Obtain a complete and detailed history and physical examination of the patient, with special emphasis on history of coagulopathy, anticoagulant therapy, and sensory or motor nerve deficits, especially in the territory affected by the surgery and the block(s).

Evaluate indications and determine the absence of contraindications for anesthesia and/or postoperative analgesia. The indications for peripheral nerve blocks include most upper and lower extremity surgery. In addition, thoracic, breast, urologic (e.g., nephrectomy, prostatectomy, cystectomy), and abdominal surgeries (e.g., liver resection, colectomy, pancreatectomy) and hernia repair (inguinal and umbilical) also benefit from the use of paravertebral blocks. These blocks have been demonstrated to be as effective as epidural. The contraindications to regional blocks are local (e.g., infection or trauma, possible preoperative nerve damage), surgical (e.g., nerve repair), related to the patient’s condition (e.g., uncooperative or unwilling, presence of uncontrolled seizure disorder), and related to the surgeon’s preference (unwilling to have his or her patients blocked). Coagulopathy and anticoagulation therapy at the time
of the performance of the block, which are often cited as contraindications to peripheral nerve block anesthesia, should be considered a relative contraindication. Thus, most of the approaches are based on reaching a nerve superficially using a small gauge needle introduced into a groove and allowing compression in the area to be applied. Coagulopathy and anticoagulation therapy at the time of the performance of the block should be considered contraindications when the technique requires the needle to pass into muscular masses and when the nerve is located deep as in the case of a lumbar plexus, any paravertebral approaches, the classic posterior Labat approach to the sciatic nerve, or the anterior approach to the sciatic nerve. However, the use of thromboprophylaxis following surgery is not a contraindication to the performance of a peripheral nerve block prior to the initiation of the thromboprophylaxis.