Isolated Marginal Mandibular Nerve Injury Due to Prone Positioning During Cervical Spine Surgery: A Case Report.

Injury to the marginal mandibular nerve (MMN) as an isolated complication of posterior cervical spine surgery performed in the prone position is exceedingly rare, with only a handful of documented instances in indexed surgical literature. We present the case of a 60-year-old gentleman who developed unilateral lower facial deviation immediately following a seven-hour posterior cervical decompression and multilevel instrumented stabilization procedure. The deficit was confined entirely to the distribution of the MMN, with no involvement of other facial nerve branches or adjacent peripheral nerves. The clinical findings were most consistent with positional MMN neuropraxia, and the patient was managed conservatively with physiotherapy and ENT guidance, with early evidence of recovery before discharge. This report aims to draw the attention of spine surgeons to a complication that is probably underrecognized and underreported and to underline the anatomical and technical considerations that can reduce its occurrence.