Regional nerve blocks in everyday pediatric urology: 2. Ultrasound-guided regional anesthetic caudal block

Category: Ankle, Basic Sciences/Biologics Introduction/Purpose: Until recently, many regional anesthetic blocks were performed without the assistance of ultrasound, relying on methods such as anatomical landmarks and nerve stimulation. The use of ultrasound for peripheral nerve blocks has proven extremely useful for improving the efficacy of many regional anesthetic techniques. There remain a few nerve blocks which have lagged in employing the assistance of ultrasound consistently, one of which is the ankle block. This block is commonly utilized for either surgical anesthesia or post-operative analgesia for a variety of foot and ankle procedures. In this study, we compared the accuracy of traditional landmark technique with an ultrasound guided approach for ankle block by assessing the spread of injectate (dye) along the posterior tibial nerve (PTN) in cadaver models. Methods: Ten below-knee cadaver specimens were used for this study. Five were randomly chosen to undergo landmark guided PTN blocks, and five were selected for ultrasound-guided PTN blocks. The landmark technique was performed by identifying the medial malleolus and Achilles tendon and inserting the needle (4 cm long, 21G Braun® Stimuplex) at the midpoint of the two structures, aiming toward the medial malleolus and advancing until bone was contacted. 2 cc of blue acrylic dye was injected at this location. The ultrasound technique was performed with a linear probe identifying the medial malleolus and the PTN. The needle was advanced in-plane with a posterior to anterior trajectory until the tip of the needle was adjacent to the nerve. 2 cc of blue acrylic dye was injected surrounding the nerve. The extremities were then dissected to determine which nerves had been coated with dye. Results: 100% of the ultrasound guided blocks resulted in completely stained PTN with dye. In the landmark group, only 40% of the landmark technique blocks resulted in completely stained PTN with dye. Of the nerves not stained with dye, 2 were noted to have had dye injected posterior to the nerve and 1 was noted to have had dye injected into the flexor digitorum longus tendon. Conclusion: The base of evidence has dramatically increased in recent years in support of the use of ultrasound in regional anesthesia. This study substantiates the superiority of ultrasound guidance for ankle block by demonstrating a 100% success rate amongst the ultrasound guided group.

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Lower Limb Ultrasound Guided Regional Anesthesia

10.1093/med/9780190231804.003.0003 ◽

2016 ◽

Author(s):

Stuart A. Grant ◽

David B Auyong

Keyword(s):

Lower Extremity ◽

Regional Anesthesia ◽

Lower Limb ◽

Clinical Anatomy ◽

Ultrasound Guided ◽

Nerve Blocks ◽

Adductor Canal ◽

Risks And Benefits ◽

Tools And Techniques ◽

Regional Anesthetic

This chapter describes the clinical anatomy relevant to the lower extremities and outlines the tools and techniques used to perform lower extremity ultrasound-guided nerve blocks. The nerve blocks described here include the femoral, lateral femoral cutaneous, adductor canal (selective femoral), saphenous, obturator, lumbar plexus, sciatic (proximal, anterior, and popliteal approaches), (iPACK) and ankle blocks. For each nerve block, the indications, risks, and benefits of the varying approaches are described in detail. The chapter includes step-by-step instructions with illustrations, including cadaver dissections, to allow the operator to perform clinically effective and safe ultrasound-guided lower extremity regional anesthesia. At the conclusion of each block description, a “Pearls” segment highlights important tips gleaned from our clinical experience. This chapter provides the practitioner with thorough instruction and knowledge allowing optimal delivery of regional anesthetic for any lower extremity surgery or trauma.

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