OVERVIEW: Clinicians agree that sustained pressure greater than 32 mmHg can cause irreversible skin damage in as little as two hours.1 Manufacturers of cervical orthoses must consider these parameters in their selection of padding materials, since the effectiveness of the padding can influence pressure at the skin surface.
Research sugggests that when properly fitted, both the Miami J® Cervical Collar and the Aspen® Cervical Collar generate a maximum average pressure of less than 25 mmHg.2 While this is below the capillary closing pressure of healthy tissue, not all patients have healthy tissue.
In this report, the cushioning characteristics of the padding material used in the Aspen® Collar and the Miami J® Collar are evaluated. The results demonstrate that at pressures of ~25 mmHg the foam used in the Aspen® pads provides cushioning that is approximately twice as effective as the pads used in the Miami J® Collar.
MATERIALS & METHODS: Replacement pads were obtained from currently available Aspen® and Miami J® Cervical Collars. Analysis showed that the Miami J® pads are manufactured from a "non-clickable" foam with a density of 1.6 lbs. "Non-clickable" foam does not readily spring back after it is die cut, so the edges appear to be sealed. Aspen® pads are manufactured from 1.6 lbs foam that is "clickable." Clickable foam is desigend to have superior resilency so that edges do spring back and do not stay compressed after it is die cut.3
The thickness of each pad was measured. A 1 Kg weight, fitted with a base plate designed to yield a pressure of ~25 mmHg was pressed into both pads and allowed to rebound. After 60 seconds, with the weight in place, the thickness of each pad was again measured.
RESULTS: The Miami J® pad averaged an initial, uncompressed thickness of .4015 inches and showed an average compressed thickness of .1860 inches after 60 seconds. The Aspen® pad had an average, uncompressed thickness of .4280 inches and rebounded to an average compressed thickness of .3180 after 60 seconds.
DISCUSSION: While the Aspen® padding rebounded to 75% of its original cushioning height, the Miami J® padding rebounded to less than half (46%) of its original height. These differences in performance may explain why using Aspen® Cervical Collars, in conjunction with comprehensive protocols, can significantly reduce the incidence of skin breakdown commonly seen when other cervical collars are used.4,5
CONCLUSIONS: The results of this evaluation demonstrate that there are clear differences in the cushioning ability of the pads used in the Miami J® and Aspen® Collars. The clickable foam used in Aspen® Cervical Collars offers superior cushioning to the non-clickable foam used in Miami J® Collars. The padding material used in Miami J® Collars lost significantly below capillary closing pressure.
ACKNOWLEDGMENT: This report data was generated by Orange County Materials Test Laboratories, Anaheim, California.
REFERENCES
1. Kosiak M: Etiology of decubitus ulcers. Archives of Physical Medicine and Rehabilitation 42:19, 1961.
2. Plaisier, B., Gabram, S.G., Schwartz, R.J., and Jacobs, I.M. "Prospective Evaluation of Craniofacial Pressure in Four Different Cervical Orthoses."
Journal of Trauma 37 (1994):714-720.
3. Foamex Report
4. Powers, Jan. "A Multidisciplinary Approach to Occipital Pressure Ulcers Related to Cervical Collars." Journal of Nursing Care Quality 1997;12(1), 46-52.
5. Blaylock, Barbara. "Solving the Problem of Pressure Ulcers Resulting from Cervical Collar: A Step-by-Step Approach" Ostomy Wound Management.
May 1996;42(4):26-33.