The Curse of the Baby Rhexis

baby rhexis title
You must avoid the curse of the baby rhexis!

This case is brought to you in conjunction with EyeGuru.org, an excellent resource for both ophthalmologists in training and ophthalmologists in practice. This case features a capsulorhexis which is too small (the “baby rhexis”) and that causes a number of problems which result in a ruptured posterior capsule and a displaced IOL. Watch the video and you’ll see that it all started with the Curse of the Baby Rhexis.

The small capsulorhexis makes is very difficult to remove the cataract pieces from the confines of the capsular bag. The central nucleus is about 4 mm thick but the peripheral lens nucleus is much thinner as we move toward the lens equator. Another challenge here is that the decision is made to do a single-width groove and then split the nucleus into two halves. Each half is quite bulky and is difficult to bring out via the baby rhexis.

What would have been a better option?

  • we should have made a bigger capsulorhexis to begin with
  • do a double-width groove when dividing the nucleus to debulk it further
    • a single-width groove removes 10% of the nucleus so each remaining half is 45% (10% + 45% + 45% = 100%)
    • a double-width groove removes 20% of the nucleus so each remaining half is 40% (20% + 40% + 40% = 100%)
  • do a full four-quadrant divide-and-conquer technique
    • two crossing grooves remove 10% + 10% of the nucleus, so each remaining quadrant is about 20% (10% + 10% + 20% + 20% + 20% + 20% = 100%)
  • chop the nucleus in the capsular bag into small fragments
  • debulk the central nucleus after making two halves before attempting to pull them out of the capsular bag

Once the capsular bag has been ruptured and we clearly see that the posterior capsule hole matches the size of the phaco tip, we must accept reality.

Hole in Posterior Capsule

At this point, the chopper should be removed from the eye with the phaco probe kept inside the eye, not allowing the anterior chamber to collapse. Now with the left hand, place a sufficient aliquot of dispersive viscoelastic into the posterior capsule hold to plug it up and prevent vitreous prolapse.

The same technique applies when the phaco probe or I/A probe is brought out of the eye: do not allow the anterior chamber to depressurize or collapse since that will allow vitreous prolapse.

Another aspect of facing reality is to stop and switch to a three-piece IOL since it allows more flexibility for placement. But in this case, denial was too strong of a force and the surgeon still attempts to implant the single piece IOL in the capsular bag. The existing posterior capsule rupture extends, we notice small cataract chips in the anterior vitreous, and the single-piece IOL is dislocated and precariously positioned in the eye. There is a strong chance that in the future this eye will need to undergo an IOL exchange.

Lots of great learning in this case. Be sure to watch it in detail. And check out eyeguru.org which is a fantastic site for both surgeons in training and surgeons in practice.

(post script: When I watch the video again, I note that the posterior capsule rupture happens even earlier than I state in the video — it happens in a fraction of a second when the left half of the nucleus is first being engaged with the phaco probe.)

 

 

 

 

 

 

 

 

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