Ординатура / Офтальмология / Английские материалы / Master's Guide to Manual Small Incision Cataract Surgery (MSICS)_Garg_2009

Figure 34.5

Figure 34.6

needle is that aqueous rapidly fills in the lumen of the needle, leading to collapse of the anterior chamber. This can be prevented by obliterating the lumen of the needle with a mallet or crushing with artery forceps. The MVR blade used for side-port incision costs 20 times more than the above mentioned needle (Figures 34.5 and 34.6).

Nucleus Fragmentation and Nucleus Delivery

The nucleus can be fragmented in the anterior chamber by various techniques, like using snare, bisector or trisector, phacoscissors, etc., whichever method the surgeon is comfortable with. The main goal of nucleus fragmentation is to achieve an astigmatically neutral, small scleral incision, taking care that the endothelium is not compromised during any of these manoeuvers. Once the surgeon is competent and consistent enough in nucleus fragmentation, then a lot of time can be saved during the initial tunnel-making and during nucleus delivery.

Figure 34.7

Cortical Aspiration

Cortical aspiration can be done by means of either an anterior chamber maintainer combined with aspiration cannulas of different gauges or by means of simcoe irrigation-aspiration cannula. Different aspiration cannulas can be prepared according to the amount and nature of the cortical matter left in the capsular bag. For thick epinucleus, a large bore viscocannula can be used with a 5 ml syringe to rapidly aspirate the same. For soft, fluffy lens matter, a narrow bore cannula suffices so that aspiration is more controlled. These cannulas are cheaper and easy to maintain.

Silicon Bulb

A 30 cc re-usable silicon bulb filled with BSS can be used by the surgeon’s assistant to keep the cornea moist during the surgery. A single filling is enough for a long operative list. Changing syringes for every case is thus avoided.

Thus, to summarise, it can be said that MSICS is the procedure of choice when it comes to tackling a huge load of cataract surgeries without compromising on the visual outcome and without being hard on resources at hand (Figure 34.7).

REFERENCES

1.Shah A. “Best out of waste” in SICS 2003.

2.Byadgi V. MSICS through temporal 3.5 mm corneal tunnel. Journal of ISMSICS, Dec 2006.

3.Perrin R. SICS using Perrin cataract scissors and forceps. Aust. NZ J Ophthal, Feb 1990.

4.Kansas PG, Sax R. SICS using manual phacofragmentation technique. J Cataract Refract Surg 1998;14(3):32830.

INTRODUCTION

Manual Small Incision Cataract Surgery (MSICS) is a good alternative to expensive technique of phacoemulsification. It can be performed in almost all types of cataract.

This technique has almost all the advantages of phaco surgery. Important steps involved in SICS are:

a.Wound construction: Scleral tunnel is usually preferred.

b.Nucleus Management: This includes:

•Prolapsing of nucleus in AC.

•Removal of nucleus out of the wound.

There are different methods for removal of nucleus out of the wound.

c.Implantation of intraocular lens.

Nucleus management consists of:

a. Delivery of nucleus into the anterior chamber. a. Removal of nucleus out of the wound.

DELIVERY OF NUCLEUS INTO THE

ANTERIOR CHAMBERS

After construction of good adequate capsulorhxis and hydrodissection, nucleus is prolapsed in the anterior chamber. This is done either by hydrodissection, viscoexpression or with use of Sinskeys hook by rotating the nucleus.

REMOVAL OF NUCLEUS OUT OF THE WOUND6

This is very important part of SICS. There are different methods available for it:

1. The Blumenthal technique

Arif Adenwala, Ashok Garg (India)

2.Use of irrigating vectis

3.Visco-expression

4.Phacofracture

5.Manual phacofracture Cardona’s technique

6.Phaco sandwich technique

7.Manual multiple phacofragmentation

8.Prechop manual phacofragmentation

9.Quarter’s extraction technique

10.Chopsticks technique

11.Use of claw vectis

12.Plain wire vectis

13.Fish hook technique

14.Phaco-punch technique

15.Hybrid technique

16.Slider pincer technique

17.Double wire Snare splitter technique.

The preliminary step in almost all the methods is prolapse of nucleus in to the anterior chamber.

The Bluementhal Technique6

The important feature of nucleus delivery by this technique is hydrodissection of the nucleus followed by its hydrodynamic expression. This technique was indicated by Dr Michael Bluementhal.

Method Initial step is fixing of anterior chamber maintainer. It is usually inserted from the temporal side. The tube is attached to BSS bottle which is held 50-60 cm from patient’s eye. The height can be adjusted. The next step is to engage the nucleus into the wound. The delivery of nucleus occurs by hydropressure generated by AC Maintainer.

Lens glide is passed below the nucleus and with slight pressure over the scleral lip, the nucleus is

Figure 35.1: Nuclear Prolapse: Sinskey’s hook placed behind the superior pole of nucleus

(Courtesy: Dr KPS Malik and Dr Ruchi Goel)

Figure 35.2: Nuclear prolapse out of the bag: superior pole is lifted up using Sinskey’s hook as a crowbar (Courtesy: Dr KPS Malik and Dr Ruchi Goel)

removed. Instead of lens glide we can also apply pressure with needle over the scleral lip.

If the AC is shallow you can increase the height of bottle and vice versa.

Advantages18

•AC is formed at all the times

•The procedure is not dependent on viscoelastics

•No Sophisticated Instruments are required

•It can be used for all types of cataract and Capsulotomy.

Disadvantages18

•Failure to manipulate the nucleus in the anterior chamber can cause zonular dialysis

•Keeping the bottle at adequate height is important; otherwise it may lead to frequent changes in the depth of the anterior chamber

•Traumatic delivery can damage the corneal endothelium.

Nucleus removal using irrigating wire vectis7: Irrigating Wire Vectis is use to deliver the nucleus either by hydroexpression or by viscoexpression.

Instruments Various sizes of vectis are available. It has two surfaces, viz. anterior concave surface and posterior surface. The anterior end had three 0.3mm openings. The posterior end is attached to syringe or infusion set.

Technique Delivery of nucleus in the anterior chamber. Push the viscoelastic and insinuate the irrigating vectis below the nucleus. Apply counter pressure by holding

Figure 35.5: Mechanism of nucleus delivery with irrigating vectis (Courtesy: Dr KPS Malik and Dr Ruchi Goel)

superior rectus forceps. Now start the irrigation and pull the vectis out of the wound. Give pressure over the scleral lip posteriorly.

Pressure must be built up in the anterior chamber before pulling the nucleus out. Posterior lip depresssion is important part of nucleus delivery.

Mechanism of nucleus delivery7

It includes:

a.Mechanical pull by irrigating vectis

b.Internal hydrostatie pressure

c.Scleral stretching by the nucleus

d.Posterior scleral Lip depression

e.Counter balance force by superior rectus forceps.

Advantages

•Anterior chamber is maintained after the nucleus delivery

•Damage to corneal endothelium is minimal.

Problem Associated

i.Damage to iris: Iris trauma can occur while insinuating the irrigating vectis below the nucleus. This can be prevented by pushing the viscoelastic above and below the nucleus. This pushes the iris posteriorly. Insert the vectis below the nucleus and deliver out the nucleus.

ii.Posterior capsular tears: It is quite rare with every irrigating vectis.

Visco Expression6

This is another technique of removal of nucleus out of the wound. It is a common technique which is used by many surgeons due to its added advantages.

Technique The preliminary step is to prolapse the nucleus out into the anterior chamber. Before this a

good hydrodissection and hydrodilineation is very important. Now push viscoelastic into the anterior chamber. While pushing the viscoelastic engage the nucleus into scleral lip and then apply pressure over the posterior scleral lip and deliver the nucleus out. Viscoelastic is continuously pushed while removing the nucleus.

Advantages

•Viscoelastic material acts as a cushion or support to the corneal endothelium and so chances of its damage is minimal.

•Anterior chamber is always maintained.

•Damage to iris tissue is less.

•Incidence of posterior capsule tear is also less.

Disadvantages

•Large quality of viscoelastic is required. This becomes expensive.

•If visocelastic material is not removed completely, there is increase incidence of postoperative uveitis and secondary glaucoma.

•Not suitable for black cataracts.

Phacofracture3

This technique was described by Peter Kansas.14,17

Technique: The initial step is to prolapse the nucleus out of the bag. Viscoelastic is pushed both above and below the nucleus in the anterior chamber.

The solid curved vectis is insinuated under the nucleus and the nucleotome is positioned on the anterior surface of nucleus. Both instruments are brought close to each other. This will lead to splitting of the nucleus in to two halves.

Both the halves are seperated and each half is removed with nuclear forceps or by pushing viscoelastic inside the AC.

Modification: This technique involves the use of Sinskey hook and wire vectis to sandwich the nucleus and removing it out of the wound.

The anterior chamber should always be deep throughout the surgery.

Advantages: Manual phacofracture is a easy way that eliminates the hazards of the phacomachine with the ability to perform small incision with less expenses.

Complications

a.Damage to iris tissue and superior Iridodialysis can occur during fragment extraction. This can be prevented by using lens glide or by pushing the iris posteriorly by pushing viscoelastic.

Figure 35.6: Phacofracture technique using Sinskey Hook and Wire Vectis (Courtesy: Dr KPS Malik and Dr Ruchi Goel)

Figure 35.7: Separation of the nuclear fragments (Courtesy: Rozakis Alternative to small

incision cataract surgery)

b.Capsular disruption can occur.

c.Corneal Endothelium damage: This can occur due to passage of 2 instruments in AC and the maneuvering required to sandwich the nucleus and removing it out of the wound.

The other techniques for phacofracture includes:

A.Bisector technique:6 This requires the use of bisector. It is type of modification of phacofracture method.

Figure 35.8: Removal of the nuclear fragment (Courtesy: Rozakis Alternative to small incision cataract surgery)

Figure 35.9: Removal of the last piece of the nucleus (Courtesy: Rozakis Alternative to small incision cataract surgery)

The preliminary step is to insinuate the wire vectis behind the nucleus and the bisector is passed on the anterior surface of the nucleus.

The two instruments are maneuvered toward each other: leading to cleavage of nucleus into two halves. Constant pressure on bisector on vectis splits the nucleus into two halves. Both the halves are seperated and removed by using nucleus holding forceps with vectis or by using viscoelastic material.

Figure 35.10: Phacofracture using Trisector (Courtesy : Dr KPS Malik and Dr Ruchi Goel)

B.Using Trisector:13 It is similar technique of phacofracture in which bisector is used thus dividing the nucleus into three pieces.

The trisector consists of 2 longitudinal limits which are sharp in the posterior end. The bisector is passed under the nucleus and pressed toward the nucleus. This divides the nucleus into 3 pieces. Each piece is then removed with serrated forceps.

Advantages

•Safer delivery of nucleus

•Less dependence on assistant personnel

•The elimination of phacomachine

•The cost-effectiveness.

nucleus. The lens loop/snare is passed below the nucleus. The lens is shifted into vertical position and brought across the nucleus. The loop is constructed by pulling posteriorly on the coil. This leads in the division of nucleus into the halves.

The two halves are then seperated by injecting viscoelastic material. Each halve is the removed with fine toothed forceps.

Advantages

•Fragmentation of the nucleus is safe an nonexpensive technique.

•It can be used for hard cataract where phaco is difficult.

•It can also be used in cases of zonular dehisences.

•It is safe, smooth, cost-effective and easy to use technique.

Disadvantages

•Difficult in small pupils

•Difficult in soft nuclei and subluxated lens

•It can cause some damage to the corneal endothelium.

Manual Phacofracture Cardona’s Technique

In order to perform the manual bisection of the nucleus according to Cardona’s technique, it is important to dislocate the crystalline nucleus in the anterior chamber.

Technique: Scleral tunnel of about 5 mm is made. After capsulorhexis and hydroprocedures, nucleus is prolapsed in the anterior chamber.

Through the tunnel incision, vectis is inserted under the nucleus and bisector is placed onto the nucleus. Nucleus is supported by the non-slipping vectis and fragmented into two with the sawing movement of bisector. The nuclear pieces are then removed out of the scleral tunnel wound.

Phaco Sandwich Technique4,11

This technique was introduced by Luther L Fry. This procedure require 7.5 mm opening for most of the nuclei and large incision for harder cataract.

Technique Tipping up of the nucleus is very important step. The capsule and iris are hold with iris spatula and the nucleus is nudged toward 6’oclock with hook. The superior pole of nucleus is then caught with spatula and tipped up.

The viscoelastic is placed between superior pole of nucleus and posterior capsule. The iris is pushed posteriorly with viscoelastic and the nucleus is elevated with the spatula. The lens loop is paced beneath the nucleus and spatula is placed on top of nucleus. Both instruments are approximated leading to sandwiching of the nucleus.

Thus with two handed technique the nucleus is removed.

Advantages

•This technique can be used for all pupil sizes and almost all types of nucleus

•It can be used with large can opener capsulotomy.

•Safe and easy technique which does not require expensive instrumentation.

Disadvantages

•Large amount of viscoelastic material is required

•Not suitable for very soft cataract

•Relative contraindication for subluxated cataract.

•Large capsulorrhexis is required

•Increase chance of damage to the posterior capsule

•Iridodialysis–Iris may get caught when both the instruments are approximated and removed.

Complications

The most common complication seen in one study done are:

a.Posterior capsular rupture

b.Loss of vitreous

c.Transient corneal edema.

Modifications:6 In this technique, the lens loop and spatula is not used. The instruments used are plain wire vectis and viscocannula.

The plain wire vectis is insinuated below the nucleus and viscoselastic is pushed above and below the nucleus. The viscocannula is placed in fornt of the nucleus. The nucleus is sandwich with these instruments and removed. The viscoelastic is injected, while the nucleus is brought out.

Sinskey Hook can also be used instead of cannula.

Manual Multiple Phacofragmentation6

It is technique of manual SICS in which the nucleus is fragmented into multiple pieces and then removed.

Technique: In this procedure special instruments are required.

Instruments

a.Nucleotome: It is racquet shaped instrument of length 8 mm and width 2 mm. It is divided by 3 transverse bars. It is held at 45° to long handle.

b.Spatula: The shape of spatula should be same as nucleotome.

c.Manipulators: Used to collect the nuclear fragments in to center.

Procedure: The initial steps remain the same. The spatula is passed below the nucleus present in the anterior chamber and the nucleotome is placed over the nucleus.

Viscoelastic should be sufficient to keep the AC deep. Both the instruments are then brought close to each other. This causes fragmentation of large nucleus into small pieces.

The manipulators are used to remove the lens fragments from scleral lip into center of wound. The small pieces are then removed either by using viscoelastic or with the help of nucleus holding forceps.

Advantages

•Hard cataracts can be removed through the small wound by making small nuclear pieces.

Figure 35.12: Instruments used for phaco fragmentation. A. Nucleotome, B. Spatula and C. Manipulators (Courtesy: Dr KPS Malik and Dr Ruchi Goel)

Disadvantages

•Damage to corneal endothelium is quite high as two instruments are passed in the anterior chamber.

•Damage to iris tissue is also seen. This is seen both while inserting and removing the instrument.

•Use of special instruments like nucleotome which may not be available everywhere.

Prechop Manual Phacofragementation12

In this technique of cataract surgery, the nucleus is manually split into 2 fragments with prechopper forceps and then removed.

Technique: After good rhexis and hydroprocedures viscoelastic is injected into the anterior chamber. The sinskey hook is passed through side port to stabilize the nucleus. The prechop forceps is inserted through the wound and passed into center of nucleus core. Opening the forceps will cause splitting of nucleus into 2 pieces. Complete division of nucleus should occur other wise, the steps are repeated. Each piece is prolapsed into anterior chamber and then removed using viscoelastics or serrated with the help of nucleus forceps.

Figures 35.13A and B: Manual multiphacofragmentation (Courtesy: Dr KPS Malik and Dr Ruchi Goel)

Advantages

•This technique of phacofragmentation is done in the bag and not in anterior chambers and so cause less damage to corneal endothelium

•Does not require expensive instruments

•Visual recovery is rapid.

Disadvantages

•Not suitable for hard/black cataracts

•Also not suitable for subluxated cataract

•Initial learning curve for nucleus fragmentation is very important.

Quarters Extraction technique for Manual Phacofragmentation9

Technique: In this procedure the nucleus is manually split and fragments removed. After capsulorhexis, hydrodissection, hydrodelineation and the surface cortex aspiration, the edge of the nucleus is prolapsed into the AC.

The front quarter of the nucleus is cut and removed with nuclear punches. A corner of the remaining three quarter of nucleus is wedged into the wound and rotated out with a claw vectis.

Disadvantages

•This technique is not suitable for very hard/large nucleus.

•It requires learning curve for fragmentation of the nucleus.

Chop Bisector/Chop Trisector and Chopsticks Technique for Extraction of the Nuclear Fragments

It is alternative form of manual phacofragmentation in which chop bisection/chop trisection or chop multisection is done.

Technique: The division of the nucleus is carried out by slipping a phacochopper from 6 o’clock to 12 o’clock and applying counter chopper with another manipulator introduced below the nucleus. The extraction of the nuclear fragments is carried out by viscoexpression with the help of vectis or by picking the fragments with the spatula and the chopper. The extraction of

nuclear fragments with the Chinese chopsticks technique allows a better adjustment of the final size of the incision to the size of the nuclear fragments.

Use of Claw Vectis10

It is simpler one handed technique using a claw vectis. It is a vectis with a claw placed on its tip.

Technique: Nucleus is delivered into anterior chamber. Viscoelastic is injected in the anterior chamber. When the nucleus is pulled through the scleral tunnel, it is fixed by the claw and then removed. Viscoelastic is injected while removing the nucleus, so that the corneal endothelium damage is less.

Advantage

•It is better than two handed sandwich technique which may be difficult for many surgeons.

Disadvantage

•Special instruments (claw vectis) are required.

•Damage to iris tissue.

Using of Plain Wire Vectis6

Technique: The Preliminary step is the delivery of nucleus into the AC. Push viscoelastic above and below the nucleus. This will prevent the damage of corneal endothelium. Then judge the size of tunnel depending on grade of nucleus.

Pass the wire vectis below the nucleus, so that the nucleus lies in concavity of vectis. Remove the vectis out with simultaneous pressure over the scleral lip

Figure 35.15: Use of wire vectis (Courtesy: Rozakis Alternative to small incision cataract surgery)

Figure 35.16: Delivery of nucleus using wire vectis (Courtesy: Rozakis Alternative to small

incision cataract surgery)

posteriorly. The pressure over scleral lip will open the scleral wound and will help in delivery of nucleus.

Advantage

•Use of single instrument and so less chance of damage to surrounding structures.

•Less expensive technique.

Disdvantage

•Increase chance of iridodialysis, common at the 6’o clock position.

•Anterior chamber becomes shallow after delivery of the nucleus.

Figure 35.17: Fish Hook showing the bent top of the 30 G ½ inch needle (Courtesy: Dr A Hennig, Nepal)

Figure 35.18A: Insertion of the Hook between Nucleus and posterior capsule (Courtesy: Dr A Hennig, Nepal)

Figure 35.18B: Hook extraction of the nucleus out of the capsular Bag (Courtesy: Dr A Hennig, Nepal)

Fishhook Technique8

In 1997 Dr Albrecht Hennig used a small hook for nucleus extraction instead of anterior chamber maintainer and hydro-expression of the nucleus. It is named as Hennig technique or Fishhook technique.