Abstract

Purpose: Double-door laminoplasty (DDL) at the cervical spine (Kurokawa’s method) has a feature of central-splitting of the spinous processes and laminae with preserving their lengths. This procedure is technically demanding, and even now there remain some issues to be mentioned. The purpose of this study was to present the recent surgical methods and the results of DDL focusing on the changes of sagittal alignment of the cervical spine.
Methods: The sagittal alignment was examined using C2-C7 angle on X-ray films in 37 patients (33 males and 4 females, the age from 34 to 87 years old with 64.1 in average) followed up more than 1 year.
Results: Preoperatively, 33 patients had lordotic alignment with an average of 14.0 degrees. Postoperatively, the alignment changed toward less lordotic or kyphotic of about 10 degrees in 67% of patients. In 3 patients among 4 with preoperative kyphosis, the change toward more kyphotic was also about 10 degrees.
Conclusions: There are three essential procedures in DDL: First, to decompress the cervical spinal cord by central splitting of the spinous processes and laminae while preserving their lengths, resulting in a symmetrical widening of the spinal canal space. Second, to maintain the widened space stably by fixing with spacers of hydroxyapatite whose configuration is almost the same as that of the widened space. Third, to suture the semispinalis muscles to the ipsilateral inferior oblique occipital muscles before closure to restore their strength to the extent possible. After DDL, the sagittal alignment of the cervical spine can be expected to be well maintained postoperatively.