Session IX - Pediatrics and Spine

·Diagnosis and Treatment of Craniocervical Dissociation: One Institution's Experience with 17 Consecutive Survivors over 7 Years

Carlo Bellabarba, MD; Sohail K. Mirza, MD; G. Alexander West, MD; Frederick A. Mann, MD; David W. Newell, MD; Jens R. Chapman, MD; Harborview Medical Center, University of Washington, Seattle, Washington, USA

Purpose: Craniocervical dissociation (CCD) is a highly unstable injury resulting from osteo ligamentous disruption between the occiput and C2, which is frequently cited as incompatible with life. With improved emergent patient retrieval systems, survival to hospital has increased. The purpose of this study was to identify the timing and method of diagnosis, the diagnostic reliability of screening lateral radiographs, the effect of delayed diagnosis, the complications of treatment, and neurologic outcome of this life-threatening condition. We also introduce an injury-severity classification with therapeutic implications.

Methods: Complete retrospective review of medical records and original radiographs of 17 survivors of CCD between 1994 and 2002 were identified through institutional trauma and spine registries. Radiographic and clinical results were evaluated, emphasizing timing of diagnosis, clinical effect of delayed diagnosis, potential clinical or radiographic warning signs, and response to treatment.

Results: A diagnosis of CCD was identified or suspected on the initial lateral cervical spine radiograph for only 2 of the 17 patients (12%), and was made by screening CT scan in only 2 additional patients (12%). Retrospective review of initial lateral radiographs showed an abnormal dens-basion relationship in 16 of 17 (94%) patients. Thirteen patients had a 2-day average delay in diagnosis, which was associated with profound neurologic deterioration in 5 (38%) patients. One patient worsened neurologically after fixation. There were no craniocervical pseudarthroses or hardware failures after a 15-month average follow-up period (minimum 6 months). The mean ASIA motor score of 50 improved to 79, and the number of patients with useful motor function (ASIA D or E) increased from 7 patients (41%) preoperatively to 13 (76%) postoperatively. Consistent preoperative clinical findings were head injury with intracranial hemorrhage (15 patients, 88%), craniofacial trauma (15 patients, 88%), incomplete spinal cord injury with side-to-side asymmetry and involvement of the C5 level (13 patients, 77%), and death at the scene of the motor vehicle crash (67%). Four patients with severe craniocervical instability had less than 3 mm displacement on preoperative imaging studies. We therefore adopted a classification system based on traction testing of minimally displaced injuries (<3 mm displacement) when craniocervical stability is in question. Treatment is dictated by these results.

Table: Classification of Craniocervical Injuries

Stage	Description of injury	Treatment
1	MRI evidence of injury to craniocervical osseoligamentous stabilizers. Craniocervical alignment within 2 mm of normal. Distraction of 2 mm or less on provocative traction radiograph	Closed
2	MRI evidence of injury to craniocervical osseoligamentous stabilizers. Craniocervical alignment within 2 mm of normal. Distraction of more than 2 mm on provocative traction radiograph.	O-C Fusion
3	Craniocervical malalignment of more than 2 mm on static radiographic studies.	O-C Fusion

Shaded area defined as craniocervical "dissociation."

Conclusions: Diagnosis of craniocervical dissociation was frequently delayed, increasing the risk of neurologic decline. Early diagnosis and stabilization protected against worsening spinal cord injury. However, diagnosis was delayed in the majority of patients. This study highlights the importance of disciplined evaluation of the lateral cervical spine radiograph in assessing polytraumatized patients. A more systematic approach to the evaluation of screening lateral cervical spine radiographs in these frequently head-injured, polytraumatized patients would have raised suspicions about craniocervical instability in all but one patient. Traction testing is valuable in assessing craniocervical stability in minimally displaced injuries. Head-injured patients with overt signs of craniofacial trauma and asymmetric high cervical spinal cord injuries in particular should heighten clinicians' suspicion of craniocervical instability.