The popliteal nerve block is a regional anesthetic technique used in conjunction with sedation or a light general anesthesia for surgery of the lower leg, ankle and foot. It is a safe and effective block that provides both safe and excellent surgical anesthesia and post-operative pain control.
During a preoperative phone interview the procedure as well as its risks and benefits will be discussed with you in detail. On arrival to the ASC prep area you will be asked to sign your consent for the procedure. You will then be attached to the usual monitors: a blood pressure cuff, a light sensor to measure your blood oxygen level will be attached to your finger, and EKG leads will be placed on your chest. You will receive some sedation through your intravenous prior to placement of the block, which both relax you and will likely cause you to have little or no recollection of the block placement.
Next, the anesthesiologist will position you for the block. You may be asked to remain lying on your back or to turn onto your side or your belly. He or she will then cleanse either the side of your thigh or behind your knee with an antiseptic solution. He or she will use both anatomical landmarks and an ultrasound machine to find the desired location behind your knee for the popliteal block.
Once the best location is found, the anesthesiologist will numb the skin with some local anesthetic. Next he or she will slowly insert a needle the size of a paperclip through the skin. Your anesthesiologist will utilize ultrasound to guide the needle to the proper location near the nerve. In addition to the ultrasound, occasionally, a process called nerve stimulation will be used to assist in verifying the location of the nerves to your lower leg/ankle/foot and optimizing needle placement. If nerve stimulation is used, a very small amount of electrical current will be put through the needle and you will feel the sensation of involuntary twitches or movements in your foot. Don't try to stop these movements because they tell us if we are in the right location with the needle. When the location and/or response is optimal the anesthesiologist will inject the long acting Novocain like medicine in multiple small doses which will numb your lower leg, ankle, and foot. This procedure takes only a few minutes to perform.
Because the popliteal block only numbs up approximately the outer 90% of the lower leg, ankle and foot, the anesthesiologist will also do a saphenous nerve block to numb up the remaining inner part of the lower leg, ankle, or foot. While positioned lying on your back the ultrasound machine will be used to locate the saphenous nerve. The lower inner thigh will be cleansed with an aseptic solution. Once the optimum location is found, the anesthesiologist will numb the skin with some local anesthetic. Next he or she will slowly insert a needle the size of a paperclip through the skin. Your anesthesiologist will utilize ultrasound to guide the needle to the proper location near the nerve. When the location is optimal the anesthesiologist will inject the long acting Novocain like medicine in multiple small doses which will numb your inner lower leg, ankle, and foot. This procedure takes only a few minutes to perform. Alternatively, the anesthesiologist may make a simple injection under the skin near the kneecap or ankle. Both blocks take up to 30 minutes or more to work. You will notice foot and ankle numbness or weakness.
Once in the operating room, you will once again be attached to the usual monitors and positioned by the surgeon. You will receive a relatively deep level of sedation or a light general anesthetic in addition to the popliteal nerve block. It allows for better blood pressure control, and more patient comfort.
After the surgery and transport to the recovery room the sedation or general anesthesia will begin to wear off. First you will have little or no pain in the ankle or foot and secondly you will be unable to move your ankle or foot. You will receive pain medicine in the recovery room, if you need it.
The numbness and weakness from the block usually lasts from 6-18 hrs. As it begins to wear off you should start your pain medicine that was prescribed by the surgeon.