Investigation of the Predictive Value of the Five-repetition Sit-to-stand Test (5R-STS) on the Outcome of Lumbar Back Surgery. The 5R-STS-III Study.

Sciatica is a disabling condition that affects many people. This condition has an enormous influence on the social functioning of patients. The clinical determination of the severity of back pain is mainly done with validated questionnaires, which express the subjective pattern of complaints in a score. These usually reflect the severity of the complaints, but there is still a lack of objective and quantitative tests.

Objective functional tests are tests in which the patient has to perform a prescribed procedure or movement while the duration of that movement is then registered. Such tests are already widely used in pneumology and cardiology, but not yet in spine surgery. So far, there are only a few objective tests for functional impairment in back pain such as the 6-minute walking test and timed-up-and-go test.

The validated five-repetition sit-to-stand test (5R-STS) is a standardized test that has its origin in pneumology and is derived from the 1-minute sit-to-stand test. In this test, the patient stands up and sits down for 1 minute as often as possible from a chair without armrests, counting the number of movements. This not only measures how mobile the patient is, but can also say something about the condition of the heart and lungs. Recently, the 5R-STS has been described, in which the time is measured in which the patient has to stand up straight and sit down again five times from a chair.

In spine disorders the 5R-STS had not yet been validated. In 2018, a research group formally validated this test for the first time in patients with lumbar hernia, lumbar canal stenosis, and degenerative spondylolisthesis.1 In this study (5R-STS-I)1 it was concluded that the 5R-STS provides additional information that the simple patient-reported outcome measures (PROMs, questionnaires) cannot demonstrate. It became clear that especially in patients with lumbar hernias two different patient groups existed, namely those with objective functional impairment (OFI) and those without OFI. This subdivision into two groups was even maintained after correction for pain levels. In a follow-up study (5R-STS-II)2 it was shown that when patients undergo the test without supervision - prior to surgery - the test results are equal.

In this study, the investigators want to assess whether there is a connection between the duration of the 5R-STS test and the outcome of low back operations after one year. In other words: What is the predictive value of this test on the result of surgery?