Letter 1, Issue 3.4

Practices that Can Impact Proper Assessment of the Upper Airway Volume

Ahmed I. Masoud, BDS, MS
Department of Orthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia; Department of Orthodontics, College of Dentistry, University of Illinois, Chicago, IL; PhD candidate, Graduate Program in Neuroscience, University of Illinois, Chicago, IL

Upon reading the title “Differences in Volume and Area of the Upper Airways in Children with OSA Compared to a Healthy Group” by Rossi et al.1 in the July 2016 issue of the Journal of Dental Sleep Medicine, I was very excited. However, some of that excitement faded after reading the article. In my humble opinion I thought the study had multiple flaws, but I wanted to focus on three major issues:

1. The objective of this research was to “verify the differences in the volume and areas of the UA among children with OSA who have had adenotonsillectomy but continue to have persistent OSA, and a control group of healthy children.” Seeking that, the authors stated that in the study group “all the patients had undergone adenotonsillectomy or had been excluded of having hypertrophic tonsils; but they all had OSA symptoms.” This statement might just need clarification but from what I understand, there were patients with OSA symptoms who have “not undergone adenotonsillectomy” but were included in the study group because the tonsils were not hypertrophic. I hope my interpretation is wrong because if this is true then this causes major flaws:
a. No definition of hypertrophic tonsils was used. An objective measure such as a standardized palatine tonsillar hypertrophy grading scale could have been used.2 Followed by exclusion of subjects with 2+, 3+, and 4+ tonsils.

b. Simply excluding subjects with hypertrophic tonsils does not exclude subjects with enlarged adenoids. It is true that they are both lymphoid tissues and their sizes should hypothetically be correlated; however, this has not been shown to be the case. Hypertrophic tonsils and adenoids do not necessarily co-exist, and the size of the tonsils cannot be used to predict the size of the adenoids.3,4 Furthermore, there are surgeons who do not remove the adenoids completely and remnant tissue is left behind, in addition to surgeons who only remove the tonsils and leave the adenoids untouched. This should have been checked on the CBCT.

c. It contradicts the objective of the article since subjects without adenotonsillectomy were included in the study group.

2. In most anatomical books and papers the nasopharynx “lies behind the nasal cavity above the soft palate.” 5,6 The inferior limit in the current article extended far inferiorly that it included the soft palate. Putting that atypical definition aside, the soft palate thickness may increase as a result of vibration or inflammation when snoring.7 Since the authors in the current article concluded that “children with persistent OSA symptoms after adenotonsillectomy present with narrowing of the nasopharynx” and the nasopharynx they used contained the soft palate, the soft palate might have played a role in the persistence of the symptoms in addition to the narrowing of the nasopharynx and should have been discussed.

3. The authors stated that subjects were “placed in the tomography room in a sitting position with their head parallel to the Frankfurt plane.” How can the head be parallel to the Frankfurt plane? An important factor affecting airway analysis is head position.8,9 The method to orient the head should be clearly described.


Masoud AI. Practices that can impact proper assessment of the upper airway volume. Journal of Dental Sleep Medicine 2016;3(4):139–140.


1. Rossi RC, Rossi NJ, Filho EI, et al. Differences in volume and area of the upper airways in children with OSA compared to a healthy group. Journal of Dental Sleep Medicine 2016;3:81–7.

2. Chan J, Edman JC, Koltai PJ. Obstructive sleep apnea in children. Am Fam Physician 2004;69:1147–54.

3. Stearns M. The relationship of adenoid weight to tonsillar weight. J Laryngol Otol 1983;97:519–21.

4. Donnelly LF, Casper KA, Chen B. Correlation on cine MR imaging of size of adenoid and palatine tonsils with degree of upper airway motion in asymptomatic sedated children. AJR Am J Roentgenol 2002;179:503–8.

5. Aboudara C, Nielsen I, Huang JC, Maki K, Miller AJ, Hatcher D. Comparison of airway space with conventional lateral headfilms and 3-dimensional reconstruction from cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2009;135:468–79.

6. Mittal RK. Motor function of the pharynx, esophagus, and its sphincters. Integrated systems physiology: from molecule to function to disease. San Rafael, CA: Morgan & Claypool Life Sciences, 2011.

7. Pirila-Parkkinen K, Lopponen H, Nieminen P, Tolonen U, Pirttiniemi P. Cephalometric evaluation of children with nocturnal sleepdisordered breathing. Eur J Orthod 2010;32:662–71.

8. El H, Palomo JM. Measuring the airway in 3 dimensions: a reliability and accuracy study. Am J Orthod Dentofacial Orthop 2010;137(4 Suppl):S50 e1–9; discussion S-2.

9. Guijarro-Martinez R, Swennen GR. Cone-beam computerized tomography imaging and analysis of the upper airway: a systematic review of the literature. Int J Oral Maxillofac Surg 2011;40:1227–37.


Submitted for publication August, 2016
Submitted in final revised form September, 2016
Accepted for publication September, 2016

Address correspondence to: Ahmed I. Masoud, Department of Orthodontics, Faculty of Dentistry, King Abdulaziz University, PO Box 80209, Jeddah 21589, Saudi Arabia; Tel: +966503602125; Email:


Dr. Masoud has indicated no financial conflicts of interest.