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    Interventional procedure overview of trabeculectomy with a biodegradable collagen matrix implant for glaucoma

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    Efficacy summary

    Intraocular pressure

    A meta-analysis of 11 studies including 443 eyes comparing trabeculectomy plus biodegradable collagen implant with trabeculectomy plus MMC showed that the percentage reduction in IOP was statistically significantly lower in the trabeculectomy plus biodegradable collagen implant than trabeculectomy plus MMC group for 12 months. The mean difference (MD) was -3.69 (95% confidence interval [CI] -6.70 to -0.68, p=0.02) at 1 month; -2.69 (95% CI -5.17 to -0.21, p=0.03) at 3 months; ‑3.67 (95% CI -6.09 to -1.25, p=0.003) at 6 months; and ‑3.24, (95% CI -6.08 to -0.41, p=0.03) at 12 months. However, there was no statistically significant difference between the groups at 24 months (MD 1.24 [95% CI -9.43 to 11.90], p=0.82), and 60 months (MD 1.10 [95% CI -10.11 to 12.31], p=0.85) (Song 2019).

    A Cochrane review reported a meta-analysis of 8 studies (n=327 participants [333 eyes]), 7 of which compared trabeculectomy plus biodegradable collagen implant with trabeculectomy plus MMC while 1 compared trabeculectomy plus biodegradable collagen implant with trabeculectomy alone. Pooled analysis reported that the reduction in IOP was not statistically significantly different between the 2 groups at day 1 (5 studies [162 eyes], MD 0.51, 95% CI -1.95 to 2.97, I2=55%, p=0.68), 6 months (7 studies [282 eyes], MD 0.43, 95% CI -0.97 to 1.84, I2=54%, p=0.55), 1 year (5 studies [177 eyes], MD 1.40, 95% CI -0.57 to 3.38, I2=54%, p=0.16) and 2-year follow up (2 studies [55 eyes], MD 0.20, 95% CI -1.29 to 1.69, I2=34%, p=0.79). There was substantial heterogeneity between the studies. The mean change in IOP from baseline to 6 months and 1 year between the trabeculectomy plus biodegradable collagen implant group and the trabeculectomy plus MMC group was also not statistically significantly different (6 months, 2 studies [46 eyes], MD -1.24, 95% CI -6.23 to 3.76, p=0.63; 1 year, 2 studies [44 eyes], MD -0.32 [95% CI -5.88 to 5.24], p=0.91) (Wang 2015).

    In a randomised controlled trial (RCT) of 33 patients (40 eyes) comparing trabeculectomy plus shunt device (20 eyes) with trabeculectomy plus biodegradable collagen implant (20 eyes), the change in IOP from preoperative IOP in both groups (23.7 mm Hg in shunt group and 26 mm Hg in collagen implant group), was statistically significant at 1 week (10.8 versus 9.5 mm Hg), 4 weeks (13 versus 14.4 mm Hg), 8 weeks (13.7 versus 14.9 mm Hg), 12 weeks (14.3 versus 15.2 mm Hg) and 6 months (15.8 versus 14.7 mm Hg, all p<0.05). There was no statistically significant difference in change of IOP from preop IOP between the 2 groups at any time of observation (Bhatkoti 2021).

    Complete success rate

    In the meta-analysis of 11 studies, the rate of complete success (defined as IOP, usually 21 mm Hg without medications) was not statistically significantly different between the 2 groups (collagen implant [138/217] versus MMC [156/226], relative risk [RR] 0.91 [95% CI 0.74 to 1.13], p=0.39) (Song 2019).

    In the RCT of 33 patients (40 eyes) comparing trabeculectomy plus shunt device (20 eyes) with trabeculectomy plus collagen implant (20 eyes), complete success (defined as IOP 21 mm Hg without medications) between the 2 groups was not statistically significantly different 6 months after surgery (70% [14/20] in shunt device group versus 60% [12/20] in collagen implant group, p not significant) (Bhatkoti 2021).

    Qualified success rate

    In the meta-analysis of 11 studies, the rate of qualified success (defined as the target endpoint IOP, with or without medications) was not statistically significantly different between the 2 groups (implant group 201/217 versus MMC group 198/226, RR 1.02 [95% CI 0.97 to 1.07], I2=1, p=0.51) (Song 2019).

    In the RCT of 33 patients (40 eyes) comparing trabeculectomy plus shunt device (20 eyes) with trabeculectomy plus collagen implant (20 eyes), qualified success (defined as IOP 21 mm Hg and use of antiglaucoma medications) between the 2 groups was not statistically significantly different 6 months after surgery (15% [3/20] in shunt group versus 25% [5/20] in collagen implant group, p not significant) (Bhatkoti 2021).

    Reduction in glaucoma medication use

    In the meta-analysis of 11 studies, pooled analysis shows there was no statistically significant difference in the percentage reduction in the number of glaucoma medications between the 2 groups at 6 months (4 studies, MD -6.80, 95% CI -14.75 to 1.16, p=0.09) and 24 months (MD 5.33, 95% CI -1.65 to 12.30, p=0.13). A statistically significant difference was noted between the groups at 12 months (MD -25.16, 95% CI -45.26 to -5.05, p=0.01). The reduction in the number of glaucoma medications between the groups was 2.56 versus 2.88 in the 6th month; 2.63 versus 2.74 in the 12th month, and 2.45 versus 2.40 in the 24th month (Song 2019).

    In the RCT of 33 patients (40 eyes) comparing trabeculectomy plus shunt device (20 eyes) with trabeculectomy plus collagen implant (20 eyes), the difference in the number of patients who required IOP-lowering medications at 4, 8, 12 weeks and 6 months between the 2 groups was not statistically significant (Bhatkoti 2021).

    Best corrected visual acuity

    In the Cochrane review comparing trabeculectomy plus biodegradable collagen implant with trabeculectomy plus MMC, 1 study (including 32 eyes) reported that there was no statistically significant difference in best corrected visual acuity (BCVA) at 6 weeks follow up (MD -0.24 logMAR, 95% CI -0.58 to 0.10) (Wang 2015).

    In an RCT of 33 patients (40 eyes) comparing trabeculectomy plus shunt device (20 eyes) with trabeculectomy plus biodegradable collagen implant (20 eyes), the reduction in visual acuity from the preoperative period at 1 week was statistically significant (p<0.05) in the shunt group. Change in visual acuity at 4, 8, 12 weeks and 6 months in the shunt device group was not statistically significant. In the biodegradable collagen implant group, the reduction in visual acuity from preoperative visual acuity at 1 and 4 weeks were statistically significant. At 8, 12 weeks and 6 months, change in visual acuity was not statistically significant (Bhatkoti 2021).