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Blunt, bent needle for continuous curvilinear capsulorhexis
techniques Blunt, bent needle for continuous curvilinear capsulorhexis Jorg H. Krumeich, MD, Jan Daniel, MD ABSTRACT We describe an anterior continuous curvilinear capsulorhexis (CCC) technique that uses a dull needle. The needle's blunt tip prevents inadvertent tearing of the anterior capsule, and its rough surface allows the surgeon to transmit a power vector of different amplitude and direction to the edge of the capsulorhexis to continue the tear as desired. For biomechanical reasons, we prefer an arcade-shaped CCC because this configuration provides a greater circumference than a circular CCC. The blunt needle allows one to perform a single-step capsulorhexis in a safe and controlled manner and reduces surgical time. Even in cases of white and liquefied cortex, the dull needle has proved a useful, safe tool. J Cataract Refract Surg 1998; 24:1180-1183
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xtracapsular cataract extraction allows implantation of an artificial lens in the capsular bag. To keep the capsular bag intact, several methods of opening the anterior capsule have been introduced. 1- 10 Cataract surgeons agree that an anterior continuous curvilinear capsulorhexis (CCC) should be the goal of every anterior capsule opening. Inadvertent extension of the capsulorhexis toward the periphery must be prevented because this might jeopardize implanting the intraocular lens (IOL) in the bag. 1•2•9 Successful performance of an anterior CCC can result in quick, uneventful surgery. If the continuity of the capsulorhexis border is not preserved, however, several typical complications may ensue. Among the
From the Eye Dtpartmmt, Martin-Luther-Hospital, Bochum, Germany. Neither of the authors has a proprietary or commercial interest in the device described.
instruments customarily used are a sharp capsulorhexis needle, Fine forceps, and capsulotome. The number of instruments and techniques indicates that all the techniques may have some shortcomings. From our point of view, the optimal instrument should have a small diameter to prevent the anterior chamber from collapsing while the CCC is performed. The instrument should provide immediate irrigation in case the capsule has to be visualized better or the anterior chamber deepened. The capsulorhexis instrument should facilitate the primary central opening of the capsule and continuation of the tear. We have found that a blunt, rough needle approach meets these requirements. Providing the advantages of the original sharp needle, the modified needle tip allows continuation of the tear toward the desired direction without risking a peripheral capsule perforation. The blunt rough capsulorhexis is connected to the irrigation port of the phacoemulsification machine and serves as a single instrument for the procedure.
Volkhard Lau provided the illustrations; Fa. Geuder, Germany. modified the needle to our specifications. &print requests to ]org H. Krumeich, MD, Head ofEye Department, Martin-Luther-Hospital Bochum, Propst-Hellmich-Promenade 28, 44866 Bochum, Germany. 1180
Technique The dull capsulorhexis needle is derived from a standard sharp cannula for intravenous injection; it has
J CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
TECHNIQUES: KRUMEICH
an inner opening of 0.42 mm and an outer diameter of 0.60 mm. The tip of the cannula is bent downward with a needle holder to an angle of 125 degrees. To increase the tip surface, the tip is blunted by running it over a fine tool file (grain size 10 J..Lm) for 50 mm while pressing down with a power of approximately 50 mN. The blunting process results in an enlarged plane tip surface of approximately 0.04 mm2 • In a second step, the tip of the cannula is roughened by means of a diamond rasp (grain size 15 J..Lm). The needle tip is manually scraped one time over a distance of 50 mm, while being pressed down with a power of 250 mN. Following this, the needle tip is carefully cleaned using a brush to remove the remaining metal particles. The needle is mounted on a handpiece connected to the irrigation of the phaco machine. After the anterior chamber is opened, it is filled with a viscoelastic substance. A clear corneal or scleral tunnel incision can be used to introduce the needle into the anterior chamber. The small outer diameter of the needle prevents the chamber from collapsing while the needle enters and during subsequent surgical manipulation, which frequently occurs when a forceps (e.g., Paufique) is used. To facilitate control of the instrument, the second hand guides the needle with a forceps. The tip of the needle is set slightly beneath the center of the intended capsule opening. The anterior capsule is indented firmly until the capsule is perforated
Figure 1. (Krumeich) The blunt capsulorhexis needle is inserted into the anterior chamber. The primary tear is achieved centrally by a slight indentation with the needle tip. The arrow heads indicate immanent power vector (--i>); transmitted power vector(-); resulting tear(-+).
(Figure 1). The needle is then placed centrally to the edge of the tear to create an arch. (The configuration of the CCC will be a small arcade.) The needle is then lifted slightly and again placed beside and central to the edge of the tear (Figure 2). The procedure is repeated until a 360 degree tear is created. If desired by the surgeon, this can be achieved with 6 to 10 arches (Figure 3).
Figure 2. (Krumeich) The needle tip is slightly pressed onto the capsule. The roughness of the tip allows it to transmit a vector of defined amplitude and direction to the tear. The capsule tears according to the resulting vector. The different arrow heads indicate immanent power vector (--i>); transmitted power vector(-); resulting tear(-+).
J CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
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TECHNIQUES: KRUMEICH
Figure 3. (Krumeich) A complete anterior CCC is achieved. The arcade configuration is used to increase the circumference of the capsule opening while maintaining a mean diameter of 5.0 to 6.0 mm (according to the optics).
Discussion Various forceps for CCC have been introduced. 1-4,G However, the forceps approach has shortcomings. The forceps primarily serves as a second instrument that must be introduced into the anterior chamber; a needle is used for the initial capsule opening. If the anterior chamber collapses, the procedure must be stopped, the forceps removed, and a third instrument introduced to reinject a viscoelastic substance. Because it does not have an infusion port, the forceps does not enable one to visualize the tear and anterior capsule. If a diathermy capsulotome is used, the capsule edge may shrink from the thermal effects and lose elasticity. Furthermore, with this instrument, a second instrument is frequently necessary to connect the multiple tiny capsule perforations to achieve a continuous opening. As with the forceps, the capsulotome does not have an infusion capability to reconstruct the anterior chamber and restore visualization of the tear. In contrast to forceps, the sharp needle has a small diameter and the option to use infusion during any phase of the CCC. However, sharp needles cannot transmit enough friction between tip and tissue to stop an outward drifting tear. The disadvantages of these instruments led us to think about using a rough capsulorhexis needle. This device allows one to exert a defined power in any 1182
direction. Traction may be transmitted via the top of the needle directly to the edge of the capsulorhexis. Roughing the blunt tip of the needle appeared to be the crucial element in this technique. When we were developing it, we had to find the optimal combination of an enlarged tip surface and roughness. If the tip surface is too large, one may not be able to perform the primary opening of the tear. If the needle tip is too small, undesired additional tears may arise, as occurs with sharp needles. The appropriate degree of roughness must be achieved or the power cannot be transferred to the capsule; the needle tip would glide over the capsule. Through several clinical trials, we found a working combination of tip surface and roughness. With this technique the surgeon is able to force the tear in the direction desired. Unexpected additional tears can be avoided. As shown in the literature, most surgeons attempt a perfect circular opening in the anterior capsule. 1- 3•1°For biomechanical reasons, we suggest changing the configuration of the anterior opening to that of an arcade. While maintaining the same mean diameter of the central opening, an arcade-shaped capsulorhexis provides a much greater overall length. Based on the radii and number of arches, the CCC circumference may increase by 140 to 180% of a simple circular capsulorhexis opening. Such an extended circumference may be able to withstand higher powers during surgical manipulation or implantation of the lens. This capsulorhexis configuration can be accomplished routinely with the blunt tip. In summary, we believe that the blunt rough capsulorhexis needle technique, which we have used in more than 2000 cataract procedures, allows a more controlled performance of the anterior capsule tear. The larger circumference of an arcade-shaped capsulorhexis provides a greater safety margin for intraoperative maneuvers.
References 1. Neuhann T. Theorie und Operationstechnik der Kapsulo-
rhexis. Klin Monatsbl Augenheilkd 1987; 190:542-545 2. Gimbel HV, Neuhann T. Development, advantages, and
methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg 1990; 16:31-37 3. Gimbel HV, Neuhann T. Continuous curvilinear capsu-
] CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
TECHNIQUES: KRUMEICH
lorhexis technique (letter). J Cataract Refract Surg 1991; 17:110-111 4. Blumenthal M, Assia E, Moisseiev J. Manual ECCE, the present state of the art. Asia-Pacific J Ophthalmol1995; 7(4):21-24 5. Wilson ME, Bluestein EC, Wang X-H, Apple OJ. Comparison of mechanized anterior capsulectomy and manual continuous capsulorhexis in pediatric eyes. J Cataract Refract Surg 1994; 20:602-606 6. Sergienko NM. Forceps for capsulorhexis. J Cataract Refract Surg 1996; 22:1406-1407
7. Assia EI, Apple OJ, Barden A, et al. An experimental study comparing various anterior capsulectomy techniques. Arch Ophthalmol 1991; 109:642-647 8. Gassmann F, Schimmelpfennig B, Kloti R. Anterior capsulotomy by means of bipolar radio-frequency endodiathermy. J Cataract Refract Surg 1988; 14:673-676 9. Gimbel HV, Kaye GB. Forceps-puncture continuous curvilinear capsulorhexis. J Cataract Refract Surg 1997; 23:473-475 10. Vasavada A, Desai J, Singh R. Enlarging the capsularhexis. J Cataract Refract Surg 1997; 23:329-331
] CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
1183
E
xtracapsular cataract extraction allows implantation of an artificial lens in the capsular bag. To keep the capsular bag intact, several methods of opening the anterior capsule have been introduced. 1- 10 Cataract surgeons agree that an anterior continuous curvilinear capsulorhexis (CCC) should be the goal of every anterior capsule opening. Inadvertent extension of the capsulorhexis toward the periphery must be prevented because this might jeopardize implanting the intraocular lens (IOL) in the bag. 1•2•9 Successful performance of an anterior CCC can result in quick, uneventful surgery. If the continuity of the capsulorhexis border is not preserved, however, several typical complications may ensue. Among the
From the Eye Dtpartmmt, Martin-Luther-Hospital, Bochum, Germany. Neither of the authors has a proprietary or commercial interest in the device described.
instruments customarily used are a sharp capsulorhexis needle, Fine forceps, and capsulotome. The number of instruments and techniques indicates that all the techniques may have some shortcomings. From our point of view, the optimal instrument should have a small diameter to prevent the anterior chamber from collapsing while the CCC is performed. The instrument should provide immediate irrigation in case the capsule has to be visualized better or the anterior chamber deepened. The capsulorhexis instrument should facilitate the primary central opening of the capsule and continuation of the tear. We have found that a blunt, rough needle approach meets these requirements. Providing the advantages of the original sharp needle, the modified needle tip allows continuation of the tear toward the desired direction without risking a peripheral capsule perforation. The blunt rough capsulorhexis is connected to the irrigation port of the phacoemulsification machine and serves as a single instrument for the procedure.
Volkhard Lau provided the illustrations; Fa. Geuder, Germany. modified the needle to our specifications. &print requests to ]org H. Krumeich, MD, Head ofEye Department, Martin-Luther-Hospital Bochum, Propst-Hellmich-Promenade 28, 44866 Bochum, Germany. 1180
Technique The dull capsulorhexis needle is derived from a standard sharp cannula for intravenous injection; it has
J CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
TECHNIQUES: KRUMEICH
an inner opening of 0.42 mm and an outer diameter of 0.60 mm. The tip of the cannula is bent downward with a needle holder to an angle of 125 degrees. To increase the tip surface, the tip is blunted by running it over a fine tool file (grain size 10 J..Lm) for 50 mm while pressing down with a power of approximately 50 mN. The blunting process results in an enlarged plane tip surface of approximately 0.04 mm2 • In a second step, the tip of the cannula is roughened by means of a diamond rasp (grain size 15 J..Lm). The needle tip is manually scraped one time over a distance of 50 mm, while being pressed down with a power of 250 mN. Following this, the needle tip is carefully cleaned using a brush to remove the remaining metal particles. The needle is mounted on a handpiece connected to the irrigation of the phaco machine. After the anterior chamber is opened, it is filled with a viscoelastic substance. A clear corneal or scleral tunnel incision can be used to introduce the needle into the anterior chamber. The small outer diameter of the needle prevents the chamber from collapsing while the needle enters and during subsequent surgical manipulation, which frequently occurs when a forceps (e.g., Paufique) is used. To facilitate control of the instrument, the second hand guides the needle with a forceps. The tip of the needle is set slightly beneath the center of the intended capsule opening. The anterior capsule is indented firmly until the capsule is perforated
Figure 1. (Krumeich) The blunt capsulorhexis needle is inserted into the anterior chamber. The primary tear is achieved centrally by a slight indentation with the needle tip. The arrow heads indicate immanent power vector (--i>); transmitted power vector(-); resulting tear(-+).
(Figure 1). The needle is then placed centrally to the edge of the tear to create an arch. (The configuration of the CCC will be a small arcade.) The needle is then lifted slightly and again placed beside and central to the edge of the tear (Figure 2). The procedure is repeated until a 360 degree tear is created. If desired by the surgeon, this can be achieved with 6 to 10 arches (Figure 3).
Figure 2. (Krumeich) The needle tip is slightly pressed onto the capsule. The roughness of the tip allows it to transmit a vector of defined amplitude and direction to the tear. The capsule tears according to the resulting vector. The different arrow heads indicate immanent power vector (--i>); transmitted power vector(-); resulting tear(-+).
J CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
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TECHNIQUES: KRUMEICH
Figure 3. (Krumeich) A complete anterior CCC is achieved. The arcade configuration is used to increase the circumference of the capsule opening while maintaining a mean diameter of 5.0 to 6.0 mm (according to the optics).
Discussion Various forceps for CCC have been introduced. 1-4,G However, the forceps approach has shortcomings. The forceps primarily serves as a second instrument that must be introduced into the anterior chamber; a needle is used for the initial capsule opening. If the anterior chamber collapses, the procedure must be stopped, the forceps removed, and a third instrument introduced to reinject a viscoelastic substance. Because it does not have an infusion port, the forceps does not enable one to visualize the tear and anterior capsule. If a diathermy capsulotome is used, the capsule edge may shrink from the thermal effects and lose elasticity. Furthermore, with this instrument, a second instrument is frequently necessary to connect the multiple tiny capsule perforations to achieve a continuous opening. As with the forceps, the capsulotome does not have an infusion capability to reconstruct the anterior chamber and restore visualization of the tear. In contrast to forceps, the sharp needle has a small diameter and the option to use infusion during any phase of the CCC. However, sharp needles cannot transmit enough friction between tip and tissue to stop an outward drifting tear. The disadvantages of these instruments led us to think about using a rough capsulorhexis needle. This device allows one to exert a defined power in any 1182
direction. Traction may be transmitted via the top of the needle directly to the edge of the capsulorhexis. Roughing the blunt tip of the needle appeared to be the crucial element in this technique. When we were developing it, we had to find the optimal combination of an enlarged tip surface and roughness. If the tip surface is too large, one may not be able to perform the primary opening of the tear. If the needle tip is too small, undesired additional tears may arise, as occurs with sharp needles. The appropriate degree of roughness must be achieved or the power cannot be transferred to the capsule; the needle tip would glide over the capsule. Through several clinical trials, we found a working combination of tip surface and roughness. With this technique the surgeon is able to force the tear in the direction desired. Unexpected additional tears can be avoided. As shown in the literature, most surgeons attempt a perfect circular opening in the anterior capsule. 1- 3•1°For biomechanical reasons, we suggest changing the configuration of the anterior opening to that of an arcade. While maintaining the same mean diameter of the central opening, an arcade-shaped capsulorhexis provides a much greater overall length. Based on the radii and number of arches, the CCC circumference may increase by 140 to 180% of a simple circular capsulorhexis opening. Such an extended circumference may be able to withstand higher powers during surgical manipulation or implantation of the lens. This capsulorhexis configuration can be accomplished routinely with the blunt tip. In summary, we believe that the blunt rough capsulorhexis needle technique, which we have used in more than 2000 cataract procedures, allows a more controlled performance of the anterior capsule tear. The larger circumference of an arcade-shaped capsulorhexis provides a greater safety margin for intraoperative maneuvers.
References 1. Neuhann T. Theorie und Operationstechnik der Kapsulo-
rhexis. Klin Monatsbl Augenheilkd 1987; 190:542-545 2. Gimbel HV, Neuhann T. Development, advantages, and
methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg 1990; 16:31-37 3. Gimbel HV, Neuhann T. Continuous curvilinear capsu-
] CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
TECHNIQUES: KRUMEICH
lorhexis technique (letter). J Cataract Refract Surg 1991; 17:110-111 4. Blumenthal M, Assia E, Moisseiev J. Manual ECCE, the present state of the art. Asia-Pacific J Ophthalmol1995; 7(4):21-24 5. Wilson ME, Bluestein EC, Wang X-H, Apple OJ. Comparison of mechanized anterior capsulectomy and manual continuous capsulorhexis in pediatric eyes. J Cataract Refract Surg 1994; 20:602-606 6. Sergienko NM. Forceps for capsulorhexis. J Cataract Refract Surg 1996; 22:1406-1407
7. Assia EI, Apple OJ, Barden A, et al. An experimental study comparing various anterior capsulectomy techniques. Arch Ophthalmol 1991; 109:642-647 8. Gassmann F, Schimmelpfennig B, Kloti R. Anterior capsulotomy by means of bipolar radio-frequency endodiathermy. J Cataract Refract Surg 1988; 14:673-676 9. Gimbel HV, Kaye GB. Forceps-puncture continuous curvilinear capsulorhexis. J Cataract Refract Surg 1997; 23:473-475 10. Vasavada A, Desai J, Singh R. Enlarging the capsularhexis. J Cataract Refract Surg 1997; 23:329-331
] CATARACT REFRACT SURG-VOL 24, SEPTEMBER 1998
1183