1.2 Transitioning to Bimanual MICS

18.Dosso AA, Cottet L, Burgener ND, Di Nardo S. Outcomes of coaxial microincision cataract surgery versus conventional coaxial cataract surgery. J Cataract Refract Surg 2008; 34:284–288

19.Osher RH. Micro-coaxial phacoemulsification. Part 2: clinical study. J Cataract Refract Surg 2007; 33:408–412

20.Cionni RJ. Torsional to longitudinal phacoemulsification comparison. In: American Society of Cataract and Refractive Surgery Annual Meeting, San Francisco, 2006

21.Miyoshi T, Yoshida H. From phaco-cutting to true phacoemulsification. VJCRS 2007; XXIII(4)

22.Fernandez de Castro LE, Sandoval HP, Vroman DT, Solomon KD. Fluid dynamics during phacoemulsification; fluid dispersion check model. In: American Society of Cataract and Refractive Surgery Annual Meeting, San Diego, 2007

23.Solomon K. Alcon CME Program, American Academy of Ophthalmology, San Fransisco, 2006

24.Osher J, Osher R. Understanding the dropped nucleus. Video J Cataract Refract Surg 2008; XXIV(4)

25.Boukhny M. Laboratory performance comparison of torsional and conventional longitudinal phacoemulsification. In: Annual Meeting of American Society of Cataract and Refractive Surgery, San Francisco, 17–22 March 2006

26.Allen D. Efficient surgery with a new torsional phaco mode. In: Annual Meeting of the American Society of Cataract and Refractive Surgery, San Francisco, 17–22 March 2006

27.Yoo S. Transitioning to torsional phaco emulsification. Cataract Refract Surg Today 2006; (supplement):7–8

28.Tjia KF. Efficiency of torsional versus longitudinal ultrasound. Cataract Refract Surg Today Europe 2008; May:33–34

29.Liu Y, Zeng M, Liu X, et al. Torsional mode versus conventional ultrasound mode phacoemulsification: randomized comparative clinical study. J Cataract Refract Surg 2007; 33:287–292

30.Johansson C. Quantitative comparison of longitudinal versus torsional phacoemulsification. In: European Society of Cataract and Refractive Surgeons Annual Meeting, London, 9–13 September 2006

31.Davison JA. Cumulative tip travel and implied followability of longitudinal and torsional phacoemulsification. J Cataract Refract Surg May 2008; 34:986–990

32.MacKool RJ. Lens removal/torsional phacoemulsification: advantages of nonlinear ultrasound. In: Annual ASCRS Symposium on Cataract, IOL, and Refractive Surgery, San Francisco, CA, 17–22 March 2006

33.Allen D. Cataract surgery evolves: new IOL implantation and fluidics technologies make transitioning to a microcoaxial technique easier and safer. Cataract Refract Surg Today 2007; (Supplement):3–5

34.Davison JA. Beginning micro-coaxial surgery. Eyeworld Supplement May 2008

35.Henderson B, Grimes K. Comparison of surgical efficiency using different ultrasound modulation on dense lenses and using varied angled phacoemulsification tips. ASCRS, San Diego, 2007

36.Osher RH, Marques FF, Marques D.M.V, Osher JM. Slow motion phacoemulsification technique. Tech Ophthalmol 1(2):73

37.Vaz F, Osher RH. Early uncorrected visual acuity with micro-coaxial phacoemulsification and torsional ultrasound: an independent study. In: Annual Meeting of the ASCRS, San Diego, 2007.

1.2 Transitioning to Bimanual MICS

Rosa Braga-Mele

Core Messages

ßTackle an easy case first and remember you can always default back to standard phacoemul-

sification.

ßA clear cornea trapezoidal incision is preferred so as to allow maneuverability within the wound

without stretching.

ßThe capsulorhexis forceps are advantageous as they create very little, if any, pressure on

the incision, but require a slight change in technique.

ßThere are multiple irrigating second instruments available. Try a few before committing

to any one.

ßMost of the currently available phaco platforms will support bimanual MICS without the

need to change current techniques.

1.2.1 Introduction

Microsurgery for phacoemulsification represents the next evolution in techniques for cataract surgery. When bimanual microsurgery was first introduced, the rally behind the push was that surgeons needed to learn smaller incision technique because IOLs that could be inserted into sub-2-mm incisions were on the horizon. Today, many small incision IOL’s are available around the world and the procedure is a reality. The procedure uses separate irrigation instruments and a sleeveless phaco tip to remove cataracts. Irrigation during phacoemulsification is provided through an irrigating chopper or manipulator instead of through the phacoemulsification handpiece. The surgery can be performed through incisions less than 1 mm and is associated with improved maneuverability, visualization, and less refractive error after surgery. Over the

R. Braga-Mele

University of Toronto, Toronto, ON, Canada

e-mail: RHOsher@CincinnatiEye.com

last few years, a number of advancements in phacoemulsification power modulations, understanding of fluid dynamics involved in bimanual phacoemulsification, and lenses that may be inserted through smaller incisions have brought renewed interest to bimanual phacoemulsification. Since those IOLs are now available, microphaco has caught on, mainly because a smaller incision for phaco induces less trauma in the eye, and the final incision, even when enlarged to insert the IOL, seems to seal better after the surgery is complete.

This chapter will focus on techniques and pearls to utilize during the transition from standard or coaxial microincisional surgery to bimanual microincisional cataract surgery (MICS).

1.2.2 Technique

Corneal incision: Two clear corneal trapezoidal incisions of 1.4–1.6 mm width or less are created in the inferotemporal and superotemporal quadrants using a metal or diamond blade, from a temporal approach. The external width of the incision is made slightly larger than both the phaco needle and the irrigating chopper to avoid tension on the incision and allow maneuverability within the wound, and thus have the advantage of a trapezoidal wound. The smaller internal wound minimizes egress of fluid around the instruments. It is important to know the gauge size of the phaco needle so that one can match the incision size and the irrigating chopper gauge.

Capsulorhexis: The capsulorhexis can be made using a 25 gauge bent cystotome needle or 23 gauge forceps that are specifically made for the procedure. This is one of the learning curves of the procedure. To use the capsulorhexis forceps, one must slightly modify the current technique. These forceps require more of a fine finger motion as opposed to a wrist motion. Also, it is a cross-action technique for opening and closing the forceps. However, in many ways the forceps are advantageous: they create very little pressure on the wound and control is superior.

Hydrodissection: It is important to get a good, complete hydrodissection. Because the wounds are small and tight, it is best to release some of the viscoelastic from the anterior chamber by burping the wound first.

Irrigating choppers: Multiple irrigating choppers or manipulators are currently available: those with a single-ended open-irrigating port; those with two sideirrigating ports; and those with an inferior irrigating port. Each has its advantages. With the single-ended instrument, one can inflate the chamber immediately upon entering the eye, and one can direct the fluid stream where one wants it to go. However, it can be difficult to learn to utilize. With the two side-irrigating ports, the fluidics remain relatively similar to coaxial phaco, but by positioning the chopper in certain directions, one can direct nuclear segment or inflate the capsular bag. The inferior port directs the fluid toward the posterior chamber keeping the capsule away from the phaco tip. There are many different types of irrigating handpieces available and today most deliver over 55–65 mL of fluid. My suggestion is to try different types and see which are best suited to your technique and comfort level.

Bimanual phacoemulsification: A 19 or 20 gauge irrigating chopper or manipulator is inserted into the inferotemporal stab incision using the left hand, and the phaco needle is inserted through the superotemporal incision with the right hand (or vice versa depending on the dominant hand). Note that this is counterintuitive to standard phaco where the phaco needle enters the eye first followed by the chopper. This is because the chopper now carries the fluid that helps maintain the chamber. Most of the currently available phaco units can be used to perform MICS because of the development of new phacoemulsification technologies and power modulations which allow the emulsification and fragmentation of nuclear material without the generation of significant thermal energy. Power modulations such as hyperpulse or microburst (with longer off than on times) are best utilized for this procedure. Techniques such as chop (horizontal or vertical), flip, or even divide and conquer can be utilized. One must either slightly lower the vacuum below settings used in conventional coaxial phacoemulsification, raise the bottle height, or pressurize the infusion. One can also use stable chamber tubing, which is more compliant with a small area of cylindrical filter mesh that increases resistance within the tubing and stabilizes the anterior chamber by essentially lowering the effective vacuum. The irrigating handpiece and phaco handpiece are used to engage the nucleus and fragment and emulsify it. The irrigating handpiece can be used to direct lens material to the phaco needle.

Irrigation and aspiration of cortex: This is perhaps an area where bimanual MICS is truly advantageous. Twenty gauge bimanual irrigating and aspirating instruments are each inserted into the eye. The aspirating probe is used to remove the cortex and if there is difficulty removing the subincisional cortex, the probes may be switched to reach the subincisional cortex.

IOL insertion: There are two methods commonly used for insertion of the IOL: either a 2.8 mm incision may be created between the two stab incisions or one of the stab incisions may be enlarged. Following the injection of the IOL into the capsular bag, residual viscoelastic is removed and all wounds are stromally hydrated. However, more recently, newer generation IOLs have become available that can easily go through a sub-2.0 mm incision.

1.2.3 Summary

Biaxial microincisional cataract surgery has its advantages. Irrigation through the side-port can help direct pieces of nuclear material towards the phaco tip. It minimizes the opposing forces of coaxial irrigation at pushing the nuclear material away. Slightly lower infusion pressure and the split of irrigation with the ability to control the fluid stream direction away from areas of zonular instability make it more beneficial in challenging cases. Also, if needed, nuclear material can be approached from both incision sites. With the availability of microincision IOLs, the procedure is more tightly controlled, the eye is more stable and less astigmatism is induced. This is the procedure of today and the future.

Take-Home Pearls

ßMicrosurgery for phacoemulsification represents the next evolution in techniques for cata-

ract surgery.

ßDo not change your technique or change too many parameters at one time.

ßStart slowly and pick the right case and patient.

ßBimanual MICS is safe and effective.

1.30.7 mm Microincision Cataract Surgery

Jorge L. Alió, Amar Agarwal, and

Pawel Klonowski

Core Messages

ßTo perform 0.7mm MICS (microincision cataract surgery) you need new 21 gauge instruments

ßTo achieve stable fluidics in the anterior chamber it is necessary to use pressurized infusion

ß0.7 mm MICS is the new limit of cataract surgery in terms of incision size

ß0.7mm MICS is possible in all cataract cases with today’s improvements in phaco technology

1.3.1 Sub 1 mm MICS: Why?

The natural trend of modern surgery is to minimize the physical aspects of intervention in the human body. During the last 40 years, cataract surgery has made the huge step from the 10–12 mm incision to the 0.7 mm incision. Not only the incision, but even the energy delivered, the surgical trauma and the time of the surgery have decreased. Nowadays, with millions of cataract surgeries performed annually around the world, the technique and outcome of surgery have become more efficient and predictable. Only minimal invasive surgery can improve the refractive result [1–3]. Many papers have confirmed the dependence between incision size and postoperative astigmatism, or corneal aberrations [4, 5]. This makes the surgery more efficient and faster. Reduction of incision size seems to be the trend in the normal evolution of surgery, and it will continue to be a challenge even in the future.

A. Agarwal ( )

Eye Research Centre & Dr. Agarwal’s Group of Eye Hospitals, 19 Cathedral Road, Chennai 600 086, India

email: dragarwal@vsnl.com

18.Dosso AA, Cottet L, Burgener ND, Di Nardo S. Outcomes of coaxial microincision cataract surgery versus conventional coaxial cataract surgery. J Cataract Refract Surg 2008; 34:284–288

19.Osher RH. Micro-coaxial phacoemulsification. Part 2: clinical study. J Cataract Refract Surg 2007; 33:408–412

20.Cionni RJ. Torsional to longitudinal phacoemulsification comparison. In: American Society of Cataract and Refractive Surgery Annual Meeting, San Francisco, 2006

21.Miyoshi T, Yoshida H. From phaco-cutting to true phacoemulsification. VJCRS 2007; XXIII(4)

22.Fernandez de Castro LE, Sandoval HP, Vroman DT, Solomon KD. Fluid dynamics during phacoemulsification; fluid dispersion check model. In: American Society of Cataract and Refractive Surgery Annual Meeting, San Diego, 2007

23.Solomon K. Alcon CME Program, American Academy of Ophthalmology, San Fransisco, 2006

24.Osher J, Osher R. Understanding the dropped nucleus. Video J Cataract Refract Surg 2008; XXIV(4)

25.Boukhny M. Laboratory performance comparison of torsional and conventional longitudinal phacoemulsification. In: Annual Meeting of American Society of Cataract and Refractive Surgery, San Francisco, 17–22 March 2006

26.Allen D. Efficient surgery with a new torsional phaco mode. In: Annual Meeting of the American Society of Cataract and Refractive Surgery, San Francisco, 17–22 March 2006

27.Yoo S. Transitioning to torsional phaco emulsification. Cataract Refract Surg Today 2006; (supplement):7–8

28.Tjia KF. Efficiency of torsional versus longitudinal ultrasound. Cataract Refract Surg Today Europe 2008; May:33–34

29.Liu Y, Zeng M, Liu X, et al. Torsional mode versus conventional ultrasound mode phacoemulsification: randomized comparative clinical study. J Cataract Refract Surg 2007; 33:287–292

30.Johansson C. Quantitative comparison of longitudinal versus torsional phacoemulsification. In: European Society of Cataract and Refractive Surgeons Annual Meeting, London, 9–13 September 2006

31.Davison JA. Cumulative tip travel and implied followability of longitudinal and torsional phacoemulsification. J Cataract Refract Surg May 2008; 34:986–990

32.MacKool RJ. Lens removal/torsional phacoemulsification: advantages of nonlinear ultrasound. In: Annual ASCRS Symposium on Cataract, IOL, and Refractive Surgery, San Francisco, CA, 17–22 March 2006

33.Allen D. Cataract surgery evolves: new IOL implantation and fluidics technologies make transitioning to a microcoaxial technique easier and safer. Cataract Refract Surg Today 2007; (Supplement):3–5

34.Davison JA. Beginning micro-coaxial surgery. Eyeworld Supplement May 2008

35.Henderson B, Grimes K. Comparison of surgical efficiency using different ultrasound modulation on dense lenses and using varied angled phacoemulsification tips. ASCRS, San Diego, 2007

36.Osher RH, Marques FF, Marques D.M.V, Osher JM. Slow motion phacoemulsification technique. Tech Ophthalmol 1(2):73

37.Vaz F, Osher RH. Early uncorrected visual acuity with micro-coaxial phacoemulsification and torsional ultrasound: an independent study. In: Annual Meeting of the ASCRS, San Diego, 2007.

1.2 Transitioning to Bimanual MICS

Rosa Braga-Mele

Core Messages

ßTackle an easy case first and remember you can always default back to standard phacoemul-

sification.

ßA clear cornea trapezoidal incision is preferred so as to allow maneuverability within the wound

without stretching.

ßThe capsulorhexis forceps are advantageous as they create very little, if any, pressure on

the incision, but require a slight change in technique.

ßThere are multiple irrigating second instruments available. Try a few before committing

to any one.

ßMost of the currently available phaco platforms will support bimanual MICS without the

need to change current techniques.

1.2.1 Introduction

Microsurgery for phacoemulsification represents the next evolution in techniques for cataract surgery. When bimanual microsurgery was first introduced, the rally behind the push was that surgeons needed to learn smaller incision technique because IOLs that could be inserted into sub-2-mm incisions were on the horizon. Today, many small incision IOL’s are available around the world and the procedure is a reality. The procedure uses separate irrigation instruments and a sleeveless phaco tip to remove cataracts. Irrigation during phacoemulsification is provided through an irrigating chopper or manipulator instead of through the phacoemulsification handpiece. The surgery can be performed through incisions less than 1 mm and is associated with improved maneuverability, visualization, and less refractive error after surgery. Over the

R. Braga-Mele

University of Toronto, Toronto, ON, Canada

e-mail: RHOsher@CincinnatiEye.com

last few years, a number of advancements in phacoemulsification power modulations, understanding of fluid dynamics involved in bimanual phacoemulsification, and lenses that may be inserted through smaller incisions have brought renewed interest to bimanual phacoemulsification. Since those IOLs are now available, microphaco has caught on, mainly because a smaller incision for phaco induces less trauma in the eye, and the final incision, even when enlarged to insert the IOL, seems to seal better after the surgery is complete.

This chapter will focus on techniques and pearls to utilize during the transition from standard or coaxial microincisional surgery to bimanual microincisional cataract surgery (MICS).

1.2.2 Technique

Corneal incision: Two clear corneal trapezoidal incisions of 1.4–1.6 mm width or less are created in the inferotemporal and superotemporal quadrants using a metal or diamond blade, from a temporal approach. The external width of the incision is made slightly larger than both the phaco needle and the irrigating chopper to avoid tension on the incision and allow maneuverability within the wound, and thus have the advantage of a trapezoidal wound. The smaller internal wound minimizes egress of fluid around the instruments. It is important to know the gauge size of the phaco needle so that one can match the incision size and the irrigating chopper gauge.

Capsulorhexis: The capsulorhexis can be made using a 25 gauge bent cystotome needle or 23 gauge forceps that are specifically made for the procedure. This is one of the learning curves of the procedure. To use the capsulorhexis forceps, one must slightly modify the current technique. These forceps require more of a fine finger motion as opposed to a wrist motion. Also, it is a cross-action technique for opening and closing the forceps. However, in many ways the forceps are advantageous: they create very little pressure on the wound and control is superior.

Hydrodissection: It is important to get a good, complete hydrodissection. Because the wounds are small and tight, it is best to release some of the viscoelastic from the anterior chamber by burping the wound first.

Irrigating choppers: Multiple irrigating choppers or manipulators are currently available: those with a single-ended open-irrigating port; those with two sideirrigating ports; and those with an inferior irrigating port. Each has its advantages. With the single-ended instrument, one can inflate the chamber immediately upon entering the eye, and one can direct the fluid stream where one wants it to go. However, it can be difficult to learn to utilize. With the two side-irrigating ports, the fluidics remain relatively similar to coaxial phaco, but by positioning the chopper in certain directions, one can direct nuclear segment or inflate the capsular bag. The inferior port directs the fluid toward the posterior chamber keeping the capsule away from the phaco tip. There are many different types of irrigating handpieces available and today most deliver over 55–65 mL of fluid. My suggestion is to try different types and see which are best suited to your technique and comfort level.

Bimanual phacoemulsification: A 19 or 20 gauge irrigating chopper or manipulator is inserted into the inferotemporal stab incision using the left hand, and the phaco needle is inserted through the superotemporal incision with the right hand (or vice versa depending on the dominant hand). Note that this is counterintuitive to standard phaco where the phaco needle enters the eye first followed by the chopper. This is because the chopper now carries the fluid that helps maintain the chamber. Most of the currently available phaco units can be used to perform MICS because of the development of new phacoemulsification technologies and power modulations which allow the emulsification and fragmentation of nuclear material without the generation of significant thermal energy. Power modulations such as hyperpulse or microburst (with longer off than on times) are best utilized for this procedure. Techniques such as chop (horizontal or vertical), flip, or even divide and conquer can be utilized. One must either slightly lower the vacuum below settings used in conventional coaxial phacoemulsification, raise the bottle height, or pressurize the infusion. One can also use stable chamber tubing, which is more compliant with a small area of cylindrical filter mesh that increases resistance within the tubing and stabilizes the anterior chamber by essentially lowering the effective vacuum. The irrigating handpiece and phaco handpiece are used to engage the nucleus and fragment and emulsify it. The irrigating handpiece can be used to direct lens material to the phaco needle.

Irrigation and aspiration of cortex: This is perhaps an area where bimanual MICS is truly advantageous. Twenty gauge bimanual irrigating and aspirating instruments are each inserted into the eye. The aspirating probe is used to remove the cortex and if there is difficulty removing the subincisional cortex, the probes may be switched to reach the subincisional cortex.

IOL insertion: There are two methods commonly used for insertion of the IOL: either a 2.8 mm incision may be created between the two stab incisions or one of the stab incisions may be enlarged. Following the injection of the IOL into the capsular bag, residual viscoelastic is removed and all wounds are stromally hydrated. However, more recently, newer generation IOLs have become available that can easily go through a sub-2.0 mm incision.

1.2.3 Summary

Biaxial microincisional cataract surgery has its advantages. Irrigation through the side-port can help direct pieces of nuclear material towards the phaco tip. It minimizes the opposing forces of coaxial irrigation at pushing the nuclear material away. Slightly lower infusion pressure and the split of irrigation with the ability to control the fluid stream direction away from areas of zonular instability make it more beneficial in challenging cases. Also, if needed, nuclear material can be approached from both incision sites. With the availability of microincision IOLs, the procedure is more tightly controlled, the eye is more stable and less astigmatism is induced. This is the procedure of today and the future.

Take-Home Pearls

ßMicrosurgery for phacoemulsification represents the next evolution in techniques for cata-

ract surgery.

ßDo not change your technique or change too many parameters at one time.

ßStart slowly and pick the right case and patient.

ßBimanual MICS is safe and effective.

1.30.7 mm Microincision Cataract Surgery

Jorge L. Alió, Amar Agarwal, and

Pawel Klonowski

Core Messages

ßTo perform 0.7mm MICS (microincision cataract surgery) you need new 21 gauge instruments

ßTo achieve stable fluidics in the anterior chamber it is necessary to use pressurized infusion

ß0.7 mm MICS is the new limit of cataract surgery in terms of incision size

ß0.7mm MICS is possible in all cataract cases with today’s improvements in phaco technology

1.3.1 Sub 1 mm MICS: Why?

The natural trend of modern surgery is to minimize the physical aspects of intervention in the human body. During the last 40 years, cataract surgery has made the huge step from the 10–12 mm incision to the 0.7 mm incision. Not only the incision, but even the energy delivered, the surgical trauma and the time of the surgery have decreased. Nowadays, with millions of cataract surgeries performed annually around the world, the technique and outcome of surgery have become more efficient and predictable. Only minimal invasive surgery can improve the refractive result [1–3]. Many papers have confirmed the dependence between incision size and postoperative astigmatism, or corneal aberrations [4, 5]. This makes the surgery more efficient and faster. Reduction of incision size seems to be the trend in the normal evolution of surgery, and it will continue to be a challenge even in the future.

A. Agarwal ( )

Eye Research Centre & Dr. Agarwal’s Group of Eye Hospitals, 19 Cathedral Road, Chennai 600 086, India

email: dragarwal@vsnl.com