Filtration implant

Miniature filtration device more effective as a solo procedure

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The XEN Gel (AqueSys) appears to provide better intraocular pressure (IOP) control when it is implanted as a solo procedure than it does when combined with cataract surgery, according to a study presented at the XXXV Congress of the ESCRS by Jan Van der Hoek MD, FRCOphth. “Our early ‘real world’ clinical outcomes show good reductions in IOP and use of medication, albeit with lower success rates than shown in published data. Although XEN placement is a convenient operation to combine with cataract surgery, our data suggest that combining phaco with XEN is slightly less effective for IOP lowering than XEN alone,” said Dr Van der Hoek, Scarborough General Hospital, Scarborough, UK. He noted that the XEN Gel implant is a subconjunctival filtration device. However, unlike trabeculectomy and other filtration surgeries it requires no dissection of the sclera or conjunctiva. It is composed of a soft pliable collagen-derived gelatine material. It is inserted using a 27-gauge needle and visualising the meshwork with a gonio mirror. The retrospective study included outcome data from 58 XEN gel insertions collected from April 2016 to March 2017 at day one and at months one, three, six and 12 using a specially adapted computer database. The patients’ mean age was 74.3 years (range 43-92), 38 patients underwent both phacoemulsification and XEN implantation and 18 underwent solo-XEN. All had mild-to-moderate open-angle glaucoma with a mean preoperative IOP of 24.6mmHg. At six months’ follow-up, the overall mean IOP was reduced to 14.7mmHg. Mean IOP was reduced from 23.6mmHg to 16.9mmHg in the phaco-XEN group and from 25.2mmHg to 15.3mmHg in the solo-XEN group. IOP REDUCTION The treatment’s overall rate of success, that is an IOP lower than 22.0mmHg and a 20% IOP reduction without topical pressure-lowering treatment, was 55%, and the overall rate of complete or qualified success, defined as IOP reduced to the same levels but with topical medication, was 83%. However, in the phaco-XEN group only 40% achieved complete success and only 65% achieved complete or qualified success, whereas in the solo-XEN group, 62% achieved complete success and 76% achieved complete or qualified success. It should be noted that in the phaco-xen group a high number of patients had IOP of 22 or less preoperatively on medication and many of these maintained their pre-op IOP levels without medication postoperatively. If these are also included in the qualified success group the phaco-Xen group achieved 86% complete or qualified success at six months. He noted that the procedure appeared to be safe, there was no visual loss and there were no flat anterior chambers. Two patients had a prolonged hypotony in two eyes, which resolved at one month. One patient required bleb repair at day one and 17 required revision and needling. Jan van der Hoek: jvdh@doctors.net.uk