Lower limb nerve blocks

The proliferation of ultrasound use is changing the approach to regional anaesthesia of the lower limb. Techniques are being developed that provide high-quality postoperative analgesia while minimizing associated motor block that may impair mobilization. Regional anaesthetic techniques also provide significant opioid-sparing benefits (e.g. less sedation, nausea and urinary retention) that are key principles of current enhanced recovery protocols. Ultrasound-guided nerve localization offers several potential advantages when performing femoral, adductor canal, sciatic and ankle blocks; however, neurostimulation remains a useful and widely used aid to lower limb regional anaesthesia practice.     

Lower limb nerve blocks

The proliferation of ultrasound use is changing the approach to regional anaesthesia of the lower limb. Techniques are being developed that provide high-quality postoperative analgesia while minimizing associated motor block that may impair mobilization. Regional anaesthetic techniques also provide significant opioid-sparing benefits (e.g. less sedation, nausea and urinary retention) that are key principles of current enhanced recovery protocols. Ultrasound-guided nerve localization offers several potential advantages when performing femoral, adductor canal, sciatic and ankle blocks; however, neurostimulation remains a useful and widely used aid to lower limb regional anaesthesia practice.     

Lower limb nerve blocks

Lower limb blocks are increasingly used for analgesia for lower limb arthroplasties, either as single-shot or continuous technique. They allow excellent analgesia, encouraging early mobilization, and may reduce hospital stay. Fascia iliacus block for preoperative analgesia for neck of femur, and parasacral sciatic blocks for postamputation pain are two of the newer blocks described in this article. With the increased use of pure regional techniques for foot surgery with either popliteal or ankle blocks, it is an interesting time for lower limb regional anaesthesia.     

Lower limb blocks

Anaesthetists are very properly concerned about postoperative pain relief. Nerve blocks provide excellent analgesia after lower limb surgery. In recent years several aspects have become clearer. First, the 3 in 1 block frequently misses the obturator nerve; second, the separate figure-of-four obturator nerve block is very effective and easily mastered; and third, the Raj (lithotomy) approach to the sciatic nerve is superior to the Labat technique of the 1930s. Lower limb nerve blocks are simpler to perform and more reliable than many textbooks suggest. If the anaesthetist is familiar with femoral, obturator, sciatic, saphenous and ankle blocks then prolonged analgesia can be provided for any lower limb surgery. The introduction of ropivacaine and chirocaine has removed concerns about drug toxicity when large volumes of local anaesthetic are required. In the very high-risk patient it is usually possible to avoid general or neuraxial anaesthesia for lower limb surgery. Lower limb blocks are becoming more widely practised and should be part of every anaesthetist's repertoire.     

Upper limb nerve blocks

Brachial plexus blockade is used for a variety of upper limb surgical procedures. Ultrasound guidance is generally considered to be the gold-standard technique, although large-scale studies examining efficacy and complications of ultrasound-guided techniques compared with nerve stimulation are still needed. Interscalene block remains the approach of choice for shoulder surgery, although phrenic nerve blockade is common even using low volumes of local anaesthetic. Of the currently available studies comparing the other approaches, there seems to be little difference in efficacy between axillary, supraclavicular and infraclavicular approaches for elbow, forearm and hand surgery when equivalent levels of expertise are used. The major features influencing block choice and performance are discussed.     

Upper limb nerve blocks

Brachial plexus blockade is commonly used for a variety of upper limb surgical procedures and the introduction of ultrasound guidance has led to re-evaluation of many of the approaches. Large-scale studies examining both efficacy and complications of ultrasound-guided techniques compared with nerve stimulation are lacking, but there is a growing body of research to support the routine use of ultrasound. Interscalene block remains the approach of choice for shoulder surgery but phrenic nerve blockade remains common, even using low volumes of local anaesthetic. Of the currently available studies comparing the other approaches, there seems to be little difference in efficacy between axillary, supraclavicular and infraclavicular approaches for elbow, forearm and hand surgery when equivalent levels of expertise are used. Recently, the growth of ambulatory surgery has influenced the increased use of peripheral nerve blocks for analgesia. The major features influencing block choice and performance are discussed here.     

Upper limb nerve blocks

Brachial plexus blockade is used for a variety of upper limb surgical procedures. Ultrasound guidance is generally considered to be the gold-standard technique, although large-scale studies examining efficacy and complications of ultrasound-guided techniques compared with nerve stimulation are still needed. Interscalene block remains the approach of choice for shoulder surgery, although phrenic nerve blockade is common even using low volumes of local anaesthetic. Of the currently available studies comparing the other approaches, there seems to be little difference in efficacy between axillary, supraclavicular and infraclavicular approaches for elbow, forearm and hand surgery when equivalent levels of expertise are used. The major features influencing block choice and performance are discussed.     

Upper limb nerve blocks

Regional anaesthesia of the upper limb can be achieved by injecting local anaesthetic solutions into the brachial plexus according to many described techniques. The level at which injections are made into the neurovascular sheath will largely determine the block pattern. Terminal nerves of the brachial plexus can also be blocked further distal than the brachial plexus, either as a sole regional anaesthetic technique, or as a supplement to a brachial plexus block. The popular axillary approach has been the subject of a significant amount of research and it is now largely accepted that multiple-injection techniques provide more complete and reliable analgesia of the arm. A single injection into the plexus using median nerve stimulation often results in insufficient spread of the local anaesthetic to the retroarterial region. This could lead to incomplete anaesthesia because the radial nerve is not blocked. The musculocutaneous nerve also needs to be blocked separately. The advance of ultrasound-guided regional anaesthesia may improve the safety, success rate and ease of performance of some of the methods of brachial plexus block. It has helped the renewed interest in some of the less popular approaches to the brachial plexus, such as the infraclavicular block. However, further research is required to establish the definitive role of ultrasound in this area.     

Lower limb blocks for children

Femoral and lateral cutaneous nerve of the thigh blocks have been performed in a group of 50 children; the method has not previously been described in paediatric practice. The technique was judged to have been successful in 48 (96%) of the children. There were no early or late complications. It is concluded that these blocks are easy to perform, even in small children and infants, and that they can produce reliable postoperative analgesia for a variety of orthopaedic and plastic procedures.     

Lower extremity nerve blocks

Lower extremity nerve blocks have not become as popular as upper extremity blocks for anesthesia; however, the use of lower extremity nerve blocks will become more widespread, as teaching programs are now providing more regional anesthesia experiences for their trainees so that the anesthesia provider will have the familiarity to use these blocks. To increase the enthusiasm among our surgical colleagues, we must begin to use these blocks for surgery, and if the block must be supplemented with local anesthetic or a light general anesthetic, we must educate them that the block is not a failure but a success, as it will provide analgesia after surgery in a method of multimodal pain control. Lower extremity nerve blocks will become more popular when it is realized that they are an effective way of increasing operating room efficiency. Because the block may be placed in an induction room, there is no induction or emergence in the operating room. Patients may be discharged without the need for pain medications, thus lowering the incidence of nausea postoperatively and decreasing PACU and discharge times.     

Distal nerve blocks of the lower limb

This article describes the distal nerve blocks which are usefulfor ankle (popliteal and saphenous nerve block) and foot (ankleblock) surgery. Metatarsal nerve blocks, i.v. regional anaesthesia(Bier's block) and local anaesthetic infiltration for arthroscopyare not considered.     

Applied anatomy for upper limb nerve blocks

The brachial plexus derives from C5, C6, C7, C8 and T1 nerves. It is made up of five roots, between the scalene muscles, three trunks (upper, middle and lower) lying in the posterior triangle, each of which divide into anterior and posterior divisions behind the clavicle to form lateral, medial and posterior cords in the upper axilla. The plexus gives rise to the definitive motor and cutaneous nerve supply to the upper limb. The plexus can be blocked by local anaesthetic infiltration at its root/trunk level in the fascial sheath compartment between the scalenes, or as it crosses the first rib. Block can also be performed around the axillary artery. Peripherally, the nerves may be blocked at the elbow, wrist or finger level.     

Applied anatomy for upper limb nerve blocks

The brachial plexus derives from C5, C6, C7, C8 and T1 nerves. It is made up of five roots, between the scalene muscles, three trunks (upper, middle and lower) lying in the posterior triangle, each of which divide into anterior and posterior divisions behind the clavicle to form lateral, medial and posterior cords in the upper axilla. The plexus gives rise to the definitive motor and cutaneous nerve supply to the upper limb. The plexus can be blocked by local anaesthetic infiltration at its root/trunk level in the fascial sheath compartment between the scalenes, or as it crosses the first rib. Block can also be performed around the axillary artery. Peripherally, the nerves may be blocked at the elbow, wrist or finger level.     

Lower limb nerve injuries in children

The aim of this paper is to emphasize the seriousness of pediatric peripheral nerve injuries of lower limbs and to stress the importance of early exploration of the injured nervous trunk in order to reduce the number of unfavorable outcomes. Among 136 traumatic peripheral nerve injuries in the children we treated, 31 nerve injuries of the lower limbs were observed. Causes of injury and time to recovery were evaluated. The sciatic nerve was involved in 19 cases, peroneal nerve in 11, root avulsions of the spinal cord in 1. We observed complete recovery in 12 cases and incomplete or no recovery at all in 19. The mean time to recovery in patients who underwent surgery was 18 months (range: 1-32). Considering the rate of spontaneous recovery of postinjection nerve injuries of the sciatic nerve and early onset of skeletal deformities, a closed nerve injury of the lower limb with no recovery within 3 months should always undergo surgery, even if complete functional outcome is not always guaranteed.     

Lower extremity nerve blocks in pediatric patients

Pediatric applications of plexus and conduction nerve blocks have increased considerably in recent years, and they have indications in virtually all aspects of surgical and procedural pain, including outpatient surgery, whether the techniques are used in conscious patients or in combination with general anesthesia. Lower-extremity nerve blocks remain underused despite their many advantages in terms of efficacy, safety, and ease with which they can be performed with the help of a nerve stimulator. A major improvement in recent years consists of the development of techniques allowing catheter placement for continuous infusion of local anesthetics. Copyright 2003, Elsevier Science (USA). All rights reserved.