title: Lumbar total disc replacement by less invasive lateral approach: a report of results from two centers in the US IDE clinical trial of the XL TDR® device.
abstract: OBJECTIVE
  To evaluate the clinical and radiographic outcomes following total disc arthroplasty using the XL TDR(®) Lumbar Disc in the treatment of patients with symptomatic degenerative disc disease at one level between L1-2 and L4-5.
  
  
  METHODS
  Data were compiled from two centers participating in a prospective, multi-center Food and Drug Administration-approved investigational device exemption clinical trial enrolling patients with single-level lumbar degenerative disc disease unresponsive to non-operative treatment. Longitudinal outcomes were evaluated through 3-year follow-up and included patient-reported pain, function, and general health, as well as radiographic measures such as maintenance of disc height and range of motion.
  
  
  RESULTS
  The two-center cohort included 64 treated patients, 42 % female, averaging 45.3 years of age (range 26-67). The majority of procedures were performed at the L4-5 level (75 %), uncomplicated, with minimal blood loss (88 % 0-50 cc), and in an outpatient setting (93.8 %). Postoperative events included 10 patients (15.6 %) with new hip flexion weakness, 7 (10.9 %) with new lower extremity weakness, and 10 (15.6 %) with new lower extremity sensory deficits, all resolved by 3 months in all but two patients whose deficits were prolonged but eventually resolved. Average disc height increased postoperatively from 7.2 to 12.1 mm (69 %), and was 10.7 mm (49 % increase from preoperative) at 3 years. Flexion/extension range of motion averaged 5.9° (SD 4.8°) at 3 years, and was not statistically different from preoperative (p = 0.471). Heterotopic ossification interfering with segmental motion was noted in 3 patients (10.3 %) at 3 years, none ankylosed (Grade IV). Postoperative improvement in patient-reported outcomes was significant (p < 0.01 for all measures) and maintained through 3-year follow-up. Satisfaction with results was reported by 85 % (51/60) of patients at 2 years and 93 % (28/30) at 3 years. There were no revisions through 3 years postoperative.
  
  
  CONCLUSIONS
  The results following XL TDR show good clinical and radiographic outcomes out to 3 years postoperative, with clinically significant improvements in pain, function, and general health, few complications, and high patient satisfaction.
authors: Northwest Orthopaedic Specialists, 212 East Central, Suite 140, Spokane, WA, 99208, USA, tohmeh@comcast.net.
authors: Antoine G
authors: AG
authors: Tohmeh
authors: William D
authors: WD
authors: Smith
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000453:epidemiology; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D011183:Postoperative Complications; D011446:Prospective Studies; D016059:Range of Motion, Articular; D059145:Total Disc Replacement / Q000295:instrumentation* / Q000379:methods*; D014481:United States / Q000453:epidemiology