A mid-term clinical analysis of the treatment of ossification of the posterior longitudinal ligament with C1,2 single-door laminoplasty

Objective To analyze the mid-term clinical efficacy of extended to C1, 2 posterior single-door laminoplasty for the treatment of ossification of the posterior longitudinal ligament combined the upper cervical spine. Methods From February 2013 to December 2015, 32 patients with cervical OPLL who were extended to C1, 2 posterior open-door laminoplasty were enrolled in our hospital (complete follow-up of 25 patients). There were 19 males and 6 females, aged 48-76 years (mean 60.1±7.0 years). Cervical spinal cord function was assessed using the Japanese Orthopaedic Association (JOA) spinal cord function score, and the rate of improvement in neurological function was calculated. The quality of life of patients was assessed using the neck disability index (NDI). Axial symptoms were assessed and indexed using the visual analog scale (VAS). The C0-2 angle of the cervical spine was measured by X-ray preoperative and at the last follow-up. The cervical curvature was evaluated by the C2-7 angle, and the cervical vertebra activity was observed by the dynamic X-ray of the cervical spine. Results 25 patients were followed up for a period of 26-64 months (mean 35.9±8.1 months). At the last follow-up, the JOA score was 14.32±3.24, the NDI score was 7.61±1.23, and the VAS score was 1.42±0.78. The differences between the three scores were statistically significant compared with the preoperative scores. The neurological improvement rate at the last follow-up was 79.61%±13.23%. The preoperative C0-2 angle was 26.04°±6.28°, and the last follow-up was 24.92°±5.51°; the C2-7 angle was 19.55°±9.42° before surgery, and the C2-7 angle at last follow-up was 17.97°±8.80°. The C2-7 angle at last follow-up was slightly reduced compared with that preoperative, but the difference was not statistically significant. The preoperative cervical vertebra ROM was 35.31°±12.24°, and at the last follow-up it was 32.23°±9.65°. The ROM of cervical vertebrae at the last follow-up was slightly lower than that before surgery, but the difference was not statistically significant. Among them, the reduction of the ROM of overflexion was greater than that of the over-extension, which was the main reason for the decrease of ROM. The OPLL bone mass continued to grow at the last follow-up of 11 patients. Conclusion The extended to C1, 2 posterior single-door laminoplasty for the treatment of ossification of the posterior longitudinal ligament combined the upper cervical spine can achieve adequate spinal cord decompression, satisfactory neurological improvement, and improve the postoperative cervical curvature and activity. There was no obvious change in the curvature and activity of the cervical spine, and the axial symptoms did not increase significantly, and the clinical efficacy was positive. Key words: Ossification of posterior longitudinal ligament; Cervical vertebrae; Treatment outcome