Deep peroneal nerve blockade is used to diagnose and treat pain disorders in the deep peroneal nerve distribution of the foot.
After informed consent is obtained, the patient is placed in a supine position with the foot elevated on a pillow. The patient is prepared in a standard aseptic fashion over an area large enough to allow palpation of landmarks, and sterile technique is used throughout the procedure. A 1-in. (2.5-cm), 25-gauge needle is inserted between the extensor hallucis longus tendon and the anterior tibial tendon, just superior to the level of the malleoli. The extensor hallucis longus tendon can easily be identified by having the patient extend the great toe. If the artery can be palpated, the needle is placed just laterally to the artery. The needle is advanced toward the tibia, and after negative aspiration, 3 to 5 mL of local anesthetic is injected deep to the fascia to block the deep peroneal nerve (see Fig. 67-19).
FIGURE 67-19. Nerve blocks at the ankle. Approach for nerve injection and neural blockade at the ankle.
The deep peroneal nerve travels down the anterior portion of the interosseus membrane of the leg and extends midway between the malleoli onto the dorsum of the foot. At this point, the nerve lies laterally to the extensor hallucis longus tendon and the anterior tibial artery. It supplies motor innervation to the short extensors of the toes and cutaneous innervation to adjacent areas of the first and second toes.
Hematoma and intravascular injection are possible due to the close proximity of the anterior tibial vessels. If an arterial puncture occurs, prolonged direct pressure is usually adequate to prevent the development of a hematoma.