A clinical Study of C2 dome-like expansive laminoplasty and C2 expansive open-door laminoplastyinupper cervical ossifi-cation of the posterior longitudinal ligament

Objective To explore the clinical effects of C2 dome-like expansive laminoplasty and C2 expansive open-door laminoplasty in upper cervical(involve or above C2 segment) ossification of the posterior longitudinal ligament. Methods All of 39 patients (22 males and 17 females) withcervical ossification of the posterior longitudinal ligament up to C2 which causedcompression symptoms were operated with posterior cervical surgery in ourhospital from January 2013 to June 2017.The average age was 55.74+7.91 years old, ranging from 39 to 71 years. Among these patients, 21 patients underwent C2 dome-like expansive laminoplasty and 18 underwent C2 expansive open-door laminoplasty, the patients in both groups underwent the C3-C7 expansive open-door laminoplasty. The preoperative and postoperative Neck Disability Index (NDI), Japanese Orthopedic Association (JOA) score, the xisual analog scale(VAS) and the space available for the spinal cord (SAC) of C2 segment in X-ray were measured and statistically analyzed. Results All patients were followed up, the follow-up time was from 15 to 63 months (mean 42.3±17.7 months). There was no significant difference in the general condition, NDI, JOA score and JOA score improvement rate between preoperative and postoperative follow-up in 2 groups. There were significant differences in the NDI, JOA, VAS and SAC between preoperative and postoperative follow-up in 2 groups. The VAS score in C2 dome-like expan-sive laminoplasty group 1.52±1.2 was significantly lower than that in C2 expansive open-door laminoplasty group 2.06±0.87(t=-2.23, P<0.05), while the SAC in C2 expansive open-door laminoplasty group 14.11±1.023 was significantly higher than that in C2 dome-like expansive laminoplasty group 11.86±1.014(t=-6.89, P<0.05). No failure of internal fixation or recurrent compres-sion was found during follow-up. Conclusion For patients with ossification of posterior longitudinal ligament up to C2 or higher level, both C2 dome-like expansive laminoplasty and C2 expansive open-door laminoplasty can achieve good results. The SAC in C2 expansive open-door laminoplastygroup was superior to that in C2 dome-like expansive laminoplasty group, while the postoperative pain was more obvious. There was no significant difference in postoperative neurological recovery between the two groups. Using C2 dome-like expansive laminoplasty could reduce postoperative axial pain than the C2 expansive open-door laminoplasty surgery. For patients withossified tissue in the spinal canal, which occupies more than 50% of the sagittal diameter of the spinal canal, or with developmental spinal stenosis, C2 expansive open-door laminoplasty may berecommend to get more adequate decompression. Key words: Cervical vertebrae; Ossification of posterior longitudinal ligament; Axis; Decompression, surgical