Fig. 1
Prolapsed lateral pole of the nucleus
Viscoprolapse
One pole of nucleus can be prolapsed by injecting 2 % hydroxypropyl methylcellulose (HPMC) under the capsulorrhexis near the capsular fornix. The technique is similar to hydroprolapse. This technique is also useful for soft cataracts. Prerequisite is adequate pupillary dilatation and adequate size of capsulorrhexis.
Prolapsing with Sinskey Hook
This technique is suitable for moderate to hard nucleus. This can be performed with a single Sinskey hook or with two hooks bimanually.
Single Hook Method
After thorough hydrodissection and hydrodelineation, the AC is inflated with a dispersive OVD like HPMC/chondroitin sulphate. The Sinskey hook is passed through the main incision. The centre of the nucleus is felt with the hook which is then taken up to the equator of the nucleus tracing the surface of the nucleus. Once the equator is reached, the Sinskey hook is passed into the surrounding epinucleus or cortex. The pole of the nucleus is lifted out of the capsule (Fig. 2) and cartwheeled anteriorly and out of the bag till the entire nucleus comes into AC. This procedure may be difficult in small rigid pupils and small capsulorrhexis or when zonules are weak.
Fig. 2
Nucleus prolapse with the Sinskey hook
Bimanual Method
This technique requires two Sinskey hooks or one hook and an iris repositor. There are two ways of doing this:
1.
The hook or iris repositor is passed through the side port on the left side. The edge of the nucleus on that side is gently pushed posteriorly. When this is done the opposite pole of nucleus prolapses out of the bag. With the second Sinskey hook nucleus can be rotated anteriorly like in previous techniques (Fig. 3a).
Fig. 3
(a) Bimanual prolapse of the nucleus. (b) Bimanual prolapse of the nucleus
2.
In the second technique, AC is inflated with OVD. Nucleus is carefully displaced inferiorly with one Sinskey hook introduced through the side port on the left side or the main incision, thereby exposing the superior pole. OVD is injected under the exposed superior pole of the nucleus. The hook is placed under the superior pole of the nucleus and lifted to a plane in front of the anterior capsule. Then more OVD is injected under the exposed superior pole of the nucleus to create enough space for placement of a second Sinskey hook, and the nucleus is prolapsed into the AC by cartwheeling technique (Fig. 3b). This technique is more useful in mature cataract, brown cataract, myopia, pseudo-exfoliation, zonular dialysis and moderately dilated pupil. Instrument inserted under the upper part of the nucleus offers support and the required counter resistance to prolapse the nucleus into AC.
Prolapse in Special Situations
Small Pupil
If the pupil is not rigid, it can be stretched to one side with the help of an iris repositor inserted through the side port on the left side (Fig. 4). With Sinskey hook inserted through the main wound, the nucleus can be prolapsed in the usual manner. If the pupil is rigid one may have to resort to stretch pupilloplasty or multiple sphincterotomies or pupil expanders like Malyugin ring. It is not possible to prolapse the nucleus with iris hooks in place, but hooks can be used to make adequate-sized capsulorrhexis.
Fig. 4
Bimanual prolapse in small pupil
Large Hard Nucleus
It may be difficult to prolapse a large hard nucleus through regular-sized capsulorrhexis of 5.5 mm. Either a large capsulorrhexis has to be performed or it may be prudent to give multiple relaxing incisions to the capsulorrhexis margin to minimise stress on zonules. The same technique can be adopted in situations where large capsulorrhexis cannot be performed due to fibrosis of the anterior capsule and in zonular weakness.
Posterior Polar Cataract
Posterior polar cataracts are associated with primary dehiscence of the posterior capsule in 20 % of the cases [1], and hydrodissection is contraindicated. The majority of these cataracts present with soft nucleus which is difficult to prolapse by the regular methods. A special technique has been described called ‘lollipop technique’ where the visco cannula is passed into the centre of the nucleus like the stick inside a lollipop, and the whole nucleus is lifted out of the bag. In those cases of posterior polar cataracts with moderately hard and very hard nuclei, luxation can be achieved with Sinskey hook(s).
In cases of hypermature Morgagnian cataract, there is no counter support for the nucleus. AC is filled with OVD. An iris repositor is used to gently press at the capsulorrhexis margin at 9 o’clock position. The small nucleus, freely floating in the bag, will easily come into AC.
Nucleus Delivery Through Scleral Tunnel
Nucleus delivery out of the bag and the AC retaining integrity of the scleral tunnel and intactness of the internal structures of anterior segment including the corneal endothelium are an important aspect in MSICS. Various techniques have been in practice all over the world, and many surgeons have modified the original technique to develop their individual methods which work well in their hands. A sincere effort has been made to describe most of these techniques, and a link to videos demonstrating a few popular techniques is available at the beginning of the chapter. Various techniques that have been in practice may be classified as follows:
A.
Nucleus delivery techniques
1.
Nucleus delivery in toto
(a)
Hydroexpression
Blumenthal technique
With irrigating vectis
(b)
Viscoexpression
Phaco-punch technique
(c)
Sandwich technique
With Sinskey hook
With visco cannula
(d)
Hennig fish hook technique
2.
Nucleus delivery by phacofragmentation
(a)
Bisection or trisection
With metal bisector or trisector
With visco cannula
With metal wire snare
With nylon wire snare
Kongsap technique
Jaws slider pincer technique
(b)
Multifragmentation
Manual multifragmentation
Chop multisection and chopstick technique
Closed chamber manual phacofragmentation of Boramani
Prechop manual phacofragmentation
Quarter extraction technique
Each technique is described on the following lines: instruments, method and tips for a safe technique.
Nucleus Extraction In Toto
Hydroexpression
The basic principle of this procedure is to elevate hydrostatic pressure in the AC. As the main wound is opened and the floor of the tunnel is depressed, the nucleus comes out through the tunnel following the pressure gradient.
Blumenthal Technique [2]
This method is among the few methods that have withstood the test of time. Michael Blumenthal started this technique in 1990. Scores of ophthalmologists have adopted this technique and have modified the steps to suit their comfort levels. The concept of hydrodynamic delivery of the nucleus caught the imagination of many cataract surgeons worldwide. The concept of AC maintainer (ACM) which was introduced by Blumenthal is still widely used in various situations. The beauty of this technique lies in the fact that every step in SICS is performed without the use of OVD.
Instruments
1.
AC maintainer
2.
Sheet’s glide
AC Maintainer (ACM)
This is a 2.5 mm long metal cannula with a serrated external surface and a bevel. ACM is a very versatile instrument with 1 mm external diameter and 0.6 mm internal opening. With a 20 G MVR knife, a 1.5–2 mm intrastromal entry is made at 6 o’clock in a temporal to nasal direction. The ACM is introduced without flow with bevel up. After entering the AC, bevel is rotated down and BSS flow is resumed.
Sheet’s Glide [3]
This is a transparent plastic strip about 3–4 mm wide, 0.3 mm thick and about 3 cm long with a rounded and smoothened tip. Function of the glide is twofold:
1.
To glide the nucleus into the tunnel
2.
To provide a smooth surface for sliding of the nucleus
Procedure
Once the nucleus is luxated into AC, the tip of the Sheet’s glide is gently introduced through the section under the upper pole of the nucleus up to 1/3 of the way. With an iris spatula/McPherson forceps the tunnel is depressed by pressing on the glide. The nucleus gets engaged in the tunnel. The bottle height is increased to 70 mm, thereby increasing the hydrostatic pressure in the AC. Further continued pressure on the glide will cause the nucleus to shave off the epinucleus and mould itself into the tunnel till it is finally expelled out. This procedure is repeated again to expel the epinucleus.
Caution
The glide should be inserted under the nucleus and is pushed towards 6 o’clock and not posteriorly to prevent PC rent.
Sometimes the nucleus may get stuck at the corneal end of the tunnel. The nucleus can be engaged with a Sinskey hook and dialled out. The whole nucleus may come out or a pie-shaped piece will break from it. In that case one can rotate the nucleus so that the new reduced diameter engages and the nucleus expelled.
Hydroexpression with Irrigating Vectis
Instruments
1.
Irrigating vectis: 5 mm wide, with one to three 0.3 mm forward irrigating ports with a gentle superior concavity
2.
2.5 cm3 disposable syringe filled with BSS
Hydroexpression with an irrigating vectis is a simple technique using a combination of mechanical and hydrostatic forces. This is a single instrument technique and with OVD usage, safe for corneal endothelium.
Procedure
A superior rectus bridle suture may be placed which helps in applying counter resistance while extracting the nucleus. After luxation of the nucleus into AC, OVD is placed above and below the nucleus. The patency of the irrigating vectis is tested (Fig. 5a) before the surgery. The vectis without injecting fluid is introduced under the nucleus following the curve of the posterior surface of the nucleus till the vectis is seen over the iris inferiorly. It is important to avoid engaging iris between it and the nucleus in order to prevent iridodialysis. Margins of vectis can be seen through the nucleus except perhaps in dense white and black cataracts. The following manoeuvres should happen in quick succession for the safe removal of nucleus (Fig. 5b):
Fig. 5
(a) Testing patency of the irrigating vectis. (b) Nucleus extraction with irrigating vectis
1.
Irrigating vectis should be withdrawn slowly without irrigating. This helps in engaging the superior pole of the nucleus in the tunnel.
2.
Superior rectus bridle suture should be pulled tight to fix the globe.
3.
Fluid is injected slowly from the syringe while pressing the floor of the tunnel with the irrigating vectis. Hydrostatic pressure builds up in the AC as the nucleus, engaged in the tunnel, blocks the tunnel. The vectis is slowly pulled out and the nucleus also comes out with the vectis. Once the maximum diameter of the nucleus comes out of the tunnel, irrigation should be reduced to prevent forceful expulsion of the nucleus and sudden decompression and shallowing of AC.
Advantages of the Technique
AC remains formed throughout the surgery, and as the tunnel is depressed, the nucleus comes out without damaging the endothelium.
Management of Hard Cataract
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