A cadaveric and radiologic assessment of catheter placement for the measurement of forearm compartment pressures.

The diagnosis of compartment syndrome is essentially a clinical one. In recent years, much interest and research has focused on the development of intracompartmental pressure monitoring devices to help in the diagnosis of this condition. Proper placement of the catheter is essential for accurate monitoring, because an incorrect result is potentially more dangerous than no reading at all. In the forearm, measurement in the flexor digitorum profundus is thought to be a more sensitive way of assessing rising pressure. One of the risks of catheter placement is inadvertent damage to a neurovascular structure, particularly when monitoring pressures in deeper muscle bellies. Standard anatomic texts and outpatient magnetic resonance scans of the forearm were studied to define a safe pathway for the introduction of a catheter into the volar forearm. An approach from the midline to the ulna, between the tendons of the flexor carpi radialis and palmaris longus, seemed the safest. Ten cadaveric forearms had 100 cc of gastrograffin injected into the deep forearm through a dorsal approach. The median and ulnar nerves were cannulated with a fine wire from the elbow to the wrist. Two cannulae were passed, using the suggested approach, at 2 locations between the wrist and the mid forearm. All limbs then were scanned with computed tomography, and the images were reviewed. In all forearms, the cannulae passed between the median and ulnar nerves into the belly of the flexor digitorum profundus and posed no risk to the neurovascular structures.