Carpal Tunnel Injections: A Novel Approach Based on Wrist Width.

Abstract

Carpal tunnel steroid injections (CTIs) have the potential risk of damaging underlying critical structures, including the median nerve (MN), radial artery (RA), and ulnar neurovascular bundle (UB). The purpose of this study was to analyze the safety of a volar radial (VR) and volar ulnar (VU) CTI, using standardized anatomical "safe zones." This study was performed on 87 cadaveric arms using a percentage of the total wrist width as a guide for placement of a VR (30 and 33% of total wrist width) and VU (60 and 66% of total wrist width) injection. Our results demonstrate a wide range of anatomic variations in the location of these critical neurovascular structures near the carpal canal, indicating that using superficial landmarks alone for CTIs may result in an increased risk of iatrogenic injury to these critical structures. We propose a technique using a percentage of total wrist width as a guide for CTIs. Both VR (30% of wrist width) and VU (60% of wrist width) CTIs offer relatively safe and reliable CTI locations to the carpal canal. Not applicable/cadaveric study.