السبت، 16 أبريل 2011

Nasal polyp surgery

Background
Polyp formation in the nasal cavity is due to chronic allergic rhinitis, chronic sinusitis, and, less commonly, underlying disease such as cystic fibrosis. Patients usually present with nasal obstruction, persistent nasal discharge (rhinorrhea), sinus infection, and loss of the sense of smell (anosmia) of prolonged duration.
History of the Procedure
Knowledge of nasal polyposis extends to medical antiquity. The disease process was mentioned in Egyptian and Indian medical treatises 2500-3000 years ago.

Through the ages, several treatments have been advocated, including cautery with hot irons, application of caustic chemical substances, abrasion by drawing rags through the choanae and out the nose, and snaring.

Today, the standard surgical therapy is endoscopically guided removal of diseased tissues with preservation of maximal amount of normal nasal mucosa.

Problem
Patients usually have chronic nasal symptoms prior to detection of nasal polyps.

Epidemiology
Frequency
The frequency of nasal polyps is uncertain. Only 0.5% of individuals with atopic symptoms manifest nasal polyposis, and most patients with diffuse nasal polyposis do not demonstrate an immunoglobulin E (IgE)–mediated type 1 hypersensitivity reaction. Patients with cystic fibrosis have a higher prevalence of nasal polyposis (up to 40%).

Etiology
Polyp development within nasal and sinus regions implicates an IgE-type hypersensitivity and an immunologic or possibly inflammatory basis for such formation.

The exact etiology of polyp formation is unknown. Research is demonstrating an eosinophil-mediated mechanism with damage to the mucosa by major basic protein, but the complicated interplay of secondary messengers and chemical mediators is not clear.

Nasal polyposis in association with cystic fibrosis, sinobronchial syndrome, aspirin sensitivity, and Samter triad (asthma, aspirin allergy, nasal polyposis) indicates manifestation of nasal mucosal damage by many different possible disease processes
.

Pathophysiology
The polyp surface consists of pseudostratified respiratory epithelium and is subject to metaplasia due to local pressure and trauma. Polyps can undergo fibrosis and neovascularization.

Presentation
Patients present with nasal airway obstruction, chronic rhinosinusitis, exacerbation of asthma, and nasal and facial deformity (rarely).[1, 2] Patients may also present with bleeding and anosmia. Not insignificantly, these patients may have undergone recurrent surgery and costly medical therapy.

Indications
The patient may require surgical intervention if severe symptoms of obstruction and infection prove refractory to medical treatment.

Medical therapies include treatment for underlying chronic allergic rhinitis using antihistamines and topical nasal steroid sprays. For severe nasal polyposis causing severe nasal obstruction, treatment with short-term steroids may be beneficial. Topical use of cromolyn spray has also been found to be helpful to some patients in reducing the severity and size of the nasal polyps.

Within the nasal and sinus region, polyps originate from the middle meatus/ostiomeatal complex. With surgical removal of diseased tissues (polyps), future recurrence of polyp formation is still possible. In endoscopic sinus surgery, the goal is to remove diseased tissue and provide adequate sinus aeration in order to prevent recurrence.

Relevant Anatomy
Nasal polyps can develop in all the paranasal sinuses, but the region of middle meatus/osteomeatal complex lateral to the middle turbinate is of great importance.

Contraindications
Severe pulmonary or cardiac problems may be contraindications to surgical treatment. Relative contraindications to surgical treatment include bleeding diathesis (which can be medically treated before surgery), acute asthma exacerbation, and the patient's inability or unwillingness to obtain appropriate postoperative follow-up care and treatment.
  



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