PRESSURE IN FINGER TRAPS

Abstract

It is common practice in wrist arthroscopy to suspend the patient’s arm using Chinese finger traps and to distract the wrist joint by applying weight to the arm at the elbow. It is possible that this may cause significant pressure to be applied to the fingers, and potentially damage the digital nerves. We examined the pressure applied by finger traps and consider the risk this poses to the digital nerves.

Standard finger traps were suspended from a spring balance and the author’s fingers inserted along with a length of rubber tubing. The tubing was filled with saline and connected to a digital compartment pressure monitor. The hanging mass was gradually increased and the pressure in the rubber tubing noted. This pressure was taken as analogous to the pressure affecting the neurovascular bundle.

Pressure increases linearly with increasing mass. A pressure of 500mmHg has been suggested as necessary to cause nerve injury1. Using non-invasive technique it was not possible to accurately measure the absolute pressure acting on the digital nerves. However the increase in pressure was noted.

Using weight to distract the wrist during arthroscopy has potential to cause nerve injury. We suggest that pressure insufflation combined with Chinese finger traps with minimum weight traction provides a more than satisfactory view at wrist arthroscopy and can avoid potential digital nerve injury. However traction through finger traps for other purposes such as fracture reduction may be used with caution.