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When the capsule breaks and the cataract nucleus drops
All surgeons will experience posterior capsule rupture, so the key is to effectively manage the intraoperative complication.
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You will notice that I have used “when” in the headline of this article and not “if.” That is because each and every cataract surgeon will certainly encounter a ruptured posterior capsule, often with posterior displacement of nuclear cataract pieces, over the course of a career. In fact, it will happen many times, with a reported frequency of posterior capsule rupture of 2% to 5% of cataract surgeries. While the most experienced and talented surgeons can drop this complication rate, it is never 0%, even for them.
With a typical thickness of just 4 µm to 9 µm, the delicate posterior capsule can rupture at many different stages of cataract surgery: A radialized capsulorrhexis can extend to the posterior capsule, hydrodissection can cause a blowout of the posterior capsule, the chopper or second instrument can inadvertently puncture the posterior capsule, the phaco probe can buzz a hole in the posterior capsule, the irrigation and aspiration tip can tear the posterior capsule, and even IOL insertion can damage the fragile posterior capsule.
The risk of sight-threatening complications increases with posterior capsule rupture, with endophthalmitis and cystoid macular edema occurring more often than in a case with an intact posterior capsule. However, when a posterior capsule rupture with a dropped cataract nucleus occurs, it can be effectively managed with a good recovery of vision for our patients.
Preventing posterior capsule rupture
Because we are working in such a small space during cataract surgery, the fluidics from the phaco machine play a critical role in preventing posterior capsule rupture. We can balance the inflow of fluid to the outflow of fluid and make our incisions more watertight in order to prevent fluctuations in anterior chamber stability. We can keep away from the posterior capsule during nucleus removal, and we can use silicone-covered tips during cortex clean-up.
If the posterior capsule is compromised and the cataract nucleus begins to descend posteriorly, we can use viscoelastic to support it and levitate it up into the anterior chamber for removal. Note that if the cataract piece is already entangled in vitreous, this step should be avoided because it could put traction on the vitreous and induce a retinal tear, break or detachment. While others have advocated heroic measures such as a pars plana incision with attempted levitation of a descending nucleus, many times it is easier and safer to have a vitreoretinal surgeon do a complete pars plana vitrectomy and lensectomy at a later time.
When the posterior capsule is noted to be ruptured, the first instinct may be to quickly withdraw the phaco or I&A probe from the eye, but this is frequently a mistake because it will quickly depressurize the anterior chamber and allow vitreous to prolapse forward. Instead, the infusion should be maintained while a dispersive viscoelastic is injected via a paracentesis incision to support cataract pieces, create a barrier to keep vitreous back and pressurize the anterior chamber.
A resident surgeon was in the middle of nucleus removal (a) when he noticed that the posterior chamber suddenly became deeper (b) and the hemi-nucleus fragment started drifting posteriorly. The large nuclear piece then fell back into the vitreous cavity (c), and the characteristic white reflex replaced the red reflex (d). Note that he kept the phaco probe in the eye with the infusion on in order to avoid vitreous prolapse into the anterior chamber.
Image: Devgan U
If a nuclear piece starts to descend into the vitreous cavity, let it go and avoid chasing it. An anterior vitrectomy can be performed to remove prolapsed vitreous and allow IOL insertion. A three-piece IOL should be placed in the sulcus with the option of optic capture. If the IOL is fully in the ciliary sulcus, the IOL power must be adjusted down 0.5 D to 1 D for most eyes, although more for shorter eyes and less for longer ones. If the optic is captured behind the anterior capsulorrhexis, little to no IOL power adjustments need to be made.
Medications to induce pupillary miosis can be instilled to ensure a round pupil without vitreous strands. Triamcinolone is also helpful to stain the vitreous as well as provide inflammation control. Finally, consider suturing the main phaco incision, especially if the eye will need a pars plana vitrectomy.
Medicolegal issues
As long as it is handled properly, a case of a ruptured posterior capsule with dropped cataract nuclear fragments is certainly not malpractice and has limited medicolegal liability. Consider this scenario: A patient goes through the informed consent process and has cataract surgery, during which the posterior capsule breaks and the cataract nucleus drops. The cataract surgeon does not chase after the nucleus, but instead takes time to clear the anterior chamber of vitreous, implant a three-piece IOL in the sulcus, and then notify the patient and his family afterward. The same or next day, he asks his vitreoretinal colleague to see the patient, who is then scheduled for a pars plana vitrectomy and lensectomy. It is a longer road to recovery, but the patient eventually achieves good vision.
This patient was properly informed of the risk of surgery, and one of these known risks happened. The cataract surgeon handled the intraoperative complication well and did not delay in sending the patient to the vitreoretinal surgeon. Complications happen to all surgeons, and while the incidence is low, it will affect a small percentage of our patients. We should work hard to lower our complication rate and strive to become better while providing safer surgery. We have an obligation to do what is best for our patients during these complex situations, but we should not let fear of a complication stop us from helping the millions of patients who benefit from cataract surgery each year.