Navigating the ventricles with a rigid instrument
With the current neuroendoscopic equipment, a surgeon can offer the patient a treatment that leaves less scars and offers a shorter recovery time than in craniotomy or microneurosurgery .
Especially patients with conditions affecting the cerebrospinal fluid flow and pressure inside the brain’s ventricles caused by cysts, tumors, stenosis or congenital defects can be diagnosed or treated minimally invasively through neuroendoscopy .
However, when using the long, rigid system that the neuroendoscope is, there is a very limited reach at the tip. It is extremely dangerous to move the endoscope, once it is placed inside the brain, as tiny movements can have disastrous consequences such as large bleeds and permanent brain damage. This movement in the sagittal plane is illustrated in Figure 1.
Maaike Weber, design engineer:
“Working on an instrument that has such specific requirements, imposed by a very specialist user and a critical working environment was as challenging as exciting. The fact that we were able to work together in such a way that in this timespan, multiple iterations and finally a functional prototype could be produced is really cool!”
A window of opportunity
For this reason, only a small portion (5%) of the potential patients is now treated endoscopically, as the rigid instruments are not sufficiently adapted to their anatomy . To illustrate this number, that is less than 1% of all neurosurgical procedures (11 million in 2019) ! Solving these problems through introducing steerability could potentially offer many more patients the advantages of neuroendoscopy.
Introducing a 2mm diameter steerable tip
The NeuroFlex aims to increase safety of neuroendoscopic procedures by increasing the reach and concurrently decreasing the movement needed in the full endoscopic system to reach the different areas inside the brain.
The NeuroFlex is equipped with biopsy forceps and has a shaft diameter of 2mm. The distal portion of the shaft is articulate, using DEAM’s familiar steering technique. The steerable tip and how it can reach around while keeping the shaft still, is visualised in Figure 2.
Close collaboration with the clinic for an efficient process
This project is founded in a partnership between DEAM and prof. dr. Eelco Hoving, the clinical director of the neuro-oncological department of the Prinses Maxima Centre. A close collaboration was needed to define the user requirements of the instrument and to develop the prototype to the level it is at now. This fully functional prototype is shown in Figure 3.
The first steps towards the solution were taken by a graduation intern, Maaike Weber. She made an effort to collect the aforementioned user requirements and incorporate them in a fully functional prototype.
A Stable instrument for multiple purposes
The first functional prototype was evaluated and tested. The set-up for this is shown in Figure 4. Promising results were found concerning the safety of steerability in neurosurgical instruments.
In the future, this instrument with its specific dimensions and other properties (2mm diameter shaft, the joystick control, the long rigid shaft with articulate tip etc.) might proof especially suitable for other applications too!
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October 29, 2020