Ab interno trabeculectomy: Outcomes in exfoliation versus primary open-angle glaucoma

Influence of Selective Laser Trabeculoplasty (SLT) on combined clear cornea phacoemulsification and Trabectome outcomes

BACKGROUND

In this retrospective comparative cohort outcome study, the influence of Selective Laser Trabeculoplasty (SLT) on combined clear cornea phacoemulsification and ab interno trabeculectomy (Trabectome) outcomes in Primary Open Angle Glaucoma (POAG), Pseudoexfoliation Glaucoma (PEX), and Pigmentary Glaucoma (PG) was examined.

METHODS

Combined clear cornea phacoemulsification and Trabectome were performed in 27 consecutive patients with POAG, in 27 patients with PEX, and in 20 patients with PG. Each group was divided into two subgroups including patients without SLT treatment prior to surgery and patients who had insufficient response to 360° SLT treatment three months prior to surgery.

RESULTS

In the SLT group, mean IOP at six months measured 13.33 ± 2.08 mmHg with an average decrease of 30 % from preoperative IOP in the POAG group, 12.10 ± 1.40 mmHg with an average decrease of 46 % in the PEX group, and 11.83 ± 2.21 mmHg with an average decrease of 38 % in the PG group. In eyes without previous SLT, mean IOP sixt 6 months measured 11.00 ± 1.73 mmHg with an average decrease of 38 % from preoperative IOP in the POAG group, 15.50 ± 1.41 mmHg with an average decrease of 35 % in the PEX group, and 15.67 ± 2.91 mmHg with an average decrease of 36 % in the PG group, respectively.

CONCLUSIONS

Prior SLT treatment seems not to negatively influence combined clear cornea phacoemulsification and Trabectome outcomes in glaucoma patients. However, SLT treatment may even have an additive effect on following combined Trabectome outcomes in patients with PEX and PG.

Techniques and outcomes of minimally invasive trabecular ablation and bypass surgery

Minimally invasive glaucoma surgeries (MIGS) can improve the conventional, pressure-dependent outflow by bypassing or ablating the trabecular meshwork (TM), or creating alternative drainage routes into the suprachoroidal or subconjunctival space. They have a highly favourable risk profile compared to penetrating surgeries, and lower intraocular pressure with variable efficacy that may depend on the extent of outflow segments accessed. Since they are highly standardised procedures that use clear corneal incisions, they can elegantly be combined with cataract and refractive procedures to improve vision in the same session. There is a growing need for surgeons to become proficient in MIGS to address the increasing prevalence of glaucoma and cataracts in a well-informed, aging population. Techniques of visualisation and instrumentation in an anatomically highly confined space with semitransparent tissues are fundamentally different from other anterior segment surgeries, and present even experienced surgeons with a substantial learning curve. Here, we provide practical tips, and review techniques and outcomes of TM bypass and ablation MIGS.

Update on Minimally Invasive Glaucoma Surgery (MIGS) and New Implants

Traditional glaucoma surgery has been challenged by the advent of innovative techniques and new implants in the past few years. There is an increasing demand for safer glaucoma surgery offering patients a timely surgical solution in reducing intraocular pressure (IOP) and improving their quality of life. The new procedures and devices aim to lower IOP with a higher safety profile than fistulating surgery (trabeculectomy/drainage tubes) and are collectively termed “minimally invasive glaucoma surgery (MIGS).” The main advantage of MIGS is that they are nonpenetrating and/or bleb-independent procedures, thus avoiding the major complications of fistulating surgery related to blebs and hypotony. In this review, the clinical results of the latest techniques and devices are presented by their approach, ab interno (trabeculotomy, excimer laser trabeculotomy, trabecular microbypass, suprachoroidal shunt, and intracanalicular scaffold) and ab externo (canaloplasty, Stegmann Canal Expander, suprachoroidal Gold microshunt). The drawback of MIGS is that some of these procedures produce a limited IOP reduction compared to trabeculectomy. Currently, MIGS is performed in glaucoma patients with early to moderate disease and preferably in combination with cataract surgery.

Clinical results of ab interno trabeculotomy using the trabectome for open-angle glaucoma: the Mayo Clinic series in Rochester, Minnesota

PURPOSE

To determine outcomes of ab interno trabeculotomy for treatment of open-angle glaucoma (OAG).

DESIGN

Retrospective interventional single-surgeon, single-center case series.

METHODS

Data were collected from 246 patients undergoing ab interno trabeculotomy between September 1, 2006, and December 1, 2010, with 3 months' follow-up or longer. Kaplan-Meier analysis was performed using Criteria A (postoperative intraocular pressure [IOP] ≤21 mm Hg or ≥20% reduction from preoperative IOP) and Criteria B (IOP ≤18 mm Hg and ≥20% reduction in IOP). Failure included increased glaucoma medications or subsequent surgery. Failure risk factors were identified using Cox proportional hazards ratio (HR).

RESULTS

Of 88 cases of ab interno trabeculotomy-only and 158 cases of ab interno trabeculotomy with cataract extraction, the retention rate was 70% for 1 year and 62% for 2 years. Preoperative mean IOP was 21.6 ± 8.6 mm Hg; the number of glaucoma medications was 3.1 ± 1.1. At 24 months postoperatively, mean IOP was reduced 29% to 15.3 ± 4.6 mm Hg (P < 0.001) and the number of glaucoma medications was reduced 38% to 1.9 ± 1.3 (P < 0.001) with a success rate of 62% (95% CI, 56%-68%) using Criteria A and 22% (95% CI, 16%-29%) using Criteria B. Failure risk factors using Criteria A included primary OAG (HR 3.14, P < 0.01, 95% CI, 1.91-5.17) and past argon laser trabeculoplasty (HR 1.81, P < 0.01, 95% CI, 1.18-2.77). Using Criteria B, the HR for pseudoexfoliative glaucoma was 0.43 (P < 0.01, 95% CI 0.27-0.67). Of the cases, 66 (26.8%) required subsequent surgery on an average of 10 months (2 days to 3.2 years) after ab interno trabeculotomy.

CONCLUSIONS

For criteria involving IOP ≤18 mm Hg, the 24-month survival of ab interno trabeculotomy is low. This surgery is appropriate for patients requiring a target IOP of 21 mm Hg or above.

Trabectome surgery for primary and secondary open angle glaucomas

Purpose

In most forms of open angle glaucoma, the trabecular meshwork is the main barrier for aqueous humor outflow, causing elevated intraocular pressure (IOP). The Trabectome is a minimal invasive device for the surgical treatment of open angle glaucoma, particularly eliminating the juxtacanalicular meshwork. This study was conducted to compare the effectiveness and complication profile among different glaucoma subgroups.

Methods

Single center prospective observational study. There were 557 consecutive eyes of 487 patients included in this study. Trabectome surgery was performed either alone or in combination with cataract surgery. Intraoperative and postoperative complications were documented systematically. Main outcome measures were IOP reduction over time and the preoperative and postoperative number of IOP-lowering medications. Due to subgroup sizes, only data from eyes with primary open angle glaucoma and pseudoexfoliation glaucoma were processed for statistical analysis.

Results

For the 261 eyes classified as primary open angle glaucoma, preoperative IOP was 24 ± 5.5 mmHg (mean ± SD) under 2.1 ± 1.3 IOP-lowering medications. After a mean follow-up of 204 ± 238 days, IOP was reduced to 18 ± 6.1 mmHg, and medication was reduced to 1.2 ± 1.1. For the 173 eyes classified as pseudoexfoliation glaucoma, after a mean follow-up of 200 ± 278 days, IOP was reduced from 25 ± 5.9 mmHg to 18 ± 8.2 mmHg, and medication was reduced from 2.0 ± 1.2 to 1.1 ± 1.1. A Cox proportional hazards model hinted forward superiority of the combined surgery cases (Trabectome + Phaco + intraocular lens) in comparison to Trabectome surgery only in phakic or pseudophakic eyes. No serious complications were observed.

Conclusions

Minimal invasive glaucoma surgery with the Trabectome seems to be safe and effective. The subgroup analysis of different kinds of open angle glaucomas presented in this study may help in first-line patient selection. The lack of ocular surface alterations makes it a valuable addition to glaucoma surgery.

Combined clear cornea phacoemulsification in the treatment of pseudoexfoliative glaucoma associated with cataract: significance of trabecular aspiration and ab interno trabeculectomy

BACKGROUND

In the present study, the effectiveness of combined cataract surgery and ab interno trabeculectomy (Trabectome) in exfoliation glaucoma (PEX) was compared with combined cataract surgery and trabecular aspiration.

METHODS

In this retrospective comparative cohort outcome study, 27 consecutive patients (mean age 73.41 years ± 10.78) in group 1 suffering from visually significant cataract and PEX glaucoma (mean preoperative IOP 23.41 mmHg ± 5.86) were treated with phacoemulsification combined with Trabectome; and 28 consecutive patients (73.83 years ± 8.94) were treated with phacoemulsification combined with trabecular aspiration (mean preoperative IOP 22.22 mmHg ± 6.33). The intraocular pressure (IOP) and the number of antiglaucoma eyedrops before and after surgery were evaluated.

RESULTS

Examinations were performed prior to surgery, 1 day, 6 weeks, 3 months, 6 months, and 1 year after surgery. In both groups there was a statistically significant decrease in postoperative IOP during the whole follow-up period. Comparing the two groups, there was a statistically significant lower IOP in the Trabectome group 1 day (p = 0.019), 6 months (p = 0.025), and 1 year (p = 0.019) after surgery. Between the two groups, there was no statistically significant difference in the number of antiglaucoma eyedrops at any time.

CONCLUSIONS

Both procedures have the ability to significantly lower the postoperative IOP during the first year. However, clear cornea phacoemulsification combined with Trabectome seems to be more effective in IOP reduction in cases of PEX glaucoma associated with cataract.

Influence of prostaglandin analogue on outcome after combined cataract surgery and trabecular aspiration in pseudoexfoliative glaucoma

PURPOSE

The aim of this study was to analyze the postoperative outcome and risk profile after combined clear cornea phacoemulsification and trabecular aspiration in the treatment of pseudoexfoliative glaucoma (PEX) associated with cataract. 


METHODS

In this retrospective study, 69 eyes of 60 patients with visually significant cataract and PEX were treated with small-incision cataract surgery combined with trabecular aspiration. The intraocular pressure (IOP), number of antiglaucoma eyedrops before and after surgery, as well as complications were measured at all postoperative visits (1 day, 7 days, 6 weeks, 6 months, 12 months). 


RESULTS

There was a statistically significant decrease in postoperative IOP during the follow-up 
period. There was no significant difference in the number of medications being used after 6 weeks follow-up. Six months and 12 months after surgery, the number of antiglaucoma eyedrops decreased significantly. Complications were fibrinotic iritis in 4 eyes (5.9%), cystoid macular edema in 3 eyes (4.4%), and hyphema in 1 eye (1.4%). Fibrinotic iritis and macular edema were present in only 37 of 
69 eyes that were treated with prostaglandin analogues.


CONCLUSIONS

Small-incision cataract surgery combined with trabecular aspiration in cases of PEX associated with cataract is effective in IOP reduction over a 1-year follow-up. Prostaglandin analogues may increase the risk of postoperative macular edema and fibrinotic iritis. Preoperative medication exchange may be considered.

Preclinical investigation of ab interno trabeculectomy using a novel dual-blade device

PURPOSE

To evaluate the effects of a novel ab interno trabeculectomy device on human trabecular meshwork (TM).

DESIGN

Laboratory evaluation.

METHODS

The TM from human cadaveric corneal rim tissue was incised using 3 instruments: (1) novel dual-blade device; (2) microvitreoretinal (MVR) blade; and (3) Trabectome. Tissue samples underwent histologic processing and comparative analyses. Subsequently, human eye perfusion studies were performed to evaluate intraocular pressure (IOP)-lowering effects of each device. Main outcome measures were degree of TM removal by histology and IOP in a perfusion model.

RESULTS

The MVR blade exhibited minimal removal of TM and obvious injury to the adjacent sclera. The Trabectome removed a large portion of the central TM, but leaflets of residual tissue remained and thermal injury was noted in all samples. The dual-blade device achieved a more complete removal of TM without injury to surrounding tissues. All devices resulted in statistically significant lowering of IOP during perfusion model studies. MVR blade treatment across 170.0 ± 14.1 degrees of TM resulted in a decrease of IOP from 18.5 ± 1.9 mm Hg to 12.8 ± 2.2 mm Hg (P < .01). Trabectome treatment across 117.5 ± 12.6 degrees resulted in a decrease of IOP from 18.8 ± 1.7 mm Hg to 11.3 ± 1.0 mm Hg (P < .01). Dual-blade device treatment across 157.5 ± 26.3 degrees resulted in a decrease of IOP from 18.3 ± 3.0 mm Hg to 11.0 ± 2.2 mm Hg (P < .01).

CONCLUSIONS

The novel dual-blade device demonstrated a more complete removal of TM without residual TM leaflets or damage to surrounding tissues and significantly reduced IOP in a human eye perfusion model.