Clinical and radiologic outcomes of bone grafted and non-bone grafted double-door laminoplasty, the modified Kirita-Miyazaki method, for treatment of cervical spondylotic myelopathy: Five-year follow-up.

PURPOSE: To clarify whether there is any difference in mid-term clinical and radiologic outcomes between bone-grafted laminoplasty (BG LAMP) and non-bone-grafted laminoplasty (non-BG LAMP) when used to treat cervical spondylotic myelopathy.

BACKGROUND: Conventional BG LAMP includes bone grafting at the lamina hinge site to prevent closure of the lamina postoperatively, but it often results in segmental fusion and sometimes causes loss of cervical mobility and lordotic alignment. Non-BG LAMP can now be performed to address this problem and preserve mobility postoperatively. However, there have been no studies comparing BG LAMP and non-BG LAMP to date.

METHODS: Forty-one patients who underwent BG LAMP (n = 24) or non-BG LAMP (n = 17) and had 5 years of follow-up were enrolled in the study. Neurological status was assessed preoperatively and postoperatively using the Japanese Orthopedic Association (JOA) scoring system. The Numeric Rating Scale (NRS) was used to assess neck pain after surgery at the final visit. Radiographic parameters were evaluated at 1, 3, and 5 years after surgery. Postoperative segmental fusion was defined as the level at which the segmental flexion-extension range of motion was <1°.

RESULTS: There was no significant difference in JOA score or recovery rate between the groups. NRS score was significantly lower in the BG group, indicating less neck pain (P < .01). The lordotic angle and range of motion at C2-C7 were significantly decreased in the BG group (P < .05). The segmental fusion was evident from 1 year postoperatively in both groups, but the fusion rate was significantly higher in the BG group (P < .05).

CONCLUSIONS: Neurologic outcomes were similar between the two groups, whereas axial symptom was lower in the BG group than in the non-BG group.

LEVEL OF EVIDENCE: Ⅳ.