Postlaminoplasty cervical range of motion: early results

Object. The authors studied cervical range of motion (ROM) before and after cervical lamidoplasty to determine factors associated with cervical ROM in patients with cervical myelopathy. Methods. Between July 2003 and August 2005, 20 patients underwent a modified Hirabayashi-type unilateral open-door laminoplasty to treat multilevel cervical spondylosis or ossification of the posterior longitudinal ligament (OPLL). Clinically, the authors assessed Japanese Orthopaedic Association (JOA) score, duration of symptoms, disease entity, and the age and sex of patients to ascertain the relation of these factors to ROM before and after cervical laminoplasty. Intraoperative findings such as ligament detachment from the C-2 spinous process and cervicothoracic junction involvement were noted. Radiological and imaging findings such as the length of the lesion, cervical axial canal area, anteroposterior (AP) diameter of the cervical canal, angle of the opened lamina after surgery, cervical sagittal angles, cervical curvature index (CCI), and signal change of the cord on magnetic resonance imaging were evaluated. The mean follow-up period was 19.45 months (range 13-38 months). The preoperative average ROM in 18 patients (after excluding two patients with trauma) was 36.73 +/- 15.73 degrees postoperatively it was 25.24 +/- 16.06 degrees. Thus, ROM decreased by 9.64 +/- 10.09 degrees (31.80%) after surgery (p = 0.002), reflecting the mean in the same 18 patients. Preoperative ROM was related to the age of patients, CCI, preoperative JOA score, and AP diameter of the cervical canal. In cases of OPLL the ROM was lower than that in cases of spondylosis. Postoperative cervical ROM was related to preoperative ROM, postoperative AP diameter of the cervical canal, laminar angle, patient age, and follow-up duration. None of the studied parameters, however, correlated with a decreased cervical ROM. Conclusions. Cervical ROM was reduced after cervical laminoplasty. Postlaminoplasty cervical ROM had a positive correlation with extended motion; however, gradually it became reduced. In this study, no correlative factor was associated with a reduction in cervical ROM. Further study is also needed.