Sensibility of the hand is diminished and disabling in children with C5-C6 brachial plexus birth injury

Dept of Neurosurgery | Leiden Nerve Center, Leiden University Medical Center, The Netherlands

SM Buitenhuis, MJA Malessy

Background: To assess the sensibility of the hand in children with a C5-C6 brachial plexus birth injury (BPBI) and assess related dexterity and grip force. Methods: Fifty children with BPBI (30 after nerve surgery) and 25 controls were investigated. Two-point discrimination (2PD), touch-pressure with Semmes-Weinstein monofilaments (SWF) were tested. Additionally, correct localization of a sensory stimulus of each fingertip was assessed. Dexterity was evaluated with a single item from the MABC-2. Grip force was assessed using a Jamar dynamometer. We compared the affected side with the nondominant hand of the control group. Results: The sensibility in thumb and index finger was significantly diminished in the BPBI group for both two-point discrimination (P=0.005 and P=0.014, respectively) and monofilament test (P<0.001). Localization per finger differed significantly for the thumb, index finger, middle finger and ring finger, but not for the little finger. Dexterity was significantly lower in the BPBI group than in control group, (P=0.023). There was a significant difference toward decreasing hand function with decreasing sensibility according to the Semmes-Weinstein test for the thumb (P=0.036). The mean grip force of the affected non-dominant hand of children with BPBI was reduced compared with controls (95N and 123N, respectively, P=0.001). There was no relationship between grip force reduction and sensibility, bimanual use or shoulder external rotation. Conclusions: 1. The sensibility of thumb and index finger in children with an upper plexus lesion (either surgically or conservatively treated) is diminished when tested with 2PD and SWF. This finding is contrary to generally believed. 2. Localization of sensory stimuli was diminished for thumb, index finger, middle finger and ring finger. This finding implies additional subclinical sensory involvement of C7 in the studied patients. 3. Hand function (dexterity and grip force) is diminished in children with an upper BPBI when tested in detail, but not in routine examination. Dexterity was correlated with decreased sensibility.