A Matched Cohort Comparison of Facial Nerve Outcomes in Salvage Surgery after Stereotactic Radiosurgery for Progressive Vestibular Schwannomas Compared with Microsurgery Alone

OBJECTIVE A randomized trial that compares clinical outcomes following microsurgery (MS) or stereotactic radiosurgery (SRS) for patients with small- and medium-sized vestibular schwannomas (VSs) is impractical, but would have important implications for clinical decision making. A matched cohort analysis was conducted to evaluate clinical outcomes in patients treated with MS or SRS. METHODS The records of 399 VS patients who were cared for by 2 neurosurgeons and 1 neurotologist between 2001 and 2014 were evaluated. From this data set, 3 retrospective matched cohorts were created to compare hearing preservation (21 matched pairs), facial nerve preservation (83 matched pairs), intervention-free survival, and complication rates (85 matched pairs) between cases managed with SRS and patients managed with MS. Cases were matched for age at surgery (± 10 years) and lesion size (± 0.1 cm). To compare hearing outcomes, cases were additionally matched for preoperative Class A hearing according to the American Academy of Otolaryngology-Head and Neck Surgery guidelines. To compare facial nerve (i.e., cranial nerve [CN] VII) outcomes, cases were additionally matched for preoperative House-Brackmann (HB) score. Investigators who were not involved with patient care reviewed the clinical and imaging records. The reported outcomes were as assessed at the time of the last follow-up, unless otherwise stated. RESULTS The preservation of preoperative Class A hearing status was achieved in 14.3% of MS cases compared with 42.9% of SRS cases (OR 4.5; p < 0.05) after an average follow-up interval of 43.7 months and 30.3 months, respectively. Serviceable hearing was preserved in 42.8% of MS cases compared with 85.7% of SRS cases (OR 8.0; p < 0.01). The rates of postoperative CN VII dysfunction were low for both groups, although significantly higher in the MS group (HB III–IV 11% vs 0% for SRS; OR 21.3; p < 0.01) at a median follow-up interval of 35.7 and 19.0 months for MS and SRS, respectively. There was no difference in the need for subsequent intervention (2 MS patients and 2 SRS patients). CONCLUSIONS At this high-volume center, VS resection or radiosurgery for tumors ≤ 2.8 cm in diameter was associated with low overall morbidity. The need for subsequent intervention was the same in both groups. SRS was associated with improved hearing and facial preservation rates and reduced morbidity, but with a shorter average follow-up period. Facial function was excellent in both groups. Since patients were not randomly selected for surgery, different clinical outcomes may be of different value to individual patients. Both anticipated medical outcomes and patient goals remain the drivers of treatment decisions.

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Resection of vestibular schwannomas after stereotactic radiosurgery: a systematic review

Journal of Neurosurgery ◽

10.3171/2020.7.jns2044 ◽

2020 ◽

pp. 1-9

Author(s):

Max Whitmeyer ◽

Bledi C. Brahimaj ◽

André Beer-Furlan ◽

Sameer Alvi ◽

Madeline J. Epsten ◽

...

Keyword(s):

Tumor Growth ◽

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Surgical Approach ◽

Salvage Surgery ◽

Vestibular Schwannomas ◽

Cochrane Library ◽

Nerve Preservation ◽

Facial Nerve Preservation ◽

Primary Indication

OBJECTIVEMultiple short series have evaluated the efficacy of salvage microsurgery (MS) after stereotactic radiosurgery (SRS) for treatment of vestibular schwannomas (VSs); however, there is a lack of a large volume of patient data available for interpretation and clinical adaptation. The goal of this study was to provide a comprehensive review of tumor characteristics, management, and surgical outcomes of salvage of MS after SRS for VS.METHODSThe Medline/PubMed, Scopus, CINAHL, Cochrane Library, and Google Scholar databases were queried according to PRISMA guidelines. All English-language and translated publications were included. Studies lacking adequate study characteristics and outcomes were excluded. Cases involving neurofibromatosis type 2, previous MS, or malignant transformation were excluded when possible.RESULTSTwenty studies containing 297 cases met inclusion criteria. Three additional cases from Rush University Medical Center were added for 300 total cases. Tumor growth with or without symptoms was the primary indication for salvage surgery (92.3% of cases), followed by worsening of symptoms without growth (4.6%) and cystic enlargement (3.1%). The average time to MS after SRS was 39.4 months. The average size and volume of tumor at surgery were 2.44 cm and 5.92 cm3, respectively. The surgical approach was retrosigmoid (42.8%) and translabyrinthine (57.2%); 59.5% of patients had a House-Brackmann (HB) grade of I or II. The facial nerve was preserved in 91.5% of cases. Facial nerve preservation and HB grades were lower for the translabyrinthine versus retrosigmoid approach (p = 0.31 and p = 0.18, respectively); however, fewer complications were noted in the translabyrinthine approach (p = 0.29). Gross-total resection (GTR) was completed in 55.7% of surgeries. Studies that predominantly used subtotal resection (STR) were associated with a lower rate of facial nerve injury (5.3% vs 11.3%, p = 0.07) and higher rate of HB grade I or II (72.9% vs 48.0%, p = 0.00003) versus those using predominantly GTR. However, majority STR was associated with a recurrence rate of 3.6% as compared to 1.4% for majority GTR (p = 0.29).CONCLUSIONSThis study showed that the leading cause of MS after SRS was tumor growth at an average of 39.4 months after radiation. There were no significant differences in outcomes of facial nerve preservation, postoperative HB grade, or complication rate based on surgical approach. Patients who underwent STR showed statistically significant better HB outcomes compared with GTR. MS after SRS was considered by most authors to be more difficult than primary MS. These data support the notion that the surgical goals of salvage surgery are debulking of tumor mass, decreasing compression of the brainstem, and not necessarily pursuing GTR.

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322 Rate of Residual Tumor Growth After Primary Subtotal Resection (STR) and the Role of Upfront Versus Salvage Stereotactic Radiosurgery (SRS) for Sporadic Vestibular Schwannomas

Neurosurgery ◽

10.1093/neuros/nyx417.322 ◽

2017 ◽

Vol 64 (CN_suppl_1) ◽

pp. 270-270

Author(s):

Jonathan D Breshears ◽

Carlene Partow ◽

Tarik Tihan ◽

Michael William McDermott ◽

Patricia Sneed ◽

...

Keyword(s):

Tumor Growth ◽

Stereotactic Radiosurgery ◽

Gamma Knife ◽

Salvage Surgery ◽

Residual Tumor ◽

Salvage Treatment ◽

Vestibular Schwannomas ◽

Subtotal Resection

Abstract INTRODUCTION Maximal safe resection is an optimal surgical strategy for moderate-to-large vestibular schwannomas, however data on the long-term outcomes of residual tumor after STR is lacking. The goal of this study was to review our rates of residual tumor growth, and the control rates of salvage versus upfront stereotactic radiosurgery (SRS). METHODS This retrospective single-institution study included all sporadic vestibular schwannomas treated primarily with STR at our institution from 2002 2015. The primary outcome was tumor growth requiring salvage treatment, and response to salvage treatment (surgery or SRS). Patients treated with upfront SRS after surgery were analyzed separately. RESULTS >295 patients underwent primary surgery for a vestibular schwannoma between 2002 - 2015, including 140 STRs. 49 cases with <1 year follow-up were excluded. 17 cases received upfront SRS after surgery (12 Gamma Knife, 12Gy; 5 CyberKnife, 25Gy in 5 fractions), with 2 failures requiring salvage surgery at 1.6 and 2.6 years (88% control rate at 1.8 years). Seventy-four residual tumors were managed with observation after STR. 57 (77%) remained stable at a median 4.1 years. 17 tumors (23%) progressed, requiring salvage treatment at a median of 2.8 years. Eleven received Gamma Knife (12.5 Gy) with a 100% control rate 2.3 years after SRS. One received Cyber Knife (18Gy, 3 fractions), ultimately requiring repeat surgery 3 years later. 4 residual tumors received salvage surgery at a median interval of 5 years after STR, and one was lost to follow-up. The control rate of salvage SRS was 92% at 2.3 years median follow-up. CONCLUSION A majority (77%) of residual vestibular schwannomas remained stable after a primary STR. Both upfront and salvage SRS had good control rates (∼90%) in our series. Further study is needed to define the role of upfront versus salvage SRS after a primary STR.

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RADT-16. HYPOFRACTIONATED RADIOTHERAPY AND STEREOTACTIC RADIOSURGERY FOR VESTIBULAR SCHWANNOMAS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Neuro-Oncology ◽

10.1093/neuonc/noaa215.769 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii184-ii185

Author(s):

Umberto Tosi ◽

Sergio Guadix ◽

Anjile An ◽

Drew Wright ◽

Andrew Brandmaier ◽

...

Keyword(s):

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Cranial Nerve ◽

Meta Analysis ◽

Post Treatment ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Significant Heterogeneity ◽

Ovid Medline ◽

Cochrane Reviews

Abstract BACKGROUND Vestibular schwannomas (VS) are tumors of the cerebellopontine angle with significant morbidity, causing hearing loss, tinnitus, and trigeminal and facial nerve compromise. Surgical resection is complex and often results in comorbidities, with radiation therapy being used to achieve tumor control. Both single dose stereotactic radiosurgery (SRS) and, in recent years, hypofractionated stereotactic radiotherapy (hSRT), where a total 18-25 Gy dose is given in approximately 3-5 fractions, have been utilized. It remains unclear, however, how each of these approaches fares compared to the other. METHODS Ovid MEDLINE, EMBASE, CINAHL, and Cochrane Reviews were searched for studies either comparing hSRT with SRS or focusing on hSRT alone for the treatment of VS. Primary endpoints included tumor control, serviceable hearing, presence of tinnitus, and facial and trigeminal nerve symptoms. A random effects analysis was employed to compare pre- and post-treatment effects (hSRT alone) or SRS and hSRT outcomes (two-arm studies). RESULTS This analysis included 21 studies focusing on hSRT alone and 13 studies comparing SRS and hSRT. Significant heterogeneity was observed. Overall, when hSRT was analyzed alone, crude tumor control was achieved in 93% of 1571 patients at average follow-up of 49.9 months. There was no difference intra-group between pre- and post-treatment odds ratios (OR) of tinnitus, facial, or trigeminal impairment. However, serviceable hearing was diminished following hSRT (OR = 0.60, 95% CI: 0.44, 0.83, p = 0.002). Comparison with SRS showed no difference with respect to tumor control (p = 0.84), serviceable hearing (p = 0.65), trigeminal impairment (p = 0.96), or facial nerve impairment (p = 0.32). CONCLUSIONS hSRT achieved excellent tumor control and, with the exception of serviceable hearing, did not result in worse cranial nerve symptomatology. Analyzing two-arm studies showed that hSRT is a treatment modality comparable to SRS with respect to tumor control and cranial nerve comorbidities.

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Dosimetric Analysis of Neural and Vascular Structures in Skull Base Tumors Treated with Stereotactic Radiosurgery

Otolaryngology ◽

10.1177/0194599817691452 ◽

2017 ◽

Vol 156 (5) ◽

pp. 857-862

Author(s):

Yarah M. Haidar ◽

Jay M. Bhatt ◽

Yaser Ghavami ◽

Omid Moshtaghi ◽

Amanda Schwer ◽

...

Keyword(s):

Carotid Artery ◽

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Trigeminal Nerve ◽

Tumor Volume ◽

Case Series ◽

Vestibular Schwannomas ◽

Anterior Inferior Cerebellar Artery ◽

Cerebellar Artery ◽

Neurovascular Structures

Objective To examine the relationship between the prescribed target dose and the dose to healthy neurovascular structures in patients with vestibular schwannomas treated with stereotactic radiosurgery (SRS). Study Design Case series with chart review. Setting SRS center from 2011 to 2013. Subjects Twenty patients with vestibular schwannomas treated at the center from 2011 to 2013. Methods Twenty patients with vestibular schwannomas were included. The average radiation dose delivered to healthy neurovascular structures (eg, carotid artery, basilar artery, facial nerve, trigeminal nerve, and cochlea) was analyzed. Results Twenty patients with vestibular schwannomas who were treated with fused computed tomography/magnetic resonance imaging–guided SRS were included in the study. The prescribed dose ranged from 10.58 to 17.40 Gy over 1 to 3 hypofractions to cover 95% of the target tumor volume. The mean dose to the carotid artery was 5.66 Gy (95% confidence interval [CI], 4.53-6.80 Gy), anterior inferior cerebellar artery was 8.70 Gy (95% CI, 4.54-12.86 Gy), intratemporal facial nerve was 3.76 Gy (95% CI, 3.04-4.08 Gy), trigeminal nerve was 5.21 Gy (95% CI, 3.31-7.11 Gy), and the cochlea was 8.70 Gy (95% CI, 7.81-9.59 Gy). Conclusions SRS for certain vestibular schwannomas can expose the anterior inferior cerebellar artery (AICA) and carotid artery to radiation doses that can potentially initiate atherosclerotic processes. The higher doses to the AICA and carotid artery correlated with increasing tumor volume. The dose delivered to other structures such as the cochlea and intratemporal facial nerve appears to be lower and much less likely to cause immediate complications when shielded.

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Outcomes of Stereotactic Radiosurgery for Large Vestibular Schwannomas: a Systematic Review and Meta-Analysis

Neuro-Oncology Practice ◽

10.1093/nop/npab011 ◽

2021 ◽

Author(s):

Umberto Tosi ◽

Miguel E Tusa Lavieri ◽

Anjile An ◽

Omri Maayan ◽

Sergio W Guadix ◽

...

Keyword(s):

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Cranial Nerve ◽

Meta Analysis ◽

Management Strategies ◽

Treatment Protocol ◽

Vestibular Schwannomas ◽

Treatment Modalities ◽

Tumor Control ◽

Pre Treatment

Abstract Background Large vestibular schwannomas (VS) pose a treatment challenge for both microsurgery (MS) and stereotactic radiosurgery (SRS). Technical developments have allowed for safer irradiation of large tumors. It remains unclear if SRS can achieve appropriate tumor control and acceptable cranial nerve toxicities. In this study, we assess outcomes of irradiation for large VS. Methods PubMed MEDLINE, EMBASE, Web of Science, and Cochrane were searched for all the studies assessing SRS outcome in large VS. Primary endpoints included clinical and radiographic tumor control, need for salvage surgery, serviceable hearing, cranial nerve V and VII impairment, presence of hydrocephalus requiring shunting, and presence of vertigo / dizziness. Results 22 studies were identified that met selection criteria for analysis from an initial pool of 1272 reports. They were evaluated according to treatment protocol: (i) single dose SRS (13 studies, 483 patients), (ii) combination of MS and SRS (7 studies, 182 patients), and (iii) fractionated SRS (3 studies, 82 patients). Tumor control was achieved in 89%, 94%, and 91% of patients, respectively. Odds ratio of post- over pre-treatment serviceable hearing were 0.42 (p < 0.01), 0.47 (p = 0.05), and 0.60 (p = 0.22); for facial nerve impairment, these OR were 1.08 (p = 0.69), 3.45 (p = 0.28), and 0.87 (p = 0.71) respectively. Conclusions The management of large VS remains challenging. All treatment modalities resulted in high tumor control rates and worsening of pre-treatment hearing. None, however, caused significant facial nerve impairment, suggesting that management strategies incorporating focal irradiation can be successful.

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Surgery After Primary Radiation Treatment for Sporadic Vestibular Schwannomas: Case Series

Operative Neurosurgery ◽

10.1093/ons/opx023 ◽

2017 ◽

Vol 13 (4) ◽

pp. 441-447 ◽

Cited By ~ 4

Author(s):

Jonathan D. Breshears ◽

Joseph A. Osorio ◽

Steven W. Cheung ◽

Igor J. Barani ◽

Philip V. Theodosopoulos

Keyword(s):

Facial Nerve ◽

Surgical Resection ◽

Radiation Treatment ◽

Salvage Surgery ◽

Case Series ◽

Technical Difficulty ◽

Vestibular Schwannomas ◽

Primary Radiation ◽

Subtotal Resection ◽

Total Resection

Abstract BACKGROUND: As radiation has become an increasingly popular primary treatment option for sporadic vestibular schwannomas, there is a minority of tumors that do not respond favorably to radiation. Data on repeat radiosurgery are emerging, and salvage surgery has been associated with increased technical difficulty and poor facial nerve outcomes. OBJECTIVE: To review the current literature and report our results with surgical resection of sporadic vestibular schwannomas that have failed primary radiation treatment. METHODS: This is a retrospective, single-surgeon case series of patients with sporadic vestibular schwannomas who failed primary radiation treatment and underwent subsequent surgical resection. We analyze demographics, clinical information, and intraoperative findings, focusing on facial nerve functional outcomes and extent of resection. RESULTS: Between 2006 and 2015, 10 patients with sporadic vestibular schwannomas whose only prior treatment was radiation underwent microsurgical resection. Eight of 10 patients had a postoperative House-Brackmann score of 1 at a median follow-up of 14 months, while 2 patients had House-Brackmann score of 4. Gross total resection was achieved in 7 of 10 cases. Near total resection was achieved in 2 cases, and only subtotal resection was achieved in 1 case. CONCLUSION: Salvage surgery is a safe and effective option after failure of primary radiation and may offer benefits over repeat radiosurgery.

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Repeat stereotactic radiosurgery for progressive vestibular schwannomas after previous radiosurgery: a systematic review and meta-analysis

Neurosurgical Review ◽

10.1007/s10143-021-01528-y ◽

2021 ◽

Author(s):

Anne Balossier ◽

Jean Régis ◽

Nicolas Reyns ◽

Pierre-Hugues Roche ◽

Roy Thomas Daniel ◽

...

Keyword(s):

Systematic Review ◽

Hearing Loss ◽

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Cranial Nerve ◽

Meta Analysis ◽

Cranial Nerves ◽

Vestibular Schwannomas ◽

Benign Tumors ◽

Tumor Control

AbstractVestibular schwannomas (VS) are slow-growing intracranial extraaxial benign tumors, developing from the vestibular part of the eight cranial nerves. Stereotactic radiosurgery (SRS) has now a long-term scientific track record as first intention treatment for small- to medium-sized VS. Though its success rate is very high, SRS for VS might fail to control tumor growth in some cases. However, the literature on repeat SRS after previously failed SRS remains scarce and reported in a low number of series with a limited number of cases. Here, we aimed at performing a systematic review and meta-analysis of the literature on repeat SRS for VS. Using PRISMA guidelines, we reviewed manuscripts published between January 1990 and October 2020 and referenced in PubMed. Tumor control and cranial nerve outcomes were evaluated with separate meta-analyses. Eight studies comprising 194 patients were included. The overall rate of patients treated in repeat SRS series as per overall series with first SRS was 2.2% (range 1.2–3.2%, p < 0.001). The mean time between first and second SRS was 50.7 months (median 51, range 44–64). The median marginal dose prescribed at first SRS was 12 Gy (range 8–24) and at second SRS was 12 Gy (range 9.8–19). After repeat SRS, tumor stability was reported in 61/194 patients, i.e., a rate of 29.6% (range 20.2–39%, I2 = 49.1%, p < 0.001). Tumor decrease was reported in 83/194 patients, i.e., a rate of 54.4% (range 33.7–75.1%, I2 = 89.1%, p < 0.001). Tumor progression was reported in 50/188 patients, i.e., a rate of 16.1% (range 2.5–29.7%, I2 = 87.1%, p = 0.02), rarely managed surgically. New trigeminal numbness was reported in 27/170 patients, i.e., a rate of 9.9% (range 1.4–18.3%, p < 0.02). New facial nerve palsy of worsened of previous was reported in 8/183 patients, i.e., a rate of 4.3% (range 1.4–7.2%, p = 0.004). Hearing loss was reported in 12/22 patients, i.e., a rate of 54.3% (range 24.8–83.8%, I2 = 70.7%, p < 0.001). Repeat SRS after previously failed SRS for VS is associated with high tumor control rates. Cranial nerve outcomes remain favorable, particularly for facial nerve. The rate of hearing loss appears similar to the one related to first SRS.

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Gamma Knife Radiosurgery for Large Vestibular Schwannomas: A Canadian Experience

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100014281 ◽

2013 ◽

Vol 40 (3) ◽

pp. 342-347 ◽

Cited By ~ 17

Author(s):

F. A. Zeiler ◽

M. Bigder ◽

A. Kaufmann ◽

P. J. McDonald ◽

D. Fewer ◽

...

Keyword(s):

Facial Nerve ◽

Stereotactic Radiosurgery ◽

Gamma Knife ◽

Gamma Knife Radiosurgery ◽

Hearing Preservation ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Complication Rates ◽

Maximal Diameter

Object:To review our institutional experience with Gamma Knife (GK) stereotactic radiosurgery in treating large vestibular schwannomas (VS) of 3 to 4 cm diameter.Methods:We conducted a retrospective cohort review of all patients treated with GK for VS at our institution between November 2003 and March 2012. Data on age, sex, VS volume, location and maximal diameter, House-Brackmann (HB) facial nerve scores pre and post-GK, Gardner-Robertson (GR) hearing score pre and post-GK, GK treatment parameters, VS response time, complications and clinical outcome was recorded.Results:A total of 28 patients during the defined time period were identified. Three patients were lost to follow-up. Mean follow-up was 34.5 months. Tumor control occurred in 92%, and was maintained in 85.7% at two years. Facial nerve or hearing preservation occurred in all treated compared to pre-GK status, as per HB and GR grading. Transient complications occurred in 80%. Temporary vestibular dysfunction occurred in seven patients (28%). One patient (4%) had the permanent complication of worsening pre-GK hemifacial spasm. Four patients (16%) developed hydrocephalus post-GK.Conclusion:GK stereotactic radiosurgery as a primary treatment modality for large VS can provide acceptable tumor control rates with good facial nerve and hearing preservation, and low complication rates.

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