title: Canaloplasty with Stegmann Canal Expander for primary open-angle glaucoma: two-year clinical results.
abstract: OBJECTIVE
  To examine longer-term postsurgical safety and efficacy of a new expander for Schlemm's canal.
  
  
  METHODS
  In a non-comparative, prospective study, 42 White patients with medically uncontrolled primary open-angle glaucoma (POAG) underwent primary canaloplasty with >2-year follow-up. The bleb-independent procedure comprised catheter-assisted canaloplasty and implantation of two Stegmann Canal Expanders to maintain trabecular distension and canal patency over 180°. Intraocular pressure (IOP), glaucoma medication use and complications were assessed.
  
  
  RESULTS
  Mean IOP was 26.8 ± 5.6 mmHg presurgery, 12.8 ± 1.5 mmHg at 6 months, 13.2 ± 1.2 mmHg at 12 months and 13.3 ± 2.5 mmHg at 24 months (p < 0.001). Rate of complete success, defined as IOP ≤21, ≤18 and ≤16 mmHg and a ≥ 30% IOP reduction, was 85% (95% CI: 0.76-0.95), 85% (0.76-0.95) and 82% (0.70-0.96) at 12 months and 83% (0.73-0.94), 80% (0.70-0.92) and 80% (0.70-0.92) at 24 months. Preoperative factors were not significant predictors of ≤16 mmHg IOP reduction: IOP (hazard ratio [HR]: 0.68; 95% CI: 0.44-1.04; p = 0.08), mean visual defect (1.06; 0.90-1.20; p = 0.47), number of medications (0.59; 0.17-2.14; p = 0.42) and age (0.96; 0.87-1.13; p = 0.41). Number of medications dropped from 2.8 ± 0.4 presurgery to 0.2 ± 0.5 postsurgery (p < 0.001). Mean preoperative best-corrected visual acuity was 0.19 ± SD 0.21 (range: 0-1.6), and logMAR was similar to 0.23 ± 0.16 (range: 0-1.6; p = 0.42) after a mean follow-up of 27.4 months. Complications included peripheral Descemet's membrane detachment (7.2%) and trimming of the expander (4.7%) during surgery, and transient microhyphaema (23.8%) and IOP elevation (7.2%) postsurgery.
  
  
  CONCLUSIONS
  Canaloplasty with the Stegmann Canal Expander was a safe and effective procedure to reduce IOP in White patients with moderate to advanced POAG.
authors.affiliation: Department of Ophthalmology, Sefako Makgatho Health Sciences University (former Medical University of Southern Africa); Medunsa, Pretoria, South Africa.|Department of Ophthalmology, University of Basel, Basel, Switzerland.
authors.forename: Matthias C
authors.initials: MC
authors.lastname: Grieshaber
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland.|Center for Biomedical Statistics, University of Basel, Basel, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schoetzau
authors.affiliation: Grieshaber Ophthalmic Research Foundation, Schaffhausen, Switzerland.
authors.forename: Hans R
authors.initials: HR
authors.lastname: Grieshaber
authors.affiliation: Department of Ophthalmology, Sefako Makgatho Health Sciences University (former Medical University of Southern Africa); Medunsa, Pretoria, South Africa.
authors.forename: Robert
authors.initials: R
authors.lastname: Stegmann
mesh_terms: D000368:Aged; D002404:Catheterization / Q000379:methods*; D005260:Female; D018463:Filtering Surgery / Q000379:methods*; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D011446:Prospective Studies; D019736:Prostheses and Implants; D019651:Plastic Surgery Procedures / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome; D014792:Visual Acuity
keywords: Schlemm's canal; canaloplasty; collector channel; expander; non-penetrating glaucoma surgery; viscocanalostomy