The prevention of adhesion (scar) formation should be a primary goal
of all fertility surgery. Efforts can (and should) be undertaken to
reduce postoperative adhesion formation partially by using principles
collectively referred to as "microsurgical techniques." When
the infertility surgeon recreates a pelvic organ, opens a previously
blocked fallopian tube, removes abnormal structures from within the
uterine cavity, ablates endometriosis, or lyses existing pelvic adhesions
the restoration of normal anatomy and function often depends on minimizing
scar tissue secondary to the surgery.
The microsurgical techniques that should be employed include
- very gentle tissue handling (pulling, rubbing and poking the delicate
reproductive tissues can result in trauma and adhesion formation),
- meticulous control of bleeding = hemostasis (whole blood
within the pelvis is highly irritating to the peritoneal lining and
the inflammation that results can lead to adhesion formation),
- use of magnification if necessary (for establishing proper tissue
planes during dissection and for determining the degree of reapproximation
accomplished when tissues are placed together)
- careful avoidance of infection (administration of antibiotics to
prevent reactivation of a dormant infection within say the fallopian
tubes, sterile technique in handling the operating instruments)
- maintaining tissue moisture (irrigation is generally better than
sponging, preventing desiccation or drying is important since either
leads to adhesion formation)
- minimal effective coagulation of bleeding sites (over cauterizing
results in ischemia and this may enhance adhesion formation)
- reducing foreign material that is placed intraoperatively (use of
small caliber suture material reduces overall bulk, rinsing sterile
gloves or similar objects placed intraabdominally removes talc)
- reducing lateral thermal damage of tissue (lasers, especially ultrapulse
and superpulse CO2 lasers, allow application of very high power densities
to tissues to accomplish ablation by vaporization with little lateral
thermal damage. This is theoretically of great significance)
In theory (although not proven in the existing literature) laparoscopy
has an advantage over laparotomy in terms of adhesion formation. With
laparoscopy, small abdominal incisions are made and ports maintain access
while occluding the holes when no instruments are actively being used.
When compared to laparotomy, this should result in less infection (since
the sites are not open for the duration of the case), less tissue drying
(especially for longer duration cases when drying can be tremendous
for open laparotomies), and less tissue trauma secondary to rubbing
or moving intraabdominal structures with surgical gloves. Additionally,
the laparoscope is able to be placed immediately adjacent to the operative
site to enhance visualization of structures that are buried in the pelvis
and the laparoscope can magnify tissues slightly. The magnification
achieved with the laparoscope is proportional to the distance of the
lens from the tissue viewed, such that at a distance of 1 cm from tissue
the laparoscope typically magnifies the tissue about 6 fold, at 2 cm
about 4 fold, at 3 cm about 2 fold, at 4 cm there is no magnification
and at distances greater than 4 cm there is a reduction in size of the
viewed tissue.
Adjuvants are materials that can be used to help prevent adhesion
formation. The two primary classes of adjuvants include mechanical barriers
and surgical adjuvants.
Mechanical barriers include Gore-Tex surgical membranes (that must
be sewn into position), Interceed TC-7 (a material placed over raw surfaces),
and 32% Dextran 70 (a highly concentrated sugar like solution made up
of high molecular weight glucose polymers that draws in water to act
as a mechanical barrier between structures).
Of these barriers, Interceed seems to be the most commonly used. Literature
from several clinical reports support a role for Interceed in adhesion
prevention.
32% Dextran 70 (Hyskon) has been popular in the past and is still
in use in some centers. Mechanical separation of raw surfaces is associated
with the water drawn into the concentrated solution (hydroflotation)
and a siliconizing effect (the solution is slick). When 200 cc of 32%
Dextran is placed intraperitioneally there is usually some ascites for
up to a week, and patients occasionally complain of fluid leaking from
the incision sites, labial swelling, bloating and weight gain.
Surgical adjuvants include antiinflammatory drugs, anticoagulants,
prophylactic antibiotics, calcium channel blockers and plasminogen activators.
The antiinflammatory drugs include corticosteroids (intended to decrease
vascular permeability and enhance lysosomal stabilization, each of which
should limit adhesion formation), antihistamines (intended to decrease
vascular permeability and decrease fibroblast proliferation, each of
which should limit adhesion formation), and nonsteroidal antiinflammatory
agents like motrin (reduces prostaglandin formation to limit adhesion
formation). None of these agents has been shown to be beneficial in
terms of adhesion formation in large clinical trials but they are often
used by physicians whose personal experience with the medications has
been favorable. I do not use these agents at this time.
Anticoagulants include low dose heparin (about 1-5 units/mL) within
irrigation solutions. High doses of heparin should not be used because
there is an increased chance of hemorrhagic surgical complications.
Low dose heparin has not been shown to be of benefit in terms of adhesion
formation in clinical trials.
Antibiotics may reduce the incidence of infection when given prophylactically.
The goal is to achieve adequate doses at the tissue sites during the
surgery. Vibramycin is often used for tubal surgery since it effectively
treats Chlamydia. Many of the higher generation cephalosporins also
work well for gynecological pelvic surgery. I typically use cefotetan
or mefoxin (depending on availability).
Calcium channel blockers have been used in hamsters with good results,
but human studies are lacking. In theory, these agents decrease tissue
ischemia, limit prostaglandins, reduce platelet aggregation, and limit
vasoconstriction. The use of these agents is awaiting appropriate human
trials.
Plasminogen activators accelerate fibrinolysis to reduce the bulk
of fibrin clots. Use of these agents is also awaiting appropriate human
clinical trials.
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