Comment on “New predictive factors for prolonged operation time of laparoscopic posterior retroperitoneal adrenalectomy; retrospective cohort study”

Abstract

Dear Editor, A retrospective study based on a Korean population recently explored predictors associated with prolonged operation time after laparoscopic posterior retroperitoneal adrenalectomy (LPRA) [1]. In this study involving 284 patients, multivariate logistic regression analysis identified several predictors associated with prolonged operation time after LPRA, such as male (OR = 2.540), pheochromocytoma (OR = 3.669), and depth of descended adrenal tumor location to kidney (OR = 3.793). The authors’ great contribution provides the main evidence for the prolongation of operation time after LPRA, and helps clinicians to make timely adjustments according to the individual characteristics before surgery, thus helping to reduce the operation time. However, the following concerns need to be further addressed and clarified. First, as described in Table 1, different sites (Right versus Left) were not significantly associated with prolonged operation time (p value = 0.583). However, in multivariate logistic regression analysis, it was found that right site was associated with prolonged operation time compared to left side (adjusted OR = 2.499, 95% CI: 1.086 to 5.748, p value = 0.031, Table 2), which was extremely puzzling. In general, if the percentages of prolonged operation time at different sites were similar (50.7% in right site and 49.3% in left site), it would be almost impossible to find that different sites were associated with prolonged operation time in regression analysis. We are curious how this conclusion was reached. For this concern, if the authors could provide more evidence or explanation, it will be very helpful to reduce the confusion of readers. Second, it should be emphasized that it is important to know whether continuous variables are normally or skewed distributed before data analysis. Obviously, in Table 3, the standard deviation (SD) of periadrenal fat volume on the right side is 36.07, while the mean is 30.53, suggesting that periadrenal fat volume does not correspond to normal distribution but skewed distribution. Similarly, this phenomenon was also found in periadrenal fat volume on the left side (Table 3), that is, the value of SD (58.65) was greater than the mean value. In that case, median and interquartile range (IQR) should be used to describe periadrenal fat volume and Mann-Whitney U test [2] or Kolmogorov–Smirnov test [3] should be used to compare the difference between groups instead of Student’s t-test. Although the final conclusions will not change significantly, appropriate statistical analysis can help to obtain accurate and reliable results. Third, factors related to anesthesia should not be ignored. Currently, American Society of Anesthesiologists (ASA) score is one of the most used tools to evaluate the risk of anesthesia and surgery in clinical practice, and its predictive value has been confirmed by extensive studies. Halil et al. [4]. demonstrated that ASA Score could be used to predict increased estimated blood loss (EBL) and length of stay (LOS) in patients treated with laparoscopic adrenalectomy (LA). Therefore, anesthesia related factors, such as ASA score, should not be overlooked when exploring factors associated with prolonged operation time in patients underwent LPRA treatment. Provenance and peer review Commentary, internally reviewed. Ethical Approval That’s no need for Ethical Approval, since this is a letter to the editor. Sources of funding None. Author contribution Jiao Wang and Juncai Tu participate in study design and writing. Trial registry number Name of the registry: Unique Identifying number or registration ID: Hyperlink to your specific registration (must be publicly accessible and will be checked): This is a letter to the editor. Guarantor Jiao Wang and Juncai Tu. Declaration of competing interest None. Acknowledgment None.