The torsional dystonias constitute a group of motion disorders of
unknown etiology with variable onset, progression, and severity that
frequently result in spinal curvature. Four patients with this uncommon
disorder, with curves averaging 70 degrees (range, 55 to 95 degrees),
underwent surgical correction for progressive spinal deformity. All of them
had improvement in function postoperatively, but there was a high rate of
postoperative complications.