title: Postoperative changes at the lower end of cervical laminoplasty: for preservation of the C7 spinous process in laminoplasty.
abstract: BACKGROUND
  C3-C7 laminoplasty has been the standard treatment for cervical myelopathy, although several recent reports described C3-C6 laminoplasty for preserving the muscles inserting in C7 and reducing postoperative axial symptoms. However, postoperative changes at C6/C7 of the lower end of C3-C6 laminoplasty, especially regarding a possibility of postoperative spinal canal narrowing have not been measured. The purpose of this study was to clarify postoperative changes at the lower end of laminoplasty.
  
  
  METHODS
  Pre and postoperative spinal dura diameter at the lower end of conventional C3-C7 laminoplasty using MRI, and the related factors for spinal dura diameter and the causes of postoperative dura narrowing were investigated.
  
  
  RESULTS
  At the last follow-up after C3-C7 laminoplasty, dura diameter at C7/T1 was significantly wider after operation than before operation, and postoperative narrowing of dura diameter, which was found in 20% of patients, was a maximum amount of one millimeter. No pre and postoperative factor significantly correlated with dura diameter at C7/T1. The causes of postoperative narrowing at the lower end of laminoplasty were disc protrusion and/or posterior scar, or segmental angulation of the spinal cord.
  
  
  CONCLUSIONS
  In conclusion, the presence of preoperative subarachnoid space over one millimeter at C6/C7 may be able to be one of the radiological indications for C3-C6 laminoplasty.
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University School of Medicine, Hirosaki, Aomori, Japan. naritake03@ybb.ne.jp
authors.forename: Kazunari
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Toru
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Shuichi
authors.initials: S
authors.lastname: Aburakawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ono
authors.forename: Takuya
authors.initials: T
authors.lastname: Numasawa
authors.forename: Gentaro
authors.initials: G
authors.lastname: Kumagai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Toh
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000473:pathology*; D005260:Female; D006801:Humans; D007796:Laminectomy; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000473:pathology* / Q000601:surgery*; D011184:Postoperative Period; D013128:Spinal Osteophytosis / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome