Biomedical subjects
P Dyck
Publications and source records attributed to P Dyck.
Supratentorial arachnoid cysts in adults. A discussion of two cases from a pathophysiologic and surgical perspective.
Large congenital arachnoid cysts are a rare cause of increased intracranial pressure and progressive neurologic deficits in adult life. We describe two patients, diagnosed by computerized axial tomography and surgically treated. The pertinent medical literature was reviewed. The outer cyst membranes were excised, and a communication between cyst and subarachnoid space was established. When possible, the membranes and fluid content of these lesions should be studied. This fluid is best obtained by aspiration prior to dural incision. At present, three etiologic mechanisms of cyst enlargement appear tenable: (1) secretion of fluid by ependymal cells, (2) fluid ingress due to an osmotic gradient, and finally, (3) trapping of fluid by a ball-valve mechanism. Regardless of the reasons why these lesions enlarge, drainage of cyst content into the venous system warrants a clinical consideration.
"Bicycle test" of van Gelderen in diagnosis of intermittent cauda equina compression syndrome. Case report.
The authors describe a simple clinical adjunct to the routine neurological examination of patients with intermittent cauda equina compression syndrome. The "bicycle test" helps exclude intermittent claudication due to vascular insufficiency and frequently confirms the relationship of posture to radicular pain.
Peduncular hemiplegia following removal of large cerebellopontine angle tumors: discussion of a mechanism of brain stem injury.
Large cerebellopontine angle tumors distort and displace the brain stem. Two cases are reported in which ipsilateral hemiparesis ensued postoperatively. Compression of the contralateral cerebral peduncle against the free edge of the tentorium cerebelli appears to be the mechanism leading to this mesencephalic dysfunction. Review of the literature failed to reveal a discussion of this mechanism of brain stem injury. Extension of tumor through the tentorial hiatus appears to make the mesencephalon particularly vulnerable. Incision of the tentorium prior to removal of a tumor when it invades the incisural hiatus may have merit.
Cysticercus cyst of temporal lobe presenting as a tentorial pressure cone.
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The femoral nerve traction test with lumbar disc protrusions.
A easily performed test which can be carried out at the patient's bedside has been described. It is referred to as the femoral nerve traction test. Clinical evidence suggests it may have merit as an aid in the diagnosis of disc herniations that affect the upper lumbar spine.
The stoop-test in lumbar entrapment radiculopathy.
Disabling neurologic symptoms with a paucity of focal signs are frequently encountered in patients who suffer from intermittent cauda equina compression syndromes. The stoop-test has diagnostic merit in these instances. The author's clinical experiences, the test, and its anatomic basis are described.
Spontaneous thrombosis of an arteriovenous malformation.
Extensive thrombosis of a cerebral arteriovenous malformation, not associated with clinically recognizable hemorrhage, appears to be exceedingly rare. Angiographic and operative verification of such an occurrence is described in a 4-year-old child. Computed axial tomographic and ultrasonographic findings are discussed. It is proposed that thrombosis of the anomaly occurred as a result of intravascular turbulence, promoted by progressive elongation and increasing tortuosity of the lesion.
Os odontoideum in children: neurological manifestations and surgical management.
The os odontoideum is a congenital anomaly of the 2nd cervical vertebra. It is an ossicle that is separated from the body of the axis by a variable transverse gap. This weakens atlantoaxial stability. When ligamentous support also fails, subluxation ensues. Compressive myelopathy and vertebral artery obliteration may occur. Eight cases, all in children, were studied prospectively. The neurological manifestations and surgical indications and treatment are discussed.