Posterior Lip Sclerectomy Research Articles

Wound healing after filtering surgery in owl monkeys.

We performed posterior lip sclerectomies in 29 owl monkey eyes to determine the natural history of wound healing after filtering surgery without adjunctive antimetabolite therapy. We noted three phases of wound healing during clinical and histologic examination: early healing (days 2 to 6), intermediate healing (days 7 to 9), and late healing (days 10 to 14). In the early healing phase, all limbal fistulas except one remained open gonioscopically, but by day 6, fibroblasts had proliferated along the walls of the opening. Proliferation and migration of fibroblasts continued during the intermediate healing phase to completely occlude four and to partially occlude two of the ten fistulas in the eyes studied during this time. In the late healing phase, the limbal fistula was completely closed by granulation tissue in four of five eyes and was slitlike open in one eye. In this model of filtering surgery, wound healing at the sclerectomy site with obliteration of the limbal opening by proliferating fibroblasts occurred within the first 14 postoperative days. We believe that the short-term effects of newer treatments designed to alter wound healing after filtering surgery may be assessed in this model, which is characterized by predictable and prompt wound healing.

The Use of Glaucoma Shell Tamponade in Leaking Filtration Blebs

Our experience with the use of glaucoma shell tamponade for bleb leaks in six patients is described. All patients had posterior lip sclerectomies, with leaking blebs diagnosed intraoperatively (2 patients), early (2 patients) and late (2 patients) following surgery. The glaucoma shell works by applying a high resistance to excessive aqueous humor run-off through the leaking wound, and promotes conjunctival epithelial closure by approximating the wound edges. In all six cases the use of the glaucoma shell tamponade was fully effective. The leaks were sealed off and diffuse functioning filtering blebs were maintained, with very low intraocular pressure. We recommend the use of the glaucoma shell tamponade as the treatment of choice for bleb leaks prior to considering surgical repair.

Topical fluorouracil. II. Postoperative administration in an animal model of glaucoma filtering surgery.

Unilateral posterior lip sclerectomies were performed in ten owl monkeys. Five milligrams of fluorouracil was injected subconjunctivally in each operated eye immediately after surgery. Three drops (approximately 2.4 mg/drop) of fluorouracil were instilled ten minutes apart in each operated eye twice daily on postoperative days 1 through 7 and once daily on postoperative days 8 through 15, 17, 19, and 21. One monkey died on the seventh postoperative day; its death could not be attributed to systemic fluorouracil toxicity. All of the operated eyes had filtering blebs after the full course of fluorouracil, but seven also had corneal epithelial defects. By the seventh postoperative week, two of the operated eyes manifested moderately severe corneal opacification. Ten weeks postoperatively, the electroretinographic a- and b-wave amplitudes averaged 17% and 12% less, respectively, in the seven operated eyes without clinically significant corneal opacification than in the unoperated fellow eyes. Only two eyes had blebs after the 12th postoperative week. Histopathologic examination was performed on five eyes, of which only two revealed patent sclerostomies. Although topical fluorouracil appears to delay bleb scarring, the corneal findings suggest that it may be more toxic than subconjunctival fluorouracil.

5-Fluorouracil and Glaucoma Filtering Surgery: I. An Animal Model

Failure of a glaucoma filtering procedure commonly results from scarring at the surgical site. Fibroblasts play an important role in the scarring process. 5-fluorouracil is an antimetabolite capable of inhibiting fibroblast proliferation. We tested the ability of 5-fluorouracil to inhibit cicatrization at the filtering site in an experimental model. Posterior lip sclerectomies were performed in each eye of ten normal owl monkeys. Postoperatively, one eye of each animal received subconjunctival injections of fluorouracil and the fellow eye received saline injections in a randomized, masked fashion. Two animals died of undetermined causes. None of the control eyes developed blebs, but six of the eight treated eyes in surviving animals developed blebs. The difference between intraocular pressures in fluorouracil-treated and control eyes was statistically significant (P < 0.05). Signs of ocular toxicity included persistent corneal epithelial defects and delayed healing of the conjunctival incision. These results are considerably more favorable than those previously reported with experimental filtering procedures in non-human primates. Pharmacologic modulation of wound healing may decrease the risk of failure of filtering operations.

Filtration Surgery in the Treatment of Neovascular Glaucoma

The disappointing visual acuity results following cyclocryotherapy for neovascular glaucoma have prompted us to consider filtration surgery as a reasonable alternative in the treatment of selected patients. All cases of surgically treated neovascular glaucoma were reviewed. There were 26 operations in 24 eyes with a follow-up ranging from six months to seven years and a mean of 22.8 months. Adequate pressure control was obtained in 16 of the 24 eyes (67%). In the eyes with successful control of intraocular pressure, vision was 20/400 or better in eight of the 16 eyes (50%). Four patients (17%) lost light perception. Approximately one half of the operations were trabeculectomies, and the others were posterior lip sclerectomies. There seemed to be no significant difference in the final intraocular pressure levels, number or degree of complications, or successes within the two subgroups. Panretinal photocoagulation, topical steroids, cycloplegics, and time for these measures to have their effect are important preoperative adjuncts to surgical treatment. We are encouraged by the long-term preservation of vision and control of intraocular pressure in many of these eyes.

Late Endophthalmitis after Filtering Surgery

The variety of types of underlying glau­ coma present in our series of 11 cases is shown in Table 1. Seven had had thermal sclerectomies performed by alternately in­ cising sharply and cauterizing the limbal wound until a fistula is made into the ante­ rior chamber. Three patients had posterior lip sclerectomies performed with a Holth punch. Two or three bites of sclera were taken from the posterior lip in the manner described by Haas and Iliff. A single pillar iridencleisis operation was performed on one patient. Tenon's capsule resections were not performed in any case. Ten of the 11 filter­ ing blebs were described postoperatively as thin-walled and cystic, and their size ranged from one and one-half to three clock hours. Postoperative tensions ranged from 5 to 22 mm Hg with two eyes in chronic hypotony (Cases 7 and 8) . The time elapsing between surgery and the onset of infection was from four months to 11 years. The average was 45 months.

FLAP PERFORATION IN GLAUCOMA SURGERY SEALED BY A TISSUE PATCH.

The perforation of the flap consisting of conjunctiva and Tenon's capsule is a serious complication in a glaucoma filtering operation. It results in a collapsed anterior chamber and hypotony. Closing the perforation is most difficult1-6especially if it occurs at the limbus over the sclerectomy. At this point, the conjunctiva is so thin and friable that it is virtually impossible to achieve a watertight closure by suturing to the more rigid cornea. A second layer of conjunctiva, however, used as a tissue patch, will seal the hole effectively without the necessity for sutures in the immediate operative area. In the posterior lip sclerectomy,7the initial incision is 8 mm behind the limbus (Fig 1,AandB). The conjunctiva and Tenon's capsule are undermined as far as the Tenon's scleral reflection (Fig 2,AandB). It is at this point, the anterior limit of the undermined area,

ANTERIOR-POSTERIOR LIP SCLERECTOMY FOR OPEN ANGLE GLAUCOMA.

For several years anterior-posterior lip sclerectomy with peripheral iridectomy has been our operation of choice for patients with uncontrolled chronic open angle glaucoma. The basic features of this procedure as we perform it are; (1) a long, widely dissected conjunctival flap, (2) opposing anterior and posterior lip sclerectomies done with a Holth punch, (3) a small peripheral iridectomy, (4) the injection of air beneath the conjunctival flap as it is closed, and (5) massage of air from the filtering bleb into the anterior chamber at the conclusion of operation. Akinesia and anesthesia are established with a modified Van Lint lid block and a retrobulbar injection of 2 cc of 2% lidocaine with adrenalin containing 7.5 turbidity reducing (TR) units of hyaluronidase per cubic centimeter. The surgical technique is shown in the following series of drawings made from a motion picture of this procedure. Attention to technical detail contributes to the

Posterior Lip Sclerectomy

Posterior Lip Sclerectomy