Wednesday, April 28, 2004

Harmonic scalpel reduces blood loss, operative time for tumors of saliva gland

A tool known as the harmonic scalpel removes tumors of the saliva glands as effectively as cold knife dissection.

Dr. Christine Gourin, a head and neck surgeon in the Department of Otolaryngology at MCG Health System, is the first in the state to use the technique to remove tumors of the parotid gland. The triangular-shaped gland is the largest of the saliva glands, with one located in front of each ear.

“It’s a tricky procedure,” said Dr. Gourin, who has co-authored a study on the effectiveness of the scalpel. “Because the facial nerve runs through the parotid gland, nerve damage and facial paralysis is a risk of surgery. But we’ve found that the harmonic scalpel is just as safe as conventional methods and results in less blood loss and greatly reduced operative time for the patient. In fact, because less blood is lost, the facial nerve may be even easier to identify during surgery.”

The harmonic scalpel is uniquely suited to surgeries where protection of nerve function is important. Ultrasonic vibrations are produced by the expansion and contraction of piezoelectric crystals housed in the hand piece of the scalpel and transferred to the blade through blade extenders. The scalpel vibrates at a frequency of 55,000 Hz and cuts tissue bonds at temperatures in the range of 60 to 80 degrees Celsius. It simultaneously cuts and coagulates, with low resulting thermal transduction and no electric current.

JW Little of Augusta underwent a parotidectomy (removal of the parotid gland) in September 2003. Little’s parotid tumor had grown slowly over a matter of months, until it was the size of an egg. Sore to the touch, it also began to bother him during eating and hindered him from sleeping on his side. “At first, I didn't pay it any mind,” he said. “But when it got bigger, my wife, Deborah, and I decided we needed to have it checked out.”

A needle biopsy and MRI were non-diagnostic, but Gourin recommended removal of the gland. “Most lumps of the parotid gland are benign, but the danger is that they can undergo malignant transformation,” said Gourin. “In addition, the needle biopsy is effective mainly in confirming cancerous tumors, not those that are benign. Most experts continue to recommend removal of the gland when tumors are found to be present.”

During conventional cold knife dissection of the parotid gland, bipolar electrocautery would be used to close bleeding vessels, increasing risk of thermal and electrical injury to the facial nerve. During Little's parotidectomy, Gourin used the harmonic scalpel to cleave the parotid gland, exposing and identifying the facial nerve and peripheral nerve branches, and coagulating blood vessels throughout the procedure. Following careful removal of the gland, a drain was placed and the incision was closed.

All told, Little’s surgery and recovery took only three weeks, far less time than it did for the tumor to develop. The rapid recovery was a welcome surprise to both Little and his wife. A diabetic, Little had a kidney transplant in 1988 and remembered the lengthy healing process. While this surgery was much smaller in scope, still, he said, “It was amazing to me that a diabetic could heal that quickly.”

A later examination of the tumor found that it was indeed cancerous. “Today, I’m very happy,” said Little of the procedure.

“The harmonic scalpel has been used for other head and neck procedures such as thyroidectomy [thyroid removal], but this is the first time it’s been used to remove these types of cancers,” said Gourin. “As a specialist in head and neck cancers, I’m very pleased to find a new application for this tool and look forward to seeing other applications developed for it in the treatment of cancer.”