Degenerative Cervical Myelopathy in a Patient With Klippel-Feil Syndrome Accompanied by Congenital Anomalies of the Pedicle and Lateral Mass: A Case Report

Klippel-Feil syndrome is a rare congenital cervical fusion anomaly that may lead to degenerative changes and neurological symptoms later in life.Degenerative cervical myelopathy is progressive, and surgical treatment is recommended in moderate and severe cases.A 53-year-old man presented with progressive weakness, spastic gait, and neuropathic complaints.Neurological examination revealed spastic quadriparesis with hyperreflexia, ankle clonus, and bilateral Hoffmann sign positivity.The preoperative modified Japanese Orthopaedic Association score was 11, and the Nurick grade was three.Imaging demonstrated congenital C2-C3 fusion consistent with Klippel-Feil syndrome type II, multilevel cervical canal stenosis, and hypoplasia of the right C5 pedicle and lateral mass.C3-C4-C5 laminectomy was performed for decompression, and lateral mass screw and rod instrumentation was applied over C3-C6.Because the right C5 lateral mass was hypoplastic, no screw was placed at that site; the right-sided construct spanned C3, C4, and C6, and C5 was anchored on the left only.At 18 months the modified Japanese Orthopaedic Association score had improved to 16 and the Nurick grade to one, with no implant-related complications.Degenerative cervical myelopathy arising on a background of Klippel-Feil syndrome may require individualized surgical planning, because coexisting congenital anomalies can determine which fixation points are usable.Careful preoperative radiological assessment and posterior decompression with stabilization can provide satisfactory clinical outcomes.