Abstract ID: A16
Abstract Title: EVALUATION OF THE RISK OF PUNCTURE COMPLICATIONS DURING ULTRASOUND GUIDED PSOAS COMPARTMENT BLOCK.
Authors: Wiessner D1, Vicent O2, Koch T3, Litz R4
University Hospital Dresden Dresden Saxony Germany1, University Hospital Dresden Dresden Saxony Germany2, University Hospital Dresden Dresden Saxony Germany3, University Hospital Dresden Dresden Saxony Germany4
Poster Type: Either
ABSTRACT BODY
Background and objectives:
Psoas compartment block (PCB) is an effective method for postoperative analgesia in patients undergoing total knee joint replacement (TKJR). However, there is an increasing number of reports concerning serious puncture complication. Such complications include the accidental puncture of the kidneys, due to variable individual location or repiratory-induced motion as well as intracavital, epidural or spinal puncture. Such complications may not be prevented by neurostimulation. Ultrasonic guidance of peripheral nerve blocks was shown to increase block success and minimizing the risk of puncture complications. In contrast to superficial nerve blocks the lumbar plexus can not be visualized by ultrasound. The purpose of the underlying study was to evaluate the risk of accidental renal puncture during PCB performance using neurostimulation and ultrasound.
Methods: 234 consecutive patients undergoing PCB for TKJR were analysed. PCB was performed according to Chayen’s approach using a 150 mm insulated needle (Plexolong, Pajunk, Germany) and neurostimulation. Additionally, an ultrasound probe (3.5 MHz, Sonosite 180 plus, Sonosite, USA) was placed laterally in a mid-axillary line allowing visualisation of the iliac crest, the spine, the psoas muscle and the lower pole of the kidneys and additionally the needle tip during advancement (Fig. 1). The caudal motion of the kidneys was measured as well as the distance between kidney and iliac crest. The final needle location was judged accurate if twitches of the quadriceps femoris muscle were elicitated. With the needle in situ the distances between needle and spine as well as between needle and kidney were measured. After negative aspiration a mixture of 40 ml ropivacaine 0.5% and mepivacaine 1% or prilocaine 1% was injected. For intraoperative analgesia an additional sciatic nerve block according Labat’s approach was performed.
Results: Blocks were sufficient for intraoperative analgesia in 87% of patients. Ultrasonic conditions were judged difficult in 8% of patients due to morbid obesity or intestinal gas so complete measurements could be performed in 215 patients (Fig. 2). The distance between the lower pole of the kidneys and the needle was less than 3 cm in 9% of patients. In 12 patients the kidney was located close to the iliac crest. This was due to variation in kidney location as well as lower pole cysts which are common in the elderly. The needle tip was observed in all patients with good conditions during needle advancement. The spread of the local anesthetic solution could be observed in all of these patients.Twitches of the psoas muscle were observed in all but 4 patients. In 8% of patients aspiration test revealed blood and the needle position was corrected. No puncture complications occurred.
Discussion: Ultrasonic needle guidance during PCB allows visualisation of needle advancement and real-time observation of adjacent structures, which are at risk of accidental puncture. Especially in the elderly, who are the typical cohort of patients undergoing TKJR variation of the anatomy of the kidneys is common. Thus, despite the visualisation of the nerves of the lumbar plexus is not possible, the use of ultrasound may minimize the risk of puncture complications.
ATTACHED FILES
A16_fig 2.tif
Reg Anesth Pain Med 2005; 30(3):A16