Use of supramaximal stimulation to predict facial nerve outcomes following vestibular schwannoma microsurgery: results from a decade of experience

2013 ◽  
Vol 118 (1) ◽  
pp. 206-212 ◽  
Author(s):  
William R. Schmitt ◽  
Jasper R. Daube ◽  
Matthew L. Carlson ◽  
Jayawant N. Mandrekar ◽  
Charles W. Beatty ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Tumor Resection ◽  
Constant Current ◽  
Tumor Diameter ◽  
Facial Weakness ◽  
Tumor Removal ◽  
Supramaximal Stimulation ◽  
Facial Function

Object The goal of vestibular schwannoma surgery is tumor removal and preservation of neural function. Intraoperative facial nerve (FN) monitoring has emerged as the standard of care, but its role in predicting long-term facial function remains a matter of debate. The present report seeks to describe and critically assess the value of applying current at supramaximal levels in an effort to identify patients destined for permanent facial paralysis. Methods Over more than a decade, the protocol for stimulating and assessing the FN during vestibular schwannoma surgery at the authors' institution has consisted of applying pulsed constant-current stimulation at supramaximal levels proximally and distally following tumor resection to generate an amplitude ratio, which subtracted from 100% yields the degree to which the functional integrity of the FN “dropped off” intraoperatively. These data were prospectively collected and additional variables that might impact postoperative FN function were retrospectively reviewed from the medical record. Only patients with anatomically intact FNs and > 12 months of follow-up data were analyzed. Results There were 267 patients available for review. The average posterior fossa tumor diameter was 24 mm and the rate of long-term good (House-Brackmann Grade I–II) FN function was 84%. Univariate logistic regression analysis revealed that prior treatment, neurofibromatosis Type 2 status, tumor size, cerebellopontine angle extension, subjectively thinned FN at the time of operation, minimal stimulation threshold, percent dropoff by supramaximal stimulation (SMS), and postoperative FN function all correlated statistically (p < 0.05) with long-term FN function. When evaluating patients with significant FN weakness at the time of hospital discharge, only the percent dropoff by SMS remained a significant predictor of long-term FN function. However, the positive predictive value of SMS for long-term weakness is low, at 46%. Conclusions In a large cohort of patients, the authors found that interrogating intraoperative FN function with SMS is safe and technically simple. It is useful for predicting which patients will ultimately have good facial function, but is very limited in identifying patients destined for long-term facial weakness. This test may prove helpful in the future in tailoring less than gross-total tumor removal to limit postoperative facial weakness.

scholarly journals Impact of Motor-Evoked Potential Monitoring on Facial Nerve Outcomes after Vestibular Schwannoma Resection

2018 ◽  
Vol 128 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Kareem O. Tawfik ◽  
Zoe A. Walters ◽  
Gavriel D. Kohlberg ◽  
Noga Lipschitz ◽  
Joseph T. Breen ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Predictive Value ◽  
Evoked Potential ◽  
Amplitude Ratio ◽  
Motor Evoked Potential ◽  
Level Of Evidence ◽  
Facial Function

Objectives: Assess the utility of intraoperative transcranial facial motor-evoked potential (FMEP) monitoring in predicting and improving facial function after vestibular schwannoma (VS) resection. Study Design: Retrospective chart review. Methods: Data were obtained from 82 consecutive VS resections meeting inclusion criteria. Sixty-two cases were performed without FMEP and 20 with FMEP. Degradation of FMEP response was defined as a final-to-baseline amplitude ratio of 0.5 or less. House-Brackmann (HB) grade was assessed preoperatively, postoperatively, at follow-up assessments, and it was compared between pre- and post-FMEP cohorts. Positive predictive value (PPV) and negative predictive value (NPV), sensitivity, and specificity of FMEP degradation in predicting facial weakness were calculated. Results: In the pre-FMEP group, at length of follow-up (LOF) ⩾9 months, 83.9% (52/62) of patients exhibited HB 1-2 outcome. In the post-FMEP cohort, 75.0% (15/20) exhibited HB 1-2 function at LOF ⩾9 months. There was no difference in rates of HB 1-2 outcomes between groups in the immediate postoperative period ( P = .35) or at long-term follow-up ( P = 1.0). With respect to predicting immediate postoperative facial function, FMEP demonstrated high specificity (88.9%) and moderate sensitivity (54.5%). The PPV and NPV for immediate postoperative facial function were 85.7% and 61.5%, respectively. With respect to long-term (⩾9 months LOF) facial function, intraoperative FMEP was moderately sensitive (71.4%) and highly specific (84.6%); PPV was moderate (71.4%), and NPV was high (84.6%). Conclusions: Intraoperative FMEP is highly specific and moderately sensitive in predicting postoperative facial function for patients undergoing VS resection, but its use may not be associated with improved facial nerve outcomes. Level of Evidence: 4

Facial Nerve Outcomes After Vestibular Schwannoma Microsurgical Resection in Neurofibromatosis Type 2

2020 ◽  
pp. 019459982095414
Author(s):  
Catherine Sobieski ◽  
Daniel E. Killeen ◽  
Samuel L. Barnett ◽  
Bruce E. Mickey ◽  
Jacob B. Hunter ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Tumor Volume ◽  
Tumor Resection ◽  
Neurofibromatosis Type ◽  
Neurofibromatosis Type 2 ◽  
Tumor Diameter ◽  
Microsurgical Resection

Objective The aim of this study is to investigate facial nerve outcomes after microsurgical resection in neurofibromatosis type 2 (NF2) compared to sporadic tumors. Study Design Single institutional retrospective chart review. Setting Tertiary referral center. Methods All adult patients with NF2 vestibular schwannoma (VS) or sporadic VS who underwent microsurgical resection from 2008 to 2019 with preoperative magnetic resonance imaging (MRI) and 1 year of postsurgical follow-up were included. The primary outcome measure was postoperative House-Brackmann (HB) facial nerve score measured at first postoperative visit and after at least 10 months. Results In total, 161 sporadic VSs and 14 NF2 VSs met inclusion criteria. Both median tumor diameter (NF2, 33.5 mm vs sporadic, 24 mm, P = .0011) and median tumor volume (NF2, 12.4 cm3 vs sporadic, 2.9 cm3, P = .0005) were significantly greater in patients with NF2. The median follow-up was 24.9 months (range, 12-130.1). Median facial nerve function after 1 year for patients with NF2 was HB 3 (range, 1-6) compared to HB 1 (range, 1-6) for sporadic VS ( P = .001). With multivariate logistic regression, NF2 tumors (odds ratio [OR] = 13.9, P = .001) and tumor volume ≥3 cm3 (OR = 3.6, P = .025) were significantly associated with HB ≥3 when controlling for age, sex, extent of tumor resection, translabyrinthine approach, and prior radiation. Conclusion Tumor volume >3 cm3 and NF2 tumors are associated with poorer facial nerve outcomes 1 year following microsurgical resection.

scholarly journals Long-Term Facial Nerve Outcomes after Microsurgical Resection of Vestibular Schwannomas in Patients with Preoperative Facial Nerve Palsy

2017 ◽  
Vol 79 (03) ◽  
pp. 309-313 ◽  
Author(s):  
Michael Mooney ◽  
Benjamin Hendricks ◽  
Christina Sarris ◽  
Robert Spetzler ◽  
Randall Porter ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Nerve Palsy ◽  
Facial Nerve Palsy ◽  
Tumor Diameter ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Microsurgical Resection ◽  
Grade Iii

Objectives This study aimed at evaluating facial nerve outcomes in vestibular schwannoma patients presenting with preoperative facial nerve palsy. Design A retrospective review. Setting Single-institution cohort. Participants Overall, 368 consecutive patients underwent vestibular schwannoma resection. Patients with prior microsurgery or radiosurgery were excluded. Main Outcome Measures Incidence, House–Brackmann grade. Results Of 368 patients, 9 had confirmed preoperative facial nerve dysfunction not caused by prior treatment, for an estimated incidence of 2.4%. Seven of these nine patients had Koos grade 4 tumors. Mean tumor diameter was 3.0 cm (range: 2.1–4.4 cm), and seven of nine tumors were subtotally resected. All nine patients were followed up clinically for ≥ 6 months. Of the six patients with a preoperative House–Brackmann grade of II, two improved to grade I, three were stable, and one patient worsened to grade III. Of the three patients with grade III or worse, all remained stable at last follow-up. Conclusions Preoperative facial nerve palsy is rare in patients with vestibular schwannoma; it tends to occur in patients with relatively large lesions. Detailed long-term outcomes of facial nerve function after microsurgical resection for these patients have not been reported previously. We followed nine patients and found that eight (89%) of the nine patients had either stable or improved facial nerve outcomes after treatment. Management strategies varied for these patients, including rates of subtotal versus gross-total resection and the use of stereotactic radiosurgery in patients with residual tumor. These results can be used to help counsel patients preoperatively on expected outcomes of facial nerve function after treatment.

Incidence and Risk Factors of Delayed Facial Palsy After Vestibular Schwannoma Resection

Neurosurgery ◽  
2015 ◽  
Vol 78 (2) ◽  
pp. 251-255 ◽  
Author(s):  
Lucas P. Carlstrom ◽  
William R. Copeland ◽  
Brian A. Neff ◽  
Marina L. Castner ◽  
Colin L.W. Driscoll ◽  
...  
Keyword(s):  
Risk Factors ◽  
Vestibular Schwannoma ◽  
Facial Palsy ◽  
Tumor Resection ◽  
Normal Function ◽  
Early Postoperative Period ◽  
Facial Nerve Function ◽  
Facial Weakness ◽  
Facial Function ◽  
Study Inclusion

ABSTRACT BACKGROUND: Preservation of facial nerve function following vestibular schwannoma surgery is a high priority. Even those patients with normal to near-normal function in the early postoperative period remain at risk for delayed facial palsy (DFP). OBJECTIVE: To evaluate the incidence and prognosis of DFP and to identify risk factors for its occurrence. METHODS: A retrospective cohort study of 489 patients who underwent vestibular schwannoma resection at our institution between 2000 and 2014. Delayed facial palsy was defined as deterioration in facial function of at least 2 House-Brackmann (HB) grades between postoperative days 5 to 30. Only patients with a HB grade of I to III by postoperative day 5 were eligible for study inclusion. RESULTS: One hundred twenty-one patients with HB grade IV to VI facial weakness at postoperative day 5 were excluded from analysis. Of the remaining 368, 60 (16%) patients developed DFP (mean 12 days postoperatively, range: 5-25 days). All patients recovered function to HB grade I to II by a mean of 33 days (range: 7-86 days). Patients that developed DFP had higher rates of gross total resections (83% vs 71%, P = .05) and retrosigmoid approaches (72% vs 52%, P &lt; .01). There was no difference in recovery time between patients who received treatment with steroids, steroids with antivirals, or no treatment at all (P = .530). CONCLUSION: Patients with a gross total tumor resection or undergoing a retrosigmoid approach may be at higher risk of DFP. The prognosis is favorable, with patients likely recovering to normal or near-normal facial function within 1 month of onset.

Pre-operative and per-operative factors conditioning long-term facial nerve function in vestibular schwannoma surgery through translabyrinthine approach

1998 ◽  
Vol 112 (5) ◽  
pp. 441-445 ◽  
Author(s):  
Olivier Deguine ◽  
André Maillard ◽  
Alain Bonafe ◽  
Hassan El Adouli ◽  
Michel Tremoulet ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Stage Iv ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Stimulation Threshold ◽  
Translabyrinthine Approach ◽  
Facial Function

AbstractFacial nerve function was evaluated in 103 patients, after vestibular schwannoma removal through the translabyrinthine approach. The mean follow-up was 43 months (minimum six months). Grade I facial function was achieved in 100 per cent of stage I schwannomata compared with 36 per cent of stage IV schwannomata. Grade I or II facial function was found in 78 per cent of homogeneous schwannomata, compared with 48 per cent of heterogeneous schwannomata. Facial function was preserved in 89 per cent of cases, if the angle between the internal auditory canal and the schwannoma was >66°, compared with 54 per cent if the angle was <66°. There was 82 per cent of normal facial function when the nerve appeared normal after tumour removal, compared with 18 per cent when the nerve was traumatized. When the ratio (stimulation threshold at the internal auditory canal/stimulation threshold at brainstem) was <2, postoperative facial function was preserved in 87 per cent of cases, compared with 13 per cent when the ratio was >2.

Facial nerve function after vestibular schwannoma surgery

2011 ◽  
Vol 115 (4) ◽  
pp. 820-826 ◽  
Author(s):  
Maurizio Falcioni ◽  
Paolo Fois ◽  
Abdelkader Taibah ◽  
Mario Sanna
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Tumor Size ◽  
Middle Cranial Fossa ◽  
Optimal Size ◽  
Tumor Diameter ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Tumor Removal ◽  
Total Tumor Removal

Object The object of this study was to evaluate long-term postoperative facial nerve (FN) function in patients undergoing vestibular schwannoma (VS) surgery. Methods The authors retrospectively reviewed the clinical course of patients affected by isolated VSs with normal preoperative FN function, with no previous surgical or radiotherapeutic treatment, and who underwent surgery between 1987 and 2007. Facial nerve function was clinically evaluated according to the House-Brackmann (HB) scale. The minimum postoperative follow-up was 12 months. Results Among the 1550 patients surgically treated at the authors' center, 1151 matched inclusion criteria for the present study. The FN was anatomically interrupted in 48 cases (4.2%), and 51 patients (4.4%) underwent subtotal tumor removal and were considered separately. Among the 1052 patients with anatomically preserved FNs and total tumor removal, 684 (65%) enjoyed postoperative HB Grade I or II and 309 (29.4%) enjoyed Grade III, with the remaining 59 cases (5.6%) suffering unsatisfactory results (HB Grades IV–VI). As expected, FN function results deteriorated in cases of larger tumors. Conclusions The main factor influencing postoperative FN function was tumor size. Although there was a progressive deterioration in FN function outcome in relation to tumor size, a cutoff point between satisfactory and unsatisfactory results could be identified at around 2 cm in maximum extrameatal tumor diameter, with the “optimal size” for surgery identified at < 1 cm. This finding emphasizes the importance of an early diagnosis and should be kept in mind when selecting the correct timing for VS removal. For small lesions, the results following a middle cranial fossa approach were significantly worse as compared with those following the translabyrinthine and retrosigmoidretrolabyrinthine approaches.

scholarly journals Long-term facial nerve clinical evaluation following vestibular schwannoma surgery

2008 ◽  
Vol 66 (2a) ◽  
pp. 194-198 ◽  
Author(s):  
Rafaela Julia Batista Veronezi ◽  
Yvens Barbosa Fernandes ◽  
Guilherme Borges ◽  
Ricardo Ramina
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Tumor Size ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Significant Difference ◽  
Long Term Follow Up ◽  
Facial Function

BACKGROUND: Facial function is important in accompaniment of patients operated on vestibular schwannoma (VS). OBJETIVE: To evaluate long term facial nerve function in patients undergoing VS resection and to correlate tumor size and facial function in a long-term follow-up. METHOD: Transversal study of 20 patients with VS operated by the retrosigmoid approach. House-Brackmann Scale was used preoperatively, immediately after surgery and in a long-term follow-up. Student t test was applied for statistic analysis. RESULTS: In the immediate postoperative evaluation, 65% of patients presented FP of different grades. Improvement of facial nerve function (at least of one grade) occurred in 53% in the long-term follow-up. There was statistically significant difference in facial nerve outcome in long-term follow-up when tumor size was considered (p<0.05). Conclusion: The majority of patients had improvement of FP in a long-term follow-up and tumor size was detected to be a factor associated with the postoperative prognostic.

Delayed facial palsy after resection of vestibular schwannoma

2002 ◽  
Vol 97 (1) ◽  
pp. 93-96 ◽  
Author(s):  
Gerald A. Grant ◽  
Robert R. Rostomily ◽  
D. Kyle Kim ◽  
Marc R. Mayberg ◽  
Donald Farrell ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Facial Palsy ◽  
Tumor Resection ◽  
Consecutive Series ◽  
Tumor Diameter ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Content Type ◽  
Fine Print

Object. In this study the authors investigate delayed facial palsy (DFP), which is an underreported phenomenon after surgery for vestibular schwannoma (VS). The authors identified 15 (4.8%) patients from a consecutive series of 314 who underwent surgery for VS between 1988 and 2000, and in whom DFP developed. Delayed facial palsy was defined as a deterioration of facial nerve function from House—Brackmann Grades 1 or 2 more than 3 days postoperatively. Methods. All patients underwent intraoperative neurophysiological monitoring of facial nerve function. The average latency of DFP was 10.9 days (range 4–30 days). In six patients (40%) minor deterioration (≤ two House—Brackmann grades) had occurred at a mean of 10.2 days postsurgery, whereas in nine patients (60%) moderate deterioration (≥ three House—Brackmann grades) had occurred at a mean of 11.8 days postoperatively. Five (33%) of 15 patients recovered to Grade 1 of 2 function within 6 weeks of DFP onset. Of the 15 patients with DFP, 14 had completed 1 year of follow up at the time of this study. Twelve (80%) of these 15 patients recovered to Grade 1 or 2 function within 3 months, and 13 (93%) of 14 patients recovered within 1 year. In all cases, stimulation of the seventh cranial nerve on completion of tumor resection revealed the nerve to be intact, both anatomically and functionally, to proximal and distal stimulation at 0.1 mA. A smaller tumor diameter correlated with greater recovery of facial nerve function. There was no correlation between the latency or severity of or recovery from DFP, and the patient's age or sex, the surgical approach, frequency of neurotonic seventh nerve discharges, anatomical relationship of the facial nerve to the tumor, patient's history of tobacco use, or cardiovascular disease. Conclusions. It appears that DFP is an uncommon consequence of surgery for VS. Although excellent recovery of facial nerve function to its original postoperative status nearly always occurs after DFP, the magnitude and time course of the disorder were not predictors for subsequent recovery of facial nerve function.

scholarly journals Endoscopic-assisted microsurgical resection of giant vestibular schwannoma in semi-sitting position

2021 ◽  
Vol 5 (2) ◽  
pp. V3
Author(s):  
Gang Song ◽  
Liyong Sun ◽  
Yuhai Bao ◽  
Jiantao Liang
Keyword(s):  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Residual Tumor ◽  
Nerve Function ◽  
Tumor Removal ◽  
Function Preservation ◽  
Microsurgical Resection ◽  
Dissection Technique ◽  
Total Tumor Removal ◽  
Facial Function

The main objectives of microsurgery for vestibular schwannoma are total tumor removal and preservation of facial and cochlear nerve function. For giant tumors, total tumor removal and facial nerve function preservation are challenging. The semisitting position has some advantages. In this video the authors show the removal of a giant vestibular schwannoma with the patient in a semisitting position. They demonstrate the advantages of the semisitting technique, such as the two-handed microsurgical dissection technique and a clear operative field. Finally, a small residual tumor in the internal auditory canal was removed by endoscopy. The patient’s facial function was House-Brackmann grade I at discharge. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2176

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