Porous polyethylene as a spacer graft in the treatment of lower eyelid retraction.

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 I, 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.

Recurrent orbital malignant peripheral nerve sheath tumor 18 years after initial resection.

Malignant peripheral sheath tumor (malignant PNS tumor) is a rare, aggressive, and lethal orbital neoplasm that usually arises from sensory branches of the trigeminal nerve in adults. Malignant PNS tumor spreads along nerves to involve the brain, and most patients die within 5 years of clinical diagnosis. The clinical history and examination, imaging studies, surgical procedures, and pathologic specimens of a 23-year-old man with rapid, posttraumatic onset of left orbital proptosis and pain are reported. Biopsy specimens of the tumor were compared with specimens from the same orbit obtained 18 years previously. Histopathology of the left orbital tumor compared with that of an incomplete excision of a tumor 18 years previously in the same orbit revealed both to be malignant PNS tumor. The patient is alive without recurrence 8 months after orbital exenteration and 18 years after initial tumor presentation. This is the youngest age of occurrence and the longest documented survival of a patient with orbital malignant PNS tumor.

Recurrent trichofolliculoma of the upper eyelid margin.

We report a woman who had a recurrent trichofolliculoma on the upper eyelid margin. Only three cases of this benign tumor on the eyelid have been reported, and no recurrence in this location had been noted in the literature. The lesion, present for 6 years, had been excised twice previously (3 and 4 years before), recurred, and had been injected with a steroid preparation 2 years earlier. Lashes, both normal-looking and immature, arose from the center area of this lesion, and telangiectatic vessels were on its surface. Full-thickness wedge resection was used to excise the lesion completely. Complete primary excision of trichofolliculoma is important, and local steroid preparations should not be used.

Lateral extensions of the Müller muscle.

OBJECTIVES: To define the lateral extension of the Müller muscle and to elucidate its involvement in the development and surgical treatment of Graves (thyroid) eye disease. METHODS: Twelve lateral halves of orbits exenterated from patients with medial or posterior orbital neoplasms were fixed, embedded, and step sectioned at 250-microns intervals to produce histological sections. Gross anatomical dissections of human cadaver heads were also used to corroborate the histological findings. RESULTS: Histological analysis revealed that the Müller muscle extended laterally between the orbital and palpebral lobes of the lacrimal gland in all specimens. The smooth muscle fibers were found to interdigitate with lacrimal ducts passing from the orbital to palpebral lobe and to extend close to the ductal orifices at the conjunctival surface. Gross dissections confirmed that the Müller muscle accompanied the levator aponeurosis lateral extension, which is known to pass between the orbital and palpebral lobes of the lacrimal gland. CONCLUSIONS: Our anatomical findings suggest that the Müller muscle may contribute to the temporal flare frequently seen in eyelid retraction associated with thyroid eye disease. They may also explain the difficulty of treating lateral eyelid retraction in thyroid eye disease and indicate the need for new surgical approaches for severe lateral eyelid retraction.