The fate of the tumor remnant after less-than-complete acoustic neuroma resection

Long-term hearing prognosis after vestibular schwannoma surgery with retrolabyrinthine approach

PURPOSE

The retrolabyrinthine approach is a surgical method designed to preserve hearing after surgery. When paired with intraoperative monitoring and an endoscope, this approach has demonstrated high rates of postoperative hearing preservation. However, the long-term prognosis of hearing preservation after utilizing this approach for vestibular schwannomas remains unexplored. This study aimed to examine the long-term outcomes of preserved hearing, providing insights into the suitability of the retrolabyrinthine approach for hearing preservation surgery.

METHODS

This study included 34 patients with preserved hearing after vestibular schwannoma surgery using the retrolabyrinthine approach at a single center. Long-term hearing prognosis and requirement for additional interventions were retrospectively examined.

RESULTS

Immediate after post-operative hearing preservation rate was 71.7%. Among the 34 patients with preserved hearing post-vestibular schwannoma surgery, four (11.8%) required additional interventions. Other patients experienced a gradual deterioration in their hearing status, with an approximate 10 dB decline during the 5-year follow-up; however, a serviceable hearing level persisted long after the surgery in these individuals.

CONCLUSIONS

This study indicated the rationale for the retrolabyrinthine approach as a hearing preservation surgery for vestibular schwannomas, emphasizing its long-term hearing prognosis.

The Impact of Tumor Elongation on Facial Nerve Outcome after Surgery for Koos Grade 3 and 4 Vestibular Schwannomas in the Semi-Sitting Position via the Retrosigmoid Approach

Background: Facial nerve paralysis is a severe dysfunction after vestibular schwannoma (VS) surgery. Methods: This monocentric study analyzed 61 patients who underwent sporadic VS surgery in a standardized manner. The primary endpoint was the facial nerve outcome (FNO) at 3 months after VS surgery. FNO was dichotomized into "good" (House-Brackmann (HB) score ≤ 2) and "poor" (HB > 2). Results: Poor FNO was observed in 11 patients (18.0%) at 3 months after VS surgery. Radiomic tumor shape features were analyzed, and the AUC of elongation in the prediction of a poor HB at 3 months was 0.70 (95% CI: 0.56-0.85, p = 0.03) and the optimum threshold value (≤/>0.35) yielded a sensitivity and specificity of 64.0% and 75.4%, respectively. Multivariable logistic regression analyses considering the extent of resection (0.35) revealed that more elongated VSs (≤0.35; OR: 5.8; 95%CI: 1.2-28.2; p = 0.03) and those with an increased EoR (≥93.4%; OR: 6.5; 95%CI: 1.0-42.5; p = 0.05) are independently associated with poorer FNO at 3 months after surgery. Conclusions: Highly elongated VS shape seems to be a risk factor for worsened facial nerve outcome at 3 months after surgery for Koos grade 3 and 4 tumors.

Likelihood-of-harm/help of microsurgery compared to radiosurgery in large vestibular schwannoma

PURPOSE

It has been shown that in large vestibular schwannomas (VS), radiosurgery (SRS) is inferior with respect to tumor control compared to microsurgical resection (SURGERY). However, SURGERY poses a significantly higher risk of facial-function deterioration (FFD). The aim of this study was to illustrate the effectiveness in terms of number-needed-to-treat/operate (NNO), number-needed-to-harm (NNH), and likelihood-of-harm/help (LHH) by comparing both treatment modalities in large VS.

METHODS

This was a retrospective, dual-center cohort study. Tumor size was classified by Hannover Classification. Absolute risk reduction and risk increase were used to derive additional estimates of treatment effectiveness, namely NNO and NNH. LHH was then calculated by a quotient of NNH/NNO to illustrate the risk-benefit-ratio of SURGERY.

RESULTS

Four hundred and forty-nine patients treated met the inclusion criteria. The incidence of tumor recurrence was significantly higher in SRS (14%), compared to SURGERY (3%) resulting in ARR of 11% and NNO of 10. At the same time, SURGERY was related to a significant risk of FFD resulting in an NNH of 12. Overall, the LHH calculated at 1.20 was favored SURGERY, especially in patients under the age of 40 years (LHH = 2.40), cystic VS (LHH = 4.33), and Hannover T3a (LHH = 1.83) and T3b (LHH = 1.80).

CONCLUSIONS

Due to a poorer response of large VS to SRS, SURGERY is superior with respect to tumor control. One tumor recurrence can be prevented, when 10 patients are treated by SURGERY instead of SRS. Thus, LHH portrays the benefit of SURGERY in large VS even when taking raised FFD into account.

Outcomes of Near-Total and Subtotal Resection of Sporadic Vestibular Schwannoma: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate tumor control and facial nerve outcomes after gross-total (GTR), near-total (NTR), and subtotal resection (STR) of sporadic vestibular schwannomas (VS).

DATA SOURCES

PubMed, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus databases were searched in August 2021 through inception following PRISMA guidelines.

REVIEW METHODS

English language articles reporting tumor control and facial nerve outcomes of adults (≥18 years) with NTR and STR of VS were evaluated. Study characteristics, demographics data, tumor characteristics, type of surgical intervention, and outcome measures on tumor control and facial nerve function were collected. Pooled relative risk (RR) estimates for tumor recurrence and facial nerve outcomes were calculated and stratified by extent of resection.

RESULTS

From an initial search of 2504 articles, 48 studies were included in the analysis. When comparing 1108 patients who underwent NTR to 3349 patients with GTR, the pooled RR of recurrence in the NTR cohort was 2.94 (95% confidence interval [CI] 1.65-5.24, P = .0002). When comparing 1016 patients who underwent STR to 6171 patients with GTR, the pooled RR of recurrence in the STR cohort was 11.50 (95% CI 6.64-19.92, P < .0001). Estimates for risk of tumor regrowth for less-than-complete resection are presented. There was no elevated risk of adverse facial nerve outcome (defined as House-Brackmann grade III and above) in each category of extent of resection compared to GTR.

CONCLUSION

Extent of resection predicts risk of tumor recurrence/regrowth following microsurgical resection. Favorable facial nerve outcome should be weighed against the increased risk of regrowth and the potential need for further treatment.

Impact of Latency Variations on the Predictive Value of Facial Nerve Proximal-to-Distal Amplitude Ratio during Vestibular Schwannoma Surgery

Introduction  This study highlights the relation between compound muscle action potential (CMAP) latency variations and the predictive value of facial nerve (FN) proximal-to-distal (P/D) amplitude ratio measured at the end of vestibular schwannoma resection. Methods  Forty-eight patients underwent FN stimulation at the brainstem (proximal) and internal acoustic meatus (distal) using a current intensity of 2 mA. The proximal latency and the P/D amplitude ratio were assessed. House-Brackmann grades I & II indicated good FN function, and grades III to VI were considered fair/poor function. A P/D amplitude ratio > 0.6 was used as a cutoff to indicate a good FN function, while a ratio of ≤ 0.6 indicated a fair/poor FN function. Results  The P/D amplitude ratio was measured for all patients, and the calculated sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) were 85.2, 85.7, 88.5, and 81.8%, respectively. The CMAPs from the mentalis muscle were then classified based on their proximal latency into group I (< 6 ms), group II (6-8 ms), and group III (> 8 ms). The SE, SP, PPV, and NPV became 90.5, 90.9, 95, and 83.3%, respectively, in group II. In group I, SE and NPV increased, whereas SP and PPV decreased. While in group III, SP and PPV increased, whereas SE and NPV decreased. Conclusion  At a latency between 6 and 8 ms, the P/D amplitude ratio was predictive of outcomes with high SE and SP. When latency was < 6 ms or > 8 ms, the same predictive ability was not observed. Knowing the strengths and limitations is important for understanding the predictive value of the P/D amplitude ratio.

Subtotal resection of vestibular schwannoma with subsequent Gamma Knife irradiation - tumor growth control, facial and cochlear nerve outcome - preliminary results

<b>Introduction:</b> The choice of treatment of vestibular schwannoma (VS) depends on several factors, including the tumor size, the patient's age and overall health, and the presence and severity of symptoms.<b>Aim:</b> The aim of the study was to assess the effectiveness of intentional subtotal resection (STR) of tumor followed by Gamma Knife surgery (GKS) in patients with larger VS (Koos 3 and 4).<b>Materials and methods:</b> The retrospective analysis was performed on 18 patients. Data of VS volumes measured in MRI, the facial nerve function assessed in the House-Brackmann scoring system (HB), and the results of audiological examination expressed on the Gardner-Robertson scale (GR) were collected preoperatively, postoperatively, and post-GKS.<b>Results:</b> Preoperatively, the main symptom was hearing loss observed in 13 out of 18 patients. The facial nerve function was assessed as HB 1 in 16, whereas HB 2 in 2 patients. The mean volume of the tumor in the initial MRI amounted to 16.81 cm³ . Postoperatively, the facial nerve was assessed as HB 1 or 2 in 16, whereas HB 3 in 2 patients. Serviceable hearing was presented by only 4 persons. The Mean diameter of the tumor after subtotal surgery amounted to 3.16 cm³ , 1.83 cm³ after GKS, and 1.58 cm³ at the last follow-up. The facial nerve function and hearing level remained the same as before GKS in all patients.<b>Conclusions:</b> STR followed by GKS can be a safe and effective method of treatment of large VS concerning the functional outcome of the facial nerve and the tumor volume growth control.

Facial Nerve Preserving Subtotal Excision for Large Vestibular Schwannoma: An Institution-Based Functional Outcome Study

BACKGROUND

The ideal goal of treatment for medium to large vestibular schwannoma is complete tumor removal with preservation of all cranial nerves. However, despite the advancements in microsurgery and intraoperative monitoring, the risk of facial nerve dysfunction following total resection varies between 31% and 57%. Currently, the goal of treatment for large tumors is shifting from total excision to facial nerve preservation.

OBJECTIVE

To evaluate the facial nerve outcome in patients who underwent subtotal excision with or without subsequent gamma knife radiosurgery for large vestibular schwannomas in our institute.

METHODS AND MATERIAL

All patients who underwent primary surgery for large vestibular schwannomas between January 2012 and December 2016 were analyzed retrospectively. Cases where total excision was not done and a residue was left behind to prevent facial nerve injury during surgery were included in the study.

RESULTS

A total of 52 patients who met the inclusion criteria were analyzed. At final follow-up, 70% of patients had good facial nerve function (H-B grade 1 and 2). In patients with normal facial nerve function preoperatively, 81% (25/31) of them had good facial nerve outcomes (H-B grade 1 and 2), whereas in patients with preexisting facial nerve deficits, nearly 62% (13/21) of them either maintained or had improvement in their facial nerve grades.

CONCLUSION

Good facial nerve outcomes and tumor control rate is obtained by subtotal excision of VS followed by upfront or delayed GKRS; however, there is a need for long-term follow-up to detect recurrences in these slow-growing tumors.

Comparative Analysis on Vestibular Schwannoma Surgery with and without Intraoperative Fluorescein Sodium Enhancement

BACKGROUND

Vestibular schwannoma (VS), also known as acoustic neuroma, is a benign, well-encapsulated, and slow-growing tumor that originates from Schwann cells, which form the myelin sheath around the vestibulocochlear nerve (VIII cranial nerve). The surgical treatment of this condition presents a challenging task for surgeons, as the tumor's location and size make it difficult to remove without causing damage to the surrounding structures. In recent years, fluorescein sodium (FS) has been proposed as a tool to enhance surgical outcomes in VS surgery. This essay will provide an analytical comparison of the use of FS in VS surgery, evaluating its benefits and limitations and comparing surgical outcomes with and without FS-assisted surgery.

METHODS

In a retrospective study conducted at San Filippo Neri Hospital, we examined VS cases that were operated on between January 2017 and December 2023. The patients were divided into two groups: group A, which consisted of patients who underwent surgery without the use of FS until January 2020 (102 cases), and group B, which included patients who underwent surgery with FS after January 2020 (55 cases). All operations were performed using the retrosigmoid approach, and tumor size was classified according to the Koos, et al. classification system. The extent of surgical removal was evaluated using both the intraoperative surgeon's opinion and postoperative MRI imaging. Preoperatively and postoperatively, facial nerve function and hearing were assessed. In group B, FS was used to assist the surgical procedures, which were performed using a surgical microscope equipped with an integrated fluorescein filter. Postoperative clinical and MRI controls were performed at six months and annually, with no patients lost to follow-up.

RESULTS

This study investigated the impact of intraoperative fluorescein exposure on tumor resection and clinical outcomes in patients with VS. The study found a statistically significant difference in the tumor resection rates between patients who received fluorescein intraoperatively (p = 0.037). Further analyses using the Koos classification system revealed a significant effect of fluorescein exposure, particularly in the Koos 3 subgroup (p = 0.001). Notably, no significant differences were observed in hearing loss or facial nerve function between the two groups. A Spearman correlation analysis revealed a positive correlation between tumor size and Koos, age, and size, but no significant correlation was found between facial nerve function tests.

CONCLUSIONS

FS-assisted surgery for VS may potentially enhance tumor resection, allowing for more comprehensive tumor removal.

An Artificial Neural Network Model for Predicting Postoperative Facial Nerve Outcomes After Vestibular Schwannoma Surgery

BACKGROUND AND OBJECTIVES

The emergence of machine learning models has significantly improved the accuracy of surgical outcome predictions. This study aims to develop and validate an artificial neural network (ANN) model for predicting facial nerve (FN) outcomes after vestibular schwannoma (VS) surgery using the proximal-to-distal amplitude ratio (P/D) along with clinical variables.

METHODS

This retrospective study included 71 patients who underwent VS resection between 2018 and 2022. At the end of surgery, the FN was stimulated at the brainstem (proximal) and internal acoustic meatus (distal) and the P/D was calculated. Postoperative FN function was assessed using the House-Brackmann grading system at discharge (short-term) and after 9-12 months (long-term). House-Brackmann grades I-II were considered good outcome, whereas grades III-VI were considered fair/poor. An ANN model was constructed, and the performance of the model was evaluated using the area under the ROC curve for internal validation and accuracy, sensitivity, specificity, and positive and negative predictive values for external validation.

RESULTS

The short-term FN outcome was grades I-II in 57.7% and grades III-VI in 42.3% of patients. Initially, a model using P/D had an area under the curve of 0.906 (internal validation) and an accuracy of 89.1% (95% CI: 68.3%-98.8%) (external validation) for predicting good vs fair/poor short-term FN outcomes. The model was then refined to include only muscles with a P/D with a proximal latency between 6 and 8 ms. This improved the accuracy to 100% (95% CI: 79%-100%). Integrating clinical variables (patient's age, tumor size, and preoperative HB grade) in addition to P/D into the model did not significantly improve the predative value. A model was then created to predict the long-term FN outcome using P/D with latencies between 6 and 8 ms and had an accuracy of 90.9% (95% CI: 58.7%-99.8%).

CONCLUSION

ANN models incorporating P/D can be a valuable tool for predicting FN outcomes after VS surgery. Refining the model to include P/D with latencies between 6 and 8 ms further improves the model's prediction. A user-friendly interface is provided to facilitate the implementation of this model.

[Vestibular Schwannoma: Factors in Therapy Decision-Making]

The treatment of vestibular schwannomas (VS) has always posed a challenge for physicians. Three essential treatment principles are available: wait-and-scan, surgery, and stereotactic radiotherapy. In addition to the type of treatment, decisions must be made regarding the optimal timing of therapy, the combination of different treatment modalities, the potential surgical approach, and the type and intensity of radiation. Factors influencing the therapy decision include tumor location and size or stage, patient age, comorbidities, symptoms, postoperative hearing rehabilitation options, patient preferences, and, not least, the experience of the surgeons and the personnel and technical capabilities of the clinical site. This article begins with a brief overview of vestibular schwannomas, then outlines the fundamental interdisciplinary treatment options, and finally discusses the ENT (ear, nose, and throat)-relevant factors in the therapy decision.

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

Comparison of Surgeons' Assessment of the Extent of Vestibular Schwannoma Resection with Immediate Post Operative and Follow-Up Volumetric MRI Analysis

(1) Background: Incomplete excision of vestibular schwannomas (VSs) is sometimes preferable for facial nerve preservation. On the other hand, subtotal resection may be associated with higher tumor recurrence. We evaluated the correlation between intra-operative assessment of residual tumor and early and follow-up imaging. (2) Methods: The charts of all patients undergoing primary surgery for sporadic vestibular schwannoma during the study period were retrospectively reviewed. Data regarding surgeons' assessments of the extent of resection, and the residual size of the tumor on post-operative day (POD) one and follow-up MRI were extracted. (3) Results: Of 109 vestibular schwannomas meeting inclusion criteria, gross-total resection (GTR) was achieved in eighty-four, near-total (NTR) and sub-total resection (STR) in twenty-two and three patients, respectively. On follow up imaging, volumetric analysis revealed that of twenty-two NTRs, eight were radiographic GTR and nine were radiographic STR (mean volume ratio 11.9%), while five remained NTR (mean volume ratio 1.8%). Of the three STRs, two were radiographic GTR while one remained STR. Therefore, of eighteen patients with available later follow up MRIs, radiographic classification of the degree of resection changed in six. (4) Conclusions: An early MRI (POD#1) establishes a baseline for the residual tumor that may be more accurate than the surgeon's intraoperative assessment and may provide a beneficial point of comparison for long-term surveillance.

Iatrogenic inner ear dehiscence associated with lateral skull base surgery: a systematic analysis of drilling injuries and their causal factors

PURPOSE

Drilling injuries of the inner ear are an underreported complication of lateral skull base (LSB) surgery. Inner ear breaches can cause hearing loss, vestibular dysfunction, and third window phenomenon. This study aims to elucidate primary factors causing iatrogenic inner ear dehiscences (IED) in 9 patients who presented to a tertiary care center with postoperative symptoms of IED following LSB surgery for vestibular schwannoma, endolymphatic sac tumor, Meniere's disease, paraganglioma jugulare, and vagal schwannoma.

METHODS

Utilizing 3D Slicer image processing software, geometric and volumetric analysis was applied to both preoperative and postoperative imaging to identify causal factors iatrogenic inner ear breaches. Segmentation analyses, craniotomy analyses, and drilling trajectory analyses were performed. Cases of retrosigmoid approaches for vestibular schwannoma resection were compared to matched controls.

RESULTS

Excessive lateral drilling and breach of a single inner ear structure occurred in 3 cases undergoing transjugular (n=2) and transmastoid (n=1) approaches. Inadequate drilling trajectory breaching ≥1 inner ear structure occurred in 6 cases undergoing retrosigmoid (n=4), transmastoid (n=1), and middle cranial fossa approaches (n=1). In retrosigmoid approaches the 2-cm visualization window and craniotomy limits did not provide drilling angles to the entire tumor without causing IED in comparison to matched controls.

CONCLUSIONS

Inappropriate drill depth, errant lateral drilling, inadequate drill trajectory, or a combination of these led to iatrogenic IED. Image-based segmentation, individualized 3D anatomical model generation, and geometric and volumetric analyses can optimize operative plans and possibly reduce inner ear breaches from lateral skull base surgery.

Surgical Outcomes Following Vestibular Schwannoma Resection in Patients over the Age of Sixty-five

Objective  Vestibular schwannoma (VS) are benign, often slow growing neoplasms. Some institutions opt for radiosurgery in symptomatic patients of advanced age versus surgical resection. The aim of the study is to analyze surgical outcomes of VS in patients over the age of 65 who were either not candidates for or refused radiosurgery. Methods  This includes retrospective analysis of VS patients between 1988 and 2020. Demographics, tumor characteristics, surgical records, and clinical outcomes were recorded. Patient preference for surgery over radiosurgery was recorded in the event that patients were offered both. Facial nerve outcomes were quantified using House-Brackmann (HB) scores. Tumor growth was defined by increase in size of >2 mm. Results  In total, 64 patients were included of average age 72.4 years (65-84 years). Average maximum tumor diameter was 29 mm (13-55 mm). Forty-five patients were offered surgery or GKRS, and chose surgery commonly due to radiation aversion (48.4%). Gross total resection was achieved in 39.1% ( n  = 25), near total 32.8% ( n  = 21), and subtotal 28.1% ( n  = 18). Average hospitalization was 5 days [2-17] with 75% ( n  = 48) discharged home. Postoperative HB scores were good (HB1-2) in 43.8%, moderate (HB3-4) in 32.8%, and poor (HB5-6) in 23.4%. HB scores improved to good in 51.6%, moderate in 31.3%, and remained poor in 17.1%, marking a rate of facial nerve improvement of 10.9%. Tumor control was achieved in 95.3% of cases at an average follow-up time of 37.8 months. Conclusion  VS resection can be safely performed in patients over the age of 65. Advanced age should not preclude a symptomatic VS patient from being considered for surgical resection.

Salvage Management of Vestibular Schwannoma

The current management of vestibular schwannomas (VS) includes observation, microsurgery (MS), and stereotactic radiosurgery (SRS) or radiotherapy, and treatment failures may occur with any primary modality. SRS is most often used for microsurgical failures, as it carries a low risk of adverse events. Salvage MS following previous MS is reserved for specific cases and can present certain surgical challenges. Irradiation failures can be managed with both salvage MS and repeat SRS. This article is intended to review an approach to the failure of primary interventions for VS, with a focus on the time interval between modalities, rates of tumor control, functional outcomes, and possible complications.

Hypofractionated stereotactic radiotherapy for large vestibular schwannomas and the impact of pre-radiation debulking surgery on dosimetry and clinical outcomes

Introduction:

This study was aimed to evaluate the outcomes of patients with large (>2 cm in great diameter) vestibular schwannomas (VSs) treated with hypofractionated stereotactic radiotherapy (HFSRT) compared to small (<2 cm) ones and the impact of debulking surgery prior to radiation for large VSs.

Methods:

Fifty-nine patients with VSs treated with HFSRT (25 Gy in 5 fractions) were evaluated by tumour size and surgical status. Patients were divided based on tumour size: small VSs (n = 42) and large VSs (n = 17). The large group was further divided into the groups of pre-treatment debulking surgery (n = 8) and no surgery (n = 9). Rates of tumour control, brainstem necrosis and neurologic dysfunction were assessed following treatment. Pre-surgical magnetic resonance imaging (MRI) were used to generate hypothetical HFSRT plans to compare the effect of debulking surgery on dosimetry. Normal tissue complication probability (NTCP) modelling was performed to compare toxicity probabilities with and without surgical debulking in large VSs.

Results:

There was no statistical difference of tumour control rate between small and large VSs with 100% for small tumours and 94·1% for large tumours (p = 0·12), respectively. In large VSs patient, the tumour control rate of HFSRT was 100% (8/8) for surgically debulked patients and 89% (8/9) for non-surgically debulked patients (p = 0·35). There were no patients who experienced brainstem necrosis or progression of facial and trigeminal nerve symptoms after HFSRT in the entire groups of patients. Surgical debulking large VSs did not change the maximum point dose of brainstem (p = 0·98), but significantly decreased volumes of VSs and changed the minimum dose to the hottest 0·5 cc of tumour (p = 0·016) as well as the volume receiving at least 23 Gy (p = 0·023). NTCP modelling revealed very low rates (average < 1%) of brainstem toxicity with or without surgical debulking, but there was a significant difference favoring surgery (p < 0·05).

Conclusions:

HFSRT is a safe and effective treatment for both small and large VSs and is a viable option for patients with large VSs who cannot undergo surgery, if NTCP of pre-debulking HFSRT dosimetry is lower.

A comparative study of microsurgery and gamma knife radiosurgery in vestibular schwannoma evaluating tumor control and functional outcome

Background

Both stereotactic radiosurgery (SRS) and microsurgical resection (SURGERY) are available as treatment options for sporadic vestibular schwannoma (VS). There are very few direct comparative studies comparing both treatment modalities in large cohorts allowing detailed subgroup analysis. This present study aimed to compare the nuances in the treatment of VS by SURGERY and SRS in 2 highly specialized neurosurgical centers.

Methods

This is a retrospective bicentric cohort study. Data from patients treated between 2005 and 2011 were collected retrospectively. Recurrence-free survival (RFS) was assessed radiographically by contrast-enhanced magnetic resonance imaging.

Results

The study population included N = 901 patients with a mean follow-up of 7 years. Overall, the incidence of recurrence was 7% after SURGERY, and 11% after SRS with superior tumor control in SURGERY in the Kaplan-Meier-analysis (P = 0.031). In small tumors (Koos I and II), tumor control was equivalent in both treatment arms. In large VS (Koos III and IV), however, RFS was superior in SURGERY. The extent of resection correlated with RFS (P < .001). Facial and hearing deterioration was similar in both treatment arms in small VS, but more pronounced in SURGERY of large VS. Tinnitus, vertigo, imbalance, and trigeminal symptoms were more often improved by SURGERY than SRS.

Conclusions

SRS can achieve similar tumor control compared to SURGERY in smaller VS (Koos I and II)-with similar postinterventional morbidities. In large VS (Koos III and IV), long-term tumor control of SRS is inferior to SURGERY. Based on these results, we suggest that if combination therapy is chosen, the residual tumor should not exceed the size of Koos II.

Postoperative Impact of Pontocerebellar Angle Surgery on the Quality of Life in Patients with Vestibular Schwannoma

BACKGROUND

Vestibular Schwannomas are benign tumors arising from the VIII CN. Surgical treatment is indicated in case of tumors larger than 2.5 cm in the cerebellopontine angle or in the case of cranial nerve dysfunction. The aim of the present study was to evaluate the QoL by means of the PANQOL questionnaire in a group of surgically treated patients mainly affected by large and giant VS Methods: All patients underwent preoperative and postoperative otoneurological evaluation and gadolinium enhanced MRI and they completed, independently, the PANQOL questionnaire at last follow up.

RESULTS

70% of patients presented with large Koos III or IV VS Each domain of PANQOL showed a strong correlation with the total PANQOL score. In relation to the postoperative facial nerve function, patients with poorer function showed significantly lower score in the facial dysfunction and pain, patients with postoperative balance problems showed a significantly lower PANQOL score for domains of balance and pain.

CONCLUSIONS

This study showed that postoperative QoL of patients was acceptable even if there were some domains that were more affected, such as hearing and balance domains; therefore, the lowest scores suggest the need for vestibular rehabilitation programs and strategies that improve postoperative hearing.

Distinct immune signature predicts progression of vestibular schwannoma and unveils a possible viral etiology

BACKGROUND

The management of sub-totally resected sporadic vestibular schwannoma (VS) may include observation, re-resection or irradiation. Identifying the optimal choice can be difficult due to the disease's variable progression rate. We aimed to define an immune signature and associated transcriptomic fingerprint characteristic of rapidly-progressing VS to elucidate the underpinnings of rapidly progressing VS and identify a prognostic model for determining rate of progression.

METHODS

We used multiplex immunofluorescence to characterize the immune microenvironment in 17 patients with sporadic VS treated with subtotal surgical resection alone. Transcriptomic analysis revealed differentially-expressed genes and dysregulated pathways when comparing rapidly-progressing VS to slowly or non-progressing VS.

RESULTS

Rapidly progressing VS was distinctly enriched in CD4⁺, CD8⁺, CD20⁺, and CD68⁺ immune cells. RNA data indicated the upregulation of anti-viral innate immune response and T-cell senescence. K - Top Scoring Pair analysis identified 6 pairs of immunosenescence-related genes (CD38-KDR, CD22-STAT5A, APCS-CXCR6, MADCAM1-MPL, IL6-NFATC3, and CXCL2-TLR6) that had high sensitivity (100%) and specificity (78%) for identifying rapid VS progression.

CONCLUSION

Rapid progression of residual vestibular schwannoma following subtotal surgical resection has an underlying immune etiology that may be virally originating; and despite an abundant adaptive immune response, T-cell immunosenescence may be associated with rapid progression of VS. These findings provide a rationale for clinical trials evaluating immunotherapy in patients with rapidly progressing VS.

Factors Influencing Personalized Management of Vestibular Schwannoma: A Systematic Review

Management of vestibular schwannoma (VS) is a complex process aimed at identifying a clinical indication for fractionated stereotactic radiotherapy (sRT) or microsurgical resection or wait and scan (WS). The aim of the review was to clarify which patient and tumor parameters may lead to different therapeutic choices, with a view to a personalized VS approach. A systematic review according to Preferred Reporting Items for Systematic Review and Meta-Analysis criteria was conducted between February and March 2022. The authors defined six parameters that seemed to influence decision-making in VS management: 1-incidental VS; 2-tumor size; 3-tumor regrowth after sRT; 4-subtotal resection; 5-patients' age; 6-symptoms. The initial search yielded 3532 articles, and finally, 812 articles were included. Through a qualitative synthesis of the included studies, management strategies were evaluated and discussed. An individualized proposal of procedures is preferable as compared to a single gold-standard approach in VS decision-making. The most significant factors that need to be considered when dealing with a VS diagnosis are age, tumor size and hearing preservation issues.

Evaluating growth trends of residual sporadic vestibular schwannomas: a systematic review and meta-analysis

BACKGROUND

Gross total resection remains the gold-standard approach for vestibular schwannomas (VS) when surgery is indicated. In select cases, incomplete resection (IR) becomes a desired alternative to preserve the facial nerve function and the patient's quality of life. While a lot of earlier studies described incompletely resected sporadic VSs as dormant, more recent studies reported a higher growth rate following IR, therefore an evaluation of the residual VS growth rates could have important implications for the follow-up treatment protocols and provide relevant information for neurosurgeons, neuro-otologists, neuropathologists, and radiologists. Although prognostic factors predicting preoperative VS growth have been previously investigated, these factors have not been investigated following IR. Our review aims to examine the growth rate of residual sporadic VS following IR and to examine variables associated with the regrowth of residual VS.

METHODS

The review was conducted in accordance with the PRISMA guidelines. Six databases (MEDLINE (Ovid), Embase (Ovid), CINAHL Plus (EBSCO), Cochrane Central Register of Controlled Trials (CENTRAL), WHO International Clinical Trials Registry Platform and UK Clinical Trials Gateway (WHO ICTRP) were searched. Full-text articles analysing growth rates in at least ten patients who had residual VS after IR were assessed. We conducted a meta-analysis using a random-effects model via RevMan.

RESULTS

14 studies totalling 849 patients were included in the analysis. The mean planimetric growth rate was 1.57 mm/year (range 0.16-3.81 mm/year). The mean volumetric growth rate was 281.725 mm³/year (range 17.9-530.0 mm³/year). Age, sex, pre-operative tumour size/volume, cystic tumour sub-type, MIB-1 index, and intracanalicular tumour location were not associated with residual growth. Residual tumour size/volume was statistically significant to growth (OR = 0.65, 95% CI 0.47-0.90, p = 0.01). Radiological re-growth occurred in an average of 26.6% of cases (range 0-54.5%).

CONCLUSION

From our analysis, only the residual tumour volume/size was associated with residual VS growth. Therefore, close postoperative surveillance for the first year, followed by an annual MRI scan for at least 5 years, and subsequently extended interval surveillance remains of utmost importance to monitor disease progression and provide timely surgical and adjuvant interventions. Our study shows that future work should be aimed at molecular and histological characteristics of residual VSs to aid prognostic understanding of growth.

Predictors of Recurrence After Sub-total or Near-total Resection of Vestibular Schwannoma: Importance of Tumor Volume and Ventral Extension

OBJECTIVE

To evaluate the predictors of remnant tumor regrowth and need for salvage therapy after less than gross total resection (GTR) of vestibular schwannoma (VS).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary neurotologic referral center.

PATIENTS

Patients who underwent VS resection between 2008 and 2019 either with GTR, near total resection (NTR), and subtotal resection (STR).

INTERVENTIONS

Microsurgical resection, salvage radiosurgery.

MAIN OUTCOME MEASURES

Regrowth free interval, salvage free interval, tumor doubling rate.

RESULTS

Three hundred eighty five cases (GTR = 236, NTR = 77, and STR = 71) from 2008 to 2019 were included. STR cohort had much larger and complex tumors with significant differences in tumor volume, ventral extension and brainstem compression (p  < 0.001). On single predictor analysis, tumor volume, ventral extension, brainstem compression as well as STR strategy was associated with significant increased risk of regrowth and need for salvage therapy. Multivariate analysis revealed STR strategy as significant predictor of regrowth (hazard ratio 3.79, p  < 0.0005). Absolute remnant volume and extent of resection (EOR) did not predict regrowth. A small proportion of cases (NTR = 4%, STR = 15%) eventually needed salvage radiosurgery with excellent ultimate local tumor control with no known recurrence to date.

CONCLUSIONS

Conservative surgical strategy employing NTR or STR can be employed safely in large and complex VS. While there is increased risk of regrowth in the STR cohort, excellent local control can be achieved with appropriate use of salvage radiosurgery. No disceret radiologic or operative predictors of regrowth were identified.

Defining clinically significant tumor size in vestibular schwannoma to inform timing of microsurgery during wait-and-scan management: moving beyond minimum detectable growth

OBJECTIVE

Detection of vestibular schwannoma (VS) growth during observation leads to definitive treatment at most centers globally. Although ≥ 2 mm represents an established benchmark of tumor growth on serial MRI studies, 2 mm of linear tumor growth is unlikely to significantly alter microsurgical outcomes. The objective of the current work was to ascertain where the magnitude of change in clinical outcome is the greatest based on size.

METHODS

A single-institution retrospective review of a consecutive series of patients with sporadic VS who underwent microsurgical resection between January 2000 and May 2020 was performed. Preoperative tumor size cutpoints were defined in 1-mm increments and used to identify optimal size thresholds for three primary outcomes: 1) the ability to achieve gross-total resection (GTR); 2) maintenance of normal House-Brackmann (HB) grade I facial nerve function; and 3) preservation of serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery class A/B). Optimal size thresholds were obtained by maximizing c-indices from logistic regression models.

RESULTS

Of 603 patients meeting inclusion criteria, 502 (83%) had tumors with cerebellopontine angle (CPA) extension. CPA tumor size was significantly associated with achieving GTR, postoperative HB grade I facial nerve function, and maintenance of serviceable hearing (all p < 0.001). The optimal tumor size threshold to distinguish between GTR and less than GTR was 17 mm of CPA extension (c-index 0.73). In the immediate postoperative period, the size threshold between HB grade I and HB grade > I was 17 mm of CPA extension (c-index 0.65). At the most recent evaluation, the size threshold between HB grade I and HB grade > I was 23 mm (c-index 0.68) and between class A/B and C/D hearing was 18 mm (c-index 0.68). Tumors within 3 mm of the 17-mm CPA threshold displayed similarly strong c-indices. Among purely intracanalicular tumors, linear size was not found to portend worse outcomes for all measures.

CONCLUSIONS

The probability of incurring less optimal microsurgical outcomes begins to significantly increase at 14-20 mm of CPA extension. Although many factors ultimately influence decision-making, when considering timing of microsurgical resection, using a size threshold range as depicted in this study offers an evidence-based approach that moves beyond reflexively recommending treatment for all tumors after detecting ≥ 2 mm of tumor growth on serial MRI studies.

Quantitative Evaluation of Proliferative Potential Using Flow Cytometry Reveals Intratumoral Heterogeneity and Its Relevance to Tumor Characteristics in Vestibular Schwannomas

This study sought to explore the existence and clinical significance of intratumoral heterogeneity of proliferative potential in vestibular schwannoma (VS). Rapid intraoperative flow cytometry was utilized with raw samples to measure the proliferative ability of VS. The proliferation index (PI) was defined as the ratio of the number of cells with greater than normal DNA content to the total number of cells. A total of 66 specimens (26 from the intrameatal portion and 40 from the cisternal portion) were obtained from 34 patients with VS. There was a moderate correlation between the PI and MIB-1 labelling index values (R = 0.57, p < 0.0001). In contrast, the patterns of heterogeneity, represented by the proportion of intrameatal PI to cisternal PI, were associated with tumor size (p = 0.03). In addition, preoperative hearing tended to be poor in cases where the intrameatal PI was higher than the cisternal PI (p = 0.06). Our data demonstrated the presence of intratumoral heterogeneity of proliferative potential in VS and its relationship with tumor characteristics. The results of this study may advocate the resection of the intrameatal portion of large VSs treated with planned subtotal resection, especially in cases of poor preoperative hearing function.

A prediction model for recurrence after translabyrinthine surgery for vestibular schwannoma: toward personalized postoperative surveillance

Purpose

The aim of this study is to compute and validate a statistical predictive model for the risk of recurrence, defined as regrowth of tumor necessitating salvage treatment, after translabyrinthine removal of vestibular schwannomas to individualize postoperative surveillance.

Methods

The multivariable predictive model for risk of recurrence was based on retrospectively collected patient data between 1995 and 2017 at a tertiary referral center. To assess for internal validity of the prediction model tenfold cross-validation was performed. A ‘low’ calculated risk of recurrence in this study was set at < 1%, based on clinical criteria and expert opinion.

Results

A total of 596 patients with 33 recurrences (5.5%) were included for analysis. The final prediction model consisted of the predictors ‘age at time of surgery’, ‘preoperative tumor growth’ and ‘first postoperative MRI outcome’. The area under the receiver operating curve of the prediction model was 89%, with a C-index of 0.686 (95% CI 0.614–0.796) after cross-validation. The predicted probability for risk of recurrence was low (< 1%) in 373 patients (63%). The earliest recurrence in these low-risk patients was detected at 46 months after surgery.

Conclusion

This study presents a well-performing prediction model for the risk of recurrence after translabyrinthine surgery for vestibular schwannoma. The prediction model can be used to tailor the postoperative surveillance to the estimated risk of recurrence of individual patients. It seems that especially in patients with an estimated low risk of recurrence, the interval between the first and second postoperative MRI can be safely prolonged.

Risk Factors for Progression in Vestibular Schwannomas After Incomplete Resection: A Single Center Retrospective Study

Background and Purpose: The risk factors for progression in vestibular schwannomas (VSs) after incomplete resection (IR) remain to be elucidated. The purpose of this study was to investigate the risk factors for progression in remnant VSs after surgery.

Methods: From January 2009 to January 2018, 140 consecutive patients who underwent IR of VSs via suboccipital retrosigmoid approach in our institution were retrospectively analyzed. During follow-up, if progression was detected, the patient was classified into Progressive Group (PG); if the residual tumor was stable or shrank, the patient was classified into Stable Group (SG). Univariate analysis and multivariate analysis were used to evaluate the risk factors for progression after IR of VSs.

Results: After a mean follow-up of 80.4 months (range, 24–134 months), 35 (25.0%) patients (PG) had a progression, and no progression was detected in 105 (75.0%) patients (SG). The average tumor size was 36.5 ± 8.9 mm in PG and 31.0 ± 9.8 mm in SG, respectively. The residual tumor volume was 304.6 ± 443.3 mm³ in PG and 75.9 ± 60.0 mm³ in SG, respectively. Univariate analysis showed that preoperative tumor size, residual tumor volume, and irregular internal auditory canal (IAC) expansion were significantly different between the two groups, whereas gender, age, cystic component, or Ki-67 labeling index (LI) did not differ significantly between the two groups. Multivariate analysis showed residual tumor volume was the independent risk factor for progression.

Conclusions: VSs that underwent IR with larger preoperative size, greater residual tumor volume, or irregular IAC expansion may have a higher progression rate. Strict follow-up with shorter interval in these patients to detect early progression is necessary.

Value of intraoperative monitoring of the trigeminal nerve in detection of a superiorly displaced facial nerve during surgery for large vestibular schwannomas

The aim of this study was to investigate the role of trigeminal and facial nerve monitoring in the early identification of a superiorly (anterior and superior (AS)) displaced facial nerve. This prospective study included 24 patients operated for removal of large vestibular schwannomas (VS). The latencies of the electromyographic (EMG) events recorded from the trigeminal and facial nerve innervated muscles after mapping the superior surface of the tumor were analyzed. The mean latency of the recorded compound muscle action potential (CMAP) from the masseter muscle was 3.6 ± 0.5 ms and of the peripherally transmitted responses by volume conduction from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles was 4.6 ± 0.9, 4.1 ± 0.7, 3.9 ± 0.4, 4.3 ± 0.8, and 4.5 ± 0.6 ms, respectively, after trigeminal nerve stimulation in 24 (100%) patients (pattern I response). In 6 (25%) patients, the mean latency of CMAP on the masseter was 3.3 ± 0.3 ms, and the latencies of the CMAP from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles were 6.5 ± 1.3, 5.0 ± 1.5, 7.5 ± 1.3, 7.4 ± 0.6, and 7.0 ± 1.5 ms, respectively, longer than those of the peripherally transmitted responses (p = 0.002, p = 0.001, p < 0.001, and p = 0.015, respectively) indicating simultaneous stimulation of both nerves (pattern II response). All patients with this response were later confirmed to have an AS-displaced facial nerve. Recognizing the response resulting from simultaneous stimulation of both the facial and trigeminal nerves is important to help early identification of an AS-displaced facial nerve before it is visible in the surgical field and to avoid misleading information by confusing this pattern for a pure trigeminal nerve response.

Impact of extent of internal acoustic meatus tumor removal using translabyrinthine approach for acoustic neuroma surgery

Objectives

Many studies have investigated the surgical outcome and predictive factors of acoustic neuroma using different approaches. The present study focused on large tumors due to the greater likelihood of internal acoustic meatus involvement and the greater application of surgical intervention than radiosurgery. There have been no previous reports on outcomes of internal acoustic meatus tumor removal. We investigated the impact of the extent of internal acoustic meatus tumor removal using a translabyrinthine approach for large acoustic neuroma surgery and predictive factors of tumor control.

Methods

This retrospective study reviewed 104 patients with large cerebellopontine angle tumor >3 cm treated by translabyrinthine approach microsurgery. Predictive factors of postoperative facial palsy, tumor control, and extent of internal acoustic meatus tumor removal were assessed.

Results

The mean tumor size was 38.95 ± 6.83 mm. Postoperative facial function showed 76.9% acceptable function (House–Brackmann grade 1 or 2) six months after surgery. The extent of internal acoustic meatus tumor removal was a statistically significant predictor factor of poor postoperative facial function. Younger age, larger tumor size needing radiosurgery, and more extensive removal of tumor were associated with better tumor control.

Conclusion

More extensive internal acoustic meatus tumor removal was associated with poor postoperative facial function and better tumor control.

Tumor Control Following Stereotactic Radiosurgery in Patients with Vestibular Schwannomas - A Retrospective Cohort Study

BACKGROUND

To better counsel vestibular schwannoma patients, it is necessary to understand the tumor control rates of stereotactic radiosurgery (SRS).

OBJECTIVES

To determine tumor control rates, factors determining control and complication rates following SRS.

METHODS

Tertiary hospital retrospective cohort.

RESULTS

579 tumors (576 patients) were treated with SRS. 477 tumors (474 patients, 82%) had ≥1 year follow up and 60% (344) ≥3 years follow up. 88% of tumors had primary SRS and 6.7% salvage SRS. Median follow up time was 4.6 years. At 3 years, the tumor control rate of primary SRS was 89% (258 of 290) in sporadic tumors compared to 43% in Neurofibromatosis type II (3 of 17) (p < 0.01). Our bivariable survival data analysis showed that Neurofibromatosis type II, documented pre-SRS growth, tumor measured by maximum dimension, SRS given as nonprimary treatment increased hazard of failure to control. There was one case of malignancy and another of rapid change following intra-tumoral hemorrhage. For tumors undergoing surgical salvage (25 of 59), 56% had a total or near-total resection, 16% had postoperative CSF leak, with 12% new facial paralysis (House-Brackmann grade VI) and worsening of facial nerve outcomes (House-Brackmann grade worse in 59% at 12 mo).

CONCLUSIONS

Control of vestibular schwannoma after primary SRS occurs in the large majority. Salvage surgical treatment was notable for higher rates of postoperative complications compared to primary surgery reported in the literature.

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.

Optimal Volume of the Residual Tumor to Predict Long-term Tumor Control Using Stereotactic Radiosurgery after Facial Nerve-preserving Surgery for Vestibular Schwannomas

BACKGROUND

Intended subtotal resection (STR) followed by adjuvant gamma knife radiosurgery (GKRS) has emerged as an effective treatment option for facial nerve (FN) preservation in vestibular schwannomas (VSs). This study aimed to identify the optimal cut-off volume of residual VS to predict favorable outcomes in terms of both tumor control and FN preservation.

METHODS

This retrospective study assessed the patients who underwent adjuvant GKRS for residual VS after microsurgery. A total of 68 patients who had been followed up for ≥ 24 months after GKRS were included. Tumor progression was defined as an increase in tumor volume (TV) of ≥ 20%. House-Brackmann grades I and II were considered to indicate good FN function.

RESULTS

The median residual TV was 2.5 cm³ (range: 0.3-27.4). The median follow-up period after the first adjuvant GKRS was 64 months (range: 25.7-152.4). Eight (12%) patients showed tumor progression. In multivariate analyses, residual TV was associated with tumor progression (P = 0.003; hazard ratio [HR], 1.229; 95% confidence interval [CI], 1.075-1.405). A residual TV of 6.4 cm³ was identified as the cut-off volume for showing the greatest difference in progression-free survival (PFS). The 5-year PFS rates in the group with residual TVs of < 6.4 cm³ (54 patients) and that with residual TVs of ≥ 6.4 cm³ (14 patients) were 93.3% and 69.3%, respectively (P = 0.014). A good FN outcome was achieved in 57 (84%) patients. Residual TV was not associated with good FN function during the immediate postoperative period (P = 0.695; odds ratio [OR], 1.024; 95% CI, 0.908-1.156) or at the last follow-up (P = 0.755; OR, 0.980; 95% CI, 0.866-1.110).

CONCLUSION

In this study, residual TV was associated with tumor progression in VS after adjuvant GKRS following STR. As preservation of FN function is not correlated with the extent of resection, optimal volume reduction is imperative to achieve long-term tumor control. Our findings will help surgeons predict the prognosis of residual VS after FN-preserving surgery.

Evolving Role of Non-Total Resection in Management of Acoustic Neuroma in the Gamma Knife Era

OBJECTIVE

To examine patients with residual tumor after vestibular schwannoma (VS) resection with focus on need for further therapy, including stereotactic radiosurgery (SRS) and revision surgery.

STUDY DESIGN AND SETTING

Retrospective review at two tertiary otology referral centers.

PATIENTS AND INTERVENTION

Patients undergoing primary surgery for VS from 2007 to 2017.

MAIN OUTCOME MEASURE

Degree of resection and need for further treatment.

RESULTS

Of 289 patients undergoing surgery, 38 (13.1%) underwent subtotal resections (<95% of tumor resected) and 77 (26.6%) underwent near-total resections (≥95% but <100%). Patients with any residual tumor had larger tumors preoperatively (mean estimated volume 6.3 cm versus 2.1 cm, p < 0.0005) but were otherwise clinically and demographically similar to the population as a whole. Further treatment (surgery or SRS) was needed in 4.6, 14.3, and 50.0% of patients after gross total, near-total, and subtotal resections, respectively (p < 0.0005). Patients undergoing additional therapy had larger residual tumors (median post- to preoperative estimated volume ratio 0.09 versus 0.01, p < 0.0005). Patients undergoing subtotal and near-total resections had poorer facial function at ultimate follow up than those undergoing gross total resections (p = 0.001), likely due to larger tumors and more difficult resections. Literature review revealed higher rates of gross total resection as well as facial palsy in the pre-SRS era.

CONCLUSION

Residual tumor following VS resection is more common today than in the pre-SRS era. Availability of SRS may encourage leaving residual tumor intraoperatively to preserve neural structures. Current surgical strategies decrease surgical morbidity but necessitate further treatment in over 10% of cases.

Prognostic Factors for the Outcome of Translabyrinthine Surgery for Vestibular Schwannomas

OBJECTIVE

To identify predictors of tumor recurrence and postoperative facial nerve function after translabyrinthine surgery for unilateral vestibular schwannomas.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral center.

PATIENTS

Between 1996 and 2017 a total of 596 patients with unilateral vestibular schwannoma underwent translabyrinthine surgery. Pre- and postoperative clinical status, radiological, and surgical findings were evaluated.

INTERVENTIONS

Translabyrinthine surgery.

MAIN OUTCOME MEASURES

Potential predictors for tumor recurrence and facial nerve outcome were analyzed using Cox regression and ordinal logistic regression, respectively.

RESULTS

The extent of tumor removal was total in 32%, near-total in 58%, and subtotal in 10%. In 5.5% (33/596) of patients the tumor recurred. Subtotal tumor resection (p = 0.004, hazard ratios [HR] = 10.66), a young age (p = 0.008, HR = 0.96), and tumor progression preoperatively (p = 0.042, HR = 2.32) significantly increased the risk of recurrence, whereas tumor size or histologic composition did not. A good postoperative facial nerve function (House-Brackmann grade 1-2) was achieved in 85%. The risk of postoperative facial nerve paresis or paralysis increased with tumor size (p < 0.001, OR = 1.52), but was not associated with the extent of tumor removal, histologic composition, or patient demographics.

CONCLUSIONS

Translabyrinthine surgery is an effective treatment for vestibular schwannoma, with a good local control rate and facial nerve outcome. The extent of tumor removal is a clinically relevant predictor for tumor recurrence, as are young patient age and preoperative tumor progression. A large preoperative tumor size is associated with a higher risk of postoperative facial nerve paresis or paralysis.

The behavior of residual tumors following incomplete surgical resection for vestibular schwannomas

The management of vestibular schwannoma (VS) with residual tumor following incomplete resection remains controversial and little is known regarding postoperative tumor volume changes. The behavior of residual tumors was analyzed for 111 patients who underwent surgery for newly diagnosed VS between September 2006 and July 2017. The postoperative tumor volume changes were assessed during a mean follow-up of 69 months (range 36–147 months). Fifty-three patients underwent imaging surveillance following incomplete resection. There was no residual tumor growth in 44 patients (83%). A significant regression of residual tumor volume was noted in the no growth group at postoperative 1 year (p = 0.028), 2 years (p = 0.012), but not from 3 years onwards. Significant predictors of regrowth were immediate postoperative tumor volume ≥ 0.7 cm³ (HR 10.5, p = 0.020) and residual tumor location other than the internal auditory canal (IAC) (HR 6.2, p = 0.026). The mean time to regrowth was 33 months (range 5–127 months). The 2-, 5-, and 10-year regrowth-free survival rates were 90.6%, 86.8%, and 83%, respectively. In conclusion, significant residual tumor regression could occur within 2 years for a VS with an immediate postoperative tumor volume less than 0.7 cm³ or residual tumor in IAC.

EANO guideline on the diagnosis and treatment of vestibular schwannoma

The level of evidence to provide treatment recommendations for vestibular schwannoma is low compared with other intracranial neoplasms. Therefore, the vestibular schwannoma task force of the European Association of Neuro-Oncology assessed the data available in the literature and composed a set of recommendations for health care professionals. The radiological diagnosis of vestibular schwannoma is made by magnetic resonance imaging. Histological verification of the diagnosis is not always required. Current treatment options include observation, surgical resection, fractionated radiotherapy, and radiosurgery. The choice of treatment depends on clinical presentation, tumor size, and expertise of the treating center. In small tumors, observation has to be weighed against radiosurgery, in large tumors surgical decompression is mandatory, potentially followed by fractionated radiotherapy or radiosurgery. Except for bevacizumab in neurofibromatosis type 2, there is no role for pharmacotherapy.

Subtotal Resection Followed by Adjuvant Radiosurgery for Large Vestibular Schwannomas: Outcomes with Regard to the Timing and Regimen of Irradiation

OBJECTIVE

To evaluate the results of combined management of large vestibular schwannomas (VS) with initial subtotal resection (STR) followed by adjuvant stereotactic radiosurgery (SRS), with a particular emphasis on the timing and regimen of irradiation.

METHODS

Seventeen patients underwent STR of a VS followed by SRS, whereas five others were observed after STR. Early SRS (<6 months after surgery) and late SRS (>6 months after surgery) were done in 8 and 9 patients, respectively. Single- and multisession SRS treatments were administered in 10 and 7 patients, respectively. The mean follow-up durations after surgery and SRS were 40 and 28 months, respectively.

RESULTS

The rates of radiological and oncological tumor control after SRS were 82% and 100%, respectively. The tumor volume at the last follow-up and its relative changes after SRS did not differ significantly on the basis of the irradiation timing (early versus late) or on the basis of the irradiation regimen (single-session versus multisession). In no patient who was observed after STR of a VS was tumor regrowth noted during a mean follow-up period of 49 months. At 12 months after surgery, motor function of the ipsilateral facial nerve corresponded to House-Brackmann grades I, II, III, and IV in 16 patients (73%), 3 patients (14%), 1 patient (5%), and 2 patients (9%), respectively. Facial nerve function at the last follow-up did not differ significantly on the basis of the irradiation timing (early versus late) or on the basis of the irradiation regimen (single-session versus multisession).

CONCLUSION

The combination of initial STR followed by adjuvant SRS is an effective treatment strategy for patients with a large VS. Although the optimal timing and regimen of postoperative irradiation of the residual lesion should be defined further, our preliminary data suggest that either early or late SRS after surgery may provide good tumor control and optimal functional results.

Microsurgical Treatment and Follow-Up of KOOS Grade IV Vestibular Schwannoma: Therapeutic Concept and Future Perspective

Purpose

Surgery of KOOS IV vestibular schwannoma remains challenging regarding the balance of extent of tumor resection (EoR) and functional outcome. Our aim was to evaluate the outcome of surgical resection and define a cut-off value for safe resection with low risk for tumor regrowth of KOOS IV vestibular schwannoma.

Methods

All patients presenting at the authors’ institution between 2000 and 2019 with surgically treated KOOS IV vestibular schwannoma were included. Outcome measures included EoR, facial/hearing nerve function, surgical complications and progression of residual tumor during the median follow-up period of 28 months.

Results

In 58 patients, mean tumor volume was 17.1 ± 9.2 cm³, and mean EoR of 81.6 ± 16.8% could be achieved. Fifty-one patients were available for the follow-up analysis. Growth of residual tumor was observed in 11 patients (21.6%) followed by adjuvant treatment with stereotactic radiosurgery or repeat surgery in 15 patients (29.4%). Overall serviceable hearing preservation was achieved in 38 patients (74.5%) and good facial outcome at discharge was observed in 66.7% of patients, significantly increasing to 82.4% at follow-up. Independent predictors for residual tumor growth was EoR ≤ 87% (OR11.1) with a higher EoR being associated with a very low number of residual tumor progression amounting to 7.1% at follow-up (p=0.008).

Conclusions

Subtotal tumor resection is a good therapeutic concept in patients with KOOS IV vestibular schwannoma resulting in a high rate of good hearing and facial nerve function and a very low rate of subsequent tumor progression. The goal of surgery should be to achieve more than 87% of tumor resection to keep residual tumor progression low.

Surgical management for large vestibular schwannomas: a systematic review, meta-analysis, and consensus statement on behalf of the EANS skull base section

BACKGROUND AND OBJECTIVE

The optimal management of large vestibular schwannomas continues to be debated. We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of this problem from a European perspective.

MATERIAL AND METHODS

A systematic review of MEDLINE database, in compliance with the PRISMA guidelines, was performed. A subgroup analysis screening all surgical series published within the last 20 years (January 2000 to March 2020) was performed. Weighted summary rates for tumor resection, oncological control, and facial nerve preservation were determined using meta-analysis models. This data along with contemporary practice patterns were discussed within the task force to generate consensual recommendations regarding preoperative evaluations, optimal surgical strategy, and follow-up management.

RESULTS

Tumor classification grades should be systematically used in the perioperative management of patients, with large vestibular schwannomas (VS) defined as > 30 mm in the largest extrameatal diameter. Grading scales for pre- and postoperative hearing (AAO-HNS or GR) and facial nerve function (HB) are to be used for reporting functional outcome. There is a lack of consensus to support the superiority of any surgical strategy with respect to extent of resection and use of adjuvant radiosurgery. Intraoperative neuromonitoring needs to be routinely used to preserve neural function. Recommendations for postoperative clinico-radiological evaluations have been elucidated based on the surgical strategy employed.

CONCLUSION

The main goal of management of large vestibular schwannomas should focus on maintaining/improving quality of life (QoL), making every attempt at facial/cochlear nerve functional preservation while ensuring optimal oncological control, thereby allowing to meet patient expectations. Despite the fact that this analysis yielded only a few Class B evidences and mostly expert opinions, it will guide practitioners to manage these patients and form the basis for future clinical trials.

Near Total Versus Gross Total Resection of Large Vestibular Schwannomas: Facial Nerve Outcome

BACKGROUND

Large vestibular schwannomas (VSs) with brainstem compression are generally reserved for surgical resection. Surgical aggressiveness must be balanced with morbidity from cranial nerve injury. The purpose of the present investigation is to evaluate the clinical presentation, management modality, and patient outcomes following near total resection (NTR) vs gross total resection (GTR) of large VSs.

OBJECTIVE

To assess facial nerve outcome differences between GTR and NTR patient cohorts.

METHODS

Between January 2010 and March 2018, a retrospective chart review was completed to capture patients continuously who had VSs with Hannover grades T4a and T4b. NTR was decided upon intraoperatively. Primary data points were collected, including preoperative symptoms, tumor size, extent of resection, and postoperative neurological outcome.

RESULTS

A total of 37 patients underwent surgery for treatment of large and giant (grade 4a and 4b) VSs. Facial nerve integrity was preserved in 36 patients (97%) at the completion of surgery. A total of 27 patients underwent complete resection, and 10 had near total (>95%) resection. Among patients with GTR, 78% (21/27) had House-Brackmann (HB) grade I-II facial nerve function at follow-up, whereas 100% (10/10) of the group with NTR had HB grade I-II facial nerve function. Risk of meningitis, cerebrospinal fluid leak, and sinus thromboses were not statistically different between the 2 groups. There was no stroke, brainstem injury, or death. The mean follow-up was 36 mo.

CONCLUSION

NTR seems to offer a benefit in terms of facial nerve functional outcome compared to GTR in surgical management of large VSs without significant risk of recurrence.

Residual Tumor Volume and Location Predict Progression After Primary Subtotal Resection of Sporadic Vestibular Schwannomas: A Retrospective Volumetric Study

BACKGROUND

Preservation of functional integrity during vestibular schwannoma surgery has become critical in the era of patient-centric medical decision-making. Subtotal tumor removal is often necessary when dense adhesions between the tumor and critical structures are present. However, it is unclear what the rate of tumor control is after subtotal resection (STR) and what factors are associated with recurrence.

OBJECTIVE

To determine the rate of residual tumor growth after STR and identify clinical and radiographic predictors of tumor progression.

METHODS

A single-institution retrospective study was performed on all sporadic vestibular schwannomas that underwent surgical resection between January 1, 2002 and December 31, 2015. Clinical charts, pathology, radiology, and operative reports were reviewed. Volumetric analysis was performed on all pre- and postoperative MR imaging. Univariate and multivariate logistic regression was performed to identify predictors of the primary endpoint of tumor progression. Kaplan-Meier analysis was performed to compare progression free survival between 2 groups of residual tumor volumes and location.

RESULTS

In this cohort of 66 patients who underwent primary STR, 30% had documented progression within a median follow up period of 3.1 yr. Greater residual tumor volume (OR 2.0 [1.1-4.0]) and residual disease within the internal auditory canal (OR 3.7 [1.0-13.4]) predicted progression on multivariate analysis.

CONCLUSION

These longitudinal data provide insight into the behavior of residual tumor, helping clinicians to determine if and when STR is an acceptable surgical strategy and to anchor expectations during shared medical decision-making consultation with patients.

MMP-14 (MT1-MMP) Is a Biomarker of Surgical Outcome and a Potential Mediator of Hearing Loss in Patients With Vestibular Schwannomas

Improved biomarkers are needed for vestibular schwannoma (VS), the most common tumor of the cerebellopontine angle, as existing clinical biomarkers have poor predictive value. Factors such as tumor size or growth rate do not shed light on the pathophysiology of associated sensorineural hearing loss (SNHL) and suffer from low specificity and sensitivity, whereas histological markers only sample a fraction of the tumor and are difficult to ascertain before tumor treatment or surgical intervention. Proteases play diverse and critical roles in tumorigenesis and could be leveraged as a new class of VS biomarkers. Using a combination of in silico, in vitro, and ex vivo approaches, we identified matrixmetalloprotease 14 (MMP-14; also known as MT1-MMP), from a panel of candidate proteases that were differentially expressed through the largest meta-analysis of human VS transcriptomes. The abundance and proteolytic activity of MMP-14 in the plasma and tumor secretions from VS patients correlated with clinical parameters and the degree of SNHL. Further, MMP-14 plasma levels correlated with surgical outcomes such as the extent of resection. Finally, the application of MMP-14 at physiologic concentrations to cochlear explant cultures led to damage to spiral ganglion neuronal fibers and synapses, thereby providing mechanistic insight into VS-associated SNHL. Taken together, MMP-14 represents a novel molecular biomarker that merits further validation in both diagnostic and prognostic applications for VS.

Facial nerve outcomes following gamma knife radiosurgery for subtotally resected vestibular schwannomas: Early versus delayed timing of therapy

OBJECTIVES

Initially treating vestibular schwannomas (VSs) with subtotal resection (STR) followed by Gamma Knife radiosurgery (GKRS) for progression of tumor residual is a strategy that balances maximal tumor resection with preservation of neurological function. The effect of timing of GKRS for residual and recurrent VSs remains poorly defined. We developed a simple and practical treatment algorithm for the timing of GKRS after STR of VSs and reviewed our follow-up results to determine outcomes between patients treated with early vs. late GKRS.

PATIENTS AND METHODS

Patients that underwent STR between 1999 and 2017 for a VS at Tufts Medical Center were identified and included in the study cohort. Patients who received GKRS ≤ 12 months after STR were included in the early intervention group. Patients who received GKRS > 12 months after STR or did not have tumor progression on follow-up thus not requiring GKRS were included in the observation/delayed intervention group.

RESULTS

STR of VSs was performed on 23 patients. Mean patient age at the time of STR was 53.0 years (range: 20-86.2). The mean follow-up was 4.2 years (range: 1 month-15.5 years). Patients most frequently presented with hearing loss. There were 5 patients (21.7 %) in the early intervention group and 18 (78.3 %) patients in the observation/delayed intervention group. Ten of 23 patients (43.5 %) required GKRS. Thirteen (56.5 %) did not receive GKRS. None of the patients in the early intervention group or the observation/delayed intervention group had changes in House-Brackmann (HB) Grade either after GKRS or at the end of the study period.

CONCLUSIONS

GKRS of residual or recurrent tumor is safe following STR of VS and appears to carry a low risk of worsening facial nerve function when performed for progressive tumor growth.

The impact of the MIB-1 index on facial nerve outcomes in vestibular schwannoma surgery

Background

Facial nerve palsy is a severe morbid condition that occurs after vestibular schwannoma (VS) surgery. The objective of this study was to evaluate facial nerve outcomes based on surgical techniques, tumour size, and immunohistochemical factors.

Methods

One hundred eighteen patients with VS were retrospectively analysed. Gross total resection (GTR) was achieved in 83 patients, and subtotal resection (STR) was achieved in 35 patients. Follow-up was 60 months (median). Facial nerve outcomes were assessed for 24 months after surgery. Analysis of the MIB-1 index was performed in 114 patients (97%) to evaluate recurrence and facial nerve outcomes.

Results

Immediately after surgery, 16 of 35 patients (45.7%) with STR and 21 of 83 patients (25.3%) with GTR had a good (House-Brackmann (HB) score ≤ 2) facial nerve outcome (p = 0.029). Semi-sitting positioning (p = 0.002) and tumour size class of 3 (> 4 cm) were also associated with worse HB outcomes after 2 years (p = 0.004) in univariate analyses. The MIB-1 index was significantly correlated with diffuse infiltration of tumour-associated CD45⁺ lymphocytes (r = 0.63, p = 0.015) and CD68⁺ macrophages (r = 0.43, p = 0.021). ROC analysis found an AUC of 0.73 (95% CI = 0.60–0.86, p = 0.003) for the MIB-1 index in predicting poor facial nerve outcomes. Binary logistic regression analysis revealed an MIB-1 index ≥ 5% (16/28 (57.1%) vs. 5/40 (12.5%); p < 0.001, OR = 14.0, 95% CI = 3.2–61.1) and a tumour size class of 3 (6/8 (75.0%) vs. 2/8 (25.0%); p = 0.01, OR = 14.56, 95% CI = 1.9–113.4) were predictors of poor HB scores (≥ 3) after 1 year.

Conclusions

An MIB-1 index ≥ 5% seems to predict worse long-term facial nerve outcomes in VS surgery.

Prediction of vestibular schwannoma recurrence using artificial neural network

OBJECTIVES

To compare two statistical models, namely logistic regression and artificial neural network (ANN), in prediction of vestibular schwannoma (VS) recurrence.

METHODS

Seven hundred eighty-nine patients with VS diagnosis completed an online survey. Potential predictors for recurrence were derived from univariate analysis by reaching the cut off P value of .05. Those nine potential predictors were years since treatment, surgeon's specialty, resection amount, and having incomplete eye closure, dry eye, double vision, facial pain, seizure, and voice/swallowing problem as a complication following treatment. Multivariate binary logistic regression model was compared with a four-layer 9-5-10-1 feedforward backpropagation ANN for prediction of recurrence.

RESULTS

The overall recurrence rate was 14.5%. Significant predictors of recurrence in the regression model were years since treatment and resection amount (both P < .001). The regression model did not show an acceptable performance (area under the curve [AUC] = 0.64; P = .27). The regression model's sensitivity and specificity were 44% and 69%, respectively and correctly classified 56% of cases. The ANN showed a superior performance compared to the regression model (AUC = 0.79; P = .001) with higher sensitivity (61%) and specificity (81%), and correctly classified 70% of cases.

CONCLUSION

The constructed ANN model was superior to logistic regression in predicting patient-answered VS recurrence in an anonymous survey with higher sensitivity and specificity. Since artificial intelligence tools such as neural networks can have higher predictive abilities compared to logistic regression models, continuous investigation into their utility as complementary clinical tools in predicting certain surgical outcomes is warranted.

Exclusive surgical treatment for vestibular schwannoma regrowth or recurrence: A meta-analysis of the literature

Vestibular schwannomas can be treated in different ways, but for symptomatic or growing tumors, the gold standard is surgical removal of the lesion. In order to preserve neurovascular structures, partial removal is often performed, leaving a residual that may grow in subsequent years. To date, there is no consensus with regard to surgical treatment of vestibular schwannoma residuals, and so this review focuses on this topic. A structured search was performed on PubMed searching for all articles discussing vestibular schwannoma residuals and recurrences. Only articles discussing surgical treatment were included, focusing on studies which also examined facial nerve outcomes. A total of 51 articles were eligible for review and these included 375 patients. Statistical analysis was performed by correlating the following parameters: patients' gender and age at first surgery, surgical approach adopted at first and subsequent surgeries, tumor and residual size, and extent of resection (gross total, near total, subtotal or others) at first and subsequent surgical procedures. Facial nerve function was also analyzed focusing on its performance when correlated with the different surgical approaches. The data were analyzed by linear regression but there were no correlations between any of the parameters chosen. There was a statistically significant difference between the first approach used (mainly the retrosigmoid route) compared with subsequent approaches (mainly the translabyrinthine route). In total, 8.5 % of patients needed further treatment due to residual regrowth. Facial nerve outcome was independent of the parameters chosen. Exclusive surgical treatment for vestibular schwannoma residuals had a very low failure rate in terms of requiring further treatment. The approach usually chosen for second surgery was the translabyrinthine technique, and this may be explained by the location of the residual, rather than its size. The choice of a particular surgical approach rather than another had no influence on facial nerve function. Complications rates are comparable to Gamma Knife Radiosurgery's as reported in the literature.

Intended Near-Total Removal of Koos Grade IV Vestibular Schwannomas: Reconsidering the Treatment Paradigm

BACKGROUND

The goals of treating Koos grade IV vestibular schwannomas are to relieve brainstem compression, preserve or restore neurological function, and achieve long-term tumor control while minimizing tumor- and treatment-related morbidity.

OBJECTIVE

To propose a treatment paradigm involving the intentional near-total removal of Koos grade IV vestibular schwannomas, in which a small amount of residual tumor is not dissected off the cisternal portion of the facial nerve. Patients are then followed by a wait-and-scan approach. Any subsequent volumetric progression of the residual tumor is treated with radiosurgery.

METHODS

This is a case series of 44 consecutive unselected patients who underwent intended near-total resection of a Koos grade IV vestibular schwannoma through a retrosigmoid approach from January 2009 to December 2015. Pre- and postoperative volumetric analyses were performed on routine magnetic resonance imaging sequences (constructive interference in steady state and gadolinium-enhanced T1-weighted sequence).

RESULTS

The mean preoperative tumor volume was 10.9 cm3. The mean extent of resection was 89%. At the last clinical follow-up, facial nerve function was good [House and Brackmann (HB) I-II] in 89%, fair (HB III) in 9%, and poor (HB IV-VI) in 2% of the patients. At the last radiological follow-up, the residual tumor had become smaller or remained the same size in 84% of patients. Volumetric progression was negatively correlated with the original extent of resection and positively correlated with postoperative residual tumor volume (P = .01, P < .001, respectively).

CONCLUSION

Intended near-total removal results in excellent preservation of facial nerve function and has a low recurrence rate. Any progressive residual tumor may be treated by radiosurgery.

Ki-67 index as a predictor of vestibular schwannoma regrowth or recurrence

BACKGROUND

Ki-67 is a monoclonal antibody that provides a means of evaluating the growth fraction of normal and neoplastic human cell populations. A Ki-67 index of less than 3 per cent is expected for a typical schwannoma. Vestibular schwannomas with an index of greater than 3 per cent are presumed to be actively proliferating and pose a theoretically higher risk for regrowth or recurrence.

METHODS

A retrospective chart review was conducted. Ki-67 staining was performed and specimens were divided into two groups according to Ki-67 activity: less than 3 per cent (low index), and 3 per cent or greater (elevated index).

RESULTS

Eight patients (53.3 per cent) with elevated Ki-67 had recurrence or regrowth, versus five (8.5 per cent) in the low Ki-67 group. Among the 13 patients with recurrence or regrowth, the average Ki-67 value was 4.3 per cent. Among the 61 patients without recurrence or regrowth, the average Ki-67 value was 1.0 per cent.

CONCLUSION

The Ki-67 labelling index reliably identifies vestibular schwannomas with an elevated potential for recurrence or regrowth in subtotal or total resection cases. In patients with a Ki-67 index greater than 3 per cent, more frequent clinical examination and radiological follow up are recommended.

Intentional Subtotal Resection of Vestibular Schwannoma: A Reexamination

Background  Treatment of vestibular schwannomas (VS) remains controversial. Historical surgical series prioritized gross total resections (GTR); however, near total resections (NTR) and intentional subtotal resections (STR) aiming at improving cranial nerve outcomes are becoming more popular. Objective  The main purpose of this article is to assess the tumor control and facial nerve outcomes in VS patients treated with STR or NTR. Methods  VS patients undergoing STR or NTR at our institution between 1984 and 2016 were retrospectively reviewed. Patient demographics, extent of tumor resection, facial nerve injury, tumor recurrence, and need for Gamma Knife radiosurgery were analyzed. Facial nerve outcomes were quantified using House-Brackmann (HB) scores. Tumor regrowth was defined by the San Francisco criteria. Results  Four-hundred fifty-seven VS resections were performed in a 32-year period. Sixty cases met inclusion criteria. The mean (range) follow-up duration was 30.9 (12-103) months. The STR cohort ( n  = 33) demonstrated regrowth in 12 patients (36.3%) at an average of 23.6 months. The NTR cohort ( n  = 27) did not experience tumor recurrence. Risk of tumor recurrence was positively correlated with preoperative tumor size ( p  = 0.002), size of residual tumor ( p  < 0.001), and STR ( p  < 0.001). Facial nerve outcomes of HB1-2 were observed in the majority of patients in both cohorts (74.1% NTR, 56% STR), though NTR was associated with a higher likelihood of facial nerve recovery ( p  = 0.003). Conclusion  GTR remains the gold standard as long as facial nerve outcomes remain acceptable. NTR achieved superior tumor control and higher likelihood of facial nerve recovery compared with STR.