Reduced Arterial Circulation to the Legs in Spinal Cord Injury as a Cause of Skin Breakdown Lesions

Abstract

Skin breakdown lesions (SBLs) of the legs are common in spinal cord injury (SCI). It is assumed that the cause is deficient sensitivity and immobility of the limbs, which result in areas subjected to prolonged pressures. However, poor circulation may also be a significant factor. Indeed, strong reasons suggest that small vessel circulation is decreased in SCI because these patients have increased arteriosclerotic risk factors. Patients in the SCI population have advanced age, are sedentary, often have abnormal carbohydrate and lipid metabolism, and many use tobacco products. Total blood flow (TBF) to the legs and skin blood flows (SBFs) to 4 areas of the feet were measured simultaneously by duplex Doppler sonography and laser Doppler flowmetry in 10 healthy control and 10 chronic subjects with SCI when supine and during 30 minutes in a wheelchair. The average supine control TBF was 540 mL/minute, but greatly reduced between 24—76 mL/minute in 4 of the subjects. During sitting, the average TBF fell by 41% in the controls and increased by 6% in SCI. Nonetheless, in all control and SCI subjects the average sitting SBFs were severely decreased in all areas between 53—75%, similar to results found by others elsewhere in the foreleg. Ischemia of the skin and underlying muscles is important as a cause for the poor healing of SBLs in persons with SCI who daily spend many hours in a wheelchair.