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Francisco Amparo, MD. * Luis F. Torres, MD, PhD. * J. Gerardo Garc ía-Aguirre , MD. *

Comparison of ultrasonic energy amount used in continuous vs pulsed mode in torsional micro-coaxial phacoemulsification in dense cataracts. Francisco Amparo, MD. * Luis F. Torres, MD, PhD. * J. Gerardo Garc ía-Aguirre , MD. *

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Francisco Amparo, MD. * Luis F. Torres, MD, PhD. * J. Gerardo Garc ía-Aguirre , MD. *

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  1. Comparison of ultrasonic energy amount used in continuous vs pulsed mode in torsional micro-coaxialphacoemulsification indense cataracts Francisco Amparo, MD.* Luis F. Torres, MD, PhD.* J. Gerardo García-Aguirre, MD.* Instituto de Oftalmología y Visión de Aguascalientes, Aguascalientes, México. * No financial interest 2008 ASCRS Annual Meeting, Chicago, IL

  2. IntroductionTorsional technology is a modality of phaco that offers advantages over other modalities. However, some changes and parameters to cataract approach with this modality are still emerging according to surgeons’ preferences. The idea to compare continuous torsional US vs pulsed torsional US was supported on the basis that pulsed modality generally represents less energy dispersion than continuous mode, specially in dense cataracts.

  3. Objective To compare the amount of ultrasonic energy in cumulative dispersed energy (CDE) units used to emulsify dense cataracts in two different modalities of torsional ultrasound, continuous and pulsed.

  4. Materials and methods In this prospective study patients were selected according to lens hardness using LOCS III classification. We included cataracts ranging from NO4/NC4 to NO5/NC5. Surgery was performed using stop and chop technique in all patients. Chylack LT, et al. The Lens Opacities Classification System III. The Longitudinal Study of Cataract Study Group. Arch Ophthalmol. 1993 Jun;111(6):831-6.

  5. Materials and methods • We randomly alternated the US modality for the central sculpting using continuous US and pulsed US. • Using the same US modality in first half than with central sculpting, and the other modality for the second half. • In one half we used custom pulsed torsional phaco (OZil, Infiniti Vision System, Alcon Labs), in the other half we used continuous torsional phaco (OZil, Infiniti Vision System, Alcon Labs). • US energy used was recorded at the end of central sculpting and after each half using cumulative dispersed energy (CDE) units. • All procedures were done through a 2 mm incision.

  6. Materials and methods Parameters used were: • For halves, bottle height 110 cm, vacuum 380 mmHg, aspiration flow 35 mmHg and dynamic rise 2. • For central, sculpting bottle height 110 cm, vacuum 20 mmHg, aspiration flow 30 mm Hg, rise 0. • Continuous US, 100 per cent linear longitudinal phaco combined with 100 per cent linear torsional phaco. • Pulsed US, 100 per cent linear longitudinal phaco with 30msec ON time, followed by 100 per cent linear torsional phaco with 300msec ON time and 150msec fixed OFF time.

  7. Results • For the final analysis 28 procedures were included. • Grooves: 14 using pulsed US and 14 using continuous US; halves: 28 using pulsed US and 28 with continuous US. • Clinical results were quite similar. Except for one, all patients had clear corneas and almost no inflammatory cells in anterior chamber the day after surgery. • One patient suffered important corneal edema around wound the day after surgery, but did not presented positive Seidel test and solved without complications after 1 week.

  8. Results Energy amount continuous vs pulsed - halves Energy amount continuous vs pulsed - groove P=0.605 p=0.605 p=0.872 CDE CDE US mode US mode

  9. Results Energy amount 1st vs 2nd half p=0.622 CDE 1st half 2nd half

  10. Results • There was not statistically significant difference between both modalities of US used in halves (p=0.605). • There was no statistically significant difference between both modalities of US used in central sculpting (p=0.872). • There was no statistically significant difference in relation with order of removal (p=0.622).

  11. Discussion • The results of the study showed that there are no difference between both US modalities used to remove halves or for the central sculpting; neither in relation with order of removal, discarding the possibility of second half being easier to remove than first. • In the case with corneal wound burn, US energy amount used was the higher of all cases studied. • Total CDE amount in this case were 45.90 units, and central sculpt was emulsified using pulsed mode. • We believe that this is related to a combination of dense cataract and a tight 2 mm incision.

  12. Conclusion • In our study, there was not difference in the amount of ultrasound energy needed, between continuous torsional and pulsed torsional modalities, to remove dense cataracts. • Clinical results between both modalities were quite similar. Even though personal opinion of the surgeon, regarding the performance of the procedure, that continuous mode is more comfortable during surgery, avoiding chattering and thus optimizing holding as the maximum benefit of torsional technology.

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