Understanding the minimum clinically important difference: a review of concepts and methods

How do idiopathic scoliosis patients who improve after surgery differ from those who do not exceed a minimum detectable change?

INTRODUCTION

The minimum detectable change (MDC) of the SRS-22 subtotal score is 6.8 points. With the use of this value, patients who have undergone surgery for idiopathic scoliosis can be dichotomized into two groups: the successful (S) group (those who have reached or exceeded this limit) and the unsuccessful (Un-S) group (those in whom the change was smaller). The aim of this study was to analyze the clinical and radiological differences between these patient groups, as well as those related to the surgical technique.

MATERIAL AND METHODS

The study included 91 patients (77 women and 14 men, mean age 18.1 years). All patients completed the SRS-22 questionnaire preoperatively and at follow-up (mean 45.6 months). In addition, radiological and surgical data were collected: levels instrumented, number of fused vertebrae, and use of thoracoplasty.

RESULTS

Based on the MDC of the SRS-22 subtotal score, patients were assigned to the Un-S group (44 cases, 48.4%) or S group (47 cases). Groups were similar in age, sex, number of fused vertebrae, percentage of patients who underwent thoracoplasty, and the upper and lower instrumented levels. The magnitude of the major curve and percentage of correction after surgery were also similar (Un-S group 62.3º, 53.2%; S group 64.3º, 49.9%). As compared to Un-S group, S patients had a poorer preop score in all the SRS-22 domains, and a clinically significant postop improvement in pain, perceived body image, mental health, and subtotal score. In contrast, the Un-S group showed a worsening of pain, function, mental health, and subtotal score, and a clinically nonsignificant improvement in perceived body image on the follow-up questionnaire. There were no significant differences in the satisfaction domain score between groups (4.36 vs. 4.62). On ROC curve analysis, a preop subtotal score of 74 points predicted allocation to the S or Un-S group at follow-up with 79% sensitivity and 76% specificity.

CONCLUSION

The preop subtotal score of the SRS-22 is a good predictor of the clinical response to surgery.

Validity, responsiveness, and clinically important difference of the ABILHAND questionnaire in patients with stroke

OBJECTIVE

To investigate the criterion-related validity, responsiveness, and clinically important differences of the ABILHAND questionnaire in patients with stroke.

DESIGN

Validation and clinimetric study.

SETTING

Three medical centers.

PARTICIPANTS

Patients with stroke (N=51).

INTERVENTIONS

A total of 51 patients with stroke received 1 of 3 upper extremity rehabilitation programs for 4 weeks.

MAIN OUTCOME MEASURES

The ABILHAND and the criterion measures, including the Stroke Impact Scale (SIS), FIM, Nottingham Extended Activities of Daily Living (NEADL), and accelerometers, were administered at pretreatment and posttreatment. The score of the ABILHAND, given in logits, was based on the conversion of the ordinal score into a linear measure of ability.

RESULTS

Correlation coefficients (Pearson r) were moderate to large between the ABILHAND and SIS physical domains (.54-.66), fair to moderate between the ABILHAND and FIM-motor and NEADL (.28-.48), and moderate between the ABILHAND and accelerometer data (.45-.54). The responsiveness of the ABILHAND was large (standardized response mean=1.27). The minimal clinically important difference range for the ABILHAND was .26 to .35, and 51.0% of the patients showed a positive change that exceeded the lower bound of a clinically important difference after intervention.

CONCLUSIONS

The results support that the ABILHAND is an appropriate outcome measure for assessing upper extremity performance in daily activities in patients with stroke and is sensitive to detect change after rehabilitative interventions. The change score of a patient with stroke on the ABILHAND should reach .26 to .35 logits points to be regarded as a clinically important change.

Measuring clinically important change with the Patient-rated Tennis Elbow Evaluation

Introduction

The Patient-rated Tennis Elbow Evaluation (PRTEE) enables quantitative rating by the patient of pain and functional impairment associated with tennis elbow or lateral elbow tendinopathy. When used as an outcome measure in trials of therapies, a minimum clinically important difference (MCID) value is required to interpret trial outcomes. This study aimed to calculate the MCID for a sample of patients diagnosed with lateral elbow tendinopathy (LET).

Methods

The PRTEE was used as an outcome measure with participants in a trial of a novel therapy for LET. It was administered at baseline and after treatment, three weeks later. Score changes were compared with patient-rated global change scores using receiver operating curve analysis. MCID values were calculated for two different criteria of clinically important difference and the effects of baseline symptom severity on the MCID were investigated.

Results

Data were available from 57 participants, with PRTEE scores in the range 13–81/100. For clinical significance defined as ‘a little better’ the MCID for the total PRTEE score was 7/100 or 22% of baseline score. For clinical significance defined as ‘much better’ or ‘completely recovered’, the MCID was 11/100 or 37% of baseline score. The MCID value was higher for a subgroup with greater baseline severity.

Conclusions

Substantial changes in the PRTEE scores are required before they can be considered clinically significant. Clinically significant change varies according to the baseline score. The instrument may be less sensitive to change when used by people who are symptomatic in their non-dominant arm.

Estimation of minimum clinically important difference for pain in fibromyalgia

OBJECTIVE

To estimate the minimum clinically important difference (MCID) for several pain measures obtained from the Brief Pain Inventory (BPI) for patients with fibromyalgia.

METHODS

Data were pooled across 12-week treatment periods from 4 randomized, double-blind, placebo-controlled studies designed to evaluate the safety and efficacy of duloxetine for the treatment of fibromyalgia. Each study enrolled subjects with American College of Rheumatology--defined fibromyalgia who presented with moderate to severe pain. The MCIDs for the BPI average pain item score and the BPI severity score (the mean of the BPI pain scale values: right now, average, least, and worst) were estimated by anchoring against the Patient's Global Impressions of Improvement scale.

RESULTS

The anchor-based MCIDs for the BPI average pain item and severity scores were 2.1 and 2.2 points, respectively. These MCIDs correspond to 32.3% and 34.2% reductions from baseline in scores.

CONCLUSION

In these analyses, the MCIDs for several pain measures obtained from the BPI were similar (∼2 points) and corresponded to a 30-35% improvement from baseline to end point. These findings may be beneficial for use in designing clinical trials in which the BPI is used to evaluate improvements in pain severity.

Statistical, practical, clinical, and personal significance: definitions and applications in speech-language pathology

PURPOSE

To discuss constructs and methods related to assessing the magnitude and the meaning of clinical outcomes, with a focus on applications in speech-language pathology.

METHOD

Professionals in medicine, allied health, psychology, education, and many other fields have long been concerned with issues referred to variously as practical significance, clinical significance, social validity, patient satisfaction, treatment effectiveness, or the meaningfulness or importance of beyond-clinic or real-world treatment outcomes. Existing literature addressing these issues from multiple disciplines was reviewed and synthesized.

CONCLUSIONS

Practical significance, an adjunct to statistical significance, refers to the magnitude of a change or a difference between groups. The appropriate existing term for the interpretation of treatment outcomes, or the attribution of meaning or value to treatment outcomes, is clinical significance. To further distinguish between important constructs, the authors suggest incorporating as definitive the existing notion that clinical significance may refer to measures selected or interpreted by professionals or with respect to groups of clients. The term personal significance is introduced to refer to goals, variables, measures, and changes that are of demonstrated value to individual clients.

Consumer preference in ranking walking function utilizing the walking index for spinal cord injury II

STUDY DESIGN

Blinded rank ordering.

OBJECTIVE

To determine consumer preference in walking function utilizing the walking Index for spinal cord injury II (WISCI II) in individuals with spinal cord injury (SCI)from the Canada, the Italy and the United States of America.

METHOD

In all, 42 consumers with incomplete SCI (25 cervical, 12 thoracic, 5 lumbar) from Canada (12/42), Italy (14/42) and the United States of America (16/42) ranked the 20 levels of the WISCI II scale by their individual preference for walking. Subjects were blinded to the original ranking of the WISCI II scale by clinical scientists. Photographs of each WISCI II level used in a previous pilot study were randomly shuffled and rank ordered. Percentile, conjoint/cluster and graphic analyses were performed.

RESULTS

All three analyses illustrated consumer ranking followed a bimodal distribution. Ranking for two levels with physical assistance and two levels with a walker were bimodal with a difference of five to six ranks between consumer subgroups (quartile analysis). The larger cluster (N=20) showed preference for walking with assistance over the smaller cluster (N=12), whose preference was walking without assistance and more devices. In all, 64% (27/42) of consumers ranked WISCI II level with no devices or braces and 1 person assistance higher than multiple levels of the WISCI II requiring no assistance. These results were unexpected, as the hypothesis was that consumers would rank independent walking higher than walking with assistance.

CONCLUSION

Consumer preference for walking function should be considered in addition to objective measures in designing SCI trials that use significant improvement in walking function as an outcome measure.

Minimum clinically important differences in the Cervical Spine Outcomes Questionnaire: results from a national multicenter study of patients treated with anterior cervical decompression and arthrodesis

BACKGROUND

The minimum clinically important difference is a clinically relevant threshold of improvement. A substantial clinical benefit is a threshold of change that correlates with clinically important improvement. The Cervical Spine Outcomes Questionnaire is a disease-specific, patient-reported outcomes instrument that was developed to be sensitive to changes associated with surgical treatment for degenerative cervical disc disease. To determine thresholds for change in these domain scores that are important from the patient's perspective, we estimated the minimum clinically important difference and substantial clinical benefit values for this questionnaire's domain scores.

METHODS

We evaluated 252 patients from the Cervical Spine Research Society Outcomes Study at their six-month follow-up visits after anterior cervical spine decompression and arthrodesis. Using a receiver operating characteristics curve, with the health transition item of the Short Form-36 as an anchor, we determined that the minimum clinically important difference (the value that maximized sensitivity and specificity to differentiate the "somewhat better" and "much better" responses from others) and the substantial clinical benefit (the value that maximized sensitivity and specificity to differentiate the "much better" response from others) for our questionnaire's domain scores. Responses were scaled between 0 and 1 point; higher scores denoted more severe impairment. Patient and clinical characteristics were tested to determine their influence on score changes.

RESULTS

The minimum clinically important difference ranged from 0.13 point (for functional disability) to 0.24 point (for arm/shoulder pain). The substantial clinical benefit score ranged from 0.20 point (for functional disability or physical symptoms other than pain) to 0.30 point (for neck or arm/shoulder pain). Age, sex, and duration of current symptoms were not associated with change in our questionnaire's domain scores.

CONCLUSIONS

A 0.13-point change in the functional disability domain score indicated a clinically important difference in a self-reported outcome after anterior cervical spine surgery. A 0.30-point change in neck pain after surgery indicated a clinically important clinical benefit. This information, coupled with previous reports of the psychometric stability of the Cervical Spine Outcomes Questionnaire, should increase the clinical utility of this patient-reported outcomes instrument.

Clinimetrics Corner: The Minimal Clinically Important Change Score (MCID): A Necessary Pretense

Minimal clinically important differences (MCID) are patient derived scores that reflect changes in a clinical intervention that are meaningful for the patient. At present, there are a number of different methods to obtain an MCID, as there a number of different factors that can influence the MCID value. This clinimetric corner outlines the hidden challenges associated with identifying a viable MCID and possible suggestions to improve the future development of these single scores.

Opening the black box of cancer patients' quality-of-life change assessments: a think-aloud study examining the cognitive processes underlying responses to transition items

Transition items are a popular approach to determine the clinical significance of patient-reported change. These items assume that patients (1) arrive at a change evaluation by comparing posttest and pretest functioning, and (2) accurately recall their pretest functioning. We conducted cognitive think-aloud interviews with 25 cancer patients prior to and following radiotherapy. Two researchers independently analysed their responses using an analysis scheme based on cognitive process models of Tourangeau et al. and Rapkin and Schwartz. In 112 of the 164 responses to transition items, patients compared current and prior functioning. However, in 104 of these responses, patients did not refer to their functioning at pretest and/or posttest according to transition design's first assumption, but rather used a variety of time frames. Additionally, in 79 responses, the time frame employed and/or description of prior functioning provided differed from those employed in the corresponding pretest items. Transition design's second assumption was therefore not in line with the patients' cognitive processes. Our findings demonstrate that in interpreting transition assessments, one needs to be aware that patients provide change assessments, which are not necessarily based on the cognitive processes intended by researchers and health care providers.

Quadriceps strength and weight acceptance strategies continue to improve two years after anterior cruciate ligament reconstruction

The anterior cruciate ligament (ACL) is the most commonly-injured knee ligament during sporting activities. After injury, most individuals experience episodes of the knee giving way during daily activities (non-copers). Non-copers demonstrate asymmetrical quadriceps strength and movement patterns, which could have long-term deleterious effects on the integrity of the knee joint. The purpose of this study was to determine if non-copers resolve their strength and movement asymmetries within two years after surgery. 26 Non-copers were recruited to undergo pre-operative quadriceps strength testing and 3-dimensional gait analysis. Subjects underwent surgery to reconstruct the ligament followed by physical therapy focused on restoring normal range of motion, quadriceps strength, and function. Subjects returned for quadriceps strength testing and gait analysis six months and two years after surgery. Acutely after injury, quadriceps strength was asymmetric between limbs, but resolved six months after surgery. Asymmetric knee angles, knee moments, and knee and hip power profiles were also observed acutely after injury and persisted six months after surgery despite subjects achieving symmetrical quadriceps strength. Two years after surgery, quadriceps strength in the involved limb continued to improve and most kinematic and kinetic asymmetries resolved. These findings suggest that adequate quadriceps strength does not immediately resolve gait asymmetries in non-copers. They also suggest that non-copers have the capacity to improve their quadriceps strength and gait symmetry long after ACL reconstruction.

Retrospective study of the effect of disease progression on patient reported outcomes in HER-2 negative metastatic breast cancer patients

BACKGROUND

This retrospective study evaluated the impact of disease progression and of specific sites of metastasis on patient reported outcomes (PROs) that assess symptom burden and health related quality of life (HRQoL) in women with metastatic breast cancer (mBC).

METHODS

HER-2 negative mBC patients (n = 102) were enrolled from 7 U.S. community oncology practices. Demographic, disease and treatment characteristics were abstracted from electronic medical records and linked to archived Patient Care Monitor (PCM) assessments. The PCM is a self-report measure of symptom burden and HRQoL administered as part of routine care in participating practices. Linear mixed models were used to examine change in PCM scores over time.

RESULTS

Mean age was 57 years, with 72% of patients Caucasian, and 25% African American. Median time from mBC diagnosis to first disease progression was 8.8 months. Metastasis to bone (60%), lung (28%) and liver (26%) predominated at initial metastatic diagnosis. Results showed that PCM items assessing fatigue, physical pain and trouble sleeping were sensitive to either general effects of disease progression or to effects associated with specific sites of metastasis. Progression of disease was also associated with modest but significant worsening of General Physical Symptoms, Treatment Side Effects, Acute Distress and Impaired Performance index scores. In addition, there were marked detrimental effects of liver metastasis on Treatment Side Effects, and of brain metastasis on Acute Distress.

CONCLUSIONS

Disease progression has a detrimental impact on cancer-related symptoms. Delaying disease progression may have a positive impact on patients' HRQoL.

Symptom Burden and Quality of Life in Patients with Follicular Lymphoma undergoing Maintenance Treatment with Rituximab Compared with Observation

BACKGROUND

The impact on health related quality of life (HRQoL) of rituximab maintenance (R-M) versus observation (OBS) after induction for treatment of follicular lymphoma (FL) is unclear.

METHODS

We reviewed the charts of 137 patients (53% female, 87% White, age 61.0 ± 12.4 years) who received either R-M (n = 53) or OBS (n = 84) after chemotherapy induction for newly diagnosed FL at community oncology practices within the US. Patients (65% with advanced disease; 48% with a high FLIPI score [3-5]) had completed ≥1 Patient Care Monitor HRQoL survey in the period following front-line therapy, and were excluded if they had progressed during front-line therapy.

RESULTS

Linear mixed models showed that postinduction, most symptoms were stable, with patients on R-M reporting HRQoL that was equal to that reported by OBS patients.

CONCLUSIONS

Among R-M patients, receipt of rituximab was associated with improved psychological symptoms.

Cost-effectiveness of transforaminal lumbar interbody fusion for Grade I degenerative spondylolisthesis

OBJECT

Transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis-associated back and leg pain is associated with improvement in pain, disability, and quality of life. However, given the rising health care costs associated with spinal fusion procedures and varying results of recent cost-utility studies, the cost-effectiveness of TLIF remains unclear. The authors set out to assess the comprehensive costs of TLIF at their institution and to determine its cost-effectiveness in the treatment of degenerative spondylolisthesis.

METHODS

Forty-five patients undergoing TLIF for Grade I degenerative spondylolisthesis-associated back and leg pain after 6-12 months of conservative therapy were included. The authors assessed the 2-year back pain visual analog scale (VAS) score, leg pain VAS score, Oswestry Disability Index, and total back-related medical resource utilization, missed work, and health-state values (quality-adjusted life years [QALYs], calculated from EQ-5D with US valuation). Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). The mean total 2-year cost per QALY gained after TLIF was assessed.

RESULTS

Compared with preoperative health states reported after at least 6 months of medical management, a significant improvement in back pain VAS score, leg pain VAS score, and Oswestry Disability Index was observed 2 years after TLIF, with a mean 2-year gain of 0.86 QALYs. The mean ± SD total 2-year cost of TLIF was $36,836 ± $11,800 (surgery cost, $21,311 ± $2800; outpatient resource utilization cost, $3940 ± $2720; indirect cost, $11,584 ± $11,363). Transforaminal lumbar interbody fusion was associated with a mean 2-year cost per QALY gained of $42,854.

CONCLUSIONS

Transforaminal lumbar interbody fusion improved pain, disability, and quality of life in patients with degenerative spondylolisthesis-associated back and leg pain. The total cost per QALY gained for TLIF was $42,854 when evaluated 2 years after surgery with Medicare fees, suggesting that TLIF is a cost-effective treatment of lumbar spondylolisthesis.

Assessing dimensionality and responsiveness of outcomes measures for patients with low back pain

OBJECTIVE

To provide a systematic literature review of the responsiveness of patient-reported health outcomes measures for the evaluation of low back pain (LBP).

METHODS AND DESIGN

Searches of MEDLINE and EMBASE were performed for articles published in English through June 29, 2009 using the search terms "back pain" or "low back pain" and "questionnaires" or "instrument" or "survey" or "measure" or "patient report outcome." Information on responsiveness was gathered through additional measure-specific searches that included the measure name, first author of the original paper, and "respons*" or "sensit*." Responsiveness was determined based on use of a receiver operating characteristics curve or effect size statistics.

RESULTS

Of 43 identified measures, 31 were reported as being responsive to treatment or clinical change, 25 of which were evaluated for responsiveness using methods considered adequate. When considering both the responsiveness evaluation and the underlying factor structure, 13 measures were identified as being adequately validated for use in evaluating responsiveness in the research or clinical practice setting. The majority of the LBP outcome assessment studies were comprised of patients undergoing physical and interventional therapies from clinical practice and clinical trials. The Roland Morris Disability Questionnaire and the Oswestry Disability Index were the most comprehensively validated measures with respect to responsiveness.

CONCLUSIONS

We identified 13 measures of LBP that can be used to evaluate responsiveness to change. Choice of a measure warrants careful evaluation of its construct and responsiveness properties in order to maximize the observed impact on pain and functional improvement in subjects with LBP.

Baseline dependency of minimal clinically important improvement

BACKGROUND

Minimal clinically important improvement (MCII) is the smallest outcome measure change important to patients. Research suggests that MCII is dependent on patients' baseline functional status measures.

OBJECTIVE

The purposes of this study were: (1) to confirm whether MCII is dependent on patients' admission scores and (2) to test whether MCII is dependent on selected demographic characteristics.

STUDY DESIGN AND SETTING

This was a prospective, longitudinal, observational cohort study of 6,651 patients with orthopedic knee impairments treated in 332 outpatient rehabilitation clinics in 27 states in the United States.

OUTCOME MEASURES

Patient self-reports of functional status (FS) from the Lower Extremity Functional Scale were assessed using a computerized adaptive testing application (0-100 scale).

METHODS

An anchored-based longitudinal method, with a 15-point Likert-type scale (-7 to +7), was used to provide a global rating of change (GROC). The MCII threshold for the GROC was defined at a cut-score of +3 or greater and was determined using nonparametric receiver operating characteristic curve analysis for each of the following variables: sex, symptom acuity, age group, and quartile of baseline FS scores.

RESULTS

The results showed that MCII was dependent on patient baseline and demographic characteristics. Patients who were male, were younger, had more-acute symptoms, or had lower FS scores at admission required more FS change to report meaningful change.

LIMITATIONS

As this study was a secondary analysis, how the length of treatment mediated the relationship between the independent and dependent variables was unclear.

CONCLUSIONS

Although a single MCII index may provide a standard cut-score defining the smallest FS change that is meaningful to patients, researchers and clinicians should be aware that MCII is context specific and not a fixed attribute. Current results may help researchers, clinicians, and policy makers to interpret FS change related to the importance of the change to the patient.

A comparison of 3 methodological approaches to defining major clinically important improvement of 4 performance measures in patients with hip osteoarthritis

STUDY DESIGN

Prospective cohort study.

OBJECTIVES

To establish the major clinically important improvement (MCII) of the timed up-and-go test (TUG), 40-meter self-paced walk test (40-m SPWT), 30-second chair stand (30 CST), and a 20-cm step test in patients with hip osteoarthritis (OA) undergoing physiotherapy treatment. As a secondary aim, a comparison of methods was employed to evaluate the effect of method on the reported MCII.

BACKGROUND

Minimal clinically important difference scores are commonly used by rehabilitation professionals to determine patient response following treatment. A gold standard for calculating MCII has yet to be determined, which has resulted in problems of interpretation due to varied results.

METHODS

As part of a randomized controlled trial, 65 patients were randomized into a physiotherapy treatment group for hip OA, in which they completed 4 physical performance measures at baseline and 9 weeks. Upon completion of physiotherapy, patients assessed their response to treatment on a 15-point global rating of change scale (GRCS). MCII was estimated using 3 variations of an anchor-based method, based on the patient's opinion.

RESULTS

A comparison of 3 methods resulted in the following change scores being best associated with our definition of MCII: a reduction equal to or greater than 0.8, 1.4, and 1.2 seconds for the TUG; an increase equal to or greater than 0.2, 0.3, and 0.2 m/s for the 40-m SPWT; an increase equal to or greater than 2.0, 2.6, and 2.1 repetitions for the 30 CST; an increase equal to or greater than 5.0, 12.8, and 16.4 steps for the 20-cm step test.

CONCLUSION

The variation in methods provided very different results. This illustrates the importance of comparing methodologies and reporting a range of values associated with the MCII, as such values vary, depending upon the methodology chosen.

The lack of association between changes in functional outcomes and work retention in a chronic disabling occupational spinal disorder population: implications for the minimum clinical important difference

STUDY DESIGN

A prospective study in a chronic pain/ disability population, relating changes in the Oswestry Disability Index (ODI), as well as the Mental Component Summary (MCS) and Physical Component Summary (PCS) of the Short Form-36 (SF-36), to work retention (WR) status at 1-year postrehabilitation.

OBJECTIVE

To explore the relationship between WR status and change in ODI, and the MCS and PCS of the SF-36, and determine if an MCID can be identified using WR as an external criterion for the group of patients under consideration.

SUMMARY OF BACKGROUND DATA

Clinically meaningful change may be defined through self-report, physician- based, or objective criteria of improvement, although most assessments have been based on self-report assessment of improvement. The disability occurring after work-related spinal disorders lends itself to anchoring self-report measures to objective work status outcomes 1-year post-treatment. Additional research is needed to evaluate the relationship between change and objective markers of improvement.

METHODS

A consecutive cohort of patients (n = 2024) with chronic disabling occupational spinal disorders completed an interdisciplinary functional restoration program, and underwent a structured clinical interview for objective, socioeconomic outcomes at 1-year post-treatment. The average percent change in the ODI, as well as the MCS and PCS of the SF-36, were calculated for patients who successfully retained work and those who had not after completing a functional restoration program. Predictive ability of the percent change scores were evaluated through logistic regression analysis.

RESULTS

No percent difference variables were strong predictors of WR status 1-year following treatment.

CONCLUSION

The current analyses suggest that the ODI and SF-36 MCS and PCS measures are not responsive at the individual patient level when WR data are used as the external criterion using an anchor-based approach. This finding contrasts to reports of responsiveness based on distributional methods, or methods using self-report anchors of change.

Utility of minimum clinically important difference in assessing pain, disability, and health state after transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis

OBJECT

Outcome studies for spine surgery rely on patient-reported outcomes (PROs) to assess treatment effects. Commonly used health-related quality-of-life questionnaires include the following scales: back pain and leg pain visual analog scale (BP-VAS and LP-VAS); the Oswestry Disability Index (ODI); and the EuroQol-5D health survey (EQ-5D). A shortcoming of these questionnaires is that their numerical scores lack a direct meaning or clinical significance. Because of this, the concept of the minimum clinically important difference (MCID) has been put forth as a measure for the critical threshold needed to achieve treatment effectiveness. By this measure, treatment effects reaching the MCID threshold value imply clinical significance and justification for implementation into clinical practice.

METHODS

In 45 consecutive patients undergoing transforaminal lumbar interbody fusion (TLIF) for low-grade degenerative lumbar spondylolisthesis-associated back and leg pain, PRO questionnaires measuring BP-VAS, LPVAS, ODI, and EQ-5D were administered preoperatively and at 2 years postoperatively, and 2-year change scores were calculated. Four established anchor-based MCID calculation methods were used to calculate MCID, as follows: 1) average change; 2) minimum detectable change (MDC); 3) change difference; and 4) receiver operating characteristic curve analysis for two separate anchors (the health transition index [HTI] of the 36-Item Short Form Health Survey [SF-36], and the satisfaction index).

RESULTS

All patients were available at the 2-year follow-up. The 2-year improvements in BP-VAS, LP-VAS, ODI, and EQ-5D scores were 4.3 ± 2.9, 3.8 ± 3.4, 19.5 ± 11.3, and 0.43 ± 0.44, respectively (mean ± SD). The 4 MCID calculation methods generated a range of MCID values for each of the PROs (BP-VAS, 2.1-5.3; LP-VAS, 2.1-4.7; ODI, 11-22.9; and EQ-5D, 0.15-0.54). The mean area under the curve (AUC) for the receiver operating characteristic curve from the 4 PRO-specific calculations was greater for the HTI versus satisfaction anchor (HTI [AUC 0.73] vs satisfaction [AUC 0.69]), suggesting HTI as a more accurate anchor.

CONCLUSIONS

The TLIF-specific MCID is highly variable based on calculation technique. The MDC approach with the SF-36 HTI anchor appears to be most appropriate for calculating MCID because it provided a threshold above the 95% CI of the unimproved cohort (greater than the measurement error), was closest to the mean change score reported by improved and satisfied patients, and was least affected by the choice of anchor. Based on the MDC method with HTI anchor, MCID scores following TLIF are 2.1 points for BP-VAS, 2.8 points for LP-VAS, 14.9 points for ODI, and 0.46 quality-adjusted life years for EQ-5D.

Health-related quality of life improvements in patients undergoing lumbar spinal fusion as a revision surgery

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVE

To investigate health-related quality of life improvements in patients undergoing lumbar fusion to revise a previous lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

Spinal fusion is often used as a surgical intervention in patients who have previously undergone lumbar surgery. Prior studies suggest results that are inferiorto primary fusions. However, most of these studies are based on subjective surgeon evaluations, lack patient-reported outcomes, and include various diagnoses such as prior discectomy, adjacent level degeneration, and nonunion.

METHODS

From a single-center database, we identified 171 patients who underwent lumbar fusion to revise a previous lumbar spine surgery. All had prospectively collected outcome measures at a minimum 2-year follow-up. The study group included 91 patients who had previous discectomy or laminectomy, 42 patients undergoing revision for adjacent segment degeneration (ASD) and 38 patients undergoing revision for nonunion. All patients completed the Oswestry Disability Index (ODI), MOS Short Form 36 (SF-36), and back and leg pain numerical rating scores before surgery and at 1 and 2 years after surgery. We compared mean changes in outcome measures and percentage of patients reaching the minimum clinically important difference (MCID) threshold in the 3 groups. Logistic regression analysis was performed to identify preoperative factors which could predict significant improvement.

RESULTS

Statistically significant improvements were noted in back pain, leg pain, and ODI in all 3 groups. Postdecompression and ASD patients demonstrated significant improvements in SF-36 PCS at 2 years, while nonunion patients did not. A total of 49% of postdecompression patients, 38% of ASD patients, and 29% of nonunion patients reached the MCID for ODI. About 46% of postdecompression patients, 40% of ASD patients, and 24% of nonunion patients reached the MCID for SF-36 PCS. Significant improvement from index surgery was the only factor which able to predict reaching the MCID for ODI, while worker's compensation and narcotic use predicted failure to reach the MCID for SF-36 PCS.

CONCLUSION

The current study demonstrates that patients undergoing lumbar fusion as a revision of a prior lumbar surgery can expect only modest improvements in health-related quality of life. Postdecompression patients achieved moderate improvements in clinical outcome measures, whereas ASD and nonunion patients showed only modest improvements. Further investigation is needed to identify preoperative predictors that will assist the selection of patients who will benefit from revision lumbar fusion.

Long-term reduction in pain and disability after surgery with the interspinous device for intervertebral assisted motion (DIAM) spinal stabilization system in patients with low back pain: 4-year follow-up from a longitudinal prospective case series

Patients with low back pain (LBP) suffer chronic disability. In 40% of LBP patients degenerative disc disease (DDD) seems to be the cause. This prospective case series assessed the efficacy of the interspinous device for intervertebral assisted motion (DIAM™) in patients with LBP resulting from DDD. All patients were initially assessed by physical examinations, magnetic resonance imaging, dynamic X-rays and provocative discography. Eligible patients (n = 52) had LBP for a minimum of 4 months, and received surgery with the DIAM™ system 2-4 weeks after diagnosis. Patients were evaluated pre-/post-operatively for pain severity using a visual analogue scale (VAS), and for dysfunction and disability with the Roland-Morris Disability Questionnaire (RMDQ). VAS and RMDQ score changes were assessed using the appropriate contrasts and Bonferroni-corrected P values. As a result, significant (P < 0.0001) pain score reductions were observed between baseline values, and 2 (3.7, 95% CI 3.1; 4.2) and 48 (3.1, 95% CI 2.5; 3.6) months follow-up (intent-to-treat population). Disability scores were significantly (P < 0.0001) reduced between baseline and 2 (8.6, 95% CI 7.4; 9.9) and 48 (7.5, 95% CI 6.1; 8.9) months. Disability scores were similar from months 2 to 48. At 48 months, 67.3% of patients reached the minimum clinically important difference (MCID; ≥1.5-unit improvement) in VAS score and 78.9% of patients reached the MCID (≥30% improvement) in RMDQ score. No complications were associated with surgery. In conclusion, patients with LBP treated with the interspinous DIAM™ system showed significant and clinically meaningful improvements in pain and disability for up to 4 years.

Performance tests in people with chronic low back pain: responsiveness and minimal clinically important change

STUDY DESIGN

Cohort study.

OBJECTIVE

To assess the responsiveness and minimal clinically important change (MCIC) of 6 commonly-used performance tests (5-minute walking, 50-ft walking, sit-to-stand, 1 minute stair climbing, loaded forward reach, Progressive Isoinertial Lifting Evaluation).

SUMMARY OF BACKGROUND DATA

Performance tests are used to evaluate physical function in people with low back pain. Little is known about their clinimetric properties.

METHODS

Performance tests were administered in people with chronic nonspecific low back pain (n = 198) before and after 10 weeks of treatment. At 10 weeks, the global perceived effect scale was used to determine if participants judged themselves as worsened, unchanged, or improved. The mean change scores for each performance test were calculated. A performance test was considered responsive if the area under the receiver operating characteristic curve (AUC) was equal to or greater than 0.70. We used 2 methods to evaluate MCIC: the optimal cut-off point based on the receiver operating characteristic curve, which takes into account both sensitivity and specificity, and the minimal detectable change for improvement, which considers test specificity only.

RESULTS

In general, the mean change scores were the smallest in participants who judged themselves worsened and largest in those reporting to be improved. Sit-to-stand (AUC = 0.75) and stair climbing (AUC = 0.72) were the only performance tests that showed adequate responsiveness. For sit-to-stand, the MCIC ranged from 4.1 to 9.8 seconds (19%-45% of the mean baseline score). For stair climbing, the MCIC ranged from 14.5 to 23.9 steps (19%-31% of the mean baseline score).

CONCLUSION

Only 2 of the 6 performance tests were responsive. Both had acceptable MCIC values. Developing individualized performance tests might partly overcome the general lack of responsiveness of performance tests. Future research should focus on the clinimetric testing of performance tests in subgroups.

Acupuncture for treating dry eye: a randomized placebo-controlled trial

PURPOSE

To evaluate the efficacy and safety of acupuncture for ocular symptoms, tear film stability and tear secretion in dry eye patients.

METHODS

This is a randomized, patient-assessor blinded, sham acupuncture controlled trial. Forty-two participants with defined moderate to severe dry eye underwent acupuncture treatment three times a week for 3 weeks. Seventeen standard points (GV23; bilateral BL2, GB14, TE23, Ex1, ST1 and GB20; and unilateral SP3, LU9, LU10 and HT8 on the left for men and right for women) with 'de qi' manipulation for the verum acupuncture group and seventeen sham points of shallow penetration without other manipulation for the sham group were applied during the acupuncture treatment. Differences were measured using the ocular surface disease index (OSDI), the visual analogue scale (VAS) of ocular discomfort, the tear film break-up time (BUT) and the Schimer I test with anaesthesia. In addition, adverse events were recorded.

RESULTS

There were no statistically significant differences between results on the OSDI, VAS, BUT or Schimer I tests from baseline between the verum and sham acupuncture groups. However, results from the within-group analysis showed that the OSDI and VAS in both groups and the BUT in the verum acupuncture group were significantly improved after 3 weeks of treatment. No adverse events were reported during this trial.

CONCLUSION

Both types of acupuncture improved signs and symptoms in dry-eye patients after a 4-week treatment. However, verum acupuncture did not result in better outcomes than sham acupuncture.

The minimum clinically important difference in Scoliosis Research Society-22 Appearance, Activity, And Pain domains after surgical correction of adolescent idiopathic scoliosis

STUDY DESIGN

Longitudinal cohort.

OBJECTIVE

To determine the minimum clinically important difference (MCID) of the Scoliosis Research Society (SRS)-22 Appearance, Activity, and Pain domains in patients with adolescent idiopathic scoliosis undergoing surgical correction of their spinal deformity.

SUMMARY OF BACKGROUND DATA

The MCID, a threshold of improvement that is clinically relevant to the individual patient, is increasingly used to evaluate treatment effectiveness. MCID values for the SRS-22 domains have not been determined.

METHODS

Patients with adolescent idiopathic scoliosis who underwent surgical correction and had completed SRS-22 before operation and the SRS-30 and Scoliosis Appearance Questionnaire (SAQ) at 1 year after operation from a multicenter database for pediatric scoliosis were identified. The SAQ is a modification of the Walter Reed Visual Assessment Scale and is used to assess the patient's perception of their spinal deformity. Paired sample t tests were used to compare preoperative and 1-year postoperative scores. Spearman correlations were used to evaluate associations between domain scores and summed responses to anchors for Appearance, Activity, and Pain. MCID values for the SRS-22 domains were determined using receiver operating characteristic curve analysis, with summed responses to anchor questions 23 to 30 of the SRS-30 and items 26 and 32 of the SAQ.

RESULTS

There were 735 women and 152 men with a mean age of 14.3 years and a mean Cobb angle of 53°. There was a statistically significant difference between paired preoperative and 1-year SRS domain scores. Analysis of variance showed a statistically significant difference between the summed responses to the anchors. The MCID was 0.20 for the Pain domain (area under the curve [AUC] = 0.723), 0.08 for Activity (AUC = 0.648), and 0.98 for Appearance (AUC = 0.629). The MCID for activity was less than the standard error of measurement.

CONCLUSION

The MCID for the Pain domain was 0.20 and 0.98 for Appearance. Because these patients were generally in good health, a minimal though significant change in activity was observed, such that the calculated MCID was within the measurement error. As expected, the largest and most important change was in the Appearance domain. Future studies are needed to determine the MCID for the mental domain and the total SRS score and to further validate the MCID values in this study.

Minimal clinically important differences of disease activity indices in childhood-onset systemic lupus erythematosus

OBJECTIVE

To determine the minimal clinically important differences (MCIDs) of validated measures of systemic lupus erythematosus (SLE) disease activity in childhood-onset SLE.

METHODS

Childhood-onset SLE patients (n = 98) were followed every 3 months for up to 7 visits (n = 623 total visits). Disease activity measures (European Consensus Lupus Activity Measure, Systemic Lupus Erythematosus Disease Activity Index, Systemic Lupus Activity Measure, British Isles Lupus Assessment Group, and Responder Index for Lupus Erythematosus [RIFLE]) were completed at the time of each visit. Physician-rated changes in the disease course (clinically relevant improvement, no change, clinically relevant worsening) between visits served as the criterion standard.

RESULTS

MCIDs defined by mean change scores with improvement and worsening, or those based on the standard error of measurement with stable disease, were both small and did not discriminate well between disease courses (detection rates for improvement or worsening were all <55%). MCIDs based on discriminant and classification analyses yielded similar results. Alternative MCIDs, defined by a 70% predicted probability of improvement or worsening as per the discrimination analysis, were larger but underestimated the proportion of patients with change. The RIFLE only correctly identified 26% and 8% of episodes of clinically important worsening and improvement of childhood-onset SLE, respectively.

CONCLUSION

The MCIDs of childhood-onset SLE disease activity measures are often small but similar to those reported for adults with SLE. Therefore, even small changes in disease activity scores can be clinically relevant. Low correct detection rates of these MCID thresholds for changes in disease course support the notion that worsening and improvement with childhood-onset SLE, or its response to therapy, is unlikely to be captured adequately by validated measures of disease activity alone.

Randomized clinical trials in orthopaedic surgery: strategies to improve quantity and quality

Randomized clinical trials (RCTs) generally provide the highest quality and least biased evidence for treatment effectiveness. Relatively few high-quality RCTs have been published in the orthopaedic literature. Barriers to increasing the quantity of trials include the orthopaedic culture, patient preferences, and the availability of treatment outside trials. Challenges to conducting better quality trials include sample size, random allocation, and blinding. Undertaking more high-quality trials can improve the evidence available for determining treatment effectiveness, resulting in better patient care.

Two- to 4-year follow-up to a comparison of home versus physical therapy-supervised rehabilitation programs after anterior cruciate ligament reconstruction

BACKGROUND

There have been no long-term follow-up studies comparing a predominantly home-based rehabilitation program with a standard physical therapy program after anterior cruciate ligament (ACL) reconstruction. Demonstrating the long-term success of such a cost-effective program would be beneficial to guide future rehabilitation practice.

PURPOSE

To determine whether there were any differences in long-term outcome between recreational athletes who performed a physical therapy-supervised rehabilitation program and those who performed a primarily home-based rehabilitation program in the first 3 months after ACL reconstruction.

STUDY DESIGN

Randomized clinical trial; Level of evidence, 1.

METHODS

Patients were randomized before ACL reconstruction surgery to either the physical therapy-supervised (17 physical therapy sessions) or home-based (4 physical therapy sessions) program. Eighty-eight of the original 129 patients returned 2 to 4 years after surgery to assess their long-term clinical outcomes. Primary outcome was the ACL quality of life questionnaire (ACL QOL). Secondary outcomes were bilateral difference in knee extension and flexion range of motion, sagittal plane knee laxity, relative quadriceps and hamstring strength, and objective International Knee Documentation Committee score. Unpaired t tests and a chi-square test were used for the comparisons.

RESULTS

The home-based group had a significantly higher mean ACL QOL score (80.0 +/- 16.2) than the physical therapy-supervised group (69.9 +/- 22.0) a mean of 38 months after surgery (P = .02, 95% confidence interval [CI]: 1.7, 18.4). The mean change in ACL QOL score from before surgery to follow-up was not significantly different between the groups (physical therapy = 40.0, home = 45.8, P = .26, 95% CI: -15.8, 4.4). There were no significant differences in the secondary outcome measures.

CONCLUSION

This long-term study upholds the short-term findings of the original randomized clinical trial by demonstrating that patients who participate in a predominantly home-based rehabilitation program in the first 3 months after ACL reconstruction have similar 2- to 4-year outcomes compared with those patients who participate in a more clinically supervised program.

Neck Disability Index, short form-36 physical component summary, and pain scales for neck and arm pain: the minimum clinically important difference and substantial clinical benefit after cervical spine fusion

BACKGROUND CONTEXT

The Neck Disability Index (NDI), the short form-36 (SF-36) physical component summary (PCS), and pain scales for arm and neck pain are increasingly used to evaluate treatment effectiveness after cervical spine surgery. The minimum clinically important difference (MCID) is a threshold of improvement that is clinically relevant to the patient. However, the true goal is to provide the patient with a substantial clinical benefit (SCB).

PURPOSE

This study determines the MCID and SCB using common anchor-based methods for NDI, PCS, and pain scales for arm and neck pain in patients undergoing cervical spine fusion for degenerative disorders.

STUDY DESIGN/SETTING

The study setting is a longitudinal cohort in a multisurgeon spine specialty clinic.

PATIENT SAMPLE

The sample comprises 505 patients who underwent a cervical fusion for degenerative spine conditions and who have prospectively collected outcome scores with a minimum 1-year follow-up.

OUTCOME MEASURES

The outcome measures of the study were NDI, SF-36, and numeric rating scales for arm and neck pain.

METHODS

The MCID and SCB values for NDI, PCS, and pain scales for arm and neck pain were determined using receiver operating characteristic (ROC) curve analysis with the Health Transition Item of the SF-36 as an anchor. The Health Transition Item asks a patient "Compared to one year ago, how would you rate your health in general now?" with answers ranging from "Much Better," "Somewhat Better," "About the Same," "Somewhat Worse," to "Much Worse." An ROC curve was constructed for each measure. The ROC curve-derived MCID was the change score with equal sensitivity and specificity to distinguish the "Somewhat Better" from the "About the Same" patients. The ROC curve-derived SCB was the change score with equal sensitivity and specificity to distinguish the "Much Better" from the "Somewhat Better" patients. Distribution-based methods including the standard error of the mean and the minimum detectable change were also used to calculate MCID.

RESULTS

The calculated MCID is 7.5 for the NDI, 4.1 for SF-36 PCS, and 2.5 for arm and neck pain. The calculated SCB is 9.5 for the NDI, 6.5 for SF-36 PCS, and 3.5 for arm and neck pain.

CONCLUSIONS

Patients with an eight-point decrease in NDI, a 4.1-point increase in PCS, and a three-point decrease in arm or neck pain can detect a minimally clinically important change. Patients with a 10-point decrease in NDI, a 6.5-point increase in PCS, and a four-point decrease in arm or neck pain can detect an SCB after cervical spine fusion.

Modification of the upper limb functional index to a three-point response improves clinimetric properties

STUDY DESIGN

Observational two-stage.

INTRODUCTION

To achieve optimal clinimetric properties for outcome measures, both practical and psychometric, ongoing improvements are required.

PURPOSE OF THE STUDY

To evaluate if the Upper Limb Functional Index (ULFI) clinimetric properties are improved by modification to a three-point response option and to verify the factor structure.

METHODS

Stage 1, calibration (n=139) used ULFI dichotomous responses, and stage 2, validation (n=117) used a three-point response option. The clinimetric properties were compared in physical therapy outpatients with the QuickDASH as the reference standard. Repeated measurements were made at two to four weekly intervals.

RESULTS

The ULFI three-point response option improved reliability [intraclass correlation coefficient (2,1)=0.98], internal consistency (alpha=0.92), QuickDASH concurrent validity (r=0.86), and responsiveness. Minimal detectable change (90% confidence interval) was 7.9%, and factor structure was unidimensional. Missing responses were <0.5%, and practical characteristics were unchanged.

CONCLUSIONS

The enhanced reliability and reduced errors with unchanged practicality demonstrate the ULFI improvements through modification to a three-point response option.

LEVEL OF EVIDENCE

2c.

Validation of a new device to measure postsurgical scar adherence

BACKGROUND AND PURPOSE

Scarring after surgery can lead to a wide range of disorders. At present, the degree of scar adhesion is assessed manually and by ordinal scales. This article describes a new device (the Adheremeter) to measure scar adhesion and assesses its validity, reliability, and sensitivity to change.

DESIGN

This was a reliability and validity study.

SETTING

The study was conducted at the Scientific Institute of Veruno.

PARTICIPANTS AND METHODS

Two independent raters, a physical therapist and a physical therapist student, used the Adheremeter to measure scar mobility and contralateral normal skin in a sample of 25 patients with adherent postsurgical scars before (T1) and after (T2) physical therapy. Two indexes of scar mobility, the adherence's surface mobility index (SM(A)) and the adherence severity index (AS), were calculated. Their correlation with the Vancouver Scar Scale (VSS) and its pliability subscale (PL-VSS) was assessed for the validity analysis.

RESULTS

Both the SM(A) and the AS showed good-to-excellent intrarater reliability (intraclass correlation coefficient [ICC]=.96) and interrater reliability (SM(A): ICC=.97 and .99; AS: ICC=.87 and .87, respectively, at T1 and T2), correlated moderately with the VSS and PL-VSS only at T1 (r(s)=-.58 to -.66), and were able to detect changes (physical therapist/physical therapist student): z score=-4.09/-3.88 for the SM(A) and -4.32/-4.24 for the AS; effect size=0.6/0.4 for the SM(A) and 1.4/1.2 for the AS; standard error of measurement=4.59/4.79 mm(2) for the SM(A) and 0.05/0.06 for the AS; and minimum detectable change=12.68/13.23 mm(2) for the SM(A) and 0.14/0.17 for the AS.

LIMITATIONS

The measurement is based on the rater's evaluation of force to stretch the skin and on the patient's judgment of comfort.

DISCUSSION AND CONCLUSION

The Adheremeter showed a good level of reliability, validity, and sensitivity to change. Further studies are needed to confirm these results in larger cohorts and to assess the device's validity for other types of scars.

Testing minimal clinically important difference: consensus or conundrum?

BACKGROUND CONTEXT

Various methodologies have been used in attempting to elucidate a standard method for calculating minimal clinically important difference (MCID). A consensus-based decision (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials [IMMPACT] group) suggested a 30% reduction from baseline as a means to define the MCID of self-report back pain measures. Additionally, important psychometric issues need to be addressed regarding use of an independent measure of the same construct as an external criterion, instead of simply using another self-report measure, when using an anchor-based approach to MCID.

PURPOSE

The purpose was to test the validity of recently published guidelines regarding MCID using self-report back pain measures and objective socioeconomic outcomes.

STUDY DESIGN/SETTING

This is a prospective study assessing change scores on commonly used spinal pain assessment measures in patients with chronic disabling occupational spinal disorders (CDOSDs) treated in a regional referral rehabilitation center performing interdisciplinary functional restoration.

PATIENT SAMPLE

The study consisted of consecutive cohort of patients (N=1,180) with CDOSDs completing a functional restoration program.

OUTCOMES MEASURES

Self-report measures including the Oswestry Disability Index (ODI) and the physical component summary (PCS) and mental component summary (MCS) of the Short Form-36 (SF-36) obtained before and after treatment, were compared with objective socioeconomically relevant outcomes obtained 1 year after treatment (ie, work status and additional health-care utilization), that were the external criteria for evaluating MCID.

METHODS

Pre- to posttreatment improvement was calculated separately for each measure, and subjects were divided into two groups based on the change in scores relative to baseline: 30% or greater versus less than 30% improvement. One-year posttreatment objective socioeconomic outcomes were used as independent external criteria relevant to the CDOSD population. This population is often studied as the most costly and problematic cohort in spine care.

RESULTS

The ODI and SF-36 MCS were not associated with any of the objective 1-year outcomes used as external criteria. Reduced post-rehabilitation health-care utilization (based on the percentage of patients pursuing health care from a new provider) was weakly associated with 30% or greater improvement on the SF-36 PCS, relative to patients whose scores changed by less than 30% relative to baseline (17.0% vs. 21.1%). The same was true for the ODI and return-to-work.

CONCLUSIONS

When objective and independent criteria are used (socioeconomic outcomes) in a CDOSD cohort, the 30% improvement in the ODI and SF-36 may not be a valid MCID index. This replicates similar conclusions made by an independent research group using a distribution-based approach to MCID. The validity of the MCID concept rests on future research using objective external criteria. Moreover, there remains a question whether the term "important" in MCID can be unequivocally and operationally defined as a reliable construct.

Plasma disc decompression compared with fluoroscopy-guided transforaminal epidural steroid injections for symptomatic contained lumbar disc herniation: a prospective, randomized, controlled trial

Object

Patients with radiculopathy, with or without back pain, often do not respond to conservative care and may be considered for epidural steroid injection therapy or a disc decompression procedure. Plasma disc decompression (PDD) using the Coblation SpineWand device is a percutaneous, minimally invasive interventional procedure. The purpose of this study was to evaluate clinical outcomes with PDD as compared with standard care using fluoroscopy-guided transforaminal epidural steroid injection (TFESI) over the course of 2 years.

Methods

This was a multicenter randomized controlled clinical study. Ninety patients (18–66 years old) who had sciatica (visual analog scale score ≥50) associated with a single-level lumbar contained disc herniation were enrolled. In all cases, their condition was refractory to initial conservative care and 1 epidural steroid injection had failed. Participants were randomly assigned to receive either PDD (46 patients) or TFESI (44 patients, up to 2 injections).

Results

The patients in the PDD Group had significantly greater reduction in leg pain scores and significantly improved Oswestry Disability Index and 36-Item Short Form Health Survey ([SF-36], physical function, bodily pain, social function, and physical components summary) scores than those in the TFESI Group. During the 2-year follow-up, 25 (56%) of the patients in the PDD Group and 11 (28%) of those in the TFESI Group remained free from having a secondary procedure following the study procedure (log-rank p = 0.02). A significantly higher percentage of patients in the PDD Group showed minimum clinically important change in scores for leg and back pain and SF-36 scores that exceeded literature-based minimum clinically important changes. Procedure-related adverse events, including injection site pain, increased leg or back pain, weakness, and lightheadedness, were observed in 5 patients in the PDD Group (7 events) and 7 in the TFESI Group (14 events).

Conclusions

In study patients who had radicular pain associated with a contained lumbar disc herniation, those patients treated with PDD had significantly reduced pain and better quality of life scores than those treated using repeated TFESI. In addition, significantly more PDD patients than TFESI patients avoided having to undergo a secondary procedure during the 2-year study follow-up.

Statistical and clinical significance, and how to use confidence intervals to help interpret both

Statistical significance is a statement about the likelihood of findings being due to chance. Classical significance testing, with its reliance on p values, can only provide a dichotomous result - statistically significant, or not. Limiting interpretation of research results to p values means that researchers may either overestimate or underestimate the meaning of their results. Very often the aim of clinical research is to trial an intervention with the intention that results based on a sample will generalise to the wider population. The p value on its own provides no information about the overall importance or meaning of the results to clinical practice, nor do they provide information as to what might happen in the future, or in the general population. Clinical significance is a decision based on the practical value or relevance of a particular treatment, and this may or may not involve statistical significance as an initial criterion. Confidence intervals are one way for researchers to help decide if a particular statistical result (whether significant or not) may be of relevance in practice.

Responsiveness of the Michigan Hand Outcomes Questionnaire and the Disabilities of the Arm, Shoulder, and Hand questionnaire in patients with hand injury

PURPOSE

To compare responsiveness of the Michigan Hand Outcomes Questionnaire (MHQ) with that of the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire in patients with hand injuries. We postulated that the MHQ may be more sensitive to functional changes in the hands, whereas the DASH questionnaire would have a closer association with days of disability.

METHODS

Patients with hand injuries were consecutively recruited from 2 community hospitals. Each patient was asked to complete out the MHQ, the DASH questionnaire, the satisfaction with their health-related quality of life (Sat-HRQOL) measure, and Chinese Health Questionnaire (CHQ), which is a measure of psychological stressors. Disability days were defined as the duration of restricted activities of daily living during the previous 4 weeks. Patients repeated the same questionnaires between 2 and 9 months after enrollment (average: 4 mo).

RESULTS

A total of 105 patients with hand injuries were recruited, and 50 of the 105 patients returned for the second evaluation. There were no statistical differences between responders and nonresponders for age, gender, disability days, the MHQ, the DASH questionnaire, the CHQ, or the Sat-HRQOL. Responsiveness was evaluated by effect sizes and standardized response means: Those for the MHQ were 0.84 and 1.05, and those for the DASH were 0.67 and 0.86, respectively. A mixed model analysis for repeated measurements of the 50 participants showed a significant influence of psychological factors (CHQ) for both the Sat-HRQOL and disability days. After adjustment for the effects of age, gender, and the CHQ, there was an increment of one Sat-HRQOL unit for an MHQ score increment of 3.2, whereas the score decrement for the DASH questionnaire was 3.3 units.

CONCLUSIONS

The MHQ might be slightly more sensitive to functional changes, but the DASH questionnaire seemed more correlated with disability days. Psychological factors are the strongest determinants of the HRQOL and disability.

Defining value in spine care

Spinal disorders are extremely common, debilitating, and costly to the payer and to society as a whole. The rate and cost of various spinal treatments are increasing at an astonishing rate, but it is unclear whether the resulting quality of spinal care is improving. Rather than focusing solely on quality improvement measures or cost-saving measures, there is a recent emphasis on the value of health care. Defining the value of spine care depends on a standardized, accurate method of measuring outcomes and costs. It is important that the outcomes measured are patient centered and that both the outcomes and costs are measured over time with long-term follow-up. The purpose of this article is to review current methods for measuring outcomes and propose a means by which the value of spine care can be more clearly defined.

Minimal detectable change and clinically important difference of the Stroke Impact Scale in stroke patients

OBJECTIVES

The purpose of this study was to establish the minimal detectable change (MDC) and clinically important differences (CIDs) of the physical domains of the Stroke Impact Scale (SIS) and to assess the proportions of patients' change scores exceeding the MDC and CIDs after stroke rehabilitation.

METHODS

Seventy-four patients received 1 of 3 treatments for 3 weeks and underwent clinical assessment before and after treatment. The MDC was calculated from the standard error of measurement to indicate a real change with 95% confidence for individual patients (MDC(95)). Anchor-based and distribution-based approaches were adopted to triangulate the ranges of minimal CIDs. The percentage of patients exceeding MDC(95) and minimal CIDs were also calculated.

RESULTS

The MDC(95) of the strength, activities of daily living/instrumental activities of daily living, mobility, and hand function subscales were 24.0, 17.3, 15.1, and 25.9, respectively. The respective minimal CIDs for these 4 subscales were 9.2, 5.9, 4.5, and 17.8 points, respectively, and the MDC(95) and CID proportions were 14% to 43%, 16% to 49%, 10% to 50%, and 23% to 64%, respectively.

CONCLUSIONS

The change score of an individual patient has to reach 24.0, 17.3, 15.1, and 25.9 on the 4 subscales to indicate a true change. The mean change scores of a stroke group on the 4 subscales should reach 9.2, 5.9, 4.5, and 17.8 points to be regarded as clinically important changes. Future research with larger sample sizes is warranted to validate these estimates.

Plasma disc decompression for contained cervical disc herniation: a randomized, controlled trial

Prospective case series studies have shown that plasma disc decompression (PDD) using the COBLATION SpineWand device (ArthroCare Corporation, Austin, TX) is effective for decompressing the disc nucleus in symptomatic contained cervical disc herniations. This prospective, randomized controlled clinical trial was conducted to evaluate the clinical outcomes of percutaneous PDD as compared to conservative care (CC) through 1 year. Patients (n = 115) had neck/arm pain >50 on the visual analog scale (VAS) pain scale and had failed at least 30 days of failed CC. Patients were randomly assigned to receive either PDD (n = 62) or CC (n = 58). Clinical outcome was determined by VAS pain score, neck disability index (NDI) score, and SF-36 health survey, collected at 6 weeks, 3 months, 6 months, and 1 year. The PDD group had significantly lower VAS pain scores at all follow-up time points (PDD vs. CC: 6 weeks, -46.87 +/- 2.71 vs. -15.26 +/- 1.97; 3 months, -53.16 +/- 2.74 vs. -30.45 +/- 2.59; 6 months, -56.22 +/- 2.63 vs. -40.26 +/- 2.56; 1 year, -65.73 +/- 2.24 vs. -36.45 +/- 2.86; GEE, P < 0.0001). PDD patients also had significant NDI score improvement over baseline when compared to CC patients at the 6 weeks (PDD vs. CC: -9.15 +/- 1.06 vs. -4.61 +/- 0.53, P < 0.0001) and 1 year (PDD vs. CC: -16.70 +/- 0.29 vs. -12.40 +/- 1.26, P = 0.005) follow-ups. PDD patients showed statistically significant improvement over baseline in SF-36 physical component summary scores when compared to CC patients at 6 weeks and 1 year (PDD vs. CC: 8.86 + 8.04 vs. 4.24 +/- 3.79, P = 0.0004; 17.64 +/- 10.37 vs. 10.50 +/- 10.6, P = 0.0003, respectively). In patients who had neck/arm pain due to a contained cervical disc herniation, PDD was associated with significantly better clinical outcomes than a CC regimen. At 1 year, CC patients appeared to suffer a "relapse, showing signs of decline in most measurements, whereas PDD patients showed continued stable improvement.

Dynamics of improvement following total lumbar disc replacement: is the outcome predictable?

STUDY DESIGN

Prospective clinical study of total lumbar disc replacement (TDR) with ProDisc II (Synthes, Paoli, PA).

OBJECTIVES

To examine whether baseline variables VAS (Visual Analogue Scale) and ODI (Oswestry Disability Index) correspond with late and final postoperative outcome parameters and to identify early predictors of late outcome following total lumbar disc replacement (TDR).

SUMMARY OF BACKGROUND DATA

Previously published TDR studies reported on the pooled data averages collected from various cohort sizes. The individual patient's prognosis as well as prognostic factors of postoperative improvement remain unestablished.

METHODS

Data were accumulated prospectively and included VAS and ODI scores. The subjective outcome evaluation was based on a 3-scale grading system ("highly satisfied," "satisfied," "not satisfied"). An analysis was performed to ascertain whether the late and final outcome following TDR can be predicted based on preoperative and early postoperative data from the 3 and 6 month follow-up (FU).

RESULTS

The overall results from 161 patients with an average FU of 4 years (mean: 45.5 months, range: 24.1-94.4 months) revealed a significant and maintained improvement of VAS and ODI scores (P < 0.0001). The most pronounced changes occurred within the early postoperative period (P < 0.0001) with no significant changes thereafter (P > 0.05).Baseline ODI levels were significantly correlated with VAS/ODI scores and patient satisfaction rates at the final FU (P < 0.0001).After surgery, early and late ODI levels were highly significantly correlated with each other (r = 0.84, P < 0.0001). Similar associations were observed between early and late VAS scores and patient satisfaction rates (P < 0.006).The individual patient's subjective outcome evaluation revealed stable postoperative results. An improvement or a deterioration by 2 classes on a 3-scale grading system was only observed in 3.1% (n = 5/161) of all cases overall. Patients with an early "highly satisfactory" result (n = 83) maintained either a satisfactory (15.7%, n = 13/83) or a highly satisfactory outcome (79.5%, n = 66/83) in 95.2% of all cases (n = 79/83).Conversely, the probability that patients with an "unsatisfactory" outcome would still achieve a "highly satisfactory" result after the early postoperative period was 5.0%.

CONCLUSION

Baseline ODI and early postoperative outcome parameters (< or =6 months) revealed significant and strong associations with the final results following TDR. While the vast majority of patients with an early highly satisfactory outcome maintained satisfactory results at later FU stages, any significant improvement considered as "highly satisfied" is unlikely in a group of patients which reported early unsatisfactory results. In summary, any clinically relevant changes are unlikely to occur after the early postoperative period.The current findings offer a foundation for weighing both the patients and the spine surgeons expectations against possible realistic achievements. Although the data show that the midterm outcome at a FU of 4 years (mean: 45.5 months, range: 24.1-94.4 months) is predictable following TDR, the long-term results of lumbar disc replacements still need to be established.

The Minimally Important Difference for Patient Reported Outcomes in Systemic Lupus Erythematosus Including the HAQ-DI, Pain, Fatigue, and SF-36

Objective.

We studied patients with systemic lupus erythematosus (SLE) in 1 clinical practice, and patients enrolled in the 1000 Canadian Faces of Lupus database, to determine the minimally important difference (MID) for pain, fatigue, sleep, Health Assessment Questionnaire-Disability Index (HAQ-DI), and Medical Outcomes Study Short Form-36 (SF-36) Physical Component Score (PCS) and SF-36 Mental Component Score (MCS) using a patient-reported overall health status anchor.

Methods.

Patients with SLE who had 2 consecutive clinic visits and completed a HAQ-DI and a pain, fatigue, and sleep visual analog scale (VAS) (0–100), and an overall health status question: “How would you describe your overall status since your last visit?”: much better, better, the same, worse, or much worse were included. Those who self-rated as better or worse were considered the “minimally changed” subgroups. Patients with 2 consecutive annual visits in the 1000 Canadian Faces of Lupus database who completed the SF-36 and health transition question were eligible.

Results.

There were 202 patients in London, Ontario (94% women, mean age 50 yrs, mean disease duration 10 yrs). MID for better and worse on a VAS (0–100) were: pain (−15.8, 8.5), fatigue (−13.9, 9.1), and sleep problems (−8.6, 7.6). The MID for HAQ-DI (scale 0 to 3) was −0.08 (better) and 0.14 (worse). The MID for SF-36 was 2.1 (better) and −2.2 (worse) for the PCS and 2.4 (better) and −1.2 (worse) in the MCS.

Conclusion.

The MID in patients with SLE may be different bidirectionally depending on the measured outcome. The mean change observed for those reporting better than worse outcome in pain and fatigue was greater for better versus worst, in contrast to the HAQ, where the mean change was greater for worsening.

What is an acceptable outcome of treatment before it begins? Methodological considerations and implications for patients with chronic low back pain

Understanding changes in patient-reported outcomes is indispensable for interpretation of results from clinical studies. As a consequence the term "minimal clinically important difference" (MCID) was coined in the late 1980s to ease classification of patients into improved, not changed or deteriorated. Several methodological categories have been developed determining the MCID, however, all are subject to weaknesses or biases reducing the validity of the reported MCID. The objective of this study was to determine the reproducibility and validity of a novel method for estimating low back pain (LBP) patients' view of an acceptable change (MCID(pre)) before treatment begins. One-hundred and forty-seven patients with chronic LBP were recruited from an out-patient hospital back pain unit and followed over an 8-week period. Original and modified versions of the Oswestry disability index (ODI), Bournemouth questionnaire (BQ) and numeric pain rating scale (NRS(pain)) were filled in at baseline. The modified questionnaires determined what the patient considered an acceptable post-treatment outcome which allowed us to calculate the MCID(pre). Concurrent comparisons between the MCID(pre), instrument measurement error and a retrospective approach of establishing the minimal clinically important difference (MCID(post)) were made. The results showed the prospective acceptable outcome method scores to have acceptable reproducibility outside measurement error. MCID(pre) was 4.5 larger for the ODI and 1.5 times larger for BQ and NRS(pain) compared to the MCID(post). Furthermore, MCID(pre) and patients post-treatment acceptable change was almost equal for the NRS(pain) but not for the ODI and BQ. In conclusion, chronic LBP patients have a reasonably realistic idea of an acceptable change in pain, but probably an overly optimistic view of changes in functional and psychological/affective domains before treatment begins.

Minimal important differences of the SRS-22 Patient Questionnaire following surgical treatment of idiopathic scoliosis

The responsiveness of an instrument measuring health-related quality of life is an important indication of its construct validity. The SRS-22 Patient Questionnaire has become the most widely used patient-reported outcome instrument in the clinical evaluation of patients with idiopathic scoliosis. The responsiveness of the SRS-22 following surgical treatment in patients with idiopathic scoliosis has not been fully assessed. The aim of this study is to evaluate this factor by calculating the minimal important differences (MIDs) of the SRS-22 Questionnaire. The study included 91 patients with idiopathic scoliosis (77 females and 14 males), who underwent surgical treatment; mean age at the time of surgery was 18.1 years. Patients completed the SRS-22 questionnaire before surgery and at a follow-up visit (mean follow-up, 45.6 months). At follow-up, patients rated their overall situation as related to before surgery with a four-point Likert scale: 1-Worse, 2-Same, 3-Better, 4-Much Better. This evaluation represented the global perceived effect (GPE) and served as the anchor criterion for calculating the MID. MIDs were calculated using two approaches. The anchor-based MID (MID-A) was defined as the mean preoperative/follow-up difference in SRS-22 scores in the group of patients who stated they were much better than before surgery (GPE = 4). Using the same anchor criterion, the optimal cut-off value able to identify patients that had clearly improved was determined on a receiver operating characteristic (ROC) curve. In addition, the distribution-based MID (MID-D) was calculated by the standard error of measurement method. The MID-As found for the different subscales and the sum score were: pain 0.6, function 0.3, image 1.3, mental health 0.3, average sum score 0.6, and raw sum score 13.1. The cut-off values on the ROC curve were: pain 0.2, function 0.0, image 1.6, mental health 0.4, average sum score 0.4, and raw sum score 10. The MID-Ds were: pain 0.6, function 0.8, image 0.5, mental health 0.4, average sum score 0.5, and raw sum score 6.8. As was expected, the MID values differed according to the calculation method used. In light of the fact that the MID-As for the function and mental health subscales are below the measurement error of the instrument, it seems preferable to use the MID-D values for determining subscale changes. If the purpose is to analyze sum score changes (either the raw or average values), the MID-A is preferable because it includes the patient's evaluation of the results of surgery.