improvised external fixator construct

[pa4ortho]

I have been doing reasearch on historical Orthopedic surgical treatments. the goal is to look at old meathods that had adequate outcomes and use this as a base to develop improvised home made treatments. prior to this pins on wooden dowels has been described in my other posts as my best improvised ex fix its solid but is dificult to make small adjustments if its off slightly. wood can harbor infection.
the work of parkhill on external fixation devices deserves review
in 1894, published 1898 anals of surgery. I will try to describe it.
1. incision 1-2cm
2. blunt disection to bone.
3. insert tube, to bone As a drill guide. duplicate 2-4cm apart. insert guides into a, drill press made, pre drilled sterile metal or plastic block to make them parallel. use a blunt probe or spinal needle to palpate bone and ensure you drill cortex marrow cortex. don't weaken the bone by being off center. slide a wire with a small hook (bend wire 90deg, cut off leaving a tiny L shape) on the end down the hole to measure depth. use a tap to cut threads in the holes. place coarse thread stainless screws with no head in the holes to that depth + 2mm use a drill chuck with a t handel to insert by hand. don't strip the threads in the bone. duplicate the procedure on the other side of the fx for a total of 4 pins.
ok here's parkhills good stuff.
thread a nut on each shaft. place a metal plate on each screw. google to see the comma with a square tail shape parkhill used. if you used straight metal flat plates instead of parkhill's shape slot the ends to accomidate both pins and use a washer. parkhill used 4 plates in 2 parallel stacks due to the offset comma shaped head on the screws.
next place a plate with a pre drilled hole in each end perpendicular under over the stack and bolt the ends to clamp the stack together locking the construct. use plate benders to accomidate any angle between the pairs of pins. the whole plate construct can be duplicated higher up to add more rigidity.
dog bone testing is next. (ie. my dog gets the deer bones when im done with them.)
any feedback on this old school garage medicine?

pa4ortho

[Reasonable Rascal]

I have to say it because it needs to be said:

This thread is worthless without pics! :D:

RR

[pa4ortho]

you are absolutely correct how do I post a pic? i do most of this from my phone pda
pa4ortho

[Reasonable Rascal]

Best way is to use a hosting site somewhere and post the link to the pic on said site here.

RR

[pa4ortho]

google search images for (parkhill external fixator 1898) 1st image is from MD consult, a subscription service so i cant just post a link but a low res image can be found.
pa4ortho

[pa4ortho]

http://books.google.com/books?id=qLBvaM_gWvYC&pg=PA20&lpg=PA20&dq=parkhill+external+fixator+1898&source=bl&ots=2vFgFGgYXh&sig=NyEu0IomB-kfGmJFpLU21DRO93w&hl=en&ei=ppviSrSmHoS0swPjp923Aw&sa=X&oi=book_result&ct=result&resnum=9&ved=0CDAQ6AEwCA#v=onepage&q=parkhill%20external%20fixator%201898&f=false

better with article, page 20

pa4ortho

[Reasonable Rascal]

Nice find indeed.

Back in the later "70's I worked in a small hospital where one of the docs routinely used traction wires for external fixation along with skeletal traction. Pretty low tech when you think of it, required little more than a manual hand drill and sterile stainless steel wires applied through the bone and muscle 90 degrees to the limb. Traction of course followed. Any chance this might be a useful tool for the austere tricks chest?

RR

[pa4ortho]

As before this is really hard to describe but here goes. ok so i got the kit together and made some flat steel plates to bolt onto threaded K wires . plates need to be bent to be able to adapt to any divergent angle between the pins. pin guide to keep pins parallel will help with this but makes it dificult to adjust for imperfect reduction when the pins are driven. stacked plate construct seems moderately strong. not as good as comercial carbon fibre rods. better than pins in a dowel. will try aluminum plates next.
This project will be on hold for a while due to work schedule. will keep you posted as it continues. when the final project is complete I will make some photos available.

pa4ortho

[Reasonable Rascal]

Look forward to the finished product.

RR

[pa4ortho]

The final product:
improvised ex fix

must use commonly found items machinable with common shop tools found worldwide.
- my pins are a problem
must be sufficiently rigid for bone healing

must be able to manage soft tissue injuries around it and keep it clean

must be able to rotate it and bend it universally to fit.
- mine can only adjust in two of three planes once pins are placed


- I took some rectangular blocks hard lexan plastic and aluminum both worked well.
I cut them to 3/4 in high 1 1/4 in wide and 2 1/2 inches long. (The long axis runs parallel to the bone when in place.)

- I cut a 1/4 inch strip off the width of the block with a thin saw. that cut strip measures 1/4 by 3/4 by 2 1/2

-the remaining block is 1 (minus the width of the saw) by 3/4 by 2 1/2. Cut down the center of this dividing it into 2 halves. both 1/2 (minus saw cuts) by 3/4 by 2 1/2

-reassemble the cut blocks to the original shape and clamp them together in a vise.

- through the line of the first cut drill through the depth (3/4) inch with three holes spaced evenly apart. this forms the bone pin holes.

- drill a 1/2 inch diameter hole the length of the block (2 1/2) on the line of the second cut. This hold a length of common 1/2 inch EMT conduit pipe that spans the fracture.

-next remove the block from the vise and turn it 90 degrees so the cuts are parallel with the floor. drill 4 holes for small hex head bolts in each corner. these compress the assembly and don't allow the construct to move when the bolts are tightened around the pins and the pipe. You may have to sand the block a little on the cut surfaces if it does not grab the pins tight enough.

-make a second block as above.

- to apply it first place pins in the block with the hex bolts loose. Place the EMT pipe in place. reduce the fracture to final position. use the block as a guide to keep the pins parallel as you place them in the usual fashion into the bone. with one block above and one below the fracture.

- tighten the 4 hex bolts on one end. make any final reduction rotation or compression of bone and while reduced have an assist tighten the hex bolt on the other block.

-remarkably rigid due to the size of the emt pipe in a round clamp. comparable rigidity to a stryker 2 bar set up with just one EMT pipe.

-the stainless coarse thread self tapping screws were hard to find. and remain a weak link in this improv. Also no data on strength performance in bone with that screw pitch over weeks of healing. large smooth pins wont hold for long. Drill bits have the same problem plus they can snap off or corrode.

-the emt conduit pipe can be bent a bit if needed to work around something. the sharper the bend and you can start to loose some rigidity with multiple 90 deg bends so don't get too creative.

- if you use a tissue protector (a hollow pipe around the pin while drilling) you must remove the block and replace the block to get the protector out. best if you use 2 so that you only have to remove the block once.

- three holes were drilled in the block for two pins. this is so additional pin can be added later to reinforce a loose pin in the bone or to modify pin placement to fit the anatomy or wound. use the 2 holes furthest apart for best stability. Use the thickest pin practical for the bone size for best stability.

ok so everyone lost? I will try to get some pics up.

pa4ortho

[tangent]

you are absolutely correct how do I post a pic? i do most of this from my phone pda
pa4ortho

Old complaint - this kind of forum easily supports pics, vids and other things like chat rooms. :( I have been talking to you about these things for YEARS!

:(

-t