Outcomes of Trabeculectomy at Kenyatta National Hospital and University of Nairobi: a Retrospective Case Series

Abstract

Trabeculectomy is the commonest glaucoma surgery done at Kenyatta National Hospital (KNH) and University of Nairobi (UON) School of dental sciences. Few studies have been done in Kenya to assess the outcomes of trabeculectomy. So this study aimed to assess the outcomes in order to provide useful information that will further be used for providing recommendation pertaining management of patients undergoing trabeculectomy. Study Objective To assess the outcome of trabeculectomy surgeries done at KNH and University of Nairobi, its complications and need for additional anti-glaucoma medication or glaucoma surgery. Study Design Retrospective case series Materials and Methods This was retrospective hospital-based case series that aimed to assess the outcomes of trabeculectomy surgeries done at KNH main theatre, UON School of dental sciences theatre and the patients’ were followed up at eye clinic at KNH over the study period. The main outcome measures were IOP, CDR and vision. Records of patients done trabeculectomy from 1st January 2006 to 30th December 2015 were retrieved from the hospital records. The files were consecutively selected and reviewed. The relevant information was entered in a pre-designed questionnaire. Data Management Data was entered in a coded questionnaire and then entered in MS Excel spread sheet, which was then be cleaned and verified to ensure consistency. Data analysis was done using SPSS computer software. Results: A total of 149 records were reviewed. The male to female ratio was 2:1.Most patients (84.1%) were 50 years of age. Mean age was 60.8 years with a range of 18-81 years. Most (94.7%) of patients had TET in one eye that met the inclusion criteria .The mean pre-operation IOP was 25.4 ± 6.17 mmHg with a range of 14-63mmHg. All eyes were on anti-glaucoma medications before surgery, with the majority being on 2 or more drugs in the pre-

operative period (85.5%) with a mean of 2.2 ± 0.69. 96% of eyes being on a beta Beta-blockers. Failed medical treatment was the most common indication of trabeculectomy at 58.4%. Majority of TET were done with anti-fibrotic agents (90.6%), of which the most commonly used was MMC (80.5%). There was a statistically significant reduction in the mean IOP after surgery throughout the follow-up period. On the first day after surgery the mean intraocular pressure reduced to 11mmHg increasing to a mean of 16mmHg at year 2 from a mean IOP of 24mmHg before surgery. 76% and 52% achieved qualified and complete success respectively at year 2. At final follow-up visit 17% had failed TET. Mean CDR was 0.9 and Vision was 0.32 logmar equivalent and both were maintained during the follow-up period. Mean number of anti-glaucoma drugs decreased from 2.2 ± 0.69 in pre-operative period to 0.54 ± 0.88 at 2years follow-up visit. Hypotony was the most common early complication seen in 24 eyes (16.1%). The most common late complications was bleb fibrosis, seen in 31 eyes (20.8%). The most serious complications were suprachoroidal haemorrhage (1 eye) and blebitis (1 eye). Needling was the most intervention done for the complications. Most of TET that failed had bleb fibrosis. Conclusion: Trabeculectomy is adequate in controlling IOP up to a period of 2years after surgery however there is no effect on change of CDR after surgery and has limited effect in vision change. Use of anti-glaucoma medications is significantly reduced after TET. Bleb fibrosis and encapsulation forms the greatest risk factor for surgical failure in the long term. Patient follow-up drop-out possess a challenge in management post TET. Recommendation: Trabeculectomy is a safe and effective procedure in controlling IOP. Patients should be educated to ensure good compliance to medications and to follow-up appointments. Conduct a prospective study with a longer follow-up period to assess the long-term success rates of trabeculectomy.