Review for 10.1186/1471-230X-12-19 (2012)

Reviewer's report
Title:Fully covered self-expandable metal stents (SEMS), partially covered
SEMS and self-expandable plastic stents for the treatment of benign esophageal
ruptures and anastomotic leaks
Version: 2Date:14 December 2011
Reviewer: Bas P Wijnhoven
Reviewer's report:
The study by van Boeckel et al. reports on the outcome of a series of stent
placements for benign oesophageal injuries or anastomotic leaks. Clinical succes
was judged to be 76% without differences between three gorups of stents used.
1. The study is well written, clear and concise. The authors are all from
well-respected GI units. However, the inherent methodological problems with this
study as well as many other case series are numerous:
retrospective analysis
three centers involved (2 from the Netherlands and one from the USA)
very different etiologies of esophageal injury-rupture
timing between onset of injury and treatment-stent placement unknown
no information on the number of patients with similar esophageal ruptures and
leaks who did not undergo stent placement in the three centers during the study
period (what is the denominator for the study period??)
hence, highly selective indications for stent placement in these patients that
remain obscure for the reader
comparison with surgical series impossible due to lack of information on grade,
severity and extent of contamination, size of rupture, locatioon of rupture etc. etc.
2. The comparison of the efficacy of three different stent types is not valid. There
were no differences between the three stent types but the indication and reasons
to prefer one above the other in this series is unclear. Moreover te number of
patients per group is small. Given the heterogeneous patient population and
underlying disorders in the groups no comment or conclusion whatsoever can be
made.
3. The authors indeed make a valid comment on the importance of adequate
drainange of sepsis at and around the site of oesophageal injury. This is the most
important aspect of treatment of esophageal rupture and anastomotic leaks. The
questions still remains if stent placement at all truly does aid or on the
(spontaneous) healing of oesophageal leaks. Several surgical approaches with
T-tube placement with surgical drainage or external drainage alone is succesful
have been published. Does a stent truly favourably alter the course of the
disease? That is the question that has not been answered so far. Therefore the
efficacy of stent placement in healing benign esophageal leaks and perforations
can not really be commented on.
4. Can the authors comment on the time between onset of oesophageal
trauma/rupture and stent placement? This is an important determinant of succes
with surgery as well as stent placement. The same is true for the extent of
collateral damage/contamination of the mediastinum-pleural cavity. In line with
other reports that stent placement in the acute setting directly after occurrence of
oesophageal rupture is succesful because of less contamination. E.g. 9 patients
had a rupture after pneumatic dilatation that likely was diagnosed at the time of
the endoscopic treatment. These patients likely benefited from a stent. Whereas
the patients with Boerhaave syndrome (n=4) likely were diagnosed at a later
stage (12-24 hrs??). Hence stent placement might have been less effective. Can
the authors gove details on the success rate for the different underlying
pathofysiology/diseases? This is crucial for interpretation of the results.
The conclusion of the study that covered stents are effective and safe should be
weakened and more in balance with the reported complications. The safety with
two ruptures upon removal of the stent, two patients with bleeding including one
stent reated death should not be forgotten about. Furthermore, stent migration
remains a big problem, as shown in this study. Lastly, one patient needed an
operation to remove the stent.
6. The chosen (primary) endpoint of the study was sealing of rupture or leak
confirmed by endoscopy. This can since the accuracy of endoscopy to determine
complete sealing is by far not 100%. Ideally, a combination of an
esophagogram/CT with oral contrast and endoscopy would probably have been
better.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.