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 Table of Contents  
CASE REPORT
Year : 2022  |  Volume : 2  |  Issue : 2  |  Page : 411-412

Is XEN-glaucoma gel microstent safe enough in phakic eyes?


Department of Ophthalmology, Haydarpasa Numune Research and Training Hospital, Istanbul, Turkey

Date of Submission31-Dec-2020
Date of Acceptance06-Oct-2021
Date of Web Publication13-Apr-2022

Correspondence Address:
Oksan Alpogan
Selimiye, Tibbiye Street. Nr: 23, 34622, Uskudar, Istanbul
Turkey
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijo.IJO_3817_20

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  Abstract 


Minimally invasive glaucoma surgery (MIGS) is usually preferred as it causes less complications in glaucoma surgery. XEN Glaucoma Gel Microstent (XEN-GGM, Allergan Plc., Parsippany, New Jersey) is one of the MIGS used in glaucoma surgery. Different complications of XEN-GGM that developed during or after the operation have been reported. In our case, anterior capsule perforation occurred and a cataract consequently developed during the XEN-GGM application. For this reason, the measures that must be taken during XEN-GGM application in phakic patients are discussed.

Keywords: Anterior capsule perforation, complication, glaucoma, minimally invasive surgery, XEN


How to cite this article:
Alpogan O. Is XEN-glaucoma gel microstent safe enough in phakic eyes?. Indian J Ophthalmol Case Rep 2022;2:411-2

How to cite this URL:
Alpogan O. Is XEN-glaucoma gel microstent safe enough in phakic eyes?. Indian J Ophthalmol Case Rep [serial online] 2022 [cited 2022 May 27];2:411-2. Available from: https://www.ijoreports.in/text.asp?2022/2/2/411/342995



Many authors tend to prefer MIGS to refrain from the possible complications of filtering surgery and seton surgeries.[1] XEN-GGM via ab interno approach reduces intraocular pressure (IOP) by creating a continuous outflow from the anterior chamber to the subconjunctival area. The XEN-GGM reduces IOP through a mechanism similar to that of trabeculectomy. It is a hydrophilic tube consisting of swine- or bovine-derived gelatin and cross-linked glutaraldehyde. The biocompatibility of gelatin has been demonstrated in clinical trials. It is recommended that the 6-mm-long XEN-GGM implant be placed 2 mm in the subconjunctival area, 3 mm in the sclera, and 1 mm in the anterior chamber. It has advantages such as minimal injury to the conjunctiva and surrounding tissues, a shorter duration of surgery, and repeatability.[2]

This case report was aimed to focus on a possible complication, namely, anterior capsule perforation, which occurred during a XEN-GGM surgery, and the authors wanted to review its causes.


  Case Report Top


In a 54-year-old woman with open-angle glaucoma followed in our clinic, a MIGS was planned with implantation of XEN-GGM as drug compliance was poor in the patient. Detailed ophthalmological examination was performed before surgery. Ophthalmological examination revealed that her visual acuity was 10/10 (decimal system) with Snellen chart in both eyes with a normal anterior chamber. On gonioscopy, the angle was noted as grade 3 in both eyes whereas pigmentation was grade 2.

In the surgical phase, after topical anesthesia, intraocular 2% lidocaine HCl was applied and 1.8% sodium hyaluronate was administered into the anterior chamber before stent implantation. The procedure was sustained after proving that the implant protruded from the desired conjunctival area. However, a rebound movement of the tip of the injector during the last step of exit caused pain in the patient, resulting in sudden eye movement. As a result, the injector's tip perforated the anterior lens capsule during this sudden eye movement and rapid withdrawal of the injector. Although there was no filtration under the conjunctiva, no additional intervention was performed to fix the stent [Figure 1]. After the surgery, anterior chamber reaction and cataract formation were not observed in the eye during the follow-up examinations of the first 4 weeks. Mild lens opacification started to develop after the first postoperative month. However, this did not affect the visual acuity. In the fourth month, however, the patient's visual acuity decreased gradually, therefore a cataract surgery was planned.
Figure 1: Image of atrophic area observed during trace of subconjunctival XEN injector after cataract surgery performed on month 4 due to anterior capsule perforation

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  Discussion Top


The majority of XEN-GGM studies focused on IOP control, reduction in the number of medications used, bleb needling, and early and delayed complications.[1]

In a case series of 64 patients, the cataract formation rate was reported as 11% during a 4 years' follow-up.[3] Cataract formation due to anterior capsule perforation was not reported during the operation.

The XEN-GGM was approved by FDA for use in phakic patients. In a study, it was emphasized that the learning curve is easier for XEN-GGM when compared to traditional filtering surgery.[4] Marques et al.[5] stated that the learning curve was completed after performing six surgeries in either experienced or inexperienced surgeons. A complication as such occurred in our patient although it was the 12th XEN-GGM surgery of the surgeon.

In our case, rebound movement occurred at the tip of the injector as soon as the stent was detached from the injector. This rebounding movement resulted after contact with the iris and consequent stimulation of pain receptors in the area. Therefore, we want to emphasize that anterior capsule perforation may occur when sudden eye movement and rapid withdrawal of the injector coincide. We contemplate that the rebound movement was due to the uncomfortable position of the operator's hand. To avoid rebound movement during exit, hand position should be checked during stent injection. An irregular corneal curvature may indicate an incorrect hand position and may result in the consequent occurrence of rebound movement in the eye. If rebound movement occurs, pulling back slowly can prevent such a complication. Additionally, re-designing injector ergonomics for surgeons with small hands can be helpful.


  Conclusion Top


In conclusion, in phakic patients, anterior capsule perforation may be one of the potential complications, and surgeons should be cautious in patients under topical anesthesia throughout the whole surgical procedure. We believe that general anesthesia or retrobulbar block, or peribulbar anesthesia should be preferred when patients are young, non-compliant, or very anxious.

Declaration of patient consent

Informed consent was obtained from the patient for the images.

Acknowledgments

The authors thank Prof. Dr. Sarper Karakucuk for language editing of the manuscript.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Karimi A, Lindfield D, Turnbull A, Dimitriou C, Bhatia B, Radwan M, et al. A multi-centre interventional case series of 259 ab-interno Xen gel implants for glaucoma, with and without combined cataract surgery. Eye (Lond) 2019;33:469-77.  Back to cited text no. 1
    
2.
Lewis RA. Ab interno approach to the subconjunctival space using a collagen glaucoma stent. J Cataract Refract Surg 2014;40:1301-6.  Back to cited text no. 2
    
3.
Lenzhofer M, Kersten-Gomez I, Sheybani A, Gulamhusein H, Strohmaier C, Hohensinn M, et al. Four-year results of a minimally invasive transscleral glaucoma gel stent implantation in a prospective multi-centre study. Clin Exp Ophthalmol 2019;47:581-7.  Back to cited text no. 3
    
4.
Szigiato AA, Sandhu S, Ratnarajan G, Dorey MW, Ahmed IIK. Surgeon perspectives on learning ab-interno gelatin microstent implantation. Can J Ophthalmol 2018;53:246-51.  Back to cited text no. 4
    
5.
Marques RE, Ferreira NP, Sousa DC, Pinto J, Barata A, Sens P, et al. Glaucoma gel implant learning curve in a teaching tertiary hospital. J Glaucoma 2019;28:56-60.  Back to cited text no. 5
    


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