Osteonecrosis of the Iliac Wing and Sacral Insufficiency Fractures After Radiotherapy: Case Presentation

Abstract

Iliac wing osteonecrosis coexisting with sacral insufficiency fracture rarely causes low back pain. Radiotherapy (RT) applied to the pelvic area is an important precipitating factor. Here, we present a patient who was referred to our outpatient clinic with mechanical lower back pain that was present for 3 months. The patient had received RT to the pelvic region due to colorectal cancer. Contrast-enhanced magnetic resonance imaging studies revealed iliac wing osteonecrosis and sacral insufficiency fracture. After ruling out the possibility of metastasis and making a definitive diagnosis, the patient was followed-up and bed rest and calcium and vitamin D supplementations were recommended. Despite these precautions, the patient still developed another sacral insufficiency fracture. Mechanical low back pain has a myriad of etiologies and standard X-rays may underdiagnose rarer causes of pain, such as osteonecrosis and insufficiency fractures. Clinical suspicion of these entities, especially in patients with a history of RT, may help in diagnosis and treatment.

Keywords

• fracture
• low back pain
• osteonecrosis
• radiotherapy
• rectal neoplasms