Growing-rod graduates: lessons learned from ninety-nine patients who completed lengthening.

BACKGROUND

Growing-rod spinal instrumentation systems are a valuable tool for managing severe early-onset scoliosis. There is little information about the end point of treatment.

METHODS

A multicenter early-onset-scoliosis database was searched to identify patients who had undergone treatment with growing rods and either had had a final operative procedure or were still being treated with the growing rods after reaching skeletal maturity (defined as fourteen years of age or older). Clinical, radiographic, and operative data were analyzed.

RESULTS

Ninety-nine patients met the inclusion criteria, and ninety-two (93%) of them had had a final operative procedure. The remaining seven patients (7%) were older than fourteen years but had not undergone a final procedure. Of the ninety-two patients who had a final procedure, seventy-nine (86%) had an instrumented fusion, nine (10%) had growing-rod exchanges and fusion in situ, three (3%) had the growing rods left in place and fusion in situ, and one (1%) had only growing-rod removal. The mean age (and standard deviation) at the final fusion was 12.4 ± 1.9 years. In forty-four (55%) of eighty patients for whom the information was available, the number of vertebral levels fused was the same as the number of vertebral levels spanned by the growing rods. The percent correction of the curve after final fusion was none or minimal (≤ 20 %) in eleven (18%) of the sixty-two patients for whom sufficient-quality radiographs were available, moderate (21% to 50%) in thirty (48%), and substantial (≥ 51 %) in nine (15%); the curve had worsened in twelve patients (19%). The mean duration of growing-rod treatment was 5.0 ± 2.6 years. Of fifty-eight operative reports made at final fusion that contained comments on spinal flexibility, eleven (19%) described the spine as being mobile, eleven (19%) described decreased flexibility, and thirty-six (62%) described the spine as being completely stiff. At final fusion, twenty-two patients (24%) had osteotomies and seven patients (8%) had a thoracoplasty.

CONCLUSIONS

Most patients underwent growing-rod removal and final instrumented fusion. The final fusion often included the same levels spanned by the growing rods and usually achieved <50% additional correction of the deformity remaining at the end of the growing-rod management.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.