The Popliteal Nerve Block in Foot and Ankle Surgery: an Efficient and Anatomical Technique

The popliteal sciatic nerve block is a form of regional anesthesia most commonly used as a form of postoperative analgesia. It has shown to be effective for 15-20 hours postoperatively. It can also be used for various foot and ankle pathologies including fracture and dislocation reduction, exploration of foreign bodies, and bedside incision and drainage. The popliteal sciatic nerve block has an additional benefit in that it decreases amount of postoperative opioid consumption limiting the complications of these medications. There are several techniques in administering this form of anesthesia including a posterior approach for prone patients, or a lateral approach for a supine patient which requires less time. It is physician preference whether the use of single or double injection technique is employed; however, ultrasound guidance and neurostimulation are typically utilized during this procedure. When using neurostimulation, a plantarflexion response is more predictive of complete sensory blockade than a dorsiflexion response. Using ultrasound with neurostimulation has greater efficacy at 60 minutes than using neurostimualtion alone. While this article’s primary purpose is to review the current literature regarding the popliteal sciatic nerve block, the technique employed at our institution is described. Our technique utilizes a lateral approach in the operating room following induction of general anesthesia. Both ultrasound guidance and neurostimulation are used. An assistant holds the leg with the hip slightly flexed and the knee extended to allow for a taut neurovascular bundle. The approach is approximately 5-7 cm cranial to the lateral femoral condyle at a groove between the anterior border of the biceps femoris tendon and the vastus lateralis muscle. The neurostimulation device is set a 1.0 mA and is advanced until a plantarflexion response is noted. A total of 20-30 cc of 0.5% bupivacaine with epinephrine 1:200,000 is injected. The saphenous nerve can be anesthetized between the sartorius and vastus medialis muscles just anterior to the femoral artery. A combination of the popliteal sciatic nerve block and saphenous nerve block has shown to be efficacious in patient satisfaction and pain relief for 24 hours.