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

Choroid plexus mast cells drive tumor-associated hydrocephalus

Tumor-associated hydrocephalus (TAH) is a common and lethal complication of brain metastases. Although other factors beyond mechanical obstructions have been suggested, the exact mechanisms are unknown. Using single-nucleus RNA sequencing and spatial transcriptomics, we find that a distinct population of mast cells locate in the choroid plexus and dramatically increase during TAH. Genetic fate tracing and intracranial mast-cell-specific tryptase knockout showed that choroid plexus mast cells (CPMCs) disrupt cilia of choroid plexus epithelia via the tryptase-PAR2-FoxJ1 pathway and consequently increase cerebrospinal fluid production. Mast cells are also found in the human choroid plexus. Levels of tryptase in cerebrospinal fluid are closely associated with clinical severity of TAH. BMS-262084, an inhibitor of tryptase, can cross the blood-brain barrier, inhibit TAH in vivo, and alleviate mast-cell-induced damage of epithelial cilia in a human pluripotent stem-cell-derived choroid plexus organoid model. Collectively, we uncover the function of CPMCs and provide an attractive therapy for TAH.

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.

Communicating Hydrocephalus Following Treatment of Cerebellopontine Angle Tumors

OBJECTIVE

This study aimed to clarify the risk of communicating hydrocephalus in cerebellopontine angle tumors, focusing on distinct tumor types and treatment modalities, i.e., tumor resection and stereotactic radiosurgery (SRS).

METHODS

This study was a retrospective single-center cohort study. The cumulative incidences of symptomatic communicating hydrocephalus in schwannoma and meningioma patients were evaluated. A multivariate Cox model was used to assess the hazard ratios for the risk factors and odds ratios of distinct treatment subgroups.

RESULTS

A total of 405 cases, including 286 schwannomas and 119 meningiomas, were retrospectively reviewed. The risk of hydrocephalus was significantly higher in schwannomas than that in meningiomas (hazard ratio, 4.70 [95% confidence interval, 1.78-12.4, P = 0.002]). Patients with schwannomas who received SRS without tumor resection showed a significantly higher incidence than meningioma cases: 10.6% versus 1.4% (P = 0.037). We identified specific subgroups that were prone to increase the risk of hydrocephalus when treated with SRS alone. The result showed that patients with vestibular schwannoma of Koos grade III had a greater benefit from tumor resection than from SRS in preventing hydrocephalus (odds ratio, 0.089 [95% confidence interval, 0.011-0.743, P = 0.025]).

CONCLUSIONS

Symptomatic communicating hydrocephalus is more frequent in schwannoma than that in meningiomas. Primary treatment with tumor resection lowers the risk of hydrocephalus in specific subgroups of vestibular schwannoma.

Cerebrospinal fluid shunt for normal pressure hydrocephalus patient exacerbates cord symptoms due to spinal tumor

Background

Normal-pressure hydrocephalus (NPH) and spinal intradural extramedullary benign tumors rarely exist together. Here, a 72-year-old female who presented with NPH symptoms (i.e., gait disturbance and dementia) newly developed symptoms of spinal cord compression attributed to a previously undiagnosed schwannoma.

Case Description

A 72-year-old female was diagnosed with NPH without disproportionately enlarged subarachnoid space hydrocephalus. The lumbar puncture revealed an elevated cerebrospinal fluid (CSF) protein level of 0.141 g/dl, but with normal pressure. The patient's NPH symptoms improved after lumbar-peritoneal shunt placement. However, a year later, she subacutely developed a progressive Brown-Sequard syndrome. On the cervical magnetic resonance (MR), an intradural extramedullary lesion was found at the C5-C6 level which at surgery, proved to be a schwannoma. A review of this patient and three others with NPH and intradural extramedullary benign tumors revealed that 4.3 months following CSF shunting for NPH, they developed rapidly progressive cord deficits, attributed to their benign spinal tumors.

Conclusion

Before the placement of shunts for NPH, patients should undergo holospinal MR imaging studies to rule out attendant spinal intradural extramedullary tumors.

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.

Comparison of a bolt-connected external ventricular drain with a tunneled external ventricular drain - a narrative review and meta-analysis

External ventricular drain (EVD) is one of the most commonly performed neurosurgical procedures. EVD can be associated with high rates of complications like misplacement, iatrogenic hemorrhage, and CSF infection. Several modifications have been proposed in the EVD insertion techniques to decrease the risk of these complications. Bolt-connected EVD, one of these modifications which involves insertion of a bolt in the burr hole, has been proposed to have better chances of optimal placement of EVD tip, lesser risk of CSF infection, and accidental pullout. A comprehensive search of different databases was performed to retrieve studies comparing the bolt-connected EVD with tunneled EVD and meta-analysis was done. Seven studies met inclusion criteria and were included in the meta-analysis. Our analysis revealed that bolt-connected EVD is associated with significantly better chances of optimal placement than traditional tunneled EVD (MH OR-1.65, 95% CI 1.14 to 2.40, p = 0.008). We also observed that bolt-connected EVD is associated with significantly decreased risk of CSF infection (MH OR-0.60, 95% CI 0.39 to 0.94, p = 0.026), EVD malfunction (MH OR-0.31, 95% CI 0.16 to 0.58, p = 0.0003), and accidental disconnection (MH OR-0.09, 95% CI 0.03 to 0.26, p < 0.0001) as compared to traditional tunneled EVD. The difference between the two techniques was not statistically significant for complications, multiple punctures done for insertion of EVD, iatrogenic intracranial, and need of reoperation. Bolt-connected external ventricular drain is associated with significantly more chances of optimal placement and lesser chances of accidental discontinuation and CSF infection than tunneled EVD. There was no statistically significant difference noted between the two techniques for multiple punctures done for insertion of EVD, iatrogenic intracranial hemorrhage and need of reoperation. However, most of the included studies were retrospective. Thus, the results from the meta-analysis should be interpreted with caution as further prospective high-quality studies are needed.

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.