Facial neuropathy in early postoperative period after resection of cerebellopontine angle tumor using various modalities of intraoperative neurophysiological monitoring: a systematic review and meta-analysis

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.

Objective To determine whether transcranial motor-evoked potential (TCMEP) monitoring of the facial nerve (FN) during cerebellopontine angle (CPA) tumor resection can predict both immediate and long-term postoperative FN function. Design Retrospective review. Setting Tertiary referral center. Main Outcome Measures DeltaTCMEP (final-initial) and immediate and long-term facial nerve function using House Brackmann (HB) rating scale. Results Intraoperative TCMEP data and immediate and follow-up FN outcome are reported for 52 patients undergoing CPA tumor resection. Patients with unsatisfactory facial outcome (HB >2) at follow-up had an average deltaTCMEP of 57 V, whereas those with HB I or II had a mean deltaTCMEP of 0.04 V (t = -2.6, p < 0.05.) Intraoperative deltaTCMEP did not differ significantly between groups with satisfactory (HB I, II) and unsatisfactory (HB > 2) facial function in the immediate postoperative period. Conclusion Intraoperative TCMEP of the facial nerve can be a valuable adjunct to conventional facial nerve electromyography during resection of tumors at the CPA. Intraoperative deltaTCMEP >57 V may be worrisome for long-term recovery of satisfactory facial nerve function.

Preserving facial nerve function is a primary goal and a key decision factor in the comprehensive management of vestibular schwannoma and other cerebellopontine angle (CPA) tumors. To evaluate the use of the pattern of facial paralysis recovery in the early postoperative months as a sole predictor in selecting patients for facial nerve grafting after CPA tumor resection when cranial nerve VII is uninterrupted. Sixty-two patients with facial paralysis and uninterrupted cranial nerve VII who developed facial paralysis after CPA tumor resection at The Johns Hopkins Hospital were followed up prospectively to assess for spontaneous recovery and to determine candidacy for facial reanimation surgery. The study dates and dates of analysis were January 1, 2009, to March 31, 2015. After a minimum of 6 months of clinical follow-up and no signs of clinical recovery, patients underwent facial nerve exploration and a masseteric or hypoglossal nerve transfer. Intraoperative direct nerve stimulation was performed to assess for the presence of subclinical reinnervation. Patients were followed up for a minimum of 18 months after surgery to evaluate outcomes. Facial function and recovery were studied objectively with a Smile Recovery Scale, Facial Asymmetry Index, and House-Brackmann (HB) grading system. Other outcome measures included the duration of paralysis, time to recovery, and evidence of synkinesis. Sixty-two patients (33 men, 29 women; mean age 51.8 years) with uninterrupted facial nerves after CPA tumor resection developed HB grade IV, V, or VI facial paralysis. Ten patients underwent nerve grafting by 12 months, 9 patients received grafting after 12 months, and 8 patients had no intervention. Thirty-five patients spontaneously recovered. In all patients who underwent nerve grafting, there were no detectable facial muscle movements or electromyographic response to direct facial nerve stimulation suggestive of occult reinnervation. Overall, early facial reanimation surgery resulted in a shorter total duration of paralysis. Masseteric nerve grafting resulted in earlier recovery compared with hypoglossal nerve grafting (5.6 vs 10.8 months, P = .005). Patients who showed no signs of recovery by 6 months after CPA surgery but declined facial reanimation surgery demonstrated at best HB grade V recovery after 18 months of observation. The recovery pattern in the early postoperative period among patients who develop facial paralysis after CPA tumor resection is a useful clinical tool in selecting patients for facial reanimation surgery. Patients can be counseled for facial reanimation surgery as early as 6 months after surgery because satisfactory facial functional recovery is unlikely to occur when there is no clinical evidence of spontaneous nerve regeneration in the first 6 months. 3.

The objective of this study is to preliminarily investigate the surgical safety, efficacy, techniques, and clinical value of fully neuroendoscopic surgery for the resection of cerebellopontine angle (CPA) tumors via a retrosigmoid approach. The clinical data of 47 cerebellopontine angle area (CPA) tumors that were treated by full neuroendoscopic surgery from June 2014 to June 2023 were retrospectively analyzed. The efficacy and advantages of the surgical techniques were evaluated based on indicators such as duration of the surgery, neuroendoscopic techniques, intraoperative integrity of nerves and blood vessels, extent of tumor resection, outcomes or postoperative symptoms, and incidence of complications. The 47 cases of cerebellopontine angle tumors include 34 cases of epidermoid cysts, 7 cases of vestibular schwannomas, and 6 cases of meningiomas. All patients underwent fully neuroendoscopic surgery. Twenty tumors were removed using the one-surgeon two-hands technique, and 27 tumors were removed using the two-surgeons four-hands technique. The anatomical integrity of the affected cranial nerves was preserved in all 47 cases. None of the patients suffered a postoperative hemorrhage, cerebrospinal fluid leak, and aseptic or septic meningitis, or died. The rate of total tumor resection was 72.3% (34/47), and the symptom improvement rate was 89.4% (42/47). All patients were followed up for 2 to 12 months, and none died nor showed any signs of tumor recurrence. By analyzing 47 fully neuroendoscopic resections of CPA tumors using the posterior sigmoid sinus approach in our center, we believe that such method allows complete, safe, and effective resection of CPA tumors and is thereby worthy of clinical promotion.

Objective Lateral sinus thrombosis is a potentially devastating but seldom studied complication of cerebellopontine angle (CPA) tumor surgery. Systemic anticoagulation in the early postoperative period has often been avoided due to the potential risks of intracranial hemorrhage. Design Retrospective review. Setting Tertiary referral center. Main Outcome Measures The goal of this study was to identify the frequency, treatment, and outcomes in patients who develop postoperative venous sinus thrombosis following CPA tumor surgery and receive early systemic anticoagulation. Results Of 43 patients with CPA tumors, we report five patients (11.6%) with transverse and/or sigmoid sinus thrombosis following resection of the tumor, four of which were detected on routine early postoperative noncontrast computed tomography (CT) scan. The thrombosis was confirmed in all cases with CT venography or magnetic resonance venography. Affected patients had significantly larger tumors than controls and tended to undergo longer operations. These patients were treated with immediate anticoagulation (intravenous heparin, followed by Coumadin for 6 months) without complication. Conclusion Venous sinus thrombosis is an underrecognized complication of CPA surgery, but it can be diagnosed in the early postoperative period by noncontrast CT imaging. Early postoperative initiation of systemic anticoagulation appears safe and effective to prevent the progression of thrombosis and its consequences.

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.

Cerebellopontine angle (CPA) tumors present surgical challenges due to their proximity to the facial nerve. Despite preservation efforts, facial nerve paresis is a major issue. This study aims to identify key factors affecting facial nerve preservation during microsurgical resection of large CPA tumors in a low- and middle-income countries (LMIC) setting. This retrospective cross-sectional study, conducted at Aga Khan University, included patients who underwent microsurgical resection of large (>3 cm) CPA tumors with House-Brackmann (HB) grades 1-4. Postoperative facial nerve function was assessed using the HB grading system. Data was extracted from medical records and analyzed using SPSS 22. This study analyzed 95 patients (M:F=1:1.16, mean age 44.24±13.71 years) with CPA tumors who underwent microsurgical resection. Common presenting complaints included a complete hearing loss (57.9%), headache (52.6%), and abnormal gait (40%). Preoperative facial nerve function was normal (HB grade I) in 75%, with 19%, 7%, and 2% having HB grades II, III, and IV, respectively. Schwannoma (69.5%), meningioma (16.8%), and epidermoid cyst (10.5%) were the most common diagnoses. Postoperative preservation of facial nerve function was achieved in 73.7% of patients. At six months, HB grades I and II were observed in 64% and 11.5%, respectively, while none had complete facial nerve palsy. On univariate analysis, larger tumor size and higher HB grade correlated with worse facial nerve outcomes (p=0.02). Complications were more frequent in patients with worsened outcomes (72% vs. 38.6%, p=0.004). However, in multivariate analysis, only preoperative HB grade was identified as a predictor. Facial nerve preservation during CPA tumor resection is influenced by intrinsic tumor characteristics, surgical complexity, and patient-specific factors. Detailed preoperative counseling is crucial to set realistic expectations.

Diluted intracisternal papaverine for microvascular protection of cranial nerves during vestibular schwannoma and cerebello-pontine angle surgery. Commentary and review of the literature

ObjectiveTo summarize the outcomes of 1000 consecutive microsurgical resection of cerebellopontine angle tumors.Study DesignRetrospective cohort study.SettingSingle tertiary care institution.MethodsWe analyzed 1000 patients who underwent microsurgical resection of cerebellopontine angle tumors between November 2017 and August 2024. Patient and tumor‐related characteristics are summarized, and the extent of resection, facial nerve function, hearing preservation, and postoperative complications are described. Volumetric analysis was used to assess resection completeness.ResultsThe median patient age was 49 years (interquartile range [IQR] 40‐58), with 62% female and 74% Caucasian. Surgical approaches included 46.5% translabyrinthine (TL), 24.6% retrosigmoid (RS), 24.1% middle cranial fossa (MCF), and 4.8% other. The median tumor size was 19 mm (IQR 12‐27), and 52% were left‐sided. Overall, volumetric analysis for vestibular schwannoma tumors revealed that 88% of patients had ≤2% tumor volume remaining, 4% had >2% and ≤5%, 4% had >5% and ≤10%, and 4% had >10%. Additionally, the average extent of resection was 98% volume reduction. The most common postoperative complication was cerebrospinal fluid leak (10%), with 77% of cases treated by lumbar drain. Postoperative House‐Brackmann (HB) scores of I or II were achieved in 88% of patients, which had improved to 90% at the time of last follow‐up. Hearing preservation was 62% for MCF and 33% for RS cases.ConclusionMicrosurgical resection of cerebellopontine angle tumors yields favorable outcomes, particularly in preserving facial nerve function and hearing. Tumor size and surgical approach impacted hearing preservation, with the middle fossa approach being most effective for smaller tumors.

The combined microscopic and endoscopic technique has shown significant advantages in the management of various lesions through different approaches. Endoscopic-assisted techniques have frequently been applied to cerebellopontine angle (CPA) surgery in the context of minimally invasive craniotomies. In this paper the authors report on the use of the endoscope in the CPA as a tool to increase the extent of resection, minimize complications, and preserve the function of the delicate CPA structures. They also describe a technique of the simultaneous use of the microscope and endoscope in the CPA and dissection of CPA tumors under tandem endoscopic and microscopic vision to overcome the shortcomings of introducing the endoscope alone in the CPA. The reliability of using the microscope alone in dissecting CPA tumors is evaluated, as is the effectiveness of the combined technique in increasing the resectability of various types of CPA tumors. The authors conducted a retrospective analysis of 50 patients who underwent combined microscopic-endoscopic resection of CPA tumors by the senior author over a period of 3 years (February 2011 to February 2014) at Brigham and Women's Hospital, Harvard Medical School. The reliability of the extent of microscopic removal was evaluated with endoscopic exploration. Additional resection was performed with both microscopic and the combined microscopic-endoscopic technique. Endoscopically verified total resection was validated by intraoperative or postoperative MRI. The function of the cranial nerves was evaluated to assess the impact of the combined technique on their function. A tumor remnant was endoscopically identified in 69% of the 26 patients who were believed to have microscopic total resection. The utilization of the endoscopic visualization and dissection increased endoscopically verified total removal to 38 patients, and 82% of these patients had no sign of residual tumor on postoperative imaging. The technique was most effective with epidermoid tumors. There were a total of 17 new cranial nerve deficits in 10 patients. Preoperative fifth cranial nerve deficits improved in 52% and hearing improved in 29% of patients after surgery. This method provides simultaneous microscopic and endoscopic visualization and dissection techniques through skull-base approaches to CPA tumors. It overcomes some of the shortcomings of endoscopic-assisted surgery, further extends the surgical field, and increases the radicality of tumor resection with good functional outcomes.

Advances and future directions in the care of patients with facial paralysis

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.

Cerebellopontine angle metastasis from pancreatic cancer: a case report.

Objective To evaluate the treatment effects of hypoglossal-facial 'side’-to-side neurorrhaphy using a predegenerated sural nerve autograft for facial paralysis following tumor resection in cerebellopontine angle (CPA) area. Methods We followed up 48 patients who developed facial paralysis as a result of CPA tumor removal and underwent hypoglossal-facial 'side’-to-side neurorrhaphy using a predegenerated sural nerve autograft between June 2013 to February 2016 at Neurosurgery Department of Beijing Tiantian Hospital, Capital Medical University. Eight other patients who served as controls did not receive any repair treatment. Patients in both groups received rehabilitation exercises and their static and dynamic facial images were collected. Electrophysiological tests of the facial nerve were conducted including electromyography, motor nerve conduction and F wave. The patients' facial nerve functions were assessed according to House-Brackmann grading scale(H-B scale). The follow-up lasted 2-36 months with an average of (12.1±13.4) months. Results In the surgical treatment group, 24/48 patients were found postoperatively to have significant facial function improvement on H-B scale, 21/48 patients to have improvement, and 3/48 remained unchanged. In the control group, 1/8 patient was found to have significant facial function improvement on H-B scale, 2/8 had improvement and 5/8 remained unchanged associated with marked atrophy of paralyzed facial muscles. Significant difference was identified in the facial function improvement on H-B scale between the surgical treatment and control groups (P<0.01). The improvement of facial nerve function was most evident if the surgical repair treatment was performed within the 6 months after the onset of facial paralysis. Conclusions Hypoglossal-facial 'side’-to-side neurorrhaphy may effectively treat facial paralysis resulting from CPA tumor resection. Better recovery of facial nerve function could be achieved when the surgical treatment is performed within the 6 months after the onset of the facial paralysis. Key words: Central nervous system neoplasms; Cerebellopontine angle; Facial paralysis; Transplantation, autologous; 'Side’-to-side neurorrhaphy

Surgery for tumors in the cerebellopontine angle is always a significant challenge due to the densely packed neurovascular structures, the narrow deep location, and the complex relationship between the lesions and surrounding neurovascular structures. Recently, great attention has been given to the neuroendoscope for its exclusive advantages, which have added a new dimension to many classical microscopic surgeries. However, the feasibility and advisability of fully endoscopic neurosurgery for cerebellopontine angle tumors remain to be further evaluated. We retrospectively collected the clinical outcomes and endoscopic surgical experience of 12 patients with tumors in the cerebellopontine angle (CPA) from January 2022 to April 2024 in our department. We analyzed patients' records, radiological neuroimaging, tumor-related variables, surgical procedures, and postoperative outcomes in detail. All patients were regularly followed up with neurological examinations and magnetic resonance imaging (MRI)/computed tomography (CT). The pathology of the series included five cases of acoustic neuroma, six cases of meningioma, and one case of teratoma. The mean largest diameter of the lesion was 29.5mm ±8.5 mm. Headache, hearing loss, and dizziness were the top three most common symptoms. All tumors were resected using the hand technique. No hemorrhage, cerebrospinal fluid leaks, or intracranial infections occurred. All patients with meningioma achieved Simpson grade II resection, and the remaining tumors underwent gross total resection, confirmed by both intraoperative and postoperative imaging. Overall, 91.7% of patients maintained normal facial nerve function postoperatively (HB1). One patient with acoustic neuroma experienced transient facial paralysis after surgery (HB2), which resolved during follow-up at 3 months postoperation. Clinical symptoms of all the other patients were resolved or ameliorated after surgery, with no new neurological deficits. The Karnofsky Performance Scale (KPS) scores remained unchanged or improved for all patients postoperatively. With the accumulation of experience and technological progress, the fully endoscopic retrosigmoid approach could enable safe and effective resection of cerebellopontine angle tumors, providing a panoramic view and illumination of deep-seated structures.