring VP shunt (roughly 7%). Patients with smaller VS and lower CSF proteins present higher risk of persistent HC after schwannoma removal. Temporary treatment of HC contributes to its resolution, both before and after VS removal.

Imaging features and classification of peritumoral edema in vestibular schwannoma

BACKGROUND

Peritumoral edema (PTE) is rarely present in patients with vestibular schwannomas (VS). We studied the correlation between radiological tumor characteristics and the presence of edema, describe its magnetic resonance imaging features and classify the different edema patterns.

METHODS

We analysed 605 consecutive patients treated for VS at our Institute. PTE was found in 30 patients, studied on fluid attenuated inversion recovery sequences and categorised as involving the brachium pontis, cerebellum and/or brainstem. Tumor volume, shape, surface, internal structure and axis of growth were evaluated and compared to a matched series of 30 patients without PTE.

RESULTS

In our population of patients, 5% showed PTE. Edema involved the brachium pontis in 22 cases (88%), cerebellum in 15 (60%) and brainstem in 3 (12%). PTE was classified as mild (one region involved), moderate (two regions) and severe (three regions). Edema was present not only perpendicular to the major tumor growth axis but also parallel to it (91%). The difference between the two groups in regards to tumor shape and surface was not significant. We found no correlation between tumor and edema volumes.

CONCLUSIONS

VS can cause PTE, but its incidence is less frequent than in skull base meningiomas. PTE involves most frequently the brachium pontis, followed by the cerebellum and brainstem. Its occurrence correlates with tumor size but not with other radiological VS features. PTE is not always located perpendicular to the major axis of tumor growth, which indicated that the compressive theory proposed for meningiomas is not plausible explanation for its manifestation.

Hydrocephalus Associated with Large Vestibular Schwannoma: Management Options and Factors Predicting Requirement of Cerebrospinal Fluid Diversion after Primary Surgery

Objective:

Obstructive hydrocephalus (HCP) related to vestibular schwannoma occurs in large tumors compressing the fourth ventricle. Symptoms related to HCP are expected to alleviate after resection of the tumor and decompression of the cerebrospinal fluid (CSF) pathways. However, some patients may require permanent cerebrospinal diversion even after surgery due to persistent HCP. In this study, the authors try to find out the factors associated with the requirement of CSF diversion after vestibular schwannoma surgery in cases of persistent HCP.

Materials and Methods:

This was a retrospective study involving 193 cases of vestibular schwannoma operated between 2010 and 2013 in our institute. Cases that underwent ventriculoperitoneal (VP) shunts before surgery were compared to cases which were operated directly. In cases where vestibular schwannomas were operated without prior VP shunts, factors which were associated with persistent postoperative HCP were analyzed.

Results:

Comparing the group who underwent direct surgery to the group who underwent VP shunt before definitive vestibular schwannoma surgery, the facial nerve preservation rates and surgical morbidity rates were comparable. In cases who underwent direct surgery, 10 out of 75 patients required postoperative permanent CSF diversion. Older age, male gender, duration of symptoms, larger tumor size, solid lesions, severe HCP, and clinical features of HCP were associated with postoperative requirement of CSF diversion but were not statistically significant. The most significant factor that correlated with the need for additional HCP treatment was the presence of postoperative hematoma of volume >10cc.

Conclusions:

Primary tumor removal is the optimal treatment for vestibular schwannoma associated with HCP. Postoperative hematoma may warrant close observation as these patients are at an increased risk of persistence of HCP.

The effect of tumor removal via craniotomies on preoperative hydrocephalus in adult patients with intracranial tumors

The efficacy of tumor removal via craniotomies on preoperative hydrocephalus (HC) in adult patients with intracranial tumors is largely unknown. Therefore, we sought to evaluate the effect of tumor resection in patients with preoperative HC and identify the incidence and risk factors for postoperative VP shunt dependency. All craniotomies for intracranial tumors at Oslo University Hospital in patients ≥ 18 years old during a 10-year period (2004-2013) were reviewed. Patients with radiologically confirmed HC requiring surgery and subsequent development of shunt dependency were identified by cross-linking our prospectively collected tumor database to surgical procedure codes for hydrocephalus treatment (AAF). Patients with preexisting ventriculoperitoneal (VP) shunts (N = 41) were excluded. From 4774 craniotomies performed on 4204 patients, a total of 373 patients (7.8%) with HC preoperatively were identified. Median age was 54.4 years (range 18.1-83.9 years). None were lost to follow-up. Of these, 10.5% (39/373) required permanent CSF shunting due to persisting postoperative HC. The risk of becoming VP shunt dependent in patients with preexisting HC was 7.0% (26/373) within 30 days and 8.9% (33/373) within 90 days. Only secondary (repeat) surgery was a significant risk factor for VP shunt dependency. In this large, contemporary, single-institution consecutive series, 10.5% of intracranial tumor patients with preoperative HC became shunt-dependent post-craniotomy, yielding a surgical cure rate for HC of 89.5%. To the best of our knowledge, this is the first and largest study regarding postoperative shunt dependency after craniotomies for intracranial tumors, and can serve as benchmark for future studies.

Clinical features, microsurgical treatment, and outcome of vestibular schwannoma with brainstem compression

Background:

Presenting symptoms, treatment considerations, and outcome are strongly related to the extension of vestibular schwannomas (VS). The aim of the current retrospective study was to analyze the clinical features, microsurgical treatment, and outcome of VS with brainstem compression.

Methods:

Forty-nine patients presented with VS (Hannover grading scale T4a or T4b) in our department. A subgroup analysis was performed among patients without (T4a) and with (T4b) compression and dislocation of the fourth ventricle.

Results:

Patients with type T4b VS presented significantly more often with long tract signs/ataxia (P < 0.05), tonsillar herniation (P < 0.001), and preoperative hydrocephalus (P < 0.01). No significant difference was found between the groups regarding hearing loss and facial nerve, trigeminal nerve, and lower cranial nerve function. Gross total resection was achieved in 83% of the cases, near total resection was achieved in 15% of the cases, and subtotal resection was performed in 2% of the cases. One patient died after massive postoperative bleeding caused by a coagulopathy. At last follow-up, 69% of the patients had excellent facial nerve function (Grade I–II) and the remaining 31% a fair outcome. Six patients (12%) required permanent ventriculoperitoneal shunting. Hearing was preserved in two patients. Forty-six patients (94%) were independent without occasional assistance (Karnofsky scale 70–100%).

Conclusions:

VS with brainstem compression is frequently associated with hydrocephalus, ataxia, long tract signs, multiple cranial nerve disorders, and occasionally, signs of intracranial hypertension. Primary microsurgical resection is an appropriate management option for large VS.

Vascular hyperpermeability as a hallmark of phacomatoses: is the etiology angiogenesis comparable with mechanisms seen in inflammatory pathways? Part I: historical observations and clinical perspectives on the etiology of increased CSF protein levels, CSF clotting, and communicating hydrocephalus: a comprehensive review

Phacomatoses are a special group of familial hamartomatous syndromes with unique neuro-cutaneous manifestations as well as disease characteristic tumors. Neurofibromatosis 2 (NF2) and tuberous sclerosis complex (TSC) are representatives of this family. Vestibular schwannoma (VS) and subependymal giant cell tumor (SGCT) are two of the most common intracranial tumors associated with NF2 and TSC, respectively. These tumors can present with obstructive hydrocephalus due to their location adjacent to or in the ventricles. However, both tumors are also known to have a unique association with an elevated protein concentration in the cerebrospinal fluid (CSF), sometimes in association with non-obstructive (communicating) hydrocephalus (HCP), the causality of which has been unclear. Furthermore, SGCTs have repeatedly been shown to have a predisposition for CSF clotting, causing debilitating obstructions and recurrent malfunctions in shunted patients. However, the exact relation between high protein levels and spontaneous clotting of the CSF is not clear, nor is the mechanism understood by which CSF may clot in SGCTs. Elevated protein levels in the CSF are thought to be caused by increased vascular permeability and dysregulation of the blood-brain barrier. The two presumed underlying pathophysiologic mechanisms for that, in the context of tumorigenesis, are angiogenesis and inflammation. Both mechanisms are correlated to the Pi3K/Akt/mTOR pathway which is a major tumorigenesis pathway in nearly all phacomatoses. In this review, we discuss the influence of angiogenesis and inflammation on vascular permeability in VSs and SGCTs at the phenotypic level as well as their possible genetic and molecular determinants. Part I describes the historical perspectives and clinical aspects of the relationship between vascular permeability, abnormal CSF protein levels, clotting of the CSF, and communicating HCP. Part II describes different cellular and molecular pathways involved in angiogenesis and inflammation in these two tumors and the correlation between inflammation and coagulation. Interestingly, while increased angiogenesis can be observed in both VS and SGCT, inflammatory processes seem more prominent in SGCT. Both pathologies are characterized by different subgroups of tumor-associated macrophages (TAM): the pro-inflammatory, M1 type is predominating in SGCTs while pro-angiogenetic, M2 type is predominating in VSs. We suggest that lack of NF2 protein in VS and lack of TSC1/2 proteins in SGCT determine this fundamental difference between the two tumor types, by defining the predominant TAM type. Since inflammatory reactions and coagulation processes are tightly connected, a "pro-inflammatory state" of SGCT can be used to explain the observed associated enhanced CSF clotting process. These distinct cellular and molecular differences may have direct therapeutic implications on tumors that are unique to certain phacomatoses or those with similar genetics.

A New Method of Directing Endoscope Pathway in Single-Nostril Transpheoidal Approach for Safety by Using Volume Rendering With Thin-Section Computed Tomographic Image

OBJECTIVE

This study aims to locate important structures surrounding the sella node and measure the distances and angles between signalized points by using both three-dimensional reconstruction technique and volume-rendering. These distances and angles can provide more accurate reference for surgeries in pituitary adenomas.

METHODS

Ninty volunteers' skulls were scanned and thin-section computed tomographic images were displayed. The highest point of saddle node on double sides were marked as point A (right) and A1 (left), the highest point of posterior Clinton process on double side as B (right) and B1 (left). And the point of alas minor ossis sphenoridalis with sohenoidal creast was marked as point O. For the latter can not been distinguished in images, point O was used to replace the anterior nasal spine, which can accurately locate the median sagittal plane. The result of three-dimensional reconstruction is used to measure the distance between O and A, A1, B, B1 and angles between OA, OA1, OB, OB1 and their projection line on the standard horizontal plane (α, α1, β, β1). Analyzing the difference by examining the significance difference between both sides can also help the authors to determine whether there is a symmetric difference.

RESULTS

The distance of OA was measured as 23.2 (6.5) mm [range, 11.2-45.2 mm; 95% confidence interval (CI), 21.9-24.4 mm]. The distance of OA1 was measured as 23.4 (5.7) mm (range, 9.9-47.2 mm; 95% CI, 22.2-24.6 mm). The distance of OB was measured as 31.1 (5.5) mm (range, 17.8-45.2 mm; 95% CI, 30.0-32.2 mm). The distance of OB1 was measured as 31.2 (6.0) mm (range, 10.1-47.8 mm; 95% CI, 30.0-32.5 mm). The angle of α was measured as 81.1 (10.0)° (range, 60-137.5°, 95% CI, 79.0-83.2°). The angle of α1 was measured as 81.3 (8.5)° (range, 60-97.4°, 95% CI, 79.5-83.1°). The angle of β was measured as 91.5 (5.2)° (range, 74.9-102.2°, 95% CI, 90.5-92.6°). The angle of β1 was measured as 91.0 (6.6)° (range, 74.7-104.7°, 95% CI, 89.2-92.0°).

CONCLUSIONS

The above results can facilitate the location of these structures and minimize surgical trauma to optic chiasm and carotid artery surrounding. The method is especially effective in promising more secure and accurate direction to guide surgeons during surgeries in pituitary adenomas.

Communicating Hydrocephalus Associated with Small- to Medium-Sized Vestibular Schwannomas: Clinical Significance of the Tumor Apparent Diffusion Coefficient Map

BACKGROUND

The etiology of hydrocephalus associated with the small- to medium-sized vestibular schwannomas is still controversial. We investigated tumor-specific factors related to the association of hydrocephalus with small- to medium-sized vestibular schwannomas.

METHODS

Among the 77 patients with vestibular schwannoma smaller than 30 mm, 9 patients demonstrated associated communicating hydrocephalus. Patient medical records, radiologic data, and histopathologic specimens were reviewed retrospectively. The age of the patients, and size, mean apparent diffusion coefficient (ADC) value, and histologic features of the tumors were compared with those of patients without hydrocephalus.

RESULTS

The symptoms related to hydrocephalus improved in all patients after tumor removal. Both the mean size and ADC values exhibited a statistically significant difference between the tumors with and without hydrocephalus (P < 0.01).

CONCLUSIONS

The size and ADC value of the tumor were significantly related to the association with hydrocephalus. The increased tumor ADC value was considered to be the result of degenerative change and suggested the involvement of protein sloughing in the etiology of the associated hydrocephalus.

Facial Nerve Outcome after Vestibular Schwannoma Resection: A Comparative Meta-Analysis of Endoscopic versus Open Retrosigmoid Approach

The minimal access retrosigmoid endoscopic approach to vestibular schwannoma (VS) resection has been used with promising results. However, it has not been compared with the standard open approach in the literature. We performed a meta-analysis review for all articles describing both approaches for VS from 1996 to 2011. We found 1861 articles. After review and discussion, we narrowed our study to 25 articles, 4 endoscopic and 21 open. The total number of patients was 3026 for open and 790 for endoscopic. The mean tumor sizes in the open and endoscopic series were 2.5 cm and 2.7 cm, respectively. Good facial nerve outcome was achieved in 67% of the open series patients and in 94% of the endoscopic series patients. Other outcomes in the open and endoscopic series were the following: gross total resection, 91% versus 97%; functional hearing, 22.6% versus 46%; wound infection, 1.3% versus 2.6%; and recurrence, 5.4% versus 2.2%. We acknowledge the limitations of our study, but we can state that the endoscopic approach is not inferior to the standard open approach. In expert hands the endoscopic approach can offer as good a result as the open, with potential benefits such as less pain and a shorter length of stay in the hospital. There is a need for more controlled studies for a definitive comparison.

[Treatment of giant acoustic neuromas]

INTRODUCTION AND OBJECTIVES

To analyze the treatment modality and outcome of a series of patients with giant acoustic neuromas, a particular type of tumour characterised by their size (extracanalicular diameter of 4cm or more) and high morbidity and mortality.

MATERIALS AND METHODS

This was a retrospective unicentre study of patients with acoustic neuromas treated in a period of 12 years. In our institutional series of 108 acoustic neuromas operated on during that period, we found 13 (12%) cases of giant acoustic neuromas. We reviewed the available data of these cases, including presentation and several clinical, anatomical, and microsurgical aspects.

RESULTS

All patients were operated on by the same neurosurgeon and senior author (EU) using the suboccipital retrosigmoid approach and complete microsurgical removal was achieved in 10 cases. In one case, near total removal was deliberately performed, in another case a CSF shunt was placed as the sole treatment measure, and in the remaining case no direct treatment was given. One patient died in the immediate postoperative period. One year after surgery, 4 patients showed facial nerve function of iii or more in the House-Brackman scale.

CONCLUSIONS

The 4 most important prognostic characteristics of giant acoustic neuromas are size, adhesion to surrounding structures, consistency and vascularity. Only the first of these is evident in neuroimaging. Giant acoustic neuromas are characterised by high morbidity at presentation as well as after treatment. Nevertheless, the objective of complete microsurgical removal with preservation of cranial nerve function is attainable in some cases through the suboccipital retrosigmoid approach.

The Pseudotumor Cerebri Syndrome: A Unifying Pathophysiological Concept for Patients with Isolated Intracranial Hypertension with Neither Mass Lesion Nor Ventriculomegaly

In 1991 we proposed that while the syndrome of isolated intracranial hypertension might have many definite and probable causes, it has nonetheless a single unifying pathophysiological mechanism: namely, impairment of cerebrospinal fluid (CSF) reabsorption. For that reason, we also proposed then that it is best described by a single, unifying, inclusive term, namely, pseudotumor cerebri syndrome. Although it appears that there is, as far as nomenclature is concerned, now international agreement, there is as yet no agreement on pathophysiology and classification. Herein we outline our views on these matters and give our reasons.

Retrograde third ventriculocisternostomy from the posterior fossa

BACKGROUND

Postoperative hydrocephalus is common in patients after resection of a posterior fossa tumor, with as many as 25% of patients requiring permanent cerebrospinal fluid diversion in the form of ventricular shunting or ventriculocisternostomy in some series. Prophylactic ventriculocisternostomy has been described with success in this patient population to prevent postoperative hydrocephalus.

OBJECTIVE

To define the technique of microsurgical retrograde third ventriculostomy from the posterior fossa.

METHODS

The operative technique is described and a single patient with 4-year follow-up is reported.

RESULTS

We describe the case of a 32-year-old woman who presented with a large cerebellopontine angle epidermoid tumor. She underwent a simultaneous lesion resection and third ventriculocisternostomy by accessing the interpeduncular cistern via a suboccipital posterior fossa approach and then making an incision through the tuber cinereum to access the third ventricle under direct vision.

CONCLUSION

Retrograde third ventriculostomy may be useful in the surgical treatment of patients already undergoing operations for large posterior fossa lesions who have a high likelihood of requiring permanent cerebrospinal fluid diversion and in whom exposure of the interpeduncular cistern is available.

Hydrocephalus associated with vestibular schwannomas: perioperative changes in cerebrospinal fluid

BACKGROUND

Cerebrospinal fluid (CSF) protein levels are known to increase in patients with vestibular schwannomas (VS) with concomitant hydrocephalus, however the only information available on perioperative changes in CSF in these patients comes from case reports. Here, we investigated the relation between CSF protein and hydrocephalus in a large series of patients undergoing resection of VS.

METHOD

We classified 376 patients undergoing resection for VS at our institute into two groups, namely VS and no hydrocephalus (control, n = 319) and VS with concomitant hydrocephalus (n = 57), and compared clinical parameters. Among the 57 patients diagnosed with hydrocephalus, hydrocephalus status was examined by lumbar puncture in 20 patients with communicative hydrocephalus, and pre- and postoperative scores in CSF properties were compared.

RESULTS

Patients in the hydrocephalus group were significantly older than those in the control group (mean, 55.8 vs. 43.8 years), and had a longer disease duration (median, 76 vs. 12 months), larger tumors (median, 15.6 vs. 5.5 ml), and a higher protein concentration in CSF (median, 147.3 vs. 65.1 mg/dl). Perioperative CSF samples of hydrocephalus patients showed a significantly decrease in cerebrospinal pressure after tumor removal (median, -75mmH2O), followed by a decrease in CSF protein (median, -74.5 mg/dl). No patients required the placement of a shunt.

CONCLUSIONS

Extended disease duration and elevated CSF protein secondary to the presence of a tumor contribute to the occurrence of hydrocephalus. Primary maximal tumor removal for VS with coexisting hydrocephalus avoids an unnecessary shunt.

Communicating hydrocephalus and vestibular schwannomas: etiology, treatment, and long-term follow-up

Background Large vestibular schwannomas (VSs) can cause hydrocephalus by obstructing the fourth ventricle. Little is known about the communicating hydrocephalus that is seen with a smaller VS. Methods The clinicopathological findings and follow up of three patients with communicating hydrocephalus associated with a small VS are presented. Results Four patients aged 40 to 66 years (mean: 57.7) presented with ataxia, dementia, and urinary incontinence. The VS were 2.0 to 2.4 cm. The cerebrospinal fluid (CSF) protein was elevated in three patients in whom it was measured (1.7 to 6 times normal). The VS was resected in two patients. All of the patients required ventriculoperitoneal shunting (VPS). All of the patients were asymptomatic or improved at follow-up at 9 months to 13 years. Conclusion Communicating hydrocephalus associated with a VS can occur in younger patients than was previously thought. An elevated CSF protein appears to be important, but other factors may be involved. A shunting procedure is often required to relieve the symptoms of hydrocephalus even if the tumor is resected. Possible etiological causes of communicating hydrocephalus in patients with a small VS are discussed.

Technical nuances of resection of giant (> 5 cm) vestibular schwannomas: pearls for success

Removal of vestibular schwannomas (VSs, or acoustic neuromas) remains one of the most challenging operations in neurosurgery. Giant or huge tumors (> 5 cm) heighten these challenges, and technical nuances play a special role in maximizing tumor resection while minimizing complications. In this article, the senior author describes his technical experience with microsurgical excision of giant VSs. The accompanying video further illustrates these details.