title: Instability of treated vertebrae after balloon kyphoplasty causing paraparesis in osteoporotic vertebral compression fracture: a report of two cases.
abstract: OBJECTIVE
  To describe two unique cases of osteoporotic vertebral compression fracture (OVCF) treated with balloon kyphoplasty (BKP) that were complicated by spinal instability and resultant lower extremity paraparesis.
  
  
  METHODS
  Kyphoplasty was performed in two patients with OVCF that had persistent back pain despite a course of conservative care. Immediately following BKP, both patients had a marked improvement in back pain. However, they developed progressive bilateral lower extremity weakness. Lateral spine flexion-extension radiographs demonstrated instability, and polymethyl methacrylate did not adhere to the endplate of the treated vertebrae.
  
  
  RESULTS
  Both the patients underwent a hybrid fixation without a decompression. Postoperatively, both of them demonstrated gradual improvement in their neurological exam.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first report describing the development of spinal instability with resultant delayed paraplegia following BKP. This case report demonstrates another cause of neurological decline following BKP, in the absence of cement leakage.
authors: Department of Orthopaedic Surgery, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan. tooba@yamanashi.ac.jp
authors: Tetsuro
authors: T
authors: Ohba
authors: Shigeto
authors: S
authors: Ebata
authors: Devin
authors: D
authors: Clinton
authors: Kenske
authors: K
authors: Koyama
authors: Hirotaka
authors: H
authors: Haro
mesh_terms: D000368:Aged; D001843:Bone Cements; D050815:Fractures, Compression / Q000601:surgery*; D006801:Humans; D058498:Kyphoplasty / Q000009:adverse effects*; D008297:Male; D010024:Osteoporosis / Q000601:surgery*; D058866:Osteoporotic Fractures / Q000601:surgery*; D020335:Paraparesis / Q000209:etiology*; D016103:Spinal Fractures / Q000601:surgery
chemical_list: D001843:Bone Cements