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Biomedical subjects

M G Hasdemir

Publications and source records attributed to M G Hasdemir.

8 recordsLinked to original sources
PubMed2001

Spinal cord stimulation treatment for angina pectoris: more than a placebo?

BACKGROUND: The effects of thoracolumbal spinal cord stimulation (SCS) are confined to restricted microcirculatory areas. This limitation is generally attributed to a predominantly segmental mode of action on the autonomic nervous system. The goal of this study was to determine whether SCS applied close to supraspinal autonomic centers would induce generalized hemodynamic changes that could explain its alleged antianginal properties. METHODS: Invasive hemodynamic tests were performed in 15 anesthetized Göttingen minipigs submitted to iterative cervical SCS of various duration and intensity. RESULTS: Hemodynamic changes exceeding 10% were observed in 59 of 68 SCS sessions (87%). Their extent and time to peak varied with SCS intensity. At 2, 5, and 10 V, significant (t test p < 0.05) peak changes occurred in cardiac output (+34%, +29%, and +28%, respectively), stroke volume (+19%, +16%, +15%), mean pressure (+9%, +27%, +40%), heart rate (+14%, +23%, +14%), systemic (-17%, NS, NS), and pulmonary vascular (25%, NS, NS) resistances. Strikingly, at 2 V, the increase in cardiac output (+34%) was higher than the synchronous rise in rate pressure product (+22%), indicating efficient cardiac work. At 10 V, however, the cardiac work was inefficient (rate pressure product + 53%/cardiac output + 28%). CONCLUSIONS: Low-voltage cervical neuromodulation reduces the postcharge and improves cardiac work efficiency. The resulting reduction in oxygen myocardial demand may account for decreased anginal pain.

Angina Pectoris↗
PubMed2000

Long-term follow-up study of chronic globus pallidus internus stimulation for posttraumatic hemidystonia.

The authors report the first case of chronic globus pallidus internus (GPi) stimulation for treatment of medically intractable hemidystonia for which long-term follow-up data are available. The patient had developed left-sided low-frequency tremor and hemidystonia after a severe head trauma sustained at 15 years of age. He experienced relief of the tremor but not of the hemidystonia after a thalamotomy was performed in the right hemisphere 3 years postinjury. When the patient was 24 years old, the authors performed a magnetic resonance-guided stereotactic implantation of a monopolar electrode in the right-sided posteroventral GPi. Chronic deep brain stimulation resulted in remarkable improvement of dystonia-associated pain, phasic dystonic movements, and dystonic posture, which was accompanied by functional gain. Postoperative improvement was sustained after 4 years of follow up. Chronic GPi stimulation appears to be a valuable treatment option for posttraumatic dystonia.

Adult↗
PubMed1997

Discriminative microcirculatory screening of patients with refractory limb ischaemia for dorsal column stimulation.

OBJECTIVES: (1) To determine the proportion of patients with critical limb ischaemia refractory to invasive treatment that can be successfully treated by dorsal column stimulation (DCS), and (2) to identify potential responders to DCS by a simple test that is sufficiently predictive to limit the need for a prolonged trial stimulation period. PATIENTS AND METHODS: Twenty patients with chronic limb-threatening ischaemia were assessed by a battery of macro- and microcirculatory tests and a DCS trial of 1 week. Favourable response during the trial determined selection for long-term stimulation. RESULTS: During a mean observation period of 14 months, limb salvage rate (LSR) was 63% overall and 83% among patients selected after a favourable trial. Of the tests performed preoperatively, digital subtraction angiography, Doppler assessment, oscillometry, capillaroscopy, foot temperature, and transcutaneous partial pressure of oxygen (tcpO2) in the supine or sitting position did not adequately predict DCS response. The supine-sitting tcpO2 gradient (delta tcpO2) was a good predictor of DCS outcome, with an 88% LSR when delta tcpO2 > 15 Torr, dropping to 12% when delta tcpO2 < or = 15 Torr. CONCLUSIONS: DCS is a rewarding therapeutic option in selected patients with critical limb ischaemia. delta tcpO2 appears to reliably predict response to DCS and may obviate trial stimulation in most cases.

Adult↗
PubMed1995

Stereotactic guided microsurgery of cerebral lesions.

A total of 33 patients presenting with various cerebral lesions were operated on with stereotactic guided craniotomy. In all cases the lesion could be totally removed and only one patient suffered from a recurrent metastasis. The survival time of patients with malignant brain tumors was in the range of the generally reported data. All the six patients with malignant gliomas developed a recurrence, four of them have since died. Three of the four patients with brain metastases died from systemic progression of their disease, and one patient died from a recurrence of a centrally located metastasis. A new neurological deficit occurred in only two patients. Despite the often deep or central localization of the lesions, major complications were rare. Stereotactic guidance and preoperative selection of the entry point allow a safer surgical procedure, a larger indication for open surgery in cases considered as not removable, and reduce surgical morbidity.

Adult↗
PubMed1993

[Stereotactically-guided microsurgery in cerebral processes].

Stereotaxy-guided microsurgery offers significant advantages in the treatment of deep-seated cerebral lesions, or in lesions that cannot reliably be localized because of their small size or lack of evident landmarks. We report our experience with 16 stereotaxy-guided microsurgical procedures performed with the Leksell or the Lerch stereotactic system. Small superficial lesions were operated on in 6 patients and deep-seated subcortical lesions in 10 patients. The lesion size ranged from 10 to 50 mm and the depth of the lesions varied between 5 and 65 mm. A trans-sulcus approach was chosen in patients with cavernomas and a transcortical or transtumoral one in patients presenting with cerebral tumors. In no patient was a new postoperative neurologic deficit found, i.e. 12 patients had neither a pre- nor a postoperative deficit. 2 patients (with central lesions) of 4 presenting with preoperative deficits showed an impressive recovery, while in the other 2 patients with lesions in the dominant temporal lobe the neurologic deficit remained unchanged. Stereotaxy-guided microsurgery allows safe resection of small or deep-seated cerebral lesions without postoperative morbidity in our series.

Adult↗
PubMed1993

CT-guided stereotactic aspiration and treatment of brain abscesses. An experience with 24 cases.

The present study reports our experience with stereotactic puncture, aspiration and drainage of brain abscesses in 24 patients from a series of 34 consecutive cases. In all patients an intracavitary catheter was left in place for external drainage and daily irrigation with antibiotics. The patients received pre- and postoperatively triple broad spectrum antibiotic treatment, associated with low dose steroids and anti-epileptic drugs. Follow-up CT scans showed immediate reduction of the abscess size and gradual diameter diminution of the enhancing ring structure until its disappearance. The clinical presentation, risk factors, aetiology, outcome, bacteriological and CT findings were analysed. Mortality in this series was 4%. The majority of patients (96%) had no or minimal disability according to the Glasgow Outcome Scale. Our results confirm the value of this treatment policy and suggest that the stereotactic technique is a simple and safe method with minimal mortality and morbidity in the treatment of the majority of chronic brain abscesses.

Adolescent↗