Completing phaco following anterior capsular tear
Article Outline
- Abstract
- 1. Introduction
- 2. Conversion to extracapsular extraction
- 3. Anterior chamber phacoemulsification
- 4. Endocapsular phaco in the presence of a primary capsulorrhexis tear-out
- 5. Endocapsular phaco in the presence of secondary anterior capsular tear
- 6. What to do in the case of a “red hole” in the nucleus
- Disclosures
- Conflict of interest
- Financial Support (Grants)
- Proprietary Interest
- References
- Copyright
Abstract
A primary tear-out of the capsulorrhexis or a later anterior capsule tear occurs in less than 1% of phacoemulsification procedures (Marques et al., 2006). It is a relatively uncommon complication but a hazardous and important one, although comparatively little has been published on its management. With the nucleus still in the bag at this stage, the surgeon is faced with the sizeable challenge of completing surgery without propagating a wrap-around tear to the posterior capsule.
These are perilous conditions to face, but by using the right techniques the surgeon can still prevail. There is a clear set of principles that are based on self-knowledge of the surgeon’s own skills and experience, combined with their understanding of how to control the forces acting on the tear and the tolerances of the capsular bag to surgical manipulation.
Applying these principles in practice has enabled the development of a range of techniques now available to safely remove the nucleus under these challenging conditions. However, by far the most important principle of all is that if in doubt, not to proceed.
Keywords: Phacoemulsification, Anterior capsule tear
1. Introduction
The main overarching principle when dealing with an anterior capsular tear early on during phaco is to do what is safest in your hands. For many of us that might reasonably be nothing except just close the eye. There is absolutely no shame in doing this, and only credit is due for having the humility to know your limitations and taking the course of action that is most likely to result in the best possible visual outcome for your patient.
If you are inexperienced or lack the confidence to continue, you should willingly hand over the case to someone who is more experienced and more likely to succeed. Watch what they do and learn from it. No one will ever thank you, nor should they, for continuing against the odds and ending up with a dropped nucleus or worse.
So having made this first binary choice to go ahead with surgery there are a number of techniques to consider. The surgeon should try to make their choice systematically, bearing in mind their level of experience and also the availability of the correct instruments together with ophthalmic viscosurgical devices (OVDs) and an appropriate IOL.
There are principally three choices; conversion to extracapsular extraction, performing anterior chamber phacoemulsification or continuing with endocapsular surgery.
2. Conversion to extracapsular extraction
Traditionally extracapsular conversion is performed by extending the incision circumferentially along the peripheral cornea or limb us in either direction followed by dislocation of the nucleus out of the bag (with relieving anterior capsular cuts if required) and, finally, expressing it from the eye.
A more recently available option is to extend the incision into a “frown” configuration that forms the back edge of a wide scleral tunnel as used in Manual Small Incision Cataract Surgery (MSICS). Such a wound if well constructed can be left sutureless and it induces less corneal astigmatism than the conventional circumferential incision thereby yielding better uncorrected vision (Gogate et al., 2003). The nucleus is then dislocated out of the bag and either hydroexpressed or viscoexpressed through the tunnel.
The traditional instrument used for nucleus extraction in extracapsular surgery has been the irrigating vectis loop. This is still the preferred choice for many surgeons. However, the alternative technique of viscoexpression is safe, effective and less traumatic for delivering the nucleus. This relatively gentle technique works best by injecting a dispersive OVD (usually methylcellulose) with the cannula positioned beneath and inferior to the anteriorly prolapsed nucleus. The proximal shaft of the cannula is used to depress the back edge of the wound so that further injection of OVD provides additional pressure to control the steady delivery of the nucleus through the scleral tunnel (Fig. 1). Hydroexpression can also be used to the same effect, using hydrostatic pressure generated either from the irrigating bottle via an anterior chamber maintainer (Blumenthal’s Mini-Nuc technique (Blumenthal et al., 1992)) or manually using a syringe and cannula.
Figure 1.
Controlled delivery of the nucleus through the incision by viscoexpression.
The other surgical options all involve continuing with phacoemulsification.
3. Anterior chamber phacoemulsification
The first ever phacoemulsification performed by Dr. Charles Kelman in 1967 was carried out in the anterior chamber. There were no viscoelastics/OVDs in those days so the corneal attrition rate through endothelial cell damage was high.
Nowadays we have available a wide range of OVDs, together with more refined fluidics, microsurgical instruments and techniques. It has been shown in a prospective randomized controlled trial that the endothelial cell loss using current anterior chamber techniques is no worse than during endocapsular phacoemulsification, at around 11% (Alio et al., 2002). This technique involves dislocating the nucleus into the chamber using hydrodissection and then, with copious use of sodium hyaluronate and hydroxypropyl methylcellulose, the nucleus is emulsified using a stop-and-chop technique.
4. Endocapsular phaco in the presence of a primary capsulorrhexis tear-out
When you are faced with an early primary tear-out of the capsulorrhexis, which occurs always prior to hydrodissection (Fig. 2), it is still possible to use an endocapsular technique for phacoemulsification with a good chance of success. This involves substantially debulking the central nucleus without using hydrodissection. In the presence of a rhexis tear-out any attempt at hydrodissection or even gentle hydrodelineation stands a very high chance of extending the capsular tear around the equator, often explosively.
Figure 2.
Early primary tear-out of the rhexis that occurred before hydrodissection.
Debulking the nucleus has two main benefits. First, as central grooving of the nucleus progresses, the ports on the irrigating sleeve of the phaco tip begin to descend below the level of the edge of the rhexis. The irrigating fluid then flows under the capsule and assists in gradually loosening the cortico-capsular attachments—a sort of “auto-hydrodissection”. Second, the bowling out of the central nucleus allows the thin sidewalls of the bowl to be readily collapsed inwards on themselves using a combination of gentle viscodissection and horizontal mechanical chopping—actually more like centripetal “dragging” rather than chopping—of the anterior wall. The remaining nucleus can be moved into the safe central area or prolapsed forward and then phaco-aspirated under a dispersive OVD. Some surgeons prefer a single-handed technique at this stage because it facilitates greater chamber stability due to the absence of sideport leakage associated with a second instrument (Fig. 3, Liyanage et al., 2009).
Figure 3.
A one-handed technique results in greater chamber stability.
With particular care, safe implantation of a foldable lens inside the capsular bag is possible in these cases. The haptics should be oriented perpendicular to the tear in order to achieve good lens centration together with a minimal risk of haptic dislocation. However, we need to be aware that the commonest stage at which the anterior capsular tear is propagated posteriorly is during endocapsular implantation of the IOL, so great care needs to be taken in order not to over-distend the bag (Marques et al., 2006).
5. Endocapsular phaco in the presence of secondary anterior capsular tear
A secondary capsular tear is one that is made at any time after completion of a continuous capsulorrhexis. Usually this type of tear occurs after the start of phaco, either from the second instrument or the phaco tip. Because hydrodissection has already been performed it is slightly easier to deal with this situation compared with a primary tear-out described above because now the nucleus is already mobile in the bag. However, it should be clearly stated at the outset that endocapsular phaco in this situation is still relatively hazardous because of the significant risk of posteriorly extending the anterior capsular tear; this is particularly so with a dense cataract. In this situation it is vitally important not to apply any centrifugal (radially outward) forces because these will tend to propagate the tear around the equator. Even when the central posterior plate is thinned right down, the considerable radial excursions often necessary to definitively divide the nucleus will inevitably contribute to extending the tear (Fig. 4). With a mature cataract and a compromised anterior capsule, even just debulking the nucleus in the bag can be hazardous. So in this situation can be safer and easier to mechanically dislocate one edge of the nucleus and tilt it forward. In this position, the equatorial edge can then be emulsified in the iris plane and gradually chipped away and reeled in by the phaco tip safely, rotating it like a carousel.
Figure 4.
Radial excursions used to divide the nucleus may cause the tear to extend.
If the posterior capsule is ruptured there are two useful telltale “nuclear” signs that appear: (a) the nucleus rapidly decenters and (b) it no longer rotates, having done so previously. If persistent attempts to rotate the non-rotating nucleus continue, it will inevitably dislocate posteriorly. All this can be avoided in the first place through an earlier extracapsular conversion or, perhaps more wisely, an elective extracapsular procedure when faced at the outset with a dense cataract.
6. What to do in the case of a “red hole” in the nucleus
If you are a little too aggressive during bowling of the nucleus, you can all too easily create the infamous red hole through the floor of epinucleus (Fig. 5). The underlying lens capsule tends to remain intact if the red hole is created principally by “pulling” on the epinucleus with aspiration, rather than by “pushing” excessively with the phaco tip which is much more likely to penetrate the underlying posterior capsule. The most sensitive method for identifying the presence of vitreous prolapse in this situation is to use triamcinolone (Burk et al., 2003). Added insurance to reduce the risk of vitreous prolapse is provided by the use of a BSS–OVD exchange before removing the phaco tip from the eye. This prevents chamber collapse by tamponading any positive vitreous pressure thereby reducing the risk of extension of the anterior capsular tear (Angunawela and Little, 2008). A balancing relieving cut can then be made in the rhexis, if judged necessary, opposite from the original tear. The nucleus is then readily prolapsed forward using a combination of mechanical lift with the chopper and injection of OVD behind the nucleus. It can then be dialed forwards into the anterior chamber. With a dispersive OVD to protect the endothelium, the nucleus can be removed single-handedly in the iris plane to minimize chamber fluctuation, leaving the posterior capsule intact with diametrically opposing tears in the rhexis (Fig. 6).
Figure 5.
A red hole through the floor of the nucleus is visible.
Figure 6.
The posterior capsule is intact with diametrically opposite tears in the rhexis.
Liberal use of OVD is essential in all these techniques; it serves to protect the endothelium, tamponade the posterior capsule, and reduces overall the risk of a wrap-around tear.
The presence of a primary or secondary anterior capsular tear is a hazardous complication to have to deal with early on during phacoemulsification. However, armed with a few clear principles, a copious supply of OVD and the correct instruments there are a number of special techniques that enable safe removal of the cataract and implantation of a lens in the capsular bag, or the ciliary sulcus, without posterior extension of the capsular tear.
The most important principle of all is to choose whatever the safest option in your hands is. Remember the maxim; “If in doubt, don’t do it,” and always ask for help when you need it. Our main priority must be to ensure the best possible outcome for our patients. We should also routinely offer a prompt explanation and apology to all patients following any adverse event. Make friends with your mistakes. People are reluctant to sue someone that they like and trust (Gorney, 1999).
Disclosures
None
Conflict of interest
None
Financial Support (Grants)
None
Proprietary Interest
None
References
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PII: S1319-4534(10)00048-2
doi:10.1016/j.sjopt.2010.03.005
© 2010 Published by Elsevier Inc.
