MGH Orthopaedic Ambulatory Surgery Center Anesthesia Popliteal Block

Regional Anesthestic Techniques

POPLITEAL BLOCK

The popliteal nerve block is a regional anesthetic technique used 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.

On arrival to the prep area at the ASC the risks and benefits of the procedure will be discussed with you before you sign your consent. 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 belly. He or she will use either anatomical landmarks or an ultrasound machine to find the desired location behind your knee for the block.

Once the optimum location is found, the anesthesiologist will cleanse either the side of your lower thigh or behind your knee with an antiseptic solution. He or she will then numb the skin with some local anesthetic. Next he or she will slowly insert a short needle into that location. As the needle is advanced a very small amount of electrical current will be put through the needle to assist in locating the nerves to your lower leg. Your anesthesiologist may also utilize the ultrasound to guide the needle. You will feel the sensation of involuntary twitches or movements in foot. Don't try to stop these movements because they tell us if we are in the right location with the needle. When the response is optimal the anesthesiologist will inject the long acting Novocain like medicine to numb the lower leg, ankle, and foot.

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. This is a simple under the skin injection near the kneecap or ankle.

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.