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Bokkwan Jun MD, John P Berdahl MD, Terry Kim MD* Duke University Eye Center Durham, North Carolina

Thermal Study of Longitudinal and Torsional Ultrasound Phacoemulsification : Tracking the Temperature of Corneal Surface, Incision and Handpiece Bokkwan Jun MD, John P Berdahl MD, Terry Kim MD* Duke University Eye Center Durham, North Carolina

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Bokkwan Jun MD, John P Berdahl MD, Terry Kim MD* Duke University Eye Center Durham, North Carolina

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  1. Thermal Study of Longitudinal and Torsional Ultrasound Phacoemulsification: Tracking the Temperature of Corneal Surface, Incision and Handpiece Bokkwan Jun MD, John P Berdahl MD, Terry Kim MD* Duke University Eye Center Durham, North Carolina Supported by a research grant from Alcon, Inc., Consultant, Alcon, Inc.*

  2. Purpose • To investigate the change and difference in temperature at the corneal surface, incision, and handpiece • Two different modalities of ultrasound • Longitudinal • Torsional • Two different sizesof incision • Standard (2.75mm) • Microincisional (2.2mm) • To observe thermal effect on the wounds • Operating microscopy • Scanning electron microscopy (SEM)

  3. Methods • Prospective study • Twelve human cadaver eyes • Four groups of 3 eyes/group • Group 1: 2.75mm, 100% longitudinal • Group 2: 2.2mm, 100% longitudinal • Group 3: 2.75mm, 100% torsional • Group 4: 2.2mm, 100% torsional • System settings and accessories • Fluidics: Vacuum: 300mmHg, Aspiration: 12cc/min, Bottle height: 100cm and simulated On/Off occlusion approx. every 7 seconds • Phacoemulsification time: ~ 40 seconds with full power and instrument manipulation to simulate surgical use • Tip: Mini-Flared 30° Kelman tip • Sleeve: MicroSleeve for 2.75mm, UltraSleeve for 2.2mm

  4. Methods • Thermocamera (ThermaCAMTM, FLIR system, Danderyd, Sweden) • Thermal images were captured every 5 sec • The temperature of three areas was measured • Corneal surface • Incision • Handpiece • Operating microscopy • To observe wound burn with OR microscope (whitening and edema of the wound edge) • Scanning electron microscopy(SEM) 3 2 1

  5. Results • The average of maximum temperature of incision, handpiece and corneal surface in each group

  6. Results • Comparison of Thermal images at maximum temperature Group 1 (2.75mm, 100% longitudinal) Group 2 (2.2mm, 100% longitudinal) Group 1 (2.75mm, 100% torsional) Group 1 (2.2mm, 100% torsional)

  7. Results • Temperature changes of corneal surface, incision and hand piece Group 1 (2.75mm, 100% longitudinal) Group 2 (2.2mm, 100% longitudinal) Group 3 (2.75mm, 100% torsional) Group 4 (2.2mm, 100% torsional)

  8. Results • Comparison of incision temperature with 2.75mm and 2.2mm incision Group 1 (2.75mm, 100% longitudinal) vs Group 2 (2.2mm, 100% longitudinal) (p=0.002) Group 3 (2.75mm, 100% torsional) vs Group 4 (2.2mm, 100% torsional) (p<0.001)

  9. Results • Comparison of incision temperature between longitudinal and torsional groups Group 1 (2.75mm, 100% longitudinal) vs Group 3 (2.75mm, 100% torsional) (p<0.001) Group 2 (2.2mm, 100% longitudinal) vs Group 4 (2.2mm, 100% torsional) (p<0.001)

  10. Results • Operating microscopy • Group 1 and 2 (longitudinal US groups) • Wound burn (whitening and edema of the wound edge) was observed in 6/6 • Incision temperature was 43~45℃ when the first sign of wound burn was observed • Group 3 and 4 (torsional US groups) • No wound burn was evident in 0/6

  11. Results(SEM, endothelial view) • SEM images demonstrating wound gap of inner surface and partial loss of Descemet’s membrane Group 1 (2.75mm, 100% longitudinal) Group 2 (2.2mm, 100% longitudinal) Group 4 (2.2mm, 100% torsional) Group 3 (2.75mm, 100% torsional)

  12. Conclusions • Incision temperature • Can be influenced by ultrasound modality. • Was significantly lower in torsional ultrasound as compared to longitudinal ultrasound. • To a lesser extent, smaller incisions may also increase incision temperature, but not to a significant degree. • The combination of torsional ultrasound and small incisions • A safe way to decrease the risk of wound burn in patients with dense cataracts.

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