Outcomes of Glaucoma Drainage Device Implantation and Trabeculectomy With Mitomycin C in Glaucoma Secondary to Aniridia





Purpose


To compare the outcomes of Aurolab aqueous drainage implant (AADI; Aurolab) placement and trabeculectomy with mitomycin C (MMC) in patients with glaucoma secondary to aniridia.


Design


Retrospective comparative interventional case series.


Methods


This study included patients with congenital aniridia who underwent AADI implantation or trabeculectomy with MMC. Surgical failure was defined as IOP > 21 mm Hg or reduced <20% from baseline, IOP ≤ 5 mm Hg, reoperation for glaucoma or a complication, or loss of light perception vision.


Results


A total of 30 eyes of 30 patients underwent surgical treatment, including 18 eyes that received an AADI and 12 eyes that had a trabeculectomy with MMC. The cumulative probability of failure at 2 years was 11.1% (95% CI = 2.9%-37.6%) in the AADI group and 58.3% (95% CI = 33.5%-84.8%) in the trabeculectomy group ( P = .05, log-rank). At 2 years, IOP (mean ± SD) was 14.1 ± 2.8 mm Hg in the AADI group and 19.6 ± 6.6 mm Hg in the trabeculectomy group ( P = .02), and the number of glaucoma medications was 1.7 ± 0.9 in the AADI group and 2.2 ± 0.8 in the trabeculectomy group ( P = .25). Surgical complications developed in 1 patient in each treatment group ( P = .65). Cataract surgery was performed in 5 (42%) patients in the trabeculectomy group and no patients in the AADI group ( P = .01).


Conclusions


Placement of an AADI resulted in lower IOP and a higher rate of surgical success compared to trabeculectomy with MMC in eyes with glaucoma associated with aniridia. Cataract extraction was more frequently required after trabeculectomy with MMC than AADI implantation.


G laucoma or ocular hypertension associated with aniridia has been reported to occur in 6%-75% of patients and generally develops during the first 2 decades of life. Intraocular pressure (IOP) elevation has been variably attributed to angle closure owing to progressive anterior rotation of the rudimentary iris, cleavage abnormalities of anterior chamber angle, and dysgenesis of the Schlemm canal. Glaucoma associated with aniridia is frequently refractory to medical management, with most patients requiring incisional surgery.


Goniosurgery, trabeculotomy, trabeculectomy, glaucoma drainage devices (GDDs), and cyclodestructive procedures have all been used to manage glaucoma association with aniridia, with variable success rates. Trabeculectomy is the most commonly performed primary surgical procedure, but GDDs have been increasingly used as an alternative. , , The Aurolab aqueous drainage implant (AADI; Aurolab, Madurai, India) is a relatively new, cost-effective shunt resembling the Baerveldt glaucoma implant, which has shown efficacy and safety similar to other GDDs. This study compares the efficacy and safety of AADI placement and trabeculectomy with mitomycin C (MMC) in patients with glaucoma associated with aniridia.


Methods


This retrospective, comparative case series was approved by the Institutional Ethics Committee of the Aravind Hospital, Madurai, India (RET201900331), and conformed to the ethical tenets of the Declaration of Helsinki. Medical records of patients who underwent trabeculectomy with MMC or the nonvalved AADI implantation for glaucoma secondary to congenital aniridia between April 2005 and February 2015 were included in the study. In patients who underwent bilateral surgery, the eye operated first was analyzed. Patients with follow-up of less than 12 months were not included in the analysis unless they reached a failure endpoint. Patients with previous glaucoma surgery or those who did not receive MMC with trabeculectomy were also excluded.


The data extracted from the medical record included age at diagnosis of glaucoma, age at surgical treatment, sex, family history of aniridia, laterality, history of previous intraocular surgeries, lens status, and any concomitant ocular disorders. Best-corrected visual acuity (BCVA), IOP, glaucoma medications, and cup-to-disc ratio were recorded at baseline and 1, 3, 6, and 12 months after surgery, as well as annually thereafter. Also noted were the duration of follow-up, complications, and reoperations.


Surgical Procedures


Aurolab Aqueous Drainage Implant implantation


The same surgical procedure was used for all patients, for implantation of the 350 mm 2 AADI, and all surgeries were performed by the same surgeon (G.V.P.). The surgical technique and the postoperative regimen have been described in detail elsewhere.


Trabeculectomy with mitomycin C


A fornix-based conjunctival flap was raised as per the standard technique, and a triangular partial-thickness scleral flap was dissected. This was followed by application of freshly prepared mitomycin C (MMC) 0.2 mg/mL using saturated cellulose sponges for 2 minutes. A copious amount of balanced salt solution was used to irrigate the surgical site after the sponges were removed. A paracentesis was performed, followed by sclerostomy using a Kelly punch and a broad-based peripheral iridectomy. The scleral flap was then sutured with 10-0 nylon suture (Aurolab, Madurai, India), and the conjunctiva was closed with 8-0 polyglactin suture (braided coated polyglactin 910 violet; Ethicon, Johnson & Johnson Ltd, Mumbai, India). Postoperatively topical steroid drops were used for 12 weeks in a tapering dose, a topical antibiotic 4 times daily for 2 weeks, and cycloplegic eye drops once a day for a month.


Primary Outcome Measure


Surgical failure was defined as IOP > 21 mm Hg or reduced <20% from baseline at 2 consecutive follow-up visits after 3 months, IOP ≤ 5 mm Hg on 2 consecutive follow-up visits after 3 months, reoperation for glaucoma or a complication, or loss of light perception vision. Eyes that had not failed by these criteria were categorized as successes. Eye that achieved success without supplemental glaucoma medications were classified as complete successes, while eyes requiring glaucoma medications were considered qualified successes.


Statistical Analysis


All continuous variables were described as mean with standard deviation (SD) or median with interquartile range (IQR), and categorical variables were described as proportions (n, %). Age at surgery, baseline IOP, and cup-to-disc ratio were analyzed using independent t test; baseline BCVA was presented as median (IQR) and analyzed using the Mann-Whitney U test; categorical variables were analyzed using a χ 2 test to ascertain the comparability of the 2 groups.


Data were presented as mean (SD) for IOP and IOP glaucoma medications were analyzed using paired t test; median (IQR) for logMAR visual acuity (VA) was analyzed postoperatively using Wilcoxon signed rank test. Comparison of IOP between groups was analyzed using independent t test and Mann-Whitney U test was used to compare medications and VA between groups.


Fisher exact test was used to assess difference in the proportion of patients with postoperative complications and reoperations between treatment groups. The Kaplan-Meier plot for cumulative failure at various time points between trabeculectomy with MMC and AADI was also computed for each treatment group. A P value < .05 was considered statistically significant.


Results


A total of 30 eyes of 30 patients with glaucoma secondary to aniridia underwent surgical treatment, including 12 eyes that had a trabeculectomy with MMC and 18 eyes that had AADI implantation. Six additional patients were identified but were excluded from the study because they had less than 12 months of follow-up. The baseline demographic and clinical features of the study population are shown in Table 1 . There were no significant differences in baseline characteristics such as age, sex, IOP, BCVA, cup-to-disc ratio, lens status, or concomitant ocular disorders in the trabeculectomy and AADI groups.



Table 1

Baseline Demographics and Clinical Characteristics of Study Patients
































































Variable Trabeculectomy Group (N = 12) AADI Group (N = 18) P Value
Age at diagnosis of glaucoma (years), mean ± SD 11.7 ± 12.3 15.7 ± 9.5 .19
Age at surgery (years) 17.2 ± 13.2 19.7 ± 10.2 .57
Sex (male), n (%) 8 (66.7) 14 (77.8) .68
% Right eye 6 (50%) 9 (50%) .99
IOP (mmHg), mean ± SD 27.2 ± 10.9 32.5 ± 11.4 .21
LogMAR BCVA, mean ± SD 1.17±0.7 1.09±0.6 .36
Cup-to-disc ratio, mean ± SD 0.76 ± 0.1 0.78 ± 0.1 .58
Number of eyes with prior ocular surgeries, n (%) 4 (33) 5 (28) .86
Family history of aniridia, n (%) 0 1 (5.6) >.99
Concomitant ocular disorders, n (%)
LSCD
Lens coloboma
Lens subluxation
Microcornea
Megalocornea
High myopia
Retinal detachment
Foveal hypoplasia
Nystagmus

2 (17)
0
1 (8)
4 (33)
3 (25)
1 (8)
0
0
9 (75)

6 (33)
2 (11)
5 (28)
1 (5.6)
0
6 (33)
1 (5.6)
2 (11)
13 (72)

.42
.50
.36
.13
.05
.19
>.99
.50
.87
Lens status, n (%)
Clear
Cataract
Aphakia
Pseudophakia

7 (58)
2 (16)
0
3 (25)

11 (61)
3 (17)
1 (5.6)
3 (17)
.92

AADI = Aurolab aqueous drainage implant; BCVA = best-corrected visual acuity; IOP = intraocular pressure; LogMAR = logarithm of the minimum angle of resolution; LSCD = limbal stem cell deficiency.


Three of 12 eyes (25%) in the trabeculectomy group had previous cataract extraction with PCIOL implantation. Four of 18 eyes (22%) in the AADI group had undergone previous cataract surgery. Of those 4 eyes, 3 (75%) had PCIOL implantation, including 2 (50%) that also underwent primary posterior capsulorrhexis with anterior vitrectomy. One eye underwent simultaneous pars plana lensectomy along with a pars plana vitrectomy and was left aphakic.


Comparisons of IOP, VA, and glaucoma medications at baseline and across follow-up between the trabeculectomy and AADI groups are shown in Table 2 . Mean postoperative IOP was significantly lower than baseline in the trabeculectomy and AADI groups throughout the first 2 years of follow-up. However, IOP was not significantly different from the preoperative level at 3 years and 4 years postoperatively in either treatment group. It is noteworthy that a majority of patients were seen for 2 years after surgery, but follow-up was limited thereafter, especially in the AADI group. The mean number of glaucoma medications was similar to the preoperative level in both treatment groups throughout 4 years of follow-up. There was also no significant difference in logMAR VA from baseline in either treatment group, except for an improvement in VA in the AADI group at 3 months and 6 months.



Table 2

Intraocular Pressure, Glaucoma Medications, and Visual Acuity at Baseline and Follow-up








































































Trabeculectomy Group (N = 12) AADI Group (N = 18) P Value b
Mean ± SD P Value a Mean ± SD P Value a
Baseline
IOP
Glaucoma medications
LogMAR VA
n

27.2 ± 10.9
1.7 ± 0.9
1.17 ± 0.7
12

̶
̶
̶

32.5 ± 11.4
1.8 ± 0.9
1.09 ± 0.6
18

̶
̶
̶

.21
.68
.36
Month 1
IOP
Glaucoma medications
LogMAR VA
n

19.3 ± 5.7
1.3 ± 0.9
1.1 ± 0.7
12

.03 *
.20
.57

20.5 ± 7.7
1.9 ± 0.8
1.1 ± 0.6
18

<.01 *
.89
.49

.64
.04*
.53
Month 3
IOP
Glaucoma medications
LogMAR VA
n

15.4 ± 3.6
1.7 ± 0.6
1.1 ± 0.7
12

.01*
.90
.50

14.3 ± 5.9
1.3 ± 0.7
1.0 ± 0.6
18

<.01*
.08
.03

.56
.22
.37
Month 6
IOP
Glaucoma medications
LogMAR VA
n

18.3 ± 4.0
1.7 ± 0.6
1.1 ± 0.7
12

.01
.71
.50

13.4 ± 3.5
1.4 ± 0.6
0.8 ± 0.6
15

<.01
.16
.02

.01*
.20
.10
Year 1
IOP
Glaucoma medications
LogMAR VA
n

18.2 ± 5.2
1.8 ± 0.6
1.0 ± 0.7
12

.01
.46
.31

13.2 ± 2.7
1.6 ± 0.6
1.0 ± 0.6
18

<.01
.55
.05

.01*
.30
.87
Year 2
IOP
Glaucoma medications
LogMAR VA
n

19.6 ± 6.6
2.2 ± 0.8
1.1 ± 0.7
12

.02
.17
.61

14.1 ± 2.8
1.7 ± 0.9
0.9 ± 0.5
10

.01
.71
.08

.02*
.25
.47
Year 3
IOP
Glaucoma medications
LogMAR VA
n

20.5 ± 5.5
2.3 ± 0.7
0.9 ± 0.7
10

.18
.10
.40

14.4 ± 3.2
1.4 ± 1.1
0.6 ± 0.2
5

.05
.27
.09

.04*
.11
.16
Year 4
IOP
Glaucoma medications
LogMAR VA
n

22.3 ± 7.3
2.4 ± 0.9
0.84 ± 0.6
9

.74
.06
.46

17.0 ± 2.8
0.5 ± 0.7
0.84 ± 0.3
2

.18
.18
.32

.35
.04*
.87

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Jul 10, 2021 | Posted by in OPHTHALMOLOGY | Comments Off on Outcomes of Glaucoma Drainage Device Implantation and Trabeculectomy With Mitomycin C in Glaucoma Secondary to Aniridia

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