When longer relief is needed, the surgeon may place a tiny catheter next to the nerve and connect it to a pump to administer an anesthetic for up to three days after surgery. “What you get is a way to extend the anesthesia or the numbing effect of the local anesthetic longer than the chemistry of just doing a single shot, making people more comfortable in the first painful days after surgery,” he says.

Some research suggests that people who have regional and local anesthesia experience less pain than those who have general anesthesia only, because they provide preemptive pain control – in essence, they stop pain before it starts, says Dr. Konowitz. “There is all sorts of literature that shows the nerves do better and pain control is better if the nerves are blocked and the brain doesn’t get the message of surgery going on.”

There is also evidence that people who have nerve blocks are less likely to experience a problem called complex regional pain syndrome, in which trauma to the nerve, such as that which can occur with surgery, leads to long-term pain. “In those cases the joint may look good but they end up with more pain than when they started,” says Dr. Konowitz.

Beyond Pain Relief

But improved pain relief is not the only benefit of regional and local analgesia. Research shows these newer techniques may also offer these other direct or indirect benefits over general anesthesia:

Less need for narcotic analgesics. For people, who have had joint surgery, the use of narcotics for post-surgical pain relief can cause a number of unwanted side effects, including grogginess, nausea and vomiting. In a recent review of 10 studies of femoral nerve blocks for total knee replacement published in the journal Anesthesiology, use of the blocks was found to reduce narcotic consumption at 24 and 48 hours after surgery. “Because numbing the nerves keeps people more comfortable the first few days after surgery, when pain is typically at its worst, some are able to avoid narcotics completely,” says Dr. Konowitz, who often uses regional nerve blocks for many joint surgeries. “Some patients tell me they never get their [painkiller] prescriptions filled.”  When the analgesia wears off, the pain may be manageable with milder analgesics and nonsteroidal anti-inflammatory drugs, he says.

Less blood loss during surgery. General anesthetics can cause veins to dilate, which increases bleeding risk during surgery. Studies of people having total hip replacement have shown that those receiving regional anesthesia have approximately 30 percent less blood loss compared to those having the procedure under general anesthesia. A 2006 study in the Canadian Journal of Surgery found that people who had regional analgesia for total hip replacement were also significantly less likely to require blood transfusions those having general anesthesia.

Reduced risks from immobility. Being immobile after surgery can lead to a range of problems including lung problems and blood clots. Regional and local anesthetics may help reduce this risk by enabling patients to be active sooner, says William J. Hopkinson, MD, professor and vice chairman of reconstructive surgery and joint replacement at Loyola University of Chicago and chief of orthopaedic surgery at Edward Hines, Jr. VA Hospital. “Any time people can use their limbs earlier and get up and walk earlier that alone reduces lung problems and breathing issues and the development of other problems, because they can get up and get around and get vertical and start moving,” says Dr. Hopkinson. “The quicker you walk the less likely you are to get a blood clot.”