Spinal shortening and monosegmental posterior spondylodesis in the management of dorsal and lumbar unstable injuries

Abstract

Introduction: Patients with spinal injuries have been treated in the past by laminectomy in an attempt to decompress the spinal cord. The results have shown insignificant improvement or even a worsening of neurologic function and decreased stability without effectively removing the anterior bone and disc fragments compressing the spinal cord. The primary indication for anterior decompression and grafting is narrowing of the spinal canal with neurologic deficits that cannot be resolved by any other approach. One must think of subsequent surgical intervention for increased stability and compressive posterior fusion with short-armed internal fixators.

Aim: To analyze the results and efficacy of spinal shortening combined with interbody fusion technique for the management of dorsal and lumbar unstable injuries.

Materials and methods: Twenty-three patients with traumatic fractures and or fracture-dislocation of dorsolumbar spine with neurologic deficit are presented. All had radiologic evidence of spinal cord or cauda equina compression, with either paraplegia or paraparesis. Patients underwent recapping laminoplasty in the thoracic or lumbar spine for decompression of spinal cord. The T-saw was used for division of the posterior elements. After decompression of the cord and removal of the extruded bone fragments and disc material, the excised laminae were replaced exactly in situ to their original anatomic position. Then application of a compression force via monosegmental transpedicular fixation was done, allowing vertebral end-plate compression and interbody fusion.

Results: Lateral Cobb angle (T(10)-L(2)) was reduced from 26 to 4 degrees after surgery. The shortened vertebral body united and no or minimal loss of correction was seen. The preoperative vertebral kyphosis averaged +17 degrees and was corrected to +7 degrees at follow-up with the sagittal index improving from 0.59 to 0.86. The segmental local kyphosis was reduced from +15 degrees to -3 degrees. Radiography demonstrated anatomically correct reconstruction in all patients, as well as solid fusion.

Conclusion: This technique permits circumferential decompression of the spinal cord through a posterior approach and posterior interbody fusion.

Keywords: Injury; laminoplasty; shortening; spine; spondylodesis.

Figure 1

A photo showed the T-saw passed through the nerve root canal on both sides

Figure 2

A photo showed the surgical field after the lamina was removed in one piece. The operative field was so wide that it enabled us to manipulate the spine anteriorly and removing the disc material with the retropulsed fragment

Figure 3

A photo showed the lamina in its place fixed temporarily with two K wires

Figure 4

A photo showed the final transpedicular fixation

Figure 5

A plain and MRI radiograph of a female patient aged 29 years with fracture-dislocation at T11– T12 level with complete paraplegia

Figure 6

Postoperative radiograph of the same patient showed monosegmental fixation with transpedicular screw fixation