title: Early halo immobilization of displaced traumatic spondylolisthesis of the axis.
abstract: METHODS
  A retrospective study evaluating early halo immobilization of Types II and IIA hangman's fractures.
  
  
  OBJECTIVE
  To determine the treatment efficacy of early halo immobilization of Type II and IIA hangman's fractures.
  
  
  BACKGROUND
  The treatment of hangman's fractures with traction reduction is well established, but the time required in traction before the institution of halo-vest immobilization is controversial.
  
  
  METHODS
  A retrospective review of all patients admitted to a level one spinal cord injury center between 1986 and 1999 with either a Type II or IIA hangman's fracture was performed. Initial and final radiographs were measured for translation and angulation. The need for reapplication of traction was also recorded.
  
  
  RESULTS
  There were a total of 27 Type II and four Type IIA fractures. Of the Type II fractures, 21 went onto union after early halo immobilization. Six patients required reapplication of traction reduction because of fracture displacement. The Type IIA fractures all progressed to union. The discerning factor between the failure group and the success group was the initial degree of angulation on lateral cervical radiography. The patients requiring reapplication of traction had an initial fracture angulation of 12 degrees or greater.
  
  
  CONCLUSIONS
  Early halo immobilization after traction reduction of Type II and IIA hangman's fractures is an effective method of management. Type II fractures with an angulation of greater than or equal to 12 degrees may require an extended period of traction to ensure adequate long-term fracture alignment.
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA. vaccaro3@yahoo.com
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Vaccaro
authors.forename: Luke
authors.initials: L
authors.lastname: Madigan
authors.forename: Wayne B
authors.initials: WB
authors.lastname: Bauerle
authors.forename: Adam
authors.initials: A
authors.lastname: Blescia
authors.forename: Jerome M
authors.initials: JM
authors.lastname: Cotler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging / Q000293:injuries*; D005260:Female; D005500:Follow-Up Studies; D005592:Fracture Fixation / Q000009:adverse effects / Q000295:instrumentation; D006801:Humans; D007902:Length of Stay; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019838:Neck Injuries / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy; D009984:Orthopedic Fixation Devices / Q000009:adverse effects; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000145:classification / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy; D013124:Spinal Injuries / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014143:Traction; D016896:Treatment Outcome