Fabrication of Narrow Channel Medical Catheter Capable of Exhibiting Snake Like Motion for the Purpose of Ventriculostomy Procedure

Ventriculostomy is a neurologic procedure involving external ventricular drain placement to evacuate excess fluid from the brain. Current ventriculostomy technique includes inserting a rigid endoscope in a direct linear path through the brain tissue to reach the target manipulation site. The

Project Title

Fabrication of Narrow Channel Medical Catheter Capable of Exhibiting Snake Like Motion for the Purpose of Ventriculostomy Procedure

Project Area of Specialization

Mechanical Engineering

Project Summary

Ventriculostomy is a neurologic procedure involving external ventricular drain placement to evacuate excess
fluid from the brain. Current ventriculostomy technique includes inserting a rigid endoscope in a direct linear
path through the brain tissue to reach the target manipulation site. The procedure has adverse effects including
damage to brain tissue and infection as cellular flora or other pathogenic agents may be introduced during
surgery. Our group has been interested in creating a soft robotic catheter that is more dexterous and
controllable than traditional rigid catheters. The pliable nature of soft robot catheters allow for controlled
bending and inherently less destructive navigation through the brain tissue when compared to a rigid
endoscope. Decreasing operative destruction would reduce the rate of brain tissue damage providing fewer
incidences of unsuccessful operations. With respect to the infection risk associated with ventriculostomy, our
group aims to eliminate the need for catheter removal due to obstruction within the drainage channel or to alter
the path to reach the ventricles as may be required with a rigid endoscope.

Project Objectives

The main objective of our project is to fabricate soft catheter which provide local bending and overcome the ballooning effect during inflation so that catheter easily reach to the cerebral ventricles in the brain and the excess fluid can be drained out. Project objective is to limits the number of entries, and reduces manipulation of the catheter once within the cranium. 
Our design catheter, which would be capable of doing a medical procedure with control and safely manners. Soft catheter is to overcome the introducing infectious bacteria into the cerebral flora. Our design catheter will attempt to mitigate blockages in the working channel of the catheter from environmental debris. Automatic blockage removal will reduce the operating time as well as reducing the need for surgeons to irrigate the surgical site.
Doctors faced great difficulty during External Ventricular Drainage (EVD) operation doctors used rigid catheters during operations and it is not easy to reach the ventricular part of brain of patients doctors have to navigate to the ventricular part manually and identify the path by themselves which can sometimes cause problem to patient that can leads to death. Our project objective is to provide ease to the patients and doctors during operation also reducing the risk of death. 
Soft neurological external ventricular Drainage (EVD) catheter can assist the doctors to take out the excess fluid present at the cerebral ventricles by a snake like motion through local bending of air channels pneumatically and the fluid can be taken out from the working channels present at the ends of catheter.

Project Implementation Method

In the execution phase the catheter is molded with a Dragon skin 20 (Silicone based material) The molding process consists of following steps. Firstly, the mold is machined for our catheter the precision for the mold is set to 10th order of the required dimension as our catheter is very small in size and have hollow channels inside the catheter, so for the accurate results as in the analysis done the accuracy should be high for that we used CNC machining and taking care of using a right tool for the right operation. Secondly the molding of silicone based materials like Dragon Skin is not easy to handle as working with the materials in an open environment can introduce the air bubbles in the material to overcome that we used a Vacuum Degasser which creates the vacuum in a chamber and takes out the bubbles from the material to be on the safe side we performed the molding process inside the vacuum chamber so that no bubbles can be enter from the environment the mold is sprayed with the Ease releaser 200 so that it’s easy to take out the finish product from the mold. Lastly, the molding is performed and the material is poured inside the mold the curing time for the Dragon Skin 20 is 16 hours, for that the mold is clamped from both ends tightly so the catheter should acquire the required dimensions after that it’s leave it for 16 hours so that material complete its curing time. After Molding the catheter, second phase is to control the catheter pneumatically for that a pneumatic system control board is prepared using raspberry pi as a microcontroller and a solenoid valve which will be control by the raspberry pi and a motor which can create air pressure. A proper piping system is arranged for catheter with the pneumatics board and the bending of catheter is control with GUI on screen which doctors can easily interact and perform the ventriculostomy operation without any hassle to remove the catheter repeatedly to reach to the target area. The bending of the catheter is done carefully with slightly bending the catheter making sure not to damage the tissues of the brain by localize bending of the catheter

Benefits of the Project

As our catheter based on soft robotic, so it will provide flexible motion which is also useful for internal body operation because as we inserted it inside the brain at any position then it is possible that the catheter may not reached to the exact position, as mentioned above the catheter is flexible, so we can rotates the distal pointed tip at two location right and left and our catheter body also contain position for pneumatic mechanism which allow it to move the catheter body it two direction which is right and left that provide higher approaches toward different positions.
Due to traditional catheter we cannot operate the operation in a safe zone like there is an obstructions that occur due to the introduction of cellular debris in the working channel that will creates pathogen due to repeated entry and exit of catheter, so our catheter has provided feasibility during operation like, it will remove the obstructions that occur due to the introduction of cellular debris in the working channel that directly reduced the repeated entry and exit of catheter because it increases the likelihood of contamination and causes trauma to the brain tissue.
Old rigid catheter based on hard material and the accuracy of operation were very low that was decrease the chance of successful operation and their controlling mechanism were also very tedious like if any problem occurs during insertion, it will need to exit and then entered again that’s become a time taking process, so this soft pneumatic based catheter operated through air that provide benefit as compared to other actuation principles like with hydraulic we cannot operated neurological operations just because of the limitation which is that it contain bellows and fluid, so due to uncertainty the bellows could be burst and the operating fluid spread inside the brain that will creates damage to the tissues of the brain.

Technical Details of Final Deliverable

Material selection is crucial to a successful engineering design process.Since brain is the most critical and sensitive part of our brain whether talking about medulla or cerebellum. The selection of the material must be in a way that they do not adversely affect any part of the brain or be harmful to the living tissue.
Dragon Skin™ silicones are high performance platinum cure liquid silicone compounds that are used for a variety of applications, because of the superior physical properties and flexibility of Dragon Skin™ rubbers, they are also used for medical prosthetics and cushioning applications according to Smooth-on.
Reduced N-order polynomial Hyperelastic material models  were investigated in the fitting of the tensile test data for the silicone materials, where the material was considered incompressible, and the strain energy potential U is independent from the second invariant.

These models were tried in fitting the experimental data of the mechanical tests for the tested grades of silicone in the strain range of 0–300% (or maximum strain for Dragon Skin 30), where the least square curve fit was used to determine the coefficients for the strain energy equationThe second order reduced polynomial model proved to be the best constitutive model for Dragon Skin 30

The local bending model distinct feature is being able to bend from different portion depending upon the requirements. The molding and fabrication are also simple for the model. Since the catheter must be fabricated at small dimensions, complicated model would be extremely difficult to fabricate with resources available at the time of fabrication. This model is the simple and can be easily fabricated in one mold even though the catheter is made of two modules.The semi-circular air channels area analogous to the joints in the finger. The flat portion or the diameter of the semicircular air channel would generate pressure concentration at the side towards the bending of the catheter. Moreover, stiffer material being perpendicular to the direction of the bending will escalate the bending.
Tip bending is carried out in the upper semicircular portion of the catheter. The air is supplied through 1 mm pipes/tubes. The semicircular diameter is 2mm. “As this distance decreases, the pressure required to bend the module to 90o also decreases in a linear manner while the radial expansion and associated balloon area are almost constant. Consequently, a ratio of channel wall– module wall distance/module diameter of 0.04 seems to be the optimum”

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Health

Other Industries

Core Technology

Internet of Things (IoT)

Other Technologies

Sustainable Development Goals

Good Health and Well-Being for People, Industry, Innovation and Infrastructure

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com