Persistent Postoperative Axial Pain Following Lumbar Instrumentation in a Young Woman with Suspected Sacroiliac Pathology: A Longitudinal Case Report from a Remote Settingoiliitis: A Case Report

Abstract

Background: Chronic low back pain after spinal instrumentation remains a difficult clinical dilemma often categorized as Failed Back Surgery Syndrome (FBSS). While workups routinely focus on the instrumented vertebral levels, adjacent pelvic structures and hardware-induced soft-tissue irritation can also serve as primary pain generators.

Case Presentation: Following the CARE guidelines, I describe a 27-year-old woman from rural Sumbawa Island who presented in September 2022 with severe low back and buttock pain (VAS 8/10) and bilateral lower-limb motor weakness (grade 4/5) after lifting a heavy object, against a background of untreated childhood trauma. Preoperative MRI demonstrated normal thoracolumbar alignment without disc herniation or listhesis, but revealed bilateral sacroiliac joint (SIJ) narrowing and subchondral fat metaplasia suggestive of suspected sacroiliitis. After conservative care failed, posterior stabilization from L3 to L5 was performed based on progressive motor deficits and suspected dynamic instability. Following surgery, her radicular leg pain resolved (resting VAS 1/10), but axial lumbosacral pain persisted at VAS 4–5/10 during weight-bearing activities for nearly three years. Physical examination consistently showed bilateral positive Patrick tests. In July 2025, persistent tenderness over the pedicle screws led to elective hardware removal, which reduced her axial pain to VAS 2–3/10.

Conclusion: This case highlights the clinical challenge of evaluating back pain when severe disability clashes with modest supine MRI findings in a rural setting. Clinicians should consider adjacent SIJ overload and hardware irritation before contemplating revision spinal surgery.