With its microincision approach, bimanual phaco requires a more or less long and/or difficult learning curve depending on the surgeon’s personal ability to adjust to a new technique, new instrumentation and new machine parameters. Practitioners who are naturally ambidextrous will encounter practically no difficulties and therefore this chapter will not apply to them. Others may be able to benefit from some of the tips given here to facilitate the transition in a few easy steps. The goal is occasionally to practice bimanual phaco on the basis of well-mastered coaxial phaco procedures.
First stage
The smaller incisions limit operative manoeuvres for the better, i.e. reducing surgical trauma, but also for the worse, as they render certain interventional steps more difficult. The first step would then be to perform microincisions with 1.4-1.6 mm precalibrated knives instead of a 3.2 mm incision and the service incision customary in coaxial phaco. Practitioners should also remember to use the non-dominant hand.
Using a distal remote control forceps for the capsulorhexis comes naturally, and prudent hydrodissection completes the first phase of the transition. It will then suffice to enlarge one of the two incisions to 3.2 mm to continue in coaxial phaco mode.
At the end of the coaxial phaco procedure it is possible to try irrigation-aspiration of residual matter in bimanual mode. In addition to the fact that this strategy facilitates ablation of the matter at 12 o’clock, it is the most rewarding manoeuvre to learn the tactile sensations involved in bimanual phaco and the simultaneous use of both hands.
Second stage
Nuclear fracture using the Divide technique is more laborious when performed with a microincision of less than 1.5 mm than with a 3.2 mm incision, because of the then reduced mobility of the instruments. These reasons justify a new approach to nuclear fracture, adapted to the reduced size of the incisions, combining the already well-known advantages of Divide & Conquer and the efficacy of Chop to reduce ultrasound emission. This variant uses a Cobra probe with two posterior irrigation openings or an irrigation probe with two lateral ports, and does not require any complex training or expensive instruments. It is therefore suitable for all ophthalmologists wishing to carry out bimanual phaco cataract surgery. Once a deep medial groove has been cut into the nucleus, the latter is placed on the horizontal 3 o’clock – 9 o’clock meridian. The Cobra probe’s ladder-step end enables it to hook perpendicularly into the wound wall. Exercising traction towards 12 o’clock with the irrigation probe hooked into the upper edge of the groove, associated with a push towards 6 o’clock with the phaco probe on the opposite wound edge facilitates cracking. With this manoeuvre, the nucleus is split into two sections of equal size. The irrigation probe is placed on a heminucleus; its two infusion openings push back the posterior capsule and prevent the irrigation channel from becoming plugged up by cortical fragments. Each heminucleus is lifted up in turn and oriented towards the US probe, which emulsifies each in turn using more aspiration power.
Third stage
The learning curve in connection with the use of the Chop technique in bimanual phaco is less onerous for surgeons already using Chop in a coaxial approach. However, for most ophthalmologists performing cataract surgery using the Divide and Conquer technique, Chop requires a learning curve that is added on to that of bimanual phaco. The difficulties in synchronizing intracameral chopper manoeuvres with a simultaneous sculpting action of the ultrasound probe represent a hurdle for many practitioners in allowing themselves to be convinced by this technique, which is nonetheless very effective in bimanual phaco. It allows for shorter surgery times, ultrasound emission duration and the risk of corneal burns. It is best to begin Chop in a coaxial phaco approach and then learn to adapt the Chop strategy to the size and hardness of the nucleus. The first stage consists in selecting patients with a small nucleus of intermediate hardness. Patients with capsular pseudoexfoliation, a narrow anterior chamber, narrow pupils, poor pupillary reflex or enophthalmia should be avoided at this stage. Vertical Chop is undoubtedly easier to learn than Horizontal Chop, for which positioning the chopper on the nucleus equator and the subsequent displacement of the nucleus within the bag are the most delicate parts of the transition. It is thus preferable to begin by using the chopper merely as an irrigation instrument in the Divide and Conquer technique to become familiar with this intracameral tool. Then, proceed via the Stop and Chop technique before performing cracking without sculpture. Finally, Chop without sculpture requires more experience, in particular to keep the US probe positioned deeply within the nucleus and to optimise chopper orientation and direction of the chopper towards the US probe. Nuclear rotation movements, which prevent generation of sufficient compression power between the two instruments to fracture the nucleus, should be avoided during this manoeuvre. Mastering this technique will enable the surgeon to apply a bimanual phaco approach to all types of cataract and to enjoy 100% success in the conversion to this surgical technique.
