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[The failure causes of non-penetrating trabecular surgery and reoperation].

OBJECTIVE
To study the failure causes of non-penetrating trabecular surgery (NPTS) with SKGeL (a hyaluronic acid biological gel) implant and the surgical method of reoperation.


METHODS
Repeated operation with mitomycin (MMC) through the initial surgical site was performed on 13 failure cases (13 eyes) that had undergone NPTS with SKGeL implant. The blockage of filtration tract was removed and the anterior chamber was intact during the surgery. All of these cases were open-angle glaucoma. Before the repeated surgery ultrasound biomicroscopic (UBM) examination was performed on the primary filtering bleb, and the intraocular pressure (IOP) examination was followed after the repeated operation.


RESULTS
The mean follow-up period was (14.0 +/- 5.8) months (6 to 24 months). The examination of UBM showed that the filtering bleb disappeared and there was a liquid chamber under the superficial scleral flap in every failure case. The filtration failure due to the scarring at conjunctiva-Tenon's capsule-superficial scleral flap interface in 9 cases, proliferative membrane formation on the trabecular surface in 3 cases, micro-penetration of the trabecula in 1 case. At the end of follow-up, the IOP of 10 cases was lower than 21 mmHg without medication, the mean IOP level was (14.1 +/- 3.7) mm Hg, the IOP of 1 cases was 15 mmHg with Betagen, another 2 cases failed again 6 months after the repeated surgery and underwent the trabeculectomy at last. The complications included hyphema in one case and micro-penetration of the tabecula in one case.


CONCLUSIONS
The scarring at conjunctiva-Tenon's capsule-superficial scleral flap interface was the most important cause of NPTS with SKGeL implant failure. A repeated surgery with MMC through the initial surgical site may be a choice for the failure cases.