Dystrophic calcification of silicone scleral buckling implant materials

Complicated calcified alloplastic implants in the nasal dorsum: A clinical analysis

BACKGROUND

In rhinoplasty, calcification around silicone implants is frequently observed in the tip dorsum (TD) area. Additionally, based on a review of various literature, it is presumed that calcification in silicone implants occurs due to both inflammatory chemical reactions and physical friction against the tissue. The calcification of nasal silicone implants not only results in the functional loss of the implants, but also leads to material deformation. However, there is a lack of research on calcification of nasal silicone implants in the current literature.

AIM

To elucidate various clinical characteristics of calcification around nasal silicone implants, using histological and radiological analysis.

METHODS

This study analyzed data from 16 patients of calcified nasal implants, who underwent revision rhinoplasty for various reasons after undergoing augmentation rhinoplasty with silicone implants. The collected data included information on implant duration, implant types, location of calcification, presence of inflammatory reactions, and computed tomography (CT) scans.

RESULTS

The most common location of calcification, as visually analyzed, was in the TD area, accounting for 56%. Additionally, the analysis of CT scans revealed a trend of increasing Hounsfield Unit values for calcification with the duration of implantation, although this trend was not statistically significant (P = 0.139).

CONCLUSION

Our study shows that reducing the frequency of calcification may be achievable by using softer silicone implants and by minimizing the damage to perioperative tissues.

Endoscopic injection of bulking agent around the ejaculatory ducts at the verumontanum for recurrent paediatric epididymitis

INTRODUCTION

Paediatric recurrent epididymitis is frequently observed in several urogenital conditions, and may result in deterioration of long-term fertility. The management of recurrent epididymitis is still a therapeutic challenge for paediatric urologists, and as yet there is no consensus for treatment.

OBJECTIVE

To present a minimally invasive endoscopic approach for the treatment of recurrent epididymitis (more than three episodes).

PATIENTS AND METHODS

Eleven boys were referred with a history of recurrent epididymitis in a context of urogenital malformations. All children underwent endoscopic transurethral injection. Dextranomer/hyaluronic acid was injected around the ejaculatory ducts at the verumontanum (Summary Fig.). The medical records and outcomes of the patients were retrospectively reviewed.

RESULTS

Of the 11 boys, two (18%) had a history of bladder exstrophy, three (27%) anorectal malformation, two (18%) peno-scrotal hypospadias, two (18%) posterior urethral valves, one (9%) seminal vesicle cyst, and one (9%) urethral stricture. The median age at injection was 3.75 years (range 8 months-14.7 years). Endoscopic injection effectively prevented recurrence in eight patients (73%) with a mean follow-up of 3 years (range 6 months-8.8 years). The mean injected volume was 0.7 ml/session. No perioperative complications were recorded. Vas clipping was performed in three patients after unsuccessful injections.

DISCUSSION

The current discussion for management of recurrent epididymitis is mainly based on vas clipping. Endoscopic injection in the verumontanum could offer several potential advantages over vas clipping; moreover, it is easy to perform for an urologist who usually uses endourological approaches. It is believed that only Kajbafzadeh et al. have reported their experience with endoscopic injection in the verumontanum in seven patients with structural anomalies, and they had a 42% success rate. Similarly, the current study did not observe perioperative or postoperative complications.

CONCLUSION

In this series, endoscopic injection of the verumontanum was considered to be a safe and effective treatment in almost 73% of children with recurrent epididymitis. It did not result in perioperative complications and not contraindicate a subsequent surgical procedure such as vas clipping.

Nummular dystrophic calcification of an Ahmed glaucoma valve in a child

We report the case of an otherwise-healthy 4.5-year-old girl with primary congenital glaucoma who had multiple nummular calcium deposits on the dorsal plate of a previously-implanted Ahmed glaucoma valve. The child had received the implant in the right eye at 6 months of age and developed increased intraocular pressure requiring surgical excision of surrounding fibrous encapsulation. Intraoperative inspection revealed that the dorsal plate surface was covered with multiple white nummular lesions; staining and X-ray microanalysis confirmed the lesions to be calcium deposits. Calcium deposits have been documented for various ophthalmic implants, including silicone scleral buckles and intraocular lenses, but to the best of our knowledge they have not previously been described in association with a glaucoma drainage device.

Scleral buckle removal: indications and outcomes

Primary scleral buckling has been an effective means to reattach the retina for over 50 years. After surgery, complications may arise that require scleral buckle (SB) removal. The most common indications for SB removal are extrusion, infection, and pain. I review the pertinent literature in an effort to develop guidelines for when to remove a SB.

Risk factors for development of choroidal detachment after scleral buckling procedure

PURPOSE

To determine risk factors of choroidal detachment after scleral buckling procedure for treatment of retinal detachment.

DESIGN

Retrospective chart review.

METHODS

The authors performed a retrospective study of 69 consecutive cases of retinal detachment from January 2007 to January 2008 treated by scleral buckling surgery. Two groups of patients were defined according to the absence or apparition of choroidal detachment, and a comparison of several parameters between these 2 groups was performed.

RESULTS

Fifteen patients developed a choroidal detachment. The study found an average higher level of systolic blood pressure during surgery in the group with choroidal detachment than in the absence group (127.3 vs 119.1 mm Hg; P = .008). The authors also observed a statistically significant difference between the 2 groups when comparing the intraoperative peak value of systolic blood pressure (149.3 vs 138.5 mm Hg; P = .019). Finally, in the group that developed choroidal detachment, there were statistically more patients with high myopia (P = .02).

CONCLUSION

This study highlights that the 2 main risk factors for development of choroidal detachment during scleral buckling surgery are high blood pressure during the intervention and the existence of high myopia.

Postoperative opacification of polymethylmethacrylateintraocular lens

Background: Opacification of ophthalmic devices has been previously reported in silicone scleral buckle, Molteno implant, and intraocular lens opacification. However, there is no report on polymethyl methacrylate (PMMA) intraocular lens (IOL) calcification. Objective: Report the clinical feature, histopathologic and spectrophotometer analysis of opacified three-piece PMMA IOL. Method: A 60-year-old diabetic patient reported decreased visual acuity in her right eye, which had undergone phacoemulsification with PMMA IOL implantation. The ophthalmic examination revealed a white homogeneous opacification of posterior surface of the IOL. The explanted IOL was analyzed using scanning electron microscopy, energy dispersive spectroscopy, and alizarin red staining. Results: The scanning electron microscope analysis showed granular deposits on posterior surface of the IOL. Using energy dispersive spectroscopy analysis, calcium and phosphate peaks were revealed, which was confirmed by positive for alizarin red staining. Conclusion: This case report provided evidence of PMMA IOL calcification caused by calcium and phosphate deposits. The possible etiologies were extrinsic and/or intrinsic factors.

Scleral patch graft calcification and erosion following Molteno implant surgery

A case of dystrophic calcification of a scleral patch graft and conjunctival tissue erosion 17 years following the implantation ofa Molteno drainage device is described.

Gross and pathologic analysis of long-term silicone implants inserted into the human body for augmentation rhinoplasty: 221 revision cases

BACKGROUND

In augmentation rhinoplasty, delayed morphologic changes are often observed with silicone implants, despite them being known as a safe implant material. The purpose of this study was to identify the cause and time course of delayed shape changes of silicone implants, through the long-term evaluation of inserted implants and their surrounding nasal soft tissues after their removal at revision rhinoplasty operations.

METHODS

Two hundred twenty-one silicone implants removed during revision rhinoplasty were studied. The period of insertion ranged from 1 month to 25 years, with an average of 6 years 7 months. Calcification within the silicone implants and, when available, the capsular soft-tissue attachments were examined with the naked eye and light microscopy.

RESULTS

Calcification was first observed grossly with the naked eye after 5 years 8 months of insertion. With light microscopy, calcification debris could be seen after 4 years. After implant insertion for more than 9 years, focal calcification could be seen in 50 percent of implants. When implants had been inserted for more than 15 years, a denatured type of large calcification was clearly observed. Plasma cell, macrophage, and neutrophil proliferation was noted in the soft-tissue capsule surrounding the superficial calcifications in those individuals with an early inflammatory response, and lymphocyte proliferation was noted in those with a late inflammatory response.

CONCLUSIONS

Silicone implants were noted to induce calcification when inserted for a long time, causing long-term morphologic changes. This should be taken into consideration when choosing silicone implants for augmentation rhinoplasty.

A New Classification of Calcification of Intraocular Lenses

OBJECTIVE

To define and classify the major types of intraocular lens (IOL) calcification.

DESIGN

Retrospective observational case series with clinicopathologic correlation.

PARTICIPANTS

More than 400 IOLs explanted because of opacification.

METHODS

The authors reviewed the clinical information and histologic findings of all IOLs that had been explanted because of opacification or calcification of the IOLs accessioned in their laboratory between January 1999 and December 2004.

MAIN OUTCOME MEASURE

The proposed mechanism that led to calcification of each IOL design.

RESULTS

Three major types of calcification were identified: (1) primary calcification, (2) secondary calcification, and (3) false-positive calcification or pseudocalcification. The primary form refers to calcification that is inherent in the IOL, that is, is based on possible inadequate formulation of the polymer, fabrication of the IOL, or issues with its packaging process. The calcification presumably occurs in otherwise normal eyes and generally is not associated with preexisting diseases. The secondary form refers to deposition of calcium onto the surface of the IOL most likely the result of environmental circumstances (e.g., changes in the aqueous milieu surrounding the implanted IOL associated with preexisting or concurrent diseases or indeed any condition that has disrupted the blood-aqueous barrier). By definition, it is not related to any problem with the IOL itself. The false-positive or pseudocalcification refers to those cases in which other pathology is mistaken for calcification or false-positive staining for calcium occurs.

CONCLUSIONS

When evaluating the pathogenesis and nature of IOL calcification in or on any given design, one should categorize it according to these types. Primary calcification is IOL related and the IOL should be withdrawn or modified to correct the problem. After the cause is identified and the lens is implanted again, patients should be followed up for up to 2 years to be sure the problem is alleviated. Secondary calcification is by definition not IOL related; it may occur with virtually all IOL designs implanted under various adverse circumstances. No IOL, hydrophilic or hydrophobic, is immune to secondary calcification. The false-positive form is recognized readily in the laboratory and this erroneous diagnosis is avoided.

Calcification postopératoire des lentilles intraoculaires acryliques hydrophiles : aspects cliniques et pathologiques

PURPOSE

The aim of this study was to evaluate the clinical aspects of ten eyes with calcified hydrophilic acrylic intraocular lenses and pathological data obtained from seven explanted lenses.

MATERIAL AND METHODS

Forty-seven eyes of 40 patients received the same implant in the first 6-month period of 2001. Ten eyes showed intraocular lens opacification detected 6-18 months after the operation: seven lenses were explanted and three were left in place because they were not causing a decrease in visual acuity or glare at light. Five of ten eyes were diabetic. The explanted lenses were examined under the light microscope and the electron microscope. The elemental analysis of the lens surfaces was made by energy dispersive spectrometry.

RESULTS

The light microscopy showed an irregular surface covered by a gray-white opacity. The electron microscopy detected multiple granulations on the front and back surfaces of the lenses including some portions of the haptics. The size and density of these granulations were smaller on the back surface. The energy dispersive spectrometry showed the presence of calcium and phosphate on both surfaces. The spikes of calcium and phosphate were smaller for the back surface of the lenses.

DISCUSSION

Calcification was predominantly seen on the surfaces that were in contact with aqueous not covered with anterior capsule. Half (5/10) of the cases were diabetic even though 18% of all patients receiving this lens were diabetic. The presence of diabetes is very common in other series. These data suggest the role of a metabolic factor influencing the milieu of the lens in this calcification process.

CONCLUSION

Calcification of the hydrophilic acrylic lenses is a relatively serious complication, but the conditions leading to its appearance and the physiopathology have not yet been fully elucidated. The surgeon should be very careful in the choice of the intraocular lens to implant, and even more so if the patient is diabetic.

Retinal detachment: imaging of surgical treatments and complications

Rhegmatogenous retinal detachment occurs in 5%-7% of the population with a peak prevalence between 40 and 80 years of age. The objects of treatment are to create a chorioretinal scar at the site of the retinal tear and to mechanically appose the detached sensory retina to the underlying retinal pigment epithelium. This apposition is achieved by means of scleral buckling or intraocular tamponade. In scleral buckling, the eye wall is indented under the retinal tear with a silicone buckling element. In intraocular tamponade, the eye is filled with a bubble of air, gas, or silicone oil. In patients treated with these techniques, neuroimaging commonly demonstrates incidental orbital findings. Familiarity with these techniques is essential if the radiologist is to differentiate normal postoperative findings from ocular disease. Furthermore, the ability to recognize the appearance of uncomplicated ocular surgery is a prerequisite for aiding the surgeon in diagnosis of postoperative complications.

Endoscopic treatment with dextranomer-hyaluronic acid for vesicoureteral reflux: histological findings

PURPOSE

Dextranomer-hyaluronic acid co-polymer is the first endoscopic bulking agent approved for vesicoureteral reflux in the United States. We evaluated the histopathological changes associated with this treatment in children with vesicoureteral reflux.

MATERIALS AND METHODS

Children 1 to 11 years old in whom treatment with dextranomer-hyaluronic acid co-polymer for grades III or greater vesicoureteral reflux had failed were eligible for the study. Failure was defined as persistent vesicoureteral reflux on voiding cystourethrography done approximately 3 months after implantation. At ureteral reimplantation the implant and surrounding ureteral tissue were resected and fixed for histopathological analysis. Tissue sections (4 to 5 microm.) were stained for routine histology and examined under a light microscope. Patients with a similar grade of vesicoureteral reflux who had not undergone endoscopic treatment served as the control group.

RESULTS

The study population comprised 23 patients with vesicoureteral reflux, of whom 13 with a mean age of 2 years 8 months at diagnosis underwent 1 to 3 treatments with dextranomer-hyaluronic acid co-polymer. The remaining 10 patients with a mean age of 1 year 10 months at diagnosis did not receive the bulking agent before ureteral reimplantation. The implant remained in situ 13 to 39 months (mean 22). On ureteral reimplantation the implant was located at the site of injection in 12 of the 13 patients. Histologically a granulomatous inflammatory reaction indicated by giant cell infiltration was observed at the implantation site. At ureteral reimplantation 9 implants were pseudo-encapsulated. Calcification was present in 9 ureters, while the eosinophil count was greater than 5 cells per 0.125 mm2 in 7 ureters treated with dextranomer-hyaluronic acid co-polymer. Mast cell infiltration was similar in the treatment and control groups.

CONCLUSIONS

Endoscopic treatment with dextranomer-hyaluronic acid co-polymer for vesicoureteral reflux is associated with a granulomatous reaction of the giant cell type, inflammatory cell infiltration and implant pseudo-encapsulation. They are typical histological findings associated with implantation of a foreign material. Dextranomer-hyaluronic acid co-polymer remains safe and effective for vesicoureteral reflux in children.

Capsular calcification of alloplastic orbital implants

PURPOSE

To report calcification of the capsule surrounding alloplastic orbital implants and postulate this calcification as a possible cause of poor implant motility.

DESIGN

Interventional case reports.

METHODS

Two patients with alloplastic spherical implants after enucleation presented with poor implant motility. Both patients underwent orbital implant exchange with a quasi-integrated porous polyethylene orbital implant.

RESULTS

During removal of the original alloplastic orbital implant, a hard, thick shell adherent to the surrounding orbital tissues was encountered. After complete excision of the shell, microscopic evaluation confirmed a dense, fibrous capsule with calcification. No evidence of inflammation or malignancy was associated with either capsule. Postoperatively, both patients had significant improvement in motility of their new orbital implant.

CONCLUSIONS

Although calcification of the fibrous capsule surrounding alloplastic orbital implants is an unusual finding, it may result in poor implant motility. Capsule excision and implant exchange may significantly improve the motility of the orbital implant.

Assessing intraocular lens calcification in an animal model

PURPOSE

To describe an animal model used to evaluate the propensity of various biomaterials to calcify intraocularly.

SETTING

Research Department, Allergan Inc., Irvine, California, USA.

METHODS

Intraocular lens (IOL) optic materials were implanted intramuscularly and/or subcutaneously in rabbits for up to 90 days. The materials included silicone, poly(methyl methacrylate) (PMMA), hydroxyethyl methacrylate hydrogel, and several hydrophobic acrylic materials. Scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) were used to detect calcification demonstrated by characteristic discrete nodules containing both calcium and phosphate. Histological methods were used to evaluate tissue reactivity. Disc lenses fabricated from the experimental material were also bilaterally implanted in rabbit eyes that were monitored by slitlamp biomicroscopy. The lenses were explanted at 1, 2, 5.5, 10, and 20 months for SEM/EDS analysis.

RESULTS

No calcification was noted in the intramuscularly or subcutaneously implanted silicone, PMMA, and acrylic optic materials. Calcification was noted on the intramuscularly, subcutaneously, and intraocularly implanted experimental acrylic and the intramuscularly implanted hydrogel material; the calcification was more extensive on the hydrogel. Signs that suggested intraocular calcification were first noted on the experimental IOLs at 4 months, but calcification was not confirmed until 10 months.

CONCLUSIONS

Material calcification occurred more quickly in an intramuscular or subcutaneous environment than in an intraocular environment. Intramuscular and subcutaneous implantation appears to be an excellent model for screening materials for calcification potential. However, calcification is both host environment and material dependent. Using intramuscular or subcutaneous implantation in animal models to predict intraocular calcification in humans must be done with caution.

Calcification of poly(2-hydroxyethyl methacrylate) hydrogel sponges implanted in the rabbit cornea: a 3-month study

Poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels have been used in the past as ocular implants. In a recent development, PHEMA sponges have shown suitable properties as materials for the peripheral component of an artificial cornea (keratoprosthesis). However, the propensity of PHEMA to calcify could threaten the long-term stability of the implanted devices. In an attempt to improve the understanding of the calcification mechanism, the dynamics, extent, and nature of calcified deposits within PHEMA sponges implanted in the cornea were investigated in this study, and the possible correlation between necrosis of cells and calcification was critically examined. Samples of a PHEMA sponge were implanted in rabbit corneas and explanted at predetermined time points (2, 4, and 12 weeks). The samples were examined by microscopy (light, transmission, scanning) and energy dispersive analysis of X-rays. Histological assessment and semiquantitative analysis of the amount of calcium deposited was performed using image analysis. An in vitro experiment was also performed by incubating sponge samples for 2 weeks in a solution of calcium and phosphate ions at a ratio similar to that in hydroxyapatite, in the absence of cells. Calcification was not seen in the 2- and 4-week explants, however, small deposits were detected in two of the 12-week explants, both within and on the sponge's constituent polymer particles. The deposit volumes represented 0.094% and 0.21%, respectively, of the total sponge volumes. Calcium deposits were present in large amounts both within the constituent polymer particles and on the surface of the sponges incubated in the abiotic calcifying solution. Cooperative mechanisms are suggested for the calcification of PHEMA sponges in vivo. The initial event may occur at a molecular level, when plasma proteins are adsorbed onto the polymer surface and bound through chelation to the calcium ions present in the medium. After their natural degradation, these structures may act as nucleation sites for calcium phosphate crystallization. Concurrently, the calcium ions can diffuse into the hydrogel particles and then the spontaneous precipitation of calcium phosphate may be caused by supersaturation due to the lower content of water in polymer, an effect which is likely predominant in vitro. The second event is the recruitment of phagocytic cells to clear calcium debris. Degeneration of these cells may then form nucleation sites for secondary calcification.

A study on hydroxyapatite formation on/in the hydroxyl groups-bearing nonionic hydrogels

Using the biomimetic method, we formed a hydroxyapatite (HAp) layer on/in certain types of nonionic hydrogels that contain hydroxyl groups. The hydrogels used were poly(vinyl alcohol) (PVA), poly(2-hydroxyethyl methacrylate) (PHEMA), poly(glucosyloxyethyl methacrylate) (PGEMA), and agarose. Under an optical microscope, we observed a thin, continuous HAp layer on the top surface of the PVA, PHEMA, and PGEMA gels. On the other hand, we only observed an intermittent HAp layer on the surface of the agarose gel. The swelling ratio and the bound water content of these hydrogels were measured as an essential character in HAp formation. There was some relation among the HAp formation, the swelling ratios, and the bound water content.

Intraoperative crystallization on the intraocular lens surface

PURPOSE

To report a physician survey, laboratory studies, and clinical observations of intraoperative crystallization on the surface of the intraocular lens (IOL).

METHOD

We sent a survey to all ophthalmologists in the states of Wyoming, Idaho, Montana, Utah, and Colorado asking whether crystallization on the IOL surface had occurred in any of their patients and what viscoelastics, IOLs, and other solutions were used. All returned surveys were tabulated and analyzed by standard statistical means. A sample of crystallization from an IOL on a glass slide submitted by a physician was analyzed to ascertain the relative elemental composition. During in vitro laboratory studies, BSS Plus (Alcon Surgical, Fort Worth, Texas) and BSS (Alcon Surgical) were measured and analyzed for precipitation. Healon GV (Pharmacia/Upjohn, Kalamazoo, Michigan) and calcium chloride were combined in various solutions and examined for precipitate formation. Silicone IOLs and plate silicone were placed in different BSS and BSS Plus solutions with different viscoelastics and varying calcium concentrations. In seven patients, prominent crystallization on an IOL surface was examined, photographed, and followed for up to 3 years.

RESULTS

Two hundred six surveyed ophthalmologists returned 181 surveys (88%) and reported 29,609 cataract surgeries, with IOL implantation with 22 eyes (0.07%) (22 patients) in which intraoperative crystallization was observed on the IOL surface during 1993. The survey indicated there was a correlation with BSS Plus (chi-square = 4.9, P = .0268) and silicone IOLs (chi-square = 6.8, P = .0093). The sample showed the cation to be calcium.

CONCLUSION

Crystallization on the IOL surface during cataract surgery is a rare occurrence that may be associated with calcium as the cation related to an osmotic gradient around the IOL with increased calcium concentration. If encountered surgically, the lens should be exchanged in the operating theater after irrigating the anterior chamber with BSS and completely filling the capsular bag with a low molecular weight viscoelastic.