olfactory cleft stenosis and obstruction on paranasal sinus ct scan in pre septo rhinoplasty patients without respiratory mucosa pathology : normal variants or pathologic findings ?

Conditions: Olfactory Impairment

Summary: this retrospective studed included patients referred to our institution between december 2013 and december 2021 for septoplasty or septorhinoplasty. all patients underwent pre operatory paranasal sinus ct scan and olfactory test. olfacory cleft stenosis will be quoted as none (less than 1/3 contact between nasal septum and ethmoïd turbinates), partial (1/3-2/3 contact between nasal septum and turbinates) or total (more than 2/3 contact between nasal septum and turbinates), as well as olfactory cleft obstruction as none (opacification less than 1/3 of olfactory cleft), partial (1/3-2/3 opacification) or complete (more than 2/3 opacification).

in this retrospective study, we will include every patients over 18 years old who had a septoplasty or septorhinoplasty between december 2013 and december 2021 and who underwent paranasal ct scan and olfactory test (sniffin stick test). the patients will be find thanks to social security code gama007 for septoplastie, gama 004, 010 for septorhinoplasty and olfactometry gjqp001. the patients with mucosa pathology on ct scan or with record of chronic respiratory rhinitis, septum perforation or a pathology that can alter the olfaction on the consultation report will be excluded. olfactory measurements were performed before surgery using the threshold and identification subtests of sniffin stick test. olfactory status will be classified by taking into account the normative data provided by hummel et al and the real identification score. the patients will be classified as normosmic if the threshold and the identification score is superior the tenth percentile. if not, they will be classified as anosmic if both score are 0 and hyposmic otherwise. 2 experienced radiologists will perform the measures on paranasal sinus ct. they will be blinded to olfactory results. the olfactory cleft boundaries were determined in the coronal plane : anterior boundary was defined by the anterior attachment of the middle turbinate; the posterior boundary corresponding to the anterior face of the sphenoid sinus; the lateral boundaries were defined as the attachment of the middle and/or superior turbinate laterally and the nasal septum medially. olfactory clefts were divided into an anterior and a posterior compartment, defined as "middle olfactory recess" and "superior olfactory recess", laterally bounded by the middle and the superior turbinate lamella, respectively. each olfactory recess width, global olfactory cleft width and cribriform plate width will be measured in the coronal plane, at the level of the cribriform plate and 5mm underneath at 5 different sites : 1. - first slice depicting the cribriform plate (entry of the middle olfactory recess) 2. - middle of the middle olfactory recess (halfway throuh 1 and 3) 3. - first slice depicting the head of the superior turbinate (entry of the superior olfactory recess) 4. - middle of the superior olfactory recess (halfway through 3 and 5) 5. - anterior face of sphenoid sinus olfactory cleft length will be determined in the sagittal plane as length of the cribriform plate. olfacory cleft stenosis will be quoted as none (less than 1/3 contact between nasal septum and ethmoïd turbinates), partial (1/3-2/3 contact between nasal septum and turbinates) or total (more than 2/3 contact between nasal septum and turbinates), a global olfactory cleft status will be obtained : no significant or partial stenosis in any compartment, total stenosis in case of complete stenosis in every compartment and intermediate stenosis in any other situation. olfactory cleft obstruction will be classified as none (opacification less than 1/3 of olfactory cleft), partial (1/3-2/3 opacification) or complete (more than 2/3 opacification). olfactory cleft lateral boundaries will be evaluated for the presence of a lamellar pneumatization (superior, middle or lamellar concha bullosa). olfactory groove depth was classified according to the keros classification in regard of the middle and superior olfactory recess. as well as olfactory cleft obstruction as none (opacification less than 1/3 of olfactory cleft), partial (1/3-2/3 opacification) or complete (more than 2/3 opacification).

Eligibility criteria:
inclusion criteria: * patients over 18 years old who underwent paranasal sinus ct and olfactory test before septoplasty or septorhinoplasty exclusion criteria: * respiratory mucosa pathology on ct (polyposis, opacification of the maxillary sinuses, ethmoid cells, frontal sinus, sphenoidal sinus, sinonasal tumor) * septal perforation * chronic respiratory rhinitis (allergic, vasomotor, mucoviscidosis) * pathologie that can alter olfaction (multiple sclerosis, meningioma, post infection such as covid)

Keywords: olfactory cleft stenosis sniffin stick test non mucosa pathology olfactory recess olfactory cleft obstruction olfactory normal variant