Study On The Effect Of Modified Stegmann Surgery On Open-angle Glaucoma

Objective: To evaluate the efficacy, feasibility and security of modified Stegmannsurgery on open-angle glaucoma experimentally and clinically.Methods: In experimental study, Ocular hypertension model was induced byintra-ocular injection of a -chymotrypsin in the posterior chamber in Janpanese white rabbits. One eye of every rabbit was randomly assigned to undergo the modified Stegmann surgery, the other was to receive traditional trabeculectomy. At the different time-points post-operatively, clinical manifestation , intraocular pressure (IOP) and filtering blebs were recorded, with the filtering areas examined by ultrasound biomicroscopy (UBM);And the aqueous humor was collected and tested by ELISA for the level of TGF- β₂, and the expression of bFGF in the tissue of surgical field was measured by using immunohistochemistry. On the other hand, in a clinal pilot study, 27 eyes of 17 cases with medically uncontrolled primary open-angle glaucoma underwent modified Stegmann surgery. Clinical manifestation , IOP, visual acuity and drugs used for anti-glaucoma, post-operatively, were also analyzed. And all patients were undertook ultrasound biomicroscopy (UBM) to evaluate the surgical site.Results: In experimental study, (1) The animal model of ocular hypertension couldbe successfully induced by intra-ocular injection of a -chymotrypsin in the posterior chamber at the concentration of 320U/0.25ml in Janpanese white rabbits, and its incidence rate was surprisingly 100%, with stable and high intraocular pressure and little badly-effect. (2) The intraocular pressure in the eyes underwent by modified Stegmann surgery, were decreased postoperatively, while its extent was reduced withthe follow-up time. Compared to the intraocular pressure preoperatively, there was significantly difference at the days 7 and days 14 postoperatively in modified Stegmann surgery, respectively, while there was no significantly difference at the days 21 and days 28 postoperatively. And there was significantly difference in the IOP at the days 3 and days 7 postoperatively between modified Stegmann surgery and trabeculectomy, while there was no significantly difference at other time. (3) The levels of TGF- P 2 in aqueous humor and bFGF in surgical field were both rapidly increased after the two surgeries, with its peak-time at the days 7 postoperatively, then decreased at the days 14, the former reached the baseline level at the days 21 and days 28 postoperatively, while the latter was still superior to the baseline preoperatively. And there was significantly difference in the level of bFGF at the days 7 postoperatively and TGF- 3 2 at the days 14 between modified Stegmann surgery and trabeculectomy, while there was no significantly difference at other time. In the clinical pilot study, (1) the mean IOP preoperatively was (30.91 + 14.06) mmHg, decreased to (7.09 + 4.78) mmHg at the first day after the modified Stegmann surgery> (8.38 + 3.81) mmHg at the days 7^ (14.84+6.51) mmHg at the month K (13.38±3.40) mmHg at the month 6 and (16.08+3.24) mmHg at the month 12, respectively. There was significantly difference in the IOP between at every time-point postoperatively and preoperatively. (2) The number of drugs used for anti-glaucoma was (2.00+0.62) preoperatively, and (0.26+0.66) at the months 6 postoperatively and (0.52+0.67) at the months 12, the difference being significant, respectively. At the months 12, the successs rate, defined as an IOP below 21 mmHg with and without medication, was 95.7% (22/23), and the complete successs rate, defined as an IOP below 21 mmHg without medication, was 56.5% (13/23). (3) The visual acuity remained stable postoperatively, with mild inflammation in the anteriorchamber and few complications after the operation. (4) Strong echoes of polyglactin suture was shown by UBM at the postoperative days 7 and month 1, and disappeared completely at the months 3, while low echoes of liquid space existed under the scleral flap was still shown at the months 12 postoperatively.Conclusions: Modified Stegmann surgery could effectively lower the IOP andreduce the sorts of antiglaucomalous medications, with the unchanged visual acuity. The postoperative complications were much fewer because of no penetration of the anterior chamber. And the polyglactin sutures were cheap and easy to obtain. Therefore, it is a very hopeful and practicable new anti-glaucomalous surgery.