Adventures in Serial Casting, Part I

Image from BBC

I recently worked on serial casts for a patient with brain injury to improve PROM and tone of the ankle. Here is the case study which will be followed by an entry of some of my own research into the topic.

Pt. is a ~60 y.o. female s/p multiple CVAs who was referred to OT for splinting assessment while in the neuro ICU. Pt. was connected to typical ICU monitors plus arterial line, was breathing comfortably on room air. She presents at a Rancho 3-4 level, depending on the day. Her L foot demonstrates increased tone, plantarflexion, and inversion. I was not able to passively stretch her ankle into neutral position and she demonstrated no AROM. I did not splint her per normal protocols (pre-fabricated multi-podus boot or individualized foot boot constructed from splinting material and cushioning as necessary) because I worried that she would not fit well into even an individualized splint due to the inversion and would be at risk for skin breakdown. I asked the doctors to consult PM&R at rounds, and the PM&R doctor injected the patient with a phenol nerve block (I'm not going to go into the differences between phenol and botox because I really don't know anything about it and that decision lies outside the OT realm. There is research on it if you're interested) which he said would be effective for 2-3 months.

After the nerve block, I was able to range pt's foot out of extreme inversion but not quite to neutral and she still had deficits in dorsiflexion PROM. At this time we were able to begin serial casting of the ankle. I can't say that I had experience with the specific technique, my previous casting experiences involved the elbow (in retrospect, this is much easier to cast in my opinion). However, I did take an athletic training class back in high school which involved many sessions of ankle taping (and after spraining my own ankle I got several years of experience taping my own ankle daily) so I did feel that I had a good concept of the necessary design (stirrups, figure 8s, heel locks and a general circumferential wrap).

Our first cast was applied after 15 minutes of a heat pack. Pt. was positioned on her non-affected side with L knee in flexion and L great toe in extension to inhibit tone and allow for the PT to get best stretch from her ankle. Gel pads were applied to bony prominences, cast padding was applied to the whole lower leg, and 3 layers of plaster were applied. This first cast was applied on a Friday, (only because I was on day 2 of 8 working days and would be there over the weekend to monitor) and removed on Monday with gains in PROM noted. I had forgotten the confidence that you need to operate a cast saw, but it came back. Her inversion problem was gone after this first cast. A second cast was applied on Monday afternoon and removed the following Friday by another therapist who decided to try out a standard multipodus boot at this time as the pt. could be ranged to neutral. However, when I saw her on Sunday, she still had the PROM to get to neutral but her increased tone was still pushing her into plantarflexion and thus she was pushing herself out of the boot.

We decided to do 1 additional cast in attempt to reduce the spasticity, but something was not right about this attempt. When following up the next day, there was an indentation on the medial portion of the leg that was concerning for increased pressure, and it was unreachable by tools to attempt to correct, so it had to be cut off. It still seemed wet, and I don't know why, but that made it harder to cut. I bivalved it in the hope that I would be able to fix it from the inside and make a long term splint. This was my last day before vacation and afterward they tried kinesiotaping to reduce tone as well but I was not present for that part. Thus ends the chronicle of the serial casting.

(Please stay tuned for an entry focusing on the research behind serial casting)