Hydrogel implant for scleral buckling. Long-term observations

Large orbital masses due to longstanding hydrogel retinal explants

AIM

To describe the features of orbital masses occurring as a late complication of hydrogel retinal explants.

PATIENTS AND METHODS

Retrospective review of patients presenting with orbital masses at decades after retinal surgery.

RESULTS

Two patients with huge orbital masses are described, their presenting 25 and 28 years after retinal detachment repair with expansile hydrogel explants. In one case, the preoperative diagnosis was pleomorphic adenoma, and the other-with extreme distortion of the globe-was considered to be lymphoma or chronic inflammation arising around prior retinal explants. At orbitotomy, the masses were found to be grossly expanded hydrogel explants that were removed piecemeal from their fibrous capsules. Histopathology showed very mild inflammation with occasional multinucleate giant cells and patchy capsular calcification, and an eosinophilic amorphous material staining strongly with Alcian-blue. Surgery was uncomplicated and both orbits healed with marked functional improvement.

CONCLUSION

Expansile hydrogel retinal explants were largely used in the 1980s and can present, often decades after the retinal surgery, with impaired orbital functions due to large parabulbar masses. The hydrophilic material appears to expand very slowly over decades, leading to gross distortion of neighbouring structures and a tumour-like mass.

Removal of MIRAgel scleral buckle implants using Yankauer suction catheter with adjusted diameter

Purpose

A variety of removal methods have been reported for cases wherein MIRAgel-associated complications have occurred. Recently, Santorum et al. reported an aspiration method using a metal microcannula. Herein, we report a novel alternative approach using Yankauer suction catheter based on Santorum et al.‘s method.

Observations

This retrospective case involved a 40-year-old Caucasian man with MIRAgel implant-associated swelling-related complications (strabismus and disfiguring mass effect), who underwent suction-assisted implant removal in January 2020 at Kyushu University Hospital. Surgery was conducted under general anesthesia with an incision made in the superior quadrant, and the degraded MIRAgel implant was aspirated using a Yankauer suction catheter instrument with its diameter adjusted to the space. At the one-month follow-up, there were no early postsurgical complications, and the retina remained completely attached.

Conclusions

Yankauer suction catheter is a useful instrument for removal of MIRAgel scleral buckle implants. It is made up of polyvinyl chloride, which is safer and cheaper, and can be cut to adjust the instrument's diameter according to the surgical field.

Histopathology of Hydrolyzed MIRAgel Scleral Buckles

Introduction

The goal of this study was to histopathologically evaluate the appearance of degrading MIRAgel scleral buckles so that they can be reliably distinguished by ophthalmic pathologists from other foreign materials.

Methods

Retrospective chart review and histopathologic study with special stains, including Alcian blue, periodic acid-Schiff, Masson's trichrome, and Perls' Prussian blue for iron, of 4 cases between 2017 and 2019.

Results

Hydrolyzed MIRAgel scleral buckles from 4 patients had a consistent histopathologic appearance. They had a honeycomb structure with the walls of the lattice ranging from distinct to poorly defined. The walls of the lattice were positive for Alcian blue, while the contents of each cell contained periodic acid-Schiff-positive material. Other special stains were not as valuable in highlighting the material.

Discussion

Although the capsules of MIRAgel scleral buckles have been well studied, the material itself has not been. While clinical history and radiographic appearance are often diagnostic of a hydrolyzed MIRAgel scleral buckle, there are instances of preoperative ambiguity where histopathologic confirmation can be useful.

Conclusions

MIRAgel scleral buckles have a distinct histopathologic appearance that can be readily distinguished from that of other foreign materials.

Clinical and radiographic features of hydrolyzed MIRAgel scleral buckles: A comparative analysis

The MIRAgel (hydrogel) scleral buckle, introduced in the 1980s, was a novel material to repair retinal detachments. It was later discontinued due to the frequency of long-term complications related to buckle hydrolysis and expansion. These complications included pain, limited extraocular motility, and more serious complications such as infection or scleral perforation, which ultimately necessitated surgical extraction as late as 20-30 years after placement. Prompt and proper diagnosis and treatment is often delayed as these buckle-associated complications frequently mimic other orbital pathologies such as tumors or infections. The hydrolyzed MIRAgel buckle exhibits distinct radiographic features that are helpful in arriving at the correct diagnosis, particularly in cases of ambiguous clinical presentation or history. Here, we expand on the previously described radiographic features of hydrolyzed MIRAgel and compare them to features of common, mimicking orbital pathology.

Optic Nerve Compression From MIRAgel Implant Migration in a Monocular Patient

The MIRAgel implantation was popularized in the 1980s as an alternative to silicone for scleral buckle retinal detachment repair. However, long-term follow-up has revealed that the implants can expand, creating globe compression and potentially visually devastating intraocular invasion. The authors document a 33-year-old monocular male patient presenting 20 years after MIRAgel implantation with extensive expansion, posterior migration, globe compression, and possible optic nerve compression. Debulking of the MIRAgel stabilized the vision and restored affected extraocular movements. The authors highlight that posterior MIRAgel migration can cause optic nerve compression, and implant debulking may require a multi-disciplinary approach. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:815-818.].

Globe Loss From Intraocular Invasion of MIRAgel Scleral Buckle Components

PURPOSE

To describe intraocular invasion of MIRAgel scleral buckles requiring evisceration.

METHODS

This is an Institutional Review Board-approved retrospective consecutive case series of eyes requiring evisceration secondary to intraocular intrusion of MIRAgel implants performed at the Cole Eye Institute from 2000 to 2014. Charts were reviewed for age at surgery, gender, laterality, time between MIRAgel placement and evisceration, preoperative examination and imaging results, intraoperative findings, postoperative complications, and duration of follow up.

RESULTS

Five eyes of 5 patients underwent evisceration due to a blind, painful eye secondary to MIRAgel expansion. The mean time between MIRAgel placement and evisceration was 21 years (range: 17-30 years). Preoperative ultrasound identified intraocular MIRAgel in 3 of 5 cases; however, intraocular MIRAgel was identified during surgery in all 5 cases. A transocular-approach orbitotomy was performed at the time of evisceration in an effort to remove the MIRAgel. Postoperative complications included ptosis and inability to retain an ocular prosthesis. No cases of orbital implant extrusion occurred.

CONCLUSION

Scleral invasion and intraocular penetration of MIRAgel may occur decades after placement. This may result in a blind, painful eye requiring evisceration and orbitotomy to remove residual material. Suspicion of intraocular penetration of implant should be high in blind, painful eyes. Surgical removal can be difficult due to MIRAgel fragmentation. Conjunctival insufficiency may result in the need for further surgery after evisceration.

Imaging characteristics of the postoperative globe: a pictorial essay

Recognizing imaging characteristics after ophthalmic surgery is necessary for radiologists to prevent misdiagnosis. We review typical appearances of intraorbital implanted devices and materials on CT and MRI with demonstration of the common surgical procedures. EX-PRESS glaucoma filtration devices appear as punctate areas of metal attenuation on CT and are typically placed at the corneoscleral junction. The imaging manifestations after cataract extraction are absence of the native lens of ovoid mass and the intraocular lens with high attenuation on CT and low signal intensity on MRI. The treatment of retinal detachment is achieved with intraocular tamponade or scleral buckling. In intraocular tamponade, the eye is filled with a bubble of gas or silicone oil. Gas results in air attenuation on CT and low signal intensity on MRI in the vitreous cavity. Silicone oil is hyperattenuating on CT and has variable intensity on MRI. In scleral buckling, the eye wall is indented with silicone buckling elements that show high or low attenuation on CT and low T1- and T2-weighted intensity on MRI. Degraded hydrogel buckling elements appear as swollen masses showing low attenuation on CT and high T2-weighted intensity on MRI.

MIRAgel: the immunohistochemical expression of CD3, CD34, and CD68 in the surrounding capsule

PurposeTo study the immunohistochemical features of the capsule tissue surrounding MIRAgel episcleral buckles.Patients and methodsThis Institutional interventional clinical cohort study examined a consecutive series of 21 referred patients who required MIRAgel removal from July 2009 to July 2013. All patients with hydrated and fragmented MIRAgel episcleral buckles were included in this study. Capsule biopsies from MIRAgel episcleral buckles were obtained from all patients. Capsule specimens of seven patients with extruded silicone bands were processed as controls. Paraffin-embedded specimens were examined using light microscopy and immunohistochemistry (via the PAP horseradish peroxidase technique) to detect the expression of CD3, CD20, CD34 and CD68, and S-100 protein.ResultsInflammation with granuloma, which was primarily related to sutures, was found in all (n=36) of the MIRAgel specimens and foreign body granulomas with multinucleated giant cells, histiocytes, and macrophages (CD68+ cells) surrounded the MIRAgel fragments. Average number of CD68+ cells was higher (P<0.001) for MIRAgel than for silicone rubber. The lymphocytic inflammatory infiltrate related to the MIRAgel fragments was CD3+ and CD20- (delayed T cell-mediated immune response). Moderate neoangiogenesis was indicated by the presence of CD34+ cells.ConclusionsThe immunohistochemical analysis revealed that the immune system is able to identify the fragments of MIRAgel (after its hydrolytic degradation) as a foreign body during a delayed T cell-mediated immune response. The phagocytosis by macrophages likely triggers and perpetuates local disease. Removal of MIRAgel explants before hydrolysis should be considered.

Outcomes and complications of hydrogel scleral explant removal

BACKGROUND AND OBJECTIVE

To report symptoms of extrusion of hydrogel explants after retinal detachment (RD) repair and the outcomes and complications following removal.

PATIENTS AND METHODS

All 23 patients had previous RD repair by episcleral buckle with hydrogel explant. Signs and symptoms of scleral buckle (SB) extrusion were analyzed. Main outcomes measured were redetachment of the retina, persistent diplopia, and decreased postoperative visual acuity (VA).

RESULTS

Mean time between RD repair and removal of extruded SB was 16.2 years (range: 11 to 21 years). Fifteen patients (65%) received encircling SB and 8 had segmental SB. SB was combined with vitrectomy in 12 patients and 3 received silicone oil. Common complaints included limited ocular motility, presence of a palpable mass under the eyelid, pain and discomfort, diplopia, visible SB under eroded conjunctiva, complete immobility, and signs of infection. Two eyes were phthisical. No scleral perforations occurred during removal of explants. After SB removal, RD recurred in 2 patients and diplopia persisted in 4. VA was not affected by SB removal.

CONCLUSION

Deterioration may occur after implantation for 10 years or longer. This is due to microstructural change of the hydrogel material. The most common problems are motility disturbance and presence of a tumor-like, palpable mass under the eyelid. Removal of the implant can alleviate some ocular problems. However, RD can recur and diplopia may persist after removal of the SB. Vision usually is not affected.

[Diplopia complicating scleral buckling surgery for retinal detachment]

INTRODUCTION

Diplopia is a well-known complication of scleral buckling for retinal detachment. It is generally caused by ocular motility disturbances.

SUBJECTS AND METHODS

We conducted a retrospective study on patients operated on for retinal detachment between 1998 and 2006 at Strasbourg University Hospital (France) who secondarily complained of diplopia. Patient history, scleral buckling type, and early and late postoperative complications were described.

RESULTS

Among 821 patients who underwent scleral buckling, 12 developed diplopia lasting more than 3 months. Six of the scleral buckling operations were vertical, three horizontal, and three oblique. Examination of the 12 patients showed seven cases of hypertropia, two cases of hypertropia associated with esotropia, one case of hypertropia with exotropia, and two cases of exotropia. The scleral buckle was removed in first intention in all 12 patients; binocular single vision was restored in six cases. Secondarily, prism correction restored binocular vision in three additional patients. Strabismus surgery was necessary for the remaining three patients.

DISCUSSION

Diplopia following retinal detachment usually responds to simple measures. In our study, the removal of the buckle restored binocular vision in the majority of cases, a prism correction was useful for the remaining patients. Strabismus surgery was often very efficient.

CONCLUSION

Diplopia complicating scleral buckling generally responds to simple treatments that can eliminate a handicapping functional deficit.

Scleral MIRAgel causing bony orbital erosion

The authors report a case of hydrogel scleral explant (MIRAgel) causing an incomitant strabismus, diplopia, enophthalmos and a dehiscence in the roof of the orbit secondary to pressure-related atrophy due to swelling of the explant occurring 10 years after its placement.

Expanding MIRAgel Scleral Buckle Simulating an Orbital Tumor in Four Cases

PURPOSE

To describe four patients with an enlarging orbital mass from a swollen MIRAgel scleral buckle that simulated an orbital neoplasm.

METHODS

In a retrospective, single-center case series at the Ocular Oncology Service at Wills Eye Hospital of Thomas Jefferson University, 4 eyes of 4 patients were referred for evaluation and treatment of a suspected orbital tumor.

RESULTS

The initial presenting features were orbital mass (case 1), strabismus (case 2), and conjunctival mass with orbital extension (cases 3 and 4). Each patient vaguely recalled previous uncomplicated retinal detachment surgery 12 to 20 years earlier. Confirmation of the buckling implant material was made with the retina surgeon in 3 cases. A nontender, forniceal conjunctival mass, deep to the Tenon fascia and appearing as a translucent firm elevation was seen in all 4 cases. Axial CT (case 1) revealed a circumscribed anterior temporal orbital mass, believed to be a large inclusion cyst, 4 times thicker than the nasal scleral buckle. Ocular ultrasonography depicted an echolucent mass in the episcleral region (cases 3 and 4) that was 2 times thicker than the nasal scleral buckle (case 3). Excision was attempted in case 1, but only piecemeal removal was achieved, leading to extensive postoperative inflammation and decreased vision. The other 3 cases were followed conservatively without excision because they were each recognized to be a swollen MIRAgel implant and not an orbital tumor.

CONCLUSIONS

MIRAgel scleral buckle material can greatly enlarge over a period of 10 years and simulate an orbital tumor or orbital cyst. Patients often do not recall details of the retinal surgery. Caution is advised regarding excision of this material because it is friable and can lead to extensive postoperative inflammation.

Complications of hydrogel explants used in scleral buckling surgery

PURPOSE

To report a group of patients with symptoms of pain, strabismus, sensation of orbital fullness, and presence of a subconjunctival mass many years after successful scleral buckling surgery using hydrogel explants.

DESIGN

We present an interventional consecutive case series of patients who underwent scleral buckling surgery using hydrogel explants from 4 to 14 years before onset of clinical symptoms.

SETTING

This is a retrospective, multicenter clinical study.

PATIENT POPULATION

17 eyes of 15 patients presented with this disorder. All patients were examined; Snellen acuity, ocular motility, tonometry, slit lamp, and fundus examination were recorded. Two patients underwent either computed tomography or magnetic resonance imaging. Removal of the hydrogel explant was attempted in all patients. Removal of the buckle was technically difficult; the hydrogel material was fragile and fragmented when handled.

RESULTS

All patients had prompt relief of pain and discomfort. Ocular motility and diplopia were greatly improved. Extraocular muscle surgery was not required in any case. Three eyes had intraoperative eye wall perforation. One eye developed postoperative bacterial endophthalmitis. Five eyes had recurrence of retinal detachment. One eye had additional complications of corneal edema and glaucoma.

CONCLUSIONS

Patients who develop this clinical condition should be considered for removal of the hydrogel scleral buckle. Early recognition of this condition may prevent serious complications associated with delayed removal.

LATE SWELLING AND REMOVAL OF MIRAGEL BUCKLES

BACKGROUND

To describe the indications for removal of Miragel episcleral buckles and to compare them with removed silicone sponges and solid silicone indentations.

METHODS

Retrospective analysis of the charts of patients successfully treated for retinal detachment in whom the episcleral buckle was removed after surgery, with a minimal follow-up of 6 months.

RESULTS

In a series of 90 eyes of 90 patients, including 38 cases of Miragel elements, 25 cases of solid silicone, and 27 cases of silicone sponge removal, the duration of indentation before removal was significantly longer with Miragel (91.9 months) than with solid silicone (10.6 months) and silicone sponges (18.6 months). In eyes treated with Miragel elements, swelling of the material with progressive limitation of ocular motility and protrusion of the buckle beneath the eyelids indicated its removal in 34 (89.5%) eyes. Infection of the buckle and erosion of the conjunctiva with an exposed indentation were significantly more common with silicone buckles. Overall, scleral perforation occurred in four (4.4%) eyes, and retinal redetachment occurred in eight (8.8%) eyes.

CONCLUSION

Late swelling of Miragel buckling elements represents a common indication for buckle removal, significantly different from silicone indentations.

S/e-PTFE episcleral buckling implants: an experimental and histopathologic study

To investigate tissue changes induced by the implantation of a silicone band coated with expanded polytetrafluoroethylene (S/e-PTFE) used as scleral buckling, an experimental and histopathological study was performed in rabbits. The right eyes of eight rabbits were implanted for 28-85 days with S/e-PTFE. No complications were encountered in any of the eyes, so histopathological examinations could be performed. Encapsulations combined with numerous giant cells were found to be surrounding the implants in seven eyes, and deposits from the mineral salts of calcium were found in three eyes, forming granulomas possibly caused by irregularities of the implant surface. The porous structure allowed a peripheral colonization by fibrovascular tissue. Taking into account the histological results, the use of this material does not appear suitable. However, this inflammation was limited and did not merge on surrounding tissues.

e-PTFE as scleral buckling episcleral implants: an experimental and histopathologic study

To investigate the effects of focal implantation of expanded polytetrafluoroethylene (e-PTFE) episcleral implants (i.e., explants or exoplants) on surrounding ocular tissues, an experimental and histopathological study was performed. Twenty-seven Fauve de Bourgogne rabbits eyes were implanted for a period of 3-11 months with oval-shaped e-PTFE episcleral implants. A newly formed capsule constantly encased the implants. Affected by the only two severe complications observed, 2 eyes had an endocapsular acute inflammation and could not be included in the study. Finally, 25 eyes were studied histopathologically. Neither intrusion nor extrusion of episcleral implants was observed. Other changes were related to implant characteristics. The inner surface of the capsule was often covered with numerous giant cells attesting to a foreign-body granuloma developed against the irregular outline of the episcleral implants. The porosity of the material was closely related to its surface irregularity, and also allowed its colonization by a fibrovascular and inflammatory tissue mainly in its peripheral layers. Under episcleral implants, sclera was both thinned and invaginated. Expanded PTFE hydrophobia was the other factor that might have suscitated granuloma. These microscopic changes are in contrast with an overall good apparent experimental tolerance to the material. However, additional studies on the long term behavior of this material would be helpful.

Scleral implants: an historical perspective

Scleral implants are made of absorbable or nonabsorbable materials. One category of absorbable materials consists of donor tissue, either autogenous (fascia lata, plantaris gracilis tendon) or from cadavers (dura mater, sclera, fascia lata). A second category includes gelatin, reconstituted collagen, absorbable gut, fibrin, blood plasma, air, and sodium hyaluronate; of these, specially prepared gelatin seems to be the most useful. Nonabsorbable implant materials have proven more practical than absorbable implants. Solid silicone rubber is currently the most popular scleral implant material. It is soft, easy to handle, and well tolerated. Expandable implants, either temporary or permanent, are used in the form of a silicone balloon filled with liquid. Silicone sponge, also widely used, has the advantage of great softness. However, hydrogels seem to be the ideal scleral implants. The only one commercially available is Refojo's MAI implant. It is very soft and is not damaged by sutures, has a smooth surface, is molded in several sizes and shapes, and has small pores that microorganisms cannot penetrate. When saturated with a water-soluble antibiotic before implantation, this implant releases the antibiotic postoperatively for a longer time than any other implant material. Finally, surgical adhesives are useful when the sclera is too thin or weak to tolerate sutures. The best adhesive available seems to be isobutyl cyanoacrylate.

Perfluorocarbon gases in the suprachoroidal space of rabbit eyes

Four perfluorocarbon gases were injected into the suprachoroidal space of rabbit eyes. Temporary, expanding choroidal detachments were observed in all cases. Depending on the amount of gas injected (0.1 or 0.2 cc, respectively), they lasted 1 or 2 days in the case of perfluoromethane, 4 or 5 days with perfluoroethane, 6 or 8 days with perfluoropropane, and 9 or 11 days with perfluoro-N-butane. Due to its longevity, perfluoro-N-butane appeared to be the most suitable gas for temporary "buckling" of the suprachoroidal space in rabbit eyes.

Experimental suprachoroidal plombage with a urethane based hydrophilic polymer

Small portions of dehydrated hydrophilic polymer (HPU 90, Smith and Nephew) have been inserted into the suprachoroidal space in rabbits to investigate the possible use of suprachoroidal plombage in retinal detachment surgery. As it hydrates, the material causes a pronounced elevation of choroid and retina, and the implants have been well tolerated for periods of up to one year in experimental animals. The implant slowly breaks down and stimulates a simple macrophagic reaction: fibrosis in the overlying choroid is associated with ischaemic gliosis and chorioretinal fusion.