EyeWorld Asia-Pacific December 2012 Issue

32 EWAP Cataract/IOL December 2012 Cortical cleaving hydrodissection I. Howard Fine, MD, describes his technique in detail, step by step F ollowing the completion of a capsulorhexis through a sideport incision, we perform gentle cortical cleaving hydrodissection. 1 Hydrodissection of the nucleus in cataract surgery has traditionally been perceived as the injection of fluid into the cortical layer of the lens under the lens capsule to separate the lens endonucleus and epinucleus from the cortex and capsule. 2 With increased use of continuous curvilinear capsulorhexis and phacoemulsification in cataract surgery, hydrodissection became a very important step to mobilize the nucleus within the capsule for disassembly and removal. 3-6 Following nuclear removal, cortical cleanup proceeded as a separate step, using an irrigation and aspiration handpiece. I first described cortical cleaving hydrodissection, which is a hydrodissection technique designed to cleave the cortex from the lens capsule and thus leave the cortex attached to the epinucleus. 1 If cortical cleaving hydrodissection is performed correctly, it lyses the connections between the cortex and the equator of the lens capsule resulting in greater ability to rotate the cataract and dramatically facilitates cortical clean-up. In fact, by I. Howard Fine, MD Views from Asia-Pacific Prema PADMANABHAN, MD Medical Director, Director, Department of Cornea & Refractive Surgery Sankara Nethradaya Medical Research Foundation 18 College Road, Chennai – 600 006, Tamil Nadu, India Tel. no. +91-44-28271616 Fax no. +91-44-28254180 drpp@snmail.org W hen Faust 1 first introduced the term “hydrodissection”, the intent was to facilitate the expression of the nucleus from the capsular bag in extracapsular cataract extraction. Later, surgeons performing phacoemulsification used the same term to describe their technique of injecting fluids into the cortical layer to mobilize the nucleus within the capsular bag. It was Howard Fine, MD, 2 who modified the technique—and the term—to achieve a different objective, which was to loosen corticocapsular adhesions rather than merely mobilizing the nucleus. This article is a step-by-step description of cortical cleaving hydrodissection—which, in the words of the legendary David Apple, “has quietly emerged as one of the numerous stellar achievements and improvements in cataract surgery.” 3 Although every cataract surgeon must have observed the presence of corticocapsular adhesions and faced the challenges posed by them, the exact nature and mechanism of these adhesions remains poorly understood. It has been hypothesized that the accumulation of secretory extracellular material from the mitotically active lens epithelial cells is what results in corticocapsular adhesions. 4 Whatever be their etiopathogenesis, failure to release them prevents lens rotation. A forceful attempt to rotate the nucleus could then result in capsular zonular dialysis. There are a few key words and phrases in the description of the technique that merit attention. First, this is meant to be a gentle procedure, with decompression following the injection of each aliquot. A gentle depression with the shaft of the cannula spreads the fluid, between the cortex and posterior capsule and ensures that fluid does not remain trapped posteriorly. The first sign of entrapment is the widening of the capsulorhexis margin. Failure to recognize this sign could result in what has been colorfully described by Yeoh et al. 5 as “pseudo-expulsive haemorrhage”. A small capsulorhexis as pointed out by Dr. Fine makes cortical cleaving hydrodissection easier to perform. On the other hand, a small capsulorhexis also makes it more difficult for posteriorly trapped fluid to escape, increasing the risk of pseudoexpulsive haemorrhage. Optimizing the size of capsulorhexis must therefore strike the right balance between surgical ease and hydrodynamic safety. Cortical cleaving hydrodissection may not be possible or even desirable in certain situations. Tenacious adhesions may resist the advancing fluid wave. If the continuity of the capsulorhexis is not intact, the forward bulge of the nucleus in response to the posteriorly advancing fluid wave may cause further extension of the capsular tear. A posterior polar cataract could result in a rupture of the already weak posterior capsule. In such situations, a guarded viscodissection may be useful in creating a protective “cushion” between the nucleus and the capsule. A word of caution in eyes with advanced brunescent cataracts, where the epinuclear shell is almost nonexistent and cortical material is scant. A cortical cleaving hydrodissection loosens the sparse cortical covering of the brunescent nucleus. Extreme care must be exercised while emulsifiying the last fragment of the nucleus because by then the rest of the capsular bag is virtually empty and the risk of the posterior capsule being sucked into the phaco port is high. Although the primary objective of the cortical cleaving hydrodissection was to loosen corticopasular adhesions, a “spin-off” advantage of vital importance was not even realized until it was explicitly pointed out by David Apple.3 In his own words: “Based on our lab research, we have recently identified 6 important factors in reducing posterior capsule opacification. Hydrodissection, specifically subcapsular or cortical cleaving hydro dissection is the first of these factors. This method, described by Fine in 1992 is precisely what is needed to achieve this long term goal.” Can any surgeon or surgical technique boast of a more powerful testimonial? References 1. Faust DJ. Hydrodissection of soft nuclei. Am Intraocular Implant Soc J. 1984;10:75-77. 2. Fine IH. Cortical cleaving hydrodissection. J Cataract Surg. 1992;18:508-512. 3. Apple DJ. Peng Q. J Cataract Surg. 2000;26(7):943-944. 4. Vasavada AR, Dholakia SA, Raj SM, Singh R. Effect of cortical cleaving hydrodissection on posterior capsule opacification in age-related nuclear cataract. J Cataract Refract Surg. 2006 Jul;32(7):1196-200. 5. Yeoh R, Theng J. Capsular block syndrome and pseudoexpulsive haemorrhage. J Cataract Refract Surg. July 2000;26:1082-1084. Editors’ note: Dr. Padmanabhan has no financial interests related to her comments.