title: Retrospective study on effectiveness of activ L total disc replacement: clinical and radiographical results of 1- to 3-year follow-up.
abstract: METHODS
  Retrospective case series study.
  
  
  OBJECTIVE
  To assess the effectiveness of activ L total disc replacement (TDR) on degenerative disc diseases with the clinical and radiographical results.
  
  
  BACKGROUND
  There are few reports on activ L TDR. This is the first one from China.
  
  
  METHODS
  From March 2009 to March 2012, 32 patients with degenerative disc diseases underwent mono- or bisegmental lumbar TDR. Mean age was 45.1 years (32-58 yr). Clinical outcomes were measured by Oswestry Disability Index and Visual analogue scale pre- and postoperatively (1, 2, and 3 yr). Radiographical parameters as range of motion and intervertebral disc height of the index- and adjacent segments were also measured. Prosthesis subsidence and heterotopic ossification were observed during the follow-up period. Work status was also tracked.
  
  
  RESULTS
  Thirty patients were available for a mean follow-up of 28.8 months and had complete radiographical data. At the final follow-up, the success rate was 86.7%. Visual analogue scale score for low back pain and leg pain, and Oswestry Disability Index scores significantly improved after surgery. Average intervertebral disc heights of patients with more than 3 years' follow-up at the index segment and upper and lower adjacent segments were 12.87 mm, 12.61 mm, and 11.62 mm, respectively, showing no significant difference compared with preoperative scores. The range of motion of the index and upper adjacent segments showed a significant increase for patients with more than 3 years' follow-up. Changes of range of motion at lower adjacent segment were not significant. We observed tears of the iliac vein in 2 patients, prosthesis subsidence in 3 patients, and heterotopic ossification in 1 patient. At the final follow-up, 18 patients went back to their original work, 8 patients changed jobs, and 4 patients stopped working.
  
  
  CONCLUSIONS
  The 1- to 3-year follow-up of this cohort of patients showed satisfactory clinical outcomes. The long-term results of activ L TDR need more investigation.
  
  
  METHODS
  2.
authors.affiliation: From the Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.
authors.forename: Shibao
authors.initials: S
authors.lastname: Lu
authors.forename: Chao
authors.initials: C
authors.lastname: Kong
authors.forename: Yong
authors.initials: Y
authors.lastname: Hai
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Zang
authors.forename: Nan
authors.initials: N
authors.lastname: Kang
authors.forename: Xianglong
authors.initials: X
authors.lastname: Meng
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging* / Q000601:surgery; D055959:Intervertebral Disc Degeneration / Q000000981:diagnostic imaging / Q000601:surgery*; D007595:Joint Prosthesis; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D011859:Radiography; D012189:Retrospective Studies; D059145:Total Disc Replacement