PSOAS SHEATH CHEMICAL NEUROLYSIS FOR MANAGEMENT OF INTRACTABLE LEG PAIN FROM METASTATIC LIPOSARCOMA

Case Report: A 56-year-old man with widely metastatic liposarcoma, aft er left lower extremity amputation, complained of severe right lower e xtremity pain. Trials of systemic opioids had resulted in poor pain co ntrol while introducing intolerable dose-limiting side effects. Method s and Results: Initial inpatient management consisted of a lumbar epid ural infusion of a dilute local anesthetic and preservative-free morph ine. This provided satisfactory relief but was discontinued because of recrudescence of phantom limb pain. A lumbar epidural infusion of pre servative-free morphine sulfate was associated with poor pain relief, central nervous system (CNS) side effects, and severe urinary retentio n resulting in acute renal failure. A repeated trial of parental opioi ds provided marginal pain relief with persistent CNS side effects. Che mical neurolysis of the lumbar plexus was performed with 10 ml of 10% aqueous phenol injected into the psoas muscle sheath. The pain gradual ly resolved over a 2-day period without apparent side effects. Motor f unction was preserved, pain was resolved, and as systemic opioids were reduced, cognitive function and overall well-being were improved.