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Biomedical subjects

R K Osenbach

Publications and source records attributed to R K Osenbach.

17 recordsLinked to original sources
PubMed2001

Neuraxial infusion in patients with chronic intractable cancer and noncancer pain.

Ever since the application in 1980 of morphine for spinal analgesia in patients with refractory cancer pain, spinal infusion therapy has become one of the cornerstones for the management of chronic, medically intractable pain. Initially, spinal infusion therapy was indicated only for patients with cancer pain that could not be adequately controlled with systemic narcotics. However, over the past decade, there has been a significant increase in the number of pumps implanted for the treatment of nonmalignant pain. Indeed, "benign" pain syndromes, particularly failed back surgery syndrome, are the most common indication for intrathecal opiates. As we have gained more experience with this therapy, it has become apparent that even intrathecal opiates, when administered in the long term, can be associated with problems such as tolerance, hyperalgesia, and other side effects. Consequently, long-term efficacy has not been as significant as had been hoped. Because of the difficulties associated with long-term intrathecal opiate therapy, much of the research, both basic and clinical, has focused on developing alternative nonopioid agents to be used either alone or in combination with opiates. Clinical trials have been and continue to be conducted to evaluate drugs such as clonidine, SNX-111, local anesthetics, baclofen, and many other less common agents to determine their efficacy and potential toxicity for intrathecal therapy. This article reviews the agents developed as alternatives to intrathecal opiates.

Analgesics, Non-Narcotic↗
PubMed1996

Isolated extranodal sinus histiocytosis presenting as an intramedullary spinal cord tumor with paraplegia. Case report.

Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) is a nonneoplastic lymphoproliferative disorder that usually presents with massive painless cervical lymphadenopathy accompanied by fever and weight loss. Extranodal involvement occurs in over 40% of patients; however, isolated extranodal disease without lymph node involvement is unusual. Extranodal involvement of the nervous system is unusual and isolated central nervous system disease in the absence of nodal disease is distinctly rare. The author describes the case of a 35-year-old man who presented with paraplegia and an enhancing intramedullary lesion on magnetic resonance imaging that was suggestive of a primary spinal cord tumor. The lesion was completely resected and histologically proved to be consistent with an isolated extranodal case of Rosai-Dorfman disease. Although a number of cases of this entity involving the CNS have been published, the author believes this case represents the first report of intramedullary spinal cord involvement as the initial and only sign of disease.

Adult↗
PubMed1993

Effects of spinal cord ischemia on evoked potential recovery and postischemic regional spinal cord blood flow.

The effects of spinal cord ischemia on spinal cord blood flow (SCBF) and somatosensory (SSEP) and motor (MEP) evoked potentials were investigated in a rabbit model of reversible spinal cord ischemia. Spinal cord ischemia was produced by balloon occlusion of the infrarenal aorta for 30, 60, and 90 min. SCBF, SSEPs, and MEPs were measured before, during, and 1 h after aortic occlusion. Aortic occlusion produced absolute ischemia of the caudal cord followed by hyperemia upon reperfusion. SSEP's and MEP's were obliterated during ischemia but demonstrated gradual albeit incomplete recovery following reperfusion with amplitude recovery inversely proportional to the duration of ischemia. Later peaks were more severely affected by a given period of ischemia than were early waves. In general, SSEP's were more resistant to ischemia than were MEP's although the differences were not significant.

Animals↗
PubMed1992

Diagnosis and management of the Dandy-Walker malformation: 30 years of experience.

Thirty-seven patients with Dandy-Walker malformation were treated between 1959 and 1989. Eighty percent of patients became symptomatic by 3 years of age, with 70% presenting within the 1st year of life. Hydrocephalus was present in 91% of patients at the time of diagnosis. Clinical presentation was most often heralded by symptoms and signs of hydrocephalus with focal neurological findings being a less prominent feature. One third of children demonstrated developmental delay. Associated congenital anomalies were present in 48% of children. Contemporary neuroimaging including computed tomography and magnetic resonance imaging facilitated diagnosis obviating the need for invasive studies such as pneumoencephalography and ventriculography. Patients were initially managed by posterior fossa craniectomy with membrane excision (8), lateral ventricle shunt alone (13), shunting of the cyst alone (4), or combined shunting of the cyst and lateral ventricles (12). Combined shunting proved superior to the other methods, being successful in alleviating hydrocephalus and posterior fossa symptoms in 92% cases. The overall mortality was 24%, the majority occurring before 1970. Of the 28 survivors, 27 (96%) are shunt-dependent, with 19 having a combined shunt system in place. Therefore, we currently favor combined shunting of the cyst and lateral ventricles as the initial procedure for patients with Dandy-Walker malformation.

Adolescent↗
PubMed1992

Intradural extramedullary cysts of the spinal canal: clinical presentation, radiographic diagnosis, and surgical management.

Fourteen patients with intradural extramedullary cysts of the spinal canal are described. Histological classification included 11 arachnoid, 2 epithelial, and 1 ependymal cyst. There were 9 thoracic, 3 cervical, and 2 lumbar cysts. The most common clinical presentation was a slowly progressive myelopathy. Twelve patients (85%) had objective neurological findings at the time of diagnosis. Radiographic diagnosis was made by a combination of myelography, computed tomographic scan with myelography, and magnetic resonance imaging. Complete surgical resection was accomplished for 8 dorsal cysts, and 6 ventral cysts were widely fenestrated into the subarachnoid space. Overall results were considered excellent or good in 9 patients, fair in 3, and poor in 2. There was one recurrence, which required a second operation. We conclude that the majority of intradural spinal cysts can be successfully managed surgically with a favorable clinical outcome.

Adolescent↗
PubMed1992

Pediatric spinal cord and vertebral column injury.

Between January 1, 1970, and December 31, 1988, 179 children (birth to age 16) were treated for spinal cord and/or vertebral column injury by the Neurosurgical Service at the University of Iowa Hospitals and Clinics. Pediatric injuries accounted for 9% of all spinal trauma seen during this period. The mean age was 10.2 years. Sixty-two children were between birth and 8 years of age and 117 were between ages 9 and 16. The cause, distribution, type of injury, and severity of neurological injury varied with age. Neurological outcome was dependent on the severity of the initial neurological injury. Children with complete or severe incomplete myelopathy uniformly remained with severe neurological dysfunction; children with mild to moderate injuries recovered normal or nearly normal neurological function. Surgical versus nonoperative management had no bearing on neurological outcome. Twelve percent of the children with severe spinal cord injuries developed posttraumatic spinal deformity. We conclude that spinal injury patterns differ between preadolescent and older children. Most injuries can be successfully managed with nonoperative therapy. Prognosis is primarily correlated with the severity of the initial neurological insult. Finally, children with severe spinal cord injury must have close, long-term follow-up to monitor the development of posttraumatic spinal deformity.

Accidents, Traffic↗
PubMed1992

Diagnosis and management of brain abscess.

Over the past 20 years, the diagnosis and management of brain abscess has been facilitated by a number of technologic advances that have resulted in a significant reduction in mortality. Despite these advances in technology, however, brain abscess remains a serious disease. In this article the nature, pathogenesis, and diagnosis of brain abscesses are discussed. Issues regarding surgical versus nonsurgical management, optimal surgical therapy, choice and duration of antibiotics, and the use of corticosteroids are examined in terms of their impact on mortality and long-term neurologic sequelae.

Adrenal Cortex Hormones↗
PubMed1990

Response of spinal cord blood flow and motor and sensory evoked potentials to aortic ligation.

To produce spinal cord ischemia in the lamb, ligation of the thoracic aorta was performed for 15, 30, and 45 minutes in three animals each. Spinal cord blood flow and motor and sensory evoked potentials were measured before, during, and after aortic ligation. Ischemia with a blood flow of zero during ligation was encountered in the thoracic and lumbar cords, followed by hyperemia upon release of the ligature. Both somatosensory and motor evoked potentials were obliterated during aortic ligation and gradually recovered following resumption of flow. Motor and sensory evoked potentials behaved similarly to high aortic ligation.

Animals↗
PubMed1990

Diagnosis and management of pyogenic vertebral osteomyelitis in adults.

Management of vertebral osteomyelitis remains controversial regarding optimum duration of antibiotic therapy and the role of surgery. Forty adults with vertebral osteomyelitis were reviewed. Staphylococcus aureus was the most common pathogen isolated. Disk space narrowing with end-plate erosion was the earliest finding, followed by progressive vertebral body destruction. Magnetic resonance imaging proved extremely valuable in detecting spinal cord compression in patients with neurologic deficit. Treatment should include at least 8 weeks of intravenous antibiotics combined with immobilization for pain reduction. Surgical intervention is indicated for all patients with neurologic deficit. Serial erythrocyte sedimentation rates are valuable for following response to therapy. The value of magnetic resonance imaging in diagnosis is emphasized.

Adult↗
PubMed1990

Spinal cord blood flow in response to focal compression.

Anesthetized sheep were subjected to spinal cord compression to 200 mm Hg at T13 by means of a distensible epidural balloon. Eight animals were subjected to compression for 20 min, 10 animals for 40 min, and 12 animals for 80 min. Spinal cord blood flow (SCBF) and spinal evoked potentials (SEPs) from L7 to C7 and vice versa were measured prior to, during, and 1/2, 1 1/2, 2 1/2, and 3 1/2 h following compression. The traumatized zone manifested a hyperemic response subsequent to balloon withdrawal in the 20-min and 40-min groups. In the 80-min group, SCBF returned to baseline. With compression, SEPs were obliterated in all animals and failed to recover after 3 1/2 h following injury, irrespective of the duration of compression. These results show that reperfusion of the cord following a compressive insult is not accompanied with recovery of SEPs.

Acute Disease↗
PubMed1990

Atlanto-axial instability secondary to solitary eosinophilic granuloma of C2 in a 12-year-old girl.

Involvement of the axis by solitary eosinophilic granuloma is rare. We report a 12-year-old girl who presented with a unifocal eosinophilic granuloma of C2 that resulted in a pathologic fracture and atlanto-axial subluxation. She had no other skeletal or systemic manifestations of histiocytosis X. She was successfully treated with posterior spinal fusion and transoral excisional biopsy. Because solitary lesions may mimic malignant tumors, biopsy is advised in atypical cases. The prognosis for solitary eosinophilic granuloma is almost always favorable in terms of symptomatic improvement and restoration of vertebral height.

Atlanto-Axial Joint↗
PubMed1989

Spinal cord injury without radiographic abnormality in children.

Between 1970 and 1988, 35% of children with traumatic myelopathy demonstrated spinal cord injury without radiographic abnormality (SCIWORA). Young children, especially children under 3 years were particularly vulnerable. Mechanisms of injury were age-specific and included flexion, hyperextension and longitudinal traction. Over 80% of injuries involved the cervical cord. Ninety-five percent of all severe injuries occurred in younger children. Neurologic recovery was directly dependent on the degree of initial neurologic injury. Management included dynamic films to exclude obvious fracture or instability, CT or polytomography to exclude occult fracture, and MRI or CT-myelography to exclude surgical lesions. Cervical immobilization is the cornerstone of therapy for prevention of recurrent episodes of SCIWORA.

Adolescent↗
PubMed1989

Giant aneurysm of the distal posterior inferior cerebellar artery in an 11-month-old child presenting with obstructive hydrocephalus.

Intracranial aneurysms are rare in children although several features distinguish them from adult aneurysms including variation in anatomic distribution and an increased incidence of giant and posterior circulation aneurysms. Subarachnoid hemorrhage is the most frequent presentation; however, clinical presentation suggestive of intracranial tumor is not uncommon making accurate diagnosis difficult. Direct clipping is recommended whenever possible although alternative techniques may sometimes be necessary. This report of a giant aneurysm of the distal posterior inferior cerebellar artery in an 11-month-old child illustrates the occasional difficulty in diagnosis and management of these unusual aneurysms.

Arteries↗
PubMed1986

Meningeal neurosarcoidosis mimicking convexity en-plaque meningioma.

A 34-year old man presented with headaches. Computed tomography scanning revealed an enhancing subdural mass extending from the skull base to the convexity, thought to represent an en-plaque meningioma. Pathologic study revealed extraaxial subdural granulomatous inflammation consistent with neurosarcoidosis.

Adult↗
PubMed1986

Ocular bobbing with ruptured giant distal posterior inferior cerebellar artery aneurysm.

A patient presented comatose with an intraventricular hemorrhage of unknown etiology, and manifested the unusual clinical phenomenon of ocular bobbing. Further evaluation revealed a giant aneurysm of the distal posterior inferior cerebellar artery, which was successfully treated surgically. The pathophysiology of ocular bobbing is discussed as well as the association of this unusual sign with a rare aneurysm.

Adult↗