Efficacy of Continuous Femoral Nerve Block with Stimulating Catheters Versus Nonstimulating Catheters - A Systematic-Narrative Review

Abstract

A femoral nerve block is simple to perform, has a high rate success, carries a low risk of complications, and it is widely used technique for surgical anesthesia and post-operative pain management of the lower extremity. It provides analgesia to the anterior thigh, including the flexor muscles of the hip and extensor muscles of the knee and therefore, it is well suited for surgeries that involve the hip, the knee or the anterior thigh zone. The femoral nerve block is often associated with sciatic nerve block in order to achieve a lower extremity analgesia. The anterior approach to the femoral nerve block initially described as a 3-in-1 block by Winnie et al (Winnie et al., 1973), suggested that the femoral, lateral femoral cutaneous, and obturator nerves could be blocked from a single paravascular injection at a point inferior to the inguinal crease. Studies have since showed that the femoral can be reliably blocked by a single injection, the lateral femoral cutaneous nerves is blocked in 95%, but the obturator nerve is almost always spared (Parkinson et al., 1989). Therefore, a 3-in-1 block with the paravascular approach seems difficult to obtain, and, as a consequence, when all three nerves need to be anesthetized a posterior lumbar plexus block or a multitruncular block should be performed. The anterior approach to the femoral nerve is similar for “single shot” or continuous nerve blocks. A femoral nerve block can be obtained with single shot of local anesthetic or by using a continuous catheter technique. The localization of the femoral nerve can be obtained by the use of nerve stimulator or with ultrasound guidance. When using single shot technique, the local anesthetic agent is injected through the needle after location of the nerve with the nerve stimulator. When using continuous catheter techniques, the nerve can be stimulated via the needle through which the catheter is placed, or via both the needle and the catheter itself. This narrative review summarizes the evidence derived from randomized controlled trials (RCTs) and retrospective analysis, in order to determine the efficacy of continuous femoral nerve block comparing the use of stimulating catheters with non-stimulating catheters for lower-extremity surgery. Furthermore, we explore the adjunctive use of ultrasonography for femoral nerve block.