Results of complete hemivertebra excision followed by circumferential fusion and anterior or posterior instrumentation in patients with type-IA formation defect.

To evaluate the results of surgical treatment in patients with unlocked full-segmented hemivertebra treated by excision. Twenty-six patients with a mean age of 12.4+/-1.7 years were included in the study. The mean duration of follow-up was 47.8+/-21.9 months. Diagnosis of type-IA hemivertebra was established by clinical, radiological, CT, and MRI evaluation. Preoperatively, patients were randomly allocated into two groups. In the first group, patients underwent anterior hemivertebrectomy initially; this was followed by posterior excision of the hemivertebra, posterior instrumentation, and fusion. In the second group, posterior components of the hemivertebra were excised at first, then the hemivertebra body was excised anteriorly, and this was followed by anterior instrumentation and fusion. For both groups, compression was applied to the convex side while distraction was applied to the concave side. Frontal and sagittal plane analysis of radiograms obtained preoperatively, postoperatively, and after a minimum period of 2 years was performed. The balance was analyzed clinically and radiologically by the measurement of the lateral trunk shift (LT) and shift of head (SH). The mean preoperative and postoperative Cobb angles were 45.5 degrees -/+11.4 degrees and 16.8 degrees -/+7.9 degrees, respectively, and postoperatively, a mean correction rate of 64.4+/-13.9% was obtained (P=0.00). The mean correction rate was 61.2+/-13.3% (19.2 degrees -/+7.6 degrees) for the last follow-up visit. Sagittal plane analysis demonstrated either conservation of physiological sagittal contours or a normalizing effect following excision of hemivertebra combined with anterior or posterior instrumentation. When postoperative balance values were compared, a statistically significant correction was found in terms of LT and SH values. Although none of the patients had complete balance (SH: 0 mm) or balanced curves (0 mm<SH<15 mm) preoperatively, 20 (76.9%) of the patients had a balanced trunk after surgical intervention. Circumferential fusion could be achieved in all cases. No neurological complication developed, the only complication was delayed wound healing. In view of these data, it is concluded that these techniques can be safely used for this patient group at low thoracic, thoracolumbar, and lumbar levels of vertebral column with high correction rates.