Discussion
To the best of our knowledge, this is the first report to describe the
otorhinolaryngological management in Taiwanese patients with MPS. Our
results emphasize that otorhinolaryngological management is important
for patients with MPS as they have problems of language development and
poor quality of life due to the high frequency of ear disorders
[17]. For better prognosis of MPS, it is important to treat in early
stage. The otorhinolaryngologist and audiologists play important roles
in follow-up and treatment of MPS patients. Patients need better and
long-term follow-ups due to high incidence of recurrent serous otitis
media with conductive hearing loss and progress to sensorineural hearing
loss.
In previous studies, an average of 75% of cases (range 59.7% to 89%)
have hearing loss [18]. Various types and degrees of hearing loss
can be seen in MPS patients [7-8, 19-21]. Conductive hearing losses
are more common in MPS patients due to frequent chronic middle ear
effusion and Eustachian tube dysfunction. The incidence and etiology of
sensorineural hearing losses are unknown [7]. In our study,
conductive hearing losses are more than sensorineural hearing losses
(19.0% v.s. 16.7%). Although conductive hearing loss can be improved
by adenoidectomy and tympanostomy with ventilation tube [21],
sensorineural hearing loss is still a problem to be overcome. In our
study, 34.3% of patients had improved hearing after surgery. Besides,
according to the infection score system, we noticed that the severity of
respiratory tract and otological infections improved after ENT surgery.
It may cause by the improvement of adenoid hypertrophy, tonsillar
hypertrophy and OME with decreased infection risk.
Ventilation tubes are advised to apply in MPS patients with recurrent
OME and hearing loss. However, some families rejected to undergo
ventilation tubes insertion because they were afraid of the risk of
general anesthesia during operation. In some cases, the operation was
very difficult or impossible because of the severe deformity of external
ear canal that the ear drum was difficult to approach. And in some
cases, we advised patients to apply hearing aids, but the
socioeconomical inadequacy made them hard to come to follow-ups and
obtain these aids. This is the reason that some patients still have
conductive hearing loss after ERT. Besides, ERT could not improve
sensorineural hearing loss [22].
Whereas otologic problems influence the quality of life, upper airway
obstruction can cause serious morbidity and mortality. Most respiratory
problems are caused by the changes of soft tissue of the tonsils,
adenoids, tongue, lingual tonsils and the stiffness of oropharynx and
temporomandibular joint. Oropharyngeal stiffness and collapse become
severe when the disease deteriorates and can cause significant airway
obstruction [23]. The degree of upper airway obstruction may range
from OSA to life-threatening airway emergencies, and airway evaluation
is necessary and challenging. The results of airway examinations vary in
case-by-case patients [24]. In our study, the upper airway
obstruction (patients who had stridor, suprasternal retractions, and
change of voice) rate was 76.2%, compared with 38% [20], 48%
[18], and 92% [25] in other studies. All types of MPS patients
had similar symptoms. Consequently, it is necessary to perform
adenoidectomy in patients with purulent, recurrent, and chronic symptoms
such as OME, snoring and sleep apnea [14]. Though tonsillectomy and
adenoidectomy can help those with OSA at first, they may need nocturnal
oxygen treatment, and even tracheostomy in advanced cases [26].
Anesthetic risks increase in patients with MPS because they have
macroglossia, temporomandibular joint stiffness, difficult or failed
intubations, abnormal laryngeal anatomy, trachea deformity and
subglottic narrowing [27, 28]. Before surgery, these patients need
examination using a flexible bronchoscope to survey the exact extent and
severity of airway obstruction [7, 9].
The patient history and physical examination are necessary for
evaluation of OSA initially, but the degree of obstruction before and
after surgery should be studied by polysomnography and
laryngobronchoscopy [25,29]. In our study, 28.6% of our patients
still had OSA after adenotonsillectomy due to macroglossia and
oropharyngeal stiffness. This condition is also found in other OSA
patients without MPS. The reason may be that even though the structure
and the tension of upper airway improved after surgery, it could
deteriorate after years. We should also pay attention to whether the
dose of ERT is enough or not. ENT care and airway evaluations should be
provided before we take these patients to the operation room and it
could provide more safe intubation and extubation. Choosing the suitable
size of endotracheal tube and the method of intubation potentially
decrease the risk of complications related to intubation during general
anesthesia and surgery [30].
This study has several limitations. We had only 42 patients in this
study because they had complete medical histories of
otorhinolaryngological treatments. Besides, we did not perform sleep
studies in every patient because this study was designed for medical
retrospect. It is necessary to complete their examinations in the
future. It is also needed to evaluate the quality of life of patients
formally by visual analogue scale (VAS) as previous study [16].