Right Recurrent Laryngeal Nerve Shows Greater Stimulation in Spine Surgery; May Indicate Greater Risk

Similarly, in 2007 (Terris et al. Arch Otolaryngol Head Neck Surg 2007;133:1254-7), researchers found that, in 137 patients undergoing minimally invasive thyroid surgery, there was a 4.3% rate of temporary paresis in the group that was monitored and a 6.0% rate in those who were not monitored.

While neither of these groups showed a statistically significant difference between monitored and unmonitored groups, both authors still support the use of it, giving them additional monitoring during their surgeries, Dr. Bellapianta said. Recurrent laryngeal nerve injuries can cause significant voice dysfunction and morbidity if they occur during the anterior cervical spine surgery. And thus I feel it does warrant figuring out ways to make this a safer surgery.

After the presentation, an audience member said that another study found that the rate of injury is more related to the endotracheal tube’s cuff pressure than stretching, the main problem being the pinching of the soft tissue where the nerve lies between the cuff and the retractor blade. He said that the researchers have been reducing the pressures to the minimum needed, and their rate of paralysis has virtually disappeared.

Dr. Bellapianta agreed that there is still no clear answer. A follow-up study, she said, found that patients for whom cuff pressure was reduced fared no better than those for whom the pressure was not reduced (Audu et al. Anesthesiology 2006;105:898- 901). They concluded that perhaps cuff pressure, deflating it or regulating it, doesn’t make a difference, she said. So it still is controversial as to what exactly is causing it.

Marvin Fried, Chair of the Department of Otorhinolaryngology at Montefiore Medical Center and the current President of American Laryngological Association, said he was struck mainly by the small number of patients in the Albany study.

I believe it is too early to make conclusions based on this study, Dr. Fried said. As with many similar endeavors, more patients are needed.

Dr. Bellapianta acknowledged that was a limitation of the study. She also said that a deficiency in this area of research is that most studies have been retrospective. No study, she said, has actually looked specifically at left versus right in a prospective manner.

©2009 The Triological Society