Sacral insufficiency fracture after partial sacrectomy

A 66-year-old woman presented with severe lower back pain. Magnetic resonance imaging (MRI) revealed a large, soft-tissue mass-a chordoma-at the S3-S4 level, eroding most of the S3 vertebral body and extending into S4. The mass extended beyond the involved sacrococcygeal segments and dorsally beyond normal cortical margins of the sacrum and coccyx. The patient underwent a noninstrumented sacrectomy distal to the S2 foramen, lumbar laminectomy L5, S1 and S2, and thecal sac transaction at the S3 nerve roots. At the third postoperative month, she noted onset of extreme pain in her groin and left thigh. MRI showed increased signal on short tau inversion recovery sequences, and T2-weighted images revealed a left sacral ala stress fracture with a vertically oriented fracture line. Over the next 3 months, the patient had a resolution of her pain and, at 2-year follow-up, the patient remained disease-free. Surgeons contemplating performing partial sacrectomies should bear in mind, even with preservation of the S1 body, that the potential for fracture exists as evidenced by our patient. It is our opinion that this patient did not require instrumentation but a more gradual rehabilitation program.