February 2019

GLAUCOMA

Trabeculectomy holds its ground for providing reliable IOP reductions in glaucoma patients


by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer


Trabeculectomy bleb
Source: Ingeborg Stalmans, MD

The goal of glaucoma treatment is to maintain the patient’s visual function and related quality of life at a sustainable cost. According to Ingeborg Stalmans, MD, Leuven, Belgium, who spoke at the 36th Congress of the European Society of Cataract and Refractive Surgeons about “good old trabeculectomy,” visual function is best preserved by lowering IOP in a “robust, convincing way.”

Trabeculectomy: the superstar

Studies have consistently demonstrated IOPs of around 12 mm Hg following trabeculectomy. “If you look at various studies, trabeculectomy seems to be very effective in IOP lowering,” Dr. Stalmans said. “It is still the most efficacious procedure, and that is why it is still our gold standard, reliably achieving low target pressures. Long-term data on trabeculectomy have resulted in mostly drop-free patients.”
So why look for alternatives if trabeculectomy is achieving its primary goal? According to Dr. Stalmans, the reason is safety, as some of the complications known to follow trabeculectomy are the nightmare of every glaucoma surgeon.
An early study on trabeculectomy showed that roughly one out of four patients developed hyphema, a shallow anterior chamber, or hypotony after trabeculectomy, and one out of five developed cataract or lost at least one line of Snellen.1 Another investigation demonstrated early postoperative complications in 40% of trabeculectomy patients and late postoperative complications in another 40% in a comparison between tube shunts and trabeculectomy. Forty-five percent of the trabeculectomy patients in this study lost at least two lines of Snellen, whether they developed complications or not.2
“I do want to stress, however, that trabeculectomy has evolved over time. Our techniques have greatly improved and trabeculectomy has been refined. If you look at more recent reports about trabeculectomy outcomes, complication rates have gone down,” Dr. Stalmans said.
Good trabeculectomy outcomes with low rates of surgical complications can be achieved, according to the results of another study that measured surgical success, IOP, visual acuity, complications, and interventions in 428 eyes of 395 patients with open angle glaucoma with no previous incisional glaucoma surgery who underwent trabeculectomy. Complication rates were improved compared to previous studies, with approximately two or more lines of Snellen lost in 5%, late-onset hypotony in 7%, and bleb leaks in roughly 14% of the patients. The study recommended intensive, proactive postoperative care to keep complications low.3

Postoperative care

Experienced glaucoma surgeons agree that labor intensive postoperative care goes a long way to ensure better outcomes after trabeculectomy. Seventy-eight percent of trabeculectomy patients need some measure of postoperative manipulation, whether massage, suture removal, needling, or subconjunctival injections, one study showed, with IOP among patients with interventions always higher than in those that required no intervention.4
“A more recent study showed that 63% of individuals still required postop management after trab,”3 Dr. Stalmans said. “Postoperative manipulations are necessary. We all want a surgery that is fast, easy, effective, with no complications, quick recovery, and no postop manipulations. But can we get there?”

Role of MIGS

“Microinvasive glaucoma surgery (MIGS) uses different aqueous flow routes to achieve IOP reduction,” Dr. Stalmans said. “Also, we now know more about the distal outflow channels, that there is resistance there, that they can collapse and cause outflow problems, even when we bypass the trabecular meshwork. Fibrosis is obviously a big enemy for several of these devices and for several MIGS flow routes, which can only be tackled in the subconjunctival space with the use of antimitotics or with needlings.”
MIGS are potentially less effective than trabeculectomy, according to Dr. Stalmans, as studies comparing MIGS devices to trabeculectomy have demonstrated. “Despite its invasiveness and potential for postoperative complications, trabeculectomy is highly effective. It gives us the lowest pressures, followed in efficacy by external MIGS, internal MIGS, and phacoemulsification. Again, our objective is to best preserve visual function,” she said.
A study that investigated newly diagnosed patients undergoing primary medical or surgical treatment showed that the long-term outcomes were not that different in early glaucoma patients. In patients with more advanced visual defects, however, visual function was better in the long run following primary surgery.5
“Cost effectiveness is part of the way we define the goal of glaucoma surgery,” Dr. Stalmans said. “We need cost effectiveness studies comparing MIGS to trabeculectomy. The cost of treatment has financial implications for the individual and society, as do treatment inconvenience and side effects. Factors affecting cost include device cost, surgery time, training for glaucoma specialists, postoperative manipulations, follow-up frequency, reinterventions, and complications,” she explained.
Treatment cost also comprises patient considerations, such as surgery length, the speed of visual recovery, frequency of bleb manipulation, weekly postoperative visits for the first 4 weeks, lifestyle limitation in the early postoperative period, the potential risk of transient or permanent vision loss, and potential loss of bleb dysesthesia, among others.
“This issue is not black and white, and we can’t say that trabeculectomy is the ideal glaucoma surgery for all our patients. One size fits all is inappropriate in glaucoma surgery, and we have to take into account various factors like efficacy and safety, but also patient experience, cost, and postoperative recovery when we decide which patient we want to treat with which surgery,” Dr. Stalmans said. “Trabeculectomy is effective to lower IOP, and the complication rates have come down with modern techniques but are still a reality. Bleb surgery provides low teen pressures but requires bleb management. Comparative data between trabeculectomy and MIGS are largely lacking, and evidence on cost effectiveness is needed. We have to weigh the options to decide what is best.”

References

1. Edmunds B, et al. The national survey of trabeculectomy III. Early and late complications. Eye (Lond). 2002;16:297–303.
2. Gedde SJ, et al. Postoperative complications in the Tube Versus Trabeculectomy (TVT) study during five years of follow-up. Am J Ophthalmol. 2012;153:804–814.
3. Kirwan JF, et al. Trabeculectomy in the 21st century: a multicenter analysis. Ophthalmology. 2013;120:2532–2539.
4. King AJ, et al. Frequency of bleb manipulations after trabeculectomy surgery. Br J Ophthalmol. 2007;91:873–7
5. Musch DC, et al. Visual field progression in the Collaborative Initial Glaucoma Treatment Study the impact of treatment and other baseline factors. Ophthalmology. 2009;116:200– 7.

Editors’ note: Dr. Stalmans has no financial interests related to her comments.

Contact information

Stalmans: ingeborg.stalmans@uzleuven.be

Trabeculectomy holds its ground for providing reliable IOP reductions in glaucoma patients Trabeculectomy holds its ground for providing reliable IOP reductions in glaucoma patients
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