**6. Combined phacoemulsification–glaucoma drainage devices (GDDs)**

The first choice in the surgical management of glaucoma is a filtering operation. In some cases though, this type of surgical approach is thought to have low success rate. In these cases a GDD is the optimum choice.

**•** Primary surgery in open angle glaucoma (Ahmed GDD)

When deciding which GDD to use the surgeon should have in mind that:

occlusion of the lumen with 3/0 supramid suture (nylon braided)

produce significantly lower intraocular pressures [78-79]

complication rate (Tenon's cyst formation) [80-84].

**•** Valved GDDs allow unidirectional flow with low opening pressure and do not require

**Figure 6.** Decompression retinopathy. Insert: red free picture. This patient had a decrease of his visual acuity from 0.2 loMAR preoperatively to hand movements on the first postoperative day and the IOP dropped from 32 mmHg before surgery to 5 mmHg on the day after surgery. There was no leakage and the patient denied violent coughing or sneez‐ ing. The patient was prescribed the standard postoperative topical medication. An intravenous fluorescein angiogram did not show any evidence of central retinal vein occlusion. The visual acuity improved to preoperative level 3 months after surgery and the retinal haemorrhages gradually disappeared. IOP ranged from 7-14 mmHg without any topical

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 491

**•** Non valved GDDs require ligation of the lumen with 7/0 or 8/0 Vicryl suture and/or

**•** Size of plate: the larger the plate the larger the fibrous capsule around the plate and filtration area. However numerous studies have shown that in the long term the larger plates do not

**•** Plate material: silicone plates seem to do better than the polypropylene ones with lower

**6.2. Choice of GDD**

antiglaucoma drops (courtesy of Prof Kozobolis)

ligating suture

#### **6.1. Indications**

The indications for this combined procedure are the presence of visually significant cataract in the presence of the following conditions:


**Figure 6.** Decompression retinopathy. Insert: red free picture. This patient had a decrease of his visual acuity from 0.2 loMAR preoperatively to hand movements on the first postoperative day and the IOP dropped from 32 mmHg before surgery to 5 mmHg on the day after surgery. There was no leakage and the patient denied violent coughing or sneez‐ ing. The patient was prescribed the standard postoperative topical medication. An intravenous fluorescein angiogram did not show any evidence of central retinal vein occlusion. The visual acuity improved to preoperative level 3 months after surgery and the retinal haemorrhages gradually disappeared. IOP ranged from 7-14 mmHg without any topical antiglaucoma drops (courtesy of Prof Kozobolis)

**•** Primary surgery in open angle glaucoma (Ahmed GDD)

#### **6.2. Choice of GDD**

**Figure 5.** Hemorrhagic Descemet's membrane detachment 3 weeks postoperatively (arrow). The patient had a visual acuity of hand movements from 20/32 preoperatively. Six months after surgery the Descemet's membrane was com‐ pletely re-atteched with a small residual scar. IOP control was excellent throughout the postoperative period (courtesy

**6. Combined phacoemulsification–glaucoma drainage devices (GDDs)**

The first choice in the surgical management of glaucoma is a filtering operation. In some cases though, this type of surgical approach is thought to have low success rate. In these cases a GDD

The indications for this combined procedure are the presence of visually significant cataract

of Prof Kozobolis).

490 Glaucoma - Basic and Clinical Aspects

is the optimum choice.

**•** Failed trabeculectomy **•** Neovascular glaucoma

in the presence of the following conditions:

**•** Primary and secondary congenital glaucoma

**•** Extensive conjunctival scarring (e.g. buckle surgery)

**6.1. Indications**

**•** Corneal grafts

**•** Traumatic glaucoma

When deciding which GDD to use the surgeon should have in mind that:


#### **6.3. Antimetabolites and anti–VEGF**

There is conflicting evidence as to whether MMC and bevacizumab improve the success rate of Ahmed GDD. Mahdy et al [85] reported that both the application of MMC and injection of bevacizumab around the footplate of the GDD at the end of the operation improve the hypotensive effect. Alvarado et al [86] found that the use of high concentrations and applica‐ tion time of MMC also offer better hypotensive effect. On the other several other authors have reported that the intraoperative use of MMC did not improve the results of the GDD implan‐ tation [87-90].

**•** Tie the tube fixation suture. The suture must not occlude the lumen of the tube

**•** Suture Tenon's capsule and conjunctiva. The conjunctiva is first sutured at the limbus at its two corners. The relaxing incisions are sutured with running sutures. Finally the anterior edge of the conjunctiva is sutured to the limbus with two horizontal mattress sutures. We

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 493

**•** Supramid suture must protrude under the conjunctiva so that it can be removed later in the

The complications of the combined cataract-glaucoma surgery include those of phacoemulsi‐

Mechanism: formation of fibrous capsule around the plate. Management: antiglaucoma drops, ocular

● Tube/graft erosion through conjunctiva. Management: covering of the tube with donor sclera.

● Diplopia (large plate GDDs). Management: prisms, strabismus surgery, removal of GDD.

● Tube touching corneal endothelium. Management: repositioning of the tube

● Retraction of the GDD. Management: repositioning of the GDD

Causes: blood, fibrin, vitreous, iris. Management: removal of the agent that causes the obstruction with YAG

Topical antibiotic and steroids are given as for trabeculectomy. Antibiotics can be stopped one month postoperatively but steroids will need to be continued for longer. Cycloplegia is given for 2-3 weeks. Ahmed GDDs are renowned for their hypertensive phase which happens after

● incomplete obstruction of the non valved GDDs. Management: resuturing

● Leakage around the tube. Management: repositioning of the tube

**•** Tie patch graft sutures

postoperative period

fication and those of the GDDs.

● inflammation

● Hypotony(more likely with non valved GDDs)

● Hypertensive phase (most common with Ahmed GDDs).

massage, needling with 5-FU, removal of GDD

**6.5. Complications**

GDD complications

● Causes:

● Tube occlusion

laser or surgically.

● Endophthalmitis

● Endothelial decompensation

**6.6. Postoperative management**

use 10/0 nylon for this step of the procedure

#### **6.4. Surgical technique**

The surgical technique described below applies mainly to the Ahmed GDD as this is the GDD that we use.


**6.3. Antimetabolites and anti–VEGF**

tation [87-90].

that we use.

(optional)

incision)

facilitate the tube insertion

**6.4. Surgical technique**

492 Glaucoma - Basic and Clinical Aspects

There is conflicting evidence as to whether MMC and bevacizumab improve the success rate of Ahmed GDD. Mahdy et al [85] reported that both the application of MMC and injection of bevacizumab around the footplate of the GDD at the end of the operation improve the hypotensive effect. Alvarado et al [86] found that the use of high concentrations and applica‐ tion time of MMC also offer better hypotensive effect. On the other several other authors have reported that the intraoperative use of MMC did not improve the results of the GDD implan‐

The surgical technique described below applies mainly to the Ahmed GDD as this is the GDD

**•** 7/0 Vicryl corneal traction suture 4 mm from the limbus at the quadrant of the GDD insertion

**•** Conjunctival and Tenon's dissection (fornix based, supero-temporal quadrant preferably). Limbal peritomy extends for 3-4 o'clock hours. Relieving cuts are made perpendicular to

**•** When using large plate GDDs lateral/medial rectus muscles and superior rectus need to be

**•** Fixate plate on the sclera wit 8/0 nylon sutures. The plate is fixated 8mm from the limbus and the suture needles are passed through the holes at the anterior edge of the plate

**•** Prime valved GDDs. The GDDs are primed by irrigating BSS with a 30G blunt canula from

**•** Trim tube. The surgeon trims the tube with scissors allowing about 3 mm of the tube length

**•** Preplace patch graft sutures (8/0 nylon) on sclera. Two sutures are used one at each side of the graft. Preplacing the sutures reduces the period of hypotony during the GDD insertion.

**•** Do clear cornea phacoemulsification (away from the area of GDD insertion, suture main

**•** Create track for the tube with 22 or 23G needle. The needle is bent at 90° at two places with the bevel of the tip of the needle facing upwards. The needle is inserted 1 mm behind the limbus at a plane parallel to the iris. The needle is mounted on a viscoelastic syringe. Viscoelastic can be injected as the needle is withdrawn in order to keep the tract open and

**•** Insert tube in anterior chamber. The tube is grasped with serrated forceps near the tip and pushed along the needle track. It may need to be grasped several times until it is inserted

the limbus in order to achieve better exposure of the sclera.

the tip of the tube. BSS should exit at the proximal end of the tube

The patch graft may be sclera, pericardium, cornea, fascia lata or dura.

to enter in the anterior chamber in front of the iris

**•** Preplace tube fixation suture (9/0 silk) on sclera

isolated with brindle 4/0 silk sutures


#### **6.5. Complications**

The complications of the combined cataract-glaucoma surgery include those of phacoemulsi‐ fication and those of the GDDs.

#### GDD complications

	- Causes:
		- incomplete obstruction of the non valved GDDs. Management: resuturing
		- Leakage around the tube. Management: repositioning of the tube
		- inflammation

Mechanism: formation of fibrous capsule around the plate. Management: antiglaucoma drops, ocular massage, needling with 5-FU, removal of GDD

● Tube occlusion

Causes: blood, fibrin, vitreous, iris. Management: removal of the agent that causes the obstruction with YAG laser or surgically.


#### **6.6. Postoperative management**

Topical antibiotic and steroids are given as for trabeculectomy. Antibiotics can be stopped one month postoperatively but steroids will need to be continued for longer. Cycloplegia is given for 2-3 weeks. Ahmed GDDs are renowned for their hypertensive phase which happens after 3-6 weeks as fibrous tissue is forming around the plate. The IOP must be lowered with topical antiglaucoma medication or even acetozolamide tablets. Needling of the fibrous capsule with 30G needle may be tried with injection of dexamethasone and 5FU as for trabeculectomy.

#### **6.7. Outcomes**

The combined surgery does not seem to adversely affect the hypotensive effect of the GDD [91].
