Distraction-based surgeries increase thoracic sagittal spine length after ten lengthening surgeries for patients with idiopathic early-onset scoliosis.
STUDY DESIGN
Retrospective, comparative, multicenter.


OBJECTIVES
To determine if the choice of proximal anchor affects thoracic sagittal spine length (SSL) for children with idiopathic early-onset scoliosis (EOS). Debate exists as to whether spine growth is maintained during treatment for EOS. As rib- (RB) and spine-based (SB) distraction procedures may be kyphogenic, the traditional measurement of spine growth on coronal radiographs may not identify out-of-plane increase in spine length. A measure of SSL, along the spine's sagittal arc of curvature, has been validated to reliably assess the length of the thoracic spine.


METHODS
Patients with idiopathic EOS treated with distraction-based systems (minimum 5-year follow-up, five lengthening surgeries) with radiographic analysis preoperatively, postimplant (L1), and during lengthening periods (L2-L5, L6-L10) were evaluated with primary outcome of T1-T12 SSL.


RESULTS
We identified 34 patients (14 RB, 20 SB) with preoperative age 4.9 years (4.2 RB vs. 5.4 SB), scoliosis 72° (60° RB vs. 77° SB; p < 0.05), kyphosis 39° (50° RB vs. 34° SB; p < 0.05), and SSL 17.8 cm (15.5 RB vs. 18.5 SB; p < 0.05). After initial scoliosis correction from implantation, scoliosis remained constant over time. RB patients had greater kyphosis than SB patients: L1, 46° RB vs. 19° SB (p < 0.05); L2-L5, 50° RB vs. 27° SB (p < 0.05); L6-L10, 56° RB vs. 26° SB (p < 0.05). SSL increased for both groups from preoperative to the tenth lengthening (p < 0.05). As compared with RB patients, SB patients had higher SSL preoperatively and maintained this difference to the tenth lengthening (p < 0.05). After ten lengthening surgeries, when normalized to preoperative SSL, relative thoracic growth was greater for RB (27%) than for SB patients (19%) (p < 0.05).


CONCLUSION
Regardless of proximal anchor choice, thoracic length continued to increase during the distraction phase of treatment for idiopathic EOS.


LEVEL OF EVIDENCE
Level III.
['El-Hawary|Ron|R|', 'Chukwunyerenwa|Chukwudi K|CK|', 'Gauthier|Luke E|LE|', 'Spurway|Alan J|AJ|', 'Hilaire|Tricia St|TS|', 'McClung|Anna M|AM|', 'El-Bromboly|Yehia|Y|', 'Johnston|Charles E|CE|', '|||']
D017668:Age of Onset D002675:Child, Preschool D005260:Female D006801:Humans D008297:Male D019857:Osteogenesis, Distraction D012189:Retrospective Studies D012600:Scoliosis D013904:Thoracic Vertebrae
Early-onset scoliosis Sagittal spine length (SSL) Spine growth Three-dimensional true spine length (3D-TSL)