As surgeries become more available and advanced, a natural interest develops in measuring their outcomes. Although these studies are indicative of the success of the surgical sector, there does not exist enough assessments that measure the prevalence of postoperative disabilities according to Shulman et al. . Both survival and survival without disability should be studied to truly gauge how beneficial an operation is to a patient’s quality of life.
A disability is generally defined as a physical or mental impairment caused by a health condition, which may impact an individual’s ability to work, take care of themselves, and interact with society . To measure postoperative disability rates, it is important to include both assessments of physical function and quality of life . Not only should a postoperative patient’s symptoms be recorded, but also the impact of their symptoms on their general well-being, social-involvement, ability to fill life role activities, and cognitive well-being .
As disability rates are much more nuanced than morbidity and mortality rates, there are many factors that must be considered in the process. One of which is pain assessment. After an operation, patient pain is often recorded to assess the progression of the recovery process . Patients are usually asked to quantify their pain using the Numerical Rating Scale, but this method may have its own difficulties when dealing with patients who are not lucid . Additionally, pain measurement may easily be skewed by the patient’s personal pain experiences and cultural background . Challenges aside, taking an accurate assessment of the patient’s pain level is a crucial step in avoiding postoperative disabilities in the long run.
Another indicator of disability is frailty during recovery. Frailty is a state of increased vulnerability that correlates with but does not always equal disability . In a study on lung transplant patients, the postoperative patients were assessed for frailty using the Fried Frailty Phenotype and the Short Physical Performance Battery tests, which indicated that frail patients have higher tumor necrosis factor I and lower growth factor I, among other differences, which all are associated with greater disability rate and increased risk of death .
Naturally, frailty and pain are not enough to classify a postoperative patient as disabled. To further measure and diagnose disability rates, the World Health Organization has designed a test, the World Health Organization Disability Assessment Schedule 2.0 (WHODAS), that measures softer factors such as cognition, mobility, self-care, interpersonal relationships, work and household roles, and participation in society . This test can be administered in 5 minutes via telephone and consists of a survey of 12 items, each of which earns a score of 0-4 depending on the patient’s experiences . The total sum is then divided by 48 (the maximum score), and converted into a percentage, which can be analyzed with a larger pool of data . The WHO has deemed patients who receive a score of 25% or above disabled, and the patients whose scores increase by 8% or greater compared to their preoperative assessment have gained a new disability . WHODAS is given following surgery, then follow up assessments are conducted 30 days, 3, 6, and 12 months after the patient is discharged .
When compared to other postoperative assessments, such as the frailty assessment, WHODAS is shown to be reliable and high-quality . WHODAS is able to discriminate between good and poor qualities of recovery and has demonstrated that different types of surgery are associated with different disability rates — with the lowest rates of disability-free survival in orthopedic and neurosurgery patients and highest rates of new disability in thoracic surgery patients .
Although still in development, WHODAS is a very holistic approach to assessing postoperative disability and is certainly useful in surgical settings. As surgeries become more powerful and are able to cure and relieve greater symptoms of a disease state, it becomes even more urgent to measure survival and freedom from disability . Thus, for all in the health industry, developing a powerful postoperative disability assessment should be a primary aim, as it will directly link to the end goal of disability-free survival in all postoperative patients.
 Mark A. Shulman, et. al. “Measurement of Disability-free Survival after Surgery.” Anesthesiology, vol. 122, no. 3, 2015, p. 524-536., doi:10.1097/ALN.0000000000000586.
 Thee, Carsten, Ilies, et. al. “Reliability of the surgical Pleth index for assessment of postoperative pain.” European Journal of Anaesthesiology (EJA), vol. 32, no. 1, 2015, p. 44-48., doi:10.1097/EJA.0000000000000095
 Singer, Jonathan P., et. al. “Frailty Phenotypes, Disability, and Outcomes in Adult Candidates for Lung Transplantation.” American Journal of Respiratory and Critical Care Medicine, vol. 192, no. 11, 2015, p. 1325-34., doi:10.1164/rccm.201506-1150OC