Lamina angle and spinal canal expansion in open-door and double-door laminoplasty

Abstract

Background Open-door and double-door laminoplasty (ODL and DDL, respectively) have been widely used for the treatment of multilevel cervical stenotic conditions. However, the comparison of post-operative spinal canal expansion between the two techniques relative to the pre-operative lamina angle has not been investigated. Objective To verify the accuracy of the simulation model and to predict the spinal canal expansion after laminoplasty (ODL and DDL) relative to the pre-operative lamina angle. Methods The parameters including length, angle and area of 64 patients who had undergone C3-C6 laminoplasty (43 patients with ODL and 21 patients with DDL) were measured on computed tomography scans by picture archiving and communication system software. The GeoGebra software was used to simulate laminoplasty. The accuracy of the simulation was evaluated by comparing the clinical data with the simulation data. ODL and DDL were simulated to determine the amount of canal enlargement at various pre-operative lamina angles. Results A comparison of the data obtained by clinical investigation and simulation showed no significant difference (p > 0.05)andaveryhighdegreeofcorrelation(p < 0.001). The increase in the spinal canal area (SCA) of ODL cases was significantly greater than that of DDL cases when the pre-operative lamina angle was 32° and less

however, the increase in the SCA of DDL cases was significantly greater than that of ODL cases when the pre-operative lamina angle was 33° and more. Conclusion When the pre-operative lamina angle was 32° and less, ODL is advantageous in terms of an increase in SCA.