Recently, our international, multicenter study examining drug-induced sleep endoscopy and surgery outcomes in those with obstructive sleep apnea but without markedly enlarged tonsils was published in the medical journal Laryngoscope. I have written on this blog about the research findings and the implications for sleep surgery and the decisions that sleep apnea surgeons make for their patients. One of the key findings was the association between oropharyngeal lateral-wall related obstruction and poorer outcomes. This article examines this finding in the context of a research study published this month.
Palate procedures based on tissue repositioning – like expansion sphincter pharyngoplasty or lateral pharyngoplasty – have demonstrated better results than traditional uvulopalatopharyngoplasty in randomized trials linked here and here. These techniques were developed to address the oropharyngeal lateral walls that can contribute to obstructive sleep apnea in many patients, and my personal experience is that this is true. Our study was not able to determine clearly whether they addressed oropharyngeal lateral wall-related obstruction seen during drug-induced sleep endoscopy because sleep apnea surgeons commonly use techniques that combine these techniques and others. Therefore, we were not able to separate the palate surgery procedures performed on the study participants into distinct types in order to compare them.
New research showing good results after expansion sphincter pharyngoplasty in those with markedly enlarged tonsils
A study published this month from a team at Seoul National University showed that 2/3 of patients with oropharyngeal lateral wall-related obstruction achieved a surgical response after tonsillectomy and expansion sphincter pharyngoplasty. I found this study intriguing because it was the first to look at this procedure in the specific subgroup of patients with this finding on drug-induced sleep endoscopy.
The challenge with using the study findings to apply to all patients is that the study included only patients with markedly enlarged palatine tonsils (grade 3+ or 4+). Because palatine tonsils are located in the sides of the throat, when they are markedly enlarged it is hard to tell whether collapse of the oropharyngeal lateral walls is related to the tonsils alone or whether there is additional lateral wall tissue contributing to airway obstruction. As I mentioned above, our drug-induced sleep endoscopy study did not include those with markedly enlarged tonsils, and the reason is that tonsils this large can interfere with understanding the potential contribution of other structures (including the tongue and epiglottis) that are examined with drug-induced sleep endoscopy.
The bottom line: without markedly enlarged tonsils, how much better is expansion sphincter pharyngoplasty?
Many patients with oropharyngeal lateral-wall related obstruction can have excellent results with sleep apnea surgery. Individuals with markedly enlarged tonsils who also have oropharyngeal lateral wall-related obstruction during drug-induced sleep endoscopy can have excellent results with tonsillectomy and expansion sphincter pharyngoplasty – although they may do well after tonsillectomy alone. What remains unclear is how well those without markedly enlarged tonsils who also have oropharyngeal lateral wall-related obstruction do after these newer palate procedures and whether those results are clearly affected by other structures contributing to airway obstruction.