Posterior hemivertebra resection with bisegmental fusion for congenital scoliosis: more than 3 year outcomes and analysis of unanticipated surgeries

Abstract

Purpose: Until now there have been many reports on hemivertebra resection. But there were no large series on the posterior hemivertebra resection with bisegmental fusion. This is a retrospective study to evaluate the surgical outcomes of posterior hemivertebra resection only with bisegmental fusion for congenital scoliosis caused by fully segmented non-incarcerated hemivertebra.

Methods: In our study, 36 consecutive cases (19 males, 17 females) diagnosed with congenital scoliosis, resulting from fully segmented non-incarcerated hemivertebra, treated by posterior hemivertebra resection with bisegmental fusion were investigated retrospectively, with at least a 3 year follow-up period (36-106 months).

Results: The total number of resected hemivertebra was 36. Mean operation time was 188.6 min with average blood loss of 364.2 ml. The segmental scoliosis was corrected from 36.6° to 5.1° with a correction rate of 86.1 %, and segmental kyphosis(difference to normal segmental alignment) from 21.2° to 5.8° at the latest follow-up. The correction rate of the compensatory cranial and caudal curve is 76.4 and 75.1 %. Unanticipated surgeries were performed on eight patients, including one delayed wound healing, two pedicle fractures, one progressive deformity and four implants removals.

Conclusions: Posterior hemivertebra resection with bisegmental fusion allows for early intervention in very young children. Excellent correction can be obtained while the growth potential of the unaffected spine could be preserved well. However, it is not indicated for the hemivertebra between L5 and S1. The most common complication of this procedure is implant failure. Furthermore, in the very young children we noted that although solid fusion could be observed in the fusion level, implants migration may still happen during the time of adolescence, when the height of the body developed rapidly. So a close follow-up is necessary.

Fig. 1

A 3-year-old boy with hemivertebra between T12 and L1, pre operative radiograph showed pronounced segmental scoliosis and kyphosis. Anterior reconstruction with a mesh cage was used to help to correct the kyphosis and decrease the stress of the convex pedicle. The correction was good. And it maintained well during the follow-up

Fig. 2

A 7-year-old boy with hemivertebra between L3 and L4, presenting segmental scoliosis while the compensatory deformities was mild. We performed posterior hemivertebra and instrumentation with monoaxial pedicle screws. The post operative X-ray showed that the correction was excellent. His body height developed from 125 to 177 cm during 76 months follow-up. Although the correction was maintained well, the screws of the upper vertebra migrated downwards. Solid fusion could be noted on the X-ray and CT scan. We removed the implants. The fusion of the posterior elements was confirmed during the surgery. No correction loss was noted on the X-ray, 6 months after implants removal