A pain scale is often used to help assess pain severity associated with an injury, disease or surgical procedure. You may wonder which scale is best to use when evaluating an employee’s response to a work-related injury, including non-specific muscle or joint pain.

There are many types of pain scales. Commonly used scales include numerical, face, visual analog and verbal. There are also more comprehensive pain-scoring methods.

At WorkCare, where our Incident Intervention clinicians evaluate thousands of non-emergency work-related injuries a year, we know that the way physical discomfort is evaluated and managed at onset can make a significant difference in the outcome. Each employee’s initial pain experience is shaped by a myriad of biomedical, psychosocial (e.g., belief system, expectations, mood) and behavioral factors.

For example, two similar employees with the same job and similar injuries may have notably different perceptions of pain. In this scenario, assume each employee receives the same information from a WorkCare occupational clinician about the nature of their injury and expectations for recovery. These two employees may either choose clinician-guided self-care/first aid and remain at work or elect to be referred to an offsite clinic for follow-up. An employee who perceives pain as temporary and manageable is more likely to remain at work while recovering than an employee who reports intense pain and fears that working could make the injury and pain worse.

When an injury does not quickly resolve and transitions from acute, to sub-acute, to chronic, related pain becomes particularly difficult to resolve. Chronic pain syndrome has been described as “a constellation of related symptoms and conditions that usually do not respond to the medical model of care,” and complex regional pain syndrome, which involves prolonged pain and inflammation following injury to an arm or leg, as a “biopsychosocial challenge.”

Asking Questions

Context is needed for an evaluating clinician to get a clear sense of an employee’s pain. In some cases, a clinician might ask an injured employee to remember the worst pain he or she has ever experienced in comparison with their current pain. The provider can then use that information to assess the effectiveness of interventions and pace of recovery.

When a WorkCare occupational clinician asks an injured employee to rate their degree of pain on a scale of 0-10 during an Incident Intervention telehealth triage call, they may ask other questions, as well, because they know pain is a subjective experience. For instance:

• Have you had pain other than everyday kind of pain during the past three days?
• How does the pain you have now affect you physically and mentally?
• Has the pain made you change your activity level?

In addition, when an injured employee remains at work in a full or modified duty capacity during recovery, a WorkCare nurse will check in and see how they are feeling, whether their pain has decreased, stayed the same or gotten worse, and assess any other physical or psychological aspects of their pain that may be affecting their work.

Types of Pain Scales

Pain scales are often categorized as numerical, visual analog or categorical. A numerical rating scale is commonly used to assess physical pain on a continuum of 0-10, 11-item (counting 0) scale, with 0 no pain and 10 severe pain. Some scales, such as the widely used Wong-Baker FACES^® Pain Rating Scale, features numbers as well as faces with expressions and descriptions so children and adults can choose the face that best illustrates their pain:

A visual analog scale (VAS) is a horizontal or vertical line anchored by two verbal descriptors: “no pain” (score of 0) and “worst pain possible.” The VAS is used to measure a characteristic or attitude that is believed to range across a continuum of values that cannot easily be directly measured. A color analog scale uses a gradual transition from green to yellow to red to represent a continuous pain spectrum rather than a specific number or description.

Another method, the Brief Pain Inventory (BPI), is a short form developed to measure pain intensity and the extent to which pain interferes with life activities. The BPI asks respondents to rate their current pain intensity, pain experienced in the last 24 hours and the degree to which pain interferes with seven domains of functioning: general activity, mood, walking ability, normal work (outside the home and housework), relations with other people, sleep and enjoyment of life (0 =does not interfere and 10 = interferes completely.)

The McGill Pain Questionnaire uses another approach. It consists primarily of three major classes of word descriptors – sensory, affective and evaluative – that are used by respondents to specify subjective pain experience. It also contains an intensity scale and other items to determine the properties of pain experience. This questionnaire is designed to provide quantitative measures of clinical pain that can be treated statistically.

Whatever type of scale is used, clinical interpretation is required. In situations in which a pain scale is used, a clinician trained in occupational medicine can provide useful insights at the onset of a work-related injury and through the recovery process.