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. 2022 Nov 25:16:3919-3926.
doi: 10.2147/OPTH.S392021. eCollection 2022.

Development and Application of a New T-shaped Internal Trabeculotomy Hook (T-hook)

Etsuo Chihara  1 , Tomoyuki Chihara  1
Affiliations

Development and Application of a New T-shaped Internal Trabeculotomy Hook (T-hook)

Etsuo Chihara et al. Clin Ophthalmol. .

Abstract

Purpose: We introduce a newly designed T-shaped internal trabeculotomy hook and compare its surgical outcomes with those of Kahook dual blade (KDB) surgery.

Patients and methods: One eye each of seventeen and sixty-one patients underwent T-hook and KDB surgeries, respectively. Post-surgical intraocular pressure (IOP), medications, visual acuity, and prevalence of IOP spikes and hyphema were compared between the two cohorts.

Results: The utility of the T-hook was excellent and enabled the easy opening of the Schlemm's canal. The pre-surgical IOP of 25.6 ±7.5 mmHg in the T-hook cohort decreased to 14.1 ± 4.3 (-41.2% reduction) and 15.0 ± 3.1mmHg (-39.3% reduction) at 3 (P<0.001) and 6 months (P=0.003), respectively. Pre-surgical medications of 2.8 decreased to 2.3 and 2.0 medications, respectively, at 3 and 6 months. The best-corrected visual acuity (BCVA) improved from the pre-surgical logarithm of the minimum angle resolution (logMAR) of 0.148 to -0.012 at three months (P=0.036,). While the pre-surgical IOP of 24.9±4.3 mmHg in the KDB cohort decreased to 16.5±5.7 mmHg (-35.5%, P<0.001) and 16.1±3.4 mmHg (-33.5%, P<0.001) at 3 and 6 months, respectively. Reduction in medications at 3- and 12-month timepoints (from 2.8 to 1.7 and 1.7, respectively; P<0.001) and improvement in BCVA at three months (from 0.106 to -0.025 logMAR, P<0.001) were also significant. There was no difference between the T-hook and KDB cohorts in terms of the pre-surgical IOP (P=0.15) and post-surgical IOP at 1 (P=0.27), 3 (P=0.17), 6 (P=0.47), and 12 months (P=0.11, Mann-Whitney U-test). The prevalence of a post-surgical IOP spike in the T-hook and KDB cohorts was 41.2% and 47.5%, and that of post-surgical hyphema was 17.6% and 26.2%, respectively.

Conclusion: The novel T-hook was easy to use and was as useful as the KDB device in performing internal trabeculotomy.

Keywords: MIGS; Schlemm’s canal; T-hook; double mirror gonio lens; minimally invasive glaucoma surgery; nonpenetrating glaucoma surgery; trabecular meshwork.

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Conflict of interest statement

The authors are currently applying for a patent for the design of the T-hook. The authors report no other conflicts of interest in this work.

Figures

Figure 1
Figure 1
(A) Overview of the T-hook. The tip of the T-hook is curved to avoid damaging the outer wall of the Schlemm’s canal, and the blades on both sides can easily open the trabecular meshwork. The T-hook can cut both the left and right trabecular meshwork using a single insertion procedure. If surgeons create three different corneal incisions with a 120-degree distance using a double mirror gonio lens (ex. Ahmed Gonio lens), a 360-degree internal trabeculotomy can be performed. (B) Photographs of the prototypes of the T-hook. The angle, thickness, and configuration of the tip were changed 5 times.
Figure 2
Figure 2
Images of the surgical procedures for dissection of the right trabecular meshwork. The asterisk indicates the first insertion site. Note the scarcity of bleeding events.
Figure 3
Figure 3
Images of surgical procedures for dissection of the contralateral trabecular meshwork.
Figure 4
Figure 4
Probability to achieve an IOP of 17 mmHg assessed by Kaplan–Meier life table analysis. Log rank test revealed no difference between the T-hook and KDB cohorts (P=0.957).
Figure 5
Figure 5
Probability to achieve an IOP of 21 mmHg assessed by Kaplan–Meier life table analysis. Log rank test revealed no difference between the T-hook and KDB cohorts (P=0.351).
See this image and copyright information in PMC

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References

    1. Seibold LK, Soohoo JR, Ammer DA, Kahook MY. Preclinical investigation of ab interno trabeculectomy using a novel dual-blade device. Am J Ophthalmol. 2013;155(3):524–529. doi:10.1016/j.ajo.2012.09.023 - DOI - PubMed
    1. Grover DS, Godfrey DG, Smith O, et al. Gonioscopy-assisted transluminal trabeculotomy, ab interno trabeculotomy: technique report and preliminary results. Ophthalmology. 2014;121(4):855–861. doi:10.1016/j.ophtha.2013.11.001 - DOI - PubMed
    1. Chin S, Nitta T, Shinmei Y, et al. Reduction of intraocular pressure using a modified 360-degree suture trabeculotomy technique in primary and secondary open-angle glaucoma: a pilot study. J Glaucoma. 2012;21:401–407. doi:10.1097/IJG.0b013e318218240c - DOI - PubMed
    1. Tanito M, Sano I, Ikeda Y, Fujihara E. Short-term results of microhook ab interno trabeculotomy, a novel minimally invasive glaucoma surgery in Japanese eyes: initial case series. Acta Ophthalmol. 2017;95(5):e354–360. doi:10.1111/aos.13288 - DOI - PubMed
    1. Tanito M, Sano I, Ikeda Y, Fujihara E. Microhook ab interno trabeculotomy, a novel minimally invasive glaucoma surgery in eyes with open-angle glaucoma with scleral thinning. Acta Ophthalmol. 2016;94(5):e371–e372. doi:10.1111/aos.12888 - DOI - PubMed

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