Aurélien

The illustration below represents the nasal cavity, the anterior part in red, the middle meatus in green and finally the inferior meatus in blue.

The following illustration represents the negative of the nasal cavity, that is to say the air which is inside the nasal cavity. All illustrations that follow will be represented in this manner. The block that sticks the nostrils simply represents the air around it.

Right side: We can see that the right turbinate is almost completely cuted, just a little bit of the head remains. In red it is a cartilage implant mostly positionned in the anterior part.

Left side: On the left side we can say that around 50% of the left turbinate is missing.

We can also see that the septum is still twisted despite septoplasty. The right middle turbinate is almost absent due to the twisted nasal septum which has compressed it.

The current lines represent the air flow, the speed scale goes from 0 to 2.5 m/s. Speeds above 2.5 m/s are shown in red.

The flow of air which passes mainly through the middle meatus is apparently a characteristic of ENS. The airflow velocity is a little higher in the lower meatus in the right side compared to the left side due to the cartilage implant.

In the red zone the airflow is accelerated due to a section restriction, so no volume should be added to this zone.

The areas colored red represent areas where the WSS is greater than 0.2 Pa. That is to say, these are the areas where the air rubs the most against the mucosa and therefore creates the most air sensation.

We can see that the areas where the WSS is the highest are mainly the anterior part and to a lesser extent the middle meatus. This is not surprising given that there is almost no airflow into the inferior meatus.

49% of the airflow passes through the right side and therefore 51% on the left.

The flow ratio between the two sides is 1.03.
So the airflow is well balanced between the two sides.

The right nostril is more colored than the left, this means that the pressure loss is higher on the right than on the left. However the imbalance is quite low.
The nasal resistance, measured from the nostrils to the choana, is about 6.2 Pa. In a CFD study [1] of 35 subjects at the same flow rate (15 l/min), healthy noses fell between 7 and 17 Pa and post-surgical empty noses below 5.5 Pa.
1.Esteban-Ortega F, Rosique-López L, Ochoa-Ríos JA, Rodríguez-Romero R, Burgos-Olmos MA. Empty nose syndrome: new insights from a CFD approach. Eur Arch Otorhinolaryngol 2025;282:1319–1326. doi.org/10.1007/s00405-024-09122-w

The further away from the nostrils, the bigger the cross sectional area is. It is of course the consequence of the turbinectomy. The section is stabilised at around 350 mm² which is around 100mm² bigger than the control group.

The data of the control group are pulled from a study [2], but I have seen some non ENS case at around 300 mm². So I think that between 200 and 300 mm² the values can be considered normal.

Temperature of the air along the cavity (0 to 40 mm from the nostrils).
The simulation assumes a well-perfused mucosa at 34 °C. On an atrophic mucosa the actual warming is lower: these values compare one anatomy with another rather than predicting a measurement.

We can see that at 40 mm from the nostril, there are still zones at 29°C, which seem to be a bit low.

A lot of volume is missing on the right in the middle and posterior part. The cartilage implant only added volume in the anterior part. On the left there is also a lack of volume all along, especially between the turbinate and the floor. Most of the airflow passes through the middle meatus, the airflow imbalance is normal.