الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Numerous theories exist to explain tear transport which indicate the
complexity of the mechanism. No one concept is entirely satisfactory.
Various opinions exist to explain which part or parts of the tear conducting
channels and which phase of lid movements are most essential for the
conveyance of tears. One concept is that the tear sac is compressed on lid
closure leading to its evacuation, and on lid opening the sac expands and the
tears are sucked into the canaliculi. The opposite view to this is that
contraction of the orbicularis expands the tear sac, and sucking tears.
Relaxation of the muscle leads to elastic contraction of the lacrimal sac, and
its evacuation.
This study comprised fifty-eight cases (eighty-six sides) that attended
to the Ophthalmologic and/or Otolaryngologic out-patient’s clinics at Kasr
El-Aini, and/or Madinet Nasr Hospitals during the period from November
1993 to May 1996. They were divided into four groups; healthy, diseased
(epiphoric), endoscopic DCR, and external DCR groups. The endoscopic
DCR group included small and large fistula procedure, and the external
DCR group comprised those with or without silicone rod tubing.
In this study pressure changes within the lacrimal sac were recorded in
the four groups during blinking, forced blinking, nasal respiration, side to
side eye movement, and Valsalva’ s maneuver. This was done by means of a
metal cannula inserted into the lacrimal sac and the pressure tracings were
recorded by a transducer-amplifier-recorder system.
In healthy individuals, air bubbles and saline reflux from the noncannulated
punctum were noticed after saline injection into the lacrimal sac.
There was no sac swelling and saline was immediately tasted in the mouth.
The pressure in the sac rapidly increased, then rapidly returned to zero. On
the other hand in the diseased subjects there were a purulent or mucopurulent reflux from the noncannulated punctum, swelling of the sac,
no saline taste, and a persistent pressure increase that failed to decrease.
Lacrimal sac pressure during blinking and forced blinking displayed a
negative pressure in all healthy cases, which indicates lacrimal sac
expansion during lid closure. On the other hand, all diseased casesdisplayed
a positive pressure which indicates nasolacrimal duct obstruction. During
nasal respiration, and side to side eye movement in both healthy and
diseased cases, the lacrimal sac displayed negative and positive pressure
changes without any persistent configuration. During Valsalva’s maneuver
the lacrimal sac pressure in both groups was not affected most probably due
to the presence of valve of Hasner in healthy individuals, and obstruction of
nasolacrimal duct in the diseased cases.
Three causes of lacrimal sac obstruction were met in this study:
dacryocystitis, congenital nasolacrimal duct obstruction, and facial trauma
affecting the nasolacrimal duct. nCR operation was performed to connect
the lacrimal sac directly to the nasal cavity to bypass obstruction in the sac
or in the nasolacrimal duct.
In successful endoscopic and/or external operations, injection of saline
in the lacrimal sac, gave the same picture of the healthy individuals due to.
the presence of a patent fistula. They displayed negative lacrimal sac
pressure during blinking and forced blinking, but it was less in amount than
that of healthy cases due to the presence of patent fistula. In contrast to
healthy measures, the pressure was positive during Valsalva’s maneuver
because the fistula transmitted the high nasal pressure to the sac. It was
noticed that the pressure was highly positive in successful externalnCR
than that of endoscopic nCR due to the very wide fistula in the former. This
wide fistula was also the cause of recurrent dacryocystitis as it may facilitate
ascending infection from the nose.
Failed endoscopic and/or external DCR operations presented with
mucoid, mucopurulent or purulent reflux from the non-cannulated punctum,
and lacrimal sac swelling during saline injection. Delayed or absence saline
taste, and delayed, or failure of pressure to descent depended on the
presence of partial or complete obstruction of the fistula after operation.
Moreover, a positive pressure was displayed during blinking and forced
blinking. In contrast to the diseased cases, a positive pressure was noticed
during Valsalva’s maneuver, which may be due to presence of partial
obstruction, or a complete obstruction of the fistula by a membrane.
There was no apparent relation between the size of the created fistula
(small or wide) and the success rate in cases of endoscopic DCR.
The silicone tube of endoscopic DCR was removed after a period of 6
month, which was enough to prevent wound contracture. Immediate postoperative
epiphora usually due to canalicular swelling from the passage of
the tube. In successful cases this epiphora usually disappeared after a period
of one week up to 3 months.
Dacryocystitis and nasal infection affected the results, so medical
treatment of dacryocystitis, and nasal hygiene were recommended.
It was concluded that, during lacrimal sac irrigation, the sac does not
swell in normal and successful DCR, and the subject tastes slain rapidly in
his mouth, but swelling in the medial canthal area was noticed in patients
with epiphora due to nasolacrimal duct obstruction and failed operations
with discharge from the non-cannulated punctum, and the patient does not
taste saline at all or may tastes it after some delay. The lacrimal sac pressure
tends to be negative during blinking and forced blinking in normal healthy
subjects and successful endoscopic or external DCR operations, denoting
expansion of the sac during both these actions. Positive lacrimal sac pressure
was observed in diseased (epiphoric) subjects and failed endoscopic or
external DCR operations. Valsalva’s maneuver has no effect on the sac
pressure in healthy and diseased subjects, but increases the pressure after
DCR operation either endoscopic or external, unless complete reobstruction
of the of the fistula will occurred, in which no change will occur. There is no
satisfactory impression about the sac pressure during nasal respiration and
side to side eye movements. The endoscopic DCR approach had several
advantage over the external approach in this study as it was less traumatic,
avoided facial wound and scar, the attachment of orbicularis oculi to the
I lacrimal sac not disturbed that preserved the pump action, lacrimal sac was
accessed d~ectly avoiding double-side dissection of the sac, and possibility
of ascending infection was less. There was no significant difference in the
success rate between large and small fistula in endoscopic DCR.
Farther studies are recommended about: the effect of eye movement
and nasal respiration on the lacrimal sac pressure, longer period of follow
up, randomized selection of external and endoscopic DCR, the difference
between small and wide fistula endoscopic DCR, and the effect of wide
fistula on tear elimination, and ascending infection.