Patency tests of the maxillary ostium--model experiments

The function of the maxillary ostia (phi 0.22-4.7 mm) has been evaluated in experiments on a nose-sinus model with variable sinusal volumes. A piston-pump producing to-and-fro volumes of 467 cm3 of air per revolution was used at a speed of 10 and 20 revolutions per minute (rpm). Three different techniques were used: simultaneous pressure recording in the sinus and the nose (Method I); simultaneous recording of the differential pressure between nose and sinus and the air-flow through the ostium (Method II); recording of the pressure rise inside the sinus upon the application of a constant artificial air-flow of 16,7 cm3 . s-1 or 2.0 cm3 . s-1 (Method III). All variables were recorded on an ink-jet recorder and onto tape when using methods I and II for later analysis on an x-y recorder. A pressure relationship of 1 : 1 was found between nose and sinus, independently of ostial diameters, sinusal volumes and piston-pump rates. The first method did not permit an isolated determination of the ostial function as the pressure values recorded are affected by ostial diameters, sinusal volumes and piston-pump rates. The pressure-flow relationship recorded with the second method was found to be dependent only on the ostial diameters. Hysteresis was observed at ostial diameters less than or equal to 1.63 mm. This is due to ostial diameter, sinusal volume and the rate of the nasal pressure changes. This method is suitable for an isolated determination of the ostial resistance, from which the equivalent ostial diameter can be calculated. With the third method using static air-flows and pressures the results are independent of the sinusal volume. This method is suitable for estimation of the ostial airway resistance and the equivalent ostial diameter. A striking similarity was observed between the results obtained with the last two methods in estimating equivalent ostial diameters.     

Effects of phenylpropanolamine on ostial and nasal patency in patients treated for chronic maxillary sinusitis

Ostial and nasal patency were measured in different body positions and after phenylpropanolamine (Ppa) treatment in 12 patients earlier treated for chronic unilateral maxillary sinusitis of varying severity. Six of the sinuses were of normal appearance on sinoscopy. Phenylpropanolamine in a single dose of 100 mg was found to increase the equivalent ostial diameter significantly in the sitting and recumbent positions. The drug also reduced the nasal airway resistance. The Ppa effect might be of benefit in patients treated for chronic maxillary sinusitis.     

Nasal obstruction: an alternative to ostiomeatal complex dysfunction in sinus disease

OBJECTIVES: Ostial patency is thought to be essential to the function of the maxillary sinus. Ostiomeatal complex dysfunction has been implicated as a major factor in the pathogenesis of sinus disease. However, recent work in our laboratory has indicated that other factors may also contribute to this process. The objective of this study was to determine the effect of nasal obstruction in maxillary sinus gas composition, independent of its effect on ostial ventilation. STUDY DESIGN: Prospective controlled animal study. METHOD: Independent models of nasal obstruction and ostial occlusion in contralateral sinuses were established. Ipsilateral models of nasal obstruction and ostial occlusion were also created. Gas samples from each of the manipulated sinuses were analyzed on a gas chromatogram and compared. RESULTS: Results revealed a dramatic and highly significant increase in antral carbon dioxide (CO2) concentrations in the sinuses ipsilateral to either an occluded ostium or an obstructed nostril, compared with the controls. These effects on CO2 concentrations were additive when ipsilateral nasal obstruction and ostial occlusion were created. Furthermore, the effect of nasal obstruction in modulation of antral CO2 levels was found to be beyond its effect on hypoventilation of the sinus and to be independent of ostial functional status. CONCLUSIONS: We have established independent models of nasal obstruction and ostial occlusion in the same animal. Our findings suggest that ostiomeatal complex dysfunction might not be the sole underlying factor in the pathogenesis of sinus disease in all individuals. Integrity of nasal airflow seems to have a significant effect on the maintenance of the aerobic antral environment, essential to the maintenance of normal sinus function. Modulation of maxillary sinus gas composition by nasal airflow, independent of ostial patency, may be explained by the possible presence of flow-sensitive receptors in the upper respiratory tract mucosa. Work to identify such receptors is currently in progress.     

Pressure measurements in the normal and occluded rabbit maxillary sinus

Occlusion of the maxillary ostium is considered to be a key factor in the pathogenesis of maxillary sinusitis. In this study, the authors determined the effect of ostial occlusion on pressure in the rabbit maxillary sinus which, like most humans, has only one ostium. We compared pressures in the normal and occluded maxillary sinus and the nasal cavity during spontaneous breathing in anesthetized adult animals. Serial pressure measurements were obtained from sinuses with patent ostia in nasal-breathing rabbits and with occluded ostia in both nasal-breathing and tracheotomized animals. Sinuses with patent ostia showed pressure curves synchronous with the respiratory cycle. Inspiratory and expiratory pressures in the nasal cavity and the sinus were isobaric. Sinuses with occluded ostia initially developed a positive pressure followed by a negative pressure that reached a subatmospheric plateau of-28.2 ± 7.3 mm H₂O (mean ± standard deviation [SD]) within 20 to 50 minutes. This is the first quantitative study of sinus pressures using the rabbit as an animal model. The findings may contribute to a better understanding of the role of ostial occlusion in the pathogenesis of maxillary sinusitis in humans.     

Effects of long-term induced ostial obstruction in the rabbit maxillary sinus

One of the widely proposed theories for mucocele formation is sinus ostial obstruction. Accordingly, this study was undertaken to investigate the long-term effects of ostial obstruction in the rabbit maxillary sinus and its potential role in the pathogenesis of mucoceles. Maxillary sinus ostial obstruction was induced on one side in eight Pasteurella-free White New Zealand rabbits using Histoacryl. The rabbits were housed in a Pasteurella-free zone for 24 weeks. At re-exploration, only three of the eight maxillary sinuses where ostial obstruction was induced showed pressure recording consistent with ostial obstruction. Mucociliary clearance activity was assessed using India ink. Swabs for culture were taken from the infected maxillary sinuses. Mucosal specimens for histopathological examination were harvested from one of the maxillary sinuses with obstructed ostium as well as from another sinus with nonobstructed ostium. The three maxillary sinuses with obstructed ostia showed gross evidence of infection and deranged mucociliary clearance, but no mucocele formation. Based on the findings of this study it is concluded that long-term ostial obstruction indeed plays a role in the pathogenesis of chronic sinusitis, but it did not induce mucocele formation in the rabbit maxillary sinus.     

Ostial and nasal patency in chronic maxillary sinusitis. A long-term post-treatment study

In a long-term follow-up study (mean 3.5 years) after treatment of chronic maxillary sinusitis of either rhinogenous or dental origin, 72 sinuses in 66 patients were examined with respect to maxillo-ostial and nasal resistance. In sinusitis of rhinogenous etiology, the mean equivalent ostial diameter was pathologically narrowed (0.89 mm, in patients treated conservatively) whereas it was normal (2.51 mm) in sinusitis of dental etiology (dental treatment in combination with local sinus surgery). In the former group, all sinuses were diseased, compared with 3 out of 23 in the dental group. In order to distinguish between functional and organic ostial stenosis, the patients were also tested after physical exercise. The functional ostial diameter in healthy sinuses was significantly increased in contrast to the diseased sinuses. In one patient the narrow ostium was due to mucosal swelling only, but in the other cases was caused mainly by an organic stenosis. In sinusitis of rhinogenous etiology, a pathologically increased nasal resistance was found in 14.3%, while the corresponding figure in the dental group was 4.3%. Improved sinusal and nasal ventilation, achieved either pharmacologically or, preferably by surgical intervention, seems necessary for successful treatment of chronic maxillary sinusitis.     

The influence of the size of the maxillary sinus ostium on the nasal and sinus nitric oxide levels

BACKGROUND: Nitric oxide (NO) is produced in significant quantities in the nasal sinuses and is thought to have a beneficial effect on the mucociliary transport of the sinuses and nose and to have significant antibacterial properties that contribute to the health of the sinuses. Recently, the concept of "mini-functional endoscopic sinus surgery" has been introduced where the uncinate is removed without enlargement of the maxillary ostium. Although no scientific evidence has been published, enlargement of the ostium is thought to possibly disrupt the mucociliary pathway and decrease the concentration of NO in the nose and sinuses. The aim of this study was to establish the effect of enlargement of the maxillary ostium on sinus and nasal NO. METHODS: Twenty-nine patients who were post-endoscopic sinus surgery were included with 52 who were maxillary sinus ostia cannulated. There were 22 large maxillary sinus ostia and 30 small ostia. Smoking, allergy status, and topical steroid use were recorded. NO levels were measured in the nose and maxillary sinus after decongestion with patients mouth breathing and breath holding. RESULTS: This study shows that enlargement of the maxillary sinus ostium above its normal size (20 mm2) produces a significant decrease in both the maxillary sinus and the nasal cavity NO levels. In addition, the size of the ostium showed a significant correlation to the sinus NO level. Use of topical nasal steroid sprays and topical decongestants were shown to effect NO levels in the sinuses and nasal cavity. The lowered levels of NO were found irrespective of the technique of measurement of the NO. CONCLUSIONS: The effect of this lowered NO level on the susceptibility of the maxillary sinuses to recurrent infection is yet to be determined.     

鼻窦内窥镜手术处理病变中鼻甲的意义

目的：探讨功能性鼻窦内窥镜于术（ＦＥＳＳ）中处理病变中鼻甲的临床意义。方法：按照成人中鼻甲解剖学标准,在３２例鼻窦炎、鼻息肉患者ＦＥＳＳ中,对病变中鼻甲进行适当处理,并于术后对中鼻甲形态恢复、筛窦术腔及上凳窦窦中开放率进行随访观察。结果：术后６个月中鼻甲形态恢复正常２４例（７５％）,发生粘连８例（２５％）,其中术腔闭塞２例（６．３５％）;上颌窦窦口开放良好２５例（７８．１％）,狭窄６例（１８．８％     

Role of the maxillary sinus as a resonant cavity]

Patients with a paranasal disorder often manifest voice change. Yet, computer simulation of these nasal sounds is difficult using a nasal tract model without any branching cavity. In other words, acoustic property of the nasal tract is influenced by a coupling with the paranasal sinuses. If the transfer function of the sinus acts as a Helmholtz resonator, the resonance frequency, or "zero" point, of the sinus would be present on the acoustic spectrum of the nasal cavity. This study was designed to prove the validity of this hypothesis. The sweep tone was given from the subjects' epipharyngeal space. The tone passed through their nasal space and radiated from the anterior nostrils. In 13 cases without nasal or paranasal disorders, the tones obtained at the nostrils were analyzed with Fast Fourier Transformation (FFT) and were compared between two conditions of the ostia of the maxillary sinuses, obstructed and opened with epinephrine. The resonance frequencies of the maxillary sinuses ranged from 1 to 2 kHz and varied considerably among individuals. This variation may be due to a difference in the maxillary sinus volume and in the diameter and length of the natural maxillary ostium. In past reports, in which the resonance frequency of the sinus was measured using a compound model or computed simulation, the maxillary sinus resonated below 1 kHz. In these reports the ostium of the maxillary sinus was regarded as a straight pipe. However, the examination of 29 cadavers revealed that the radius of the ostium differs according to its depth. The radius in the depth halfway from the edge was narrower than that of the edge. The way of evaluating a shape of the ostium is different between the present and the past studies, thus possibly resulted in discrepancy of the resonance frequency.     

Density of epithelial cells in the normal human nose and the paranasal sinus mucosa. A scanning electron microscopic study

214 biopsies of mucosa from various sites of the nose and paranasal sinuses were obtained post-mortem and examined using the scanning electron microscope. The density of ciliated cells was increased in the nasal cavity, in the antero-posterior direction. In paranasal sinuses the density of these cells was high, except near the ostium of the maxillary sinus, where the density was decreased by half. Non-ciliated epithelial cells were found in relatively few areas: anterior aspect of the middle and lower turbinates, anterior septum. However, no uniform distribution of these cells was present. The density of goblet cells was significantly lower in the paranasal sinuses as compared to the nasal cavity, with the highest density being found near the ostium of the maxillary sinus.     

The patency of the maxillary ostium in relation to body posture.

Eleven subjects were investigated concerning the effect of postural changes on the functional size of the maxillary ostium. The ostial size expressed as the percentage of the initial value decreased only slightly when the body position was altered from 90 degrees (sitting) to 30 degrees, while the decrease between 30 degrees and 0 degrees (lying) was more pronounced. A cuff around the neck inflated to 25 mmHg gave a decrease corresponding to a value of 20 degrees body position. Insufficient ventilation of the paranasal sinuses when lying down may result, especially in cases already having small ostia in the sitting position.     

鼻内窥镜术上颌窦自然开口的处理

目的探讨内窥镜鼻窦手术治疗慢性鼻窦炎、鼻息肉的上颌窦中鼻道开口的重要性及处理方法。方法配对研究５６例双侧鼻窦炎、鼻息肉患者，比较同一患者术中扩大或不扩大上颌窦自然开口的术后情况。结果窦口的开放率在不扩大和扩大上颌窦自然开口的术侧中分别为９２．９％和８０．４％（随访６个月时）。回顾性观察５１例施ＣａｌｄｗｅｌＬｕｃ术的患者，下鼻道造口的术后开放率仅为４０．６％。分析３８张单侧鼻窦炎或鼻息肉的鼻窦ＣＴ片，测量对照侧与病变侧的上颌窦口膜样部的上下径和前后径，差异无显著性。病变侧上颌窦口周围的中鼻甲气化、增生及钩突偏曲、筛泡骨性增生等解剖结构异常的发生率明显高于对照侧（Ｐ＜０．０５）。结论鼻内窥镜下处理上颌窦自然开口的关键是窦口周围的解剖异常因素。     

鼻内窥镜术上颌窦自然开口的处理

探讨内窥镜鼻窦手术治疗慢性鼻窦炎，鼻息肉的上颌窦中鼻道开口的重要性及处理方法。方法 配对研究５６例双侧鼻窦炎，鼻息肉患者，比较同一患者术中扩大或不扩大上颌窦自然开口的术后情况。结果 窦口的开放率在不扩大和扩大上颌窦自然开口的术侧中分分别为９２．９％和８０．４％。     

Effects of anatomical variations of the nasal cavity on acoustic rhinometry measurements: a model study

BACKGROUND: The goal of this study was to assess how anatomic variations of the nasal cavity affect the accuracy of acoustic rhinometry (AR) measurements. METHODS: A cast model of a human nasal cavity was used to investigate the effects of the nasal valve and paranasal sinuses on AR measurements. A luminal impression of a cadaver nasal cavity was made, and a cast model was created from this impression. To simulate the nasal valve, inserts of varying inner diameter were placed in the model nasal passage. To simulate the paranasal sinuses, side branches with varying neck diameters and cavity volumes were attached to the model. RESULTS: The AR measurements of the anterior nasal passage were reasonably precise when the passage area of the insert was within the normal range. When the passage area of the insert was reduced, AR measurements significantly underestimated the cross-sectional areas beyond the insert. The volume of the paranasal sinus had limited effect on AR measurements when the sinus ostium was small. However, when the ostium size was large, increasing the volume of the sinus led to significant overestimation of AR-derived areas beyond the ostium. CONCLUSION: The pathologies that narrow the anterior nasal passage result in the most significant AR error by causing area underestimation beyond the constriction. It also appears that increased paranasal sinus volume causes overestimation of areas posterior to the sinus ostium when the ostium size is large. If these physical effects are not considered, the results obtained during clinical examination with AR may be misinterpreted.     

Chronic bacterial rhinosinusitis: description of a mouse model

OBJECTIVES: To survey normal murine sinonasal anatomy and to create a mouse model for chronic bacterial rhinosinusitis. DESIGN: Anatomic, histologic, and pathophysiologic study displaying normal murine sinonasal anatomy and surgically created unilateral sinonasal inflammation. SUBJECTS: Twenty-one 6-week-old, male C57BL/6 mice. INTERVENTIONS: Animals that underwent unilateral maxillary sinus ostial obstruction using Merocel nasal packing, animals with unilateral Bacteroides fragilis inoculation alone, and animals with both ostial obstruction and bacterial inoculation were examined at 4 weeks for histologic evidence of chronic sinonasal inflammation. Experimental interventions were compared with contralateral control sinuses within each animal and with normal and sham-operated controls. RESULTS: Normal mouse paranasal sinuses include maxillary sinuses, ethmoid air cells, and respiratory-type epithelium. In experimental animals, the lateral maxillary sinus wall, nasal septum, and superior turbinelle of the maxillary sinus were examined histologically. Epithelial thickening and disarray, goblet cell hyperplasia, inflammatory infiltrates, and sinonasal fibrosis were present in the experimental sinuses of animals packed with Merocel alone or Merocel with bacterial inoculation. Changes seen with Merocel and bacteria were more dramatic than those with Merocel alone. Sham-operated controls and sinuses inoculated with bacteria alone did not differ significantly from the sinuses of normal animals. CONCLUSION: Unilateral maxillary sinus ostial obstruction using Merocel nasal packing along with B fragilis inoculation results in a persistent, localized bacterial rhinosinusitis in mice.     

Ostium resistance in acute maxillary and frontal sinusitis.

Ostium function tests were performed in 18 normal maxillary and 6 normal frontal sinuses. Further 57 patients with acute maxillary and 16 patients with acute frontal sinusitis were followed using sinumanometry until resolution of infection occured. After initial obstruction of the ostium, resistance decreased exponentially until complete decongestion. Respiratory pressure changes in the sinus during forced nasal breathing are a positive sign for healing of sinusitis. The amplitude of these fluctuations should be documented during each lavage and facilitates indication for drainage procedures.     

上颌窦自然开口开放方式对上颌窦纤毛传输途径的影响

目的 对比全面开放和保留上颌窦下缘两种上颌窦自然开口开放方式对手术后上颌窦纤毛传输途径的影响,探讨内镜鼻窦手术(endoscopic sinus surgery,ESS)中开放上颌窦自然开口的恰当位置.方法设立3个观察组,观察示踪剂从上颌窦内向鼻腔的传出途径的差别.①正常对照组30例;②实验A组30例:ESS手术中全面开放和扩大上颌窦自然开口;③实验B组30例:ESS手术中采用上颌窦自然开口前缘和(或)后缘扩大、完整保留下缘.两个实验组均为慢性鼻-鼻窦炎经鼻内镜手术后12个月以上、窦口开放良好的病例.结果 ①正常对照组上颌窦内示踪剂均从自然开口下缘引流出,并直接进入中鼻道,其中下缘后份是核心区域;②全面扩大上颌窦自然开口组(实验A组)30例中,从下缘引流者4例(13.3%),从后缘和(或)上缘弥散进入筛窦者17例(56.7%),示踪剂堆积于上颌窦内和(或)在窦内呈旋转性传输运动,但不能引流出上颌窦者9例(30.0%);③保留上领窦自然开口下缘组(实验B组),全部通过下缘直接进入中鼻道(30/30,100%),无改变引流途径的病例.结论 ①上颌窦自然开口下缘是上颌窦纤毛传输的主要途径;②保留下缘的上颌窦自然开口扩大术后,上颌窦纤毛传输途径与正常人无差别;③全面开放上颌窦自然开口后,上颌窦纤毛传输途径发生改变,只有少数从自然开口下缘直接进入中鼻道,多数从上缘和(或)后缘弥散进入筛窦,部分积滞于上颌窦内难以排出.     

Studies of the effect of peroral fenylpropanolamin on the functional size of the human maxillary ostium

The effect of peroral fenylpropanolamin on the functional size of the human maxillary ostium was studied in 20 patients suffering from acute rhino-sinusitis. The size of the maxillary ostium was measured by a manometric procedure over a 2-hour period. During the introduction of a known airflow into the sinus for a short while, the pressure increase was compared with a nomogram obtained by model experiments. The introduction of the cannulas into the maxillary sinus caused a swelling of the mucosa in the ostium in the placebo group and initially also in the group receiving fenylpropanolamin, but, after 60 minutes, the latter group had a mean functional ostial size greater than the initial one. These differences were not statistically significant. This seems to be the first objective study of the size of the ostia in the human paranasal sinuses during treatment with a peroral decongestant.     

Reevaluation of maxillary sinus surgery: experimental study in rabbits

Functional endoscopic sinus surgery concentrates primarily on the removal of ostiomeatal complex disease. When required, maxillary sinus ostioplasty is performed. However, surgical widening of a sinus ostium is contrary to common precepts. A study therefore was performed to reevaluate the effects of antrostomies and of intrasinus mucosal removal. Widening of the natural ostium, a separate antrostomy at some distance from the ostium, or radical mucosal removal was performed on 30 rabbits. Fifteen sinuses were used as controls. After 6 to 8 weeks the status of the sinus mucosa and mucociliary clearance was studied. The study confirmed that mucociliary clearance continued toward the natural ostium following inferior antrostomy. Following widening of the natural ostium, mucociliary clearance through the ostium redeveloped in 11 of 18 sinuses but was typically imperfect. There were no cases of ostial closure; however, the incidence of infection was significantly higher in all three experimental groups than in the control group.     

Effects of oxymetazoline on the ventilation of paranasal sinuses in healthy subjects

BACKGROUND: Impairment of sinus ostial function is considered an important factor in the pathophysiology of sinus disease. The use of the decongestants such as alpha2-agonists is thought to improve sinus ostial function. Previous studies have shown an effect of alpha2-agonists on maxillary sinus ostial function only when administered in nasal bellows, but not as a nasal spray or nasal drops. The effect of decongestants on ventilation of the frontal and posterior ethmoidal and sphenoidal sinuses has not been studied to date. METHODS: In this study, the 133-xenon washout method was used to determine ventilation for all paranasal sinuses before and after administration of oxymetazoline as nasal drops in eight subjects and from nasal bellows in nine healthy subjects. RESULTS: No significant effect of oxymetazoline on sinus ventilation was seen in either group. CONCLUSIONS: The results indicate that alpha2-agonists do not have any effect on sinus ventilation in healthy subjects. However, one cannot exclude that decongestants improve sinus ventilation in patients suffering from sinus disease and this requires further studies.