Cervical malalignment after laminoplasty: relationship to deep extensor musculature of the cervical spine and neurological outcome

Object. The goal of this study was to investigate the relationship between preservation of the insertion of the deep extensor musculature of the cervical spine at C-2 and postoperative cervical alignment, especially differences between cases involving male and female patients, as well as the relationship between the loss of cervical lordosis and neurological outcome after laminoplasty. Methods. The authors reviewed the records of 50 patients who underwent laminoplasty to elevate the C-3 lamina with repair of the deep extensor musculature (Group A) and 31 patients who underwent laminoplasty by C-3 dome laminotomy or laminectomy (Group B). They compared the degree of cervical lordosis after laminoplasty with preoperative measurements. Neurological function at last follow-up was also compared with preoperative assessments. Results. In Group A, the mean values for pre- and postoperative cervical lordosis were 14.5 and 10.9 degrees, respectively (p > 0.18). In female patients, however, the pre- and postoperative means were 14.4 and 3.7 degrees, respectively (p < 0.004). In Group B, the overall means for pre- and postoperative cervical lordosis were 17.3 and 19.1 degrees, respectively (p > 0.48); the corresponding means for female patients were 15.0 and 14.1 degrees (p > 0.83). The mean percentages of neurological recovery were 54.1% in Group A and 54.8% in Group B. Conclusions. Preservation of the insertion of the deep extensor musculature to the C-2 spinous process prevented significant changes in cervical alignment after laminoplasty, even among female patients. Neurological recovery was not affected by the loss of cervical lordosis.