Syringing and probing of the lacrimal system is used to diagnose the site of any nasolacrimal duct obstruction. Nasendoscopy prior to ELDCR is advisable to ensure adequate access and rule out co-existing pathology.
Patients with epiphora may have one or more sites of obstruction along the lacrimal drainage pathway. Proximal obstruction needs to be excluded before listing a patient for ELDCR and this can be performed without the need for complex investigations in the majority of cases. It is also important to exclude malignancy, which may present with blood stained epiphora, or a progressively enlarging mass within the lacrimal sac with or without tethering of the skin. A thorough ophthalmic and nasal examination usually fails to show any obvious etiological factor in the majority of cases.
A history of trauma to the nasoethmoid complex, such as a LeFort type-II or type-III fracture, may result in an unfavorable outcome from EDCR. Such cases are best dealt with via an external DCR where wide excision of bone and mucosa can be undertaken under direct vision.
A visible and palpable swelling, infero-lateral to the medial canthus, may indicate the presence of a lacrimal mucocele or pyocele. Massaging of the lacrimal sac may express discharge or frank pus from the puncti, indicating a diagnosis of mucoid or purulent dacryocystitis.
The patency of the system is tested by flushing with saline solution. Flushing should be undertaken gently since it can cause damage to the delicate cana-liculi and produce false passages. Syringing and probing is done via the upper canaliculus with one of the following results:
nation of the punctum may show it to be extremely small. If the lower canaliculus is stenosed, a DCR is of little value as 90% of tears drain via this route. Probing the lacrimal pathway with a smooth double-ended Bowman's probe often has a "soft stop" as the probe passes through the common canaliculus (Fig. 7.2). In some cases, probing and dilatation may be successful in re-establishing the patency of the system or with a stenosed punctum the ophthalmologist may do a "three-snip procedure" to enlarge the opening.
3. Regurgitation of fluid on syringing through the upper punctum = distal blockage
If saline regurgitates through the lower punctum after a slight delay, then it must have entered the lacrimal sac, encountered a distal obstruction, and returned through the upper canaliculus. The positive regurgitation test thus confirms an obstruction in the nasolacrimal duct. Rarely, a minor degree of blockage of the nasolacrimal duct may resolve with flushing.
Some cases present with both proximal as well as distal obstruction. When the proximal obstruction is
Fig. 7.2. Lacrimal probing of the inferior canaliculus just before passing it through the common canaliculus where a "soft stop" is felt
1. No obstruction = functional problem. In the absence of obstruction, the saline passes down the system into the nose and the oropharynx where a salty taste is experienced. The epiphora may be due to a malposition, where the punc-tum is not in contact with the conjunctiva of the eyelid, or an inadequate lacrimal pump. Scintigraphy may help confirm the diagnosis.
2. An inability to enter the punctum or cannalic-ulus = proximal blockage. This can be due to a stenosed punctum, canaliculi, or both. Exami solely due to a stenosed punctum, a simultaneous three-snip procedure forms an integral part of the ELDCR. The endonasal DCR is inadvisable in concurrent significant proximal obstruction, since the results are invariably disappointing.
Endoscopic examination of the nasal passage is performed to ensure adequate access to the operation site by excluding, among others, a markedly deviated nasal septum, nasal polyposis, chronic rhinosinusitis, and neoplastic lesions. If any nasal conditions are found, then a preliminary or concurrent management of such conditions is planned with the proposed DCR. Surgery is contraindicated in active Wegener's granu-lomatosis.
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