Pathomechanism of intravertebral clefts in osteoporotic compression fractures of the spine

Background contextIntravertebral cleft (IVC) associated with vertebral collapse is not uncommon in osteoporotic compression fracture. However, the pathomechanism of IVC is poorly understood. Bone ischemia is indicated in the current hypothesis.PurposeTo clarify the pathomechanism of IVC in delayed posttraumatic vertebral collapse, referred to as Kummell's disease.Study designMagnetic resonance (MR) angiography and histology of segmental arteries and vertebral bodies in delayed posttraumatic vertebral collapse were investigated.Patient sampleAll elderly patients admitted to the authors' spine clinic of tertiary referral center for a 105-month period.Outcome measuresAll imaging tests including plain radiographs, computed tomography, and MR angiography were reviewed by authors using a double-blind method. All operations were performed by one experienced surgeon. The statistical data were analyzed using SPSS program.MethodsEvaluations using MR angiography and computed tomography were performed in 22 patients. Twelve of the 22 patients underwent corpectomy and anterior interbody fusion. At operation, segmental artery and bone surrounding IVC were harvested and microscopically evaluated.ResultsMagnetic resonance angiography showed occlusions of bilateral segmental arteries in nine of 22 patients. Seven patients had unilateral occlusion. In six patients, no occlusion was seen. Microscopically, the left segmental arteries of three patients were completely obstructed by thrombosis. Histologic examination of necrotic bone showed fragile trabecular bone and sparse osteocytes.ConclusionsThe findings of thrombosis of the segmental arteries of the vertebral body with IVC could suggest a mechanism by which IVC is formed, and the progressive collapse may develop following osteoporotic spinal fracture.