Endoscopic Dacrocystorhinostomy





Endoscopic Dacryocystorhinostomy


Nasolacrimal duct dysfunction, whether by lacrimal pump failure or nasolacrimal obstruction, prevents the flow of tears through the lacrimal system, resulting in epiphora. Dacryocystorhinostomy (DCR) is a commonly performed procedure for cases of nasolacrimal duct dysfunction. The endoscopic approach offers a different view from the originally described endonasal approach in 1893 by Caldwell. After the advent of endoscopes, the endoscopic DCR was described, allowing for better visualization of the endonasal lacrimal anatomy. In 2003, Tsirbas and Wormald described use of mucosal flaps for improved apposition of the lacrimal sac to the nasal mucosa. In this chapter, we discuss our endoscopic approach to DCR in the setting of nasolacrimal duct obstruction (NLDO).


Workup


NLDO can occur for many different reasons and can be divided into primary and secondary obstruction. Primary obstruction occurs as the result of inflammation and fibrosis of unknown causes, whereas secondary obstruction occurs as the result of inflammation, infection, neoplasm, or mechanical obstruction. Regardless of etiology, such patients often present with epiphora. However, the diagnosis can be complicated by the possibility of hyperlacrimation, which is due to an excretory issue in the lacrimal gland instead of an obstruction, as in epiphora. To delineate the difference between these two etiologies, a full history and physical examination, including medication lists, previous operations of the lacrimal system or sinuses (including lacrimal probing), previous injuries or trauma to the face, bloody tears, initial presentation of excessive tearing, and natural history of the complaint should be obtained.


Primary hyperlacrimation is uncommon but can be due to stimulation of the lacrimal gland in lacrimal gland neoplasia or from the use of parasympathetic medications (i.e., pilocarpine). Irritation to the ocular surface can also cause a reflex as the result of stimulation of the trigeminal nerve (e.g., trichiasis, distichiasis, episcleritis, conjunctivitis, iritis, orbital chemosis). In situations of previous facial nerve dysfunction (trauma, Bell palsy, and so on), there is potential for inappropriate reinnervation of the lacrimal gland with nerve fibers originally destined for the salivary gland, leading to gustatory tearing. The treatment of these conditions is not further discussed in this chapter.


Epiphora has many potential causes; therefore a thorough history and physical examination are pertinent. The following text lists subsites of obstruction and their associated causes:




  • Punctal stenosis (complete/partial), which can be caused by malposition or scarring




    • Congenital stenosis, occlusion, infection/radiation, pemphigoid, tumors, and so on




  • Common canalicular stenosis




    • Congenital absence, canaliculitis, tumor compression or infiltration, trauma, after radiation




  • Lacrimal sac stenosis




    • Sac inflammation, prelacrimal fibrosis, dacryolithiasis, primary lacrimal sac neoplasia, adnexal tumor compression




  • Nasolacrimal duct




    • NLDO, delayed opening of the Hassner valve, craniofacial abnormalities, agenesis, tumor, trauma, severe septal deformity




  • Eyelid malposition




    • Ectropion




      • The punctum should not be visible when the patient is recumbent.



      • Snap-back and pinch test can be used for diagnosis.



      • Entropion





  • Pump dysfunction




    • Laxity of the lower eyelid or dysfunction of the orbicularis oculi




Imaging


Imaging is not required in the standard evaluation of epiphora, but in situations when the clinical picture is unclear, they can be used as adjuncts for diagnosis.


Computed Tomography


Computed tomography (CT) can be helpful to determine if there is concomitant sinus disease, as this can be managed at the time of the DCR. CT can also be useful if there is concern for neoplasia arising within the sinus cavity or the nasolacrimal system. However, CT is not required preoperatively in standard cases and in our practice, we only use these in the previously listed situations.


Contrast Dacryocystography


Dacryocystography is used to assess the anatomic features of the lacrimal system and can be combined with plain radiograph or CT. Dacryocystography requires the lacrimal sac to be injected with radiopaque material with follow-up imaging completed at 5 and 30 minutes. This can be used to identify possible locations of anatomic obstruction, including the presence of dacryoliths or diverticuli. However, this is not commonly applied clinically by our team.


Dacryoscintigraphy


Dacryoscintigraphy evaluates physiologic tear drainage; therefore radioactive tracer is administered into the fornix of the conjunctiva. The patient then undergoes a series of sequential images with normal blink responses. These sequential images are captured over a range of up to 10 to 15 minutes, as normal tear transport is variable. This nuclear medicine study can be used to further investigate causes of epiphora in situations of a negative result for the dye disappearance test (DDT). However, our team uses the Jones I and II tests in our clinic instead of the DDT.


Endoscopy Evaluation


All patients undergo a rigid nasal endoscopy as part of the investigation of epiphora. This is used to evaluate for concomitant sinus disease or other pathologies warranting further surgery at the time of the dacryocystorhinostomy (e.g., anatomic abnormality, neoplasia, access for DCR).


Dye Disappearance Test


Sterile 2% fluorescein or a fluorescein strip is instilled into the conjunctival fornix and clearance of the fluorescein is evaluated after 5 minutes. Both eyes should be evaluated with a slit lamp for information regarding tear film as well as puntum assessment. A positive test result is one in which the dye disappears from the conjunctiva. This test result can be weakly positive (i.e., some dye disappearance), which indicates a potential stenosis or pump failure. The DDT can be done in both eyes simultaneously and used for comparison, particularly in cases of unilateral epiphora. This test can be particularly helpful in children, as they are unlikely to tolerate sac washout testing (Jones II) without sedation.


Jones Tests


The Jones I test, also known as the primary dye test, evaluates the flow of the lacrimal system under physiologic conditions. A Jones I test is performed exactly the same as a DDT: 2% fluorescein is instilled in the conjunctival fornix, except endoscopy is used to confirm outflow. Using rigid endoscopy, the inferior meatus and the Hassner valve are then observed for flow of fluorescein through the lacrimal system at 5 minutes. If the result of this test is positive, indicating flow through the system, then no further testing is required. If this test result is negative, then progression to the Jones II test is completed.


In the Jones II test, a 27-gauge syringe with saline solution is placed through the inferior canaliculus for sac washout. At this time, probing is also undertaken with the syringe. If there is flow in the sac washout test, then this is considered a positive test result and the pathology is lacrimal pump dysfunction. Lacrimal pump dysfunction is less likely to have a successful outcome after surgery. Other options may need to be considered as an adjunct to DCR pending the causation of lacrimal pump dysfunction (ectropion, orbicularis dysfunction, and so on). If there is partial regurgitation during the sac washout test, then there is a stenosis of the nasolacrimal duct that is being overcome by the forced manual washout. If there is total regurgitation of the sac washout, then it is important to note the results of the probing completed with the washout syringe. If a hard stop is present (indicating that the probe has gone to the medial orbital wall), then the stenosis is in the nasolacrimal duct. However, if a soft stop is present, this is indicative of scarring in the common canaliculus or obstruction of the tested canaliculus ( Fig. 13.1 ).


Jan 3, 2021 | Posted by in OPHTHALMOLOGY | Comments Off on Endoscopic Dacrocystorhinostomy
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