INTRODUCTION: Lumbar fusion is associated with a potential risk of sagittal balance misalignment and adjacent disc disease. As an alternate to fusion, motion preservation devices have been developed. The purpose of this study was to determine the effects on kinematics, sagittal balance and clinical outcomes of the LPESP® total disc arthroplasty. The LP‐ESP® disc is a one‐piece deformable achieving 6 degrees of freedom, including shock absorption and elastic return.
METHODS: Total disc replacement at a single level was performed in 43 consecutive patients aged 43.8 in average. The ODI, SF36 and GHQ28 clinical scores were prospectively noted pre‐op, at 3 months, 6 months, and one‐year follow‐up. The spineview software was used for measuring the sagittal parameters in standing position and the kinematics in flexion extension, including range of motion and mean center of rotation at the level of the articificial disc and at the cranial adjacent level.
RESULTS: The range of motion (ROM) was 5 degrees ± 4.8 degrees. 68% of prosthesis had more than 2 degrees of ROM. The mean centre of rotation was in a classically defined usual area in 87.5% of cases. The pelvic tilt, sacral tilt and segmental lordosis were significantly improved with respectively 16.7±7.8, 36.5±10.6 and 19.4±6.7 degrees preoperatively and 12.9±6.5, 40.1±9.8 and 27.8±7.8 degrees at follow‐up. ROM, MCR, disc height of the adjacent upper level did not change during the followup. No intra‐operative complication occurred. All clinical scores were significantly improved: 4.8 points for the back pain visual analogue scale, 33.8 points for the Oswestry disability index (ODI), 3.8 points for the SF36, and 17 points for the GHQ28.
DISCUSSION: At one‐ follow‐up, it appears that the LP‐ESP® prosthesis is clinically efficient and recreates the properties of a healthy disc in term of quality of local and adjacent intervertebral movement, and regarding the sagittal balance of the lumbar spine.