Blast injuries and heterotopic ossification

Abstract

Heterotopic ossification (HO) is perhaps the single most significant obstacle to independence, functional mobility, and return to duty for combat-injured veterans of Operation Enduring Freedom and Operation Iraqi Freedom. Recent research into the cause(s) of HO has been driven by a markedly higher prevalence seen in these wounded warriors than encountered in previous wars or following civilian trauma. To that end, research in both civilian and military laboratories continues to shed light onto the complex mechanisms behind HO formation, including systemic and wound specific factors, cell lineage, and neurogenic inflammation. Of particular interest, non-invasive in vivo testing using Raman spectroscopy may become a feasible modality for early detection, and a wound-specific model designed to detect the early gene transcript signatures associated with HO is being tested. Through a combined effort, the goals of early detection, risk stratification, and development of novel systemic and local prophylaxis may soon be attainable.

Keywords: Amputation; Blast injury; Combat; Ectopic bone; Heterotopic ossification; War wounds.

Figs. 1a - 1b

Radiograph (a) and three-dimensional CT rendering (b) of a patient with severe pelvic heterotopic ossification after bilateral hip disarticulations due to combat-related blast injuries.

Figs. 1a - 1b

Radiograph (a) and three-dimensional CT rendering (b) of a patient with severe pelvic heterotopic ossification after bilateral hip disarticulations due to combat-related blast injuries.

Figs. 2a - 2b

Figure 2a – pre-operative photograph of a medial thigh ulceration in a limb salvage patient with heterotopic ossification (HO) enveloping his femoral vessels and causing secondary knee arthrofibrosis. Figure 2b – clinical photograph of HO ulcerating through the distal aspect of a long transfemoral amputation. Note the skin graft over the terminal portion of the residual limb. Although we advocate avoiding terminal skin grafting of residual limbs whenever practicable, due to the limited available soft-tissue envelope, we are sometimes forced to cover portions of residual limbs with split thickness grafts. Unfortunately, this patient failed conservative therapy and required eventual surgical excision with concomitant resection of the overlying skin graft.

Figs. 2a - 2b

Figure 2a – pre-operative photograph of a medial thigh ulceration in a limb salvage patient with heterotopic ossification (HO) enveloping his femoral vessels and causing secondary knee arthrofibrosis. Figure 2b – clinical photograph of HO ulcerating through the distal aspect of a long transfemoral amputation. Note the skin graft over the terminal portion of the residual limb. Although we advocate avoiding terminal skin grafting of residual limbs whenever practicable, due to the limited available soft-tissue envelope, we are sometimes forced to cover portions of residual limbs with split thickness grafts. Unfortunately, this patient failed conservative therapy and required eventual surgical excision with concomitant resection of the overlying skin graft.