Romanian Neurosurgery (Nov 2024)
NEW TECHNOLOGIES AVAILABLE FOR MICRONEUROSURGICAL REMOVAL OF ACOUSTIC NEUROMAS
Abstract
Introduction The aim of this study was to analyze the results of microsurgery removal of acoustic neuromas (AN) using new technologies: flexible hand-held laser fiber, Sonopet Ultrasound Aspirator, Facial Nerve “detector” monopolar stimulation (for localize position and course of facial nerve), BAER’s with level specific (LS) CE-Chirp stimulus for hearing preservation, endoscope for IAC final check, and injectable bone substitute for closure. We report a retrospective nonrandomized clinical study on 300 cases consecutively operated on. Material and Methods From July, 2010 to December, 2023, 350 consecutive patients suffering from AN have been operated on with microneurosurgical technique by key-hole retrosigmoid approach. In majority of cases tumor resection was performed with the aid of a handheld flexible laser fiber. In the same period, Sonopet Ultrasound aspirator was used for tumor debulking and/or opening of the internal auditory meatus and canal. From May 2015, hearing preservation by means LS CE-Chirp BAER was attempted in patients with preoperative socially useful hearing (AAO-HNS class A and B). In addition, we check the removal of tumor inside the internal auditory canal (IAC) by using the flexible and/or rigid endoscope, for completing tumor removal near the fundus. Results Overall time from incision to skin suture changed in relation to size of tumor (from 165 to 575 minutes) and was not affected by the use of hand-held laser. Facial nerve function was clinically assessed with the House-Brackmann (HB) scale preoperatively, in the early postoperative period (after 1 week), and at 6-month follow-up. In 3 cases a preoperative facial nerve palsy was observed (HB III and HB IV, respectively). In the remaining cases, 6 months after surgery facial nerve preservation rate (HB I) was 92%, Hearing preservation rate (AAO-HNS A and B, pre- and postoperatively) was 52% in eligible cases. Total and “nearly total” removal of tumor was possible in about 80% of cases. Dura closure was performed with underlaying autologous pericranium. Injectable bone substitute in the gaps after bone flap repositioning minimized postoperative CSF leakage and improved the aesthetic result. Conclusions The use of new technologies (handheld flexible laser fibers, Sonopet Ultrasound Aspirator, fluoreceine, Nimbus facial nerve continuous monitoring, LS CE-Chirp BAER, endoscope for IAC final check) in AN microsurgery seems to be safe and efficacious and facilitates tumor resection, especially in ‘‘difficult’’ conditions (e.g., large size, highly vascularized, or hard tumors). The good functional outcome following conventional microsurgery seems to be further improved and the extent of tumor removal could be increased with the proper use of the new technologies available in the neurosurgical armamentarium.
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