Evaluation and Management of Pediatric Obstructive Sleep Apnea that Persists after Tonsillectomy and Adenoidectomy
Sally R. Shott MD
Cincinnati Children’s Hospital Medical Center
University of Cincinnati Department of Otolaryngology Head and Neck Surgery
In my last article, I discussed that although removal of the tonsils and adenoids (T&A) will likely improve the degree or severity of airway obstruction, in children with Down syndrome (DS), it does not always totally cure obstructive sleep apnea (OSA). Because of risk of residual obstruction, a sleep study or polysomnogram (PSG) should be done in all children with DS after their T&A. It is important to determine how much residual sleep apnea might still be present in order to determine if further treatment is needed.
Evaluation of sites of obstruction that might persist after T&A
A PSG provides objective data regarding the degree of residual OSA, but it does not identify at what level or levels of the airway the obstruction is occurring. In the evaluation of the upper airway for obstruction that could potentially cause sleep apnea, there are several anatomic sites where obstruction can occur: The nose and nasopharynx, the posterior oropharynx, the soft palate level, the lateral pharyngeal walls and/or at the level of the hypopharynx with obstruction at the base of the tongue. In children, obstruction can also occur at the level of the voice box or larynx. Diagnosing the site or sites of obstruction in children can be more difficult compared to adults due lack of cooperation during the examination. A good oral exam and nasal exam is important. Persistent airway obstruction could be from a deviated nasal septum or enlarged nasal turbinates or polypoid changes within the nose. Nasal polyps are less common in children but a good exam should be done to rule these out. The hard palate should also be examined. Since the hard palate also represents the floor of the nose, a high arched palate could have a significant effect on nasal resistance and obstruction. Lateral wall collapse of the posterior oropharynx has also been also shown to contribute to OSA. Edema or swelling of the posterior oropharyngeal wall may suggest gastroesophageal reflux contributing to a decrease in the airway size.
Radiographic studies can be useful to evaluate possible sites of obstruction. A lateral neck x-ray can show regrowth of the adenoid tissues and can also identify enlarged lingual tonsils.
Flexible endoscopy can be done in the office, examining the nose, the nasopharynx for possible adenoid regrowth, the posterior oropharynx, the base of tongue for enlarged lingual tonsils (another area of tonsil tissue that sit at the base of the tongue) and the larynx. We used to think that laryngomalacia, a condition where the tissues of the voice box or larynx collapse over the top of the vocal cords, only occurred in newborns or babies. However, we now see that it occurs in older children and can be a cause of persistent OSA.
Whereas the office exam is done with your child awake, it does not account for the collapsibility of the airway that occurs with muscle relaxation during sleep, and an exam during sleep is also recommended.
Examination of the airway during sleep: Cine MRI and DISE
The two current types of examination of the upper airway during sleep are the cine MRI and drug induced sleep endoscopy or DISE. The cine MRI provides a high-resolution examination of the dynamic airway and upper airway of obstruction in children, without the added risk of radiation exposure. It is particularly helpful in the evaluation of children with multiple sites of obstruction, such as is seen in children and adults with Down syndrome. This study is obtained with mild sedation administered by an anesthesiologist. In the cine MRI, 128 consecutive images are done over 2 minutes during episodes of airway obstruction. The images can then be displayed in a “cine” format, creating a real time “movie” of the airway motion. Dynamic motion of the airway is seen and the site or sites of obstruction can be seen. In addition, due to the increased brightness of lymphoid tissue compared to surrounding soft tissue and muscle on T2 weighted images, the cine MRI clearly delineates the actual thickness of adenoid regrowth that might be present and also can show the amount of lingual tonsil hypertrophy that might be present at the base of the tongue.
The cine MRI also allows for multiple levels of the airway to be assessed at the same time, identifying both primary and secondary sites of obstruction. This is particularly helpful in children who have multiple sites of obstruction and more complex obstruction, something that is frequently seen in children with DS. This is not possible with endoscopic airway evaluations. The various views of airway that are possible with the MRI allow for characterization of the pattern of collapse. It can be in the anterior-posterior direction, collapse of the lateral walls, or both where there is circumferential collapse. These patterns of collapse are important in determining further treatment options.
In children with DS, the base of tongue is one of the major sites of obstruction along with recurrent adenoids, each occurring in 63-74% of the children. Enlarged lingual tonsils are also commonly seen.
Drug induced sleep endoscopy (DISE)
Similar to the MRI exam, the goal of DISE is to evaluate the upper airway with mild sedation that is as similar as possible to natural sleep. This evaluation is done in the operating room with an endoscope. DISE includes a good evaluation of the nasal passages, the nasopharynx, the soft palate and oral cavity, the base of tongue and also the larynx, allowing an evaluation for the presence of laryngomalacia. The trachea can also be examined. Patterns of collapse can be determined also. Studies have shown that if mild OSA is present, it is more likely that a single site of obstruction will be identified with DISE, but if more severe OSA is present, it is more likely that multiple sites obstruction will be seen.
Treatment of persistent OSA after T&A in children – Medical Treatments
Several studies have shown that in cases of mild residual OSA, nasal steroid sprays (eg. Flonase, Nasonex) and anti-leukotrine medications (eg. Montelukast or Singulair) are effective in treating mild OSA. Therefore, if your child has only mild OSA after their T&A, with an obstructive index of less than 5 on their post-op PSG, these medications can be used. A follow-up PSG should be done 6-12 months after starting these medications to confirm their effectiveness.
Positive Airway Pressure Therapy: CPAP and BiPAP
Positive airway pressure therapy with CPAP or BiPAP continues to be a first line treatment of residual moderate to severe OSA that persists after T&A. CPAP and BiPAP have proven successful therapeutic results, if they are used. Compliance in typical adults is unfortunately only 30-40% and you might expect even lower compliance in children with developmental delays, but studies have shown over 50% success and effective use in children with DS. This success in this type of treatment requires that the child’s parents take an active role in having their child wear the CPAP. If worn regularly, this therapy provides almost 100% successful treatment of the OSA.
Oral appliances are one of the newer advances in the treatment of OSA. These devices enlarge the pharyngeal airway using mechanical forces. Dental appliances help to pull the jaw forward during sleep and can be considered in older children who have all secondary dentition in place and mild to moderate OSA. In children with high arched palates and mild residual OSA, rapid maxillary expansion, or palate expanders, present another option of treatment. In addition to the increased nasal resistance associated with high arched palates, there can also be associated alterations in tongue position which contribute to airway narrowing, especially at the base of the tongue.
Outcome studies on the use of oral appliances have been done mainly in adults with variable success. Better results are seen in those who have mild to moderate OSA, those who are less overweight, have a greater protrusion range, and in patients who have positional apnea. Some patients are better able to tolerate CPAP if they are also wearing a dental appliance.
In children who continue to have moderate to severe OSA and who have failed a trial of CPAP, further surgery to treat the residual OSA needs to be considered. Frequently there will be obstruction at multiple levels of the airway. The impulse is to therefore address multiple sites with a single, multi-level surgery and this is commonly done in adults. However, a study by Prager et al. showed an 8.2% incidence of oropharyngeal scarring and stenosis in 48 children who underwent multi-level surgery that included lingual tonsillectomy for OSA in children. Because of this, staged surgeries are recommended. It has also been shown that at times, solitary surgical improvements in airway size at one level can change overall airway dynamics and reduce airway collapse at other levels.
Current surgeries available for children have been done traditionally in adults with varying degrees of success that rarely reach above 50-60% in cases of moderate and severe OSA. In view of this, we usually do not suggest surgical intervention unless medical options such as CPAP have not been successful.
Studies have shown that much of the residual obstruction seen in children with DS occurs at the base of tongue, either from enlarged lingual tonsils, an enlarged tongue or macroglossia and/ or from the tongue falling back during sleep also called glossoptosis. Removal of enlarged lingual tonsils has been shown to be 60% effective in reducing OSA to normal or mild OSA in children with DS. There are several procedures that address the enlarged tongue (macroglossia) or the tongue falling back in the airway during sleep (glossoptosis). These surgeries are designed to either reduce the volume of the posterior tongue or to immobilize the tongue base to prevent collapse of the tongue during sleep. These surgeries include the midline posterior glossectomy, genioglossus suspension surgeries or the hyoid suspension surgery.
If there is airway collapse from the side or lateral walls of the airway collapsing, and/or from the soft palate collapsing, surgeries often referred to as a uvulopalatopharygoplasty or UP3 can be done.
If laryngomalacia is present, with collapse of the tissues above the vocal cords, a surgery called a supraglottoplasty is an option where some of this collapsing tissue is removed.
Hypoglossal Nerve Stimulator Implantation Surgery
There is currently a multi-institutional study being done investigating the use of the hypoglossal nerve stimulator (HGN) for treatment of OSA in children with DS. This type of treatment has been used in adults with good success for about 5 years. Initial results on 21 children with DS who have had this surgery is very encouraging. This device stimulates the branches of the motor nerve to the tongue, the hypoglossal nerve, during sleep. This stimulation is paced with respirations and acts to tense the posterior tongue and pull it forward slightly during sleep. Once turned on when the child goes to bed, there is a delay before the device starts to work, allowing the child to be asleep before it starts to work.
There are, however, limitations in regards to who can be a candidate for this promising treatment. The child cannot be overweight and the type of airway collapse seen on DISE must be a specific pattern of collapse. Regardless, this is a very promising option.
DS is associated with midface hypoplasia. When the mid-portion of the facial bones are smaller than usual, this affects the overall size of the airway. In older children, surgery to enlarge the midface is sometimes required to address OSA. This might include surgery to enlarge or advance the upper jaw or maxilla, the lower jaw or mandible, or both. This is ideally reserved for older children with DS where the majority of their facial growth has occurred.
Parents will frequently ask me WHY they need a PSG after their child has had a T&A because they think there are no other options of treatment available if residual OSA is present. As you can see, there are many treatment options, depending on the site or sites of residual obstruction. Endoscopic exams and radiologic evaluations such cine MRI and DISE are helpful to identify the locations of residual obstruction. Medical and surgical options are available. CPAP/BiPAP can be successful but compliance is difficult to achieve in the pediatric population and parents must take an active role in achieving success with CPAP use. In general, we like to try CPAP treatment before considering most surgical options.
It is important that if further surgery is done, that another post-operative PSG be repeated several months after surgery to confirm that adequate improvement in the OSA is achieved. In addition, because of the changing body size and shape that is inherent in the growing child, there is a need for continued vigilance for recurrence of the airway obstruction as the child grows and as their body habitus changes. Because sleep apnea can be complex with multiple treatment options, at Cincinnati Children’s Hospital we have established the Upper Airway Center to provide a multi-disciplinary approach to each child’s individual type of airway obstruction during sleep.
Sally Shott MD.
Dept of Pediatric Otolaryngology
Cincinnati Children’s Hospital Medical Center
3333 Burnet Avenue
Cincinnati, Ohio 45229