What is the comparison between ClearPath (canaloplasty) tube and trabeculectomy?

From the Guidelines

Trabeculectomy is generally considered the first-line surgical option for most patients requiring incisional glaucoma surgery, while ClearPath (canaloplasty) tube is often reserved for cases with higher risk of trabeculectomy failure. When comparing ClearPath tube and trabeculectomy for glaucoma treatment, it's essential to consider the benefits and risks of each procedure. Trabeculectomy creates a new drainage channel for aqueous humor by removing a small portion of the trabecular meshwork and adjacent structures, potentially achieving lower intraocular pressures but carrying risks of hypotony, bleb-related complications, and requiring more intensive postoperative management 1.

Key Considerations

• Trabeculectomy provides an alternative path for the escape of aqueous humor into the subconjunctival space, and it often reduces IOP and the need for medical treatment 1.
• The success rate of trabeculectomy varies, with estimates ranging from 31% to 88% in different populations and with varying definitions of success and failure 1.
• Trabeculectomy is typically preferred for primary open-angle glaucoma patients without previous surgery, while ClearPath is better suited for patients with neovascular glaucoma, failed previous trabeculectomies, inflammatory glaucoma, or extensive conjunctival scarring.
• Postoperative care differs significantly, with trabeculectomy requiring more frequent monitoring and potential interventions like suture lysis, while tube shunts generally need less manipulation.

Procedure Comparison

• Trabeculectomy is effective in lowering IOP, but it has a higher associated long-term failure rate 1.
• The use of antifibrotic agents, such as mitomycin-C (MMC) and 5-fluorouracil, can reduce the risk of surgical failure and improve the success rate of trabeculectomy 1.
• ClearPath tube shunt diverts aqueous humor to an equatorial plate, offering more predictable pressure control with fewer follow-up visits, though it may not achieve pressures as low as successful trabeculectomies.

Patient-Specific Considerations

• The choice between trabeculectomy and ClearPath tube should be individualized based on the patient's specific glaucoma type, target pressure, previous surgical history, and the surgeon's experience with each technique.
• Patients with a history of glaucoma surgery or previous cataract surgery involving a conjunctival incision may have a reduced success rate with trabeculectomy 1.

From the Research

Comparison of ClearPath (Canaloplasty) Tube and Trabeculectomy

• The provided studies do not directly compare ClearPath (canaloplasty) tube and trabeculectomy. However, some studies compare trabeculectomy with other nonpenetrating surgical procedures, including canaloplasty 2.
• Trabeculectomy is a reliable alternative to unsuccessful medical or laser treatment, with a success rate of 89% measured 1 year after surgery 3.
• The most common intraoperative complications of trabeculectomy include hyphaema, flat anterior chamber, vitreous loss, and phacodonesis 4.
• Postoperative complications of trabeculectomy include hyphaema, flat anterior chamber, choroidal effusion, leakage, striate keratitis, posterior synechia, hypotony, and high IOP 4, 3.
• Trabeculectomy seems to be the most effective surgical procedure for reducing intraocular pressure (IOP) in patients with open-angle glaucoma, but it is associated with a higher incidence of complications compared to nonpenetrating surgery (NPS) 2.
• In patients with uveitic glaucoma, trabeculectomy and glaucoma drainage devices (GDDs) demonstrate comparable effectiveness in reducing IOP, but there are significant differences in their safety profiles 5.
• In eyes with chronic inflammatory glaucoma, nonvalved tube-shunt surgery may be more likely to maintain IOP control and avoid reoperation than trabeculectomy with antifibrotic therapy 6.

Key Findings

• Trabeculectomy is associated with a higher incidence of complications, including hypotony, choroidal effusion, cataract, and flat or shallow anterior chamber 2.
• GDDs are associated with higher rates of complications, such as cystoid macular edema, need for revision surgery, and uveitic flare 5.
• Trabeculectomy has a higher risk of cataract progression compared to GDDs 5.
• The cumulative probability of failure after 5 years of follow-up is significantly greater in trabeculectomy eyes compared to GDD eyes in patients with chronic inflammatory glaucoma 6.