Physiology

Paranasal sinus ventilation by humming

The gas nitric oxide (NO) is generated in the human paranasal sinuses and can be measured in nasally exhaled air. During humming, a marked increase in exhaled NO content has been observed. The acoustic phenomenon responsible for this evacuation of NO gas from the sinuses was analyzed. A tube model was constructed with a syringe containing NO gas attached radially. This tube was excited with an air stream modulated by a sine wave. Increased evacuation was observed whenever the syringe was not located at a pressure node of the exciting sine wave. A computer model of the system showed a good matching of observed pressure versus frequency data in the syringe resonator. The results thus suggest that the alternating pressure in the nasal cavity forces the air plug in the ostium of the paranasal sinus resonators to vibrate, thus expelling from the cavity NO gas, which is transported to free air by the exhalatory air stream.

The effect of rhytidectomy on the nasal valve

OBJECTIVES

To determine the effect of deep-plane rhytidectomy on the cross-sectional area of the nasal cavity in the vicinity of the nasal valves and to compare this quantitative measure with patients' subjective assessment of their postoperative nasal airway.

DESIGN

An inception cohort of 17 patients undergoing rhytidectomy (either cheek-lift or face-lift) for facial rejuvenation was evaluated with acoustic rhinometry. Initial measurements were taken approximately 1 week prior to surgery, followed by postoperative measurements at 1 week and again at 1 month (a total of 18 measurements per patient). Patients undergoing simultaneous nasal procedures were excluded. Control subjects consisted of patients undergoing facial plastic procedures other than rhytidectomy or septorhinoplasty (n = 3). The main outcome measure was cross-sectional area of both the internal and external valve regions as determined by acoustic rhinometry. The setting was an ambulatory surgery center at a large academic institution.

RESULTS

Seventy percent of patients (12 of 17) reported subjective improvement of their nasal airway patency following rhytidectomy, whereas no control subjects (0%) reported any such change. Eighty-eight percent of patients (15 of 17) had a substantial increase in the dimension of their internal nasal valve area as measured with acoustic rhinometry at 1 week, with 70% of patients demonstrating increase at 1 month. Fifty-three percent of patients (9 of 17) demonstrated an increase in their external valve area at 1 week, and 59% had a persistent increase as measured at 1 month. No control subjects demonstrated any significant nasal valve area increases at either time. There was no correlation between age or body mass index and the measurement outcomes among participants.

CONCLUSIONS

While there is a statistically significant increase in both the internal and external nasal valve cross-sectional areas at 1 month after rhytidectomy, the permanency of this effect is unknown. In support of these findings, a sizable proportion of patients undergoing rhytidectomy subjectively report an increase in their ability to breathe through their noses, lending credence to a postrhytidectomy melonasal effect.

Rhinosinusitis: review from a dental perspective

Patients often present to their dental providers with reports of posterior maxillary pain. The etiology of their symptoms may be either an acute or chronic situation, and the examining dentist's primary focus is usually to rule out dental pathosis. Rhinosinusitis should be an important consideration on the list of differential diagnoses when evaluating patients with posterior maxillary pain. The American Academy of Otolaryngology standardized the terminology for paranasal sinus infections in 1996 and offered guidelines for evaluation and treatment of sinusitis. This article highlights these guidelines for diagnosing and treating patients with rhinosinusitis. It also includes a review of sinus anatomy and of the special considerations for iatrogenic sinus exposure as well. Dental providers who understand the relationship between the maxillary sinus and the oral structures are better prepared to arrive at an accurate diagnosis. The astute dental provider will ensure a rapid and positive outcome for this group of patients with rhinosinusitis.

3He MR imaging of porcine paranasal sinuses

RATIONALE AND OBJECTIVES

The aim of this study was to test the effectiveness of laser-hyperpolarized helium 3 (3He) as a contrast agent for magnetic resonance (MR) imaging of porcine paranasal sinuses.

MATERIALS AND METHODS

Imaging experiments were conducted on the heads of four 50-kg Yorkshire pigs after open sinus surgery was performed. Paranasal sinus MR images were obtained with laser-polarized 3He gas produced through the spin-exchange method. The gas was delivered into the sinuses through two 14-gauge plastic catheters inserted in the nostrils. The 3He MR images were then compared with spatially correlated proton MR images.

RESULTS

The porcine paranasal sinuses were adequately depicted by MR imaging with hyperpolarized 3He. The signal intensity of the paranasal sinuses on the 3He MR images was related to the size of the opening joining the sinuses to the nasal cavity and was clearly time dependent.

CONCLUSION

Hyperpolarized 3He MR imaging may be particularly useful for identifying the anatomic configuration of the paranasal sinuses, as well as for assessing sinus aeration. Further study of the time-dependence of 3He signal intensity may help increase understanding of gas exchange in the sinuses.

Nocturnal nasal congestion and nasal resistance

OBJECTIVES

To compare total nasal resistance (TNR) in upright and supine positions in patients who did and did not complain of nocturnal (supine) nasal congestion symptoms without daytime (upright) congestion, and to determine what other conditions were associated with nocturnal nasal congestion (NNC) symptoms.

STUDY DESIGN

A prospective study comparing objectively measured nasal airflow in different positions (upright and reclining) with subjective patient symptoms.

METHODS

Subjects completed a questionnaire about nasal symptoms. Anterior rhinomanometry was performed with patients upright, reclined 45 degrees, and supine. TNR in subject subsets was compared using the Student t test.

RESULTS

TNR did not differ between upright patients with (n = 27) and without (n = 20) NNC. Supine TNR (P < .04) and increase in TNR (P < .02) between upright and supine was greater in patients with NNC. Smokers (n = 15, 10 with NNC, 5 without) had greater TNR increases when supine versus nonsmokers (P < .02). Patients with rhinitis symptoms (n = 29, 18 with NNC, 11 without) had greater TNR increases when supine than patients without rhinitis (P < .01). Patients who both smoked and had rhinitis (n = 11, 7 with NNC, 4 without) had a greater supine TNR than patients who smoked or had rhinitis alone (P < .02).

CONCLUSIONS

Some patients without daytime nasal congestion experience NNC. They have a significantly greater TNR increase when supine versus patients without NNC. Smokers and patients with rhinitis, with or without NNC, have a significantly greater TNR increase when supine versus nonsmokers or patients without rhinitis. Smoking cessation and treatment of rhinitis may improve the patients' NNC.

Comparative study of the prevalence of maxillary sinusitis in later Medieval urban and rural populations in northern England

Six hundred sixty-three Medieval individuals from Wharram Percy, a rural settlement in the Yorkshire Wolds, and 1,042 individuals from St. Helen-on-the-Walls, a poor parish in the Medieval city of York, were examined in order to test the hypothesis that maxillary sinusitis would be more prevalent in an urban population due to social and environmental conditions characteristic of an industrialized settlement. The results showed that the individuals from St. Helen-on-the-Walls, living in the urban environment, had a greater prevalence of maxillary sinusitis than the rural population; 39% (106) of the individuals from Wharram Percy had evidence of sinusitis compared to 55% (134) of the individuals from St. Helen-on-the-Walls. It is suggested that this pattern may be attributed to occupation and industrial air pollution in the Medieval city of York.

High nitric oxide production in human paranasal sinuses

Nitric oxide (NO) is present in air derived from the nasal airways. However, the precise origin and physiological role of airway-derived NO are unknown. We report that NO in humans is produced by epithelial cells in the paranasal sinuses and is present in sinus air in very high concentrations, close to the highest permissible atmospheric pollution levels. In immunohistochemical and mRNA in situ hybridization studies we show that an NO synthase most closely resembling the inducible isoform is constitutively expressed apically in sinus epithelium. In contrast, only weak NO synthase activity was found in the epithelium of the nasal cavity. Our findings, together with the well-known bacteriostatic effects of NO, suggest a role for NO in the maintenance of sterility in the human paranasal sinuses.