Inguinal paravascular (lumbar plexus) neurolytic block--description of a catheter technique: case report

We provided care for a 47-year-old female with a history of lung carcinoma and bony metastases who sustained a pathologic fracture of the right acetabulum causing severe and uncontrolled pain in the right groin. Her pain was rated as 8-10 on a 10-point visual analog scale (VAS). Her terminal disease and poor surgical risk precluded therapeutic operative intervention. Consequently, a neurolytic block of the lumbar plexus was performed as a palliative measure.

A modified inguinal paravascular (lumbar plexus) block technique was used. A 17-gauge Tuohy needle was inserted in the groin area just lateral to femoral artery and 1 cm below the inguinal ligament. A guide wire was threaded through the needle and subsequently an angiogram catheter was introduced over the wire into the psoas muscle. Radiographic confirmation of the position was obtained, and the catheter was secured in place. A prognostic block using an infusion of 0.25% bupivacaine at 5 mL/h was initiated for the first 2 days. On the third day a neurolytic block with 6% phenol was performed.

Marked pain relief was experienced by the patient (VAS: 0-1). Sensory block in the femoral, lateral femoral cutaneous, and obturator nerve distributions was elicited. Motor weakness in the femoral nerve was demonstrated. Narcotic use was markedly reduced, and the patient was discharged to home in a pain-free state.

This case report supports the feasibility of placing a catheter via a modified anterior inguinal paravascular block technique and its subsequent use for both local anesthetic infusion and neurolytic block of the lumbar plexus.