Ventral Derotation Spondylodesis: A Review of 22 Cases.OGIELA, DENNIS M. MD; CHAN, DONALD P. K. M DSpine: January/February 1986 Original Article: PDF Only Abstract Twenty-two patients with major lumbar or thoracolumbar curves were treated with Zielke's modification of the Dwyer instrumentation, termed the "ventral derotation spondylodesis (VDS) system. In 16 patients, this was followed by planned second-stage posterior Harrington instrumentation and fusion. Six patients with adolescent idiopathic scoliosis were treated with VDS instrumentation and fusion alone. In neuromuscular and adult idiopathic scoliosis, a combined approach resulted in excellent curve correction and a high rate of successful fusion. In adolescent idiopathic scoliosis, VDS instrumentation alone resulted in excellent curve correction while permitting a shorter fusion length than conventional posterior Harrington instrumentation. (C) Lippincott-Raven Publishers.