Reduction of Spondylolisthesis with Pedicle Screw Fixation and Transforaminal Lumbar Interbody Fusion

58 Reduction of Spondylolisthesis with Pedicle Screw Fixation and Transforaminal Lumbar Interbody Fusion

Thomas A. St. John and Todd J. Albert

Goals of Surgical Treatment

To decompress and stabilize the spondylolytic defect; reduce the slippage; restore disc space height; restore sagittal alignment.

Diagnosis

Spondylolisthesis is defined as a forward slippage of a lumbar vertebral body most commonly due to an abnormality of the pars interarticularis from a developmental or acquired condition. Activity related pain localized to the lumbar region may be present, and may occasionally radiate to the buttocks and posterior thighs. True radicular symptoms are rare; however, they may be seen with more severe spondylolistheses, and are typically in an L5 distribution. Physical findings are limited with mild degrees of slippage (increased lumbar lordosis). As the disease progresses, patients may develop the classic knees bent/hips flexed stance and gait (secondary to paravertebral spasm and hamstring tightness). Lateral and oblique radiographs of the lumbar spine should illustrate the diagnosis. In spondylolytic spondylolisthesis, the defect in the pars interarticularis is more clearly seen on the oblique views, as represented by a break through the neck of the “Scotty dog.” Computed tomography (CT) scans may be helpful with unilateral defects or to identify sites of neural compression. In the acute stage, single photon emission CT is most sensitive in detecting a stress fracture through the pars before it is apparent radiographically (Fig. 58–1).

Indications for Surgery

Surgical intervention may be necessary when:

1. There is persistent back pain and/or leg pain (usually in an L5 distribution) that interferes with activities of daily living and has not responded to conservative therapy, consisting of activity restriction, physical therapy, and/or bracing.

2. There is significant progression of the slip.

3. The slip is >50 % whether or not the patient is symptomatic.

4. There is progressive postural deformity or gait abnormality

Reduction of the slippage may be considered for:

1. High-grade spondylolistheses (grade III and IV)

2. A significant increase in slippage seen intraoperatively after neural decompression

Contraindications

Reduction should be performed following a complete decompression of the neural elements. Furthermore, reduction techniques that use only posterior distraction systems have been associated with poor results. Posterior distraction/translational systems are preferred. Finally, reduction should not be attempted in patients with spondyloptosis.

Advantages of Reducing a High-Grade Spondylolisthesis

1. Improved cosmesis

2. Restoration of trunk height and sagittal balance

3. Improved buttock and spine contour

4. Nerve root decompression

5. Better milieu for fusion

Procedure

An adequate exposure of the lumbar spine is necessary. A wide release over the lumbar transverse processes and sacral ala is important for the posterior fusion and will aid in the reduction itself. Furthermore, if a reduction and fusion is being performed on an L5-S1 spondylolisthesis, then exposure of L4 is required for placement of a pedicle screw, which will aid in the reduction. This screw may then be removed following reduction or remain if the fusion is to extend to L4 (secondary to a retrolisthesis at L4-L5 or concomitant disc degeneration at this level).