The learning curve for cataract surgery is steep and ophthalmologists need many years to achieve a level of expertise that can rescue them from most tough situations. This case is performed with a resident surgeon in the last year of training and it is done with the supervision of a professor level surgeon.
The primary error is excessive hydro-dissection in the setting of a small capsulorhexis which leads to iris prolapse and a blown-out, ruptured posterior capsule. The idea was good: given the patient’s history of Flomax (tamsulosin) use, prolapse the nucleus partially out of the capsular bag. I do this technique quite often, but in order for it to be successful, the capsulorhexis must be sufficiently large, at least 5 mm and preferably 5.5 mm in diameter.
Here, we have about a 4 mm capsulorhexis and when the nucleus would not prolapse out of the bag, even more balanced salt solution was injected. This finally did bring the nucleus out of the bag but it also caused the iris to prolapse out of the incision and it ripped open the posterior capsule. The iris was reposited by equalizing the pressure gradient behind and in front of the iris stroma by releasing fluid and viscoelastic. The ruptured posterior capsule was not noted until mid-way into the phacoemulsification of the nucleus. We did not see the “snap sign” that was visible in a similar case that we featured last year.
In most cases of posterior capsule rupture, the rule is to avoid pulling the phaco probe out of the eye because when we de-pressurize the anterior chamber, it allows vitreous to prolapse. In a recent case, we showed how to keep the anterior hyaloid face intact and complete the case without vitreous prolapse.
This case is different: here we note that the nucleus is already descending and there is a noticeable gap between the iris and the lens material. There is already vitreous prolapse and we intentionally pull the phaco probe out of the eye and allow the anterior chamber to de-pressurize which causes the descending nuclear pieces to come up to the iris plane. If the nuclear pieces are engulfed in vitreous, then this procedure will not work and you are better off sending the patient for a pars plana lensectomy and vitrectomy by a retinal specialist.
Plenty of dispersive viscoleastic is injected behind the nuclear pieces and they are brought up into the anterior chamber and phaco-aspirated from the eye. More viscoelastic is injected to create a barrier to keep vitreous back and the cataract pieces supported.
Once the nuclear pieces are stabilized, you should evaluate the level of anesthesia for the patient. In our case, the patient was given a retro-bulbar block prior to the cataract surgery. While I will do 99+% of patients with just topical / intra-cameral anesthesia, the residents who are in their training benefit from giving patients a retro-bulbar block since it gives deeper local anesthesia as well as akinesia. The patients are also more comfortable for the procedure which can last longer. If you are doing a cataract surgery under topical anesthesia and you have a complication like this, you will need to augment the anesthesia. Options include giving more intra-cameral anesthesia, having the anesthesiologist administed additional intra-venous systemic medications (such as midazolam for sedation and fentanyl for pain control), doing a sub-Tenon’s approach to give retro-bulbar anesthesia, or a combination of these options.
The bimanual 23g anterior vitrectomy instrumentation is used to do both the cortical clean-up as well as the anterior vitrectomy. There is an important distinction between the two anterior vitrectomy modes on your phaco machine:
- I/A Cut: This means that your foot pedal does: position 1 irrigation, position 2 aspiration, position 3 the mechanical cutting action. This is great for aspirating cortex material or removing viscoleastic at the end of the case. Do not use this mode for removing vitreous since it will put traction on the vitreous and that could damage the retina. If you hear the ding sound that the machine makes when it is occluded, you likely have vitreous blocking the port and you should not be using this mode.
- Anterior Vitrectomy: This means that your foot pedal does: position 1 irrigation, position 2 mechanical cutting action, position 3 aspiration. This is great for removing prolapsed vitreous, but it does not work well for stripping away cortex material. Also, be careful as this mode can easily damage the remaining capsular support or even the iris.
Triamcinolone is also used to help visualize the prolapsed vitreous because it sticks to the surface of the vitreous strands. It also has a good anti-inflammatory activity which is helpful in healing after cataract surgery with complications like this.
The three-piece IOL is placed in the sulcus with the appropriate power calculated by the rule of nines. In this case, the anterior capsular rim is intact so there is plenty of support for the sulcus IOL. The main incision is then sutured shut. Yes, you should suture the incision in a case where you’ve had this complication because if your incision leaks, then vitreous can prolapse into the anterior chamber and the IOL can become dislocated.
Finally, the bimanual anterior vitrectomy instruments are used to remove the viscoelastic from the anterior segment using the I/A Cut mode (you could also even use the regular irrigation/aspiration mode with these hand-pieces).
This patient did very well and even had reasonably good vision on post-op day 1. One day you will have a very similar case and I trust that the lessons learned from this case will help you to rescue the situation and provide a good outcome for your patient.
Click below to learn from the great case (13 minutes long):
All content is (C) 2019 by Uday Devgan MD. All rights reserved.
2 Comments