Local analgesia

Since the mid-1970s, the use of local anaesthesia by podiatrists has been a routine part of practice and has facilitated the application of many techniques that have been developed to the benefit of the patient. The methods employed range from local infiltration of the anaesthetic agent at the site of the lesion to nerve trunk block techniques that prevent sensory stimulus from the area of the foot the nerve supplies. The choice of method and site of injection depend on factors that are in the best interests of the patient and allow the lowest dosage of anaesthetic agent to be used. A single site on the weight-bearing plantar surface will generally involve blocking the tibial nerve, whereas a single site on the dorsum can be anaesthetized by local infiltration. However, techniques can be employed whereby local infiltration is used on the plantar surface or is delivered by injecting towards the plantar between the metatarsal heads. Multiple sites on the dorsum may be better anaesthetized by a block of the nerve that supplies the area, which could be the sural, saphenous, deep or superficial peroneal. If both of the latter are to be blocked, it is better practice to block the common peroneal nerve, but it should be remembered that this might also affect motor function in the leg even if the total dosage of the agent used is closely controlled and kept to a minimum. CHAPTER CONTENTS