Hand sensation may be largely preserved when lesions affect upper root of brachial plexus

Bertelli JA. Microsurgery. Published online: Oct. 11, 2010. doi:10.1002/micr.20832.

Overlapping of the dermatomal zones in brachial plexus injuries is more widespread than previously reported, according to the results of a prospective study.

In their research, Jayme Augusto Bertelli, MD, PhD, of Governador Celso Ramos Hospital, in Florianópolis, Brazil, and colleagues matched sensory assessments and pain complaints of patients with CT myelo scan findings and surgical observations. Their study included 150 patients with supraclavicular stretch injury of the brachial plexus who underwent surgery within an average of 5.4 months of injury. The researchers used the Semmes-Weinstein monofilaments to perform preoperative evaluations of upper limb sensation. They recorded each patient’s pain complaints.

The researchers noted that when the lesion affected the upper root of the brachial plexus, hand sensation was largely preserved. They identified sensory disturbances over a longitudinal bundle on the lateral arm and forearm. With C8-T1 root injuries, they saw diminished protective sensation on the ulnar aspect of the hand. They found impaired sensation in the long finger, as well, if the C7 root was also injured.

Sixty-four patients had a total palsy; 84% of them reported pain vs. 47% of the 72 patients with upper-type palsies. Twenty-nine percent of the 14 patients with a lower-type palsy reported pain.

When the C8 and T1 roots were injured, they were always avulsed from the cord. If root avulsion was the only nerve injury, patients did not report pain. Hand sensation was largely preserved in patients with partial brachial plexus injuries, particularly those on the radial side. Hand sensation was mostly preserved even when T1 was the only preserved root, which indicates that dermatomal zone overlapping is more widespread than previously reported, the authors wrote.