This article is more than 5 years old. Information may no longer be current.
‘Inside-out’ technique delineates central core nucleus
Fluid is injected from the central core of the nucleus to the outside.
Eyes with a posterior polar cataract are predisposed to posterior capsule dehiscence during cataract surgery. In such eyes, the recommended surgical strategy is to avoid cortical cleaving hydrodissection. Instead, conventional hydrodelineation is performed. Even with the latter, there remains a possibility of fluid being injected inadvertently in the subcapsular plane, leading to unwarranted hydrodissection.
To prevent this complication, we propose a technique to precisely delineate the central core nucleus. We have termed this “inside-out delineation.”
Surgical technique
After performing continuous curvilinear capsulorrhexis, a central trench is sculpted. A specially designed right-angled cannula is mounted on a 2-cc syringe filled with fluid. The cannula penetrates the central lens substance through right wall of the trench. The fluid is then injected rapidly. A delineation is produced by the fluid, which traverses from inside to the outside. The plane of injection is decided depending upon the density of the cataract. As this is done under direct vision, a desired thickness of nucleus-epinucleus cushion can be achieved.
|
Images courtesy of Abhay R. Vasavada, MD, FRCS. | ||
A golden ring within the lens is evidence of successful delineation (Figure 1). Fluid injection may be repeated in the left wall of the trench with another right-angled cannula. The central nucleus can be consumed within the nucleus-epinucleus bowl using an appropriate technique.
Depending on the density of the cataract, we prefer to use the slow-motion technique proposed by Robert Osher, MD, or the step-by-step chop in situ and lateral separation technique developed by us.
Discussion
In this technique, delineation is produced by injecting fluid from the central core of the nucleus to the outside, unlike the conventional technique, where fluid is injected from the outside to the inside. With the latter, there is a possibility of inadvertent subcapsular injection in an attempt to delineate. This can lead to posterior capsule rupture.
With our technique, the surgeon has the option to inject fluid in the desired plane for cleaving the nucleus with precision. As this is done under direct vision, it provides superior control. This is particularly important for emulsification of posterior polar cataracts.
With the right-angled cannula, the fluid jet is directed perpendicular to the lens fibers, which cleaves the fibers more effectively than against a curved cannula (Figure 2). With the inside-out delineation, it is possible to produce more than one cleavage plane in the wall of the trench by injecting fluid at various depths.
We employed this technique in 25 consecutive eyes with a typical posterior polar defect. The incidence of posterior capsule rupture was two out of 25 (8%). This is less than what was reported earlier.
Moreover, using a conventional delineation technique in a dense cataract, it is difficult to introduce the cannula to a significant depth to achieve a thick epinucleus bowl/cushion. It can be accomplished with less difficulty by using the inside-out technique. The resulting thick nucleus- epinucleus bowl gives additional safety in these cataracts, where aggressive phaco-parameters are necessary for their removal.
We envision the potential of this technique in emulsification of traumatic cataracts with existing posterior capsule rupture.
The limitation of this technique is that sculpting is a prerequisite for its implementation.
In a nutshell this technique enables the surgeon to precisely achieve delineation of the nucleus of a desirable size.
For Your Information:
- Abhay R. Vasavada, MS, FRCS, and Shetal M. Raj, MS, can be reached at Iladevi Cataract & IOL Research Centre & Raghudeep Eye Clinic, Gurukul Road, Memnagar, Ahmedabad-380 052, India; +91-79-749-2303 or 749-0909; fax: +91-79-741-1200; e-mail: shailad1@sancharnet.in.