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Biomedical subjects

M Y Oh

Publications and source records attributed to M Y Oh.

7 recordsLinked to original sources
PubMed2001

Spinal cord stimulation for nonspecific limb pain versus neuropathic pain and spontaneous versus evoked pain.

OBJECTIVE: To compare the outcome of spinal cord stimulation (SCS) in patients with nonspecific limb pain versus patients with neuropathic pain syndromes and in patients with spontaneous versus evoked pain. METHODS: A retrospective review of 122 patients accepted for treatment with SCS between January 1990 and December 1998 was conducted. All patients first underwent a trial of SCS with a monopolar epidural electrode. Seventy-four patients had a successful trial and underwent permanent implantation of the monopolar electrode used for the trial (19 patients), or a quadripolar electrode (53 patients), or a Resume quadripolar electrode via laminotomy (2 patients). RESULTS: Of the 74 patients, 60.7% underwent implantation of a permanent device and were followed for an average of 3.9 years (range, 0.3-9 yr). Early failure (within 1 yr) occurred in 20.3% of patients, and late failure (after 1 yr) occurred in 33.8% of patients. Overall, 45.9% of patients were still receiving SCS at latest follow-up. Successful SCS (>50% reduction in pain for 1 yr) occurred in 83.3% of patients with nonspecific leg pain, 89.5% of patients with limb pain associated with root injury, and 73.9% of patients with nerve neuropathic pain. SCS was less effective for the control of allodynia or hyperpathia than for spontaneous pain associated with neuropathic pain syndromes. Third-party involvement did not influence outcome. There was a lesser incidence of surgical revisions when quadripolar leads were used than with monopolar electrodes. CONCLUSION: SCS is as effective for treating nonspecific limb pain as it is for treating neuropathic pain, including limb pain associated with root damage.

Adolescent↗
PubMed2001

Deep brain stimulator electrodes used for lesioning: proof of principle.

OBJECTIVE: Patients with chronically implanted deep brain stimulator (DBS) electrodes can encounter complications requiring hardware removal. We assessed the safety and efficacy of using implanted DBS electrodes to create a therapeutic lesion before their removal. METHODS: Revision or removal of the DBS electrodes was required in two patients who had previously undergone DBS implantation. We conducted a series of in vitro experiments to confirm that the DBS electrodes could be used to generate radiofrequency lesions and to assess the relationship between radiofrequency parameters and lesion size. With this information, and with the approval of the hospital ethical review board, implanted electrodes were used to create incremental radiofrequency lesions in the thalamus in one patient and in the subthalamic nucleus in another. The procedures were performed under local anesthesia with contiguous contacts of the DBS lead connected to the active and reference sites of the RF generator to create a bipolar lesion. RESULTS: A 51-year-old man with essential tremor and a thalamic DBS required repeated battery changes secondary to tolerance and high voltage demands. Rather than replacing the battery, a radiofrequency thalamotomy was performed by using the existing left DBS electrode. At the 6-month follow-up examination, successful lesioning provided near complete tremor control. A second patient, a 50-year-old man with Parkinson's disease who had undergone bilateral subthalamic deep brain stimulation, developed skin erosion over the DBS hardware. A subthalamic nucleus lesion was made through the right DBS electrode. Lesion position and size were confirmed with magnetic resonance imaging. CONCLUSION: Lesions can be made through chronically implanted DBS electrodes in a safe, graded fashion and can produce therapeutic benefit.

Device Removal↗
PubMed2001

CNS cholinergic innervation to the hippocampus in the rat using pseudorabies virus as a neurotracer.

The hippocampus is a central area of the memory-related neural system. Combined immunohistochemistry against choline acetyl transferase and retrograde transneuronal labelling of the pseudorabies virus were used to identify cholinergic neurons in the central nervous system projecting to the hippocampal formation of the rat. Five to ten microL of Bartha strain of pseudorabies virus were injected into the dentate gyrus, CA1 and CA3 of the hippocampus of 20 Sprague Dawley rats using stereotaxic instrument. Forty eight to 96 hr after the injection, the brains were removed and the tissue sections were processed for double immunofluorescence procedure using polyclonal antibodies against pseudorabies virus or choline acetyl transferase. The double labelled neurons were distributed at several different nuclei and the labelling patterns of three different areas of the hippocampus were similar. These data suggests that the cholinergic innervation to the hippocampus were distributed in a transsynaptic manner throughout the whole brain area.

Animals↗
PubMed2000

Dural repair using acellular human dermis: experience with 200 cases: technique assessment.

OBJECTIVE: Many craniotomies require a watertight dural closure. When primary dural repair is not possible, a graft is necessary. Autograft material is not always easily accessible or available, necessitating the use of other material. We performed 200 craniotomies using an acellular human dermal graft (AlloDerm; LifeCell Corp., The Woodlands, TX) to determine its suitability as a dural substitute. METHODS: From June 1996 through March 1998, all patients at Allegheny General Hospital who required a dural substitute graft and in whom autograft harvest was impractical or impossible received the acellular dermal autograft. The running suture technique was used to form a watertight seal. RESULTS: After follow-up for a minimum of 1 year, seven patients have required subsequent surgery. Three patients developed cerebrospinal fluid leaks that were repaired without removing the dermal graft. Four patients developed wound infections that required debridement. In each patient, the graft seemed to be uninvolved in the infectious process and was left in place. The patients were administered antibiotics postoperatively, and there have been no recurrent infections. No adhesion formation or scarring was noted around or underneath the graft in any patient. CONCLUSION: AlloDerm is a reasonable alternative to the available dural graft materials. Its handling characteristics are similar to those of dura, it is biologically inert, and it does not produce adhesion formation.

Biological Dressings↗
PubMed2000

Spinal chronic subdural hematoma.

Although chronic subdural hematomas are rare, they are likely to be more frequently reported as the clinical and magnetic resonance imaging characteristics become defined. Chronic spinal subdural hematomas (CSSDH) are extremely rare; these hematomas are frequently spontaneous and related to minor trauma. Although generally said to carry a poor prognosis, CSSDH can be a reversible cause of paraplegia. This article reviews the history, classification, clinical presentation, and treatment of CSSDH.

Decompression, Surgical↗
PubMedDate not supplied

Haptoglobin polymorphism in Korean patients with cardiovascular diseases.

We investigated the relation between hepatoglobin (Hp) polymorphism and plasma lipid levels in 913 Korean subjects. The distribution of Hp phenotypes did not show any significant differences between the healthy controls and the patients with cardiovascular disease. In the control group, however, the subgroup of > or = 50-year-olds had a significantly higher Hp*1 allele frequency than the subgroup <50 years (p < 0.005). This was not seen in the patient group. Hp phenotypes were associated with levels of high-density lipoprotein cholesterol in the hypertensive group. The results indicate that Hp polymorphism, at least in the Korean population, does not predispose to the occurrence of cardiovascular diseases.

Adult↗