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

Figure 21.2: Flow through ACM pushes the vitreous back in case of posterior capsular tear during cortical wash

PHACOFRACTURE AND PHACOSECTION

In both these techniques, the construction of corneoscleral differs from the previous method. Here, the size of the internal and the external incision are equal and the side pockets are not dissected. The incision size in phacofracture varies from 4.5 to 5.5 mm whereas in phacosandwich it is kept from 6-7 mm. After dissecting the tunnel, two side ports are created as described in the previous section. Capsulotomy, fixing the ACM, hydroprocedures and nuclear prolapse are performed in the usual manner. After suspending the nucleus in an ocean of viscoelastic, an irrigating wire vectis is insinuated behind the nucleus and a Sinskey’s hook is placed on the top.

In phacosandwich technique, the nucleus is delivered sandwiched between the two instruments while the assistant injects viscoelastics through the ACM, maintaining a deep anterior chamber throughout (Figure 21.3).

In phacofracture technique, the two instruments are approximated towards each other to crush the nucleus into two halves, while the assistant injects the viscoelastic through the ACM. The two halves are separated and each half is brought out sandwiched between the microvectis and the Sinskey’s hook (Figure 21.4).

ACM IN PHACOEMULSIFICATION

We advocate use of ACM in all grades of cataracts during the learning phase. It is especially useful in grade

Figure 21.3: Phacosandwich technique using ACM

Figure 21.4: Phacofracture technique using ACM

Figure 21.5: Microincisional surgery using ACM

4/5 nuclei where higher vacuum is required to prevent chamber collapse. After the trenching is complete, the vacuum is increased to 200 mm of Hg and ACM flow is put on. The nuclear pieces are then engulfed without the danger of chamber collapse.

Micro-incisional Surgery

In Micro-incisional surgery, a clear corneal tunnel 1.5 mm in length is created. 3 side ports are made at 10 o’clock, 3 o’clock and 7o’clock positions for performing capsulorhexis, inserting the irrigating chopper and inserting the ACM respectively.

A 30 degrees phacotip with a shortened sleeve is used. The shortened sleeve reduces the temperature created by phacotip vibrations, preventing corneal burn. A 20 G irrigating chopper is connected to a BSS bottle. ACM is attached to another BSS bottle. Trenching is performed keeping the machine parmeters as usual

(Flow: 25 cc/mt, Vacuum: 20 mm of Hg and Power: 50 to 80%).

ACM is put on during the trenching itself. After the trenching is complete, vacuum is increased depending upon the hardness of the cataract and the nucleus is emulsified (Figure 21.5).

Secondary Cortical Aspiration

Patients requiring aspiration of residual cortex can be dealt under topical anethesia. After fixing the ACM in the usual manner, the cortex can be easily aspirated through a side port created at any convenient position adjacent to the limbus.

In conclusion, ACM is an inexpensive, useful instrument, which can be employed in various techniques for maintaining a deep anterior chamber and thereby preventing endothelial damage, a dreaded complication of cataract surgery.

DO’S AND DON’TS

Do’s

1.Check the ACM for patency before use.

2.Always make the port for ACM valvular and of adequate size.

3.Insert the bevel completely into the chamber.

4.Insert the ACM parallel to the plane of iris.

5.Hydrate the ACM port at the end of the surgery.

6.Perform the manipulation of nucleus through side port to enable chamber stability by ACM.

Don’ts

1.Do not try to insert it with the chamber collapsed as its tip can injure the intraocular structures.

2.While injecting viscoelastic through the ACM, forceful injection avoided to prevent nucleus drop.

3.In case of equatorial extension of capsular tear, it should not be used by a novice surgeon.

INTRODUCTION

Temporal manual small incision cataract surgery (SICS) is an important approach to cataract surgery, as shifting of the tunnel around the cornea has given the manual SICS surgeon a much better control over the postoperative refraction.

Cataract surgery was once considered a simple rehabilitative procedure. But over the years, it has been transformed into an increasingly precise refractive surgery. The goal is no longer, just being able to make the patient mobile and self sufficient in looking after himself, but to achieve emmetropia.

Manual SICS has:

•Few complications,

•Requires little extra investment and

•Provides all the advantages of

—Small incision,

—Intraocular lens (IOL) implants and

—Anastigmatism.

Placing the incision in the incisional funnel in the planned meridian induces:

•A more predictable

•Stable and

•Less astigmatism.

Incision in temporal manual SICS may be made:

•Scleral or

•Limbal.

Incision in temporal manual SICS may be made:

•Straight

•Blumenthal’s straight with radial cuts at the ends,

•Frown or

•Chevron V-shaped.

Temporal manual SICS is performed in patients having:

•No astigmatism

•Against the rule astigmatism

•A superiorly placed trabeculectomy bleb

•A superior limbal pathology

•A deep set eye with a very prominent eyebrow or

•A large hair knot on the head, as supported by the holy men in India.

SURGICAL TECHNIQUE

•A wrist rest is a great help (Figure 22.1).

•Peribulbar anesthesia.

•Balanced weight is used to make the eyeball hypotensive (Figure 22.2).

•Lid speculum.

•Bridle rectus suture not required.

•Stab side port 5° to the right of intended scleral tunnel.

Figure 22.1: Wrist rest

Figure 22.2: Balanced weight

•Trypan blue introduced into the anterior chamber (AC) under an air bubble.

•AC is irrigated instantaneously with ringer lactate.

•And the AC is then reformed with viscoelastic.

•Large capsulorhexis (5.5-6 mm) with a 30G needle cystitome through the side-port.

•Lateral canthus based conjunctival flap.

•Sparingly applied heat cautery.

•Sclero-corneal or Limbo-corneal tunnel.

•Tunnel is made with a bevel up crescent knife.

•AC entered and tunnel completed with keratome.

•Hydrodissection and hydrodelineation performed.

•Nucleus rotated ‘in-the-bag’.

•Presenting pole of the nucleus prolapsed into the AC.

•Viscoelastic injected around the nucleus.

•Nucleus delivered with:

–a fish hook made of 30G needle,

–an Irrigating vectis alone or

–by the Sandwich technique, or

–by the Viscoexpression technique.

•Epinucleus is hydro or viscoexpressed.

•Residual cortex aspirated and the posterior capsule polished with a reverse Simcoe cannula.

•5.25 mm Intraocular lens implanted ‘in-the-bag’.

•IOL can be dialed and centred, if necessary.

•Conjunctival flap reposed and eye-dressed.

Figure 22.3: Trabeculectomy bleb

Figure 22.4: Hypermature senile cataract with trabeculectomy bleb

INDICATIONS

•Trabeculectomy bleb (Figures 22.3 to 22.5),

•No astigmatism or

•ATR astigmatism (i.e. no bleb)

•Superior limbal pathology

•Deep set eye due to lack of orbital fat or a prominent brow (Figure 22.6)

•A large hair knot on the head, as supported by the holy men in India (Figures 22.7 and 22.8).

RESULTS

•All our cases exhibit, an astigmatic error of less than 0.75 D.

Figure 22.5: Same case as above—Postoperative Day 6

Figure 22.6: Deep set eye due to lack of orbital fat and with a prominent brow

Figure 22.8: Large hair knot on the head (head end profile)

•All, amongst our cases, exhibited a ‘with the rule’ shift in astigmatism. The change in astigmatism ranged from no shift to 0.25 to 2.50 D.

In 84% cases of our cases, the shift was in the range of 0.50 to 1.50 D (Figure 22.9).

Interestingly, all cases exhibiting a with the rule shift of more than 1.00 D were those who had a preoperative. ATR astigmatism of more than 1.00 D. (This is explained by the fact that the tunnel was made limbal and/or wider, or more towards the cornea) (Figure 22.10 to 22.15).

Figure 22.10: Temporal incision in SICS OD (Postoperative Day 1)

Figure 22.11: Temporal incision in SICS OS (Postoperative Day 15)

Figure 22.12: End result in a case of temporal SICS after trabeculectomy

Figure 22.13: Case of pseudo-exfoliation (for temporal SICS)

Figure 22.14: Same case of pseudo-exfoliation as in Figure 22.13 (after temporal SICS—Postoperative Day 7)

COMPLICATIONS (in our series of 250 cases)

Figure 22.15: A leaking section after temporal SICS

DO’S AND DON’TS OF THE PROCEDURE

Do’s

1.Preoperatively the patient is given acetazolamide tablet 250 mg orally, and digital massage, super pinky or balanced weight is used after local anaesthesia has been given, to induce hypotension of the eyeball. Most procedures of nucleus delivery in SICS—namely fish hook technique, with an irrigating vectis alone or by the Sandwich technique or by the visco-expression technique require a hypotensive eyeball.

2.Sit on the side of the eye to be operated, i.e. position yourself to the temporal side of the eye.

3.There is no need to use a superior rectus bridle suture, thus unnecessary trauma to the eye tissues is avoided.

4.The temporal side of the eye to be operated is kept slightly lower than the nasal side. Due to this positioning, the irrigating fluid flows down through the lateral canthus. It does not collect in the medial canthal region and superior fornix. So, there are no chances of back flow of the fluids, into the AC.

5.The external scratch incision may be placed right on the limbus instead of going through the sclera; this helps us avail all the advantages of a limbal incision, e.g. early healing.

6.By opting for the temporal approach we are able to bypass the eyebrow in a deep-set eye, making access to the globe and thus the surgery easier.

7.In oblique astigmatism, the temporal approach is slightly modified without much effort; the tunnel is moved superiorly or inferiorly, making the tunnel tangential to the steep meridian.

Don’ts

1.An anterior chamber maintainer (ACM) is never used when performing a temporal manual SICS, as the conventional site of placement of the ACM at 6 o’clock is not possible and placing the ACM at the nasal end is not convenient.

Phaco says sophistication in surgery is basic obligation, and

Manual phaco says simplicity in surgery is basic obligation

HOW TO START?

Following are the suggestions to master this technique. A newcomer should not waste the time in doing scleral tunnel incision. One should start with routine limbal or corneal incision. Select an eye with widely dilated pupil and a white cataract or moderately hard nucleus. Initially make a small limbal or corneal incision, inject viscoelastic into the anterior chamber and do either capsulotomy or capsulorehexis. Extend the incision to the required length. Do proper hydrodissection and hydrodelination.

The next most important step is the prolapse of nucleus into the anterior chamber. First master this step and if you are not able to bring the nucleus into the anterior chamber initially then, convert SICS into routine extracapsular surgery. Once you gain sufficient confidence in bringing nucleus into the anterior chamber, the next step is nucleus fragmentation. Though it appears technically more difficult, it is made easy with the use of the modified snare developed by me. After making the nucleus free floating into the anterior chamber, engage the nucleus easily into the loop and bisect it. After doing few cases it is observed that the things are getting easier. After the nucleus division, remove the half of the nucleus with any suitable method.

Close the wound partly by sutures, aspirate cortex by any suitable method or try bimanual I/A. Slowly go on reducing the size of incision. Try to go posteriorly

towards the posterior limbus. Slowly develop scleral tunnel incision. Decrease the number of sutures. At last you will reach to a stage where scleral incision is 2.5 mm away to the anterior limbus and the chord length is 5.5 mm without suture.

INTRODUCTION

Cataract surgery is incessantly changing. New techniques and procedures are making our minds unstable. With the modernization, the cost of surgery is increasing to the surgeon, patient and to our nation. Due to its cost and steep learning curve, we are in search of a parallel intermediate technology that has all advantages of phaco surgery and simultaneously simple, safer and cheaper. Small incision cataract surgery attracts many of us. We are attending many workshops, conferences and spending lot of money on costly surgical instruments. We are observing various techniques. Still they do not satisfy us. We are in search of an ideal technique that fulfills all ideal criteria’s for small incision cataract surgery (Manual phaco).

For beginners a phacoemulsification technique is high-risk and complicated. Usually every phaco surgeon is under stress during surgery. He may come across to worst complication like nucleus drop at any stage of surgery and thus safety margin for the beginner reduces to the great extent. Beginner should learn all the surgical techniques, which are safe for him and to his patients.

Ideal criteria for small incision cataract surgery are:

•Incision should be 5.5 mm or less than it.

•Method should have minimum learning curve to enable any beginner to perform it.

•Any extracapsular surgeon should be able to perform it.

•It should be safe, cost effective and result oriented.

•It should be possible to perform at any place.

•It should be performed with can-opener capsulotomy or capsulorhexis.

•It should easily divide all types of nucleus from soft to hardest.

•It should be applicable on community basis.

In India, about 60 to 70% of the patients have hard cataract. These patients have large nucleus. Such types of cataracts are difficult to manage with phacoemulfication and even with available alternate small incision techniques. We know that, small incision will result in less astigmatism, earlier stabilization, and quicker and comfortable postoperative eye.

Various types of techniques are available for small incision cataract surgery. In all the techniques the nucleus is to be brought into the anterior chamber. I have tried all types of techniques, but it has few drawbacks and limitations. In few patients, fracturing of hard nucleus was difficult with sharp spatula. Lens loop and spatula failed to remove large nucleus through small incision. Trisector and spatula did not cut hard nucleus. In few patients, sheets glide and ACM were failed to remove large nucleus through small incision. Wire loop failed to engage the large nucleus easily.

In all these techniques it requires a large incision to remove large nucleus. All these techniques are useful in soft and small cataracts and they have limited usage in hard and large cataracts. In routine practice, we frequently see hard and large cataracts and it was necessary for an ideal technique that fulfils all these criteria.

At last, I have designed a technique that, to my knowledge, fulfills almost all the criteria of an ideal of small incision cataract surgery. This is how I do small incision cataract surgery and I hope you might like to do it too.

I have made various surgical instrument and cannula from disposable needle.

INSTRUMENTATION

Using simple tools like abrasive stone, flat jaw pillar, blade cutter and needle holder one can make simple surgical instrument for small incision cataract surgery.

Cannula

We need variety of cannula during cataract surgery. These cannulas has different types of opening at the tip. These cannula can be easily from disposable needle.

Figure 23.1

Hydrodissection Cannula

This type of cannula can be used for cortico capsular cleavage and hydrodissection. This is made of 26 G cannula having opening facing upward.

Hydrodelineation Cannula

This type cannula easily separates the epinucleus from outer nucleus by passing pointed tip of the same in to the substance made of nucleus. This is made of 24 G needle having bevel like opening.

Nucleus Prolapse Cannula (Figure 23.1)

This is my favorite cannula and is used to prolapse the nucleus into the anterior chamber. This is made of 22 G needle with opening of the tip facing downward. This cannula is connected to irrigating bottle. With the irrigation on, the tip of the cannula is passed in the substance of the cortex under the capsular rim up to the equator. The fluid goes under the capsule, behind the nucleus. The pressure is built up into the capsular bag and one pole of the nucleus comes out of the capsular rim and prolapses into the anterior chamber.

Modified Viscoelastic Cannula (Figure 23.2)

This cannula is made of 22 G needle. The opening at the tip is facing upward. It has many advantages. Each time when viscoelastic is injected, some amount of viscoelastic continuously spreads under the endothelium. It protects endothelium during intraocular handling. When the nucleus is prolapsed in to the anterior chamber, viscoelastic is easily spread in-between nucleus and endothelium producing easy cleavage.

Figure 23.2

Snare

I have made a snare that is now available in the market as “Dr Anil Shah’s Snare” for small incision cataract surgery. This snare is made from waste disposable needle and steel wire. The surgical technique was presented at various national and international conferences and was awarded as “innovation in ophthalmology” by Maharashtra Ophthalmologic society.

Making Dr Anil Shah’s Snare Bisector

(Figures 23.3A and B)

•Take 18-G needle and rub its tip on abrasive stone to make the tip blunt (Figures 23.4A to L).

•On the side wall of the needle, at the tip two small holes are made opposite to each other by rubbing wall of the needle on the abrasive stone.

•Take about 9 inch of steel wire (36 G Bango String Piano wire available at any departmental store) and pass both end of wire through side hole opening of the needle. The wire passes through the lumen and comes out of the hub of the needle. A loop of about 13 to15-mm size is formed at the blunt tip of needle.

•Take another 18 G needle, rub its tip and make it blunt. Pass the above remaining end of steel wire through this needle. Fix the steel wire in to the wall of the 18 G needle by nose pillar. This needle acts as a handle to the snare.

Making Dr Anil Shah’s Trisector (Figures 23.6A to C)

•Take 16 G needle and rub its tip on abrasive stone to make the tip blunt.

•On the side wall of the needle, at the tip two small holes are made opposite to each other by rubbing wall of the needle on the abrasive stone.

•Take about 2 wires off 9 inch of steel wire (36 G Bango String Piano wire available at any departmental store) and pass both end of wire through side hole opening of the needle. The two wires passes through the lumen and comes out of the hub of the needle. Two loops of about 13 to 15 mm size are formed at the blunt tip of needle.

•Keep both loops in such a direction that the concavity of the loop is facing opposite to each other.

•Take another 18 G needle, rub its tip and make it blunt. Pass the four wires in to the handle of 18 G. Fix the steel wires in to the wall of the needle by nose pillar. This needle act as a handle to the snare.

•The snare is made by above method that can be sterilized. It can be used for trisecting the cataract (Figure 23.7).

Advantages of Two Holes at the Tip of Snare

The two holes at the tip of the snare is a magic concept and have totally changed the outlook.

•Due to these holes there is no twisting of wire loop and the loop remains totally open while pushing and pulling into the snare loop in to the anterior chamber.

•Appropriate size of loop is to the size of nucleus is made, without touching the vital intraocular structure.

•Due to two holes at the tip of the snare, rotation of the loop in to the anterior chamber is passable. When the handle is rotated externally the loop gets rotated internally without collapsing the anterior chamber or displacing the nucleus. Due to this, very easy