New Onset Sacroiliac Joint Pain After Transforaminal Interbody Fusion: What Are the Culprits?

STUDY DESIGN: A retrospective case-control study. OBJECTIVE: Only a few studies have studied the incidence of new-onset SI joint pain following lumbar spine fusion surgery. We aimed to explore the association between new-onset SI joint pain following Transforaminal Lumbar Interbody Fusion (TLIF) for degenerative spine disorders and changes in spinopelvic parameters. METHODS: A retrospective review of hospital records and imaging database of a tertiary care institute was done for patients who underwent TLIF from October 2018 to October 2019. The 354 patients who satisfied the eligibility criteria were divided into 2 groups(Group A, new-onset SI joint pain group, n = 34 and Group B, normal controls, n = 320). Symptomatic relief (>70% reduction in the VAS [Visual Analogue Scale] score) after 15 minutes of SI joint injection was considered diagnostic of SI joint pain. Clinical and radiological spinopelvic parameters were compared between the 2 groups. RESULTS: Patients with postoperative SI joint pain (Group A) had significantly less preoperative and postoperative lumbar lordosis (p < 0.001) compared to the other group. Most of the patients in Group A had a cephalad migration of the apex postoperatively (30/34 patients) whereas majority of patients in group B had either predominant caudal migration (44/320 patients) or no migration of the lumbar apex (272/320 patients). CONCLUSIONS: The preoperative and postoperative lumbar lordosis are significantly less and the postoperative pelvic tilt is significantly high in patients with new-onset SI joint pain compared to the control group. The cephalad migration of the lumbar apex is significantly associated with new-onset SI joint pain.