COMPLICATIONS ARISING FROM INFERIOR ALVEOLAR NERVE BLOCK Facial Nerve Palsy

Neurological complications following the administration of a local anaesthetic can be alarming. By reading reports of such incidents, dentists who find themselves in similar situations will be able to reassure their patients and act accordingly. The authors have reviewed the literature for those neurological complications that have been reported and offer an explanation of their aetiology. Examples of complications covered are facial nerve palsy, transient amaurosis, post-injection paraesthesia, Horner’s syndrome, transient paralysis of combined cranial nerves III, IV and VI, sudden unilateral deafness and abducens nerve palsy. A thorough knowledge of the relevant anatomy pertinent to the various injections used in dental surgery is essential and is highlighted in the text. Dent Update 1999; 26: 344-349 Clinical Relevance: Neurological complications can be very alarming and this paper will go some way to familiarizing practitioners with the reported complications and their outcome. number of significant events led to the introduction of local anaesthetics in dentistry. Following the introduction by Alexander Wood, of the hypodermic syringe, Carl Koller , in 1884, discovered that cocaine possessed analgesic properties, and William Halsted, an American surgeon, used a syringe to inject cocaine to anaesthetize the branches of the mandibular nerve for the relief of pain. First reported complications related to these early anaesthetic agents, until safer alternatives were introduced. Alfred Einhorn manufactured procaine in 1905 and lignocaine was subsequently introduced by Nils Lofgren in 1943. There are numerous routes to achieving local anaesthesia in dentistry. ● In the maxilla, infiltrations (e.g. buccal and palatal) are commonly employed, as well as nerve blockade of the posterior superior alveolar and the infraorbital nerves. ● In the mandible there are lingual and buccal nerve infiltrations as well as the inferior alveolar, lingual and mental nerve blocks. Many millions of local anaesthetic cartridges are administered in dentistry each year, yet the neurologically related complications appear to be rarely reported in the literature: over the past 5 years, of 500 reports of complications related to dental anaesthetic, only 40 address neurological side-effects directly. When such complications do occur, early recognition goes some way to allaying the patient’s (as well as the surgeon’s) concerns. This short article will outline the neurological complications related to local anaesthetics in dentistry that have been reported in the literature and, where possible, explain their aetiology. Neurological complications can be divided into: ● those that arise as a direct result of the procedure itself (inferior alveolar nerve block and posterior superior alveolar nerve block); and ● those due to the toxicity of the agents used. COMPLICATIONS ARISING FROM INFERIOR ALVEOLAR NERVE BLOCK