The deep peroneal nerve is one of 5 nerves that are often blocked or anesthetized to perform ankle surgery. It can be performed as a regional block and is a great alternative to achieve regional anesthesia for surgery in patients at high risk during general anesthesia. It has minimal risks, reduces complications of wound healing when compared to infiltration anesthesia, and provides better postoperative comfort for the patient. With the rise of ultrasound-guided nerve blockade, there have been reports of longer-lasting and more effective anesthesia. The deep peroneal nerve can also be blocked at the region of innervation for painful injuries such as burns or lacerations. Utilizing this safe and effective technique will aid with analgesia and minimize discomfort while repairing and managing the injury.
The deep peroneal nerve innervates muscles of the anterior leg compartment and the dorsum of the foot. It is also responsible for the sensation of the first interdigital cleft of the foot, or the space between the first and second digits. The nerve is derived from the common peroneal nerve, which originates as the dorsal branches of L4 and L5. In the lower leg, it descends, along with the anterior tibial artery, just anterior to the interosseous membrane. The nerve provides motor innervation to the muscles of the anterior compartment. It tracks along the lateral aspect of the anterior tibial artery and crosses the anterior aspect of the ankle between the extensor hallucis longus and extensor digitorum longus muscles. Approximately 1.3 cm above the ankle joint, the nerve divides into its 2 terminal branches, the lateral and medial branch. The lateral branch passes deep to the extensor digitorum brevis and extensor hallucis brevis muscles and provides their motor innervations. It also provides sensory innervation to the ankle and sinus tarsi. The medial branch courses medially along the dorsum of the foot lateral to the dorsalis pedis artery. The extensor hallucis brevis tendon crosses over the nerve, and the nerve terminates in the first interdigital cleft of the foot where it provides sensory innervation.
Indications for a deep peroneal nerve block include:
Contraindications to a deep peroneal nerve block include:
Equipment for procedure includes:
The practitioner trained in ultrasound-guided regional anesthesia techniques and support staff to administer rescue medications in the event of an adverse reaction.
Obtain informed consent from the patient including risks, benefits, and alternative therapies to the procedure. Verify patient identity with name, date, and MRN and then verify site at which you will be administering the nerve block. Position the patient so that the dorsal surface of their foot and anterior leg are easily accessible. This is best achieved by having the patient lay down in bed with their knees bent and the plantar surfaces of their feet firmly against the bed. Perform a detailed neurovascular exam to the extremity to be blocked. Aseptic technique is used with application of chlorhexidine gluconate 2% or povidone-iodine solution to the skin of the injection site. Apply a sterile ultrasound probe cover and sterile gel to the high-frequency linear probe. Draw up the anesthetic solution in a sterile syringe and have patient's vitals closely monitored.
The nerve block is performed in the following steps:
Blocking the deep peroneal nerve will provide anesthesia to the interdigital cleft between the first and second toes of the foot. While it does not provide a large amount of sensory innervation, it is still important for patients who are undergoing foot or ankle procedures. The increased prevalence of ultrasound has also allowed easy visualization of the nerve and increased success rate of onset to ankle block. While blocking the deep peroneal nerve and the other nerves of the ankle during surgery, it has shown this nerve block can improve outcomes in the patient's pain postoperatively. This nerve block can also be performed successfully using the extensor hallucis brevis musculotendinous junction as an anatomical landmark.
A majority of the time the deep peroneal nerve block is used when performing ankle or foot surgery. As with any surgery, the process is a well-coordinated effort of many staff, in this case specifically the surgeon, anesthesiologist, and nursing staff. For these surgeries, either the surgeon or anesthesiologist places the block and nursing is available with medication for adverse reaction. In a large randomized trial, they found with well-organized care between specialties that there was a low risk of neurologic or nerve block site complications for post-operative complications. (Level 1) It is also important to work closely with pharmacy and nursing during these situations to monitor for local anesthetic systemic toxicity or LAST syndrome. With pharmacy and nursing, they have access and could administer intralipid 20% (1.5 mL/kg bolus, 0.25mg/kg per hour drip) in the case of cardiac arrest due to LAST. These procedures require cohesive team approaches and all members of the team are integral to a successful procedure.