title: Scanning Electron Microscopic Features of Nasolacrimal Silastic Stents Retained for Prolong Durations Following Dacryocystorhinostomy.
abstract: OBJECTIVE
  The aims of this study were to examine the scanning electron microscopic features of silastic nasolacrimal duct stents retained for long durations following a dacryocystorhinostomy.
  
  
  METHODS
  A prospective interventional study was performed on stents retrieved from patients who were lost to follow up after a dacryocystorhinostomy with Crawford stent insertion. Long duration was defined as stents retrieved at a minimum of 1 year following a dacryocystorhinostomy. None of the patients had any evidence of postoperative infection. After removal, the stent segments were subjected to biofilm and physical deposit analysis using standard protocols of scanning electron microscopy. These stent segments were compared against sterile stents which acted as controls.
  
  
  RESULTS
  A total of 7 stents were studied. Five were consecutive patient samples, and 2 were sterile stents. All the 5 stents were retrieved from patients who were lost to follow up for a minimum of 12 months following surgery. The mean duration of intubation at retrieval was 21 months. All the stents demonstrated evidence of biofilm formation and physical deposits. However, as the duration of retention increased, the deposits and biofilms were noted to be progressively denser, multilayered and extensive. Certain areas demonstrated thick biofilm integration with the deposits. Polymicrobial communities were noted within the exopolysaccharide matrix.
  
  
  CONCLUSIONS
  This is the first study to exclusively report on scanning electron microscopic features of lacrimal stents retained for long durations. Further studies on physical elements within the deposits and protein analysis would provide more insights into stent-tissue interactions.
authors.affiliation: *Dacryology Service, L.V. Prasad Eye Institute; †Department of Pathology, Global Hospital; and ‡Ruska Labs, College of Veterinary Sciences, Hyderabad, India.
authors.forename: Mohammad Javed
authors.initials: MJ
authors.lastname: Ali
authors.forename: Farhana
authors.initials: F
authors.lastname: Baig
authors.forename: Mekala
authors.initials: M
authors.lastname: Lakshman
authors.forename: Milind N
authors.initials: MN
authors.lastname: Naik
mesh_terms: D001419:Bacteria / Q000648:ultrastructure*; D018407:Bacterial Physiological Phenomena; D018441:Biofilms; D003608:Dacryocystorhinostomy; D020878:Device Removal; D004129:Dimethylpolysiloxanes; D006801:Humans; D007440:Intubation / Q000295:instrumentation*; D008855:Microscopy, Electron, Scanning; D009301:Nasolacrimal Duct / Q000601:surgery*; D011446:Prospective Studies; D015607:Stents / Q000382:microbiology*
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon