LONG–TERM RESULTS FROM IN SITU FUSION FOR CONGENITAL SCOLIOSIS

CJ Goldberg,
DP Moore,
EE Fogarty,
FE Dowling
Children's Research Centre & Orthopaedic Department,
Our Lady's Hospital for Sick Children,
Dublin. Ireland

BACKGROUND:
In situ fusion is the accepted surgical treatment for congenital scoliosis where the anomaly is known to be of high risk for progression, or where increase of Cobb angle has already been documented but cosmesis is acceptable. The aim is to prevent growth of the anomalous region. It was observed that the procedure did not always prevent deformity and either repeat surgery or an unsatisfactory cosmetic outcome sometimes resulted.

OBJECTIVE:
This study examines the incidence of failure, as estimated by repeat surgery, and the possible reasons.

METHODS:
Patients were identified who had been treated for congenital spinal anomalies by in situ fusion as a primary procedure and who were at least 15 years old at last review. Note was taken of subsequent progress and the incidence of repeat surgery.

RESULTS:
There were 299 patients with congenital vertebral anomalies (181, 61% girls; 118, 39% boys). Of these, 161 (96 girls, 53%, and 66 boys, 56%) have had surgery. 71 of these had an in situ fusion and 45 had passed their fifteenth birthday at last review, (24 girls and 21 boys). 15 have had from 1 to 3 repeat procedures for deformity, 10 (41.7%) of the girls and 5 (23.8%) of the boys. Mean age at diagnosis (4.1 years, SD 4.3) and at surgery (7.0 years, SD 4.18) did not differ significantly for boys and girls. Repeat surgery was at a mean age of 13.2 years, SD 4. 1.

DISCUSSION:
There was no clear indication of which anomaly would progress, or the nature of the progression. In some cases, increased rib hump was the main problem, in others shoulder asymmetry and loss of trunk balance. The Cobb angle at the fusion site did not increase, nor was it necessarily the apex of the deformity. Instead, there was a tendency to develop a scoliotic curve that involved a significant segment of initially normal spine. Progression of deformity occurred in tandem with growth rate and was most marked at puberty.

CONCLUSIONS:
While the procedure was usually successful, a substantial minority (1 in 3) have had an unsatisfactory cosmetic result. If localized growth arrest does not prevent deformity in all cases, the question arises as to what is the complete cause of deformity in congenital vertebral anomaly?