Modified technique to improve fabrication and outcome of definitive orbital prosthesis

Facial prostheses are generally fabricated from silicones, which provide life-like appearance and flexibility. The longevity of silicone, however, is limited because of its tendency to support fungal growth, absorb oils and grease, and edge-tearing susceptibility. Polyurethane (PU) liners have been used on the tissue-bearing surface of such prosthesis to improve tear resistance and fungal resistance. Technique sensitivity, discoloration and metamerism are significant limitations of urethane lining. Further, this liner is incorporated during processing of definitive prosthesis, which precludes try-in of tissue surface of prosthesis. This article describes an alternative lining material for fitting surface of definitive orbital prostheses, which could overcome limitations associated with all silicone or PU lined silicone prostheses.

Reconstruction of large facial and orbital defects by combining free flap transfer with craniofacial prosthesis

The reconstruction of complex craniofacial and orbital defects should satisfactorily restore functional and aesthetic integrity. Autologous reconstruction of nasal, periorbital and auricular facial subunits as a whole using a locoregional or a free flap is very challenging and the results are not sometimes ideal. With advanced technologies that are currently available it is possible to plan and produce authentic facial prosthesis that can satisfactory substitute these facial subunits. We demonstrate an alternative reconstructive concept for complex craniofacial defects based on a free flap combined with a facial prosthesis for the replacement of periorbital or auricular facial subunits. This approach was used in two patients with very satisfactory results. Combination of a free flap with a facial prosthesis may become a preferable approach for the reconstruction of complex craniofacial defects. Clinical outcomes of the reconstructions may be enhanced respecting the principle of aesthetic facial subunits.

A biomimetic collagen/heparin multi-layered porous hydroxyapatite orbital implant for in vivo vascularization studies on the chicken chorioallantoic membrane

BACKGROUND

The vascularization of an orbital implant is a key issue for reducing complications, such as exposure and infection.

METHODS

Here, we developed a facile layer-by-layer assembly approach to modify porous hydroxyapatite (pHA) orbital implants with five collagen (COL)/heparin (HEP) multilayers.

RESULTS

SEM characterization showed that the average pore size of the pHA/(COL/HEP)5 scaffold was 316.8 ± 77.1 μm. After being coated with five COL/HEP multilayers, the mechanical strength was improved compared with that of the pHA scaffolds. The in vitro assay displayed that the pHA scaffolds covered with COL/HEP multilayers resulted in a larger number of human umbilical vein endothelial cells after being cultured for 14 days. The macroscopic evaluation and semi-quantitative vascular density analysis of the chicken chorioallantoic membrane assay showed that the pHA/(COL/HEP)5 scaffolds resulted in more intense angiogenesis than the pHA scaffolds.

CONCLUSIONS

These studies demonstrate that the biomembrane-mimicking coating of COL/HEP multilayers is a simple and effective strategy to endow combined biological performances of pHA orbital implants and to potentially reduce implant-related complications.

[Anophthalmia and microphthalmia requires multidisciplinary care. Many of the children also have other medical problems]

Anophthalmia/microphthalmia (A/M) are rare congenital eye malformations. Early intervention with ocular prosthesis can stimulate orbital growth and prevent facial asymmetry. We reviewed medical records from 18 individuals with A/M (0.8-31 years) treated with ocular prosthesis at Sahlgrenska University Hospital between 2000 and 2012. A majority had other ocular findings. Seven had subnormal visual acuity in the fellow eye, one third were in contact with vision support services and half of the group wore glasses. Eleven individuals had extra-ocular findings such as cardiac defect, hearing impairment and neuropsychiatric disorders, possibly indicating syndromic conditions. We suggest that investigation of A/M children should include ultrasound of the eye, optionally visual evoked potential and magnetic resonance imaging of the CNS. The ophthalmologist should initiate treatment with prosthesis, pediatric assessment, hearing tests and genetic counseling, but should also monitor visual development of the fellow eye.

A Novel Bioresorbable Implant for Repair of Orbital Floor Fractures

PURPOSE

To describe clinical, radiologic, and safety outcomes of orbital floor fracture repair using a novel bioresorbable polycaprolactone (PCL) mesh implant (Osteomesh™, Osteopore International, Singapore).

METHODS

This is a prospective interventional case series of orbital floor fractures repaired using a novel PCL mesh implant. Clinical evaluation was conducted at presentation and postoperatively at 1, 4, 12, 24 and 48 weeks. Computed tomography (CT) of the orbits was performed 1 year postoperatively.

RESULTS

A total of 20 patients were recruited. Mean follow up was 50.4 ± 31.88 weeks. The majority of the patients were male (60%) and of Chinese ethnicity (75%), and the mean age was 39.35 (range 13-69) years. The most common mechanism of injury was assault. The average fracture size was 21.9 mm (range 12-32 mm) in the anteroposterior meridian and 18.65 mm (range 6-27 mm) in the horizontal meridian. Fifty percent of the patients were classified as having a large orbital defect (horizontal width ≥20 mm). The binocular single vision (BSV) score improved from 72.1% preoperatively to 90.8% postoperatively (P < 0.05) for 17 patients who had pre and postoperative charts. BSV improvement did not differ significantly between those with large and small orbital fracture sizes. There were features of neobone formation on CT scan performed 1.5 years after implantation.

CONCLUSION

This bioresorbable implant is a promising material for the repair of both small and large orbital floor fractures, giving good functional and aesthetic outcomes.

In vitro and in vivo imaging of ultra-high-molecular-weight polyethylene orbital implants

The aim of this study is to compare magnetic resonance imaging (MRI) with computed tomography (CT) for visualization of an orbital alloplastic prosthesis made of ultra-high-molecular-weight polyethylene (UHMW-PE) both in vitro and in vivo. A study of 15 test implants from UHMW-PE visualized in vitro in CT and MRI and an in vivo visualization in a patient who suffered from orbital injury and underwent reconstructive surgery is presented. The postsurgery MRI showed the UHMW-PE material clearly, with no significant artifacts. The surrounding tissues could be satisfactorily evaluated. The CT scans did not present the graft material. Both techniques were sufficient tools for in vitro evaluation of the shape and measurement of the prosthesis.

Hydroxyapatite ocular implant and non-integrated implants in eviscerated patients

INTRODUCTION

This study compares the outcomes and complications of hydroxyapatite ocular implant and non-integrated ocular implants following evisceration.

MATERIALS AND METHODS

This is a retrospective study of 90 patients who underwent evisceration for different ocular affections, in the Ophthalmology Department of the University Emergency Hospital Bucharest, between January 2009 and December 2013. The outcomes measured were conjunctival dehiscence, socket infection, implant exposure and extrusion rate.

RESULTS

Forty-three patients had the hydroxyapatite implant (coralline-Integrated Ocular Implants, USA or synthetic-FCI, France) and forty-seven received non-integrated ocular implants (24 acrylic and 23 silicone). Five cases of socket infection, thirteen cases of extrusion and two cases of conjunctival dehiscence were encountered.

CONCLUSIONS

There was a higher rate of conjunctival dehiscence with hydroxyapatite ocular implant, but implant extrusion and socket infection were found in non-integrated ocular implants.

Prosthetic Management and Analysis of Combined Extraoral-Intraoral Maxillofacial Defects Complicated with Microstomia. A Report of Three Cases

Different prosthetic treatment plans for three patients with variable degrees of acquired maxillofacial defects were reported and analyzed. Combined extraoral-intraoral prostheses were selected to restore the three cases. Two patients were rehabilitated using two separated prostheses, while the third one was restored with a coupled two-unit prosthesis. The design of extraoral-intraoral prosthesis either separated or connected, is influenced by the condition and nature of the residual tissues, defect configuration, patient needs, degree of tissue damage and the anticipated success rate or complications with the treatment. It was observed that separating the intraoral part from that of the extraoral resulted in better retention, stability, and more comfort to the patient with combined defects. Furthermore, fabrication and repair of each part is technically easier as perceived it can be carried out independently and the patient can continue to use one-part and send the other for repair. Another advantage is the reduction of size and weight of the prosthesis.

[Three-dimensional finite element analysis of the effect of orbital implant lengths on stress distributions in peri-implant surfaces]

OBJECTIVE

This study aims to observe the effect of orbital implant lengths on stress distribution in peri-implant surfaces.

METHODS

The three-dimensional finite element analysis models of craniofacial and orbital implants with a diameter of 3.75 mm and lengths of 3, 4, 6, and 10 mm were established. A force of 20 N was applied to the models. The stress and displacement distribution under every condition were recorded and analyzed.

RESULTS

The loading direction along the implant axis and the stress concentration on the implant root were observed. The loading direction was at a 45 degree angle relative to the implant axis, and the stress concentration was located at the implant neck and the first screw thread. The maximum stress of the 3 mm implant was significantly higher than that under the other two loading directions. The maximum displacement of the four lengths exhibited no significant change. Given the same implant length, stress, and displacement, the peak of the implant axial direction was lower than that of the 45 degree direction. The loading type was an important factor influencing the stress and displacement of peri-implant bones.

CONCLUSION

The implants of more than 4 mm length can be considered for clinical use. The implant of 3 mm length should be implanted in a region with thicker cortical bone.

[Three-dimensional finite element analysis of the effect of orbital implant lengths on stress distributions in peri-implant surfaces]

OBJECTIVE

This study aims to observe the effect of orbital implant lengths on stress distribution in peri-implant surfaces.

METHODS

The three-dimensional finite element analysis models of craniofacial and orbital implants with a diameter of 3.75 mm and lengths of 3, 4, 6, and 10 mm were established. A force of 20 N was applied to the models. The stress and displacement distribution under every condition were recorded and analyzed.

RESULTS

The loading direction along the implant axis and the stress concentration on the implant root were observed. The loading direction was at a 45 degree angle relative to the implant axis, and the stress concentration was located at the implant neck and the first screw thread. The maximum stress of the 3 mm implant was significantly higher than that under the other two loading directions. The maximum displacement of the four lengths exhibited no significant change. Given the same implant length, stress, and displacement, the peak of the implant axial direction was lower than that of the 45 degree direction. The loading type was an important factor influencing the stress and displacement of peri-implant bones.

CONCLUSION

The implants of more than 4 mm length can be considered for clinical use. The implant of 3 mm length should be implanted in a region with thicker cortical bone.

Remove, rotate, and reimplant: a novel technique for the management of exposed porous anophthalmic implants in eviscerated patients

PURPOSE

To describe and to evaluate a new and relatively easy technique for porous implant exposure repair.

METHODS

Eleven patients with exposed porous orbital implants after evisceration were included in this study. Five patients with large exposures (diameter >7 mm) and six patients with small exposures of orbital implants (diameter <7 mm) that persisted despite posterior vaulting of the prosthesis and usage of antibiotics and steroids for more than 6 weeks, underwent revision surgery with the remove-rotate-reimplant technique (3R technique). Negative microbiological culture taken from the exposed socket surface before surgery was the major inclusion criterion. Five patients with insufficient conjunctival tissue also underwent additional mucosa or hard palate grafting of the defect in addition to the remove-rotate-reimplant procedure.

RESULTS

Patients have been followed up for more than 18 months (ranging from 18-30 months). None of them received motility peg insertion after repair. Implant reexposure was detected in one patient during the follow-up period, which was managed by dermis fat grafting with implant removal.

CONCLUSION

The remove-rotate-reimplant technique is an effective surgical method for repairing exposed porous anophthalmic implants after evisceration with a 90% success in this study. It avoids the removal of the implant from the sclera, which is a traumatic procedure that may lead to the tearing and loss of scleral tissue covering the implant. Saving the porous implant and scleral cover reduces the surgical time and cost.

Porous orbital implant exposure: the influence of surgical technique

OBJECTIVES

To examine orbital implant exposure rates following enucleation and evisceration.

METHODS

A retrospective chart review of all patients who underwent an evisceration or enucleation in a single centre over a 5-year period was performed. The indication for surgery, the type and size of orbital implant used, details of the surgical technique adopted and the postoperative complications observed, in particular orbital implant exposure, were recorded.

RESULTS

Over a 5-year period 24 patients had enucleation and 14 had evisceration; 22 of these procedures were performed by an ophthalmic surgeon with a special interest in orbit and oculoplastics while the remaining 16 procedures were performed by 5 ophthalmic surgeons with other sub-specialty interests. Orbital implant exposure occurred in 8 cases. One case had been performed by the first of these surgeons described. Implant exposure occurred in 4% of cases performed by this surgeon. The remaining 7 cases had been performed by the group of surgeons with sub-specialty interests outside of orbit and oculoplastics. Implant exposure occurred in 48% of cases performed by this group.

CONCLUSIONS

Orbital implant exposure remains a significant cause of morbidity in patients undergoing enucleation and evisceration. Rates of orbital implant exposure were significantly lower when surgery was performed by an orbital surgeon. Differences in surgical technique are the most likely explanation.

Enucleation in Iceland 1992-2004: study in a defined population

PURPOSE

To determine the incidence rate as well as causative diagnoses and surgical indications of enucleation in Iceland during the years 1992-2004.

METHODS

A retrospective population-based incidence study involving the entire population of Iceland. Medical records of all patients who underwent enucleation in Iceland from January 1992 through December 2004 were reviewed. The annually updated Icelandic census was used as a denominator data.

RESULTS

Fifty-six eyes were enucleated during 1992-2004. No eviscerations were done, and the three exenterations performed were not included in the study. The mean annual age-adjusted incidence rate of enucleation in Iceland was 1.48 enucleations per 100 000 population in comparison with 2.66 enucleations per 100 000 for the time period 1964-1991. With advancing age, a significant increasing linear trend existed (p < 0.001). The median age at enucleation was 51 years (SD 22; mean 55 years; 16-91 years). The three most common surgical indications for enucleation were blind painful eye, suspected ocular malignancy and acute trauma. The most common causative diagnosis for enucleation was traumatic lesion (39%). The annual incidence was 2.00 enucleations per 100 000 for men and 0.95 for women. There were significantly more men in the traumatic lesion group (p < 0.001), but no gender predominance was found in the other groups of causative diagnoses (p = 0.8).

CONCLUSION

The overall mean annual incidence of enucleation in Iceland is continually decreasing, although the incidence of severe ocular trauma and ocular malignancy is fairly stable.

[Effects of basic fibroblast growth factor composite sponge treated collagen on vascularization of orbital implants: a histopathologic analysis]

OBJECTIVE

To evaluate the effect of basic fibroblast growth factor (bFGF) treated collagen composite sponge on vascularization of HA orbital implants.

METHODS

New Zealand rabbits received three different orbital implants:naked implants, implants wrapped with collagen composite sponge and implants wrapped with bFGF treated collagen composite sponge.Implants were harvested 2, 4, 6, 8 and 12 weeks after surgery. The vascularization of implants was then assessed by light and electron microscopy.

RESULTS

At post-surgery weeks of 2, 4 and 6, bFGF treated collagen composite sponge induced the highest degree of vascularization of orbital implants. Collagen composite sponge alone resulted in higher extent of vascularization than naked implants. Complete vascularization of implants was observed at post-surgery 6 weeks by bFGF treated collagen composite sponge, which was not observed in the other two groups until post-surgery 8 weeks. There were significant differences in the average length of fibrovasculature and in the degree of vascularization among each group at post-surgery 2, 4 and 6 weeks (P<0.05), while no statistical difference was observed at post-surgery 8 and 12 weeks (P>0.05).

CONCLUSIONS

bFGF treated collagen composite sponge facilitates fibrovascularization of orbital implants, and shortens the time required for complete vascularization. Collagen composite sponge alone promotes early-stage fibrovascularization, but fails to facilitate complete vascularization of orbital implants.

Biomaterials for orbital implants and ocular prostheses: overview and future prospects

The removal of an eye is one of the most difficult and dramatic decisions that a surgeon must consider in case of severe trauma or life-threatening diseases to the patient. The philosophy behind the design of orbital implants has evolved significantly over the last 60 years, and the use of ever more appropriate biomaterials has successfully reduced the complication rate and improved the patient's clinical outcomes and satisfaction. This review provides a comprehensive picture of the main advances that have been made in the development of innovative biomaterials for orbital implants and ocular prostheses. Specifically, the advantages, limitations and performance of the existing devices are examined and critically compared, and the potential of new, smart and suitable biomaterials are described and discussed in detail to outline a forecast for future research directions.

Orbital implants: potential new directions

This article reviews orbital implants used to replace an eye after enucleation or evisceration. Advantages of implant placement are described, with discussion of implant and wrap material, and design features that affect clinical outcomes. Implants may be porous or nonporous, pegged for linkage with a cosmetic shell or unpegged, and may be wrapped with a covering material or tissue or unwrapped. Device shape, volume and material qualities affect tissue tolerance and the risk of exposure or extrusion. Limitations of currently available devices are discussed, with factors affecting surgeon and patient choice. Ideally, a device should be easy to insert, avoid the need for wrapping or adjunctive tissues, be light, biointegratable, comfortable after implantation and provide satisfactory orbital volume replacement, movement and cosmesis without requiring further surgery or pegging. This review briefly discusses developments in implant design and aspects of design that affect function, but is not a detailed clinical review; rather, it aims to stimulate thought on optimal design and discusses recent developments. Novel technology in the form of a prototype device with a soft, biointegratable anterior surface is described as an example of newer approaches.

Use of extraocular muscle flaps in the correction of orbital implant exposure

Purposes

The study is to describe a new surgical technique for correcting large orbital implant exposure with extraocular muscle flaps and to propose a treatment algorithm for orbital implant exposure.

Methods

In a retrospective study, seven patients with orbital implant exposure were treated with extraocular muscle flaps. All data were collected from patients in Chang Gung Memorial Hospital, Taiwan during 2007–2012. All surgeries were performed by one surgeon (Y.J.T). Patient demographics, the original etiology, details of surgical procedures, implant types, and follow-up interval were recorded. Small exposure, defined as exposure area smaller than 3 mm in diameter, was treated conservatively first with topical lubricant and prophylactic antibiotics. Larger defects were managed surgically.

Results

Seven patients consisting of two males and five females were successfully treated for orbital implant exposure with extraocular muscle flaps. The average age was 36.4 (range, 3–55) years old. Five patients were referred from other hospitals. One eye was enucleated for retinoblastoma. The other six eyes were eviscerated, including one for endophthalmitis and five for trauma. Mean follow-up time of all seven patients was 19.5 (range, 2–60) months. No patient developed recurrence of exposure during follow-up. All patients were fitted with an acceptable prosthesis and had satisfactory cosmetic and functional results.

Conclusions

The most common complication of orbital implant is exposure, caused by breakdown of the covering layers, leading to extrusion. Several methods were reported to manage the exposed implants. We report our experience of treating implant exposure with extraocular muscle flaps to establish a well-vascularized environment that supplies both the wrapping material and the overlying ocular surface tissue. We believe it can work as a good strategy to manage or to prevent orbital implant exposure.

Alphasphere as a successful ocular implant in primary enucleation and secondary orbital implant exchange

PURPOSE

To describe the surgical technique for a novel poly-HEMA (2-hydroxyethyl methacralate)[PHEMA] implant (Alphasphere, Addition Technology, Des Plaines, IL) in primary enucleation and placement of secondary orbital implant.

METHODS

Retrospective chart review of all patients receiving an Alphasphere implant for primary enucleation or secondary implant exchange from October 2009 to 2011. Interval follow-up was performed again on January 2013. Patient demographics, indications for surgery, and post-operative complications were reviewed.

RESULTS

Twelve patients received an Alphasphere implant for primary enucleation (n = 10) or secondary exchange (n = 2), with follow-up that ranged from 2 weeks to 14 months. The study included 9 adult and 3 pediatric patients with a mean age of 40 years, range 8-82 years. The indication for enucleation included: painful blind eye (n = 9), enophthalmos with difficult prosthesis fit in cases of secondary implant exchange (n = 2), and prophylaxis for sympathetic ophthalmia (n = 1). Only one patient required removal of the implant, due to a sinus infection with subsequent extrusion of the implant. Otherwise, the only other complication experienced was slight implant migration (n = 1).

CONCLUSION

This initial report indicates that Alphasphere can be successfully used in the management of an anophthalmic socket. The advantages of the Alphasphere implant include: it does not require tissue wrapping, extraocular muscles can be directly sutured to the implant, it maintains a smooth surface to limit risk of exposure due to conjunctival breakdown, and undergoes anterior orbital fibrovascular ingrowth which optimizes prosthesis location and socket motility.

Intracranial arachnoid cyst; an unusual cause of epiphora

PURPOSE

To describe a case of unilateral intracranial arachnoid cyst in association with enophthalmos and epiphora on the same side.

METHODS

Case report.

RESULTS

A young man with symptoms of unilateral epiphora is described. He had a large intracranial arachnoid cyst with an unusually large orbit leading to enophthalmos and symptomatic epiphora on that side. Radiological features of the orbit and associated pneumosinus dilatants are described. We also offer hypotheses to describe the paradoxical occurrence of an expanding intracranial mass and inward growth of the orbit and paranasal sinuses.

CONCLUSION

A new cause for enophthalmos is described.

Desmoplastic fibroma: report of rare lesion in unusual craniofacial location

Desmoplastic fibroma (DF) is a benign but aggressive intraosseous tumor. These lesions are categorized as central tumors of bone. They are composed of small fibroblasts in a setting of abundant extracellular material, which is rich in collagen. DF represents fewer than 0.1% of all bony tumors. They can be found in any part of the skeleton. Based upon on our literature review, we believe this is the second reported case of desmoplastic fibroma occurring in the zygoma area.

[Implants in ophthalmology and potential of visual control]

Results of complex ultrasonic examination in different time after socket reconstruction using biomaterial "Alloplant" are presented. Modified technique of primary socket reconstruction showed good cosmetic result.

[Surgical rehabilitation in patients with zygomatic orbital fractures and orbital floor fractures]

The study presents the results of surgical management of 65 patients with zygomatico-orbital complex and orbital floor fractures according to a self-designed technique using polymer implants Reperen. Being a method of choice the technique reduces treatment time, promotes good esthetic results, reduces complication rate, and contributes to a patient's quality life improvement.

Measurement of orbital volume after enucleation and orbital implantation

Introduction

This article reports experience relating to the measurement of orbital volume by means of cone beam computed tomography (CBCT) and Cranioviewer program software in patients who have undergone enucleation and orbital implantation.

Patients and Methods

CBCT scans were made in 30 cases, 10 of which were later excluded because of various technical problems. The study group therefore consisted of 20 patients (8 men and 12 women). The longest follow-up time was 7 years, and the shortest was 1 year. In all 20 cases, the orbital volume was measured with Cranioviewer orbital program software. Slices were made in the ventrodorsal direction at 4.8 mm intervals in the frontal plane, in both bony orbits (both that containing the orbital implant and the healthy one). Similar measurements were made in 20 patients with various dental problems. CBCT scans were recorded for the facial region of the skull, containing the orbital region. The Cranioviewer program can colour the area of the slices red, and it automatically measures the area in mm.

Results

In 5 of the 20 cases, the first 4 or all 5 slices revealed that the volume of the operated orbit was significantly smaller than that of the healthy orbit, in 12 cases only from 1 to 3 of the slices indicated such a significant difference, and in 3 cases no differences were observed between the orbits. In the control group of patients with various dental problems, there was no significant difference between the two healthy orbits. The accuracy of the volume measurements was assessed statistically by means of the paired samples t-test.

Summary

To date, no appropriate method is avaliable for exact measurement of the bony orbital volume, which would be of particular importance in orbital injury reconstruction. However, the use of CBCT scans and Cranioviewer orbital program software appears to offer a reliable method for the measurement of changes in orbital volume.