Complicated pars plana vitrectomy accomplished under topical anesthesia

Pre-rolled foldable lenses were sutured into place in lengthy procedures, all well-tolerated by the patient.

In six instances, I have been called on to intervene intraoperatively in cases of planned topical anesthesia phacoemulsification, with pre-rolled posterior chamber IOL implantation by means of a clear corneal incision. Two of these cases are presented below, in which unplanned full pars plana vitrectomy, intravitreal phacofragmentation and suturing of a pre-rolled posterior chamber lens were accomplished under topical anesthesia.

Case 1

---The MemoryLens in its delivery system where it is easily accessible to be prepared for suturing.

In the first case, a 4+ nuclear sclerotic cataract began to unzip its zonules nasally without dislocation in the left eye of a 72-year-old highly compliant white female during phacoemulsification through a temporal clear corneal incision. Anesthesia had been accomplished by means of topical 4% Marcaine (bupivacaine HCl; Abbott) and intracameral 1% preservative-free Xylocaine (lidocaine HCl injection, USP; AstraZeneca LP). Surgery was halted by the surgeon and I was called in on an emergency basis to assist in removing the cataract and securing a pre-rolled MemoryLens (CIBA Vision, Duluth, Ga.) by means of a posterior approach. The patient's eye appeared to be well anesthetized and a decision was made to proceed without additional retrobulbar block based on a previous report of a successful topical anesthesia vitrectomy.

The first step was to secure a posterior infusion line and pressurize the eye, since it was quite soft and, therefore, difficult to perform a routine vitrectomy setup. Partial-thickness scleral flaps were made to allow coverage of the suture knots at the end of the surgery. Working sclerotomies were placed in the bed of the flaps 180º apart (at the 10:30 and 4:30 positions) with the infusion cannula placed inferonasally to avoid obstruction of a working hand by the nose. These sclerotomies were made 1.5 mm posterior to the limbus to allow fixation of the implant just behind the iris. The lens nucleus was then totally dislocated onto the macula with the vitrector, followed by full vitrectomy to relieve all vitreoretinal traction. Mid-vitreal phacofragmentation of the nucleus was performed.

Next, a MemoryLens (a pre-rolled IOL composed of a hydrophilic material with 4-0 polypropylene haptics) was prepared for suture fixation. While the lens was still in its delivery system, knobs at both ends of the haptics were formed by melting with an OpTemp handheld cautery. This prevents overt slip-page of the sutures that might occur in postoperative trauma. A small knick in the haptic at its distal end from the optic was performed with a Beaver blade. Single-armed 9-0 polypropylene sutures were then tied to the haptics with the knots cinched down into the knicks to prevent slippage.

Both suture needles were then inserted through the corneal incision and back out through the sclerotomies at the 10:30 and 4:30 positions. The MemoryLens was then inserted through the corneal incision and under the iris with forceps. The sclerotomies were closed with the same 9-0 polypropylene by means of a self-tying knot, which also fixated the implant after centration. The scleral flaps were then laid down over the knots. At 11 days postop, the patient was 20/40 with some dry macular degeneration.

Case 2

The second case was similar except that during phacoemulsification, the lens nucleus was dislocated into the vitreous prior to emergency consultation. The patient was a relatively high-strung 54-year-old white female pediatrician. Phacoemulsification was being performed through a 12-o'clock scleral tunnel. There was retained capsule infer- iorly between the 5-o'clock and the 9-o'clock positions. Routine three-port vitrectomy at the 9:30, 2:30 and 4-o'clock positions was performed, followed by intravitreal phacofragmentation of the nucleus.

It was decided to secure the lens at the 1-o'clock position by means of a sclerotomy 1.5 mm posterior to the limbus with a partial-thickness scleral flap. This was to avoid the pre-existing scleral tunnel at the 12-o'clock position and to be 180º from the position of the residual inferior capsule. In this case, the lens was secured with only one 90 polypropylene suture superiorly, with the inferior haptic sitting in the ciliary sulcus on top of the residual anterior capsule. Once again, a pre-rolled MemoryLens was used, allowing insertion through the very limited opening. The patient's postop visual acuity at 2 months was 20/20.

Findings

I have found that suture fixation is required only when there is not enough anterior capsule on which to rest both haptics 180º apart in the ciliary sulcus. When there is only a limited amount of capsule remaining, I have found that one-point suturing is all that is required, 180º away from the residual inferior capsule. When there is no capsular support, two-point fixation is required. Whenever possible, the same sclerotomies should be used to perform the vitrectomy and fixation.

My experience has shown the pre-rolled MemoryLens to be considerably easier to prepare for suturing than other folded IOLs that I have used. The lens is stored cooled and slowly unrolls in the warm intraocular environment. Since there is no special instrument or inserter needed, I have been able to prepare the lens in its original holder. The lens does not jump or flop around, and the haptics are accessible.

I believe these two cases illustrate what is possible under topical an-esthesia. The first case took 1.5 hours and the second case took 1 hour.

Occasionally, I would notice some minimal pulling of the eye during the surgery, but this was insignificant and could be easily control-led with the instruments. In fact, at certain times, especially during manipulation of the sclerotomies and sutures, the patient was asked to look in a certain direction to facilitate exposure.

Patient tolerance was excellent, even with the second patient who might be considered a type-A personality.

For Your Information:

• Marc A. Lowe, MD, in solo private practice with a focus on retina and vitreous, is also an assistant clinical professor at University of California at Los Angles Jules Stein Eye Center. He can be reached at 2320 Bath St., Ste. 300, Santa Barbara, CA 93105; (805) 682-4761; fax: (805) 682-4211; e-mail: laserdoc@lasersighteyecare.com. Dr. Lowe has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any companies mentioned.