Influence of nasal structure on the distribution of airflow in nasal cavity

STATEMENT OF PROBLEM: Numerical simulation of the nasal cavity is essential in order to understand the relationship between nasal structure and airflow characteristics. Since the structure of the nasal cavity varies significantly, the relationship between nasal structure and airflow characteristics will be investigated by numerical simulation of airflow in twenty-four nasal models in this paper. METHODS OF STUDY: Twenty-four three-dimensional models of the nasal cavity structure have been reconstructed on the basis of Computed Tomography medical images collected from twenty-four healthy volunteers. Modification of the turbinate has been applied to one of these models in order to simulate an operation. The results from this variant model have been compared with the original model. The numerical simulation for the airflow in the nasal cavity was performed by the finite element method. MAIN RESULTS: Pressure drop and the airflow distribution in nasal models are presented quantitatively in flow field. Main airflow will pass through the common nasal meatus. The nasal airway resistance in the region of nasal valve and nasal vestibule (flow limiting structure) accounts for 52.6%-78.3% of total nasal airway resistance. PRINCIPAL CONCLUSIONS: The numerical results show that differences in patients' nasal cavity structure may lead to different airflow distributions. Changes of nasal structure lead to variation of airflow in both sides of the nasal cavity as well as airflow redistribution in each side of the nasal cavity.     

Comparison of feline nasal cavity dimensions measured by acoustic rhinometry and nasal casts

BACKGROUND: The goal of this study was to evaluate the relationship between feline nasal cavity geometry determined in vivo by acoustic rhinometry (AR(in vivo)) and by nasal cavity casts. Cast cross-sectional areas were measured by acoustic rhinometry (AR(cast)), a fluid-displacement method (FDM), and slicing. A volume comparison between AR(in vivo) and AR(cast) was studied in cats with varying degrees of nasal obstruction after application of phenylpropanolamine, saline, or compound 48/80. METHOD: After measurements of AR(in vivo), impression material was injected into the nasal cavity to produce casts. Subsequently, the cross-sectional areas of the nasal impressions were measured by AR(cast) and FDM using ethanol. All casts were weighed to determine exact volume. Six casts also were sliced into segments of equal thickness for determination of cross-sectional area. RESULTS: Cast volume determined by AR(cast) was consistent with results obtained using FDM and weight. Volumes of the first 3 cm determined by AR(in vivo) ranged between 78 +/- 9% of cast volumes determined by AR(cast) for decongested cavities and 16 +/- 15% for congested cavities. CONCLUSION: AR(in vivo) does not reflect cast geometry, probably because of (1) underestimation by AR because of methodological problems caused by the cavity geometry, (2) deformation of compliant structures within the nasal passageways resulting from the casting procedure, and/or (3) the casting material reaches parts of the nasal cavity not accessible to sound, e.g., sinuses or recesses. Nevertheless, this study does not preclude the use of AR as a sensitive method suited to evaluate relative changes in nasal volume caused by experimental challenges of the nasal mucosa. Compared with AR(in vivo), casts still may be of use but it is less sensitive to measure relative changes after experimental challenge.     

Angiosarcoma of the nasal cavity.

Angiosarcoma of the nasal cavity is extremely rare. We present a case of angiosarcoma of the nasal cavity in an eight-year-old boy. He was treated with medial maxillectomy via lateral rhinotomy. The histological diagnosis was confirmed by immunohistological stain with Factor VIII-like antigen. Magnetic resonance imaging (MRI) was useful in determining the extent of the tumour.     

Changes in nasal cavity dimensions in children and adults by gender and age

OBJECTIVE: The aim of the study was to establish the dynamics of changes in the intranasal spaces of children and adults by gender and age. MATERIALS AND METHODS: Each side of the nasal cavity was evaluated separately in 366 healthy subjects 9 to 74 years old. The following acoustic rhinometry parameters were analyzed: 1) I-C, distance between the isthmus nasi (I) and the head of the inferior turbinate (C); 2) CA-I, cross-sectional area at the isthmus nasi; 3) CA-C, at the head of the inferior turbinate; and 4) CA-F, the highest point on the rhinometric curve between points I and C. RESULTS: Before age 11 years, the intranasal spaces were slightly larger in girls than in boys. After age 11 years the nasal parameters were larger in boys than in girls. The growth rates before age 17 years were as follows: I-C: 0.073 cm/yr, 0.135 cm/yr, CA-F: 0.055 cm2/yr, 0.133 cm2/yr (P < .00001), and CA-C: 0.010 cm2/yr, 0.034 cm2/yr (P < .02) in girls and boys, respectively. In subjects older than 16 years, the mean values of I-C were 1.707 cm, 1.934 cm (P < .0001), and of CA-C, 0.493 cm2, 0.611 cm2 (P < .0001) in women and men, respectively, and changed slightly over the year. CONCLUSIONS: The parameters of intranasal spaces depend on age and gender. The dynamics of the changes is greater in boys than in girls and usually the growth is completed by the age of 16. After this age, nasal cavities are bigger in men than in women.     

Influence of long-term airflow deprivation on the dimensions of the nasal cavity: a study of laryngectomy patients using acoustic rhinometry

We conducted a prospective study to investigate the long-term effect of nasal airflow deprivation on nasal dimensions after total laryngectomy. We evaluated 48 patients who had an initial diagnosis of laryngeal cancer; 6 were disqualified during follow-up, leaving us with data on 42 patients for our final analysis. Acoustic rhinometry was used to measure the minimum cross-sectional area (MCSA) and the volume of the nasal cavity on both the left and right sides before and after laryngectomy. In addition, patients underwent endoscopic nasal examinations and answered questionnaires pre- and postoperatively. At both the 1- and 2-year follow-ups, the mean MCSAs and the mean nasal volumes of both the left and right nostrils were significantly smaller than the preoperative values (p < 0.001). The endoscopic examinations revealed only a mild deterioration in the appearance of the nasal mucosa over the long term. Questionnaire responses obtained at the 2-year follow-up visit revealed that all 42 evaluable patients were experiencing a moderate degree of nasal obstruction while inhaling through the nose. Our data indicate that the dimensions of the nasal cavity appear to be substantially and permanently reduced after total laryngectomy. Our study had two important advantages over other similar studies. First, because ours was a prospective study, we were able to obtain preoperative data and use it to make postoperative comparisons of the same patients rather than using healthy controls as comparators. Second, we used acoustic rhinometry, while most other studies relied on anterior rhinoscopy or rhinomanometry, which are inferior methods ofmaking the evaluations in question. We believe that our findings represent a substantial contribution to our knowledge of the physiologic and functional alterations of the nasal cavity that occur as a result of a complete cessation of nasal airflow.     

Basaloid-squamous carcinoma of the nasal cavity.

Basaloid-squamous carcinoma is a recently characterized, aggressive tumour occurring in the hypopharynx, larynx and base of tongue. We report a unique case involving the nasal cavity of a patient with a history of radiation therapy for nasopharyngeal carcinoma, raising the possibility that basaloid-squamous carcinoma can be radiation-associated.     

Malignant oncocytoma of the nasal cavity.

Malignant oncocytoma of the major salivary glands is uncommon. Those of the endocrine, minor salivary and mucous glands are certainly rare. A case of a slowly-growing, low-grade malignant oncocytoma of the nasal cavity in a 50-year-old male, with no lymph node or distant metastases or local invasion of vital adjacent structures, and treated with combined radiotherapy and radical surgery, has been presented. The literature has been briefly reviewed, and the histological types; the electro-microscopic, histochemical and clinical pictures; and the outlines of treatment of oncocytomas have been discussed.     

Neurofibrosarcoma in the nasal cavity

A nine month old male child presented with a swelling protruding from the right nasal cavity for two months. Other symptoms were mild breathlessness during suckling and blood stained nasal discharge. CT Scan sshowed a mass arising from the lasteral wall of the right nasal cavity with mild erosion of the adjacent bones. The tumor was excised with wide margin through a lateral rhinotomy approach under general anaesthesia. In histopathological examination it was found to be a low grade neurofibrosarcoma. The child recovered well and is free from any recurrence till the time of reporting.     

Nitric oxide accumulation in the nonventilated nasal cavity.

BACKGROUND: Nasal nitric oxide is present in high concentrations in the upper airway relative to the lower respiratory tract. OBJECTIVE: To explore the rate of nitric oxide accumulation in the nonventilated nasal cavity. METHODS: In 9 healthy subjects previously trained to close the soft palate, steady-state plateau nitric oxide levels were recorded while air was aspirated through the nasal airway in series at a constant flow rate. Nitric oxide was then allowed to accumulate in the nasal cavity by occluding both nares and keeping the velum closed. After varying occlusion times, peak nitric oxide levels and a second plateau were ascertained. RESULTS: While the subjects aspirated air at a constant flow, there was a slow rise to a first nitric oxide plateau. On opening to the analyzer after the accumulation period, the peak nitric oxide level was several times higher than the initial plateau (range, 2810-19008 ppb) and then slowly returned to previous plateau levels. There was no significant difference between initial and second plateau nitric oxide levels for any period. The accumulated nitric oxide peak increased in direct proportion to the accumulation time (P<.001). CONCLUSIONS: Nitric oxide concentrations accumulate in the nonventilated nasal cavity in proportion to the time of nonventilation. Peak nasal nitric oxide values after accumulation are similar to published sinus nitric oxide measurements obtained by direct puncture. These results suggest an important alternative source of nitric oxide in humans.     

Leiomyoma of the nasal cavity

A case of rare leiomyoma of the nasal cavity is reported. The pathological and clinical characteristics of this tumour are discussed.     

Schwannoma of the nasal cavity

Schwannomas are benign peripheral nerve sheath tumors that occur throughout the body. They may present as either solitary or multiple masses. They rarely occur in the nasal cavity. The diagnosis is often made only after histologic examination. Because these lesions are radioresistant, the preferred treatment is complete surgical excision. We present a new case of a schwannoma of the nasal cavity.     

Haemangiopericytoma of the nasal cavity

This rare tumour arises from proliferation of pericytes which invest capillary endothelium. It has tendency to develop recurrence and metastases. Stout (1912) reported first case of haemangiopericytoma. Since then only 23 cases have been reported in the literature. We present one case of haemangiopericytoma of the nasal cavity.     

CT of the nasal cavity

CT demonstrates nasal anatomy extremely well. The intimate relationship of the nasal cavity to the cerebral, orbital, paranasal sinus, nasopharyngeal, and oral tissues is noted. Examples of benign and malignant neoplasms, inflammatory processes, including intrinsic and extrinsic mass lesions are utilized to demonstrate the value of CT in assessing the nasal cavity in conjunction with its surrounding tissues. Congenital and traumatic lesions also are demonstrated to the same advantage.     

Glomangiomyoma of the nasal cavity

Glomus tumor is a rare neoplasm that typically occurs in soft tissue of the extremity, particularly the subungual region of the finger tip. It rarely occurs in the nasal septum. Glomangiomyoma is a rare histologic variant of glomus tumor. The authors describe a case of glomangiomyoma of the nasal septum that presented as nasal obstruction. The histologic, immunohistochemical, and electronmicroscopic findings are described. The otolaryngologist and surgical pathologist should be aware of such an entity, and should not confuse it with the totally unrelated glomus jugulare tumor, or paraganglioma of the middle ear.