|Year : 2017 | Volume
| Issue : 2 | Page : 492-495
Evaluation of the corneal endothelium by specular microscopy in torsional phacoemulsification versus longitudinal phacoemulsification
Mostafa K Nassar, Osama A Al-Morsi, Alaa M Abdel-Gayd, Salah M Helmy
Department of Ophthalmology, Faculty of Medicine, Menoufiya University, Menoufia, Egypt
|Date of Submission||29-Mar-2016|
|Date of Acceptance||26-Jun-2016|
|Date of Web Publication||25-Sep-2017|
Salah M Helmy
Albednganya, Santa, 32512
Source of Support: None, Conflict of Interest: None
The objective of this study was to compare the effect of cataract extraction by torsional and longitudinal phacoemulsification on the integrity of the corneal endothelium.
Endothelial cell loss remains a well-known, undesirable side effect of cataract surgery. Torsional phaco has a lower mean needle time, less chatter, and improved followability compared with longitudinal phaco.
Patients and methods
This is a prospective randomized study for comparative analysis of corneal endothelial modifications (central cell density and cell loss) following torsional versus longitudinal phaco. A total of 50 eyes included had nuclear cataract grade 3. Divide-and-conquer technique was used for surgeries using Infiniti, Ozil Technology phacomachine. Cases were distributed randomly into two groups: group I included 25 eyes for which torsional phaco surgery was performed, and group II included 25 eyes for which longitudinal phaco surgery was performed.
In group I, the P value that expresses the change between preoperative and postoperative endothelial counts was 0.001, which is statistically significant (P < 0.05), and in group II the P value that expresses the change between preoperative and postoperative endothelial counts was also 0.001, which is statistically significant (P < 0.05). On comparing two groups regarding the percentage of endothelial loss, the P value was 0.159, which shows no statistically significant difference (P > 0.05) between the two groups.
There was no significant difference on comparing the two types of phacoemulsification, as regards the postoperative corneal endothelial cell loss and best-corrected visual acuity.
Keywords: corneal endothelium, longitudinal phacoemulsification, specular microscopy, torsional phacoemulsification
|How to cite this article:|
Nassar MK, Al-Morsi OA, Abdel-Gayd AM, Helmy SM. Evaluation of the corneal endothelium by specular microscopy in torsional phacoemulsification versus longitudinal phacoemulsification. Menoufia Med J 2017;30:492-5
|How to cite this URL:|
Nassar MK, Al-Morsi OA, Abdel-Gayd AM, Helmy SM. Evaluation of the corneal endothelium by specular microscopy in torsional phacoemulsification versus longitudinal phacoemulsification. Menoufia Med J [serial online] 2017 [cited 2019 Apr 21];30:492-5. Available from: http://www.mmj.eg.net/text.asp?2017/30/2/492/215435
| Introduction|| |
The cornea consists of five layers: epithelium, Bowman's layer, stroma, Descemt's membrane, and endothelium. The endothelium is the most posterior layer of the cornea, which is responsible for keeping the cornea dehydrated . Corneal endothelial cell loss remains a well-known, undesirable side effect of cataract surgery that may, in severe cases, negatively affect patients' postoperative visual outcomes .
Endothelial injury may occur during cataract surgery because of a number of factors such as corneal distortion, aspiration of nuclear fragments, intraocular lens contact, and release of free radicals . The corneal endothelial cell layer cannot regenerate after injury. Repair process involves enlargement of the residual cells, amitotic nucleus division, migration, and rossette phenomenon, which leads to reduction in cell density, a proportional increase in mean cell size, and disruption of the normal hexagonal cell pattern .
Torsional phacoemulsification machines, compared with the longitudinal machines, have a lower mean needle time, less chatter, and improved followability. This corresponded to less corneal edema 1 day postoperatively and better visual acuity . Advances in surgical techniques, the implementation of newer surgical technologies such as torsional ultrasound and viscoelastic devices, and aspects of patients' preexisting medical history may lead to varying degrees of endothelial cell loss after cataract surgery; in addition, the torsional phacoemulsification offers less repulsion and less heat energy generation with higher efficiency, decreasing corneal endothelial loss . The aim of this study is to evaluate the corneal endothelium by specular microscopy in torsional phacoemulsification versus longitudinal phacoemulsification.
| Patients and Methods|| |
This is a prospective randomized study that included a total of 50 eyes with nuclear cataract grade 3 that had undergone uneventful phacoemulsification surgeries. Cases were recruited from the outpatient clinic of ophthalmology at Memorial Institute of Ophthalmological Research, Giza, during the period of study from February 2015 to December 2015. All patients were informed about the nature of the study and the forms of treatment they received, and they signed an informed written consent form before starting the study.
In this study, a comparative analysis of corneal endothelial modifications (central cell density and cell loss) following torsional phacoemulsification versus longitudinal phacoemulsification was performed. Age range of patients was from 40 to 70 years. Divide-and-conquer technique was used for phacoemulsification using Infiniti, Ozil Technology (INFINITI® Vision, Alcon, Texas, USA) a phacomachine.
The cases were divided into two groups:
- Group A included 25 eyes for which torsional phacoemulsificaton surgery was performed
- Group B included 25 eyes for which longitudinal phacoemulsificaton was performed.
The criteria of patient inclusion were immature senile cataract (all of same grade, nuclear 3), clear cornea with no evidence of endothelial disease, dilatable pupil, normal anterior chamber depth, and no active ocular disease or inflammation.
The criteria of patient exclusion were history of previous intraocular surgery, the presence of any corneal opacity, corneal endothelial disease, scarring or dystrophies, e.g., Fuch's dystrophy, corneal guttata, glaucomatous patients, patients with mature and hyper-mature senile cataract, pseudoexfoliation syndrome, and patients with an endothelial cell count less than 1900 cells/mm 2.
All patients of both groups underwent preoperative assessment in the following manner: anterior segment examination by slit lamp (Haag-Streit, Mason, OH, USA), measuring intraocular pressure (applanation tonometer), posterior segment examination by 90 lens (Volk), calculation of intraocular lens power (SRK-T formula), and corneal endothelial cell count (central area) with specular microscopy (Topcon SP-2000 specular microscope, Lynmar Blvd, Tampa, FL, USA).
All surgeries were performed by the same right-handed surgeon. For all patients, mydriasis was achieved using tropicamide 1%, cyclopentolat 1%, and phenylephrine 10%. Peribulbar anesthesia was used with lidocain 2% mixed with bupivacaine 0.5%. Conjunctival sac was rinsed with povidone–iodine 5%. Clear corneal incision was performed with keratome 2.2 mm. Sodium hyaluronate 1% (Healon) was injected in the anterior chamber. Capsulorrhexis was created using a capsulorrhexis forceps (Utrata forceps). Two side ports were made at 3 and 9 o'clock. Hydrodissection and hydrodelineation were performed with rotation of the nucleus. Phacoemulsification was performed using Infiniti, Ozil technology phacomachine, with a Kelman 30° beveled phaco tip.
In torsional phaco cases, continuous mode was used, and the parameters during sculpting (phaco 1) were as follows: 25.6 kHz power, 80 cm bottle height, 24 ml/min flow rate, and 50 mmHg vacuum. During phacoemulsification (phaco 2) the parameters were as follows: 19.2 kHz power, 100 cm bottle height, 28 ml/min flow rate, and 300 mmHg vacuum.
In longitudinal phaco cases, pulse mode was used and phaco power was decreased to be 60% during sculpting (phaco 1) and 40% during phacoemulsification (phaco 2), whereas other parameters were kept the same as the torsional group.
The divide-and-conquer technique was used, followed by aspiration of the cortex using bimanual technique, and again healon was injected to fill the anterior chamber and capsular bag. The corneal tunnel is enlarged to 3 mm to allow implantation of a foldable acrylic hydrophilic single-piece intraocular lens inside the capsular bag. The healon was aspirated by bimanual irrigation\aspiration, and the corneal tunnel and side ports were sealed by stromal hydration. Subconjunctival gentamicin and dexamethasone were injected at the end of the surgery. The patients used prednisolone 1% and moxifloxacin 0.5% eye drops five times daily postoperatively.
Postoperative follow-up plan
All patients of both groups were followed up at 1 day, 1 week, and 1 month after surgery, performing specular microscopy at 1 month postoperatively, and then it was compared with the preoperative specular microscopy.
| Results|| |
The current study included 50 eyes: 25 eyes received torsional phacoemulsification, whereas the other 25 eyes received longitudinal phacoemulsification on randomized basis. In all, 54% of cases (27 cases) were female and 46% (23 cases) were male [Table 1]. Mean age and SD in the torsional group was 57.08 ± 7.0, and in longitudinal group it was 56.36 ± 7.57 [Table 2]. There was no statistically significant difference between the two study groups regarding sex and age (P > 0.05 for all), indicating homogeneity of the study groups.
|Table 1: Comparison between torsional phaco and longitudinal phaco according to sex|
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|Table 2: Comparison between torsional phaco and longitudinal phaco according to age|
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In the torsional phaco group, the mean preoperative endothelial cell count was 3114.9 ± 574.77 cells/mm 2. At 1 month postoperatively, the mean count was 2662.2 ± 527.4 cells/mm 2. The P value that expresses the change between the preoperative and the postoperative endothelial counts was 0.001, which is statistically significant (P < 0.05) [Table 3]. The percentage of endothelial cell loss was 14.68 ± 3.31%.
|Table 3: Comparison between preoperative endothelial count and postoperative endothelial count in the torsional phaco group|
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In the longitudinal phaco group, the mean preoperative endothelial cell count was 2732.5 ± 419.88 cells/mm 2. At 1 month postoperatively, the mean count was 2303.3 ± 415.29 cells/mm 2. The P value that expresses the change between the preoperative and the postoperative endothelial counts was also 0.001, which is also statistically significant (P < 0.05) [Table 4]. The percentage of endothelial cell loss was 15.95 ± 2.96% [Table 5].
|Table 4: Comparison between preoperative endothelial count and postoperative endothelial count in the longitudinal phaco group|
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|Table 5: Comparison between torsional phaco and longitudinal phaco according to the percentage of endothelial cell loss|
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On comparing between the torsional phaco and longitudinal phaco groups regarding the percentage of endothelial loss, the P value was 0.159, which shows no statistically significant difference (P > 0.05) between the two groups [Table 5].
| Discussion|| |
In the current study, mean loss in the torsional phacoemulsification group was 14.68% and in the longitudinal phacoemulsification group it was 15.95% after 1 month, which showed no statistically significant difference in endothelial cell loss.
Our postoperative examination was scheduled based on the studies by Kohlhaas et al. , who found no further endothelial cell loss after 4 weeks, and Price et al. , who also found that most cell loss occurred within the first month after surgery. Therefore, we did a postoperative endothelial count after 1 month.
There was no significant difference in central endothelial cell loss between the torsional group and the longitudinal group in our study, and our results in each group are similar to those in a study by Bozkurt et al.  (4.2 ± 5.7%, torsional group; 6.7 ± 3.3%, conventional group). Bozkurt and colleagues conclude that the torsional mode appears to cause less loss of corneal endothelial cells, although not statistically significantly, but their results are from the second postoperative month in 100 eyes, and another difference is that they used a stop-and-chop technique for cataract removal; nevertheless, these differences might not be the reason for the slightly greater endothelial cell loss in our study. Storr-Paulsen et al. , suggest that divide-and-conquer and phaco-chop techniques are safe and with the same amount of endothelial cell loss.
Another study by Reuschel , included 148 patients: 72 received torsional phaco and 76 received longitudinal phaco, and they found no statistically significant difference in endothelial cell loss in the torsional group (7.2 ± 4.6%) and the longitudinal group (7.1 ± 4.4%), as the P value was 0.906, which is similar to our study (P = 0.159).
In their study of 525 eyes, Liu et al. , found a significantly lower cell decrease (12.5%) in the torsional group than in the conventional phaco group (19.1%), which is different when compared with our study results in which there were no significant differences between the two groups. Another difference in their study is that they used a different method of cataract removal. They used a quick-chop technique rather than nonchopping techniques; the quick-chop technique seems to have higher endothelial cell loss, as reported by Zeng et al. .
In 2013, Gonen et al.  conducted a study that involved 70 eyes with highly dense cataract (more than nuclear grade 3): 35 eyes received torsional phaco and 35 received longitudinal phaco, and the percentage of mean endothelial cell loss in both groups was between 35.4 and 39.1%, which is higher than our study because of the highly dense cataract they worked on, but there was no statistically significant difference between the two groups (P > 0.05) as our study concluded.
| Conclusion|| |
Cataract extraction constitutes the largest surgical workload in ophthalmic units throughout the world. In the hands of experienced surgeons, both phacoemulsification types, longitudinal and torsional, achieved excellent visual outcomes. On comparing the two types of phacoemulsifications, as regards the postoperative corneal endothelial cell loss and best-corrected visual acuity, we found no clinical or statistically significant difference, which means that both types of phacoemulsifications are equal to each other, and thus each surgeon can determine the preferred type of phacoemulsification according to his own experience; however, the surgeon has to take into consideration that in longitudinal phaco the preferred mode is the pulse mode with high vacuum and low power to decrease repulsion and heat production, whereas in torsional phaco the preferred mode is the continuous mode with medium vacuum, which is sufficient to pull the material through, as the repulsion and heat production in torsional phaco are much less than that in longitudinal phaco.
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], [Table 5]