Kinematic characteristics of lumbar spinous processes during axial rotation in patients with lumbar degenerative disc disease lateral lumbar interbody fusion and intervention

BACKGROUND Data about minimally invasive surgery for the treatment of patients with degenerative disc disease (DDD) has been reported. However, no quantitative knowledge about the biomechanical characteristics of the spinous processes in patients with DDD after operation was reported in the literature. METHODS Fourteen adult patients with DDD at the L3-4 level were recruited and scanned using computed tomography (CT) to construct three-dimensional (3D) anatomical vertebral models of L2-5. These patients were asked to maintain four positions to acquire 6DOF data about the area of the spine being investigated (L2-5). Fluoroscopy was used to capture spinal motion. 6DOF data from the fluoroscopic images of the four positions was compared to evaluate the kinematics before operation and 6 months after direct lateral interbody fixation (DLIF). RESULTS Altered kinematics were found mainly in rotation. For the images captured while patients were in the supine position, no significant differences were detected in different functional positions before and after operation. At other positions, the most kinematic involved level was the L3-4 level, which was followed by the L4-5 level. The range of flexion-extension motion at all levels decreased after operation (by an average of 1° to 7°) while different trends were found in left-right bending/rotation. Overall, after surgical treatment, functional activities were partially restored. CONCLUSIONS Overall the lumbar spinous processes (LSP) at each level responded differently, regarding rotation, before and after DLIF. This data provides new insights for the evaluation of function before and after surgical treatment in patients with LSP disease.