Rod Fracture Causing Relief of Back Pain That Developed After Adult Lumbar Degenerative Flat-Back Correction Surgery: A Case Report

A 73-year-old woman underwent deformity correction surgery (anterior lumbar interbody fusion of L2-L3-L4-L5-S1, pedicle subtraction osteotomy at L4, and posterior screw fixation from T10 to the pelvis) due to lumbar degenerative flat-back. Following the operation, the patient experienced pain in her back and buttocks, for which she regularly took medications. She reported frequently feeling a heavy and stretched sensation of pain after the operation in those areas, which made her regret undergoing the operation. However, at 33 months postoperatively, she reported that one day, while getting up from a chair, she felt a crack in her back, which was followed by an improvement in her back and buttock pain; thereafter, she stopped taking pain medications. Follow-up radiography revealed a bilateral rod fracture at the L4–5 level on the right side and at the L3–4 level on the left side. The overall pelvic parameters, except pelvic incidence, slightly changed after the rod fracture. Therefore, the broken rod was replaced and another rod was added to the broken rod area; however, the changed pelvic parameters were not corrected further during the reoperation. Following the reoperation, the patient showed improvements and she no longer required pain medication.