Insertion of a preloaded Monoka™ stent for congenital nasolacrimal obstruction: Intraoperative observations. A preliminary study

Abstract

To study the intraoperative deployment of a pre-loaded probe for a "pushed" monocanalicular nasolacrimal intubation. Non-randomized study of consecutive cases. Description: A classical Monoka™ silicone stent with the silicone tube attached at right angles to the punctal plug is contained entirely inside an introducer connected to a piston. Insertion: The procedure begins with intubation of the nasolacrimal duct with the metallic introducer. Traction on the piston retracts the metallic introducer inside the handpiece. This relative shortening progressively ejects the stent, starting with its free end at the bottom of the introducer. The operation was observed endoscopically under single-blind conditions. Twenty-eight preloaded Monoka™ stents were placed consecutively, in 28 congenital nasolacrimal duct intubations in 22 patients (28 sides). Endoscopic examination showed that the free part of the stent was progressively ejected from the introducer during retraction of the piston. Insertion of this pushed stent into the nasal cavity was effective in 23/28 cases (82.1%). A total of 28 preloaded stent insertions were attempted and 23 were correctly deployed. At the end of nasolacrimal duct intubation, contact between the punctal plug and the lacrimal punctum was problematic in four cases (4/28=14.2%). At the beginning of stent placement, premature ejection of the punctal plug within the end of the introducer occurred in five cases (5/28=17.8%). These five stents failed to insert properly into the nasal cavity. At the end of insertion, retention of the punctal plug in the introducer occurred in two cases (2/28=7.1%). No cases of intraoperative or postoperative epistaxis were observed. Intraoperative nasal endoscopy validated the concept of the preloaded Monoka stent and its deployment. Reproducibility and improved reliability may require a change in stenting technique and a design modification.