New minimally invasive, deep sclerotomy ab interno surgical procedure for glaucoma, six years of follow-up.

Purpose: The goal of this study is to show the efficacy and safety of an innovative surgical procedure regarding the treatment of open-angle and juvenile glaucoma known as sclerothalamotomy ab interno (STT ab interno).

Patients And Methods: Between February and July 2002 surgery was performed in 58 eyes of 58 consecutive patients, of which 53 were diagnosed with open-angle and 5 with juvenile glaucoma. The procedure was performed with the assistance of a custom-made high-frequency dissection probe (19 gauge with a tip of 0.3 × 1 mm), which applies a bipolar current of 500 kHz frequency. The probe penetrates approximately 1 mm into the nasal sclera (ab interno) and through the trabecular meshwork and Schlemm's canal, thus forming a deep sclerotomy or "thalami" of 0.3 mm height and 0.6 mm width.

Results: The average baseline intraocular pressure (IOP) was 25.6 ± 2.3 mm Hg (range: 18-48 mm Hg) for the open-angle glaucoma group and 39.6 ± 2.3 mm Hg (range: 34-46 mm Hg) for the juvenile glaucoma group. All patients had a minimum follow-up of 72 months. The mean IOP for the stated period was 14.7 ± 1.8 mm Hg for the open-angle glaucoma group and 13.2 ± 1.3 mm Hg for the juvenile group. The IOP after surgery was statistically significantly lower than the baseline IOP at all measured intervals (P < 0.001). After 72 months only 11 eyes accounted for a 20.8% continuous antiglaucoma therapy. With regard to the procedure no serious complication was documented.

Conclusions: Sclerothalamotomy ab interno is a minimally invasive, safe, and efficient surgical technique for lowering the IOP in open-angle and juvenile glaucoma.