The nerve damage may be related to direct trauma with the needle or inadvertent intra-neural injection. High injection pressure of local anesthetic (AL) is an indicator that further characterize the location of the needle in terms of tissue density. In clinical practice, local anesthetic injection pressure monitoring is performed manually or by a pressure transducer according to the availability of the equipment or preferences of clinicians. To date, no comparative study has measured the advantages of this measure during PNB.