LAUSR

OBJECTIVE To modify the conventional methods of grooving and direction during the single-door cervical laminoplasty (SDCL) in the subaxial cervical spine. METHODS The distance between the left and the right lamina-lateral mass junction at the upper, middle, and lower levels of each segment (DLL-U, DLL-M, DLL-L), angle between the posterior edge of the vertebral body and the lamina (AVL) and thickness of lamina (TL) were measured in the transverse plane. The parameters of preoperative computed tomography scans of 200 patients who had undergone SDCL were measured. The patients were divided into male and female groups and developmental canal stenosis (DCS) and non-DCS (NDCS) groups. RESULTS DLL-M gradually increased from the cranial to the caudal except for C7, and DLL-L > DLL-M > DLL-U in each vertebra. AVL increased from C3 to C7, TL decreased from C3 to C5 and increased from C5 to C7, with both parameters showing no significant differences between the left and right sides. AVL of the DCS group was less than that of the NDCS group (P < 0.01). CONCLUSIONS In the SDCL, the ideal surgical trough should be several discontinuous lines sloping from top to bottom, rather than a straight line. The abduction angle during drilling should gradually increase from C3 to C7 in the SDCL averaging 40 degrees. This method mentioned above improves the efficiency of the operation with less blood loss as an extended cut into the lateral mass is avoided.