Surgical timing and presence of a vitreoretinal fellow on postoperative adverse events following pars plana vitrectomy

Introduction: To evaluate the adverse event rate following pars plana vitrectomy as a function of surgical start time and the presence of a vitreoretinal fellow. Methods: Single-institution retrospective cohort study of patients undergoing pars plana vitrectomy from 1 January 2016 to 31 December 2016 at Stanford University School of Medicine (Palo Alto, CA, USA). Records were reviewed for surgical start time, the presence of vitreoretinal fellow, and postoperative adverse events defined as any finding deviating from the expected postoperative course requiring observation or intervention. Results: A total of 310 pars plana vitrectomies were performed. There was no statistical difference in the rate of any adverse event when comparing cases starting after 16:01 (9/13, 69.2%) and after 12:01 (42/99, 42.4%) to a morning start time (69/198, 34.9%, adjusted p = 0.083). There was a statistically significant increase in the risk of postoperative vitreous hemorrhage with afternoon and evening cases as compared to morning cases (adjusted p = 0.021). In addition, there was no difference in any adverse event with a fellow present (93/244, 38.1%) compared to without (27/66, 40.9%, adjusted p = 0.163). There was a higher risk of postoperative hypotony when a fellow was involved (6.6% vs 0%, p = 0.028), though this difference disappeared after adjusting for confounders (adjusted p = 0.252). There was no difference in the length of surgery with and without a fellow (49 vs 54 min, respectively; p = 0.990). Discussion: Afternoon start time and the presence of a fellow were not independent risk factors for postoperative adverse events.