Review for 10.1186/s12876-022-02346-2 (2022)

Title: Management of esophageal perforations in infants by endoscopic vacuum therapy – a
single center case series
Version: 1 Date: 17 Feb 2022
Reviewer:  Gunnar Loske
Reviewer's report:
Review
Management of esophageal perforations in infants by endoscopic vacuum-assisted closure
therapy
Dominik J. Kaczmarek et al.
The paper is one of the first publications on the use of endoscopic negative pressure therapy in
very young infants. To the best of my knowledge, this is the first paper in which a new small
typ of open pore film drain was used for endoscopic vacuum therapy for esophageal leaks in
children. It is the first paper ever demonstrating the use of this type of drain in children.
The drain consists of a very thin open-pore membrane and a tube. Negative pressure can be
delivered to an internal wound by means of an electronic pump. The drain has the advantage of
being very small in diameter and to be manufactured in any length.
The retrospective paper is carefully designed.
I strongly recommend accepting it after revision.
I still have a few comments that I ask to be edited.
Title:
I suggest to change: Management of esophageal perforations in infants by endoscopic vacuum
therapy, since the term "vacuum assisted closure" "V.A.C." is a trademarked term of KCI-
Company.
I suggest to change the whole manuscript and abstract according to the suggestion. Thank you.
Abstract (page 2)
Line 14 "Vacuum drainage film" please change to “open-pore drainage film”.
Line 15 foam/sponge is duplicated. Use open-pore polyurethane foam or polyurethane sponge.
Line 17 “endoscopically placed into the esophagus” please add: (intraluminal EVT)
Line 20/21 Instead of mean value, median would be the better statistical value given the small
number of cases. See also Data presentation.
Keywords
I suggest to delete “endo-sponge”, since “Endosponge” is a protected term of B.Braun, Aesculap.
If you like, you could add “endoscopic negative pressure therapy”.
Background
Good summary and description of the problem.
Methods (page 6)
Line 11/12 "Vacuum drainage film" please change to “open-pore drainage film”. The correct
name of the membrane is: Suprasorb CNP drainage film, please correct.
Line 13 use foam or sponge, not both.
Line 25 (intraluminal EVT) please add Ref:[10].
The following reference would also fit well, as this series reports on intraluminal EVT for
iatrogenic perforations, which three of the patients also had. [Loske G, Schorsch T, Dahm C,
Martens E, Müller C. Iatrogenic perforation of esophagus successfully treated with Endoscopic
Vacuum Therapy (EVT). Endosc Int Open. 2015 Dec;3(6):E547-51.]
Please also briefly describe the underlying principle of action of endoscopic vacuum therapy.
This should be included. It is to be expected that the work will also be read by pediatric
colleagues who are not yet familiar with the method of EVT.
For the same reason, the essential technical information about the different drains should also
be added [Ref 10]. A current other suitable publication would be: Gutschow CA, Schlag C,
Vetter D. Endoscopic vacuum therapy in the upper gastrointestinal tract: when and how to use
it. Langenbecks Arch Surg. 2022 Jan 18. doi: 10.1007/s00423-022-02436-5.
As correctly discussed, the current medical products are after all not suitable for children and
must be manufactured by the endoscopist. Especially important in intraluminal EVT: length of
the drainage element to cover the leakage completely and the small diameter.
Results (Page 8)
Very good and interesting presentation of the patient characteristics.
Page 9
The adaptation of the insertion technique for smallest lumina with film EVT and fluoroscopically
by wire guide is very impressive. (Include in Discussion!).
Please add some descriptions of the visible effects of negative pressure therapy on the tissue.
In adults, with film EVT, one sees aspiration nubs the epithelium, as evidence of the therapy
working. In the figures these effects a visible and should be described.
Did the authors notice any permanent damage or changes on the esophageal ephithelium, or
were the visible suction changes completely reversible? After what period of time?
In adults, the sponge drains can adhere very tightly, have the authors observed this as well?
Intraluminal open-pore drains can become non-functional due to blockage caused by swallowing
mucus. This is also a reason to change them regularly. Have authors  observed this?
Discussion
Good discussion.
I would like to provide a suggestion for discussion that the authors may be able to include
to the discussion part. From my experience with adults, I can say that the draining materials
(sponge and film) differ in some key properties. The sponge adheres much more strongly to
the tissue and has higher debriding properties. It is more suitable for inducing granulation and
eliminating necrosis. Therefore, it is consistent to use the sponge EVT in children 1 and 2.
In children 3 and 4, the typical finding is an fresh iatrogenic perforation without infection or
necrosis. These can also be treated with a film EVT alone. A  reference  is: Loske G, Scharsack E,
Gobrecht O. Emergency endoscopic negative pressure therapy of a long oesophageal perforation
in eosinophilic esophagitis with a single-lumen nasogastric tube-like open-pore film drain.
Endoscopy. 2021 Jun 8. doi: 10.1055/a-1493-1805.
In Pat 2 it can be discussed whether the stenosis is due to the EVT or whether it is a consequence
of the inflammation and ischemia/necrosis at the insufficient anastomosis. To my experience it
is the ischaemia which is responsible.
The authors used both sponges and film drains. Where do they see the differences and the
advantages and disadvantages? What was the reason to start with film drains in all patients?
It should still be explicitly included that the technical advancement of the open pore film drains
(small diameter, any length of drainage element), makes it possible or easier to use intraluminal
negative pressure therapy even in the very young children.
The authors can highlight that this is the first paper where the open pore film drain was used
as a drain for endoscopic negative pressure therapy for esophageal leaks in children. To my
knowledge, it is the first work ever in which this type of drainage was used in children.
The authors  describe a new placement technique of film drain for very small lumens. To my
knowledge, the technique is not pre-described in this way. They can emphasize that When do
the authors suggest to do the placement in this technique, or better under endoscopic view?
Nutrition is an important issue. Doublelumen film drains have been developed that allow
simultaneous feeding. If the authors find the reference appropriate, they could mention this
and include the following references: L oske G, Müller J, Schulze W, Riefel B, Müller CT.
Pre-emptive active drainage of reflux (PARD) in Ivor-Lewis oesophagectomy with negative
pressure and simultaneous enteral nutrition using a double-lumen open-pore film drain (dOFD).
Surg Endosc. 2022 Jan 1; Loske, G. Endoscopic negative pressure therapy of the upper
gastrointestinal tract. Surgeon 90, 1-6 (2019). https://doi.org/10.1007/s00104-018-0727-x
Figure 1
Please insert a cm/mm designation from which the diameter and length can be read.
Figure 2
Very interesting series. Please describe not only the tag, but also what can be seen. E.g. an
anastomosis with necrosis, this finding also leads to a stenosis in adults. Here you can also see
very nicely the suction effects through the film, as a sign that a negative pressure has succeeded
on the surface of the tissue.
The images correspond exactly to what can be observed in adults. The (iatrogenic) perforations
are also typical. See commentary to result before.
Tables are informativ.