Early identification and prevention of acute compartment syndrome using a novel electrical impedance-based muscle-monitoring device

Project SummaryAcute compartment syndrome (ACS) remains one of the most devastating and readily overlooked traumatic musculoskeletal disorders in clinical practice. In this condition, pressure increases in one of the body’s space-limited compartments, due to direct trauma or bone fracture, resulting in injury to all of the compartment’s contents, including muscle and nerve. Once full-blown ACS develops, the consequences are uniformly catastrophic, with permanent tissue destruction, sometimes necessitating amputation. If caught early, procedures can be used to save the limb. A non-invasive technology that can monitor for the development of the condition both in and out of the hospital and even with the patient’s having a cast in place could serve a critical purpose for ACS prevention. One approach that holds substantial potential for this purpose is electrical impedance myography (EIM). In EIM, a weak electrical current is applied to a muscle or group of muscle and the consequent surface voltages measured, providing an index of myofiber health. Previous studies of impedance techniques have demonstrated high sensitivity to tissue ischemia and injury, including intracellular edema and reductions in extracellular space. Thus, we hypothesize that the application of EIM to muscle could serve as a sensitive method for assessing the onset of ACS. Myolex Inc, a Boston-based small business, has as its main interest the design and development of EIM technology for broad medical use. The company in conjunction with Beth Israel Deaconess Medical Center has studied the specific application of EIM technology for the assessment of ACS in a well-established rat model of this disorder. Data collected and analyses completed previously have demonstrated the sensitivity of EIM to the development of ACS. In this Phase 2 SBIR, we plan to extend the success of our early investigations by developing a self-contained, wireless, battery-powered, wearable ACS detector that can even work on a casted limb that we have called the Myolex® mAlertTM. In Specific Aim 1, building upon an already functioning early prototype, we will create a system, that can be placed on a person at risk for ACS to assess the development of the condition. The system will be wireless and small such that it can be applied prior to cast placement and be easily removable once the period of concern has passed. We will test basic functionality in a small group of healthy subjects. In Specific Aim 2, we will apply this system in a porcine model of ACS while simultaneously measuring tissue perfusion pressures and also preforming measurement on the contralateral limb. We anticipate showing the mAlert’s sensitivity to progressing muscle injury and to its improvement after fasciotomy. At the conclusion of this work, Myolex will be well-positioned to test the device in human subjects at risk for developing ACS and achieve ultimate FDA approval.