Experts Debate Pediatric Airway Issues

In a recent debate-style panel, five otolaryngologists addressed topical clinical issues relating to the pediatric airway ranging from adenotonsillectomy in children with obstructive sleep symptoms, to whether cidofovir should be used as a standard treatment in children with recurrent respiratory papillomas. Charles Myer, III, MD, Professor of Pediatric Otolaryngology-Head and Neck Surgery at Cincinnati Children’s Hospital, moderated the session. Participants also spoke with ENT Today after the panel discussion.

There are different camps on the issues raised in the debate, and I wanted to stimulate discussion, Dr. Meyer told ENT Today. Because of the stylized debate format of the session, the opinions the speakers expressed were not necessarily indicative of what they do in individual practice. But the opinions expressed during the debate do reflect sides of the issue seen in pediatric otolaryngology practice as a whole-making them pertinent issues to ponder.

Resolved: It is below the standard of care to perform adenotonsillectomy in children with obstructive sleep apnea symptoms without a sleep study.

Pro: Amelia Drake, MD, Professor of Otolaryngology-Head and Neck Surgery, University of North Carolina School of Medicine.

Dr. Drake discussed four potential reasons that it is below the standard of care not to have a sleep study prior to adenotonsillectomy. For one, some research suggests that many children (especially if they are obese) do not have complete improvement when their tonsils are taken out. For instance, a study from the University of Louisville demonstrated that some children do not return to a normal apnea-hypopnea index (AHI) in their postoperative sleep studies. Postoperatively, the study showed that 25% of the study participants had a normal AHI, but 35% had an AHI between 1 and 5, and 29% had an AHI greater than 5. Children who were obese had the greatest risk of not returning to normal.

A second reason is that obstructive sleep apnea may be a potential cause of attention deficit hyperactivity disorder (ADHD), an area of increasing study in various areas of pediatrics. Some studies in the medical literature suggest that there is a higher incidence of ADHD in children who are found to have abnormal sleep studies. A study from the University Michigan, which Dr. Drake noted was fairly representative, found that children who have abnormal sleep studies and go on to have adenotonsillectomy have a higher incidence of ADHD.

Then there is the risk of the operation. A University of Minnesota study showed that patients who had significant abnormalities in preoperative sleep studies had significant postoperative respiratory compromise. In fact, in the study, a small number of children stayed one to 30 days postop with respiratory failure and other problems. Researchers identified associated medical problems. Children with conditions such as craniofacial anomalies, hypertonia, morbid obesity, previous airway trauma, or cor pulmonale would benefit from sleep studies to evaluate their risk, she said.

This shows that sleep studies are a useful tool for helping predict risk.

She noted that in the UK, there is a practical and commonsense approach to the sleep study. Patients are triaged according to their level of risk into high, moderate, or low risk, and procedures are scheduled according to how severe is their risk of having perioperative complications. High-risk groups would go to a pediatric specialty center with an ICU; moderate risk would have availability for CPAP [continuous positive airway pressure]; and low risk could be operated on at a local general hospital, she said.

A fourth reason is that primary snoring alone may represent a risk. How would we know that unless we have done sleep studies to see if primary snorers were primarily snorers or if they had severe obstructive sleep apnea? she said.

Con: Robert Yellon, MD, Professor of Otolaryngology, University of Pittsburgh School of Medicine.

Guidelines from both the American Academy of Pediatrics and the American Thoracic Society suggest that polysomnography (PSG) is the gold standard for diagnosis of primary snoring versus obstructive sleep apnea syndrome. But the question that comes up is: Is PSG always required to document OSA prior to T&A [tonsillectomy and adenoidectomy]? he said. Also, does primary snoring require adenotonsillectomy?

Although some studies in the medical literature suggest that PSG is superior to clinical evaluation in distinguishing OSA from primary snoring, the quality of those studies varies, he said. In addition, there is a lack of standardization, making it difficult to have a good definition of what constitutes a normal versus an abnormal study.

Some labs use a nasal flow thermistor, and others use a nasal pressure sensor, which is more sensitive to detect hypopneas. You’ll find a higher obstructive index using the pressure sensor. And a child may have OSA but you may make a diagnosis of primary snoring if you just use a thermistor, he said.

Additionally, there are variations in the definition of hypopnea. Some labs would say a 50 percent reduction in airflow with 4 percent reduction in oxygen saturation; and others would say only a 30 percent reduction of airflow with a 4 percent reduction in oxygen saturation. Other labs do not measure end tidal CO2, and some do; this is essential to confirm or exclude hypoventilation. And some labs do not differentiate between central versus obstructive apneas; they just report an apnea index, Dr. Yellon said. What would be considered normal at one center could be abnormal in another.

A common argument supporting the use of PSG is that clinical evaluation alone is poor at distinguishing OSA from primary snoring. However, one meta-analysis of PSG studies found that 11 out of 12 (studies) concluded that a clinical evaluation was poor at distinguishing the two entities; however, four of the 11 used adult criteria of more than five respiratory events an hour. In one study, the criteria were not specified, and in another there was no control group. These studies may underestimate the incidence of symptomatic OSA, he said.

Dr. Yellon cited several studies that showed that both children with OSA and those with primary snoring experience improvements after undergoing adenotonsillectomy. If both benefit, then PSG is not really needed. Indeed, primary snoring and upper airway resistance syndrome without OSA appear to be detrimental to health. And adenotonsillectomy results in significant improvements for quality of life, he said.

Some in the field argue that a preop PSG can diagnose and quantify OSA and be used to predict postop morbidity. This can be countered by the fact that postoperative monitoring can identify patients at risk for respiratory complications, which is demonstrated in some studies, he said. But some groups of children do need a PSG, such as children under three years of age who have severe preoperative respiratory disturbances.

History and physical exam is the initial step to establish the diagnosis of sleep-disordered breathing. If the child has snoring, gasping, struggling to breathe, and pauses, and daytime fatigue, attention deficit disorder, hyperactivity, emotional lability, and poor weight gain, or at least some or most of these criteria and you see enlarged tonsils, you can proceed with a adenotonsillectomy, he said.

Resolved: Mandibular distraction is the standard of care for the management of airway obstruction in the neonate with retrognathia.

Pro: David Tunkel, MD, Associate Professor of Otolaryngology-Head and Neck Surgery and Pediatrics, Johns Hopkins University.

Retrognathia is an issue with which many pediatric otolaryngologists struggle. Children present with an evident defect, yet studies show that over time many cases resolve spontaneously. Dr. Tunkel noted that there is a wide variation in children, especially neonates, with upper airway obstruction from retrognathia. They differ in the size, shape, the position of the mandible and the tongue, and more.

They may have second airway lesions, systemic disease that affects the heart and lungs, may have feeding problems related or unrelated to the airway obstruction, and may have different clinical manifestations, he said. There is a variety of ways to evaluate these patients, including PSG and clinical monitoring, as well as various outcome measures.

Mandibular distraction is aimed at relieving airway obstruction caused by tongue base and supraglottic collapse, and in most cases internal devices are used for the distraction. The procedure is useful in children who have the Pierre-Robin triad, usually defined as retrognathia, glossoptosis, and respiratory distress-but sometimes cleft palate is substituted for respiratory distress.

Multiple retrospective studies and case series have shown both decannulation from, and avoidance of, tracheotomy, as well as improved feeding using manibular distraction, in children with the Pierre-Robin triad, he said.

Evidence shows that there are short-term benefits from treating the Pierre-Robin triad, as well as some good long- term data-but children need long-term follow-up, as a small number of patients may have persistent or recurrent sleep apnea, Dr. Tunkel said.

However, mandibular distraction is just one of several surgical procedures that can be used for the Pierre-Robin sequence and other neonates with retronagthia causing airway obstruction, he said. Generally, it is important to decide whether intervention is needed, and do a good assessment of the nature and severity airway obstruction.

Mandibular distraction is the most appropriate intervention for certain patients. It may be for the child who is having severe airway obstruction from tongue base obstruction as a neonate, where tracheotomy is really the only other option, he said.

Con: J. Paul Willging, MD, Professor of Otolaryngology, University of Cincinnati College of Medicine.

Whereas mandibular distractions are one tool to approach retrognathia, we have a lot of other options that we’re comfortable with utilizing, Dr. Willging said. Other options include different types of nipples and positioning the child differently. And, in children who essentially lack a chin, one can wait to see if the problem goes away over time as the child grows.

When deciding which approach to use, doctors need to consider various available procedures, their efficacy, associated costs, operative morbidity, and the overall risk-benefit ration of intervening versus not intervening.

He noted that mandibular distraction can be effective. It generates new bone, the cosmetic appearance of the child is improved, and the airway is cleared. However, devices are often both uncomfortable and unsightly. Sometimes there are device failures, and some children will need further surgical intervention.

Downsides include the fact that many distraction procedures lead to an open bite deformity. The procedure is also resource-intensive, with children needing prolonged time in the intensive care unit. It often takes multiple disciplines to watch these kids and manage them during their perioperative period, he said.

Various complications can occur, such as mandibular growth derangements or abnormal tooth growth resulting from pins that interfere with tooth bud development. Temporomandibular joint abnormalities, malunions, nonunions, malocclusions, and premature consolidations can be added to the list.

If we’re going to be doing mandibular distraction in infants we need to approach this in a scientific fashion, he said. Protocols need to be developed, and which patients qualify should be better defined. Children need near- and long-term follow-up, and outcomes need to be defined as well.

Resolved: Adjuvant therapy, especially cidofovir, should be standard treatment for children with recurrent respiratory papillomas (RRPs).

Pro: Robert Yellon, MD.

Cidofovir is a cytosine nucleotide analog that inhibits viral DNA polymerization. When the first pediatric report in 1999 showed that four of five children seemed to improve, a lot of enthusiasm was generated for use of the drug. Data suggest that cidofovir is fairly effective, although most studies are not of the highest quality design, being either retrospective or case studies.

One large review found that more than 91% of cases had some improvements with the drug, but noted that randomized trials are needed to better determine its efficacy, he said. One randomized, double-blinded, placebo-controlled trial determined that there was no proof of efficacy of cidofovir and that it was hard to tease out the natural history versus the effect of the drug, he said.

The drug is also associated with a risk for malignant transformation, and there are some reports of mammary adenocarcinoma occurring in rats, even with low doses. However, studies with monkeys and primates found no tumors.

Overall, there is insufficient evidence to prove the efficacy of cidofovir but there is the need for additional randomized prospective trials, Dr. Yellon said.

The current indications for cidofovir by the multidisciplinary RRP Task Force state that intralesional cidofovir should be used for moderate to severe disease requiring surgical treatment at least four times a year, aggressive disease with airway compromise, or severely impaired communication. However, informed consent discussing the nephrotoxicity and the carcinogenic potential of the drug should be required for these patients, and it should be written in the chart; and that all adverse responses should be reported to the task force, he said.

Con: David Tunkel, MD.

Dr. Tunkel agreed with the cautionary points made by Dr. Yellon about the drug. He concurred that nephrotoxicity was the biggest immediate concern, and noted there have also been case reports of patients with dysplasia. However, there’s a risk of spontaneous malignant degeneration of RRP without intralesional cidofovir [and] that malignant generation of RRP to squamous cell carcinoma may not involve progression through dysplasia.

From his own survey of the medical literature, he concluded that cidofovir appears to help RRP patients. However, the literature is varied and not completely convincing, with the most worrisome side effect being potential carcinogenesis.

Remember, it is an off-label use. You need to have a frank discussion with parents of patients about this. They tend to be pretty well informed because they come in with literature from patient support groups. I don’t think it’s yet for routine use; it’s for the severe patients, the patients who require multiple surgeries or the patients who have progression before your eyes, Dr. Tunkel said.

©2009 The Triological Society