PHOENIX-The right recurrent laryngeal nerve showed greater stimulation than the left during anterior cervical spine surgery on 40 patients, researchers have shown in a study intended to promote greater understanding and prevention of damage to the recurrent nerve during the procedure.
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September 2009Researchers at Albany Medical Center in New York said the findings indicate that the right recurrent laryngeal nerve might be at a higher risk of injury during the surgery.
They found one case of vocal fold paralysis among the 40 patients and no correlation between the electrical signaling and vocal fold injury, leaving the controversy over which side is best for the operation continuing to smolder.
The right recurrent laryngeal nerve does show greater stimulation during the surgery, said Karen Bellapianta, MD, who presented the findings at the 130th Annual Meeting of the American Laryngological Association, conducted as part of the Combined Otolaryngology Spring Meeting. It may be at increased risk, but it will take future study in order to prove this.
Cervical spine surgery is important to laryngologists because of the risk of injury. Monitoring electrical signals might give an early indication of a problem during the surgery, possibly helping to prevent injuries.
We, as otolaryngologists, care about anterior cervical spine surgery because the most common complication is temporary or permanent recurrent largyngeal nerve paralysis, or paresis, recorded in the literature, anywhere from 1 to 24 percent, Dr. Bellapianta said.
There is clear evidence that the right side is at greater risk of being stretched and, in our study, stimulated. However, this does not translate into a higher risk of being injured and that has yet to be proven.-Karen Bellapianta, MD
Which Side Is Safer? Controversy Continues
In Surgical Exposures in Orthopedics: The Anatomic Approach, Hoppenfeld and de Boer wrote that the recurrent laryngeal nerve is the most important structure at risk during the [anterior cervical] approach.
But which side is the best for performing the surgery is a question that has not been settled. There’s a lot of controversy in the literature about which side of the neck is safer to operate on, Dr. Bellapianta said.
The left recurrent laryngeal nerve is more consistent in its position. It loops around the aorta and is found in the tracheal esophageal groove, ascending along a direct vertical trajectory. The right recurrent laryngeal nerve is inconsistent in its position, entering from a more lateral position after looping around the subclavian artery.
Nerve Stimulation Studied
In the study, a nerve integrity monitor endotracheal silicone tube was used, with four stainless steel wires exposed about 30 mm above the cuff. They gave off a signal when the recurrent laryngeal nerve was stimulated.