title: Technique for direct posterior reduction in irreducible atlantoaxial dislocation: multi-planar realignment of C1-2.
abstract: OBJECTIVE
  Apart from the commonly seen antero-posterior subluxation of C1 over C2, the dislocation may occur in vertical, lateral or rotational plane. Desired C1-2 realignment can be achieved by corrrecting its dislocation in all planes. We describe a technique for the same.
  
  
  METHODS
  The clinical and radiological features of 16 patients (4 – traumatic and 12 – congenital) with irreducible atlantoaxial dislocation (AAD) admitted in the last 1.5 years were studied. Specific attention was paid to vertical dislocation with lateral and rotational components, apart from anterior-posterior subluxation. They were operated through direct posterior approach. The technique using a long rod holder as lever and screw head (tulip) as fulcrum was employed to achieve C1-2 realignment in all planes. The postoperative clinical and radiological data was analyzed and compared with preoperative data.
  
  
  RESULTS
  Patients presented with progressive myelopathy and/or progressive worsening of neck pain. Vertical dislocation was seen in 11 patients with congenital AAD in addition to the antero-posterior subluxation seen in all. Three patients with traumatic AAD and 8 with congenital AAD had additional lateral dislocation or lateral tilt. Three patients with traumatic AAD and 7 with congenital AAD showed rotational component. Postoperatively, all patients showed clinical improvement.
  
  
  CONCLUSIONS
  The antero-posterior and vertical realignment could be achieved in all except one. Similarly, rotational and lateral components could be completely corrected in 8 out of 10 patients. The technique appears to realign the C1-2 in all planes and provides good anatomical restoration.
authors.affiliation: Neurosurgery, PGIMER, Chandigarh, India. Electronic address: drpravin_salunke@yahoo.co.uk.
authors.forename: Pravin
authors.initials: P
authors.lastname: Salunke
authors.affiliation: Neurosurgery, PGIMER, Chandigarh, India. Electronic address: drsushantsahoo@gmail.com.
authors.forename: Sushanta
authors.initials: S
authors.lastname: Sahoo
authors.affiliation: Radiodiagnosis, PGIMER, Chandigarh, India. Electronic address: nk.khand@gmail.com.
authors.forename: N K
authors.initials: NK
authors.lastname: Khandelwal
authors.affiliation: Radiodiagnosis, PGIMER, Chandigarh, India. Electronic address: dr.msghuman@gmail.com.
authors.forename: Mandeep S
authors.initials: MS
authors.lastname: Ghuman
mesh_terms: D000293:Adolescent; D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D002648:Child; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods*; D011859:Radiography; D016896:Treatment Outcome; D055815:Young Adult
keywords: Atlantoaxial dislocation; Irreducible; Multiplanar; Realignment; Reduction; Technique