One-Stage Hemivertebra Excision via Simultaneous Anterior and Posterior Exposures

Purpose: Hemivertebra excision may be performed as a one or two stage operation via a combined anterior and posterior approach or posterior only approach. The purpose of this study was to evaluate the efficacy of one-stage hemivertebra excision via simultaneous anterior and posterior exposure with wedge resection and unilateral compression instrumentation in young children.

Methods: We performed a retrospective analysis of patient charts and radiographs who underwent one-stage hemivertebra excision at our institution between Jan.1, 1996 and Dec. 31, 2000. To be included in the review the operation performed must have been an isolated hemivertebra excision via a simultaneous anterior and posterior exposure in the lateral decubitus position with unilateral posterior compression (hook-rod construct) instrumentation. We reviewed operative reports to determine the presence of any intraoperative complications as well as reviewed charts to record any post-operative complications. Radiographs were reviewed to determine: hemivertebra location, coronal curve measurements preoperatively and postoperatively, sagittal alignment preoperatively and postoperatively, and the presence of radiographic fusion.

Results: We identified 18 patients treated with simultaneous exposure and wedge resection with instrumentation over the above mentioned time period. The average age was 3.2 yrs.(11 mo.-7.1 yrs.) and the location of the hemivertebra was as follows: 5 thoracic, 5 thoracolumbar, 6 lumbar, 2 lumbosacral. Seven patients had coexisting spinal dysraphism (4 tethered cord, 3 syrinx). The average curve preoperatively was 38 degrees (29-54) and the sagittal profile measurements were 20 degrees thoracic kyphosis (10-38) and 25 degrees lumbar lordosis (11-41). There was one noted intraoperative SSEP monitoring change which resolved with anesthetic changes. There were no postoperative neurologic deficits. There were no intraoperative problems related to spinal instrumentation. The average postoperative curve measured 7 degrees (0-23) and the average time spent in a cast was 2.4 months (6 wks-4 mos.). There were no postoperative wound problems or infections. All patients obtained radiographic fusion at final follow-up which averaged 2 yrs.11 mos. (2 yrs-6 yrs.). The average curve at final follow-up measured 11 degrees (0- 30) which gave a final percent curve correction of 71%. The final sagittal plane measurements were 27 degrees thoracic kyphosis (15-40) and 30 degrees lumbar lordosis (8-44).

Discussion: In our series, hemivertebra excision through this approach was associated with no neurologic complications and afforded excellent correction and fusion in all patients. Simultaneous anterior and posterior exposure allows maximal visualization and control of the spine when performing the excision and we recommend this technique when performing hemivertebra resection via an anterior and posterior approach.