Permanent nerve involvement resulting from inferior alveolar nerve blocks

Background. This is a prospective study of;:patients referred to a tertiary care center with permanent alteration in sensation of the inferior alveola r nerves, lingual nerves or both that could have resulted only from an infe rior alveolar nerve block. Methods, Working with a subject pool of 83 patients, the researchers outlin ed and photographed the area of altered sensation on each patient, tested i t with von Frey's hairs and two-point discrimination and tested temperature sensation and direction sense. Results. Among a study population of 55 women and 28 men with a mean age of 41.2 years, the lingual nerve was affected in 79 percent of patients and t he inferior alveolar nerve in 21 percent of patients. In 47 patients, the c ausative inferior alveolar nerve block was painful when administered, but i n the other 25 patients, it felt like a normal injection. Of the local anes thetic agents used, prilocaine was found to be more frequently linked to ca ses of nerve involvement in this study. Discussion. Occasionally, an inferior alveolar nerve block can result in pe rmanent involvement of the inferior alveolar nerve, lingual nerve or both. The incidence and exact mechanism of involvement still are unknown. By extr apolation from this study, an incidence of anywhere between 1:26,762 and 1: 160,571 inferior alveolar nerve blocks can be surmised to result in this co mplication. A difference in referral rates for male and female patients is difficult to explain. The 36 percent incidence of dysesthesia in the patien ts in this study is of concern. Conclusion. Permanent nerve involvement after receiving an inferior alveola r nerve block is a documented but very rare complication of the inferior al veolar nerve block, and the exact mechanism involved is still unknown. Clinical Implications. Permanent nerve damage can very occasionally occur a s a result of an inferior alveolar nerve block. The exact mechanism is unkn own, and there is no means of prevention. Knowledge of the risks and compli cations of local anesthesia is essential.