Alternate levels versus all levels mini-plate fixation in C3-6 cervical laminoplasty: a retrospective comparative study

The purpose of this study is to compare radiological and clinical outcomes between alternate levels (C4 and C6) and all levels mini-plate fixation in C3-6 unilateral open-door laminoplasty.

Ninety-six patients who underwent C3-6 unilateral open-door laminoplasty with alternate levels mini-plate fixation (54 patients in group A) or all levels mini-plate fixation (42 patients in group B) between September 2014 and September 2019 were reviewed in this study. Radiologic and clinical outcomes were assessed. Clinical results included Visual Analogue Scale (VAS) of axial neck pain and Japanese Orthopedic Association (JOA) score. Radiographic results included cervical range of motion (ROM), cervical curvature index (CCI), and the spinal canal expansive parameters including open angle, anteroposterior diameter (APD), and Pavlov`s ratio.

There was no significant difference in VAS, JOA score, ROM, and CCI between two groups. There was no significant difference in canal expansion postoperatively between two groups. However, open angle, APD, and Pavlov`s ratio in group A decreased significantly during the follow-up. In group B, APD, Pavlov`s ratio, and open angle were maintained until the final follow-up. There was no hardware failure or lamina reclosure occurred in both groups during the follow-up. The mean cost of group B was higher than that of group A.

Despite the differences in the maintenance of canal expansion, alternate levels mini-plate fixation can achieve similar clinical outcomes as all levels mini-plate fixation in C3-6 unilateral open-door laminoplasty. As evidenced in this study, we believe C3-6 laminoplasty with alternate levels (C4 and C6) mini-plate fixation is an economical, effective, and safe treatment method.