Myriad Ways to Skin the Nerve: Preliminary Experience with a Side-Cutting Mechanical Aspirator for Vestibular Schwannoma Resection

Introduction: Microsurgical dissection of vestibular schwannomas (VS) is a highly effective management strategy for appropriately selected patients. However, developing the surgical plane between tumor capsule and the cisternal/meatal segments of the facial nerve is technically challenging, often time-inefficient, and risky. Unfortunately, there have been few contemporary advances in the realm of surgical instruments and devices to improve safety, efficiency, and/or efficacy during this portion of VS surgery. In this investigation, we sought to describe a novel application of a non-rotary, side-cutting, mechanical aspirator into our multidisciplinary intraoperative VS resection workflow. The objectives of this investigation were to (1) demonstrate non-inferiority; (2) describe safe and practical applications for use of this device; 3) delineate optimal situations where this device may replace existing instrumentation.

Methods: Cohort study of first 16 sequential patients undergoing VS resection with our dedicated neurosurgery-neurotology team after adoption of the side-cutting mechanical aspirator. A comparison to 16 sequential VS resection cases preceding the novel device integration with descriptive analysis was done. Parameters studied included postoperative facial nerve function, operating time, and extent-of-resection, all adjusted for preoperative tumor volume. A 3D operative video will be provided for demonstration of various techniques for the use of this device.

Results: Of 16 sequential VS patients treated during the side-cutting mechanical aspirator integration period (06/01/21 to 09/15/2021), favorable facial nerve function (House-Brackmann grade I–II) was maintained in 14 (87.5%) in the immediate postoperative period. All of these patients are expected to return to their baseline function. Gross total resection (GTR) was achieved in 10 (62.5%) and near-total resection (NTR) in 6 (37.5%) patients. Median operating time was 330 minutes, versus 410 minutes in the control group. The device was implemented on 3 previously radiated tumors. Greatest time savings were perceived to be in the final 15% of tumor dissection, although this difference could not be calculated from the preliminary data. In the comparison group treated with traditional instrumentation, there was not a significant difference in resection rates. Ultimate facial nerve outcomes are not expected to differ significantly from those resected with the side-cutting device. After adjusting for tumor volumes, there were no differences in tumor presentation between both groups (p = 0.1937). Surgeon feedback indicated that the side-cutting mechanical aspirator was most useful during terminal debulking of medium-to-large VS, particularly in post-radiated tumors and cases with highly attenuated facial nerves.

Conclusion: From our preliminary experience, the side-cutting mechanical aspirator for VS resection appears non-inferior to standard-of-care contemporary instrumentation and devices. Subjective surgeon feedback indicated that it may provide additional benefit during terminal VS debulking, where the tumor capsule and a nerve plane are not distinguishable, offering a more efficient tool during preparation for final facial-nerve tumor interface dissection. Further study is required to characterize clinical impact; however, the initial data reported here are encouraging, and support the formal assessment of the side-cutting mechanical aspirators in a controlled trial setting ([Figs. 1]–[3]).

Fig. 1 Shaving off a previously radiated tumor with the side-cutting mechanical aspirator.

Fig. 2 Myriad handpiece.

Fig. 3 Myriad tip zoom view.

Publikationsverlauf

Artikel online veröffentlicht:
15. Februar 2022