Tunnel Trabeculectomy: A Modified Procedure with Long – Term Follow up

1. Tunnel Trabeculectomy:A Modified Procedure withLong – Term Follow up By Ahmad M. Abdallah, MD Ass. Prof. of Ophthalmology

2. INTRODUCTION

3. Trabeculectomy is still the most popular filtering surgery that provides adequate IOP control in many glaucoma patients. However, the main disadvantage of this procedure in the early postoperative period is excessive aqueous filtration that can result in many complications: * Hypotony * Choroidal detachment * Shallow AC * Iridocorneal touch * PAS * Failure of surgery.

4. ▪ Attempts to reduce early postoperative excessive filtration included: (1) Tight suturing of the scleral flap followed by laser suture lysis later on. Disadvantages are: ۰High IOP & poor aqueous drainage till sutures are cut ۰Conjunctival hole with aqueous leak and infection ۰Unsuccessful due to thick conjunctiva over sutures. (2) Tight releasable sutures which are released after few days. Disadvantages are: ۰High IOP & poor aqueous drainage till sutures are released ۰Aqueous leak and infection through the suture track.

5. Aim of the Work

6. To describe a new surgical modification of the conventional trabeculectomy procedure and to evaluate its efficacy in controlling the IOP and in reducing the rate of complications related to excessive aqueous filtration in adult patients with primary glaucoma.

7. Patients & Methods

8. ● A prospective study on eyes with medically uncontrolled primary glaucoma. ● Full ophthalmic examination, including: Best – corrected visual acuity measurment Applanation tonometry Gonioscopy Field of vision Fundus examination ● Exclusion criteria included: Patients with secondary glaucomas. Patients with recurrent glaucoma. Congenital glaucoma. Patients with previous intraocular surgery Patients with advanced lens opacities.

9. Patients were randomized into 2 matched groups according to the surgical technique used: Tunnel Trabeculectomy ( TT ) Group: included 46 eyes with primary glaucoma (34 open angle & 12 closed angle) that were subjected to tunnel trabeculectomy. Conventional Trabeculectomy ( CT ) Group: included 45 eyes with primary glaucoma (32 open angle & 13 closed angle) that were subjected to conventional trabeculectomy, and was considered as a control group.

10. Postoperatively: Patients were examined at the 1st. postoperative day, then weekly for 1 month, monthly till the 6th. month and then every 6 months till the end of the follow up period. The main outcome parameters are: ۰ IOP ۰ Visual acuity ۰ No. of antiglaucoma medications needed to control IOP ۰ Bleb shape & extension ۰ Reported complications.

11. Fig. 1: Dissection of the scleral flap.

12. Fig. 2: Dissection of the scleral tunnel.

13. Fig. 3: The tunnel after cutting the 2nd flap and trabecular meshwork.

14. Fig. 4: Tight closure of the 1st scleral flap.

15. RESULTS

16. ☻The TT Group: ♦46 eyes; 29 were males and 17 were females. ♦ Age ranged from 44 to 68 years (56.4 ± 6.7 years). ♦ Follow up duration ranged from 17 to 33 months (25.7 ±8.3 months).

17. ☻The TT Group: ♦45 eyes; 26 were males and 19 were females. ♦ Age ranged from 42 to 69 years (55.1 ± 7.4 years). ♦ Follow up duration ranged from 19 to 35 months (26.6 ±7.6 months).

18. The mean Postoperative IOP in the 2 groups • The mean IOP at the 1st postop. Day was higher in TT group than CT group (8.3 ± 2.6 mmHg vs 5.8 ± 2.1 mmHg). The difference was statistically significant. • At the end of F/U period the mean IOP was reduced by 43.8% (15.3 vs 27.2 mmHg) for TT group, while it was reduced by 38.7% (16.5 vs 26.9 mmHg) for CT group, indicating better long-term reduction of the mean IOP (although the difference was statistically insignificant) (Table 1)

19. Table 1:The mean IOP at different durations in both groups.

20. At the end of the follow up, the surgical outcome in both groups is shown in (Table 2).

21. Table 2: The surgical outcome in both groups.

22. The different types of the filtering blebs in both groups, at the end of the follow up period, are shown in (Table 3).

23. Table 3: Types of the filtering bleb in both groups.

24. Table 4: The complications reported in both TT and CT groups.

25. Discussion

26. Modificationsin the already present glaucoma surgeries as well as development of new surgical techniques will persist until there is a glaucoma surgery which is 100% successful for surgical treatment of glaucoma patients. Tunnel trabeculectomy (TT) differs from the conventional trabeculectomy (CT) in 2 aspects: (1) The tunnel created in the scleral bed under the scleral flap and extends from 1 – 2 mm before the posterior edge of the flap to the trabeculectomy site. (2) Tight suturing of the scleral flap.

27. Advantages of the Tunnel Trabeculectomy: ♣Tight suturing of the flap minimizes the postoperative hypotony and the complications related to excessive filtration. ♣The tunnel maintains a continuous aqueous outflow adequate to control the IOP. ♣ The relatively posterior location of the bleb is cosmetically better, reduces irritation caused by the bleb and prevents extension of the bleb onto the cornea. ♣ Higher incidence of diffuse bleb. ♣ Avoids the aqueous leak and infection that may complicate laser suture lysis or removal of releasable sutures.

28. Conclusion

29. The Tunnel modification of the conventional trabeculectomy increases its long – term success in IOP control and significantly reduces the rate of complications related to excessive filtration as well as the need for postoperative antiglaucoma medications, in adult patients with primary glaucoma.

30. Thank You