title: Multiple Osseous Loose Bodies Associated with Lumbar Isthmic Spondylolisthesis.
abstract: BACKGROUND
  Multiple osseous loose bodies in the lumbar spine have never been reported. We describe a rare surgical case of multiple osseous loose bodies associated with lumbar isthmic spondylolisthesis.
  
  
  METHODS
  A 74-year-old man who experienced left foot numbness and bilateral gluteal pain was diagnosed with lumbar spondylolisthesis 7 years previously and managed conservatively. He reported recurrence of the left foot numbness 6 months previously, at which time aggressive (rather than conservative) therapy became a consideration. Radiographs of the lumbar spine revealed L5 isthmic spondylolisthesis with dynamic instability at L5/S1. Magnetic resonance imaging of the lumbar spine revealed multiple mass lesions dorsally located in the lumbar canal. Computed tomography myelography demonstrated multiple osseous materials near the isthmic portion at the L5 level where compression of the dural sac by the lesions induced lumbar canal stenosis. The patient underwent posterior decompression surgery that enabled total removal of the osseous lesions. Intraoperative findings revealed osseous lesions located in the fibrocartilage material and no connection of the lytic portion at the L5 level or ligamentum flavum. Postoperative course of the patient was uneventful as his neurological symptoms improved.
  
  
  CONCLUSIONS
  We described the first instance of multiple loose bodies in the spinal canal with lumbar canal stenosis. It is presumed that long standing minor trauma due to dynamic instability with a trend of hyperossification induced secondary synovial osteochondromatosis forming multiple loose bodies.
authors.affiliation: Department of Spinal Disorders Center, Fujieda Heisei Memorial Hospital, Fujieda, Shizuoka, Japan; Department of Neurosurgery, Nara Medical University School of Medicine, Kashihara, Nara, Japan. Electronic address: takeshim@naramed-u.ac.jp.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takeshima
authors.affiliation: Department of Spinal Disorders Center, Fujieda Heisei Memorial Hospital, Fujieda, Shizuoka, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Hanakita
authors.affiliation: Department of Spinal Disorders Center, Fujieda Heisei Memorial Hospital, Fujieda, Shizuoka, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Department of Neurosurgery, Nara Medical University School of Medicine, Kashihara, Nara, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakase
mesh_terms: D000368:Aged; D019299:Decompression, Surgical; D006801:Humans; D007594:Joint Loose Bodies / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D009192:Myelography; D011859:Radiography; D013115:Spinal Canal / Q000000981:diagnostic imaging / Q000601:surgery; D013130:Spinal Stenosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D013168:Spondylolisthesis / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed
keywords: Dynamic instability; Isthmic spondylolisthesis; Loose body; Lumbar canal stenosis; Multiple lesions; Synovial chondromatosis