Rapidly growing cystic vestibular schwannoma with sudden onset facial palsy, ten years after subtotal excision

"Large and giant vestibular schwannomas: overall outcomes and the factors influencing facial nerve function"

(1) To study the overall outcomes of patients surgically treated for large/giant vestibular schwannomas (VSs) and (2) to identify and analyze preoperative and intraoperative prognostic factors influencing facial nerve (FN) outcome. A retrospective clinical study was conducted at a quaternary referral otology and skull-base center. A total of 389 cases were enrolled. The inclusion criteria were patients with tumor > 30 mm undergoing surgery with a minimum follow-up of 12 months. Neurofibromatosis-II, previous radiotherapy, revision surgeries, preoperative FN House-Brackmann (HB) grade > I, partial resections, incomplete records, or those lost to follow-up for a minimum period of 1 year were excluded. In addition, partial resections and cases where FN was sacrificed intraoperatively were also excluded and were analyzed separately. The mean duration of symptoms was 35.4 months, pronounced more in elderly (58.3 months) than in younger individuals (28.4 months). Mean tumor diameter was 36 mm and 52.7% was cystic. Total resection (TR), near total resection (NTR), and subtotal resections (STR) were achieved in 77.4%, 9.5%, and 13.2% of cases, respectively. Regrowth was observed only after STR (19.6%). Good (HB I-II), moderate (HB III), and poor (HB IV-VI) FN functions were observed in 36.8%, 51.7%, and 11.6% cases, respectively. Younger individuals underwent TR in 259 (86.9%) cases against 42 (46.2%) in elderly individuals. Non-total resections (NTR/STR) were performed in 49 (53.8%) cases in elderly as against 39(13.1%) in younger individuals. Good FN outcome was observed in 28 (57.1%) cases of non-total resections in elderly as against 13 (33.3%) cases in younger individuals. On multiple logistic regression analysis, size of the tumor, preoperatively prolonged duration of symptoms, profound deafness, and antero-superiorly located FN with respect to the tumor played a detrimental role in the final facial nerve outcome postoperatively. On the contrary, in large tumors (3-3.9 cm), presence of vertigo/disequilibrium had a relatively better impact on final FN outcome. Partial resections accounted for 41(7.8%) cases and FN was interrupted in 71(13.6%) cases in total. Factors detrimental to better FN outcome were giant VSs (> 4 cm), antero-superiorly located FN intratumorally, preoperatively prolonged duration of symptoms, and profound deafness. In large tumors (3-3.9 cm), presence of vertigo/disequilibrium had a better impact on FN outcome. Understandably, cases with TR in comparison with NTR/STR had worse FN outcomes. In comparison with younger patients, elderly patients underwent higher NTR/STR resulting in better FN outcomes. The above factors can be used as prognosticators for patient counseling and surgical decision making.

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.