An American Society of Cataract and Refractive Surgery (ASCRS) survey recently showed an increased interest (ie, 24% of responders) in chopping techniques. Divide-and-conquer continues to be preferred, with 54% of those surveyed using this technique.1
In effective phacoemulsification chop techniques, the phaco tip firmly holds and stabilizes the nucleus, while the chopper cuts and separates the lens fragments. Mechanical energy is used to divide the lens into smaller fragments for easier manipulation.
Phaco chop is more difficult to learn compared with divide and conquer, as it requires skill in both hands. Stabilizing the nucleus to perform chopping maneuvers may be difficult, especially in the vertical chop. Horizontal chop—if not performed adequately—risks damaging the capsulorrhexis.2 Although chopping techniques are more effective and save ultrasonic energy, they may have a longer learning curve, causing some surgeons to give up before managing them.
Another option to divide the nucleus is with prechopping techniques.3-5 Specially designed forceps divide the nucleus, without the need of sculpting or holding it with the phaco tip. The adequate prechopper model depends on the hardness of the nuclei. We have been using prechoppers for several years, and we have found them to be a good option for dividing the nucleus. Nevertheless, this instrument presents with a learning curve.
BRUNESCENT CATARACTS A CHALLENGE
Very hard brunescent nuclei are difficult to dissect with chopping techniques, because tough elastic strands (ie, possessing a leathery quality) connect the posterior surface and span across the fragments. These strands pose a challenge when attempting to completely divide the nuclei.
Modern phacoemulsification techniques require nuclear prefracture for a more efficient fragment emulsification. Looking for an alternative to phaco chop or conventional prechopping, Luis Escaf, MD, designed an ultrasonic blade (Ultrachopper; manufacturer and author have signed a confidentiality agreement) that allows the division of nuclei of all hardnesses with an amazing ease and extreme security. The Ultrachopper is an ultrasonic knife that delicately cuts nuclear substances with control. Dr. Escaf came up with his idea while using an electric knife at home.
The Ultrachopper is similar to any phaco needle but with a flattened and tilted end. Two aspiration ports are located in the superior portion above the flattened segment. This new ultrasonic blade may be used with any phaco system by connecting it to the handpiece; it can quickly be interchanged with another phaco needle if necessary.
This device combines the mechanical force of the blade displacement with ultrasound energy, making it effective to cut lens fibers. The various blade tips—designed according to nucleus hardness—are flattened and curved downward (Figure 1). Dividing the nucleus with the Ultrachopper is simpler than with other prefracture maneuvers.
ULTRACHOPPER: SAFE AND EFFECTIVE
The blade design allows for cutting the cataract without touching the iris, capsulorrhexis, or posterior capsule. Another advantage is that the blade may divide the nucleus into unlimited parts (Figures 2 and 3),4-8 without producing significant stress on the capsular bag and zonules. This simplifies the emulsifications of the fragments, especially in hard cataracts.
The Ultrachopper does not pose a risk to the posterior capsule, because the length of the blade reaches around 30% to 50% of the nucleus thickness, even in the mid-periphery of the cataractous lens (Figures 4 through 6).
The depth of the cut is directly related to the excursion of the blade. This depends upon ultrasound power, which can be adjusted according to the degree of the cataract.
SURGICAL TECHNIQUES
This ultrasonic blade may be used with a sleeve (ie, for standard coaxial phaco) or without a sleeve (ie, for microincisional phaco). Dr. Escaf has introduced two terms:
1. Ultraphaco: when the surgeon uses either conventional coaxial phaco or coaxial microphaco to emulsify the cataract fragments after cracking the nucleus with the Ulrachopper.
2. Ultraqual: if AquaLase (Alcon Laboratories, Inc., Fort Worth, Texas) is used to retrieve the fragments.
SURGICAL STEPS
Following the rhexis, the surgeon applies the blade to the nuclear material and presses the foot pedal to position three. The blade cuts and separates the nucleus. In case of very hard nuclei with no cortex, we prefer to first make the cut with the Ultrachopper and then proceed with hydrodissection afterward. This avoids posterior capsular rupture, due to increased pressure in the bag. In soft cataract cases, the flattened curve tip of the Ultrachopper is placed in contact with the proximal portion of the nucleus, and the pedal is placed in position three. The Ultrachopper is moved toward the distal edge of the rhexis, and a clear cut is made in the lens.
Using the Ultrachopper Set (Katena Products, Inc., Denville, New Jersey) (Figure 7), also designed by Dr. Escaf, we perform a light centrifuge pressure in the line of fracture, separating the nucleus into two halves. For separation of harder cataracts, the device may be passed along the same path two or three times. Often, we use a nucleus sustainer (Figures 8 and 9) to exert counterpressure on the motion of the Ultrachopper. This is not necessary with the OZil system (Alcon Laboratories, Inc.), because the tip's 5º horizontal displacement makes the Ultrachopper even more effective (Figure 10). This produces a cutting and separating effect (100 µm) (Figure 11).
The nucleus sustainer, introduced by the auxiliary incision, is placed in contact with the nuclear material and is slid underneath the edge of the rhexis, guaranteeing that it will never be placed above the anterior capsule. Sometimes, it is easy to see how the sustainer rejects the edge of the rhexis as it enters the bag. Once inside, the sustainer is placed at the equator of the nucleus, which holds it firmly. Then, the pedal is placed in position three, and the Ulthachopper is placed in the proximal area of the nucleus. While the Ultrachopper slides, the sustainer exerts counterpressure. If the inital groove does not have an adequate depth, the Ultrachopper may slide through it again, either forward or backward.
We now use the Ultrachopper in 100% of cases, and Dr. Escaf has performed more than 1,600 surgeries using either Ultraphaco or Ultraqual in all types of nuclei. Ninety percent of cases are completed with the Ultraphaco technique, and the remaining cases are completed using the Ultraqual technique.
SHORT LEARNING CURVE
The learning curve with the Ultrachopper is minimal. We have personally experienced this learning curve, and following the first case we could use the device comfortably, without complications. If a surgeon is familiar with chopping techniques, there will be a one-case learning curve. During the first procedure with the Ultrachopper, we noticed an improvement in our operative results.
The Ultrachopper has changed the scope of the surgeon in front of a hard nucleus, because it meets the challenge of this procedure. We believe that the Ultrachopper will assist in phacoemulsification of hard cataracts, and will change the way we teach phacoemulsification to our residents. Perhaps, one day, it will not be necessary that they learn another technique before entering the realm of the Ultrachopper.
The Ultrachopper is projected to be on the market by mid-2008; US and international patents pending.
Luis J. Escaf, MD, practices at the Clinica Oftalmologica del Caribe, in Colombia. Dr. Escaf states that he has signed a confidentiality agreement with a company to manufacturer the Ultrachopper. He may be reached at tel: +57 5 357 3171; fax +57 5 357 3169; or oftalmocaribe.le@gmail.com.
Virgilio Galvis, MD, practices at the Centro Oftalmológico Virgilio Galvis, Centro Médico Ardila Lülle, Urbanización El Bosque, in Floridablanca, Colombia. He may be reached at tel: +57 7 639 2929; fax: +57 7 639 2626; or virgiliogalvis@gmail.com.
Alejandro Tello, MD, practices at the Centro Oftalmológico Virgilio Galvis, Centro Médico Ardila Lülle, Urbanización El Bosque, in Floridablanca, Colombia. Dr. Galvis may be reached at tel: +57 7 639 2929; fax: +57 7 639 2626; or virgiliogalvis@gmail.com.
Across the Pond | Mar 2007
Ultrachopper: A New Way to Divide the Nucleus
This ultrasonic blade is similar to a phaco needle, but the end is flat and tilted.
Luis J. Escaf, MD; Virgilio Galvis, MD; and Alejandro Tello, MD
