Minimum clinically important difference in lumbar spine surgery patients: a choice of methods using the Oswestry Disability Index, Medical Outcomes Study questionnaire Short Form 36, and pain scales

BACKGROUND CONTEXT: The impact of lumbar spinal surgery is commonly evaluated with three patient-reported outcome measures: Oswestry Disability Index (ODI), the physical component summary (PCS) of the Short Form of the Medical Outcomes Study (SF-36), and pain scales. A minimum clinically important difference (MCID) is a threshold used to measure the effect of clinical treatments. Variable threshold values have been proposed as MCID for those instruments despite a lack of agreement on the optimal MCID calculation method. PURPOSE: This study has three purposes. First, to illustrate the range of values obtained by common anchor-based and distribution-based methods to calculate MCID. Second, to determine a statistically sound and clinically meaningful MCID for ODI, PCS, back pain scale, and leg pain scale in lumbar spine surgery patients. Third, to compare the discriminative ability of two anchors: a global health assessment and a rating of satisfaction with the results of the surgery. STUDY DESIGN: This study is a review of prospectively collected patient-reported outcomes data. PATIENT SAMPLE: A total of 454 patients from a large database of surgeries performed by the Lumbar Spine Study Group with a 1-year follow-up on either ODI or PCS were included in the study. OUTCOME MEASURES: Preoperative and 1-year postoperative scores for ODI, PCS, back pain scale, leg pain scale, health transition item (HTI) of the SF-36, and Satisfaction with Results scales. METHODS: ODI, SF-36, and pain scales were administered before and 1 year after spinal surgery. Several candidate MCID calculation methods were applied to the data and the resulting values were compared. The HTI of the SF-36 was used as the anchor and compared with a second anchor (Satisfaction with Results scale). RESULTS: Potential MCID calculations yielded a range of values: fivefold for ODI, PCS, and leg pain, 10-fold for back pain. Threshold values obtained with the two anchors were very similar. CONCLUSIONS: The minimum detectable change (MDC) appears as a statistically and clinically appropriate MCID value. MCID values in this sample were 12.8 points for ODI, 4.9 points for PCS, 1.2 points for back pain, and 1.6 points for leg pain.     

Usefulness of minimum clinically important difference for assessing patients with subaxial degenerative cervical spine disease: statistical versus substantial clinical benefit

Background

The measurement of the therapeutic outcome of cervical spine surgeries commonly relies on four main patient reported outcomes (PROs): Neck Disability Index (NDI), Visual Analog Scale (VAS) for pain, and Short Form-36 (SF-36) Physical (PCS) and Mental (MCS) Component Summary. However, the clinical impact of such scores and how they could effectively measure therapeutic efficacy remains unclear. In this context, the concept of minimum clinically important difference (MCID) is developing into the standard by which to evaluate treatments, patient satisfaction and cost-effectiveness.

Methods

Eighty-eight consecutive patients undergoing surgery for subaxial degenerative cervical spine disease were selected from a prospective blinded database. PROs (NDI, PCS, MCS and VAS) were collected preoperatively, and together with blinded Surgeon Ratings (SR) at 3 months and 6 months post-surgery. Four anchor-based approaches were used to calculate different MCIDs. Three anchors (VAS, HTI (Health Transition Item of the SF-36) and SR) were used to evaluate surgery outcome. The best clinically and statistically relevant MCID was chosen.

Results

On average, all patients presented with a statistically significant improvement (p?<?0.001) postoperatively for NDI (27.42 to 19.42), PCS (33.02 to 42.03), MCS (44 to 50.74) and VAS (2.85 to 1.93). The four MCID anchor-based approaches yielded a range of values for each PRO: 2.23–16.59 for PCS, 0.11–16.27 for MCS and 2.72–12.08 for NDI. When compared to the VAS and HTI anchors, the area under the ROC curve was greater for SR. This finding suggests that SR may be a more reliable anchor for MCID calculation.

Conclusion

The MDC (minimum detectable change) approach together with the SR anchor appears to be the most appropriate MCID method. It offers the greatest area under the ROC curve (threshold above the 95 % CI), and the choice of the anchor did not significantly affect this result. MCID values for this dataset were 5.6 for PCS, 5.12 for MCS and 2.41 for NDI.     

Preoperative Zung depression scale predicts patient satisfaction independent of the extent of improvement after revision lumbar surgery

Background contextPatient satisfaction ratings are increasingly being used in health care as a proxy for quality and are becoming the focal point for several quality improvement initiatives. Affective disorders, such as depression, have been shown to influence patient-reported outcomes and self-interpretation of health status. We hypothesize that patient psychiatric profiles influence reported satisfaction with care, independent of surgical effectiveness.PurposeTo assess the predictive value of preoperative depression on patient satisfaction after revision surgery for same-level recurrent stenosis.Study designRetrospective cohort study.Patient sampleFifty-three patients undergoing a revision surgery for symptomatic same-level recurrent stenosis.Outcome measuresPatient-reported outcome measures were assessed using an outcomes questionnaire that included questions on health state values (EuroQol-5D [EQ-5D]), disability (Oswestry Disability Index [ODI]), pain (visual analog scale [VAS]), depression (Zung self-rating depression scale), and Short Form 12 (SF-12) physical and mental component scores (PCS and MCS). Patient satisfaction was dichotomized as either “YES” or “NO” on whether they were satisfied with their surgical outcome 2 years after the surgery.MethodsA total of fifty-three patients undergoing revision neural decompression and instrumented fusion for same-level recurrent stenosis-associated back and leg pain were included in this study. Preoperative Zung self-rating depression score (ZDS), education status, comorbidities, and postoperative satisfaction with surgical care and outcome was assessed for all patients. Baseline and 2-year VAS for leg pain (VAS-LP), VAS for low back pain (VAS-BP), ODI, SF-12 PCS and MCS, and health-state utility (EQ-5D) were assessed. Factors associated with patient satisfaction after surgery were assessed via multivariate logistic regression analysis.ResultsTwo years after surgery, a significant improvement was reported in all outcome measures: VAS-BP (5±2.94 vs. 9.28±1, p<.001), VAS-LP (3.43±2.95 vs. 9.5±0.93, p<.001), ODI (21.75±12.07 vs. 36.01±6, p<.001), SF-12 PCS (32.30±11.01 vs. 25.13±5.84, p<.001), SF-12 MCS (47.48±10.96 vs. 34.91±12.77, p<.001), EQ-5D (0.60±0.31 vs. 0.18±0.22, p<.001), and ZDS (37.52±11.98 vs. 49.90±10.88, p<.001). Independent of postoperative improvement in pain and disability (surgical effectiveness), increasing preoperative Zung depression score was significantly associated with patient dissatisfaction 2 years after revision lumbar surgery (Odds ratio=0.67 [confidence interval: 0.38, 0.87], p<.001).ConclusionsOur study suggests that independent of the surgical effectiveness, the extent of preoperative depression influences the reported patient satisfaction after revision lumbar surgery. Quality improvement initiatives using patient satisfaction as a proxy for quality should account for the patients' baseline depression as potential confounders.     

Minimal clinically important difference in patients who underwent decompression alone for lumbar degenerative disease

Background ContextThe minimal clinically important difference (MCID) represents the smallest change in an outcome measure recognized as clinically meaningful to a patient after receiving a clinical intervention. Most studies that discussed the MCIDs for lumbar spinal stenosis (LSS) included mixed pathologies or procedures despite that the MCID value should be different depending on the intervention. Moreover, despite the efficacy of adopting percentage-change improvement for the MCID threshold, there are limited reports and discussions in the field of lumbar surgery.PurposeThe aim of the present study was to elucidate the MCIDs for the Oswestry Disability Index (ODI), EuroQOL 5-dimension 3-level (EQ-5D-3L), physical component summary (PCS) of the Short Form of the Medical Outcomes Study, and Numeric Rating Scale (NRS) in patients with degenerative LSS treated with decompression surgery without fusion.Study Design/SettingA multicenter retrospective cohort study was performed.Patient SampleA total of 422 patients who underwent decompression surgery for LSS and answered a complete set of questionnaires were included in the study. Patients who underwent endoscopic or revision surgery were excluded.Outcome MeasuresPreoperative and 1-year postoperative scores of each health-related quality of life questionnaires (HRQOLs) and patient satisfaction questionnaire responseMethodsThe patient satisfaction question was used as an anchor, and the cutoff values were estimated based on absolute point improvement from baseline using a receiver-operating characteristic (ROC) curve analysis and the “mean change” method for MCIDs. The MCID values for percentage-change in HRQOLs were also calculated using ROC curve analysis. The three cutoff values for each HRQOL were validated using the Youden index for determining the most robust MCIDs.ResultsOf the patients, 356 (84.4%) were at least “somewhat satisfied” with the treatment results. The two cutoff values of absolute point-change in each HRQOL, which were estimated by two different anchor-based methods, were similar. The area under the curve of the ROC curve for percentage-change tended to be higher than that for absolute point-change. Moreover, the Youden index of the percentage-change in each HRQOL was higher than that of the absolute point-change calculated by either the “mean change” method or the ROC curve analysis. Based on these results, it was proposed that MCID was 42.4% for percentage-change in ODI, 22.0% for EQ-5D-3L, 13.7% for PCS, 25.0% for NRS (low back pain), 55.6% for NRS (leg pain), 22.2% for NRS (leg numbness).ConclusionsThe MCIDs of HRQOLs were calculated in patients with LSS treated with decompression surgery without concomitant fusion procedure. The MCID cutoffs based on percentage-change from baseline were more effective than those of absolute point-change.     

Testing minimal clinically important difference: consensus or conundrum?

Background ContextVarious 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.PurposeThe purpose was to test the validity of recently published guidelines regarding MCID using self-report back pain measures and objective socioeconomic outcomes.Study Design/SettingThis 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 SampleThe study consisted of consecutive cohort of patients (N=1,180) with CDOSDs completing a functional restoration program.Outcomes MeasuresSelf-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.MethodsPre- 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.ResultsThe 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.ConclusionsWhen 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.     

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 ContextThe 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).PurposeThis 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/SettingThe study setting is a longitudinal cohort in a multisurgeon spine specialty clinic.Patient sampleThe 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 MeasuresThe outcome measures of the study were NDI, SF-36, and numeric rating scales for arm and neck pain.MethodsThe 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.ResultsThe 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.ConclusionsPatients 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.     

Construct validity and responsiveness of commonly used patient reported outcome instruments in decompression for lumbar spinal stenosis

BackgroundValidity and responsiveness of Oswestry disability index (ODI), Roland Morris disability questionnaires (RMDQ), Short Form-12 Physical Component Score (SF-12 PCS) and Short Form-12 Mental Component Score (SF-12 MCS) in patients undergoing open decompression for lumbar canal stenosis has not been previously reported.MethodsOutcome assessment was prospectively evaluated using the ODI, RMDQ, SF-12 PCS and SF-12 MCS pre-intervention and at average follow-up of three months post-intervention. Pearson correlation coefficient was used to evaluate the association between change in values of ODI, RMDQ, SF-12 PCS and SF-12 MCS. Distribution based methods (Effect size [ES], standardised response mean [SRM]) and anchor based method (Area under the curve [AUC] of receiver operating curve [ROC]) were used to determine responsiveness. AUC value ≥ 0.70 is considered as adequate level of responsiveness and the outcome instrument with the largest AUC is considered to be the most responsive outcome instrument.ResultsThis study included 77 participants. Responsiveness was assessed at a mean follow-up of 12 weeks postoperatively. There was significant strong correlation between ODI and RMDQ (r = 0.65, p < 0.0001). The ES of ODI, RMDQ, SF-12 PCS and SF-12 MCS were 1.54, 1.48, 1.85 and 0.51 respectively. The SRM of RMDQ, ODI, SF-12 PCS and SF-12 MCS were 1.22, 1.17, 1.0 and 0.47 respectively. AUC of ODI, RMDQ, SF-12 PCS and SF-12 MCS were 0.83–0.88, 0.82 to 0.86, 0.78 to 0.81 and 0.69 to 0.70 respectively.ConclusionIt is recommended to use either ODI or RMDQ as region specific patient reported outcome instrument and SF-12 PCS as a health related quality of life outcome instrument to evaluate outcome after decompressive laminectomy for lumbar canal stenosis.     

Preoperative Zung Depression Scale predicts outcome after revision lumbar surgery for adjacent segment disease, recurrent stenosis, and pseudarthrosis

Background contextPersistent back pain and leg pain after index surgery is distressing to patients and spinal surgeons. Revision surgical treatment is technically challenging and has been reported to yield unpredictable outcomes. Recently, affective disorders, such as depression and anxiety, have been considered potential predictors of surgical outcomes across many disease states of chronic pain. There remains a paucity of studies assessing the predictive value of baseline depression on outcomes in the setting of revision spine surgery.PurposeTo assess the predictive value of preoperative depression on 2-year postoperative outcome after revision lumbar surgery for symptomatic pseudarthrosis, adjacent segment disease (ASD), and same-level recurrent stenosis.Study designRetrospective cohort study.Patient sampleOne hundred fifty patients undergoing revision surgery for symptomatic ASD, pseudarthrosis, and same-level recurrent stenosis.Outcome measuresPatient-reported outcome measures were assessed using an outcomes questionnaire that included questions on health-state values (EQ-5D), disability (Oswestry Disability Index [ODI]), pain (visual analog scale), depression (Zung Self-Rating Depression Scale), and 12-Item Short Form Health Survey physical and mental component scores.MethodsOne hundred fifty patients undergoing revision neural decompression and instrumented fusion for ASD (n=50), pseudarthrosis (n=47), or same-level recurrent stenosis (n=53) were included in this study. Preoperative Zung Self-Reported Depression Scale score was assessed for all patients. Preoperative and 2-year postoperative visual analog scale for back pain and leg pain scores and ODI were assessed. The association between preoperative Zung Depression Scale score and 2-year improvement in disability was assessed via multivariate regression analysis.ResultsCompared to preoperative status, VAS-BP was significantly improved 2 years after surgery for ASD (8.72±1.85 vs. 3.92±2.84, p=.001), pseudoarthrosis (7.31±0.81 vs. 5.06±2.64, p=.001), and same-level recurrent stenosis (9.28±1.00 vs. 5.00±2.94, p=.001). Two-year ODI was also significantly improved after surgery for ASD (28.72±9.64 vs. 18.48±11.31, p=.001), pseudoarthrosis (29.74±5.35 vs. 25.42±6.00, p=.001), and same-level recurrent stenosis (36.01±6.00 vs. 21.75±12.07, p=.001). Independent of age, BMI, symptom duration, smoking, comorbidities, and level of preoperative pain and disability, increasing preoperative Zung depression score was significantly associated with less 2-year improvement in disability (ODI) after revision surgery for ASD, pseudoarthrosis, and recurrent stenosis.ConclusionsOur study suggests that the extent of preoperative depression is an independent predictor of functional outcome after revision lumbar surgery for ASD, pseudoarthrosis, and recurrent stenosis. Future comparative effectiveness studies assessing outcomes after revision lumbar surgery should account for depression as a potential confounder. The Zung depression questionnaire may help risk stratify patients presenting for revision lumbar surgery.     

Workers compensation patients experiencing depression report meaningful improvement in mental health scores after anterior cervical discectomy and fusion

BackgroundMental health has been demonstrated to affect postoperative outcomes. No prior literature has reported the relationship between preoperative mental health on outcomes following anterior cervical discectomy and fusion (ACDF) in the Workers Compensation (WC) population.MethodsWC claimants who underwent primary ACDF were identified from a single-surgeon retrospective database. Patients were separated by SF-12 MCS score into Depressed (<45.6) or Not Depressed (ND) (≥45.6) cohorts. Patient-reported Outcome Measurement Information System Physical Function (PROMIS PF), SF-12 Physical Component Score (SF-12 PCS), SF-12 MCS, visual analog scale (VAS) neck/arm pain, and Neck Disability Index (NDI) were collected and compared within and between groups. Minimum clinically important difference (MCID) achievement rates were compared between groups.ResultsDepressed patients had greater length of stay (p = 0.007) and postoperative narcotic consumption (p = 0.026). Depressed patients improved at 12-week to 2-year PROMIS PF, 6-month SF-12 PCS, 6-week to 6-month SF-12 MCS, 6-week to 6-month and 2-year VAS neck, all VAS arm, and 6-month NDI (p ≤ 0.045, all). ND patients improved at 12-week to 1-year PROMIS PF, 6-month to 2-year SF-12 PCS, 12-week to 1-year VAS neck, 6-week to 1-year VAS arm, and 12-week to 1-year NDI (p ≤ 0.044, all). Between groups, ND patients reported superior PROMIS PF, SF-12 MCS, VAS neck, VAS arm, and NDI scores at two or more periods (p ≤ 0.045, all). MCID achievement rate regarding SF-12 MCS was greater in the Depressed cohort at all postoperative points up to 1 year (p ≤ 0.020, all).ConclusionDepressed patients tended to have a greater length of stay and postoperative narcotic consumption immediately after surgery. Not depressed patients reported more favorable physical and mental function, pain, and disability scores preoperatively and postoperatively. Depressed patients reported greater MCID achievement in mental function following surgery. Depressed patients with WC have a greater likelihood of reporting tangible improvement in mental health scores following ACDF.     

Association between muscle health and patient-reported outcomes after lumbar microdiscectomy: early results

BACKGROUND CONTEXTPoor muscle health has been implicated as a source of back pain among patients with lumbar spine pathology. Recently, a novel magnetic resonance imaging (MRI)-based lumbar muscle health grade was shown to correlate with health-related quality of life scores. However, the impact of muscle health on postoperative functional outcomes following spine surgery remains to be investigated.PURPOSETo determine whether muscle health grade measured by preoperative psoas and paralumbar muscle cross-sectional areas impact the achievement of minimal clinically important difference (MCID) following lumbar microdiscectomy.STUDY DESIGN/SETTINGRetrospective cohort study.PATIENT SAMPLEConsecutive patients who underwent 1-level lumbar microdiscectomy in a single institution between 2017 and 2021.OUTCOME MEASURESRate of MCID achievement, time to MCID achievement, PROMs including Oswestry Disability Index (ODI), visual analog scale for back pain (VAS back), VAS leg, Short Form 12 Physical Component Summary (SF-12 PCS), SF-12 Mental Component Summary (SF-12 MCS), and Patient Reported Outcomes Measurement Information System Physical Function (PROMIS PF).METHODSTwo previously validated methods for muscle health grading were applied. Axial T2 MRI were analyzed for muscle measurements. The psoas-based method utilized the normalized total psoas area (NTPA), which is the psoas cross-sectional area divided by the square of patient height (mm²/m²). Patients were divided into low and high NTPA groups based on sex-specific lowest quartile NTPA thresholds. The paralumbar-based method incorporated the paralumbar cross-sectional area normalized by body mass index (PL-CSA/BMI) and Goutallier classification. Score of 1 was added for either PL-CSA/BMI >130 or Goutallier class of ≤2. “Good” muscle health was defined as score of 2, and “poor” muscle health was defined as score of 0 to 1. Prospectively collected PROMs were analyzed at 2-week, 6-week, 3-month, 6-month, 1-year, and 2-year postoperative timepoints. The rate of and time to MCID achievement were compared among the cohorts. Bivariate analyses were performed to assess for correlations between psoas/paralumbar cross-sectional areas and change in PROM scores from baseline.RESULTSThe total cohort included 163 patients with minimum follow-up of 6 months and mean follow-up of 16.5 months. 40 patients (24.5%) were categorized into the low NTPA group, and 55 patients (33.7%) were categorized into the poor paralumbar muscle group. Low NTPA was associated with older age, lower BMI, and greater frequencies of Charlson Comorbidity Index (CCI) ≥1. Poor paralumbar muscle health was associated with older age, female sex, higher BMI, and CCI ≥1. There were no differences in rates of MCID achievement for any PROMs between low versus high NTPA groups or between poor versus good paralumbar groups. Low NTPA was associated with longer time to MCID achievement for ODI, VAS back, VAS leg, and SF-12 MCS. Poor paralumbar muscle health was associated with longer time to MCID achievement for VAS back, VAS leg, and SF-12 PCS. NTPA negatively correlated with change in VAS back (6-week, 12-week) and VAS leg (6-month). PL-CSA/BMI positively correlated with change in PROMIS-PF at 3 months follow-up.CONCLUSIONSAmong patients undergoing lumbar microdiscectomy, patients with worse muscle health grades achieved MCID at similar rates but required longer time to achieve MCID. Lower NTPA was weakly correlated with larger improvements in pain scores. PL-CSA/BMI positively correlated with change in PROMIS-PF. Our findings suggest that with regards to functional outcomes, patients with worse muscle health may take longer to recuperate postoperatively compared to those with better muscle health.     

Minimum clinically important difference of the health-related quality of life scales in adult spinal deformity calculated by latent class analysis: is it appropriate to use the same values for surgical and nonsurgical patients?

BACKGROUND CONTEXT

Health-related quality of life (HRQOL) parameters have been shown to be reliable and valid in patients with adult spinal deformity (ASD). Minimum clinically important difference (MCID) has become increasingly important to clinicians in evaluating patients with a threshold of improvement that is clinically relevant.

Impact of early unanticipated revision surgery on health-related quality of life after adult spinal deformity surgery

Background Context

Revision surgery represents a major event for patients undergoing adult spinal deformity (ASD) surgery. Previous reports suggest that ASD surgery has minimal or no impact on health-related-quality of life (HRQOL) outcomes.

Validating the VR-12 Physical Function Instrument After Anterior Cervical Discectomy and Fusion with SF-12, PROMIS,and NDI

Background

Development and validation of Veterans RAND 12-item (VR-12) physical component survey (PCS) has been established among civilian and veteran populations but it has not been examined among anterior cervical discectomy and fusion (ACDF) patients.

Purposes/Questions

We sought to validate legacy patient-reported outcome measures (PROMs) with VR-12 PCS among patients undergoing ACDF procedures.

Methods

A prospectively collected surgical registry was retrospectively evaluated for elective single or multi-level ACDFs performed for degenerative spinal pathologies from January 2014 to August 2019. Exclusion criteria included missing pre-operative surveys and surgery for trauma, metastasis, or infection. Demographic variables, baseline pathologies, and peri-operative variables were collected. A paired t test evaluated the change from the pre-operative score to each post-operative timepoint for VR-12 PCS, the 12-item Short-Form Survey (SF-12) PCS, Patient-Reported Outcomes Measurement Information System physical function (PROMIS-PF), and Neck Disability Index (NDI). Minimal clinically important difference (MCID) achievement was calculated at each timepoint. Correlation was evaluated with a Pearson’s correlation coefficient and time-independent partial correlation.

Results

Of the 202 patients who underwent ACDF, 41.1% were female and the average age was 49.5 years. All PROMs had statistically significantly increased from baseline when compared with post-operative timepoints (12 weeks, 6 months, 1 year, and 2 years). MCID achievement rates increased through 2 years. All timepoints revealed strong VR-12 PCS correlations with SF-12 PCS, PROMIS-PF, and NDI scores.

Conclusion

VR-12 PCS was strongly correlated with the well-validated SF-12 PCS and NDI metrics as well as with the more recent PROMIS-PF. All PROMs demonstrated statistically significant improvement in patients post-operatively. VR-12 PCS is a valid measure of physical function among patients undergoing ACDF.

     

The effect of smoking on achieving meaningful clinical outcomes one year after lumbar tubular microdecompression: a matched-pair cohort analysis

BACKGROUND CONTEXTThere has been a shift in the spine literature in reporting meaningful outcomes, including meaningful clinically important difference (MCID), after surgery. The evidence on the effect of tobacco smoking at the time of lumbar tubular microdecompression (LTMD) on meaningful outcomes is limited.PURPOSETo compare differences in 1-year functional outcomes and rates of achieving MCID between current smokers and non-smokers who underwent LTMD for lumbar spinal stenosis (LSS).STUDY DESIGNA nested case control study to compare the difference in patient reported outcomes (PROs) between smokers and non-smokers 1-year after undergoing LTMD.PATIENT SAMPLEThis study included patients that underwent single level LTMD by a single surgeon between January 2014 through August 2019.OUTCOME MEASURESPreoperative and postoperative PROs were recorded using the questionnaires EQ-5D, Oswestry Disability Index (ODI), and the visual analog scale (VAS) for back pain and leg pain. The MCID was also used.METHODSCurrent tobacco smokers at the time of surgery were matched 1:2 to non-smokers by age (+/- 1year). Preoperative and postoperative functional scores were compared between the two groups using independent t-tests. Additionally, thresholds for achieving MCID were calculated for each individual functional score, and were compared using Fisher's exact test.RESULTSOf the 183 patients with 1-year follow-up who met inclusion criteria, 35 patients were identified as smokers and were matched to 70 non-smokers. No statistical differences were identified between age, BMI, or gender. Comparison of preoperative PROs showed no statistically significant differences between smokers and non-smokers (p>0.05 for all), while smokers had statistically lower EQ-5D (p<0.001) and higher ODI (p=0.05), VAS back (p=0.033), and VAS leg (p=0.03) score averages at a minimum of one year follow-up. Evaluation of meaningful outcomes demonstrated non-smokers had higher rates of achieving MCID on at least 1 threshold score as compared to smokers (98.5% vs. 91.1%; p=0.043).CONCLUSIONSCurrent smokers at the time of surgery have inferior postoperative EQ-5D scores, increased pain and disability, and lower odds of achieving the MCID at 1-year after undergoing LTMD when compared to patients without any smoking history.     

Assessment of spine surgery outcomes: inconsistency of change amongst outcome measurements

Background ContextOutcomes of spinal treatments are evaluated by clinical relevance: the proportion of patients who reach a minimum clinically important outcome change. Outcomes are evaluated through multiple measurements, and the inconsistency of outcome change across measurements is not known.PurposeThe primary purpose of this study was to illustrate outcome inconsistencies after spinal surgery. Secondary goals of this study were to develop an index of overall change that incorporates outcome inconsistencies, to relate the index of overall change to patients' global assessment and satisfaction with treatment, to relate the index of global change to an intuitively understandable outcome: the level of tolerable pain.Study DesignThis study is a review of prospectively collected patient-reported outcomes data.Patient SampleFour hundred sixty patients from a large multicenter database were chosen. Those patients were included in the sample because they had undergone lumbar surgery and had baseline and 1-year follow-up scores. Baseline and 1-year follow-up scores for Oswestry Disability Index (ODI), physical component summary (PCS) of the Medical Outcome Study Short Form-36 (SF-36), numerical back and leg pain scales, and 1-year scores for satisfaction with results were included in the study.Outcome MeasuresThe outcome measures of the study were preoperative and 1-year postoperative scores for ODI, PCS, back pain scale, leg pain scale, health transition item of the SF-36, and satisfaction with results scales.MethodsOswestry Disability Index, SF-36, and pain scales were administered before and 1 year after spinal surgery. Satisfaction with results questionnaires were administered 1 year after surgery. The following threshold values were previously established and were used to evaluate outcome changes: minimum clinically important difference (MCID), substantial clinical benefit (SCB), and standard error of the mean. The following proportions of patients were determined according to outcome changes: “deteriorated,” “no change,” “below MCID,” “above MCID,” and “above SCB.” The consistency of outcome change was determined amongst the four outcome measures. An index of overall change was developed and related to patients' answers to the health transition item of the SF-36 and to the satisfaction with results scale. The overall change index was also compared with the tolerable pain level.ResultsOnly 40.5% of patients report consistent outcome changes on all four measures. The overall change index was significantly correlated to the global change and satisfaction scale (ρ=.67, p less than .001). The overall change index was clearly associated with the tolerable pain level.ConclusionsEfforts should be made to take into account the inconsistency of outcomes and to make clinical relevance more readily understandable by patients and clinicians.     

A Weighted Scoring System Based on Preoperative and Long-Term Patient-Reported Outcome Measures to Guide Timing of Knee Arthroplasty

BackgroundThere is currently no existing consensus regarding timing of knee arthroplasty. This study aimed to develop a weighted scoring system from patient-reported outcome measures (PROMs) to guide timing of knee arthroplasty based on preoperative severity and long-term effectiveness.MethodsProspectively collected data of 766 total knee arthroplasties (TKAs) and 382 unicompartmental knee arthroplasties (UKAs) at a single institution were analyzed. PROMs were assessed preoperatively and at 10 years using the Knee Society Score (KSS), Oxford Knee Score (OKS), and Short Form-36 physical component score (SF-36 PCS). Receiver operating characteristic analysis identified thresholds where preoperative PROMs predicted 10-year clinically meaningful improvements (minimal clinically important difference [MCID]). Threshold weights were assigned to PROMs based on their ability to predict MCID in isolation or in combination.ResultsPoorer baseline PROMs predicted 10-year MCID attainments. The threshold of 49.5 points for the KSS, 30.5 points for the OKS, and 40.7 points for the SF-36 PCS and 55.5 points for the KSS, 33.5 points for the OKS, and 40.5 points for the SF-36 PCS was weighted 1 point for predicting MCID in 1 PROM for TKA and UKA, respectively. The threshold of 33.4 and 33.9 points for the SF-36 PCS was weighted 2 points for predicting MCID in 2 PROMs, whereas 29.3 and 31.3 points for the SF-36 PCS were weighted 3 points for predicting MCID in 3 PROMs for TKA and UKA, respectively. The sum of weighted components from 0 (lowest) to 5 (highest) represented likelihood for long-term benefits at 10 years.ConclusionThis scoring system is a useful clinical adjunct for deciding timing of knee arthroplasty and prioritizing patients in institutions with long waitlists.Level of EvidenceII.     

Multimodal analgesic protocol for cervical disc replacement in the ambulatory setting: Clinical case series

BackgroundEffective pain management is paramount for outpatient surgical success. This study aims to report a case series of patients undergoing cervical disc replacement (CDR) in an ambulatory surgery center (ASC) with the use of an enhanced multimodal analgesic (MMA) protocol.MethodsPrimary, single-/2-level CDR procedures at an ASC with an enhanced MMA protocol were included. ASC patients were discharged day of surgery. Patient-reported outcome measures (PROMs) were administered at preoperative/6-week/12-week/6-month/1-year/2-year timepoints and included Visual Analogue Scale (VAS) neck, VAS arm, Neck Disability Index (NDI), Patient-Reported Outcomes Measurement Information System-Physical Function (PROMIS-PF), and 12-Item Short-Form Physical and Mental Composite Score (SF-12 PCS/SF-12 MCS). A t-test assessed postoperative PROM improvement from baseline. MCID achievement was determined by comparing ΔPROM scores to previously established thresholds.Results106 patients were included, 76 single-level and 30 2-level. Most single-levels occurred at C5–C6, most 2-levels at C5–C7. One 2-level patient developed a hematoma 5 days postoperatively and underwent revision for evacuation. Five patients reported postoperative dysphagia; all were quickly resolved. One patient had an episode of seizure secondary to serotonin syndrome from concealed drug use. Patient was reintubated, transferred, and treated for serotonin syndrome. Two patients experienced postoperative nausea/vomiting. Cohort significantly improved from baseline for all PROMS at all timepoints except SF-12 MCS at 1-year/2-years and SF-12 PCS at 2 years (p < 0.047, all). Overall MCID achievement rates were: VAS arm (48.7%), VAS neck (69.1%), NDI (98.9%), SF-12 MCS (50.0%), SF-12 PCS (54.6%), and PROMIS-PF (73.4%).ConclusionOutpatient CDR, incorporating an enhanced MMA protocol, can be safely and effectively performed with proper patient selection and surgical technique. Patients saw timely discharge, well-controlled postoperative pain, and favorable long-term outcomes.     

Preoperative MRI predictors of health-related quality of life improvement after microscopic lumbar discectomy

BACKGROUNDLumbar herniated nucleus pulposus (HNP) is a common spinal pathology often treated by microscopic lumbar discectomy (MLD), though prior reports have not demonstrated which preoperative MRI factors may contribute to significant clinical improvement after MLD.PURPOSETo analyze the MRI characteristics in patients with HNP that predict meaningful clinical improvement in health-related quality of life scores (HRQoL) after MLD.STUDY DESIGN/SETTINGRetrospective clinical and radiological study of patients undergoing MLD for HNP at a single institution over a 2-year period.PATIENT SAMPLEEighty-eight patients receiving MLD treatment for HNP.OUTCOME MEASURESCephalocaudal Canal Migration; Canal & HNP Anterior-Posterior (AP) Lengths and Ratio; Canal & HNP Axial Areas and Ratio; Hemi-Canal & Hemi-HNP Axial Areas and Ratio; Disc appearance (black, gray, or mixed); Baseline (BL); and 3-month (3M) postoperative HRQoL scores.METHODSPatients >18 years old who received MLD for HNP with BL and 3M HRQoL scores of PROMIS (Physical Function, Pain Interference, and Pain Intensity), ODI, VAS Back, and VAS Leg scores were included. HNP and spinal canal measurements of cephalocaudal migration, AP length, area, hemi-area, and disc appearance were performed using T2 axial and sagittal MRI. HNP measurements were divided by corresponding canal measurements to calculate AP, Area, and Hemi-Area ratios. Using known minimal clinically important differences (MCID) for each ΔHRQoL score, patients were separated into two groups based on whether they reached MCID (MCID+) or did not reach MCID (MCID–). The MCID for PROMIS pain intensity was calculated using a decision tree. A linear regression illustrated correlations between PROMIS vs ODI and VAS Back/Leg scores. Independent t-tests and chi-squared tests were utilized to investigate significant differences in HNP measurements between the MCID+ and MCID– groups.RESULTSThere were 88 MLD patients included in the study (Age=44.6±14.9, 38.6% female). PROMIS pain interference and pain intensity were strongly correlated with ODI and VAS Back/Leg (R≥0.505), and physical function correlated with ODI and VAS Back/Leg (R=−0.349) (all p<.01). The strongest MRI predictors of meeting HRQoL MCID were gray disc appearance, HNP area (>116.6 mm²), and Hemi-Area Ratio (>51.8%). MCID+ patients were 2.7 times more likely to have a gray HNP MRI signal than a mixed or black HNP MRI signal in five out of six HRQoL score comparisons (p<.025). MCID+ patients had larger HNP areas than MCID– patients had in five out of six HRQoL score comparisons (116.6 mm²±46.4 vs 90.0 mm²±43.2, p<.04). MCID+ patients had a greater Hemi-Area Ratio than MCID– patients had in four out of six HRQoL score comparisons (51.8%±14.7 vs 43.9%±14.9, p<.05).CONCLUSIONSPatients who met MCID after MLD had larger HNP areas and larger Hemi-HNP Areas than those who did not meet MCID. These patients were also 2.7× more likely to have a gray MRI signal than a mixed or black MRI signal. When accounting for HNP area relative to canal area, patients who met MCID had greater Hemi-HNP canal occupation than patients who did not meet MCID. The results of this study suggest that preoperative MRI parameters can be useful in predicting patient-reported improvement after MLD.     

Poor muscle health and low preoperative ODI are independent predictors for slower achievement of MCID after minimally invasive decompression

Background ContextAlthough some previous studies have analyzed predictors of nonimprovement, most of these have focused on demographic and clinical variables and have not accounted for radiological predictors. In addition, while several studies have examined the degree of improvement after decompression, there is less data on the rate of improvement.PurposeTo identify the risk factors and predictors (both radiological and nonradiological) for slower as well as nonachievement of minimal clinically important difference (MCID) after minimally invasive decompression.DesignRetrospective cohort.Patient SamplePatients who underwent minimally invasive decompression for degenerative lumbar spine conditions and had a minimum of 1-year follow up were included. Patients with preoperative Oswestry Disability Index (ODI) <20 were excluded.Outcome MeasureMCID achievement in ODI (cut off 12.8).MethodsPatients were stratified into two groups (achieved MCID, did not achieve MCID) at two timepoints (early ≤3 months, late ≥6 months). Nonradiological (age, gender, BMI, comorbidities, anxiety, depression, number of levels operated, preoperative ODI, preoperative back pain) and radiological (MRI – Schizas grading for stenosis, dural sac cross-sectional area, Pfirrmann grading for disc degeneration, psoas cross-sectional area and Goutallier grading, facet cyst/effusion; X-ray – spondylolisthesis, lumbar lordosis, spinopelvic parameters) variables were assessed with comparative analysis to identify risk factors and with multiple regression models to identify predictors for slower achievement of MCID (MCID not achieved by ≤3 months) and nonachievement of MCID (MCID not achieved at ≥6 months).ResultsA total of 338 patients were included. At ≤3 months, patients who did not achieve MCID had significantly lower preoperative ODI (40.1 vs 48.1, p<0.001) and worse psoas Goutallier grading (p=.048). At ≥6 months, patients who did not achieve MCID had significantly lower preoperative ODI (38 vs 47.5, p<.001), higher age (68 vs 63 years, p=.007), worse average L1-S1 Pfirrmann grading (3.5 vs 3.2, p=.035), and higher rate of pre-existing spondylolisthesis at the operated level (p=.047). When these and other probable risk factors were put into a regression model, low preoperative ODI (p=.002) and poor Goutallier grading (p=.042) at the early timepoint and low preoperative ODI (p<.001) at the late timepoint came out as independent predictors for MCID nonachievement.ConclusionAfter minimally invasive decompression, low preoperative ODI and poor muscle health are risk factors and predictors for slower achievement of MCID. For nonachievement of MCID, low preoperative ODI, higher age, greater disc degeneration, and spondylolisthesis are risk factors and low preoperative ODI is the only independent predictor.     

Outcomes of cervical disc replacement in patients with neck pain greater than arm pain

BACKGROUND CONTEXTAlthough anterior cervical discectomy and fusion is believed to positively impact a patient's radicular symptoms as well as axial neck pain, the outcomes of cervical disc replacement (CDR) with regards to neck pain specifically have not been established.PURPOSEPrimary: to assess clinical improvement following CDR in patients with neck pain greater than arm pain. Secondary: to compare the clinical outcomes between patients undergoing CDR for predominant neck pain (pNP), predominant arm pain (pAP), and equal neck and arm pain (ENAP).STUDY DESIGNRetrospective review of prospectively collected data.PATIENT SAMPLEPatients who had undergone one- or two-level CDR for the treatment of degenerative cervical pathology and had a minimum of 6-month follow-up were included and stratified into three cohorts based on their predominant location of pain: pNP, pAP, and ENAP.OUTCOME MEASURESPatient-reported outcomes: Neck Disability Index (NDI), Visual Analog Scale (VAS) neck and arm, Short Form 12-Item Physical Health Score (SF12-PHS), Short Form 12-Item Mental Health Score (SF12-MHS), minimal clinically important difference (MCID).METHODSChanges in Patient-reported outcomes from preoperative values to early (<6 months) and late (≥6 months) postoperative timepoints were analyzed within each of the three groups. The percentage of patients achieving MCID was also evaluated.RESULTSOne hundred twenty-five patients (52 pNP, 30 pAP, 43 ENAP) were included. The pNP cohort demonstrated significant improvements in early and late NDI and VAS-Neck, early SF-12 MCS, and late SF-12 PCS. The pAP and ENAP cohorts demonstrated significant improvements in all PROMs, including NDI, VAS-Neck, VAS-Arm, SF-12 PCS, and SF-12 MCS, at both the early and late timepoints. No statistically significant differences were found in the MCID achievement rates for NDI, VAS-Neck, SF-12 PCS, and SF-12 MCS at the late timepoint amongst the three groups.CONCLUSIONSCDR leads to comparable improvement in neck pain and disability in patients presenting with neck pain greater than arm pain and meeting specific clinical and radiographic criteria.