Biomedical subjects

M D Graham

Publications and source records attributed to M D Graham.

137 records · Page 8Linked to original sources

PubMedDate not supplied

Antidromically evoked facial nerve response.

Facial nerve electrodiagnostic tests that are currently available indirectly assess the severity of injury to the intratemporal facial nerve. Antidromic conduction testing is an alternate approach that, if feasible, could provide direct and immediate assessment of proximal facial nerve function. This possibility was tested in a guinea pig model, in which near-field (intracranial) and far-field (extradural) recording techniques were used to assess antidromically evoked facial nerve activity. Response characteristics, topographical distribution, and lesion effects suggest that the recorded potentials represent antidromic activation of the facial nerve. If response amplitude and/or latency can be correlated with the functional state of the nerve, antidromic testing may provide a useful means of assessing proximal facial nerve function in pathologic states.

Animals↗

PubMedDate not supplied

Eustachian tube lymphatics.

Serous otitis media is the most common cause of hearing impairment. The role of lymphatic obstruction in the pathogeneis of serous otitis media is significant. A method for removeal of the human Eustachian tube specimen and two techniques for identification of Eustachian tube lymphatic capillaries are described. One involves the antemorten intratympanic installation of Berlin blue. The other utilizes electron microscopy. Lymphatic capillaries cannot be reliably differentiated from blood capillaries with the light microscope. With electron microscopy, lymphatic capillaries can be differentiated from blood capillaries by differences in the basement membrane. The lymphatic capillary has gaps in the basement membrane with large nuclei in the wall. A blood capillary has a continuous basement membrane and sometimes red blood cells be be identified in the lumen. Using these methods, Eustachian tube lymphatic capillaries in the human are described for the first time in this report.

Adolescent↗

PubMedDate not supplied

Cholesteatoma surgery: residual and recurrent disease. A review of 1,024 cases.

This is an analysis of 1,024 primary cases of mastoid surgery for cholesteatoma operated upon during a ten-year period at the Otologic Medical Group, Inc. Our philosophy of management of the mastoid in these cases has been as follows: 1) avoid an open mastoid cavity when possible; 2) perform the operation in two stages if necessary; 3) reexplore the mastoid and middle ear for residual cholesteatoma when indicated. One-third of 380 revised cases had residual cholesteatoma, disease left by the surgeon. In 260 cases in which the surgeon felt it unlikely that there was residual disease he found it in 23%. In 4% this residual cholesteatoma was found in the mastoid. The incidence of residual cholesteatoma was higher in children and in planned, as opposed to unplanned, revisions. Residual cholesteatoma was detected in the middle ear more frequently than in the epitympanum, and in the epitympanum more frequently than the mastoid. Indications for, and timing of, the reexploration are discussed. Recurrent cholesteatoma refers to a retraction pocket and must be differentiated from residual cholesteatoma; the causes, prevention and treatment are different. Recurrent cholesteatoma was detected in 5%. The most common complication of the disease was a labyrinthine fistula (10%). Operative facial nerve damage occurred in one case. The most common postoperative complication was graft failure (3%). Intact canal wall tympanoplasty with mastoidectomy should be performed as a two-stage procedure in most cases when used in the treatment of aural cholesteatoma.

Adolescent↗

PubMedDate not supplied

Human tympanic membrane--malleus attachment. Preliminary study.

The relationship between the malleus handle and the tympanic membrane in humans has been studied with primary attention being directed to the fibrous layer of the tympanic membrane and its method of attachment to the malleus. This attachment is most intimate at the level of the umbo and becomes progressively more tenuous as the short process is approached. The long process of the malleus, comprised of a bony core, has a definite sleeve of cartilage surrounding its entire length. This cartilage is surrounded by a perichondrial layer which has previously been termed a periosteum. In the lower third, the fibrous lamina propria appears to split equally and the fibers then blend imperceptively with those of the perichondrial layer surrounding the manubrium. At high levels, the attachment is less intimate, most of the fibers appearing to pass lateral to the malleus handle. The embryologic development of the tympanic membrane-malleus junction has been considered and the anatomical features of this area have been considered in relation to functional requirements.

Ear Ossicles↗

PubMedDate not supplied

Osteomas and exostoses of the external auditory canal. A clinical, histopathologic and scanning electron microscopic study.

Osteomas of the external auditory canal are considered clinically to be discrete, pedunculated bone lesions arising along the tympanosquamous suture. They are benign lesions but often are slowly progressive in size. Exostoses of the external auditory canal are broad-based elevations of bone usually multiple and bilaterally symmetric, involving the tympanic bone. It appears that both clinical and histopathologic evidence is sufficient to justify the impression that these two lesions should be considered separate entities and clinical diagnostic and histopathologic criteria have been suggested for diagnosis of these lesions.

Adolescent↗

PubMedDate not supplied

A scanning electron microscopic study of the normal human stapes.

The structure of the normal human stapes was studied with the scanning electron microscope. Specimens were obtained 48 hours after death from adult human temporal bones free from obvious inflammatory disease. The specimens were fixed, dissected, critical-point dried and coated with gold. In this scanning electron microscopic study an attempt has been made to systematically demonstrate the average scanning electron microscopic features of various areas of the normal human stapes. An emphasis has been placed upon demonstrating as clearly as possible the details previously unclear or unrecognized and duplication of many excellent earlier light and electron microscopic studies has been attempted. The typical appearance of the stapes head, neck, arch, crura and footplate has been presented. It is apparent that there exists a high degree of structural specialization particularly in the stapes arch and footplate area.

Ear Ossicles↗

PubMedDate not supplied

Obliterative fibrotic middle ear disease in systemic vasculitis.

A case of bilateral oliterative fibrotic middle ear disease occurring in a patient suffering from leukocytoclastic angiitis is presented. Following a brief discussion of middle ear involvement in systemic vasculitis the pathologic picture and differential diagnosis are considered. Biopsy of unexplained obliterative fibrotic middle ear tissue is recommended.

Diagnosis, Differential↗

PubMedDate not supplied

The arcuate eminence. Topographic orientation in middle cranial fossa surgery.

The superior semicircular canal (SSC) is an important landmark in the middle cranial fossa approach to the temporal bone. This landmark is frequently located by its topographic association to the arcuate eminence. An anatomic study is reported which examines the relationship of the arcuate eminence to the SSC. Techniques for orientation to the internal auditory canal by the middle cranial fossa approach are reviewed and a technique for localizing the SSC when no arcuate eminence is discernible is presented. 1) In 15% of temporal bone specimens, no arcuate eminence was discernible. 2) Of those specimens with an arcuate eminence, 50% demonstrated that the arcuate eminence was rotated posteriorly from the SSC. 3) Despite displacement of the arcuate eminence, the SSC tended to remain perpendicular to the petrous ridge and 60 degrees from the internal auditory canal. 4) Because of their variable relationship, the arcuate eminence should not be used as a substitute for the SSC in the topographic orientation to the internal auditory canal. 5) A technique for locating the SSC when the arcuate eminence is indiscernible is presented.

Adult↗

PubMedDate not supplied

The annular ligament attachment to the normal human stapes footplate. A scanning electron microscopic study.

Following disarticulation of the stapes from the oval window, the free edge of the adult human stapes was examined with the scanning electron microscope. Regions of the articulating surface of the rim were examined and found to vary considerably. Anterior, posterior, and lateral ligaments are described, each with tympanic, intermediate, and lateral components.

Adult↗

PubMedDate not supplied

Morphological evidence of vestibular pathology in long-term experimental diabetes mellitus. I. Microvascular changes.

The influence of long-term experimental diabetes on the microvasculature of the saccule and utricle was investigated using quantitative light and electron microscopic techniques. Basal lamina thickening or reduplication, typically seen in diabetic microangiopathy, were not observed. However, morphometric analysis did reveal a statistically significant increase in capillary diameters along with an increased vascularization of both the saccule and utricle. Both of these microvascular abnormalities may have been caused by the hemodynamic alterations known to occur in diabetes. These alterations include decreased deformability of red blood cells and increased blood viscosity. Either of these factors can lead to a greater stress on the capillary wall and possibly to a reduced oxygen delivery to the tissues.

Analysis of Variance↗

PubMedDate not supplied

Giant cholesterol cysts of the petrous apex: radiologic features.

Four cysts are described that expanded and destroyed the bone of the petrous apex. All patients with these cysts had a sensorineural hearing loss. Mild symptoms referable to cranial nerves VI, VII, IX, X, XI, and XII were seen also. The cysts range in size from 1.5 X 1.5 X 3 cm to 5 X 5 X 6 cm. Grossly and histologically, they were distinct from any lesions seen previously. The lesions were large and contained glistening brown, watery fluid filled with cholesterol crystals. The cyst wall was predominantly fibrous tissue without an epithelium. Minimal chronic inflammatory change and granuloma formation were present within and just outside the cyst wall. These cysts have been described as mastoid cysts, epidermoids, mucoceles, and cholesterol granulomas; until now, they have not been recognized as a single distinct entity. A name emphasizing the pathologic characteristic of the lesion, giant cholesterol cyst, has been suggested. Distinguishing them from other petrous apex lesions preoperatively is difficult, but if the cystic nature of the lesion can be recognized or at least anticipated, more conservative surgery, such as simple drainage versus a more radical procedure, may be possible.

Adult↗