|Year : 2016 | Volume
| Issue : 3 | Page : 612-615
Phacoemulsification by using the quick-chop and the divide and conquer techniques: a prospective comparative study
Hoda M. K. El-Sobky1, Faried M. W. Faried1, Mohamed G. A. Hassan2
1 Department of Ophthalmology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Ophthalmology, Nasser Institute for Research and Treatment, Cairo, Egypt
|Date of Submission||18-Mar-2015|
|Date of Acceptance||28-Jun-2015|
|Date of Web Publication||23-Jan-2017|
Mohamed G. A. Hassan
16, Cornish El Nil Street, New Benha, Kalubia, 13731
Source of Support: None, Conflict of Interest: None
The aim of the present study was to show the differences between the quick-chop and the divide and conquer techniques regarding phacoemulsification time and the operative effect on corneal endothelium.
Phacoemulsification techniques continue to evolve with the goal of providing safer and more effective methods of cataract extraction.
Patients and methods
Fifty eyes of 49 patients were enrolled in this prospective comparative study. All eyes had nuclear cataracts of grades I-IV according to the Lens Opacities Classification System III. This study involved two groups, each having an equal number of eyes (25). The technique used for group A was the quick-chop phacoemulsification, and for group B it was the divide and conquer phacoemulsification. Preoperative and postoperative assessments included best corrected visual acuity, intraocular pressure, slit-lamp evaluation, and fundoscopic evaluation. Endothelial cell density was measured preoperatively and 3 months postoperatively. All surgeries were carried out at Menoufia University Hospital between March 2013 and October 2014 using the Geuder Megatron G.
In the quick-chop group, the mean equivalent ultrasound time was 12.6 s and endothelial cell loss 3 months postoperatively was 7.44%. In the divide and conquer group, the mean equivalent ultrasound time was 19.99 s and the mean endothelial cell loss 3 months postoperatively was 8.72%.
The quick-chop phacoemulsification technique consumes less time than does the divide and conquer technique, with statistically significant differences. The quick-chop technique also has a lesser impact on the corneal endothelium than does the divide and conquer technique, with statistically insignificant difference.
Keywords: corneal endothelial count, divide and conquer, equivalent phaco time, quick chop
|How to cite this article:|
El-Sobky HM, Faried FM, Hassan MG. Phacoemulsification by using the quick-chop and the divide and conquer techniques: a prospective comparative study. Menoufia Med J 2016;29:612-5
|How to cite this URL:|
El-Sobky HM, Faried FM, Hassan MG. Phacoemulsification by using the quick-chop and the divide and conquer techniques: a prospective comparative study. Menoufia Med J [serial online] 2016 [cited 2020 Feb 17];29:612-5. Available from: http://www.mmj.eg.net/text.asp?2016/29/3/612/198741
| Introduction|| |
During the past two decades, ophthalmologists have become increasingly convinced that the amount of phaco energy delivered in an eye directly affects the corneal endothelial cells and, in some cases, causes corneal decompensation and compromised vision, and thus surgical techniques aimed at minimizing the iatrogenic effects of phaco energy have evolved rapidly  .
The phaco chopping techniques take advantage of the natural cleavage planes of the lens to divide the nucleus using minimal mechanical forces instead of ultrasound energy. The main benefits of the technique are reduction of total ultrasound energy and phacoemulsification time and decreased stress on the zonules  .
The technique of 'divide and conquer', modified by Shepherd  , is quite popular because it is very systematic, uses more of ultrasound than does the 'quick chop', and does not require high vacuum.
During phacoemulsification, heat transferred from the probe to the cornea can result in stromal shrinkage. A phaco tip held too close to the corneal endothelium allows the ultrasonic energy to injure and cause loss of the endothelial cells .
Uncomplicated phacoemulsification does not cause acceleration of diabetic retinopathy postoperatively  , but surgical trauma during phacoemulsification leads to the loss of corneal endothelial cells, and because these cells do not regenerate, most studies evaluating the safety of new assessment techniques involve reducing corneal endothelial cell density (ECD) on specular microscopy  .
| Patients and methods|| |
Fifty eyes of 49 patients were enrolled in this prospective comparative study. A comparison was made between group A, which included 25 eyes who had phacoemulsification using the phaco quick-chop technique, and group B, which included 25 eyes who had phacoemulsification using the divide and conquer technique.
All surgeries were carried out at Menoufia University Hospital between March 2013 and October 2014 using the Geuder Megatron G (GEUDER AG, Heidelberg, Germany).
All eyes had nuclear cataracts of grades I-IV according to the Lens Opacities Classification System III. All eyes had a corneal endothelial cell count greater than 1500/mm 2 , best corrected visual acuity of 6/18 or worse, normal intraocular pressure, transparent central cornea, and pupil dilatation at the preoperative examination of at least 6 mm. Eyes with corneal endothelial dystrophies, pseudoexfoliation, synechia, zonulolysis, history of uveitis, history of ocular trauma, posterior segment abnormalities, or retinopathies were excluded from the study.
All the preoperative and postoperative assessments were performed by one ophthalmologist. Preoperative and postoperative assessments included best corrected visual acuity, intraocular pressure measurement by using Goldmann's applanation tonometry, slit-lamp evaluation, and fundoscopic evaluation. ECD was measured preoperatively and 3 months postoperatively using the noncontact Konan incorporation specular microscope. Geuder Megatron G was used in all cases.
All patients were subjected to retrobulbar local anesthesia. A clear corneal incision was made by using a disposable keratome (3.2 mm). Two side port incisions were made 90 from the clear corneal temporal incision on either side by using an MVR knife (20 G). Continuous curvilinear capsulorhexis were made using cystitome and forceps. Hydrodissection was done to mobilize the nucleus by facilitating cleavage between the cortex, nucleus, and epinucleus. In group A, the phaco quick-chop technique was used, whereas in group B, the divide and conquer technique was used. The incision was widened to 3.5-4 mm using a keratome. Foldable posterior chamber Intraocular lens was implanted, or the 5 mm polymethylmethacrylate posterior chamber IOL was implanted. Irrigation aspiration of the viscoelastic material was carried out using the bimanual technique or a double-way cannula. Hydration of the lips of the corneal incision and the side port incision or a single 10/0 (nylon) interrupted suture was used. Subconjunctival injection of a combination of antibiotics and steroids was given to the patients.
The parameters of the machine were as follows: vacuum 180 mmHg, ultrasound 70%, aspiration flow rate 20 ml/min, and infusion bottle height 75 cm. All data were recorded on a report form.
These data were tabulated and analyzed using the computer program the statistical package for social science (SPSS, version 16; SPSS Inc., IBM, New York,USA).
| Results|| |
Group A included six (24%) men and 19 (76%) women; their mean age was 59.36 ± 6.59 years (range: 43-72 years). Group B included 13 (52%) men and 12 (48%) women; their mean age was 59.88 ± 6.14 years (range: 49-69 years). The difference was not statistically significant (P = 0.774, NS).
As regards the equivalent phaco time, the ultrasound power in both groups was 70% for all cases. The mean equivalent ultrasound time in group A was 12.6 ± 4.29 s (range: 6.3-21.7 s). In group B, the mean equivalent ultrasound time was 19.99 ± 4.31 s (range: 13.3-28.7 s) and the difference between the two groups was statistically significant (P = 0.001, HS).
As regards corneal endothelial cell count and cell loss, the mean preoperative endothelial cell count in group A was 2469.7 ± 516.91 cells/mm 2 (range: 1477-3663 cells/mm 2 ). In group B, the mean preoperative endothelial cell count was 2369.7 ± 366.29 cells/mm 2 (range: 1432-3118 cells/mm 2 ). The difference between the two groups was not statistically significant (P = 0.434 NS).
The mean endothelial cell count 3 months postoperatively in group A was 2286.4 ± 480.02 cells/mm 2 (range: 1288-3461 cells/mm 2 ). In group B, the mean endothelial cell count 3 months postoperatively was 2150.7 ± 339.37 cells/mm 2 (range: 1343-2875 cells/mm 2 ). The difference between the two groups was not statistically significant (P = 0.254 NS).
The mean endothelial cell loss 3 months postoperatively in group A was 191.24 (7.44%) ± 100.58 (3.1%) cells/mm 2 [range: 52 (2.87%)-440 (12.94%) cells/mm 2 ]. In group B, the mean endothelial cell loss 3 months postoperatively was 204.2 (8.72%) ± 86.08 (3.5%) cells/mm 2 [range: 24 (0.94%)-352 (15.92%) cells/mm 2 ]. The difference in endothelial cell loss 3 months postoperatively between the two groups was not statistically significant (P = 0.627, NS) ([Table 1], [Table 2], [Table 3] and [Table 4]).
|Table 3 Ultrasound power, phaco time and equivalent phaco time in groups A and B |
Click here to view
| Discussion|| |
Many studies have compared the phaco quick-chop and the divide and conquer techniques in terms of phaco time, equivalent phaco time, intraoperative and postoperative complications, and postoperative visual acuity. These studies found a statistically significant advantage of the phaco quick-chop over the divide and conquer technique as regards phaco power and duration. The phaco quick-chop technique requires significantly less equivalent phaco time and phaco power than does the divide and conquer technique. A significantly less endothelial cell loss by using the phaco quick-chop technique has been reported  .
In this study conducted on 50 eyes (25 eyes in each group), the mean equivalent phacoemulsification time was 12.6 s in the phaco quick-chop group and 19.99 s in the divide and conquer group. The mean ultrasound time was 18 and 27.72 s, respectively. The mean preoperative ECD was 2469.7 cells/mm 2 in the phaco quick-chop group and 2369.7 cells/mm 2 in the phaco fracture group. Three months postoperatively, the ECD was 2286.4 and 2150.7 cells/mm 2 , respectively. The mean cell loss was 7.44 and 8.72%, respectively.
The data obtained show that the mean ultrasound time and the mean endothelial cell loss in the divide and conquer technique was more than that in the phaco quick-chop technique.
This is in agreement with the results found by Pirazzoli and colleagues, who reached threefold difference between the two techniques of phacoemulsification. Their study included 100 patients (50 patients in each group). The mean equivalent phacoemulsification time was 25.53 s in the phaco-chop group and 87.26 s in the four quadrants phaco fracture group. The mean ultrasound time was 63.7 and 152.58 s, respectively. The mean preoperative ECD was 2623 cells/mm 2 in the phaco-chop group and 2590 cells/mm 2 in the phaco fracture group. Postoperatively, it was 2499 and 2233 cells/mm 2 , respectively. The mean cell loss was 4.72 and 13.8%, respectively  .
As regards the effective ultrasound time, Elnaby and colleagues reported that mean effective ultrasound time in group A (the phaco prechop group) was 19.36 ± 8.51 s, and in group B (the divide and conquer group), it was 24.44 ± 7.86 s, with a statistically significant difference between the two groups. The mean endothelial cell count 3 months postoperatively in group A was 2139.88 cells/mm 2 . In group B, the mean endothelial cell count 3 months postoperatively was 2087.08 cells/mm 2 . The difference between the two groups preoperatively was statistically insignificant. However, the difference in endothelial cell loss 3 months postoperatively between the two groups was statistically significant  .
In this study the percentage of endothelial cell loss was 7.44 ± 3.1 in group A (the phaco quick-chop group) and 8.72 ± 3.5 in group B (the divide and conquer group). Comparative studies evaluating the percentage of cell loss after phacoemulsification have been reported.
Elnaby E and walkob T  reported a mean endothelial cell loss of 11.9% 12 weeks after phacoemulsification. In this study, both the supracapsular phacoemulsification technique and the stop and chop phacoemulsification technique resulted in endothelial cell loss in the same range, reported by the above-mentioned authors; the mean endothelial cell loss was 11.06% after the supracapsular phacoemulsification technique, and 10.11% after the endocapsular technique. Thus, both techniques affected corneal endothelial cells to the same extent with no significant difference.
Paulsen et al.  reported that the mean cell loss was 173 cells/mm 2 (6.3%) and 155 cells/mm 2 (5.7%) at 3 and 12 months, respectively, in the phaco-chop group and 138 cells/mm 2 (5.0%) and 94 cells/mm 2 (3.5%), respectively, in the divide and conquer group. The difference between the two groups was not significant at either follow-up. Other studies reported endothelial cell loss lower than that observed in this study  .
The data show that the phaco quick-chop technique appears to reduce endothelial cell damage. However, the results were based on a small series without the information on cell morphology. More studies on endothelial cell loss should be carried out in the future with the goal of increasing the safety of phacoemulsification.
| Conclusion|| |
In this study we concluded that there is a relationship between the phaco time used and the endothelial cell loss in both techniques: the longer the phaco time used, the more the endothelial cell loss. The phaco quick-chop technique has fewer steps and requires minimal manipulation of intraocular instruments. Thus, the results are efficient and predictable for all nuclear densities.
Authors' contribution: Hoda M. Kamel El-Sobky: concepts, design, definition of intellectual content; Faried M.W. Faried, manuscript preparation, manuscript editing, and manuscript review; Mohamed G.A. Hassan, clinical studies, data acquisition, data analysis and statistical analysis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]