November 1, 2007 Anesthesiologists use ultrasound to locate peripheral nerves, then inject a nerve numbing medication into the area. A single injection leaves a limb numb for several hours or a day. The medication is a local anesthetic, but the precise point of administration allows pain-free surgery without losing consciousness and allowing patients to breathe without assistance.
Going under the knife means going under first with anesthesia. With the side effects often associated with it, some people are choosing a more direct approach to block the pain.
For Paul Tomasini, this surgery has been a long time coming. After years of dealing with crippling arthritis in his feet, Paul is finally getting some relief. The pain was so bad Paul had trouble staying on his feet. Not good, since he owns his own contracting business. The only shoes he could wear were torn out, worn out sneakers.
“I’m on my feet most of the time. I need protective foot wear,” Tomasini told Ivanhoe.
The surgery he is having will be painful, but Paul won’t feel a thing because he is being given a nerve block. “I like to compare it to an injection a dentist gives you before you have a cavity filled,” Edward Mariano, M.D., director or regional anesthesia at University of California San Diego, told Ivanhoe.
The anesthesiologist first uses ultra sound to locate the peripheral nerve near the surgical site.
Through a catheter, a nerve numbing medication is injected into the area, and minutes later the patient undergoes surgery without general anesthesia.
“You can breath on your own; you don’t require a breathing tube like you do with general anesthesia and after surgery your pain relief is very specific to the sight,” Dr. Mariano said.
Patients can stay awake for their surgery. In Paul's case, he caught up on some rest! He was home within a few hours. A small pump was attached to his catheter, giving him the control to add more or less pain medication directly to his foot.
“If I needed an extra dose of medicine, I would just pump this blue button," Tomasini said.
"What this allows patients to do is enjoy a better recovery in terms of having less mental confusion, less nausea, less itching," Dr. Mariano said.
The very next day, Paul was up and around ready to get back to work.
BACKGROUND: Nerve blocks involve the injection of a local anesthetic into or near a peripheral nerve or local pain-sensitive trigger point. Nerve blocks relieve pain by interrupting the body’s pain sensory pathways and preventing chemical signals indicating pain from reaching the brain. They are a convenient way to numb targeted areas of the body for specific surgeries, and are thus the ideal anesthetic for surgeries on extremities such as the legs and arms.
HOW IT WORKS: Using ultrasound, doctors can identify the location of the nerves. Once the anesthetic is injected around the nerves, the limb becomes progressively numb. They can be given in a single injection, a continuous infusion, or used to completely destroy the nerve for more permanent pain relief. A single injection can last several hours or up to one day. Unlike general anesthesia, patients receiving a nerve block can breathe on their own with no additional support. Patients do not experience nausea, vomiting, or sore throat. Patients recover more quickly and require less pain medication after surgery. Nerve blocks also provide effective anesthesia and pain relief for joint replacement surgery, major orthopedic trauma, severe burns, hernia repair, breast surgery, removal of kidney stones, and vascular surgery.
CAVEATS: Nerve blocks can provide temporary pain control but they are just one component of a pain management program. There can be side effects, such as allergic reactions to the local anesthetics. If steroids are used with the anesthetics to reduce inflammation, they can cause fluid retention, fluctuations in blood pressure and blood sugar, and mood swings. If nervous tissue is destroyed, a patient can experience partial loss of motor or sensory functions in the affected area. And patients who are taking anticoagulants such as heparin should not have a nerve block as the medications used can increase the risk of bleeding.
HOW ULTRASOUND WORKS: Ultrasound is a medical imaging technique that uses high-frequency sound waves and their echoes. It is similar to how bats navigate in the dark, and the SONAR used by submarines underwater. The machine transmits high-frequency sound pulses into the body using a probe. The sound waves travel through the body and bounce off any boundaries, such as between fluid and soft tissue, tissue and bone. Some of the sound waves are reflected back to the probe, while others travel further through until they bounce off another boundary. All the reflected waves are recorded by the machine, which then calculates the distance each sound wave traveled based on how long it took the sound wave’s echo to return. This data is used to form a two-dimensional image based on the distances and intensities of those echoes.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.