The Six-Minute Walking Test (6MWT) as a Measure of Functional Impairment in Lumbar Degenerate Disc Disease.

Study Overview
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Brief Summary
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The study determines the reliability and validity of the 6-Minute Walking Test (6MWT) in patients with lumbar degenerative disc disease (DDD).

Detailed Description
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The purposes of the study is to assess the ability of the 6-Minute Walking Test (6MWT) as a reliable and standardized objective outcome assessment and its relation to already established subjective patient reported outcome measures in patients suffering from lumbar degenerative disc disease. We want to use an existing smartphone-application that uses global positioning system (GPS) coordinates to measure walking distance. Applying self- measurement of the 6MWT before and after a therapeutic intervention, we determine objective functional impairment (OFI) in patients. The results of this study add to the understanding of achievable objective outcomes after therapeutic interventions applied to patients with DDD and examines patients acceptance for smartphone based self-measurement. Primary Objectives The primary objective is to determine the reliability and validity of the 6-Minute Walking Test (6MWT) in patients with lumbar degenerative disc disease (DDD) Secondary objectives are to correlate objective functional impairment (OFI) with already established patient-rated outcome measures (PROMs) in the sense of cross-validation. To correlate OFI, as determined by the 6MWT with OFI that is determined by another objective test, the TUG test to then analyze the change in OFI in patients before and after surgical intervention to determine whether patients prefer the objective (6MWT) or subjective (PROMs) repeated assessment of their functional condition.

Official Title
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The Six-Minute Walking Test (6MWT) as a Measure of Functional Impairment in Lumbar Degenerate Disc Disease.

Conditions
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Lumbar Disc Disease, Lumbar Spine Degeneration, Lumbar Spinal Stenosis

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient scheduled for spine surgery with one of the following diagnosis (1) lumbar disc herniation (LDH), (2) lumbar spinal stenosis lumbar (LSS) or lumbar DDD with or without instability requiring lumbar fusion (transforaminal lumbar interbody fusion, posterior lumbar interbody fusion, or extreme lateral interbody fusion) Male and Female subjects ≥ 18 years Written informed consent Exclusion Criteria: Pregnancy Inability to walk (extreme pain or severe neurological deficits) Severe Chronic Obstructive Lung Disease (COPD) corresponding to ≥ Gold III Severe heart failure corresponding to ≥ New York Heart Association (NYHA) III Lung cancer and diffuse parenchymal lung disease Other medical reasons interfering with the patient's ability to walk and perform the 6MWT (e.g., osteoarthritis disease of the lower extremities, Parkinson's disease, heart failure, hip or knee prosthesis etc.) Unavailability for follow up and/or inability to complete assessment (planning to move, no smartphone, etc.).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| DDD Patients<br>All patients presenting to the neurosurgical department of the Kantonsspital St. Gallen (KSSG) with a diagnosed DDD fulfilling the inclusion criteria and scheduled for surgery will be considered for this study. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Raw walking distance | Raw walking distance (in m), as measured with the 6MWT, between the baseline- (before surgery) and follow-up assessment | 4-12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| TTFS | Difference in Time to First Symptoms (TTFS; in sec) as measured by the 6MWT, between the baseline- and follow-up assessment | 4-12 weeks | 
| DTFS | Difference in Distance to First Symptoms (DTFS, in m), as measured by the 6MWT, between the baseline- and follow-up assessment | 4-12 weeks | 
| Zurich Claudication Questionnaire (ZCQ) | Difference in PROM, as measured by the Zurich Claudication Questionnaire (ZCQ average score, range 0 (best) - 4,5 (worst), between the baseline- and follow-up assessment. | 4-12 weeks | 
| Core Outcome Measures Index (COMI) | Difference in health-related quality of life (hrQoL), as measured by the Core Outcome Measures Index (COMI average score, range 0 (best) - 10 (worst)), between the baseline- and follow-up assessment | 4-12 weeks | 
| TTFS/ZCQ baseline | Correlation of TTFS/DTFS in the 6MWT with the ZCQ score at baseline | 4-12 weeks | 
| TTFS/ZCQ follow-up | Correlation of TTFS in the 6MWT with the ZCQ score at follow-up | 4-12 weeks | 
| TTFS/COMI baseline | Correlation of TTFS/DTFS in the 6MWT with the COMI score at baseline | 4-12 weeks | 
| TTFS/COMI follow-up | Correlation of TTFS/DTFS in the 6MWT with the COMI score at follow-up | 4-12 weeks | 
| TTFS/TUG baseline | Correlation of TTFS/DTFS in the 6MWT with the Timed up go Test (TUG) at baseline | 4-12 weeks | 
| TTFS/TUG follow-up | Correlation of TTFS/DTFS in the 6MWT with the TUG at follow-up | 4-12 weeks | 
| Test-retest reliability of the 6MWT | Test-retest reliability of the 6MWT in patients with lumbar degenerate disc disease, tested two consecutive times with the 6MWT App (within 3 days) before as well as after surgery. | 6 weeks to 1 day before surgery as well as 4-12 weeks after surgery |