Polytomous Rasch Analyses of Surgeons’ Decision-Making on Choice of Procedure in Endoscopic Lumbar Spinal Stenosis Decompression Surgeries

Discussion

Spine surgeons rely on their personal perceptions and clinical experiences when making crucial surgical decisions. In the fast-moving field of endoscopic spine surgery, 3 techniques have emerged—(1) the transforaminal,1–5 (2) the interlaminar,6–11 and (3) the UBE12–16 techniques. The current clinical evidence suggests that all 3 produce favorable clinical outcomes in treating lumbar spinal stenosis. While high-grade clinical evidence and clinical guidelines are essential in establishing standard-care parameters, the nuanced nature of each patient’s case means that a surgeon’s perception of what is best for the patient may supersede these clinical guidelines or protocol changes suggested by recent high-grade clinical studies. Surgeons spend years honing their craft, developing intuition, and cultivating an in-depth understanding of their patient’s unique needs, fears, and expectations. This intimate, patient-centric approach fosters trust and understanding that standardized guidelines alone cannot achieve. Therefore, even in the face of established evidence or guidelines, spine surgeons might prioritize their perceptions of optimal patient care, believing that their hands-on experience and familiarity with individual patients provide insights that generalized recommendations might overlook.

Furthermore, spine surgeons’ decisions are influenced by complex factors, including their training, experience, and, importantly, their perceptions of the best care for their patients. The patient’s anatomy, medical comorbidities, and painful pathology, particularly after previous surgery, are additional confounding factors that influence the surgeon’s perception, developed through years of hands-on experience. These perceptions often become the primary guiding force because spine surgeons may feel that even the highest-grade evidence provided by double-blinded randomized prospective clinical trials may not apply to their particular patient. After all, the derived clinical guidelines were often developed from studies with their own limitations, such as inclusion and exclusion criteria, which might not always encompass the broad spectrum of patients surgeons encounter in real-world settings. In addition, the patient-surgeon relationship plays a pivotal role. Spine surgeons gain insights into a patient’s lifestyle, occupation, aspirations, and fears through discussions. These insights, which may go beyond the clinical guidelines’ foundational framework, can significantly influence surgical decisions, particularly in early adoption scenarios. Through continuous education and peer interactions, spine surgeons often employ new methods they perceive to offer better patient outcomes. Endoscopic spine surgery is one such example, where its most recent innovations and techniques are yet to be fully integrated into formal guidelines. Since the on-the-ground decision-making often leans heavily on spine surgeons’ perceptions of best patient care, stemming from their expertise, experience, and the trust they build with their patients, the authors of this study were keenly interested in better understanding the surgical decision-making when recommending the endoscopic spinal surgery platform in the treatment of lumbar spinal stenosis. They surveyed 296 spine specialists with a response rate of 49.1%. Of the 83 surgeons who completed the survey, 44.6% were neurosurgeons, 36.1% were orthopedic surgeons, and another 12% were exclusively devoted to spinal surgeries. The majority of responding surgeons (66.3%) worked in private practice and represented a myriad of respectable spine societies.

The polytomous Rasch model analysis25,26 is suitable for psychometrically measuring the intensity of agreement by employing fit statistics alongside visual analysis to determine whether a group of items forms a unidimensional scale with consistent interval characteristics, thus maintaining scale scores across diverse groups. Central to the model is the principle of invariance, with the analysis aimed at pinpointing data irregularities that could jeopardize this uniformity in measurement. Identifying these irregularities enhances comprehension of the attribute under assessment.27 Traditionally, the objective is to refine the data’s alignment with the model’s criteria until there is an adequate correlation to ensure stable measures in a distinct test item. This objective can be realized by removing or altering items, creating new ones, occasionally excluding specific individuals, or extending the assessment to additional person groups. In the authors’ application, we used the Rasch analysis to understand the psychometrics of surgical decision-making better when choosing between the various lumbar endoscopic decompression surgeries to treat spinal stenosis. In the absence of an right or wrong external unbiased criterion to further calibrate the questions before launching the survey, the authors employed the Rasch methodology as an examination tool which primarily uses internal criteria to evaluate and measure responses to items within a test or survey and report on those in which the expected order of response categories did progress in a clear, linear manner, and on those that did not. We intentionally did not collapse item characteristics to improve the fit of the model. Instead, we merely analyzed the fit to expose disordered thresholds, especially for those persons located at the maximum value for a category, disagreeing with the item where selecting a category strongly disagree is never the most probable response. Descriptive statistics alone would never be able to expose the intensity of agreement that ultimately reflects the surgeon’s ability while highlighting the ease of endorsement by selecting an item difficulty. For example, the mean logit location analysis showed more intense partial agreement (Figure 4) for the individual categories of the transforaminal rather than the interlaminar test item, indicating that the transforaminal technique was considered the best lumbar endoscopic stenosis decompression procedure by responding surgeons contrary to the descriptive statistics outcome (Figure 5). In comparison, the items testing the importance of endoscopic instruments, clinical outcomes, rehabilitation, and the relevance of UBE had disordered thresholds (Figure 7) and broader spread of logit locations (Figure 6). The person-item maps also illustrate that 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 psychometric Rasch analysis can expose these otherwise hidden nuances in surgical decision-making by logarithmically transforming person and item positions, which then can be depicted on a unified continuum using a standard measurement unit called a logit, thus transitioning ordinal data into equal-interval data. An item’s position can be understood as the overall challenge responding surgeons faced in positively answering a specific item. Items situated to the right of the continuum’s central point of 0 logits (meaning they have a positive logit value) present more of a challenge for endorsement than those on the left (with a negative logit value). The item’s content clarifies what constitutes more or less of the measured concept. Items of higher intensity are typically confirmed solely by individuals with elevated cumulative scores across various items. This new approach to assessing spine surgeons’ thought processes was endorsed by the Interamerican Society for Minimally Invasive Spine Surgery (SICCMI), the International Society for Minimal Intervention in Spinal Surgery (ISMISS), the Mexican Spine Society (AMCICO), the Brazilian Spine Society (SBC), the Society for Minimally Invasive Spine Surgery (SMISS), the Korean Minimally Invasive Spine Society (KOMISS), and the International Society for the Advancement 0f Spine Surgery (ISASS) as their leadership thought it may improve the implementation of evidence-based protocol change dictated by technological advances.

In contrast, simpler or less intense items tend to receive affirmation from a broader respondent base, encompassing even those with lower aggregate scores. In our study, the easiest items to agree on were comfort level with the endoscopic procedure and patient-related factors, suggesting that these items are less controversial when selecting patients for lumbar endoscopic stenosis decompression. Regarding the preferred procedure, the items “interlaminar” and “transforaminal technique” were the easiest to agree on, indicating that surgeons had high confidence in these procedures being effective in treating lumbar spinal stenosis. The most challenging items to agree on were clinical outcomes and postoperative rehabilitation, suggesting that patient selection is most controversially influenced by concerns regarding the ability to achieve adequate clinical outcomes and recovery of day-to-day functioning with the endoscopic surgery platform when treating patients for lumbar spinal stenosis. The UBE procedure was the most controversial and the hardest for surgeons to agree on its suitability for endoscopic lumbar spinal stenosis treatment. While one possible explanation for the disorderly UBE item thresholds is the lack of scale sensitivity to capture nuanced differences in respondents’ attitudes or perceptions, leading to unexpected jumps or reversals in category use, the more reasonable explanation is the relative novelty of this emerging endoscopic surgical technique with less adoption, surgeon acceptance, or broader clinical experience than with the other two more traditional transforaminal and interlaminar techniques. Future closer examination of the disordered responses found in this study may potentially overcome the limitations inherent to the authors’ current study methodology and findings.