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Biomedical subjects

C M DeBacker

Publications and source records attributed to C M DeBacker.

15 recordsLinked to original sources
PubMed2001

Multiple recurrences in malignant peripheral nerve sheath tumor of the orbit: a case report and a review of the literature.

PURPOSE: To report the onset of malignant peripheral nerve sheath tumor of the orbit 8 years after irradiation in a patient with neurofibromatosis type-1. METHODS: Case report of a young man with neurofibromatosis type-1 who received irradiation for presumed bilateral optic nerve and chiasmal gliomas and in whom a malignant peripheral nerve sheath tumor later developed. Exenteration with extirpation of the entire contents of the orbit was performed 6 times. RESULTS: Complete recurrence of the tumor occurred after each surgical procedure until the patient died of malignancy. CONCLUSIONS: Our case underscores the risk of irradiation, especially in children with neurofibromatosis type-1, and emphasizes that radiotherapy should never be given as an empirical therapy. The authors believe that irradiation and neurofibromatosis type-1 may, in combination, pose a significant risk for the development of malignancies. Clear-cut indications and a precise tissue diagnosis are desirable before the initiation of radiotherapy, particularly in the pediatric population. We recommend that if irradiation is necessary in persons with neurofibromatosis type-1, regular follow-up is imperative. In view of the hostile nature of malignant peripheral nerve sheath tumor, early aggressive treatment appears to be the only viable alternative at present.

Child, Preschool↗
PubMed2000

Anterior tarsal V-wedge resection for cicatricial entropion.

PURPOSE: To determine the effectiveness of using a radiofrequency instrument to resect a V-shaped tarsal wedge for the correction of cicatricial upper eyelid entropion. METHODS: Prospective evaluation of 16 upper eyelids of 11 consecutive patients. RESULTS: The operation was successful in all 16 eyelids, with excellent cosmetic and functional outcomes. CONCLUSIONS: Tarsal V-wedge resection is an effective alternative to other complicated techniques in the management of upper eyelid cicatricial entropion.

Adult↗
PubMed2000

Direct internal eyelash bulb extirpation for trichiasis.

PURPOSE: To evaluate the success of internal eyelash bulb extirpation in the management of trichiasis. METHODS: The procedure was performed on 26 consecutive eyelids. RESULTS: Our technique was successful in all cases, with no recurrence of signs or symptoms. CONCLUSIONS: Internal eyelash bulb extirpation is a safe and effective technique to remove trichiatic lashes, while avoiding injury to the conjunctiva.

Eyelashes↗
PubMed2000

A comparative study of bovine pericardium (periguard) and homologous sclera as lower eyelid spacer graft analogs in New Zealand white rabbits.

PURPOSE: To compare bovine pericardium (Periguard; Bio-Vascular, Inc., St. Paul, MN, U.S.A.) and homologous sclera as spacer graft analogs in a rabbit model. METHODS: A nonrandomized experimental animal study was conducted. Elliptical subconjunctival implants were placed in one lower eyelid each of 10 rabbits. Five rabbits received homologous sclera implants, and five received bovine pericardium implants. The rabbits were killed 7 weeks later, and the lower eyelids were examined clinically and histopathologically. RESULTS: Rabbit eyelids implanted with Periguard had a more marked inflammatory reaction and more significant collagen lamellar disruption than eyelids implanted with homologous sclera, although clinically they appeared quite similar. CONCLUSIONS: Although bovine pericardium elicited a more intense inflammatory response at the histopathologic level, both implants were similarly tolerated at the clinical level. These findings are consistent with animal and human investigations of bovine pericardium in other parts of the body, and warrant further studies into its potential use in the human eyelid.

Animals↗
PubMed2000

Orbital Ewing's sarcoma of the orbit.

PURPOSE: Ewing's tumor is a primary tumor of bone in childhood that only rarely involves the orbit. Most such cases are metastatic from distant sites. This tumor may be confused with other small round cell malignancies of childhood, and immunohistochemical studies are essential in making the diagnosis. METHODS: We present two cases of Ewing's tumor of the orbit. One was in a 22-year-old boy with an occult primary tumor in the frontal bone that became symptomatic after forehead trauma. The other example was in a 7-year-old boy with a known Ewing's primary of the clavicle. The clinical manifestations and diagnostic criteria are discussed. RESULTS: In most cases with orbital involvement, ophthalmic symptoms consist of proptosis, pain, and occasionally visual loss and motility restriction. The diagnosis is typically unsuspected before histologic evaluation. Electron microscopic and immunohistochemical analyses are essential in making the diagnosis and are necessary for all such small round cell tumors. CONCLUSIONS: Ewing's sarcoma is a rare orbital tumor of bone mainly affecting children. Local treatment relying on surgical extirpation and radiotherapy alone has proven inadequate, with 5-year survival rates of <10%. The addition of chemotherapy has improved survival rates significantly to approximately 50%.

Biopsy↗
PubMed1999

Bovine pericardium versus homologous sclera as wrapping materials for hydroxyapatite ocular implants: an animal study.

PURPOSE: We compared bovine pericardium and homologous sclera as wrapping materials for hydroxyapatite (HA) ocular implants in enucleated New Zealand white rabbits. METHODS: Eighteen rabbits were unilaterally enucleated and the sockets implanted with 10-mm HA spherical implants. Six implants were wrapped with homologous sclera, 6 with bovine pericardium, and 6 were not wrapped. The rabbits were killed 7 weeks later and the sockets were examined clinically for inflammation and implant exposure. Exenterated specimens were assessed histopathologically for inflammation and vascularization. RESULTS: No clinical evidence of implant exposure or extrusion was detected in rabbits receiving sclera or bovine pericardium wrapped implants. Histopathologically, the bovine pericardium displayed more inflammation in its outer portion, as well as more disruption of its lamellar arrangement than did the sclera. Fibrovascular in-growth was complete in all wrapped implants. CONCLUSION: Bovine pericardium behaves similar clinically to homologous sclera as a wrapping material for spherical HA ocular implants in a rabbit model, and may represent a reasonable alternative to sclera in such procedures in humans.

Animals↗
PubMed1999

The influence of hyperbaric oxygen therapy and irradiation on hydroxyapatite ocular implant exposure and fibrovascular ingrowth in New Zealand white rabbits.

PURPOSE: Lack of adequate fibrovascular ingrowth has been implicated as a cause of exposure of hydroxyapatite (HA) implants in anophthalmic sockets. We investigated the vasculopathic effects of external beam irradiation, and the fibrovascular-enhancement effects of hyperbaric oxygen (HBO), on HA implant exposure and fibrovascular ingrowth in a rabbit model. METHODS: Eighteen rabbits underwent enucleation with implantation of a 12-mm HA sphere. Six rabbits received 20 Gy of external beam orbital irradiation prior to enucleation. Three irradiated and 6 nonirradiated rabbits received postoperative HBO. Three weeks postoperatively, all rabbits were evaluated clinically for evidence of implant exposure. Implants were then removed, and histopathologic analysis of fibrovascular ingrowth was performed. RESULTS: The amount of vascularization as measured by the depth of ingrowth was greater for nonirradiated (89% ingrowth) than for irradiated (71% ingrowth) animals. HA implant exposure occurred in 1 of 12 (8%) of the nonirradiated, and 4 of 6 (67%) of the irradiated rabbit orbits. HBO did not protect irradiated rabbits from exposure, but did enhance fibrovascular ingrowth in nonirradiated rabbits (100% ingrowth vs. 77% ingrowth). CONCLUSION: Impaired orbital vascularization from prior irradiation appears to retard fibrovascular ingrowth into HA implants, and is associated with an increased incidence of exposure. While HBO did not diminish the likelihood of exposure in irradiated sockets, HA fibrovascular ingrowth in normal orbits appeared to increase with HBO. This may have beneficial clinical application in cases of exposure in nonirradiated orbits.

Animals↗
PubMed1998

Age-related changes in type-I collagen synthesis in human eyelid skin.

PURPOSE: This study was to determine whether age-related decrements in type I collagen synthesis occur in human eyelid skin. METHODS: Using an antibody to procollagen I, we investigated collagen synthetic activity in skin removed for cosmetic purposes from 10 white patients between the ages of 4 and 77 years. Eleven masked referees graded the immunostaining on a scale of 1 (most intense) to 10 (least intense). RESULTS: The multiple range test for rank by group demonstrated more intense staining in younger patients compared with older patients. An average correlation coefficient of 0.8432 (p < 0.05) existed between each of the referee's rankings. CONCLUSION: Type I collagen synthesis diminishes with age in eyelid skin.

Adolescent↗
PubMed1998

Decrease in intraocular pressure after orbital decompression for thyroid orbitopathy.

BACKGROUND: The effect of thyroid orbitopathy on intraocular pressure (IOP) remains controversial. We carried out a study to determine the effect of orbital decompression surgery on the IOP in patients with advanced thyroid orbitopathy. METHODS: The records of 12 consecutive patients (22 eyes) who underwent decompression surgery for severe thyroid orbitopathy between 1985 and 1996 were reviewed. All patients were maintained on essentially the same medications before and after surgery. The IOP readings, obtained by means of applanation tonometry in primary gaze, from the pre- and postoperative visits were recorded, and the net change was calculated. RESULTS: The mean preoperative and postoperative IOP values were 19.8 mm Hg and 16.8 mm Hg respectively, a significant difference (p = 0.008). Seven of eight eyes with an IOP of 21 mm Hg or greater preoperatively had a postoperative IOP less than 21 mm Hg; these eyes showed a mean decrease in IOP of 5.6 mm Hg. The degree of preoperative IOP elevation was found to be a strong predictor of the amount of IOP lowering after surgery (p = 0.014). INTERPRETATION: Our results support the concept that orbital congestion associated with thyroid orbitopathy produces an increase in IOP by elevation of episcleral venous pressure (EVP) and that orbital decompression may reduce the IOP by decreasing EVP. Decompression surgery may obviate the need for more aggressive management of glaucoma in patients with severe thyroid orbitopathy.

Adult↗
PubMed1997

Deviated hydroxyapatite orbital implant syndrome.

PURPOSE: To describe a patient with a deviated orbital implant after enucleation. METHOD: Case report. RESULT: We examined a postenucleation patient with a medially deviated ("esotropic") implant after peg drilling. Modification of the posterior surface of the prosthesis improved cosmesis in the primary position. CONCLUSIONS: During enucleation surgery, surgeons may use a spherical implant rather than modify the anterior face in patients with preexisting strabismus, with severe trauma to the extraocular muscles, or with risk of implant deviation. Additionally, secondary procedures may alter implant position. Occasionally, patients without obvious preoperative risk factors may have deviation of the modified face of the implant. Flattening the implant creates an asymmetric surface that may lead to a deviated orbital implant.

Adult↗
PubMed1996

Solitary fibrous tumor of the orbit.

PURPOSE: We studied a case of solitary fibrous tumor of the orbit in a 75-year-old man. METHODS: The patient had painless, slowly progressive proptosis of eight months' duration. He underwent magnetic resonance imaging, which showed a well-circumscribed retrobulbar mass. The tumor was excised. RESULTS: Examination of the tumor disclosed haphazardly arranged spindle cells alternating with collagenous, hypocellular areas in a richly vascular background without necrosis. Immunoperoxidase stains showed characteristic expression of CD34 and vimentin. CONCLUSION: Solitary fibrous tumor can infrequently involve the orbit and may recur locally and metastasize, necessitating long-term follow-up.

Aged↗
PubMed1996

Differential care of corneal ulcers in the community based on apparent severity.

PURPOSE: To describe current practice patterns in treating infectious keratitis. METHODS: A questionnaire was designed that asked ophthalmologists to describe the diagnostic equipment accessible to their practice for performing smears and obtaining scrapings for microbial culture and sensitivity testing. The questionnaire also presented two hypothetical cases of patients with infectious keratitis. Bacterial keratitis was relatively early and less severe in the first patient, and it was more advanced and more severe in the second patient. Recipients were asked about their diagnostic and therapeutic approach. The survey was mailed to 300 ophthalmologists in Florida, Illinois, and New York. RESULTS: One hundred twenty-four completed surveys (45%) were returned. Six surveys were from cornea specialists, who were excluded from the analysis. Only 18 practices (15%) maintained access to Gram stain supplies, and 58 (50%) maintained culture supplies. Whereas 56% of respondents would treat the patient with the less severe bacterial keratitis without obtaining samples for cultures, only 13% would treat the patient with the more severe condition in this manner (P<0.00001). Of the respondents, 82% would treat the patient with the less severe bacterial keratitis with a fluoroquinolone, compared with 62% for the patient with the more severe infection (P=0.002). The mean frequency of fluoroquinolone administration for the patient with more-severe bacterial keratitis was one drop every 0.88 hours, compared with one drop every 1.48 hours for the patient with the less severe infection. CONCLUSIONS: Ophthalmologists appear to treat suspected infectious keratitis differently, depending on perceived severity; they choose different antibiotic regimens; and are more likely to forgo scrapings for Gram staining and cultures for ulcers that appear less severe. The justification for this approach should be established.

Adult↗
PubMed1996

Effect of neodymium: YAG laser posterior capsulotomy on corneal grafts.

Patients undergoing neodymium: yttrium-aluminum-garnet (Nd: YAG) laser posterior capsulotomy for posterior capsular opacification after penetrating keratoplasty were reviewed retrospectively for incidence of graft rejection. All patients underwent extracapsular cataract extraction with posterior chamber intraocular lens implantation (PC-IOL) performed as a separate or combined procedure. Only one of 20 eyes (4.7%) of 20 patients developed corneal graft rejection over a follow-up period of 6 months to 6 years after capsulotomy. Nd: YAG laser capsulotomy does not appear to increase the risk of corneal graft rejection.

Cataract Extraction↗
PubMed1991

A vesicular preparation enriched in basolateral membranes from cow ciliary body epithelium.

A procedure is described for the preparation of a tissue fraction enriched in basal-lateral membranes of the epithelium of ciliary body dissected from abattoir-derived cow eyes. Microscopical methods established the viability of the epithelial cells in the dissected tissue. A two-step homogenization procedure was employed. First, mild trituration with a Potter-Elvehjem tissue grinder was used to release the epithelial cells with minimal disintegration of the stroma and muscle components. Then, complete vesiculation of the released material was induced with a Dounce homogenizer. This material was fractionated through sequential differential and (Ficoll 400) equilibrium density gradient centrifugation steps. The procedure led to the isolation of a fraction enriched 16.8 +/- 5.5 (+/- SE, n = 5) fold in Na(+)+K(+)-ATPase activity with respect to the initial homogenate. Using a method to artificially generate pH gradients it was demonstrated that the preparation contained sealed vesicles and that the membranes of these vesicles exhibited a K+ selectivity consistent with a plasma membrane origin.

Animals↗