Real-Time 3D Ultrasound Imaging Speeds up Patient Recovery Times

In this way, they can rapidly block nerve function in selected areas of the body before surgery, a development that may spare patients from use of general anesthesia and sends the infants home faster and with less need for pain medication.

Anesthesiologists from the Mayo Clinic division in Jacksonville, FL, USA, have demonstrated the benefits of real-time 3D ultrasound in nerve blockade in more than 150 surgeries of varied types. Their research has informed other physicians worldwide into how this innovative ultrasound imaging technology may aid in peripheral nerve block placement--the technique of disabling targeted nerves so that a patient doesn't feel pain from surgery.

For example, their latest case study, reported in the July 2007 issue of the journal Anesthesia & Analgesia, describes how they used 3D ultrasound to find the sciatic nerve behind the thigh of a woman who needed major reconstructive surgery on her foot. Utilizing the imaging technique to help physicians place a catheter filled with local anesthetic next to the nerve, they numbed it to block pain signals from being transmitted to the brain of the patient, who was sedated.

When the brain does not know surgery is under way because the nerve is inactivated, it does not initiate the kind of systematic pain response that keeps patients medicated and in their beds, according to anesthesiologist Steven Clendenen, M.D., who helped develop use of the technique with Neil Feinglass, M.D., and other anesthesiologists at Mayo Clinic in Jacksonville.

Most people are familiar with traditional 3D ultrasound probes that can see a growing fetus and an adult's beating adult heart using waves that penetrate deep within body tissue and reflect back to form an image. But these devices cannot be used to image nerves, because nerves are often too close to the surface of the skin and too shallow for the sound waves generated to form an image.

Dr. Feinglass, who specializes in cardiac anesthesiology, and Dr. Clendenen, a specialist on regional pain blocks, thought of using smaller ultrasonic probes to image nerves. "We thought nerves could be very ultrasound friendly because they run in a linear plane and are wrapped in a sheath of fat, so they easily reflect back ultrasound waves,” remarked Dr. Clendenen.

The clinicians evaluated two different Philips Medical Systems (Best, The Netherlands) transducers known as the x3-1 and x7-2 Matrix array transducers. The x7-2 Matrix array had been recently designed to image the tiny hearts of infants. Both provide sharp resolutions even at shallow depths, according to Dr. Clendenen.

The clinicians have used this technique to place blocks on nerves in the neck, under arms, below collarbones, and in the backside upper portion of legs.


Related Links:
Mayo Clinic
Philips Medical Systems