"Nucleuscapture"
a new aid or an alternative to phacoemulsification

INTRODUCTION

Small-incision cataract surgery is the state-of-the-art for a faster and satisfactory visual rehabilitation. Regardless of whether this goal can be reached with or without phacoemulsification the important factor is, in our opinion, that each surgeon should attain confidence with both procedures considering the following:

- By employing phaco technique one can use very small tunnels and implant foldable or new microfoldable IOLs;

-On the other hand many surgeons look with interest to acquire the advantages of small-incision procedure without the long and risky learning curve, high cost and complexity of phacoemulsification.

Since 1991, after hearing and reading about McIntyre Kansas, Rozakis and Fry techniques, we have brought significant modifications to their procedures and so we have achieved and inexpensive, phacoless, easy repeatable technique than enables us to perform sutureless tunnel-incision cataract surgery with good control and planned reduction of pre-existing astigmatism.

In the following pages we give an exhaustive account of our surgical procedure that we have performed up to now in 1250 cases with an average follow-up of 2 years.

SURGICAL PROCEDURE

Congiuctival flap – When a sclero-corneal tunnel is planned, a small conjuctival flap is dissected directly with the same diamond blade by which a straight pre-incision has been made, most frequently at 1.5 mm from the temporal limbus.

Incision – The incision is made at the axis of the greatest corneal curvature as determined by pre-operative keratometry in order to reduce pre-existing astigmatism.

For the years 1991-92, in approximately 150 cases, our technique has involved phacoless extraction through a tunnel length of 6.5, 6.0 and 5.2 mm in different shapes. In 1991 and 1992, before passing to the today routine of a straight nostitch tunnel, we performed a one-stitch modified Masket suture.
Since 1993, and with the current version of our technique, we do not place any suture for tunnel placement and width is determined by the amount of pre-operative corneal astigmatism, as shown in the following nomogram derived from follow-up of first 400 cases (tav.1).

Tunnel Location and Size – When pre-operative astigmatism is lowe than 0.75 D with-the-rule, we usually place the no-stitch tunnel 1.5 mm.. from the temporal limbus, while in cases of preoperative against-the-rule astigmatism we prefer a no-stitch clear-corneal temporal tunnel. In cases of with-the-rule astigmatism higher than 0.75 D the tunnel is placed superiorely at this axis of greatest curvature as shown in the nomogram.

Tunnel Sculpting – After a wet-field cauterization, with a diamond knife we make a straight incision at a planned distance from the limbus of approximately one-half thickness. With Nucleuscapture no side-port incision is required.

The groove, the complete tunnel carving of 1.5 mm. in clear cornea and the entry into anterior chamber, are all made with a 3.2 mm. angled slit knife. A sideways sawing motion with the knife helps to wide the tunnel to the predetermined dimension under calliper control. In case of a planned 5.2 mm. tunnel, a 5.2 mm. angled slit knife is used.

Anterior Continuous Circular Capsulorhexis – Viscoelastic material is injected into the anterior chamber and with the use of forceps, a continuous circular capsulorhexis is made (A.C.C.C.).

Capsular Hydrodissection – Using a 27 ga.needle a capsular hydrodissection is performed lifting the edge of the capsulorhexis at the distal border, softly forming a tentlike space beneath the capsule and avoiding touching the cortex. Next, balanced salt solution is continuously injected untile there is evidence of a complete posterior capsule dissecting wave. At this point the nucleus is pushed down using the same 27 ga.needle for a complete proximal dissection. The needle immediately startsa a cortical straight sculpting until reaching the inner epinuclear plane, in wich balanced salt solution is injected peripherally and in a quick mode so to obtain the golden ring reflex of hydrodelineation. In most cases central anterior cortex is then aspirated with a common o.5 I/A tip of better visualization of capsulorhexis and to form a cleaving plane to facilitate the internal Nucleuscapture. Hydrodelineation is further performed in the posterior nuclear space and completed with viscoelastic material. Next, the inner nucleus can be hooked up and rotated in the anterior chamber. This manoeuvre can be facilitated by the use of  a nucleuscapture hook manufactured under our own specifications.

Nucleuscapture – Freeing the inner nucleus from all cortical material with a viscoelastic substance, enables the introduction of the specifically designed instruments: nucleuscapture spoon beyond the nucleus, slipping on the posterior cortex and a small hooked nucleuscapture spatula that is placed on top of the nucleus sandwiching is between the spoon and spatula.

The nucleus is so captured and extracted with a two-hand technique and delivered through the tunnel with a real two-hand control of the procedure and in true single manoeuvre. Occasionally, especially in small tunnels or in hard nuclei, the anterior portion of the nucleus will be sheared off with this technique, but usually this epinucleus is nearly always soft and easily aspirated with a 0.5 mm. and next with a 0.3 mm. I/A tip. Most of the retained epinucleus will usually irrigate out through the tunnel and will not require aspiration. Thanks to capsular hydrodissection, the cortex is quickly aspirated using the automated 0.5 mm. / 0.3 mm. tip. Since 1994, following Gills, Galand and Philipson indications, we are satisfactorily performing a posterior continuous circular capsulorhexis (P.C.C.C.). By March 1996, we have reached quote 600 posterior capsulorhexis procedures with reliable results.

IOL Implantation – After injection of some other viscoelastic material, IOLs of 5 or 5.5 optic and 12 – 13 mm. overall diameter are implanted. The procedure to ensure implantation in the capsular bag can be facilitated by using a straight pusher to guide the IOL proximal loop into the bag avoiding touch with any surrounding tissue.

After removal of viscoelastic material the self-sealing effect of the tunnel incision is tested by inflating the anterior chamber with balanced salt solution through the tunnel itself. As IOP reaches the normal range, pressure within the eye will work just to close the wound. Since 1993 we have not used sutures anymore.

Closure of the Conjunctival Flap – When planned the conjunctival flap is closed with bipolar wetfield cautery.

In our experience we have never encountered a nucleus that was impossible to squeeze out although a rare few have required a fair amount of manipulation especially in the first year.

At present, a great number of surgeons use planned extracapsular cataract extractgion as their procedure of choice. Those surgeons who routinely use phacoemulsification will frequently deal with very hard nuclei or small pupils in wich they wat to do a planned extracapsular extraction. Nucleuscapture works well in all pupil sizes and in all types of nuclei. Luxated cataracts are a relative contraindication however, in one case, we have used nucleuscapture to remove a dislocated

Lens from the vitreous intracapsularly through a 8 mm. scleral temporal tunnel.

Complications Management – Complication that can be encountered with nucleuscapture is a non-intentional breaking of the inner nucleus into two pieces while attempting to extract it from the eye. The situation is handled quite easily by rotating the residual portion of the nucleus with the spatula so that it is oriented along the surgical meridian and repeating the manoeuvre.

Brunescent nuclei can be removed through a 6.5 mm. tunnel following neucleuscapture.

In the case of planned 5.2 mm. tunnel the removal is accomplished by purposely breaking the inner nucleus into two pieces and removing them separately following the McIntyre/Kansas technique.

CONCLUSIONS

In developing this technique of nucleusreduction accomplished with a true single manoeuvrfe of nucleuscapture, rather than multiple manoeuvres of nucleus splitting, one of our concerns was the effect on the endothelium of  pulling the inner nucleus throughout the trunnel. In the beginning, we had expected to see as strip of damaged endothelium at the surgical limbus but this has never been noted. This thanks, maybe, to the following factors:
- the main pressure of the nucleus appears to be at the edge of the external tunnel wound and not anteriorely on the cornea,
- the single-manoeuvre by which, in our technique, we obtain the nucleuscapture.

Following this guideline, we underline once again that nucleuscapture is not a nucleusreduction

Accomplished with nucleus splitting (such as in McIntyre-Kansas manoeuvres in which the surgeon must enter the anterior chamber with the instruments at least 2 or 3 times, determining consequently and higher endothelial cells damage), but a nucleusreduction accomplished with a true single manoeuvre of nucleuscapture with, therefore, a critical and important less endothelial damage with a much better appearance of post-op corneas since the day after surgery. As a matter of fact, in our experience the appearance of post-op cornea was somewhat better than in cases done with two-handed phacofraction as revealed by evaluation of endothelial cell count in 40 follow-up cases at one month after surgery.

Our experience with nucleuscapture has been that planned sutureless tunnel incision not only appears to control or reduce preoperative astigmatism but, also, appears to be more stable than those with any type of suture used in the past. With the no-stitch self-sealing tunnel we have found deeper anterior chambers and less hyphema.

Patients experience no foreign body sensations due to the absence of sutures and the great majority of them can be dismissed from the hospital one day post-op without shield and they can immediately resume rigorous activity. Patients, surgeon and patient-care personnel are equally pleased with the results of nucleuscapture technique described here.

Acknowledgement

• Blumenthal M, Mini-nuc technique for ECCE reduces tunnel size, Ocuklar Surgery News Internatyional edidion, march 1996
• Castaneda V., Posterior continuous curvilinear capsulorherix. An experimental study with Clinical applications, Ophthalmology 99.45-50, 1992
• Fichman R.A., A strategy for management of astigmatism in the small incision cataract patient, Ocular Surgery News International edition, July 1994
• Fine H, New cataract techniques, Clear corneal temporal incision presented at 1992 meeting, Welsh cataract congress Houston and congress of the European Society of cataract and Refractive Surgeons-Paris 1992.
• Galand A.., Posterior capsulorhexis in uncomplicated adult eyes, Ocular Surgery News International edition, 28, December 1993.
• Galand A., Posterior capsulorhexis in adult eyes with intacrt and clear capsules, J. Cataract Refractive Surgery,  vol.22. May 1996.
• Giannetti R., Nucleuscapture a safe inexpensive option for small incision cataract surgery, Ocular Surgery News International edition 1, 14-15. March 1996.
• Giannetti R., Phacoless Nucleuscapture through a planned location no-stitch tunnel, Ocular Surgery News American edition, 1,38-39. April 1996.
• Gimbel H.V., Posterior capsulorhexis with optic capture maintaining a clear visual axis after pediatric cataract surgery, J.Cataract refractive surgery, vol.20, 658-664. November 1994.
• Gimbel H.V., Continuous circular two staged and posterior continuous circular capsulorhexis, Ophthalmic pract 8,2, 81-85. 1990.
• Kansas P., Phacosection Manual small incision cataract surgery, International Ophthalmology Seminars 747 Madison Avenue-Albany NY 1996.
• Kansas P., Phacosection manual small incision no-stitch nuclear phacofragmentation, Ocular surgery News International edition, July 1992.
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• Mc Intyre D., Nucleus fracture through a 6 mm frown incision, Ocular Surgery News International edition, November 1996.
• P.O.R.T. study: National outcomes of cataract extraction incidence of retinal problems, following YAG capsulotomy, Johns Hopkins Med.Institution, Ophthalmology, October 1992.
• Rozakis G., Alternative small incision techniques, Slack incorporated Thorofare NJ 1990.
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• Thornton S., Astigmatism Nomogram for quantitative surgery, Small incision cataract surgery, Gills-Sanders 245-258, Slack incorporated Thorofare NJ 1990.
• Zetterstrom C., Cataract surgery in children with capsulorhexis of anterior and posterior capsule, J.Cataract refractive surgery, vol.20, November 1994.

(From Point of View International Ophthalmic Journal)