Abstract ID: A34
Abstract Title: Ultrasound as the only nerve localization technique for peripheral nerve block
Poster Type: Poster
ABSTRACT BODY
Ultrasound as the only nerve localization technique for peripheral nerve block
Introduction
Direct ultrasonographic visualization in peripheral regional anesthesia may be an improvement over present techniques.(1)We present two cases of ultrasound guided peripheral nerve block where motor response to nerve stimulation could not be obtained. Direct visualization of the nerves to be blocked allowed successful treatment.
Case 1:
A 42-year-old man was scheduled for secondary closure of a fasciotomy wound after oteosarcoma resection of the femur, femeropopliteal bypass grafting and fasciotomy. Due to this surgery the sciatic nerve was damaged at the level of the distal femur. He was unable to move his foot and suffered from severe neuropathic pain and hyperesthesia in the sciatic nerve distribution. Neuraxial pain treatment was suggested but refused. A subgluteal sciatic nerve block was planned. In Sim’s position the sciatic nerve in the posterior thigh near the gluteal crease was visualized by the Titan ultrasound scanner (Sonosite Ltd, England) with a 5-10 MHz linear transducer. Under direct ultrasound guidance a Stimuplex® insulated needle (B.Braun, Germany) was positioned near the nerve.
Nerve stimulation with 2,2 mA, 1 ms, 1 Hz was necessary to obtain painful sensations in the distribution of the distal sciatic nerve but no motor response was obtained. During the injection of 20 ml of ropivacaine 0.75% circumferential spread of local anesthetic around the nerve was observed. Twenty minutes later the neuropathic pain disappeared.
During surgery sedation was given on request. Both surgery and postoperative course were uneventful. No postoperative pain treatment was necessary until 6 hours after the injection of local anesthetic.
Case 2:
A 51-year-old man was scheduled for re-resection of an arteriovenous malformation of the femur. Twelve years earlier extensive surgery had been performed where skin, quadriceps muscle and patella had been removed, followed by arthrodesis of the knee. The present surgery was performed under spinal anesthesia with 60 mg lidocaine. Two hours after surgery, the patient complained of severe pain in his thigh with a VAS score of 10. Despite 20 mg morphine and 75 mg diclofenac intravenously the pain score decreased to only 6. Epidural pain relief was offered but refused. We therefore decided to perform an ultrasound guided femoral nerve block. For imaging we used the Titan ultrasound scanner (Sonosite Ltd, England) and a 5-10 MHz linear transducer. Guided by ultrasound, a Stimuplex® insulated needle (B.Braun, Germany) was inserted at the inguinal crease and placed in the proximity of the femoral nerve. 15 ml of ropivacaine 0.75% was injected while the spread of local anesthetic around the nerve was followed. Fifteen minutes after injection the pain score decreased to 1 and lasted for 10 hours.
Discussion
These case reportsdemonstrate that ultrasound guidance in the performance of peripheral nerve blocks is useful in patients in whom other nerve localizing techniques may be limited. Ultrasound guidance appears to improve the success and safety of peripheral nerve blocks.
1) Marhofer P, Greher M, Kapral S. Ultrasound guidance in regional anaesthesia. Br J Anaesth 2005;94:7-17.
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A34