Nerve mapping technology improves surgery for compressed nerves

March 22, 2013

Nerve mapping technology allows surgeons to determine whether surgery has been effective for relieving pressure from compressed nerves, which often function poorly and cause sciatica or pain and weakness in muscles supplied by the nerve.

In a small study involving 42 patients at Henry Ford Hospital, lead author and Stephen Bartol, M.D., says that mechanomyography, or MMG, is effective with measuring and determining whether nerves are compressed.

MMG, which functions by detecting muscle movement and sending real-time alerts to surgeons, measures the performance of nerves during surgery, thereby reducing the risk of inadequate surgery and eliminating the need for additional surgery.

While encouraged by his findings, Dr. Bartol urged caution that more research is needed involving larger patient populations.

"Traditionally, when we operated on someone who has nerve decompression, we didn't know if we had done enough during the surgery at the time. It was basically wait and see after the patient recovered," Dr. Bartol says. "With the MMG tool we can differentiate between normal and compressed nerves, and gauge the severity of the compression."

The study is being presented Friday at the American Academy of Orthoapedic Surgeons' annual meeting in Chicago.

It is estimated that back pain will affect eight of 10 people in their lifetime, and one-quarter of U.S. adults report having lasting at least one day in the past three months.

With the rise in minimally , physicians are craving the need for an effective tool to monitor nerve function during surgery.

Conventionally, surgeons assess nerve decompression using direct visualization or a probe called a Woodson elevator, methods Dr. Bartol describes as "purely subjective" and prone to error. Another method , or EMG, which monitors the electrical response of muscle, is unreliable because electrical noise in the operating room makes it difficult to quantify nerve responses, Dr. Bartol says.

MMG, Dr. Bartol says, monitors the same physiological effects as EMG but uses smart mechanical sensors that are not susceptible to electrical interference. He says clear signals of can be detected at low electrical current thresholds.

In the study, researchers sought to test the electrical threshold of stimulation of 64 nerves in 41 patients by direct contact prior to and after decompression, during which a small portion of bone over the nerve root is removed, enabling the nerve root to heal without hindrance.

Stimulation started at 1mA electrical current and gradually increased until an MMG response was achieved.

The findings:

  • Prior to decompression, 89 percent of nerves had an elevated median threshold of 4.89mA.
  • After decompression, nerves had a median threshold of 2.08mA and 70 percent had normal threshold of 1mA.
  • After decompression, all 64 nerves had measurable increases in MMG response.
  • After decompression, 98 percent of nerves with abnormal pre-compression values had a drop in threshold greater than 1mA.

Dr. Bartol says these findings show that MMG technology "allows the surgeon to make better decisions in the operating room. Inadequate means patients will continue to experience pain after surgery. Better testing during surgery should translate to better outcomes."

Explore further: Chronic migraine headache relief possible with outpatient surgery

Related Stories

Chronic migraine headache relief possible with outpatient surgery

January 4, 2013
When medications fail to eradicate debilitating migraine headaches, surgery could provide relief for certain patients.

JAAOS study highlights success of nerve transfer surgery

August 1, 2012
Because many physicians are unaware of nerve transfer surgery, some patients suffer long-term impairment from nerve injuries that could have been fixed.

Improved method of electrical stimulation could help treat damaged nerves

November 21, 2011
Functional electrical stimulation (FES) was developed to help return lost function to patients with upper and lower extremity injuries and spinal cord injuries, among other applications. However, the devices, which work by ...

Nerve sparing helps most prostate cancer patients to have same orgasms as before surgery

February 13, 2012
The vast majority of men who have a prostate cancer operation can retain their ability to orgasm if the surgery is carried out without removing the nerves that surround the prostate gland like a hammock, according to a study ...

Study finds long nerve grafts restore function in patients with brachial plexus injury

March 22, 2013
A study by researchers at Hospital for Special Surgery (HSS) challenges a widely held belief that long nerve grafts do poorly in adults with an axillary nerve injury. Investigators found that the outcomes of long nerve grafts ...

Recommended for you

Study finds harmful protein on acid triggers a life-threatening disease

July 27, 2017
Using an array of modern biochemical and structural biology techniques, researchers from Boston University School of Medicine (BUSM) have begun to unravel the mystery of how acidity influences a small protein called serum ...

CRISPR sheds light on rare pediatric bone marrow failure syndrome

July 27, 2017
Using the gene editing technology CRISPR, scientists have shed light on a rare, sometimes fatal syndrome that causes children to gradually lose the ability to manufacture vital blood cells.

Post-stroke patients reach terra firma with new exosuit technology

July 26, 2017
Upright walking on two legs is a defining trait in humans, enabling them to move very efficiently throughout their environment. This can all change in the blink of an eye when a stroke occurs. In about 80% of patients post-stroke, ...

Molecular hitchhiker on human protein signals tumors to self-destruct

July 24, 2017
Powerful molecules can hitch rides on a plentiful human protein and signal tumors to self-destruct, a team of Vanderbilt University engineers found.

Researchers develop new method to generate human antibodies

July 24, 2017
An international team of scientists has developed a method to rapidly produce specific human antibodies in the laboratory. The technique, which will be described in a paper to be published July 24 in The Journal of Experimental ...

New vaccine production could improve flu shot accuracy

July 24, 2017
A new way of producing the seasonal flu vaccine could speed up the process and provide better protection against infection.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.