Ординатура / Офтальмология / Английские материалы / Bimanual Phaco Mastering the Phakonit MICS Technique_Agarwal_2004

Chapter

6

INSTRUMENTS FOR BIMANUAL PHACO

Amar Agarwal, MS, FRCS, FRCOphth

HISTORY

Bimanual phaco (or Phakonit) was basically developed to reduce the size of the incision.1-5 This was done by removing the sleeve from the phaco needle. In order to introduce fluid into the eye during the procedure, in the beginning in 1998, we took a needle and bent it like an irrigating chopper and started doing bimanual phaco with it. When it succeeded, we realized the potential of this technique. With time, we have devised various instruments working with many companies around the world to make bimanual phaco an easier and safer technique.

INSTRUMENTS TO CREATE THE INCISION

One of the main problems in bimanual phaco was creating the temporal clear corneal incision. When we started the technique, there were no knives for the surgery, so we used a microvitreoretinal (MVR) blade for the purpose. Now many special bimanual phaco knives are available on the market (Figure 6-1).

Note in Figure 6-1 the left hand holds a globe stabilization rod (Geuder, Heidelberg, Germany). This helps to stabilize the eye while creating the clear corneal incision. The special knife is held in the dominant hand. This knife has been designed by Mateen Amin. It creates an incision of either sub-1.0 mm or 1.2 mm depending on which size knife is chosen by the surgeon. If one is using a sub-1.0 mm knife then one should use a 21-gauge irrigating chopper and a 0.8-mm phaco needle.

Knives for bimanual phaco can be either sapphire (Figure 6-2) or stainless steel. The Sapphire Phakonit knife has been made by Huco (Switzerland). It creates a very good 1.2 mm valve. A stainless steel blade has been made by Microsurgical Technology (MST, Redmond, Wash). This creates an incision of 1.2 to 1.4 mm (Figure 6-3). One of the key issues in bimanual phaco is to have a very good valve. If the valve is bad, there will be iris prolapse and the advantage of the microincision in bimanual phaco will be negated.

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Figure 6-1. Clear corneal incision made with a special knife (MST, Redmond, Wash). Note the left hand has a globe stabilization rod to stabilize the eye (Geuder, Heidelberg Germany). This knife can create an incision from sub-1.1 mm to 1.2 mm.

Figure 6-2. Agarwal sapphire Phakonit knife made by Huco (Switzerland).

Figure 6-3. Incision created by the stainless steel knife by MST (Redmond, Wash). This creates an incision of 1.2 to 1.4 mm. Note the globe stabilization rod in the left hand used to stabilize the eye.

Another difficulty faced in bimanual phaco is that we have two incisions of 1.0 mm. In phaco, one does not need to be as careful while creating the side port incision. However, in bimanual phaco one should be very careful even while creating the side port incision to avoid iris prolapse that can occur through the incision if the valve is not well made.

Figure 6-4A. Phakonit instrument set from Geuder (Heidelberg, Germany).

GLOBE STABILIZATION ROD

AND NUCLEUS MANIPULATOR

This is an extremely important tool. One end of the rod has a blunt tip which helps to stabilize the eye (see Figures 6-1 and 6-3). The other end of the rod has a fork or a Y (Figure 6-4A). This helps to rotate the nucleus after hydrodissection. This can also be used for retracting the iris in small pupils. Finally, the fork helps to also implant the IOL as it can tuck the IOL into the capsular bag. This instrument is available from Geuder. If one is operating under no anesthesia or topical anesthesia, the globe stabilization rod is very helpful in stabilizing the eye especially if the patient is uncooperative. Figure 6-4B shows the Megatron S3 Phaco/Phakonit machine from Geuder.

RHEXIS INSTRUMENTS

Rhexis can be done with a needle (Figure 6-5). The advantage of this is that every time one can use a new needle and bend it like a cystotome to create the rhexis. One should use a 26-gauge needle connected to a syringe with viscoelastic. If the viscoelastic leaks out from the wound, the viscoelastic can be injected inside the eye. One should use the globe stabilization rod in the nondominant hand while performing the rhexis.

Microsurgical Technology has designed an excellent rhexis forceps for bimanual phaco (Figure 6-6A). This goes through a 1.0-mm incision. Those comfortable with a forceps in phaco can use this special forceps in bimanual (Figure 6-6B). Designed by Larry Laks from the United States, this forceps works very well. One problem in bimanual phaco is that those who are comfortable with a forceps in phaco find it difficult to convert to bimanual, as one has to shift to a needle for rhexis. The advantages of the MST forceps are:

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Figure 6-4B. Megatron S3 Phaco/Phakonit Machine from Geuder (Heidelberg, Germany).

Figure 6-5. Rhexis done with a needle.

Figure 6-6A. Rhexis forceps from MST (Redmond, Wash).

Figure 6-6B. MST Rhexis forceps used to perform the rhexis in a mature cataract. Note the Trypan Blue staining the anterior capsule.

Figure 6-7. Two designs of Agarwal irrigating choppers. The one on the left has an end opening for fluid. The one on the right has two openings on the sides.

•The removable head enables easy upgrades.

•There are flat areas in the forceps which are located in the areas where the surgeons fingers should be present. This helps easy handling of the forceps.

•The innovative fine tip lets one hold the tissue easily.

IRRIGATING CHOPPERS

After enlarging the side-port, a 20-gauge irrigating chopper connected to the infusion line of the phaco machine is introduced with foot pedal on position 1. There are various irrigating choppers. In Figure 6-7, you will notice two designs of irrigating choppers which we have designed. On the left is the Agarwal irrigating chopper made by the MST company, which is incorporated in their Duet system. The irrigating chopper on the right is made by Geuder. Notice in the right figure the opening for the fluid is end opening, whereas the one on the left has two openings in the side. Depending on the convenience of the surgeon, the surgeon can decide which design of irrigating chopper they would like to use.

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Figure 6-8. Bimanual phaco done. Notice the irrigating chopper with an end opening (courtesy of Larry Laks, MST, USA).

Figure 6-9. Agarwal Phakonit irrigating chopper (MST, Redmond, Wash) and Phako probe without the sleeve inside the eye. This irrigating chopper has a sharp tip and a cutting edge that helps in “karate” chopping or quick chopping.

The phaco probe is connected to the aspiration line and the phaco tip (without an infusion sleeve) is introduced through the clear corneal incision (Figures 6-8 and 6-9). The irrigating chopper we designed is basically a sharp chopper with a sharp cutting edge and helps in karate chopping or quick chopping. It can chop any type of cataract including hard cataracts.

Microsurgical Technology’s Duet system has two handles (Figures 6-10 and 6-11). One handle is for irrigation and the other for aspiration. Various irrigating choppers of various surgeons can be interchanged with these handles (Figure 6-12). We have also designed a sharp irrigating chopper for Katena (Denville, NJ).

AIR PUMP

One of the real concerns in bimanual phaco when it was first started was the problem of destabilization of the anterior chamber during surgery.3,4 This was solved to a certain extent by using an 18-gauge irrigating chopper. A development made by Sunita Agarwal was to use an air pump that injects air into the infusion bottle (see Chapter 7). This pushes in more fluid into the eye through the irrigating chopper and also prevents

Figure 6-10. Duet handles (MST, Redmond, Wash).

Figure 6-11. Duet handles from MST. The advantage of these handles is that one can change the irrigating chopper tips.

Figure 6-12. Various irrigating chopper tips designed by various surgeons. These can be fixed onto the Duet handles.

surge. Thus, we were not only able to use a 20or 21-gauge irrigating chopper but also to solve the problem of destabilization of the anterior chamber during surgery. This increases the steady-state pressure of the eye making the anterior chamber deep and well maintained during the entire procedure. This is very essential in bimanual phaco.

BIMANUAL IRRIGATION ASPIRATION SYSTEM

Bimanual irrigation aspiration is then done with the bimanual irrigation aspiration instruments (Figures 6-13 and 6-14). These instruments are designed by Microsurgical Technology and Geuder. MST also designed a soft tip I/A that is very safe for the posterior capsule (Figures 6-15 and 6-16).

MEGATRON S3 MACHINE

This machine from Geuder (see Figure 6-4B) has all the features for performing a phaco or a bimanual phaco procedure.

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Figure 6-13. Bimanual irrigation started using the Duet system.

Figure 6-14. Bimanual irrigation aspiration completed.

Figure 6-15. Soft tip I/A from

MST (courtesy of Larry Laks,

MST, Redmond, Wash).

Figure 6-16. Soft tip

I/A set from MST.

SUMMARY

With improvements in technology, newer and better instruments will soon come out and make the process of bimanual phaco easier.

KEY POINTS

In phaco, one does not need to be very careful while creating the side-port incision, whereas in bimanual phaco, one should be very careful—even while creating the side-port incision—as there can be iris prolapse through that incision if the valve is not good.

The nondominant hand should hold a globe stabilization rod to stabilize the eye while creating the clear corneal incision.

One problem in bimanual phaco is that those who are comfortable with a forceps in phaco find it difficult to convert to bimanual phaco as one has to shift to a needle for rhexis.

The Agarwal irrigating chopper is basically a sharp chopper which has a sharp cutting edge and helps in karate chopping or quick chopping. It can chop any type of cataract including hard cataracts.

The air pump or some sort of gas forced infusion system is mandatory in bimanual phaco.

REFERENCES

1.Agarwal S, Agarwal S, Sachdev MS, Mehta KR, Fine IH, Agarwal A. Phacoemulsification, Laser Cataract Surgery, and Foldable IOLs. New Delhi, India: Jaypee Brothers; 1998.

2.Boyd BF, Agarwal S, Agarwal A, Agarwal A. LASIK and Beyond LASIK. Panama: Highlights of Ophthalmology; 2000.

3.Fishkind WJ. The phaco machine: how and why it acts and reacts? In: Agarwal A. Textbook of Ophthalmology. Vols 1 through 4. New Delhi, India: Jaypee Brothers: New Delhi; 2000.

4.Seibel SB. The fluidics and physics of phaco. In: Agarwal S, et al. Phacoemulsification, Laser Cataract Surgery and Foldable IOLs. 2nd ed. New Delhi, India: Jaypee Brothers; 2000; 45-54.

5.Agarwal, et al. No anesthesia cataract surgery with karate chop. In: Agarwal S, et al.

Phacoemulsification, Laser Cataract Surgery and Foldable IOLs. New Delhi, India: Jaypee Brothers; 1998.