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Anita Vin, Joanne C Wen, Sandra Stinnett, Leon W Herndon; The effect of scheduled ripcord removal on the outcomes of Baerveldt 350 implants. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2011.
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Spontaneous opening of a Baerveldt glaucoma implant with dissolution of the ligating suture at 6 weeks can lead to a sudden decrease in intraocular pressure (IOP), which can be associated with visually debilitating complications. Many surgeons place a suture, called a ripcord, in the lumen of the implant at the time of surgery. It is unknown how complication rates of placement of a Baerveldt implant are affected by spontaneous tube opening versus scheduled opening by ripcord removal in clinic. We hypothesized that the scheduled removal of the ripcord at post-operative week 3 would allow for a more controlled reduction in intraocular pressure and be associated with fewer complications as compared to spontaneous opening of the tube.
In this randomized prospective study, 20 consecutive patients with medically uncontrolled glaucoma were consented to receive a superotemporal Baerveldt 350 implant. Subjects were randomized to scheduled ripcord removal with viscoelastic placement in the anterior chamber at week 3 following surgery versus no ripcord removal. Follow-up was done on a standardized schedule; each visit, visual acuity, IOP, and slit lamp biomicroscopy were performed. Complications of hypotony such as shallowing of the anterior chamber, choroidal effusion, or suprachoroidal hemorrhage were reported.
Of the 20 study subjects, 10 were randomized to observation, 10 to ripcord removal. Complications of hypotony were not noted in the observation group; in the ripcord removal group 2 patients experienced hypotony (IOP ≤ 5), and 1 developed choroidal effusions. IOP was not statistically different between the two groups following ripcord removal at most visits although surprisingly at 3 months the ripcord removal group was found to have statistically higher IOP as compared to the removal group (p = 0.031, Wilcoxon rank sum test). This difference did not remain at the 6 month follow-up mark. Visual acuity was also not found to be statistically significantly different between the two groups.
Our results do not support our original hypothesis. We found no statistically significant improvement in IOP or visual acuity at 6 months with scheduled ripcord removal. Additionally, there were complications of hypotony within the ripcord removal group while there were no such complications in the observation group. A larger sample size and longer follow-up would help to corroborate these findings.
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