Drug-Induced Sleep Endoscopy

1 Introduction

Nico de Vries, Ottavio Piccin, Claudio Vicini, and Olivier M. Vanderveken

Abstract

The two cornerstones of obstructive sleep apnea (OSA) workup are sleep study and drug-induced sleep endoscopy (DISE); the latter comes into play in case alternatives to continuous positive airway pressure (CPAP) therapy are considered. This book provides all information on drug-induced sleep endoscopy that is presently available. Some of the world's key opinion leaders in this field, accumulating a vast experience of tens of thousands of DISE procedures, have collaborated in this project.

Keywords: obstructive sleep apnea, history, drug-induced sleep endoscopy

1.1 Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a unique disease in the sense that it is both very commonplace and serious.

Incidence in adults was earlier reported to be 2 to 4% of the adult population but recent research, particularly in Switzerland, has shown that it is actually much higher-up to 49% of the male adult population has an apnea hypopnea index above 5.

OSA complaints include loud snoring, excessive daytime sleepiness, tiredness, concentration loss, impaired intellectual performance, among others. Basically, everything that one can imagine as a consequence of repetitive insufficient good sleep can happen.

OSA consequences are, particularly in advanced disease, increased cardiovascular risk, high blood pressure, weight gain, and higher risk of getting involved in accidents.

While as much as 80% of patients with OSA are undiagnosed, awareness is on the rise.

In case of suspicion of OSA, one starts with meticulous medical history taking. Thereafter, an OSA specific physical examination follows. Subsequently, a form of sleep study is scheduled. This is usually a polysomnography or polygraphy in a sleep laboratory or at home. Although in the past this was often regarded as sufficient information to start treatment with continuous positive airway pressure (CPAP), presently therapies other than CPAP are gaining ground as well. Not surprisingly, in this era of personalized medicine, treatment diversification and shared decision-making, the one-size-fits-all, exclusive concept of CPAP therapy is gradually being abandoned.

Current alternative treatments include oral device treatment, positional therapy in case of positional OSA, weight loss in case of overweight, all forms of upper airway surgery, either at the same time or staged, upper airway stimulation and treatment combinations.

In case surgery is considered, drug-induced sleep endoscopy (DISE) is pivotal and often performed after the sleep study has confirmed the diagnosis of OSA. DISE aims at mimicking the normal situation during sleep as closely as possible. While it is well understood that natural sleep and drug-induced sleep are not the same, there is no other method to assess the severity, level(s), and configuration of obstruction of the upper airway that rivals DISE as a viable alternative. DISE as a selection for surgery however remains somewhat controversial, since DISE opponents argue that the evidence that the results of sleep surgery after DISE are better than surgery without DISE is lacking. It is, in fact, even more controversial if DISE should be performed in case oral device therapy, positional therapy, or combination treatment is considered.

This book aims at providing state-of-the-art information on all aspects of DISE. The book starts with background information and historical perspectives, and continues with indications and contraindications. Many different systems have been described and proposed. Which system(s) are presently considered the most useful and which one is mostly used?

Preparation for DISE and informed consent are highlighted. Periprocedural care as well as equipment and documentation is discussed. Some centers perform hundreds of DISEs per year. In case of high-volume of DISEs, good organization, training, and logistics are crucial. Patient preparation and positioning are important. The choice of medication and drug administration and other anesthesiologic aspects deserve proper attention. Should DISE be performed always in case surgery is considered, or only on indication, and if so, which indications are there? How do DISE findings translate into therapeutic surgical and nonsurgical treatment planning? Is DISE safe? What setting is needed? What are the specific indications and contraindications, which personnel is needed, should it be performed in the OR, or can it be performed in a dedicated endosuite outside the OR complex? Is it necessary that the endoscopist and surgeon are the same? Which medication and in which dosage is recommended?

During the procedure itself, passive maneuvers such as chin lift, jaw trust, mouth closure, and titration bite can be performed. Should all these maneuvers always be performed as a matter of routine? Should DISE be performed only in case upper airway surgery or upper airway stimulation are considered or also in cases in which oral device treatment is considered? What is known about the positive and negative predictive value of a maneuver such as jaw thrust? Should DISE be performed in case positional therapy is considered? While previously it was advised to perform DISE in supine position because the obstruction is in that particular position at its most, it can be argued that it is better to perform DISE in lateral position, in case positional therapy is offered either as monotherapy or combined with another treatment modality, or in both supine and lateral position. What is the predictive value of rotation of the head or both head and trunk during DISE? Rotation of the head is only easier and quicker, but is it the same as rotation of both head and trunk? Is it necessary to assess both left and right lateral position, or is the outcome the same? What is the predictive value of a combination of jaw trust and rotation of the head or both head and trunk in case combined positional therapy and oral device treatment are considered?

Work in progress includes the development of a prediction model for such maneuvers, as a selection tool for oral device therapy and positional therapy. What is the predictive value of a combination of jaw trust and rotation of the head or both head and trunk in case combined positional therapy and oral device treatment are considered?

When DISE is performed lege artis, and certain requirements are fulfilled, complications are fortunately extremely rare.

Outcomes of large DISE series are described. Intuitively, no obstruction is better than partial obstruction: partial is better than total, anteroposterior and lateral obstruction are better than concentric, and unilevel is better than multilevel. How do all such findings lead to rational treatment advices? For example, is the advice for surgery of a partial and total collapse of the tongue the same or different? Does multilevel obstruction always implicate multilevel treatment or multilevel surgery, and at the same time or staged? In which situation(s) do DISE findings lead to the advice of not performing upper airway surgery?

Usually, but not always, medical history, results of the sleep study and DISE are inline, for example, a history of mild complaints, and mild-to-moderate OSA in the sleep study, correlates with mild obstruction during DISE (one level of obstruction instead of multilevel, no partial obstruction instead of total obstruction, AP-collapse vs. concentric). On the other hand, a history of severe complaints, moderate-to-severe OSA in the sleep study, usually correlates with convincing collapse patterns as multilevel or even obstruction on all levels, total and concentric. However, sometimes there seems to be a mismatch between medical history, sleep study, and DISE findings. One should be aware of this and, if needed, not hesitate to repeat the particular study (either the sleep study or DISE) that does not seem to make sense.

The significance of special findings such as complete concentric collapse of the palate and epiglottic collapse are highlighted. Complete concentric collapse of the palate is "bad news" for standard palatal surgery, as it is regarded as an absolute contraindication for upper airway stimulation, and results of oral device therapy are less favorable as well. Epiglottis collapse occurs in some 8%, and was long regarded as an important justification to perform DISE anyhow, since the only way to discover it is DISE. Recent research shows that epiglottis collapse almost exclusively occurs during DISE in supine position. The consequences are obvious and important.

An exciting recent development is hypoglossal nerve stimulation. The role of DISE before and after hypoglossal nerve stimulation (in case of unexplained failure of the therapy) is critically appraised. In such a situation, DISE often reveals that the effect of upper airway stimulation on the base of tongue collapse is good, but there is no palatal coupling with residual palatal collapse as a consequence. Additional palatal surgery can be indicated in such a case. Higher and lower power settings and different settings-such as monopolar versus bipolar-can be tested as well and might have important clinical consequences.

DISE can prove to be of value in CPAP titration and in case of unexplained CPAP failure. The role of DISE in craniofacial diseases is discussed as well.

A critical discussion of DISE in children, both from an European perspective as well as a US point of view, follows. What is the role of DISE in OSA among children? What is the difference in the role, findings and therapeutic options of DISE in kids and adults? Are the classification...