Study design: A prospective study.
Objective: To identify the time-dependent change in range of motion (ROM) after cervical laminoplasty.
Summary of background data: Although numerous studies have reported on the loss of flexion/extension ROM associated with laminoplasty, few have reported on the time course of this loss of motion.
Methods: Twenty-three patients who received unilateral open-door laminoplasties, including miniplate fixation over 2 levels, were serially evaluated at regular set intervals after surgery. The mean follow-up period was 26.78 months (range: 24-41 months). Twelve patients had OPLL and 11 patients had cervical spondylotic myelopathy. Enrolled patients were divided into 2 groups (ossification of posterior longitudinal ligament [OPLL] and cervical spondylotic myelopathy) to compare the ROM between the OPLL and the spondylosis patients. We evaluated the time-dependent neck ROM changes by taking neutral, flexion, and extension radiographs before surgery and at 1, 3, 6, 9, 12, 18, and 24 months after surgery. Postoperative neck and arm pain was evaluated using a numerical rating scale.
Results: The preoperative, and 1-, 3-, 6-, 9-, 12-, 18-, and 24-month postoperative ROM figures were 37.8 degrees +/- 14.6 degrees, 34.1 degrees +/- 12.9 degrees, 35.0 degrees +/- 12.3 degrees, 30.3 degrees +/- 13.0 degrees, 28.6 degrees +/- 15.1 degrees, 27.3 degrees +/- 12.4 degrees, 26.1 degrees +/- 14.8 degrees, and 25.9 degrees +/- 13.2 degrees, respectively, and at the most recent follow-up, ROM was 25.8 +/- 15.2 degrees. Thus, the mean ROM decreased by 10.1 degrees +/- 9.5 degrees (31.66%) after surgery (P = 0.002). In OPLL group, we observed a more limited cervical ROM than in cervical spondylotic myelopathy group (35.3% vs. 29.2%). However, the rate of ROM reduction slowed with time in both groups (P = 0.000). Postoperative axial pain did not correlate with the degree of serial cervical ROM.
Conclusion: The results suggest that the loss of cervical ROM is time-dependent and plateaus by 18 months after surgery, with no further decreases thereafter.