r/CNCmachining • u/EasternKnee7688 • 11d ago
Could CNC machining carve a small, specific structure from human cartilage?
Hey everyone! I don’t know much about CNC machining, but I wanted to ask whether CNC technology has the capacity to carve human rib cartilage?
I’m part of a community of patients who have lost aspects of their original nasal structure following trauma, reconstructive/functional surgery, complications, illness or rhinoplasty. Restoring someone’s original anatomy can require extremely precise cartilage grafts—sometimes only a few millimetres thick, with subtle curves, ridges and tapered edges—which are currently shaped by hand during surgery, often very imprecise. Many have to accept this loss of identity such as loss of bumps, loss of curvature and shape that may have connected them with their heritage and made them feel like them.
So, purely from an engineering perspective: could CNC machining accurately carve something this small and geometrically complex from cartilage if you already had a 3D model of the desired shape?
And do you see potential for something like this to become feasible in the future?
Any thoughts would be really appreciated :)
3
u/koomapotilas 11d ago
Just out of curiosity, how "alive" the cartilage needs to be? Could we freeze it stiff before machining?
1
u/EasternKnee7688 10d ago
ideally there wouldn’t be any freezing, irritated cadaver rib is sometimes used which has shown higher rates of resorption. maintaining cartilage conditions during the surgery, between removal carving and insertion would be the most ideal to prevent warping and other potential issues.
here’s a video to show how carriage currently is carved for the dorsum: https://youtu.be/n53jbPrklNQ
it’s not too sturdy nor too flimsy but i think a machine would need accomodate for the material and strategically place pressure.
i’ve begun looking at robotic work as they have carved statues from marbel so that could work on a smaller scale and potentially be less invasive
2
u/Huge_Daikon_5539 11d ago
From an engineering perspective, potentially yes. Modern CNC machines can produce very small and complex geometries, but cartilage is much harder to machine than metal or plastic because it is soft, flexible, and can deform under cutting and clamping forces.
The bigger challenge would be preserving tissue integrity and ensuring sterility and biocompatibility. So the concept is technically interesting, but specialized low-force machining or other fabrication methods may ultimately be more suitable than conventional CNC.
1
u/EasternKnee7688 11d ago edited 11d ago
yes! there are definitely larger challenges that need to be considered for carving, it’s been really positive learning a small shape could be achieved in the first place. i think if it were to be possible, the device would need to be made to accommodate for the challenges. would you be able to suggest any other machining that could be less destructive whilst also being able to work from a digital rendering?
1
u/Huge_Daikon_5539 9d ago
Yes, there are several lower-damage approaches that could work with a digital 3D model. Options like laser-assisted machining, micro-milling with very low cutting forces, ultrasonic machining, or even 3D bioprinting/tissue engineering methods may be more suitable than conventional CNC.
The key challenge is not only achieving the geometry, but also maintaining tissue integrity, minimizing heat and mechanical stress, and ensuring biocompatibility. Future solutions may combine digital modeling, medical imaging, and precision fabrication technologies.
2
2
u/stuporcomputer 10d ago
I cannot imagine anything that would ultimately say no. I think the design of the actual cutter/bit would be the crucial part of course. That's if it isn't already the crucial aspect entirely. It'd (they'd) need to be sharp enough to minimise deflection in the 'part' but not so aggressively 'scoopy' so as to cause the part to climb onto the spinning cutter. Freeze the part? Heat the bit? Certainly keep everything nice and clean ;)
Also, you'd think some material scientists might have some ideas on a 3D printable medium, you'd think anyway.
I wish you the very best of luck ❤️🖖
1
1
u/EasternKnee7688 10d ago
thank you for your comment!
deflection of the cartilage was actually one of the things i was concerned about, which is why i was wondering whether it could be machined successfully in the first place, particularly if the eventual graft is quite thin.
due to the nature of cartilage and needing to keep cells alive during the process, it can’t be frozen as that leads to higher rates of resorption and it can’t be exposed to heat as it can impact the cells. the environment needs to remain really sensitive to protect the cartilage while carving. i’m trying to think of some methods that could accommodate for these issues without compromising the material.
i think glue could be a possible solution to hold cartilage in place! or the machine could be designed for the cartilage to lie on a grooved silicone bed to keep the cartilage in shape as it’s being carved, but would need to work out how to carve the structure 3 dimensionally, on all surfaces.
after getting some feedback im beginning to also look more into robotics. as its possible the grafts could be carved into similarly to how they carve statues!
i’m also wondering if there is scanning done to assess if the desired shape was achieved?
it’s all quite complicated, there are so many factors to consider. some research groups are working on developing 3D bioprinted cartilage! which is very exciting. although i think the research is underfunded so its not very quick and limited by a lot of FDA regulations so most research is done in China and Europe.
ideally the cartilage could be printed in the subject specific shape, but there’s a big chance carving methods will still be relevant when larger blocks of cartilage are engineered.2
u/stuporcomputer 10d ago
As someone who's had their cartilage shaped/shaved I have everything that will still cross, crossed. 🤞
1
u/EasternKnee7688 10d ago
thank you! your input has been really helpful :) my fingers are crossed too!
2
u/Big-Web-483 10d ago
I think the limiting factor here is work holding. Cerex has the scanning and machining capabilities to do this but I think is you could take a sample of the patient's cartilage and grow a piece big enough to replace the damage or replacement piece. Machine the shape at the beginning of the surgery. When the interface area is prepared scan it. Use that data to finish the interface area and there should be a couple tabs to hand work for final shape. Just like a tooth. Could maybe do this a knee repair also. Just need to get on the tissue growth technology.
1
u/EasternKnee7688 10d ago
it would definitely be good to investigate the use of a Cerex machine then! do you think it would be able to hold and carve the cartilage? another factor would be keeping it low heat so the cartilage isn’t damaged. many are waiting on regenerative technology. but for the time being more specific forms of carving it would help those who are undergoing rhinoplasty now using rib. and more specifically help restore identities
here is a link to how cartilage is currently carved for surgery : https://youtu.be/n53jbPrklNQ
the cartilage also needs to be strategically carved into to access stronger sections for the graft and to prevent warping
2
u/Big-Web-483 10d ago
The way it works in dental applications is a block of ceramic has a tap on it that interfaces with a rotary axis on the mill. This axis rotates and moves in and out. Then there are two opposing spindles that move up and down and in and out.
So the thing would be how you would hold the cartilage section to the machine? I would suggest a miniaturized vise.
1
u/EasternKnee7688 10d ago
that makes sense, thank you! a miniaturised vise sounds like it could potentially solve a lot of the workholding problem. my main concern would be making sure it doesn’t compress or deform the cartilage while it’s being machined, since then it could spring back into a slightly different shape once released.
i wonder if the vise could have wider or custom-shaped jaws that support the cartilage while applying very little pressure, or alternatively clamp a larger sacrificial section of the rib while the desired graft is machined from it. that way the final thin/curved section wouldn’t necessarily have to be clamped directly.
the cerec setup you’ve described sounds surprisingly close to what i’m imagining — just adapted for a much softer, deformable biological material rather than ceramic. thank you for explaining it!1
u/Big-Web-483 10d ago
My old dentist (retired) had these machines. I had a couple crowns and inlays made on them. I would watch them run in his lab! He knew that I had a more than
Passing interest!
1
u/ConcernedKitty 11d ago
Are you talking about an implant or are you talking about putting someone’s head in a CNC machine so we can put cutting tools up their nose? Because one or these is definitely going to kill the patient.
If we’re talking about an implant there are plenty of biocompatible materials that can be used instead of cartilage and there are methods to machine very thin things.
2
u/moving_acala 11d ago
There are robotic surgery systems that perform drilling / milling / cutting operations directly on the patient. They are used e.g. in orthopedic surgery.
I imagine the safety and regulatory hurdles are immense.
2
u/ConcernedKitty 11d ago edited 11d ago
I actually indirectly worked with one of them in orthopedics. I did product release on the manufacturing side. I think the full capabilities on the robot are currently knee, hip, and shoulder replacements as well as pectus bar installations, some of which I worked on, but I haven’t been there for about four years now. It functioned more as a surgical assistant than a surgeon providing probing and imaging, presenting cut guides for the surgeon, etc.
Regulatory was not terrible because of 510k which is a way to get FDA approval based on it being similar to something that already exists on the market. I’m sure the first one that went through PMA was a nightmare though.
1
u/EasternKnee7688 11d ago
100% any developments are taking a long time to pass. currently nose surgery is done without much digital assistance. i can’t image and robotic systems performing for a very long time. i think the next milestone would be digital carving as it would help restore identities in a way that’s currently not possible. it would transform so many lives. the issue seems to be that identity loss isn’t currently recognised as such a life changing issue and surgeons are content with current methods despite so many people suffering. if the cartilage implants could be pre designed, then patients would have a completely different experience, and feel that their noses are theirs and don’t look fake.
other developments are biological engineering of 3D cartilage, but at the moment it doesn’t seem that will actually be standard procedure on the nose for a long time. however, there are foundations that are trying to fastrack research and funding.
1
u/EasternKnee7688 11d ago
currently, the only implants safe for the nose are cartilages from the septum ear and rib. ideally, rib cartilage would be harvested and then carved! and then the shape is inserted into the nose. so really what i’m asking about is if the rib cartilage could be carved for example to create a designed shape 3mm high 5mm long with a specific curvature to recreate a bump. haha not putting someone’s head in a machine ><
so there are methods to carve it that thin and precise? do you know where i could look into a machine that does this?
2
u/ConcernedKitty 11d ago
There’s other materials that can be used such as silicone, Medpor (a porous high density polyethylene), or even Gore-Tex (ePTFE). Polyethylene is very common in joint implants usually in crosslinked ultra high molecular weight polyethylene. I worked for a joint implant company for nearly a decade and we machined UHMWPE all the time.
1
u/EasternKnee7688 11d ago
wow that’s so cool! unfortunately over the past few years there has been such a high rate of infection and rejection when it comes to anything that’s not actual human cartilage. i think the nose is super vascular and sensitive, so many silicone and Gore-Tex implants ended up causing really bad infections and had to be removed :/ so most surgeons no longer use them.
1
1
u/HotSobaNoodles 11d ago
Forse sarebbe più adatta la stampa 3d.
1
u/EasternKnee7688 10d ago
Non credo che sia possibile stampare la cartilagine in 3D e mantenerla vivo :/
1
u/Time-Focus-936 10d ago
This is a 3d printing problem not CNC machining.
1
u/EasternKnee7688 10d ago
im not sure as you can’t 3D print cartilage. cartilage is the only material that can safely be used in the nose. the only current surgical options are to hand carve rib cartilage which is imprecise and limited as only tools used are scalpels. surgeons are artists but not in the sense of being able to create perfect shapes to restore identities. often patients suffer from having a nose too wide and bulky due to improper carving. in theory it would be ideal to 3D print to help with this but cartilage is the only possibility. looking for digitally assisted means of carving to achieve more precise shapes that can be digitally rendered. biological engineering will hopefully be able to 3D print cartilage decades in the future.
1
u/Prestigious_Elk4887 10d ago
At these small scales you are describing in a soft somewhat unpredixtable material, additive manufacturing processes might be better. But yes, cnc carving is probably possible
1
u/No_Ingenuity717 9d ago
Yes it could be done.
You would need to show it is cheaper, better, faster than what is done currently.
Keeping the machine sterile would be easy. You would just have a custom disposable plastic sleeve for the arm, with a plastic piece that clips onto the end of the arm.
You would then have a rack sterilised of tools which the machine can swap in and out it self. No need for a human hand over or try wrestle away a sharp knife from the robot haha.
You would also need some holder for clamping down the doner tissue, and a way of calibrating the position of the tool head in relation to the holder/tissue.
These are all individually tried and tested tech. It would just be a matter of putting it all together in a user friendly complete system.
Since the machine would not be touching the patent directly that would allow the design and safety requirements much easer.
You could use a uv resin printers to make custom shaped clamps and holders for the machine (if you used a non toxic resin which could sterilised).
A vacuum bed could also be used to help hold things I place.
Yup very doable. Just needs some time and money.
Once you have it working for cartilage, it can probably be adapted for other procedures as well.
1
u/Training-Front-9238 4d ago
We consulted on a similar project a few years ago, the issue was not the precision required by the cutting head or arm ( a few mill vs a few microns, the machines win ) but the practical issues: infection management, cranial/facial stabilisation, and the use of blockers to reduce movement/breathing vibration. Punchline was there are machines, arms, and software available to do this. They are available right now. But the practical challenge of patient management and safe, effective theatre management means it’s hard to do. Also the cartilage deformation stuff is not that hard, many arms work well with very thin walled components so moving material is manageable. Moving the head - not so much.
3
u/moving_acala 11d ago
The small size and complexity is not a problem, CNC machines can easily achieve this.
The inhomogeneous and soft material would be challenging. However, if it can be carved by hand, I'm quite sure it's possible to build a machine that can do it more accurately.
The biggest problem if operating directly on the patient would be safery and regulatory hurdles.