NONPENETRATING DEEP SCLERECTOMY (NPDS) WITH OR WITHOUT COLLAGEN DEVICE (CD) IN PRIMARY OPEN-ANGLE GLAUCOMA - MIDDLE-TERM RETROSPECTIVE STUDY

The purpose of this study is to evaluate the middle-term tonometric re sults of a new filtering procedure, the nonpenetrating deep sclerectom y with or without collagen device, in primary open-angle glaucoma. Thi s technic aims to eliminate or minimize the complications of classical trabeculectomy. Method: This procedure was carried out by Koslov and colleagues. This is performed under a limbal-based conjunctival flap a nd a superfical scleral flap, the ablation of a deep scleral flap taki ng away the external wall of Schlemm's canal, only living in place the Descemet membrane. One must obtain a visible filtration across the op ened Schlemm's canal and Descemet membrane. To improve the aqueous fil tration, a cylindric collagen device, made from porcine scleral tissue , biocompatible, known for its high water content, is fixed in the dee p scleral bed with a 10/0 nylon suture. This device provides a support for the elimination route of aqueous humor and acts like a sponge, ca rrying the liquid by capillary action. It is sterilized by irradiation . Full guarantee against viral contamination is provided. This procedu re ends in one suture (10/0 nylon) of superficial scleral flap and con junctival closing suture. When NPDS is performed without CD, a sponge of 5FU is used and the superficial scleral flap is not sutured. Retros pective study: Our material included 111 patients, 148 eyes in CD grou p; 43 patients, 55 eyes in the group without CD. The average follow-up was 13.3 +/- 5.8 months in the CD group, 7.2 +/- 3.5 months in the gr oup without CD. All patients presented a POAG without risk factors of bleb failure. Results: The a average IOP before the operation and at t he end of the follow-up period was 7.2 +/- 6.3 mmHg in the CD group; 8 .3 +/- 7.6 mmHg in the group without CD (no significant difference). T he probability-success rate with the Kaplan-Meier method (IOP less tha n or equal to 20 mmHg) was, in the CD group, at 18 months, 68% and 69% in the group without CD, without medical treatment. With monotherapy, the success rate was 85% in the CD group, 74% in the group without CD (p less than or equal to 0.05). Prospective study: Afterwards, we hav e conducted a prospective study comparing two groups of patients with POAG without risk factors of bleb failure, operated with and without c ollagen device, without 5FU in the second group. Our material included 31 patients, 31 eyes, one eye for each patient, two surgeons; 17 eyes in the CD group, 14 eyes in the group without CD. The average age was 65.8 +/- 8.2 years in the first group; 64.1 +/- 10.3 in the second gr oup. The average follow-up was 11 months in both groups. Results: Delt a average IOP was 8.3 +/- 5.8 in the CD group; 12.3 +/- 6 in the group without CD (p < 0.05). The probability-success rate without treatment at 12 months: 58% in the first group, 90% in the second group (p < 0. 05) and with monotherapy: 80% and 90% (N.S.). In both studies, in both groups, except microperforations, more frequent in the prospective gr oup without CD, no complications of the trabeculectomy were observed. The mean change in visual acuity was inferior to 0.1 at the end of the follow-up. A postoperative rise in IOP can occur. It can be due to an internal obstruction (goniosynechiae or bad filtration). It can be tr eated with Nd-Yag laser. It can also be due to external obstruction, t reated by 5FU injections into the bleb. The success of these procedure s were similar in the whole group. Conclusion: Non penetrating deep sc lerectomy can be considered as an excellent alternative to trabeculect omy in open and wide angles. It does not modify visual acuity. It carr ies away less complications than trabeculectomy and the use of antimit otic agents is safer. Collagen device does not seem, at middle-term, t o improve tonometric results.