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Biomedical subjects

U Schick

Publications and source records attributed to U Schick.

At least 19 recordsLinked to original sources
PubMed2002

Microendoscopic lumbar discectomy versus open surgery: an intraoperative EMG study.

This study investigated electromyographic (EMG) activity as a marker of nerve root irritation during two different surgical procedures for lumbar disc herniation. Mechanically elicited EMG activity was recorded during the dynamic stages of surgery in muscle groups innervated by lumbar nerve roots. Confirmation of surgical activity was correlated with the activity of the electromyogram. Fifteen patients with lumbar disc herniations were treated via an endoscopic medial approach, and 15 patients via the open microscopic surgical technique. Results indicated that the endoscopic technique was superior to the open surgical technique and produced less irritation of the nerve root. Significantly less mechanically elicited activity was recorded during both the approach and the root mobilization. The study showed that microendoscopic discectomy allows a smaller incision and less tissue trauma with comparable visualization of the nerve structures than does open surgery.

Adolescent↗
PubMed2002

Technique of microendoscopy in medial lumbar disc herniation.

Various percutaneous techniques to approach the lumbar disc were studied in the past. Chemonucleolysis, laser vaporization, lateral endoscopic foraminal approaches and different techniques of percutaneous nucleotomy remained disappointing due to insufficient root visualization, insufficient decompression or insufficient disc removal. The microendoscopic discectomy is performed via a median approach that allows thorough root exploration, direct evaluation of the compression and determination of contained or non-contained disc material. This is achieved by applying open surgical tools through a tubular retractor under endoscopic visualization. The endoscope is inserted via a sequential set of dilators passed over the initial guide wire. The technique allows a smaller incision and less tissue trauma with comparable visualization of the nerve structures than does standard open surgery.

Decompression, Surgical↗
PubMed2001

Intradural and extradural spinal metastases.

Intradural spinal metastases are uncommon. The outcome of surgical treatment of intra- and extramedullary intradural metastases is considered to be poor, with rapid clinical deterioration. The question of optimal treatment remains controversial. We present an overview of the clinical outcome and surgical treatment of 220 spinal metastases carried out in our centre from 1980 to 1999, with particular emphasis on 11 intradural metastases. Clinical history, signs, surgical approach, outcome, and radiological reports were obtained by review of patient charts. Secondary spinal tumours most often originated from carcinomas of the breast, lung, kidney, gastrointestinal tract, and prostate. In 12% of cases, no primary tumour could be found. Drop metastases of intracranial pathology appeared in 3%. Intradural metastases were seen in 11 patients and formed a very heterogeneous group with predominance of melanoma, lymphoma, and medulloblastoma. Functional recovery and survival time were worse in intradural metastases than in extradural metastases, and the patients were younger. Treatment of metastases is designed to relieve pain and preserve or restore neurological function palliatively. Intradural metastases are a devastating condition with usually fatal outcome. Selected patients who undergo aggressive surgical treatment may have substantially increased survival.

Adult↗
PubMed2001

Recurrence of benign spinal neoplasms.

The outcome of surgical treatment of benign spinal neoplasms is considered to be excellent, with good improvement of neurological function. The risk of recurrence is estimated to be very low, except with subtotal resections. This retrospective study was designed to establish the course of illness, clinical outcome, and recurrence rate of benign spinal tumours. We present an overview of the clinical outcome and surgical treatment of 197 benign spinal tumours carried out in our centre from 1980 to 1999. Clinical history, signs, surgical approach, outcome, and radiological reports were obtained by reviewing patient charts. The most frequent benign tumour was meningeoma (41%), closely followed by neurinoma (33%) and neurofibroma (6.1%). Of all tumours, 79.7% were completely resected. Recurrence happened in 10.2% on an average of 4.3 years postoperatively. Only 2 patients suffered from neurofibromatosis. All neurinomas were completely resected at first operation, whereas three out of seven recurrent meningeomas and all ependymomas were classified as subtotally resected. Seventy per cent were treated by repeated surgical intervention. Benign tumours usually can be completely removed without adding to patients' neurological deficits. Benign tumours recur in 10.2% of cases, thus requiring long-term follow-up. Magnetic resonance imaging (MRI) studies are recommended up to 5 years postoperatively as a routine procedure.

Adult↗
PubMed2001

Pediatric spinal tumors.

We present an overview of the clinical outcome and surgical treatment of 34 pediatric spinal tumors, carried out in our center from 1981 to 1999. Follow-ups were available for 25.5 months on average. Clinical history, signs, surgical approach, outcome and radiological reports were obtained by review of the patients' charts. These pediatric tumors formed a very heterogeneous group, with a predominance of neurinomas and neurofibromas in older children and neuroblastomas or primitive neuroectodermal tumors in younger ones. Ependymomas and astrocytomas were the most frequent intramedullary tumors. Extradural tumors included tumors such as aneurysmal bone cysts, Ewing's sarcoma, histiocytomas, chordomas and an angiofibroma. Following decompression of the spinal cord, the neurological status improved with good functional recovery in 23 children and had deteriorated at follow-up in 5 children. Relapse occurred in 12 cases, including histiocytomas, chordomas, medulloblastoma and tumors associated with genetic disorders. Eighteen children underwent a combined treatment with chemotherapy and/or radiotherapy. The spectrum of pathology is wide and requires multidisciplinary treatment.

Adolescent↗
PubMed2001

Brain abscess.

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Brain Abscess↗
PubMed2000

CT-based needle marking of superficial intracranial lesions for minimal invasive neurosurgery.

A CT-based method of marking superficial intracranial lesions with a needle is presented. This form of neuronavigation can be applied in every neurosurgical centre. Owing to its rapid application it is also suitable for cases of emergency. The neurosurgical approach can be centred precisely over the lesion providing for a minimally invasive operation. The method has proved its efficacy in numerous cases of haematomas and cystic lesions.

Brain Diseases↗
PubMed2000

Brain abscess decades after a penetrating shrapnel injury.

We describe a patient who developed a brain abscess 52 years after sustaining a penetrating craniocerebral shrapnel injury. For 10 years he had suffered from diabetes mellitus, a disorder known to predispose to infections from a diminished body defence. The treatment and aetiology of this rare occurrence is discussed.

Aged↗
PubMed2000

Long term follow up after perimesencephalic subarachnoid haemorrhage.

OBJECTIVES: To evaluate the long term sequelae of perimesencephalic subarachnoid haemorrhage (PMSAH). METHODS: Twenty one consecutive patients were studied. All patients were examined by CT, angiography, MRI, multimodal evoked potentials, and transcranial Doppler sonography. All relevant clinical data during hospital stay and outcome at discharge were obtained by reviewing the charts. Long term follow up was evaluated by reviewing the outpatient files and dedicated outpatient review. Patients were specifically questioned about their perceived recovery, residual complaints, and present occupational status. RESULTS: Apart from the initial CT confirming the diagnosis of PMSAH all other examinations disclosed no abnormalities. None of the patients developed any complications during hospital stay, and all patients were discharged in good clinical condition and without neurological deficits. At long term follow up 62% of the patients had residual complaints consisting of headaches, irritability, depression, forgetfulness, weariness, and diminished endurance. Apart from four patients who had already retired before the PMSAH, only seven of the remaining 17 patients (41%) returned to their previous occupation, whereas nine patients (53%) retired from work and one man became unemployed. One patient had a recurrence of PMSAH 31 months after the first event. CONCLUSION: PMSAH can have considerable long term psychosocial sequelae, and may also recur. Prognosis may not be as good as previously reported.

Adult↗
PubMed1997

Effect of a mechanical vs a pharmacologic increase in aortic pressure on coronary blood flow and thrombolysis induced by IV administration of a thrombolytic agent.

This study was designed to compare the effect of a mechanical vs a pharmacologic increase in BP on coronary artery blood flow and thrombolysis induced by IV administration of recombinant tissue plasminogen activator. We employed a canine model of coronary thrombosis induced by injection of radioactive blood clot in the left anterior descending coronary artery. Subsequently, all dogs underwent phlebotomy to decrease systolic BP to 75 mm Hg and this decreased coronary blood flow by 50%. BP was increased to 130 mm Hg by norepinephrine (NE) infusion or by inflation of a Fogarty catheter placed in the descending aorta. Interventions with NE or with a Fogarty balloon catheter increased coronary artery blood flow to similar values and rates of coronary thrombolysis were similar. However, cardiac output was significantly higher with NE. These results indicate coronary clot lysis is dependent on perfusion pressure and coronary blood flow, not cardiac output.

Animals↗
PubMed1996

Indications for surgery in upper cervical spine injury.

20% of all spine injuries are cervical spine injuries. Surgical treatment of these injuries must take into account the great mobility of this part of the spinal column. Therefore, biomechanical aspects must be considered, especially in the upper cervical spine-C1 and C2. Describing our own therapeutical regimen in 35 patients with unstable upper cervical spine injuries we explain the biomechanical back-ground and review the literature. It becomes evident that ventral approaches are superior to dorsal techniques for decompression, reposition, and stabilization with minimal loss of mobility.

Adolescent↗
PubMed1996

Long-term evaluation of EC-IC bypass patency.

The EC-IC Bypass Study Group could not detect any benefit from surgery compared to medical management in the prevention of stroke in 1985 [15]. During the past years surgical revascularization was re-evaluated and considered as an appropriate treatment for a small subgroup of patients with recurrent focal cerebral ischaemia and impaired haemodynamics. This retrospective study examines the long-term benefit and patency rate of bypass. We present a follow-up of 5.6 years of 47 patients, all of whom underwent bypass surgery after 1985. Forty patients suffered recurring transient ischaemic attacks due to uni- or bilateral internal carotid artery occlusion. Examination included neurologic status, TCD with CO2 or Diamox challenge, angiography, CT and SPECT scans. Neurological improvement was seen in 23% of patients with better results after early surgery, a worsening in 22% suffering further ischaemic events on a postoperative average of 2.8 years. Patency rate for vein graft material was 50%, for the STA-MCA procedure 91%. Occlusion of the vein graft occurred on an average after 1.4 years, other anastomosis after 2.7 years. We conclude that only few patients derived long-term benefit from EC-IC bypasses. Functioning of the bypass worsens over time, suggesting a role for surgery predominantly in the first year of ischaemic events due to insufficient collateral supply. Actual indications for bypass surgery may be patients with failure of maximal medical therapy and progressive ischaemia and haemodynamic compromise.

Adult↗
PubMed1996

Optimizing coronary thrombolysis with i.v. administration of recombinant tissue plasminogen activator. Single bolus vs double bolus vs front-loading.

This study was designed to compare the efficacy of coronary thrombolysis obtained with i.v. administration of three dose regimens of recombinant tissue plasminogen activator (rtPA). Although many studies have confirmed the efficacy of thrombolytic therapy in treatment of acute myocardial infarction, few prospective studies have been designed to determine which dose regimen optimizes the rate of coronary thrombolysis. A canine model was used. Coronary thrombosis was induced by injection of radioactive, autologous blood clots through a catheter placed in the left anterior descending coronary artery. Subsequently, 15 dogs were randomized into 3 groups of 5 dogs each. In group 1 dogs, 1.25 mg/kg of rtPA was administered i.v. as a bolus; in the group 2 dogs, 1.25 mg/kg of rtPA was administered over 60 min. The administration was "front loaded" so that 15% was administered as a bolus, 60% over 30 min, and 25% over 30 min; in group 3, 1.25 mg/kg of rtPA was divided into two i.v. boluses and administered 15 min apart. Coronary thrombolysis was assessed with a gamma camera. Despite differences in rate of administration of rtPA, at 15, 30, and 90 min after onset of treatment, extent of clot lysis was similar between groups. These results indicate that despite differences in dose regimens, rates of thrombolysis are similar when i.v. rtPA is relatively rapidly administered. Further, the similar rates of clot lysis over time between groups suggest both an effective upper limit to the dose-thrombolytic rate relationship and relatively high, sustained steady-state plasma concentrations of rtPA.

Animals↗
PubMed1995

An increase in low aortic pressure increases coronary artery flow and coronary thrombolysis induced by intravenous administration of recombinant tissue plasminogen activator.

PURPOSE: Our study investigated the effects of an increase in aortic pressure, induced by norepinephrine (NE) administration on coronary artery flow in a clotted artery, and rate of coronary thrombolysis induced by intravenous (i.v.) administration of recombinant tissue plasminogen activator (rtPA). METHODS: A canine model of coronary thrombosis, induced by intracoronary injection of radioactive autologous blood clots, was used to test the hypothesis that an increase in aortic blood pressure will increase coronary artery flow and the rate of clot lysis induced by i.v. administration of rtPA. RESULTS: After clot injection, 11 dogs were phlebotomized to decrease systolic aortic pressure to 75 mm Hg. Subsequently, .25 mg/kg of rtPA was administered intravenously over two 15-minute intervals, one during hypotension, and the other after NE infusion had increased systolic blood pressure to 130 mm Hg. In six dogs the hypotensive condition was studied first, and in five dogs the NE-induced normotensive condition was studied first. In all dogs, coronary artery flow and the rate of clot lysis were significantly increased in the normotensive condition. CONCLUSIONS: These results indicate that an increase in a low coronary artery perfusion pressure may enhance coronary artery flow and the rate of thrombolysis.

Animals↗
PubMed1995

Effects of progressive vascular occlusion on slope and intercept of the pulmonary artery pressure-flow relationship.

Pulmonary hemodynamics may be described by mean pulmonary arterial pressure (PAP)-cardiac output (CO) plots. The slope of the PAP-CO relationship may define the incremental resistance (IR), and the extrapolated pressure intercept (P(I)), the effective outflow pressure. The authors investigated the effects of progressive pulmonary vascular occlusion on the IR and P(I) of the PAP-CO plot. Nine experimental and nine time control dogs were studied. In the former group, PAP-CO plots were obtained in three conditions: (1) Baseline, (2) following occlusion of the right pulmonary artery, and (3) following occlusion of the right pulmonary artery and blood flow to the left upper lobe. Following progressive occlusion, there was a corresponding increase in the IR of the PAP-CO plot, from 1.95 to 3.62 to 5.16 mmHg.1-1.min (all P < 0.05). In contrast to the increase in IR, P(I) remained constant. Over the same interval, there were no changes in IR or P(I) in the time control group. These findings indicate that changes in the slope of the PAP-CO plot correspond to changes in the number of parallel vascular units.

Animals↗
PubMed1995

Intravenous administration of recombinant tissue plasminogen activator. Optimizing the rate of coronary thrombolysis.

Although many studies have confirmed the efficacy of thrombolytic therapy in treatment of acute myocardial infarction, few studies have been designed to determine which dose regimen optimizes the rate of coronary thrombolysis. This study was designed to compare the efficacy of coronary thrombolysis obtained with intravenous administration of three dose regimens of recombinant tissue plasminogen activator (rtPA). The same total dose was administered as a bolus, over 30 min, or over 90 min. A canine model was employed. Coronary thrombosis was induced by injection of radioactive blood clot through a catheter placed in the left anterior descending coronary artery. Subsequently, 18 dogs were randomized into 3 groups of 6 dogs each. In group 1 dogs, 0.5 mg/kg of rtPA was administered intravenously as a bolus; in the group 2 dogs, rtPA was administered intravenously over 30 min (rtPA30); in the group 3 dogs, the drug was administered over 90 min (rtPA90). Coronary thrombolysis was assessed with a gamma camera. While at 100 min, the extent of clot lysis was similar between groups, 15 and 30 min after the start of rtPA administration, coronary thrombolysis was significantly less in the rtPA90 group. These results indicate that for a given total dose of rtPA, the rate of intravenous administration may significantly affect the rate of coronary thrombolysis.

Animals↗
PubMed1994

Intraaortic balloon counterpulsation enhances coronary thrombolysis induced by intravenous administration of a thrombolytic agent.

OBJECTIVES: This study was designed to test the hypothesis that in the presence of moderate hypotension, intraaortic balloon counterpulsation would enhance coronary thrombolysis induced by intravenous administration of recombinant tissue-type plasminogen activator (rt-PA). BACKGROUND: Although many studies have confirmed the efficacy of thrombolytic therapy in acute myocardial infarction, few have systematically investigated the effects of alterations in aortic pressure on coronary thrombolysis, and none have previously investigated the effects of intraaortic balloon counterpulsation on thrombolysis. METHODS: The effects of intraaortic balloon counterpulsation on aortic pressure, coronary blood flow and coronary thrombolysis were studied in a canine model. Coronary thrombosis was induced in eight dogs by injection of radioactive blood clot through a catheter placed in the left anterior descending coronary artery. Subsequently, dogs underwent phlebotomy to decrease systolic aortic pressure to approximately 90 mm Hg. After phlebotomy, during a 15-min interval of intravenous administration of rt-PA, coronary thrombolysis and coronary flow were determined during and in the absence of counterpulsation. RESULTS: Intraaortic balloon counterpulsation significantly increased aortic diastolic pressure. Corresponding to the increase in pressure, intraaortic balloon counterpulsation significantly increased the rate of rt-PA-induced coronary thrombolysis. Although not statistically significant, peak diastolic coronary flow tended to increase with counterpulsation. CONCLUSIONS: These results indicate that in the presence of moderate systemic hypotension, intraaortic balloon counterpulsation enhances the rate of rt-PA-induced coronary thrombolysis.

Animals↗