A Guide To Understanding The Various Wound Classification Systems
There are as many classification systems for wounds as there are clinicians who believe they have developed the proverbial “better mousetrap.” The various wound classification systems include the Wagner classification, the University of Texas scheme, the S(AD) SAD classification, the Red Yellow Black breakdown, which is prominent in the nursing literature, the PEDIS classification and the DEPA Score. Several questions invariably come up in a discussion of these classification systems. Does the private practitioner use any of them? Should the clinician use a classification system? If so, which one should the clinician use? Most of us use a classification system in our chart notes when describing a wound but questions still abound about which system is best. There are four main advantages of using a well-designed wound classification system in practice. A well-designed classification scheme: • provides a valuable means for organization; • represents a common language for speaking with other medical professionals; • can help with reimbursement issues; and • provides validation of chosen treatments. Emphasizing The Benefits Of Organization And A Common Language For the researcher and the private practitioner who enjoys contributing to the literature, using a classification system is imperative as it allows one to categorize similar wounds (i.e. comparing all patients with forefoot gangrene). Organization allows practitioners to retrieve information easily from large databases for comparison. Even the most efficient description appearing in chart notes, without the benefit of categorization into a classification system, makes a review of data cumbersome and unreliable. When we were residents, we were all trained to speak the common language of fractures when discussing what we were seeing in imaging studies. That common language cut through any potential confusion when discussing pathology and potential treatments. Unfortunately, the same respect is not always given to the foot wound. The physician can ensure he or she is getting the consultation that the patient requires if he or she is able to convey to other services the exact nature of the problem. Likewise with referrals, the old adage of “garbage in, garbage out,” explains the problem with inexact descriptions. Underscoring The Importance Of Using A Validated Classification System As we all know, third party payers often use clerks to make crucial decisions about a patient’s care, depending upon the symptoms, systems involved, severity and other key factors. Obviously, these clerks may only have a superficial understanding of the clinical issues involved. Using a validated classification system allows the third party payer to have access to that information. The validation of the wound classification system facilitates recognition by payers and the medical community at large because the system is verifiable. Indeed, validated classification systems have been shown to have reproducible outcomes. This leads to proven treatment protocols for the wounds in that category. With limited resources available, it is important to be able to reliably predict an outcome for any given treatment. It is also a method that will often allow a practitioner to use a cutting edge treatment to treat and cure a wound more effectively rather than utilizing an inexpensive modality to continue to treat a patient’s wound in a palliative manner for a much longer time. For example, using a validated wound classification scheme may make it easier for a clinician to use the Wound VAC® (KCI) versus saline soaked gauze. Weighing The Merits Of The Wagner System The Wagner system is the most widely recognized and utilized classification for foot wounds, and is still mentioned in the medical literature with great frequency. However, as one research group said, “The basic problem inherent to any classification system for any disease is that the ease of its application is inversely related to its clinical accuracy.”1 While the Wagner classification is a simple, easy to remember system, based upon the location and depth of ulcerations, one should be aware of the system’s limitations.2 The Wagner classification does not take the presence of neuropathy or the size of the lesion into account. Indeed, these factors can have a pronounced effect on the treatment and potential outcome. That said, here are the basic tenets of the Wagner system. Grade 0: No open lesion but may have deformity or cellulitis Grade 1: Superficial ulcer, partial or full-thickness Grade 2: Ulcer extends to ligament, tendon, joint capsule or deep fascia without abscess/osteomyelitis Grade 3: Deep ulcer with abscess, osteomyelitis or joint sepsis Grade 4: Gangrene localized to forefoot or heel Grade 5: Extensive gangrene Reviewing Other Classification Systems The descriptive “S(AD) SAD” system builds upon the Wagner classification to include several additional categories: size (area, depth), sepsis, arteriopathy and denervation.3 Developed by an English group, the S(AD) SAD classification is a validated system that was reported in Diabetic Medicine. The system, with grades 0 to 3, includes a cross-sectional area but many clinicians believe this is too complicated and may result in confusion. At the other end of the spectrum is the RYB Color Classification, which was developed for the nursing literature.4 It initially appeared in the American Journal of Nursing in 1988 and has enjoyed considerable popularity. The system relies purely on a color scheme with no additional considerations. R/Red wounds are those that exhibit pale pink to beefy red granulation tissue and are deemed to be in the inflammatory or proliferative phase. Y/Yellow wounds are marked by pale ivory, yellowish green or brown color, slough of necrotic but moist tissue, and wound exudates. B/Black wounds are marked by black, brown or tan color, and desiccated eschar. The RYB classification is an easy and widely accepted system in the nursing literature and shows the continuum from acute to chronic wounds. Conversely, it is non-specific with no consideration of depth or size, and no consideration of the contributing factor of neuropathy. PEDIS, the most august of the systems, was developed by the International Working Group on the Diabetic Foot, a primarily European group. From its beginnings, the classification was designed as a system for the specific needs of research groups. PEDIS stands for P (perfusion), E (extent/size), D (depth of tissue loss), I (infection) and S (sensation). There are levels of 1 to 4 for each of these factors. The in-depth nature of this system is appropriate for the research community that desires this amount of detail.5 What About the DEPA Scoring System? When it comes to wound classification systems, the newcomer on the block is the DEPA Scoring System, which was previewed in The Journal of Foot and Ankle Surgery (JFAS) in 2004.1 DEPA stands for D (depth of the ulcer), E (extent of bacterial colonization), P (phase of ulcer) and A (associated etiology). Ascending scores, from 1 to 3, are assigned for increasing levels of intensity in each category. For instance, an ulcer involving soft tissue receives a 2. Contamination of this ulcer receives a 1. The ulcer is in the inflammatory phase, generating a 2 score, and has an underlying bony deformity, generating another 2 score. Accordingly, this ulcer has a total score of 7. Ulcers with a total score of 6 or less are considered “low grade” ulcers. Recommended treatment measures include oral antibiotics (if infected), blood sugar control (type not specified) and debridement. Those with a total score of 7 to 9 are deemed “moderate grade” wounds that one would treat with parenteral antibiotics, insulin, debridement, healing promoting agents and pressure relieving methods. The “high grade” lesions, those with a total score between 10 to 12, require a conservative trial including parenteral antibiotics, insulin, debridement, healing promoting agents and vascular reconstruction. The authors of the classification system offered acute ischemia patients a below-knee amputation at the time of presentation, a concept that may be foreign to this country’s practitioners who will usually offer revascularization or other interventions. The scores of 11 to 12 are prognostic for amputation and if these are heel ulcers, they were even more likely to lead to amputation. Scores of 10 or greater predict difficulty with healing while scores of 6 or less indicate probable healing. Although the DEPA Scoring System is a validated system, it involved a small number of patients and a relatively short follow-up period.1 Key Insights On The University Of Texas System The University of Texas Classification of Diabetic Foot Wounds is becoming an increasingly popular system and has been validated in locations other than its original source.6 This straightforward system grades wounds first with numbers 0 to 3 referring to depth: 0 (pre- or post-ulcer with epithelialization), 1 (superficial and not involving tendon, bone or capsule), 2 (ulcer penetrates through to tendon or capsule) and 3 (penetrating to bone or joint). A second classification tier, A to D, refers to other burdens on the wound. A indicates non-infected/non-ischemic, B indicates infection, C indicates ischemia and D indicates infection plus ischemia. Clinicians may also utilize a complementary system called the Foot Risk Classification System, which was also developed at the University of Texas.7 This system allows the clinician to place the wound in an algorithm, based on its classification, that will maximize healing potential. This system allows the clinician to treat the wound based on a proven protocol that was successful for treatment of ulcers. When explaining the University of Texas (UT) wound classification system to a visitor, one UT trainee said the system was akin to using a roadmap when you are trying to get to a destination. Without the roadmap, you do not know which road to take. You have stops and starts, take wrong turns and if you do get to your destination, in this case “healing,” it is by pure luck rather than by intention. Diabetic wound healing is a complicated process that requires a definite plan based on scientific fact. A validated classification system can be the roadmap to get you there. Dr. Satterfield is a Clinical Associate Professor at the University of Texas Health Science Center at San Antonio. Dr. Steinberg (pictured) is an Assistant Professor in the Department of Plastic Surgery at the Georgetown University School of Medicine in Washington, D.C.