Neurolysis in Hansen's Disease

Hansen's disease is marked by involvement of the peripheral nerves, with Ulnar Nerve involvement being most common in the upper limbs. Typically, neurological damage results from infectious neuropathy, caused by direct infection of the nerve by M. leprae, superimposed on the host's immune response, which triggers a local inflammatory process in an attempt to contain the bacteria, associated with local compression of the nerve. This compression is internal, within the nerve, and abscesses may be present (Figure 1); and external, of the nerve.

Thus, the patient evolves with compressive symptoms of the Ulnar Nerve, with loss of sensation of the fifth and Ulnar half ("lateral or external") of the fourth finger, with a loss of dexterity in the hand and the presence of a "claw" of variable severity of these fingers. It is common for patients to have complaints of movements such as crossing the fingers. Pain at the site of compression is also common.

The surgical treatment is performed through the release and neurolysis of the affected nerve. In the case of the Ulnar nerve, a neural release is performed at the level of the elbow (in the cubital tunnel) and wrist (Guyon canal), places where the nerve passes until it reaches the sensibility innervation region in the fingertips and the motor innervation region in the hand. Thus, the nerve is released from these tunnels, and an external neurolysis is performed, which is the removal of scarring (fibrotic) portions that cover the nerve, as a consequence of the process described in the natural history of the disease, according to Figure 2. These scars, or perineural fibroses, are rigid and compress the nerve. An internal microneurolysis is also performed, which is the opening of the nerve membrane, to decompress its fascicles (individual nerve components), which may be compressed by the fibrotic epineurium. In this way, the patient allows the still viable portions of the nerve to regenerate and regain some degree of function, and benefits from pain improvement. Irreversible sequelae can be treated with individualized surgical procedures, depending on the time of evolution and viable structures, such as neurotizations, tendon transfers, soft tissue and bone procedures.