The interscalene block is a regional anesthetic technique usually used in conjunction with sedation or a light general anesthesia for surgeries of the shoulder and upper arm. 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 a 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 relaxes you and will likely cause you to have little or no recollection of the block placement.
Next, the anesthesiologist will cleanse your neck on the operative side with an antiseptic solution. He or she will use both anatomical landmarks and an ultrasound machine to find the desired location for the interscalene block an inch or two above the collarbone on your neck.
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 nerves. In addition to the ultrasound, occasionally, a process called nerve stimulation will used to assist verifying the location of the nerves to your shoulder/upper arm 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 chest, shoulder or arm . 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 to numb your shoulder and arm. This procedure takes only a few minutes to perform.
The block takes approximately 15-20 minutes to work. You will notice shoulder and arm weakness and numbness. Once in the operating room, you will once again be attached to the usual monitors and positioned by the surgeon. You will usually receive a light general anesthetic because it allows for better blood pressure control, and ultimately more patient comfort. Most of the shoulder surgeons prefer general anesthesia to prevent any patient movement during the surgery.
After the surgery and transport to the recovery room, the anesthesia will begin to wear off. Read more about general anethesia here or sedation here. You may notice a few things. First you will have little or no pain. You won't be able to move or feel your shoulder, arm, and sometimes your hand. Your voice may be hoarse and you may feel like you're not taking as deep a breath as you did before the surgery. These are normal expected side effects from the interscalene block and are relatively short lived.
The numbness from the block usually lasts from 10-18 hours. As it begins to wear off, you should start the pain medicine that was prescribed by the surgeon.