SLCC doesn’t depend on approach
By Mary Ann Porucznik
According to Poster Exhibit P385, spontaneous lumbar curve correction (SLCC) in adolescent idiopathic scoliosis depends less on the surgical approach used than it does on the lowest instrumented vertebra.
The authors note that controversy exists regarding the effect of approach (anterior versus posterior instrumented thoracic fusions) on SLCC for a given compensatory lumbar curve in adolescent idiopathic scoliosis. Their study of 134 anterior and 45 posterior fusions found virtually identical results in SLCC when matched by lowest instrumented vertebra, lumbar curve flexibility, and percentage of thoracic curve correction.
Using the Harms Study Group database, the authors identified 134 anterior and 45 posterior selective thoracic instrumented fusions for Lenke-B or Lenke-C lumbar curves. In each case the distal extent of fusion was either T11, T12, or L1.
Researchers used a one-way ANOVA analysis to directly compare the approaches, then performed a secondary analysis based on factors (curve size, cure flexibility, distal extent of fusion) identified in this study to highly correlate with improved SLCC. This resulted in 28 pairs (one anterior, one posterior approach) of curves that were matched by these factors and re-examined by approach.
The preliminary analysis and correlation studies comparing the groups revealed the strongest correlations for SLCC occurred with lowest instrumented vertebra, lumbar curve flexibility on preoperative bending films, and the percentage of thoracic curve correction.
The secondary analysis of paired curves matched by these criteria revealed no difference in anterior versus posterior approach. An anterior approach resulted in an SLCC of 48 percent; the posterior approach yielded an SLCC of 49 percent (p = 0.75).
Based on this study, researchers suggest that the observed phenomenon of spontaneous lumbar curve correction after selective thoracic fusion in adolescent idiopathic scoliosis is independent of surgical approach and can be reliably achieved with either technique.
The research team includes Peter O. Newton, MD, and Michelle Marks, NMD, both of San Diego; Prerana N. Patel, MD, of Durham, N.C., and Tracey Bastrom, MA and Jeff Pawelek, BS, both of San Diego. Research support was provided by DePuy Spine; Dr. Newton serves as a consultant to and receives royalties from DePuy Spine.