Technical Information

Literature Review
MEDPOR® Biomaterial and Porex Surgical Products

Orbital Reconstruction

McCord, C.D., Ford, D.T., et al, “Lateral Canthal Anchoring: Special Situations” Plastic and Reconstructive Surgery, Vol. 116, No 4, pp1149-1157 (Sept 2005)

The incorporation of lateral canthal anchoring into cosmetic or reconstructive surgery of the lower eyelids is commonly accepted.1-5 In a previous article, we showed how lateral canthal anchoring by means of canthopexy, canthoplasty, or lateral orbicularis suspension allows the surgeon to control eye fissure shape, preserve eyelid blinking, and help prevent or correct postoperative lower lid malposition. The techniques described in that article will serve the surgeon well in most situations. However, in selected reconstructive procedures, and in patients with prominent eyes, an alternate approach is needed to obtain proper eye fissure shape and good eyelid closure. This method involves anchoring the superior and inferior lateral tarsus to the lateral orbital rim in a criss-cross vector fashion. The technique was developed in response to the observed distortion and impairment of eyelid closure when lateral canthal supraplacement was used in prominent eyed patients. This approach emphasized the importance of both upper and lower lid anchoring in attaining normal eyelid closure. The criss-cross vector anchoring principle is important in reoperative cases, but also should be recognized in patients undergoing primary surgery that would benefit from this approach.

This abstract is provided for educational purposes only. It contains information about cleared uses of the product. It may contain other potential uses not cleared by the Food and Drug Administration and not advocated by the manufacturer. The uses and opinions expressed within the article are those of the author derived from his or her personal experience with the product. For additional information on cleared product specific indications and to request a copy of the cleared labeling please contact the manufacturer's customer care department.

Lee. S., Maronian, N., Most, S.P., Whipple, M.E., et al “Porous High-Density Polyethylene for Orbital Reconstruction” Arch Otolaryngol Head Neck Surgery. Vol. 131, pp446-450 (May 2005)

Objective: To determine the safety and efficacy of using porous high-density polyethylene (PHDPE) in the repair of orbital defects.

Design: Retrospective case series.

Setting: Academic tertiary care trauma center.

Patients: One hundred seventy patients with orbital defects requiring surgical repair.

Intervention: Orbital defect repair with PHDPE.

Main Outcome Measure: Our review documents surgical results and complications associated with the use of PHDPE.

Results: There was a 6.4% complication rate associated with the use of PHDPE. The infection rate was 1.8%. The persistent orbital malposition rate was 3.5%. The extrusion rate was 0%.

Conclusions: This report represents the largest case series in the literature using PHDPE for orbital reconstructions. The use of PHDPE resulted in a low complication rate and excellent functional and cosmetic reconstructive results. Because of our success with the use of PHDPE, we have changed our clinical practice to minimize the use of autologous graft material, thereby eliminating donor site morbidity in cases involving orbital reconstruction.

Hart, R.; Barnes, E.; Dickinson, A.J.; “Secondary Orbital Implants After Evisceration: A New Conjunctiva-Sparing Technique,” Ophthalmic Plastic and Reconstructive Surgery, Vol. 21 No. 2 pp129-132 (March 2005)

Purpose: To describe a new conjunctiva-sparing technique for secondary orbital implantation after evisceration.

Methods: Two patients with conjunctival cicatrization and a volume-deficient anophthalmic socket had implantation of an intraconal biointegratable implant. This was placed through a lateral canthal approach, after temporary disinsertion of the lateral rectus, thereby avoiding further injury to the conjunctival.

Results: A good surgical outcome was achieved in both patients. There were no intraoperative or postoperative complications, and both have remained stable for nearly 2 years.

Conclusions: Secondary intraconal implantation through the lateral canthal approach is safe and effective and suitable for patients in whom it is desirable to avoid a conjunctival incision

Merbs, S.L., Iliff, N.T., Grant, M.P., Garibaldi, D.C., “Use of the MEDPOR TITAN Implants in Orbital Reconstruction.” Poster presented at ARVO, Fort Lauderdale, Florida (May 2005)

Poster

Ophthalmology, Wilmer Eye Institute, Baltimore, MD

Commercial Relationships: S.L. Merbs, Porex Surgical, Inc. F; N.T. Iliff, Porex Surgical, Inc. F; M.P. Grant, Porex Surgical, Inc. F; and D.C. Garibaldi Porex Surgical, Inc. F.

Support: None.
Purpose: Both MEDPOR® polyethylene and titanium mesh have been successfully used for orbital reconstruction. Titanium mesh has the advantage of a high tensile strength, memory after shaping, and radio-opacity allowing it to be seen on post-operative CT scans. However, titanium implants can be difficult to insert because of sharp points after shaping and orbital tissues, including extraocular muscles, can adhere to the mesh. BARRIER MEDPOR polyethylene implants have a smooth surface to face orbital tissues, preventing adherence and a porous surface to allow tissue ingrowth. However, MEDPOR implants have less tensile strength, are not as easy to shape, and are not seen on post-operative scans. We have examined the effectiveness of a new orbital implant, which combines the benefits of both MEDPOR polyethylene and titanium mesh, in the reconstruction of orbital defects.
Methods: In a retrospective, non-comparative case series, we evaluated 12 consecutive patients who had placement of at least one MEDPOR TITAN plate during orbital reconstruction preformed by the authors since October 2004. Surgeons were questioned as to the advantages and disadvantages of the novel implant. Patient charts and pre-operative and post-operative scans were reviewed for any complications associated what the implants.
Results: 10 males and 2 females underwent placement of a MEDPOR TITAN implant. Patient ages ranged from 3 to 73. 10 patients had acute fracture repair (7 floor fractures, 2 medial wall fractures, and 1 floor and medial wall fracture) an average of 7 days after injury; 1 patient had late enophthalomos repair; and 1 patient had orbital reconstruction after tumor removal. Both MTB (MEDPOR TITAN BARRIER) and BTB (MEDPOR TITAN Double BARRIER) implants were used and were typically fixated with 1 or 2 microscrews. Surgeons reported that the implants were easy to shape, had sufficient tensile strength to maintain their contour, and were well-visualized on post-operative CT scans. No short-term complications were noted, and patients continue to be followed for evidence of long-term complications.
This abstract is provided for educational purposes only. It contains information about cleared uses of the product. It may contain other potential uses not cleared by the Food and Drug Administration and not advocated by the manufacturer. The uses and opinions expressed within the article are those of the author derived from his or her personal experience with the product. For additional information on cleared product specific indications and to request a copy of the cleared labeling please contact the manufacturer's customer care department.

Holck, David E. E.; Dahl, Thomas, Wilford Hall Medical Center, San Antonio, Texas; Foster, Jill, A., Ophthalmic Consultants of Ohio, Columbus, Ohio; Ng, John D., Casey Eye Institute, Oregon Health Sciences Center, Portland, Oregon, “Internal Orbital Wall Fracture Repair Using Porous Polyethylene/ Titanium Mesh (MEDPOR® TITAN™) Implants,” 2005

Introduction: The complex nature of bony orbital fractures and their impact upon orbital soft tissue structure and visual function presents a particular challenge to the orbital surgeon. The tenants of surgical management of symptomatic orbital fractures involve open reduction of the fracture, release of the entrapped tissues, repositioning of the herniated orbital soft tissue within the orbit, and repair of the post-traumatic defect with an orbital implant as needed. The orbital implant restores the structural integrity of the orbital wall by bridging the defect and preventing orbital contents from herniating into the adjacent periorbital sinuses. The implant should prevent extra-ocular motility limitations by minimizing scar tissue adhesion with orbital contents. These implants can also serve to augment the orbital volume by compressing the intraorbital contents to correct enophthalmos. Current implants include autogenous grafts, human donor grafts, xenografts and alloplastic implants. The ideal alloplastic implant has been described as readily sizeable, sterilizable, strong, inert, non-allergenic, durable, non-carcinogenic, easily manipulated and shaped, and suitable for single stage reconstruction. Implants should be accepted and well integrated into the surrounding tissues with minimal inflammatory response, foreign body reaction, or risk of infection. The implant should provide mechanical support strong enough to hold up the orbital contents, and have the ability to be easily anchored to the surrounding bone to prevent migration and extrusion. Finally, it should be readily available in larger quantities if necessary, at a reasonable cost.

Porous polyethylene orbital sheets offer strength and stability, with porous channels that allow fibrovascular ingrowth. The implants exhibit memory upon bending, which must be considered during placement in the orbit. Fenestrated and mesh titanium implants also allow excellent strength and stability characteristics without memory after the material has been conformed to fit the orbital contours and defect. However, removal of the implant can prove to be a difficult task once tissue ingrowth has occurred. Scarring to the exposed metallic mesh with dysmotility is an additional reported complication.

Recently, a porous polyethylene sheet with titanium mesh has been available for use in non-weight bearing applications as seen with internal orbital fractures (TITAN implants, Porex Surgical, Newnan, GA, USA). We evaluated the utility of this material in large floor and combined floor/ medial wall fractures.

To view the entire white paper with images of cases studied, click here.

Kun Hwang, MD, PhD, Sun Goo Kim, MD, Se II Lee, MD, DMSc, Yoon Ha, MD, “Blepharoptosis Caused from Compression of Levator Muscle by Fractured Orbital Roof Fragment,” The Journal of Craniofacial Surgery, Volume 15, Number 6, November 2004

The authors report two cases of blepharoptosis caused by compression of the levator muscle by fractured orbital roof fragment; both were improved by surgical treatments. In one case, because neurosurgeons were concerned with the contusional hemorrhage of the right frontal lobe during the early admission period, they missed the orbital roof fracture. The patient underwent surgery on the 18th post-trauma day. In the other case, the early diagnosis was made, and the surgical treatment was performed on the 10th post-trauma day. The authors think if the blepharoptosis is not improved in several days and the fractured fragment is suspected to compress the levator in computed tomography scan, surgical decompression is necessary and should be performed as soon as possible.

Strong E.B., “Endoscopic Repair of Orbital Blow-Out Fractures” Facial Plastic Surgery, Vol 20, No 3, pp223-230 (August 2004)

Orbital floor blow-out fractures (OBFs) result from trauma to the globe and periorbita. These fractures occur in repeatable patterns that can be endoscopically classified as either medial or lateral to the infraorbital nerve (V2). Medial fractures are the most common and can be separated into “trap door” and “blow-out” fractures. Fractures that extend lateral to V2 are generally higher velocity injuries that result in comminution of the entire orbital floor. The key to successful surgical repair of these injuries is adequate exposure, visualization of the posterior bone shelf, and anatomic repair of the entire defect. Visualization of the posterior shelf can be challenging through traditional transconjunctival and subciliary approaches. These approaches also have known risks of postoperative eyelid malposition. The transmaxillary endoscopic approach to OBFs offers excellent visualization of the entire orbital floor. Fracture types can be evaluated and repaired endoscopically without the need for an eyelid incision. Although this is a new and evolving technique, early experience suggests that the endoscopic approach is a safe, efficacious technique for OBF repair. It offers improved visualization, anatomic fracture repair, no risk of postoperative eyelid complications, and good clinical results.

Rapidis, A.D., Liarikos, S., Ntountas, J., Patel, B.C.K., “The Silent Sinus Syndrome: A Report of 2 Cases” Journal of Oral Maxillofacial Surgeons, Volume 62, Number 8, August, 2004

Discussion: Enophthalmos and hypoglobus usually result from trauma to the orbital region, often with blowout fractures. Spontaneous enophthalmos without prior history of trauma is rare. In 1964, Montgomery presented the cases of two patients in whom the development of enophthalmos was associated with the presence of mucoceles in the maxillary sinus. The impact of mucoceles and chronic sinusitis on the thin osseous floor of the orbit has been established in several studies.

Methods: Wilkins and Kulwin reported the effect of chronic maxillary sinusitis on the development of spontaneous enophthalmos. They studied five patients in whom asymptomatic enophthalmos appeared to develop after a long period of chronic sinusitis. The development of asymptomatic spontaneous enophthalmos associated with either the presence of maxillary mucoceles or chronic sinusitis was reported infrequently by several authors.

Results: In an effort to clarify the etiology of this peculiar syndrome Soparkar, et al., presented the case of 19 patients with spontaneous enophthalmos and associated asymptomatic maxillary sinus disease. They proposed the term “silent sinus syndrome,” emphasizing the asymptomatic pre-existing maxillary condition as the causative agent for the enophthalmos. Soparkar and Patrinely further described the exact criteria that characterize the silent sinus syndrome, as not every patient with enophthalmos and underlying maxillary sinusitis or mucoceles should be considered as having the syndrome.

Conclusions: To classify a patient with spontaneous enophthalmos as having silent sinus syndrome, the following criteria should exist. The patient should be in the third or fourth decade of life, should have a spontaneous enophthalmos and hypoglobus in the absence of other symptoms, and the condition should be associated with a homolateral “small” rather than hypoplastic maxillary sinus with focal regions of bone-thinning and loss. Radiologic criteria include a lower and thinner orbital floor, with full opacification and being smaller, compared with the non-affected side maxillary sinus, usually with inward retraction of all sinus walls. The middle meatus adjacent to the affected sinus is usually expanded. We present two cases of the silent sinus syndrome to provide understanding of this intriguing condition.

Ellis, E. III, Messo, E., “Use of Nonresorbable Alloplastic Implants for Internal Orbital Reconstruction” Journal of Oral and Maxillofacial Surgery, Volume 62, Number 7, July, 2004

Fractures of the internal orbit are common facial injuries. They can range in size from a small crack in the floor to extensive multiple wall defects. Their diagnosis and treatment planning have been greatly improved over the past 30 years because of the wide availability of computed tomography (CT). CT allows an assessment of the location of the fracture/defect and the amount of orbital soft tissue prolapse into the adjacent sinuses.

When significant internal orbital defects are not reconstructed, malposition of the ocular globe can occur. Enophthalmos and hypoglobus are the most common consequence of internal orbital defects of the floor and/or medial wall. Surgical reconstruction of the fractured, displaced, or missing orbital walls has been shown to prevent these complications in the acute setting and restore globe position in the chronic setting.

Copcu, E., “Treatment of Coup de Sabre Deformity with Porous Polyethylene Implant,” Letter to the Editor, Plastic and Reconstructive Surgery, Volume 113, Number 2 (February 2004)

Linear scleroderma “en coup de sabre” is characterized by atrophy and furrowing of the skin of the frontoparietal region. In most cases, it occurs as a single, paramedian line that may be associated with hypoplasia of underlying structures and hemiatrophy of the face. The affected region is an ivory-colored depression that may be associated with hypoplasia of the underlying soft tissue and bone and result in facial hemiatrophy. The width of coup de sabre greatly influences its treatment. If the lesion is narrow, it can be resected and directly sutured; in the case of a wide lesion, several operative procedures, not only in coup de sabre deformity but also in atrophic scars of the face, have been described. Such procedures include excision of the affected area with direct closure or closure with a skin graft, myocutaneous flap, or microvascular free flap. A local rotation flap, soft-tissue expansion with excision of the affected area, a dermal filling flap, a local padding flap without skin resection, an autologous dermal fat graft, and use of autologous and artificial bone grafts for bony defects can also be attempted. Although many treatment modalities are reported in the literature, there are no data about treatment with porous polyethylene.

A 21-year-old female patient presented to the Department of Plastic and Reconstructive Surgery of Adnan Menderes University 40 months ago with an unilateral, atrophic, depressed, linear-shaped, discolored defect of the forehead resulting from morphea en coup de sabre of 4 years’ duration. Results of all systemic examinations of the patient were normal. There were no abnormal laboratory findings. Three-dimensional computed tomography scans showed no bone deformity. Skin ultrasonography was performed and skin thickness was lowered in the defect area. No antinuclear antibodies were found. There was no family history of a similar illness.

The defect was corrected with a porous polyethylene implant. (MEDPOR® Surgical Implants, Porex Surgical, Inc., College Park, GA) A linear, 120 X 4 X 2-mm-diameter implant was used. The implant was shaped according to the concavity of the frontal bone. With the patient under local anesthesia, an incision was made 4 mm above the frontal hairline. A pocket was prepared under the defect area. The implant was situated under the periosteum and sutured to the upper part of the periosteum. There were no early or late complications. Patient was followed up for 40 months. Excellent aesthetic results were achieved. There was no depression or discolorization in the defect area and no complaints from the patient at the 40-month follow-up.

Coup de sabre is a linear form of scleroderma found over the scalp and forehead and often extending to the upper eyelid and ala. Although the pathogenesis is not completely known, scleroderma fibroblasts have been shown to lay down more collagen in the dermis, and the epidermis is considered to be almost normal. Many operative techniques and materials have been presented for the treatment of coup de sabre deformity. One of the most often used techniques was an en bloc autologous dermal fat graft shaped to match the forehead defect. The disadvantages and complications of autologous fat grafting include the need for repeated injections of fat at the affected site because of a higher resorption rate and the risks of infection, hematoma, persistent edema, and calcification. The most serious risk of suctioned autologous fat grafting is the rare embolism leading to blindness or stroke. The ideal implant or graft material should be antigenically inert, easy to sculpt. It should mimic the color and consistency of the tissue it replaces, resist trauma, infection, and extrusion, allow for host tissue ingrowths, and be readily available without additional patient morbidity. In his study experience with 116 MEDPOR Implants, Wellisz concluded that the MEDPOR Implant is an excellent alternative to existing implant materials. The implant is easy to shape, strong yet somewhat flexible, and remarkably stable, and it exhibits tissue ingrowth into its pores. Our report is the first to use this implant in the treatment of coup de sabre deformity, and our patient is one of the longest followed in the literature. We believe that porous polyethylene implants may correct the coup de sabre deformity with success.

Frodel, J.L., “Orbital Volume Augmentation for Late Enophthalmos” Letter to the Editor, Archives Facial Plastic Surgery, Volume 6, Number 1, (January/February 2004)

I read with interest the excellent article on the surgical technique that Goldberg, et a., use for the correction of late enophthalmos globe deformities. The key to the evaluation in such cases is the deepened upper eyelid sulcus that can result with unrepaired or inadequately repaired orbital fractures. The authors’ relatively simple approach, using an upper tarsal incision and placement of high-density polyethylene implants (MEDPOR; Porex, Newnan, GA) to the deep lateral wall, is an excellent concept, as it places implant material deep to the retropositioned globe, thus pushing it forward.

While Goldberg and colleagues comment that when additional volume is needed, deep medial wall augmentation may also be performed, I have concerns that the reader may come to the conclusion that this is a standard technique for the correction of enophthalmos in all patients. Not all patients with enophthalmos have an isolated blowout fracture as the cause of the globe displacement. Many patients, and the majority of those in my practice, have enophthalmos that was caused by a combination of a zygomatic fracture and an internal orbital fracture (with or without another midfacial fracture, such as a naso-orbital-ethmoidal fracture). Also, in other patients, the globe malposition may have been caused by a maxillary and/or an ethmoidal oncologic resection. Accordingly, while the malpositioned orbital floor and/or walls may be the focus of the enophthalmos, the malposition of the periorbital bony framework may contribute significantly to postinjury orbital expansion. The latter might lead not only to enophthalmos, but also to hypophthalmos.

I am certain that the authors would agree that more complex cases involving the periorbital framework generally require more extensive surgery, often including some form of osteotomy to reposition the displaced zygoma and infraorbital rim. Sometimes, augmentation with bone grafts or alloplastic materials may be sufficient, but establishing a properly positioned periorbital framework is essential to allow subsequent orbital reconstruction. As stated in the article, “Surgeons should have a flexible approach to orbital reconstruction.” However, not all cases of enophthalmos are the same, and some will require more extensive intervention than others.

It is well known that precise and complete correction of secondary orbital deformities is difficult. Some articles have even alluded to the almost obligatory requirement for multiple procedures, particularly when more than the orbit is involved. While as a reader and an orbital surgeon, I appreciate the intent of Goldberg and colleagues to present a basic and effective method for the correction of enophthalmos after blowout fractures (and I suspect even when there is minimal displacement of the periorbital framework), I am concerned that the average reader with less extensive orbital surgery experience than the authors might have a tendency to oversimplify the approach when faced with more complex globe malpositioning problems.

Regardless, I applaud Goldberg and colleagues for their excellent contribution to our facial plastic surgery literature and for describing a technique that I will certainly consider if I am confronted with a case of enophthalmos that has developed after an orbital blowout fracture.

Ganchi, P. A., Movassaghi, K., Yaremchuk, M. J., “Treatment of Bilateral Symptomatic Enophthalmos Associated with Weight Loss” The Journal of Craniofacial Surgery, Volume 15, Number 1 (January 2004)

A 31-year old male was referred by his ophthalmologist with severe bilateral enophthalmos, left greater than right. Vision and extraocular movements were normal. The cranial nerves were intact. There was entropion and eyelid trichiasis with punctate keratitis on both sides. The eyelashes were matted with mucoid drainage and the eyelids were minimally apposed to the globe secondary to the severe bilateral enophthalmos. The patient appeared macrocephalic with frontal bossing. On computed tomography, the patient had marked bilateral enophthalmos with prominent enlarged bony orbits. There was a paucity of retrobulbar fat. The orbital walls were intact. There were bilateral small maxillary sinus mucus retention cysts and enlarged sphenoid sinuses. The skull was thickened and the brain atrophied. The tip of the ventriculoperitoneal shunt was near the junction of the third ventricle and the left suprasellar cistern.

The patient was taken for corrective surgery. The surgical plan was to increase the anterior projection of the globes by decreasing the volumes of the orbits. Through a transconjunctival retroseptal approach with lateral canthotomy, the orbital contents were freed by subperiosteal dissection from the orbital apex. A combination of porous polyethylene enophthalmos wedges, channel implants, and custom-carved implants was used to create a smaller orbit behind the globe, thereby pushing the globe forward. Postoperatively, the patient did well. His enophthalmos was significantly improved, his vision and extraocular movements were intact, and his keratitis and mucoid epiphora resolved.

Su, G.W., Yen, M.T., “Current Trends in Managing The Anophthalmic Socket After Primary Enucleation and Evisceration”, Ophthalmic Plastic and Reconstructive Surgery, Volume 20, Number 4, Pages 274-280 (2004)

Purpose: To evaluate current trends in the management of the anophthalmic socket after primary enucleation and evisceration.

Methods: The active membership of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASORPS) was surveyed regarding primary enucleations and eviscerations performed between January and December 2002. Survey questions included practice demographics, orbital implant use, wrapping materials, placement of a motility peg, reasons for implant choice, and complications encountered.

Results: A total of 2,779 primary orbital implants were reported, comprising 1,919 (69.1%) enucleations and 860 (30.9%) eviscerations. The high-density porous polyethylene implant was used most frequently for enucleations (42.7%), followed by coralline hydroxyapatite (27.3%) and nonporous alloplastic implants (19.9%). For eviscerations, the high-density porous polyethylene implant was the most commonly used implant (42.3%), followed by hydroxyapatite (25.9%) and a nonporous alloplastic implant (25.7%). The top three reasons for implant choice were outcome (69.3%), cost (43.6%), and experience (39.5%). Most implants were either not wrapped (59.8%), or were wrapped in donor sclera (25.2%) or polyglactin mesh (7.2%). Pegs were used in 8.1% of all implants reported. The most frequent complications encountered for unpegged implants were exposure (3.2%) and infection (0.4%). For pegged implants, the most common complications reported were pyogenic granuloma (13.7%), exposure (5.7%) and discharge (5.7%).

Conclusions: In managing the anophthalmic socket, ASOPRS survey respondents preferred to use the porous polyethylene implant after primary enucleation and evisceration. Most orbital implants were not wrapped, and most surgeons preferred not to place a motility post or peg in the implant.

Soparkar, C.N.S., Patrinely, J.R., Stal, S., Shenaq, S.M., Marines, H.M., Klapper, S.R., Kong, J., “Successful Late Correction of Post-Traumatic Enophthalmos, Hypoglobus, and Diplopia” Presented at 2003 ASOPRS Scientific Symposium Final Program, Saturday, November 15, 2003

Purpose: To describe a series of specific soft-tissue dissection techniques developed to correct older orbital fractures (> three months old) and to determine whether this surgical approach can improve enophthalmos, hypoglobus, and ocular dysmotility.

Methods: Retrospective, single-center case series review of consecutive patients with enophthalmos and diplopia operated over a 15-year period for late repair of isolated orbital floor and/or medial wall fractures. Calibrated measurements of enophthalmos and hypoglobus were performed, and ocular dysmotility was assessed with binocular diplopia field analysis.

Results: One hundred and thirty-one patients underwent orbital fracture repair three months to 38 years after trauma (or last previous surgical intervention) and were followed for an average of 19 months. Sixty-eight percent had undergone prior orbital exploration and/or strabismus surgery. Correction was achieved to within one millimeter of desired endpoints for enophthalmos and hypoglobus repair in 93% and 97% of patients, respectively. Across all patients in this study, single, binocular visual fields expanded an average of 16 degrees in both horizontal and vertical meridians. Eighty-eight percent of patients reported subjective improvement in their diplopia and ocular function.

Conclusions: Using specific soft-tissue dissection techniques, isolated orbital fractures of the floor and/or medial wall may be repaired months to years after injury with simultaneous improvement in both globe position and extraocular muscle function.

Ho, V.H., Rowland, J.P. Jr., Linder, J.S., Fleming, J.C., “Sutureless Transconjunctival Repair of Orbital “Blowout” Fractures” Presented at the 2003 ASOPRS Scientific Symposium, Anaheim, California (November 15, 2003)
Background: Fixation of orbital implants has been previously recommended to help prevent migration or extrusion in the repair of orbital floor “blowout” fractures. Complications related to previous methods of orbital floor fracture repair include extra ocular motility restriction, eyelid retraction, and compartment syndrome from hematoma formation.

Purpose: To evaluate early post-operative results and complications in patients who underwent repair of isolated orbital floor “blowout” fractures with placement of non-fixed implants through a transconjunctival approach and closure of the conjunctival incision without sutures.

Methods: We retrospectively reviewed the charts of 26 patients who had undergone repair of isolated floor fractures of the orbit. Orbital implants (nylon or polyethylene) used in covering the defect were not fixed and no sutures were used to close the conjunctival incisions in these patients. Patients who sustained concurrent fractures of the same orbit involving other orbital bones, including the orbital rim, were excluded. Early post-operative complications including eyelid malposition, infection, and migration or extrusion of the implant, were evaluated.

Results: 26 patients (16 females, 10 males) underwent repair of isolated floor fractures and were followed post-operatively for 1 to 15 months. No eyelid malpositioning, infections, or implant extrusion occurred. However, one patient (3.8%) experienced early migration of the orbital implant that required no further intervention.

Conclusion: Repair of orbital floor blowout fractures with non-fixed implants and sutureless closure resulted in good early surgical outcomes with excellent cosmetic and functional results.

This abstract is provided for educational purposes only. It contains information about cleared uses of the product. It may contain other potential uses not cleared by the Food and Drug Administration and not advocated by the manufacturer. The uses and opinions expressed within the article are those of the author derived from his or her personal experience with the product. For additional information on cleared product specific indications and to request a copy of the cleared labeling please contact the manufacturer's customer care department.

Su, G.W., Yen, M.T., “Current Trends in Managing the Anophthalmic Socket After Primary Enucleation and Evisceration” Presented at the 2003 ASOPRS Scientific Symposium, Anaheim, California (November 15, 2003)

Purpose: To survey the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) on their techniques for managing the anophthalmic socket after primary enucleation and evisceration.

Methods: Survey questions included preferred orbital implant, preferred wrapping material, coupling of prosthetic shell with motility post or peg, and complications.

Results: 31.2% of members surveyed responded. From January through December 2002, 1913 enucleations and 832 eviscerations were performed. The three most commonly used implants for enucleations were porous polyethylene (42.7%), coral hydroxyapatite (27.3%), and acrylic/silicone spheres (19.6%). The three most commonly used implants for eviscerations were porous polyethylene (43.8%), coral hydroxyapatite (26.6%), and acrylic/silicone spheres (26.4%). Most implants were not wrapped (46.3%), wrapped in donor sclera (36.2%), or wrapped in polyglactin mesh (10.5%). Motility post or peg was placed in 8.2% of cases. The most frequent complication was exposure (3.3%).

Conclusion: The management of the anophthalmic socket after enucleation and evisceration continues to evolve. ASOPRS members seem to prefer to use unwrapped porous polyethylene implants without pegs.

Folkestad, L., Granstrom, G., “A Prospective Study of Orbital Fracture Sequelae After Change of Surgical Routines” Journal of Oral and Maxillofacial Surgery Vol. 61, Number 9 (September 2003)

Purpose: The present study was undertaken to investigate the circumstances surrounding the considerable increase in the number of orbital floor fracture repairs at the ORL Clinic at Sahlgreska University Hospital at the end of the 1990s.

Patients and Methods: All the patients during a period of one year with a fracture involving the orbital floor were followed for one year using clinical assessments and questionnaires. Etiology, surgical methods, and the occurrence of long-term sequelae were investigated.

Results: Fifty-one (51) patients were included. The main etiologies were assaults and falls. Surgery of the internal orbit was performed in 76%, often combined with a Gillies reduction. Porous polyethylene sheets (MEDPOR; Porex Surgical Inc, Newnan, GA) were used for the repair of large floor defects. Compared with previous results, the number of computed tomography investigations had considerably increased. The number of operations on the internal orbit due to fractures had doubled. The occurrence of diplopia was reduced compared with the situation when the floor was stabilized with an antral packing. Late enophthalmos developed in 11%. Despite fixation, the majority (67%) reported permanently affected sensibility.

Conclusion: The frequency and severity of diplopia decreased parallel to the introduction of MEDPOR Implants and the termination of the antral packing technique. Tetrapod zygomatic fractures, possibly unnecessarily submitted for surgery of the internal orbit, were in part responsible for the increase in the number of orbital explorations, in spite of preceding computed tomography scans. This indicates inadequate diagnostic techniques. Studies evaluating alternative complementary diagnostic methods are in progress.

Rose, G. E., Lund, V. J., “Clinical Features and Treatment of Late Enophthalmos After Orbital Decompression” Ophthalmology 110:819-826 (2003)

Purpose: To review the clinical and radiologic characteristics of a group of patients who experienced late enophthalmos after bone-removing orbital decompression. The surgical management of these patients is presented and a hypothesis proposed to explain the idiopathic “imploding antrum” (“silent sinus”) syndrome.

Design: Retrospective, non-comparative case series.

Participants: Six patients experienced relative enophthalmos, hypoglobus, and upper eyelid sulcus deformity at between three and six months after bone-removing orbital decompression for thyroid orbitopathy. Five left orbits and one right orbit were affected.

Intervention: All patients underwent middle meatal antrostomy, together with mobilization and elevation of the collapsed orbital contents by firm packing of the affected maxillary antrum through a buccal antrostomy, the pack being removed about three weeks after placement.

Main Outcome Measures: Symptomatic improvement and reduction in the degree of relative enophthalmos, hypoglobus, and upper eyelid sulcus deformity.

Results: Late-onset enophthalmos after orbital decompression was associated with clinical and radiologic features that resemble the idiopathic imploding antrum syndrome. In all patients, the ethmoidal infundibulum was obstructed by prolapsed orbital fat with secondary antral consolidation, and inward bowing of the maxillary walls was present in five of six patients. After antral drainage and packing, there was an improvement in enophthalmos (mean, 2.7mm; range, 0-4mm) and all but one globe returned to within 2mm of exophthalmometry of the contralateral eye. For recurrent enophthalmos in two patients (minor in one patient and marked in the other), later repair of the orbital floor was undertaken through a lower eyelid swinging flap, using porous polythene sheet, with good cosmetic outcome.

Conclusion: Late-onset enophthalmos after bone-removing orbital decompression seems to be the result of obstruction of maxillary antral aeration, with secondary fluid retention and a subatmospheric pressure in the sinus. This iatrogenic condition, associated in most cases with inward collapse of the maxillary walls, provides a guide to a hypothetical mechanism for the idiopathic imploding antrum (silent sinus) syndrome.

Goldberg, R. A., Soroudi, A. E., McCann, J. D., “Treatment of Prominent Eyes With Orbital Rim Onlay Implants – Four Year Experience,” Ophthalmic Plastic and Reconstructive Surgery, Vol. 19, No. 1, January, 2003.

Purpose: Different approaches have been proposed to address the aesthetic or reconstructive challenge associated with relatively prominent eyes. Operations that address the soft tissue alone are prone to failure if the underlying orbital bony relationships are not addressed. Orbital rim advancement can serve as a supplement to orbital decompression in this setting or as an alternative for patients who may not maximally benefit from decompression surgery.

Methods: We report our 4-year experience with porous polyethylene orbital rim onlay grafts used to address relative proptosis in 24 patients.

Results: All patients had some degree of subjective and objective improvement. Proptosis decreased an average of 4.65mm, with a range of 3 to 9mm, based on single-observer Hertel exophthalmometry measurement (5.2mm in those with concomitant decompression). Lagophthalmos was also improved in all patients with preoperative inadequacy in eyelid closure. Interpalpebral fissure size was reduced 1.3mm on average, with a range of 0.5 to 6mm (2mm in those with concomitant decompression). Average follow-up was 41 months, with a range of 7 to 70 months. In 3 cases, we noted postoperative lower eyelid retraction with eyelid adhesion to the implant; possible risk factors for this complication included reoperative cases and simultaneous eyelid reconstruction with hard palate grafts.

Conclusions: The porous polyethylene orbital rim onlay implant offers a relatively simple and effective surgical technique for the treatment of symptomatic relative protosis. It can be used alone or in combination with other techniques including midface lift, lower eyelid retractor recession, and orbital decompression. To be effective, the implant should be placed so that it is flush with or overlapping the orbital rim; lateral displacement negates the effect of the implant in improving the eyelid/globe relationship. Postoperative eyelid retraction with tethering to the implant is a potential risk of the onlay implant, and although it may not be possible to avoid this in all cases, surgeries should be designed to minimize postoperative eyelid retraction.

Jain, A., Rubin, P. A.D., “Evaluation and Management of Post-Traumatic Enophthalmos,” Operative Techniques in Plastic and Reconstructive Surgery, Vol. 8, No. 4: pp 259-266 (2002)

Enophthalmos repair secondary to orbital and mid-facial trauma is a challenging problem. Generally 2 mm of enophthalmos is considered cosmetically unacceptable, but functional deficits may serve as additional indications for surgery. The clinical evaluation of a patient in the posttraumatic period is confounded by edema, which may mask enophthalmos in the acute setting. Fractures resulting in blow-out of greater than 50% of the floor and medial wall often lead to enophthalmos later, however, there are numerous equivocal cases. This inability to accurately predict patients at risk of developing enophthalmos later has led to two different schools of thought: one advocating early surgical intervention and the other favoring more conservative observation for enophthalmos to manifest itself. We have found in our experience that delayed repair of enophthalmos is not only technically feasible but has the added benefit of avoiding orbital surgery in equivocal cases that my not manifest clinically significant enophthalmos at a later time. The decision whether to operate in the immediate posttraumatic period, however, is predicated on numerous additional factors such as the presence or absence of muscle entrapment and/or an orbitozygomatic fracture. If surgery is performed, meticulous attention to detail is needed to avoid potentially devastating complications. Finally, a review of the current surgical techniques and materials for repair of orbital fractures is provided.

Hwang, K., Kita, Y. “Alloplastic Template Fixation of Blow-Out Fracture” The Journal of Craniofacial Surgery, Volume 13, Number 4, pp. 510-512 (July 2002)

Alloplasts are widely used to reconstruct the orbital defect. The alloplastic material, however, is not uncommonly infected, displaced, and extruded, and forms an epithelial pseudocyst around it. To prevent the depressed fractured bone of the orbital floor from dropping down into the maxillary sinus, an en block fragment of the depressed fracture of the orbital floor was restored after being attached to an alloplastic sheet template which was fixed to the intact orbital floor. This procedure is simple and secure, and intramaxillary packing is not needed to buttress the depressed fractured bone into the sinus.

Holck, D. E.E., DeMartelaere, S., Foster, J. A., Ng, J. D., Blaydon, S., DeBacker, C., “ Porous Polyethylene Spherical Orbital Implants Containing Synthetic Bone Graft Particulate: An Improved Porous Implant” Presented at the ASOPRS 2002 Fall Scientific Symposium, Orlando, Florida U.S.A. (October 19, 2002)

Discussion: While many oculoplastic surgeons have made porous orbital implants their standard implant material in the management of the anophthalmic socket, implant exposure, extrusion, and infection are persistent risks in the early postoperative period. Many postulate that this is due to inadequate fibrovascular ingrowth.

Methods: We previously found that placing synthetic bone graft particulate (Bioglass®, US Biomaterials, Alachua, FL., NovaBone-C/M™, Porex Surgical Inc., Newnan, GA.) in porous polyethylene (PP) orbital implants in a population of New Zealand rabbits offered a significantly more rapid rate of implant vascularization. Several of the authors also have treated successfully porous implant exposures and defects using synthetic bone graft particulate. To evaluate implants of similar size as are used in human patients, we followed vascularization rates (as measured by MRI scanning) of 20mm diameter implants in a population of Yucatan pigs.

Ten adult Yucatan pigs underwent unilateral enucleation with placement of a 20mm PP implant. Five of the implants contained bioactive glass (30% by weight). Each subject underwent biweekly MRI scanning to evaluate vascularization of the implant until complete ingrowth was observed. At four, six, and eight weeks post implantation; PP implants containing synthetic bone graft particulate demonstrated a greater degree of vascularization, on average, by MRI scanning.

Results: Since 510(k) clearance by the FDA, we have implanted porous polyethylene spherical orbital implants in three patients. MRI scanning demonstrated complete vascularization in all three patients prior to six months postoperatively.

Conclusions: Synthetic bone graft particulate may offer advantages to porous orbital implants in promoting more rapid vascularization.

Tawfik, H. A., Dutton, J. J., "Primary Peg Placement In Evisceration With The Porous Polyethylene Orbital Implant," presented at the ASOPRS 2002 Fall Scientific Symposium, Orlando, Florida U.S.A. (October 19, 2002)

Discussion: Good prosthetic motility requires coupling of the implant to the prosthesis. Because porous orbital implants offer the versatility of placing a peg, a wider range of movement can be attained with their use. Pegging typically is performed several months after removal of the eye, when central implant vascularization is documented by magnetic resonance imaging. This entails a second surgical procedure. Furthermore, complications associated with secondary pegging have gradually emerged in recent literature.

Methods: To avoid a second surgery and its attendant complications, Peter Rubin and associates advocated primary placement of the motility coupling (MCP) after enucleation with porous polyethylene conical orbital implant and reported no complications. After enucleation with the standard spherical MEDPOR Implant, the implant may theoretically float in the orbital fat in which it is bathed, and thus is prone to postoperative rotation which may be difficult to prove except when the anterior surface of the implant has been modified or when a peg has been placed.

Results: In order to circumvent such a possibility, eleven patients underwent evisceration with the porous polyethylene spherical implant with primary placement of the motility coupling post during the past 20 months. Patients were followed up for a mean period of 10 months (range, 3-15 months). Spontaneous exposure of the MCP was noted in all patients, and no evidence of implant rotation was seen. At the last follow-up contact with the patients, all had a successful prosthesis fitting with good motility.

Conclusions: In summary, we have observed that primary MCP placement after evisceration with spherical MEDPOR Implants has many advantages including simplifying the process of pegging which might be more challenging if done as a secondary procedure after an evisceration procedure, and combining the enhanced motility effect of evisceration with the wider range of movement made possible by the use of a coupling device. Finally our technique allows the surgeon the use of the more familiar spherical implant without the potential for implant rotation, because the implant and the MCP are firmly secured within the confines of the scleral coating.

Soparkar, C. N.S., Patrinely, J. R., "The MEDPOR® Lower Eyelid Spacer: Follow-Up for Over 200 Cases," presented at the ASOPRS 2002 Fall Scientific Symposium, Orlando, Florida U.S.A. (October 19, 2002)

Discussion: Lower eyelid retraction may develop for a wide variety of reasons. During correction, a semi-rigid internal support is often helpful in certain complicated cases, and we have found the MEDPOR Lower Eyelid Spacer to be more powerful and faster to insert than cartilage or other materials. Yet, success with this implant is highly technique-dependent, and the complication rate is non-trivial, especially during the steep onset of the learning curve. With each complication, however, our technique has evolved, allowing us to tackle cases of increasing complexity. Herein we summarize the complications seen in our first 216 cases, seven of whom were lost to follow-up, yielding a series of 209 implants with an average follow-up of 22 months, range 12-48 months. Among these 209 cases, we experienced 25 complications requiring implant revision or removal.

5

"Winging" – initially our #1 problem, but this has become rare now due to routine use of medial and lateral hang-back suspensory sutures.

5

Exposure/extrusion through the skin – associated with post-surgical trauma; poor eyelid tissue (reconstructed lid that had been irradiated); or over-reaching the technique’s ability. Longest time to implant extrusion was 4 – 5 months. The frequency has been greatly diminished by tucking the implant into a viable, pre-tarsal orbicularis pocket at time of insertion.

6

Ectropion – this is currently our most common, most difficult problem to adjust, although we have learned some implantation principles we believe decrease this occurrence.

1

Entropion – careful implantation technique avoids this problem

2

Over-Correction – eliminated by sitting patients up during surgery.

3

Under-Correction - eliminated by sitting patients up during surgery.

1

Symptomatic Astigmatism – due to too much pressure from implant against a very proptotic globe (stretching the limits of the technique).

2

"Discomfort/Awareness" – after explantation, one of three patients requested re-implantation of the spacer 2 months later

0

Infection

0

Chronic Inflammation

0

Exposure/extrusion through the conjunctiva

Results: During the development of our current implantation technique, we experienced a nearly 12% complication rate. Although insertion of these implants can be rapidly performed, meticulous attention to certain principles is necessary to diminish these problems.

Villarreal, P.M., Monje, F., Morillo, A. J., Junquera, L. M., Gonzalez, C., Barbon, J. J., "Porous Polyethylene Implants in Orbital Floor Reconstruction," Plastic and Reconstructive Surgery, Vol.109, No. 3, pp 877-887 (March 2002)

Purpose: The purpose of this article is to present the authors’ experience with the use of porous polyethylene ultrathin sheets for orbital floor reconstruction.

Methods: Thirty-two patients with orbital floor fractures were treated with porous polyethylene ultrathin sheets. Sixteen cases corresponded to orbitozygomatic fractures, 11 cases corresponded to pure orbital floor fractures, and five corresponded to panfacial fractures. The subciliary approach was used in 15 patients and the transconjunctival approach in nine; another three patients were operated on through a preexisting eyebrow wound, two were operated on with a subtarsal approach, two were operated on through an eyebrow extension of a facial wound, and one patient was operated on through the facial wound.

Conclusions: Orbital floor reconstruction with porous polyethylene sheets is a very reliable method, with good long-term success obtained from several investigators in a diversity of applications and circumstances. Technically, it is easy to work, strong yet somewhat flexible, and carries the possibility for obtaining a precise three-dimensional orbital reconstruction. Its large, open-pore structure allows for rapid vascular, soft-tissue, and bones ingrowth that serves to stabilize the implant in relation to the surrounding tissue.

Kaltreider, S. A., Lucarelli, M. J., "A Simple Algorithm for Selection of Implant Size for Enucleation and Evisceration," Ophthalmic Plastic and Reconstructive Surgery, Vol.18, No.5, pp 336-341 (2002)

Purpose: This prospective study tested a simple formula for selecting an implant size for patients undergoing enucleation, evisceration, and secondary implantation. The formula axial length – 2mm = implant diameter (subtract 1 mm from implant diameter for evisceration and for hyperopia) was tested by the outcome measures, superior sulcus deformity, enophthalmos, and volume of the prosthesis.

Methods: Fifty-four patients undergoing primary or secondary implant surgery after enucleation or evisceration received implants based on the above formula. The volume of the eye, volume of the implant, volume of the prosthesis, and the total percent volume replacement were recorded for each patient. Outcome measures considered clinically acceptable were <2 mm enophthalmos and less than grade 1 superior sulcus deformity, which is defined as barely perceptible deepening of the medial superior sulcus.

Results: The average volume replacement was 101%; average prosthetic volume was 2.1 mL; average grade of superior sulcus deformity was 0.6; and average enophthalmos was 1.2 mm.

Conclusions: This formula allows 100% replacement of the volume removed, leaves space for a prosthesis 1.5 to 2.5 mL.and eliminates clinically unacceptable superior sulcus deformity and enophthalmos in 85% of patients. Patients with a history of infection, radiation, buphthalmos, or large orbital fractures (15%) had residual superior sulcus deformity greater than grade 1 and enophthalmos = 2 mm despite 100% volume replacement. Further study will elucidate the histopathologic process responsible for residual superior sulcus deformity and enophthalmos in the latter subgroup of patients.

Yen, M. T., Anderson, R. L., "Capsular Calcification of Alloplastic Orbital Implants," American Journal of Ophthalmology, Vol. 133, pp 289 –290 (2002)

Purpose: To report calcification of the capsule surrounding solid PMMA 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 MEDPOR® quasi-integrated porous polyethylene orbital implant.

Results: During removal of the original solid PMMA 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.

Folkestad, Lena; Granstrom, Gosta, “Decreased Frequency of Diplopia with the Use of MEDPOR® for Orbital Floor Fractures.” Poster presented at the AAO-HNSF Meeting, San Diego, CA. (2002)

Objectives: In our previous study, we found that permanent diplopia was over-represented among patients who’s orbital floor fracture had been restored and supported by the use of an antral packing (balloon catheter/gauze tampon). In 1995, porous polyethylene sheets (MEDPOR®) replaced that technique. The present study aimed at comparing the outcome after this change of surgical technique.

Methods: During one year, all patients (51) with a fracture of the orbital floor (22% pure blow-out fractures) were treated and followed until one year after trauma. Follow-up consisted of establishing clinical status and the presence of symptoms.

Results: Fractures were mainly due to assaults or falls. 39/51 qualified for an orbital exploration. MEDPOR was used for floor defects exceeding 200 mm or herniations. Sequelae after treatment were reported by 78% of all patients: disturbed sensibility (60%); negative effects on physical appearance (45%), and affected vision (26%), e.g. diplopia (9.5%).

Conclusions: In this study, 14 patients had a MEDPOR Implant, one (7%) of whom ended up with a diplopia at extreme gaze one year after surgery. As a comparison, in 1991 eight patients were treated by means of an antral packing, two (25%) of whom developed permanent and disabling diplopia.

Kaltreider, S. A., Lucarelli, M. J., "A Simple Algorithm For Selection Of Implant Size For Enucleation And Evisceration," Ophthalmic Plastic and Reconstructive Surgery, Vol.18, No.5, pp 336-341 (2002)

Results: The average volume replacement was 101%; average prosthetic volume was 2.1 mL; average grade of superior sulcus deformity was 0.6; and average enophthalmos was 1.2 mm.

Li, T., Shen, J., Duffy, D., "Exposure Rates of Wrapped and Unwrapped Orbital Implants Following Enucleation," Ophthalmic Plastic and Reconstructive Surgery, Vol. 17, No.6, pp 431-435 (November 2001)

Purpose: To compare the complication rate of porous polyethylene orbital motility implants with solid acrylic implants following enucleation and identify possible risk factors.

Methods: The authors retrospectively reviewed the charts of a total of 117 consecutive enucleations performed at the University of Illinois at Chicago between March 28, 1994, and May 28, 1999. Data obtained included patient demographics, surgical indications, implant type, attending surgeons, surgical technique, and any reported complications.

Results: Of the 117 identified cases, 29 were eliminated due to insufficient follow-up data. Of the 88 remaining cases, 48 patients received porous implants and 40 received solid acrylic implants. Implant exposure developed in four cases. All exposures occurred in unwrapped porous polyethylene implants (n=2) or porous polyethylene implants wrapped in absorbable material (n=2). All exposures occurred in patients younger than 18 years of age, and 75% occurred early after trauma-associated enucleation surgery.

Conclusions: The exposure rate of porous polyethylene implants in this study (9%) was found to be comparable to published rates for hydroxyapatite implants. There were no exposures of unwrapped solid acrylic sphere. Unwrapped porous implants in pediatric patients or following trauma-related enucleation may represent an increased risk for postoperative implant exposure. Absorbable wrapping of porous implants may carry the same risk for exposure as no wrapping. Porous implants wrapped in durable material appear to be as safe as solid acrylic spheres.

Ng, S.G.J., Madill, S.A., Inkster, C.F., Maloof, A.J., Leatherbarrow, B. "MEDPOR Porous Polyethylene Implants in Orbital Blowout Fracture Repair," Eye Scientific Journal of the Royal College of Ophthalmologists, Volume 15, Part 5, pp 578-582 (October 2001)

Purpose: Various materials are used in orbital blowout fracture repair. We describe a series of patients with orbital blowout fractures that were repaired using porous polyethylene (MEDPOR) Sheets.

Methods: A non-comparative interventional case series is described of 30 blowout fractures of 30 patients aged 7-60 years (median 29 years) who underwent orbital blowout fracture repair with MEDPOR Sheets. The mean follow-up was 19.1 months (minimum 5 months). The indication for surgery in 6 cases was non-resolving diplopia. The remaining 24 cases had surgery for enophthalmos. Ten cases underwent primary or secondary hydroxyapatite orbital implantation at the same time as orbital floor blowout fracture repair. Data were collected on post-operative motility and diplopia, enophthalmos, cosmesis, complications and re-operations.

Results: In no case was diplopia worsened by blowout fracture repair. Where surgery was performed for the correction of enophthalmos, late surgery did not compromise the surgical results. There were no intraoperative complications. The one major complication was a case of recurrent implant infections leading to implant removal. There were 3 minor post-operative complications: 2 cases of post-operative infraorbital anaesthesia and one case of a palpable titanium screw. Re-operations were performed for pre-existent diplopia, lid laxity, socket abnormalities and mid-facial deformities. None of these arose from the blowout fracture repair.

Conclusions: The study suggests that in orbital blowout fracture repair MEDPOR Implants are safe and effective with few complications. Late surgery for enophthalmos is technically more difficult but is not associated with poorer functional or cosmetic results.

Key Words: Blowout fracture, MEDPOR, Orbital Implant, Porous Polyethylene

Wong, J.F., Soparkar, C.N.S., Patrinely, J.R. "Correction Of Lower Eyelid Retraction with High-Density Porous Polyethylene: The MEDPOR® Lower Eyelid Spacer," presented at the Innovative Approaches To the Treatment Of Graves’ Orbitopathy Meeting, Columbia-Presbyterian Medical Center, New York, New York, (September 2001)

Purpose: To describe the use of a new alloplastic implant for the correction of complex lower eyelid retraction.

Methods: A retrospective review of patient charts and photographs was performed to evaluate the efficacy of the first 50 porous polyethylene Lower Eyelid Spacers (LES) used in the correction of complex eyelid retraction.

Results: Fifty LES were implanted in 38 patients. Follow-up ranged from 18 to 32 months. Average number of surgical procedures attempted for eyelid retraction repair prior to referral to our practice and implantation of the LES was 5, range 0 to 16. After LES implantation, all patients had improvement of their lower eyelid retraction. Three LES implants were revised for eyelid contour deformity ("lateral winging") and one for exposure through the anterior eyelid margin. In two cases, full thickness skin grafts were placed directly over the porous implants with good success.

Discussion: Lower Eyelid Spacers (LES) constructed of porous polyethylene provide a rigid, bio-integrated support for eyelids with severe malposition that are recalcitrant to other corrective efforts.

Key Words: Retraction, eyelid spacer, porous polyethylene

Anderson, R. L., Yen, M. J., "Orbital Implant Provides Old-New Alternative to Pegging," Ophthalmology Times, pp16-17 (August 2001), excerpt from article

We have been very impressed with a quasi-integrated porous polyethylene orbital implant (MEDPOR® Quad™-Motility Implant, Porex Surgical Inc., Newnan, GA). In principle, it is similar to the configuration of the Universal implant.

This new quasi-integrated porous polyethylene orbital implant offers many advantages over other available implants. It requires no wrapping material and can be implanted quickly with simple surgical technique. The quasi-integrated configuration obviates the need for secondary placement of a peg or screw and achieves excellent motility in a single-stage surgery.

Construction with porous polyethylene allows for fibrovascular ingrowth, resulting in improved retention of the implant. The four anterior mounds provide a "lock and key" fit with the ocular prosthesis for improved motility. These mounds also partially support the weight of the prosthesis, thereby reducing the amount of weight being supported by the lower eyelid and fornix, which may help to reduce lower eyelid droop.

Use of porous polyethylene as an implant material is also more economical than hydroxyapatite. In our experience, the motility achieved with the quasi-integrated porous polyethylene orbital implant approaches that of a pegged spherical implant and is much better than an unpegged spherical implant.

Goodman, R.L., Holck, D.E., Ng, J.D., Kikkawa, D.O., Piest, K.L., Otto, R., Soparkar, C.N., Patrinely, J.R. "Orbital Reconstruction Using Custom-Made Orbital Alloplastic Porous Polyethylene Implants," presented at The Association for Research in Vision and Ophthalmology Meeting, IVOS, Vol. 42, No. 4, 1851 - B101, March 15 (2001)

Purpose: Porous polyethylene (MEDPOR, Porex Surgical Inc., Newnan, GA USA) has been used as an alloplastic material in oculoplastic and craniofacial surgery since 1985. It has been successfully used as spherical orbital implants, eyelid spacers, and malar, chin, temporalis fossa, nasal, ear, and cranial reconstruction implants. The interconnecting, open pore structure allows complete fibrovascular ingrowth to maximize implant stability and decrease exposure without a significant foreign body response. This is the first report of successful orbital reconstruction using pre-cut hemifacial and custom-made porous polyethylene orbital implants.

Methods: Five cases of significant bony orbital volume expansion following trauma or tumor resection are presented from a review of oculoplastic surgeons using custom-designed and standard orbital-shaped porous polyethylene implants. Each report demonstrates the challenging repair of an orbital wall defect causing malar flattening or globe dystopia.

Results: A porous polyethylene orbital implant was fitted to each patient's particular bony defect. The MEDPORâ Implant was either custom made based on a stereolithographic model of the defect or precut orbital-shaped implants were trimmed intra-operatively to create the desired shape. Follow-up of 7 to 38 months after orbital repair demonstrated significant improvement in each patient's enophthalmos, hypophthalmos, malar flattening or diplopia with acceptable cosmesis. In one case, re-operation 8 months after the initial implantation demonstrated complete vascularization of the implant.

Conclusions: This is the first reported series of successful orbital reconstruction using standard hemifacial as well as custom-made porous polyethylene orbital implants. These implants provide a matrix for fibrovascular ingrowth which maximize stability and may decrease migration.

Yen, M.T., Anderson, R.L., Lucci, L.M., Caruso, R.T. "Initial Experience With A Quasi-Integrated Porous Polyethylene Orbital Implant," presented at The Association for Research in Vision and Ophthalmology Meeting, IVOS, Vol. 42, No. 4, 1844-B94, March 15 (2001)

Purpose: To describe the initial experience with a new quasi-integrated orbital implant made from porous polyethylene that combines the advantages of host tissue incorporation and excellent motility with a single-stage surgery.

Methods: Nineteen consecutive patients undergoing primary or secondary orbital implantation received the quasi-integrated porous polyethylene orbital implant. Several weeks after implantation, a custom fitted prosthetic shell was made to provide a "lock and key" fit with the orbital implant. Post-operative complications and motility of the prosthetic shell were evaluated.

Results: During the 20 month period between December 1998 and August 2000, 19 patients received the implant as a primary orbital implant after either evisceration or enucleation, and 8 patients received the implant as a secondary orbital implant. Follow-up ranged from 3 months to 22 months with an average of 12.3 months. All patients had excellent motility of their prosthetic shell at their final follow-up visit. No cases of implant extrusion or migration were noted. Two patients required deepening of the inferior fornix to accommodate the increased motility of the prosthesis.

Conclusion: The new quasi-integrated porous polyethylene orbital implant provides excellent motility without the need for secondary placement of pegs or screws. It has the advantage of biocompatibility. It can be used after evisceration, enucleation, and as a secondary orbital implant.

Jacono, A.A., Moskowitz, B. "Alloplastic Implants for Orbital Wall Reconstruction," Facial Plastic Surgery, Vol. 16, No. 1, pp 63-68 (2000)

Nonabsorbable alloplastic implants for orbital wall reconstruction have been widely accepted by surgeons because of their ready availability, stability, and biocompatability. Many complications have arisen with this class of implants because the lack of host tissue integration allows for implant migration, implant extrusion, recurrent hemorrhage, and infection. Porous polyethylene implants provide a welcome alternative as they have the unique property of supporting tissue ingrowth in vivo. Their semirigid structure provides structural stability when used around the orbit, and their malleability allows for easy contouring. This paper presents our surgical approach to reconstructing orbital defects with porous polyethylene implants, including orbital floor, and superior, medial, and lateral wall defects, and discusses the advantages/disadvantages of other nonabsorbable alloplasts.

Key Words: Orbital reconstruction; porous polyethylene; Medpor; alloplasts

Jin, H., Shin, S., Choo, M., Choi, Y. "Endonasal Endoscopic Reduction of Blowout Fractures of the Medial Orbital Wall," Journal of Oral Maxillofacial Surgery, Volume 58, pp 847-851(2000)

Purpose: This article describes the endonasal endoscopic reduction (EER) of blowout fractures (BOFs) of the medial orbital walls and reports the clinical results.

Patients and Methods: Sixteen patients who underwent EER for a BOF of the medial orbital wall were analyzed. The surgical indications for treatment were diplopia, limitation of eye movements, and significant enophthalmos. They were followed-up for at least 3 months after the surgery. Surgical techniques, surgical results, and postoperative complications were reviewed.

Results: There were no significant intraoperative or postoperative complications. Fourteen patients showed complete resolution of symptoms after the surgery. One patient, who had persistent diplopia and remaining enophthalmos, underwent medial wall reconstruction with a MEDPOR surgical Implant (Porex Surgical Inc. College Park, GA) by a transorbital approaoch. Another patient, who had residual enophthalmos, had correction of enophthalmos after insertion of a MEDPOR Implant. Both patients are now symptom-free.

Conclusion: The results indicate that EER is a safe and effective technique for the treatment of BOFs of the medial orbital wall

Patrinely J.R., Soparker, C.N.S. "Lower Eyelid Retraction After Blepharoplasty," presented at the European Society of Ophthalmic Plastic and Reconstructive Surgery 18th Meeting, Paris, France (September 14 -16, 2000)

Lower Eyelid retraction is an increasingly common problem that is rarely fully addressed in texts or the literature. For patients with moderate to severe lamella shortage or middle lamella contraction, many advocate posterior grafts of hard palate, donor sclera, or AlloDerm7 with or without a skin graft. These techniques depend upon creating a rigid middle lamella scar, a process that sometimes is poorly controlled and can add to the eyelid retraction.

In a review of our experience over the past four years, we found nearly 175 patients that required internal eyelid support for retraction repair. In descending order of referral frequency, the most common causes were: (1) over-zealous blepharoplasty, (2) complication of orbital fracture repair, (3) thyroid ophthalmopathy, (4) post-cancer resection, (5) excessive laser resurfacing, (6) eyelid trauma.

Until 18 months ago, we advocated placement of a sub-tarsal cartilage graft (either autologous or cadaveric). Although highly effective, the cartilage required a separate harvest site or use of donor material, was tedious to carve to an appropriate shape, and could not support an overlying skin graft.

For the past 2 years, we have been using a custom 0.4mm thick porous polyethylene implant. This material is easily inserted, quickly biointegrated, and able to support an overlying skin graft. In 83 custom cut implants, we had 3 exposures (none through the conjunctiva) requiring implant removal. With technique modification, we have eliminated this problem. Furthermore, a new pre-fabricated polyethylene eyelid implant is now available that has four built-in essential curves, allowing for less tissue stress, invisible exterior contour, and very rapid insertion. Specific implantation techniques will be reviewed.

In summary, lower eyelid retraction is an increasing problem, in part due to the growing number of clinicians from multiple disciplines who are performing lower eyelid blepharoplasty. In selected cases, placement of a rigid internal eyelid stent (either hand-carved cartilage or preformed porous polyethylene) often obviates or minimizes the need for skin grafting.

Bibliography

McCord CD. "The Correction Of Lower Lid Malposition Following Lower Lid Blepharoplasty",. Plast Reconst Surg. 1999; 103(3) :1036-9

Morton, A.D., Nelson, C., Ikada, Y., Elner, V.M. "Porous Polyethylene as a Spacer Graft in the Treatment of Lower Eyelid Retraction," Ophthalmic Plastic and Reconstructive Surgery, Vol. 16, No. 2, pp 146-155 (2000)

Purpose: An experimental study was performed to: 1) assess the tolerance and incorporation of porous polyethylene (MEDPOR) in the posterior lamella of the rabbit lower eyelid; 2) analyze the effect of implant thickness on incorporation; 3) investigate the ability of conjunctiva to grow over vascularized MEDPOR and; 4) determine the effects of MEDPOR surface modification on biocompatibility and fibrovascularization.

Methods: In Phase 1, 10 rabbit eyelids were operated on to analyze the effects of implant thickness and to develop the surgical technique used in phase II of the study. In phase II, 20 lower eyelids of 10 rabbits received 0.85-mm thick MEDPOR grafts, each rabbit receiving both an uncoated implant and one coated with an immobilized collagen.

Results: There were no extrusions in phase II. With a postoperative follow-up from 14 to 17 weeks. Fourteen of 20 eyelids had full-thickness conjunctival incisions or excisions placed over the MEDPOR implant to determine the growth potential of conjunctiva over a vascularized implant. All but one eyelid showed complete defect coverage, occurring in as little as 3 days. Histopathology indicated complete MEDPOR fibrovascularization as early as 4 weeks after implantation. Because neither coated nor uncoated implants extruded in phase II, no conclusions can be drawn regarding the efficacy of MEDPOR surface modification.

Conclusion: MEDPOR was well tolerated in this soft tissue application, and it offers advantages over other graft materials.

Levine, M.R. "How to Manage Orbital Fractures," Review of Ophthalmology, Vol. VII, No. 3 (March, 2000)

Author discussed cases and types of orbital fractures, symptoms, diagnosis, treatment, surgical strategies and post-operative care. Augograft and allograft material alternatives are mentioned including the use of MEDPORâ Implants.

Duffy, Mark. "Porous Polyethylene Expands Orbitofacial Options," Opthalmology Times, April 1, 2000 Oculoplastic Special Report.

Rubin, P.A.D., Rumelt, S. "Functional Indications for Enophthalmos Repair," Ophthalmic Plastic and Reconstructive Surgery, Vol. 15, No. 4, pp 284-292 (1999)

Purpose: In general, orbital augmentation to correct enophthalmos is pursued to prevent or address an aesthetic deformity. In some cases, however, functional deficits may accompany enophthalmos and may serve as an indication for surgical intervention. The authors describe a series of patients with such deficits.

Methods: A retrospective review at a tertiary health care center of all patients with enophthalmos was conducted to identify a subset of cases in which the enophthalmos was associated with nonaesthetic, functional deficits that could not be attributed to muscular or neural dysfunction, or soft tissue scarring.

Results: Six patients with either traumatic enophthalmos (orbital fractures) or non-traumatic enophthalmos (sinus disease and orbital soft tissue atrophy) demonstrated nonaesthetic ocular dysfunction, including gaze-evoked diplopia, eyelid retraction, lagophthalmos and exposure keratitis. The symptoms and signs resolved in the three patients who underwent orbital augmentation.

Conclusions: In some patients with enophthalmos and globe ptosis, globe malposition may alter the underlying eyelid mechanics or extraocular muscle alignment, resulting in functional as well as aesthetic problems. In these patients, restoring the native orbital anatomy through orbital augmentation can reverse eyelid malposition, ocular surface exposure and symptomatic diplopia, avoiding the need for eyelid or strabismus surgery.

Weinberg, D.A., Goldberg, R.A., Hoenig, J., Shorr, N., Baylis, H.I. "Management of Relative Proptosis with a Porous Polyethylene Orbital Rim Onlay Implant," Ophthalmic Plastic And Reconstructive Surgery, Vol 15, No. 1, pp 67-73 (1999)

Purpose: The position of the globe relative to the orbital rim plays a significant role in the relationship between the eyelids and the cornea. A prominent globe (relative proptosis) may cause eyelid retraction and exposure keratopathy. Simple horizontal lower eyelid tightening exacerbates eyelid retraction. Optimal correction with an orbital decompression or advancement of the orbital rim entails considerable risk. A technically simpler alternative, placement of an orbital rim only implant, was evaluated.

Surgical Methods: Fourteen patients with sympotomatic relative proptosis underwent placement of a porous polyethylene orbital rim onlay implant. Patients who underwent orbital decompression through a coronal or transeyelid approach had the rim implant inserted through the same incision. The implant was placed subperiosteally and fixated to bone with two titanium lag screws. Placement of an orbital rim implant without orbital decompression, orbital rim exposure was obtained through an inferior transconjunctival approach. Implant usually needs to be sculpted, using scissors, a scalpel, or both, based on the patient's anatomy. Manufactured with a groove to accommodate the infraorbital neurovascular bundle. The rim implant usually was immersed in antibiotic solution before placement, although there is no definitive data proving that doing so decreases the risk of infections.It is easy to pass a needle through the porous polyethylene.

Results: Lower eyelid position, exposure keratopathy and ocular discomfort were improved in all patients. Two patients required minor surgical revisions. All 14 patients experienced subjective and objective improvement.

Discussion: The orbital rim onlay implant may be placed in conjunction with orbital decompression surgery t

Literature Review MEDPOR® Biomaterial and Porex Surgical Products