Study design: Evaluation of lumbar total disc arthroplasty (TDA) in military patients.
Objective: To evaluate the clinical and radiographic outcomes of US military personnel who have undergone TDA for degenerative disc disease and to assess the retention versus discharge rate after undergoing this procedure.
Summary of background data: TDA was developed as an alternative to arthrodesis for the surgical management of degenerative disc disease with the goal of preserving motion and reducing adjacent segment disease. However, the indications and optimal candidates for this procedure are uncertain. Military members must maintain a certain level of physical fitness and be capable of meeting the demands of hazardous environments. This study reviews results of TDA performed on active duty military members.
Methods: The surgery schedules from 2005 to 2008 were reviewed to identify military members who underwent single-level or 2-level TDA for degenerative disc disease after failing at least 6 months of conservative management. All patients had a minimum of 2-year follow-up. Preoperative and postoperative clinical assessments were completed using the Oswestry Disability Index (ODI) questionnaire and the numeric rating scale (NRS). Radiographs were evaluated to determine range of motion, height, and disc position at the operated levels. The retention rate of the patients in the military was also recorded. Statistical analysis of the data was carried out with significance assumed at the P < 0.05 level.
Results: Thirty-eight patients, implanted with a total of 56 discs, met the criteria for retrospective analysis. Twenty patients had single-level and 18 had 2-level TDA. Mean age was 35 (23 to 56 y) years. Mean follow-up was 28 months. The overall mean preoperative ODI and NRS of 53.6 and 7.3, significantly improved postoperatively to 27.7 and 3.3, respectively (P < 0.001). There was no difference in the postoperative ODI (P = 0.19) or NRS (P = 0.18) when comparing single-level and 2-level TDA. Clinical success was achieved in 79% of patients. Mean range of motion was 6.5 degrees and the mean disc height increased by 69%. Sixty-eight percent of patients returned to full active duty.
Conclusions: This study showed clinical success approaching 80% in military patients who underwent lumbar TDA. Furthermore, close to 70% were able to return to their positions within the military. TDA, while more closely reapproximating the normal biomechanics of the spine, may provide patients with an improved alternative to spinal arthrodesis for degenerative disc disease.