Proximal tubal occlusion involves a blockage at the junction of
the uterus and the tube. The diameter of the fallopian tube is
quite small within the uterine wall. The tube increases in diameter
as you move distally towards the opening near the ovary. The "spasm"
of uterine muscles during the HSG may constrict or occlude one
or both of the fallopian tubes. Small plugs of material, usually
thought to be mucus or proteinaceous debris, can also occlude
the proximal tube(s) where it is very narrow within the uterus.
Permanent proximal tubal damage due to scarring inside the tube
If there is occlusion of only one of the tubes proximally (at
the junction of the uterus), then the patient and infertility
specialist have a difficult decision.
The improvement in fertility seen when there are 2 patent (open)
tubes versus only 1 patent tube with a nonfilling other side has
not been extensively studied but appears to be small (when examined
in one report involving a small number of patients the fertility
rates were 58% versus 50%). This result implies that the second
tube is nonfilling either due to a transient process such as spasm
or due to a significant difference in resistance to flow between
the sides (the diameter of the opening on the filling side may
be slightly greater). In either of these situations the media
travels preferentially through the path of least resistance and
no longterm pathology is present.
Pathology exists when the nonfilling side is occluded with a mucus
or proteinaceous plug. If this is the case, the plug can often
be removed relatively easily with a nonsurgical procedure similar
to the HSG during which the physician (usually a radiologist or
infertility specialist) passes a small catheter (tube) into the
uterine cavity to the tubal ostia (opening) and mechanically flushes
the plug out of the way with dye or dislodges the plug with the
catheter. This procedure, called proximal tubal catheterization,
is usually successful at opening the plugged tube about 60-80%
of the time.
The nonfilling tube may also be occluded by a pelvic process that
should be addressed surgically. If there are severe pelvic adhesions,
endometriosis, or tubal luminal adhesions following a pelvic infection
then the tube may be occluded all the way back to its origin at
the uterus. Such extensive disease is only likely to occur in
patients with a suggestive history. However, there certainly are
some (uncommon) situations where the HSG finding of one occluded
tube is the initial indication of more extensive disease.
The patient's history (including prior infections in the pelvis,
abdominal or pelvic surgery, IUD use) and the couple's comfort
level concerning the risks and benefits of each of these alternative
diagnostic and treatment plans should be used to guide the decisions
that must be made. The primary downside of trying to conceive
for 3-6 months despite one nonfilling tube is that you may delay
other appropriate care. In a young couple this may be acceptable.
In a couple where the woman is in her late 30s or 40s one could
consider a more aggressive approach.