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Biomedical subjects

A F Jahn

Publications and source records attributed to A F Jahn.

12 recordsLinked to original sources
PubMed1992

Experimental applications of porous (coralline) hydroxylapatite in middle ear and mastoid reconstruction.

Hydroxylapatite is a ceramic implant material which has been extensively investigated in the orthopedic and oral surgical literature. A set of animal experiments was carried out to determine the feasibility of the use of porous (coralline) hydroxylapatite for middle ear and mastoid reconstruction. Coralline hydroxylapatite was placed in the mastoid bulla of dogs and was carved into struts which were placed into the middle ear and against the tympanic membrane. Coralline hydroxylapatite is a highly biocompatible material which showed abundant ingrowth when in contact with host bone. There was also good soft-tissue ingrowth and fibrous tissue fixation within the middle ear and against the tympanic membrane. Hydroxylapatite is generally accepted to be osteoconductive, but not osteogenic. However, one of the specimens described with chronic inflammatory mucosal changes, shows de novo new bone formation within the pores of the graft. While normally the bone formed in coralline hydroxylapatite is secondary (lamellar), in this specimen primary (woven) bone was found. Porous (coralline) hydroxylapatite appears to be an excellent otologic graft material. It biointegrates with the host, is osteoconductive, and under certain circumstances may be osteogenic.

Animals↗
PubMed1979

Peripheral facial paralysis secondary to metastatic malignant melanoma. A clinicopathologic report.

We report a case of disseminated malignant melanoma in which the initial sign was an isolated peripheral facial palsy on the left side. The cause of the palsy was established five months later, with the appearance of metastatic axillary nodes. The temporal bones demonstrated tumor infiltration within the marrow spaces of the petrous apices bilaterally. The left facial nerve was also extensively involved with melanoma to the level of the geniculate ganglion.

Autopsy↗
PubMed1979

Metastases to the larynx.

Four patients with metastases to the larynx are reported. The pathways of metastatic invasion of the larynx are discussed and illustrated with whole organ laryngeal sections from these cases. Although three of the four cases were clinically silent, all could have been detected on indirect laryngoscopy. The true incidence of laryngeal metastases appears to be much higher than clinically suspected, and indirect laryngoscopy of all patients "at risk" should be considered.

Adult↗
PubMed1979

Metastatic tumors in the temporal bone--a pathophysiologic study.

Nineteen temporal bones were examined from 11 patients who had metastatic temporal bone disease from a distant primary. The salient clinical features were: the high incidence of occult temporal bone involvement (7 of the 10 clinically documented cases), the considerable incidence of melanoma (3 of 10) and the variable correlation between clinical findings and pathologic localization of tumor in the temporal bone. Pathologic examination revealed two distinct modes of tumor spread within the temporal bone: 1) vascularosseous (petrous apex, mastoid, middle ear, external canal); and 2) perineural (nerves in IAC branches, labyrinthine endorgans). Every case was involved by one or both or these routes and no case of CSF-borne metastasis to the perilymphatic space was seen. The external canal was involved extensively in spite of an intact tympanic membrane. Since the presence of symptomatic or occult metastases in the temporal bone affects treatment and prognosis, they must be actively sought by the clinician.

Adenocarcinoma↗
PubMed1978

Oncocytic lesions of the larynx.

Eight cases of laryngeal oncocytic lesions treated at Toronto Western Hospital between 1957 and 1977 are reviewed. The typical clinical course was of a benign lesion with prolonged dysphonia. A smaller number with bulkier lesions developed symptoms of airway obstruction. The lesions were supraglottic and cystic. They were excised either endoscopically or via a laryngofissure. The pathologic features support the concept that the lesion represents a metaplasiahyperplasia, and therefore the term 'oncocytic cyst' is preferred to terms which imply a neoplastic process. Three patients with oncocytic cysts had associated squamous dysplasia of the vocal cord. Pathologically this supports the theory of tissue response to chronic irritation, since all three were heavy smokers. Clincially the finding necessitates longterm follow-up with a view to possible squamous cell carcinoma that may arise on the true cords. Follow-up in this series showed no recurrence of symptoms in six of eight cases, two being lost to follow-up.

Adult↗
PubMed1977

Surgery and histopathology of the stapes in osteogenesis imperfecta tarda.

Fourteen stapedectomies were performed on ten patients with osteogenesis imperfecta tarda. Clinically, the footplates were softer and more tenuously fixed than in otosclerosis and floating footplates seemed more common. Stapes and stapes fragments from all 14 operations were examined microscopically. The histopathology of osteogenesis imperfecta was contrasted to that of otosclerosis. We believe that the greater degree of structural disorganization and greater area occupied by resorption spaces clearly distinguish the new bone formed in osteogenesis imperfecta from otosclerosis.

Adolescent↗
PubMed1976

Histologic processing and examination of a 4,000-year-old human temporal bone.

We believe this is the first report of a mummy temporal bone successfully processed by decalcification and serial sectioning. The condition of the bone required modifications of standard processing technique. Examination of the sections revealed evidence of antemortem otitis media and mastoiditis. The technique described should prove useful in otopathological studies of other paleontological specimens.

Histological Techniques↗
PubMed1976

Foreign body granulomas of the ear.

Foreign body granulomas of the ear are seldom looked for, but probably common occurrences. They may be due to exogenous or endogenous material which became implanted in the course of trauma or treatment in the external or middle ear. They provoke inflammation which may be subclinical, clinical, or masked by concurrent infection. They can aggravate chronic infection, initiate acute local inflammation, or jeopardize surgical success. Histologically, the foreign material is seen lying freely or partially encapsulated within chronic inflammatory tissue, in close proximity to foreign body giant cells. Medical treatment can only succeed when the offending agent is surgically removed.

Acute Disease↗
PubMed1975

Nonlamellar new bone formation in the anterior attic recess.

An area of nonlamellar new bone formation was observed in the anterior epitympanic region of 27 randomly chosen human temporal bones. The donors ranged in age from 9 to 80 years and had no evidence of ear disease or systemic skeletal or metabolic abnormalities. The frequency of this finding suggests that it is a normal feather of the human anterior attic recess.

Adolescent↗
PubMed1975

Bone formation in the normal human otic capsule.

Postmoretem examination of undecaicified temporal bones from five patients treated with tetracycline during adult life for unrelated disease showed the uptake of tetracycline label within the endochondral bone the otic capsule. Adult endochondral bone is histologically woven (nonlamellar) in character, and has been assumed to be metabolically inert in the healthy state. The strong perlvascular labelling seen suggests that new bone is normally deposited in the otic capsule and that this new bone is lamellar in character. Continuous new bone formation in the presence of a constant net volume of bone implies that resorption must also occur normally within the otic capsule.

Bone Development↗
PubMedDate not supplied

Leiomyosarcoma of the cervical trachea. Report of a case with reconstruction using a latissimus dorsi island flap.

A case of leiomyosarcoma of the cervical trachea is described, detailing clinical presentation, pathologic diagnosis and surgical management. The rarity of this tumor in this location accounted for difficulties in clinical diagnosis and pathologic classification. Surgical treatment involved resection of two thirds of the circumference of the infracricoid trachea, with partial resection of the cricoid cartilage and thyroid gland. The defect was reconstructed using bilateral "butterfly" advancement flaps and a latissimus dorsi myocutaneous island flap. The technique and advantages of the latissimus dorsi flap are briefly described.

Adult↗