TILT AND TUMBLE

The tilt and tumble technique of phacoemulsification was first described by Dr Richard Lindstrom and is a type of supra-capsular phacoemulsification. It is a useful technique for soft cataracts and up to grade 2 nuclear sclerosis. However, it is not suitable for hard nuclei or mature cataracts. It involves using the pressure built up from a hydrodissection wave to prolapse a pole of the nucleus out of the capsular bag, following which the nucleus is emulsified in parts.

TECHNIQUE

A rhexis that is sized slightly larger than normal is important for this procedure. Ideally, it may be sized between 5-6mm but the denser the nucleus is, the larger the rhexis should be. Once the rhexis is completed, a hydrodissection cannula is used to tent up the capsular rim and a continuous fluid wave is gently irrigated into the sub-capsular space.

As the wave travels forwards, the pressure behind the nucleus increases and causes the opposite nuclear pole to tilt out of the rhexis rim. The anterior chamber (AC) is then filled with viscoelastic which is injected above the prolapsed nuclear pole and also under to prevent it from falling back into the capsular bag with the force of the irrigating fluid from the phaco probe. The phaco probe is then used to engage the nucleus and emulsify it. Once the prolapsed pole is emulsified, the other half of the nucleus is tumbled out of the bag and also emulsified in a similar manner. This is followed by routine cortex aspiration and intraocular lens (IOL) implantation.

ADVANTAGES

This is an easy technique to learn with a relatively short learning curve. It may be used in a variety of cases and is especially useful in managing soft cataracts as these are difficult to chop. Attempting to chop a soft cataract within the bag generally results in cheese-wiring of the nucleus. Endocapsular emulsification of a soft nucleus also has greater risk of posterior capsular rupture (PCR), as the phaco probe can cut through the soft cataract and rupture the posterior capsule before the surgeon has time to react. Bringing the soft cataract out into a supra-capsular plane allows it to be emulsified safely and being soft, the amount of energy used is less even if emulsified within the AC.

The hydroprolapse technique may also be used in patients with denser nuclei. The size of the rhexis, however, needs to be larger depending on the size and density of the nucleus. A minimum size of 5mm is generally adequate for a soft nucleus, but as the nuclear density increases the rhexis should be made correspondingly larger to avoid excessive build-up of pressure within the capsular bag behind the nucleus which can result in a capsular blow-out syndrome.

Soft nuclei may be hydrodelineated and completely prolapsed out into the AC, as the nucleus is small and can be aspirated easily with the phaco probe using vacuum alone without the need for excessive phaco energy. Larger nuclei may be chopped into two in a posterior chop technique. This is done by embedding the phaco probe into the prolapsed nuclear pole and pulling it further out of the bag. The chopper in the left hand is then held posterior to the prolapsed nucleus and used to divide the nucleus into two halves. These can then be rotated out of the bag and sequentially emulsified.

Hydrodelineation instead of a hydrodissection wave allows only the endonucleus to be prolapsed out and retains the epinuclear shell within the bag. This decreases the size of the nucleus and in turn the amount of phaco energy that is used within the AC. This technique may also be advantageous in subluxated cataracts where intracapsular chop and other manoeuvres such as nuclear rotation that place stress on the zonules are better avoided.

DISADVANTAGES

Dense nuclei may be too large to be prolapsed out of the rhexis and may therefore cause a capsular bag blow-out and consequent nucleus drop. Mature cataracts that fill the capsular bag completely may not move adequately within the bag with the fluid wave, and are also too large to prolapse out of the rhexis. Continuing the fluid wave can cause a capsular blow-out syndrome in these cases. Small rhexis may result in a similar blow-out because of excessive pressure behind the nucleus. Even a soft cataract may become difficult to prolapse out of an inadequately sized rhexis. The fluid wave that is seen travelling across the posterior pole of the nucleus gets released by the tilt and prolapse of one pole of the nucleus.

However, if the pole does not seem to prolapse out, excessive and repeated hydrodissection can cause capsular blow-out. In this case, the trapped fluid should be decompressed before attempting repeated hydroprocedures. Multi-quadrant hydrodissection may also help to free the nucleus up first, following which a hydroprolapse can be attempted.

Hydroprolapse may also not be preferred in patients with shallow AC or with borderline endothelial function, as emulsification releases phaco energy within the AC closer to the endothelium. If unavoidable, it is especially important to follow the classical tilt and tumble in these patients where only one pole is prolapsed and emulsified in the iris plane before tumbling the other half to emulsify as far from the endothelium as possible. In case the entire nucleus does prolapse out, it is easy to push one pole back into the capsular bag.

Hydrodissection and prolapse should never be attempted in a posterior polar cataract, though hydrodelineation may be carried out without risk of PCR. With a small pupil, even though the hydrowave tilts the nuclear pole out of the capsular bag, the iris may not allow it to come into the AC for phacoemulsification. Thus, it is more difficult and should be performed with caution.

CONCLUSION

This is a useful technique to learn, which is also easy and safe when performed in the correct manner.

Dr Soosan Jacob is Director and Chief of Dr Agarwal’s Refractive and Cornea Foundation at Dr Agarwal’s Eye Hospital, Chennai, India, and can be reached at: dr_soosanj@hotmail.com