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

experience is gained. Where cost is a factor, if an X-suture is needed with these larger incisions, the 10-0 nylon suture can be placed in a 4 × 4 and can be autoclaved and reused (Vicryl® or Dexon® will not withstand autoclaving).

It is possible to engage iris inferiorly between the spatula and nucleus, particularly in a very mature cataract where you cannot see the lens loop through the nucleus. This can result in an iridodialysis. This has occurred to me 3 times out of approximately 10,000 cases. Just be aware this can happen, and it will not happen to you.

As with any surgical procedure, this procedure is more easily learned by watching video tape than with a written description. This procedure was shown on Bobby Osher’s Video Journal of Cataract and Refractive Surgery Vol IV, Issue 1, 1988, and on the Video Journal of Ophthalmology, Vol IV, Number 4, 1988. It is also in the ASCRS Film Festival Library 1987 and 1991, and in the ESCRS Video Library, 1999. If none of these are available to you, please feel free to contact me at my office in Garden City, Kansas, for a Video of the procedure.

INTRODUCTION

Current surgical techniques used in cataract surgery have two fundamental objectives: (i) to induce the minimum postoperative astigmatism, and (ii) to achieve rapid recuperation of the patient’s sight after surgery.

To meet these objectives, it is necessary to perform cataract surgery using a small incision. It has been shown that the smaller the surgical incision, the smaller the residual postoperative astigmatism.

Of all the techniques described for cataract operations, phacoemulsification is the one that allows working with smaller incisions. However, it is a technique which requires a long learning curve, with expensive and complicated instrumentation and equipment.

Our manual multiphacofragmentation (MPF) technique allows cataract surgery through 3.2 mm clear corneal or 3.5 mm scleral tunnel incisions. In this method the nucleus is fragmented into multiple tiny pieces of 2 × 2 mm.

The method enables cataract surgery in soft and hard nuclei. The results obtained in postoperative astigmatism are similar to those obtained with phacoemulsification, but with a shorter learning curve and less financial outlay.

On the other hand, our method is an ideal back-up after discontinuation of emulsification when complications arise in phacosurgery, since with the help of our instrument set, we can conclude the surgery without enlarging the incision.

We designed an instrument set, manufactured by John Weiss and Son Ltd in England, which consist of

•A racquet-shaped nucleotome 8 mm long and 2 mm wide, divided along its short axis by 3 thin

Francisco J Gutiérrez-Carmona (Spain)

Figure 5.1: Nucleotome with a racquet-shaped end

transverse bars 2 mm apart, set at 45 degrees to a long straight handle (Figure 5.1)

•A spatula 8 mm long by 2 mm wide the same shape as the nucleotome, used as a support during the fragmentation (Figure 5.2)

•Two straight handled manipulators, right and left, used to collect the nuclear fragments (Figure 5.3).

SURGICAL TECHNIQUE

Surgical technique can be carried out with the use of retrobulbar or peribulbar anesthesia, topical or topical + intracameral anesthesia.

To perform MPF it is important to have good pharmacological mydriasis, since the pupil could contract during surgery.

Figure 5.2: Spatula with an end the same size as the nucleotome

Figure 5.3: Manipulators, right and left

Anterior Capsulotomy

High density viscoelastic is injected into the anterior chamber (AC) through a superior and temporal paracentesis, and a capsulorhexis is performed with a cystotome. It should be sufficiently wide (6.0-6.5 mm) to allow an easy luxation of the nucleus into the AC.

Incision

The surgery can be performed with a 3.2 mm clear corneal (Figure 5.4), or 3.5 mm scleral-tunnel incision (Figure 5.5).

The clear corneal incision is performed at 12 O’clock with a 45° stab incision knife and with the help of a disposable angled crescent knife. The scleral-tunnel

Figure 5.4: The 3.2 mm clear corneal incision is performed at 12 O’clock

Figure 5.5: The 3.5 mm scleral tunnel incision is made with the help of an angled crescent knife

incision is made after carrying out a fornix-based conjunctival miniflap about 2 mm posterior to the corneal-scleral limbus with the help of a disposable angled crescent knife, without penetrating the AC.

Hydrodissection and Luxation of the Nucleus

After entering the AC with a 3.2 mm phaco knife, balanced salt solution (BSS) is injected through the incision with a Binkhorst cannula between the anterior capsule and the cortex at 12 O’clock, or with a straight Rycroft cannula. The BSS must be injected slowly and continuously until the “wave of dissection” is visible on the posterior capsule.

Figure 5.6A: Pressing the nucleotome (on top) against the spatula

Figure 5.6B: Pressing the nucleotome (on top) against the spatula (beneath) the nucleus is fragmented

The injection of BSS is continued until luxation of the nucleus in the AC is partial. Then, it can be completed by rotating the nucleus with a cannula, cystotome or spatula.

Nuclear Fragmentation

Once the nucleus has been luxated into the AC, highdensity viscoelastic (Viscoat, Amvisc Plus, etc.) is injected into the surrounding area to fill the AC. The nucleus is then fragmented by placing the spatula beneath and the nucleotome on top of the nucleus (Figures 5.6A and B). Pressure is then created by slowly pressing the nucleotome against the spatula, until this section of the nucleus is fragmented into four pieces

Figure 5.7: The nuclear fragments within the nucleotome are extracted with a sandwich technique

which remain within the nucleotome, and which, with the help of the spatula, are extracted from the AC with a “sandwich” technique (Figure 5.7). This maneuver is repeated until all the nucleus is fragmented.

During nuclear fragmentation, it is important to fill the AC with high-density viscoelastic, as needed, to protect the corneal endothelium and to facilitate safe manipulation during surgery.

Manipulation of Nuclear Fragments

The right and left manipulators are used to displace the remaining fragments of the nucleus to the center of the AC for further fragmentation and extraction (Figure 5.8).

Extraction of the Cortex and Remains of Nucleus

The lens cortex is aspirated with an I/A Simcoe cannula. If tiny pieces of the nucleus are left in the AC, it is sometimes possible to remove them using only the nucleotome. Otherwise they can be extracted by the nucleotome and spatula, by aspiration with a Simcoe or Charleux cannula, or by gentle irrigation of the AC with BSS using a Rycroft cannula while simultaneously depressing the posterior lip of the incision.

IOL Implantation and Wound Closure

High-density viscoelastic is injected into the capsular bag and a foldable IOL is implanted (Figure 5.9). The viscoelastic material is then aspirated with an irrigating/aspirating cannula. Closure of the incision is performed with stromal hydration, or with a single cross-stitch (Figure 5.10).

Figure 5.8: Right manipulator displacing a nuclear fragment toward the center of the anterior chamber

Figure 5.9: A foldable lens is implanted in the capsular bag

We recommend to ophthalmologists who are new to this technique that they initially practise it using incisions of more than 3.2 or 3.5 mm and thereafter reduce the incision size once they have mastered the technique.

Lately I have been performing some steps of my technique with the help of an anterior chamber maintainer (ACM): model Lewicky 20 G from Katena or the ACM 20 G from John Weiss Ref. 0185061.

The ACM works by producing a constant irrigation flow of BSS into the AC. This flow generates a positive intraocular pressure (IOP) that stabilizes the AC depth during some steps of the surgery. On the other hand, with the ACM the quantity of viscoelastic

Figure 5.10: A single cross-stitch is enough to close the wound

material used persurgery is reduced, diminishing the financial outlay.

The ACM is used

•During the capsulorhexis

•In order to aspirate the anterior cortex and epinucleus in soft and medium hard nuclei before the hydrodissection/hydrodelineation

•For the aspiration of cortical debris

•For the extraction of tiny nuclear fragments, by depressing the posterior incision lip with a straight cannula.

The maneuvers of nuclear multifragmentation and IOL implantation are carried out with the help of high density viscoelastic material.

BIBLIOGRAPHY

1.Cristobal JA, Minguez E, Ascaso J, et al. Size of incision and induced astigmatism in cataract surgery. J Fr Ophthalmol. 1993;16:311-4.

2.Gutiérrez-Carmona FJ. Manual technique allows for small incision cataract surgery. Ocular Surgery News: Surgical Maneuvers 1997;15(21):14-5.

3.Gutiérrez-Carmona FJ. Manual technique allows for small incision cataract surgery. Ocular Surgery News (International Edition): Surgical Maneuvers 1998;9(2):10-11.

4.Gutiérrez-Carmona FJ. Nueva técnica e instrumental de facofragmentación manual para incisiones esclerales tunelizadas de 3.5 mm. Arch Soc Esp Oftalmol 1999; 74:181-6.

5.Shepherd JR. Induced astigmatism in small incision cataract surgery. J Cataract Refract Surg 1989;15:85-88.

6.Uusitalo RJ, Ruusuvaara P, Jarvinen E, et al Early rehabilitation after small incision cataract surgery. Refract Corneal Surg 1993;9:67-70.

I started to use the manual phacofragmentation techniques around 1993. Initially, I had begun with the Blumenthal Mininuc technique and later I also used the Kansas technique, but I found that working in the anterior chamber with large instruments was awkward and clumsy. I wanted to reduce the large size of the incision and I began to use the Handle technique of Keener, modified by Quintana, using a nylon handle instead of a steel one. Finally, in 1995 I began to use the Nagahara chopper and a Barraquer vitreous spatula to divide the nuclei in the anterior chamber. Initially I divided it in two pieces, later in three and four pieces, and finally in multiple fragments.

I had developed a manual phacofragmentation technique carried out in the anterior chamber using a chopper and a spatula. I called this technique the “Chop-Section Technique”, that is Chop-Bisection, Chop-Trisection or Chop-Multisection, as the nucleus is cut into two, three or more fragments. According to the number of fragments that we divide the nucleus into, and depending on their hardness and size, we are able to make an incision from 6 mm (Chop-bisection in very hard and big nucleus) to 2.8 mm (by means of Chop-Multisection in a nucleus of any degree of hardness).

To take away the fragments I used hydro, viscoexpression, a vectis, and finally the same chopper and spatula that I used to divide the nuclei. I called this technique the “Chopsticks Technique”.

The instruments to carry out this technique are available in any set of instruments for phacoemulsification.

•Chopper: I use a “Nagahara”, but any chopper can be used. It is advisable that the chopper has a cutting angle between 30 and 45º to facilitate the section and the fracture of the nucleus.

•Spatula: I use a Barraquer vitreus spatula, because it gives better control ot the nucleus during the section.

I have designed a chopper and a spatula to make the technique easier. Rumex international has made the second prototypes and I hope that soon the final product will be in the market (Figure 6.1).

Figure 6.1: ChopMultisection surgical prototypes made by Rumex International: (from right to left) spatula for hard nuclei, spatula for medium and soft nuclei, and arcuate chopper

SURGICAL TECHNIQUE

Preoperative Management

We use sodium Ciclopentolate and Phenilephrine drops to dilate the pupil, and non-steroid anti-inflammatory drops. During the manipulation in the anterior chamber miosis may take place, however this doesn’t affect phacofragmentation as we are working above the pupil. During irrigation-aspiration (IA) we can recover mydriasis, using an adrenaline infusion.

Anesthesia

This technique can be carried out under different types of anesthesia according to surgical experience and the degree of the patient collaboration. Once you are experienced in carrying out the technique, Topical anesthesia (1 drop three times every 5 min. 15 min. before the surgery) with Intracameral Lidocaine 0,75%, would be the best.

Incision

In three planes. We carry out a temporal (or on the sharpest curved meridian in case of astigmatism) blueline pre-incision in the sclerocorneal limbus. We adapt the preincision size to the technique that we will use, 4.5-6 mm for the Chop-Bisection, 3.5-5 mm for the Chop-Trisection and 2.5 to 4.2 mm for the ChopMultisection. If necessary, once the nucleus is broken into fragments, we can enlarge the incision to the desired size, maintaining its shape.

Capsulotomy

We carry out a capsulorhexis (CCC) with a cystotome or with Corydon forceps through the paracentesis or the incision. This capsulorhexis should be sufficiently wide (approximately 5.5 to 6.5 mm.) to allow the easy luxation of the nucleus to the AC. Even if you do not reach the CCC, you can still continue with the same technique.

Hydrodissection and Luxation of the Nucleus

Once the CCC is reached, we inject a balanced saline solution (BSS) between the anterior capsule and the córtex at 3h using a Charleux or Rycroft 27G cannula through the incision.

We inject the BSS gently in order to get the hydrodissection, we then hydrodelineate the hard nucleus and separate it from the epinucleus. We aspirate

Figure 6.2: Lateral view of the chopper and spatula

the cortex over the hard nucleus, we luxate it to the AC using cannula or viscoelastic, leaving the epinucleus in the capsular bag, in order to free up space in the AC.

Nuclear Fragmentation

Once the hard or primitive nucleus has been luxated to the AC, we inject high density viscoelastic around the nucleus filling in the AC. We introduce the Barraquer vitreous spatula between the nucleus and the posterior capsule and then the chopper between the cornea and the nucleus (Figures 6.2 to 6.5).

Then we continue with the Bisection/Trisection/ Multisection, cutting with the chopper from 6h to 12h,

Figure 6.3: Chopper slidding directtion and angulation between both instruments

Figure 6.4: Instruments position

Figure 6.5: Breaking force towards 3 and 9 h at the end of the cut

creating counter pressure with another instrument, like the Barraquer spatula. In the Trisection we carry out a second incision parallel to the first one (Figures 6.6 and 6.7). In the Multisection we carry out as many incisions as necessary, until we obtain the desired size of nuclear fragments. An angle of about 40º should be maintained between both instruments in order to avoid vertical movement of the nucleus. In the final part of the trajectory section, we separate each of the instruments one to 3h and the other to 9h, to fracture the nucleus (Figures 6.8 and 6.9). Once divided, we adjust the final size of the incision (2.8 to 6 mm) in relation to the size and hardness of the fragments obtained.

Figure 6.6: Cracking the nucleus (Chop-Bisection)

Figure 6.7: Paralel cuts can be made to get 3 (Choptrisection) or more fragments (Chopmultisection)

Extraction of the Cortex and Nucleus Remained

The internal lip of the incision should be larger than the external one, creating an exit type cone that facilitates the exit of the nuclear fragments. Their extraction may be carried out by means of hydro or viscoexpression, with the help of a vectis (Figure 6.10), with the sandwich technique, or using the Dr. Gutiérrez Carmona nucleotome and his spatula. These are very useful for very hard nuclei or in those with sharp edges.

In nuclei of medium to high hardness we pinch together the fragments laterally using the spatula and the chopper which hold the fragments (Figure 6.11).