title: A less-invasive cervical laminoplasty for spondylotic myelopathy that preserves the semispinalis cervicis muscles and nuchal ligament.
abstract: OBJECTIVE
  Modified cervical laminoplasty techniques have been developed to reduce postoperative axial neck pain and preserve function in patients with cervical spondylotic myelopathy (CSM). However, the previous studies demonstrating satisfactory surgical outcomes had a retrospective design. Here, the authors aimed to prospectively evaluate the 2-year outcomes of a modified cervical laminoplasty technique for CSM that preserves the paravertebral muscles.
  
  
  METHODS
  Outcomes were analyzed for 40 patients (22 men and 18 women; mean age, 66.6 years; age range 44-92 years) with CSM who underwent C4-6 laminoplasty with C-3 and C-7 partial laminectomies or C-3 total and C-7 partial laminectomies and received hydroxyapatite spacers. Neurological, pain severity, and spinal radiographic evaluations were performed preoperatively and at 3, 6, 12, 18, and 24 months postoperatively. Plain radiography and MRI of the cervical spine were performed to evaluate the range of motion (ROM), sagittal alignment, and cross-sectional areas of the deep extensor muscles. The extent of bone-spacer bonding and bony union at the gutter was assessed by CT.
  
  
  RESULTS
  The mean preoperative Japanese Orthopaedic Association CSM score was 10.2, but it increased to 14.4 by 24 months after surgery. Eleven patients had axial neck pain preoperatively, but only 3 reported mild pain at 24 months, and in all 3 cases the pain was mild. The mean angle of lordosis was 11.7° preoperatively and 12.0° 2 years postoperatively. Although the ROM at the C2-7 levels was significantly reduced 3 months postoperatively, an increasing trend was observed up to 12 months, and 86% of the preoperative ROM was achieved by 2 years postoperatively. The mean paravertebral muscle cross-sectional areas were 833 ± 215 mm(2) preoperatively and 763 ± 197 mm(2) 24 months postoperatively, but the difference was not statistically significant. The rates of bone-spacer bonding and bony union at the gutter were low during the early stages but increased to 90% and 93%, respectively, by 2 years after surgery.
  
  
  CONCLUSIONS
  The modified laminoplasty technique used in this study ensured very good neurological status and ROM after 2 years and was associated with low incidences of axial neck pain and serious complications. This simple and easy operative method could benefit future laminoplasty protocols.
authors.affiliation: Department of Orthopedic Surgery, Kansai Medical University, Hirakata City, Osaka.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Umeda
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Sasai
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Kushida
authors.forename: Ei
authors.initials: E
authors.lastname: Wakabayashi
authors.forename: Tokun
authors.initials: T
authors.lastname: Maruyama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ikeura
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Iida
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008023:Ligaments, Articular / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000601:surgery; D010146:Pain / Q000601:surgery; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D012720:Severity of Illness Index; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D055009:Spondylosis / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome