Michiel Staal - Academia.edu (original) (raw)
Papers by Michiel Staal
Journal of Neurology, Neurosurgery & Psychiatry, 1997
Objectives-To compare clinical eVectiveness and health related quality of life in patients with s... more Objectives-To compare clinical eVectiveness and health related quality of life in patients with severe spasticity who received intrathecal baclofen or a placebo. Methods-In a double blind, randomised, multicentre trial 22 patients were followed up during 13 weeks and subsequently included in a 52 week observational longitudinal study. Patients were those with chronic, disabling spasticity who did not respond to maximum doses of oral baclofen, dantrolene, and tizanidine. After implantation of a programmable pump patients were randomly assigned to placebo or baclofen infusion for 13 weeks. After 13 weeks all patients received baclofen. Clinical eYcacy was assessed by the Ashworth scale, spasm score, and self reported pain, and health related quality of life by the sickness impact profile (SIP) and the Hopkins symptom checklist (HSCL). Results-At three months the scores of the placebo and baclofen group diVered slightly for the spasm score (eVect size=0.20) and substantially for the Ashworth scale (eVect size=1.40) and pain score (eVect size=0.94); health related quality of life showed no significant diVerences. Three months after implantation the baclofen group showed a significant, substantial improvement on the SIP "physical health", "mental health", "mobility", and "sleep and rest" subscales and on the HSCL mental health scale; patients receiving placebo showed no change. After one year of baclofen treatment significant (P<0.05) improvement was found on the SIP dimensions "mobility" and "body care and movement" with moderate eVect sizes. Improvement on the SIP subscale "physical health" (P<0.05; eVect size 0.86), the SIP overall score (without "ambulation"), and the "physical health" and overall scale of the HSCL was also significant, with eVect sizes >0.80. Changes in health related behaviour were noted for "sleep and rest" and "recreation and pastimes" (P<0.01, P<0.05; eVect size 0.95 and 0.63, respectively). Psychosocial behaviour showed no improvement. Conclusions-Intrathecal baclofen delivered by an implanted, programmable pump resulted in improved self reported quality of life as assessed by the SIP, and HSCL physical health dimensions also suggest improvement.
Netherlands heart journal : monthly journal of the Netherlands Society of Cardiology and the Netherlands Heart Foundation, 2013
In this review we discuss the position of electrical neuromodulation as a safe and reversible adj... more In this review we discuss the position of electrical neuromodulation as a safe and reversible adjuvant therapy for treatment of patients with chronic cardiac diseases who have become refractory to conventional strategies. In patients with chronic refractory angina, electrical neuromodulation, independent of the applied modality, has shown to reduce complaints of angina, to enhance exercise capacity, to improve quality of life and to employ anti-ischaemic effects. To date, electrical neuromodulation seems to be one of the best adjuvant therapies for these patients. In addition, neuromodulation in the treatment of heart failure and resistant arrhythmias is the subject of several ongoing studies.
Nederlands tijdschrift voor geneeskunde, Jan 21, 2009
Zeitschrift für Kardiologie, 1997
Patients with therapeutically refractory angina pectoris do not respond to adequate anti-anginal ... more Patients with therapeutically refractory angina pectoris do not respond to adequate anti-anginal medication and are not suitable anymore for revascularisation procedures. This group of patients has a poor quality of life, since their exercise capacity is severely afflicted. A new additional therapy for patients with refractory angina is neurostimulation. The concept of neurostimulation is based on the "gate control theory", a model in which nociceptive unmyelinated fiber afferents (C and A delta) are inhibited by non-nociceptive myelinated fiber afferents. Patients treated with spinal cord stimulation (SCS) show an increase in exercise capacity and a concomitant reduction in myocardial ischemia. A reduction in anginal attacks and nitroglycerin intake is also reported. The mechanisms of action of SCS are unclear, although there is evidence of an increase in myocardial oxygen supply, as is shown in peripheral vascular disease. Sympathetic nervous activity, prostaglandins, an...
Advances and Technical Standards in Neurosurgery, 2007
Ischemic disease (ID) is now an important indication for electrical neuromodulation (NM), particu... more Ischemic disease (ID) is now an important indication for electrical neuromodulation (NM), particularly in chronic pain conditions. NM is defined as a therapeutic modality that aims to restore functions of the nervous system or modulate neural structures involved in the dysfunction of organ systems. One of the NM methods used is chronic electrical stimulation of the spinal cord (spinal cord stimulation: SCS). SCS in ID, as applied to ischemic heart disease (IHD) and peripheral vascular disease (PVD), started in Europe in the 1970s and 1980s, respectively. Patients with ID are eligible for SCS when they experience disabling pain, resulting from ischaemia. This pain should be considered therapeutically refractory to standard treatment intended to decrease metabolic demand or following revascularization procedures. Several studies have demonstrated the beneficial effect of SCS on IHD and PVD by improving the quality of life of this group of severely disabled patients, without adversely influencing mortality and morbidity. SCS used as additional treatment for IHD reduces angina pectoris (AP) in its frequency and intensity, increases exercise capacity, and does not seem to mask the warning signs of a myocardial infarction. Besides the analgesic effect, different studies have demonstrated an anti-ischemic effect, as expressed by different cardiac indices such as exercise duration, ambulatory ECG recording, coronary flow measurements, and PET scans. SCS can be considered as an alternative to open heart bypass grafting (CABG) for patients at high risk from surgical procedures. Moreover, SCS appears to be more efficacious than transcutaneous electrical nerve stimulation (TENS). The SCS implantation technique is relatively simple: implanting an epidural electrode under local anesthesia (supervised by the anesthesist) with the tip at T1, covering the painful area with paraesthesia by external stimulation (pulse width 210, rate 85 Hz), and connecting this electrode to a subcutaneously implanted pulse generator. In PVD the pain may manifest itself at rest or during walking (claudication), disabling the patient severely. Most of the patients suffer from atherosclerotic critical limb ischemia. All patients should be therapeutically refractory (medication and revascularization) to become eligible for SCS. Ulcers on the extremities should be minimal. In PVD the same implantation technique is used as in IHD except that the tip of the electrode is positioned at T10-11. In PVD the majority of the patients show significant reduction in pain and more than half of the patients show improvement of circulatory indices, as shown by Doppler, thermography, and oximetry studies. Limb salvage studies show variable results depending on the stage of the trophic changes. The underlying mechanisms of action of SCS in PVD require further elucidation.
Centrale pijn is pijn die veroorzaakt wordt door een laesie in de hersenen, hersenstam, medulla o... more Centrale pijn is pijn die veroorzaakt wordt door een laesie in de hersenen, hersenstam, medulla oblongata of in het myelum. Centrale pijn kan bestaan uit dysesthesieën, hyperpathie, allodynie en pijn van variabele aard, en is in veel gevallen therapieresistent en invaliderend. Elektrostimulatie van de motorische cortex via een operatief ingebrachte intracraniële, epidurale elektrode kan centrale pijn aan de contralaterale lichaamshelft verminderen. Dit wordt motorcortexstimulatie (MCS) genoemd. Het effect van MCS op centrale pijn berust hoogst waarschijnlijk op suppressie van thalame neuronale hyperactiviteit. Naast behandeling van centrale pijn kan MCS ook leiden tot pijnreductie bij patiënten met aangezichtspijn. Een overzicht van de recente studies naar de effectiviteit van MCS op centrale pijn laat zien dat bij globaal de helft van de patiënten met centrale pijn een goed effect wordt bereikt (>50% reductie van pijn op de VAS-score). Mogelijke bijwerkingen zijn epileptische insulten tijdens plaatsing van de elektrode en gedurende per-/postoperatieve proefstimulatie, bloeding in de operatiewond en het optreden van wondinfecties. Om te bepalen wat de haalbaarheid en klinische effectiviteit van MCS bij centrale pijn in Nederland is, worden patiënten momenteel in 2 neurochirurgische centra behandeld binnen een observationele studie. Indicaties voor MCS zijn centrale pijn of aangezichtspijn met de volgende kenmerken: ernstige pijn (VAS score >5), therapieresistentie, invaliderend karakter van de pijn, en lokalisatie in gelaat, thoraxwand of arm (in geval van centrale pijn). Ter illustratie van deze bijdrage wordt een patiënt uit deze observationele studie besproken. MCS lijkt een redelijke behandelingsoptie te zijn bij patiënten met ernstige, therapieresistente en invaliderende centrale of aangezichtspijn. De meeste studies hebben echter een korte follow-up en bevatten kleine aantallen patiënten. Vaak betreft het redelijk jonge patiënten waardoor het van belang is te onderzoeken wat de effecten en complicaties van MCS na 10 tot 20 jaar zijn. Om die reden én om meer duidelijkheid te krijgen over prognostische factoren en over de effectiviteit van MCS in grotere groepen patiënten lijkt het zinvol MCS-behandelingen vooralsnog alleen in trialverband te laten plaatsvinden.
Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1997
ABSTRACT The objective of this work was to design and use a tremor recording and analysis system ... more ABSTRACT The objective of this work was to design and use a tremor recording and analysis system for stereotactic thalamotomy and thalamus stimulation (DBS). A notebook PC based system was developed. The tremor was measured by accelero-transducers or EMG. The method was used to confirm the definitive localization of the coagulation or stimulation target. Intra-operatively recorded effects of stimulation on the tremor were reproducible. Thermocoagulation and electrode implantation were done only after a significant reduction of the tremor was recorded on thalamic stimulation between 75 and 125 Hz. This method has been used on 9 patients: 2 underwent DBS implantation. It is concluded that intra-operative monitoring of the tremor during ventrolateral thalamotomy or stimulation is useful for identifying the final target for coagulation or electrode implantation
Pediatric Neurosurgery, 1987
Twelve patients of 146 hydrocephalic spina bifida aperta patients, treated with a ventricular dra... more Twelve patients of 146 hydrocephalic spina bifida aperta patients, treated with a ventricular drainage system, died suddenly. In 7 of them the cause of death was most probably related to the use of a ventriculovascular shunt, causing pulmonary embolism. Thromboembolic complications were not seen in the 26 hydrocephalic spina bifida patients treated with a ventriculoperitoneal shunt. In 4 other patients shunt malfunction was considered as the cause of sudden death. The case reports of these 11 patients are presented. Pathophysiological mechanisms are discussed and measures for prevention of these two potentially lethal complications are described.
Neurosurgery, 1994
Proton magnetic resonance spectroscopic imaging (1H-MRSI) and positron emission tomography with t... more Proton magnetic resonance spectroscopic imaging (1H-MRSI) and positron emission tomography with the tracer L-[1-11C]tyrosine (11C-TYR) were used to localize gliomas for biopsy or resection. This is especially helpful in cases of low-grade gliomas, if these lesions are not visualized by contrast-enhanced computed tomographic and magnetic resonance imaging scans. The clues to improved localization are provided by changes in tissue metabolite contents, such as elevation of phosphocholine, indicating cellular proliferation; decrease of N-acetylaspartate, denoting loss of neurons (as these are replaced by tumor cells); and elevation of lactate, pointing to the prevalence of glycolysis, as observed in many tumors. These data on tissue metabolite content have been obtained in vivo in the patient by proton magnetic resonance spectroscopy; metabolite maps derived from these data then visualize the distribution of the various metabolites over the section of the brain under investigation. Alternatively, localization of a tumor may be achieved by means of positron emission tomography depicting the pattern of uptake of the amino acid tracer 11C-TYR, as it tends to be incorporated in the process of cellular proliferation and protein biosynthesis. Five cases are presented as examples.
Neuromodulation: Technology at the Neural Interface, 2011
Patients suffering from chronic angina pectoris, insufficiently controllable with medication an... more Patients suffering from chronic angina pectoris, insufficiently controllable with medication and revascularization, are an increasing medical and psychosocial problem. Although spinal cord stimulation (SCS) is proven to employ, safe, long-term anti-angina, and anti-ischemic effects for these patients, the use of SCS in this group remains limited. The reason for this restricted use is largely unknown. However, among other reasons, it may be related to the difficulties in positioning an electrode in the epidural space. We studied the feasibility and efficacy of subcutaneous implantation of an entire system. Seven male patients, mean age 67 ± 3.6 years, received complete subcutaneously implanted electrical nerve stimulation (SENS) systems, with one or more leads fixed in parallel with the sternum, covering the angina area. At baseline and 2 months follow-up patients performed exercise and quality of life tests (Seattle Angina Questionnaire and diaries number angina attacks and glyceryl trinitrate use). All patients showed clinical relevant improvement (baseline vs. follow-up), in exercise (63%) and quality of life (Seattle Angina Questionnaire 59%). The number of angina attacks dropped 82% and the number of glyceryl trinitrate use decreased by 90%. No major adverse events were observed. This small feasibility study demonstrates SENS to be an effective and safe method to treat patients suffering from refractory angina. Furthermore, SENS is less invasive and appears to have less lead migrations compared with SCS.
The Lancet, 1999
The results of several cohort studies suggest that patients with advanced Parkinson&amp;#... more The results of several cohort studies suggest that patients with advanced Parkinson&amp;#39;s disease would benefit from unilateral pallidotomy. We have assessed the efficacy of unilateral pallidotomy in a randomised, single-blind, multicentre trial. We enrolled 37 patients with advanced Parkinson&amp;#39;s disease who had, despite optimum pharmacological treatment, at least one of the following symptoms: severe response fluctuations, dyskinesias, painful dystonias, or bradykinesia. Patients were randomly assigned to unilateral pallidotomy within 1 month or to pallidotomy after the primary outcome assessment (6 months later). The primary outcome was the difference between the groups in median changes on the motor examination section of the unified Parkinson&amp;#39;s disease rating scale (UPDRS 3) score done in the off phase. Secondary outcome measures included levodopa-induced dyskinesias (dyskinesia rating scale [DRS]) and extent of disability (UPDRS 2). The median UPDRS 3 off score of the pallidotomy patients improved from 47 to 32.5, whereas that of control patients slightly worsened from 52.5 to 56.5 (p&amp;lt;0.001). In the on phase the median DRS score improved 50% in pallidotomy patients compared with no change in controls. The UPDRS 2 off score improved with a median of 7 in the pallidotomy group. Two treated patients had major adverse effects. Unilateral pallidotomy is an effective treatment in patients with advanced Parkinson&amp;#39;s disease, who have an unsatisfactory response to pharmacological treatment.
The success of stereotactic pallidotomy procedures is determined by the accuracy of the target fi... more The success of stereotactic pallidotomy procedures is determined by the accuracy of the target finding procedure. The first step always consist of the assignment of the coordinates of target as an anatomical base where X-ray is used. The second step is the final positioning of the stereo tactical placed electrode where the function of targeted neuronal structures has to be monitored. This is usually done by neurological examination of the patient during the procedure. In this study, an instrument is developed that records the finger and hand movements during performance test for bradykinesia as one of the prominent symptoms of the patient and tremor, which is a minor symptom here. Thirteen patients were examined. All were in the `off-state'. Despite patients usually doing well in the performance test, an improvement, expressed in a frequency, is noticed in both the finger tapping and diadochokinesis tests
Nederlands Tijdschrift Voor Geneeskunde, 2009
Clinical Neurology and Neurosurgery, 1997
British Journal of Anaesthesia, 2013
Editor's key points † There are very few methodologically sound studies exploring sympathetic reg... more Editor's key points † There are very few methodologically sound studies exploring sympathetic regulation of CBF. † This review suggests that sympathetic system plays little role in regulating CBF under normal physiological conditions.
Archives of physical medicine and rehabilitation, 2014
To review all pharmacological and physiological data available on intrathecal baclofen (ITB) ther... more To review all pharmacological and physiological data available on intrathecal baclofen (ITB) therapy and to evaluate its use in clinical practice and future research. PubMed was searched for relevant anatomic, physiological, and pharmacological data available on ITB. All currently available data on ITB pharmacokinetics (PKs) and pharmacodynamics (PDs) in both human and animal studies were reviewed and combined with the anatomy and physiology of the intrathecal space and cerebrospinal fluid flow. Only 4 studies reported PK data on ITB in humans. More studies reported PD data on ITB; however, none were combined with PK data. More detailed data on PK could be gathered from studies using an animal model. ITB does not spread equally over the intrathecal space after injection, but it diffuses according to a concentration gradient. ITB distribution can be influenced by the location of the catheter tip and by changing the infusion mode. The pharmacological and physiological data on ITB can ...
Restorative neurology and neuroscience, 1993
In order to establish the number, the viability and the developmental potential of GABAergic neur... more In order to establish the number, the viability and the developmental potential of GABAergic neurons present in dopaminergic ventral mesencephalic (VM) grafts from embryonic rat, we have studied the survival and development of these neurons in culture. The GABAergic fraction demonstrated a highly disproportionate survival in culture in relation to other VM neurons resulting in a drastic change in the neuronal composition of the dissociated VM grafts. The occurrence of a similar gradual dominance of GABAergic neurons at the site of intracerebral implantation, may affect the development of grafted dopaminergic VM neurons and their interaction with host striatal cells.
Stereotactic and functional neurosurgery, 2007
Long-term evaluation of treatment of chronic, therapeutically refractory tinnitus by means of chr... more Long-term evaluation of treatment of chronic, therapeutically refractory tinnitus by means of chronic electrical stimulation of the vestibulocochlear nerve. Inclusion criteria were severe, chronic, therapeutically refractory, unilateral tinnitus and severe hearing loss at the ipsilateral site. Out of 6 patients, 4 patients were selected for long-term evaluation. Two patients were not evaluated because of premature dropout. A stimulation electrode was placed around the vestibulocochlear nerve through a retrosigmoid approach and connected to a subcutaneously positioned pulse generator via an extension cable. Follow-up was performed 3 months and 42.5 months after implantation. Three measures for treatment outcome were used. First, effect sizes were determined by means of the total Tinnitus Handicap Inventory (THI) score using Cohen's formula. Second, general and tinnitus-specific audiometric tests were performed in on and off conditions of the neurostimulation system. Third, record...
Stereotactic and functional neurosurgery, 1990
This study was carried out as a prelude to possible implantations of cultured human fetal dopamin... more This study was carried out as a prelude to possible implantations of cultured human fetal dopaminergic grafts in parkinsonian patients. Examination of fetal rat ventral mesencephalon tissue for morphology, viability, and dopamine content showed an optimal gestational age for neural grafting in rat experiments of approximately 17 days. Moreover, fetal rat ventral mesencephalon tissue was cultured, and neural dopaminergic cells were observed in cell culture in 4 (11%) out of 36 ventral mesencephalon specimens derived from 15- to 21-day-old rat fetuses. Human fetal donor material from elective abortions was examined for morphology and cell culture possibilities. In 48 curettements, fetal tissue was seen in 34 (71%) of these, resulting in 17 (50%) cultures containing dopaminergic cells. Both fetal rat and human cell cultures were continued for approximately 8 weeks and appeared to remain positive upon immunocytochemical dopamine staining.
Stereotactic and Functional Neurosurgery, 1993
There is increasing interest in the use of human fetal dopaminergic tissue as a source of striata... more There is increasing interest in the use of human fetal dopaminergic tissue as a source of striatal transplant in parkinsonian patients. This tissue is acquired by elective abortions. The possibilities of the use of this tissue were studied by macroscopical examination, cell-culturing followed by immunohistochemical staining and by high performance liquid chromatography. It turned out that 50% of the curettages obtained by suction abortion were too fragmented to reliably recognize the dopamine-containing area (ventral mesencephalon). Furthermore, dissection of the brainstem immediately after the abortion procedure seemed to be of utmost importance.
Journal of Neurology, Neurosurgery & Psychiatry, 1997
Objectives-To compare clinical eVectiveness and health related quality of life in patients with s... more Objectives-To compare clinical eVectiveness and health related quality of life in patients with severe spasticity who received intrathecal baclofen or a placebo. Methods-In a double blind, randomised, multicentre trial 22 patients were followed up during 13 weeks and subsequently included in a 52 week observational longitudinal study. Patients were those with chronic, disabling spasticity who did not respond to maximum doses of oral baclofen, dantrolene, and tizanidine. After implantation of a programmable pump patients were randomly assigned to placebo or baclofen infusion for 13 weeks. After 13 weeks all patients received baclofen. Clinical eYcacy was assessed by the Ashworth scale, spasm score, and self reported pain, and health related quality of life by the sickness impact profile (SIP) and the Hopkins symptom checklist (HSCL). Results-At three months the scores of the placebo and baclofen group diVered slightly for the spasm score (eVect size=0.20) and substantially for the Ashworth scale (eVect size=1.40) and pain score (eVect size=0.94); health related quality of life showed no significant diVerences. Three months after implantation the baclofen group showed a significant, substantial improvement on the SIP "physical health", "mental health", "mobility", and "sleep and rest" subscales and on the HSCL mental health scale; patients receiving placebo showed no change. After one year of baclofen treatment significant (P<0.05) improvement was found on the SIP dimensions "mobility" and "body care and movement" with moderate eVect sizes. Improvement on the SIP subscale "physical health" (P<0.05; eVect size 0.86), the SIP overall score (without "ambulation"), and the "physical health" and overall scale of the HSCL was also significant, with eVect sizes >0.80. Changes in health related behaviour were noted for "sleep and rest" and "recreation and pastimes" (P<0.01, P<0.05; eVect size 0.95 and 0.63, respectively). Psychosocial behaviour showed no improvement. Conclusions-Intrathecal baclofen delivered by an implanted, programmable pump resulted in improved self reported quality of life as assessed by the SIP, and HSCL physical health dimensions also suggest improvement.
Netherlands heart journal : monthly journal of the Netherlands Society of Cardiology and the Netherlands Heart Foundation, 2013
In this review we discuss the position of electrical neuromodulation as a safe and reversible adj... more In this review we discuss the position of electrical neuromodulation as a safe and reversible adjuvant therapy for treatment of patients with chronic cardiac diseases who have become refractory to conventional strategies. In patients with chronic refractory angina, electrical neuromodulation, independent of the applied modality, has shown to reduce complaints of angina, to enhance exercise capacity, to improve quality of life and to employ anti-ischaemic effects. To date, electrical neuromodulation seems to be one of the best adjuvant therapies for these patients. In addition, neuromodulation in the treatment of heart failure and resistant arrhythmias is the subject of several ongoing studies.
Nederlands tijdschrift voor geneeskunde, Jan 21, 2009
Zeitschrift für Kardiologie, 1997
Patients with therapeutically refractory angina pectoris do not respond to adequate anti-anginal ... more Patients with therapeutically refractory angina pectoris do not respond to adequate anti-anginal medication and are not suitable anymore for revascularisation procedures. This group of patients has a poor quality of life, since their exercise capacity is severely afflicted. A new additional therapy for patients with refractory angina is neurostimulation. The concept of neurostimulation is based on the "gate control theory", a model in which nociceptive unmyelinated fiber afferents (C and A delta) are inhibited by non-nociceptive myelinated fiber afferents. Patients treated with spinal cord stimulation (SCS) show an increase in exercise capacity and a concomitant reduction in myocardial ischemia. A reduction in anginal attacks and nitroglycerin intake is also reported. The mechanisms of action of SCS are unclear, although there is evidence of an increase in myocardial oxygen supply, as is shown in peripheral vascular disease. Sympathetic nervous activity, prostaglandins, an...
Advances and Technical Standards in Neurosurgery, 2007
Ischemic disease (ID) is now an important indication for electrical neuromodulation (NM), particu... more Ischemic disease (ID) is now an important indication for electrical neuromodulation (NM), particularly in chronic pain conditions. NM is defined as a therapeutic modality that aims to restore functions of the nervous system or modulate neural structures involved in the dysfunction of organ systems. One of the NM methods used is chronic electrical stimulation of the spinal cord (spinal cord stimulation: SCS). SCS in ID, as applied to ischemic heart disease (IHD) and peripheral vascular disease (PVD), started in Europe in the 1970s and 1980s, respectively. Patients with ID are eligible for SCS when they experience disabling pain, resulting from ischaemia. This pain should be considered therapeutically refractory to standard treatment intended to decrease metabolic demand or following revascularization procedures. Several studies have demonstrated the beneficial effect of SCS on IHD and PVD by improving the quality of life of this group of severely disabled patients, without adversely influencing mortality and morbidity. SCS used as additional treatment for IHD reduces angina pectoris (AP) in its frequency and intensity, increases exercise capacity, and does not seem to mask the warning signs of a myocardial infarction. Besides the analgesic effect, different studies have demonstrated an anti-ischemic effect, as expressed by different cardiac indices such as exercise duration, ambulatory ECG recording, coronary flow measurements, and PET scans. SCS can be considered as an alternative to open heart bypass grafting (CABG) for patients at high risk from surgical procedures. Moreover, SCS appears to be more efficacious than transcutaneous electrical nerve stimulation (TENS). The SCS implantation technique is relatively simple: implanting an epidural electrode under local anesthesia (supervised by the anesthesist) with the tip at T1, covering the painful area with paraesthesia by external stimulation (pulse width 210, rate 85 Hz), and connecting this electrode to a subcutaneously implanted pulse generator. In PVD the pain may manifest itself at rest or during walking (claudication), disabling the patient severely. Most of the patients suffer from atherosclerotic critical limb ischemia. All patients should be therapeutically refractory (medication and revascularization) to become eligible for SCS. Ulcers on the extremities should be minimal. In PVD the same implantation technique is used as in IHD except that the tip of the electrode is positioned at T10-11. In PVD the majority of the patients show significant reduction in pain and more than half of the patients show improvement of circulatory indices, as shown by Doppler, thermography, and oximetry studies. Limb salvage studies show variable results depending on the stage of the trophic changes. The underlying mechanisms of action of SCS in PVD require further elucidation.
Centrale pijn is pijn die veroorzaakt wordt door een laesie in de hersenen, hersenstam, medulla o... more Centrale pijn is pijn die veroorzaakt wordt door een laesie in de hersenen, hersenstam, medulla oblongata of in het myelum. Centrale pijn kan bestaan uit dysesthesieën, hyperpathie, allodynie en pijn van variabele aard, en is in veel gevallen therapieresistent en invaliderend. Elektrostimulatie van de motorische cortex via een operatief ingebrachte intracraniële, epidurale elektrode kan centrale pijn aan de contralaterale lichaamshelft verminderen. Dit wordt motorcortexstimulatie (MCS) genoemd. Het effect van MCS op centrale pijn berust hoogst waarschijnlijk op suppressie van thalame neuronale hyperactiviteit. Naast behandeling van centrale pijn kan MCS ook leiden tot pijnreductie bij patiënten met aangezichtspijn. Een overzicht van de recente studies naar de effectiviteit van MCS op centrale pijn laat zien dat bij globaal de helft van de patiënten met centrale pijn een goed effect wordt bereikt (>50% reductie van pijn op de VAS-score). Mogelijke bijwerkingen zijn epileptische insulten tijdens plaatsing van de elektrode en gedurende per-/postoperatieve proefstimulatie, bloeding in de operatiewond en het optreden van wondinfecties. Om te bepalen wat de haalbaarheid en klinische effectiviteit van MCS bij centrale pijn in Nederland is, worden patiënten momenteel in 2 neurochirurgische centra behandeld binnen een observationele studie. Indicaties voor MCS zijn centrale pijn of aangezichtspijn met de volgende kenmerken: ernstige pijn (VAS score >5), therapieresistentie, invaliderend karakter van de pijn, en lokalisatie in gelaat, thoraxwand of arm (in geval van centrale pijn). Ter illustratie van deze bijdrage wordt een patiënt uit deze observationele studie besproken. MCS lijkt een redelijke behandelingsoptie te zijn bij patiënten met ernstige, therapieresistente en invaliderende centrale of aangezichtspijn. De meeste studies hebben echter een korte follow-up en bevatten kleine aantallen patiënten. Vaak betreft het redelijk jonge patiënten waardoor het van belang is te onderzoeken wat de effecten en complicaties van MCS na 10 tot 20 jaar zijn. Om die reden én om meer duidelijkheid te krijgen over prognostische factoren en over de effectiviteit van MCS in grotere groepen patiënten lijkt het zinvol MCS-behandelingen vooralsnog alleen in trialverband te laten plaatsvinden.
Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1997
ABSTRACT The objective of this work was to design and use a tremor recording and analysis system ... more ABSTRACT The objective of this work was to design and use a tremor recording and analysis system for stereotactic thalamotomy and thalamus stimulation (DBS). A notebook PC based system was developed. The tremor was measured by accelero-transducers or EMG. The method was used to confirm the definitive localization of the coagulation or stimulation target. Intra-operatively recorded effects of stimulation on the tremor were reproducible. Thermocoagulation and electrode implantation were done only after a significant reduction of the tremor was recorded on thalamic stimulation between 75 and 125 Hz. This method has been used on 9 patients: 2 underwent DBS implantation. It is concluded that intra-operative monitoring of the tremor during ventrolateral thalamotomy or stimulation is useful for identifying the final target for coagulation or electrode implantation
Pediatric Neurosurgery, 1987
Twelve patients of 146 hydrocephalic spina bifida aperta patients, treated with a ventricular dra... more Twelve patients of 146 hydrocephalic spina bifida aperta patients, treated with a ventricular drainage system, died suddenly. In 7 of them the cause of death was most probably related to the use of a ventriculovascular shunt, causing pulmonary embolism. Thromboembolic complications were not seen in the 26 hydrocephalic spina bifida patients treated with a ventriculoperitoneal shunt. In 4 other patients shunt malfunction was considered as the cause of sudden death. The case reports of these 11 patients are presented. Pathophysiological mechanisms are discussed and measures for prevention of these two potentially lethal complications are described.
Neurosurgery, 1994
Proton magnetic resonance spectroscopic imaging (1H-MRSI) and positron emission tomography with t... more Proton magnetic resonance spectroscopic imaging (1H-MRSI) and positron emission tomography with the tracer L-[1-11C]tyrosine (11C-TYR) were used to localize gliomas for biopsy or resection. This is especially helpful in cases of low-grade gliomas, if these lesions are not visualized by contrast-enhanced computed tomographic and magnetic resonance imaging scans. The clues to improved localization are provided by changes in tissue metabolite contents, such as elevation of phosphocholine, indicating cellular proliferation; decrease of N-acetylaspartate, denoting loss of neurons (as these are replaced by tumor cells); and elevation of lactate, pointing to the prevalence of glycolysis, as observed in many tumors. These data on tissue metabolite content have been obtained in vivo in the patient by proton magnetic resonance spectroscopy; metabolite maps derived from these data then visualize the distribution of the various metabolites over the section of the brain under investigation. Alternatively, localization of a tumor may be achieved by means of positron emission tomography depicting the pattern of uptake of the amino acid tracer 11C-TYR, as it tends to be incorporated in the process of cellular proliferation and protein biosynthesis. Five cases are presented as examples.
Neuromodulation: Technology at the Neural Interface, 2011
Patients suffering from chronic angina pectoris, insufficiently controllable with medication an... more Patients suffering from chronic angina pectoris, insufficiently controllable with medication and revascularization, are an increasing medical and psychosocial problem. Although spinal cord stimulation (SCS) is proven to employ, safe, long-term anti-angina, and anti-ischemic effects for these patients, the use of SCS in this group remains limited. The reason for this restricted use is largely unknown. However, among other reasons, it may be related to the difficulties in positioning an electrode in the epidural space. We studied the feasibility and efficacy of subcutaneous implantation of an entire system. Seven male patients, mean age 67 ± 3.6 years, received complete subcutaneously implanted electrical nerve stimulation (SENS) systems, with one or more leads fixed in parallel with the sternum, covering the angina area. At baseline and 2 months follow-up patients performed exercise and quality of life tests (Seattle Angina Questionnaire and diaries number angina attacks and glyceryl trinitrate use). All patients showed clinical relevant improvement (baseline vs. follow-up), in exercise (63%) and quality of life (Seattle Angina Questionnaire 59%). The number of angina attacks dropped 82% and the number of glyceryl trinitrate use decreased by 90%. No major adverse events were observed. This small feasibility study demonstrates SENS to be an effective and safe method to treat patients suffering from refractory angina. Furthermore, SENS is less invasive and appears to have less lead migrations compared with SCS.
The Lancet, 1999
The results of several cohort studies suggest that patients with advanced Parkinson&amp;#... more The results of several cohort studies suggest that patients with advanced Parkinson&amp;#39;s disease would benefit from unilateral pallidotomy. We have assessed the efficacy of unilateral pallidotomy in a randomised, single-blind, multicentre trial. We enrolled 37 patients with advanced Parkinson&amp;#39;s disease who had, despite optimum pharmacological treatment, at least one of the following symptoms: severe response fluctuations, dyskinesias, painful dystonias, or bradykinesia. Patients were randomly assigned to unilateral pallidotomy within 1 month or to pallidotomy after the primary outcome assessment (6 months later). The primary outcome was the difference between the groups in median changes on the motor examination section of the unified Parkinson&amp;#39;s disease rating scale (UPDRS 3) score done in the off phase. Secondary outcome measures included levodopa-induced dyskinesias (dyskinesia rating scale [DRS]) and extent of disability (UPDRS 2). The median UPDRS 3 off score of the pallidotomy patients improved from 47 to 32.5, whereas that of control patients slightly worsened from 52.5 to 56.5 (p&amp;lt;0.001). In the on phase the median DRS score improved 50% in pallidotomy patients compared with no change in controls. The UPDRS 2 off score improved with a median of 7 in the pallidotomy group. Two treated patients had major adverse effects. Unilateral pallidotomy is an effective treatment in patients with advanced Parkinson&amp;#39;s disease, who have an unsatisfactory response to pharmacological treatment.
The success of stereotactic pallidotomy procedures is determined by the accuracy of the target fi... more The success of stereotactic pallidotomy procedures is determined by the accuracy of the target finding procedure. The first step always consist of the assignment of the coordinates of target as an anatomical base where X-ray is used. The second step is the final positioning of the stereo tactical placed electrode where the function of targeted neuronal structures has to be monitored. This is usually done by neurological examination of the patient during the procedure. In this study, an instrument is developed that records the finger and hand movements during performance test for bradykinesia as one of the prominent symptoms of the patient and tremor, which is a minor symptom here. Thirteen patients were examined. All were in the `off-state'. Despite patients usually doing well in the performance test, an improvement, expressed in a frequency, is noticed in both the finger tapping and diadochokinesis tests
Nederlands Tijdschrift Voor Geneeskunde, 2009
Clinical Neurology and Neurosurgery, 1997
British Journal of Anaesthesia, 2013
Editor's key points † There are very few methodologically sound studies exploring sympathetic reg... more Editor's key points † There are very few methodologically sound studies exploring sympathetic regulation of CBF. † This review suggests that sympathetic system plays little role in regulating CBF under normal physiological conditions.
Archives of physical medicine and rehabilitation, 2014
To review all pharmacological and physiological data available on intrathecal baclofen (ITB) ther... more To review all pharmacological and physiological data available on intrathecal baclofen (ITB) therapy and to evaluate its use in clinical practice and future research. PubMed was searched for relevant anatomic, physiological, and pharmacological data available on ITB. All currently available data on ITB pharmacokinetics (PKs) and pharmacodynamics (PDs) in both human and animal studies were reviewed and combined with the anatomy and physiology of the intrathecal space and cerebrospinal fluid flow. Only 4 studies reported PK data on ITB in humans. More studies reported PD data on ITB; however, none were combined with PK data. More detailed data on PK could be gathered from studies using an animal model. ITB does not spread equally over the intrathecal space after injection, but it diffuses according to a concentration gradient. ITB distribution can be influenced by the location of the catheter tip and by changing the infusion mode. The pharmacological and physiological data on ITB can ...
Restorative neurology and neuroscience, 1993
In order to establish the number, the viability and the developmental potential of GABAergic neur... more In order to establish the number, the viability and the developmental potential of GABAergic neurons present in dopaminergic ventral mesencephalic (VM) grafts from embryonic rat, we have studied the survival and development of these neurons in culture. The GABAergic fraction demonstrated a highly disproportionate survival in culture in relation to other VM neurons resulting in a drastic change in the neuronal composition of the dissociated VM grafts. The occurrence of a similar gradual dominance of GABAergic neurons at the site of intracerebral implantation, may affect the development of grafted dopaminergic VM neurons and their interaction with host striatal cells.
Stereotactic and functional neurosurgery, 2007
Long-term evaluation of treatment of chronic, therapeutically refractory tinnitus by means of chr... more Long-term evaluation of treatment of chronic, therapeutically refractory tinnitus by means of chronic electrical stimulation of the vestibulocochlear nerve. Inclusion criteria were severe, chronic, therapeutically refractory, unilateral tinnitus and severe hearing loss at the ipsilateral site. Out of 6 patients, 4 patients were selected for long-term evaluation. Two patients were not evaluated because of premature dropout. A stimulation electrode was placed around the vestibulocochlear nerve through a retrosigmoid approach and connected to a subcutaneously positioned pulse generator via an extension cable. Follow-up was performed 3 months and 42.5 months after implantation. Three measures for treatment outcome were used. First, effect sizes were determined by means of the total Tinnitus Handicap Inventory (THI) score using Cohen's formula. Second, general and tinnitus-specific audiometric tests were performed in on and off conditions of the neurostimulation system. Third, record...
Stereotactic and functional neurosurgery, 1990
This study was carried out as a prelude to possible implantations of cultured human fetal dopamin... more This study was carried out as a prelude to possible implantations of cultured human fetal dopaminergic grafts in parkinsonian patients. Examination of fetal rat ventral mesencephalon tissue for morphology, viability, and dopamine content showed an optimal gestational age for neural grafting in rat experiments of approximately 17 days. Moreover, fetal rat ventral mesencephalon tissue was cultured, and neural dopaminergic cells were observed in cell culture in 4 (11%) out of 36 ventral mesencephalon specimens derived from 15- to 21-day-old rat fetuses. Human fetal donor material from elective abortions was examined for morphology and cell culture possibilities. In 48 curettements, fetal tissue was seen in 34 (71%) of these, resulting in 17 (50%) cultures containing dopaminergic cells. Both fetal rat and human cell cultures were continued for approximately 8 weeks and appeared to remain positive upon immunocytochemical dopamine staining.
Stereotactic and Functional Neurosurgery, 1993
There is increasing interest in the use of human fetal dopaminergic tissue as a source of striata... more There is increasing interest in the use of human fetal dopaminergic tissue as a source of striatal transplant in parkinsonian patients. This tissue is acquired by elective abortions. The possibilities of the use of this tissue were studied by macroscopical examination, cell-culturing followed by immunohistochemical staining and by high performance liquid chromatography. It turned out that 50% of the curettages obtained by suction abortion were too fragmented to reliably recognize the dopamine-containing area (ventral mesencephalon). Furthermore, dissection of the brainstem immediately after the abortion procedure seemed to be of utmost importance.