Emulsification action of longitudinal and torsional ultrasound tips and the effect on treatment of the nucleus during phacoemulsification

Effect of IOP based infusion system with and without balanced phaco tip on cumulative dissipated energy and estimated fluid usage in comparison to gravity fed infusion in torsional phacoemulsification

Background

To evaluate the effect of three different combinations of tip designs and infusion systems in torsional phacoemulsification (INFINITI and CENTURION) in patients with cataract. According to the manufacturer, two unique improvements in the Centurion are: active fluid dynamic management system and use of an intrepid balanced tip. The study specifically aimed to evaluate the beneficial effects, if any, of change in tip design and infusion system individually and in combination on both per-operative parameters as well as endothelial health over 6 months.

Methods

One hundred and twenty six consenting patients of grade 4.0–6.9 senile cataract were randomized into three groups for phacoemulsification: Group A (n = 42): Gravity fed infusion system and 45⁰ Kelman miniflared ABS phaco tip; Group B (n = 42): intraocular pressure (IOP) based infusion system and 45⁰ Kelman miniflared ABS phaco tip; Group C (n = 42): IOP based infusion system and 45⁰ Intrepid balanced phaco tip. The cumulative dissipated energy (CDE), estimated fluid usage (EFU) and total aspiration time (TAT) were compared peroperatively. The endothelial parameters were followed up postoperatively for six months.

Results

The three arms were matched for age (p = 0.525), gender (p = 0.96) and grade of cataract (p = 0.177). Group C was associated with significant reductions in CDE (p = 0.001), EFU (p < 0.0005) as well as TAT (p = 0.001) in comparison to the other groups. All three groups had comparable baseline endothelial cell density (p = 0.876) and central corneal thickness (p = 0.561). On post-operative evaluation, although all groups were comparable till 3 months, by 6 months, the percentage losses in endothelial cell density were significantly lower in group C as compared to the other groups.

Conclusions

Use of an IOP based phacoemulsification system in association with use of the Intrepid balanced tip reduces the CDE, EFU and TAT in comparison to a gravity fed system with a mini flared tip or IOP based system with a mini flared tip while also providing better endothelial preservation thus favouring the use of an IOP fed system with a balanced tip.

Trial registration

Trial registration No.: CTRI/2016/06/007022.

Comparison of 45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification

AIM

To compare the intraoperative performance and postoperative outcome after microcoaxial torsional phacoemulsification using either a Kelman or balanced phaco tip.

METHODS

Cataracts were treated using 2.2 mm microcoaxial torsional phacoemulsification using either a 45-degree mini-flared Kelman(®) or a 45-degree Intrepid(®) Balanced phaco tip. Intraoperative measurements included total ultrasound (US) time, cumulative dissipated energy (CDE), torsional US time, and balanced salt solution (BSS) use. The central endothelial cell density (ECD) and central corneal thickness (CCT) were evaluated preoperatively and postoperatively 1, 7, and 30d after surgery using noncontact specular microscopy.

RESULTS

The 116 enrolled eyes (116 patients) were divided equally between the Kelman and balanced tip groups. Intraoperative measurements showed significantly less total US time, torsional US time, CDE, and BSS use in the balanced group than in Kelman group (P<0.05). The total US time, torsional US time, CDE, and BSS use were 17.45±14.53s, 16.63±13.97s, 6.38±5.26, and 48.21±17.21 mL in the Kelman group and 11.39 ± 9.60s, 10.90 ± 9.25s, 4.04 ± 3.42, and 41.36 ± 12.70 mL in the balanced group, respectively.

CONCLUSION

Torsional phacoemulsification performed with a balanced tip provided more effective lens removal with less total US time, torsional time, CDE, and BSS use, as well as similar changes in ECD with a Kelman tip in all cataract grades. This special designed phaco tip for torsional phacoemulsification provides an alternative phaco tip for many surgeons' preference with straight phaco tip.

Comparison of two different ultrasound methods of phacoemulsification

PURPOSE

To compare the safety and efficacy of microcoaxial phacoemulsification surgeries performed with the OZil Intelligent Phaco torsional mode (Alcon Laboratories, Inc., Fort Worth, USA) and combined torsional/longitudinal ultrasound mode using 45 degree aperture angled tips.

DESIGN

Prospective randomized clinical trial.

METHODS

setting: Maltepe University, Istanbul. patient population: Eighty eyes of 80 cataract patients were randomly assigned to 2.2 mm microcoaxial phacoemulsification using the OZil Intelligent Phaco torsional mode (Group 1) or combined torsional/longitudinal ultrasound mode (Group 2). observation procedure: Intraoperative fluid and energy usage and postoperative examinations were evaluated. main outcome measures: Ultrasound time, cumulative dissipated energy, longitudinal and torsional ultrasound amplitudes, mean operation time, mean volume of fluid used, and surgical complications.

RESULTS

Both groups included 40 eyes. Mean ultrasound time, cumulative dissipated energy, and longitudinal and torsional ultrasound amplitudes in Group 1 were 58.21±33.81 seconds, 7.74±6.23, 0.45±0.30, and 26.30±12.60%, respectively, and these parameters in Group 2 were 64.75±30.23 seconds, 12.61±6.21, 26.32±5.85, and 40.98±8.33%, respectively. Cumulative dissipated energy and longitudinal and torsional amplitudes were found to be significantly lower in Group 1 (P=.001, P<.001, P<.001). Mean volumes of fluid used in Groups 1 and 2 were 73.30±19.87 cc and 107.07±21.82 cc, respectively (P<.001).

CONCLUSION

With the aid of a 45 degree aperture angled tip, the OZil Intelligent Phaco torsional mode provided more effective lens removal than the combined torsional/longitudinal ultrasound mode, with a lower cumulative dissipated energy and volume of fluid used.

Effect of phaco tip diameter on efficiency and chatter

PURPOSE

To evaluate 3 phacoemulsification tips of different sizes and determine which size is most efficient in lens fragment removal using 3 ultrasound (US) approaches.

SETTING

John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental study.

METHODS

Porcine lens nuclei were formalin-soaked for 2 hours then divided into 2.0 mm cubes; 1.1 mm, 0.9 mm, and 0.7 mm phaco tips were used with torsional and micropulsed US. The 1.1 mm tips were unavailable for torsional US, so 0.9 mm and 0.7 mm tips were used. Efficiency (amount of time for lens removal) and chatter (number of lens-fragment repulsions from the tip) were determined.

RESULTS

The mean phacoemulsification efficiency was highest with the 0.9 mm tip for all US variations. There were statistically significant differences between the 0.9 mm and 0.7 mm tips with micropulsed US (0.8 seconds ± 0.29 [SD] versus 1.4 ± 0.93 seconds; P=.0112) and transversal US (0.8 ± 0.17 seconds versus 1.4 ± 0.89 seconds; P=.0065). There was no significant difference between 0.9 mm and 0.7 mm tips with torsional US or between the 1.1 mm and 0.9 mm tips with micropulsed or transversal US; however, trends were identical, with 0.9 mm tips performing better than 0.7 mm and 1.1 mm tips.

CONCLUSION

With all 3 systems, the 0.9 mm tip was most efficient, with the fewest outliers and smallest standard deviation.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Real-time intraoperative high-speed imaging during phacoemulsification

We describe the use of high-speed imaging during phacoemulsification in a clinical scenario. Images captured during surgery at high frame rates are converted into a slow-motion film to view and analyze various surgical steps. This technique highlights events that are not captured in a normal-speed video recording. It has obvious applications for understanding surgical techniques and technology.

Determining the local origin of hydroxyl radical generation during phacoemulsification

PURPOSE

To determine the local origin of hydroxyl radicals during phacoemulsification using an ultrasonic phacoemulsification device that includes longitudinal and torsional modalities.

SETTING

Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA.

DESIGN

Experimental study.

METHODS

Experiments were conducted using the Infiniti Vision System and Ozil handpiece. Hydroxyl radical concentrations during longitudinal and torsional phacoemulsification were quantitated as malondialdehyde (MDA) determined spectrophotometrically using the deoxyribose assay. The difference between the total concentration found in the aspirated solution at steady-state concentrations and the pre-aspirate levels deductively determined the concentration of MDA formed along the interior of the sonicating tip. The time to reach 50% of steady state as a function of reaction vessel volume was determined.

RESULTS

The mean maximum for torsional ultrasound at 100% amplitude was 7.70 nM ± 0.38 (SD), 91.1% of which was generated outside the tip. During longitudinal ultrasound at 100% power, MDA concentration in the aspirated solution was 29.5 ± 0.3 nM, 71.6% of which was generated outside the tip. The time (seconds) to reach 50% of maximum for longitudinal ultrasound using 5 mL, 10 mL, and 20 mL reaction vessels was 12.6 ± 1.5, 21.0 ± 1.5, and 25.3 ± 3.4, respectively.

CONCLUSION

Although a significantly greater proportion of the hydroxyl radicals generated during ultrasound modality were formed outside the phaco tip (91.1% torsional; 71.6% longitudinal), torsional ultrasound generated only about one-fourth the amount of MDA as longitudinal ultrasound in total and about one-third that generated outside the tip (7.02 nM versus 21.1 nM).

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.