Lumbar Total Disc Replacement by the Lateral Approach-Up to 10 Years Follow-Up

OBJECTIVE: This study aimed to analyze radiologic and clinical results with a minimum 5 years follow-up (FUP) of lateral lumbar total disc replacement for the treatment of symptomatic lumbar degenerative disc disease. METHODS: We performed a prospective, single-center, clinical, and radiologic study. Patients were treated with lumbar total disc replacement (extreme lateral total disc replacement) by a lateral transpsoas approach. From 2005 to 2012, 60 patients were enrolled (31 male, 29 female; total, 66 levels; average age, 42.8 years [standard deviation (SD), 9.7 years, range, 22-64 years]; mean body mass index, 26.0 [SD, 3.4]). Clinical end points included visual analog scale and Oswestry Disability Index questionnaires, complications, and reoperation. Radiographic end points included heterotopic ossification (McAfee classification), adjacent level disease, and prosthesis migration or subluxation. RESULTS: The mean surgical duration was 122 minutes (SD, 45 minutes) with mean 58 mL (SD, 21 mL) of estimated blood loss. No intraoperative complication occurred. The exceptions were 1 patient with postanesthesia apnea and 2 patients with quadriceps motor deficit (resolved within 4 months with physiotherapy). Of 60 patients, 9 were missed to FUP and 51 (85%) were enrolled in the study, with mean FUP of 92 months (range, 60-122 months). In total, 5 levels (9%; 5 of 55) required to be fused. Both removal of the prostheses and interbody fusion were performed by the lateral transpsoas approach. One patient experienced CrCo allergy (at 2 months); 4 experienced persistent pain from different causes (at 7, 9, 24, and 88 months). Five patients (10%) presented with progression at adjacent levels and 2 (4%) required surgery. One patient required sacroiliac fusion at 63 months. There were no complications during the retrieval surgeries. One partial disc migration occurred but the patient refused retrieval. There was no bone bridging in 9% of the discs (grade 0 heterotopic ossification): grade I, 22%; grade II, 31%; grade III, 20%; grade IV (fusion), 18%. Most heterotopic ossification cases (93%) occurred in the lateral aspect of the disc space, and mostly at the contralateral side of the surgical approach. Patient-reported outcomes significantly improved (P < 0.01) at the last FUP. Visual analog scale back pain score was preoperatively 8.5, early postoperatively 2.5, and at last FUP 3.1. Oswestry Disability Index was preoperatively 55%, early postoperatively 31%, and at last FUP 21%. CONCLUSIONS: This study presents mid-term to long-term results of extreme lateral total disc replacement artificial disc for the treatment of lumbar degenerative disease, with fast mobilization, sustained pain relief, and improved physical function. Despite the low rate of ALDis, some discs evolved to ankyloses and others were retrieved. Lumbar artificial disc replacement by the lateral approach seems to be a safe and effective treatment.