document: modern nasal surgery takes into account the cosmetic appearance of the nose but also seeks to improve the natural functions of the nose . 
   furthermore , in modern respiratory medicine , objective measurement of airway patency is a must . 
   measurement of nasal cavity geometry has proven to be a great challenge for researchers in modern rhinology . 
   the most common method used in these measurements is acoustic rhinometry ( ar ) , which is based on analysis of reflected acoustic impulses [ 3 , 4 ] . 
   it has demonstrated that the cross - sectional area of the nasal airway measured by acoustic rhinometry and the area found by calculations using data from rhinomanometry has close correlation [ 3 , 5 ] . 
   furthermore , several significant associations between nasal cavity dimensions and nasal airflow have been reported . 
   and the most important benefit of acoustic rhinomanometry is that is easy to perform and requires less cooperation from subject . 
   however , nose geometry may be influenced by various factors including race , age , sex , height , weight , and smoking habit . 
   we evaluate the changes in nasal dimensions of healthy iranian volunteered for cosmetic rhinoplasty after surgery using acoustic rhinometry and comparing differences in length , minimal cross sectional area ( mca ) , and volume of each nasal cavity before and after surgery . 
   the cases were all healthy , without any prior history of nose surgery , fracture , allergy or asthma , and sinus disorders , and they had no complaint about nasal obstruction . 
   all cases were iranian aged at least 18 who were visited in ent clinic of rassul - e - akram teaching hospital between 2006 and 2008 . 
   the surgeries according to the structure of the nose were open rhinoplasty with or without septoplasty . 
   t - type of osteotomy ( single versus double ) , placement of columellar strut , or other variations of surgery were dependent on the surgeons preference . 
   all operations were performed by a single experienced surgeon , and septoplasty was performed in the case of moderate - to - severe septal deviation . 
   the device was consists of a sound source ( loudspeaker ) distally positioned in relation to a 24  cm tube equipped with a microphone for acquisition in its proximal portion . 
   a sound pulse was generated with a peak power of 146  db sound pressure level and a 50-ms duration . 
   all measurements were performed after a short period of acclimatization and in a relatively quiet room at normal temperature ( mean = 21.4c ) to minimize artifacts from physical stress , environmental noise , and temperature changes . 
   the measurements were performed during a breathing pause while patients were in a sitting position . 
   the nosepiece used in the measurements was 5  cm in length and was anatomically sculptured . to ensure a tight connection between the nosepiece and tip of the nose , 
   a small amount of ultrasound transmission gel was applied to the edge of the nosepiece . 
   care was taken not to obstruct the nasal vestibule with gel or deform the nose during testing . 
   the angle of the incident acoustic impulse was about 45 with respect to a line joining the base of the piriform aperture of the nose to the tragus . 
   measurement performed in either of two conditions of without a decongestant and with a decongestant , respectively . 
   the first measurement performed before surgery and the second measurement performed 3 months after surgery . 
   the technique we used allowed us to analyze two local minimum points giving us minimum cross - sectional areas ( mca1 and mca2 ) and distance ( d1 and d2 ) to the points from the nostril and volumes of nostrils . to examine the geometrically difference in pre - and postoperative nasal cavities , paired t test used for repeated measurements . 
   mean age ( sd ) of cases were 24.63 ( 4.4 ) years , minimum age was 18 , and maximum age was 40 . 
   none cases had complaints of breathing problems before and after the surgery , and all of our cases were satisfied with their surgery result . 
   mean ( sd ) geometric values of cases preoperatively with and without decongestant are demonstrated in table 1 . by the pair wise comparison of cases without decongestant before and after surgery , 
   right ( r ) d1 , bilateral d2 , and left ( l ) mca2 did not change significantly after surgery . 
   however , pairwise comparison of nasal dimensions with decongestant revealed that bilateral d2 and v did not changed significantly postoperatively . 
   bilateral d1 and both mca2 decreased significantly , while significant increase was observed in mca1 postoperatively ( table 2 ) . in order to assess the result of septoplasty , patients divided into 2 groups of rhinoplasty plus septoplasty and rhinoplasty alone . 
   comparison of the finding showed that cases with septoplasty would experience more increase in mca1 ( increase in mca1 was significant and much more in decongested state of group with septoplasty ) and less constriction in mca2 postoperatively ( significant constriction were observed in both groups . however , amount of this constriction was more in group without septoplasty ) ( table 3 ) 
   . in cases of rhinoplasty without septoplasty , increase in mca1 was significant only in group of single osteotomy without decongestant . 
   although changes in mcv2 were significant in both with and without decongestion groups of double osteotomy , but the net effects were not clinically significant comparing single osteotomies . 
   table 4 demonstrates that cases with rhinoplasty alone would benefit from double osteotomy in mca1 . 
   effect of osteotomy on patency of nose in cases with septoplasty is shown in table 5 ; it is more prominent at the level of mca1 . 
   placing a columellar strut in group of cases of rhinoplasty plus septoplasty has significant effect both at mca1 and mca2 levels ( table 6 ) . in cases of rhinoplasty alone , placing a columellar strut caused greater amount of increase in mca1 . 
   mca2 after decongestion significantly increased in group without columellar strut , but it did not changed in group with replacing a columellar strut . 
   regression analysis of difference after surgery in mca1 , mca2 , and v revealed no fix significant effect for septoplasty , osteotomy , and placing a columellar strut . 
   advanced equipment for these methods is now available , and most devices are reliable provided that care is taken to calibrate the device properly . in the current study , we used an ar to measure the dimensions of the nose . 
   ar evaluation of the nasal airway has been reported to be accurate when compared with mri2 and ct [ 15 , 16 ] . 
   the closest correlations have been noted after decongestant use and in the most anterior 5  cm of the nasal cavity . 
   it is believed that acoustic rhinometry provided less variability of results than those obtained with rhinomanometry . in the study of corey 
   he concludes that the anatomic correlate of csa1 ( cross - sectional area ) is not as clearly delineated ; however , it likely corresponds to an area at or near the nasal valve . 
   furthermore , csa2 correspond to the general areas of the anterior portions of the inferior turbinate . 
   he claimed that in conjunction with a careful clinical exam , ar can provide objective documentation and diagnosis for better treatment of nasal airway blockage . 
   acoustic rhinometry also seems very suitable for evaluation of the nasal cavity in cases where septoplasty and turbinoplasty is considered as well as for the postoperative objective evaluation . 
   studied the changes in nasal airways after le fort i osteotomy and functional rhinosurgery with both ar and rhinomanometry techniques . 
   he declare that rhinomanometry and acoustic rhinometry are reliable and objective methods of determining functional and geometric changes in the nasal cavity after le fort i osteotomy . in this paper 
   we described reference values in normal and decongested noses of normal iranian population with acoustic rhinometry . 
   all of our cases were normal people without significant symptoms of nasal dysfunction in their nose , and surgery was performed just because of aesthetic reasons . comparing our finding with mohebbi et al . 
   , in iranian population , no significant difference was observed in mcas and v. this finding supports the original idea of study to enroll cases with normal nose geometry .   by comparing nose geometry before and 
   after surgery in both normal state and decongested state , considering presence of inflammation after surgery and more precise estimation in decongested estate , the main findings were a reduction in d1 , an increase in mca1 , a decrease in mca2 and no change in v and d2 . 
   these findings are consistent with findings of greymer that reported reduction in internal dimensions of the nasal cavity especially the anterior dimensions . 
   this finding highlight the fact that second constriction is a critical place during the surgery and adequate attention should be paid to this point . 
   the anatomic correlate of this point is anterior portion of the inferior turbinate , hence decreasing the resistance in this region could be beneficial for patients . 
   operations on the nasal septum are frequently performed with the intention of improving the nasal airway . 
   for this reason , they form much of the routine workload in most otolaryngology departments . a meta - analysis performed by singh et al . demonstrated that an overall significant improvement following surgery is present in patient undergoing septal surgery .   in our study , 
   comparison of cases of rhinoplasty with and without septoplasty revealed that the cases with septoplasty would experience more increase in mca1 and less constriction in mca2 . 
   as a conclusion , even in the cases which mild septal deviation is present , performing the septoplasty may increase patient nose patency . 
   more increase in mca1 and no significant effect on mca2 were observed in patients in double osteotomy group comparing group of single osteotomy . 
   it seems as if double osteotomy positively affects nose function by more increase in mca1 . 
   double osteotomy is positively affecting mca1 considering the cases without septoplasty or cases with septoplasty . in either group of rhinoplasty with and without septoplasty , placing a strut was beneficial for patients . in the study of oeken and kiefer on 52 cases of septorhinoplasty total nasal airflow 
   it should be mentioned that in the above study , all cases suffered from a deviated septum and some degree of obstruction . 
   anselmo - lima et al . in a study of 30 cases of rhinoplasty with lateral 
   osteotomy observed that there is a reduction in nasal valve area ( significant reduction in mca1 ) as well as in anterior volume of the nose . 
   they propose more criteria to indicate rhinoplasty , because the procedure might lead to nasal obstruction . in the study of kemker 
   patients in the septoplasty - only group showed a statistically significant increase in volume as measured by ar . 
   patients who had septoplasty plus other sinonasal procedures showed significant increases in volume and cross - sectional area ( csa ) 3 , whereas csas 1 and 2 increased also , but not significantly . shemen and hamburg studied 24 patients undergone septal surgery , and skouras et al . studied 16 patients , the improvement in nasal patency was seen in both studies . 
   however , cases in both studies have complained of nasal obstruction before surgery [ 25 , 26 ] . in a study by can et al . on 26 children with septal deviation 
   the results showed that the surgery was successful ; however , they claim that surgery should be restricted to only the pathologic area and should be conservative . 
   as we know , ar has some limitations , as it can not measure the columella width in nasal geometry and also differentiate the nostrils shape that has effect on the turbulence of air delivered to nasal cavity . 
   as we know , the cross - sectional area of the nose is a major factor in the determination of airflow , with airflow increasing as the cross - sectional area increases . 
   hence , according to the above findings , cosmetic rhinoplasty may generate a mix effect on nose function . 
   comparison of our finding to other studies shows that condition of the patient before surgery is the principal factor for the prediction of surgery results . 
   putting all together , surgeons should be aware of common pattern of change in nose geometry ; care must be taken in intervention in the region of second constriction . 
   performing osteotomy may better help patients to save nasal patency , septoplasty is beneficial even in mildly deviated septum , and placing a strut may be beneficial in most of the cases .
summary: objective . to evaluate the changes in nasal dimensions of healthy iranian volunteered for cosmetic rhinoplasty after surgery using acoustic rhinometry 
   . methods . pre- and postoperative nasal dimension of 36 cases undergoing cosmetic rhinoplasty 
   were compared using acoustic rhinometry ( ar ) , and the measured variables were distance to first and second constriction ( d1 , d2 ) , first and second minimal cross - sectional area ( mca1 , 2 ) , and volume . 
   results . 
   mean age ( sd ) of cases were 24.63 ( 4.4 ) years . 
   septoplasty was performed in 12 cases ( 33.3% ) . 
   after surgery , bilateral d1 and both mca2 decreased significantly , while significant increase was observed in mca1 postoperatively using decongestant . 
   cases with septoplasty experienced more increase in mca1 and less constriction in mca2 postoperatively . in cases with rhinoplasty alone , they received benefit from double osteotomy in mca1 . in either group of rhinoplasty with and without septoplasty , placing a strut was beneficial for patients . 
   discussion . 
   the cross - sectional area of the nose is a major factor in the determination of airflow . 
   cosmetic rhinoplasty may generate a mix effect on nose function . performing osteotomy may better help patients to save nasal patency , septoplasty is beneficial even in mildly deviated septums , and placing a strut may be beneficial in most of the cases .