Spinopelvic Parameters in the Clinical and Functional Outcomes of Patients Submitted to Lumbar Interbody Fusion Surgery – A Prospective Study

Abstract Objectives The relevance of spinopelvic parameters in the patients' clinical and functional outcomes has been widely studied in long spinal fusion. Yet, the importance of the spinopelvic parameters in short-segment fusion surgeries needs further investigation. We analyzed the spinopelvic parameters and surgical outcomes of patients undergoing short-segment lumbar interbody fusion. Materials and Methods An observational, prospective study was conducted between January and June 2021. We selected 25 patients with lumbar stenosis, with or without concomitant spondylolisthesis, undergoing transforaminal lumbar interbody fusion. Variables related to the patient, diagnosis, and surgery were collected. The clinical and functional outcomes were assessed using the Visual Analogue Scale for low-back and leg pain and the Oswestry Disability Index (ODI). The surgical outcomes and spinopelvic parameters were analyzed pre- and postoperatively. Results There was a significant clinical and functional improvement after surgery (p < 0.001), with a mean ODI decrease of 63.6%. The variables of obesity, concomitant spondylolisthesis, absence of osteotomy, and two-level fusion were all associated with lower levels of improvement after surgery (p < 0.05). Pelvic incidence minus lumbar lordosis (PI-LL) was the only parameter that significantly changed regarding the pre- and postoperative periods (p < 0.05). Before surgery, PI-LL < −10° correlates with less low-back pain after surgery (r = 0.435; p < 0.05). Postoperatively, no correlation was found between surgical outcomes and all the spinopelvic parameters analyzed. Conclusions The clinical and functional outcomes significantly improved with the surgical intervention but did not correlate with the change in spinopelvic parameters. Patients with preoperative PI-LL < −10° seem to benefit the most from surgery, showing greater improvement in back pain.