Preliminary Report of Fully Endoscopic Microvascular Decompression.

Objective: Microscopic microvascular decompression (MVD) has been considered to be a useful treatment modality for medically refractory hemifacial spasm (HFS) and trigeminal neuralgia. But, the advent of the endoscopic era has presented new possibilities to MVD surgery. While the microscope remains a valuable tool, the endoscope offers several advantages with comparable clinical outcomes. Thus, fully endoscopic MVD (E-MVD) could be a reasonable alternative to microscopic MVD. This paper explores the safety and efficacy of the fully E-MVD technique.

Methods: A single-center retrospective study was conducted in 25 patients diagnosed with HFS between September 2019 and July 2023. All surgeries were performed by a single neurosurgeon using the fully E-MVD technique without any assistance of a microscope. The study reviewed intraoperative brainstem auditory evoked potentials and disappearance of the lateral spread response. Outcomes were assessed based on the patients' clinical status immediately after surgery and at their last follow-up. Complications, including facial palsy, hearing loss, ataxia, dysphagia, palsy of other cranial nerves, and cerebrospinal fluid leakage, were also examined.

Results: The most common offending artery was the anterior inferior cerebellar artery (AICA) in 15 cases (60.0%), followed by the posterior inferior cerebellar artery in eight cases (32.0%), vertebral artery (VA) in one case (4.0%), tandem lesions involving the AICA and VA in one case (4.0%). Ten patients (40.0%) had pre-operative facial palsy on the ipsilateral side, and eight patients (32.0%) experienced delayed facial palsy on the ipsilateral side, from which they fully recovered by the last follow-up. The median operation time was 105 minutes. All patients were symptom free immediately after surgery and at the last follow-up. One patient experienced a permanent complication, such as high-frequency hearing loss, from which he partially recovered over time.

Conclusion: Fully E-MVD demonstrated similar clinical outcomes to microscopic MVD. It offered a similar complication rate, shorter operation time, and a panoramic view with a smaller craniectomy size. Although there is a learning curve associated with fully E-MVD, it presents a viable alternative in the endoscopic era.