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Bleb needling an option before repeat trabeculectomy is attempted
Careful management of the patient intra- and postoperatively may reduce bleb failure, according to one surgeon.
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Thickened or flat blebs respond poorly to needling. Images: Ruderman JM |
Needling a previously viable bleb conserves the conjunctiva and allows faster recovery and fewer complications than repeat trabeculectomy, often with similar results, according to Jon M. Ruderman, MD.
Dr. Ruderman discussed strategies for rescuing a failing bleb in a presentation at the American Academy of Ophthalmology meeting in New Orleans. In-office bleb needling is a shorter, less complicated procedure than a repeat trabeculectomy, Dr. Ruderman said.
“If the patient has had prior filtration surgery and the IOP is too high, instead of going to another site to filter the patient, the ophthalmologist should look at the existing bleb and decide whether or not it can be revived,” Dr. Ruderman told Ocular Surgery News.
Bleb needling
“Needling at the slit lamp may be a reasonable step in most situations where prior bleb function was present,” Dr. Ruderman said in his presentation. Studies of bleb needling have reported varying success rates, ranging from 30% to 94%, he said.
“Bleb revision in a minor operating room, utilizing an operating microscope, probably has greater success than bleb needling, but there have not been any randomized studies to compare the two procedures,” he added. The main difference between the two procedures is the surgeon has more control with a bleb revision than with a needling procedure, Dr. Ruderman said.
In his presentation, Dr. Ruderman reviewed data from a study by Broadway and colleagues of 101 bleb needling procedures. Most of the procedures were performed with 5-fluorouracil, and the period from trabeculectomy to needling ranged from 10 days to 11 years.
In that study IOP was reduced from a mean of 26.5 mm Hg to a mean of 18 mm Hg, with a mean follow-up of 20.2 months. Success, defined as an IOP less than 22 mm Hg, was reached by 59.4% of the study population, Dr. Ruderman said. If the criterion for success was a pressure drop greater than 30%, the success rate was 45.5%, he said. For IOP less than 17 mm Hg without the use of medication, the success rate dropped to 34% after 3 years.
Complications reported in the Broadway study included hyphema (3%), hypotony (2%) and recurrent bleb leak (1%). Other studies, however, have reported more serious complications, such as suprachoroidal hemorrhage, malignant glaucoma and endophthalmitis, he said.
Avoiding bleb failure
Early bleb failure generally occurs within the first 2 to 6 postoperative weeks, Dr. Ruderman said. Factors that can contribute to failure include previous conjunctival surgery, inflammation, aphakia, neovascular glaucoma and long-term use of glaucoma drop medications. Signs that the bleb is failing include thickening and vascularity of the bleb, a gradual increase in IOP, loss of microcysts and the eventual flattening of the bleb, he explained.
In patients predisposed to bleb failure, some early management strategies may help prevent failure and may prevent returning for another surgical procedure, he said.
Dr. Ruderman suggested cautious tissue manipulation during the initial filtering surgery and the use of pre- and postoperative steroids to prevent postop inflammation, a possible cause of tissue scarring and bleb failure. He also recommended intraoperative or postoperative treatment with mitomycin C or 5-fluorouracil. Postop cycloplegics and steroids can be used as well.
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Performing a gonioscopy can help to rule out blockage of the sclerectomy, Dr. Ruderman said.
Following surgery, digital pressure can be applied to the patient’s eye at the sclerectomy site, Dr. Ruderman said. Doing so will “help establish the filtration route for the aqueous to leave the anterior chamber so that the pressure will stay down on a permanent basis,” he explained.
Another management option is to correctly time the release of the sutures, Dr. Ruderman advised. “The surgeon should avoid releasing the sutures within the first 5 days because if the surgeon releases the sutures too early, it may cause the pressure to go too low,” he said.
For Your Information:Reference:
- Jon M. Ruderman, MD, can be reached at University Eye Specialists, 676 N. Saint Claire St., Suite 320, Chicago, IL 60611-2984; 312-475-1000; fax: 312-475-1006; e-mail: j-ruderman@northwestern.edu.
- Broadway DC, Bloom PA, et al. Needle revision of failing and failed trabeculectomy blebs with adjunctive 5-fluorouracil. Ophthalmology. 2004;111(4):665-673.
- Kim Norton is an OSN Staff Writer who covers all aspects of ophthalmology.