Optimizing surgical technique in microvascular decompression for hemifacial spasm - Results from a surgical series with contemporary use of neuronavigation and intraoperative neuromonitoring.

Background: Microvascular decompression (MVD) through a retrosigmoid approach is considered the treatment of choice in cases of hemifacial spasm (HFS) due to neurovascular conflict (NVC). Despite the widespread of neuronavigation and intraoperative neuromonitoring (IONM) techniques in neurosurgery, their contemporary application in MVD for HFS has been only anecdotally reported.

Methods: Here, we report the results of MVD performed with a combination of neuronavigation and IONM, including lateral spread response (LSR) in 20 HFS patients. HFS clinical outcome and different surgical-related factors, such as craniotomy size, surgical duration, mastoid air cell (MAC) opening, postoperative cerebral spinal fluid (CSF) leakage, sinus injury, and other complications occurrence, and the length of hospitalization (LOS) were studied.

Results: Postoperatively, residual spasm persisted only in two patients, but at the latest follow-up (FU) (mean: 12.5 ± 8.98 months), all patients had resolution of symptoms. The mean surgical duration was 103.35 ± 19.36 min, and the mean LOS was 2.21 ± 1.12 days. Craniotomy resulted in 4.21 ± 1.21 cm² in size. Opening of MAC happened in two cases, whereas no cases of CSF leak were reported as well as no other complications postoperatively and during FU.

Conclusion: MVD for HFS is an elective procedure, and for this reason, surgery should integrate all technologies to ensure safety and efficacy. The disappearance of LSR is a crucial factor for identifying the vessel responsible for NVC and for achieving long-term resolution of HFS symptoms. Simultaneously, the benefits of using neuronavigation, including the ability to customize the craniotomy, contribute to reduce the possibility of complications.