Effect of nasal obstruction surgery on middle ear ventilation

Introduction Th e Eustachian tube has at least three physiologic functions with respect to the middle ear: ventilation of the middle ear to equilibrate air pressure in the middle ear with atmospheric pressure, drainage and clearance into the nasopharynx of secretions produced within the middle ear, and protection from nasopharyngeal sound pressure and secretions. Also, it is involved in ensuring air exchange in the middle ear [1,2].


Introduction
Th e Eustachian tube has at least three physiologic functions with respect to the middle ear: ventilation of the middle ear to equilibrate air pressure in the middle ear with atmospheric pressure, drainage and clearance into the nasopharynx of secretions produced within the middle ear, and protection from nasopharyngeal sound pressure and secretions. Also, it is involved in ensuring air exchange in the middle ear [1,2].
Maintaining the physiological pressure in the middle ear depends on the gaseous balance between air intake through the Eustachian tube and gas diff usion from the middle ear to the systemic circulation. Th e adequacy of ventilation through the tube plays a central role in preserving pressure equilibrium. When the tube opens during swallowing, air reaches the middle ear, equalizing the pressure between the external and the internal surface of the tympanic membrane [3,4].
Tympanometry and Eustachian tube function ( ETF) tests (Valsalva and Toynbee maneuvers) can assess the ETF; thus, they have been used widely in clinical and basic research investigations. Patients with tubal dysfunction often complain of a sensation of ear fullness, which is a consequence of the functional impairment of the Eustachian tube resulting from a ventilatory disturbance. However, despite the sensation of ear fullness, most patients show normal middle ear pressure as measured by tympanometry [5].
Th e tube is frequently involved in the pathological processes of the nasal, paranasal, and rhinopharynx cavities; therefore, nasal obstruction can alter ETF [6]. Th e pathogenesis of otitis media has been related to the presence of previous or concurrent nasal diseases, such as upper respiratory tract viral infection and allergy. In particular, allergic rhinitis is known to be one of the main causes of chronic nasal obstruction [7][8][9][10][11]. It has been reported that patients with even a minimal septal deviation have a tubal dysfunction with a consequent middle ear pressure depression [12].
Most of the patients complaining of nasal obstruction require surgery for relief in their nasal obstruction. Are these surgeries that can lead to improvement in the Effect of nasal obstruction surgery on middle ear ventilation Osama G. Abdel-Naby Awad a , Yehia M. Salama a , Mohammed El-Badry b

Aim
The purpose of this study was to reveal the role of nasal surgeries in changing Eustachian tube function (ETF) and middle ear ventilation.

Methods
This prospective study involved 30 patients with diffrent nasal pathologies causing nasal obstruction. The patients were subjected to diffrent nasal surgeries for treating their nasal obstruction. ETF tests in the form of (Valsalva and Toynbee manuvers) together with tympanometery were performed the day before the operation, and then repeated 30 days after removal of the nasal packs. Pre and postoperative Valsalva and Toynbee tubal function tests, tympanometery and ear fullness sensation were evaluated for both ears of each patient.

Results
Preoperatively, 47 (78.3%) ears were type A, 24 ears of them had poor ETF and 23 ears had good ETF. Thirteen (21.6%) ears were type C, all of them had poor ETF. The postoperative results of ETF tests were signi cantly better than preoperative results (P < 0.002).Signi cant improvement in tympanometeric values was also found (P < 0.05). Preoperatively, 28 patients (93.3%) had sensation of ear fullness. At 30 days after removal of nasal packs, 20 patients (66.7%) still had sensation of ear fullness, with signi cant improvement (P < 0.001).
ETF, middle ear pressure, and sensation of ear fullness? Th e aim of this work is to investigate the eff ect of nasal obstruction surgery on ETF and middle ear ventilation.

Patients
Th is prospective study included 30 patients who presented to the otolaryngology outpatient clinic at El-Minia University Hospital with a complaint of unilateral or bilateral nasal obstruction; they were surgically operated for correction of their nasal obstruction between July 2012 and July 2013.
Patients had diff erent nasal pathologies causing their nasal obstruction such as chronic rhinosinusitis, marked deviated septum, antrochoanal polyp, chronic hypertrophic rhinitis, and bilateral nasal polyposis. Twenty-eight of our patients had a sensation of ear fullness. After the nasal surgery, anterior merocel nasal packs (8 and 10 cm long in each nostril, pope epistaxis packing; Medtronic, Tallahassee, Florida, USA) were left in situ for 2 days.
Patients with tympanic membrane perforation, acute rhinitis, and one or a recent history of middle ear infection were excluded from the study. A total of 60 ears of 30 patients were examined. Detailed assessment of medical history was performed for each patient with a full ENT examination.

Design
ETF tests in the form of (Valsalva and Toynbee maneuvers) together with tympanometry were performed the day before the surgical operation, and then repeated at 30 days after the removal of nasal packs.

Equipment
Zodiac 401 (Madson-Zodiac 401, GN. Otometrics, Denmark) middle ear analyzer was used. Th e tympanograms were classifi ed in the standard manner according to Jerger [13]. A tympanogram with middle ear pressure peak between +50 and −100 daPa was classifi ed as type A. Tympanogram with middle ear pressure peak of −100 daPa or more negative was classifi ed as type C. A tympanogram with a fl attened peak of less than 0.3 ml admittance was classifi ed as type B.

Eustachian tube function tests Valsalva maneuver
To evaluate the ability to infl ate the middle ear actively, patients were asked to pinch the nose and infl ate the checks through forced expiration with the mouth closed until a sensation of fullness was achieved in the ears. Patients were then instructed to release the nose and refrain from further swallowing or mandibular movement and an experimental tympanogram was obtained in each ear. A tympanometric peak pressure shift (generally positive) between baseline and experimental tympanogram less than 10 daPa indicated poor ETF, whereas a tympanometric peak pressure shift greater than 10 daPa indicated a good ETF [14].

Toynbee maneuver
To evaluate the capacity to equalize the middle ear pressure and the rhinopharyngeal pressure, patients were asked to swallow while pinching the nose. Patients were then instructed to release the nose and refrain from further swallowing and mandibular movement, and an experimental tympanogram was obtained from each ear. Tympanometric peak shift (generally negative) between baseline and experimental tympanogram less than 10 daPa indicated poor ETF, whereas a tympanometric peak pressure shift of greater than 10 daPa indicated a good ETF.
Th e study was approved by the Institutional Review Board at El-Minia University. Because the study involved no deviation from existing standard therapy for these patients and no new drugs, individual consent was not required by the board; however, an explanation of the research was provided to each patient.

Statistical analysis
Th e Statistical Package for Social Science (SPSS) (Illinois, Chicago, USA) was used for data analysis. Mean, median, and SD were used to describe quantitative data. Qualitative data were summarized using frequency and percentage. Th e 2 -test was used to detect associations between qualitative data. A t-test was used for comparison between the middle ear pressure value by tympanometry preoperative and 30 days after pack removal. Th e comparison between preoperative and postoperative ETF tests was performed us ing the 2 -test. Diff erences were considered signifi cant when P value was 0.05 or less.

Results
Th e study was carried out on 30 patients who presented to the otolaryngology outpatient clinic at El-Minia University Hospital complaining of unilateral or bilateral nasal obstruction. All patients were operated on according to the cause of the nasal obstruction as shown in Table 1.

Patients' characteristics
Th ere were 19 male patients (63.3%) and 11 female patients (36.3%). Th e age of the patients ranged from 18 to 60 years, mean age 34 years (Table 2). Th e diff erent preoperative complaints of patients are shown in Table 3.
Th e relation between the laterality of nasal obstruction and preoperative tympanometry and ETF is shown in Table 4, with no signifi cant correlation between the laterality of nasal obstruction and tympanometric type and ETF.
Th e relation between the preoperative nasal obstruction, middle ear pressure, and ETF: Preoperatively, the values of middle ear pressure ranged from −150 to 5 daPa, mean −22 daPa, with a signifi cant association between nasal obstruction and negative middle ear pressure (P < 0.001). Also, 23 patients (76.6%) had poor ETF in at least one ear and seven patients (23.4%) had good ETF, with a signifi cant correlation between nasal obstruction and the results of ETF.
Th e relation between the preoperative type of tympanometry and ETF: 47 (78.3%) ears were type A, 24 of these ears had poor ETF, and 23 ears had good ETF. Th irteen (21.6%) ears were type C, and all had poor ETF.   Th e relation between the tympanometric type preoperatively and at 30 days after removal of nasal packs is shown in Table 5, with a signifi cant improvement in tympanometric type from C to A (P < 0.05).
Th e relation between the middle ear pressure preoperatively and at 30 days after removal of nasal packs is shown in Table 6, with a signifi cant improvement in middle ear pressure (P < 0.05). Th e relation between the ETF preoperatively and at 30 days after the removal of nasal packs is shown in Table 7, with a signifi cant improvement in ETF after the nasal surgery (P < 0.002).
Preoperatively, 28 patients (93.3%) had a sensation of ear fullness. At 30 days after the removal of nasal packs, 20 patients (66.7%) still had a sensation of ear fullness, with signifi cant improvement (P < 0.001).
Six patients (20%) had poor ETF postoperatively, four patients had pan sinusitis with bilateral nasal polyposis and underwent endoscopic sinus surgery, whereas two patients had maxillary sinusitis and marked deviated septum and had endoscopic sinus surgery plus septoplasty. Four of these patients already had poor ETF preoperatively, whereas two patients had good ETF preoperatively.

Discussion
Nasal obstruction has long been associated with middle ear diseases. It has been shown previously that nasal obstruction alters the function of the Eustachian tube and can infl uence middle ear pressure [15].
A negative intratympanic pressure has been considered a sign of impairment in tubal function. Th e middle ear pressure can be assessed behind an intact ear drum by tympanometry, which has been used widely with great success in the diagnosis and follow-up of middle ear disease [16]. Th e aim of this study was to evaluate the eff ect of surgery of nasal obstruction on ETF and middle ear ventilation.
Th e results of our study showed that there was a positive eff ect of nasal surgery for nasal obstruction at 30 days postoperatively. On the basis of the results of this study, there was no signifi cant relation between the laterality of nasal obstruction and the results of middle ear pressure and ETF. Th ese results are similar to that obtained by Salvinelli et al. [16], who did not fi nd a correlation between the side of nasal obstruction and tympanometric or ETF values.
Also, from our results, it was clear that nasal obstruction had an eff ect on middle ear pressure and ETF. Th ese fi ndings are similar to the results obtained by Bonding and Tos [1]. However, these results diff er to some extent from the results obtained by McCurdy [17]. Th ree mechanisms were postulated for Eustachian tube dysfunction after nasal obstruction: fi rst, airfl ow turbulence may lead to deposition of microorganisms and air pollutants in the region of Eustachian tube opining, resulting in tubal epithelium or peritubal infl ammation and mechanical obstruction. Second, tubal mucous viscosity and surface tension may be increased by the drying eff ects of altered air currents, leading to increased tubal opening pressure. Th e third postulated mechanism is that the postnasal mechanical receptors' end on autonomic nerve supply to the Eustachian tube may be stimulated by altered air currents, leading to a refl ex alteration in ETF [18].
Also, the results of our study showed that there is an eff ect of nasal obstruction surgery on the type of tympanometry and middle ear pressure, which became less negative. Th ese results are similar to those reported by Low and Williatt [12]. However, these results diff er from those of Salvinelli et al. [16], who found that there were no signifi cant diff erences between the results of middle ear pressure in the preoperative and postoperative periods up to the 90th day. When we assessed the changes in ETF postoperatively, there was a signifi cant improvement; this was similar to the results of Salvinelli et al. [16].
From the above results, it is clear that chronic nasal obstruction is a frequent cause of Eustachian tube dysfunction that can lead to middle ear hypoventilation, and that surgery for nasal obstruction improves tubal function and middle ear ventilation at least 1 month after the surgical procedure. Our data support the results of Salvinelli et al. [19], who suggested that tympanoplasty and nasal surgery should not be performed at the same time and that middle ear surgery should be carried out at least 3 months after nasal surgery when the anatomy and physiology of nasal, pharyngeal, and tubal mucosa have returned to normal because the Eustachian tube dysfunction and the consequent hypoventilation of middle ear are among the most frequent causes of failure of middle ear surgery. Moreover, failures in middle ear surgery are more likely to occur in patients with nasal function impairment.

Conclusion
Nasal obstruction has a defi nite relationship with ETF. Surgery for nasal obstruction has a favorable eff ect on the middle ear pressure and ETF. Type A tympanogram does not always mean a good ETF, but the patient may have poor ETF with Eustachian tube dysfunction despite type A tympanogram.