AtlantoAxial Rotatory Fixation: Part 3—A Prospective Study of the Clinical Manifestation, Diagnosis, Management, and Outcome of Children with AlantoAxial Rotatory Fixation
Authors: Pang Dachling , Li Veetai 
Published: November 2005

Abstract

OBJECTIVE:
This is a prospective study of the clinical manifestations, diagnostic motion analysis, management, and outcome of children with atlantoaxial rotatory fixation (AARF).

METHODS:
Fifty children presenting with painful torticollis were subjected to the three-head positions diagnostic computed tomographic scanning protocol described in Part II of our AARF study. Twenty-nine children qualified as having AARF (8 Type I, 11 Type II, and 10 Type III), and six children were classified in the diagnostic gray zone (DGZ). The AARF patients were given either halter or calipers traction depending on the type and chronicity of pretreatment delay. Upon reduction, patients were immobilized with either a cervicothoracic brace or a halo. Recurrence of AARF on halo and patients whose deformity was not reducible were given posterior C1C2 fusion at the best achievable alignment. The difficulty and results of treatment were measured according to the following: duration of traction, number of reduction slippage, percent not reducible by traction, percent needing halo, percent needing fusion, total duration of treatment, total number of treatment procedures, and percent who lost normal C1C2 dynamics. Results were compared between groups stratified by AARF types, by chronicity of pretreatment delay (acute ≪ 1 mo, subacute = 1–3 mo, chronic ≥ 3 mo) and by the presence or absence of recurrence (recurrent AARF defined as having two or more slippages). DGZ patients were treated with only comfort measures for 2 weeks and then restudied. Only those children with persistent symptoms and DGZ or worse motion dynamics were given traction and bracing.

RESULTS:
Neither age nor etiology significantly influenced the severity of AARF. There was only a slight tendency for children younger than 5 years, and for trauma, to associate with severe C1C2 interlock. Delay of treatment up to 11 months did not result in improvement of the neck restriction or in abatement of pain. In fact, there are strong suggestions that prolonged delay could lead to worsening of the rotatory dynamics: Type I AARF are highly correlated with delays longer than 3 months and Type III with delays less than 1 month. Also, four patients who had serial motion studies during the delay period showed clear worsening in the pathological stickiness in C1C2 rotation. In addition, chronic rotatory deformity led to progressive occiput −C1 separation or laxity teleologically to compensate for a skewed visual axis. The mean occiput −C1 separation angle for chronic patients was 31.2° versus 5° for acute patients and less than 3° for normal children. The difficulty and duration of treatment, the number of reslippage after reduction, the rate of irreducibility, the need for halo and fusion, and the percentile of patients ultimately loosing normal C1C2 rotation were significantly greater with Type I patients than Type III patients, with Type II patients being intermediate. Likewise, chronic patients of all AARF types were much worse in all parameters than acute patients; subacute patients were closer to chronic patients in complexity and outcome. Severity and chronicity exerted independent effects on outcome, and the worse identifiable subgroup were the chronic Type I patients versus the best subgroup of acute Type III patients.
Thirteen patients developed recurrent AARF; they had much worse prognosis in all aspects measured than nonrecurrent patients. Recurrence was adversely influenced by both the severity (type) and chronicity of AARF. Half of the DGZ patients resolved with analgesics, but two of six remained symptomatic and in DGZ dynamics, and one deteriorated to Type III AARF. Two of those three patients responded easily to traction and bracing, and one was lost to follow-up.

CONCLUSION:
Children with painful torticollis should be subjected to the three-position computed tomographic diagnostic protocol, not only to secure the diagnosis of AARF but also to grade the severity of the condition by virtue of the dynamic motion curve. Closed reduction with traction should be instituted immediately to avoid the serious consequences of chronic AARF. Proper typing and reckoning of the pretreatment delay are requisites for selecting treatment modalities. Recurrent dislocation and incomplete reduction should be treated with posterior C1C2 fusion in the best achievable alignment. Open reduction and halo immobilization to avoid permanent fixation can be tried with select cases.