Comparison of Efficacy between 120° and 180° Schlemm’s Canal Incision Microhook Ab Interno Trabeculotomy

Round 1

Reviewer 1 Report

No further comments

Author Response

We are grateful for the time and effort expended by you in assessing this work.

Reviewer 2 Report

The issue of trabeculotomy is of great importance in for the glaucoma surgeon and data on this is direly needed. This said, I do have some significant concerns with the way this data is presented.

1. The number of patients in both groups is definitely too small to draw conclusions on the difference between 120 and 180 degrees. This should be stated more clearly (and not merely as a limitation)
2. The effect of cataract removal on IOP lowering is well described, and is not addressed at all in this manuscript. It is difficult to separate cataract effect from trabeculotomy effect, and this muddies the water even further when trying to differentiate 120 from 180. This needs to be addressed and discussed.
3. Patients in the study had an average IOP of around 17 on a little less than 3 meds. This represents a specific group of relatively controlled glaucoma patients, where presumably the reason for the operation was cataract surgery and not IOP lowering for most patients. The procedure was not tested on patients who required significant IOP lowering in this study (presumably..). This is a significant issues as it limits the generalizability of the data greatly.
4. Glaucoma severity is not described - this is a very important metric.
5. Failures - KM curves show around 50% and 30% complete and qualified success in both groups at 2 years, but no re-operations where done. Also, mean IOP was 11-13 in both groups - how does this sit with the low success rates? The data needs to be presented in full - ie a scatter plot for all patients in the study that show pre and post op IOP - would also suggest presenting medication usage differently (see WGA guidlines for recommendations).  Also a better description of the defentions of failures is necessary - where you allowed to fail before POM3? if you had an IOP above target was time allowed for addition of medications? how long? etc..
6. Importantly - as evident from the KM curves there were a lot of failures, although there is absolultely no discussion of who failed, how and why? This is critical to understanding the data.
7. Hyphema needs to be better defined - what level of AC heme was defined as hyphema? was it graded?
8. Authors postulate that 180 is no better than 120, but also mention that larger trabeculotomies cause more heme reflux from collector channels. This demonstrates an important discrepancy (and perhaps points to the underpower of this data set). This merits discussion.

I would consider not presenting 180 Vs 120 (at least not as the lead/title), but presenting all the data (with all above taken into consideration). The 120 Vs 180 can be shown as one of the analysis, of course stating that small numbers preclude a firm conclusion. 

Author Response

Point 1: The number of patients in both groups is definitely too small to draw conclusions on the difference between 120 and 180 degrees. This should be stated more clearly (and not merely as a limitation)

Response 1: Page 9 Lines 1-2 We have added “A small sample size might have led to the non-significant difference between the 120° and 180° incisions in Schlemm’s canal”.

 

Point 2: The effect of cataract removal on IOP lowering is well described, and is not addressed at all in this manuscript. It is difficult to separate cataract effect from trabeculotomy effect, and this muddies the water even further when trying to differentiate 120 from 180. This needs to be addressed and discussed.

Response 2: Page 8 Lines 20-23 We agree that it is difficult to separate cataract effect from trabeculotomy effect. We have discussed.

 

Point 3: Patients in the study had an average IOP of around 17 on a little less than 3 meds. This represents a specific group of relatively controlled glaucoma patients, where presumably the reason for the operation was cataract surgery and not IOP lowering for most patients. The procedure was not tested on patients who required significant IOP lowering in this study (presumably..). This is a significant issues as it limits the generalizability of the data greatly.

Response 3: Page 9 Lines 4-13 We have discussed.

 

Point 4: Glaucoma severity is not described - this is a very important metric.

Response 4: We have added glaucoma severity in Table 1.

 

Point 5: Failures - KM curves show around 50% and 30% complete and qualified success in both groups at 2 years, but no re-operations where done. Also, mean IOP was 11-13 in both groups - how does this sit with the low success rates? The data needs to be presented in full - ie a scatter plot for all patients in the study that show pre and post op IOP - would also suggest presenting medication usage differently (see WGA guidlines for recommendations).  Also a better description of the defentions of failures is necessary - where you allowed to fail before POM3? if you had an IOP above target was time allowed for addition of medications? how long? etc..

Response 5: Page 9 Lines 4-7 Baseline IOP was low in the current study. Therefore, IOP reduction after surgery was also low.

Figure 1 shows the scatter plot for all patients in the study that show pre and post-op IOP.

Figure 2 shows the number of preoperative and postoperative medications.

Page 5 Lines 14-16 Surgical success was achieved if, after ≥ 3 months of follow-up because of the occurrence of postoperative IOP fluctuations after trabeculotomy.

Page 5 Lines 2-3 The restarting of the IOP-lowering medications was performed in accordance with the judgement of the surgeon. Restarting IOP-lowering medications was continued.

 

Point 6: Importantly - as evident from the KM curves there were a lot of failures, although there is absolultely no discussion of who failed, how and why? This is critical to understanding the data.

Response 6: Page 9 Lines 6-8 We have shown.

 

Point 7: Hyphema needs to be better defined - what level of AC heme was defined as hyphema? was it graded?

Response 7: Page 6 Line 24 We have defined hyphema.

 

Point 8: Authors postulate that 180 is no better than 120, but also mention that larger trabeculotomies cause more heme reflux from collector channels. This demonstrates an important discrepancy (and perhaps points to the underpower of this data set). This merits discussion.

Response 8: Corneal HOAs, coma-like, and spherical-like aberrations were associated with a more extensive incision in Schlemm’s canal, thereby suggesting that extensive incisions are a risk factor in these procedures. Therefore, we strongly recommend the use of a 120° incision during Schlemm’s canal μLOT-Phaco. We also discussed that incisions more than 180° in Schlemm’s canal were likely to cause greater blood reflux from the collector channels, thereby leading to a higher frequency of postoperative hyphema. We do not understand what is discrepancy. If we have a misunderstanding about reviewer’s comments, please let us know. We have discussed that 120° incision of Schlemm’s canal had more merits than 180° incision.

 

The purpose of our current study was to examine the efficacy and safety of both the 120° and the 180° incisions in μLOT-Phaco. The most important analysis of the current study was 120° vs 180°. Therefore, we think it is necessary to present 120° vs 180° in the title.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Thank you for allowing me to review your study. I think it is an important addition to the literature. Here are my comments to improve the manuscript

      Abstract:

• Please clarify in the definition of surgical failure >20 mmhg if it is with or without glaucoma medications
• In the mean IOP (180ngroup), clarify that the mentioned results are at 12 and 24 months postoperative follow-up
• Introduction :
• When you have mentioned that first line therapy is medical please specify that to adult glaucoma because in childhood glaucoma first line therapy is surgical
• I prefer to refer to Kahook dual blade as ab-interno trabeculectomy rather than goniotomy
• Methods section:
• Please clarify what kind of "significant ocular disease" patients that were excluded from the study
• I believe the paper will benefit from a short surgical video showing the technique of ab-interno trabeculotomy by microhook for readers who are not familiar with this procedure especially that it is popular in Japan but not in other part of the world especially developing countries
• Results section:
• Add number of patients evaluated at every time point in the follow-up in Table 2 and 3
• For IOP spikes, please clarify when did the spikes happen? what was the management?
• For hyphema, please clarify extent and time of resolution of hyphema in each group
• Have any of the 2 groups required additional glaucoma surgery?
• Discussion:
• change "archived" to "achieved" in the following sentence: "On the other hand, the 360° suture trabeculotomy archived lower..."
• References:
• Reference 7 is incomplete, please edit it

 

Reviewer 2 Report

The authors investigate the surgical outcomes of patients with a minimum of 3 months follow-up after undergoing combined phacoemulsification with either a 120° or 180° incision during Schlemm’s canal microhook ab interno trabeculotomy (μLOT-Phaco) and they found that surgical outcomes were not significantly different between the 120° and 180° incisions in Schlemm’s canal.

Major concerns

The article is literally plagiarized from another article. Up to 40% plagiarism has been detected. The scientific journal JCM, given its scientific excellence, I do not consider it appropriate to continue with the publication process.

Below is the article from which all the information has been copied mainly.

Original Research

Published: 28 October 2020

Comparison of Surgical Outcomes Between Microhook Ab Interno Trabeculotomy and Goniotomy with the Kahook Dual Blade in Combination with Phacoemulsification: A Retrospective, Comparative Case Series

Ryota Aoki, Kazuyuki Hirooka, Erina Goda, Yuki Yuasa, Hideaki Okumichi, Hiromitsu Onoe & Yoshiaki Kiuchi

Advances in Therapy volume 38, pages329–336(2021)