August 2008

 

CATARACT/ IOL

 

Mastering bimanual


by Matt Young EyeWorld Contributing Editor 

 

 

Surgeon shares 12 steps to make this approach easier

A new technique may make bimanual microincision cataract surgery easier to perform Source: Jorge L. Alio, M.D.

Advocates of bimanual microincision surgery still always note a considerable learning curve related to mastering the technique. Now, a group of Indian researchers suggest that learning curve can be minimized in 12 easy steps.

Published in the March/April 2008 issue of the Indian Journal of Ophthalmology, “Learning micro incision surgery without the learning curve” is a compelling read. Thomas Ravi, M.D., LV Prasad Eye Institute, Andhra Pradesh, India, suggested using a large-bore or standard anterior chamber maintainer (ACM) to facilitate learning without changing one’s machine or surgical technique. More precisely, Dr. Ravi’s technique consisted of the following: • Use a formal “block” while in the learning stage. • Employ a 20-guage myringotomy blade to make a paracentesis incision in the upper temporal quadrant at the 10 o’clock position. This is used mostly for phacoemulsification. • Deepen the chamber with your preferred ophthalmic viscosurgical device (OVD). • Perform a capsulorhexis as usual with a bent needle through the paracentesis incision. • Use the myringotomy blade to perform another 1.5-mm paracentesis (at 6 o’clock or a slightly longer one at 7 o’clock), which is used to insert the ACM. The ACM attached to irrigating fluid is then inserted, and the stop-cock is opened. “Whatever the ACM used, the higher the bottle height, the better,” Dr. Ravi noted. • Make a paracentesis incision about 90 degrees away from the phaco incision. • Cut off the sleeve for the phaco needle, so the sleeveless needle can be inserted into the anterior chamber through the supero-temporal incision. “The irrigating chopper or preferred instrument is introduced through the incision created for this purpose,” Dr. Ravi reported. Phaco can be performed using the preferred technique. • Extract the cortex with a single port aspiration cannula attached to a syringe. “The availability of two incisions allows easy access to the cortex that might otherwise be difficult to access,” Dr. Ravi noted. • Insert an endo-capsular ring into the capsular bag. • If the wound hasn’t been enlarged to inject the capsular ring, it should now be used to place the IOL. • Aspirate the OVD using a single port cannula. • The ACM is removed and the incisions hydrated “to achieve a watertight wound,” Dr. Ravi reported. “For those who are familiar with the use of the ACM for the Blumenthal technique and have used it for phacoemulsification too, this switch from regular phacoemulsification to MICS is literally without a learning curve,” Dr. Ravi wrote. The ACM itself is a real boon to cataract surgery, the author noted, as it prevents corneal burns. “In fact, since starting phacoemulsifcation in 1992, the author has not had a single corneal burn,” Dr. Ravi reported. “We attribute this to the use of the ACM.”

Dr. Ravi did suggest that this technique to learn bimanual microincision surgery should be used by “reasonably experienced” surgeons. “Experience with the use of the ACM is desirable and easily obtained,” Dr. Ravi reported. “For a surgeon familiar with the use of the ACM or willing to try its use in phacoemulsification, performing MICS should not require additional expert assistance.”

Dr. Ravi did mention that the complication rate with this technique could be as high as 28%, although his experience has been much better. A risk of complications for the reward of easing into bimanual microincision surgery could be worthwhile. Then again, some advocates of the coaxial phacoemulsification approach have suggested after initial hype surrounding bimanual phacoemulsification, the tide is once again turning against the procedure. Sam Fulcher, M.D., Temple, Texas, doesn’t get involved in bimanual/coaxial politics, but he does enjoy the benefits of the coaxial technique and doesn’t plan on changing anytime soon. “The technique I’m currently using I like and works well,” Dr. Fulcher said. In fact, Dr. Fulcher said he’s still performing scleral tunnel surgery covered with conjunctiva at the conclusion, which also differs from the trend toward clear corneal incisions. “I did clear corneal briefly and went back to scleral tunnel,” he said, because he thinks it’s a safer incision and leaks less. “Another advantage of scleral tunnel is that it’s removed from the cornea. Further away from the cornea means less astigmatism induction. It’s gentler on the corneal endothelium too.”

Dr. Fulcher is a bit of a maverick in this regard, or perhaps a throwback to earlier days of cataract surgery. In his practice, there are 10 ophthalmologists, and only two perform scleral tunnel surgery. “But I’ve never had a case of infectious endophthalmitis,” he said. “And they [the clear corneal majority] acknowledge that our rates of endophthalmitis are less. For them, it’s an accepted risk.”

Dr. Fulcher suggests that trends aren’t always wise to embrace, whether they’re bimanual ones or clear corneal ones. “I don’t intend to change,” he said.

Editors’ note: Dr. Ravi has no financial interests related to this study. Dr. Fulcher has no financial interests related to his comments.

Contact Information

Fulcher: 254-724-2111, sfulcher@swmail.sw.org

Ravi: rt@ravithomas.com

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