The
society will be guided by the newly elected board
with four surgeons: Hans Jeekel, president (The
Netherlands), Andre D’Hoore (Belgium), Harry
Van Goor (The Netherlands) and Marc Miserez (Belgium),
and five gynaecologists: Victor Gomel, vice-president
(Canada), Philippe Koninckx, secretary (Belgium),
Gere DiZerega, (USA), Michel Canis, (France) and
Roger Molinas (Paraguay). Meetings will be held
every two years, and the next meeting will be hosted
by Michel Canis in Clermond Ferrand, France in September
2008.
The PAX society has defined its
mission to promote and stimulate basic and clinical
research with a focus on translational research
in order to develop and implement clinical applications.
This is reflected in the composition of the society
and in the program of the meeting, balancing basic
research and clinical research from both abdominal
surgery and gynaecology, with invited lectures from
other innovating areas such as stem cells, angiogenesis
and tissue engineering.
The clinical scope today comprises
postoperative adhesion formation and its prevention,
tumour metastasis and port site metastasis, a phenomenon
of which the pathophysiological similarity with
adhesion formation only recently got into focus
and the biology of meshes which ideally should be
very adherent on one side and not at all at the
other side.
The physiology and the pathology
of the abdominal cavity is clearly established as
a specific micro-environment with repair mechanisms
which are different from the rest of the body. Already
25 years ago we realised that the endocrinology
of the peritoneal cavity was different with steroid
hormone concentrations often 100 to 1000 times higher
than in plasma and with specific time courses during
the menstrual cycle. Today we know that the innervation,
pain sensation, immunology, cytokines and trauma
repair mechanisms are specific and different from
the rest of the body.
Highlights of the VIIth
PAX meeting
The PAX meeting had two general sessions, three
clinical sessions and three sessions devoted to
pathophysiology. Each session consisted of an overview
and specific topics by an expert followed by selected
free communications. The first session introduced
the clinical burden of adhesions with its associated
risks of gastrointestinal complications and re-operation,
its impact upon fertility and pain, and the associated
risks of trocar insertion. Free communications addressed
the dynamic structure of adhesions, pathophysiology
of mesh repair and the associated adhesions in animal
models. A fascinating film of a 1900 nephrectomy
put surgery into perspective!
The second, third and fourth sessions highlighted
the pathophysiology of the peritoneal cavity, with
presentations on the mesothelial cell, the inflammatory
reaction, surfactant, infection, macrophages angiogenesis
and a review on adhesion formation. The deleterious
effects of the pure CO2 pneumoperitoneum, of dessication,
and the beneficial role of lower temperature upon
adhesion formation and upon the mesothelial cell
morphology were comprehensively reviewed.
A series of presentations dealt
with the specific environment of the CO2 pneumoperitoneum
during endoscopic surgery, with its associated effects
of mesothelial hypoxia and ROS production, together
with its prevention by adding a few percent of oxygen
and decreasing temperature. The bottom line is that
following metabolic injury the mesothelial cells
retract thus exposing directly the intercellular
extracellular matrix as beautifully shown by scanning
electron microscopy.
With this mechanism in mind, it
is not surprising that tumour cell implantation
is increased and can be prevented by similar mechanisms
as adhesion formation. Today this was shown for
mesothelial hypoxia and its prevention such as oxygen
and humidification and for the addition of phospholipids
which prevent both adhesion formation and tumour
cell metastasis.
These reviews were followed by
specific presentations dealing with the surgical
trauma, TGFb and fibrinolysis, Reactive oxygen species,
the chronic inflammatory character of adhesions,
and unexpected observations of the preventive character
of morphine.
The fifth session was devoted to
the clinical prevention of adhesion formation and
reviewed the current clinically available products
with proven efficacy such as Adept, Seprafilm, Adhes-X,
Oxyplex and Hyalobarrier. Comparative data are not
available yet and efficacy ranges around 50% prevention.
The sixth session specifically
addressed the pathophysiology of the different types
of meshes and of their coatings and their complications
in gynaecology and in surgery. Although for mesh
erosions no animal model is available, the animal
models are extremely useful to understand the dynamics
of mesh in-growth and strength, another specific
aspect of peritoneal cavity pathophysiology.
The seventh session dealt with
tumour cell implantation and port site metastasis,
a phenomenon which has curtailed the introduction
and widespread use of laparoscopy in oncology. For
the first time a series of presentations highlighted
the similarity of the mechanisms, i.e. mesothelial
cell trauma with exposure of the extracellular matrix,
enhancing adhesion formation and tumour implantation.
Also the similarity in preventing adhesions and
tumour metastasis by phospholipids or by adding
oxygen was striking.
The last session looked
at the future
A new combined approach to adhesion prevention was
presented. Addressing sequentially the different
pathophysiological mechanisms known to be involved,
together with a barrier method, a clinical efficacy
of over 90% can be expected. The impact of robot
surgery on adhesions remained unclear. Fascinating
were the models of tissue engineering and more specifically
the lessons derived from cell engineering in inflammatory
joint disease. The last presentation, from the Boston
group, describing the role of substance P in adhesion
formation, was awarded the prize of the best free
communication, for the quality and the innovative
aspect of the work.
Conclusions
Bringing together researchers, surgeons and gynaecologist
to address the specific problems and the pathophysiology
of the peritoneal cavity has proven again to be
extremely useful to exchange and stimulate ideas.
We trust that the PAX Society will be a useful forum
to address these important clinical problems of
adhesion formation, mesh biology and tumour implantation,
and we look forward to the next meeting in 2008
in Clermont Ferrand.
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