Abstract
Purpose: :
To evaluate the success rate of bleb needling and identify risk factors for failure.
Methods: :
Consecutive patients undergoing their first bleb needling during a period of January 2007- May 2009 were eligible. Patients with less than 1-year follow up were excluded. The primary outcome measure was the absolute and qualified success at the last follow up visit. Absolute success was defined as a reduction of intraocular pressure (IOP) to less than 18mmHg with at least a 20% IOP reduction from pre-needling IOP, with equal or less number of IOP medications compared to before needling, and without further glaucoma surgery or devastating complications. Qualified success allowed for an increased number of IOP medications. The secondary outcome was the time to failure. Statistical analysis included Kaplan-Meier plots and a Cox regression analysis.
Results: :
96 eyes of 86 patients were enrolled in the study. 9 eyes were excluded due to inadequate follow-up. The mean follow-up for the 87 eyes of 80 patients included was 22.5 ± 9.9 months. Subconjunctival mitomycin C (MMC) (0.02mg) was used in 83 cases (95.4%) and 5-FU (10mg) in 2 cases (2.3%). The mean time between trabeculectomy surgery and the needling procedure was 16.2 ± 34.4 months (range 25 days - 17 years). The mean IOP pre-needling and at the final visit was 21.7±6.7 and 15.2 ± 6.6 mmHg respectively (p<0.001). Repeat needling was performed in 23 eyes (26.4%) and additional glaucoma surgery in 15 eyes(17.2%). Absolute and qualified success at the last follow-up visit was 51.7% and 59.8% respectively. The average time to failure was 5.4±8.2 months. Earlier failure was associated with elevated IOP pre-needling as a continuous variable (Hazard Ratio 1.06 95% CI 1.01-1.11). Time interval between surgery and needling, primary diagnosis, previous laser surgery, age, and lens status were not associated with time to failure. Transient hypotony (IOP < 6mmHg) occurred in 14 eyes. Six eyes had choroidals and one had a suprachoroidal hemorrhage.
Conclusions: :
Bleb needling is successful in reducing IOP, has a low rate of complications, and is effective in decreasing the need for further glaucoma surgery. The success is not altered by the length of time since trabeculectomy.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • clinical (human) or epidemiologic studies: systems/equipment/techniques • wound healing