Two points I wanted to clarify based on some great feedback here:

1. My last post is not recommending that lido with epi be used – plain old lidocaine is much more easy to manage and use safely. Rather, lido with epi is not a one way trip to losing your finger, as it often is regarded as in the dogma of biohacking – while it should be treated cautiously, it is not necessarily contraindicated for digital work.
2. Lidocaine with epinephrine provides its own hemostasis, and its use makes tourniquets unnecessary. Using a tourniquet AND lidocaine with epi, or some other hemostatic method, can indeed lead to ischemia as evidenced by issues other magnet implantees have had — no reason to mess with something that works just fine without epi.

As I finished up a long day of finals studying, I thought I’d compile and post some information I’ve learned during my research on digital surgery in preparation for both my own surgery and for general interest.

Digital Blocks

Lidocaine is administered in the form of a digital block for a variety of procedures on the fingers. There are a few types of digital blocks, the most effective seeming to be the transthecal block, which involves an injection of anesthesia into the flexor tendon sheath (this can lead to injection site pain, so appears to be less favorable). Another, slightly easier method is a web block, which injects anesthetic into the web space near the MCP joint – others’ and my method of choice for magnet insertion.

Lido + Epi

Digital block methods have been the subject of some controversy regarding lidocaine with epinephrine. Lidocaine is potentiated by epinephrine, both in terms of effective pain dampening properties and in duration. Unfortunately, epinephrine is a vasoconstrictor, and in the case of the digits of the hand, there is a major concern that the epinephrine can cause constriction to the point of digital ischemia, leading to gangrene issues, necrosis, etc… Not a pretty picture.

However, recent studies have refuted this.

It’s really hard to be a 19 year old and be active in the development community.

It’s not because it’s hard to learn – on the contrary, I’ve found more educational opportunities in development than any hobby I’ve had. There are so many developers keen to train a young, green dev in the methodology that they’ve experienced to be the best. However, it’s that eagerness to teach and correct that can make it difficult. As I read through a subreddit on development, I find articles that hail Node.js as the second coming right next to articles that break down every single way that it is the worst possible piece of horror to ever be run.

I’ve got finals for the next two weeks, and magnet implant plans are on hold until I’m at home… stay tuned!

One of my previous Arduino projects was an Engineering 1 final project where we had to receive a small foam ball into a box 24″x12″x12″, then launch it into the next box that is immediately next to ours. Our plan began with a spring loaded catapult system that quickly proved to be unwieldy. Due to other finals going on at the time, it was only days before the competition (the result of which, by the way, determined 50% of our class grade) that we scrapped our old plan, and came up with a new one.

I busted out the shapelock and made the first of a number of prototypes for the socket that will be my magnet implant computer interface. the general design I’m planning for is a full finger socket, most likely to the metacarpophalangeal joint. It will have a small amount wiggle room for the tip of my finger bu otherwise be a snug fit. The inductor coil will be embedded in a groove in the plastic, and the magnetometer will fit in a dent in the bottom. I’m considering a fabric sleeve to hide the wires and keep things from getting snagged.

I attempted magnet insertion myself and went at it with a friend all scrubbed up to assist. Unfortunately, my scalpel wasn’t shaped correctly (#10) to make a deep enough pocket without making a massively oversized incision, and the lidocaine was wearing off by the time I tried using the tip of my surgical scissors to open a pocket, which created a triangular shaped opening that didn’t fit the magnet well anyway. I had it big enough for the magnet to fit but it barely peeked through the wound, and there was no way to stitch it so I called it off.

These two are the guts of my interface plans:

Arduino Leonardo

The Arduino Leonardo is an awesome board. It’s quite similar to the Arduino Uno, which I’m quite experienced with, but the biggest difference (and reason I’m getting it) is that it can emulate HID’s in Windows, meaning it can trigger mouse movement/click events, as well as keyboard input. I plan to either directly map it to a mouse, or have different measurements trigger innocuous keystrokes that can be picked up in the background by something like vJoy and mapped to joystick inputs.

Prepping for magnet implant surgery tonight!!

Today I took my first stab at coding some general magnetic detection code that will work with a magnetometer to detect finger presence, finder flexion, and finger extension, all based on magnet proximity to make a magnet HID. I haven’t even received my magnetometer or Leonardo yet (the Uno doesn’t support HID emulation), so I’m sure this code won’t work in practice, but it compiles and I’ll use it as a v. 0.01 for future enhancements. My only two concerns are finding a sweet spot for the finger to rest (perhaps foam above the magnetometer?), and saturation of the Hall effect chip the magnetometer runs on, but I’ll jump off that cliff when I come to it.