The Impact of Adhesions on Nasal Airflow: A Quantitative Analysis Using Computational Fluid Dynamics

Background

Nasal adhesions (NAs) are a known complication of nasal airway surgery. Even minor NAs can lead to significant postoperative nasal airway obstruction (NAO). Division of such NAs often provides much greater relief than anticipated.

Objective

We examine the impact of NAs at various anatomical sites on nasal airflow and mucosal cooling using computational fluid dynamics (CFD) and multiple test subjects.

Methods

CT scans of healthy adult subjects were used to construct three-dimensional nasal airway computational models. A single virtual 2.5 mm diameter NA was placed at one of five sites commonly seen following NAO surgery within each nasal cavity bilaterally, resulting in 10 NA models and 1 NA-free control for each subject. CFD analysis was performed on each NA model and compared with the subject's NA-free control model.

Results

4 subjects were recruited to create 44 computational models. The NAs caused the airflow streamlines to separate, leading to a statistically significant increase in mucosal temperature immediately downstream to the NAs (wake region). Changes in the mucosal temperature in the wake region of the NAs were most prominent in anteriorly located NAs with a mean increase of 1.62 °C for the anterior inferior turbinate NAs ( P < .001) and 0.63 °C for the internal valve NAs ( P < .001).

Conclusion

NAs result in marked disruption to airflow patterns and reduced mucosal cooling on critical surfaces, particularly in the wake region. Reduced wake region mucosal cooling may be a contributing factor to the exaggerated perception of nasal obstruction experienced by patients with NAs.

The impact of nasal adhesions on airflow and mucosal cooling - A computational fluid dynamics analysis

Nasal adhesions are a known postoperative complication following surgical procedures for nasal airway obstruction (NAO); and are a common cause of surgical failure, with patients often reporting significant NAO, despite relatively minor adhesion size. Division of such nasal adhesions often provides much greater relief than anticipated, based on the minimal reduction in cross-sectional area associated with the adhesion. The available literature regarding nasal adhesions provides little evidence examining their quantitative and qualitative effects on nasal airflow using objective measures. This study examined the impact of nasal adhesions at various anatomical sites on nasal airflow and mucosal cooling using computational fluid dynamics (CFD). A high-resolution CT scan of the paranasal sinuses of a 25-year-old, healthy female patient was segmented to create a three-dimensional nasal airway model. Virtual nasal adhesions of 2.5 mm diameter were added to various locations within the nasal cavity, representing common sites seen following NAO surgery. A series of models with single adhesions were created. CFD analysis was performed on each model and compared with a baseline no-adhesion model, comparing airflow and heat and mass transfer. The nasal adhesions resulted in no significant change in bulk airflow patterns through the nasal cavity. However, significant changes were observed in local airflow and mucosal cooling around and immediately downstream to the nasal adhesions. These were most evident with anterior nasal adhesions at the internal valve and anterior inferior turbinate. Postoperative nasal adhesions create local airflow disruption, resulting in reduced local mucosal cooling on critical surfaces, explaining the exaggerated perception of nasal obstruction. In particular, anteriorly located adhesions created greater disruption to local airflow and mucosal cooling, explaining their associated greater subjective sensation of obstruction.

Subglottic Stenosis in Wegener's Granulomatosis Limited to the Head and Neck Region

Subglottic stenosis as a complication of Wegener's granulomatosis (WG) is a relatively rare lesion and is difficult to treat surgically once stenosis becomes sufficiently severe to cause inspiratory dyspnea. Thus, it is important to diagnose WG in its early stages to prevent troublesome subglottic stenosis from developing by initiating immunosuppressive therapy. The authors report on a 30-year-old woman suffering from subglottic stenosis of sudden onset due to protracted WG limited to the head and neck region. She had had exudative otitis media for 13 years and saddle nose and nasal crusting for five years. Repeated biopsies of the nasal mucosa and enzyme-linked immunosorbent assays for cytoplasmic patterns of antineutrophil cytoplasmic autoantibody (cANCA) had failed to establish the diagnosis. However, further histologic examination of the nasal mucosa showed vasculitis, and indirect immunofluorescence delected the presence of cANCA. Thus, the diagnosis of WG was confirmed 13 years after the appearance of the initial symptoms in the ear. The patient was given prednisolone (60 mg/day for five days), which greatly relieved the subglottic stenosis. The prednisolone dosage was then tapered to 5 mg/day.

[Otolaryngological manifestations of Wegener's disease]

INTRODUCTION

Wegener's granulomatosis (WG) is characterised by granulomatous vasculitis of the airway and glomerulonephritis. Since its first description, important advances have occurred in diagnosis and treatment; however, the aetiology remains unknown. Involvement of the head and neck region can often occur as the first and only manifestation. The aim of this study was to determine the frequency of symptoms and signs in the region of the nose, ears and pharynx-larynx in a group of patients with WG.

MATERIALS AND METHODS

We evaluated 17 patients with WG defined by clinical, laboratory and pathology criteria. Detailed histories were taken and an ENT physical examination, audiometry, tympanometry and nasofibrolaryngoscopy were performed in all patients.

RESULTS

The average age was 41.7 years and the average disease time was 9.12 years, ranging between 1 and 40. In these patients, 9 (53.1%) reported hearing loss and had altered audiometry, and 5 (55.6%) had bilateral sensorineural hearing loss. In the nose, nasal obstruction in 11 (64.8%) and rhinorrhoea in 10 (58.8%) were the most prevalent; there was altered endoscopy in 12 (70.2%). In the pharynx-larynx, dyspnoea in 6 (35%) and hoarseness in 7 (41.2%) were the most prevalent and 7 (41%) had an altered laryngoscopy.

CONCLUSION

The otolaryngologist plays an essential role in diagnosis, treatment and follow-up of these patients. Knowing common symptoms makes diagnosis and treatment easier and earlier.

Management and follow-up of localized Wegener's granulomatosis: a review of five cases

OBJECTIVE

To evaluate the complications, efficacy of surgical treatment and outcome in patients with the localized form of Wegener's granulomatosis (WG).

MATERIALS AND METHODS

We reviewed a series of 5 patients (3 males, 2 females; age range 22-67 years; mean age 44.6 years) with WG in the upper and lower respiratory tracts.

RESULTS

Aural, nasal and ocular complications were common in our patients. All patients responded to standard immunosuppressive treatment, and all surgical treatments had a favorable outcome in the remission stage. Although there was no life-threatening disease activity during the course of treatment, minor relapses occurred in three patients.

CONCLUSIONS

Patients with localized WG may have a better outcome than those with systemic WG, but complications due to the disease or medication must be actively managed. Reconstructive surgery for patients with WG is safe and effective during the remission stage.

Foreign body granuloma of the external auditory canal

External auditory canal polyps are most commonly inflammatory in nature but may also manifest more severe disease. Prolonged conservative therapy may delay the correct diagnosis and appropriate intervention. A case is presented of a child with chronic otorrhea treated for 4 months with topical drops and antibiotics. On referral, a large external auditory canal polyp was confirmed to represent a foreign body granuloma covering a large electrical cap, with erosion approaching the facial nerve. External auditory canal polyps that fail to respond promptly to conservative medical therapy warrant a computed tomography scan and surgical exploration with biopsy.

Head and neck manifestations of Wegener's granulomatosis

Wegener's granulomatosis is an idiopathic, granulomatous disease with the potential for multiple head and neck manifestations. The otolarygologist is an essential part of the multidisciplinary team involved in establishing the diagnosis and providing ongoing care for patients with Wegener's granulomatosis. Diagnostic difficulties abound in Wegener's granulomatosis, making repeat biopsies and the use of ANCA imperative. Medical therapy consisting of corticosteroids and immunosuppressive agents is the mainstay of treatment in Wegener's granulomatosis, whereas surgery is reserved for selected head and neck manifestations. With appropriate medical and surgical treatment, many patients living with Wegener's granulomatosis can enjoy a good quality of life.

[Unusual presentation forms of Wegener's disease]

Wegener's granulomatosis may appear with the classic granulomatous necrotizing vasculitis affecting both high and low airway and renal glomerule, and rarely small vessels in any other location. In this way we may find generalized and localized forms of the disease. Three atypical cases of the disease are reported. The first one as a limited form with only airway affection. The second one as an unusual case of otitis with progressive affection of I, II, V, VI, VII and VIII cranial nerves. The third one was a generalized case with sinusitis and orbital pseudotumor. Both first and second cases have been controlled for a very long period of time of 22 and 14 years respectively, and none of them has presented any other location of the disease.

Wegener's granulomatosis of the head and neck

Among the more puzzling non-neoplastic necrotizing lesions of the head and neck area is Wegener's granulomatosis. This is a condition of unknown cause that may present (in the head and neck area) with ulceration of the nasal septum, sinus mucosa, oral mucosa, or external ear canal, or even destruction of the vocal cord. Diagnosis depends on the pathologic finding of a characteristic inflammatory reaction pattern (which, in its best-developed form, includes necrosis, granulomatous inflammation, and vasculitis) and the serum finding of an elevated antinuclear cytoplasmic antigen. Treatment is principally medical, with the use of powerful immunosuppressive agents. Distinction from other conditions that may mimic Wegener's granulomatosis (such as malignant lymphoma and infections) is of critical importance in constructing an appropriate treatment strategy.