Indication for a skull base approach in microvascular decompression for hemifacial spasm

Area of Science:

• Neurosurgery
• Skull Base Surgery
• Vascular Neurology

Background:

• Microvascular decompression (MVD) for hemifacial spasm (HFS) requires precise visualization of the root exit zone (REZ) and offending arteries.
• A narrow operative field via the retrosigmoid approach can limit decompression feasibility.
• Lateral extension of the craniectomy may be necessary for safe MVD procedures.

Purpose of the Study:

• To evaluate the benefits of a skull base approach in MVD for HFS.
• To compare the skull base approach with the conventional retrosigmoid approach for MVD in HFS patients.
• To identify indications and assess outcomes of the skull base approach for MVD.

Main Methods:

• Retrospective analysis of 28 patients who underwent MVD for HFS using a skull base approach, out of 335 consecutive cases.
• Measurement of neurovascular compression (NVC) site, flocculus size, and sigmoid sinus location on imaging.
• Comparison of skull base approach indications and outcomes against the conventional retrosigmoid approach.

Main Results:

• The skull base approach (extended retrosigmoid or retrolabyrinthine presigmoid) was utilized in 28 patients.
• Imaging measurements correlated with the indication for the skull base approach, differing significantly from the conventional retrosigmoid approach.
• The skull base approach proved beneficial for cases with medially located NVC, large flocculus, or in repeat MVD procedures, showing favorable long-term results.

Conclusions:

• Preoperative assessment for lateral craniectomy expansion is vital for safe and effective MVD.
• The skull base approach provides a viable alternative for complex MVD cases in HFS.
• Favorable long-term outcomes support the use of the skull base approach in selected HFS patients.