title: Twisting maneuver for sutureless vitrectomy trocar insertion to reduce intraoperative intraocular pressure rise.
abstract: OBJECTIVE
  To investigate real-time intraocular pressure (IOP) during a new surgical technique-the "twisting maneuver"-when inserting a sutureless vitrectomy system trocar in porcine eyes.
  
  
  METHODS
  An interventional prospective study of 2 trocar insertion methods-direct insertion and gently twisting insertion-in a 25-gauge vitrectomy system (Alcon, Fort Worth, TX). These methods were used to create a scleral wound using a trocar blade and trocar cannula in freshly enucleated porcine eyes. The IOP changes induced by the procedures were recorded with a pressure transducer connected to the posterior chamber by direct cannulation.
  
  
  RESULTS
  Fourteen porcine eyes were studied in each group. During insertion, the mean of highest IOP rise (peak IOP rise) was 63.9 ± 25.5 mmHg in the direct insertion group compared with 30.3 ± 16.9 mmHg in the twisting insertion group (P = 0.001). During insertion, the mean of average IOP rise in the direct insertion group was 39.9 ± 16.5 mmHg compared with 21.5 ± 8.9 mmHg in the twisting insertion group (P = 0.002). The total time needed to complete the procedure in the twisting insertion group was significantly longer than that in the direct insertion group (43.3 ± 21.8 vs. 14.9 ± 8.1 seconds, P = 0.0003).
  
  
  CONCLUSIONS
  A simple modification of surgical technique, namely, using a gently twisting insertion maneuver during trocar insertion, could significantly reduce the IOP elevation to allow a safer sutureless vitrectomy.
authors.affiliation: Department of Ophthalmology, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Pei-Chang
authors.initials: PC
authors.lastname: Wu
authors.forename: Ing Soo
authors.initials: IS
authors.lastname: Tiong
authors.forename: Yao-Chi
authors.initials: YC
authors.lastname: Chuang
authors.forename: Hsi-Kung
authors.initials: HK
authors.lastname: Kuo
mesh_terms: D000818:Animals; D007429:Intraocular Pressure; D007431:Intraoperative Complications / Q000517:prevention & control*; D008866:Microsurgery / Q000295:instrumentation / Q000379:methods; D023421:Models, Animal; D009798:Ocular Hypertension / Q000517:prevention & control*; D011446:Prospective Studies; D013536:Suture Techniques; D013552:Swine; D014821:Vitrectomy / Q000295:instrumentation / Q000379:methods*