State-of-the-art Applications of Patient-Reported Outcome Measures in Spinal Care

Preoperative Oswestry Disability Index Should not be Utilized to Determine Surgical Eligibility for Patients Requiring Lumbar Fusion for Degenerative Lumbar Spine Disease

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate how preoperative Oswestry Disability Index (ODI) thresholds might affect minimal clinically important difference (MCID) achievement following lumbar fusion.

SUMMARY OF BACKGROUND DATA

As payers invest in alternative payment models, some are suggesting threshold cutoffs of patient-reported outcomes (PROMs) in reimbursement approvals for orthopedic procedures. The feasibility of this has not been investigated in spine surgery.

MATERIALS/METHODS

We included all adult patients undergoing one to three-level primary lumbar fusion at a single urban tertiary academic center from 2014 to 2020. ODI was collected preoperatively and one year postoperatively. We implemented theoretical threshold cutoffs at increments of 10. MCID was set at 14.3. The percent of patients meeting MCID were determined among patients "approved" or "denied" at each threshold. At each threshold, the positive predictive value (PPV) for MCID attainment was calculated.

RESULTS

A total 1368 patients were included and 62.4% (N=364) achieved MCID. As the ODI thresholds increased, a greater percent of patients in each group reached the MCID. At the lowest ODI threshold, 6.58% (N=90) of patients would be denied, rising to 20.2%, 39.5%, 58.4%, 79.9%, and 91.4% at ODI thresholds of 30, 40, 50, 60, and 70, respectively. The PPV increased from 0.072 among patients with ODI>20 to 0.919 at ODI>70. The number of patients denied a clinical improvement in the denied category per patient achieving the MCID increased at each threshold (ODI>20: 1.96; ODI>30: 2.40; ODI>40: 2.75; ODI>50: 3.03; ODI>60: 3.54; ODI>70: 3.75).

CONCLUSION

Patients with poorer preoperative ODI are significantly more likely to achieve MCID following lumbar spine fusion at all ODI thresholds. Setting a preoperative ODI threshold for surgical eligibility will restrict access to patients who may benefit from spine fusion despite ODI>20 demonstrating the lowest predictive value for MCID achievement.

LEVEL OF EVIDENCE

3.

Readability of Patient-Reported Outcomes in Spine Surgery and Implications for Health Literacy

STUDY DESIGN

Observational study.

OBJECTIVE

To evaluate the readability of commonly utilized patient-reported outcome measures (PROMs) in spine surgery.

SUMMARY OF BACKGROUND DATA

Although studies have evaluated patient education materials, discharge instructions, and informed consent forms in spine surgery, there is a dearth of literature on the readability of PROMs despite widespread health illiteracy. Without knowledge of PROM readability, it is unclear whether these measures are able to be understood by the average spine patient.

MATERIALS AND METHODS

We analyzed all commonly utilized nonvisual PROMs within the spinal literature and uploaded PROMs into an online readability calculator. The Flesch Reading Ease Score (FRES) and Simple Measure of Gobbledygook (SMOG) Index were collected. A FRES>79 or SMOG<7 was considered readable by the general population per American Medical Association and Centers for Disease Control guidelines. A stricter threshold recommended in health care (SMOG <6 or FRES>89) was then used to further review readability.

RESULTS

Seventy-seven PROMs were included. Based on FRES, the mean readability of all PROMs was 69.2 ± 17.2 (range, 10-96.4), indicating an average eighth to ninth-grade reading level. The mean readability score categorized by the SMOG Index was 8.12 ± 2.65 (range, 3.1-25.6), representing an eighth-grade reading level. Compared with the reading level of the general population, 49 (63.6%) PROMs are written above the United States literacy level, according to FRES. Using stricter definitions of readability, 8 PROMs were considered readable, including PROM Information System pain behavior (FRES: 96.4 and SMOG: 5.2), PROM Information System sleep disturbance (SMOG: 5.6), Neck Pain and Disability Scale (SMOG: 4.3), and Zung Depression Scale (SMOG: 3.1).

CONCLUSIONS

Most PROMs utilized in spine surgery require an average reading competency far above the average patient's comprehension. This may have a meaningful impact on understanding PROM instruments and may affect the accuracy of complete surveys and the rates of incompletion.

H-Wave® Device Stimulation for Chronic Low Back Pain: A Patient-Reported Outcome Measures (PROMs) Study

INTRODUCTION

Chronic low back pain (cLBP) is a problem globally, creating a tremendous economic burden. Since conventional treatments often fail, various forms of electrical stimulation have been proposed to improve function and decrease pain. Patient-reported outcome measures (PROMs) have not been adequately reported in the electrical stimulation literature.

METHODS

A retrospective independent statistical analysis was conducted on PROMs data for users of H-Wave® device stimulation (HWDS) collected by the device manufacturer over a period of 4 years. Final surveys for 34,192 pain management patients were filtered for pain chronicity limited to 3-24 months and device use of 22-365 days, resulting in 11,503 patients with "all diagnoses"; this number was then reduced to 2711 patients with nonspecific cLBP, sprain, or strain.

RESULTS

Reported pain was reduced by 3.12 points (0-10 pain scale), with significant (≥ 20%) relief in 85.28%. Function/activities of daily living (ADL) improved in 96.36%, while improved work performance was reported in 81.61%. Medication use decreased or stopped in 64.41% and sleep improved in 59.76%. Over 96% reported having expectations met or exceeded, service satisfaction, and confidence in device use, while no adverse events were reported. Subgroup analyses found positive associations with longer duration of device use, home exercise participation, and working, whereas older age and longer pain chronicity resulted in reduced benefit. Similar analysis of the larger all-diagnoses cohort demonstrated near-equivalent positive outcomes.

CONCLUSION

Treatment outcomes directly reported by cLBP HWDS patients demonstrated profound positive effects on function and ADL, robust improvement in pain perception, and additional benefits like decreased medication use, better sleep, and improved work performance, representing compelling new evidence of treatment efficacy.

Values derived from patient reported outcomes in spine surgery: a systematic review of the minimal clinically important difference, substantial clinical benefit, and patient acceptable symptom state

PURPOSE

While patient reported outcome measures (PROMs) define value in spine surgery, several values such as minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state (PASS) help guide the interpretation of PROMs and identify thresholds of clinical significance. Significant variation exists in reported values and their calculation, so the primary objective of this study was to systematically review the spine surgery literature for metrics of clinical significance derived from PROMs.

METHODS

We conducted a query of PubMed/MEDLINE and Scopus databases from inception to January 1, 2023, for studies that derived quantitative metrics (e.g., SCB, MCID, PASS) from PROMs in the setting of spine surgery with minimum 1-year follow-up. Details regarding the specific PROMs were collected including which PROM was measured, whether anchor- or distribution-based methods were utilized, the specific calculations, and the recommended value for a given PROM based on all evaluated calculations.

RESULTS

Thirty-seven studies of 21,780 patients were included. The most commonly evaluated PROM-derived value was the MCID (n = 28), followed by PASS (n = 6) and SCB (n = 4). Twenty-one studies only utilized anchor-based calculations, 15 utilized both anchor-based and distribution-based methods, and one only utilized distribution-based calculations. The most commonly evaluated legacy PROMs were the Oswestry Disability Index (ODI) (N = 11, MCID range 4-20) and visual analog scale back pain (N = 5, MCID range 0.5-4.6). All 10 studies that derived SCB or PASS utilized the receiver operating characteristic methods. Among the six studies deriving a PASS value, four only evaluated ODI, identifying PASS ranging from 5 to 22.

CONCLUSION

While calculated measures of clinical significance such as MCID, PASS, and SCB exist, significant heterogeneity exists in the current literature. Current shortcomings include a wide variability of reported value thresholds across the literature, and limited applicability to more heterogenous patient populations than the targeted cohorts included in published investigations. Continued investigations that apply these methods to heterogenous, large-scale populations can help increase generalizability and validity of these measures.

LEVEL OF EVIDENCE

III.