In this blog, we are going to look at how to make a non-waterproof fibreglass cast, using soffban as an undercast. This cast would be made for someone with a distal radius fracture or maybe a carpal bone fracture. Following is a step by step guide to help you out.
Firstly you will need a piece of stockinette. Cut a very small hole for the thumb, because it will stretch and leave enough on each end to be folded over. So put the stockinette on the patient’s hand and put their thumb through the hole.
The next thing we need is a soffban. We usually go a couple of times around the wrist, so you want to wind it away from yourself and then up through the webspace, just tearing it a little bit. I usually go through the webspace three times. The trick with the soffban underneath is you don’t want layers and layers and layers of it because it’ll bottom out and then your cast will be too loose. So you wind it down the arm, again winding it away from yourself. You want it to be the same as when making a thermoplastic splint: about two-thirds the length of the forearm.
From here, just tear off what you don’t need as you won’t need to use the whole roll. Then with your stockinette, fold it so you’ve got a nice smooth edge over the hand. Just make sure that you’ve got enough room around the thenar eminence and clearing the distal palmar crease.
For this step, we’re going to open up our Delta-Cast fibreglass. Make sure that you are wearing gloves because the fibreglass will stick to your hands. You also need a pair of scissors that can withstand getting fibreglass on them, so don’t use good scissors. You can use disposable scissors if need be.
As we do this, it’s important to understand that we’re not trying to manipulate a fracture or anything like that. We should only be doing this on non-displaced stable fractures. So we’re just going to make the cast in a neutral position.
In most orthopaedic clinics that do lots of casts, they’ll dip the fibreglass in water to make it go off quicker. However, I recommend not to dip it in water because it gives you longer working time. So from here, what we do is go two or three times around the wrist and up through the webspace. This is where we cut the material through your webspace, and then just catch those two ends. Go around the wrist again and then up through the webspace. This is done three times and on the third time, fold each end so it looks nice and neat.
Then all you have to do is just wind it down the arm, overlapping by about a third each time. The trick with fibreglass is not to pull it too tight, just wrap it how it unwinds, and then the cast won’t be too tight. So just cut it off where you need it and then it’ll stick to itself there.
Now the trick is to get some moisturiser or sorbolene onto your gloves, and pat down the edge near the bottom so it sticks, and then start moulding into the palm, making sure we’ve got lots of room around the thumb and no sharp areas.
As the fibreglass is going off, you should have a nice edge and no sharp edges around the thenar eminence, as you are moulding it in a neutral position. You’re not really looking to put the wrist in extension or flexion but you do need the patient to be able to make a fist, and touch their thumb to each fingertip.
It’s also important to make sure that you don’t deviate the wrist, so make sure you check this as you are moulding the cast.
From there it takes about 10 minutes to set so you can ask the patient to wait in the waiting room for 10 minutes while you do your notes and wait for the fibreglass to become a bit harder.
If you have a stable fracture in your hand or wrist and need advice from a qualified therapist, please call us at Melbourne Hand Therapy today (03) 9899 8490 or leave an enquiry and we will get back to you as soon as possible.