Cerebellopontine angle meningiomas: postoperative outcomes in a modern cohort

Creeping through the cranium: A rare and interesting presentation of a meningioma

A meningioma is a rare primary CNS tumor that tends to present more so in females in a slowly progressive fashion. The cavernous sinus and cerebellopontine angle are uncommon locations for meningiomas. We present a case of a meningioma in a 60-year-old female presenting to the emergency department for a sudden onset headache, vertigo, facial paresthesias, and chest pain. Inpatient workup revealed orthostatic hypotension, a meningioma spanning from the left cavernous sinus to the left cerebellopontine angle encasing the left cavernous internal carotid artery on MRI and CTA, and an incidental 12 mm calcified fibroadenoma on CT. Hospital course consisted of supportive treatment, physical rehabilitation, and review of previous imaging to determine need for intervention per consultants' recommendations. The patient was discharged with an antiplatelet, an antihistamine, appropriate additional medications, a vestibular therapy script, and outpatient referrals for a decision regarding surveillance and intervention. Overall, this case describes some key points. It demonstrates that cavernous sinus and cerebellopontine angle meningiomas can occur simultaneously, especially as a continuous mass, which very few cases have done so far. It also highlights an acute clinical presentation of a meningioma, contrary to the gradually progressive one observed in most instances. Last, but not least, it shows how nonspecific symptoms can lead to unique findings at times.

Unexpected recovery from complete deafness to normal hearing post surgical excision of a cerebellopontine angle meningioma: A case report

Background

Cerebellopontine angle (CPA) meningioma presents a significant management challenge due to its intricate relationship with the brainstem neurovascular bundles. The emphasis in the past has been on facial nerve preservation, but the current management standard is hearing preservation in patients with serviceable hearing; however, hearing restoration after complete loss is rare. We report an elderly man who had restoration of hearing in the right ear after complete loss following tumor resection through the retrosigmoid route.

Case Description

A 73-year-old male patient presented with progressive hearing impairment in the right ear, culminating in hearing loss for about 2 months (the American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] class D). He also had mild cerebellar symptoms, but other cranial nerves and long tracts were normal. Brain magnetic resonance imaging confirmed a right CPA meningioma, and he had tumor resection through the retrosigmoid route using meticulous microsurgical technique with vestibulocochlear nerve preservation, facial nerve monitoring, and intraoperative video angiography. He had restoration of hearing on follow-up (the American Academy of Otolaryngology-Head and Neck Surgery class A). Histology confirmed World Health Organization central nervous system grade 1 meningioma.

Conclusion

This case illustrates that hearing restoration is possible after complete loss in patients with CPA meningioma. We advocate hearing preservation surgery even in patients with non-serviceable hearing, as the chance of hearing recovery is possible.

The otologic approach in the management of posterior petrous surface meningiomas

PURPOSE

Report our experience in the management of posterior petrous surface meningiomas (PPSMs), and identify features that affect hearing, facial nerve (FN) function, and control of the disease.

METHODS

Retrospective case series of 131 patients surgically managed for PPSMs. FN status, hearing and tumour radicality were assessed and compared between patients with tumours of different locations (Desgeorges classification) and internal auditory canal involvement (IAC).

RESULTS

At the time of surgery 74.8% of patients had a hearing loss. Hearing was mostly unserviceable in tumors attached to the meatus. Pure tone audiometry did not correlate to IAC extension, while speech discrimination scores were statistically worse when the tumor occupied the IAC (unpaired t test, p = 0.0152). Similarly, extrameatal tumors undergoing removal by otic preserving techniques maintained postoperative hearing, whereas hearing worsened significantly in tumors involving the IAC (paired t test, p = 0.048). The FN was affected preoperatively in 11.4% of cases. Postoperative FN palsy was significantly correlated to the IAC involvement (Fisher's exact test, p = 0.0013), while it was not correlated to tumor size. According to the Desgeorges classification, a postoperative FN palsy complicated the majority of anteriorly extending tumors and, two-fifths of meatus centred tumors. 75% of posterior located tumors had a postoperative FN grade I HB.

CONCLUSIONS

Since the involvement of the IAC by the tumor affects both hearing and FN function, the IAC is of primary importance in PPSMs and should be studied and addressed as much as the tumor location in the CPA.

Unusual imaging characteristics of cystic meningioma in cerebellopontine angle

We report a case of cystic meningioma at the left cerebellopontine angle (CPA). Magnetic resonance imaging demonstrated both solid and cystic components in the tumor. The cystic component appeared slightly hyperintense compared to cerebrospinal fluid on fluid-attenuated inversion recovery (FLAIR) imaging. A hypointense tubular structure was identified in the cystic component on 3D driven equilibrium sequencing. These imaging findings are unusual for cystic meningioma. However, awareness of these unusual imaging features is important to determine appropriate treatment strategies although cystic meningioma at the CPA is extremely rare.

Effect of Household Income on Short-Term Outcomes Following Cerebellopontine Angle Tumor Resection

Objectives  The objective of this study is to elucidate the impact of income on short-term outcomes in a cerebellopontine angle (CPA) tumor resection population. Design  This is a retrospective regression analysis. Setting  This study was done at a single, multihospital, urban academic medical center. Participants  Over 6 years (from June 7, 2013, to April 24, 2019), 277 consecutive CPA tumor cases were reviewed. Main Outcome Measures  Outcomes studied included readmission, emergency department evaluation, unplanned return to surgery, return to surgery after index admission, and mortality. Univariate analysis was conducted among the entire population with significance set at a p -value <0.05. The population was divided into quartiles based on median household income and univariate analysis conducted between the lowest (quartile 1 [Q1]) and highest (quartile 4 [Q4]) socioeconomic quartiles, with significance set at a p -value <0.05. Stepwise regression was conducted to determine the correlations among study variables and to identify confounding factors. Results  Regression analysis of 273 patients demonstrated decreased rates of unplanned reoperation ( p  = 0.015) and reoperation after index admission ( p  = 0.035) at 30 days with higher standardized income. Logistic regression between the lowest (Q1) and highest (Q4) socioeconomic quartiles demonstrated decreased unplanned reoperation ( p  = 0.045) and decreasing but not significant reoperation after index admission ( p  = 0.15) for Q4 patients. No significant difference was observed for other metrics of morbidity and mortality. Conclusion  Higher socioeconomic status is associated with decreased risk of unplanned reoperation following CPA tumor resection.

Identification and Management of Aggressive Meningiomas

Meningiomas are common primary central nervous system tumors derived from the meninges, with management most frequently entailing serial monitoring or a combination of surgery and/or radiation therapy. Although often considered benign lesions, meningiomas can not only be surgically inaccessible but also exhibit aggressive growth and recurrence. In such cases, adjuvant radiation and systemic therapy may be required for tumor control. In this review, we briefly describe the current WHO grading scale for meningioma and provide demonstrative cases of treatment-resistant meningiomas. We also summarize frequently observed molecular abnormalities and their correlation with intracranial location and recurrence rate. We then describe how genetic and epigenetic features might supplement or even replace histopathologic features for improved identification of aggressive lesions. Finally, we describe the role of surgery, radiotherapy, and ongoing systemic therapy as well as precision medicine clinical trials for the treatment of recurrent meningioma.

Factors Associated With Abducens Nerve Palsy in Patients Undergoing Surgery for Petroclival Meningiomas

BACKGROUND

During the surgical resection of petroclival meningiomas, preserving the cranial nerves is crucial. The abducens nerve is particularly vulnerable during surgery. However, the preoperative risk factors and postoperative prognosis of abducens nerve palsy (ANP) are poorly understood.

METHODS

We retrospectively analyzed 70 patients who underwent surgery for petroclival meningiomas between May 2010 and December 2019, divided into gross-total resection (GTR) and subtotal resection (STR) groups. The relationship of preoperative clinical factors with the incidence and recovery of postoperative ANP was analyzed.

RESULTS

Postoperative ANP was observed in 23 patients (32.9%). Multivariable logistic regression revealed that the tumor-to-cerebellar peduncle T2 imaging intensity index (TCTI) (P < 0.001) and internal auditory canal invasion (P = 0.033) contributed to postoperative ANP. GTR was achieved in 37 patients (52.9%), and 10 (27.0%) of them showed ANP. STR was achieved in 33 patients (47.1%), and 13 (39.4%) of them showed ANP. Recovery from ANP took a median of 6.6 months (range, 4.5-20.3 months). At 6 months after the operation, recovery of the abducens nerve function was observed in 16 patients (69.0%); of whom, 4 (40.0%) were in the GTR group and 12 (92.3%) were in the STR group (P = 0.025).

CONCLUSIONS

TCTI and internal auditory canal invasion were the risk factors for postoperative ANP. Although intentional STR did not prevent ANP immediately after the operation, recovery of the abducens nerve function after surgery was observed more frequently in the STR group than in the GTR group.

Predictors of hearing functional outcome following surgery for cerebellopontine angle meningioma

OBJECTIVE

Cerebellopontine angle (CPA) meningiomas can affect hearing function and require expeditious treatment to prevent permanent hearing loss. The authors sought to determine the factors associated with functional hearing outcome in CPA meningioma patients treated with surgery and/or radiation therapy in the form of either stereotactic radiosurgery or stereotactic radiation therapy.

METHODS

Consecutive patients with CPA meningiomas who had presented at our hospital from 2008 to 2018 were identified through retrospective chart review. Hearing function (as defined by pure tone average (PTA) and speech discrimination score (SDS) on Audiogram) was assessed before and after surgery for CPA meningioma. Audiograms with PTA > 50 dB and SDS < 69% were defined as poor hearing functional outcome. Multivariable Cox Proportional Hazards Regression Model was used to assess the associations between pre-operative hearing functional assessment and post-operative hearing functional outcomes.

RESULTS

The study cohort included 31 patients (80.6% females, with a mean age of 61.3 ± 15.2 years) with a median clinical follow-up of 5 months (range: 1 week-98 months). The mean pre-operative PTA and SDS were 23.8 ± 11.2 dB and 64.4 ± 22.2% respectively. At the last visit, there was significant hearing recovery, with an improvement of 29.7 ± 18.0 dB (p < 0.001) and 87.6 ± 17.8% (p < 0.001) in PTA and SDS respectively. After adjusting for age, gender, tumor volume, location, and tumor classification, Multivariable Cox Proportional Hazards Regression Model was conducted which revealed that patients undergoing surgery through retro sigmoid approach [Hazards Ratio (HR): 32.1, 95% Confidence Interval (CI): 2.11-491.0, p = 0.01] and gross total resection (GTR) (HR: 2.99, 95% CI: 1.09-9.32, p = 0.05) had significantly higher risk of poor hearing functional outcome compared to petrosal approach and near/subtotal resection. Moreover, patients with poor preoperative hearing had 85% higher chance of poor hearing functional outcome postoperatively (HR: 0.15, 95%CI: 0.03-0.59, p = 0.007).

CONCLUSION

Postoperative improvement in hearing is a reasonable expectation following surgery for CPA meningioma. Preoperative hearing, surgical approach and extent of surgical resection are predictive factors of postoperative hearing function outcome and can therefore aid in identification of patients at higher risk of hearing loss.

Facial pain and sensory outcomes following resection of tumors compressing the trigeminal nerve

OBJECTIVE

Tumors compressing the trigeminal nerve can cause facial pain, numbness, or paresthesias. Limited data exist describing how these symptoms change after resection and what factors predict symptom improvement. The objective of this study was to report trigeminal pain and sensory outcomes after tumor resection and identify factors predicting postoperative symptom improvement.

METHODS

This retrospective study included patients with tumors causing facial pain, numbness, or paresthesias who underwent resection. Trigeminal schwannomas were excluded. Logistic regression, recursive partitioning, and time-to-event analyses were used to report outcomes and identify variables associated with facial sensory outcomes.

RESULTS

Eighty-six patients met inclusion criteria, and the median follow-up was 3.1 years; 63 patients (73%) had meningiomas and 23 (27%) had vestibular schwannomas (VSs). Meningioma patients presented with pain, numbness, and paresthesias in 56%, 76%, and 25% of cases, respectively, compared with 9%, 91%, and 39%, respectively, for patients with VS. Most meningioma patients had symptoms for less than 1 year (60%), whereas the majority of VS patients had symptoms for 1-5 years (59%). The median meningioma and VS diameters were 3.0 and 3.4 cm, respectively. For patients with meningiomas, gross-total resection (GTR) was achieved in 27% of patients, near-total resection (NTR) in 29%, and subtotal resection (STR) in 44%. For patients with VS, GTR was achieved in 9%, NTR in 30%, and STR in 61%. Pain improved immediately after tumor resection in 81% of patients and in 92% of patients by 6 weeks. Paresthesias improved immediately in 80% of patients, increasing to 84% by 6 weeks. Numbness improved more slowly, with 52% of patients improving immediately, increasing to 79% by 2 years. Pain recurred in 22% of patients with meningiomas and 0% of patients with VSs. After resection, the Barrow Neurological Institute (BNI) facial pain intensity score improved in 73% of patients. The tumor diameter significantly predicted improvement in BNI score (OR 0.47/cm larger, 95% CI 0.22-0.99; p = 0.047). Complete decompression of the trigeminal nerve was associated with qualitative improvement in pain (p = 0.037) and decreased pain recurrence (OR 0.08, 95% CI 0.01-0.67; p = 0.024).

CONCLUSIONS

Most patients with facial sensory symptoms caused by meningiomas or VSs experienced improvement after resection. Surgery led to immediate and sustained improvement in pain and paresthesias, whereas numbness was slower to improve. Patients with smaller tumors and complete decompression of the trigeminal nerve were more likely to experience improvement in facial pain.

Deadly complication of sacrificing superior petrosal vein during cerebellopontine angle tumor resection: A case report and literature review

Background:

Tumors of the cerebellopontine angle (CPA) are challenging to resect and have been proven difficult for neurosurgeons to manage optimally. Superior petrosal vein complex (SPVC) as the main drainage system and close proximity to CPA could be an obstacle during operation. There is an incidence ranging from 55% to 84% of injury to one part of the SPVC during CPA tumor surgery.

Case Description:

We report a case of 65-year-old woman with CPA tumor, who complained of unilateral hearing loss, dizziness, and facial pain. During tumor resection, one part of SPV complex was injured, then cerebellar edema develops.

Conclusion:

This case provides an overview of surgical complication associated with venous sacrifice. This would support the agreement to preserve SPV regarding risks and improve the quality of surgical decision making.

Sensitivity and Negative Predictive Value of Motor Evoked Potentials of the Facial Nerve

OBJECTIVE

 The objective of this study was to determine the performance of the standard alarm criterion of motor evoked potentials (MEPs) of the facial nerve in surgeries performed for resections of vestibular schwannomas or of other lesions of the cerebellopontine angle.

METHODS

 This retrospective study included 33 patients (16 with vestibular schwannomas and 17 with other lesions) who underwent the resection surgery with transcranial MEPs of the facial nerve. A reproducible 50% decrease in MEP amplitude, resistant to a 10% increase in stimulation intensity, was applied as the alarm criterion during surgery. Facial muscular function was clinically evaluated with the House-Brackmann score (HBS), pre- and postsurgery at 3 months.

RESULTS

 In the patient group with vestibular schwannoma, postoperatively, the highest sensitivity and negative predictive values were found for a 30% decrease in MEP amplitude, that is, a criterion stricter than the 50% decrease in MEP amplitude criterion, prone to trigger more warnings, used intraoperatively. With this new criterion, the sensitivity would be 88.9% and the negative predictive value would be 85.7%. In the patient group with other lesions of the cerebellopontine angle, the highest sensitivity and negative predictive values were found equally for 50, 60, or 70% decrease in MEP amplitude. With these criteria, the sensitivities and the negative predictive values would be 100.0%.

CONCLUSION

 Different alarm criteria were found for surgeries for vestibular schwannomas and for other lesions of the cerebellopontine angle. The study consolidates the stricter alarm criterion, that is, a criterion prone to trigger early warnings, as found previously by others for vestibular schwannoma surgeries (30% decrease in MEP amplitude).

The role of socioeconomic status on outcomes following cerebellopontine angle tumor resection

PURPOSE

It is well documented that the interaction between many social factors can affect clinical outcomes. However, the independent effects of economics on outcomes following surgery are not well understood. The goal of this study is to investigate the role socioeconomic status has on postoperative outcomes in a cerebellopontine angle (CPA) tumor resection population.

MATERIALS AND METHODS

Over 6 years (07 June 2013 to 24 April 2019), 277 consecutive CPA tumor cases were reviewed at a single, multihospital academic medical center. Patient characteristics obtained included median household income, Charlson Comorbidity Index (CCI), race, BMI, tobacco use, amongst 23 others. Outcomes studied included readmission, ED evaluation, unplanned return to surgery (during and after index admission), return to surgery after index admission, and mortality within 90 days, in addition to reoperation and mortality throughout the entire follow-up period. Univariate analysis was conducted amongst the entire population with significance set at a p value <0.05. The population was divided into quartiles based on median household income and univariate analysis conducted between the lowest (Q1) and highest (Q4) socioeconomic quartiles, with significance set at a p value <0.05. Stepwise regression was conducted to determine the correlations amongst study variables and identify confounding factors.

RESULTS

Regression analysis of 273 patients did not find household income to be associated with any of the long-term outcomes assessed. Similarly, a Q1 vs Q4 comparison did not yield significantly different odds of outcomes assessed.

CONCLUSION

Although not statistically significant, the odds ratios suggest socioeconomic status may have a clinically significant effect on postsurgical outcomes. Further studies in larger, matched populations are necessary to validate these findings.

Using the Post-Descendens Hypoglossal Nerve in Hypoglossal-Facial Anastomosis: An Anatomic and Histologic Feasibility Study

BACKGROUND

Hypoglossal-facial anastomosis (HFA) is a popular facial reanimation technique. Mobilizing the intratemporal segment of the facial nerve and using the post-descendens hypoglossal nerve (ie, the segment distal to the take-off of descendens hypoglossi) have been proposed to improve results. However, no anatomic study has verified the feasibility of this technique.

OBJECTIVE

To assess the anatomic feasibility of HFA and the structural compatibility between the 2 nerves when the intratemporal facial and post-descendens hypoglossal nerves are used.

METHODS

The facial and hypoglossal nerves were exposed bilaterally in 10 sides of 5 cadaveric heads. The feasibility of a side-to-end (ie, partial end-to-end) HFA with partial sectioning of the post-descendens hypoglossal nerve and the mobilized intratemporal facial nerve was assessed. The axonal count and cross-sectional area of the facial and hypoglossal nerves at the point of anastomosis were assessed.

RESULTS

The HFA was feasible in all specimens with a mean (standard deviation) 9.3 (5.5) mm of extra length on the facial nerve. The axonal counts and cross-sectional areas of the hypoglossal and facial nerves matched well. Considering the reduction in the facial nerve cross-sectional area after paralysis, the post-descendens hypoglossal nerve can provide adequate axonal count and area to accommodate the facial nerve stump.

CONCLUSION

Using the post-descendens hypoglossal nerve for side-to-end anastomosis with the mobilized intratemporal facial nerve is anatomically feasible and provides adequate axonal count for facial reanimation. When compared with use of the pre-descendens hypoglossal nerve, this technique preserves C1 fibers and has a potential to reduce glottic complications.

Petrous face meningiomas

Cerebellopontine angle (CPA) meningiomas arise from the petrous face of the temporal bone, which forms the lateral boundary of the CPA. They can be categorized into anterior, middle, and posterior, based on their attachment in relation to the internal acoustic meatus. Each of them presents with their own characteristic clinical syndromes. Because of their close proximity to neurovascular structures, they pose a challenge during surgery. Microsurgery remains the primary treatment modality for large and symptomatic meningiomas. The retrosigmoid approach provides an ideal access for most of the tumors in this location. Radiosurgery is the primary modality of adjuvant therapy for residual, recurrent, and small lesions. Fully fractionated external beam radiotherapy can be used for larger, broader-based residual/recurrent tumors. Management of these complex lesions should include patient preferences and a team approach, including a skull base neurosurgeon, neurotologist, and radiation oncologist.

Hearing preservation after Gamma Knife radiosurgery for cerebellopontine angle meningiomas

OBJECTIVE

The objective of this study was to assess hearing function after Gamma Knife treatment of cerebellopontine angle (CPA) meningiomas and assess factors affecting hearing outcome. Additionally, the authors opted to compare these results with those after Gamma Knife treatment of vestibular schwannomas (VSs), because most of the information on hearing outcome after stereotactic radiosurgery (SRS) comes from reports on VS treatment. Hearing preservation, to the best of the authors’ knowledge, has never been separately addressed in studies involving Gamma Knife radiosurgery (GKRS) for CPA meningiomas.

METHODS

This study included all patients who underwent a single session of GKRS between 2002 and 2014. The patients were divided into two groups. Group A included 66 patients with CPA meningiomas with serviceable hearing and tumor extension into the region centered on the internal auditory meatus. Group B included 144 patients with VSs with serviceable hearing. All patients had serviceable hearing before treatment (Gardner-Robertson [GR] Grades I and II). The median prescription dose was 12 Gy (range 10–12 Gy) in both groups. The median follow-up of groups A and B was 42 months (range 6–149 months) and 49 months (range 6–149 months), respectively.

RESULTS

At the last follow-up, the tumor control rate was 97% and 94% in groups A and B, respectively. Hearing preservation was defined as maintained serviceable hearing according to GR hearing score. The hearing preservation rate was 98% and 66% and the 7-year actuarial serviceable hearing preservation rate was 75% and 56%, respectively, between both groups. In group A, the median maximum cochlear dose in the patients with stable and worsened hearing grade was 6.3 Gy and 5.5 Gy, respectively. In group B, factors affecting hearing preservation were cochlear dose ≤ 7 Gy, follow-up duration, and tumor control. The only determinant of hearing preservation between both groups was tumor type.

CONCLUSIONS

GKRS for CPA meningiomas provides excellent hearing preservation in addition to high tumor control rate. Hearing outcome is better with CPA meningiomas than with VSs. Further long-term prospective studies on determinants of hearing outcome after GKRS for CPA meningiomas should be conducted.

Petrous Face Meningiomas: Classification, Clinical Syndromes, and Surgical Outcomes

BACKGROUND

Petrous face meningiomas (PFMs) are challenging tumors because of their proximity to the cranial nerves, brainstem, and critical vasculature. The objective of this study is to present surgical outcomes and support an anatomic classification for PFM based on clinical presentation.

METHODS

A retrospective chart review was performed, and 51 PFMs were identified. Tumors were classified by location along the petrous face into anterior, middle, and posterior. Presentation and outcomes were analyzed with logistic regression.

RESULTS

The median follow-up was 31.6 months. Tumors were World Health Organization grade I (n = 50), with 1 World Health Organization grade II tumor. Location was anterior (22%), middle (14%), posterior (53%), and overlapping (12%). Median tumor diameter was 3.0 cm (range, 0.8-6.2 cm). Anterior location was associated with facial pain/numbness on presentation (P < 0.0001), middle location with hearing loss/vestibular dysfunction (P = 0.0035), and posterior with hydrocephalus (P = 0.0190), headache (P = 0.0039), and vertigo (P = 0.0265). Extent of resection was gross total (63%), near total (14%), and subtotal (25%). The observed radiographic recurrence rate was 15%. Mean progression-free survival after diagnosis was 9.1 years with 2-year, 5-year, and 10-year progression-free survival of 91.8%, 78.6%, and 62.9%, respectively. The complication rate was 27%. Age, location, and approach were not associated with complications.

CONCLUSIONS

PFMs present with distinct clinical syndromes based on their location along the petrous face: anterior with trigeminal symptoms, middle with auditory/vestibular symptoms, and posterior with symptoms of mass effect/hydrocephalous. Surgical resection is associated with excellent long-term survival and a low rate of recurrence, which can be managed with radiotherapy.

Profound hearing loss following surgery in pediatric patients with posterior fossa low-grade glioma

Background

Hearing loss may occur in patients with posterior fossa low-grade glioma who undergo surgery.

Methods

We retrospectively reviewed 217 patients with posterior fossa low-grade glioma, including 115 for whom results of hearing tests performed after surgery and before chemotherapy or radiation therapy were available. We explored the association of UHL with age at diagnosis, sex, race, tumor location, extent of resection, posterior fossa syndrome, ventriculoperitoneal shunt placement, and histology.

Results

Of the 115 patients, 15 (13.0%: 11 male, 6 black, 8 white, 1 multiracial; median age 7 years [range, 1.3-17.2 years]) had profound UHL after surgery alone or before receiving ototoxic therapy. Median age at tumor diagnosis was 6.8 years (range, 0.7-14.1 years), and median age at surgery was 6.8 years (range, 0.7-14.1 years). Patients with UHL had pathology characteristic of pilocytic astrocytoma (n = 10), ganglioglioma (n = 4), or low-grade astrocytoma (n = 1). Of these 15 patients, 4 underwent biopsy, 1 underwent gross total resection, 1 underwent near-total resection, and 9 underwent subtotal resection. UHL was more frequent in black patients than in white patients (OR 7.3, P = .007) and less frequent in patients who underwent gross total resection or near-total resection than in those who underwent subtotal resection (OR 0.11, P = .02).

Conclusions

Children undergoing surgery for posterior fossa low-grade glioma are at risk for UHL, which may be related to race or extent of resection. These patients should receive postoperative audiologic testing, as earlier intervention may improve outcomes.

Clinical Features and Surgical Outcomes in Patients with Cerebellopontine Angle Hemangioblastomas: Retrospective Series of 23 Cases

OBJECTIVES

Hemangioblastomas in the cerebellopontine angle (CPA) are uncommon and have rarely been reported. They may be easily misdiagnosed because of the atypical location and clinical and imaging features. The present study aimed to characterize clinical and radiologic features, treatment strategies, and outcomes in these rare lesions and to investigate various factors that may affect postoperative outcomes.

METHODS

The medical records of patients with CPA hemangioblastomas who underwent surgery from 2003-2016 at the West China Hospital were reviewed retrospectively and statistically analyzed.

RESULTS

Twenty-three patients (14 males and 9 females) presented with CPA hemangioblastomas. Eight patients (34.8%) had von Hippel-Lindau (VHL) syndrome. Gross total resection was achieved in 22 patients (95.6%). The mean follow-up was 45.1 ± 36.2 months (range 3-144 months). After surgery, the symptoms improved in 18 cases (78.3%), remained unchanged in 3 cases (13%), and were aggravated in 2 cases (8.7%). Four patients showed local recurrence during follow-up (17.4%). Patients with cystic hemangioblastomas had a better neurologic improvement (P = 0.041) compared with patients with solid tumors. Furthermore, patients with maximal diameter of tumors >3 cm (P = 0.035) or solid tumors (P = 0.018) showed a higher incidence of postoperative complications. The local recurrence was correlated with VHL disease (P = 0.027).

CONCLUSIONS

Although hemangioblastomas of the CPA are challenging lesions to treat surgically, they can be removed safely when these lesions are appropriately diagnosed and treated. Patients with VHL disease are more likely to have a local recurrence. A regular follow-up is recommended to detect the local and distant recurrence, even if the clinical course is benign and the tumor is totally resected.

Efficacy and outcomes of facial nerve-sparing treatment approach to cerebellopontine angle meningiomas

OBJECTIVE Advanced microsurgical techniques contribute to reduced morbidity and improved surgical management of meningiomas arising within the cerebellopontine angle (CPA). However, the goal of surgery has evolved to preserve the quality of the patient's life, even if it means leaving residual tumor. Concurrently, Gamma Knife radiosurgery (GKRS) has become an acceptable and effective treatment modality for newly diagnosed, recurrent, or progressive meningiomas of the CPA. The authors review their institutional experience with CPA meningiomas treated with GKRS, surgery, or a combination of surgery and GKRS. They specifically focus on rates of facial nerve preservation and characterize specific anatomical features of tumor location with respect to the internal auditory canal (IAC). METHODS Medical records of 76 patients with radiographic evidence or a postoperative diagnosis of CPA meningioma, treated by a single surgeon between 1992 and 2016, were retrospectively reviewed. Patients with CPA meningiomas smaller than 2.5 cm in greatest dimension were treated with GKRS, while patients with tumors 2.5 cm or larger underwent facial nerve-sparing microsurgical resection where appropriate. Various patient, clinical, and tumor data were gathered. Anatomical features of the tumor origin as seen on preoperative imaging confirmed by intraoperative investigation were evaluated for prognostic significance. Facial nerve preservation rates were evaluated. RESULTS According to our treatment paradigm, 51 (67.1%) patients underwent microsurgical resection and 25 (32.9%) patients underwent GKRS. Gross-total resection (GTR) was achieved in 34 (66.7%) patients, and subtotal resection (STR) in 17 (33.3%) patients. Tumors recurred in 12 (23.5%) patients initially treated surgically, requiring additional surgery and/or GKRS. Facial nerve function was unchanged or improved in 68 (89.5%) patients. Worsening facial nerve function occurred in 8 (10.5%) patients, all of whom had undergone microsurgical resection. Upfront treatment with GKRS for CPA meningiomas smaller than 2.5 cm was associated with preservation of facial nerve function in all patients over a median follow-up of 46 months, regardless of IAC invasion and tumor origin. Anatomical origin was associated with extent of resection but did not correlate with postoperative facial nerve function. Tumor size, extent of resection, and the presence of an arachnoid plane separating the tumor and the contents of the IAC were associated with postoperative facial nerve outcomes. CONCLUSIONS CPA meningiomas remain challenging lesions to treat, given their proximity to critical neurovascular structures. GKRS is a safe and effective option for managing CPA meningiomas smaller than 2.5 cm without associated mass effect or acute neurological symptoms. Maximal safe resection with preservation of neurological function can be performed for tumors 2.5 cm or larger without significant risk of facial nerve dysfunction, and, when combined with GKRS for recurrence and/or progression, provides excellent disease control. Anatomical features of the tumor origin offer critical insights for optimizing facial nerve preservation in this cohort.