title: Distraction, Compression, Extension, and Reduction Combined With Joint Remodeling and Extra-articular Distraction: Description of 2 New Modifications for Its Application in Basilar Invagination and Atlantoaxial Dislocation: Prospective Study in 79 Cases.
abstract: BACKGROUND
  Recent strategies for treatment of basilar invagination (BI) and atlantoaxial dislocation (AAD) are based on simultaneous posterior reduction and fixation.
  
  
  OBJECTIVE
  To describe new modifications of the procedure distraction, compression, extension, and reduction (DCER), ie, joint remodeling (JRM) and extra-articular distraction (EAD) in patients with "vertical" joints, and to quantify the improvement in joint indices, ie, sagittal inclination (SI), craniocervical tilt (CCT), and coronal inclination.
  
  
  METHODS
  Prospective study (May 2010 to September 2014). Joint indices measured included (normal values): SI (87.15 ± 5.65°), CCT (60.2 ± 9.2°), and coronal inclination (110.3 ± 4.23°). Surgical procedures included DCER alone (performed in SI <100°, group I) or JRM with DCER (in SI: 100-160°, group II), or EAD with DCER in severe BI with almost vertical joints (SI >160°, group III).
  
  
  RESULTS
  Seventy-nine patients were selected (mean, 22.5 years of age). All conventional indices improved significantly (P < .001). CCT improved in all groups (P < .01); group I (n = 32): 54 ± 8.7° (preoperative 80.71 ± 12.72°); group II (n = 40): 58 ± 7.0° (preoperative 86.5 ± 14°); group III (n = 7): 62 ± 10.0° (preoperative 104 ± 11.2°). SI improved in both group I and II, P < .01 (cannot be measured in group III). At long-term follow-up (n = 64, 29 ± 8 months, range 12-39 months), the Nurick grade improved to 1.5 ± 0.52 (preoperative: 3.4 ± 0.65; P < .001).
  
  
  CONCLUSIONS
  DCER seems to be an effective technique in reducing both BI and AAD. JRM and EAD with DCER are useful in moderate to severe BI and AAD (with SI >100°). Joint indices provide useful information for surgical strategy and planning.
authors: *Departments of Neurosurgery, All India Institute of Medical Sciences (AIIMS), New Delhi, India; ‡Department of Neuroradiology, All India Institute of Medical Sciences (AIIMS), New Delhi, India.
authors: P Sarat
authors: PS
authors: Chandra
authors: Manik
authors: M
authors: Prabhu
authors: Nishant
authors: N
authors: Goyal
authors: Ajay
authors: A
authors: Garg
authors: Avnish
authors: A
authors: Chauhan
authors: Bhawani Shankar
authors: BS
authors: Sharma
mesh_terms: D000328:Adult; D001268:Atlanto-Axial Joint / Q000601:surgery*; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D019857:Osteogenesis, Distraction / Q000379:methods; D010985:Platybasia / Q000601:surgery*; D011446:Prospective Studies; D055815:Young Adult