Maintenance of sagittal plane alignment after surgical correction of spinal deformity in patients with cerebral palsy.

STUDY DESIGN

A case series of patients with cerebral palsy treated for spinal deformity using Luque-Galveston instrumentation was retrospectively analyzed.

OBJECTIVE

To analyze the incidence and risk factors for postoperative loss of sagittal plane correction initially obtained with Luque-Galveston instrumentation in patients with cerebral palsy.

SUMMARY OF BACKGROUND DATA

The Luque-Galveston instrumentation technique has been widely adopted in the treatment of neuromuscular spinal deformity. Although the results in the coronal plane have been generally satisfactory, problems in maintaining sagittal plane correction have been noted.

METHODS

For this study, 41 patients with spastic quadriplegia who underwent surgical correction of spinal deformity between 1990 and 1998 were reviewed with attention given to the maintenance of sagittal plane correction. Preoperative, initial postoperative, and most recent radiographs were measured to determine the sagittal Cobb angle from T5 to T12, T12 to L2, and L1 to S1. On the basis of the preoperative sagittal alignment, patients were separated into two groups: those with preoperative hyperkyphosis (T5-T12 >or= 50 degrees, T12-L2 >or= 20 degrees, or L1-S1 >or= 0 degrees ) and those with normal or decreased kyphosis. The radiographs were assessed for proximal hardware failure/pullout or junctional kyphosis (>20 degrees ), and for backing out of the Galveston rods distally.

RESULTS

Of the 41 patients, 29 underwent correction of their deformity with Luque-Galveston instrumentation alone. In 21 of these patients anterior release-fusion preceded the posterior procedure. Additional anterior lumbar instrumentation was used in 12 patients. Proximal loss of correction or implant failure occurred in 13 patients (32%). In four of these patients junctional kyphosis developed at the cephalad extent of the instrumentation, and nine patients had proximal hardware failure/pullout. Posterior migration of the distal end of the Galveston rods occurred in five patients (12%). Four of these five patients had anterior release and fusion without instrumentation. There were no distal failures in patients for whom anterior lumbar instrumentation was used. All of the patients with distal failure and 11 of 13 patients with proximal failure were considered hyperkyphotic before surgery. The region of hyperkyphosis in the patients that lost distal fixation was most often in the thoracolumbar junction.

CONCLUSIONS

Preoperative hyperkyphosis in the thoracic, thoracolumbar, or lumbar spine was associated with an increased incidence of proximal and distal loss of sagittal plane correction in patients with spastic quadriplegic cerebral palsy treated with Luque-Galveston instrumentation alone. An anterior lumbar release and fusion without instrumentation in a patient with thoracolumbar or lumbar kyphosis increased the risk for posterior pullout of the Galveston rods from the pelvis.