Results of Trabeculectomy Using Modified Scleral Flap Suture Technique in Comparison with Standard Trabeculectomy

Jung Hyun Ahn; Moo Hwan Jang; Jong-Hoon Lee

doi:10.3341/jkos.2008.49.6.925

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Ahn, Jang, and Lee: Results of Trabeculectomy Using Modified Scleral Flap Suture Technique in Comparison with Standard Trabeculectomy

Original Article

J Korean Ophthalmol Soc 2008;49(6):925-934.

Published online: 8 September 2008

DOI: https://doi.org/10.3341/jkos.2008.49.6.925

Results of Trabeculectomy Using Modified Scleral Flap Suture Technique in Comparison with Standard Trabeculectomy

Jung Hyun Ahn, M.D., Moo Hwan Jang, M.D., Jong-Hoon Lee, M.D.

Department of Ophthalmology, Dankook University College of Medicine, Cheonan, Korea

Address reprint requests to Jong-Hoon Lee, M.D. Department of Ophthalmology, Dankook University College of Medicine #San 16-5 Anseo-dong, Cheonan, Chungnam 330-714, Korea Tel: 82-41-550-6377, Fax: 82-41-561-0137, E-mail: jonglee@dankook.ac.kr

5 February 2008 Accepted 26 November 2007

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To evaluate the efficacy of trabeculectomy using modified scleral flap suture technique

Methods

We retrospectively reviewed the medical records of 52 patients (55 eyes) who had undergone trabeculectomy from January 2003 to January 2007. Standard trabeculectomy was performed for 29 eyes of 27 patients, modified trabeculectomy for 26 eyes of 25 patients. We changed suture site of scleral flap corner about 1mm medially from original site and added tight suture to both lateral margins of scleral flap to prevent overflow in modified group. In both groups, most of patients were injected 0.1 ml of 0.02 mg/ml mitomycin-C (MMC) subconjunctivally and the others 0.1 ml of 0.04 mg/ml MMC. We evaluated intraocular pressure (IOP), complication, morphology of filtering bleb, cumulative success rates.

Results

Argon laser suturelysis was performed postoperatively in about half cases of both groups. The IOPs of modified group were consistently lower than those of standard group for 24 months except postoperative 1 day and 1 week. There was a significant difference of IOP at postoperative 2 months and 12 months ( p<0.05). No significant difference of complications was found between two groups. The diffuse bleb with microcyst was found in 19 eyes (73%) of modified group and 17 eyes (59%) of standard group. From Kaplan-Meier survival analysis, cumulative success rates of modified group were higher than those of standard group ( p<0.05).

Conclusions

Trabeculectomy using modified scleral flap suture appears to give better IOP control than standard trabeculectomy.

Keywords: Argon laser suture lysis, Mitomycin-C (MMC), Modified trabeculectomy

References

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Figure 1.

Techniques of scleral flap suture. (A) Modified trabeculectomy. (B) Standard trabeculectomy. In modified trabeculectomy, suture site of scleral flap corner was changed 1 mm inside from the original location and 4 scleral flap sutures were used. In standard trabeculectomy, two to four scleral flap sutures were used according to aqueous flow and anterior chamber depth.

Figure 2.

Morphologies of conjunctival blebs. (A) shows a diffuse bleb with microcystic change and (B) shows an ischemic bleb. (C) and (D) show a flat bleb and an encapsulated bleb, respectively.

Figure 3.

The changes of intraocular pressure (IOP) after trabeculectomy. The asterisk (＊) indicates the point where there was a statistically significant difference of IOP level between the two groups ( p<0.05, Student’s t-test).

Figure 4.

The changes of intraocular pressure (IOP) after argon laser suture lysis. In modified trabeculectomy group, the asterisks (＊) indicate points where there was a statistically significant difference of IOP level compared with IOP just before argon laser suture lysis ( p<0.05, Wilcoxon signed rank test). In standard trabeculectomy group, the cross mark (+) indicates point where there was a statistically significant difference of IOP level compared with IOP just before argon laser suture lysis ( p<0.05, Wilcoxon signed rank test).

Figure 5.

Postoperative cumulative survival rate of two surgical groups (Kaplan-Meier survival curve). (A) Success was defined as intraocular pressure (IOP) under 18 mmHg with less than two ocular hypotensive drugs ( p<0.05, log rank test). (B) Success was defined as 1) IOP under 21 mmHg and postoperative IOP reduction exceeded 20% of preoperative IOP, if no use of ocular hypotensive drug 2) IOP under 21 mmHg and postoperative IOP reduction exceeded 30% of preoperative IOP and reduction in the number of ocular hypotensive drugs after trabeculectomy, if use of ocular hypotensive drugs ( p<0.05, log rank test). There are statistically significant differences in both of the two success criteria.

Figure 6.

After modified trabeculectomy, there were dome-shaped conjunctival blebs in 14 eyes (54%) of 26 eyes.

Table 1.

Comparisons of preoperative characteristics of two groups

	Modified	Standard	p-value
Number of eyes	26	29
Age (years, mean±SD)	61.9±11.6	60.3±13.5	0.645^*
Sex (Male/Female)	10/16	13/16	0.785^†
Duration of follow-up (months, mean±SD)	16.8±5.3	19.9±6.1	0.051^*
Preoperative IOP (mm Hg)	30.8±8.8	33.2±9.7	0.338^*
Number of preoperative medications	3.4±1.1	2.9±0.9	0.106^*
Previous filtering surgery	4	1	0.178^†
Other previous intraocular surgery	1	2	1.000^†

^* Student’s t-test

^† Fisher's exact test.

Table 2.

Glaucoma types of two groups No. of eyes (%)

	Modified	Standard
POAG	9 (34%)	10 (34%)
CACG	11 (42%)	10 (34%)
AACG	2 (8%)	4 (14%)
PXG	2 (8%)	1 (4%)
Secondary glaucoma	2 (8%)	4 (14%)

POAG=primary open‐ angle glaucoma; CACG=chronic angle closure glaucoma; AACG=acute angle closure glaucoma; PXG=pseudoexfoliative glaucoma.

Table 3.

Pre- and postoperative intraocular pressure (mmHg)

	Modified	Standard	p-value*
Preoperative	30.8±8.8	33.2±9.7	0.338
Postoperative
1 day	13.3±9.8	10.5±6.6	0.224
1 week	10.4±5.2	10.0±5.3	0.748
1 month	11.1±4.2	12.3±5.8	0.403
2 months	10.1±3.8	12.9±5.3	<0.05
4 months	11.0±3.8	13.1±5.1	0.098
6 months	11.3±4.1	12.6±3.6	0.214
12 months	9.8±3.5	13.2±4.6	<0.05
18 months	11.0±4.1	12.9±4.5	0.289
24 months	10.7±3.5	12.7±4.0	0.228

^* Student’s t-test.

Table 4.

Pre- and postoperative numbers of glaucoma medications

	Modified	Standard	p-value^*
Preoperative	3.4±1.1	2.9±0.9	0.106
Postoperative
6 months	0.2±0.5	0.5±0.7	0.149
12 months	0.1±0.3	0.5±0.8	<0.05
18 months	0.2±0.4	0.7±1.0	<0.05
24 months	0.2±0.4	0.9±1.3	<0.05

^* Student’s t-test.

Table 5.

Distributions of conjunctival blebs No. of eyes (%)

Conjunctival bleb	Modified	Standard
Diffuse bleb with microcystic change	19 (73%)	17 (59%)
Ischemic	1 (4%)	4 (14%)
Flat	5 (19%)	8 (27%)
Encapsulated (Tenon cyst)	1 (4%)	0 (0%)

Table 6.

Postoperative complications No. of eyes

Complications	Modified	Standard	p-value^†
Early ( <1 month postoperatively)
Wound leak	0	2	0.492
Shallow anterior chamber	5	10	0.239
Transient hypotony^*	3	6	0.475
Choroidal detachment	2	1	0.598
Transient hyphema	3	3	1.000
Late ( > 1 month postoperatively)
Late bleb leak	0	1	1.000
Persistent hypotony^*	2	3	1.000
Cataract operation	4	5	1.000

^* Intraocular pressure ≤ 5 mmHg

^† Fisher’s exact test.

Table 7.

Postoperative additional procedures

		No. of eyes (%)
	Modified	Standard
Argon laser suture lysis	12 (46%)	14 (48%)
Needle revision	2 (8%)	5 (17%)
Re‐ filtering surgery	0 (0%)	2 (7%)

Table 8.

The changes of intraocular pressure before and after argon laser suture lysis

	Modified	Standard	P-value^*
Number of eyes	12	14
Time (days)^†	8.7±6.7	10.9±9.5	0.705
Intraocular pressure (mmHg)
Before argon laser suture lysis	21.8±13.3	17.3±6.3	0.527
After argon laser suture lysis
1 week (p-value^‡)	11.3±5.5 (0.016^§)	13.0±4.0 (0.013^§)	0.274
1 month	11.3±4.7 (0.028^§)	13.7±6.6 (0.176)	0.297
2 months	11.2±3.8 (0.023^§)	12.6±3.8 (0.123)	0.212
3 months	11.2±3.2 (0.028^§)	12.4±3.9 (0.059)	0.320
4 months	11.7±3.0 (0.028^§)	15.0±5.0 (0.387)	0.450
5 months	12.0±2.9 (0.045^§)	13.2±2.8 (0.202)	0.397
6 months	11.7±4.2 (0.013^§)	13.7±3.1 (0.169)	0.198

^† At the time of argon laser suture lysis after trabeculectomy

^* Mann-Whitney U test; with IOP just before argon laser suture lysis

^‡ Wilcoxon signed rank test, compared

^§ Statistically significant ( P<0.05), Wilcoxon signed rank test.

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