Seth Snowden is an Advanced Wound Specialist working with Wound Care Plus, LLC in the Greater Springfield, Missouri area. As a part of the Wound Care Plus team, he was the first wound care specialist to apply a total contact cast in the long-term care setting. Seth has almost fifteen years of diverse nursing experience and brings that wealth of knowledge to each individual he sees. He understands how chronic wounds can be a thief of joy, energy, time, comfort, and money, therefore, he is passionate about being able to assist or guide people through the resolution and lifting of that burden. Seth loves that each week through measurements, pictures, and response of the client, it is possible to see mountains moved or perhaps caverns be filled, and how amazing it feels to be a part of that process.
Inching Forward in Wound Measurement
09/02/2020
Some disciplines in healthcare appear to be more physical than others. There are some areas of practice in which things are simply more tangible, hands on, and measurable. Wound care is one such wonderfully tactile specialty within the field of medicine. Each patient encounter involves the assessment, evaluation, and treatment of an individual’s wound/area of concern. Elements to wound assessment are wound location, anatomical structures, undermining or tunneling, tissue identification, exudate, odor, pain, periwound, and measurement.1 It is encouraging and beneficial to see improvement in any of these variables and should be documented and taken into account when formulating a treatment plan.2 However, of these, only wound measurement has been shown to be predictive of wound healing and integral to monitoring wound progression.3-5
Measurement of a wound’s size is needed for evaluating the effectiveness of current treatments and monitoring the healing process.4 The summary of research reveals that the percentage of area reduction is perhaps the most important parameter in predicting healing rates.3 A 40% reduction of ulcer area after 4 weeks of treatment has been shown to have favorable prediction of wound healing.6 Khoo and Jansen7 suggest a reduction in wound area of 20% to 40% after 2 to 4 weeks is an accurate predictor of wound resolution. Additional work similarly conveyed that the percentage of reduction in wound size after 2 to 4 weeks of treatment is a statistically significant predictor of healing.5
Measurement Techniques, Methods, and Modalities
- Linear/Clock/Ruler Measurement Technique: This is the most widely available, easy-to-perform, and very inexpensive option. A ruler, usually made of paper and disposable, is used to measure the greatest length, head to toe, or 12-6 o’clock; as well as the wound’s greatest width, side to side, or 9-3 o’clock. Measurements should be in centimeters. By multiplying these values together, wound surface area can be calculated. Identified flaws to this method are overestimation of wound area in all but perfectly square-shaped wounds and potential for wound contamination from contact with the ruler.4,8 Efforts to correct this known overestimation have been made by using mathematical models that, through the use of formulas, estimate the surface area for an elliptical-shaped wound.4
- Planimetry/Tracing Method: Manual planimetry is inexpensive and widely available; this method utilizes a clear acetate film to cover the wound. It then uses a writing utensil to outline the wound. Next, the wound sketch is placed over a grid and the squares are counted to calculate the surface area.4 Typically, in digital planimetry, clear film is placed over a digital device and retraced, capturing the wound specifications and calculating the surface area, though non-contact options have become increasingly available.7,9 Planimetry, especially digital planimetry, is considered to be very accurate, easy to use, and repeatable; however, it is time consuming, has the greatest risk for contamination, and the software can be expensive.4,8
As an adjunct to previously mentioned methods, measurement of depth and potential undermining or tunneling are valuable to gauge progress as well as for calculating volumetric measurements. Typically, this is accomplished by placing the end of a cotton-tipped or other applicator to the point of greatest depth and marking the place along the applicator shaft that is even with the wound margin, and then placed at 0 on the end of a ruler, allowing for the tip of the applicator to reveal the depth measurement. If tunneling or undermining is present, then measurement of direction and depth should be accomplished by recording the maximum distance of tracking in the direction along the clock plane described above.10
Photography also has been an increasing addition to wound measurement documentation. Pictures add a level of imaging that other documentation cannot attain. It can be useful in identification of changes in tissue quality, shape, periwound, appearance of drainage, and size. However, pictures are not as beneficial without a ruler or other reference point to provide scale to the image.8
- Stereophotogrammetry (SPG): This method of measurement involves taking wound pictures from a series of angles to create a 2D or 3D image using computer software.9 Some versions operate more similarly to non-contact digital planimetry in which the wound is traced on the screen of a computer after taking a picture. SPG has proven to produce highly accurate measurements, but typically comes with the baggage of bulky, expensive, time-consuming equipment.4
- Digital Imaging: Another promising method of wound measurement is digital imaging. In this strategy, a picture is taken and transferred to a computer where the wound margins are traced on the screen with a stylus. The software utilizes a scale adjacent to the wound to assist in calculating the area.4 Benefits of this method are its non-contact process and excellent accuracy; however, it is often time-consuming and can be compromised by variables such as lighting, camera angles, wound size, and wound location.4
- Volumetric/3D Imaging: This form of imaging involves high-resolution digital cameras used in conjunction with SPG systems that are able to take two images and connect to a computer software that would provide a 3D reconstruction of the wound.11 Structured light approaches use lasers or infrared strips of light to create a 3D topographical map of the wound.9 The image appears on a mobile device where the wound margins are traced and the software computes wound area and volume measurements.7 Another novel approach described by Barone et al12 was a device that utilized a 3D optical scanner based on structured light that had integrated a thermal scanner capable of identifying inflammation in addition to calculating wound size. Although capable of producing potentially valuable 3D and including volumetric measurements, most are impractical due too expense, complexity, and sometimes immobile devices with poorer accuracy and reliability track records compared with other options.4
In conclusion, there are many different ways to go about measuring wounds. New technologies, such as digital planimetry and digital imaging techniques, are being developed and are now available that can be more accurate, reliable, and uncomplicated use, and they provide noncontact approaches to wound measurements. However, the classic linear/ruler and manual planimetry methods offer inexpensive, easy-to-use, fairly accurate, repeatable options that typically take less time as well; since the greatest known predictor of wound healing is the percentage reduction in wound area over a 2- to 4-week timeframe, the most important factor will be consistency of wound measurement. Since all wound measurement options have their setbacks, selecting an option that is consistent and repeatable is possibly the most important factor.
References
1. Elements of assessing a wound. Advanced Tissue. Published July 30, 2014. Accessed August 1, 2020. https://advancedtissue.com/2014/07/elements-assessing-wound/
2. ConvaTec. SOLUTIONS(R) wound care algorithm. Rockville, MD: National Guideline Clearinghouse, Agency for Healthcare Research and Quality; 2008.
3. Flanagan M. Improving accuracy of wound measurement in clinical practice. Ostomy Wound Manage. 2003;49(10):28–40.
4. Jorgenson LB, Sorensen JA, Jemec GBE, Yderstraede KB. Methods to assess area and volume of wounds- a systematic review. Int Wound J. 2015;13(4). doi:10.1111/iwj.12472
5. Van Rijswijk L. Wound wise: measuring wounds to improve outcomes. 2013;113(8):60–61.
6. Flanagan M. Wound measurement: can it help us to monitor progression to healing? J Wound Care. 2003;12(5):189–194. doi:10.12968/jowc.2003.12.5.26493
7. Khoo R, Jansen S. The evolving field of wound measurement techniques: a literature review. Wounds. 2016;28(6):175–181.
8. Nichols E. Wound assessment part 1: how to measure a wound. Wound Essentials. 2015;10(2):51–53. https//www.wounds-uk.com/download/resource/1285
9. Anghel EL, Kumar A, Bigham TE, et al. The reliability of a novel mobile 3-dimensional wound measurement device. Wounds. 2016;28(11):379–386
10. Morgan N. Measuring wounds. Wound Care Advisor. Published July 11, 2012. Accessed August 1, 2020. https://woundcareadvisor.com/measuring-wounds/
11. Wunderlich RP, Peters EJ, Armstrong DG, Lavery LA. Reliability of digital videometry and acetate tracing in measuring the surface area of cutaneous wounds. Diabetes Res Clin Pract. 2000;49(2–3):87–92. doi:10.1016/S0168-8227(00)00145-5
12. Barone S, Paoli A, Razionale AV. Assessment of chronic wounds by three-dimensional optical imaging based on integrating geometrical, chromatic, and thermal data. Proc Inst Mech Eng H. 2011;225(2):181–193. doi:10.1243/09544119JEIM705
