The Effectiveness of Cryoflow Cooling on Forearm Skin Temperature and Nerve Conduction Velocity in Normal Subjects: A Case-Control Study.

Objectives: The aim of this study was to investigate the effectiveness of Cryoflow cooling on forearm skin temperature and nerve conduction velocity (NCV) in normal subjects. Methods: Thirty male volunteers participated in this study, with a mean age of 20.8 ± 0.74 years. A Cryoflow hose with a nozzle was positioned approximately 10 cm from the forearm and scanned the anterior surface of the non-dominant forearm for 10 min, with temperatures adjusted to -10 °C. Participants' average skin temperature was measured by using an infrared camera. Motor and sensory NCV for both the median and ulnar nerves were measured from both forearms. The dominant side served as a control side. The level of significance was set at p value ≤ 0.05. Results: Following treatment, the experimental group experienced a reduction in average skin temperature, dropping from 32.94 ± 1.11 °C to 16.92 ± 1.68 °C, while the control group showed no significant change. Both the median and ulnar nerves exhibited significant decreases in motor NCV (-10.37 m/s and -8.79 m/s, respectively), alongside slight increases in distal motor latency. Sensory NCV of the median and ulnar nerves decreased significantly (-5.20 m/s and -8.40 m/s, respectively), accompanied by increased onset latency. No significant changes were found in the control group. Conclusions: Cryoflow air-based cryotherapy to the forearm causes a substantial reduction in local skin temperature and significant slowing of peripheral nerve conduction. Both motor and sensory fibers of the median and ulnar nerves exhibited decreased conduction velocities and increased latencies following cooling.