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Trough and Crater Divide and Conquer Nucleofractis Techniques
Trough and Crater Divide and Conquer Nucleofractis Techniques HOWARD V. GIMBEL Gimbel Eye Centre, Calgary, Alberta, Canada
Seventy consecutive cataract surgeries performed by one surgeon were examined for phaco style. In-situ nucleofractis phacoemulsification was classified according to two broad styles: Trough and Crater Divide and Conquer. Variations of the nucleofractis techniques were described according to cataract density. Ultrasound times were measured. Keywords: Anterior capsule; Capsulectomy; Cataract; Continuous Curvilinear Capsulorhexis (CCC); Crater Divide and Conquer; Divide and Conquer; In-situ phacoemulsification; Intraocular lens; Nucleofractis; Posterior capsule; Trough Divide and Conquer. INTRODUCTION
Phacoemulsification, since its origin in the 1960s, has changed through the years and phaco techniques are still evolving. Besides the advantages of a smaller wound, phacoemulsification allows for the removal of even dense brunescent nuclei through Continuous Curvilinear Capsulorhexis (CCC) openings. In the early 1980s, as phacoemulsification was being applied to more and more dense nuclei, I developed in-situ nuclear fracturing techniques which added to the safety and efficiency of phacoemulsification [1]. With the preservation of an intact capsular bag using CCC, fixation and centration of the intraocular lens (lOL) is insured after safe and efficient in-the-bag phacoemulsification [2]. Because of its efficiency, I coined the term Divide and Conquer for these fracturing in-situ techniques and introduced them by way of a video in the September 1987 EIIC Meeting [1]. This term seemed appropriate because it is more efficient to emulsify a cataract after it has been mechanically divided into multiple sections using two instruments than to attempting to extract it through random sculpting and impaling techniques. Since the early 1980s I have been using nucleofractis techniques in soft to moderately dense nuclei [1]. In these cases I used the Trough Divide and Conquer technique [1]. As I began to apply in-the-bag phacoemulsification techniques to more and more dense nuclei, I developed a Correspondence to: Howard Gimbel, Gimbel Eye Centre, Suite 450,4935-40 Ave. NW, Calgary, AB, Canada, T3A 2Nl.
0955-3681/91/020123+04 $03.00/0 © 1991 Bailliere Tindall
technique called Crater Divide and Conquer nucleofractis for these very dense cataracts [1]. These two major categories of Divide and Conquer in-situ phacoemulsification, with subtle variations of each, allow me to use phacoemulsification in virtually 100% of my cases. We recently carried out a study of 70 consecutive cataract cases in regards to the frequency of each technique used. MATERIALS AND METHODS
In a prospective study 70 consecutive cataractllOL cases, performed by the author, were analysed for phacoemulsification styles during February 1990. Various timings of different sections of the surgery were recorded and these data sets were used to compile results. All data were entered in on-line medical records at the time of surgery. In addition to the patient's name and age, surgical procedures such as hydrodissection, capsulectomy type and phaco style were recorded, as were any intraoperative complications. Intraoperative timings were also recorded. The capsulectomy was timed from entry to exit of the cystotome in the anterior chamber. Entry and exit of the instrument from the anterior chamber also determined the start and end times for other time measurements. 'Phaco tip time' was the time that the phacoemulsifier tip was within the anterior chamber. 'Phaco power time' was the time that the emulsifier tip was actually active using ultrasound power. This value was obtained from the automatic instrument clock. Finally, total time that the phaco Eur J Implant Ref Surg, Vol 3, June 1991
Howard V. Gimbel
124
and irrigation/aspiration (VA) tips were in the anterior chamber were also measured and recorded. Note that whenever an instrument was removed briefly, the timer clock was set on pause. TROUGH DIVIDE AND CONQUER (TDC)
In the soft to moderately hard nuclear cataract densities, the Trough Divide and Conquer nucleofractis technique was used. This technique involved the making of a deep vertical trough in the nucleus with subsequent splitting of it by pushing to the right with the phaco tip and to the left with the cyclodialysis spatula (Fig. 1). The author is a righthanded surgeon. The phaco tip then impaled the
Fig. 3 Trough Divide and Conquer emulsification of nuclear quadrants in the centre of the pupil
efficient and safe emulsification (Fig. 3) [3]. In this technique the emulsification tip does not go under the capsule, but stays in the centre of the lens. If it does go under the capsule edge it is only in aspiration mode, or for a very short burst of ultrasound used to obtain a hold of the lens material. CRATER DIVIDE AND CONQUER (CDC)
left-hand section and a quadrant was fractured and emulsified (Fig. 2). Subsequently the right-hand segment was fractured by using the two-instrument technique and the remaining quadrants were brought into the central part of the capsular bag for
As lenses become more dense, the nucleofractis technique changes. In moderately hard to very hard nuclei, including brunescent cataracts, the Crater Divide and Conquer nucleofractis technique was employed. In this technique a deep central crater was made in the nucleus (Fig. 4). A trough is not used in these cases because it does not sufficiently weaken the lens nucleus enough to fracture easily and also the resulting segments are too large to manage safely. Therefore, a crater is cored deep enough to penetrate the posterior part of the nucleus. Once central sculpting and coring of the lens is
Fig. 2 Trough Divide and Conquer fracturing and emulsification of the first quadrant
Fig. 4 Crater Divide and Conquer involves making of a central crater
Fig. 1 Trough Divide and Conquer involves making a vertical trough with subsequent splitting of the nucleus
cur J Implant Ref Surg, Val 3, June 1991
125
Trough and Crater Divide and Conquer Nucleofractls Techniques
DISCUSSION
Table 1 shows the results of the Divide and Conquer Table 1 Divide and Conquer nucleofractis results Age CCC time n
% (years) SD
Too soft to crack 9 13 57.3 D & C nucleofractis 61 87 Trough Divide and Conquer 43 61 74.5 Crater Divide and Conquer 18 26 75.5
Fig. 5 Crater Divide and Conquer systematic multiple fracturing
accomplished, the nuclear rim is systematically divided (Fig. 5). However, rather than emulsifying each section immediately, the sections are left in place. This is the variation of the technique that I use in dense brunescent cataracts so that the fractured lens material continues to fill up the capsular bag and hold the nuclear pieces in place, in order to facilitate complete fracturing of the nuclear rim. Once this has been completed, each pie-shaped piece of the nuclear rim is brought to the centre of the capsule where phacoemulsification is safer (Fig. 6). The ultrasonic turbulence is still contained within the lens and absorbed by the lens and capsule for all except the last one or two fragments.
SD
0.2
9.4 0.9 5 .8 1.1
0.2 0.7
Nucleofractis study of styles. All of the 70 consecutive cataract/lOL cases were accomplished by phacoemulsification. Nine (13%) of these cases had nuclei too soft to crack. Divide and Conquer nucleofractis was used in the other 61 (87%) of the cases. The nuclei too soft to crack were found in the relatively younger patients with an average age of 57.3 years and a standard deviation of 11.8 years. The soft to moderately dense nuclei were found in patients with an average age of 74.5 years and a standard deviation of 9.4. In this group the Trough Divide and Conquer nucleofractis technique was used. In the moderately hard to hard nuclei, the Crater Divide and Conquer nucleofractis technique was used. The average age for this group was 75.5 years with a standard deviation of 5.8 years. Continuous Curvilinear Capsulorhexis (CCC) was used in all the cases and the capsulectomy times compared consistently in all the cases. The capsulectomy time averaged 0.9 min in the Trough Divide and Conquer group where the nuclei was soft to
Fig. 6 Crater Divide and Conquer emulsification of individual nuclear segments Eur J Implant Ref Surg, Vol 3, June 1991
(min)
11.8 1.0
Howard V. Gimbel
126
moderately hard. These cases are most ideal for performing CCC and phaco, for in the 'too soft to crack' group of the moderately hard nuclei group, there may be problems in carrying out CCC either because of positive vitreous pressure in younger patients, or because the capsule is too flaccid or poorly visualized in dense cataracts. Table 2 shows the efficiency of the Divide and Table 2 Divide and Conquer technique Soft Moderate No fracture TDC Phaco Power Time (mins) 1.5 2.1 SD 0.6 0.4 Range 1.4-4.2 0.5-2.0 Xfracture (mins) 0.3 SD 0.2 Phaco tip time (mins) 1.9 2.4 SD 0.4 0.4
Hard CDC 4.4 2.3 2.3-10.5 0.5 0.5 4.9 2.8
Conquer nucleofractis techniques and has a breakdown of the mean ultrasound time, the mean fracture time and the total time of the phaco tip in the anterior chamber for each of the three groups. The ultrasound time increased in parallel to the increase in the density of the nuclei. The range for the moderately dense nuclei using the TDC was 2.1 min as compared to 4.4 min in the hard nuclei using CDC. The range of ultrasound times, however, shows an overlap between the TDC and the CDC technique. As the surgeon becomes more experienced in judging the nuclear density, he or she will soon learn to apply TDC or CDC appropriately but will still notice an overlap of techniques. In other words, either technique may be appropriate in the transition group. The mean fracture time also increased with the
increase in the density of the nuclei. As the nuclei became more dense, the total time of the phaco tip in the anterior chamber also increased. The safety of the TDC or CDC Divide and Conquer nucleofractis technique is that the ultrasonic turbulence is always down within the lens and absorbed by the lens, and even though the surgeon may phaco for 10.5 min in a dense brunescent cataract, the corneal endothelium is not traumatized significantly. The interdependence of the Divide and Conquer techniques with CCC decreases the potential for intraoperative complications. No AC or PC tears were experienced in this study and all cases had PCIOLs placed in the bag. CONCLUSION
The Divide and Conquer nucleofractis techniques provide efficient and safe phacoemulsification of even dense nuclei and facilitate phacoemulsification through small pupils. They also more consistently preserve the anterior capsule rim intact for certain in-the-bag placement of soft and hard intraocular lenses, thus insuring long-lasting centration. REFERENCES HV Gimbel. Divide and conquer nucleofractis phacoemulsification. Development and variations. J. Cataract Refract. Surg., 1991; 17: 281-291. 2 HV Gimbel. Development, advantages and methods of the continuous circular capsulorhexis. J. Cataract Refract. Surg., 1990; 16: 31-37. 3 HV Gimbel. Phaco techniques-third generation. Ocular Surgery News, 1991; Feb 15: 52-55.
Eur J Implant Ref Surg, Vo/3, June 1991
Seventy consecutive cataract surgeries performed by one surgeon were examined for phaco style. In-situ nucleofractis phacoemulsification was classified according to two broad styles: Trough and Crater Divide and Conquer. Variations of the nucleofractis techniques were described according to cataract density. Ultrasound times were measured. Keywords: Anterior capsule; Capsulectomy; Cataract; Continuous Curvilinear Capsulorhexis (CCC); Crater Divide and Conquer; Divide and Conquer; In-situ phacoemulsification; Intraocular lens; Nucleofractis; Posterior capsule; Trough Divide and Conquer. INTRODUCTION
Phacoemulsification, since its origin in the 1960s, has changed through the years and phaco techniques are still evolving. Besides the advantages of a smaller wound, phacoemulsification allows for the removal of even dense brunescent nuclei through Continuous Curvilinear Capsulorhexis (CCC) openings. In the early 1980s, as phacoemulsification was being applied to more and more dense nuclei, I developed in-situ nuclear fracturing techniques which added to the safety and efficiency of phacoemulsification [1]. With the preservation of an intact capsular bag using CCC, fixation and centration of the intraocular lens (lOL) is insured after safe and efficient in-the-bag phacoemulsification [2]. Because of its efficiency, I coined the term Divide and Conquer for these fracturing in-situ techniques and introduced them by way of a video in the September 1987 EIIC Meeting [1]. This term seemed appropriate because it is more efficient to emulsify a cataract after it has been mechanically divided into multiple sections using two instruments than to attempting to extract it through random sculpting and impaling techniques. Since the early 1980s I have been using nucleofractis techniques in soft to moderately dense nuclei [1]. In these cases I used the Trough Divide and Conquer technique [1]. As I began to apply in-the-bag phacoemulsification techniques to more and more dense nuclei, I developed a Correspondence to: Howard Gimbel, Gimbel Eye Centre, Suite 450,4935-40 Ave. NW, Calgary, AB, Canada, T3A 2Nl.
0955-3681/91/020123+04 $03.00/0 © 1991 Bailliere Tindall
technique called Crater Divide and Conquer nucleofractis for these very dense cataracts [1]. These two major categories of Divide and Conquer in-situ phacoemulsification, with subtle variations of each, allow me to use phacoemulsification in virtually 100% of my cases. We recently carried out a study of 70 consecutive cataract cases in regards to the frequency of each technique used. MATERIALS AND METHODS
In a prospective study 70 consecutive cataractllOL cases, performed by the author, were analysed for phacoemulsification styles during February 1990. Various timings of different sections of the surgery were recorded and these data sets were used to compile results. All data were entered in on-line medical records at the time of surgery. In addition to the patient's name and age, surgical procedures such as hydrodissection, capsulectomy type and phaco style were recorded, as were any intraoperative complications. Intraoperative timings were also recorded. The capsulectomy was timed from entry to exit of the cystotome in the anterior chamber. Entry and exit of the instrument from the anterior chamber also determined the start and end times for other time measurements. 'Phaco tip time' was the time that the phacoemulsifier tip was within the anterior chamber. 'Phaco power time' was the time that the emulsifier tip was actually active using ultrasound power. This value was obtained from the automatic instrument clock. Finally, total time that the phaco Eur J Implant Ref Surg, Vol 3, June 1991
Howard V. Gimbel
124
and irrigation/aspiration (VA) tips were in the anterior chamber were also measured and recorded. Note that whenever an instrument was removed briefly, the timer clock was set on pause. TROUGH DIVIDE AND CONQUER (TDC)
In the soft to moderately hard nuclear cataract densities, the Trough Divide and Conquer nucleofractis technique was used. This technique involved the making of a deep vertical trough in the nucleus with subsequent splitting of it by pushing to the right with the phaco tip and to the left with the cyclodialysis spatula (Fig. 1). The author is a righthanded surgeon. The phaco tip then impaled the
Fig. 3 Trough Divide and Conquer emulsification of nuclear quadrants in the centre of the pupil
efficient and safe emulsification (Fig. 3) [3]. In this technique the emulsification tip does not go under the capsule, but stays in the centre of the lens. If it does go under the capsule edge it is only in aspiration mode, or for a very short burst of ultrasound used to obtain a hold of the lens material. CRATER DIVIDE AND CONQUER (CDC)
left-hand section and a quadrant was fractured and emulsified (Fig. 2). Subsequently the right-hand segment was fractured by using the two-instrument technique and the remaining quadrants were brought into the central part of the capsular bag for
As lenses become more dense, the nucleofractis technique changes. In moderately hard to very hard nuclei, including brunescent cataracts, the Crater Divide and Conquer nucleofractis technique was employed. In this technique a deep central crater was made in the nucleus (Fig. 4). A trough is not used in these cases because it does not sufficiently weaken the lens nucleus enough to fracture easily and also the resulting segments are too large to manage safely. Therefore, a crater is cored deep enough to penetrate the posterior part of the nucleus. Once central sculpting and coring of the lens is
Fig. 2 Trough Divide and Conquer fracturing and emulsification of the first quadrant
Fig. 4 Crater Divide and Conquer involves making of a central crater
Fig. 1 Trough Divide and Conquer involves making a vertical trough with subsequent splitting of the nucleus
cur J Implant Ref Surg, Val 3, June 1991
125
Trough and Crater Divide and Conquer Nucleofractls Techniques
DISCUSSION
Table 1 shows the results of the Divide and Conquer Table 1 Divide and Conquer nucleofractis results Age CCC time n
% (years) SD
Too soft to crack 9 13 57.3 D & C nucleofractis 61 87 Trough Divide and Conquer 43 61 74.5 Crater Divide and Conquer 18 26 75.5
Fig. 5 Crater Divide and Conquer systematic multiple fracturing
accomplished, the nuclear rim is systematically divided (Fig. 5). However, rather than emulsifying each section immediately, the sections are left in place. This is the variation of the technique that I use in dense brunescent cataracts so that the fractured lens material continues to fill up the capsular bag and hold the nuclear pieces in place, in order to facilitate complete fracturing of the nuclear rim. Once this has been completed, each pie-shaped piece of the nuclear rim is brought to the centre of the capsule where phacoemulsification is safer (Fig. 6). The ultrasonic turbulence is still contained within the lens and absorbed by the lens and capsule for all except the last one or two fragments.
SD
0.2
9.4 0.9 5 .8 1.1
0.2 0.7
Nucleofractis study of styles. All of the 70 consecutive cataract/lOL cases were accomplished by phacoemulsification. Nine (13%) of these cases had nuclei too soft to crack. Divide and Conquer nucleofractis was used in the other 61 (87%) of the cases. The nuclei too soft to crack were found in the relatively younger patients with an average age of 57.3 years and a standard deviation of 11.8 years. The soft to moderately dense nuclei were found in patients with an average age of 74.5 years and a standard deviation of 9.4. In this group the Trough Divide and Conquer nucleofractis technique was used. In the moderately hard to hard nuclei, the Crater Divide and Conquer nucleofractis technique was used. The average age for this group was 75.5 years with a standard deviation of 5.8 years. Continuous Curvilinear Capsulorhexis (CCC) was used in all the cases and the capsulectomy times compared consistently in all the cases. The capsulectomy time averaged 0.9 min in the Trough Divide and Conquer group where the nuclei was soft to
Fig. 6 Crater Divide and Conquer emulsification of individual nuclear segments Eur J Implant Ref Surg, Vol 3, June 1991
(min)
11.8 1.0
Howard V. Gimbel
126
moderately hard. These cases are most ideal for performing CCC and phaco, for in the 'too soft to crack' group of the moderately hard nuclei group, there may be problems in carrying out CCC either because of positive vitreous pressure in younger patients, or because the capsule is too flaccid or poorly visualized in dense cataracts. Table 2 shows the efficiency of the Divide and Table 2 Divide and Conquer technique Soft Moderate No fracture TDC Phaco Power Time (mins) 1.5 2.1 SD 0.6 0.4 Range 1.4-4.2 0.5-2.0 Xfracture (mins) 0.3 SD 0.2 Phaco tip time (mins) 1.9 2.4 SD 0.4 0.4
Hard CDC 4.4 2.3 2.3-10.5 0.5 0.5 4.9 2.8
Conquer nucleofractis techniques and has a breakdown of the mean ultrasound time, the mean fracture time and the total time of the phaco tip in the anterior chamber for each of the three groups. The ultrasound time increased in parallel to the increase in the density of the nuclei. The range for the moderately dense nuclei using the TDC was 2.1 min as compared to 4.4 min in the hard nuclei using CDC. The range of ultrasound times, however, shows an overlap between the TDC and the CDC technique. As the surgeon becomes more experienced in judging the nuclear density, he or she will soon learn to apply TDC or CDC appropriately but will still notice an overlap of techniques. In other words, either technique may be appropriate in the transition group. The mean fracture time also increased with the
increase in the density of the nuclei. As the nuclei became more dense, the total time of the phaco tip in the anterior chamber also increased. The safety of the TDC or CDC Divide and Conquer nucleofractis technique is that the ultrasonic turbulence is always down within the lens and absorbed by the lens, and even though the surgeon may phaco for 10.5 min in a dense brunescent cataract, the corneal endothelium is not traumatized significantly. The interdependence of the Divide and Conquer techniques with CCC decreases the potential for intraoperative complications. No AC or PC tears were experienced in this study and all cases had PCIOLs placed in the bag. CONCLUSION
The Divide and Conquer nucleofractis techniques provide efficient and safe phacoemulsification of even dense nuclei and facilitate phacoemulsification through small pupils. They also more consistently preserve the anterior capsule rim intact for certain in-the-bag placement of soft and hard intraocular lenses, thus insuring long-lasting centration. REFERENCES HV Gimbel. Divide and conquer nucleofractis phacoemulsification. Development and variations. J. Cataract Refract. Surg., 1991; 17: 281-291. 2 HV Gimbel. Development, advantages and methods of the continuous circular capsulorhexis. J. Cataract Refract. Surg., 1990; 16: 31-37. 3 HV Gimbel. Phaco techniques-third generation. Ocular Surgery News, 1991; Feb 15: 52-55.
Eur J Implant Ref Surg, Vo/3, June 1991