Insights on High-Value Procedures From the ISASS 4-Part Webinar Series on Current and Emerging Techniques in Endoscopic Spine Surgery Based on Surgeon Experience

Abstract

Background: The authors conducted a comprehensive review and integration of insights from 4 webinars hosted by the International Society for the Advancement of Spine Surgery (ISASS) to arrive at recommendations for best clinical practices for guideline development for endoscopic spine surgery. This perspective article discusses the limitations of traditional surgical trials and amalgamates surgeons' experience and research on various cutting-edge techniques.

Methods: Data were extracted from surveys conducted during each webinar session involving 3639 surgeons globally. The polytomous Rasch model was employed to analyze responses, ensuring a robust statistical assessment of surgeon endorsements and educational impacts and focusing on operative nuances and experience-based outcomes. Bias detection was performed using the differential item functioning test.

Results: The ISASS webinars provided a dynamic platform for discussing advances in endoscopic spine surgery, identifying a range of high-value procedures from basic discectomies to complex lumbar interbody fusions. Each high-value endoscopic spine surgery was highlighted in separate peer-reviewed publications, which form the basis for this summary document that synthesizes key takeaways from these webinars. High-value clinical applications of endoscopic spine surgery, primarily defined as higher-intensity endorsement transformation from the pre- to postwebinar survey with a shift to higher mean logit locations of test items both with unbiased and orderly threshold progression, were: (a) Percutaneous interlaminar endoscopic decompression for lateral canal stenosis, (b) transforaminal debridement of low-grade degenerative spondylolisthesis, (c) transforaminal full-endoscopic interbody fusion for hard disc herniation, (d) endoscopic standalone lumbar interbody fusion, (e) endoscopic debridement of spondylolytic spondylolisthesis, and (f) posterior cervical foraminotomy for herniated disc and bony stenosis.

Conclusions: The ISASS webinar series has significantly impacted surgeons' education and contributed to the identification of high-value endoscopic spine surgery practices that may serve as a cornerstone for surgeon training standards, policy, and guidelines development. Ongoing research on technological advancements and expansions of clinical indications combined with systematic review is expected to refine the recommendations on high-value endoscopic spinal surgeries recommended for enhanced reimbursement.

Clinical relevance: Assessing surgeon confidence and acceptance of endoscopic spinal surgeries using polytomous Rasch analysis.

Level of evidence: Level 2 (inferential) and 3 (observational) evidence because Rasch analysis provides statistical validation of instruments rather than direct clinical outcomes.

Keywords: Rasch analysis; bias detection; clinical guidelines development; endoscopic spine surgery; high-value surgical procedures; surgeon experience; surgical trial limitations.

Figure 1

Shown are exemplary plots of a polytomous Rasch partial agreement analysis to assess spine surgeons’ level of endorsement of 5 test items (patient outcomes, comfort with the procedure, instruments, patient factors, and rehabilitation) regarding a commonly performed lumbar decompression surgery. Shown is the resulting Wright plot on the left. The blue horizontal bars correspond to the responding surgeons’ latent traits written in logits (log odds) as estimates of true intervals of item difficulty and surgeon ability. The surgeons represented by horizontal bars at the top indicated a higher level of endorsement for the individual test components (positive logits) than those on the bottom (negative logits). On the right, the higher-level endorsement items are listed at the top vs the easier-to-agree-on items on the bottom. Each item may be visually inspected using its item characteristic curve (ICC) to assess the alignment between anticipated and actual values. An exemplary ICC plot is displayed in the top right graph for comfort and familiarity with the tested spine surgery. The dots graphically denote the average response of individuals in each class interval, while the solid blue curve represents the expected values predicted by the Rasch model. The corresponding person-item map (bottom right) shows the logarithmically transformed person and item positions on a unified continuum using the logit measurement unit, transitioning ordinal data to equal-interval data. This method charts both person and item positions (in logits) along the x-axis. Within Rasch modeling, these values are labeled as “locations” rather than “scores.” A surgeon’s logit location indicates their natural log odds of agreement with a series of items. Individuals with pronounced adherence to the considered attitude affirm items favorably, positioning them further to the right on the scale. The solid dots indicate the mean person location scores. The items “comfort level with the exemplary lumbar decompression procedure” and “patient-related factors” were the easiest to agree on. These items also had the smallest spread of logit locations. The most challenging item to agree on was “clinical outcomes” and “postoperative rehabilitation.” This type of Rasch analysis can expose more intense partial agreement with a test item—in this case, a commonly performed lumbar spinal decompression procedure. The person-item maps also illustrate that items were reasonably well distributed. However, some surgeons could not be measured as reliably as the majority by this set of items, indicating the test items were either too intense or not intense enough for them. The red circles highlight these areas. The analysis also showed disordered thresholds of endorsement for the 5 test items shown in this exemplary plot, suggesting that surgeons had difficulty consistently discriminating between response categories ranging from strongly disagree (1), disagree (2), agree (3), and to strongly agree (4)—a problem observed when there are too many response options (all disordered items shown in red). Examining the order and location of these test items reveals an uneven distribution of the ranked order of item difficulties or intensities along the logit continuum illustrating the true complexity of real-world surgical decision-making—data that should be integrated into traditionally developed clinical guidelines to keep the up-to-date.

Figure 2

The item characteristic curves generated from prewebinar survey responses regarding percutaneous endoscopic lumbar interbody fusion (PELIF) as part of a differential item functioning (DIF) detection process to detect item bias between orthopedic and neurosurgeons using the difNLR() and difORD() functions. Specifically, when DIF is identified in an item, 2 distinct curves are generated: 1 for the reference group (orthopedic surgeons) and another for the focal group (neurosurgeons). Alongside these curves, empirical probabilities are visualized as points, which indicate the proportion of correct responses relative to the participant’s ability level and group. The size of these points reflects the number of respondents at each ability level which showed a significant difference between orthopedics (reference group) and neurosurgeons (focal group) with the statistics for prewebinar DIF detection of 0.8548 and a P value of 0.355 compared with postwebinar DIF detection of 15.485 and a P value of <0.001 suggesting significant bias in the merit assessment of PELIF between orthopedic and neurosurgeons with disorderly responses in the item’s midsection while maintaining a good discriminatory function between high and low endorsement.