Neurovascular Entrapment Due to Combat-Related Heterotopic Ossification in the Lower Extremity

Abstract

Heterotopic ossification is the ectopic formation of mature lamellar bone in nonosseous tissue. The prevalence of heterotopic ossification following combat injuries is much higher than civilian data would suggest. In certain cases, the aberrant bone formation can envelop major neurovascular structures in the lower extremity, leading to symptomatic neurovascular entrapment. We describe five consecutive cases of heterotopic ossification leading to symptomatic neurovascular entrapment in the lower extremity as a result of blast trauma and present our method of patient assessment, preoperative planning, and surgical excision. Heterotopic bone was successfully excised without neurovascular injury in all patients. At a mean of twenty months (range, eight to forty-five months) postoperatively, all patients demonstrated continued improvement of their pre-excision function. All patients who had neuropathic pain had a decrease in the pain. Those with decreased joint motion regained motion once their wounds were stable. Sensory deficits resolved before motor deficits did. There was no recurrence of clinically relevant heterotopic ossification in this series. Excision of heterotopic bone, particularly with concurrent neurovascular entrapment, can be associated with major short-term and long-term complications. With use of our treatment algorithm, involving careful preoperative planning and meticulous operative excision, heterotopic bone entrapping major neurovascular structures following severe extremity trauma can be safely excised with subsequent clinical improvement.