INTERCOMPARTMENTAL TISSUE OXIMETRY: A NOVEL NONINVASIVE APPROACH FOR DIAGNOSING CHRONIC EXERTIONAL COMPARTMENT SYNDROME

Chronic Exertional Compartment Syndrome (CECS) affects athletes, military personnel, and workers, causing progressive leg pain during physical activity, which limits their performance and functionality. This condition arises due to an abnormal, progressive increase in intra-compartmental pressure (ICP) within one or more leg compartments, resulting in impaired tissue perfusion, oxygenation, muscle ischemia, pain, and dysfunction. Effective management of CECS depends on early and accurate diagnosis. Current diagnostic standards rely on clinical assessment supported by ICP measurements, which involve invasive needle insertion into leg compartments during or after exercise to track ICP changes. However, there is a clear need for a reliable, non-invasive diagnostic method that directly addresses the pathophysiological mechanisms of CECS. The primary goal of our research project is to assess the feasibility, effectiveness, and accuracy of an optical technique of near-infrared spectroscopy (NIRS) for non-invasive diagnosis of lower leg CECS. Specifically, this study aims to measure baseline tissue oxygenation percentage index (TOI) in the anterior leg compartment and track TOI changes following a standard protocol of 10-minute treadmill exercise in asymptomatic adults, comparing these metrics with those of symptomatic CECS patients. We measured the TOI of the anterior leg compartment in 65 legs of 34 asymptomatic adults without CECS using a wireless, transcutaneous NIRS sensor. Measurements were taken before, during, and after a 10-minute treadmill jogging protocol at a moderate pace (6 km/h, 10% incline). Data analysis provided baseline TOI values, exercise-induced TOI changes, and recovery TOI levels, establishing reference values in asymptomatic individuals. These values were then compared with TOI metrics from a symptomatic CECS patient cohort referred to our clinic. In asymptomatic participants, the mean baseline TOI in the anterior compartment was 68.8% (±4), with a mean post-exercise TOI increase of +2% (±3.6, p = 0.00002) and a mean recovery TOI of 71.9% (±5.3). In symptomatic CECS patients, baseline, post-exercise, and recovery TOI values averaged 71.2% (±1.8), −4.1% (±0.8), and 74% (±2.7), respectively. The following figure shows a representative case. Advanced NIRS shows promise as a feasible, non-invasive technique for assessing tissue oxygenation in the anterior compartment. The intracompartmental tissue oxygenation values observed in asymptomatic participants fall within the normal range (60–75%) reported in the literature. Successful completion of this project will introduce a practical, non-invasive , and cost-effective intervention method, serving as an alternative to the current ICP measurement technique for the rapid diagnosis of chronic exertional compartment syndrome in clinical office settings. Further research is required to validate these findings and to introduce a novel diagnostic approach to CECS. For any figures or tables, please contact authors directly.