Scanning electron microscopic features of lacrimal drainage silastic stents: Comparison of various Crawford and large-diameter stents.

PURPOSE: This study aimed to examine the differences in the biofilms and physical deposits on Crawford stents compared to large-diameter stents. METHODS: A prospective interventional study was performed on a series of patients undergoing external or endoscopic dacryocystorhinostomy (DCR) and endoluminal lacrimal duct recanalization (ELDR) with either Crawford or large-diameter stents. All the Crawford stents were retrieved at six weeks and the large-diameter ones at eight weeks following the surgical intervention. There was no evidence of post-operative infection in any of the patients. Following extubation, standard protocols of scanning electron microscopy were used to assess the biofilms and physical deposits on the stents. RESULTS: A total of 15 stents were studied. Of these, twelve were Crawford, and three were large-diameter stents. The Crawford stents were from two different manufacturers. All the stents demonstrated evidence of biofilm formation and physical deposits. The Crawford stents showed thin biofilms and sparse physical deposits, but there were no demonstrable differences amongst stents from different manufacturers. However, the deposits and biofilms were thicker and more extensive in the large-diameter stents than the Crawford ones. The biofilms from all stents showed the presence of polymicrobial communities within the exopolysaccharide matrix. CONCLUSIONS: The present study found differences in biofilms and physical deposits between Crawford and large-diameter stents. These differences can be partly explained by stent duration, size, and their tissue interactions.

Cadaveric Evaluation of the Canalicular-Lacrimal Sac-Mucosal Folds and Clinical Implications.

PURPOSE: The purpose is to study the anatomical variations of the characteristic mucosal folds at the canalicular-lacrimal sac junction and their potential clinical implications. METHODS: Twelve lacrimal drainage systems of six fresh frozen Caucasian cadavers were studied to assess the openings of the common canaliculus into the lacrimal sac. A standard endoscopic dacryocystorhinostomy was performed until complete lacrimal sac marsupialization and reflection of the flaps. All specimens were subjected to clinical assessment of lacrimal patency via irrigation. A high-definition nasal endoscopy assessed the internal common opening and the mucosal folds in its close vicinity. Probing at the internal common opening was performed to aid in the assessment of the folds. Videography and photo documentation was performed. RESULTS: All 12 specimens had a single common canalicular opening. Ten of the 12 specimens (83.3%) were noted to have canalicular/lacrimal sac-mucosal folds (CLS-MF). Anatomical variations were noted across these 10 specimens and included inferior 180° (n = 6), anterior 270° (n = 2), posterior 180° (n = 1), and 360° CLS-MF (n = 1). Cases were randomly chosen to demonstrate the clinical implications of misinterpreting them as canalicular obstructions or the potential to cause an inadvertent false passage. CONCLUSION: The inferior 180° was the most common CLS-MF noted in the cadaveric study. It is helpful for clinicians to recognize the prominent CLS-MF and their clinical implications intraoperatively. Further fundamental work is needed to characterize the anatomy and the possible physiological role of CLS-MFs.