Pelvic fixation is not always necessary in children with cerebral palsy scoliosis treated with growth-friendly instrumentation

Purpose A previous study showed that patients with neuromuscular scoliosis who underwent fusion to L5 had excellent coronal curve correction and improvement in pelvic obliquity (PO) when preoperative L5 tilt was < 15 degrees. Our purpose was to identify indications to exclude the pelvis in children with cerebral palsy (CP) scoliosis treated with growing-friendly instrumentation. Methods In a retrospective cohort study, children with CP scoliosis treated with TGR, MCGR, or VEPTR with minimum 2-year follow-up were identified from a multicenter database. Results 27 patients with distal spine anchors (DSA) and 71 patients with distal pelvic anchors (DPA) placed at the index surgery were analyzed. The DSA group had a lower pre-index PO (9 degrees vs 16 degrees, P = 0.0001). Most recent radiographic data were similar except the DSA patients had a smaller major curve (47 degrees vs 58 degrees, P = 0.038). 6 (22%) DSA patients underwent extension of the instrumentation to the pelvis (DSA-EXT), most commonly at final fusion (5 patients). DSA-EXT patients had a higher pre-index L5 tilt than patients who did not require extension (DSA-NO EXT) (19 degrees vs 10 degrees, P = 0.009). Sub-analysis showed a lower major curve at most recent follow-up in the DSA-EXT group compared to the DPA group (33 degrees vs 58 degrees, P = 0.021). The DSA-EXT group had a higher number of complications per patient compared to the DSA-NO EXT group (2.3 vs 1.1, P = 0.029). Conclusion Pre-index L5 tilt <= 10 degrees and PO < 10 degrees may be indications to exclude the pelvis in children with CP scoliosis treated with growth-friendly instrumentation. DSA may provide better long-term control of the major curve than DPA.