Persistent synchondrosis of a primary sacral ossification center in an adult with low back pain

Persistence of a primary sacral ossification center resulting in synchondrosis in adulthood is rare and can confound diagnostic decision making during patient management.

To present a synchondrosis between the sacral ala and sacral body in a healthy 23-year-old US Marine who had low back pain.

Case report.

Self-report measures included a numerical pain scale and Roland Morris Disability questionnaire; physiological measures included plain film radiography, computed tomography scans, magnetic resonance imaging, and physical examination procedures; and functional measures included the patient's ability to run and sit without pain and to maintain US Marine Corps fitness standards.

The initial management of his low back pain included a course of nonsteroidal anti-inflammatory medication, chiropractic manipulation of the sacroiliac joints and adjacent tissues, and therapeutic exercise. When the patient's condition did not improve as quickly as anticipated, plain X-ray films were ordered; this revealed a vertical cleft in the sacrum at the site of the patient's pain. Further imaging showed the anomalous cleft to be a synchondrosis between the costal element and the centrum of the sacrum. Manual manipulation, physical training, and ergonomic advice were continued.

Pain severity decreased from 7 to 0, and the Roland Morris score decreased from 14 to 1. He could sit for prolonged periods of time and exercise to Marine Corps standards.

It is unlikely that the synchondrosis was the structure responsible for generating the patient's low back pain. However, such an anomaly is clinically relevant because it may mimic a fracture.