Endonasal Dacryocystorhinostomy With Mucosal Flaps

Diseases within the tear duct system can interfere with tear drainage and result in epiphora. Poor drainage with secretion retention may result in inflammation and infection. In the majority of cases, epiphora is attributed to an outflow obstruction of the nasolacrimal duct. To date, the exact etiology is not completely understood, but inflammatory alterations with stenosis at the junction between the lacrimal sac and nasolacrimal duct represent the predominant cause of acquired nasolacrimal duct obstruction. Iatrogenic damage may also result in postoperative epiphora.

As conservative care is usually ineffective, surgical procedures are the treatment of choice for distal lacrimal system pathology. Topographically there is a close proximity of the lacrimal sac and nasolacrimal duct to the nasal cavity and the paranasal sinuses, so that localized pathologic changes can also influence the tear drainage ( Box 14.1 ).

The history of surgical interventions of the lacrimal system dates back to antiquity. Modern surgical techniques were developed more than 100 years ago with the description of external dacryocystorhinostomy (DCR) by the Italian rhinologist A. Toti in 1904 and Caldwell’s proposal of endonasal DCR. Since then both methods have been competitively applied and further modified. Which method results in better outcomes is controversially discussed in the current literature. External DCR is a well-established procedure performed since the early 20th century with stable outcomes between 90% and 95% in the best hands. After Caldwell’s first description of endoscopic DCR, surgeons discovered this technique again about three decades ago. Despite significant technical progress, these early attempts to perform endoscopic DCR were not as successful as the external approach, with success ranging from 55% to 90%.

Various studies showed that the main reason for unsuccessful surgery is creating an opening in the lacrimal duct that is too small. Recent publications have shown that only a significant endoscopic resection of the lacrimal bone and the frontal process of maxilla with exposure of the entire lacrimal sac guarantees success rates equivalent to external approaches. In contrast, laser DCR allows creation of only a small ostia and has significantly lower success rates. A crucial factor contributing to success has been the understanding of the endoscopic anatomy of the lacrimal sac. Initially it was assumed that the sac extends only slightly beyond the level of the axilla of the middle turbinate ( Fig. 14.1 ). However, imaging procedures revealed that it extends significantly above the insertion of the middle turbinate (about 8 mm above the axilla). Various clinical and cadaveric studies further elucidated intranasal anatomy of the lacrimal sac in relation to other structures on the lateral nasal wall, which led to safer and more effective surgical techniques. The accurate definition of the exact intranasal position of the lacrimal sac was an essential step toward successful endoscopic DCR. The second important factor was wide marsupialization of the completely exposed sac with approximation of the lacrimal and nasal mucosa that allowed the sac to heal without granulation tissue and subsequent scarring. As a result, a novel powered endoscopic DCR approach was developed.

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The sac extends significantly above the axilla (8 to 10 mm) and lies anterior to the middle turbinate ( MT ). IT, inferior turbinate.