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Biomedical subjects

G A Meyer

Publications and source records attributed to G A Meyer.

At least 19 recordsLinked to original sources

Increased sacroiliac joint uptake after lumbar fusion and/or laminectomy.

Of 753 adult patients undergoing SPECT and planar bone scintigraphy for the evaluation of low back pain, 43 (6%) showed either unilateral or bilateral increased sacroiliac joint (SIJ) uptake. Five of the 58 abnormal joints were only identified with SPECT (9%), whereas 20 of the 58 abnormal joints were much more convincingly demonstrated by SPECT (34%). Fifteen of the 43 patients with increased SIJ uptake had undergone prior lumbar laminectomy and/or spinal fusion. Such spinal surgery can increase impact loading on the SIJ, leading to mechanical overload and sacroiliitis. Degenerative joint disease, trauma, or other benign pathology accounted for the remaining patients with increased SIJ uptake. The authors conclude that for patients with a history of lumbar spinal fusion and/or laminectomy, increased SIJ uptake usually is caused by altered spinal mechanics rather than malignancy or infection.

Adult

Optic chiasm glioma associated with inappropriate secretion of antidiuretic hormone, cerebral ischemia, nonobstructive hydrocephalus and chronic ascites following ventriculoperitoneal shunting.

An optic chiasm glioma may cause loss of vision, endocrine disturbances, hydrocephalus and cerebral ischemia due to its proximity to the pituitary, hypothalamus, III ventricle and internal carotids. A 3-month-old infant with optic chiasm glioma developed hypopituitarism and inappropriate secretion of antidiuretic hormone with plasma hypo-osmolality. The cerebrospinal fluid (CSF) protein concentration was markedly elevated. The impairment of fluid absorption via arachnoid villi and peritoneum by the high protein content, and reversed osmotic gradient between protein-rich CSF and hypo-osmolar plasma may have contributed to both nonobstructive hydrocephalus and recurrent ascites following ventriculoperitoneal shunting. Cerebral ischemia from carotid compression may have led to cerebral atrophy.

Ascites

Trigeminal nerve neurofibroma: case report.

A case of left trigeminal nerve neurofibroma is presented. The location of the lesion required a multidisciplinary surgical effort for total excision. A vertical ramus osteotomy allowed access to the infratemporal space and base of skull. The frequency and clinical features of trigeminal nerve tumors are discussed.

Bone Plates

Estrogen-receptor protein in intracranial meningiomas.

The increased frequency of meningiomas in women compared with men, and the rapidly progressive course of these tumors in pregnant patients suggest that hormones may be involved in this disease. Tumor tissue from six patients with meningiomas was analyzed for estrogen-receptor protein. Two patients had tumors with very high concentrations of this protein, approaching that found in hormonally sensitive breast carcinoma. The biochemical and possible clinical significance of these findings is discussed.

Adult

Lumbar fusion.

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Humans

A myelographic technique for cysts in the spinal canal and spinal cord.

A collapsing cord in six patients with hydromyelia and a collapsing intraspinal arachnoid cyst in one patient are demonstrated. The authors describe the technique for two-position gas myelography and demonstrate that both intra- and extra-medullary intraspinal processes may collapse during myelography.

Adolescent

A new device for long-term intracranial pressure measurement.

This paper described the authors' approach to the problem of long-term intracranial pressure measurement. Several prior devices have not proven useful for clinical studies of more than a few days duration. Study of 22 of the authors' devices in primates has established the validity of both engineering and medical design assumptions. Useful pressure data has been collected for up to 2 months. Redesign to decrease tambour permeability should allow a useful life of months or years.

Animals

A comparison between anterior and posterior spinal implant systems.

In four patients with intractable pain from metastatic cancer, application of current through electrodes placed on the anterior surface of the cord produced analgesia and pain relief below the level of implant without the development of paresthesias. Application of current through electrodes placed on the dorsal columns in these patients also relieved pain, but to a lesser degree and with the development of associated paresthesias. In one patient, application of current from anterior electrodes to posterior electrodes produced a zone of dissociated sensory loss. While it is simpler to implant electrodes over the dorsal columns, the anterior location may be superior when currents are to be applied for the pain relief in the lower lumbar and sacral dermatomes.

Animals