Biomedical subjects
Publications and source records attributed to J F Hahn.
Surgical techniques for treatment of vertigo are updated from the original publication on this subject in 1981. The retrolabyrinthine approach to the cerebellopontine angle for vestibular neurectomy or vascular loop decompression is an important new technique. Preliminary reports are reviewed, and further research is encouraged.
Orbital pseudotumors are inflammatory lesions of the orbit of unknown etiology, which initially mimic an orbital neoplasm. Involvement of the other orbit is uncommon, and extension into the paranasal sinus rare. Intracranial extension of pseudotumor of the orbit is previously unreported. This is a case report of a patient with pseudotumor of the orbit with intracranial extension. The literature of the subject is reviewed.
Thirteen patients with schwannomas of the jugular foramen were operated on at the Cleveland Clinic between 1974 and 1983. The authors' experience in managing these rare tumors is presented. Three major growth patterns of jugular foramen schwannoma were seen, and it is postulated that the position of the tumor depends on its point of origin from the nerves as they pass through the pars nervosa of the jugular foramen. The more distal lesions will expand inferiorly out of the base of the skull, and the more proximal lesions will enlarge into the posterior fossa. Tumors in the mid region will tend to expand primarily into bone. The schwannoma was primarily intracranial in six patients. In five patients the tumor expanded the bone at the base of the skull, with only a small intracranial component, and in two patients the tumor was primarily extracranial, with a small extension into the bone or posterior fossa. The presentation of the patients varied according to the tumor growth pattern. Deafness, vertigo, and ataxia were present in all patients with a major intracranial component, and in most of these there were only minimal deficits of the jugular foramen nerves. By contrast, lower cranial nerve involvement, including hoarseness and weakness of the trapezius and sternocleidomastoid muscles, occurred in patients in whom the tumor was primarily, within the bone or extracranial. Three of the five patients with the major component of the schwannoma within the bone also had deafness. Symptomatic history was longest in those with tumor mainly involving the bone at the base of the skull, and shortest in patients with entirely extracranial tumor. Surgical resection was accomplished with a joint neurosurgical-otological approach, usually combining a posterior fossa exploration with either a translabyrinthine transcochlear or infralabyrinthine procedure. The exact nature of the operation depended upon the presence of intracranial tumor and on the extent of bone or extracranial involvement. Total excision was performed in all cases. There was no operative mortality, and surgery resulted in loss of function of the ninth, 10th, and 11th cranial nerves in most patients. The major postoperative morbidity consisted of swallowing difficulties and sputum aspiration.
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We have used the osmotic pressure technique of Rand, Parsegian and co-workers (Nature 259 (1976) 601-603) to investigate the effect of anion species on the binding of M2+ to dipalmitoylphosphatidylcholine bilayers. Calcium and magnesium salts show a complex behavior which is consistent with both anion binding and screening. We observe virtually no change, within the accuracy of our experiment, in the decay of repulsive pressure with inter-bilayer separation for the acetate and nitrate salts of magnesium and calcium; however, the chloride salt does show a different pressure decay. At any given bilayer separation, 35 A less than dw less than 75 A, with calcium and magnesium salts present, the anions produce a decrease in the repulsive pressure in the order acetate- greater than Cl- greater than NO-3.
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Congenital orbital teratoma is a rare tumor that usually presents with unilateral proptosis in a normal full term infant. These tumors are usually confined to the orbit without extension into the intracranial cavity. A few cases with intracranial extension have been reported. We have developed a combined ophthalmological, otolaryngological and neurosurgical approach to deal with this rare tumor when it extends intracranially.
We reviewed 127 patients who were operated upon for adult presentation Chiari malformation and made six conclusions: (a) The clinical examination remains crucial in the diagnosis. (b) The surgical anatomy is highly varied. (c) Syrinxes can be missed on preoperative contrast studies. (d) By a conservative grading system, we determined that 46% of the patients improved during long term follow-up. One-quarter deteriorated over the long run in spite of any treatment. (e) The overall results did not differ whether the treatment was plugging of the central canal plus decompression or decompression alone. (f) In patients with progression, plugging of the central canal obtained superior results. A review of the literature shows that the natural history of this complex disease process has not been established. This history is needed to identify the course of what may be several important factors that lead to the pathological condition in this disease.
Fifty-seven cases of histologically confirmed cerebral oligodendroglioma treated at the Cleveland Clinic between 1950 and 1980 were reviewed. No difference in the 5-year survival rate was seen in patients treated with postoperative radiation therapy vs. operation alone. These data are compared to previously published series with special emphasis on the role of radiation therapy.
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Since 1960 the most useful and widely employed technique for transphenoidal hypophysectomy has generally been via the sublabial, transeptal approach. This procedure has offered excellent exposure, limited blood loss and a direct, midline approach through the sphenoid to the hypophysis, thus preserving certain midline structures as a guide to the appropriate point of entry into the sella turcica. This approach has certain drawbacks, however, not the least of which is the extensive sublabial incision that must be made and the need to remove or otherwise interfere with the nasal spine. This maneuver can result in changes in the vertical dimension of the septal-collumellar area and, more important, often results in permanent numbness of the upper teeth. In patients who wear dentures, it will sometimes produce a bothersome scar which will require refitting or change in wearing patterns for these dentures. It also requires surgical closure. For the past two years at the Cleveland Clinic Foundation a modified transeptal, transphenoidal approach to hypophysectomy has been undertaken conjointly between the Department of Otolaryngology and Communicative Disorders and the Department of Neurosurgery. This approach to hypophysectomy may offer a good alternative to the sublabial approach, and in competent hands avoids some of the complications of the latter procedure.
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Interference with normal spinal cord functioning is an important, although uncommon, complication of spinal surgery. Spinal evoked potentials have been advocated as a means of monitoring spinal cord transmission during operative procedures. We have developed a simple technique using electrodes inserted into the interspinal ligaments for monitoring purposes. This has produced stable and reproducible recordings with obvious clinical benefit in the first 50 cases in which it has been used.