Thigh Ultrasound Used to Identify Frail Elderly Patients with Sarcopenia Undergoing Surgery: A Pilot Study

Computed tomography (CT) scan quantifying skeletal muscle mass is the gold standard tool to identify sarcopenia. Unfortunately, high cost, limited availability, and radiation exposure limit its use. We suggest that ultrasound of the thigh muscle could be an objective, reproducible, portable, and risk-free tool, used as a surrogate to a CT scan, to help identify frail patients with sarcopenia.

We included 49 patients over 64 y old, referred to the acute care surgery service. An ultrasound of thigh muscle thickness was standardized to patient thigh length (U/S_whole/L). CT skeletal muscle index (SMI) was calculated using skeletal muscle surface area of the L3 region divided by height². Frailty status was assessed using the Canadian Study of Healthy Aging Clinical Frailty Scale.

The mean (SD) age was 76 (8) y, and 34% (n = 17) were men. CT-defined sarcopenia was identified in 65% (n = 11) of men and 75% (n = 24) of women. In general, women had longer stay in hospital than men (mean + SD 14 ± 9 versus 7 ± 3 d, P = 0.003). There was a significant positive correlation between thigh U/S_whole/L and CT SMI. There was an inverse correlation between thigh U/S_whole/L and frailty score; a similar relationship was observed between CT SMI and frailty. There was an association between U/S_whole/L and postoperative major complications.

This prospective observational study illustrates that the U/S_whole/L index can be used as a surrogate to CT scan, whereby it can identify elderly frail patients with sarcopenia. Thigh ultrasound should be further tested as an objective tool to assess for stratifying frailty.