Patency of the maxillary sinus ostium in healthy individuals

[Surgical anatomy of the maxillary sinus]

BACKGROUND

Improved understanding of the microanatomy of the paranasal sinuses, including its individual variations, makes a substantial contribution to current progress in endonasal endoscopic microsurgery. Microanatomy of the sinuses is an active field of present scientific investitations.

MATERIALS AND METHODS

A comprehensive review on microanatomy of the maxillary sinus is presented from the perspective of contemporary endonasal endoscopic microsurgery.

RESULTS

The range of variation of the individual microanatomy of all sections of the maxillary sinus is presented, in particular to minimize secondary sugical tissue trauma, to avoid complications (e.g. on orbital tissues) and as a basis for the prelacrimal access to the maxillary sinus.

CONCLUSION

Improved understanding of the range of microanatomical variations reduced the burden on the patient while opimizing the effectiveness of the necessary surgical manipulations.

Use of negative air pressure by nasal suction during maxillary sinus floor lift: audit of 13 consecutive sinus grafts

A common and serious intraoperative complication of sinus floor lift is perforation of the sinus lining. Several strategies to prevent or treat it have had varying results. We report the results of an audit of 13 consecutive sinus grafts in 11 patients in which nasal suction was used to facilitate raising the sinus lining, and to reduce the risk of perforation.

Factors influencing 133-xenon washout in a nose-sinus model

The 133-xenon washout technique is a non-invasive method for the evaluation of ventilation of the paranasal sinuses. The half-time of 133-xenon washout (T(1/2)) is considered to reflect sinus ostial function and sinus ventilation. However, it is not known how morphological and physiological factors affect the washout from the paranasal sinuses. The aim of the present study was to evaluate how sinus volume, ostial diameter and nasal ventilation influence 133-xenon washout in a nose-sinus model. This is important for the interpretation of measurements of 133-xenon washout from paranasal sinuses in healthy subjects and in subjects with sinus disease. The 133-xenon washout was measured with a scintillation camera. The statistical analysis of the results showed that the logarithm (to the base 10) of the half-time of 133-xenon washout is linearly related to the ostial diameter, the sinus volume and the nasal ventilation in the model. In a multiple linear regression model, the most important factor contributing to 133-xenon washout was found to be the ostial diameter, which explained 76% of the variation in log T(1/2). In the same statistical model the sinus volume explained 7.5% and the ventilation 5.3% of the variation in log T(1/2). Calculations of the functional ostial diameter in healthy subjects were made, based on the results of the model study. The mean functional ostial diameter was found to be 3.5 mm (range 0.5-7.5 mm). The results obtained with the present model experiments may be of importance for the correct interpretation of the results of measurements of 133-xenon washout in healthy subjects and patients.

Methods for measurement/evaluation of the maxillary and frontal sinus ostial function

Several test methods for evaluation of the maxillary and frontal sinus ostial function have been described. The test methods can be divided up as follows. Invasive methods: Measurements during spontaneous breathing and measurements during artificial pressure application. Non-invasive methods: Methods with pure stable xenon and xenon133. The most physiological invasive method is measurement during spontaneous nasal breathing and simultaneous recording of the pressure difference over the ostium and air flow through the ostium. Hereby, the ostial resistance can be calculated and the equivalent ostial diameter be estimated. Ostial equivalent diameters up to 2.5 mm can be calculated. By measurement of the pressure difference between the sinus and nose during application of a constant air flow of 1 liter per minute into the sinus, the pressure increase corresponds to the equivalent ostial diameter. Ostial equivalent diameters up to 4.7 mm can be estimated. Non-invasive methods with stable xenon and xenon133 permit an overall evaluation of the ventilation of the paranasal sinuses. However, these methods will only give indirect information about the ostial condition. The non-invasive methods have to be compared with the invasive methods in order to find out if the wash out curves correspond to the equivalent ostial diameter.

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.

Effects of phenylpropanolamine on ostial and nasal airway resistance in healthy individuals

Ostial airway resistance (OAR) of 11 maxillary ostia and the airway resistance of the nasal cavity (NAR) in 6 healthy persons were tested before and after administration of phenylpropanolamine (Ppa) and placebo. The effects of physical exercise were also tested. After logarithmic transformation, the resistance values showed a normal distribution. Significant effects on the ostial resistance in relation to initial values were found after Ppa medication. The effect was more pronounced in recumbency than in the sitting position. Physical exercise also gave a significant reduction of ostial resistance while placebo treatment was without effect. On comparison of the Ppa- and placebo-groups in an extended statistical analysis, more striking differences were found both for OAR and NAR. In this model study, Ppa thus showed effects in healthy individuals.

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.