The complex of lymphoid tissue encircling the pharynx is referred to as Waldeyer's ring. This
complex includes (1) adenoids/pharyngeal tonsils, (2) lateral pharyngeal bands, (3)
faucial/palatine tonsils, and (4) lingual tonsils.
The classic growth curves published by Scammon and associates1 have been widely reproduced
and have led to the belief that the lymphoid growth curve applied to tonsils and adenoids. This
lymphoid growth curve indicates a rapid rise in infancy and early childhood and a continued but
slower increase during late childhood and prepuberty, peaking before adolescence and then
gradually declining thereafter to adult values. But do the tonsils and adenoids display this growth
cycle as represented by the Scammon data?
The Scammon lymphoid curve was based on postmortem material collected about 50 years ago
and did not include measurements of the tonsils and adenoids. Rather, it was based on weight of
the thymus, Peyer's patches, lymphoid follices in the appendix, and mesenteric lymph nodes.
Pruzansky2 pointed out that Scammon sampled a population subject to infectious diseases that
have been eradicated in the developed countries of the world. "Thus, Scammon's subjects
reflected stresses of infection and other environmental factors quite different from those that
prevail today." Pruzansky further pointed out that, although tonsils and adenoids are part of
Waldeyer's ring, they have disparate embryonic origins and cytology.
Hollender and Szanto3 believe that the incidence of nasopharyngeal lymphoid hyperplasia in
older persons is relatively high. Lymphoid hyperplasia was a common finding in their autopsy
specimens from subjects after the sixth or seventh decades of life, suggesting that lymphoid
regression need not necessarily occur.
Pruzansky,2 in a mixed cross-sectional and longitudinal cephalometric study, indicated a
considerable variation in size of the adenoids in all age groups. Further, he found that in the same
person the size of the tonsils did not necessarily mimic the size of the adenoid. Pruzansky
speculated that the growth curve attributed to tonsils and adenoids is not a true curve but, rather,
an individual response to variable stress.
Subtelny,4 using serial cephalometric head plates and laminagraphs, found that the adenoid
tissue follows a definite growth pattern. The adenoid tissue grows, predominantly downward and
forward, rapidly during the early years of life (to approximately age 3) and then at a somewhat
retarded rate until its greatest bulk is attained. In the Subtelny sample, the peak mass was
observed to occur from the age of 10 to the age of approximately 14 to 15 years. The extreme
range observed might be explained by the fact that there was no sexual discrimination in the
study. After the peak of adenoid growth is attained, the growth process seems to reverse itself
and the adenoid tissue progressively decreases in mass. By adulthood the adenoids have usually
It is important to remember that the adenoid tissue is growing within a constantly changing
environment. Normally, the nasopharynx enlarges to accommodate the growing adenoids, thus
maintaining a patent nasopharyngeal airway. Any imbalance between this increase in the
dimensions of the airway and the concomitant growth of the adenoid may result in reduced
patency and nasopharyngeal obstruction.4 Enlarged faucial tonsils will cause the soft palate to
rest on their upper pole instead of on the dorsum of the tongue and further displace the dorsum of
the tongue downward and forward,5,6 contributing to an open-mouth posture and possible
nocturnal snoring and sleep apnea.
Immunologic aspects of tonsils and adenoids
"Does tonsillectomy and adenoidectomy compromise the microbial defense or local
immunologic functions of the host?" The effects of such surgery is the focus of a sustained
controversy which complicates indications for tonsillectomy and adenoidectomy.
Tonsils and adenoids, because of their strategic locations, constitute the primary sites of initial
exposure to inhaled or ingested antigens. Moray and Ogra7,8 state that the nasopharyngeal
mucosa, tonsils, and adenoids are replete with immunocompetent tissue. As such, "the tonsils
may act as both regional and nonregional lymph nodes and serve as an initial trapping
mechanism for a variety of antigens."9
In addition to the "gatekeeper" sites and function, the tonsillar lymphoid tissues may be involved
also in the development of the human immune system, in a fashion similar to that of the
thymus.10,11 Normal newborn infants are essentially agammaglobulinemic at birth, with the
exception of transplacentally acquired maternal immunoglobulin G. After birth, and subsequent
to mucosal colonization with bacteria and exposure to other antigens, the immune system begins
to mature rapidly. Godrick and Patt12 suggest that tonsillar tissue may be more reactive
immunologically than other developing lymphoid tissue in the early weeks of life. Conceivably,
during the early years of life, all available immunocompetent lymphoid tissue may be necessary
for optimal maturation and development of immunoglobulins.
Waldeyer's ring is continually affected by the changing antigen environment in which a person
lives, and thus continuously stimulates immunologic responses.13 Certain immune-deficient
states, such as the Bruton agammaglobulinemia, seem to corroborate the vital role of these
tissues in immune balance, since the tonsils in these patients are poorly developed.14 Also,
recent findings from a study of a large group of 20- to 55-year-old women indicate that those
with a history of tonsillectomy had a lower mean concentration of gamma globulin than those
who had not had the operation.15
The immune system has been related also to combatting malignancies. Vianna, Greenwald, and
Davies16 suggested that the incidence of Hodgkin's disease may be higher among persons who
have undergone tonsillectomy. However, the mechanism underlying this association is not clear.
Changes in cellular immune response secondary to tonsillectomy may be a contributing factor.
On the other hand, other well-controlled epidemiologic studies have failed to discern such an
association.17,18 At present, and until more evidence is forthcoming, the relationship between
tonsillectomy, malignancy, and alterations in the immune system is unclear. Since
adenoidectomy is usually performed in conjunction with tonsillectomy, there is little or no
information relating specifically to the clinical, immunologic, and epidemiologic aspects of
adenoidal disease. It appears that the degree to which adenoids are exposed to exogenous
antigens is similar to that of tonsils, and adenoids would, therefore, appear to be
immunologically reactive. Preliminary data from the laboratory of Morag and Ogra7 suggest that
adenoids may participate only minimally in the local immune response and that the effects of
adenoidectomy on nasopharyngeal immune response may not be as pronounced as after
Tonsillectomy and adenoidectomy
During the past 60 years a more rational view of tonsillectomy and/or adenoidectomy has
emerged. The more conservative approach to the surgical procedures may be due to an increased
1. Immunologic considerations.
2. Allergic nasal symptoms. These symptoms, previously attributed to adenoidal hypertrophy,
are now being diagnosed more frequently.19
3. Antibiotics. The introduction of antibiotics in the 1940's and 1950's permitted a more
conservative management of lymphoid hyperplasia.20
4. Upper respiratory diseases. The realization by the medical profession that removal of tonsils
and adenoids does not significantly lower the incidence of upper respiratory tract disease.
5. Operative morbidity or mortality. Tonsillectomy and/or adenoidectomy are not without risk of
morbidity or mortality, although the incidence of such complications is low.21
Even though we are at present in a period of relative conservatism, tonsillectomy (usually
combined with adenoidectomy) is still one of the most frequently performed operations in the
United States.21 There has been a reduction in the number of tonsillectomies with
adenoidectomies performed during the past few years. A twofold increase during the same period
in the number of adenoidectomies without tonsillectomies, along with a slight increase in the
number of tonsillectomies without adenoidectomies, may represent a trend toward performing
the surgical procedures separately.22
To date, there is a lack of scientific evidence of actual health benefits resulting from these
surgical procedures. No question exists concerning the importance of operating in those rare
cases in which nasopharyngeal obstruction causes hypoxia, cor pulmonale, and congestive
cardiac failure or when difficulty in swallowing interferes with nutritional status.21 Yet some
pediatricians believe that, apart from these clearly urgent indications, tonsillectomy is rarely, and
adenoidectomy infrequently, indicated.
Tonsillectomy and adenoidectomy, either in combination or separately, are most frequently
performed to correct the following conditions: (1) recurrent or chronic throat infection or, more
specifically, pharyngotonsillitis, (2) hypertrophy, and (3) recurrent attacks of acute otitis media
or chronic otitis media with effusion.23 It must be recognized that the incidence and prevalence
of these conditions decrease as a function of age after the age of 6 years.24-26
Bluestone23 pointed out that all of the prospective clinical trials of tonsillectomy and
adenoidectomy conducted to date excluded from consideration children most severely affected
by conditions related to tonsils and adenoids. Instead, they tested the efficacy of tonsillectomy
and adenoidectomy in children in whom the indications of need for these procedures were
questionable or, at best, unimpressive. Bluestone23 listed from these studies the following results
of tonsillectomy and adenoidectomy:
1. A measurable, but not striking, reduction in the incidence and/or severity of throat
2. Some reduction in mouth breathing.28
3. A modest reduction in the incidence of otitis media reported in some studies,30,31 but no
reduction in others.27,28,32
No prospective controlled clinical trial of tonsillectomy and adenoidectomy in severely affected
children has been reported to date. Nor are data available on such children who have been treated
only medically or not treated at all.
"It may be fairly concluded, therefore, that in most of the conditions for which
tonsillectomy/adenoidectomy may be performed, the decision must be based either on
unwarranted interpretations of the results of existing studies, or on personal opinion or
experience. Similarly, it seems apparent that some of the decisions against operating also lack
scientific support . . ."23
An attempt to lessen the confusion has been undertaken at the Children's Hospital of Pittsburgh,
where a prospective controlled clinical trail is now in progress. It is hoped that this study will
provide clear indications for tonsillectomy and/or adenoidectomy.
Physicians are thus in a dilemma as regards decisions concerning the tonsils and adenoids, and
understandably so, considering the available evidence. As such, they may be unresponsive to the
requests by orthodontists who refer patients for tonsillectomy and/or adenoidectomy.
Nasal respiratory evaluation
The relationship of breathing patterns and the form of dentofacial structures and dental arches is
a subject of investigation and controversy among orthodontists. Much of the confusion stems
from the failure to establish clear-cut correlations between the functional problems and the
supposedly related morphologic characteristics.
Enlarged tonsils and adenoids, by compromising the airway space, have been implicated in
dentofacial abnormalities. Orthodontists are thus referring patients to physicians for
tonsillectomy and/or adenoidectomy to relieve respiratory obstruction. But is the diagnosis of
enlarged tonsils and adenoids and mouth breathing based on well-defined criteria? Also, is
craniofacial morphology undisputably influenced by respiratory mode?
Tonsil size is, from a clinical standpoint, a difficult assessment. There is no recognized "normal"
size for a tonsil. It is, therefore, arguable whether tonsils can be described as "enlarged."33 The
apparent size of the tonsil can be altered considerably when the tongue is protruded forcibly. A
child whose oropharynx looks normal with the tongue slightly protruded can make the tonsils
meet in the midline with maximum protrusion of the tongue. The tongue depressor also alters the
apparent size of the tonsils. If the tongue is firmly depressed, the patient gags and the tonsils
meet in the midline. Grossly enlarged tonsils can create an obstruction in the oropharyngeal
space dorsal to the root of the tongue. If obstruction is severe enough, the tongue may be
postured forward to maintain an adequate oropharyngeal space for respiration.5,6 A tongue that
appears protrusive, however, does not necessarily indicate enlarged tonsils, since any condition
leading to nasorespiratory obstruction might result in reposturing of the tongue to maintain a
patent oral airway. Macroglossia, while rare, does occur, and the tongue in these cases also
Adenoid size must be assessed relative to the dimensions of the nasopharynx. Adenoids are best
assessed clinically by direct nasopharyngoscopy, a procedure usually employed by
otolaryngologists. Orthodontists currently depend on lateral skull radiographs in assessing
adenoid size. Holmberg and Linder-Aronson34 found (1) that there was a significant relationship
between the size of the adenoids as measured on lateral skull radiographs and as assessed
clinically and (2) that the greater the size of the adenoid, as measured on lateral skull
radiographs, the less the nasal airflow. These radiographs reflect the nasopharynx in only two
dimensions, however, and differing opinions have been expressed concerning the accuracy of
Mouth breathing is usually defined as "habitual respiration through the mouth instead of the
nose."36 In reality, however, oral respiration nearly always implies a combination of nasal and
oral respiration. It does not seem to be a question of either-or, as many authors have asserted.
The question is, rather: "At what point, if any, does mouth breathing lead to dentofacial
In studies of airway obstruction, it has been customary to express degrees of obstruction in terms
of nasal resistance. Watson, Warren, and Fischer37 showed that the incidence of clinically
observable mouth breathing was greater among subjects with a nasal resistance above 4.5 cm.
water per liter per second. It is necessary, however, to consider each individual in relation to his
age-related norms, which are not yet available. Furthermore, nasal airflow in isolation, as
opposed to the estimate of relative oral/nasal flow, is less than satisfactory for the diagnosis of
Clinically, then, unless sophisticated measures are employed, it is currently impossible to
measure differentially and adequately the relative amounts of nasal and/or oral respiration.
Estimating nasal respiratory capacity, as many orthodontists do, by having the patient breathe
through each nostril separately, placing a cold mirror under the subject's nose, or placing
cotton/wool under the subject's nose is unreliable. Further, it must be emphasized that nasal
patency is not at all constant and can vary considerably within minutes in all subjects.39
The evaluation of nasal airway patency is complicated also by the fact that the airways may
clinically appear inadequate, but may be quite functional physiologically. Lip separation, or an
open-mouth habit, is not a reliable indicator of mouth breathing, because complete nasal
respiration often occurs in the presence of dental conditions which cause an open-mouth posture.
Similarly, a narrow nose is not necessarily characteristic of mouth breathers.
Holmberg and Linder-Aronson34 believe that frontal cephalometric radiographs provide a
reasonable assessment of the nasal airflow by subjective evaluation of airway capacity and are
valuable in diagnosing reduced nasal respiratory function. Montgomery and colleagues,35
however, state that conventional radiographs possess inherent limitations due to superimposition
and lack of soft-tissue detail. They claim that apparent airway impingement by the turbinates as
shown on posteroanterior radiographs is a poor indicator of airway size, since the turbinates may
not be located at the sites of the smallest portions of the airway.
Respiratory pattern and dentofacial form
What are the effects of reduced nasal respiratory function on the form of the facial skeleton and
the dental arches? This question has been debated for at least 100 years between supporters of
the genetic hypothesis and those in favor of environmental explanations and is still unresolved.
Tomes,40 in 1872, reported that children who are mouth breathers often have narrow, V-shaped
dental arches, while Kingsley41 stated, in 1888, that the V-shaped palatal form was an inherited
feature and, therefore, not related to mouth breathing.
More recently, mouth breathing has been incriminated in dentofacial deformities by LinderAronson,42 Quinn,43 Ricketts,44 and Subtelny.6 The experiments of Harvold and colleagues,45
in which nasal obstructions were created in growing monkeys, and Moss's "primacy of the
functional matrix in orofacial growth" support this idea.
On the other hand, Humphreys and Leighton47 failed to find significant evidence of a
relationship between mouth breathing and dentofacial form. Mouth breathing was found to be
associated with all types of malocclusion as well as with normal occlusions. This finding was
supported by Howard48 and Leech.49
Bushey's50 study concluded that "because naso-respiratory obstruction may be partial or
complete, mouth breathing may also be partial or complete, and thus offers a continuum of
physiologic adaptation related to a number of morphologic variations of the craniofacial
It is, therefore, by no means clear to what extent craniofacial morphology is influenced by
Respiratory dysfunction and dentofacial form, then, are the focus of much attention in
orthodontic circles. Orthodontists are thus in a dilemma as regards decisions concerning the
tonsils and adenoids, and understandably so, since the diagnosis of airway obstruction and
enlarged tonsils and adenoids is still largely subjective. Further, the evidence relating dentofacial
form to breathing patterns is inconclusive.
1. The removal of tonsils and adenoids during the growth period may compromise subsequent
local nasopharyngeal immunologic responses and over-all immunity to infections in the
respiratory tract, since (a) tonsils and adenoids are located strategically at sites of initial antigen
exposure and (b) tonsils are possibly involved in the development and maintenance of the
2. There is a lack of scientific evidence of actual health benefits resulting from tonsillectomy
3. The orthodontic diagnosis of airway obstruction and enlarged tonsils and adenoids is at
present very subjective.
4. The evidence relating dentofacial form to breathing patterns is inconclusive.
The tonsil and adenoid problem, then, while receiving much attention, is understandably
controversial. The potential for long-term adverse effects resulting from tonsillectomy and/or
adenoidectomy must be borne in mind and weighed against the possible advantages to be gained
by the surgical procedures in selected cases. More contact between orthodontists and physicians
is essential so that we may have a better insight into common therapeutic considerations and
problems. In this way, as much information as possible may be incorporated in the over-all
rationale that enters into the decision for performing tonsillectomy and adenoidectomy or
seeking an alternative method of treatment.
Thanks to Drs. R. Biggerstaff, O. Tuncay, and C. Tulloch, U.K.C.D., for constructive criticism.