SLR - September 2013 - Wesley Drew Chapman
Reference: Shuler F, Bates C. Skin Temperatures Generated Following Plaster Splint Application. Orthopedics. Volume 36, Number 5, May 2013. 364-367.
Scientific Literature Review
Reviewed By: Wesley Drew Chapman, DPM
Residency Program: Grant Medical Center, Columbus, OH
Podiatric Relevance: The application of splints following foot and ankle surgery is extremely common practice. The heat generated by the exothermic reaction of the splint as it hardens can produce a thermal insult to the tissues already damaged by the surgical procedure which have the potential to lead to increased pain and wound healing issues postoperatively. All aspects of the perioperative process should be evaluated for how they may impact surgical outcomes including bandaging and splinting. Changes in technique should be made to reduce further insult to the tissues at the surgical site whenever possible.
Methods: Short leg posterior splints were applied to a non-injured extremity in a healthy volunteer in a climate-controlled room. Two splinting techniques were used, one following manufacture's protocol using eight plaster plies and cool dipping water of 23.9°C. The other technique was the current one of the investigator’s practice which included 10 plies of plaster material for increased rigidity and dipping water temp of 35°C. Also evaluated was elevation techniques of the extremity which included: on shredded urethane pillows covered in plastic and a cotton pillow case, on cotton blankets, on ice packs on cotton blankets for 30 minutes (short-term cryotherapy), or with the heel elevated on the corner of a wooden bed to permit free air circulation. A calibrated monotherm thermistor sensor was placed on the calf at the myotendinous junction and secured with fourlayers of Webril. Another sensor was placed in the splinting material. Skin and plaster temperatures were recorded at one-minute intervals until they returned to baseline (approximately 90 minutes). Seven splint applications were used to test each protocol. The maximum skin temperature achieved and the average time above 40°C or higher were reported (which corresponded with the initial onset of discomfort). Legs were alternated and the skin temperature was allowed to return to baseline between applications. Clean dipping water was used for each application.
Results: The manufacture’s protocol mean plaster temperature was 42.7±0.4°C and the mean time it was above 40°C was 22.3±0.7 minimum and a maximum temperature of 44°C. The current practice mean plaster temperature was 47.4±0.4°C and the mean time it was above 40°C was 24.9±0.5 minimum with a maximum temperature of 42°C. The elevation of the splinted extremity using pillows resulted in the highest skin temperature in both protocols, with temperatures over 40°C for 19±1 minute in both groups. Pillow elevation skin temperatures in the current practice and the manufacture’s protocol were 44.4 ±0.4°C vs 42.21±0.3°C respectively. Blanket elevation resulted in similar results with current practice temperatures of 45.4±0.5°C and manufacture’s protocol temperatures of 41.0±0.3°C. When the heel was elevated to allow air circulation, there was a significant decrease in temperatures in both the manufacture’s protocol and current practice protocol at 38.03±0.3°C and zero minutes above 40°C and 40.9±0.3°C and nine minutes above 40°C respectively. Short-term cryotherapy produced a 10°C decrease in the current practice group with the maximum skin temperature only slightly above the baseline starting temperature of 31°C.
Conclusion: Application of posterior splints should be performed per manufacture’s protocols along with elevation allowing for free air circulation or the use of short-term cryotherapy. Avoid using increased layers and warm dipping water as both increase thermal insult to the tissues. Splint elevation on pillows or blankets should also be discouraged due to the above reasons.