**5. Combined phacoemulsification–non penetrating glaucoma surgery (NPGS)[deep sclerectomy (DS)–Viscocanalostomy (VC)]**

#### **5.1. Aqueous humor dynamics in NPGS**

The search for a filtering surgery that would minimize the complications of the penetrating surgery has led to the development of the non penetrating procedures in which the anterior chamber is not entered. The aqueous from the anterior chamber percolates through the trabeculo-Descemet's membrane (TDM) either in the episcleral space and then in the subcon‐ junctival/sub-Tenon's space (fig 2), or in the Schlemm's canal (SC) and suprachoroidal space. As the aqueous diffuses to routes other that the subconjunctival/sub-Tenon's space these procedures do not always show elevated filtering blebs. This is especially true for viscocana‐ lostomy in which the aqueous is directed in the enlarged SC and the tight suturing of the scleral flap is considered as a crucial part of the surgical procedure.

**Figure 2.** Aqueous in the subconjunctival space flowing DS. A: bleb wall, B: bleb cavity (courtesy of Prof Kozobolis).

#### **5.2. Indications**

● Bleb leak. Management: pressure patch, large diameter contact lens, cyanoacrylate glue, autologous blood,

● Cyclodialysis cleft. Management: mydriatics, laser photocoagulation/cryotherapy/suturing of the cleft with 7/0 or 8/0 nylon sutures as the 10/0 nylon may not be strong enough the hold the cleft closed if the IOP increases

In the presence of a very shallow anterior chamber management should include reformation of the anterior chamber with viscoelastic and if there are large choroidal effusions which touch each other (kissing choroidals) then they must be drained via sclerostomies. If the choroidal effusions are not touching each other they can be conservatively

Causes: scarring. Management: bleb needling, injection of 5-FU/MMC, trabeculectomy revision/redo, glaucoma

Cause: thin walled bleb. Risk factors: antimetabolites. Management: aqueous suppressants, large diameter bandage contact lens, autologous serum, cyanoacrylic glue, autologous blood injection in the bleb, conjunctival

Risk factors: thin walled blebs, bleb leaks, exposed sutures, antimetabolites, blepharitis, conjunctivitis,

**5. Combined phacoemulsification–non penetrating glaucoma surgery**

The search for a filtering surgery that would minimize the complications of the penetrating surgery has led to the development of the non penetrating procedures in which the anterior chamber is not entered. The aqueous from the anterior chamber percolates through the trabeculo-Descemet's membrane (TDM) either in the episcleral space and then in the subcon‐ junctival/sub-Tenon's space (fig 2), or in the Schlemm's canal (SC) and suprachoroidal space. As the aqueous diffuses to routes other that the subconjunctival/sub-Tenon's space these procedures do not always show elevated filtering blebs. This is especially true for viscocana‐

● Persistent hypotony due to MMC effect (toxic effect on the ciliary body) [59,60]

**(NPGS)[deep sclerectomy (DS)–Viscocanalostomy (VC)]**

Management: sample cultures, broad-spectrum antibiotics (for blebitis), vitreous tap, intravitreal antibiotics ±

managed with cycloplegics, topical steroids. Periocular and oral steroids can also be given

suturing of the conjunctiva

484 Glaucoma - Basic and Clinical Aspects

*Late postoperative*

● Late bleb failure

drainage implants ● Late bleb leak

● Aqueous shutdown. Management: topical steroids

dramatically in the early postoperative period.

excision with conjunctival advancement or flap ● Blebitis and bleb related endophthalmitis

nasolacrimal duct obstruction, diabetes.

vitrectomy (for bleb related endophthalmitis)

**5.1. Aqueous humor dynamics in NPGS**

Causes: infection of the bleb by various micro-organisms.

The main indication for combined phaco-NPGS is the primary open and secondary open angle glaucomas in the presence of visually debilitating cataract.

### **5.3. Contraindications**

Non penetrating glaucoma surgery is useful in open angle glaucomas but should be avoided in closed angle glaucomas as the peripheral iris in these cases blocks the TDM and obstructs the percolation of aqueous. NPGS has also been used in congenital and juvenile glaucomas [61-63].

#### **5.4. Antimetabolites**

The adjunctive use of MMC in NPGS showed better hypotensive effect at the cost of higher rate of complications (thin avascular blebs, transconjunctival oozing) [64,65].

#### **5.5. Pre–operative preparation**

The same principles apply for the pre-operative preparation as for trabeculectomy

#### **5.6. Surgical technique**

The following steps are the technique of choice of the authors for the combined phacoemulsi‐ fication-DS procedure:


**•** 10/0 nylon suture at the site of the main incision of the phacoemulsification

**•** Tight suturing of the superficial flap to sclera with two 10/0 Nylon sutures

**•** Peeling of the inner wall of SC and juxtacanalicular trabeculum

site and two-site phaco-VC showed the same level of success [67].

**•** Cannulation of the SC with the injection of high molecular weight viscoelastic device

**•** Unroofing of SC and dissection of deep peripheral corneal stroma from underlying Desce‐

**Figure 3.** Deep sclerectomy site after excision of the deep scleral flap and peeling of the inner wall of the SC (courtesy

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 487

Viscocanalostomy with or without the use of an implant has the same success rate [66]. One-

Topical steroids and antibiotics are given as in trabeculectomy. Again as for trabeculectomy antibiotics can be stopped after 4 weeks but steroids can be continued for 6 months or even longer at a low frequency. Cycloplegia is not necessary. As DS (and VC to a lesser extent) relies on a bleb formation for IOP control needling may be required if there is subconjunctival scarring or Tenon's cyst formation which are managed as described above. Tight sclera flap

**•** Deep scleral flap formation as for DS

**•** Excision of the deep scleral flap

**5.7. Postoperative management**

**•** Conjunctival closure with 10/0 nylon sutures.

met's membrane

of Prof Kozobolis)


For viscocanalostomy (VC) the steps are:


**Figure 3.** Deep sclerectomy site after excision of the deep scleral flap and peeling of the inner wall of the SC (courtesy of Prof Kozobolis)


**•** Application of MMC (0.2 mg/ml for 2-3 minutes) with the use of a few pieces of a lasik shield under the conjunctiva. The edges of the conjunctiva are lifted and wiped off the MMC

**•** Formation of a superficial scleral flap at 1/3 of sclera thickness. After the sclera incisions the sclera is dissected anteriorly with a diamond knife until it projects for 1.5 mm into clear

**•** 2.75 mm clear cornea phacoemulsification from a temporal approach with injectable

**•** The superficial flap is then everted over the cornea and a second deeper triangular scleral flap is dissected under high magnification leaving a very thin layer of scleral tissue over the

**•** This second flap is dissected anteriorly in order to deroof Schlemm' s canal followed by the removal of the inner wall of SC and the juxtacanalicular trabeculum with the purpose of

**•** The superficial scleral flap is repositioned and secured with two 10/0 nylon sutures in a tent

**•** Viscoelastic (sodium hyaluronate 1%) is then injected under the scleral flap in order to create

**•** Conjunctival and Tenon's layer closure in one plane with 10/0 nylon sutures in the same

**•** Triamcinolone or celectone chronodose injection subconjunctivally 0.1 ml behind the scleral flap at the end of the operation. 0.1 ml of garamycin (80 mg in 2 ml solution) are injected

**•** Application of MMC (0.2 mg/ml for 2-3 minutes) with the use of a few pieces of of a lasik

**•** Clear cornea phacoemulsification from a temporal approach with injectable intraocular lens

**•** The area of MMC application is then irrigated with 20 ml of balanced salt solution

**•** 10/0 nylon suture at the site of the main incision of the phacoemulsification

solution

486 Glaucoma - Basic and Clinical Aspects

cornea

uvea.

**•** Bipolar cautery is kept to a minimum

increasing the aqueous outflow (fig 3)

a space for the pooling of the aqueous humor

**•** Viscoelastic is then injected under the conjunctiva

shield arranged over a wide area under the conjunctiva.

**•** Excision of the deep scleral flap

fashion as for trabeculectomy.

subconjunctivally in the lower fornix

For viscocanalostomy (VC) the steps are:

**•** Superficial scleral flap creation as for DS

**•** Conjunctival dissection as for DS

insertion

– like formation

intraocular lens insertion


Viscocanalostomy with or without the use of an implant has the same success rate [66]. Onesite and two-site phaco-VC showed the same level of success [67].

#### **5.7. Postoperative management**

Topical steroids and antibiotics are given as in trabeculectomy. Again as for trabeculectomy antibiotics can be stopped after 4 weeks but steroids can be continued for 6 months or even longer at a low frequency. Cycloplegia is not necessary. As DS (and VC to a lesser extent) relies on a bleb formation for IOP control needling may be required if there is subconjunctival scarring or Tenon's cyst formation which are managed as described above. Tight sclera flap sutures are treated with argon laser suturolysis. Specifically for NPGS YAG laser puncture can be performed in case of iris prolapsed through the TDM with high IOP. The settings used are single pulsed shots, 3-5 mJoules through a gonioscopy lens. Pilocarpine 2% and argon laser iridoplasty can be used to pull away the iris from the site of incarceration. The settings for iridoplasty are 300-400µ spot size, 0.2 seconds exposure time, 300-400mWatt power through an iridectomy lens. If the IOP in the early or late postoperative period is thought to be due to poor aqueous filtration through the TDM, then YAG laser goniopuncture of the TDM can be tried. The settings are single pulsed shots, 4-6mJoules energy through a gonioscopy lens.

● Ciliary body shutdown due to inflammation. Management: steroids

● Poor filtration through TDM. Management: YAG laser microperforations to TDM

● Bleb encapsulation. Management: bleb needling with 5-FU/MMC injections

● Ocular decompression retinopathy [75] (fig 6 ). It is caused by a sudden drop of the IOP during surgery. It is not exclusively seen in NPGS but also in penetrating glaucoma surgery, YAG laser iridotomy, and medical

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 489

● Conjunctival scarring. Management: intensive topical steroids, subconjunctival injection of 5-FU/MMC

**Figure 4.** Hemorrhagic Descemet's membrane detachment (arrow) as seen through a Goldmann 4-mirror lens (cour‐

● Hemorrhagic Descemet's membrane detachment [74] (fig 4,5)

● MMC effect (toxic effect on the ciliary body)

●rupture of the TDM with iris prolapsed

● Ciliary body shutdown due to inflammation

● Late hypertony ● Causes:

● Late hypotony ● Causes

● MMC effect

tesy of Prof Kozobolis)

● Conjunctival wound leak

● Blebitis and bleb related endophthalmitis

treatment for acute primary closure glaucoma (76,77)

#### **5.8. Outcomes**

As opposed to phacotrabeculectomy, combined phaco-DS has better outcomes in terms of IOP control than DS alone [68]. Phacotrabeculectomy and phaco-DS showed no statistical differ‐ ence in the IOP control although the phacotrabeculectomy groups tend to have lower IOP. Phaco-DS was the safer procedure in terms of complication rates [69,70].

Similarly viscocanalostomy offers slightly better hypotensive effect than phacoviscocanalos‐ tomy [71]. Compared to phacotrabeculectomy, phaco-VC offers similar IOP control in patients with primary open angle glaucoma. [72,73]

#### **5.9. Complications**

The complications of the combined cataract-glaucoma surgery include those of phacoemulsi‐ fication and those of NPGS. The latter can be divided into intraoperative and postoperative.

#### ● Intraoperative

	- Early hypertony.
		- Causes:
			- retained viscoelastic. Management: observation, antiglaucoma drops, aspiration
			- haemorrhage in the scleral bed. Management: none required
			- Steroid response. Management: antiglaucoma drops, non-steroidal anti-inflammatory drugs
			- Rupture of the TDM with iris prolapse. Mechanism: rubbing of the eye, Valsalva's maneuver. Management: miotics, steroids, YAG laser of the prolapsed iris, argon laser iridoplasty, surgical removal of iris tissue
			- Pupillary block, aqueous misdirection, suprachoroidal haemorrhage. Management: as in trabeculectomy
	- Early hypotony
		- Causes:
			- Conjunctival wound leak. Management: suturing

● Ocular decompression retinopathy [75] (fig 6 ). It is caused by a sudden drop of the IOP during surgery. It is not exclusively seen in NPGS but also in penetrating glaucoma surgery, YAG laser iridotomy, and medical treatment for acute primary closure glaucoma (76,77)

	- Causes:

sutures are treated with argon laser suturolysis. Specifically for NPGS YAG laser puncture can be performed in case of iris prolapsed through the TDM with high IOP. The settings used are single pulsed shots, 3-5 mJoules through a gonioscopy lens. Pilocarpine 2% and argon laser iridoplasty can be used to pull away the iris from the site of incarceration. The settings for iridoplasty are 300-400µ spot size, 0.2 seconds exposure time, 300-400mWatt power through an iridectomy lens. If the IOP in the early or late postoperative period is thought to be due to poor aqueous filtration through the TDM, then YAG laser goniopuncture of the TDM can be tried. The settings are single pulsed shots, 4-6mJoules energy through a gonioscopy lens.

As opposed to phacotrabeculectomy, combined phaco-DS has better outcomes in terms of IOP control than DS alone [68]. Phacotrabeculectomy and phaco-DS showed no statistical differ‐ ence in the IOP control although the phacotrabeculectomy groups tend to have lower IOP.

Similarly viscocanalostomy offers slightly better hypotensive effect than phacoviscocanalos‐ tomy [71]. Compared to phacotrabeculectomy, phaco-VC offers similar IOP control in patients

The complications of the combined cataract-glaucoma surgery include those of phacoemulsi‐ fication and those of NPGS. The latter can be divided into intraoperative and postoperative.

● Perforations of the TDM. Management: if small no further management is required. If they are large with iris

● retained viscoelastic. Management: observation, antiglaucoma drops, aspiration

● Steroid response. Management: antiglaucoma drops, non-steroidal anti-inflammatory drugs

● Rupture of the TDM with iris prolapse. Mechanism: rubbing of the eye, Valsalva's maneuver. Management: miotics, steroids, YAG laser of the prolapsed iris, argon laser iridoplasty, surgical removal of iris tissue ● Pupillary block, aqueous misdirection, suprachoroidal haemorrhage. Management: as in trabeculectomy

● haemorrhage in the scleral bed. Management: none required

● Conjunctival wound leak. Management: suturing

Phaco-DS was the safer procedure in terms of complication rates [69,70].

with primary open angle glaucoma. [72,73]

prolapse a peripheral iridectomy should be carried out.

**5.8. Outcomes**

488 Glaucoma - Basic and Clinical Aspects

**5.9. Complications**

● Intraoperative

● Hyphaema ● Postoperative

> ● Early hypertony. ● Causes:

● Early hypotony ● Causes:

	- Causes
		- Conjunctival wound leak
		- Ciliary body shutdown due to inflammation
		- MMC effect

**Figure 4.** Hemorrhagic Descemet's membrane detachment (arrow) as seen through a Goldmann 4-mirror lens (cour‐ tesy of Prof Kozobolis)

**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 of Prof Kozobolis).
