The physical characteristics of a scar are determinate of how that scar may function physiologically and mechanically. These characteristics as defined below offer vital clues to how the scar will serve in its role as repaired skin. For example, a lack of pliability will reduce the flexibility of the scar, and loss of tissue and scar contractures can lead to reduced range of motion. Assessing for these attributes may help to predict behavior and track the course of treatment (see Chapter 19).
Surface Texture (Profilometry22)
The surface texture (relief) of a scar refers to irregularities and “lumpiness/bumpiness” when compared with normal skin.23 For example, Figure 5-9 demonstrates the chest and shoulders of a woman after an extensive burn. The surfaces of these scars are highly variable and demonstrate many contour irregularities. Optical and mechanical profilometers are available to provide objective measurements, but are used more commonly for cosmetic evaluations than for scar evaluations at this time.22
FIGURE 5-8 A: Clinical dermatoscopic image of a hypertrophic scar of the forearm. B: Confocal microscopy of the same hypertrophic scar on the forearm imaged at 152.40 μm below the stratum corneum. Collagen fibers and bundles (red arrow) are present within the hypertrophic scar; however, there is no collagen noted at that depth in the surrounding normal skin.
Surface Area (Planimetry22)
This refers to the area the scar occupies in relation to the original wound size, and can be larger or smaller than the initial wound.23 This can be assessed with simple dimensions to derive a surface area. However, more objective measures have been used in clinical studies because of the varying contours of the underlying normal and posttraumatic anatomy. More commonly, the margins have been traced on clear plastic
film or grid paper, or have been photographed. For more extensive scars, such as burn scars, it may also be appropriate to quantify the scar as a percentage of total body surface area.
FIGURE 5-9 Clinical picture of a burn patient. Extensive burns on the chest, neck, and bilateral arms in this middle- age woman
Thickness/Height
The thickness and height of a scar is related to the scar’s degree of hypertrophy. It is defined as the distance between the subcutaneous–dermal junction and epidermal surface of the scar.23 One can measure the height of the scar from the epidermal surface of the surrounding normal skin to that of the scar; however, this will not account for the dermal component. Ultrasonography provides an accurate, reproducible, and objective method for measuring scar thickness. It also has the advantages of being noninvasive and relatively inexpensive.24 It does have limitations, as do all imaging modalities. For example, it has limited specificity in evaluating thin lesions and lesions with surrounding inflammation. Fortunately, these limitations are not as applicable to the ultrasonographic evaluation of scars.25 Scar thickness and height can vary tremendously based on genetic predispositions, medical conditions, and type and extent of injury.
Pliability
By definition, pliability refers to the quality of being easily bent or flexible. When pertaining to scars, it encompasses both morphologic and physiologic properties, and the pliability of a scar is crucial to its functional performance. Pliability can be evaluated grossly by assessing the range of motion over an affected joint, or by stretching the scar between two fingers.26 A goniometer can be used to assess the maximum degree of extension or flexion prior to therapy. A relatively pliable scar will have a degree of stretch that is comparable to that of normal skin. Several tools have been developed to objectively assess this characteristic. These include the pneumatonometer,27 cutometer,24 and the cicatronometer.28 The pneumatonometer was derived from ocular tonometry. It uses similar principles to detect the pliability of a scar, measuring the flow and pressure of air in the instrument after applying pressure on
the area of interest.27 Fong et al.24 used a cutometer to measure the pliability of burn scars. A cutometer uses gentle suction to measure the viscoelasticity of a scar. The cicatronometer is a form of a handheld tonometer. It has a loaded spring with an indicator rod attached. When applied vertically to the skin, the indicator rod is depressed to a certain degree; the further the depression, the firmer the scar.28
Color
The color of a scar comprises both its pigmentation and its vascularity. When assessing scars, it is important to make the distinction between the two components. As previously mentioned, the vascularity of a scar is highly associated with the age of the lesion. Earlier scars are more vascular, whereas mature nonpathologic scars eventually reach the vascularity of normal, uninjured skin. Therefore, the clinical appearance of erythema of a nonpathologic scar will subside as its vascularity normalizes over time.1 Diascopy, or blanching of the vessels with a transparent device by applying gentle pressure, is a simple and effective way of assessing the vascularity of a scar. It also aids in eliminating the effects of vascularity when assessing the scar’s pigmentation.29 Colorimetry can also objectively assess measures of vascularity and pigmentation in the skin. A colorimeter is a device that analyzes color by measuring it in terms of a standard color, a color scale, or certain primary colors. Jones’ review found high concurrent reliability, validity, and reproducibility of colorimeters in assessing vascularity; however, they fell short with pigmentation assessment as compared with the visual scoring systems.30 Draijers et al. discovered that colorimeters produced much higher reliability in pigmentation assessment as compared with a single observer. Three observers were necessary to achieve adequate pigmentation assessment in comparison to the colorimeter. When assessing vascularity, a single observer could reliably assess the scar in comparison to the colorimeter.31 Based on these studies, colorimeters may be particularly useful in evaluating pigmentation since this can be challenging (even for trained observers). On histologic examination, both vascularity and the pigmentation can be appreciated. For example, Travis et al.13 discovered an increased amount of melanin, α-MSH, and stimulated melanocytes in hyperpigmented hypertrophic scars in comparison to hypopigmented hypertrophic scars, whereas there was no statistically significant difference in the number of melanocytes.
Appearance
A focus on individual characteristics such as color or elevation reveals little about the overall impact of a scar upon a patient’s quality of life. A biopsychosocial approach is more informative, considering scar biology in the context of the patient’s needs and expectations in their individual and social environment (see Chapter 24). For example, where is the scar located? Does it adhere to the cosmetic contours and relaxed skin tension lines? Does the scar cause any cosmetic disfigurement or loss of function? Is it located in a particularly relevant area for the patient and his/her background? Are there particularly negative associations surrounding the inciting trauma? These are all
essential factors to consider with scar assessment, as cosmetically defective and functionally inhibitive scars can lead to significant psychological as well as physical distress.
Symptoms
Arguably, one of the most important aspects of a patient’s scar is how it impacts him/her, if at all. The two most common symptoms related to scars are pruritus and pain. In a study by Van Loey et al.,32 itch was rated to be one of the most important factors in a patient’s assessment of his/her own scar. Other common symptoms to assess for include pain, pulling, heaviness, tightness, pinching, achiness, and tenderness. Underestimating the subjective symptoms in these patients may be detrimental to their psychological as well as physical health, and perhaps lead to undertreatment. It is well documented that the symptoms a patient may experience in their scars can lead to lasting and significant psychosocial impairments (see Chapter 11).33,34