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Pocket-chop technique for phacoemulsification
CORRESPONDENCE
Pocket-chop technique for phacoemulsification Rosa Braga-Mele, MD, MEd, FRCSC, Zale Mednick, MD Online Video
Chopping techniques in cataract surgery are used to reduce the amount of phacoemulsification energy delivered to the eye during nucleus disassembly.1,2 Chopping uses mechanical energy in place of the ultrasonic energy that is inherent to phacoemulsification. Studies have shown chopping to be associated with less phacoemulsification energy and subsequent corneal endothelial damage than other techniques.1,2 In 1993, NagaharaA described phaco-chop, a technique that uses a horizontal chop to convert a moderate to hard nucleus into 2 heminuclei. The stop-and-chop method, reported in 1994,3 uses a combination of sculpting and chopping to separate the lens into 4 quadrants. Other variations include cross-chop (Kim4), hydro-chop (Braga-Mele and Khan5), and drill and chop.6 We describe a pocket-chop technique, a method of horizontal chopping that is best used for cracking a soft nucleus but can be equally effective in creating space to optimize chopping and cracking in a dense nucleus. SURGICAL TECHNIQUE Following hydrodissection, the phaco needle is introduced into the anterior chamber. Under the sculpt setting with low vacuum, the phaco needle makes several passes proximally from the capsule edge to the center of the nucleus to create a small pocket in this area. The extent of the pocket is approximately one third the depth of the nucleus and 2.0 to 3.0 mm in length (Figure 1). After the pocket is formed, the phaco needle remains burrowed against the pocket and the foot position changes to irrigation. The chopper then enters the eye via the side-port incision and advances to the distal edge of the capsulorhexis. The chopper is embedded in the nucleus at the capsulorhexis edge and brought proximally toward the phaco tip in a horizontal-like chopping motion. The phaco tip provides countertraction as it uses the pocket as a fulcrum. As the chopper reaches the phaco tip, the instruments are moved apart and the lens is chopped into 2 halves. The lens is further divided into 4 quadrants via standard chopping techniques. This technique is demonstrated in Video 1 (available at http://jcrsjournal.org).
Q 2016 ASCRS and ESCRS Published by Elsevier Inc.
Should the initial attempt at the pocket-chop be unsuccessful, the pocket can be easily converted into a longer and deeper groove with the traditional sculpting technique. DISCUSSION The pocket-chop technique possesses several features that distinguish it from standard horizontal chopping. The classic horizontal chop requires the chopper to pass distal to the capsulorhexis edge and engage the nucleus at the equator. This can be a dangerous step as it lends to poor visualization of the chopper in an essentially blind pass into the nucleus. In pocket-chop, because of the firm countertraction provided by the phaco needle at the pocket, the chopper does not have to be advanced to the equator to produce an effective chop. Rather, the chopper embeds the nucleus much more proximally at the edge of the capsulorhexis, a safer and more visible maneuver. Such chopper visibility is similar to that of the combo-chop technique described by Pandit,7 but pocket-chop has the added safety feature of the elongated and deeper initial groove to provide more space. Surgical trainees are often timid when learning chopping techniques, fearful that they will penetrate too deeply with the phaco tip when engaging the nucleus. This can lead to insufficient engagement with the nucleus, rendering any chopping attempt ineffective. With the creation of a pocket, the initial sculpting gives the surgeon a better sense of the nucleus depth. This provides a more controlled entry of the phaco needle into the lens, ensures that the tip is at an adequate depth for a successful chop, and enables the learner to better gauge the depth of his or her chopper tip. As mentioned earlier, if the chop is unsuccessful in cracking the lens, the pocket can be easily converted into a groove. The phaco setting remains in sculpt for softer nuclei and by elongating the pocket, the surgeon can easily alter the technique to stop-and-chop or divide-and-conquer if necessary. REFERENCES
€ u € l M. Comparison of Nagahara 1. Can _I, Takmaz T, C‚akıcı F, Ozg phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques. J Cataract Refract Surg 2004; 30:663–668 2. DeBry P, Olson RJ, Crandall AS. Comparison of energy required for phaco-chop and divide and conquer phacoemulsification. J Cataract Refract Surg 1998; 24:689–692 3. Koch PS, Katzen LE. Stop and chop phacoemulsification. J Cataract Refract Surg 1994; 20:566–570
http://dx.doi.org/10.1016/j.jcrs.2016.09.001 0886-3350
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1532
CORRESPONDENCE
Figure 1. A: A small pocket is sculpted with the phaco piece, approximately one third the depth of the nucleus and 2.0 to 3.0 mm in length. B: The chopper engages the nucleus at the distal capsulorhexis edge and is still visible as it does not advance to the equator. C: The chopper advances toward the phaco tip. D: As the chopper reaches the phaco tip, the instruments move apart in opposing horizontal directions to chop the nucleus into 2 heminuclei.
4. Kim DB. Cross chop: modified rotationless horizontal chop technique for weak zonules. J Cataract Refract Surg 2009; 35:1335– 1337 5. Braga-Mele R, Khan BU. Hydro-chop technique for soft lenses. J Cataract Refract Surg 2006; 32:18–20 6. Kim DY, Jang JH. Drill and chop: modified vertical chop technique for hard cataract. Ophthalmic Surg Lasers Imaging 2012; 43:169–172
7. Pandit RT. Combo-chop nuclear disassembly [letter]. J Cataract Refract Surg 2007; 33:2155
OTHER CITED MATERIAL A. Nagahara K, “Phaco Chop,” film presented at the ASCRS 3rd American–International Congress on Cataract, IOL and Refractive Surgery, Seattle, Washington, USA, May 1993
J CATARACT REFRACT SURG - VOL 42, OCTOBER 2016
Pocket-chop technique for phacoemulsification Rosa Braga-Mele, MD, MEd, FRCSC, Zale Mednick, MD Online Video
Chopping techniques in cataract surgery are used to reduce the amount of phacoemulsification energy delivered to the eye during nucleus disassembly.1,2 Chopping uses mechanical energy in place of the ultrasonic energy that is inherent to phacoemulsification. Studies have shown chopping to be associated with less phacoemulsification energy and subsequent corneal endothelial damage than other techniques.1,2 In 1993, NagaharaA described phaco-chop, a technique that uses a horizontal chop to convert a moderate to hard nucleus into 2 heminuclei. The stop-and-chop method, reported in 1994,3 uses a combination of sculpting and chopping to separate the lens into 4 quadrants. Other variations include cross-chop (Kim4), hydro-chop (Braga-Mele and Khan5), and drill and chop.6 We describe a pocket-chop technique, a method of horizontal chopping that is best used for cracking a soft nucleus but can be equally effective in creating space to optimize chopping and cracking in a dense nucleus. SURGICAL TECHNIQUE Following hydrodissection, the phaco needle is introduced into the anterior chamber. Under the sculpt setting with low vacuum, the phaco needle makes several passes proximally from the capsule edge to the center of the nucleus to create a small pocket in this area. The extent of the pocket is approximately one third the depth of the nucleus and 2.0 to 3.0 mm in length (Figure 1). After the pocket is formed, the phaco needle remains burrowed against the pocket and the foot position changes to irrigation. The chopper then enters the eye via the side-port incision and advances to the distal edge of the capsulorhexis. The chopper is embedded in the nucleus at the capsulorhexis edge and brought proximally toward the phaco tip in a horizontal-like chopping motion. The phaco tip provides countertraction as it uses the pocket as a fulcrum. As the chopper reaches the phaco tip, the instruments are moved apart and the lens is chopped into 2 halves. The lens is further divided into 4 quadrants via standard chopping techniques. This technique is demonstrated in Video 1 (available at http://jcrsjournal.org).
Q 2016 ASCRS and ESCRS Published by Elsevier Inc.
Should the initial attempt at the pocket-chop be unsuccessful, the pocket can be easily converted into a longer and deeper groove with the traditional sculpting technique. DISCUSSION The pocket-chop technique possesses several features that distinguish it from standard horizontal chopping. The classic horizontal chop requires the chopper to pass distal to the capsulorhexis edge and engage the nucleus at the equator. This can be a dangerous step as it lends to poor visualization of the chopper in an essentially blind pass into the nucleus. In pocket-chop, because of the firm countertraction provided by the phaco needle at the pocket, the chopper does not have to be advanced to the equator to produce an effective chop. Rather, the chopper embeds the nucleus much more proximally at the edge of the capsulorhexis, a safer and more visible maneuver. Such chopper visibility is similar to that of the combo-chop technique described by Pandit,7 but pocket-chop has the added safety feature of the elongated and deeper initial groove to provide more space. Surgical trainees are often timid when learning chopping techniques, fearful that they will penetrate too deeply with the phaco tip when engaging the nucleus. This can lead to insufficient engagement with the nucleus, rendering any chopping attempt ineffective. With the creation of a pocket, the initial sculpting gives the surgeon a better sense of the nucleus depth. This provides a more controlled entry of the phaco needle into the lens, ensures that the tip is at an adequate depth for a successful chop, and enables the learner to better gauge the depth of his or her chopper tip. As mentioned earlier, if the chop is unsuccessful in cracking the lens, the pocket can be easily converted into a groove. The phaco setting remains in sculpt for softer nuclei and by elongating the pocket, the surgeon can easily alter the technique to stop-and-chop or divide-and-conquer if necessary. REFERENCES
€ u € l M. Comparison of Nagahara 1. Can _I, Takmaz T, C‚akıcı F, Ozg phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques. J Cataract Refract Surg 2004; 30:663–668 2. DeBry P, Olson RJ, Crandall AS. Comparison of energy required for phaco-chop and divide and conquer phacoemulsification. J Cataract Refract Surg 1998; 24:689–692 3. Koch PS, Katzen LE. Stop and chop phacoemulsification. J Cataract Refract Surg 1994; 20:566–570
http://dx.doi.org/10.1016/j.jcrs.2016.09.001 0886-3350
1531
1532
CORRESPONDENCE
Figure 1. A: A small pocket is sculpted with the phaco piece, approximately one third the depth of the nucleus and 2.0 to 3.0 mm in length. B: The chopper engages the nucleus at the distal capsulorhexis edge and is still visible as it does not advance to the equator. C: The chopper advances toward the phaco tip. D: As the chopper reaches the phaco tip, the instruments move apart in opposing horizontal directions to chop the nucleus into 2 heminuclei.
4. Kim DB. Cross chop: modified rotationless horizontal chop technique for weak zonules. J Cataract Refract Surg 2009; 35:1335– 1337 5. Braga-Mele R, Khan BU. Hydro-chop technique for soft lenses. J Cataract Refract Surg 2006; 32:18–20 6. Kim DY, Jang JH. Drill and chop: modified vertical chop technique for hard cataract. Ophthalmic Surg Lasers Imaging 2012; 43:169–172
7. Pandit RT. Combo-chop nuclear disassembly [letter]. J Cataract Refract Surg 2007; 33:2155
OTHER CITED MATERIAL A. Nagahara K, “Phaco Chop,” film presented at the ASCRS 3rd American–International Congress on Cataract, IOL and Refractive Surgery, Seattle, Washington, USA, May 1993
J CATARACT REFRACT SURG - VOL 42, OCTOBER 2016