Differential Canalograms Detect Outflow Changes from Trabecular Micro-Bypass Stents and Ab Interno Trabeculectomy.
Recently introduced microincisional glaucoma surgeries that enhance conventional outflow offer a favorable risk profile over traditional surgeries, but can be unpredictable. Two paramount challenges are the lack of an adequate training model for angle surgeries and the absence of an intraoperative quantification of surgical success. To address both, we developed an ex vivo training system and a differential, quantitative canalography method that uses slope-adjusted fluorescence intensities of two different chromophores to avoid quenching. We assessed outflow enhancement by trabecular micro-bypass (TMB) implantation or by ab interno trabeculectomy (AIT). In this porcine model, TMB resulted in an insignificant (p > 0.05) outflow increase of 13 ± 5%, 14 ± 8%, 9 ± 3%, and 24 ± 9% in the inferonasal, superonasal, superotemporal, and inferotemporal quadrant, respectively. AIT caused a 100 ± 50% (p = 0.002), 75 ± 28% (p = 0.002), 19 ± 8%, and 40 ± 21% increase in those quadrants. The direct gonioscopy and tactile feedback provided a surgical experience that was very similar to that in human patients. Despite the more narrow and discontinuous circumferential drainage elements in the pig with potential for underperformance or partial stent obstruction, unequivocal patterns of focal outflow enhancement by TMB were seen in this training model. AIT achieved extensive access to outflow pathways beyond the surgical site itself.
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.|New Jersey Medical School, Rutgers State University of New Jersey, Newark, NJ 07103, United States.
Hardik A
HA
Parikh
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.
Ralitsa T
RT
Loewen
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.
Pritha
P
Roy
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.|Department of Ophthalmology, New York University School of Medicine, NY 10016, United States.|Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15261, United States.
Joel S
JS
Schuman
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.|Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15261, United States.
Kira L
KL
Lathrop
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.
Nils A
NA
Loewen
D000818:Animals; D001082:Aqueous Humor / Q000000981:diagnostic imaging*; D019793:Fluorescein / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D005902:Glaucoma, Open-Angle / Q000601:surgery; D006068:Gonioscopy / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D023421:Models, Animal; D011231:Preceptorship / Q000379:methods; D015607:Stents / Q000662:veterinary; D013552:Swine; D059008:Time-Lapse Imaging; D014129:Trabecular Meshwork / Q000601:surgery*; D014130:Trabeculectomy / Q000193:education / Q000295:instrumentation / Q000379:methods* / Q000662:veterinary*; D014966:Xanthenes / Q000737:chemistry
D005456:Fluorescent Dyes; D014966:Xanthenes; C034657:Texas red; D019793:Fluorescein