"We think we are resetting the thermostat in women who are experiencing moderate to very severe hot flashes without using hormonal therapies," said David Walega, MD, chief of the Division of Pain Medicine at Northwestern Memorial Hospital andNorthwestern University Feinberg School of Medicine. Walega presented the results of the initial study at a recent American Society of Anesthesiologists annual meeting.
Forty women between 35 and 65 years old experiencing natural or induced menopause participated in the study. The women suffered debilitating hot flashes with more severe symptoms than the typical hot flash.
"Many of the women in our study experienced repeated drenching sweats that lessen the ability to go about a day-to-day routine, including interfering with their professional lives," said Walega. " We wanted to see if this injection could provide symptom relief without hormones, as hormone therapy has been associated with an increased risk of cancer, stroke and heart disease, and there are few other viable treatment options available right now."
To administer the treatment, the doctor used low dose X-ray to guide an injection of bupivacaine hydrochloride, a commonly used local anesthetic, into a nerve bundle called the stellate ganglion, located in the neck near the "voice box." It's a 30 second procedure that must be done by a trained physician because the injection is close to important structures like the carotid artery, the vertebral artery and the spinal nerves. Injecting any of those areas could cause a seizure, loss of consciousness or other complications.
The idea came from a pain study published in 2007 in the medical journal "The Lancet," where stellate ganglion injections were performed to try to alleviate pain. In some cases, hot flashes dissipated after the injection, independent of pain relief, leading Walega's research team to wonder if this might be a safe, effective way of treating hot flashes from menopause.
Walega's patients tracked their hot flashes for two weeks before and six months after the injection. Half the group got the anesthetic; the other a placebo injection of saline, or salt-water. Those who received the anesthetic medication reported a reduction of hot flashes by a half. The benefits lasted at least six months.
Walega is now planning a larger study to further investigate the shot's effectiveness.