Stopping grinding my gears


#1

So tonight had to work on 2 prototypes for a set of “what really grinds my gears” problems in the OR (crap falls on the floor, and somehow in the last 2500 years of surgery we haven’t figured out a good way to have crap not fall on the floor - especially if it is hooked to a tube/wire)

So first problem was with the device called the “Bovie” named after Dr. William Bovie (it’s also known as the Electrocautery) which is a RF arc knife/cautery that can either cut/cauterize or just cauterize. They are used in every type of invasive procedure, and are ubiquitous.

Well they come with the absolutely cheapest piece of crap (sorry if the guy who designed it is on the forum) holster made of injection molded nylon. It is utterly useless.

It’s a nice little shipping box, but it is so easy to knock it out, but hard to hit it when you aren’t looking to put the bovie in. And if you are using the extended tip (thoracic surgery) then it sticks more than 50% out of the box, and simply falls out (causing stoppage of the operation)…

So decided to try a quick design to see if a funnel shape with a long tail would work better. The real one needs to be a little fancier with a few extra features, but 3D printing the final shape would take hours for an injection molding prototype for testing, so this took a few minutes to design.

Ran it through the Kiri:Moto output, into DXF and then into AI. Moved the parts around to fit in the piece of scrap birch ply, and printed.

FAIL

Haha. Yeah, design for 1/8" proof grade and print on 1/4" scrap ply… Really, the tabs don’t fit? Sigh, well only 5 minutes wasted. So at least I could check that everything aligned (just not at once) and that the cuts were sane.

Yay

Recut it on proof grade 1/8" maple (and oops forgot to use the manual cut settings) but the automagic settings actually did just fine (if a bit smokier). A little scotch tape and testing in my kitchen, and it really works.

Easy to insert blind:

And doesn’t fall out when tipped (but removes easily)


Patterns for Laser cutting
Weekly Highlights for the Week Ending April 29th, 2017
#2

I love to see the GF used for prototyping! Especially devices can help out in hospitals :slight_smile:


#3

Wow. Pretty amazing! Say, can I have your autograph now, before you get the Nobel prize? I want to be able to say I knew you back then.


#4

@henryhbk – I see you making a lot of cool prototypes to solve problems of the day. I always assumed that medical gear was like airplane parts… Doesn’t matter how smart your new part is, it isn’t legal to bolt it onto an airplane (even in the galley) until it has had a bazillion dollars of tests and certifications. How does the medical field compare? Until I saw your posts I assumed that it wouldn’t be legal to just invent something and use it in an OR. There must be less regulation than I had assumed.


#5

Very cool except now the only way to remove it is to pull the wire. This then requires a second hand off so the finger controls are in the proper place in the hand to use it. Someone I know just loops the wire through one of the handles of a clamp affixed somewhere near the operating field if the holster is not strategically positioned.


#6

So this prototype will go through a whole set of revisions, then we will apply for IRB (Institutional Review Board) approval, who we will have to convince with evidence from simulations and study that the device is safe and effective, and if it’s not how will we detect that and correct problems. This week I will have my first clinical trial of a device that I will be directly 3D printing the actual device for use. I had to demonstrate a whole lot of safety tests we did, and that the individual spools of Nylon I am printing with have FDA certificates of origin, and about 50 other things. It’s routine for us to do this kind of thing.

Actually one of the biggest complaints is that in the other style that you can’t easily grab it by the cord as that often just pulls it out and down on the floor as it lets it go sideways even when it just gets snagged. Also you don’t want someone to pick it up by accident with their hand on the trigger, as they can accidentally trigger it. And most people dislike having clamps on the field (that’s a 3rd part of this project) anywhere on the drapes as they tend to snag cables and hoses and pull things to the floor. We will be extensively testing this in our simulation center OR to see how it functions.


#7

One of our Dr solves the dropped issue by being known as Dr butterfingers and just uses upwards of 4x the amount of instruments. 12 weitlanders for a vascular case. And that’s just the beginning.


#8

The problem is that you can calculate what one lost minute of OR time is worth at a busy academic hospital, and it’s expensive. The device we are hopefully starting the trial for shortly that I am 3D printing is designed to save about 10 minute in about 1 in 3 thoracic surgery cases. That’s staggering (like $200 wastage) to be able to be fixed by a “stupid piece of plastic” (as I like to call them) but it is amazing what we work around and tolerate because most people don’t have the basic tools to understand how to make something (which is also why I am core faculty on a new course for our surgical residents where they learn making over their first couple of years)


#9

on a new course for our surgical residents where they learn making over their first couple of years

This is so great! and should be a part of primary school. The general lack of problem solving skill much less basic making skills is sad. I love seeing all the things you bring to the medical field!


#10

That’s cool! (It also makes me think of the days when glassblowing was a required course for physics grad students)


#11

If you’re a doctor and it’s your own practice the rules are pretty loose. Presumably, if it’s your plane and you made a custom cup holder for the cockpit you could use it without formal certification.

Presumably Harvard’s teaching hospital isn’t henryhbk’s private clinic, so they have their rules. I’m unsure of any government rules directly addressing something like this, besides having an IRB, for them as long as they don’t sell it.

If he wanted to form a company and market it then there are various sets of rules the company would have to follow. The medical device field is based on levels of risk the device presents. At a glance the primary risks seem to relate to sterilization and no sharp edges that will tear a glove or cut an operator. Basically, the lowest level and therefore the least amount of testing. That said, the manufacturing process, especially if it is meant to be sterile (and it may not have to be), is going to have to be well documented. I would think he’d be best off, if he was interested, in investigating a design patent and licensing it to an established manufacturer.


#12

The high school I teach at has a very impressive makerspace (private school) and they start in 6th grade. They have all the toys, including laser cutters.


#13

Actually the rules are pretty uniform across the spectrum regardless of practice (and actually you can’t modify your plane anyway you want - my father and son are pilots) but you can do little things that don’t affect flight safety.

So all medical research using human subjects (regardless of payer or location) is governed under HHS federal rules, and you will need IRB approval for anything that isn’t FDA certified. And depending on the type of device you probably have to file it in clinicaltrials.gov. The primary investigator and key other personal have to be CITI certified. Now the level of IRB review (if you don’t have one you have to contract with a commercial IRB) depends on the risk as you stated. So if you are trying a new implantable device that is a very high risk and will be an extensive review, but if you are testing a new sodium assay to replace the old one, and people will get both run off the same tube, that is likely judged minimal harm, so lower level review, and if it is chart review on anonymized charts, that will likely be exempt.

Harvard’s and my hospital’s IRB are strict in the way a Prussian math teacher was… They generally err on the side of overcautious…


#14

Because everyone has a Bovie in their kitchen :slight_smile:


#15

How do you cut your steaks? What a knife? What is this 1875?


#16

No, that was the Bowie knife :smile:


#17

I was taught by the finest british stereotypes. I cut my steaks with my wit!


#18

Epic…these are things I love!! You could become an even wealthier man from such ideas…


#19

just spewed coffee…


#20

The good/bad news of being at a huge academic medical center is we have an entire staff devoted to that (whether you like it or not) and inventions get disclosed to them, and they decide whether to patent or not (but in fairness they pay all costs and defend if required, you get the patent but you immediately have to sign over to them, and your lab/division gets 33% of the revenue, inventor gets 33%, hospital 33%.