Vertebral column decancellation for the management of sharp angular spinal deformity

Abstract

The management goal of sharp angular spinal deformity is to realign the spinal deformity and safely decompress the neurological elements. However, some shortcomings related to current osteotomy treatment for these deformities are still evident. We have developed a new spinal osteotomy technique-vertebral column decancellation (VCD), including multilevel vertebral decancellation, removal of residual disc, osteoclasis of the concave cortex, compression of the convex cortex accompanied by posterior instrumentation with pedicle screws, with the expectation to decrease surgical-related complications. From January 2004 to March 2007, 45 patients (27 males/18 females) with severe sharp angular spinal deformities at our institution underwent VCD. The diagnoses included 29 congenital kyphoscoliosis and 16 Pott's deformity. Preoperative and postoperative radiographic evaluation was performed. Intraoperative, postoperative and general complications were noted. For a kyphosis deformity, an average of 2.2 vertebrae was decancellated (range, 2-4 vertebrae). The mean preoperative kyphosis was +98.6° (range, 82°-138°), and the mean kyphosis in the immediate postoperative period was +16.4° (range, 4°-30°) with an average postoperative correction of +82.2° (range, 61°-124°). For a kyphoscoliosis deformity, the correction rate was 64% in the coronal plane (from 83.4°-30.0°) postoperatively and 32.5° (61% correction) at 2 years' follow-up. In the sagittal plane, the average preoperative curve of 88.5° was corrected to 28.6° immediately after surgery and to 31.0° at 2 years' follow-up. All patients had solid fusion at latest follow-up. Complications were encountered in eight patients (17.8%), including CSF leak (n = 1), deep wound infection (n = 1), epidural hematoma (n = 1), transient neurological deficit (n = 4), and complete paralysis (n = 1). The results of this study show that single-stage posterior VCD is an effective option to manage severe sharp angular spinal deformities.

Figures

Fig. 1

VCR diagrams. a Pedicle screws were inserted before the osteotomy was performed. b A temporary rod was placed to bridge the anterior resection before beginning the posterior osteotomies to provide stability and reduce the chances of sudden spinal translation. c The anterior column was reconstructed with metal mesh filled with cracked bone after the osteotomy; d Realignment was achieved when the posterior column was closed

Fig. 2

VCD diagrams. a Pedicle screws were inserted before the osteotomy was performed. b A high-speed drill was used to decancellate the deformed vertebrae. c Many posterior elements were removed along with the residual disc. d Postoperative lateral view shows that correction is achieved by elongating and opening (arrow) the anterior column and shortening the posterior column, and the residual bone takes the place of metal mesh described in the VCR technique, serving as a “bony cage”

Fig. 3

A 24-year-old patient with Pott’s disease. The patient’s main complaints were low back pain and cosmetic issues. a–d Preoperative X-ray and CT scan reconstruction showed a sharp angle in thoracolumbar spine. e, f Intraoperative picture of a vertebral column decancellation (VCD) was taken at T12 and L1. The VCD was begun with the probe of the pedicle of deformed vertebral body. A high-speed drill was used to enlarge the two pedicle holes. The residual upper and lower cartilaginous endplates and discs, posterior walls of the vertebral body and posterior elements were removed carefully, followed by cantilever technique and pedicle instrument; g, j 3 years’ follow-up X-ray and CT scan show a solid fusion between T12 and L1. k, l Preoperative and postoperative clinical pictures show the improved cosmesis