Comparison of long-term clinical and radiographic outcomes between alternative-level and all-level fixation unilateral open-door laminoplasty

Abstract

BACKGROUND CONTEXTTitanium mini-plate has been used in unilateral open-door laminoplasty to maintain the open angle of laminae. Previously, both all-level fixation (C3–C7) and alternative-level (C3, C5, C7) unilateral open-door laminoplasty have been proven to have satisfactory clinical outcomes. However, whether they could achieve similar long-term clinical and radiographic efficacy is still questionable. PURPOSETo compare the long-term clinical and radiological outcomes between alternative-level and all-level fixation unilateral open-door laminoplasty with a mini-plate fixation system. STUDY DESIGN/SETTINGRetrospective comparative study. PATIENT SAMPLENinety-one patients who underwent unilateral open-door laminoplasty. OUTCOME MEASURESClinical results including Japanese Orthopedic Association score, Visual Analogue Score, Neck Dysfunction Index score. Radiographic results including cervical curvature index, cervical range of motion, and the spinal canal expansive parameters, including anteroposterior diameter, Pavlov's ratio, and open angle. METHODSBetween April 2007 and June 2011, 91 patients with minimum 7-year postoperative follow-up were included. Thirty-eight underwent alternative-level fixation (group A) and 53 underwent all-level fixation (group B). Demographic data, including age, gender, operative time, blood loss, and cost, were collected and compared between the two groups. Clinical and radiographic data were obtained preoperatively, at 3 and 6 months and 1 and 3 years postoperatively, as well as at final follow-up. The difference between the two groups and between different time points within one group was compared. RESULTSBoth groups obtained satisfactory clinical outcomes till the final follow-up. No statistic difference was found in Japanese Orthopedic Association, Visual Analogue Score, and Neck Dysfunction Index between the two groups throughout the whole follow-up. Both groups maintained APD and Pavlov's ratio well till follow-up. However, statistic difference was found in the open angle between two groups at final follow-up (34.17±2.75° vs. 36.19±1.80°, p<.05). When we subdivided the cervical segments in group A, we found the mini-plate segments showed maintenance in open angle but a 4.52° decrease in suture segments. The mean cost in group B (17,669.82±1,157.65 $) was significantly higher than in group A (11,452.19±871.07 $; p<.05). CONCLUSIONSDespite a difference in the maintenance of open angle, both fixation methods achieved satisfactory clinical outcomes. We believe alternative-level fixation is also a safe, effective, and economical fixation method.