Tissue Micrografting as an Enabling Technology for the Treatment of Volumetric Muscle Loss

Alignment with PRMRP Focus Areas: The proposed work is directly in line with the overarching vision of the FY20 PRMRP to improve the health and well-being of all military Service Members, Veterans, and beneficiaries. The proposal addresses the following PRMRP Topic Area of Musculoskeletal Health, specifically defined as 'Research to better understand tissue-specific diseases or injuries (e.g., bone, cartilage, tendon, and/or muscle) with a focus on treatment, recovery, or regeneration.' More specifically, this project seeks to develop a novel device for the procurement of skeletal muscle autograft for use in the treatment of volumetric muscle loss (VML) without chronic effects associated with donor site morbidity.

VML is a type of combat injury that results in massive loss of skeletal muscle such that the injured person may never be able to function in the same way again due to permanent loss of strength and dexterity. While rehabilitation can mediate healing of milder muscle injuries, it is incapable of promoting regrowth of the lost muscle tissue. Therefore, it is of extreme interest to develop treatments for this type of injury that can regrow the essential components of the injured muscles in the body such that strength and dexterity are sufficiently restored to enable return to duty of the Wounded Warrior and ultimately a greater quality of life during and after their service.

One such treatment that is under development uses the patient's own muscle in such a way that it is cut into small fragments and put back into their body at the location of the combat injury. This treatment has already been proven capable of creating new muscle at the site of the injury such that the overall strength of the injured muscle is improved when tested in rats and pigs. The downside of this treatment, however, is its reliance on the patient's own muscle (i.e., robbing Peter to pay Paul). This a problem because a second injury must be created in an otherwise healthy body part to treat the injury. This is known as donor site morbidity. To address this problem, we are proposing a new approach for harvesting the patient's muscle using a large number of very small donor sites created by arrays of microbiopsy needles that the body is naturally able to heal without scarring rather than a single large chunk of muscle. We will first optimize the design of a harvesting device made of a number of small needles that will each collect a small amount of muscle. The performance of the device will then be tested on pigs to determine the healing and performance of the donor site muscle in comparison with traditional muscle flap harvest procedures.

This research represents a significant advancement in the understanding of this underrepresented component of care for severe extremity trauma. If successful, the technology developed through these efforts is primed to transition quickly into clinical practice and has the potential to transform the care and quality of life of Wounded Warriors.