Chronic anterior compartment syndrome (CACS) is a painful condition within one or more musclecompartment(s) in the lower leg. It impedes blood flow and muscular function due to elevatedintramuscular pressure. The diagnostic criteria are the subject of debate. At present, the measurementof intramuscular pressure (IMP) is the accepted method for establishing the diagnosis. The limitationis that it is invasive. This thesis evaluates the ability of near infrared spectroscopy (NIRS), using threedifferent devices, to diagnose CACS by monitoring changes in muscular oxygen saturation during andafter exercise. The aspect of experimentally induced muscle ischemia was also analysed by NIRS. Inaddition, a new method, i.e. patient pain drawing (PPD), was assessed to support the diagnosis ofCACS.One hundred and seventy-six patients were included in Study I, median age 32 years. Onehundred and fifty-nine patients (median age 29 years) and 31 healthy subjects (median age 36 years)were included in Study III. The use of NIRS as a method for diagnosing CACS, by analysing thechanges in muscular oxygen saturation during and after exercise, was evaluated. Twenty healthysubjects (10 women and 10 men), median age 43 years, were recruited for Study II. Two NIRSdevices were used to measure muscle oxygen saturation in healthy human skeletal muscle of the lowerleg. The capability of the two NIRS devices to detect experimentally induced skeletal muscleischaemia in the leg was compared. Study IV comprised 477 consecutive patients with exerciseinducedleg pain, median age 31 years. The study determined the sensitivity, specificity and predictivevalue of patient pain drawing (PPD) in identifying CACS patients. Intra-observer agreement wasassessed.In Studies I and III, the magnitude of intramuscular deoxygenation was shown to be a nonreliablemethod for diagnosing CACS. In Study I, the mean level of oxygenation (relative values)decreased to 33% in patients with CACS and to 34% in patients without CACS (p=0.107). In StudyIII, the deoxygenation at peak exercise was 1% in the CACS patients and 3% in the non-CACSpatients (p=0.003). In Study II, both devices were able to detect experimentally induced skeletalmuscle ischaemia in the leg. Moreover, the INVOS device was shown to be less affected by the skinand subcutaneous tissue thickness than the InSpectra device. Study IV showed that PPD can be used tosupport the diagnosis of CACS. The sensitivity of PPD to identify CACS ranged between 67-75%.When assessing the agreement between the PPD and the gold standard, the correct diagnoses wereestablished in 79% (Observer 1) and 82% (Observer 2) of the CACS patients (n=79).Patients with CACS cannot be distinguished from patients with other causes of exercise-inducedleg pain using NIRS during an exercise test and at rest after an exercise test. The NIRS device,INVOS, is able to detect experimentally induced skeletal muscle ischaemia in the human leg. The useof NIRS may be helpful in detecting leg muscle ischaemia in clinical situations with reduced bloodcirculation. PPD is useful to support the diagnosis of CACS.
展开▼
