Acellular porcine intestinal submucosa as fascial graft in an animal model: applications for revision tympanoplasty.

OBJECTIVE: To demonstrate regeneration of muscle fascia appropriate for future harvest with the use of acellular porcine intestinal submucosa in a rat model. STUDY DESIGN: Animal cohort study. SETTING: Tertiary care academic medical center. SUBJECTS AND METHODS: Sixteen male Sprague-Dawley rats underwent excision of rectus abdominis muscle fascia. A sheet of acellular porcine intestinal submucosa was placed in the fascia harvest defect. Graft and underlying muscle were harvested at three-, six-, and nine-week intervals. Histologic examination, including immunohistology for anti-von Willebrand factor, was performed at each timepoint. Additional selected specimens were subjected to latex vascular perfusion casts to examine vessel growth patterns within the graft. RESULTS: Gross examination revealed a new tissue plane, indistinguishable from surrounding native fascia. Histology revealed an initial inflammatory response within the graft. Progressive influx of native tissue was noted over successive timepoints. Via collagen-specific staining, we noted progressive reorganization and maturation of the graft collagen matrix. At the final nine-week time point, a new loose connective tissue plane was reestablished between the graft and underlying muscle. Immunohistochemistry and latex perfusion both demonstrate an initial development of small capillaries that progresses over time to greater organization and arteriole formation. CONCLUSION: Fascia regeneration may be possible with use of an acellular porcine intestinal submucosa graft in an animal model. Future studies may prove beneficial in restoring fascia in humans. Implications for potential advantages in tympanoplasty are discussed.

Idiopathic temporal bone encephaloceles in the obese patient.

OBJECTIVES: Our aims were to introduce temporal bone encephalocele (TBE) to the differential diagnosis of persistent middle ear effusion, cerebrospinal fluid otorrhea, or chronic otitis media in obese adults and to demonstrate the basic pathophysiologic principles of morbid obesity as it may lead to the cascade of increased intra-abdominal pressure, increased central venous pressure, benign increased intracranial pressure, and TBE. METHODS: A retrospective review of the medical records was performed to determine the location, nature, and etiology of the encephaloceles identified at our institution from 1989 to 2005. Body mass index was calculated from the patient height and weight data. RESULTS: Eight patients with spontaneous, idiopathic TBE were identified. Body mass index values ranged from 32.0 to 67.5 kg/m(2) with a mean of 48.6 kg/m(2). All patients identified with a spontaneous, idiopathic TBE were obese. CONCLUSION: TBE is associated with morbid obesity in our population and should be considered in the differential diagnosis when evaluating mastoid and middle ear disease in the morbidly obese.