This article is more than 5 years old. Information may no longer be current.
Complications can spur intraop conversion
Click Here to Manage Email Alerts
One reason why I still teach residents the technique of larger-incision manual extracapsular cataract surgery is that there are times when a complication happens during phacoemulsification and conversion to this technique is needed. This technique allows extraction of large cataract pieces without fluidic currents in the eye, even in the presence of a severely compromised capsular bag.
Conversion
The decision to convert from phacoemulsification to the larger-incision extracapsular technique is typically made intraoperatively when a sizable defect in the posterior capsule is noted and large cataract pieces are still inside the eye. In this scenario, continuing to do phaco can send cataract pieces posterior into the vitreous cavity with the fluidic currents and can extend the posterior capsular defect. Once nuclear cataract pieces are engulfed within the vitreous, they can no longer be safely removed from an anterior approach, and a future pars plana vitrectomy and lensectomy will need to be performed instead. The time to decide to convert to manual cataract extraction is before the nuclear cataract pieces begin to descend.
Before withdrawing the phaco probe from the eye, it is imperative that we stabilize and pressurize the anterior segment with viscoelastic. We want to inject plenty of viscoelastic behind the cataract pieces to support them and to create a barrier in front of the anterior hyaloid face and vitreous. Using dispersive viscoelastic, the cataract nucleus can be floated out of the capsular bag and into the anterior chamber. Even more viscoelastic is placed behind the nucleus and then in front of it to recoat the corneal endothelial surface.
The small 2- to 2.8-mm corneal incision that is used for phaco surgery is not sufficiently large for the manual extracapsular technique, and an attempt to enlarge this incision should be avoided. To remove the entire cataract nucleus in one piece, an incision of 8 mm to 10 mm is required, and it is best made in the sclera using a shelf technique to ensure a watertight closure. If the original phaco surgery was being performed under topical anesthesia, it will need to be supplemented with additional medication. Injecting lidocaine in the sub-Tenon or retrobulbar space will ensure a pain-free experience for the patient. The shelf technique involves using a crescent blade to make a scleral incision that has a tunnel length of about 3 mm, extending for the full 8 mm to 10 mm width.
A: This patient is undergoing phacoemulsification surgery via a temporal corneal incision when the posterior capsule is noted to be largely absent. B: The chopper is used to bring the nucleus out of the capsular bag. C: Viscoelastic is then injected behind the nucleus to support it and create a barrier to prevent vitreous prolapse. D: A crescent blade is used to make a superior scleral tunnel in order to manually extract the cataract.
Images: Devgan U
A: The lens loop is placed under the cataract nucleus, which is then removed from the eye. B: Additional viscoelastic is injected to inflate what remains of the capsular bag. C: A cannula is then used to manually aspirate lens cortex material. D: An anterior chamber IOL is placed, and a peripheral iridotomy is performed.
A lens loop is then placed under the cataract nucleus, which is then carefully extracted from the anterior segment. Additional viscoelastic can be injected to float out any remaining cataract pieces. To remove lens cortex material, a controlled approach is to use a 27-gauge cannula on a syringe of balanced salt solution to manually aspirate cortical material. While this approach is slow, it is very controlled and avoids unnecessary fluidic currents in the eye, which could cause prolapse of the vitreous.
Once the cataract pieces are removed, the anterior chamber should be inspected for the presence of vitreous strands using intracameral triamcinolone to stain the vitreous and a miotic agent to bring down the pupil. Any peaking of the pupil is an alert to prolapsed vitreous, and this should be addressed by performing a limited anterior vitrectomy. Additionally, the vitrectomy probe can be used to perform aspiration of remaining cortical cataract material.
Lens implant selection
For lens implant selection, if there is sufficient support of the anterior capsular rim, a three-piece IOL can be placed in the ciliary sulcus. However, if there is any question as to the long-term stability of the sulcus support, an anterior chamber IOL or sutured posterior chamber IOL should be placed instead. While suturing a posterior chamber IOL may seem like a better choice, the anterior chamber IOL actually may have better long-term stability, and multiple studies have shown no difference in visual outcomes between the two choices.
The anterior chamber IOL should be placed in the eye while it is still full of viscoelastic. A small peripheral iridotomy is performed at the same time to prevent pupillary block from the anterior chamber IOL. Once the anterior chamber IOL is in position, the incisions are carefully sutured and the globe stabilized. At this point, small-gauge bimanual irrigation and aspiration can be performed through the sutured incisions in a safe manner to avoid vitreous prolapse. In order to keep the anterior segment pressurized, a larger-bore infusion cannula is used in combination with a smaller-bore aspiration cannula. Alternatively, a manual washout can be done by simply using balanced salt solution on a cannula with one hand while the other hand assists in burping an incision to release the viscoelastic.
At the end of the case, all incisions should be sutured and tested to ensure that they are watertight. Additional medications such as injections of steroids or antibiotics are helpful because these eyes may have a higher risk of postoperative complications such as infection or edema. Finally, because there will be some retained viscoelastic, placing the patient on oral acetazolamide for a few days can help to control the pressure. During the postoperative period, these patients should be watched closely and given a longer course of anti-inflammatory medications compared with uncomplicated phacoemulsification cases.
The technique of converting from phaco to manual extracapsular cataract surgery is not commonly used, but when it is needed, it can make for a better and safer outcome with very good visual outcomes for patients.