Chapter 26 - Phenol neurolysis for spasticity management in people with spinal cord injury

Abstract

Phenol neurolysis is one of the many treatment options available for the management of spasticity. When indicated in people with spinal cord injury, targeted phenol neurolysis can improve function and prevent secondary complications of poorly controlled spasticity. After the advent of botulinum toxin injections for the management of focal spasticity, which is easier to administer, phenol neurolysis usage declined over the period. However, recently published data suggest that phenol neurolysis can be safely used for effective spasticity management with ultrasound and electrical stimulation guidance. Phenol is typically used in a 3%–6% concentration, with higher concentrations producing longer-lasting effects. Short-term effects accompanied by analgesia are experienced immediately. Long-term effects may last 3–9 months, which depends upon the distance a nerve must re-generate with proximal injections lasting longer. Phenol neurolysis can be performed with anatomic localization, electrical stimulation guidance, or ultrasound guidance. Though a safety dose has not been studied, current literature recommends a maximum dose of 1–1.2g or 20mL of 5%–6% phenol. Common upper extremity targets include the pectoral and thoracodorsal nerves to manage spastic shoulder adductors and internal rotators, and the musculocutaneous nerve motor points to treat spastic elbow flexors. Common lower limb targets include the obturator nerve to the hip adductors, the tibial motor branches to plantar flexors, and sciatic motor branches to the hamstrings. Risks of phenol injection include those associated with any injection as well as dysesthesias and loss of sensation. Severe systemic side effects can occur in the case of intravascular injection but are otherwise extremely rare. Phenol neurolysis is a highly efficacious tool to manage spasticity in people with spinal cord injury. However, precise techniques and knowledge of anatomy are essential to prevent adverse effects.