Endoscopic Transnal Surgery For Lacrimal Obstruction:

Mohammed Mohammed El Hamshary

Numerous theories exist to explain tear transport which indicate thecomplexity of the mechanism. No one concept is entirely satisfactory.Various opinions exist to explain which part or parts of the tear conductingchannels and which phase of lid movements are most essential for theconveyance of tears. One concept is that the tear sac is compressed on lidclosure leading to its evacuation, and on lid opening the sac expands and thetears are sucked into the canaliculi. The opposite view to this is thatcontraction of the orbicularis expands the tear sac, and sucking tears.Relaxation of the muscle leads to elastic contraction of the lacrimal sac, andits evacuation.This study comprised fifty-eight cases (eighty-six sides) that attendedto the Ophthalmologic and/or Otolaryngologic out-patient’s clinics at KasrEl-Aini, and/or Madinet Nasr Hospitals during the period from November1993 to May 1996. They were divided into four groups; healthy, diseased(epiphoric), endoscopic DCR, and external DCR groups. The endoscopicDCR group included small and large fistula procedure, and the externalDCR group comprised those with or without silicone rod tubing.In this study pressure changes within the lacrimal sac were recorded inthe four groups during blinking, forced blinking, nasal respiration, side toside eye movement, and Valsalva’ s maneuver. This was done by means of ametal cannula inserted into the lacrimal sac and the pressure tracings wererecorded by a transducer-amplifier-recorder system.In healthy individuals, air bubbles and saline reflux from the noncannulatedpunctum 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. Onthe 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 anegative pressure in all healthy cases, which indicates lacrimal sacexpansion during lid closure. On the other hand, all diseased casesdisplayeda positive pressure which indicates nasolacrimal duct obstruction. Duringnasal respiration, and side to side eye movement in both healthy anddiseased cases, the lacrimal sac displayed negative and positive pressurechanges without any persistent configuration. During Valsalva’s maneuverthe lacrimal sac pressure in both groups was not affected most probably dueto the presence of valve of Hasner in healthy individuals, and obstruction ofnasolacrimal duct in the diseased cases.Three causes of lacrimal sac obstruction were met in this study:dacryocystitis, congenital nasolacrimal duct obstruction, and facial traumaaffecting the nasolacrimal duct. nCR operation was performed to connectthe lacrimal sac directly to the nasal cavity to bypass obstruction in the sacor in the nasolacrimal duct.In successful endoscopic and/or external operations, injection of salinein the lacrimal sac, gave the same picture of the healthy individuals due to.the presence of a patent fistula. They displayed negative lacrimal sacpressure during blinking and forced blinking, but it was less in amount thanthat of healthy cases due to the presence of patent fistula. In contrast tohealthy measures, the pressure was positive during Valsalva’s maneuverbecause the fistula transmitted the high nasal pressure to the sac. It wasnoticed that the pressure was highly positive in successful externalnCRthan that of endoscopic nCR due to the very wide fistula in the former. Thiswide fistula was also the cause of recurrent dacryocystitis as it may facilitateascending infection from the nose.Failed endoscopic and/or external DCR operations presented withmucoid, mucopurulent or purulent reflux from the non-cannulated punctum,and lacrimal sac swelling during saline injection. Delayed or absence salinetaste, and delayed, or failure of pressure to descent depended on thepresence of partial or complete obstruction of the fistula after operation.Moreover, a positive pressure was displayed during blinking and forcedblinking. In contrast to the diseased cases, a positive pressure was noticedduring Valsalva’s maneuver, which may be due to presence of partialobstruction, 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 6month, which was enough to prevent wound contracture. Immediate postoperativeepiphora usually due to canalicular swelling from the passage ofthe tube. In successful cases this epiphora usually disappeared after a periodof one week up to 3 months.Dacryocystitis and nasal infection affected the results, so medicaltreatment of dacryocystitis, and nasal hygiene were recommended.It was concluded that, during lacrimal sac irrigation, the sac does notswell in normal and successful DCR, and the subject tastes slain rapidly inhis mouth, but swelling in the medial canthal area was noticed in patientswith epiphora due to nasolacrimal duct obstruction and failed operationswith discharge from the non-cannulated punctum, and the patient does nottaste saline at all or may tastes it after some delay. The lacrimal sac pressuretends to be negative during blinking and forced blinking in normal healthysubjects and successful endoscopic or external DCR operations, denotingexpansion of the sac during both these actions. Positive lacrimal sac pressurewas observed in diseased (epiphoric) subjects and failed endoscopic orexternal DCR operations. Valsalva’s maneuver has no effect on the sacpressure in healthy and diseased subjects, but increases the pressure afterDCR operation either endoscopic or external, unless complete reobstructionof the of the fistula will occurred, in which no change will occur. There is nosatisfactory impression about the sac pressure during nasal respiration andside to side eye movements. The endoscopic DCR approach had severaladvantage over the external approach in this study as it was less traumatic,avoided facial wound and scar, the attachment of orbicularis oculi to theI lacrimal sac not disturbed that preserved the pump action, lacrimal sac wasaccessed d~ectly avoiding double-side dissection of the sac, and possibilityof ascending infection was less. There was no significant difference in thesuccess rate between large and small fistula in endoscopic DCR.Farther studies are recommended about: the effect of eye movementand nasal respiration on the lacrimal sac pressure, longer period of followup, randomized selection of external and endoscopic DCR, the differencebetween small and wide fistula endoscopic DCR, and the effect of widefistula on tear elimination, and ascending infection.