Combined trabeculotomy-trabeculectomy versus Ahmed valve implantation for refractory primary congenital glaucoma in Egyptian patients: a long-term follow-up

Abstract

Introduction: Primary congenital glaucoma (PCG) is the most common type of glaucoma in pediatric patients. The aim of this study was to compare the effectiveness of combined trabeculotomy-trabeculectomy versus Ahmed valve implantation for cases of PCG refractory to traditional incisional angle surgery (goniotomy and trabeculotomy) in the Egyptian population.

Methods: The study was conducted in the Glaucoma Clinic of the Research Institute of Ophthalmology (Egypt). The study included 66 eyes of 66 patients (in two groups) with advanced PCG who had previous failed goniotomy, trabeculotomy, or both. Group 1 included 33 patients who underwent trabeculotomy-trabeculectomy procedures; group 2 included 33 patients who underwent FP 8 Ahmed valve implantation. The main outcome measures were intraocular pressure (IOP) reduction, corneal diameter, and axial length stability in both groups. Secondary outcome measures included detection of complications in both groups.

Results: The average ages of the patients were 13.5 ± 3.9 months and 15.3 ± 5.8 months in groups 1 and 2, respectively. Ten patients (30.3%) in group 1 and 9 patients (27.3%) in group 2 had family histories of PCG. Positive consanguinity was present in 26 patients (78.8%) in group 1 and in 27 patients (81.8%) in group 2. In group 1, the mean intraocular pressure (IOP) value decreased from 33.6 ± 3.4 mmHg preoperatively to 13.8 ± 0.6, 16.9 ± 1.5, 18.2 ± 2.5, 19.8 ± 3.6, and 20.2 ± 3.1 mmHg in the first postoperative month and after years 1, 2, 3, and 4, respectively (p < 0.001). In group 2, the mean IOP value decreased from 33.4 ± 4.5 mmHg preoperatively to 13.3 ± 1.1, 16.3 ± 1.6, 18.1 ± 1.0, 19.1 ± 3.5, and 19.9 ± 3.7 mmHg in the first postoperative month and after years 1, 2, 3, and 4, respectively (p < 0.001). The average number of medications decreased from 2.2 ± 0.4 preoperatively to 1.8 ± 0.4 postoperatively in group 1, while it decreased from 2.1 ± 0.4 preoperatively to 1.9 ± 0.3 postoperatively in group 2. The success rate in group 1 was 97, 91, 76, and 61% in years 1, 2, 3, and 4, respectively, whereas the success rate in group 2 was 97, 93, 81, and 66% in years 1, 2, 3, and 4, respectively.

Conclusion: Both procedures, i.e., combined trabeculotomy-trabeculectomy and Ahmed valve implantation are suitable options in advanced PCG with failed trabeculotomy and goniotomy. Ahmed valve implanation has a better long-term survival, but trabeculotomy-trabeculectomy provides a second chance for surgical intervention.

Keywords: Ahmed valve implantation; buphthalmos; intraocular pressure; primary congenital glaucoma; trabeculotomy-trabeculectomy.

Figure 1

Postoperative IOP in both groups during the follow-up period