Jul 6 2005
A few X-ray measurements can help determine whether chronic problems with the hard-to-reach frontal sinuses can be corrected with surgery, according to a new study.
"The frontal sinus is behind the forehead and it has a very tortuous drainage," says Dr. Stil E. Kountakis, vice chair of the Medical College of Georgia Department of Otolaryngology-Head and Neck Surgery. "It's the most difficult sinus to work with."
The good news is the frontal sinuses, which run parallel to the eyebrows, are not the most common site for infection. The bad news is the sinuses between the eyes - the ethmoids, into which the frontal sinuses drain - are, says Dr. Kountakis.
"The general recommendation is to avoid frontal sinus surgery as much as possible," he says, citing potential hazards that come with their proximity to the skull base and the orbits.
But when chronic symptoms such as headache, cough, sore throat, nasal congestion and drip don't respond to medical therapy, miserable patients may opt for surgery that effectively obliterates their frontal sinuses. Surgeons crack open the skull, open the frontal sinuses, remove the lining and fill the empty cavity with abdominal fat. "A better solution is to perform functional endoscopic surgery that provides a large area for the sinuses to drain while preserving sinus function," says Dr. Kountakis, who directs the Georgia Sinus and Allergy Center.
He is corresponding author on a study published in the May/June issue of the American Journal of Rhinology that should help surgeons determine if patients are instead candidates for a sinus-saving modified Lothrop procedure.
The procedure enables sinus surgeons to work through the nose to create a larger drainage pathway for the frontal sinuses by removing the floor of the sinuses between the eyes and creating a hole in the septum that separates the nose. "This opens up the sinuses so they drain without obstruction," says Dr. Kountakis. 'This is a last-ditch effort to try and fix chronically obstructed frontal sinuses.
"By doing the surgery over and over again, I've learned to look at the (computerized tomography) scan and check to see if I had room for my instruments to go through," says Dr. Kountakis, senior author of the recently released first textbook on the frontal sinuses.
He wondered if guidelines could be developed to help others do the same.
He and colleagues Dr. Ramon E. Figueroa, MCG neuroradiologist, and Dr. Firas T. Farhat, MCG sinus fellow who is now the first fellowship-trained rhinologist practicing in Lebanon, determined those measurements by studying the CT scans and anatomy of seven cadavers.
They identified the critical measurements as the thickness of the nasal beak, the boney structure between the eyes where the nose and forehead meet, as well as the "accessible dimension," a term Dr. Kountakis coined for available working space inside the frontal drainage area.
"Even with the smallest instruments that are available today, this dimension should be at least 5 mm (about .2 inches) to allow for safe drill insertion," the study authors write of the accessible dimension.
"The smaller it is, the harder it is," says Dr. Kountakis. "You need to have some space that will admit all these instruments going up into the forehead."
Researchers also measured the distance between the nasal beak and the front of the nearby skull base as well as the widest front-to-back depth of the frontal sinuses.
By their new measurements, four of the seven cadavers qualified for the sinus-saving modified Lothrop procedure. The researchers suggest long-term clinical studies to further assess the efficacy of the measurements.