The correction of pelvic obliquity in patients with cerebral palsy and neuromuscular scoliosis: is there a benefit of anterior release prior to posterior spinal arthrodesis?

STUDY DESIGN

A retrospective study of 61 patients with cerebral palsy (CP) and neuromuscular scoliosis treated by either a combined anterior-posterior spinal arthrodesis or a posterior-only arthrodesis with the unit rod.

OBJECTIVES

Compare coronal and sagittal plane radiographic outcomes in patients undergoing either a combined anterior-posterior spinal fusion (PSF) or a posterior-only fusion with the unit rod for neuromuscular scoliosis in patients with CP.

SUMMARY OF BACKGROUND DATA

Although an anterior release before posterior spinal arthrodesis is commonly done for larger and stiffer neuromuscular curves, it is unclear whether or not an all-posterior construct produces similar correction in pelvic obliquity as that seen with an anterior-posterior spinal fusion.

METHODS

Sixty-one consecutive children with CP and scoliosis were treated at a single institution between 1991 and 2003 with PSF using the unit rod with an anterior release (group A: 19 patients; average = 14.4 years) or without an anterior release (group B: 42 patients; average = 13.7 years). Side-bending, AP, and lateral radiographs were used to assess various sagittal and coronal plane parameters at baseline, after surgery, and at 2 years. RESULTS.: Before surgery, group A had larger major curves (91 degrees A vs. 72 degrees B; P = 0.001), less flexible major curves (21% A vs. 40% B; P = 0.01), with greater pelvic obliquity (26 degrees A vs. 19 degrees B, P = 0.02) than group B. In the subset of patients with a more severe preoperative pelvic obliquity (>20 degrees ), percent correction in pelvic obliquity was equivalent between groups A (71%) and B (74%, P = 0.91). With respect to coronal and sagittal plane radiographic outcomes, there were no significant group differences in major curve correction (58% A vs. 60% B), but group A trended toward greater % correction from preop bending films. At most recent follow-up, there were no differences with respect to loss of curve correction (7.6 A vs. 8.1 degrees B, P = 0.80). The rate of major complications was 26% for both groups, but group A patients had significantly longer operative times.

CONCLUSION

We demonstrate that excellent correction in severe pelvic obliquity can be achieved in smaller, more flexible curves using an all-posterior PSF, and in larger, less flexible curves using an anterior release with PSF.