June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017

Rapid learning curve assessment in an ex vivo training system for microincisional glaucoma surgery
Author Affiliations & Notes
  • CHAO WANG
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
    Xiangya School of Medicine, Central South University, Changsha, Hunan, China
  • Yalong Dang
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Susannah Waxman
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Hardik Parikh
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Igor I Bussel
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Ralitsa Loewen
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Xiaobo Xia
    Department of Ophthalmology, Xiangya Hospital of Central South University, Changsha, Hunan, China
  • Kira L Lathrop
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Richard Anthony Bilonick
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
    Biostatistics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, United States
  • Nils Loewen
    Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Footnotes
    Commercial Relationships   CHAO WANG, None; Yalong Dang, None; Susannah Waxman, None; Hardik Parikh, None; Igor Bussel, None; Ralitsa Loewen, None; Xiaobo Xia, None; Kira Lathrop, None; Richard Bilonick, None; Nils Loewen, None
  • Footnotes
    Support  National Institutes of Health Grant K08EY022737-01 (NAL). Core Grant EY-08098.
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 4929. doi:
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    • Get Citation

      CHAO WANG, Yalong Dang, Susannah Waxman, Hardik Parikh, Igor I Bussel, Ralitsa Loewen, Xiaobo Xia, Kira L Lathrop, Richard Anthony Bilonick, Nils Loewen;
      Rapid learning curve assessment in an ex vivo training system for microincisional glaucoma surgery. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4929.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Microincisional glaucoma surgeons operate in a highly confined space, making it difficult to learn by observation or assistance alone. An ex vivo model would allow for better refinement of technique, quantification of progress and computation of a learning curve.

Methods :
Seven resident trainees without angle surgery experience performed nine ab interno trabeculectomies in pig eyes after preparing with training slides and videos. They placed the eyes on a tiltable mannequin head, visualized the trabecular meshwork gonioscopically through an ophthalmic microscope and removed it by trabectome-mediated plasma ablation(Figure 1). An expert surgeon observed, guided, and rated the procedure using an Operating Room Score (ORS). The extent of accessed outflow beds was estimated with canalograms using 0.5-micron fluorescent microspheres. Data was fit using mixed effect models.

Results :
ORS was fit by an asymptotic nonlinear mixed effects model with a fixed upper asymptote, an estimated lower asymptote, and an estimated logarithmic rate constant, and including random effects for the lower asymptote and for the rate constant. A half-maximum was achieved after 2.5 eyes. Surgical time decreased by 1.4 minutes per eye in a linear fashion. The ablation arc followed a sigmoidal function with a half-maximum inflection point after 5.3 eyes and the mean arc improved from 73 to 135°. Despite these changes, canalograms revealed that the improvement in arc angle did not correlate well with improvement in outflow(Figure 2).

Conclusions :
This inexpensive pig eye model provides a safe and effective training model for ab interno trabeculectomy and allows for quantification of outcomes. Trainees without prior angle surgery experience proceeded quickly on the learning curve. Actual outflow improvements progressed at a slower rate, a reminder to remain humbly committed to training.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 


Figure 1. Setup for microinvasive glaucoma surgery.


Figure 1. Setup for microinvasive glaucoma surgery.

 

Figure 2. A)The Operating Room Score (ORS). B) Surgical time and eye number. C)The improvement of ablation arc length . D)Fluorescent canalograms along the individual learning curve of trainees #1 through #7

Figure 2. A)The Operating Room Score (ORS). B) Surgical time and eye number. C)The improvement of ablation arc length . D)Fluorescent canalograms along the individual learning curve of trainees #1 through #7

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