title: Extraordinary positional cervical spinal cord compression in extension position as a rare cause of postoperative progressive myelopathy after cervical posterior laminoplasty detected using the extension/flexion positional CT myelography: one case after laminectomy following failure of a single-door laminoplasty/one case after double-door laminoplasty without interlaminar spacers.
abstract: Posterior cervical laminectomies and laminoplasties are common treatments for cervical spondylotic myelopathy. However, recent studies demonstrated that positional spinal cord compression occurred after cervical laminectomies and caused postoperative progressive myelopathy. Although there were no such reports after laminoplasties, we report two cases in which symptomatic extraordinary positional spinal cord compression occurred after laminoplasties in this paper.
  
  
  
  This study included two patients who showed progressive myelopathy: one case after a laminectomy following failure of a single-door laminoplasty and one case after a double-door laminoplasty without interlaminar spacers.
  
  
  
  The MRIs showed mild cord compression in the neutral position in both cases. However, the patients could not extend their necks, because it triggered severe neck pain and numbness. Therefore, the positional CT myelography (CTM) was taken in the flexion and extension positions, and it showed severe spinal cord compression only in the extension position. Posterior instrumented fusions were performed for both patients, which improved their symptoms.
  
  
  
  This paper demonstrates that postoperative positional spinal cord compression during neck extension caused a progressive myelopathy even after laminoplasty. When myelopathy symptoms worsen after laminoplasties, we recommend positional CTM/MRI evaluation, even though there is no apparent cord compression in the neutral MRI.
authors.affiliation: Department of Orthopaedic Surgery, Hiroshima City Asa Citizens Hospital, Kabe-minami 2-1-1, Asakita-ku, Hiroshima, 731-0293, Japan. ys.fujiwara@nifty.com.
authors.forename: Yasushi
authors.identifier: 0000-0003-4124-3802
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Department of Orthopaedic Surgery, Hiroshima City Asa Citizens Hospital, Kabe-minami 2-1-1, Asakita-ku, Hiroshima, 731-0293, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Manabe
authors.affiliation: Department of Orthopaedic Surgery, Hiroshima City Asa Citizens Hospital, Kabe-minami 2-1-1, Asakita-ku, Hiroshima, 731-0293, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Harada
authors.affiliation: Department of Orthopaedic Surgery, Hiroshima City Asa Citizens Hospital, Kabe-minami 2-1-1, Asakita-ku, Hiroshima, 731-0293, Japan.
authors.forename: Bunichiro
authors.initials: B
authors.lastname: Izumi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Adachi
mesh_terms: D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D006987:Hypesthesia / Q000209:etiology; D007796:Laminectomy; D065406:Laminoplasty; D008279:Magnetic Resonance Imaging; D008297:Male; D009192:Myelography; D019547:Neck Pain / Q000209:etiology; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000601:surgery; D011782:Quadriplegia / Q000209:etiology / Q000601:surgery; D016059:Range of Motion, Articular; D013117:Spinal Cord Compression / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D013123:Spinal Fusion; D055009:Spondylosis / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: Laminectomy; Laminoplasty; Positional CT myelography; Positional spinal cord compression; Progressive myelopathy