Response to Letter to the Editor Regarding “Uniportal Versus Biportal Endoscopic Decompression for the Treatment of Lumbar Spinal Stenosis: A Systematic Review and Updated Meta-Analysis”

We thank our esteemed colleagues for their thoughtful engagement with our article. We appreciate the insights and clarify them in the comments below.

Firstly, it was noted that the study by Wu et al ¹ was classified as a randomized controlled trial (RCT) in this review. Indeed, while Wu et al ¹ described their design as a prospective cohort study, the methodology involved enrolling patients for endoscopic lumbar decompression without pre-specifying whether they would undergo uniportal or biportal surgery, followed by prospective allocation to each group using a random-number generator. This process constitutes true random allocation prior to the intervention, which is the defining criterion for the use of the Cochrane Risk of Bias (ROB-2) tool.^2,3 We agree that the study lacked certain hallmarks of a fully developed RCT, such as trial registration and allocation concealment. However, these limitations were reflected in its overall “some concerns” classification in the ROB-2 assessment.

Secondly, there was an expressed concern that this classification could influence the meta-analysis weighting, risk of bias assessment, and GRADE evaluation. We would like to clarify that this classification did not impact the pooled analyses or the certainty of evidence. No subgroup analyses based on study design were conducted, and meta-analytic weights were determined by statistical variance, rather than study design classification. Furthermore, sensitivity analyses confirmed that no individual study, including Wu et al, ¹ significantly altered the pooled results. Thus, this classification had no effect on the statistical results or the certainty of the evidence.

In summary, the decision to classify the study by Wu et al ¹ as an RCT for the purpose of this review was based on the presence of prospective patient enrollment and randomized allocation before the intervention, consistent with Cochrane guidance for ROB-2 use.^2,3 Importantly, this classification had no influence on the meta-analytic findings or conclusions of our review.