(USA)
INTRODUCTION
In this chapter, I would like to describe a small incision manual technique which I have used since 1985. It involves “sandwiching” the nucleus out between a lens loop and spatula. This technique uses an incision of 7.0 mm. It can be used with capsulorhexis or with any other type of capsulotomy, such as can-opener. This 7.0 mm “frown” incision is self-sealing in the majority of cases, and does not require a suture. This larger incision does give more astigmatic shift than a 3.0 mm phaco incision, however this can be of benefit if one operates on the steep axis of K.
This technique works as well with rock-hard nuclei as with soft nuclei. It can be done with inexpensive reusable instruments, and may be more appropriate than phaco in situations where finances are limited.
Topical anesthesia with intracameral lidocaine is used. I presently prefer 2 percent lidocaine gel. The 1 percent nonpreserved intracameral lidocaine seems to sting less if it is made-up by diluting 2 percent nonpreserved lidocaine 50/50 with BSS.
INCISION
A side-port is made with a 15° blade. A few tenths cc of 1 percent nonpreserved lidocaine are instilled (Figures 1.1 and 1.2). The eye is filled with viscoelastic through the side-port (Healon GV® is presently my preferred viscoelastic).3
An 8.0 mm peritomy is made with scissors and bleeding is cleared up with wet-field cautery (under topical anesthesia, this may cause a slight sting. This, and the 4cauterization closure of conjunctiva at the end are normally the only times the patient feels anything. The discomfort is minor, and not a problem if the patient is forewarned). A superior rectus suture is not used. The incision site is on steep axis of “K” for cylinder 1.0 diopter or greater. For less than 1.0 diopter cylinder, temporal approach is preferred. Deep set eyes are also approached temporally. A limbal relaxing incision opposite the incision is added for cylinder greater than 2 diopters (Figures 1.3 to 1.5).
A “frown” incision is made with a guarded diamond knife set at 0.25 mm. The incision is dissected forward into clear cornea with a bevel-up crescent blade (Figures 1.6 and 1.7). Superior incisions are dissected about 1.0 mm into clear cornea and temporal about 1½ mm into clear cornea (the initial groove can also be free-handed with either the crescent blade or other blade, I feel the guarded diamond gives a better and more reproducible groove).
The anterior chamber is entered with a 3.2 mm keratome at the depth of this scleral flap, giving a self-sealing internal flap. Additional viscoelastic is placed (Figures 1.8 and 1.9).
SMALL PUPILS
Small pupils are managed by stretching them out with two Kuglen hooks. One stretch, limbus-to-limbus, is all that is necessary. Additional stretches give little additional effect. Stretching slowly may help to avoid rupturing the sphincter.
Hold for a second or two at maximal stretch. Then expand the iris out with viscoelastic (Figures 1.10 to 1.13).
After pupil stretching, the pupil may be permanently larger than before, with crenated edges, particularly if it was very small and nondilatable preoperation. In these cases, it might be advisable to use a 6.0 mm or larger optic (I prefer 7.0 mm optics in all cases). This larger pupil is actually a benefit in allowing easier fundus viewing. I think you will be impressed by the ease and safety of this pupil stretching maneuver, and by the relatively normal appearance of the pupil postoperation.11
ANTERIOR CAPSULOTOMY
Any type of capsulotomy works well with this procedure. I prefer a capsulorhexis. The capsulorhexis, however, needs to be made as large as possible to allow nucleus tip-up. A can-opener capsulotomy works well also and is used if there is difficulty with the capsulorhexis. For mature cataracts, capsular staining under an air-bubble with either ICG or Trypan Blue (Vision Blue®, from Dutch Ophthalmic) makes the capsulorhexis much easier (Figures 1.14A to D).
I prefer a Gimbel Utrata forceps for the capsulorhexis. This forceps has sharp tips so the capsule can be penetrated and the rhexis completed without changing 13instruments. I start in the middle and spiral out. Re-deepen with viscoelastic anytime the tear wants to “head south” (Figures 1.15 and 1.16).
HYDRODISSECTION
Complete hydrodissection is done, with the cannula just beneath the anterior capsule, to loosen the nucleus and get it rotating freely. Generally one fluid wave to the right and one to the left will be adequate. I like to use a spatula through the side-port and the hydrodissection cannula through the incision to bimanually rotate the nucleus after hydrodissection (Figure 1.17).
NUCLEUS DELIVERY
After capsulotomy, the 3.2 mm incision is enlarged to 7.0 mm. I find that a 5.2 mm keratome works best for this. The crescent blade also works fairly well. Attempt to maintain the internal self-sealing incision all the way across (Figure 1.18).
The chamber is refilled with viscoelastic. A Kuglen hook in the left hand nudges the nucleus gently away from the incision. The spatula catches the superior pole of the nucleus at the equator and tips it up. Using the two instruments, the nucleus is then cartwheeled through the capsulorhexis and pupil (Figures 1.19 to 1.22) into the anterior chamber (as an alternative, it may be “somersaulted” end-over-end into the anterior chamber).
FIGURE 1.19: Nudge nucleus away from incision with spatula, retract capsulorhexis edge slightly with Kuglin hook
If nucleus tip-up is difficult, aspirate the cortex off the top of the nucleus with the 0.3 IA tip, refill with viscoelastic, and attempt tip-up again.
Additional viscoelastic is placed beneath the nucleus. The lens loop is placed beneath the nucleus and the spatula on top. The nucleus is extracted, “sandwiched” between the two instruments. The outer portion of the nucleus will be sheared off with this technique, but it is soft and easily aspirated or irrigates out of the self-sealing incision with gentle pressure on the posterior wound lip (Figures 1.23 to 1.26).
If the nucleus breaks in two during removal, rotate the residual fragment so it is oriented with its long axis perpendicular to the incision. Add additional viscoelastic to blow the iris back and resandwich it (Figures 1.27 to 1.29).
Large brunescent nuclei may be extracted through a 7.0 mm incision by purposely breaking off a superior wedge, then rotating 90° and removing. This is done by placing the lens loop and spatula one-third of the way down the nucleus and pinching off a fragment, reducing its diameter. Then, rotate long axis perpendicular to the incision and sandwich (Figures 1.30 to 1.33).
CORTEX ASPIRATION
Cortex is aspirated with the technique of your choice. I prefer automated technique with 0.3 IA tip. Manual technique also works well. If there are damaged zonules or a break in the capsule, I go to a “dry” technique, with manual cortex aspiration with a 27 gauge cannula on a 3 cc syringe under viscoelastic. A noncohesive viscoelastic, such as Viscoat, works better in this situation than Healon. A Morcher capsular support ring is helpful in cases with damaged or absent zonules.
A safety suture is not necessary. If there is a tendency to iris prolapse, this usually means a self-sealing incision has not been obtained and an “X” suture will be required at the end of the case. Residual epinucleus can be washed out of the wound by slightly depressing the posterior lip while irrigating with the IA tip. This is somewhat more efficient than aspirating epinucleus. Stubborn cortex can be assisted into the 0.3 IA tip with the “potato masher” maneuver (Figure 1.34).24
Subincisional cortex can be more easily removed by splitting irrigation and aspiration and inserting the aspiration cannula through the side-port (Figure 1.35). These instruments and adaptor are available fairly inexpensively from ASICO (Table 1.1).
Viscoelastic is used to expand the capsular bag. A 7.0mm lens fits snugly through the incision. If squeezing is required, hold the eye with the closed 0.12 forceps inserted into the side-port (holding the flap risks tearing it). Insert the leading loop of the lens first, then the optic to avoid loop crimping (Figures 1.36 to 1.38).
Aspirate viscoelastic. The internal flap is sealed by pressurizing the eye with BSS through the side-port. Blood in the wound gives a Seidel effect to demonstrate any leak.25
FIGURE 1.35: Irrigation through the incision and aspiration through the side-port for subincisional cortex
The chamber depth can also be observed to demonstrate no leak. If the chamber deepens with pressurization and does not shallow once the pressurization cannula is removed, self-sealing is indicated. This should occur in 95 percent of cases (Figure 1.39).27
Conjunctiva is brushed over the wound and sealed with wet-field cautery (Figure 1.40).
CAVEATS
This technique is viscoelastic-dependent. Be sure to have plenty of viscoelastic both in front of the nucleus and behind it when sandwiching. Attempting to remove the nucleus under air will result in striate keratopathy. This procedure does, however, work well with methylcellulose, or with any other viscoelastic.
When starting out, use a larger incision, possibly 8.0 mm; then gradually decrease the incision size as 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).29
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.