Identifying the significant risk factors associated with pressure injury development and being able to predict which individuals most at risk are considered key elements of prevention. A formal assessment is required as research has shown that clinicians tend to intervene only at the highest levels of risk when an informal risk assessment is completed (Ayello & Braden 2002; AHCRP Executive Summary #3 1992; Keast et al. 2006). Many existing risk assessment tools were designed for the general population and for this reason their predictive value is imprecise in the SCI population (Consortium for Spinal Cord Medicine 2000; Houghton et al. 2013). In fact, the 2013 Canadian Pressure injury Best Practice Guidelines go as far as to say that many existing tools have not been validated for use in the SCI population and “may [in fact] not perform better than clinical judgement” (Houghton et al. 2013).
A review of pressure injury risk assessment scales used with the SCI population was conducted by Mortensen and Miller (2008). Findings indicated that the SCIPUS (Salzberg et al. 1996) and SCIPUS-A (Salzberg et al. 1999), while developed specifically for the SCI population, are not yet recommendable for use without further psychometric testing. The Braden scale (Bergstrom et al. 1987) seems to be the best tool available thus far, without being well validated for the SCI population. There is adequate correlation of both the Braden and the SCIPUS scales with determining the stage of the first pressure injury and of the number of pressure injuries (Salzberg et al. 1996; Salzerg et al. 1999; Wellard et al. 2000; Ash et al. 2002). Individuals with severe and moderate Braden scores are 2.36 and 1.82 more likely to develop pressure injuries respectively than those with mild scores (Fazel et al. 2018). There is no evidence supporting responsiveness for the Braden (Wellard et al. 2000) or SCIPUS over multiple assessments in the SCI population. Furthermore, the Braden scale exhibits a ceiling effect when used in the SCI population (Wellard et al. 2000); ceiling effects have not yet been reported on for SCIPUS. Scovil et al. (2014) reported that perceived non-specificity to the SCI population led to low Braden completion rates (29%) and subsequent piloting of SCIPUS implementation. Psychometric properties of SCIPUS compared to Braden are anticipated from this group.
Another review of pressure injury healing assessment instruments was completed by van Lis et al. (2010). Of the eleven instruments reviewed, only two instruments had enough psychometric data to be considered useful and promising for use in the SCI population. The “ruler length and width” method was found to have good intra-rater and inter-rater reliability and concurrent validity. The Sessing scale was found to have moderate concurrent validity (van Lis et al. 2010).
The reliability of single wound assessment tools in SCI has also been evaluated by several investigators (Van Asbeck and Post 2015; Arora et al. 2017). Wound length, width, depth and undermining using a Decu-Stick has shown to have excellent positive and negative predictive values indicative of healing (van Asbeck and Post 2015). Additionally, the sum of four measurements of undermining using four cardinal points of a clock were shown to have excellent intra-rater and inter-rater reliability (Arora et al. 2017).
Detailed analyses of SCI-specific psychometric properties for a variety of skin health assessment tools is available in SCIRE Outcome Measures (e.g., search alphabetically or by clinical area). Below we will discuss the potential of new tools for diagnosis and assessment of pressure injuries for the SCI population. Simple, reliable tools to regularly and consistently assess a person’s disposition for pressure injury development are much needed.
Summarized Level 5 Evidence Studies
An observational feasibility study to pilot this device was conducted on a group of 34 United States veterans with SCI. The device was found to be feasible but requiring a larger scale study to determine optimal frequency of use and threshold differences for various high risk locations on the body of those with SCI (Guihan et al. 2012). Krishnan et al. (2016) found differences in urine and plasma biomarkers for individuals who developed pressure injuries. The expertise and time required for analysis to make use of this method may impose feasibility issues.
A new non-invasive and practical handheld dermal phase meter is reported to detect increased sub-epidermal moisture and therefore predict the appearance of stage one pressure injuries in the following week as was shown with a small group of predominantly female nursing home residents prevalent with urinary incontinence issues (Bates-Jensen et al. 2007). In a separate study, subepidermal moisture, captured by a hand-held MoistureMeter-D was measured in 16 veterans with Stages 3 or 4 sacral or ischial pressure injuries (Harrow and Mayrovitz 2014). Increased subepidermal moisture was found in areas of pressure injuries when compared with intact skin (Harrow and Mayrovitz 2014).
Another method that can be used to detect early deep tissue dermal edema is high frequency ultrasonography. Using this technology in a non-randomized study with a blinded assessor, Kanno et al. (2009) demonstrated that ultrasonography was a useful tool for the early detection of deep tissue injuries or pressure injuries. While the presence of low-echoic lesions were detected under both wounded (e.g., red or free floating) and normal skin detected by inspection and palpation, the absence of low-echoic lesions in the presence of inspection and/or palpation findings never occurred.
Magnetic resonance imaging (MRI) has become more common as a tool to visualize soft tissue pathology and therefore more important in the diagnosis and management of pressure injuries in individuals with SCI. When 37 SCI patients with an indication of pressure injury underwent MRI scans (de Heredia et al. 2012), acute cortical bone erosion and abnormal marrow edema accurately predicted osteomyelitis, with strong intra-observer agreement (Hauptfleish et al. 2013). Given that osteomyelitis often follows non-healing pressure injuries, MRIs can be a useful tool to expedite the treatment considerations for pressure injuries and avoid devastating sequelae such as osteomyelitis.
Circulatory biomarkers for muscle damage have been proposed as an indicator of deep tissue injury in pressure injury development after SCI and in pressure injury development (Krishnan et al. 2016). Loerakker et al. (2012), in a small study (N=8) comparing muscle damage biomarkers, did not find differences between groups of able-bodied and SCI subjects.
There is level 2 evidence (from one prospective controlled trial: Kanno et al. 2009) that supports the use of ultrasonography to extend the yield of routine inspection and palpation of suspected or early stage pressure injuries in people with SCI.
There is level 3 evidence (from one case control study: de Heredia et al. 2012) that magnetic resonance imaging can predict the development of osteomyelitis in non-healing pelvic pressure injuries in patients.
There is level 4 (from one case series study: Loerakker et al. 2012) that reliance on circulatory biomarkers as an indication of muscle damage secondary to deep tissue injury in the SCI population cannot be recommended at this time.