"Nucleuscapture"
a safe, inexpensive option for small-incision cataract surgery

Surgeons can obtain the benefits of a small self-sealing incision without the added costs of phaco.

Livorno, Italy – white phacoemulsification enables surgeons to use small incisions and implant foldable IOLs, manywould like to avoid the learning curve, high cost and complexity of the procedure. Riccardo Giannetti, MD, of the Hospital of  Livorno, has created a new technique, “nucleuscapture”, which he says is a less expensive, repeatable and relatively easy method of performing sutureless tunnel incision cataract surgery.

Dr. Giannetti placed the incision at the axis of greatest corneal curvature, as determined by preop keratometry, to reduce pre-existing astigmatism. Capturing, extracting and delivering the nucleus

Through the tunnel with a two-handed technique affords the surgeon great control of the procedure.

According to Dr. Giannetti the no-stich self-sealing tunnel has resulted in deeper anterior chambers and less hyphema. He also reports that, in 40 eyes at one-month postop, the appearance of corneas seems to the better than in  cases done with other methods of phacosection.

“Patiens experience no foreign body sensations due to the absence of sutures, and the great majority of them are able to go home one day postoperative without a shield and immediately resume rigorous activities,” he said. For more on the nucleuscapture technique, see page 14.

Phacoless “nucleuscapture” through a no-stitch tunnel incision appears to control astigmatism

By Riccardo Giannetti, MD Special to Ocular Surgery News

Small-incision cataract surgery is state-of-the-art for faster and satisfactory visual rehabilitation.

Regardless of whether this goal can be reached with or without phacoemulsification, the important

Factor, in my opinion, is that each surgeon should attain confidence with both procedures and consider the following:

-By employing phaco technology, one can use very small tunnels and implant foldable or new microfoldable IOLs.

-On the other hands, many surgeons are interested in acquiring the advantages of a small-incision procedure without the long and risky learning curve, high cost and complexity of phacoemulsification.

Since 1991, after reading and hearing about McIntyre, Kansas, Rozakis and Fry techniques, with my own modifications, I have achieved an inexpensive, phacoless, repeatable, relatively easy method of performing sutureless tunnel-incision cataract surgery with good control and planned

Reduction of pre-existing astigmatism.

Conjunctival 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 is constructed most frequently 1.5 mmfrom the limbus.

Incision

The incision is placed at the axis of greatest corneal curvature as determined by preoperative keratometry in order to reduce pre-existing astigmatism. For the past three years, in approximately

150 cases, my 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 routine, straight no-stitch tunnel, I had performed a one-stitch modified Masket suture.

With my technique, I do not place a suture for tunnel placement and width is determined by the amount of preoperative corneal astigmatism, as shown in the nomogram derived from follow-up

Of my first 400 cases.

Tunnel location, size and sculpting

When preoperative astigmatism is lower than 0.75 D with-the-rule, I usually place the no-stitch

Tunnel 1.5 mm from temporal limbus, while in cases of preoperative against-the-rule astigmatism

I prefer a no-stitch clear-corneal temporal tunnel.

In cases of higher than 0.75 D with-the-rule astigmatism, the tunnel is placed superiorly at the axis of greatest curvature as shown in the nomogram.

After a wet-field cauterization, a diamond knife is used to make a straight incision at a planned distance from the limbus of approximately one-half thickness. No side port incision is required with “nucleuscapture.”

The groove, the complete tunnel carving of 1.5 mm in clear cornea and the entry into the anterior chamber are all accomplished with the Alcon Duplicut 3.2-mm angled slit-knife: A sideways sawing motion with the Duplicut widens the tunnel to the predetermined dimension under caliper control; in case of a planned 5.2-mm tunnel,a 5.2-mm angled slit-knife is used.

Viscoat (chondroitin sulphate, sodium hyaluronate, Alcon) or Healon GV (sodium hyaluronate, Pharmacia) is injected in the anterior chamber, and a continuous circular anterior capsulorrhexis is

Made by employment of forceps.

Capsular hydrodissection

Using a 27-ga needle, a capsular hydrodissection is performed lifting the edge of the capsulorrhexis

At the distal border, softly forming a tent-like space beneath the capsule and avoiding touching the cortex. Next , balanced salt solution is continuously injected until 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 starts a cortical straight sculpting until reaching the inner epinuclear plane in which balanced salt solution is injected peripherally and quickly to obtain the golden ring reflex of hydrodelineation.

In most cases, central anterior cortex is then aspirated with a common 0.5 I/A tip for better visualization of capsulorrexis and to create a cleaving plane to facilitate the internal nucleuscapture.

Hydrodelineation is further performed in the posterior nuclear space and completed with Healon (viscodelineation).Next the inner nucleus can be hooked up the rotated in the anterior chamber; this

Maneuver can be enhanced by employment of the “nucleuscapture hook” manufactured under my own specifications.

Nucleuscapture

Freeing the inner nucleus from all cortical material with a viscoelastic enables the introduction of a small lens loop or the nucleuscapture spoon” beyond the nucleus, slipping on the posterior cortex: Then, a small hooked “nucleuscapture spatula” is placed on top of the nucleus, thus sandwiching it between the lens loop needle and spatula.

The nucleus is “captured” and extracted with a two-handed technique and delivered through the tunnel with a real two-hand control of the procedure. Occasionally, especially in small tunnels or hard nuclei, the anterior portion of the nucleus will be sheared off with this technique, but this “epinucleus” is nearly always soft and is easily aspirated with first the 0.5 mm and next the 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/0.3mm tip.

IOL Implantation

Viscoelastic material is injected in the capsular bag. I have used Healton, Viscoat and Occucoat (hydroxypropyl methylcellulose, Storz); all appear to work well but my preference is Viscoat for capsulorhexis maneuvers and Healon for all other procedures.

Implanted IOLs were mainly Allergan AMO PC52ANB – an extremely flexible PMMA IOL with a 5-mm optic and 12-mm overall diameter.

Also frequently employed was the Allergan AMO PC 43NB, with a 5.5-mm optic and 12-mm overall diameter. In cases involving large tunnels, the Allergan AMO PC59TB may be suitable for in-the-bag capsulorrexis implantation despite the overall 13.5-mm diameter, due to the extreme flexibility of the loops.

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 to any tissue.

After viscoelastic material is removed with the same I/A tip, 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, I have not placed sutures to close the incision.

Closing conjuctival flap

When planned, the conjunctival  flap is closed with bipolar wet-field cautery. I have never encountered a nucleus that was impossible to squeeze out, althougth a rare few have required a fair amount of manipulation especially in the first year.

A great number of surgeons at present use planned extracapsular cataract extractioin as their procedure of choice.

Those surgeons who routinely use phacoemulsification will frequently deal with very hard nuclei or small pupils in which they want to do a planned extracapsular extraction.

Nucleuscapture works well for all pupil sizes and all types of nuclei.

Luxated cataracts are a relative contraindication, however in one case I have used nucleuscapture to remove a dislocated lens from the vitreous intracapsulary, sandwiching the lens between the two instruments to extract it from the eye across a temporal 7.5-mm no-stitch large sclero-corneal tunnel.

Managing complications

A complication that might 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 maneuver.

Brunescent nuclei can be removed through a 6.5-mm tunnel following nucleuscapture. In the case of the 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.

In developing my procedure, one of my concerns was the effect on the endothelium of pulling the inner nucleus throughout the tunnel. I had expected to see a strip of damaged endothelium at the surgical limbus. However, this has not been noted, for the main pressure of the nucleus appears to be at the edge of the external tunnel wound and not anteriorly on the cornea.

In my experience, the appearance of postop corneas was also 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.

My experience with nucleuscapture has been that planned sutureless tunnel incision not only appears to contro of 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, I 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 are able to go home one day postoperative without a shield and immediately resume rigorous activities. The patients, surgeon and patient-care personnel are equally pleased with the results of nucleuscapture described here.

Special thanks to Prof. P.A. De Napoli, MD, for his valuable contributions.

Riccardo Giannetti, MD, is attending surgeon at the department of ophthalmology, Hospital of Livorno (Italy).

(From Ocular Surgery News international edition, vol.7 number 3, March 1996)