Efficacy and Safety of Ab Externo Open Conjunctiva XEN® 63 µm Implantation with a 30G Needle Scleral Tract in Primary Open-Angle Glaucoma

Abstract

Background: This study aimed to assess the efficacy and safety of the 30G needle mediated ab externo open conjunctiva approach for the XEN 63 µm implant in primary open-angle glaucoma. Methods: A retrospective and non-randomized study was conducted on consecutive cases of medically refractory primary open-angle glaucoma treated with standalone ab externo open conjunctiva XEN^® 63 µm (North Chicago, Illinois) with one-year follow-up. Results: Twenty-two eyes were included. The mean preoperative intraocular pressure was 21.9 ± 7.2 mmHg, and the mean number of glaucoma medications was 2.4 ± 0.9. All patients underwent mitomycin 0.02% application for 2 min, and Healaflow^® (MedicalMix, Spain), was implanted in 11 cases (50%). Complete surgical success was achieved in 14 cases (63.6%). No statistical differences in complete surgical success were noted based on the use of Healaflow^®. A significant reduction in intraocular pressure (11.8 ± 3.4 mmHg) and in the number of hypotensive medications (0.2 ± 0.5 mmHg) was observed 1 year after the procedure. Transient hypotony was detected in 31.8% of cases. Complications secondary to hypotony included four cases of serous choroidal detachment and one case of localized hemorrhagic choroidal detachment, the latter associated with hypotonic keratopathy and hypotonic maculopathy. All these complications evolved favorably with conservative management and adjusted topical treatment. Conclusions: This study highlights the efficacy and safety of this approach for the XEN 63 µm implant in medically refractory primary open-angle glaucoma.

Keywords: XEN63 µm; intraocular surgery; minimally invasive glaucoma surgery; open conjunctiva approach; primary open-angle glaucoma; survival analysis.

Figure 1

Surgical technique for 30-G needle-mediated ab externo XEN^® 63 µm implant. (A) Instillation of sub-Tenon’s anesthetic (2% lidocaine with epinephrine) after initial opening with Vanna’s scissors. (B) Superior fornix-based conjunctival flap with dissection of conjunctiva and Tenon’s capsule. (C) Application of diathermy on the scleral bed. (D) Marking at 2.0 mm from the surgical limbus. (E) Scleral tract performed with a 30G needle. (F) Manual insertion of the XEN® 63 implant using non-toothed forceps. (G) Verification of correct device implantation in the anterior chamber via gonioscopy lens. (H) Checking sub-Tenon’s XEN colocation and placement of sub-Tenon’s Healaflow^®. (I) Layered closure of conjunctiva and Tenon’s capsule with Vicryl 7.0 and 10.0 Nylon sutures.

Figure 2

Cumulative probabilities of complete surgical success after XEN63 µm ab externo (A) and depending on the use of Healaflow (B).

Figure 3

IOP measurements after ab externo open conjunctiva XEN implant. Bar diagram and table describing baseline and postoperative IOP values. Error bars indicated standard deviation of IOP.

Figure 4

(A) Anterior segment photography of AEO XEN in LE, 6 months after surgery. (B) Implantation of the device through the scleral spur in the anterior chamber in LE through visualization with gonioscopy. (C) Filtration bleb with a hyporeflective area and subconjunctival cysts, depicted by AS-OCT. (D) Hypotonic maculopathy and cystoid diabetic macular edema, 1 week after XEN implantation, in a patient with moderate diabetic retinopathy.

Figure 5

Hypotony-associated complications in three different eyes with AEO XEN^® 63 µm. (A) Localized hemorrhagic choroidal detachment 4 weeks after ab externo XEN63 µm implantation in a patient with moderate diabetic retinopathy. (B) Hypotony-associated multifocal choroidal serous detachment 3 weeks after ab externo XEN63 µm. (C) Resolving serous choroidal detachment with nasal choroidal folds after conservative management.