To the Editor:—
We read with interest the article by Blumenthal et al. 1about effectiveness of continuous ropivacaine infusion at the iliac crest donor site. This study seems to confirm the results of Brull et al. 2obtained with continuous bupivacaine infusion. However, several points deserve some comments from the authors before their conclusions can be accepted.
First, the primary goal and the calculation of the number of patients needed for the study deserve clarification. Was this study built to demonstrate a reduction in pain scores at rest, at movement, or both, and if so, at 24 h or 48 h or both? This is of importance because it has direct impact on the accuracy of the calculation of the number of patients needed to test the null hypothesis and because the use of multiple statistical comparisons dramatically increases the α risk.
Second, the chronic analgesic therapy of the patients at 3 months is not reported. Because of the highly significant difference in the pain at the iliac crest during motion between the two groups, it would be important to determine whether analgesic therapy was accurately administered in the two groups at that time. Otherwise, this would represent a possible confounding factor contributing to artificially exacerbate the difference in pain scores between groups at 3 months.
Third, the authors make a case that higher patient satisfaction and lower pain score during motion 3 months after surgery are present in the ropivacaine group. Although these data are potentially very interesting, maybe more interesting than the primary goal itself (postoperative short-term reduction in pain scores), they correspond only to a secondary endpoint. Therefore, we think it is premature to state, as the authors did, that “the benefit of this technique is still present after 3 months.” To report data on the social consequences of persistent pain at the iliac crest at 3 months (e.g. , ability to work, quality of daily life) would have strengthened the potential clinical impact of the current study.
*Beaujon University Hospital, Clichy, France. firstname.lastname@example.org.