Spectroscopic Biomarkers for Monitoring Wound Healing and Infection in Combat Wounds

Background: Modern blast injuries are characterized by devastating injury patterns, involving massive zones of injury that violate soft tissue, bone, and neurovascular structures. Up to 80% of surviving victims with combat or blast-related injuries have sustained major extremity trauma. These extremity injuries account for the bulk of the long-term morbidity, medical expenses, and functional deficits experienced by this patient population.Objective/Hypothesis: Our hypothesis is that an integrated approach to clinical spectroscopy and spectroscopic imaging devices will allow for more accurate assessment of tissue perfusion and oxygenation in extremity injuries, providing improved diagnosis and prognosis of the affected tissue. Noninvasive spectroscopic methods might fulfill such a role, particularly Raman spectroscopy (RS), infrared (IR) imaging, near-infrared spectroscopic (NIRS) imaging, and visible reflectance spectroscopic (VRS) imaging. These technologies are capable of monitoring tissue temperature, perfusion, and associated hypoxia, collagen deposition, and development of calcified tissue.Specific Aims/Study Design:1) Characterize light scattering for the wound healing process using VRS, NIRS, IR imaging, and RS in both large animals and combat wounded patients.2) Image various phenotypic characteristics of combat wounds, enabling a more thorough understanding of the wound healing process.3) Connect spectroscopic imaging results of a porcine model of limb ischemia with optimal conditions for limb resuscitation.4) Validate and correlate spectroscopic imaging results with patient outcome as a predictor of successful wound closure.Innovation: While the technologies themselves are not innovative, the combined multimodal and concurrent fashion of implementation, along with the creation of a multivariate wound healing prediction model, is innovative.Military Benefit: Sequelae from these combat injuries remain the major determinants of both return to duty and long-term disability rates. Early complications such as wound infections and delayed wound healing occur in up to 20% of wounds. Heterotopic ossification, considered a late complication, occurs in 64% of patients. Improved assessment of combat wounds naturally leads to improved treatment of the wounds. Faster wound healing times allows soldiers to return to normal routines sooner, not only enhancing the soldier's quality of life, but reducing medical costs as well.Focus Area: This proposal aims to address multiple focus areas of the Fiscal Year 2009 PRORP award mechanism -- identifying optimal indicators of viability for soft tissue and bone and for limb salvage versus amputation, as well as determining which immunomodulators are responsible for local inflammatory processes.