Fluid simulation

Introduction

In this document I have grouped different cases of airflow simulations.
The original version.
The version by removing my existing implant to see what impact it had.
The version of virtual implants that I imagined was the best in my opinion.
The version of what Professor Piazza offers me.

Parameters of the study

Flow used for the fluid study 15l/min.
Inspiration phase.
Humidity and temperature are not taken into account.

CT-SCAN

Real implant and my virtual implants

Piazza virtual implants

Virtual implants mix solution

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.

Original: My existing implant is represented in red.
Virtual implants are represented in bleu, the strategy is to add volume in order to have a distance of approximately 3 mm between the walls.
Piazza virtual implants: The volume added is represented in green, so it's an increase in size of the head of the turbinates and a little in the body too.
Virtual implant mix solution: The volume added is represented in orange.
At right I increase the size of the root of the inferior turbinate and also I added volume on and behind the existing implant in order to create the shape of the missing turbinate.
At left I increased the size of the inferior turbinate mainly in the bottom part and I added volume in the septum.

Airflow velocity

Real implant deleted

Original

After virtual implants

Piazza virtual implants

Virtual implant mix solution

Real implant deleted

Original

After virtuals implants

Piazza virtual implants

Virtual implants mix solution

Real implant deleted

Original

After virtual implants

Piazza virtual implants

Virtual implants mix solution

Description and analysis

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 majority of airflow passes through the middle meatus.
The maximum air velocity is reached in the anterior part.
Turbulence is present in the inferior meatus.
After real implant deleted there is no big change in the airflow.
After the virtuals implants we can see a slight increase in velocity in the inferior meatus area especially in the right side. It is a good thing, we can expect more sensation in this zone if the WSS increases too.
After Piazza virtual implants there is no big change in the airflow. Maybe a little less velocity in the posterior part.
The airflow of the virtual implants mix solution is like the Piazza implant but better, especially in the posterior part. We can see than the red zone descends lower which indicates a better distribution of airflow between the middle and lower meatus.

Wall Sheer Stress

Real implant deleted

Original

After virtual implants

Piazza virtual implants

Virtual implants mix solution

Description and analysis

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.
Real implant deleted: The color changed from green to blue in the area where the implant was deleted.
Virtual implants: The floor is more colored than the original.
Piazza virtual implant: There is more red zone in the anterior part and the middle part of the nasal cavity, That corresponds of the area where the turbinates have been increased in size.
Virtual implants mix solution: It is like the Piazza implants but with a bit better WSS in the inferior meatus. So there is less WSS on the floor than the virtual implants due to the absence of floor implant.

Nasal resistance

Description et analyse

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 7.9 Pa on the left and 9.2 Pa on the right.
Real implant deleted 10,5 Pa
Original 10,5 Pa
After virtual implants 11 Pa
After Piazza virtual implants 11,3 Pa
After virtual implants mix solution 11 Pa

Airflow imbalance

Real implant deleted 46% at left and 54% at right.
Original 44% of the flow passes to the left and therefore 56% to the right.
Virtuals implants 53% of the flow passes at the left and 47% at right. So this has reversed and the gap has decreased.
Piazza virtual implants 55% at left and 45% at right.
Virtual implants mix solution 54% at left and 46% at right

Percentage of the airflow in the inferior meatus

Before the virtual implants 42% of the airflow passes throught the inferior meatus and afer 47%. So again the value goes in the right direction, several studies pointed out that one characteristic of ENS is the limited airflow who passes in the inferior meatus.

Cross sectiona area

Real implant deleted

Original

After virtual implants

Piazza virtual implants

Virtual implants mix solution

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.
After virtual implants the value of the cross sectionnal area is closer to the controle group and more stable throughout the nasal cavity. Which is of course a good thing.
After Piazza virtual implant the cross-sectional area increase linearly until the value of 400mm², I think it is less good than my virtual implants. A stable cross-sectionnal area all along the nasal cavity is what we see in a control group.
The mixed implants solution is better than the Piazza solution in term of stability of the cross sectional area and also in the of peak value. It peak at 350 mm² at 20 mm from nostrils. And of course a stable cross sectional area is a good thing.