External Dacryocystorhinostomy

ABSTRACT: Procedure: The surgery shown in this video is an external dacryocystorhinostomy (DCR) surgery with insertion of a nasolacrimal duct stent in a patient with a history of dacryocystitis of rare fungal etiology. Introduction: The purpose of external DCR is to bypass a nasolacrimal duct obstruction and create a new pathway for tears to drain from the canaliculi into the nasal cavity. The surgery involves removal of bone adjacent to the nasolacrimal sac, connecting the lacrimal sac to the nasal mucosa, and generally includes placement of a nasolacrimal stent. Indications/Contraindications: The most common indication for DCR is primary or secondary acquired nasolacrimal duct obstruction (NLDO), which may be due to fibrosis, infection, inflammation, neoplasia, or trauma. Contraindications for this surgery have been noted to include patients with active dacryocystitis with abscess formation and lacrimal system neoplasms. Materials/Methods: Standard external DCR surgical instruments were used. Important steps include expansion of the bony ostium with Kerrison rongeur, insertion of the bicanalicular Crawford stent, and suturing the anterior flap of the lacrimal sac to the anterior flap of nasal mucosa. Results: The patient tolerated the surgery well with improved drainage of the nasolacrimal system. Conclusion: External DCR is an effective and well-tolerated surgery to address acquired NLDO.

The most common indication for DCR is acquired nasolacrimal duct obstruction (NLDO), which may be caused by infection, inflammation, neoplasia, trauma, or age-related fibrosis of the nasolacrimal duct.3

Contraindications: Contraindications for this surgery have been noted to include patients with active dacryocystitis with abscess formation and lacrimal system neoplasms.4-5 Ensuring meticulous assessment and management of hemostasis is critical to a successful external DCR.

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A thorough ocular history should be obtained. This is done to differentiate between epiphora from acquired or congenital nasolacrimal duct obstruction, as well as reflexive epiphora from other etiologies. A dilated fundus exam and slit lamp biomicroscopy are performed. Tear meniscus height is measured. Nasolacrimal outflow is evaluated with probing and irrigation.5-6

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The external approach to DCR involves the removal of bone adjacent to the nasolacrimal sac, joining the lacrimal sac with nasal mucosa, and insertion of a nasolacrimal stent to bypass the nasolacrimal duct obstruction and create a new pathway to drain tears from the canaliculi into the nasal cavity. Advantages of an external DCR include high success rates (>90%), adequate visualization of lacrimal sac (to assess for pathology such as stones or tumors), and optimized positioning of the new bypass system with direct suturing of the nasolacrimal sac to the nasal mucosal flaps.1 In comparison to endoscopic DCR which is performed with an endoscope, disadvantages of external DCR include potential for scar formation and longer operative time. More robust data is needed to compare the efficacy of endoscopic versus external DCR.2

Results: In our case, the primary objective was to reduce fluid and mucus retention in the lacrimal sac and increase tear drainage as a consequence of NLDO in a patient with a history of dacryocystitis of rare fungal etiology. In addition, the insertion of a bicanalicular Crawford stent served to enhance drainage and maintain patency of the nasolacrimal system. Post-operatively, mild epistaxis may occur and usually ceases after 24 hours. Potential complications and risks may include infection, hemorrhage, facial nerve injury, and persistent tearing.5 Patients are advised to avoid heavy lifting, straining, and blowing their nose for 2 weeks. The stent may be removed in approximately 3 months. Discussion: The purpose of external DCR is to bypass a nasolacrimal duct obstruction and create a new pathway for drainage of tears from the canaliculi into the nasal cavity. Both external and endoscopic DCR can be effective in these settings.1 Less invasive options may be considered depending on the cause of NLDO. For example, in children with suspected congenital NLDO, conservative treatment with antibiotics and Crigler massages is the first line therapy, as greater than 90% of these patients experience spontaneous resolution by 1 year of age.7 If external DCR is indicated, proper surgical technique is critical to minimize post-operative complications that may require additional medical therapy or surgical treatment. One systematic review of potential therapeutic strategies for distal acquired lacrimal obstruction indicated that endoscopic DCR could be considered the treatment of choice in revision cases.8 Some ophthalmologists favor external DCR because of a history of high primary success rates, ease of inspection for pathology of the lacrimal sac (such as dacryoliths and tumors), and the ability to more easily suture mucosal flaps.9 When selecting external DCR, review of the potential for tumor spread when breaching the bony barrier and identifying any history of prior radiotherapy in the medial canthal region can reduce post-operative complications.5

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Special thanks to Dr. Nahyoung Grace Lee who performed the surgery, as well as Dr. Joseph Arboleda and Dr. Silas Wang who oversee the Harvard Ophthalmology Research Scholars Program.

1. Sobel RK, Aakalu VK, Wladis EJ, Bilyk JR, Yen MT, Mawn LA. A Comparison of Endonasal Dacryocystorhinostomy and External Dacryocystorhinostomy: A Report by the American Academy of Ophthalmology. Ophthalmology. 2019;126(11):1580-1585. doi:10.1016/j.ophtha.2019.06.009. https://pubmed.ncbi.nlm.nih.gov/31358391/ 2. Marcet MM, Kuk AK, Phelps PO. Evidence-based review of surgical practices in endoscopic endonasal dacryocystorhinostomy for primary acquired nasolacrimal duct obstruction and other new indications. Curr Opin Ophthalmol. 2014;25(5):443-448. doi:10.1097/ICU.0000000000000084. https://pubmed.ncbi.nlm.nih.gov/24979582/ 3. Makselis A, Petroska D, Kadziauskiene A, et al. Acquired nasolacrimal duct obstruction: clinical and histological findings of 275 cases. BMC Ophthalmol. 2022;22(1):12. Published 2022 Jan 5. doi:10.1186/s12886-021-02185-x. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8734260/ 4. Lee TS, Woog JJ. Endonasal dacryocystorhinostomy in the primary treatment of acute dacryocystitis with abscess formation. Ophthalmic Plast Reconstr Surg. 2001;17(3):180-183. doi:10.1097/00002341-200105000-00006. https://pubmed.ncbi.nlm.nih.gov/11388383/ 5. Ullrich K, Malhotra R, Patel BC. Dacryocystorhinostomy. In: StatPearls. Treasure Island (FL): StatPearls Publishing; August 7, 2023. https://pubmed.ncbi.nlm.nih.gov/32496731/ 6. Burkat CN, Lucarelli MJ. Tear meniscus level as an indicator of nasolacrimal obstruction. Ophthalmology. 2005;112(2):344-348. doi:10.1016/j.ophtha.2004.07.030. https://pubmed.ncbi.nlm.nih.gov/15691573/ 7. Pinar-Sueiro S, Sota M, Lerchundi TX, et al. Dacryocystitis: Systematic Approach to Diagnosis and Therapy. Curr Infect Dis Rep. January 29, 2012. doi:10.1007/s11908-012-0238-8. https://pubmed.ncbi.nlm.nih.gov/22286338/ 8. Vinciguerra A, Resti AG, Rampi A, Bussi M, Bandello F, Trimarchi M. Endoscopic and external dacryocystorhinostomy: A therapeutic proposal for distal acquired lacrimal obstructions. Eur J Ophthalmol. 2023;33(3):1287-1293. doi:10.1177/11206721221132746. 9. Watkins LM, Janfaza P, Rubin PA. The evolution of endonasal dacryocystorhinostomy. Surv Ophthalmol. 2003;48(1):73-84. doi:10.1016/s0039-6257(02)00397-1. https://pubmed.ncbi.nlm.nih.gov/12559328/