Sacroiliac Coalition: First Description and Report of a Successful Resection.

Study Design Case report. Objective This report describes the first case of a sacroiliac coalition, its clinical features, the diagnostic difficulties, and the surgical treatment chosen in this case. Methods A 33-year-old man presented to our outpatient clinics complaining of severe left-sided low back pain with an intermitted nondermatomal radiation into the left thigh. The only abnormality on a pelvic radiograph was a coin-size, faint hyperdensity, which was almost overlooked. Subsequent computed tomography (CT) and magnetic resonance imaging (MRI) confirmed two bridging bone spurs on the anterior surface of the left joint with a fibrous interruption at the apex. After the conservative treatment failed, a surgical treatment was offered to the patient. The coalition was resected via an anterior retroperitoneal approach and through the tissue plane between the psoas and the iliacus muscles. A histopathologic examination was performed and confirmed the diagnosis of a coalition. Results The patient's pain resolved immediately after surgery. After 8 months, a follow-up CT scan showed complete removal of the coalition without any signs of recurrence, and at 12 months' follow-up, the patient remained pain-free. Conclusions This is the first published case of a sacroiliac coalition. The only sign of this rare condition on the plain radiographs was very easy to miss. As has been discussed in the literature, CT and MRI are important in the differential diagnostics of such lesions. The histopathologic findings included that of a fibrous bar, confirming the diagnosis, which is further corroborated by the complete resolution of the symptoms.