Ординатура / Офтальмология / Английские материалы / Step by Step Minimally Invasive Glaucoma Surgery_Garg, Melamed, Bovet, Pajic, Carassa, Dada_2006

232 Step by Step Minimally Invasive Glaucoma Surgery

great demand on surgical skill, which can be mitigated to some extant only by expensive diamond blades! The data on long-term results is often conflicting, at best equivocal.

Given these constraints, why would one want to take up this procedure, that to with modifications?

DEEP SCLERECTOMY WITH T-FLUX IMPLANT WITH SUPRA-CHOROIDAL DRAINAGE

The plain and simple answer is that DS with T-flux with supra-choroidal drainage is the surgery of the future. With the introduction of the T-flux implant one merely enhances the outcomes of a well done deep sclerectomy; however, with the added dimension of supra-choroidal drainage one virtually ensures perpetual outflow.

The key step in this procedure is to make an aperture in the sclera, (Figs 13.6A to C) 2-3 mm from the limbus, up to the supra-choroid and insert the foot of the T-flux into this potential space. Being about 0.2 mm thick, it glides in easily (Figs 13.7A and B).

Fig. 13.6A: Deep sclerectomy

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Figs 13.6B and C: Supra-choroidal entry

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Figs 13.7A and B: Inserting foot of T-flux in supra-choroidal

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In one procedure it combines:

a.Safety — One does not need to open the anterior chamber.

b.Efficacy — Performed painstakingly, the procedure offers adequate drainage.

c.Sheltered drainage — One can largely circumvent the deleterious effects of naked outflow by placing the T- flux upside down, thus providing a roof over outflow. There is also little chance of prolonged sclero-aqueous contact to induce any degree of significant fibrosis.

d.Continuous drainage — By inserting the foot of the T- flux into the supra-choroid, one creates a channel along which fluid passively tracks down. Nature does the rest (Fig. 13.8). This is perhaps the only surgery that can ensure perpetual drainage, by utilizing the inherent vascularity of the choroid and its ability to absorb and return fluid to the general circulation. There is thus, no fear of closure of the ‘external lake’ as with the AGV and Molteno designs.

Fig. 13.8: T-flux with supra-choroidal lake

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During the period 2001-2002, I had an occasion to perform this procedure on five eyes in three patients. All patients also had significant cataract, necessitating combined surgery. All patients followed up regularly as advised, on weekly, monthly, quarterly and annual basis for three and a half years. Patient 1 (2 eyes) passed away 42 months after surgery, while patients 2 and 3 continue their annual follow-up.

The mean preoperative IOP fell from a value of 28 to 13 mm at 1 month, stabilizing at 15 mm at end of 1 year, 17 mm at end of 2 years, and 18 mm at end of 3 years, 6 months (Fig. 13.9). During his period field remained stable without any topical therapy (Fig. 13.10).

Fig. 13.9: Postoperative IOP

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Figs 13.11A and B: UBM at 1 year

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d.Inserting the foot of the implant in to the suprachoroidal space.

1.I generally prefer a peri-bulbar block.

2.A superior rectus bridle suture follows.

3.A standard fornix-based conjunctival flap is then dissected.

4.The scleral flap has to be a minimum of 5 × 5 mm (Figs 13.12A and B) with 1/3rd depth.

5.Within this flap, another 4 × 4 mm scleral pocket is dissected (Fig. 13.13).

6.Deep sclerectomy is then performed (Figs 13.14A and B).

7.Next, side pockets are made above the level of the deep sclerectomy in order to accommodate and embed the arms of the T-flux implant (Figs 13.15A and B).

Fig. 13.12A: Caliper

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Fig. 13.12B: Flap dissection

Fig. 13.13: Scleral pocket

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Figs 13.14A and B: Deep sclerectomy