Study investigating the role of skeletal muscle mass estimation in metastatic spinal cord compression.

Abstract

Age-related loss of functional muscle mass is associated with reduced functional ability and life expectancy. In disseminated cancer, age-related muscle loss may be exacerbated by cachexia and poor nutritional intake, increasing functional decline, morbidity and accelerate death. Patients with spinal metastases frequently present for decompressive surgery with decision to operate based upon functional assessment. A subjective assessment of physical performance has, however, been shown to be a poor indicator of life expectancy in these patients. We aimed to develop an objective measure based upon lean muscle mass to aid decision making, in these individuals, by investigating the association between muscle mass and 1-year survival. Muscle mass was calculated as total psoas area (TPA)/ vertebral body area (VBA), by two independent blinded doctors from CT images, acquired within 7 days of spinal metastases surgery, at the mid L3 vertebral level. Outcome at 1 year following surgery was recorded from a prospectively updated metastatic spinal cord compression database. 86 patients were followed for 1 year, with an overall mortality of 39.5%. Mortality rates at 1 year were significantly high among patients in the lowest quartile of muscle mass, compared with those in the highest quartile (57.1 vs 23.8%, p=0.02). Death within 1 year in individuals with spinal metastases is related to lean muscle mass at presentation. Assessment of lean muscle mass may inform decision to operate in patients with spinal metastases.