title: Effect of multilevel open-door laminoplasty and laminectomy on flexibility of the cervical spine: an experimental investigation.
abstract: METHODS
  A biomechanical comparison of 2 commonly used posterior surgical procedures for spinal cord decompression in the cervical spine: laminoplasty (open door) and laminectomy.
  
  
  OBJECTIVE
  To delineate differences in cervical motion after laminoplasty (2-level and multilevel) and laminectomy.
  
  
  BACKGROUND
  Cervical spondylotic myelopathy is a common spinal cord disorder in persons aged 55 years or older. Laminectomy and laminoplasty are the 2 common posterior-based techniques used for decompression of spinal cord. There is lack of adequate literature data on the intersegmental rotations at the operated and adjacent levels.
  
  
  METHODS
  Five human cadaveric specimens were tested sequentially as follows: (1) intact, (2) laminoplasty at C5-C6, (3) laminoplasty at C3-C6, and (4) laminectomy at C3-C6, each subjected to 2 N·m moments in flexion/extension, right/left lateral bending, and right/left axial rotation. For laminoplasty, the laminae of the involved vertebrae were stabilized with standard 10-mm plates and screws. The total and segmental motions of the specimens were measured before and after the surgical procedures. Statistical analysis was performed using repeated measures analysis of variance, with P < 0.05 as the level of significance.
  
  
  RESULTS
  Two-level laminoplasty led to minimal decrease (<7% in the 3 loading modes) in C2-T1 motion. Multilevel laminoplasty resulted in a minimal increase during lateral bending (4%) and axial rotation (6%). During flexion/extension, both C4-C5 and C2-C3 showed a decrease of 20% (P > 0.05) and 17% (P > 0.05) after 2-level and multilevel laminoplasty, respectively. Laminectomy resulted in a statistically significant (P < 0.05) increase in the C2-T1 range of motion compared with the intact condition during the 3 loading modes (21% in flexion/extension, 8% in lateral bending, and 15% in axial rotation).
  
  
  CONCLUSIONS
  Both 2-level and multilevel laminoplasty preserved the C2-T1 range of motion. Laminectomy resulted in a significant increase in C2-T1 motion due to the loss of the posterior structures.
authors.affiliation: Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA.
authors.forename: Swathi
authors.initials: S
authors.lastname: Kode
authors.forename: Anup A
authors.initials: AA
authors.lastname: Gandhi
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Fredericks
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Grosland
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Smucker
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D016059:Range of Motion, Articular; D012399:Rotation; D013117:Spinal Cord Compression / Q000601:surgery