Building An Open-source Robotic Stereotaxic Instrument

The overall goal of this procedure is to expand the accessibility and flexibility of robotic rodent neurosurgery by providing researchers with plans to build a flexible, inexpensive, and open source robotic stereotaxic instrument, as well as the software necessary to design and share surgeries. This is accomplished by first machining and assembling a computer numeric controlled stereotaxic instrument. The second step is to determine the scaling ratio of the stereo attacks.

By measuring the stereotaxic distance traveled per motor distance, a toolpath will be automatically generated from skull coordinates and will be exported to G code. The final step is to test the surgeries using skulls of the animal species. It is designed for surgery should be modified according to the results of the test.

Ultimately, the stereotaxic instrument can be used to quickly perform and share live rodent neurosurgery. Current applications include but are not limited to craniotomies, thin skull, windows, and electrode or cannula. Lowering Robotic surgical instruments can increase the accuracy and replicability of rodent neurosurgery.

However, commercial models can be prohibitively expensive. The following protocol provides plans to upgrade an existing stereo attacks to a motorized stereo attacks. G code used to control the motors is open source and may be modified to meet surgeons highly specific needs.

The included MATLAB scripts will help early adopters to automatically generate surgeries using simple point and click menus. While only a few generated surgeries are currently supported, the robot may perform the vast majority of neurosurgery techniques used in animal models. Robotic surgeries have many advantages such as eliminating variables at certain times.

In the past 30 years, my lab has suffered through periods of low survival rates in our survival surgeries. These are frustrating periods because of the number of variables that have to be eliminated one at a time. Robotic surgery would eliminate some of those variables and simplify our troubleshooting process.

In general, it promotes more consistent surgeries and faster recovery times and fewer animal deaths. Begin this procedure by wiring the bipolar stepper motors to the connectors supplied with the driver board. Connect the green wire to a plus the black wire to A minus the red wire to B plus and the blue wire to B minus.

Next slide. The couplers over the stepper motors being careful to align the mounting holes. Then secure them using the 1220 millimeter M three socket head screws and ensure that the couplers are firmly attached to the motors.

Note that the 3D models for the couplers and collar do not include threads. The holes that are labeled with a thread size must be tapped after they're manufactured. After that, remove the set screws from the thumb grips on all three axes of the stereotaxic instrument using a small hex key.

The thumb grips are threaded, so turn them counterclockwise for removal while keeping the PTFE washers in place on the arm. Then screw the threaded end of the collars onto the threaded rods of the stereotaxic instruments arms ensure that there is no gap between the colors and the P-T-F-E-O rings. This guarantees that the coordinates are maintained when the robot changes directions.

Subsequently, secure the collars onto the threads of the stereotaxic arms using three one quarter inch nf 10 32 cup point set screws. Slide each motor and coupler over the collars and stereotaxic arms. Ensure that the motors sit flush with the arms and the set screw holes on the collars line up with the flat portion of the motor shafts.

Then secure the couplers to the stereotypes using the mounting holes and six half inch NF 10 32 cut point set screws Afterward, secure the collars to the motor shafts using three quarter inch NF 10 32 set screws. Now prepare the CNC driver board by setting each of the three step controllers to half stepping, which allows for double the step resolution for each of the three step controllers. Flip pin one to the on position pin two to the off position pin three to the on position pin four to the off position, pin five to the on position and pin six to the off position.

Plug the x, y and Z motors into the stepper motor driver along with the 12 volt power supply. Then attach the stepper driver to a computer serial port using a DB 25 cable. Now open the CNC milling software to begin configuration for the stepper motors communication.

Please note that the following instructions are intended for use only with a TB 6 5 6 0 stepper motor driver. Click config, then ports and and output signals. Fill in the prompt and hit apply.

Then click config ports and pins and input signals. Fill in the prompt and hit apply. Next, click config.

Then ports and pins and motor outputs. Fill in the prompt and hit apply. After that, click config and motor tuning.

Fill in the prompt and click save axis settings and repeat these steps for all three AEs using the same values. Next, calibrate the stereotypes to the scale of the CNC software by setting the motor's velocity to one inch per minute and jog the stereotaxic instruments Z axis with page up page down to the nearest millimeter, zero the Z axis and jog the stereotaxic instrument one millimeter. The distance traveled on the Z axis in Mach three is the scaling constant.

After performing random tests of all three axes by programming them to travel some known distances to ensure the movements are accurate, attach the micro motor drill to the stereotaxic instrument using the extra large probe holder. First place all of the custom scripts from the software table into a single folder on a pc. Then open the script sharp edge craniotomy M and run the code.

Select both at the prompt. What type of surgery will you be performing? Subsequently, select custom to define the corners of the skull window, define the x and Y positions of the craniotomy corners.

Each coordinate must be entered in correct order After completing the form, hit okay. Next, enter three in the prompt to produce three skull holes. Then select define using coordinates and enter the coordinates of each hole from the template.

After that, define the drilling parameters for the first test surgery. Accept the default values. Name the G code.

It will be automatically generated and saved to the working directory. Load the G code into the CNC milling software and a test skull into the stereotaxic instruments. Ear bars manually jug the drill bit torema using the keyboard's arrow keys, use a slow jog speed to ensure accuracy.

Now start the micro motor drill and set the speed dial on the drill controller to 50, 000 RPM. Press cycle start. The stereo attacks will perform many passes of the same cut at different depths between each pass.

The stereo attacks will pause so the surgeon may continue or abort.Cutting. Press continue cycle to continue cutting passes. Here is a skull showing the end result of running the previously designed surgery, and this skull shows a skull screw inserted into a hole.

Produced the drill bits size will determine the hole's, diameter, and consequentially the screw size. This figure shows the skull containing a thin skull window indicated by the arrows. Note that in the right panel, light seems to penetrate the thin skull window.

Uniformly Robotic surgical devices can help solve some of the most common problems in neuroscience today. First, tool paths are 100%reproducible. Second, it can reduce experiment or error.

Third, motorized surgical devices can reduce the number of animals needed to perform an experiment, and finally, they're more precise and accurate than the human hand. We have included custom software that allows researchers to automatically generate simple surgeries. It's important to remember that the motorized stereo attacks is not constrained by this software.

Researchers may code complex tool paths to best suit their unique neurosurgeries. Still, the accuracy of the robot depends on quality machining, proper setup, and proper understanding of how A CNC machine operates. As long as researchers are willing to take the time to understand the functioning of this motorized stereotactic instrument, they may perform surgeries more accurately with better replicability and less training.

Overall, automated surgery provides many benefits. Motorized stereotactics exist. They're commercially available, but they're extremely expensive.

The system that Kevin and David have put together here is of the same high quality, but for a very low cost, and they're making the software and the system freely available to the whole research community.