Onco-Functional Balance in Large Vestibular Schwannomas Surgery: Is There a Sweet Spot between Extent of Resection and Quality of Life?

Introduction: Vestibular schwannomas (VS) are benign entities, but due to neurovascular relations they are among the most challenging tumors of the skull base. Possible management strategies are: observational wait-and-scan, irradiation, surgery, or a combination of them. The surgical dilemma concerns the balance between pursuing an extensive resection or leaving tumor remnants along eloquent structures: to date, there is still no unambiguous opinion. The main purpose of this retrospective study is to analyze surgical strategies and philosophies, oncological outcomes and complications of VSs surgery.

Methods: Our institution’s surgical database was retrospectively reviewed looking for patients operated for VS during the period 2012 to 2023. Baseline clinical and surgical data, operative records, oncological treatments, neuroimaging and long-term clinical data were obtained. Surgery was performed under general anesthesia assisted by IONM in all cases; resection was stopped when an easy dissection plane between tumor and neurovascular structures was undetectable, or an A-train on EMG recording was encountered. Data were analyzed by means of statistical analysis.

Results: A total of 220 patients (15–83 years) underwent surgery for VS. Mortality rate was 1.4%; morbidity rate (CDG > 1) was 18.15%. GTR was achieved in 103 patients (46.8%), near-total resection (NTR, i.e., residual tumor capsule thickness ≤ 5 mm along at most two among the IAC, the 7th-8th CN, or the brainstem) in 73 (33.2%), PR or STR in 44 (20%). Facial nerve functioning worsening occurred in 142 patients (64.5%), in 21.3% defined severe (drop ≥ 3 points in HB score). Good facial nerve function (HB I and II) was achieved in 46.5% of patients immediately postoperative and was associated with: smaller preoperative tumor diameters (p < 0.001), larger percentage of residual tumor and its superficial extension (“residual tumor spread”) (p < 0.001). At long-term FU, tumor dimension remains relevant (p = 0.019), whereas residual volume loses significance (t = 0.232, p = 0.817) with an overall improvement of 7thCN function registered in 74%. An immediate postoperative CN deficit (diplopia, trigeminal disturbances, lower cranial nerves impairment) is strictly related to VS diameter, especially the ventro-dorsal petrosal one (p < 0.001); and weakly associated with the EOR (p = 0.05). These remain significant for long-term persistency of CN deficits. Oncological control was defined by no necessity for further therapies (stable residual or no tumor recurrence): indication for adjuvant treatment is strongly related (t = 7.606, p < 0.001) to tumor diameters and EOR, with GTR and NTR having the same rate of disease control (p = 0.001), whereas other groups are at higher risk of tumor regrowth. Quality of life (PANQOL-It) resulted good overall with a total average value of 75.16: higher scores are associated with preoperative KPS (p < 0.001), absent brainstem edema (p = 0.002), and smaller tumor maximal diameter (p = 0.029); a pejorative longitudinal trend is detected after PR and STR with adjuvant treatment, but no difference with GTR and NTR was shown (p = 0.006).

Conclusion: QoL and oncological control are superimposable for GTR and NTR in VS surgery: we advocate for NTR when pushing resection further becomes riskier ([Tables 1] [2] [3]).

 

MissingLinkText

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
07 February 2025