title: Exit strategies in canaloplasty: intraoperative conversion into 180-degree trabeculotomy or 360-degree trabeculotomy in cases of unsuccessful catheterisation of Schlemm's canal: influence of degree of canal cleavage.
abstract: OBJECTIVE
  To investigate the safety and efficacy of intraoperative conversion of unsuccessful canaloplasty technique into 180-degree metal or 360-degree suture trabeculotomy.
  
  
  METHODS
  In this retrospective observational case series, 35 eyes of 35 patients with open-angle glaucoma (OAG) who had undergone unsuccessful canaloplasty technique and underwent intraoperative conversion were studied. In 17 eyes (group A), the procedure was converted into 180-degree metal trabeculotomy because of unsuccessful circumferential Schlemm's canal (SC) catheterisation. Group B included 18 eyes that were converted into 360-degree trabeculotomy because of cheese wiring of tension suture through the trabecular meshwork (TM) after successful complete catheterisation of SC.
  
  
  RESULTS
  Median preoperative IOP was 22.0 mmHg (range 16-34) in group A, and 22.0 mmHg (range 15-48) in group B. Median IOP was significantly reduced in both groups postoperatively, at the 12-month examination to 15.0 mmHg (range 9-21) representing a reduction of 36 % in group A, and to 14.5 mmHg (range 8-21) representing a reduction of 34 % in group B. Median glaucoma medication number decreased significantly from 4 (range 2-4) and 3 (range 1-4) preoperatively to 2 (range 0-4) and 1 (range 0-3) at 12 months in groups A and B respectively. Hyphema was the commonest complication, with an incidence of 76 % in group A and 78 % in group B.
  
  
  CONCLUSIONS
  180-degree metal or 360-degree suture/catheter trabeculotomy are safe and effective surgical backup methods to control IOP in cases of unsuccessful intracanalicular placement of tension suture during canaloplasty surgery.
authors.affiliation: Centre for Ophthalmology, University Hospital Tübingen, Schleichstr. 12-16, 72076, Tübingen, Germany, onahrawy@hotmail.com.
authors.forename: Omar
authors.initials: O
authors.lastname: Alnahrawy
authors.forename: Gunnar
authors.initials: G
authors.lastname: Blumenstock
authors.forename: Focke
authors.initials: F
authors.lastname: Ziemssen
authors.forename: Peter
authors.initials: P
authors.lastname: Szurman
authors.forename: Martin Alexander
authors.initials: MA
authors.lastname: Leitritz
authors.forename: Spyridon
authors.initials: S
authors.lastname: Dimopoulos
authors.forename: Bogomil
authors.initials: B
authors.lastname: Voykov
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001082:Aqueous Humor / Q000378:metabolism; D002404:Catheterization; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D007432:Intraoperative Period; D016850:Limbus Corneae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013536:Suture Techniques; D014129:Trabecular Meshwork / Q000601:surgery*; D014130:Trabeculectomy / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult