Real-world study data indicate that when compared with traditional trabeculectomy, PreserFlo MicroShunt implantation leads to better visual outcomes and fewer complications. Data also suggest potentially fewer treatment failures with the MicroShunt.
Study design
This retrospective, UK-based multicenter cohort study compared outcomes from 70 eyes (66 patients) that received a PreserFlo MicroShunt and 64 eyes (63 patients) that underwent trabeculectomy. The primary outcome measure was the cumulative rate of surgical failure (defined as IOP >21 mm Hg or <20% reduction from baseline, IOP ≤5 mm Hg, reoperation, or loss of light perception), qualified success (with medication), or complete success (without medication) at 18 months. A cost analysis was also performed, using a National Health Service cost perspective and including treatment, disease management, and adverse effect management costs (a separate evaluation looked at operative and postoperative costs).
Outcomes
Demographics were similar between the cohorts, except that significantly more non-White patients received trabeculectomy and significantly more patients with prior conjunctival-involving glaucoma surgery received the MicroShunt. At the last follow-up date, treatment failure had occurred in 25% of the MicroShunt group and 35% of the trabeculectomy group, a nonsignificant difference. There was a significant difference in change of mean deviation on Humphrey Visual Field: −1.1 for trabeculectomy patients vs +0.6 for MicroShunt patients. Significantly more early and late complications were seen following trabeculectomies. Finally, largely due to fewer follow-up visits and postoperative procedures needed, a cost savings of £245 per eye was estimated for MicroShunt surgery over the study period. This cost savings increased to £566 per eye when applying a 30% volume-related discount.
Limitations
Few outcomes in this study actually reached statistical significance, perhaps owing to the small patient population. Furthermore, discrepancies in technique may have confounded the results somewhat: the work of multiple surgeons, including trainees, across multiple institutions with slight differences in technique were examined in conglomerate. Additionally, mitomycin C 0.4 mg/mL was used in all eyes receiving the MicroShunt and the eyes of non-White patients undergoing trabeculectomy, while 0.2 mg/mL was used in the eyes of White patients undergoing trabeculectomy.
Clinical significance
The results of the study are promising, suggesting that outcomes with the PreserFlo MicroShunt may match or even exceed those of traditional trabeculectomies. In particular, greater visual field stability d and lower complication rates (both statistically significant) were noteworthy. While the MicroShunt appeared to have a lower failure rate than trabeculectomy, this finding did not achieve statistical significance. A larger, ideally prospective study with more standardization of technique may be able to further elucidate potential differences in outcomes between these 2 procedures.
Financial Disclosures: Dr. Lynn Sun discloses no financial relationships.