Volumetric Muscle Loss (VML) Repair Following Extremity Trauma

The exact incidence of volumetric muscle loss (VML) following combat trauma is unknown and has not been rigorously assessed. Estimates from civilian trauma indicate that ~250,000 open fractures occur per year in the US, and these commonly involve a component of VML injury. In the military, a study of battlefield injuries in 14,500 Service members evacuated from OEF/OIF from 2001-2013 suggests high VML incidence. Approximately 77% had musculoskeletal injuries and many had open soft tissue extremity wounds. Roughly 8% of all medically evacuated patients received a disability rating specifically for VML injury. The estimated life-time disability cost per patient is $340,000-440,000 in addition to medical costs and lost wages.

Recovery is uniformly poor, leading to significant long term disability, and leading to increased rates of delayed amputation of technically salvageable, but functionally deficient limbs. There is no agreed upon standard of care for this condition, and no clinically available therapy that can address the loss of function for this condition. The current standard of care for VML involves the use of free muscle transfer (i.e., muscle flaps) for bone coverage followed by extensive physical rehabilitation. However, most muscle flap procedures are not intended to restore muscle function except in limited circumstances. Functional muscle transfer, including vasculature and innervation, has been shown to improve strength to an injured muscle group. However, such procedures require a level of surgical expertise available only in limited, specialized centers.

It is unlikely that there will be a single solution for VML repair. Interventions will likely be required along the continuum of care, beginning close to the point of injury or during initial damage control surgery. In the course of market research, multiple products have been identified which may potentially prevent additional muscle loss and stimulate a repair response early in the course of injury. Such products may be highly valuable in a prolonged field care situation. Such interventions may offer significant improvements over currently limited treatment options.

The focus of this MTEC program is to develop an advanced off-the-shelf prototype capable of preventing, mitigating or treating traumatic large-VML injuries along the continuum of care. The prototype must be able to repair injured muscle tissue to a degree suitable for extremity repair and reconstruction. This program specifically sought projects focused on repurposing products already commercially available or in clinical development for related indications, such as critical limb ischemia, iatrogenic muscle injuries, Duchene’s muscular dystrophy, compartment syndrome, and severe sports medicine injuries. Products capable of regenerating or repairing multiple tissue types or creating a therapeutic wound environment were also considered.

The goal of the MTEC awards is to develop a prototype through proof-of-concept for VML treatment (first in a rodent model, then in a large animal model), with an option to continue product development to relevant supplemental FDA marketing approval/licensure. Support included subject matter expertise, consultation and funding to develop regulatory strategy, conduct animal bridging studies, clinical trials and/or improve efficiency and reproducibility of the manufacturing process at scale to support the desired military indication.

The research project award recipients were selected from the Offerors who responded to MTEC’s Request for Project Proposals (19-03-VML).