Year : 1996 | Volume
: 44 | Issue : 2 | Page : 91--94
Results of intraoperative 5-fluorouracil in patients undergoing trabeculectomy - pilot prial
Binita Shelat, B Sridhar Rao, L Vijaya, B Revathi, Dinesh Garg
Medical Research Foundation, 18 College Road, Madras 600 006, India
Medical Research Foundation, 18 College Road, Madras 600 006
To study the effect of 5-Fluorouracil (5-FU) in glaucoma filtration surgery, 13 eyes of 12 patients with glaucoma were subjected to trabeculectomy with intraoperative one minute exposure of 50 mg/ml 5-FU. The average age of patients was 36.42 ± 18.78 years. Two of the patients had developed hypotony in the fellow eye following the use of Mitomycin C with trabeculectomy.
The mean follow-up period was 9.54 ± 5.17 weeks. Two patients developed a shallow anterior chamber with choroidals postoperatively which responded to conservative treatment. One patient developed an encysted bleb one month after surgery. Single one minute intraoperative exposure to 5-FU is a convenient and inexpensive method which appears to have no significant side effects. It may be a useful adjunctive treatment to optimise the results of glaucoma filtration surgery particularly in young and myopic patients. The long term effects, however, are not known.
|How to cite this article:|
Shelat B, Rao B S, Vijaya L, Revathi B, Garg D. Results of intraoperative 5-fluorouracil in patients undergoing trabeculectomy - pilot prial.Indian J Ophthalmol 1996;44:91-94
|How to cite this URL:|
Shelat B, Rao B S, Vijaya L, Revathi B, Garg D. Results of intraoperative 5-fluorouracil in patients undergoing trabeculectomy - pilot prial. Indian J Ophthalmol [serial online] 1996 [cited 2022 Nov 29 ];44:91-94
Available from: https://www.ijo.in/text.asp?1996/44/2/91/24595
The advent of antimetabolites has greatly altered the prognosis of patients undergoing glaucoma filtering surgery. 5-FU was the first antimetabolite to be introduced which was used in the form of multiple postoperative subconjunctival injections. These injections are painful and have complications like corneal epithelial defects. Mitomycin then became popular as it could be used as a single intraoperative application. Mitomycin used with filtering surgery produced blebs that were extremely thinwalled and avascular. This sometimes led to disastrous complications like hypotony maculopathy and bleb infection, leading to endophthalmitis.
In vitro cell culture studies had shown that single 5 minute exposures to 5-FU and mitomycin had prolonged effects on the proliferation of human ocular fibroblasts in cell culture. Intraoperative 5-FU and mitomycin-C used with glaucoma filtration surgery in rabbits showed a significantly prolonged survival of blebs, but that 5-FU (50 mg/ml) had less marked effect and formed thicker blebs than mitomycin (0.2 and 0.4 mg/ml). A preliminary clinical trial was carried out where an intraoperative exposure to 5-FU was followed by postoperative subconjunctival injections. This trial suggested that fewer postoperative injections were required. Therefore we carried out a pilot study in patients undergoing glaucoma filtering surgery to examine the effects of a single intraoperative one minute exposure of sclera and subconjunctival tissues to 5-FU, 50 mg/ml.
MATERIALS AND METHODS
Surgery was performed on 13 eyes of 12 patients, with various types of glaucoma, from January - July 1994 in this pilot study carried at Sankara Nethralaya, Madras. All the surgeries were performed by one of the two authors (BSR / LV) using a standardised technique. A superior rectus bridle suture was taken and a limbus based conjunctival flap was created 8-10 mm posterior to the limbus. The flap was dissected until a good exposure of the limbus was obtained. A small surgical sponge of the size of 4 mm x 4 mm x 1 mm, soaked in 5-FU in a concentration of 50 mg/ml was placed on the sclera and covered with the conjunctiva for a duration of one minute. The area was then thoroughly irrigated with 10 ml balanced salt solution (BSS). A half thickness triangular scleral flap (4 mm circumferentially and 3 mm radially) was dissected. A 3 mm x 1 mm rectangular block of tissue comprising of clear cornea and trabecular meshwork was excised. A peripheral iridectomy was then done. The Anterior Chamber (AC) was reformed with BSS. The scleral flap was closed with one releasable and one or two permanent sutures with 10-0 monofilament nylon. The conjunctiva was closed in a single layer with posterior interlocking sutures with 8-0 polyglactin (Dexon) suture. A subconjunctival injection of 0.5cc of dexamethesone (2mg) was given in the inferior fornix at the completion of surgery. The eye was patched with topical steroids and mydriatics.
Postoperatively all the patients were given topical 0.1% betamethasone eye drops 4 times daily and 1% atropine eye drops twice daily for a period of 6 weeks. The patients were examined on day 1, day 3, day 7, day 14, 6 weeks, and 3 monthly intervals or earlier if clinically indicated. Postoperative examinations included visual acuity, slit lamp biomicroscopy, applanation tonometry and fundus examination. Surgical success was defined as an intra ocular pressure (IOP) ≤ 21 mm Hg with or without the use of antiglaucoma medications. A complete success was defined as an IOP ≤ 21 mm Hg without medication and a qualified success required antiglaucoma medications to achieve this pressure. A qualified failure was defined as an IOP > 21 mm Hg on maximal medications and a complete failure where further glaucoma surgery was done or recommended, there was hypotony with overt maculopathy, or loss of light perception.
Data from 13 eyes of 12 patients who underwent trabeculectomy with intraoperative 5 FU were evaluated. The ocular diagnosis of these patients is shown in [Table:1]. All the patients had primary or secondary open angle glaucoma.
The demographics of the patients and results of surgery are shown in [Table:2].
Two of the patients had developed hypotony following trabeculectomy with mitomycin surgery in the fellow eye. The first patient had an IOP of 2 mm Hg with a deep AC and macular striae 8 months after surgery, whereas the other patient had an IOP of 4 mm Hg, a deep AC and macular striae 6 weeks after surgery.
[Table:3] analyses the surgical results obtained in this study. The overall success was 92.3%.
In this series, one patient had undergone a prior unsuccessful trabeculectomy. None had undergone prior laser procedure.
Complications were seen in five eyes. Two patients developed shallow anterior chamber with hypotony and choroidal detachment; two patients had hypotony without shallow anterior chambers, choroidals or maculopathy. Both the laser patients responded to conservative treatment. In one of them an intraoperative leak was noticed through a suture track of the 10-0, nylon needle while suturing the scleral flap. This patient was given a Simmon's shell for 2 days which was ineffective as the shell did not remain in place. Later the patient was given a symblepheron ring for 3 days, which helped in the prevention of excessive drainage with reformation of AC and subsidence of choroidal detachment. The other patient was given oral cortico steroids (40 mg per day) and he improved within 3 days. No complications related to hypotony like maculopathy and optic disc oedema were seen. The patients who developed hypotony without shallow anterior chambers or maculopathy were not advised any treatment.
One patient with pseudoexfoliation glaucoma developed an encysted bleb one month after surgery. He had an intraocular pressure of 34 mm Hg, was given medical therapy and advised needling of the bleb with postoperative subconjunctival injections of 5-FU; he, however, deferred the decision of any further surgical intervention.
All other operated eyes developed diffuse, avascular blebs.
The success rate of 92.3% obtained in our study was similar to the success rate reported by Lanigan. This was a pilot study which suggested that one minute intraoperative exposure to 5-FU would be as effective as postoperative subconjunctival injections in inhibiting the proliferation of subconjunctival fibroblasts in the very short follow up. The intraoperative use of 5-FU has several advantages over the postoperative use. The postoperative injections are inconvenient, painful and require repeated hospital visits.
None of the patients had a corneal complication or a conjunctival wound leak. This was similar to that seen by Lanigan. But this was markedly different from the 64% incidence of corneal complications and 35% incidence of wound leaks as reported by the Fluorouracil Filtering Surgery Study using postoperative injections. This may be because the intraoperative drug was washed out from the eye unlike the postoperative injections where the drug remains in the tear film and the corneal epithelium for much longer periods. Also, as the drug remained localised to the treated area, sparing the cut edge of the conjunctiva, the conjunctiva healed normally. In a subconjunctival injection, the drug remains distributed through out the conjunctiva which may increase the risk of a wound leak.
None of the patients had a progression of cataract. Lanigan had reported cataract progression in one patient leading to a loss of visual acuity by 2 lines.
Two patients developed transient postoperative shallow anterior chamber with choroidal detachment and hypotony, while two patients had hypotony without any complications.
The study carried out by Lanigan reported hypotony in one patient without overt maculopathy. Hypotony of 5mm Hg or less has been described following postoperative low dose subconjunctival 5- FU and intraoperative mitomycin-c associated with documented maculopathy.
Two patients had hypotony maculopathy with irreversible visual loss in the other eye following trabeculectomy done with mitomycin C. These patients had intraocular pressures of 19 and 9 mm of Hg following trabeculectomy with 5-FU. This might suggest that the pressure lowering effect obtained with 5-FU may be less than that seen with mitomycin-C. This correlates with the results obtained by Khaw et al in an experimental study on rabbits. This may be advantageous in patients like young myopes who are prone to get hypotony with disastrous results. However, in patients with intractable glaucomas where large reductions of intraocular pressure is required, this drug may not prove to be as effective.,
Although no cases of endophthalmitis were seen during the course of our study, the long term incidence of endophthalmitis may be similar to that seen with subconjunctival 5-FU because of the avascular nature of the bleb. The blebs formed with the use of this drug are diffuse and avascular but not as cystic, thin walled and localised as those seen following the use of mitomycin C. This might reduce the incidence of endophthalmitis and bleb leaks.
Three patients had a visual loss by 3 lines following surgery. One of them had epithelial erosions due to topical neomycin toxicity. The visual loss in the other two patients could not be explained.
The results of this preliminary pilot study suggests that intraoperative 5-FU is a useful adjunctive treatment in patients undergoing trabeculectomy especially in primary filtering procedures and young, myopic patients. However, the long term results obtained with this drug need to be adequately evaluated in a prospective randomised study.
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