Effectiveness of additional C2 decompression of the cervical spinal canal after cervical laminoplasty: a retrospective cohort study.

PURPOSE: This study aimed to assess the effects of additional C2 decompression of the cervical spinal canal on the postoperative outcomes after cervical laminoplasty in patients with cervical stenosis caused by ossification of the posterior longitudinal ligament (OPLL).

MATERIALS AND METHODS: This retrospective cohort study included patients with cervical stenosis due to OPLL and treated between April 2014 and December 2015. The patients who underwent C2-7 (additional C2 decompression) and C3-7 posterior decompression were compared using the Japanese Orthopedic Association (JOA) scores, visual analog scale (VAS) scores, axial symptom scores, and intervals between the posterior margin of the vertebral body and the K-line.

RESULTS: There were 36 and 24 patients in the additional C2 decompression and control groups, respectively. The JOA scores were higher in the additional C2 decompression group than the controls at 1 and 3 years ( p   <   0.05). Upper extremity motor function after the operation and at 1 and 3 years and lower extremity motor function after operation were improved in the additional C2 decompression group (all p   <   0.05 vs. controls). VAS scores were lower in the additional C2 decompression group than controls at 1 year ( p   <   0.05). Axial symptom scores in the additional C2 decompression group were decreased postoperatively but increased at 1 and 3 years ( p   <   0.05 vs. controls). Finally, the posterior shift of the K-line in the additional C2 decompression group was significant (from 0.98 to 1.68 cm, p   <   0.05).

CONCLUSIONS: Additional C2 decompression might improve the effectiveness of cervical laminoplasty in patients with cervical stenosis caused by OPLL.