Comparison of Continuous Versus Hyperpulse Ultrasound in Stop and Chop Phacoemulsification

1
Comparison of Continuous Versus Hyperpulse
Ultrasound in Stop and Chop Phacoemulsification

• Adolfo Peña Aceves M.D.
• Jorge L. Chin Wong M.D.
• Arturo Gallegos Valencia M.D.
• Cecilio F. Velasco Barona M.D.
• Anterior Segment Department
• Dr. Luis Sánchez Búlnes Hospital of the
  Association to Prevent Blindness in Mexico

No financial interest
2
Introduction

• Hyperpulses are a variation of pulsed
  ultrasound(US) in phacoemulsification.
• They are arbitrarily defined as 30 pulses per
  second (pps).
• The work cycle can be varied to lt50 on time.
• Some of the phaco mashines that have this
  technology
• Everest Legacy , and Infiniti Vision System
  (Alcon Laboratories, Inc.) Millennium
  microsurgical system (Bausch Lomb) Sovereign
  with WhiteStar technology (Advanced Medical
  Optics).

3
Purpose

• To determine the differences in US parameters and
  surgical technique between phacoemulsification
  using continuous and hyperpulse US when the
  central groove is carved.

4
Methods

• We used stop and chop technique in 36 eyes
  undergoing phacoemulsification with the Infiniti
  Vision System, measuring only the US and
  torsional energy used carving the central groove.
• We divided randomly 18 eyes for the use of
  continuous US and the other 18 for hyperpulses,
  all the other parameters were exactly the same,
  including NeoSoniX. All the surgeries were
  performed by 1 surgeon (APA).
• We used the lens opacities classification system
  III1, including cataracts with nuclear
  color/opalescence 3 and higher.
• For the analysis we used Mann-Whitneys U test.

1. Chylack LT, et al. The Lens Opacities
Classification System III. The Longitudinal Study
of Cataract Study Group.Arch Ophthalmol. 1993
Jun111(6)831-6.
5
Methods
Parameters measured
6
Parameters
Hyperpulses
Continuous US
7
Results
1
1. Chylack LT, et al. The Lens Opacities
Classification System III. The Longitudinal Study
of Cataract Study Group.Arch Ophthalmol. 1993
Jun111(6)831-6.
8
Results
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Discussion

• The reduction in US energy used in
  phacoemulsification has become a primary goal.
• Other energy sources have been proposed to
  displace US energy (Water, laser, sonic).2,3,4
• Hyperpulses/Micropulses have given US a new
  perspective.

2. Hoffman RS, y col. New phacoemulsification
technology. Curr Opin Ophthalmol 2005 16
38-43. 3. Fine IH, y col. Power modulations in
new phacoemulsification technology Improved
outcomes. J Cataract Refract Surg 2004 30
1014-19. 4. Fine IH y col. New phacoemulsification
technologies. J Cataract Refract Surg 2002 28
1054-60.
10
Discussion

• These studies show how hyperpulses/micropulses
  mantain the Phaco tip temperature below the
  tissue damage level (45) using different
  phacoemulsification mashines.

5. Soscia W, Howard JG, Olson RJ.
Microphacoemulsification with WhiteStar A
wound-temperature study. J Cataract Refract Surg
2002 281044-46. 6. Olson RJ, et al. White Star
technology. Curr Opin Ophthalmol 2003 14(1)
20-3 7. Braga-Mele R. Thermal effect of
microburst and hyperpuse settings during
sleeveless bimanual phacoemulsification with
advanced power modulations. J Cataract Refract
Surg 2006 32 639-42. 8. Osher RH, Injev VP.
Thermal study of bare tips with various system
parameters and incision sizes. J Cataract Refract
Surg 2006 32 867-72.
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Discussion

• Wether in coaxial, microcoaxial or biaxial
  phacoemulsification, Stop and Chop technique is
  still widely used in the world and it is an
  important technique in teaching
  centers.9,10,11,12
• The tendency in constantly reducing the size of
  corneal incisions makes the search for a
  reduction of US energy, thus a reduction in a
  possible burn injury to tissues, a logical path.
• We found that by using hyperpulses for the
  creation of the central groove, the mean phaco
  time and mean NeoSoniX time were reduced by 31
  and 39 respectively.

9. Mencucci R et al. Corneal endothelial damage
after cataract surgery Microincision versus
standard technique. J Cataract Refract
Surg. 2006 Aug32(8)1351-4. 10. Kurz S,
Krummenauer F, Gabriel P, Pfeiffer N, Dick HB.
Biaxial microincision versus coaxial
small-incision clear cornea cataract
surgery. Ophthalmology. 2006 Oct113(10)1818-26.
11. Pereira AC et al. Ultrasound energy and
endothelial cell loss with stop-and-chop and
nuclear preslice phacoemulsification. J
Cataract Refract Surg. 2006 Oct32(10)1661-6. 12.
Leaming DV. Practice styles and preferences of
ASCRS members-2003 survey. J Cataract Refract
Surg. 2004 Apr30(4)892-900.
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Conclusions

• Hyperpulses are a relatively new, save and
  reproducible technology for phacoemulsification.
• We found a decrease in ultrasound and torsional
  energy used in carving the central groove in Stop
  and Chop phacoemulsification with hyperpulses
  comparing it with continuous ultrasound.
• We think hyperpulses should be the ultrasound
  type of choice for creating the central groove in
  Stop and Chop phacoemulsification.