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Sleeveless bimanual phaco has several advantages
The technique can be performed using any phaco method and on any type of cataract.
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FIRENZE, Italy — Cataract surgery techniques have gradually evolved to allow increasingly greater reduction in incision size. For more than 200 years, the size of the incision remained essentially the same, changing only in shape and location, using extracapsular cataract extraction, intracapsular cataract extraction, and then again planned ECCE techniques. The first notable reduction in size was achieved in the 1990s with the introduction of the 5.5-mm capsular-bag IOL used in modern phacoemulsification. Several years passed before it was possible to progress to a 3.2-mm incision using foldable IOLs.
No doubt it can be stated that reduction of the incision size has always led to increased safety and speed, reduced astigmatism, faster patient rehabilitation and remarkably improved visual capacity. It is now possible to perform cataract surgery through an incision of only 1 mm. How has it been possible to go below the 3-mm limit? It is simple: by eliminating the phaco sleeve.
Maintaining infusion levels
Many would claim that the sleeve system guarantees the depth of the chamber and would ask how it is possible to maintain infusion levels without a sleeve. In our technique, the infusion enters laterally by means of a new instrument known as the infuser-manipulator. Inserted in the secondary side port, this instrument ensures the proper flow of infusion and makes it possible to maneuver the nucleus and manage its fragments.
In order to be manageable, the instrument had to be thin enough, but as a result of this design change, the flow of infusion was less than with the sleeve. Therefore, it was necessary to reduce the size of the tip to lower the amount of aspiration, thus maintaining the stability of the chamber. In this way, it was finally possible to move in the direction of a smaller incision.
Keeping it cool
However, the sleeve is also a cooling system. Many wondered what would happen in the tunnel without the protection of the silicone sheath and the infusion, and how burns would be prevented. It had previously been discovered that phaco could be performed without the sleeve. The 1970s phaco of Louis Girard, MD, was sleeveless. Surgeons saw how the crystalline lens could be removed by means of the pars plana using the fragmentation tips without a sleeve.
Nonetheless, the elimination of the cooling system was not seen as something to take light-heartedly. It could potentially incur a serious risk of tissue overheating and incision burns.
Thermographic analysis has demonstrated that sleeveless phaco generates less heat in the tunnel and inside the anterior chamber than traditional phaco with sleeve. The maximum temperature reached using the sleeve was 47.7 C° (117.9 °F), while with the sleeveless version temperatures never exceeded 28 °C (82.4 °F). Why was there such a difference? One would have expected to see acceptable temperatures — maybe even equal — but certainly not lower.
The tip moves at ultrasonic speed through materials of varying densities such as water, viscoelastic substances and the crystalline lens, creating friction. In immersing the tip in water (Figure 1), it can be observed that by inserting only the initial portion, a small ring will be created.
If, however, the tip is inserted as far as the cone, it will create a large, almost complete circle. Because the initial portion of the tip creates friction and friction heat, it follows that immersing it as far as the cone will generate much more heat than inserting the distal part only. The tip with sleeve acts as if it was immersed as far as the cone because of the water contained in the sleeve that is in contact with the anterior chamber (Figure 2). The same water that has been warmed then enters the front chamber.
Using the sleeveless technique with separate infusion counteracts the thermal effect of the cone (Figure 3). Further, it has been observed that the microtip is bathed and cooled by the cold saline infusion flowing through the secondary side port. With the microtip, the initial portion is even smaller and requires less ultrasound power, just as a thin scalpel needs less force to cut than a thick one. Although surgical times may be a bit longer, the technique has proven to be far less traumatic than standard sleeved phaco.
Dealing with unusual maneuvers
Eliminating the sleeve, using a microtip and operating with an infuser-manipulator through the secondary side port is not as simple as it seems. Bimanual sleeveless phaco is a totally new way to remove the crystalline lens, more so than it may seem at first. This new surgical technique needs to be fine-tuned so that every surgeon can perform it. The surgical instruments must also be adapted; special forceps are needed that can enter through the 1-mm incision to grasp the capsulorrhexis (Figure 4).
The best technique to crack the nucleus using a microtip is, in my opinion, mechanical fragmentation in quadrants. Chop technique becomes problematic because the small tip is unable to hold the fragments, as a small suction cup will grip with less force than a large one.
Bimanual technique can be performed using any type of phaco and on all types of cataract.
Although it is a new technique, most manufacturers have already begun to adapt their products to fulfill the new requirements. In particular, the microtip seems to enhance the performance of the venturi pump by minimizing negative effects. Compared to the peristaltic pump, it helps reduce surgical times.
The advantages of this technique are numerous: greater control over the anterior chamber even in the presence of a thrusting force, reduction in the use of viscoelastic, increased stability in a more protected chamber, greater manageability in the lower chamber, the possibility to work closer to the incision and better visibility when making incisions. In addition, at the end of the operation, only two openings have been made.
| Bimanual sleeveless technique gains popularity among surgeons | |
| I presented my bimanual sleeveless technique in a live-surgery session at the Italian Ophthalmic Association meeting in Rome in November 1999, performing phacoemulsification with a 0.69-mm microtip through a 1-mm incision. Ocular Surgery News documented the procedure in two articles, one in the U.S. edition (January 15, 2000, page 38) and one in the Europe/Asia-Pacific Edition, published in January 2000. Despite the interest raised, the technique has not found a following in the world of ophthalmology, nor did it after it was presented at other meetings during the same year, as I said at this year’s OSN Symposium on Cataract, Glaucoma and Refractive Surgery held in Florence. The fact that sleeveless phaco could be performed has been known for quite some time. Louis Girard, MD, suggested using sleeveless phaco in the 1970s, at virtually the dawn of phaco. Phaco through the pars plana is another example of sleeveless phaco that has been known for some time. For what reason, then, did no one attempt to practice it? Probably because everyone has been afraid of it of it and of the potential risk of tunnel burning, or at the least of an abnormal increase in heat, and consequent ocular damage. It was only at the end of 2002, after I performed a series of thermographic analyses in collaboration with the National Optical Institute of Florence, that the technique obtained large scale recognition. It was demonstrated that not only does sleeveless phaco not generate high temperatures, but rather it generates far lower temperatures than those produced by conventional phaco with sleeve. OSN published another article on this topic. In November 2001, at the Italian Ophthalmic Association meeting in Rome, I conducted a live-surgery session featuring two consecutive operations. One was performed with conventional phaco and one with the bimanual sleeveless technique, showing the thermographic measurements simultaneously on the screen. Thus everyone could observe firsthand that the temperatures produced using bimanual phaco were much colder than those generated using the conventional method. In the past few years, I have improved the technique, the surgical instruments and some parts of the phaco machine, namely the tip and the pump. I believe the success enjoyed by this method can be attributed partly to coverage by the ophthalmic press. However, this success is also thanks to the live-surgery sessions that have exposed the technique to the direct scrutiny and judgment of thousands of specialists, making it possible to examine both its complications and advantages with absolute clarity. |
For Your Information:References:
- Giuseppe Panzardi, MD, can be reached at Villa Donatello, Piazzale Donatello 14, 50132 Firenze, Italy; (39) 055-50975; fax: (39) 055-482-503; e-mail: kryq@libero.it.
- Panzardi G. Minimal stress technique offers advantages for cataract removal. Ocular Surgery News Europe/Asia-Pacific Ed. 2000;11:18-19.
- Cimberle M. Teflon phaco tip performs cataract surgery through 1-mm incision. Ocular Surgery News. 2000;18(2):38.
- Panzardi G. Sleeveless microtip keeps temperatures low and safe, thermographic study shows. Ocular Surgery News. 2002;20(10):36-37.
- Panzardi G. The use of thermography for temperature analysis during phacoemulsification. Buratto L, et al. Phacoemulsification Principles and Techniques, 2nd ed. Thorofare, N.J.: SLACK Incorporated; 2003:255-258.
- Panzardi G. Phacoemulsification with a microincision, microtip, and separate infusion. Buratto L, et al. Phacoemulsification Principles and Techniques, 2nd ed. Thorofare, N.J.: SLACK Incorporated; 2003:379-381.