title: Sagittal alignment after single cervical disc arthroplasty.
abstract: METHODS
  Prospective study.
  
  
  OBJECTIVE
  To analyze the sagittal balance after single-level cervical disc replacement (CDR) and range of motion (ROM). To define clinical and radiologic parameters those have a significant correlation with segmental and overall cervical curvature after CDR.
  
  
  BACKGROUND
  Clinical outcomes and ROM after CDR with Mobi-C (LDR, Troyes, France) prosthesis have been documented in few studies. No earlier report of this prosthesis has studied correlations between static and dynamic parameters or those between static parameters and clinical outcomes.
  
  
  METHODS
  Forty patients were evaluated. Clinical outcome was assessed using the Short Form-36 questionnaire, Neck Disability Index, and a Visual Analog Scale. Spineview software (Surgiview, Paris, France) was used to investigate sagittal balance parameters and ROM. The mean follow-up was 24.3 months (range: 12 to 36 mo).
  
  
  RESULTS
  Clinical outcomes were satisfactory. There was a significant improvement of Short Form-36, Neck Disability Index, and Visual Analog Scale scores. Mean ROM was 8.3 degrees preoperatively and 11.0 degrees postoperatively (P=0.013). Mean preoperative C2C7 curvature was 12.8 and 16.0 degrees at last follow-up (P=0.001). Mean preoperative functional spinal unit (FSU) angle was 2.3 and 5.3 degrees postoperatively (P<0.0001). Mean postoperative shell angle was 5.5 degrees. There was a significant correlation between postoperative C2C7 alignment and preoperative C2C7 alignment, change of C2C7 alignment, preoperative and postoperative FSU angle, and prosthesis shell angle. There was also a significant correlation between postoperative FSU angle and preoperative C2C7 alignment, preoperative FSU angle, change of FSU angle, and prosthesis shell angle. Regression analysis showed that prosthesis shell angle and preoperative FSU angle contributed significantly to postoperative FSU angle. Moreover, preoperative C2C7 alignment, preoperative FSU angle, postoperative FSU angle, and prosthesis shell angle contributed significantly to postoperative C2C7 alignment. No significant correlation was observed between ROM and sagittal parameters. Few correlations were found between sagittal alignment and clinical results.
  
  
  CONCLUSIONS
  CDR with this prosthesis provided favorable clinical outcomes and maintains ROM of the FSU, overall and segmental cervical alignment. Long-term follow-up will be needed to assess the effectiveness and advantages of this procedure.
authors: Department of Orthopaedic Surgery, University Hospital of Bordeaux, Spinal Unit, Place Amélie Raba Léon, Bordeaux, France. pguerin_patrick@yahoo.fr
authors: Patrick
authors: P
authors: Guérin
authors: Ibrahim
authors: I
authors: Obeid
authors: Olivier
authors: O
authors: Gille
authors: Anouar
authors: A
authors: Bourghli
authors: Stéphane
authors: S
authors: Luc
authors: Vincent
authors: V
authors: Pointillart
authors: Jean-Marc
authors: JM
authors: Vital
mesh_terms: D000328:Adult; D019643:Arthroplasty, Replacement / Q000379:methods*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D059145:Total Disc Replacement / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult