title: Retinal vascular occlusion after vitrectomy with retrobulbar anesthesia-observational case series and survey of literature.
abstract: BACKGROUND
  Severe postoperative loss of vision has been occasionally reported as a rare complication of retrobulbar anesthesia, and several possible causes have been proposed in the literature. In this work, our own and other investigators' experiences with these complications are surveyed with a view to identifying its pathophysiology.
  
  
  METHODS
  This observational case series refers to six patients who presented during a 3-month period with occlusion of either the central artery itself (n = 3) or a branch thereof (n = 3) 2-14 days after uneventful vitreoretinal surgery following retrobulbar anesthesia with a commercial preparation of mepivacaine (1% Scandicain®, Astra Chemicals, Sweden) containing methyl- and propyl parahydroxybenzoate as preservatives.
  
  
  RESULTS
  Three of the patients carried risk factors, which were medically controlled. In three individuals, vasoocclusion was observed after a second vitreoretinal intervention, which was performed 3-12 months after uneventful primary surgery. Good visual recovery was observed in only one instance.
  
  
  CONCLUSIONS
  In patients who were anesthetized with preservative-free mepivacaine, no vasoocclusion occurred. In individuals who were anesthetized with mepivacaine containing the preservatives methyl- and propyl parahydroxybenzoate, a tenfold increase in the incidence of eyes requiring re-operation was documented, with a 2- to 14-day lapse in the onset of vasoocclusion. These findings reveal a possible implication of preservatives contained in the local anesthetic solution for the vasoocclusive events. Due to this potential hazard, the use of preservative-free preparations of local anesthesia in ocular surgery is emphasized in order to prevent this sight-threatening complication.
authors.affiliation: Department of Ophthalmology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Tappeiner
authors.forename: Justus G
authors.initials: JG
authors.lastname: Garweg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects*; D019773:Epiretinal Membrane / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008619:Mepivacaine / Q000008:administration & dosage / Q000009:adverse effects; D008875:Middle Aged; D009915:Orbit; D010226:Parabens / Q000008:administration & dosage / Q000009:adverse effects*; D011310:Preservatives, Pharmaceutical / Q000008:administration & dosage / Q000009:adverse effects*; D015356:Retinal Artery Occlusion / Q000139:chemically induced* / Q000175:diagnosis; D012307:Risk Factors; D014792:Visual Acuity / Q000502:physiology; D014821:Vitrectomy; D014823:Vitreous Hemorrhage / Q000601:surgery
chemical_list: D000779:Anesthetics, Local; D010226:Parabens; D011310:Preservatives, Pharmaceutical; C015358:methylparaben; D008619:Mepivacaine; C006068:propylparaben