title: Congenital absence of lumbosacral articular facet joint associated with conjoined nerve root: a case report.
abstract: We report a rare case of congenital absence of the L5-S1 facet joint, which was associated with a conjoined nerve root. Combination of these two anomalies has been quite rarely reported in the literature. A 39-year-old man presented with acute low back pain and right leg radiating pain. Muscle weakness and sensory disturbance of the right leg were also apparent in the region innervated by L5 and S1 nerve roots. Preoperative multidetector three-dimensional computed tomography (3D-CT) showed complete absence of the right S1 superior articular process. Magnetic resonance (MR) images showed lumbar disc herniation at right L5-S1 level that migrated cranially. Intraoperative findings revealed that the right L5 nerve root and S1 nerve root were conjoined, and the conjoined nerve root was compressed by L5-S1 disc herniation, which led to impairment of the conjoined nerve root by a single-level lumbar disc herniation. After removal of the disc herniation, his right leg pain immediately subsided, however muscle weakness and sensory disturbance persisted. Surgeons should be aware of this nerve root anomaly when examining a patient who shows an unusual clinical presentation and/or congenital osseous anomaly.
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Yoshioka
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sakai
authors.forename: Natsuo
authors.initials: N
authors.lastname: Yasui
mesh_terms: D000015:Abnormalities, Multiple / Q000175:diagnosis / Q000601:surgery; D000328:Adult; D019299:Decompression, Surgical / Q000379:methods; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007405:Intervertebral Disc Displacement / Q000175:diagnosis / Q000601:surgery*; D017116:Low Back Pain / Q000175:diagnosis / Q000209:etiology; D008159:Lumbar Vertebrae / Q000503:physiopathology* / Q000601:surgery; D008160:Lumbosacral Plexus / Q000002:abnormalities*; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D035583:Rare Diseases; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D021801:Zygapophyseal Joint / Q000002:abnormalities* / Q000601:surgery