Calm Those Nerves: An Alternative to Anesthesia for Knee Replacement
March 08, 2005
By: Sydonya Barker for Knee1.com
Because nerves are the body’s sensory channels, nerve blocks do just that—they block pain signals to the brain and allow patients to be pain-free after surgery. This 100-year-old technology provides an appealing alternative to general anesthesia which often leaves patients feeling nauseated, groggy, and dizzy.
The nerve block, also known as a neural blockade, is a fascinating and viable surgical option for patients undergoing particularly painful operations such as total knee replacement. “It basically anesthetizes the incision and nothing else,” says Dr. Eugene Scioscia, department chair and program director at Allegheny General Hospital’s (Pittsburgh, PA) Department of Obstetrics and Gynecology. “It minimizes the need for narcotics, if not eliminating them altogether.”
This form of regional anesthesia has experienced a revival ever since when, in 2000, the Joint Commission on Accreditation of Healthcare Organizations required hospitals to up the effectiveness of post-operative pain-management techniques.
Administered via injection, nerve blocks provide temporary or sustained periods of pain relief. The “single shot” nerve block, in itself successful, often expires before post-operative pain wears away. In 1946, doctors began developing catheter systems to provide continuous post-operative pain management.
The entire procedure lasts between five and ten minutes. Doctors use a mild medicine to help patients relax as they prepare to anesthetize the surgical area. With fluoroscopy, a form of x-ray that produces an image of the treated area on a television monitor, doctors are better able to focus and guide a catheter directly into the particular nerve root of the spinal column connected to the area being treated. Patients start feeling the full effects within 15 minutes.
By injecting anesthetic medicine into the nerves, doctors interrupt the pain-spasm cycle. Nerve blocks prevent receptors from receiving pain messages, and the surgical area, being numb to pain, loses its ability to conduct reflexes.
Because the body eliminates the medicine within hours or weeks, nerve blocks are reversible. The block contains such low concentrations of anesthesia that the patient is able to perform other movements while being medicated.
As with all surgical procedures, nerve blocks involve minor risks and they only work for about 90% of the population, says Dr. Jacques Chelly, director of orthopedic surgery and acute interventional postoperative pain at UPMC Shadyside in Pittsburgh, PA. Some risks worth noting are that some patients develop a small bruise at the site of needle insertion and less than 1% of patients report feeling “pins and needles” in areas treated by nerve blocks. Currently, some experts also suggest that doctors place catheters correctly only about 60% of the time. Furthermore, if some local anesthesia gets into the blood stream, patients may experience increased heart rate, ringing in the ears, or metallic tastes in the mouth. According to the University Health Network in Toronto, Canada, these symptoms, are not harmful and will go away soon.
To some patients, the benefits of nerve blocks outweigh the risks. Sandy Young, 54, of Bethel Park, PA was the first of Dr. Scioscia’s patients to receive a nerve block during her surgery. “It was wonderful,” she said, “I've had surgery before … [and] I’ve had the Demerol and morphine and you’re just kind of out of it for a few days.” But with the nerve block, she continued, she just healed so much better.