Prognostic Importance of Spinopelvic Parameters in the Assessment of Conservative Treatment in Patients with Spondylolisthesis

STUDY DESIGN: This was a prospective, two-group comparative study. PURPOSE: The present study aimed to determine the importance of the spinopelvic parameters in the causation and progression of spondylolisthesis. OVERVIEW OF LITERATURE: Spondylolisthesis is slippage of one vertebra over the vertebra below. Since the discovery of pelvic incidence (PI) in 1998 in addition to documentation of other parameters in spinopelvic balance, slippage in spondylolisthesis has been attributed to these parameters. Many studies on the Caucasian population have implicated high PI as a causative factor of spondylolisthesis. To the best of our knowledge, no study has described the role of these parameters in the progression of spondylolisthesis. METHODS: The study was conducted in Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India. Seventy-nine patients with spondylolisthesis consented to participate in the study. All patients were advised to undergo conservative treatment and were regularly followed up according to the protocol. Seventy-five asymptomatic volunteers were recruited as a control group. Of the total of 79 patients, 54 were followed up for 6 months, during which 46 improved, eight showed no improvement, and 25 were lost to follow-up. Sagittal spinopelvic parameters were measured by a single observer using the Surgimap spine software ver. 2.1.2 (Nemaris, New York, NY, USA). Parameters measured were PI, pelvic tilt (PT), sacral slope (SS), thoracic kyphosis, and lumbar lordosis. The results from patients and controls were compared using appropriate statistical methods. RESULTS: The normal and spondylolisthesis groups significantly differed with respect to PI, SS, and PT (p<0.001). There were no significant differences in the measured spinopelvic parameters between patients with high- and low-grade spondylolisthesis or between those whose condition improved and those whose condition worsened. CONCLUSIONS: PI, the most important of all spinopelvic parameters, is responsible for the slip in spondylolisthesis, but not for its progression.