US Pharm. 2023;48(3):4.

Often debilitating, chronic pain is one of the most common reasons individuals seek medical help. About 65 million adults in the United States are affected by chronic pain. Between 67% and 88% of them also suffer from sleep disturbances, including longer and more frequent nocturnal awakenings and poorer sleep quality. Moreover, sleep disorders also may exacerbate pain by contributing to the development of obesity, diabetes mellitus, and depression.

Because chronic pain and sleep are thought to be correlated, treatment of one could be beneficial to the other. One such treatment is spinal cord stimulation, which shows mounting evidence that it improves aspects of sleep and has demonstrated efficacy in treating a multitude of chronic pain conditions. This treatment involves an implantable spinal cord stimulator that sends low levels of electricity directly into the spinal cord to relieve pain. However, its impact on patients’ lives has yet to be determined.

Researchers from Florida Atlantic University Schmidt College of Medicine, in collaboration with Albany Medical Center, conducted a study to better understand the effect of spinal cord stimulation on chronic pain and sleep.

For the study, participants completed a battery of certified outcome measures regarding sleep, pain, functional status, and overall quality of life at various time periods throughout the study. These surveys were given preoperatively and either 6 months or 1 year postoperatively. Participants also were asked about their satisfaction with the spinal cord stimulation procedure and if they would have the surgery again.

Researchers examined the relationship between pain outcome measures using the Insomnia Severity Index, a clinical screening tool that assesses the severity of both nighttime and daytime components of insomnia. With this tool, they established the minimally clinical important difference—the smallest noticeable change that a patient perceives as clinically significant and which could indicate a change in management. Minimally clinical important difference is particularly useful in evaluating newer treatments, as these have a smaller cohort with which to compare for statistical significance.

The study, published in Stereotactic and Functional Neurosurgery, successfully established minimally clinical important difference ranges for the Insomnia Severity Index outcome measure to help gauge improvement in insomnia after spinal cord stimulation.

The results showed Insomnia Severity Index improvement of 30% or more in 39.1% of the participants and an Epworth Sleepiness Scale of 30% or more in 28.1% of the participants. Minimally clinical important difference values of 2.4 to 2.6 correlated with improvement in disability and depression in the participants. The study revealed associations with sleep and both pain and depression but no correlation between sleep and spinal cord stimulation success.

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