Preservation of the Lesser Occipital Nerve Prevents Occipital Sensory Disturbance After Microvascular Decompression: Long-Term Results

Abstract

In microvascular decompression (MVD) surgery for hemifacial spasm (HFS), preservation of the lesser occipital nerve (LON) will prevent occipital sensory disturbance, a frequent complication of MVD, but the long-term outcome is unknown. This study was designed to evaluate the long-term efficacy of LON preservation. This retrospective study included 257 patients with HFS who underwent suboccipital craniotomy with MVD. Among them, 175 were followed-up for more than 2 years. Occipital sensation was examined at 1, 12, and 24 months after MVD. The patients were classified into 3 groups based on their operative findings: LON preservation (group A; n= 112), LON not identified (group B; n= 117), and LON excision (group C; n= 28). The degree of sensory disturbance was evaluated using a visual analog scale (VAS) ranging from 1 (no sensation) to 10 (intact). The VAS score at 1 month was significantly better in group B (7.9 ± 0.2) than in groups A and C (7.3 ± 0.2 and 6.8 ± 0.4, respectively). At 24 months, the VAS scores were significantly higher in groups A and B (9.7 ± 0.1 and 9.7 ± 0.1) than in group C (8.8 ± 0.4), and occipital scalp sensation remained intact (VAS scores 9 and 10) in 91.9%, 92.9%, and 62.5% of the patients in groups A, B and C, respectively. Our long follow-up study has demonstrated that preservation of the LON during MVD prevents sensory disturbance of the occipital scalp. Efforts to preserve the LON appear to be worthwhile when the suboccipital approach is chosen.