Variabili tecniche nell’esecuzione dell’anestesia tronculare dei nervi digitali palmari/plantari nel cavallo

Anatomical studies on the palmar and plantar digital nerves (NDP) distribution, clinical trials about the effectiveness of nerve blocks and the availability of modern imaging techniques in equine practice questioned the specificity and the reliability of this diagnostic ancillary test. Aim of this study was to evaluate the influence of the human error and of the operator’s skill on the results of the test; meanwhile, the utility for didactic purpose and the learning curve were evaluated, using parts of limb from slaughtered animals. One experienced (operator 3) and two untrained operators (operators 1 and 2) performed the perineural injections on 50 limbs. A score was assigned to the difficulty, the time of execution and the precision of the inoculation respectively; type and incidence of the errors occurred were also recorded. Statistical analysis of the data concerning 200 injections revealed that frequency and severity of the mistakes of operator 1 were greater both compared to the other untrained operator (operator 2) and to the experienced operator (operator 3); both inexperienced operators made more errors than the skilled operator. The most frequent error was the accidental inoculation into the digital tendon sheath; other errors occurred were the injection into the digital vein, distance of the inoculation from the nerve greater than 5 mm and a poor amount of anaesthetic. Regard to the site of injection, unskilled operators failed more often in performing perineural blocks in the hind limb. Besides, it has been observed for both the untrained operators a gradual and significant reduction in frequency and severity of the errors. Statistic analysis of data demonstrated that the human error influences the test only when performed by unskilled operators. The use of isolated limbs is a valid aid to acquire a correct skill and the learning curve is influenced by individual variable