Sacral and Pelvic Insufficiency Fractures Following Adult Spinal Deformity Surgery: A Case Report and Systematic...

Background: Sacral and pelvic insufficiency fractures (SIFs and PIFs) are increasingly recognized yet frequently underdiagnosed complications after adult spinal deformity (ASD) surgery, particularly in patients undergoing long-segment spinal fusion to the sacrum or pelvis. Methods: We present a representative case of sacral and pelvic insufficiency fractures following extensive spinal fusion, highlighting diagnostic and therapeutic challenges. In addition, a systematic review of the literature was performed according to PRISMA guidelines through PubMed, MEDLINE, and Scopus databases, including studies up to December 2024. Data regarding demographics, risk factors, diagnostic modalities, management strategies, and outcomes were extracted and narratively synthesized. Results: A total of 21 studies comprising 89 patients were included. The majority were elderly postmenopausal women with osteoporosis and additional risk factors such as chronic corticosteroid therapy or high body mass index. Diagnosis was frequently delayed due to low sensitivity of plain radiographs, whereas computed tomography was the most reliable modality. Management was surgical in 49 patients (55%)-most commonly extension of fixation to the pelvis or use of S2-alar-iliac screws-with favorable fracture healing reported in most cases. Conservative treatment, employed in 40 patients (45%), included bracing, restricted activity, and bone health optimization, also leading to healing in the majority of cases. Conclusions: Sacral and pelvic insufficiency fractures represent an underrecognized but clinically significant complication after ASD surgery. Early recognition through cross-sectional imaging (CT/MRI) is crucial, and both surgical and conservative approaches can be effective if tailored to patient and fracture characteristics.