Trabeculectomy, phaco and IOL implantation

Combined trabeculectomy and phacoemulsification lead to low astigmatism and early stabilization of refraction.

ByAmar Agarwal, MS, FRCS, FRCOphth

ByAthiya Agarwal, MS, FRCS, FRCOphth

BySunita Agarwal, MS, FRCS, FRCOphth

Trabeculectomy has been done as a surgical option to control IOP in patients with uncontrolled primary open-angle glaucoma. In many elderly patients, treatment of coexisting cataract during a trabeculectomy assumes importance. Reports indicate that combined trabeculectomy and cataract surgery is effective in treating such cases.

We discuss the technique of combined trabeculectomy and phacoemulsification with an IOL implantation for patients with primary open-angle glaucoma (POAG) and coexistent visually significant cataract.

The patients are tried on maximum medications, and trabeculectomy is offered as an option only when the IOP does not get controlled with maximum medications. Trabeculectomy combined with phacoemulsification and IOL implantation is advised if an associated cataract was visually significant.

Two-step surgical technique

All patients are operated under peribulbar anesthesia. A two-site procedure is performed rather than a single-site technique.

Preparation of the scleral flap

Trabeculectomy was always done at the 12-o’clock position. First of all, a superior rectus bridle suture is fixed so that good exposure is present superiorly. A fornix-based superior conjunctival flap is then created. Wet field bipolar cautery is applied when necessary. A quadrilateral partial thickness 5-mm by 4-mm scleral flap is then taken. The flap is dissected anteriorly up to the sclerocorneal junction using the same scleral tunnel knife that one would use to create a scleral tunnel for phaco. Once the flap has been created, it is lifted up with a forceps to see that it is complete.

Phaco

The anterior chamber is then entered with a 26-ga needle, and viscoelastic substance is injected. This incision is made temporally. The needle with viscoelastic is injected inside the eye in the area where the second site is made. This will distend the eye so that when you make a clear-corneal incision, the eye will be tense and one can create a good valve. Now, use a straight rod to stabilize the eye with the left hand. With the right hand, make the clear-corneal incision. A temporal 2.8-mm clear-corneal incision is made with a diamond knife.

When we started making the temporal incisions, we positioned ourselves temporally. The problem with this method is that every time the microscope has to be turned, it affects the cables connected to the video camera. Further, the theater staff would get disturbed between the right eye and the left eye. To solve this problem, we then decided on a different strategy. We have operating trolleys on wheels. The patient is wheeled inside the operation theater, and for the right eye, the trolley is placed slightly obliquely so that the surgeon does not change his or her position. The surgeon stays at the 12-o’clock position. For the left eye, the trolley with the patient is rotated horizontally so that the temporal portion of the left eye comes at 12 o’clock. This way, the patient is moved and not the surgeon.

Capsulorrhexis with a bent 26-ga needle under viscoelastic is then done. Hydrodissection is subsequently done. Phacoemulsification is then started using the karate chop technique. The nucleus is first chopped into four quadrants by a karate chop technique before being phacoemulsified. Irrigation and aspiration are done to remove any residual cortex. A posterior chamber IOL is then implanted in the capsular bag.

Completing the trabeculectomy

Shifting back to trabeculectomy, the partial-thickness scleral flap is then lifted. A deeper full-thickness scleral flap 2 mm by 2 mm is excised using an Agarwal punch. Then, a peripheral iridectomy is performed. The external scleral flap is reposited back and is closed by two radial 10-0 nylon sutures applied at both the corners. Tenons membrane and conjunctiva were repositioned back to the limbus using one or two 10-0 nylon sutures. The clear-corneal incision is closed with a 10-0 suture to prevent shallowing of the anterior chamber. The sutures are removed after a week.

Postoperative care

All patients are treated with tobramycin (0.3%)–dexamethasone (0.1%) eye drops four times a day for 1 month postoperatively, and then the dosage is gradually tapered over a period of 2 weeks. The patients were examined on the first postoperative day, once weekly for 1 month and once monthly for the first 3 months. Additional follow-ups are provided whenever indicated.

Eye with cataract and glaucoma. Superior rectus secured to give good exposure superiorly.	Fornix-based conjunctival flap made. Wet field cautery being done.
5 by 4-mm scleral flap being made with a scleral dissector.	5 by 4-mm scleral flap being made with a scleral dissector up to the corneoscleral junction.
Scleral flap lifted.	26-ga needle injecting viscoelastic inside the eye. Note the trabeculectomy flap is superior, and this incision is temporal.
Clear-corneal incision. Note the straight rod inside the eye in the left hand. The right hand is performing the clear-corneal incision. This is a temporal incision, and the surgeon is sitting temporally.	Rhexis being done with a needle rhexis started from the center, moved to the right and then down. Rhexis should not be started from the center, moved to the left and then downward.
Phaco probe placed at the superior end of the rhexis.	Karate chopping being performed
Final bits of nucleus removed.	Nucleus fully removed.

Discussion

Trabeculectomy combined cataract extraction is now gaining popularity in treating patients with coexisting POAG and cataract because of its encouraging results. Trabeculectomy combined extracapsular cataract extraction corrected both of the above problems in one sitting. But, there is a high incidence of postoperative hypotony, choroidal detachment and hyphaema.

The later advancement in small-incision cataract surgery, phacoemulsification, is found to give good results and has a lower incidence of the above complications. The combined procedure has been shown to improve both visual acuity and lower IOP in many patients. Performing both procedures at the same sitting is more convenient for patients, decreases the frequency of postoperative pressure spikes and decreases the number of glaucoma medications required to control IOP in many patients. Other advantages of combined surgery include more rapid visual recovery and lower cost compared to a two-stage surgery. This can be either done by a single-site or a two-site approach.

A leaking wound will be effective for a trabeculectomy, whereas a watertight closure is required for a cataract. This two-site procedure helps to achieve both. Temporal clear-corneal phacoemulsification combined with a separate superior trabeculectomy involves fewer manipulations of conjunctiva and sclera in the region of trabeculectomy. The possible induced inflammation from the phacoemulsification tip is in a separate quadrant from that of the trabeculectomy flap. In addition, the separate site facilitates the use of a fornix-based conjunctival flap for the trabeculectomy. The two-site procedure also has decreased pooling of fluid and facilitates surgery on patients who have prominent brows. Two-site trabeculectomy combined phacoemulsification has been found to give a better pressure-lowering effect and a lesser need for postoperative medications.

We used STAAR plate haptic silicone foldable IOLs because it has been shown that acrylic lenses are associated with higher mean IOP than silicone lenses. We have not used mitomycin in our study group as it has been shown that mitomycin is not helpful in modifying the surgical outcome. No statistical difference has been found between control and mitomycin groups of non-selected patients with POAG in the overall success rate of trabeculectomy procedure. Also, mitomycin C supplemented with the combined surgical procedure also has been shown to have the potential for complications like hypotony, filtering bleb leaks and fibrin in the anterior chamber, and chronic hypotony-induced maculopathy and endophthalmitis.

Our study confirms the earlier reports that combined procedures produce lower IOP and have a lesser need to continue postoperative medications. Our study shows that combined trabeculectomy and phacoemulsification lead to low astigmatism and early stabilization of refraction and visual rehabilitation because of its small incision.

A separate two-site combined trabeculectomy with phacoemulsification appears to be a safe and effective surgical approach for visual rehabilitation and IOP control in patients with concurrent cataract and glaucoma.

Cortical aspiration completed. Note the straight rod in the left hand, which helps control the movements of the eye.	PC-IOL being implanted.
Agarwal punch starting to create a trabeculectomy opening.	Trabeculectomy opening complete.

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