Torsional Group Research Articles

Effect of longitudinal and torsional ultrasound on corneal endothelial cells: experimental study in rabbit eyes.

To compare corneal endothelial damage from longitudinal and torsional ultrasound during phacoemulsification. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. 9 New Zealand white rabbits underwent bilateral surgery. After incision, the Intrepid Balanced Tip of the Centurion Ozil handpiece was inserted into the anterior chamber, and the following settings were used: 50 mL/min flow, 70 mm Hg intraocular pressure, 600 mm Hg vacuum, and 60% longitudinal (1 eye) or torsional (contralateral eye) ultrasound for 30 seconds. Cumulative dissipated energy (CDE) was noted. After euthanasia and enucleation, the corneas were removed, stained with trypan blue/alizarin red, and photographed (400× photographs from 5 specific areas and 1 overview photograph from each corneal button). The ImageJ program was used to evaluate cell damage and loss in the photographs obtained from each cornea. Cavitation bubbles around the phacoemulsification tip were generally observed in the longitudinal group. CDE was 17.4 ± 0.58 and 6.93 ± 0.15 in the longitudinal and torsional groups, respectively (P = .003). The percentage of intact cells was statistically higher in the torsional group (94.22% ± 5.99% vs 56.85% ± 22.29%), and the percentage of lost cells was statistically higher in the longitudinal group (42.10% ± 22.02% vs 4.97% ± 6.23%) (P = .003). This was observed in the analysis of the 400× photographs and the overview photographs. This study suggests that torsional ultrasound was associated with significantly less corneal endothelial cell damage than classical longitudinal tip motion, providing further insight on mechanisms of corneal endothelial damage during phacoemulsification.

Transvers ve Torsiyonel Fakoemülsifikasyon ile Biaksiyel Mikroinsizyon Katarakt Cerrahisinde Saydam Korneal Kesi Değişikliklerinin Karşılaştırılması: Kohort Çalışması

Objective: To compare the effects of transverse versus torsional phacoemulsification by using the biaxial microincision cataract surgery technique on corneal structures and clear corneal incision (CCI) morphology. Material and Methods: We evaluated comparative case series of patients with moderate density nuclear cataracts who underwent biaxial microincision transverse or torsional phacoemulsification. Seventy patients have included in the study and they were divided into 2 groups: transverse and torsional. The main outcome measures included, corrected distance visual acuity, central corneal thickness, central corneal endothelial cell density, endothelial cell loss (ECL), and changes in the CCI morphology. Results: Each group comprised 35 (35 eyes) patients. Epithelial misalignment on the CCI morphology was highly significantly meaningful with the transverse group on the postoperative first day (p<0.001). Descemet membrane detachment on the first day postoperatively was high in both groups, especially in the transverse group, but the difference was not statistically significant (p=0.073). In the postoperative 3rd month, the mean ECL was 23.6% in the transverse group, and 19.0% in the torsional group, and there was no statistically significant difference between groups (p=0.187). Conclusion: In biaxial microincision cataract surgery, the corneal damage caused by transverse phacoemulsification seems to be higher compared to the torsional mode.

Comparative study of conventional versus torsional phacoemulsification in management of hard nucleus

Background Phacoemulsification acoenergy and shortening the phacotime can decrease this risk. Aim The aim of this work is to compare the safety and the efficiency of phacoemulsification using conventional and torsional ultrasound modalities for hard nucleus cataracts. Settings and design This was a prospective randomized interventional study. Patients and methods A total of 30 eyes of 29 patients having hard nuclear cataract (grades IV and V) were divided into two groups. Group A included 15 eyes whose cataract was operated on by conventional phacoemulsification using the Infiniti machine. Group B included 15 eyes whose cataract was operated on by torsional phacoemulsification using the OZil technology of the Infiniti machine. Intraoperative ultrasound time and cumulative dissipated energy were recorded. Postoperative central corneal thickness (CCT) was measured at days 1, 7, and 30, and specular microscopy was done at 1 month. Statistical analysis The collected data were coded, tabulated, and statistically analyzed. Results The mean ultrasound time and cumulative dissipated energy and the amount of irrigating fluid were significantly higher in group A. There was a highly significant decrease in endothelial cell count (ECC) in both groups. ECC was significantly lower in the conventional group than in the torsional group at 1 month postoperatively. CCT in both groups was significantly increased at day 1 and then decreased at 1 week and 1 month but was still significantly higher than the preoperative level. CCT became higher in the conventional group than in the torsional group at all follow-up times, but this was significant only at day 1 and week 1 and not significant at 1 month. Conclusion Both ultrasound modalities can be used in hard nucleus phacoemulsification. However, the torsional ultrasound proved to be safer. The choice between these technologies is of particular importance when operating eyes with low ECC.

Effect of autoclave sterilization on cyclic fatigue and torsional fracture resistance of NiTi rotary instruments.

The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigue and torsional fracture resistance of ProTaper Universal (PTU), K3XF, HyFlex EDM (EDM), and TF adaptive (TFA). Sixty instruments from each file type were divided into two categories for cyclic fatigue group (CGr) and torsional fracture group (TGr). CGr and TGr were divided into three subgroups, respectively, consisting of ten instruments from each file type. Cyclic fatigue fracture test was performed using artificial canal made of stainless steel, and the mean number of cycles to failure (NCF) were determined. CGr1, the files were tested to establish baseline for NCF; CGr2, the files were tested cyclic fatigue after 10 cycles of autoclave; CGr3, instruments were autoclaved after being cycled to 25, 50, and 75% of corresponding NCF determined in CGr1, followed by cyclic fatigue test. The torsional fracture test was performed without autoclave (TGr1), after 3-cycle autoclave (TGr2), and 7-cycle autoclave (TGr3), respectively, which evaluated maximum torque and angular deflection. NCF, maximum torque and angular deflection were compared using one-way ANOVA with Bonferroni test. Two-way ANOVA was performed to determine the interaction between 'autoclave treatment' and 'type of NiTi file'. EDM showed highest NCF within the same autoclave treatment. TFA presented the lowest maximum torque and the highest angular deflection, and PTU presented the lowest angular deflection. Within the same NiTi file systems, most of NCF, maximum torque and angular deflection of tested files were not significantly influenced by autoclave condition.

Corneal Endothelial and Central Corneal Thickness Changes after non Complicated Uneventful Phacoemulsification

Aim of the work: this study aimed to evaluate the central corneal thickness and the corneal endothelium by specular microscopy in torsional phacoemulsification versus longitudinal phacoemulsification. Methods: in our study we did a comparative analysis of the changes in endothelial cells of the cornea (Central cell density and cell loss) and central corneal thickness after cataract extraction surgeries by torsional phacoemulsification versus longitudinal phacoemulsification. In our study thirty eyes of thirty patients were chosen from Ophthalmology clinic at Bab Al-Shaariah University Hospital for uneventful phacoemulsification surgeries (15 eyes of 15 patiens for torsional phaco and 15 eyes of 15 patients for longitudinal phaco). The types and densities of cataract were determined as cortical, posterior supcapsular (PSC), nuclear I, nuclear II and nuclear III. Divide and Conquer technique was used for phacoemulsification using (Infiniti, Ozil technology, Alcon) phaco machine. A noncontact specular microscope Topcon SP-1P (Topcon Corporation, Japan) was used to evaluate the central endothelial cell density (CD) and central corneal thickness (CCT). Results: The mean U/S time was lower in the torsional group than in the longitudinal group (p 0.05) and higher average corneal endothelial cell losses at 2 weeks postoperative (p > 0.05). Conclusions: our study suggested a better efficiency by the torsional mode rather than the longitudinal mode.

The Impact of Reused Phaco Tip on Outcomes of Phacoemulsification Surgery

ABSTRACTPurpose: To evaluate the impact of reused phaco tip on intraoperative performance and postoperative outcomes after 2.2 mm micro-coaxial torsional and transversal phacoemulsification.Material and Methods: This prospective randomized study enrolled 136 eyes of 136 cataract patients; 68 eyes in torsional group (34 eyes with single use tip, 34 eyes with reused tip) and 68 eyes in transversal group (34 eyes with single use tip, 34 eyes with reused tip). Intraoperative measurements were total ultrasound (U/S) time, torsional U/S time, cumulative dissipated energy (CDE), estimated fluid use (EFU) in the torsional group and total phacoemulsification time (TPT), and effective phacoemulsification time (EPT) in transversal phacoemulsification. The central endothelial cell density (ECD) and the central corneal thickness (CCT) were evaluated preoperatively and postoperatively at 1 and 30 days using noncontact specular microscopy.Results: Intraoperative measurements in torsional phacoemulsification showed significant increase in total U/S time (p = 0.01), torsional U/S time (p = 0.01), and CDE (p = 0.01) with the reused tip. The EFU was similar in both tip groups (p = 0.36). The total U/S time, torsional U/S time, and CDE in torsional group were significantly increased with the reused tip for grade III (p = 0.03 for all parameters) and grade IV cataracts (p = 0.005 for torsional U/S time and CDE; p = 0.006 for total U/S time). Intraoperative measurements in transversal phacoemulsification showed no differences in TPT and EPT between tip groups (p > 0.05). The change in ECD and CCT in torsional and transversal phacoemulsification groups were similar in both tip groups (p > 0.05).Conclusions: This study showed that sharpness of phaco tip edge increases the efficiency of torsional phacoemulsification for hard cataracts. This result does not mean that reused phaco tip may be used in soft and medium cataracts. As the timing of tip’s change is a user-dependent procedure, a new single phaco tip should be used in each case if possible.

面外せん断変形を考慮した異方性円筒殻の軸圧縮・ねじりおよび複合荷重に対する閉じた解

Simple, closed-form solutions, which can be easily calculated using spreadsheet software, for thin and moderately thick anisotropic cylinders under torsion, axial compression and these combined loads that includes the effect of transverse shear deformation are derived. Previously derived partial differential equations of equilibrium, which are including both layup anisotropy and transverse shear deformation, are separated two equation groups by neglecting coupling stiffnesses (tension-shear, bending-torsion and tension-torsion couplings). One is tension-bending equation group and the other is torsional equation group, and these equation groups are solved independently and the closed-form solutions are obtained. One of the two tension-bending solutions satisfies a simply supported condition, another a fully fixed condition and both of these can be applied to cylinders that are shorter and longer than the length of the bending boundary layer. In addition, it is shown that previously derived bending-boundary solution can be applied as the same form when the length of the cylinder is longer than the length of its bending boundary layer. Moreover, Donnell-type shallow-shell approximation is inappropriate for solving torsional deformation of moderately thick cylinder is also shown. Comparison between closed-form solution and precise solution including both layup anisotropy and transverse shear deformation shows that the difference can be negligible when cylinder is honeycomb-sandwich with symmetric facesheet but cannot be negligible when the symmetric cylinder has non-negligible tension-torsion coupling stiffnesses. Therefore, the estimation formula for the effect of tension-torsion coupling stiffnesses is also derived.

Phacopower Modulation and the Risk for Postoperative Corneal Decompensation

In compromised corneas, eg, patients with Fuchs endothelial dystrophy (FED), it is of utmost importance to use a phacotechnique that is the least traumatic to the corneal endothelium. Furthermore, preoperative patient selection is crucial, because unexpected corneal decompensation leads to dissatisfied patients. To compare corneal thickness and corneal volume changes using torsional and longitudinal phacoemulsification in patients with Fuchs endothelial dystrophy (FED) and determine risk factors of postoperative corneal decompensation. Prospective randomized clinical trial of all patients diagnosed with FED and planning to undergo cataract surgery for visually significant cataract at a university medical center from November 2008 to May 2010. Fifty-two eyes with FED and visually significant cataract underwent torsional (n = 26) or longitudinal (n = 26) phacoemulsification. Patients were evaluated preoperatively and 1 day, 1 week, 1 month, 3 months, and 6 months postoperatively. Visits included best spectacle-corrected visual acuity, anterior segment optical coherence tomography evaluating central corneal thickness (CCT) and peripheral corneal thickness (PCT), and Scheimpflug imaging calculating corneal volume (CV). Randomization took place according to stage of FED, nucleus density grade, and age. Intraoperatively, ultrasonography time and cumulative dissipated energy were recorded. Central corneal thickness, PCT, and CV. Ultrasonography time and cumulative dissipated energy were significantly lower in the torsional group for harder nucleus density grades compared with the longitudinal group (P = .009 and P = .002, respectively). Peripheral corneal thickness at the 6-o'clock position, CCT, and CV were significantly smaller in the torsional group 1 day postoperatively (P = .002; P = .03; and P = .004, respectively). Changes in PCT at the 12-o'clock position and best spectacle-corrected visual acuity were not significantly different between the 2 groups (P > .05). Preoperative CCT was the only significant predictor of corneal decompensation postoperatively (P < .001). Preoperative CCT of 620 µm corresponded to an odds ratio of 1, meaning no increased risk of developing corneal decompensation. For each 10-µm increase in preoperative CCT, the odds of developing corneal decompensation increased 1.7 times. Torsional phacoemulsification effectively reduces ultrasonography time and cumulative dissipated energy compared with longitudinal phacoemulsification in patients with FED. However, there were only significant differences in corneal thickness and CV changes at 1 day postoperatively in favor of the torsional group. Central corneal thickness more than 620 µm, measured by noncontact pachymetry, leads to an increased risk for corneal decompensation after phacoemulsification in patients with FED. clinicaltrials.gov Identifier: NCT00781027.

Comparison of clear corneal incision injuries between torsional and conventional phacoemulsification

To compare thermal and mechanical clear corneal incision (CCI) injuries after conventional and torsional phacoemulsification. A prospective, randomized clinical study. A total of 80 eyes were evaluated for the profile of the incision at 1 day and 3 months postoperatively. The wound architecture was recorded with anterior segment optical coherence tomography (AS-OCT). The incisional thickness increased by thermal injury, Descemet's membrane detachment (DMD) caused by mechanical injury, the presence of endothelial gaping, loss of coaptation, and wound retraction of the conventional phaco group and the torsional phaco group were compared. The corneal thickness at the incision site of the torsional ultrasound group was significantly lower than the conventional group compared to at the first postoperative visit (1187.55 ± 75.66, 1233.62 ± 85.87, P = .013). However, this thickness was similar between the two groups at 3 months postoperatively. The central endothelial cell loss was significantly lower in the torsional ultrasound group after 3 months (417 ± 143, 322 ± 130, P = .003). There was a positive correlation between cumulated dissipated energy (CDE) and the incisional corneal thickness change that was observed by AS-OCT. Other OCT outcome parameters (such as endothelial gap, DMD, epithelial gap, and uncoaptation) that may be caused by mechanical injury did not differ significantly between the groups on postoperative day one or after 3 months. The torsional ultrasound mode may provide a lower level of phacoemulsification time and energy and induce less incisional corneal thickness caused by thermal injury in the early postoperative period. The long-term wound healing appeared the same in both ultrasound mode groups.

The influence of simulated clinical use on the flexibility of rotary ProTaper Universal, K3 and EndoSequence nickel-titanium instruments

To investigate the influence of cyclic flexural and torsional loading on the flexibility of ProTaper Universal, K3 and EndoSequence nickel-titanium instruments, in view of the hypothesis that these types of loading would decrease the flexibility of the selected NiTi rotary files. The instruments evaluated were S2 and F1 ProTaper Universal, sizes 20 and 25, .06 taper K3, and sizes 20 and 25, .06 taper EndoSequence. Flexibility was determined by 45° bending tests according to ISO 3630-1 specification. Values of the bending moment (MB ) obtained with new instruments were considered as the control group (CG). Bending tests were then conducted in instruments previously fatigued to one-fourth and three-fourths of their average fatigue life (fatigue groups, FG¼ and FG¾), as well as after cyclic torsional loading (torsional group, TG). Fatigue tests were carried out in a bench device that allowed the files to rotate freely inside an artificial canal with an angle of curvature of 45° and a radius of 5mm. Cyclic torsional loading tests were performed that entailed rotating the instrument from zero angular deflection to 180° and then returning to zero applied torque in 20 cycles. Data were analysed using one-way analysis of variance at a significance level of 5%. Simulated clinical use by means of flexural fatigue tests did not affect the flexibility of the instruments, except for a significant increase in flexibility observed in a few instruments (P<0.05). In addition, comparative statistical analyses between the values of MB measured in new instruments and after cyclic torsional loading showed no significant differences between them (P>0.05). The flexibility of rotary ProTaper Universal, K3 and EndoSequence NiTi instruments, measured in bending tests, was not adversely affected by simulated clinical use in curved root canals.

An anatomical measurement of medial femoral torsion

Medial femoral torsion (MFT) can be corrected with derotational osteotomy. Derotational osteotomies can be performed in the proximal or the distal part of the femur. Similar results have been reported for these two procedures. The aim of this study was to evaluate the pathologic location of the MFT by measuring the degree of infratrochanteric and supratrochanteric torsion (STT) of the femur using computed tomography (CT) scans. The current study was carried out in patients with the chief complaint of an in-toeing gait because of the MFT. Sixty-seven patients were enrolled in the study. Forty-one patients (72 lower extremities) were included in the intervention group; 20 patients were included in the cerebral palsy (CP) group (35 lower extremities) and 21 patients were included in the developmental MFT group [developmental femoral torsional (DF) group, 37 lower extremities]. The control group included 26 patients (33 lower extremities) with uninjured limbs with a femoral or a tibial fracture. In this study, torsional angles [MFT, STT and infratrochanteric torsion (ITT)] were measured on CT scan using picture archiving and communication system measurement tools. To measure the STT and ITT, the most prominent points of the lesser and the greater trochanter were marked on CT scans; these two points were connected and were defined as the intertrochanteric line (ITL). The angle between the ITL and the axis of the femoral neck was defined as the STT. The angle between the ITL and the axis of the condylar axis was defined as the ITT. Two authors measured the MFT, STT, and ITT angles of each femur independently. The twisting of the femur had occurred in a different location for each case. In all groups, however, STT was reduced with increasing age; this change was statistically significantly. ITT of the each group showed a random distribution. The means of the ITT in the control group and the DF group did not change significantly, and that of the CP group tended to decrease with age. MFT of the control group and the DF group reduced significantly with age (P<0.05). The value of MFT in the CP group was steady, without a significant change with age. The pathology of MFT could occur differently in the supratrochanteric, infratrochanteric region, or for both sites in each patient. To avoid another lever arm disease after surgery, the correction of MFT should be performed in the correct position. In the CP group, derotational osteotomy could be performed safely at a younger age compared with the DF group. In addition, the distal femur is the preferable osteotomy site for older CP patients.

REMOVAL OF POSTERIOR SEGMENT RETAINED LENS MATERIAL USING THE OZIL PHACOEMULSIFICATION HANDPIECE VERSUS FRAGMATOME DURING PARS PLANA VITRECTOMY

To assess the utility of the torsional phacoemulsification handpiece compared to the Fragmatome during pars plana vitrectomy for removal of posterior segment retained lens material. : Retrospective comparative case series. Thirty-four eyes of 34 patients at 2 centers who underwent pars plana vitrectomy for retained lens material with either torsional phacoemulsification or the Fragmatome were retrospectively reviewed. Lens material was graded by nuclear density and percentage of total nuclear size. The primary outcome measure was mean change in visual acuity. Secondary outcomes included intraoperative or postoperative complications, occurrence of mechanical malfunctions and metric data including the total ultrasound, phacoemulsification, and torsional times. In the torsional ultrasound group (17 eyes), mean nuclear density was 3.6 and mean size was 63%. Mean initial logarithm of minimum angle of resolution visual acuity was 1.58 (20/760) and improved to 0.66 (20/80) at postoperative Month 3, a gain of 0.92 (P = 0.003). One eye developed a self-limited, peripheral, serous, choroidal detachment intraoperatively, whereas two eyes developed postoperative cystoid macular edema. Mean total ultrasound, phacoemulsification, and torsional times were 76.7, 13.4, and 63.3 seconds, respectively. Mean total operative time to remove retained lens material (excluding vitreous gel removal) was 111 seconds. All the patients demonstrated excellent followability based on independent observations by the surgeons. In the Fragmatome group (17 eyes), initial logarithm of minimum angle of resolution visual acuity was 1.51 (20/640) and improved to 0.6 (20/80) at postoperative Month 3, a gain of 0.91 (P < 0.001). One eye developed a retinal detachment at postoperative Week 2, whereas 3 eyes developed postoperative cystoid macular edema. The use of torsional phacoemulsification during pars plana vitrectomy for retained lens material is a novel approach with potential advantages over the standard 20-gauge Fragmatome, including improved followability and purchase of lens material attributable to the addition of torsional movement.

Comparison of the effect of torsional and microburst longitudinal ultrasound on clear corneal incisions during phacoemulsification

To compare incision integrity after clear corneal microcoaxial phacoemulsification using longitudinal and torsional ultrasound (US). Iladevi Cataract & IOL Research Centre, Ahmedabad, India. Prospective randomized experimental clinical trial. Part 1 comprised an experimental study of rabbit eyes. Group 1 received longitudinal US. Group 2 received torsional US. The right eye of each rabbit served as a control. Samples were processed for histomorphology and collagen I denaturation by immunofluorescence. Part 2comprised a clinical trial of patients. Group 1 received torsional US. Group 2 received longitudinal US. At the end of surgery, trypan blue 0.0125% was instilled. After 2 minutes, 0.1 mL of aqueous was aspirated and its optical density measured. In part 1, incision histomorphology was comparable in both modalities. Collagen denaturation tests (immunofluorescence, dot blot analysis) showed no irregularity in collagen arrangement in either group. In Group 2, Descemet membrane was detached and endothelial cells were minimal at the roof of the incision. In part 2, trypan blue ingress into the anterior chamber wassignificantly greater in Group 1 than in Group 2 (mean 3.40 + 0.6 log units versus and 3.77 + 0.82 log units) (P<.007). Incision histomorphology in the torsional group showed minimal Descemet membrane detachment and minimal endothelial cell loss at the roof of the incision. Minimal ingress of trypan blue into the anterior chamber was observed with torsional US, indicating better wound integrity than with longitudinal US. No author has a financial or proprietary interest in any material or method mentioned.

Effects of antebrachial torsion on the measurement of angulation in the frontal plane: A cadaveric radiographic analysis

To quantify the effect of ante- brachial torsion on the miscalculation of radial valgus measured radiographically and to assess a radiographic positioning method used to mitigate torsion-associated artifactual miscalculation of concurrent frontal plane angulation. A canine cadaveric forelimb was used to model different combinations of valgus and external torsion. Valgus was induced in the limb in increments of five degrees, radiographic images were taken at each increment, and the observed radiographic valgus was measured. Various angles of torsion were then induced and the process was repeated for a range of torsional angles at 15° increments. For the second objective, the study was repeated with the forelimb rotationally re-positioned to mirror the degree of the induced torsion of the deformity at each valgus and torsion iteration. Both zero degrees and 15° torsional iterations possessed mean artifactual valgus (AV) values between zero and five degrees for every valgus increment. With torsion of 30° and higher, mean AV values varied widely and did not fall within the zero to five degree accepted range. Rotationally re-positioning the limb in an attempt to alleviate the AV discrepancies resulted in the 30° torsional group having acceptable AV values for valgus values between zero and 20°. Increasing ante- brachial torsion interferes with accurate radiographic measurement of frontal plane deformities. Radiographically repositioning the limb allows the accurate calculation of more valgus and torsion combinations, but still results in miscalculations of more complex deformities.

Long-Term Comparison of Endothelial Changes Between Torsional and Longitudinal Phacoemulsification.

The objective of this study was to evaluate endothelial changes between torsional and longitudinal phacoemulsification 2 years after cataract surgery. This was a prospective, randomized, controlled clinical trial. We enrolled 200 patients with senile cataract between August 2008 and December 2009 for surgery using either torsional (group A, n = 100) or longitudinal (group B, n = 100) phacoemulsification. Outcomes were central endothelial cell density and corrected distance visual acuity (CDVA) 3 months and in this follow-up 2 years after surgery. Statistical evaluation of endothelial cell loss (ECL) was performed according to statistical guidelines by creating a primary analysis (substitution of missing values by the median) and a secondary analysis (actual data). The mean age was 71 (SD, 7.3) years. We were able to reexamine 46 patients in group A and 54 in group B 2 years after surgery. The median CDVA before surgery was 0.3 logMAR in group A and 0.35 logMAR in group B, improving to 0 logMAR postoperatively in both groups. The median ECL in the primary analysis was 6.9% after 3 months and 10.3% 2 years after surgery in group A. In group B, we found a loss of 6.6% after 3 months and 8.6% 2 years postoperatively. In the secondary analysis, the loss was 10.0% in group A and 8.5% in group B after 2 years. The difference was statistically not significant. There is no difference between the ECL between torsional and longitudinal phacoemulsification up to 2 years after cataract surgery.

The contrast effects of phacoemulsification on hard nuclei with torsional mode and burst mode

Objective To investigate the contrast effects of phacoemulsification on hard nuclei with torsional mode and burst mode.Methods Fifly-one cataract eases(65 eyes)with nuclei density grade of Ⅳ (according to the Emery classification)were comprised in this study.All cases were randomly divided into two groups:torsional group and burst group.The ultrasound time(UST)and cumulative dissipated energy(CDE),corneal edema,best corrected visual acuity(BCVA)and corneal endothelial cell loss were recorded.Results The mean CDE in torsional group was statistically significantly lower than that in burst group(P＜0.05).The difference between the two groups was not statistically significant(P＜0.05).Cornea edema on the first postoperative day in torsional group was statistically significantly better than that in burst group(X2=8.620,P＜0.05),but on the seventh postoperative day,there were no statistically significant differences between the two groups(X2=0.955,P＞0.05).The average best corrected visual acuity in torsional group was statistically significantly better than that in burst group on the first postoperative day(X2=4.975,P＜0.05),but on the seventh and thirtieth postoperative day,there were no statistically significant differences between the two groups(P＞0.05).The mean endothelial cell loss in torsional group was significandy less than that in burst group on the third postoperative month(t=4.317,P＜0.05).Conclusion The intraoperative damage to oeular structures may be miuimized and the level as well as the rapidily of visual rehabilitation may be maximized with the torisional mode during phacoemulsification on hard muclei of cataract surgery. Key words: Phacoemulsification; Hard Muclei; Torsional mode; Burst mode

Torsional ultrasound mode versus combined torsional and conventional ultrasound mode phacoemulsification for eyes with hard cataract

PurposeTo compare torsional versus combined torsional and conventional ultrasound modes in hard cataract surgery regarding ultrasound energy and time and effect on corneal endothelium.SettingsKasr El Aini hospital, Cairo University, and International Eye Hospital, Cairo, Egypt.MethodologyNinety-eight eyes of 63 patients were enrolled in this prospective comparative randomized masked clinical study. All eyes had nuclear cataracts of grades III and IV using the Lens Opacities Classification System III (LOCS III). Two groups were included, each having an equal number of eyes (49). The treatment for group A was combined torsional and conventional US mode phacoemulsification, and for group B torsional US mode phacoemulsification only. Pre- and post-operative assessments included best corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp evaluation, and fundoscopic evaluation. Endothelial cell density (ECD) and central corneal thickness (CCT) were measured preoperatively, 1 day, 7 days, and 1 month postoperatively. All eyes were operated on using the Alcon Infiniti System (Alcon, Fort Worth, TX) with the quick chop technique. All eyes were implanted with AcrySof SA60AT (Alcon) intraocular lens (IOL). The main phaco outcome parameters included the mean ultrasound time (UST), the mean cumulative dissipated energy (CDE), and the percent of average torsional amplitude in position 3 (%TUSiP3).ResultsImprovement in BCVA was statistically significant in both groups (P < 0.001). Comparing UST and CDE for both groups revealed results favoring the pure torsional group (P = 0.002 and P < 0.001 for UST; P = 0.058 and P = 0.009 for CDE). As for %TUSiP3, readings were higher for the pure torsional group (P = 0.03 and P = 0.01). All changes of CCT, and ECD over time were found statistically significant using one-way ANOVA testing (P < 0.001).ConclusionBoth modes are safe in hard cataract surgery, however the pure torsional mode showed less US energy used.

Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification

To compare the intraoperative and postoperative outcomes of conventional longitudinal phacoemulsification and torsional phacoemulsification. Department of Ophthalmology, University of Leipzig, Germany. Randomized single-center clinical trial. Eyes with senile cataract were randomized to have phacoemulsification using the Infiniti Vision System and the torsional mode (OZil) or conventional longitudinal mode. Primary outcomes were corrected distance visual acuity (CDVA) and central endothelial cell density (ECD), calculated according to the Conference on Harmonisation-E9 Guidelines in which missing values were substituted by the median in each group (primary analysis) and the loss was then calculated using actual data (secondary analysis). Secondary outcomes were ultrasound (US) time, cumulative dissipated energy (CDE), and percentage total equivalent power in position 3. Postoperative follow-up was at 3 months. The mean preoperative CDVA was 0.41 logMAR in the torsional group and 0.38 logMAR in the longitudinal group, improving to 0.07 logMAR postoperatively in both groups. The mean ECD loss was 7.2% ± 4.6% in the torsional group (72 patients) and 7.1% ± 4.4% in the longitudinal group (76 patients), with no statistically significant differences in the primary analysis (P = .342) or secondary analysis (P = .906). The mean US time, CDE, and percentage total equivalent power in position 3 were statistically significantly lower in the torsional group (98 patients) than in the longitudinal group (94 patients) (P<.001). The torsional mode was as safe as the longitudinal mode in phacoemulsification for age-related cataract.

Torsional mode phacoemulsification: Effective, safe cataract surgery technique of the future

Purpose:To compare various outcome measures using torsional mode and longitudinal mode in the phacoemulsification of cataract with different nuclear densities.Setting: Magrabi Eye Hospitals, Kingdom of Saudi Arabia.Design: A randomized comparative clinical study.Materials and Methods:This study includes 200 eyes of 156 patients (100 in the ultrasound longitudinal “US” group and 100 in the torsional group). All eyes received AcrySof® single piece intraocular lens (Alcon Surgical, Fort Worth, TX). The primary outcome measures were ultrasound time (UST), cumulative dissipated energy (CDE), and surgical complications. Postoperative outcome measures were the degree of corneal edema on the first postoperative day and final best corrected visual acuity (BCVA) and CCT (central corneal thickness).Results:The differences in UST and CDE between subgroups of nucleus hardness were statistically significant (P < 0.01). The UST and CDE consistently increased in eyes with higher grades of nucleus density. On day one, the mean BCVA was 0.61 ± 0.13 decimals in the ultrasound (US) group and 0.67 ± 0.11 decimals in the torsional group (significant P < 0.05). Corneal edema was significantly less in the torsional group (P < 0.05). At 30 days, the mean BCVA was 0.94 ± 0.22 decimals in the US group and 1.0 ± 0.12 decimals in the torsional group but this difference was not statistically different (P > 0.05).Conclusions:The torsional mode provides an effective and safe method for cataract removal with lower energy usage as compared to longitudinal traditional phacoemulsification. However, the final visual outcome was similar for both study groups.

Comparison of Torsional and Microburst Longitudinal Phacoemulsification: A Prospective, Randomized, Masked Clinical Trial

To compare intraoperative performance and postoperative outcome of three phacoemulsification technologies in patients undergoing microcoaxial phacoemulsification through 2.2-mm corneal incisions. The prospective, randomized, single-masked study included 360 eyes randomly assigned to torsional (Infiniti Vision System; Alcon Laboratories, Fort Worth, TX), microburst with longitudinal (Infiniti), or microburst with longitudinal (Legacy Everest, Alcon Laboratories) ultrasound. Assessments included surgical clock time, fluid volume, and intraoperative complications, central corneal thickness on day 1 and months 1 and 3 postoperatively, and endothelial cell density at 3 months postoperatively. Comparisons among groups were conducted. Torsional ultrasound required significantly less surgical clock time and fluid volume than the other groups. There were no intraoperative complications. Change in central corneal thickness and endothelial cell loss was significantly lower in the torsional ultrasound group at all postoperative visits (P < .001, Kruskal-Wallis test) compared to microburst longitudinal ultrasound modalities. Torsional ultrasound demonstrated quantitatively superior intraoperative performance and showed less increase in corneal thickness and less endothelial cell loss compared to microburst longitudinal ultrasound.