“What is the significance of the head-to-body delivery interval in shoulder dystocia?”
WILLIAM A. GROBMAN, MD, MBA (EXAMINING THE EVIDENCE; DECEMBER 2011)
In shoulder dystocia, 4 minutes is an important cutoff
Although I appreciate Dr. Grobman’s commentary on our article on the relationship between the head-to-body delivery interval in shoulder dystocia and neonatal depression, I am disappointed that he did not address its main point.1
Dr. Grobman begins his analysis by summarizing the information we present about the relationship between the duration of shoulder dystocia and neonatal depression. He notes one finding of our study—one that is fairly obvious and, as we acknowledged in our study, has been commented on many times before: that there is a correlation between the duration of shoulder dystocia and the extent of neonatal complications.
What Dr. Grobman does not mention, however, is the most significant finding of our study: that, by 4 minutes into a shoulder dystocia, all of the neonates in uncomplicated cases of shoulder dystocia had been born. It is this finding, with its implications for the timing and intensity of delivery efforts during shoulder dystocia, that is new and previously unpublished.
Instead of discussing this new observation, Dr. Grobman writes at some length about the concepts of selection bias and ascertainment bias. These concepts may have been relevant if the main finding of our article had centered on the difference between control and case groups. However, our main finding in no way involved a comparison between the two groups.
Dr. Grobman’s commentary may be interesting from the point of view of how one should statistically analyze a study, but he overlooks what is most important in our article and applies his statistical analysis in a way that is irrelevant to our article’s most important conclusion.
Henry Lerner, MD
Newton, Mass
Dr. Grobman responds Issues regarding types of bias are indeed relevant
I appreciate Dr. Lerner’s comments, although I disagree with his sentiment. I chose to discuss issues of ascertainment and selection bias because Dr. Lerner and colleagues presented two different groups, and seemed, from comments in the article, to glean conclusions from the comparison of these groups. In such an instance, issues regarding types of bias are indeed relevant in terms of understanding the validity of the conclusions. Dr. Lerner’s response continues to emphasize the importance of a comparison group. He notes that, “by 4 minutes into a shoulder dystocia, all of the neonates in uncomplicated cases of shoulder dystocia had been born.” This only provides insight if one also knows that there was a complicated group in which this was not the case. For example, if complicated cases also were likely to be delivered by 4 minutes, the “significance” of the finding in uncomplicated cases may not be so significant at all. Therefore, I continue to believe that the issues I raised regarding the construction and comparison of the two groups are not only relevant, but seminal to interpretation of the conclusions.
“How to repair bladder injury at the time of cesarean delivery”
ROBERT L. BARBIERI, MD (EDITORIAL; DECEMBER 2011)
Running suture at the bladder dome may be problematic
As usual, I enjoyed Dr. Barbieri’s editorial. I have a nit to pick, however.
In surgical step 2, Dr. Barbieri recommends the use of running sutures and two-layer closure. When Dr. Alan Perlmutter was the urologic consultant at the old Free Hospital in Boston, a number of “successful” bladder repairs were performed by the ObGyn staff, leaving the patients with symptomatic scarring in the bladder dome secondary to the bunching and puckering that running suture produces in that anatomic site.
Dr. Perlmutter’s teaching point: The repaired bladder dome must be as flexible and expansive as it was before the cystotomy. To this end, he recommended a single, full-thickness layer of neat, interrupted 3-0 plain suture to oppose the edges of the incision. I have used this technique ever since without any complications.
Robert L. Shirley, MD
Winchester, Mass
Methylene blue may be better than sterile milk to assess the bladder
I enjoyed Dr. Barbieri’s editorial, but I would recommend that the surgeon forget the sterile milk and use, instead, 100 cc of normal saline with 10 cc of methylene blue, filling the bladder retrograde to ensure that there are no other leaks. I leave a catheter in place for 2 weeks and give prophylactic antibiotics.
Vincent Culotta, MD
New Orleans, La
More tips for repair of bladder injury
A 5-cm laceration at the dome of the bladder allows visualization of the ureteral openings to ensure that two-layer closure with absorbable suture can be performed safely. I also leave a Foley catheter in place for 7 days, with computed tomography or magnetic resonance imaging generally unnecessary before removal.
Robert F. Porges, MD
New York, NY