Nasalisation in the Surgical Treatment of Nasal Polyposis

The definition, pathophysiology and surgical approach of nasal polyposis (NP) are still under debate. In this chapter, NP is considered as a chronic inflammatory disease of the ethmoidal mucosa characterised on nasal endoscopic examination by the presence, bilaterally, of non-infected white-oedematous polyps originating into the ethmoidal labyrinths and most of the time, arising from the middle and/or superior meatus and/or the sphenoethmoidal recess. This definition is aimed at stressing that NP is a specific disease that can easily be recognised among all other forms of rhinosinusitis and other nasal diseases. Our opinion is that sinus ventilation/drainage or obstruction in the ostio-meatal complex is a minor pathogenic factor in NP disease. Our hypothesis is that NP is a disease generated by remnants of vestigial olfactory mucosa scattered in the ethmoidal labyrinths. Only people who have remnants develop NP. This vestigial olfactory mucosa has probably lost its histological features, but has kept some biological properties, among which is the ability to attract eosinophils. Olfaction is probably one of the oldest phylogenetic senses and eosinophils are probably one of the oldest cells of the innate immune system. Our hypothesis is that NP could be regarded as an inflammatory disease resulting from a dysfunction of the innate immune system associated to the olfactory organ. In this concept, the role of surgery for NP is to remove as much as possible of the vestigial ethmoidal mucosa. The role of the paranasal sinuses has been clarified and leads to the preservation of the different ostiums each time it is possible. Our hypothesis is that, when dealing with the NP disease, complete removal of the bony lamellas partitioning the ethmoidal labyrinth is not harmful but beneficial. The combination of these hypotheses led us to propose the nasalisation procedure as a surgical approach for NP. The aim of the nasalisation procedure is to remove the ethmoidal mucosa as completely as possible without hazards and to transform the ethmoidal labyrinth into a unique cavity opening into the nose (nasalisation). To achieve the nasalisation procedure, it is more important to know the anatomy of the ethmoidal walls than the compartmentalisation inside the ethmoidal labyrinth. The technical key point to safely perform a nasalisation procedure is to gently strip the mucosa to follow the bony structure of the medial orbital wall, ethmoidal roof and conchal lamina. Our results show that NP is a chronic disease which cannot be cured, but that the underlying chronic eosinophilic ethmoiditis disease seems to be better controlled after nasalisation than after ethmoidectomy. When the medical treatment with corticosteroids fails to stop the eosinophil attraction, the aim of surgery should be to remove as completely as possible the ethmoidal mucosa, which seems to be the main attractant for eosinophils.