Outcomes of the Shunt Tube Exposure Prevention Study: A Randomized Clinical Trial

Aqueous shunt exposure repair: outcomes and risk factors for recurrence

OBJECTIVE

To investigate the outcomes of aqueous shunt exposure repair and to identify risk factors for recurrent exposure after surgical repair.

METHODS

This is a retrospective interventional case series of consecutive patients who underwent repair of an exposed aqueous shunt. Demographic and clinical data were extracted from the patients' records and survival analysis was employed to determine the probability of survival of the repair without further exposure. Cox proportional regression analysis was utilised to identify potential risk factors for failure of the repair surgery.

RESULTS

Seventy-six eyes of 76 patients were included in the study. The probability of survival without further exposure was 76.2% (CI 66.9-86.8%), 72.7% (CI 62.8-84.1%) and 54.7% (40.5-73.7%) at 1,2 and 4 years, respectively. No eye in which the tube was repositioned in the anterior chamber or in the sulcus (n = 9; 11.8%) developed a recurrence of the exposure. A shorter interval from the time of tube insertion to the repair surgery (HR 2.87 [CI 1.11-7.39]; p = 0.03; reference longer interval), a history of previous surgical revision (HR 3.06 [1.15-8.12]; p = 0.02; reference no prior revision) and the use of a human pericardial donor patch at the time of revision (HR 3.43 [1.16-10.13]; p = 0.03; reference other than pericardium) was associated with an increased risk of exposure recurrence.

CONCLUSION

Aqueous shunt exposure revision is associated with reasonable mid and long term success. A shorter interval from tube insertion to exposure revision, previous revisions and the use of a human pericardium patch were associated with increased risk of failure.

The current alternative for ocular surface and anophthalmic socket reconstruction, cryopreserved umbilical amniotic membrane (cUAM)

PURPOSE

This report presents the results of using cryopreserved umbilical amniotic membrane (cUAM) as an alternative mucosal graft for ocular surface reconstruction in cases of anophthalmic socket contracture (ASC), cicatricial entropion (CE), and conjunctival-scleral defects.

METHODS

The study included patients who underwent non-commercial implantation of cUAM grafts (prepared by corneal banking methods) for ASC, CE, conjunctival defect, and scleral melting. The main success criteria for this study were the comfortable fitting of the ocular prosthesis in ASC patients, the natural eyelid position in CE patients, and the degree of conjunctivalisation in melting patients.

RESULTS

cUAM transplantation was performed in 2 patients who could not use a prosthetic eye due to conjunctival contracture, 2 patients with CE, and 1 patient with conjunctival defect and 1 patient with conjunctival-scleral melting. The primary outcome was achieved in 83.3% (5/6) of patients. In one patient with CE, partial healing was achieved due to the persistence of CE in the medial upper eyelid.

CONCLUSIONS

cUAM is a viable alternative to mucosal grafting for reconstructing the bulbar and palpebral conjunctival surface, fornix, and orbit, with reduced donor morbidity and shorter surgical time. Its regenerative ability allows for tissue defect healing and improves cosmetic appearance through epithelialization within weeks.

Evaluation of pericardium patch graft thickness in patients with Ahmed glaucoma valve implantation: an anterior segment OCT study

PURPOSE

To evaluate the changes in thickness of tissues, specifically the pericardium patch graft (PPG) covering the silicone tube in Ahmed Glaucoma Valve (AGV) surgery.

STUDY DESIGN

Prospective observational study.

METHODS

This study included cases with refractory glaucoma that underwent AGV implantation with PPG coverage. Conjunctival epithelium, stroma and PPG thickness covering the tube were measured using anterior segment optical coherence tomography (AS-OCT) at 1, 6 and 12 months. Additionally, the same measurements were taken 1500 µm away from the tube as a control for the central measurements.

RESULTS

Twenty-seven eyes of 27 patients were evaluated in the study. Although PPG thickness decreased significantly in both regions, the amount of reduction was more pronounced centrally. Centrally, the reduction rate was 21.2% and 34.8% during the 1-6 months period and 6-12 months period, while peripherally it was 3.5% and 5.1%, respectively. No change was observed in the thickness of the epithelium during the follow-up period. There was a significant thinning of the stroma in the central and peripheral regions during the 1-6 months period (30.5% and 17%, respectively). No cases of exposure were observed during the follow-up period.

CONCLUSION

Although the most evident thinning of the layers covering the tube was observed in the early postoperative period, PPG showed a stable decrease even in the late period. The progressive reduction in the PPG thickness observed also in the peripheral region indicates that factors beyond mechanical forces contribute to this degenerative process. AS-OCT could be a valuable non-invasive tool in clarifying this process.

Short- to intermediate-term surgical outcome of Keiki Mehta valve implantation in refractory glaucoma

BACKGROUND

Keiki Mehta body pressure (BP) valve is a glaucoma drainage device that works on the simple mechanism of body pressure.

PURPOSE

To evaluate the short- to intermediate-term efficacy and safety of Keiki Mehta valve implantation in treating refractory glaucoma.

METHODS

This was a prospective, interventional, institution-based study. Adult patients (age >18 years) having refractory glaucoma who underwent Keiki Mehta valve implantation from May 2019 to December 2019 in a tertiary hospital in eastern India were followed up to 18 months.

RESULTS

Twenty patients (20 eyes) with refractory glaucoma who underwent Keiki Mehta valve implantation were followed up on postoperative day 1 and at 1, 3, 6, 12, and 18 months postoperatively. Visual acuity, intraocular pressure (IOP), antiglaucoma medications, and success rate were measured at every visit. There was significant reduction in mean IOP from the preoperative values at every postoperative follow-up ( P < 0.05). Kaplan-Meier survival analysis demonstrated a probability of 50% complete success and 20% qualified success at 18 months. Hypotony was the most common postoperative complication.

CONCLUSION

Keiki Mehta valve implantation is an effective and safe treatment for refractory glaucoma.

Comparative study of the outcomes of newly developed polypropylene-based modified trabeculectomy and glaucoma shunt surgery in neovascular glaucoma

BACKGROUND

Neovascular glaucoma (NVG) is a secondary glaucoma with a poor visual prognosis. Trabeculectomy with antifibrotic agents, glaucoma drainage devices (GDDs), and cyclo-destructive procedures are recommended in patients who are refractory to medical management. However, due to the poor success rate of conventional trabeculectomy and the higher cost of GDDs, alternative procedures need to be looked at.

PURPOSE

To compare the surgical outcomes and economic aspects of a newly developed polypropylene suture bed-based modified trabeculectomy to Ahmed glaucoma valve (AGV) implantation for NVG.

METHODS

It was a prospective interventional study conducted at a tertiary care center between 2018 and 2020. Consecutive patients with NVG with a minimum follow-up of 18 months were included. Surgical outcomes are mainly based on intraocular pressure (IOP) control and the cost of surgery.

RESULTS

Sixty eyes were included out of which 40 (60.6%) underwent modified trabeculectomy and 20 (33.7%) underwent AGV. At the final follow-up, no significant difference (P < 0.05) was found between the surgical outcomes of both groups. The complete success rate (IOP < 21 mm Hg without antiglaucoma medications) was 60 and 65% while the qualified success rate (IOP < 21 mm Hg with antiglaucoma medications) was 30 and 25% in modified trabeculectomy and AGV groups, respectively, at final follow-up. The cost of surgery was significantly higher in the AGV group (P < 0.0001).

CONCLUSION

Modified trabeculectomy as described might be a better alternative for NVG eyes.

Scleral Grafts in Ophthalmic Surgery. A Review

AIM

To summarize the history and current trends in the use of scleral grafts in ophthalmology.

MATERIALS AND METHODS

We conducted a review of the literature through the MEDLINE and Cochrane Library databases. The search terms were "sclera", "graft", and "surgery". The search resulted in 1596 articles, of which we evaluated 192 as relevant. The relevant articles were sorted chronologically and according to the method of using scleral grafts, which enabled the development of a review article.

RESULTS

The sclera has been routinely used in ophthalmology since the 1950s in many different indications. Some of these indications have become practically obsolete over time (for example, use in the surgical management of retinal detachment), but a large number still find application today (especially use in glaucoma or oculoplastic surgery, or as a patch for a defect in the sclera or cornea).

CONCLUSION

Even though allogeneic sclera is currently used less frequently in ophthalmology compared to other tissue banking products and the range of its indications has partially narrowed, it remains a useful material due to its availability and properties.

Umbilical Cord Graft for Refractory Neurotrophic Keratopathy

PURPOSE

The purpose of this study was to evaluate whether an umbilical cord tissue graft (UCG) could promote reepithelialization in refractory cases of neurotrophic keratopathy, which failed traditional treatment modalities including amniotic membrane grafts.

METHODS

This retrospective case series included 3 eyes of 3 patients who underwent UCG placement for refractory stage 3 neurotrophic keratopathy. Records were reviewed to evaluate the clinical course including previous treatments, time to UCG dissolution, time to corneal epithelialization, and recurrence of epithelial defects.

RESULTS

The time of a nonhealing epithelial defect before UCG placement ranged from 7.7 to 30 weeks (mean 21.0). UCG dissolution time ranged from 1.7 to 8.1 weeks (mean 5.0) compared with the previous failed amniotic membrane dissolution time of 0.3 to 1.6 weeks (mean 0.95). The time to complete epithelialization after UCG placement was 7.7 and 8.1 weeks, respectively, for the first 2 cases, whereas the third case did not fully epithelialize. Only 1 eye did not have recurrence of an epithelial defect. The maximum time of maintained epithelialization without recurrence ranged from 5 to 86 weeks (mean 42.7). Follow-up time was 37 to 108.1 weeks (mean 62.2) after first UCG placement.

CONCLUSIONS

UCG may allow for longer retention time of tissue grafts, provide a mechanical barrier for protection, and aid in regeneration of the ocular surface. UCG may be an option for re-epithelialization in recalcitrant cases of neurotrophic keratopathy, after conventional treatments such as amniotic membrane grafts have failed.

The developments in amniotic membrane transplantation in glaucoma and vitreoretinal procedures

The main reasons why Amniotic Membrane (AM) is transplanted in Ophthalmology are: to provide a substrate for cellular growth and to provide tectonic support or as a biological bandage and barrier that protects the wound to facilitate an environment for wound healing. The application of AM is well-documented in corneal disorders of various aetiologies [1], however, research within the field has highlighted how it can be used in conjunctival disorders and most recently, in glaucoma and vitreoretinal procedures. This review explores the preservation modalities of AM and summarises the current literature regarding AM transplantation in Glaucoma and Vitreoretinal conditions. AM transplantation in conjunction with trabeculectomy was reported to be used in two different surgical techniques. They differ in relation to the position of the implant: below the scleral flap or over the entire exposed sclera. The results of these studies suggest that AM transplant is a safe procedure that helps in the improvement of the intraocular pressure when associated with trabeculectomies. Moreover, it enhances trabeculectomies success rates when used along with mitomycin C [2]. The use of AM is also described for managing leaking blebs. It is mentioned to be a suitable alternative to conjunctival advancement. Regarding AM transplantation in glaucoma shunt or valve surgeries, the current literature is relatively limited. However, AM has been described as a good tectonic support for shunt procedures [3]. Successful results are described in the literature for surgical treatments using AM plug for vitreoretinal procedures. In particular macular hole closure and rhegmatogenous retinal detachment. In conclusion, AM transplant is a very promising and versatile adjutant therapy. However, further studies are also required for a better understanding and refinement of surgical techniques.

Combined umbilical cord patching with amniotic membrane graft for corneal surface reconstruction

Background

Umbilical cord patch (UCP) grafts have been successfully used for glaucoma shunt tube coverage and conjunctival surface reconstruction. In recent years, the technique has emerged as a novel alternative for the reconstruction of corneal perforation and descemetocele. This study aimed to evaluate the effectiveness of combined UCP grafting and human amniotic membrane (HAM) transplantation for the management of corneal perforation or descemetocele.

Methods

This prospective, non-comparative, interventional case series included nine eyes of nine patients with corneal descemetoceles and 28 eyes of 28 patients with corneal perforations, all in a clinically quiescent state. UCP grafting and HAM transplantation were combined to treat all patients. We re-examined the patients daily throughout the first week, weekly for 1 month, and then monthly for the first 6 months using slit-lamp examination and anterior segment optical coherence tomography.

Results

We included 37 eyes with descemetocele or corneal perforation in a clinically quiescent state. The mean (standard deviation) ages of patients with corneal descemetocele and corneal perforation were 56.3 (18.8) years and 54.3 (18.1) years, respectively. The male-to-female ratios in patients with corneal descemetocele and corneal perforation were 56% to 44% and 61% to 39%, respectively. Postoperative corneal thickness increased significantly in eyes with descemetocele compared to preoperative values (P < 0.001). Postoperative best-corrected distance visual acuity improved significantly compared to preoperative values in eyes with descemetocele or corneal perforation (both P < 0.001), with relief of accompanying ocular symptoms. We did not observe any recurrence or complications such as rejection, infection, suture-related problems, or severe inflammation and all had a formed anterior chamber up to the final follow-up visit.

Conclusions

Combined UCP grafting and HAM transplantation could be a promising alternative treatment for corneal perforation or descemetocele in clinically quiescent eyes, providing satisfactory reconstruction and functional outcomes. Further studies with robust designs, larger sample sizes, and longer follow-up are needed to verify the efficacy and safety of this modified surgical technique in enhancing vision and restoring anterior segment anatomical integrity in compromised corneas.

Reconstruction with umbilical amnion following ocular evisceration: A case study

Purpose

To report the use of cryopreserved amniotic membrane from the umbilical cord (UC) in the reconstruction of a dehisced wound with the additional ability to increase orbital volume, expand superior and inferior fornices, and improve cosmesis following evisceration of a blind, painful, atrophic, sunken eye with ptosis.

Observations

Patient developed conjunctival wound dehiscence without implant exposure following evisceration. One month later, reconstruction was performed with UC to cover the defect, increase the orbital volume, and expand orbital fornices to allow placement of a large ocular prosthesis with superior lip for ptosis elevation. Post-operatively, at the 6th week, the socket was healthy and the globe had good movement. At the 7th week, the ocular prosthesis was sized and fitted. At the 8th month, the structural integrity of the socket was maintained with deep fornices, and the patient had excellent cosmetic result with natural appearance and movement of the prosthetic eye.

Conclusions and importance

This case highlights the successful utilization of UC graft to augment soft tissue volume, restore socket structural integrity and increase socket volume, and achieve good cosmesis and ocular motility following evisceration.