Congenital paediatric atlantoaxial dislocation: clinico-radiological profile and surgical outcome

Congenital atlantoaxial dislocation (AAD) is the most common bony abnormality affecting the craniovertebral junction. The paediatric population has specific problems like preoperative diagnostic difficulties, precise neurological examination, radiological diagnosis, surgical problems including physical fitness to tolerate surgery (including problems of anaesthesia), technical difficulties in surgery and problems related to immobilization.

A total of 229 consecutive paediatric (≤18 years) patients of AAD visited our centre from the period of January 1997 to August 2011. Twenty-nine cases were excluded from the study as these cases were diagnosed as CVJ tuberculosis, 31 cases were excluded as they were traumatic and the remaining 169 cases were retrospectively analysed. These patients were operated by a single experienced surgeon (the senior author) at the Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow. The preoperative and the postoperative clinical evaluation of the patient was done by the Kumar and Kalra myelopathic scoring system. The score was recorded in the preoperative period, at the time of discharge, at 3 months follow-up and at 6 months follow-up.

Ninety-four were males and 75 were females. The age range was 4 to 18 years with mean age 9.96±3.78 years. The follow-up ranged from 3 to 120 months with mean follow-up being 39.03±13.38 months. One hundred five cases were of fixed/irreducible AAD, and 64 were cases of mobile/reducible AAD. Majority of these cases presented with features of pyramidal tract involvement, and 108 cases had compromised pulmonary function test. One hundred thirty-seven cases had improved outcome, and 18 cases were in the same grade in the postoperative period with only 14 cases either deteriorated or died.

Congenital paediatric AAD are a different subset of abnormalities and have a satisfactory outcome. Preoperative evaluation must also include identification of various syndromes associated with paediatric AAD and respiratory reserve. Cormack-Lehane grade can be helpful in selecting borderline cases for postoperative need of tracheostomy. Majority of the cases have a good outcome, and therefore, surgery should be offered even in severe grade.