Use of Pelvic Incidence as a Guide to Reduction of H-Type Spino-Pelvic Dissociation Injuries

Abstract

Describe the use of a radiographic parameter (pelvic incidence) to assess the sagittal plane reduction of H-type sacral fractures associated with spinopelvic dissociation, and assess the relationship between standing lumbar lordosis to pelvic incidence after spinopelvic dissociation. Retrospective radiographic and clinical review of treatment outcomes for patients with spinopelvic dissociation injuries secondary to H-type sacral fractures. Level I Trauma Center. Pelvic incidence (PI), a radiographic parameter that measures the orientation of the lumbar spine relative to the pelvis, has been shown to have a correlation with the adequacy of surgical reduction as well as the risk of progression of high-grade spondylolisthesis. We used this parameter as a measure of sagittal plane reduction of spinopelvic dissociation injuries. The clinical records and radiographs of five patients with spinopelvic dissociation injuries were reviewed. Radiographic measurements included standing PI and lumbar lordosis (LL). The relationship of lumbar lordosis on pelvic incidence was tested by a regression analysis. Clinical outcome was assessed by the self-reported ability of the patient to comfortably maintain an upright stance. The average follow-up period was 32 (range: 12-53) months. The average final PI was 82 (60-115) degrees. The average final lumbar lordosis was 58.2 (42-77) degrees. LL was found to be significantly related to PI (P < 0.05). One patient with an abnormally high PI had lumbar fatigue with persistent stance. Pelvic incidence is a potentially useful radiographic parameter that can be used to assess the adequacy of sagittal plane reduction in patients with spinopelvic dissociation injuries.