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Explore This IssueNovember 2006
TORONTO-Despite the evolution of endoscopic sinus surgery and a growing understanding of the pathophysiologic mechanisms of chronic rhinosinusitis (CRS), it remains a prevalent health care problem, afflicting approximately 30 million Americans.
To discuss some of the most recent advances and information in the evaluation and treatment of CRS, several noted experts in the field gathered to share their expertise and compare notes at the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) annual meeting.
Evaluating the Patient
When we look at patients with chronic rhinosinusitis, we really need to understand that the etiology may be multifactorial, said Pete S. Batra, MD, of the Cleveland Clinic. Certainly, surgery may play a role, but there are many other potential causative factors that we need to think about-immunodeficiency, for example.
Dr. Batra cited a study from the University of Iowa, in which researchers looked at their hard core population-patients who had undergone at least three previous surgeries. They found that 40% of those patients were anergic to delayed hypersensitivity tests, with 18% having low IgG levels and 16.7 % having low IgA levels.
Most interesting in that study is that almost 10 percent of them were diagnosed with common variable immunodeficiency and 6.2 percent had selective IgA deficiency-an incidence much higher than would be expected in the general population.
So if you’re going to work this up, you should think about getting quantitative immunoglobulins and also IgG subclasses, Dr. Batra said. You need vaccination and antibody responses to protein and polysaccharide antigens, and HIV if clinically indicated. If this is a workup you don’t feel comfortable performing yourself, it’s perfectly appropriate to recruit an immunologist. And that’s going to be especially critical if you’re going to consider any kind of immunoglobulin infusions.
Then there’s primary ciliary dyskinesia (PCD) to think about, Dr. Batra continued. These patients will universally have sinusitis and most of them will have recurrent otitis as well, he said. You’ll see bronchiectasis in about 83 percent and half of them will have the classic finding of situs inversus.
However, if you’re going to think about PCD, he advised, you have to recruit a pathologist with some interest and some experience in this who can work it up for you.
What I do is have them come to the clinic and do the brushing with a bronchoscopy brush, Dr. Batra said. We’ll brush the middle turbinate and then give them the specimen, which they’ll take directly to the lab where they can do dynamic studies.
Cystic fibrosis, Dr. Batra said, although it may be a soft indication, is certainly something to consider as well when evaluating CRS patients.
A study out of France from a couple of years ago looked at 44 patients with atypical chronic sinusitis. In these patients, at least one CFTR [cystic fibrosis transmembrane regulator] mutation was noted in 38 percent and one out of six had a positive sweat chloride test, he noted. So, you should consider CF testing in children with nasal polyposis and adults with a history of chronic rhinosinusitis that has been present all their lives.
When evaluating the CRS patient, Dr. Batra said it’s also important to think about asthma, which is a very common problem in this population.
You need to make sure they are on an appropriate regimen of inhaled steroids, leukotriene modifiers, and they should always have an rescue inhaler, he said. If you don’t want to manage their asthma, make sure they have a pulmonologist who is actively involved in their care. And think about chronic steroid use; many of these patients have been on steroids for years, so you should obtain a bone density study and make sure the patients are taking calcium and vitamin D. That’s a critical issue.
The bottom line, according to Dr. Batra, is that the effective evaluation and treatment of CRS truly requires a multidisciplinary approach.
We can drive it as otolaryngologists, but we need to incorporate other specialists into the mix when appropriately indicated, he said.
Is rhinosinusitis an infectious disease? That was the question posed by Peter H. Hwang, MD, of the Stanford Sinus Center at the Stanford University School of Medicine, who discussed cultures and the issue of identification of pathogens.
Clearly, we’re aware of inflammatory issues in chronic sinusitis; however, I think the infectious issues are still srelevant, but the relationship between these two is not clear, Dr. Hwang said.
The role of antimicrobial therapy is being reassessed, he said, citing a recent survey of the membership of the American Rhinologic Society.
It was almost unanimous that antibiotic therapy was considered to be part of maximal medical therapy in the treatment of chronic rhinosinusitis, Dr. Hwang said. So, if we do choose to use antimicrobial therapy for treating rhinosinusitis, then knowledge about the pathogen and its resistance profile is certainly relevant and it influences antimicrobial choices.
That highlights the importance of obtaining cultures, he said, noting that there are a number of technical factors that can influence success rate in obtaining a yield for traditional bacterial and fungal culture.
We can categorize those factors broadly as sampling technique and processing technique, Dr. Hwang said. In terms of sampling, there are a number of ways to obtain samples from the nose. You can swab the nose, you can irrigate, you can suction or you can puncture and aspirate.
Probably the most common ways of obtaining cultures in the office are either a swab or an aspiration, and studies have shown that the two techniques are basically equivalent in their yield.
Some of the more recent fungal data has used irrigation to harvest nasal mucin and to evaluate that microbiologically, Dr. Hwang said. Indeed, if you irrigate the nose, you can obtain a higher yield than swabs. But you need to consider the fact that this is non-localized sampling, so you’re sampling the entire nasal cavity when you might be interested in a more specific anatomic site, which may be better achieved by swabbing.
Another issue in sampling is that of contamination. We’re all aware that the nasal vestibule harbors different bacteria than the nasal cavity and can contaminate our specimens, he said. There have been some proposed modifications of technique in order to minimize contamination-either to sterilely prep the nasal vestibule or to use the tip of the nasal endoscope to lateralize the ala, which minimizes the contact between the swab or the suction tip and the nasal vestibule.
Moving from sampling to processing, Dr. Hwang said there are some processing issues to consider once the specimen has been harvested.
First of all, the type of cultured media matters. In addition, how the media is prepared for culture does matter, he said. The Mayo group showed that they could obtain a much higher yield on their fungal cultures when they applied a mucolytic technique prior to plating their nasal mucin. They were able to achieve up to a 96 percent yield.
Transport time to the lab is also significant processing factor that might affect the yield, Dr. Hwang pointed out, particularly if cultures sit out for a long period of time before they’re actually plated and processed.
Innovations in Pathogen Identification
While polymerase chain reaction (PCR) has moved from bench to bedside, it’s not widely available in terms of routine bacterial identification.
We do, however, have quite a bit of research that shows that we can use PCR as a very sensitive tool for the identification of both bacteria and fungi, Dr. Hwang said. By going directly to the genetic material, we can avoid many of the technical errors that may be associated with culture technique, and it has been shown to be highly sensitive.
Although it hasn’t reached the clinical realm yet, another promising innovation is that of the electronic nose-a technology that has mostly been used in industry.
It’s not really an olfactory device, but a chemosensory array that will electronically detect the volatile aspects of pathogens, Dr. Hwang said. What it can do, for example, is analyze the breath of a patient and detect bacterial sinusitis with fairly good accuracy. It has also been shown to be very sensitive in detecting tuberculosis in culture plates.
Another innovation on the way involves emerging data on the role of biofilms and chronic sinusitis.
It’s clear that some strains of bacteria have a tendency to form biofilms and others don’t, Dr. Hwang said. Data from a recent study showed biofilm forming strains of pseudomonas and staph may be associated with worse outcomes after FESS [functional endoscopic sinus surgery]. So, if we do have the ability to develop a clinically useful biofilm assay, this may be helpful in terms of managing our patients.
Maxillary and Frontal Disease
When addressing recalcitrant maxillary disease, recirculation is probably the most common cause for failed surgery in the maxillary sinus. Canine fossa puncture (CFP) has become the procedure of choice for many in clearing the maxillary sinus of disease.
Canine fossa puncture allows you to access all areas of the maxillary sinus, said Peter John Wormald, MD, of Queen Elizabeth Hospital in Adelaide, South Australia.
But, he noted, there can be a significant risk of postoperative morbidity associated with CFP, with nerve damage being a common side effect.
When you go through the canine fossa, the most common nerve you’re going to injure is the anterior-superior alveolar nerve (ASAN), which traverses the canine fossa in a vast proportion of patients, Dr. Wormald said.
To address this, Dr. Wormald and his colleagues began to look for an alternative landmark for performing CFP.
What we did is take a vertical line through the mid-pupillary line and a horizontal line through the ala, he said. If you perform your CFP at that point, then you are much less likely to injure the nerves. Now, this is a lot further lateral than the standard canine fossa. It’s at least a centimeter further.
Using this new landmark, Dr. Wormald said they were able to significantly reduce the incidence of postoperative morbidity.
We showed that we were able to reduce the incidence of complications using the new landmarks from 75 percent to 45 percent and were able to reduce the rate of persistent complications from 16 percent to 2 percent, he said. So, going that centimeter or so more laterally with your canine fossa trephine, you can avoid significant damage to the anterior-superior alveolar nerves.
When evaluating and managing the patient with frontal disease, on the other hand, establishing a functional outflow tract is critically important, according to Martin J. Citardi, MD, of the Cleveland Clinic.
The other important concept is that the frontal sinus problem is very rarely, if ever, in the frontal sinus, he said. In fact, you could almost argue that the problem is never in the frontal sinus; it’s always in the frontal recess.
The big issue, Dr. Citardi noted, is understanding the anatomy and using that understanding to employ the right combination of procedures before choosing a surgical approach.
Having good imaging is critical in putting together the comprehensive treatment, and that imaging includes high-resolution CT and MRI in selected cases, he said. Then, at the time of surgery, you need to execute on the plan, and in the postoperative period, you’re committing the patient to perioperative management to promote wound healing and maintain frontal recess and frontal ostial patency.
Although the frontal sinus is similar in many ways to the maxillary sinus, in that it is primarily a surgical problem, the anatomy is so complex and there are so many different procedures that have been proposed over the years, Dr. Citardi said there are a lot of factors that go into the imaging and evaluation of these patients.
When we talk about frontal sinus disease, we have to remember that sinusitis overall is primarily a medical disease, he said. The overall principles of the management of sinusitis also apply to the management of frontal sinusitis.
©2006 The Triological Society