|Year : 2016 | Volume
| Issue : 3 | Page : 627-631
Divide and conquer versus chopping in phacoemulsification: study of the operation events and early results
Hassan G El-Din Farahat1, Nermin M Badawy1, Faried M Wagdy Faried1, Yousef H. M. Ibrahim Mansour2
1 Department of Ophthalmology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Ophthalmology, Mansoura Ophthalmic Hospital, Mansoura, Egypt
|Date of Submission||12-Jul-2015|
|Date of Acceptance||01-Oct-2015|
|Date of Web Publication||23-Jan-2017|
Yousef H. M. Ibrahim Mansour
Department of Ophthalmology, Mansoura Ophthalmic Hospital, Mansoura
Source of Support: None, Conflict of Interest: None
The aim of the study is to evaluate the efficacy and safety of the divide-and-conquer technique versus chopping technique in phacoemulsification.
Kelman in 1967 introduced ultrasonic phacoemulsification for cataract removal, aiming to find a safer and more effective way of removing the lens. At present, phacoemulsification is the procedure of choice for cataract extraction for most ophthalmologists.
Materials and methods
This prospective study included 30 eyes of 30 patients attending the outpatient clinic of Menoufia Ophthalmic Department. Patients aged 40-60 years old with senile cataract nuclear grades from 2 to 4 underwent detailed history taking, full ophthalmic examination, A-B scan ultrasonography, corneal pachymetry and endothelial cell density measurements, and nuclear grading. All patients were operated by the same surgeon using Geuder megatron s3 machine.
There was statistically significant endothelial cell loss (ECL) following all studied techniques 3 months postoperatively (12.4 and 10.5% in groups I and II, respectively). There was no significant difference between all studied groups. The nuclear grade and absolute phaco time had positive correlation with higher ECL, whereas age, sex, and axial length did not affect ECL. A significant increase in the central corneal thickness (CCT) was observed at the immediate postoperative week among the two studied groups (14 and 10.5%, respectively). There was no statistically significant difference between the two groups. The postoperative CCT pachymetry values were returned to near preoperative values at 3 months postoperatively.
Significant and equal ECLs occur after the two studied techniques. Absolute phaco time and nuclear grade have a positive correlation with higher ECL. Age, sex, and axial length do not affect ECL. CCT increases significantly and equally postoperatively following the two techniques.
Keywords: absolute phaco time, divide and conquer, horizontal chopping, phacoemulsification, specular microscopy
|How to cite this article:|
El-Din Farahat HG, Badawy NM, Wagdy Faried FM, Ibrahim Mansour YH. Divide and conquer versus chopping in phacoemulsification: study of the operation events and early results. Menoufia Med J 2016;29:627-31
|How to cite this URL:|
El-Din Farahat HG, Badawy NM, Wagdy Faried FM, Ibrahim Mansour YH. Divide and conquer versus chopping in phacoemulsification: study of the operation events and early results. Menoufia Med J [serial online] 2016 [cited 2020 Apr 3];29:627-31. Available from: http://www.mmj.eg.net/text.asp?2016/29/3/627/198744
| Introduction|| |
Kelman in 1967 introduced ultrasonic phacoemulsification for cataract removal aiming to find a safer and more effective way of removing the lens. Phacoemulsification nowadays is the procedure of choice for cataract extraction for most ophthalmologists.
Divide-and-conquer technique, described by Gimbel, was the first nucleofractis cracking technique developed , . It provided safer surgery with less endothelial cell loss (ECL)  .
Koch and Katzen  modified the Nagahara technique because they encountered difficulty in mobilizing the nuclear fragments. They created a central groove or central crater to provide a space that facilitates the chopping procedure and removal of nuclear pieces. Controversy of endothelial cell damage after different phacoemulsification techniques has been reported as the cause of carrying out this study.
| Materials and methods|| |
All patients were operated by the same surgeon using Geuder megatron s3 machine (GEUDER AG, Heidelberg, Germany). Patients were randomly assigned to one of the two groups.
Group I (included 15 eyes): In this group phacoemulsification was performed using the divide-and-conquer technique.
Group II (included 15 eyes): In this group phacoemulsification was performed using the horizontal chopping technique
Nuclear fracture techniques
Nuclear fracturing technique was different for each group as follows.
- Group 1 (divide and conquer)
In the divide-and-conquer group, two memory programs were used
Phaco 1 was used for sculpting [maximum 70% ultrasound (US) power; vacuum, 20 mmHg; flow rate, 20-25 ml/min; and bottle height, 70-80 cm]. Phaco 2 was used for quadrant removal (maximum 50% pulsed mode US power; maximum vacuum, 350 mmHg; flow rate, 25-30 ml/min; and bottle height, 90-110 cm)
- Group 2 (horizontal chopping)
- The phaco 1 program was excluded and only the pulse-mode program, phaco 2, was used
- After the superficial cortex and epinucleus were aspirated, the phaco tip was buried in the center of the endonucleus at a high vacuum setting (350 mmHg). Next, the Nagahara phaco chopper was brought through the side-port incision, and the equator of endonucleus was engaged by the chopper under the capsulorhexis. The chopper was moved toward the phaco probe to initiate nuclear cracking. Both instruments were moved in opposite directions, dividing the nucleus into halves. The nucleus was then rotated through 90°, the phaco tip was impaled in the inferior hemisection of the nucleus, and the chopper was used to break this half into two smaller fragments, which were then emulsified. The procedure was repeated on the superior nucleus.
The following were reported during surgery.
- The total phaco time (s)
- The mean phaco power (%)
- Total phaco energy (the absolute phaco time, APT) was calculated by multiplying the phaco time (s) by the mean phaco power (%).
Operative complication such as posterior capsule rupture or iris trauma was also reported.
| Results|| |
Absolute phaco time
Study of the US time consumed during the operation indicated by APT [US energy (%) × US duration (s)] for the two groups is shown in [Table 1]. There was a statistically significant difference between the two groups (P < 0.001).
Endothelial cell count and endothelial cell loss
All groups had a significant decrease in endothelial cell counts at 1 week and 3 months postoperatively. [Table 2] and [Figure 1] revealed the means of endothelial cell densities preoperatively and during the follow-up period. Means of ECL postoperatively are also included in [Table 2] and [Figure 1].
|Table 2 Comparison between preoperative and postoperative endothelial cell counts and postoperative ECL in the studied groups |
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|Figure 1: Comparison between preoperative and postoperative mean endothelial cell counts and postoperative endothelial cell loss in the studied groups.|
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Central corneal thickness
The course of central corneal thickness (CCT) changes among the studied groups during postoperative follow-up period was illustrated. All groups showed a significant increase in CCT.
[Table 3] and [Figure 2] compare postoperative means of CCT with preoperative values in the studied groups. There was a significant difference between preoperative CCT and postoperative CCT at 1 week postoperatively in all groups. There was no significant difference between preoperative CCT and postoperative CCT at 3 months in all studied groups.
|Table 3 Comparison between preoperative and postoperative CCT during the follow - up period in the studied groups |
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|Figure 2: Comparison between preoperative and postoperative central corneal thickness during the follow-up period in the studied groups.|
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The amount and rates of increased CCT during the postoperative follow-up period, at 1 week and 3 months, among the studied groups are shown in [Table 4]. There was no significant difference seen between the two groups.
|Table 4 Comparison between postoperative increased rates of CCT among studied groups during the follow - up period |
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According to LOCS III classification system, nuclear firmness in this study was classified into three grades: grade 2, grade 3, and grade 4. Most cases were of grade 3 (moderate nuclear firmness). [Table 5] represents the detailed distribution of nuclear grade among the two groups.
| Discussion|| |
In the present study, the mean ECL after the divide-and-conquer technique at 3 months postoperatively was 12.4. This result is comparable to that of O'Brien et al.  (11.6%). Storr-Paulsen et al.  reported an ECL less than that of the present study (5%), whereas Al-Sharkawy  reported a higher ECL (15.20%).
ECL among the horizontal-chop group in the present study was 10.5%. It was much higher than that of Storr-Paulsen et al.  : 6.3%. In contrast to these results, Park et al.  reported much higher ECL 3 months postoperatively following horizontal-chop technique (16.3%). This discrepancy of results may be explained by the variation in surgeon's experiences and differences in the phaco machines and instruments used.
In the present study, there was a significant postoperative ECL among all studied groups. Comparison between these groups showed no significant statistical difference regarding postoperative ECL.
Storr-Paulsen et al.  compared ECL following divide-and-conquer versus horizontal-chop techniques.
Their findings were similar to the present study, as there was no significant difference in postoperative ECL after 3 months. Contrary to this, Pirazzoli et al.  reported a significant lower ECL following horizontal-chop technique. Other investigators, Wong et al.  , showed that US energy use was significantly less in the horizontal-chop technique than that of divide-and-conquer technique, but endothelial cell damage was not evaluated in their studies.
In the present study, the total US consumption (APT) in the divide-and-conquer group was 48.47. Wong et al.  reported higher APT means in two studies: a mean of 58.8 in a pilot study and 50.4 in a prospective study. The studies by Can et al.  and Storr-Paulsen et al.  showed lower APT means: 14.9 and 12.79, respectively.
The mean APT following phaco chop technique in the present study was 22.57. This is comparable to that reported by Can et al.  . Higher means were documented by Vajpayee et al.  (28 s). Some studies reported much lower APT after phaco chop technique: less than 10 in the study by Suzuki et al.  and 3.98 in the study by Storr-Paulsen et al.  . The discrepancy between the result of the present study and other studies can be attributed to variations of surgeons experiences and using different phacomachines.
Wong et al.  revealed that horizontal-chop technique involved a significant shorter phaco time and lower absolute phaco power than the divide-and-conquer technique, leading to less ECL. They postulated that less total energy leads to less endothelial cell damage. This hypothesis was confirmed by O'Brien et al.  , whereas the present study and the study by Storr-Paulsen et al.  showed that there was no positive correlation between the total US energy and ECL.
Measuring the difference in pachymetry at the first postoperative day is a useful way to assess the effects on the corneal endothelium exerted by the phacoemulsification procedure. The increase in CCT seen on the first postoperative day is strongly correlated with the corneal ECL at 3 months postoperatively  . In the present study, there was a significant increase in CCT at the immediate postoperative day. There was no significant difference between the two studied techniques.
Rates of increased CCT postoperatively in the present study are parallel to that reported by Lundberg et al.  and Park al.  . Higher rates were reported by others: Abo El-Khir et al.  and Can et al.  . The time interval of corneal recovery and returning to the preoperative pachymetry values was different in different studies, and it may be attributed to the different types of pachymetry devices used in measuring the CCT. In the present study, the preoperative pachymetry values were resumed at 3 months postoperatively. Can et al.  reported a shorter time interval (10-14 days).
Similar to the current study, Vajpayee et al.  , Storr-Paulsen et al.  , and Park et al.  did not find a significant difference between the studied phaco techniques regarding the increase of CCT.
Transient postoperative corneal edema is sometimes noted after phacoemulsification surgery  , indicating affection of the corneal endothelial pump function  . Results of the study by Lundberg et al.  indicated that clinically significant postoperative corneal edema was strongly associated with a clinically significant corneal ECL. The incidence of postoperative corneal edema in the present study was 30 and 20% in the divide-and-conquer and horizontal-chop groups, respectively. A significant difference was found in advantage of the horizontal-chop technique.
Phacoemulsification technique has the advantage of early visual rehabilitation after cataract surgery, and this is mainly attributed to the small incision size used. However, phacoemulsification is an expensive technique; hence, it is not an affordable technique in the developing countries with very low income. Manual small incision cataract surgery with its sutureless and relatively smaller incision has similar advantages to phacoemulsification and is affordable; hence, it is a good alternative to phacoemulsification.
In this study using both techniques, it was found that both techniques can give excellent visual results. However, it was found that there is an increased incidence of posterior capsule opacification in the manual small incision cataract surgery group  .
| Conclusion|| |
Significant and equal ECls occur following the two studied techniques. APT and nuclear grade have positive correlation with higher ECL. Age, sex, and axial length do not affect ECL.
CCT increases significantly and equally postoperatively following the two techniques. Divide and conquer is the easiest technique, whereas phaco chop is the most difficult technique and it needs longer training curve.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]