Minimal Clinically Important Difference and Patient-Acceptable Symptom State in Orthopaedic Spine Surgery: A Review

Performance of baseline quartile-stratified minimal clinically important difference estimates was superior to individual minimal clinically important difference estimates when compared with a gold standard comparator of important change

ABSTRACT

A variety of minimal clinically important difference (MCID) estimates are available to distinguish subgroups with differing outcomes. When a true gold standard is absent, latent class growth curve analysis (LCGC) has been proposed as a suitable alternative for important change. Our purpose was to evaluate the performance of individual and baseline quartile-stratified MCIDs. The current study included data from 346 persons with baseline and 12-month postoperative outcome data from KASTPain, a no-effect randomized clinical trial conducted on persons with knee arthroplasty and pain catastrophizing. Subgroup trajectories from LCGC were used as a gold standard comparator. Minimal clinically important difference-specific trajectories of recovery were calculated for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain, Disability and EuroQol-5 Dimension Visual Analogue Scale of self-reported health. The latent Kappa (K l ) chance-corrected agreement between MCIDs and LCGCs were estimated to indicate which MCID method was best at detecting important change. For all 3 outcomes, the average latent class probabilities ranged from 0.90 to 0.99, justifying the use of LCGCs as a gold standard. The K l for LCGC and individual MCIDs ranged from 0.21 (95% CI = 0.13, 0.28) to 0.52 (95% CI = 0.41, 0.66). Baseline quartile-stratified K l for WOMAC Pain and Disability were 0.85 (95% CI = 0.78, 0.92) and 0.74 (95% CI = 0.68, 0.83), respectively. Classification errors in individual MCID estimates most likely result from ceiling effects. Minimal clinically important differences calculated for each baseline quartile are superior to individually calculated MCIDs and should be used when latent class methods are not available. Use of individual MCIDs likely contribute substantial error and are discouraged for clinical application.

The impact of obesity on postoperative and perioperative outcomes in lumbar spine surgery: a systematic review and meta-analysis

BACKGROUND CONTEXT

Obesity is increasingly prevalent globally and is associated with various health issues, including spine-related disorders. Previous studies have shown mixed results regarding the impact of obesity on spine surgery outcomes.

PURPOSE

This meta-analysis aims to evaluate the effects of obesity on perioperative and postoperative outcomes in spine surgery patients.

STUDY DESIGN/SETTING

We performed a systematic review and meta-analysis of prospective and retrospective studies comparing outcomes between obese and nonobese spine surgery patients.

PATIENT SAMPLE

The meta-analysis included 35,639 patients, of which 9,369 were obese (BMI≥30 kg/m²) and 26,270 were nonobese (BMI<30 kg/m²).

OUTCOME MEASURES

Primary outcomes included patient-reported outcome measures (PROMs) such as the Oswestry Disability Index (ODI) and the Visual Analog Scale (VAS) for leg and back pain. Secondary outcomes involved perioperative measures like estimated blood loss (EBL), operative time, and length of stay (LOS), as well as complication and reoperation rates.

METHODS

Following PRISMA guidelines, four databases were searched for relevant studies. The quality of included studies was assessed using the Cochrane Risk of Bias tool. Mean differences were used to quantify the differences in PROMs and perioperative outcomes. Odds ratios were used to analyze differences in complication rates.

RESULTS

Obese patients had similar PROMs compared to nonobese patients, with differences not exceeding the minimal clinically important difference (MCID). However, obese patients experienced longer operative times, greater EBL, and extended hospital stays. They also had higher rates of postoperative complications such as Dural tears, infections, and reoperations.

CONCLUSIONS

While obesity is associated with certain perioperative challenges, the postoperative recovery in terms of pain and disability appears comparable between obese and nonobese patients. Spine surgeons should be aware of the increased perioperative risks but can reassure obese patients of similar long-term outcomes postsurgery.

The Patient Acceptable Symptom State (PASS) has Little Utility Before Total Hip or Knee Arthroplasty

BACKGROUND

A better understanding of patient's a preoperative symptom state may assist in a more holistic evaluation of patients pursuing total joint arthroplasty (TJA). This study aimed to determine factors associated with preoperative Patient Acceptable Symptom State (PASS) scores in TJA patients and to determine the predictive ability of patient-reported outcome measures (PROMs) for achieving PASS preoperatively.

METHODS

All patients undergoing primary, elective TJA between January and October 2021 at a single institution and who had completed a preoperative PASS, preoperative Patient-Reported Outcome Measurement Information System (PROMIS) questionnaires, and joint-specific PROMs were eligible for inclusion. Descriptive statistics and independent samples t-tests were utilized. Receiver operating characteristic curves and area under the curve analyses were created to determine threshold values for PROMs representing PASS achievement.

RESULTS

A total of 287 total hip arthroplasty (THA) patients and 378 total knee arthroplasty (TKA) patients completed PASS preoperatively, with 12.9% of THA patients and 29.6% of TKA patients reporting acceptable symptom states. The PASS responses were associated with PROMIS Physical Function (PROMIS-PF) (P < 0.001) but not Hip Dysfunction and Osteoarthritis Score, Joint Replacement (P = 0.073) scores in THA. The PASS responses were similarly associated with PROMIS-PF (P < 0.010) as well as Knee Injury and Osteoarthritis Outcome Score, Joint Replacement (P = 0.030) scores in TKA. The Hip Dysfunction and Osteoarthritis Score, Joint Replacement and PROMIS-PF threshold values of 55.6 and 40, respectively, only weakly predicted preoperative PASS achievement in THA. The Knee Injury and Osteoarthritis Outcome Score, Joint Replacement and PROMIS-PF threshold values of 52.5 and 39, respectively, only weakly predicted preoperative PASS achievement in TKA.

CONCLUSIONS

In patients undergoing THA or TKA, 12.9 and 29.6% of patients were satisfied with their symptoms before surgery, respectively. None of the threshold values for the assessed PROMs strongly predict PASS achievement. Given that not all patients indicated for TJA reported unacceptable health states, these findings question the validity of the PASS questionnaire preoperatively.

Perspective on Intradiscal Therapies for Lumbar Discogenic Pain: State of the Science, Knowledge Gaps, and Imperatives for Clinical Adoption

Specific clinical diagnostic criteria have established a consensus for defining patients with lumbar discogenic pain. However, if conservative medical management fails, these patients have few treatment options short of surgery involving discectomy often coupled with fusion or arthroplasty. There is a rapidly-emerging research effort to fill this treatment gap with intradiscal therapies that can be delivered minimally-invasively via fluoroscopically guided injection without altering the normal anatomy of the affected vertebral motion segment. Viable candidate products to date have included mesenchymal stromal cells, platelet-rich plasma, nucleus pulposus structural allograft, and other cell-based compositions. The objective of these products is to repair, supplement, and restore the damaged intervertebral disc as well as retard further degeneration. In doing so, the intervention is meant to eliminate the source of discogenic pain and avoid surgery. Methodologically rigorous studies are rare, however, and based on the best clinical evidence, the safety as well as the magnitude and duration of clinical efficacy remain difficult to estimate. Further, we summarize the US Food and Drug Administration's (FDA) guidance regarding the interpretation of the minimal manipulation and homologous use criteria, which is central to designating these products as a tissue or as a drug/device/biologic. We also provide perspectives on the core evidence and knowledge gaps associated with intradiscal therapies, propose imperatives for evaluating effectiveness of these treatments and highlight several new technologies on the horizon.

Patient-Reported Outcome Measures following Coblation Nucleoplasty for Cervical Discogenic Dizziness

BACKGROUND

There is little research in the literature comparing the efficacy of coblation nucleoplasty with conservative treatment in the treatment of cervical discogenic dizziness and reporting the achieved rate of minimal clinically important differences (MCID) and patient acceptable symptom state (PASS) after surgery. This retrospective study aims to explore the patient-reported outcome measures (PROM) following coblation nucleoplasty for cervical discogenic dizziness and to compare the therapeutic effect of coblation nucleoplasty with prolonged conservative treatment.

METHODS

Sixty-one patients with cervical discogenic dizziness and a positive intradiscal diagnostic test eligible for single-level cervical coblation nucleoplasty were included in the study. Among these 61 patients, 40 patients underwent cervical coblation nucleoplasty, while the remaining 21 patients refused surgery and received continued conservative treatment. The primary PROMs were the intensity and frequency of dizziness and secondary PROMs were related to the neck disability index (NDI) and visual analog scale (VAS) for neck pain (VAS-neck) during a 12-month follow-up period. Moreover, the achieved rate of MCID and PASS in both groups was assessed 12 months after surgery.

RESULTS

Dizziness intensity, dizziness frequency, VAS-neck score, and NDI score were significantly improved from the baseline at all follow-up time points in both treatment groups, except for showing no significant improvement in dizziness frequency in the conservative treatment group at 6 and 12 months after surgery. However, at each follow-up time point, the above indexes were lower in the surgery group than in the conservative treatment group. In addition, the achieved rates for PASS and MCID in all indexes in the surgery group were significantly higher than those in the conservative treatment group at 12 months after surgery.

CONCLUSIONS

Cervical coblation nucleoplasty significantly improved the intensity and frequency of dizziness, neck pain, and NDI in patients with cervical discogenic dizziness, and the results were superior to those from prolonged conservative treatment. Meanwhile, cervical coblation nucleoplasty is a good choice for patients with chronic neck pain and refractory cervical discogenic dizziness who have not demonstrated the indications for open surgery and have not responded well to conservative treatment.