Abstract
Purpose: :
A venting slit suture modification of glaucoma drainage implants to provide early intraocular pressure (IOP) control was previously reported, but is not often utilized. The purpose of this study was to evaluate this novel approach to see if it provided a reliable solution to the early post-operative complications seen with glaucoma drainage implants.
Methods: :
We conducted a retrospective study of 14 eyes of 13 patients with high preoperative IOP on maximum medical therapy. 7 eyes were implanted with the Baerveldt 350 implant, 5 with the Baerveldt 250, and 2 with the Molteno 3. All of the tubes were completely occluded with a surrounding 7-0 Vicryl Suture. 7 implants had an intralumenal 5-0 Nylon suture. Occlusion was confirmed by attempted irrigation of the tube. The tube was then inserted into the anterior chamber and confirmation of no flow around the inserted tube was achieved. The venting slit suture was created by using a 10-0 nylon suture with a CU-8 needle and passing it through the limbus from the corneal side, through the tube, and then back out through the limbus to the corneal surface. The venting slit suture was then checked for egress of fluid and to make sure the eye did not become too hypotonic.
Results: :
We studied the immediate postop effect of the venting slit suture itself and not the long-term efficacy of the implant, and therefore evaluated only at 1 day, 2 weeks, 3 weeks, 1 month and 2 months post-operatively. Mean (±SD) preoperative IOP was 32.2 ± 5.98 mm Hg (range 19-42) on Mean medications of 3.36 ± 1.49 (range 1-6). At day 1 IOP was 17.57 ± 14.67 (5-64) on 0.07 ± .27 (0-1) medicines. At week 2 IOP was 15.57 ±5.39 (5-23) on 0.5 ± 1.16 (0-4) medicines. At week 3 IOP was 21.21 ± 8.69 (10-45) on 0.71 ± 1.33 (0-4) medicines. At week 4 IOP was 16.31 ± 7.69 (4-28) on 1.29 ± 1.68 (0-4) medicines. At 2 months IOP was 25.83 ± 14.99 (4-56) on 0.75 ± 1.29 (0-4) medicines. One patient became hypotonic on day 1 post-op (5 mmHg) and the Venting Slit Suture was removed. The pressure was then measured at 23-45 mm Hg at the subsequent time points.
Conclusions: :
In occluded glaucoma drainage implants a venting slit suture provides safe and effective short-term IOP control on fewer medications than preoperatively. This study also shows that the IOP lowering effects of the suture is reversible which is important in the rare cases of postop hypotony. Overall, the use of venting slit sutures in glaucoma drainage implants provides a reliable alternative to previous tube modifications as there were no severe hypertension cases and the one hypotonic incidence was easily reversed.
Keywords: intraocular pressure • outflow: trabecular meshwork • wound healing