1) Dilatation of the cervix:
The cervix must be dilated in order to enter the hysteroscope into
the uterine cavity. Most resectoscopes have an outer sheath diameter
of about 9 mm so that cervical dilatation using mechanical dilators
must be at least this amount. It is optimal to avoid overdilatation
of the cervix since leakage of the distending media through the cervix
and around the hysteroscope (especially under pressures of about 150
mm Hg) then becomes possible.
Some cervical canals are difficult to negotiate with dilators. Different
dilators have a variable amount of curvature to chose from. It is possible
to perforate the lower uterine segments during dilatation. Clinical
situations in which perforation is more common include dilatation of
the pregnant uterus, fibroid uterus, uterus of a women exposed to DES
in utero, uterus after exposure to prostaglandins for cervical ripening,
and infected uterus. Many cases of perforation occur at the onset of
dilatation and the subsequent dilators then continue to open the perforation
Occasionally, a rent in the lower uterine segment occurs during dilatation.
It is thought that rapid dilatation or a difficult dilatation involving
a stenotic inflexible cervix may enhance the frequency of these tears.
It is possible for a tremendous amount of distending media to become
intravasated through these rents and into the large vessels of the lower
uterine region if they are transected.
Cervical incompetence following hysteroscopic surgery is rarely reported
but theoretically possible. The cervix is composed of a tough fibroconnective
tissue and smooth muscle. Closure of the internal os of the cervix is
the general rule even following manual dilatation of up to 15 mm.
The pressure maintained in the uterine cavity may (but generally should
not) exceed both the venous and the arterial pressures so that active
blood flow from transected vessels may not become apparent until the
uterus is deflated. At lesser pressures, bleeding can be identified
and usually controlled. If there is excessive bleeding following destructive
procedures such as endometrial ablation then this is frequently controlled
by tamponade using an inflated foley catheter balloon (10-30 mL for
up to 16 hours) in the uterus. Sometimes the excessive flow can be controlled
with estrogen hormonal therapy (if due to denuding the lining).
3) Excessive intravasation of distending media or CO2 gas:
Whenever vessels are transected during hysteroscopic surgery and either
fluid or gas is entered into the uterine cavity under pressure there
is a possibility of intravasation (entry of these substances into the
circulation). For a more complete discussion of characteristics of the
different available distending media and a sample operating room protocol
see "The Surgeon's Routine" subsection.
I use D5W (5% Dextrose in Water) almost exclusively for my resectoscopic
surgery. Major complications with this solution are very rare. In fact,
there are no reports in the world literature of major morbidity or mortality
with the use of D5W at hysteroscopy. Possible complications include
water intoxication (a reduction in serum osmolality) with a dilutional
reduction in sodium concentration, volume overload (when the circulating
volume in the vascular system exceeds the ability of the heart to adequately
pump this volume and the excess fluid typically begins to collect in
the tissues of the lungs), hypothermia (significant reduction in body
temperature) if room temperature solutions are used without warming
the patient with devices like a "Bair Hugger," and hyperglycemia
(significant excess in circulating glucose concentration that may not
be rapidly metabolized if the patient has insulin resistance or diabetes
The major complication that most hysteroscopic surgeon's focus on
avoiding is water intoxication. The risk of water intoxication from
D5W in a healthy woman with normal renal function is very low, since
the kidneys can typically produce in excess of 1000cc of dilute urine
in response to a decrease in serum osmolarity.
Following hysteroscopic surgery, there is a chance of adhesion (scar)
formation. When I use significant electrocoagulation within the uterine
cavity I provide the infertility patient with intraoperative estrogen
IV (25 or 50 mg of Premarin) and at least a 30 day course of higher
dose Premarin postoperatively (1.25 mg or preferably 2.5 mg if tolerated).
5) Burn injury to the bowel:
When resectoscopic electrosurgery is performed in the area of the
uterine ostia (near the entry site of the fallopian tubes) there is
a chance of thermal injury to adjacent tissue outside the uterine cavity.
This is because the uterine wall in these regions is very thin and heat
from the cautery can travel through the uterine wall and burn adjacent
Endometritis is uncommon after operative hysteroscopy and antibiotics
are usually not "routinely" given. I however have a very low
threshold for the decision to use antibiotics since their potential
benefits outweigh their risks when exposure to infection occurs.