New methods show success in helping people ease pain

MEDICAL MATTERS

Medicine & Science

November 24, 2003|By Judy Foreman | Judy Foreman,SPECIAL TO THE SUN

Dr. Darlyne Johnson, 46, an obstetrician-gynecologist at South Shore Hospital in S. Weymouth, Mass., is no stranger to pain - and not just the pain of other women having babies.

Over the years, Johnson has had several surgeries, and each time, wound up with such terrible nausea and vomiting from painkillers that she had to stay in the hospital overnight.

Not surprisingly, when she found out three years ago that she needed hernia surgery, she balked. Then she heard about a device called ON-Q. It consists of a tiny tube, placed in the incision and connected to a small container of local anesthetic worn outside the body.

Like water through a soaker hose, the medication, usually lidocaine, oozes into the wound for several days. The idea is that by blocking pain at the site of injury, patients should need smaller doses of opioid painkillers, which act on the whole body and often make people feel sick and dazed.

"Basically, I was pain-free," says Johnson, who began offering ON-Q to patients undergoing Cesarean sections.

And that is just the beginning of doctors' increasingly successful efforts to manage pain.

Chronic pain, which can be caused by damage to nerves (as in shingles or diabetes), inflammation (as in arthritis) and diseases (such as cancer), is a fact of life for 50 million Americans, according to some estimates. An additional 25 million suffer every year from acute pain after surgery or injury.

While pain is subjective, there is growing evidence of how pain is registered in the brain.

In one recent report, Wake Forest University School of Medicine researchers subjected volunteers to pain (heat) on their skin and had them rate it. They also scanned the subjects' brains with functional magnetic resonance imaging (fMRI) and found that in those reporting the most intense pain, several regions of the outer layer of the brain were activated more often and more intensely.

Dr. Catherine Bushnell, an anesthesiologist at McGill University, found that when people are distracted from pain, the scans reflect a dampened experience of pain.

This growing understanding of pain is changing the way it is treated, says Dr. James Rathmell, an anesthesiologist at the University of Vermont Medical College in Burlington.

One example is sensitization, or "wind up" pain. When you injure nerves in your finger, nerves in the spinal cord reorganize to amplify pain and remember it. In other words, acute pain becomes transformed into chronic pain.

To prevent this in surgical patients, some doctors give patients COX-2 inhibitors such as Vioxx or Celebrex before surgery. These drugs block an enzyme called cyclooxygenase-2, a key player in pain transmission.

For women in labor, low doses of morphine injected into the intrathecal space around the spinal cord provide "tremendous pain relief," Rathmell says.

For cancer pain, doctors implant a permanent catheter (a tiny tube) into the intrathecal space and attach the tube to a morphine pump placed in the abdomen. A Johns Hopkins study showed that this technique not only provides drastic pain relief, but also increased longevity by a month or two.

Non-drug approaches to pain control, most notably acupuncture, also can be effective for some kinds of pain.

As for ON-Q? One study found it had no effect after knee surgery. But the company that makes ON-Q, I-Flow Corp., says studies of patients undergoing hysterectomies or colorectal surgery found that many required less than the usual level of opioids after surgery.

At the Johns Hopkins Hospital, anesthesiologists Dr. Lee Fleisher and Dr. Christopher Wu are studying ON-Q in prostate surgery patients. "We are very interested in seeing if there is a benefit to blocking pain up front and never getting `wind up' pain," says Fleisher.

Judy Foreman is a lecturer on medicine at Harvard Medical School. Her column appears every other week. Columns are available on www.myhealthsense.com.

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