Subjective and Objective Measures of Symptoms, Function, and Outcome in Patients With Degenerative Spine Disease

Reliability of self-measured objective functional impairment using the timed up and go test in patients with diseases of the spine

BACKGROUND

Accurate assessment of a patient's functional status is crucial for determining the need for treatment and evaluating outcomes. Objective functional impairment (OFI) measures, alongside patient-reported outcome measures (PROMs), have been proposed for spine diseases. The Timed-Up and Go (TUG) test, typically administered by healthcare professionals, is a well-studied OFI measure. This study investigates whether patient self-measurement of TUG is similarly reliable.

METHODS

In a prospective, observational study, patients with spinal diseases underwent two TUG assessments: one measured by a healthcare professional and one self-measured by the patient. Interrater reliability was assessed using the intraclass correlation coefficient (ICC) with a two-way random-effects model, considered excellent between 0.75 - 1.00. Paired t-tests directly compared both measurements. The impact of variables such as age, sex, disease type, symptom severity (via PROMs), comorbidities, and frailty on reliability was also analysed.

RESULTS

Seventy-four patients were included, with a mean age of 62.9 years (SD 17.8); 29 (39.2%) were female. The majority (64.9%) were treated for degenerative disc disease. The lumbo-sacral region was most affected (71.6%), and 47.3% had previous surgeries. Patient self-measurement reliability was excellent (ICC 0.8740, p < 0.001), and the difference between healthcare professional (19.3 ± 9.4 s) and patient measurements (18.4 ± 9.7 s) was insignificant (p = 0.116). Interrater reliability remained high in patients > 65 years (ICC 0.8584, p < 0.001), patients with ASA grades 3&4 (ICC 0.7066, p < 0.001), patients considered frail (ICC 0.8799, p < 0.001), and in patients not using any walking aid (ICC 0.8012, p < 0.001). High symptom severity still showed strong reliability (ICC 0.8279, p < 0.001 for Oswestry Disability Index > 40; ICC 0.8607, p = 0.011 for Neck Disability Index > 40).

CONCLUSIONS

Patients with spine diseases can reliably self-measure OFI using the TUG test. The interrater reliability between self-measurements and those by healthcare professionals was excellent across all conditions. These findings could optimize patient assessments, especially in resource-limited settings.

Transforaminal lumbar interbody fusion with or without release of the anterior longitudinal ligament: A single-center, retrospective observational cohort study

Background

Transforaminal anterior release (TFAR) is a technical extension of the transforaminal lumbar interbody fusion (TLIF) procedure with deliberate release of the anterior longitudinal ligament (ALL).

Methods

In a retrospective, single-center observational cohort study, consecutive adult patients undergoing TLIF surgery at L4/L5 and/or L5/S1 between 01/2018 and 12/2022 for degenerative disc disease or deformity were considered. The TFAR group (with ALL release) was compared to a standard TLIF group (without ALL release), matched in a 1:3 ratio. Uni- and multivariable logistic regression models were built to estimate the likelihood of any adverse event (AE), reoperation, and excellent/good clinical outcome at 12 months.

Results

Of 438 patients, 18 undergoing TFAR were matched to 53 undergoing standard TLIF. TFAR procedures were frequently part of extensive, anterior-posterior or multilevel fusion procedures with longer surgery time and higher blood loss. The rates of intraoperative surgical AEs were similar (16.7 vs. 11.3%, p=.789). The rates and severities of surgical AEs, as well as reoperation rates and clinical outcomes were similar at time of discharge, 90 days, and 12 months postoperatively (all p>.05). TFAR allowed for an increase in total lumbar lordosis of 16.1° and in lumbar lordosis between L4 and S1 of 16.3° at discharge, which was maintained during follow-up. In both the uni- and multivariable models, patients undergoing TFAR were as likely as patients undergoing standard TLIF to experience any AE (adjusted OR 0.78, 95% CI 0.21-2.94), any reoperation (aOR 0.46, 95% CI 0.11-1.90) or excellent/good clinical outcome at 12 months (aOR 2.01, 95% CI 0.52-7.74).

Conclusions

The TFAR technique has a safety profile which is comparable to the standard TLIF procedure, but it allows for a greater restoration of lumbar lordosis at L4-S1. We suggest considering the TFAR technique in selected patients with sagittal imbalance and mobile segments for restoration of lumbar lordosis.

Standardizing Continuous Physical Activity Monitoring in Patients with Cervical Spondylosis

STUDY DESIGN/SETTING

Prospective cohort study.

OBJECTIVE

To use a commercial wearable device to measure real-life, continuous physical activity in patients with CS and to establish age-adjusted and sex-adjusted standardized scores.

SUMMARY OF BACKGROUND DATA

Patients with cervical spondylosis (CS) often present with pain or neurologic deficits that result in functional limitations and inactivity. However, little is known regarding the influence of CS on the patient's real-life physical activity.

METHODS

This study included 100 English-speaking adult patients with cervical degenerative diseases undergoing elective spine surgery at Stanford University who owned iPhones. Patients undergoing surgery for spine infections, trauma, tumors, or lumbar degenerative disease were excluded. Activity two weeks before surgery was expressed as raw daily step counts. Standardized z-scores were calculated based on age-specific and sex-specific values of a control population. Responses to patient-reported outcome measures (PROMs) surveys assessed convergent validity. Functional impairment was categorized based on predetermined z-score cut-off values.

RESULTS

Thirty CS with a mean (±SD) age of 56.0 (±13.4) y wore an Apple Watch for ≥8 hours/day in 87.1% of the days. The mean watch wear time was 15.7 (±4.2) hours/day, and the mean daily step count was 6400 (±3792). There was no significant difference in activity between 13 patients (43%) with myelopathy and 17 (57%) without myelopathy. Test-retest reliability between wearable step count measurements was excellent (ICC β=0.95). Physical activity showed a moderate positive correlation with 36-Item Short Form Survey Physical Component Summary, EuroQol-5-dimension visual analog scale, and Patient-Reported Outcomes Measurement Information System Physical Function Subscale. Activity performance was classified into categories of "no impairment" [step count=9640 (±2,412)], "mild impairment" [6054(±816)], "moderate impairment" [3,481 (±752)], and "severe impairment" [1,619 (±240)].

CONCLUSION

CS patients' physical activity is significantly lower than the general population or the frequently stated goals of 7000 to 10,000 steps/day. Standardized, continuous wearable physical activity monitoring in CS is a reliable, valid, and normalized outcome tool that may help characterize functional impairment before and after spinal interventions.

Minimally-invasive lateral thoracic and lumbar interbody fusion (LLIF) with expandable interbody cages - Considerations, complications & outcomes

Introduction

Reports about lateral lumbar or thoracic interbody fusion (LLIF) using expandable interbody spacers are sparse.

Research question

To report our experience with the use of expandable spacers for LLIF.

Material and methods

We reviewed all consecutive LLIF patients with use of an expandable titanium interbody implant (ELSA® Expandable Integrated LLIF Spacer, Globus Medical Inc, PA (USA)) between September 2018 and January 2024.

Results

We identified 503 patients, in which we performed LLIF at 732 levels. In 63 patients (12.5%) and 70 levels (9.6%) an expandable spacer was used. The mean age was 61.4 years, 57.1% were females. LLIF was performed between T11/12 - L4/5 in the setting of fusion procedures (mono-/bisegmental (20; 28.6%), 3-7 segments (29; 41.4%); >7 segments (21; 30.0%)), of which 21 (33.3%), 20 (31.8%) and 22 (34.9%) were for traumatic, deformity/revision and other diagnoses. Surgery included release of the anterior longitudinal ligament in 30 cases (42.9%). Intraoperative adverse events (AEs) were noted in 2 (3.2%), postoperative AEs in 27 (42.9%) at discharge, 17 (27.0%) at 3 months and 14 (22.2%) at 12 months. Segmental sagittal Cobb angle changed from 1.3° (preoperative) to 13.0° at discharge (p < 0.001), 12.7° at 3 months (p < 0.001) and 13.3° at 12 months (p < 0.001). Functional outcome was excellent/good in 43 (68.3%; 5 missing) at 3 months and in 37 (58.7%; 10 missing) at 12 months.

Discussion and conclusion

The use of LLIF with an expandable spacer was safe, promoted solid fusion and enabled powerful correction of sagittal segmental Cobb angle, which was maintained during follow-up.

Standardizing Physical Activity Monitoring in Patients With Degenerative Lumbar Disorders

BACKGROUND AND OBJECTIVES

Degenerative thoracolumbar disorders (DTDs) typically cause pain and functional impairment. However, little is known regarding the DTD impact on patient's real-life physical activity. The objective of this study is to validate a wearable measure of physical activity monitoring in patients with DTD and to create gender- and sex-specific performance thresholds that are standardized to the mean of a control population.

METHODS

A commercially available smartwatch (Apple Watch) was used to monitor preoperative physical activity in patients undergoing surgery for DTD. Mean preoperative physical activity 2 weeks before the scheduled surgery was expressed as raw step count. Standardized z-scores were referenced to age- and sex-specific values of a control population from a large public database. Step counts were assessed for convergent validity with established patient-reported outcome measures, and impairment in activity was stratified into performance groups based on z-score cutoff values.

RESULTS

Sixty-five patients (62% female) with a mean (±SD) age of 63.8 (±12.8) years had a mean preoperative daily step count of 5556 (±3978). Physical activity showed significant correlation with patient-reported outcome measures, including Oswestry disability index (r = -0.26, 95% CI: -0.47-0.01), 36-Item Short Form Survey Physical Component Summary score (r = 0.30, 95% CI: 0.06-0.51), and Patient-Reported Outcomes Measurement Information System Physical Function (r = 0.49, 95% CI: 0.27-0.65). "No," "Mild," "moderate," and "severe impairment" in activity performance were defined as corresponding z-scores of >0, 0 to -0.99, -1 to -1.99, and ≤-2, accounting for 22%, 34%, 40%, and 5% of the study population. Each one-step category increase in activity impairment resulted in increased subjective disability as measured by the Oswestry Disability Index, 36-Item Short Form Survey Physical Component Summary, and Patient-Reported Outcomes Measurement Information System Physical Function (all P -values <.05).

CONCLUSION

We establish the first wearable objective measure of real-life physical activity for patients with DTD, with the first age- and sex-adjusted standard scores to enable clinicians and researchers to set treatment goals and directly compare activity levels between individual patients with DTD and normal controls.

Outcome Reporting in Spine Surgery: A Review of Historical and Emerging Trends

The general objectives of spine surgery are to alleviate pain, restore neurologic function, and prevent or treat spinal deformities or instability. The accumulating expanse of outcome measures has allowed us to more objectively quantify these variables and, therefore, gauge the success of treatments, ultimately improving the quality of the delivered health care. It has become increasingly evident that spinal conditions and their accompanying interventions affect all aspects of a patient's life, including their physical, mental, emotional, and social well-being. This underscores the challenge of creating clinically relevant and accurate outcome measures in spine care, and the reason why there is a growing recognition of the importance of subjective measures such as patient-reported outcome measures, that consider a patients' health-related quality of life. Subjective measures provide valuable insights into patient experiences and perceptions of treatment outcomes, whereas objective measures provide a reproducible glimpse into key radiographic and clinical parameters that are associated with a successful outcome. In this narrative review, we provide a detailed analysis of the most common subjective and objective outcome measures employed in spine surgery, with a special focus on their current role as well as the possible future of outcome reporting.

Spine patient care with wearable medical technology: state-of-the-art, opportunities, and challenges: a systematic review

BACKGROUND CONTEXT

Healthcare reforms that demand quantitative outcomes and technical innovations have emphasized the use of Disability and Functional Outcome Measurements (DFOMs) to spinal conditions and interventions. Virtual healthcare has become increasingly important following the COVID-19 pandemic and wearable medical devices have proven to be a useful adjunct. Thus, given the advancement of wearable technology, broad adoption of commercial devices (ie, smartwatches, phone applications, and wearable monitors) by the general public, and the growing demand from consumers to take control of their health, the medical industry is now primed to formally incorporate evidence-based wearable device-mediated telehealth into standards of care.

PURPOSE

To (1) identify all wearable devices in the peer-reviewed literature that were used to assess DFOMs in Spine, (2) analyze clinical studies implementing such devices in spine care, and (3) provide clinical commentary on how such devices might be integrated into standards of care.

STUDY DESIGN/SETTING

A systematic review.

METHODS

A comprehensive systematic review was conducted in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA) across the following databases: PubMed; MEDLINE; EMBASE (Elsevier); and Scopus. Articles related to wearables systems in spine healthcare were selected. Extracted data was collected as per a predetermined checklist including wearable device type, study design, and clinical indices studied.

RESULTS

Of the 2,646 publications that were initially screened, 55 were extensively analyzed and selected for retrieval. Ultimately 39 publications were identified as being suitable for inclusion based on the relevance of their content to the core objectives of this systematic review. The most relevant studies were included, with a focus on wearables technologies that can be used in patients' home environments.

CONCLUSIONS

Wearable technologies mentioned in this paper have the potential to revolutionize spine healthcare through their ability to collect data continuously and in any environment. In this paper, the vast majority of wearable spine devices rely exclusively on accelerometers. Thus, these metrics provide information about general health rather than specific impairments caused by spinal conditions. As wearable technology becomes more prevalent in orthopedics, healthcare costs may be reduced and patient outcomes will improve. A combination of DFOMs gathered using a wearable device in conjunction with patient-reported outcomes and radiographic measurements will provide a comprehensive evaluation of a spine patient's health and assist the physician with patient-specific treatment decision-making. Establishing these ubiquitous diagnostic capabilities will allow improvement in patient monitoring and help us learn about postoperative recovery and the impact of our interventions.

The test-retest reliability and minimal clinically important difference of the Dubousset Functional Test and its correlation with Rolland Morris disability questionnaire in chronic non-specific low back pain

OBJECTIVE

This study examines the test-retest reliability, the minimal clinically important difference (MCID), and its correlation with the Rolland Morris Disability Questionnaire (RMDQ) of the Dubousset Functional Test (DFT) in evaluating the functional capacity and dynamic balance of patients with chronic non-specific low back pain (cnsLBP).

METHODS

Seventy-five patients with cnsLBP aged 18 years and over were included. The Five-Repetition Sit-To-Stand Test (5R-STS), the subcomponents of the DFT (the Up and Walk Test, the Steps Test, the Down and Sitting Test, and the Dual-Tasking Test) were administered to the patients. Patients were rested for 1 h, and the DFT was applied again. Pain level was evaluated with the Visual Analogue Scale before the tests started and after the tests were completed. Self-report function assessment was made using the RMDQ.

RESULTS

The test-retest reliability of the subcomponents of the DFT was excellent. The ICCs were: 0.91, 0.86, 0.89, and 0.89, respectively. The standard measurement errors of the subcomponents of the DFT were 0.32, 0.12, 0.14, and 0.25, respectively. The subcomponents of the DFT were highly correlated with the RMDQ and 5R-STS with the correlation coefficients of 0,83, 0,83, 0,79, 0,83 and 0,81, 0,75, 0,73, and 0,82, respectively (p < 0.01). The MCIDs of the subcomponents were 0,60, 0,23, 0,27, and 0,48, respectively.

CONCLUSION

The DFT is reliable in evaluating patients' functional capacity and dynamic balance with cnsLBP without causing discomfort. It is simple, quick, and simultaneously assesses multiple areas contributing to spinal alignment, muscle integrity, and balance.

Distance to first symptoms measured by the 6-min walking test differentiates between treatment success and failure in patients with degenerative lumbar disorders

PURPOSE

The smartphone-based 6-min walking test (6WT) is an established digital outcome measure in patients undergoing surgery for degenerative lumbar disorders (DLD). In addition to the 6WTs primary outcome measure, the 6-min walking distance (6WD), the patient's distance to first symptoms (DTFS) and time to first symptoms (TTFS) can be recorded. This is the first study to analyse the psychometric properties of the DTFS and TTFS.

METHODS

Forty-nine consecutive patients (55 ± 15.8 years) completed the 6WT pre- and 6 weeks (W6) postoperative. DTFS and TTFS were assessed for reliability and content validity using disease-specific patient-reported outcome measures. The Zurich Claudication Questionnaire patient satisfaction subscale was used as external criterion for treatment success. Internal and external responsiveness for both measures at W6 was evaluated.

RESULTS

There was a significant improvement in DTFS and TTFS from baseline to W6 (p < 0.001). Both measures demonstrated a good test-retest reliability (β = 0.86, 95% CI 0.81-0.90 and β = 0.83, 95% CI 0.76-0.87, both p < 0.001). The DTFS exceeded the 6WD capability to differentiate between satisfied (82%) and unsatisfied patients (18%) with an AUC of 0.75 (95% CI 0.53-0.98) vs. 0.70 (95% CI 0.52-0.90). The TTFS did not demonstrate meaningful discriminative abilities.

CONCLUSION

Change in DTFS can differentiate between satisfied and unsatisfied patients after spine surgery. Digital outcome measures on the 6WT metric provide spine surgeons and researchers with a mean to assess their patient's functional disability and response to surgical treatment in DLD.

External Validation of the Minimum Clinically Important Difference in the Timed-up-and-go Test After Surgery for Lumbar Degenerative Disc Disease

STUDY DESIGN

Prospective observational cohort study.

OBJECTIVE

The aim of this study was to provide external validation of the minimum clinically important difference (MCID) of the Timed-up-and-go (TUG) test.

SUMMARY OF BACKGROUND DATA

The TUG test is one of the best explored and most frequently applied objective task-based functional outcome measure in patients with lumbar degenerative disc disease (DDD). The increased use of the TUG test is based on its solid psychometric properties; however, an external validation of the originally determined MCID is lacking.

METHODS

Forty-nine patients with lumbar DDD, scheduled for elective spine surgery, were assessed pre- and 6-weeks (W6) postoperative. MCID values were calculate for raw TUG test times (seconds) and standardized TUG z scores using three different computation methods and the following established patient-reported outcome measures (PROMs) as anchors: Visual Analog Scales (VAS), Core Outcome Measures Index Back, Zurich Claudication Questionnaire (ZCQ).

RESULTS

The three computation methods generated a range of MCID values, depending on the PROM used as anchor, from 0.9 s (z score of 0.3) based on the VAS leg pain to 3.0 seconds (z score of 2.7) based on the ZCQ physical function scale. The average MCID of the TUG test across all anchors and computation methods was 2.1 s (z score of 1.5). According to the average MCID of raw TUG test values or TUG z scores, 41% and 43% of patients classified as W6 responders to surgery, respectively.

CONCLUSION

This study confirms the ordinally reported TUG MCID values in patients undergoing surgery for lumbar. A TUG test time change of 2.1 seconds (or TUG z score change of 1.5) indicates an objective and clinically meaningful change in functional status. This report facilitates the interpretation of TUG test results in clinical routine as well as in research.Level of Evidence: 3.

Smartphone-based real-life activity data for physical performance outcome in comparison to conventional subjective and objective outcome measures after degenerative lumbar spine surgery

Introduction

Outcome assessments after surgery for degenerative lumbar disorders (DLDs) rely on subjective patient-reported outcomes (PROMs). New objective functional capacity tests, like the smartphone-based 6-min walking test (6WT), have been introduced but presumably also do not reflect the patient's real-life functional performance.

Research question

Pilot study to analyze changes in smartphone-based real-life activity data for physical performance outcome in patients undergoing surgery for DLD.

Material and methods

Prospective observational study of DLD patients. Objective functional capacity and subjective outcomes were measured using 6WT and PROMs. Real-life physical performance data were acquired retrospectively using Apple iPhone Health data and compared against objective capacity and subjective outcomes.

Results

Eight patients (mean 46 years, 62% male) provided 286.858 smartphone mile counts. PROMs and physical capacity (6WT) significantly improved postoperatively. 6WT results increased from 352m pre-to 555/567m at 6/12 weeks postoperatively (p ​= ​0.03). For physical performance a linear mixed effect models showed an increase in daily distance in the first 4 months after surgery (slope +0.178; p ​< ​0.001). However, those increases reversed from 4 until 12 months postoperatively (negative slope estimate of −0.076; p ​< ​0.001). Smartphone-derived physical performance measures showed a positive correlation with corresponding physical capacity in the 6WT (R ​= ​0.57,p ​= ​0.004) and negative correlations with PROMs (COMI: R ​= ​−0.62p ​= ​0.001; ZCQ-Physical-Function: R ​= ​−0.68,p ​< ​0.001; ZCQ-Symptom-Severity: R ​= ​−0.52,p ​= ​0.009).

Discussion and conclusion

Smartphone-based real-life activity data allows for longitudinal physical performance assessment. Physical performance correlated with physical capacity and patient's subjective perception of disability. However, physical performance may be more resistant to postoperative longtime change which should consult a more cautious use as objective outcome measure.

•

Smartphone-based activity data allows for continuous longitudinal physical performance assessment after lumbar spine surgery.

•

It captures both, a preoperative deterioration, and a postoperative improvement of patients' physical performance.

•

Although smartphone-based performance correlated with physical capacity/PROMs, daily activity decreased again postoperatively

•

This discrepancy indicates that smartphone-based performance may provide a more in-depth assessment of function over time.

Circumferential fusion with open versus percutaneous posterior fusion for lumbar isthmic spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate the clinical and radiographic differences between patients who underwent anterior lumber interbody fusion (ALIF) with either open or percutaneous posterior fusion for lumbar isthmic spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Circumferential fusion for isthmic spondylolisthesis is commonly performed with superior clinical outcomes, fusion rates, and restoration of sagittal balance when compared to posterior fusion alone. The outcomes comparing traditional open versus percutaneous posterior fusion in this setting have not been fully evaluated.

METHODS

A retrospective review of patients who underwent ALIF with either traditional open or percutaneous posterior fusion for isthmic spondylolisthesis between 2014 and 2019 was conducted. Patient demographics, surgical characteristics, and radiographic and clinical outcomes were compared between groups.

RESULTS

A total of 79 patients were included in the final analysis, with 49 in the Open group and 30 in the Percutaneous group. No differences were found with regard to demographic factors between groups including sex, body mass index (BMI), diabetic status, and smoking status. The percutaneous group had less estimated blood loss (EBL, 69.2 mL) and shorter length of stay (3.06 days) compared to the open group (446 mL, p = 0.017; 3.98 days, p = 0.003). Both groups demonstrated significant improvement in all clinical outcome measures after surgery (PCS-12, MCS-12, ODI, VAS Back, and VAS Leg scores). The percutaneous group achieved greater ∆VAS Back (Open = 3.55, Perc = 5.17; p = 0.045) and also had a significantly greater improvements in recovery ratio for VAS Back (Open: 0.43, Perc: 0.73; p = 0.037) and ODI (Open: 0.40, Perc = 0.67; p = 0.031). Regression analysis demonstrated percutaneous surgery to be significant predictor of superior improvement in VAS Back scores (β = 1.957, p = 0.027).

CONCLUSION

ALIF with percutaneous posterior fusion affords greater improvement in back pain and disability when compared to ALIF with open posterior fusion for isthmic spondylolisthesis.

LEVEL OF EVIDENCE

III.

Assessment of the Minimum Clinically Important Difference in the Smartphone-based 6-minute Walking Test After Surgery for Lumbar Degenerative Disc Disease

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

The aim of this study was to determine the minimum clinically important difference (MCID) of the 6-minute walking test (6WT) after surgery for lumbar degenerative disc disease (DDD).

SUMMARY OF BACKGROUND DATA

The smartphone-based 6WT is a valid and reliable tool to quantify objective functional impairment in patients with lumbar DDD. To date, the MCID of the 6WT has not been described in patients with DDD.

METHODS

We assessed patients pre- and 6-weeks postoperatively, analyzing both raw 6-minute walking distances (6WD; in meters) and standardized 6WT z scores. Three methods were applied to compute MCID values using established patient-reported outcomes measures (PROMs) as anchors (VAS back/leg pain, Zurich Claudication Questionnaire [ZCQ], Core Outcome Measures Index [COMI]): average change, minimum detectable change, and the change difference approach.

RESULT

We studied 49 patients (59% male) with a mean age of 55.5 ± 15.8 years. The computation methods revealed MCID values ranging from 81 m (z score of 0.9) based on the VAS back pain to 99 m (z score of 1.0) based on the ZCQ physical function scale. The average MCID of the 6WT was 92 m (z score of 1.0). Based on the average MCID of raw 6WD values or standardized z scores, 53% or 49% of patients classified as 6-week responders to surgery for lumbar DDD, respectively.

CONCLUSION

The MCID for the 6WT in lumbar DDD patients is variable, depending on the calculation technique. We propose a MCID of 92m (z score of 1.0), based on the average of all three methods. Using a z score as MCID allows for the standardization of clinically meaningful change and attenuates age- and sex-related differences.Level of Evidence: 3.