title: Clinical outcomes, radiologic kinematics, and effects on sagittal balance of the 6 df LP-ESP lumbar disc prosthesis.
abstract: BACKGROUND
  Surgical treatment of degenerative disc disease remains a controversial subject. Lumbar fusion has been associated with a potential risk of segmental junctional disease and sagittal balance misalignment. Motion preservation devices have been developed as an alternative to fusion. The LP-ESP disc is a one-piece deformable device achieving 6 df, including shock absorption and elastic return. This is the first clinical report on its use.
  
  
  OBJECTIVE
  To assess clinical outcomes and radiologic kinematics in the first 2 years after implantation.
  
  
  METHODS
  Prospective cohort of patients with LP-ESP total disc replacement (TDR) at the lumbar spine.
  
  
  METHODS
  Forty-six consecutive patients.
  
  
  METHODS
  Clinical outcomes were the visual analog scale (VAS) for pain, the Oswestry disability index (ODI), and the GHQ28 (General Health Questionnaire) psychological score. Radiologic data were the range of motion (ROM), sagittal balance parameters, and mean center of rotation (MCR).
  
  
  METHODS
  Patients had single-level TDR at L4-L5 or L5-S1. Outcomes were prospectively recorded for 2 years (before and at 3, 6, 12, and 24 months after surgery). The SpineView software was used for computed analysis of the radiographic data. Paired t tests were used for statistical comparisons.
  
  
  RESULTS
  No intraoperative complication occurred. All clinical scores improved significantly at 24 months: the back pain VAS scores by a mean of 4.1 points and the ODI by 33 points. The average ROM of the instrumented level was 5.4°±4.8° at 2 years and more than 2° for 76% of prostheses. The MCR was in a physiological area in 73% of cases. The sagittal balance (pelvic tilt, sacral slope, and segmental lordosis) did not change significantly at any point of the follow-up.
  
  
  CONCLUSIONS
  Results from the 2-year follow-up indicate that LP-ESP prosthesis recreates lumbar spine function similar to that of the healthy disc in terms of ROM, quality of movement, effect on sagittal balance, and absence of modification in the kinematics of the upper adjacent level.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Pitié-Salpétrière Hospital, Assistance Publique-Hopitaux de Paris, 47-83 boulevard de l'hôpital, 75013 Paris, France; Biomechanics Lab, Arts et Métiers Paristech, 151 boulevard de l'hôpital, 75013 Paris, France.
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Lazennec
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Pitié-Salpétrière Hospital, Assistance Publique-Hopitaux de Paris, 47-83 boulevard de l'hôpital, 75013 Paris, France; Biomechanics Lab, Arts et Métiers Paristech, 151 boulevard de l'hôpital, 75013 Paris, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Even
authors.affiliation: Biomechanics Lab, Arts et Métiers Paristech, 151 boulevard de l'hôpital, 75013 Paris, France.
authors.forename: Wafa
authors.initials: W
authors.lastname: Skalli
authors.affiliation: Clinique du Pré, 13 Ave. René Laennec, 72018 Le Mans, France.
authors.forename: Jean-Patrick
authors.initials: JP
authors.lastname: Rakover
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Pitié-Salpétrière Hospital, Assistance Publique-Hopitaux de Paris, 47-83 boulevard de l'hôpital, 75013 Paris, France.
authors.forename: Adrien
authors.initials: A
authors.lastname: Brusson
authors.affiliation: Biomechanics Lab, Arts et Métiers Paristech, 151 boulevard de l'hôpital, 75013 Paris, France; Department of Orthopaedic and Trauma Surgery, Avicenne Hospital, Assistance Publique-Hopitaux de Paris, 125 rue de Stalingrad, 93009 Bobigny, France. Electronic address: marc-antoine.rousseau@avc.aphp.fr.
authors.forename: Marc-Antoine
authors.initials: MA
authors.lastname: Rousseau
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D008161:Lumbosacral Region / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D004856:Postural Balance; D011859:Radiography; D016059:Range of Motion, Articular; D059145:Total Disc Replacement / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D016896:Treatment Outcome
keywords: Back pain; Degenerative disc disease; Lumbar spine; Mean center of rotation; Sagittal balance; Total disc replacement