Geert H. Spincemaille

Management of hardware infections following deep brain stimulation

SummaryObjective. To report our experience on hardware-related infections following deep brain stimulation (DBS). Methods. The present article presents the retrospective clinical notes review of gained in a two-centre, single-surgeon study experience of 108 consecutive DBS cases between 1996 and 2002. In all patients the minimum follow-up was six months. One hundred and eight patients received an intracerebral electrode implantation and 106 underwent internalization. Results. In total 178 electrodes were implanted with a mean follow-up of 42.6 months and a cumulative follow-up of 367.7 patient-years. Four patients (3.8%) developed an infection related to the DBS-hardware and all were initially treated with antibiotics. Two patients eventually required additional surgical treatment. Conclusion. Infections due to DBS-hardware can result in considerable levels of morbidity. In certain cases antibiotic therapy may be adequate. In others, surgical intervention to externalise the electrodes may be necessary. In our experience, there was never a need to remove the electrodes.

Differential effects of subthalamic nucleus stimulation in advanced Parkinson disease on reaction time performance

The aim of the present study was to assess the effect of bilateral subthalamic nucleus (STN) stimulation and dopaminergic medication on speed of mental processing and motor function. Thirty-nine patients suffering from advanced Parkinson disease (PD) were operated on. Motor function and reaction time (RT) performance [simple RT (SRT) and complex RT (CRT)] were evaluated under four experimental conditions with stimulation (stim) and medication (med) on and off: stim-on/med-on, stim-on/med-off, stim-off/med-off and stim-off/med-on. In the last condition, the patients received either low medication (usual dose) or high medication (suprathreshold dose). STN stimulation improved the motor performance in the SRT and CRT tasks. Furthermore, STN deep brain stimulation (DBS) also improved response preparation as shown by the significant improvement of the RT performance in the SRT task. This effect of STN DBS on the RT performance in the SRT task was greater as compared with the CRT task. This is due to the more complex information processing that is required in the CRT task as compared to the SRT task. These data suggest that treatment of STN hyperactivity by DBS improves motor function, confirming earlier reports, but has a differential effect on cognitive functions. The STN seems to be an important modulator of cognitive processing and STN DBS can differentially affect motor and associative circuits.

Safety and one-year efficacy of intrathecal baclofen therapy in children with intractable spastic cerebral palsy

BACKGROUND Prospective studies that address both efficacy and safety of continuous infusion of intrathecal baclofen (CITB) in children with spastic cerebral palsy (CP), and that use outcome measures beyond muscle tone are lacking. AIMS To study the efficacy at 12 months and safety up to 24 months after start of CITB in children with intractable spastic CP. METHODS Nine girls and eight boys, aged 13.7 years (SD 2.9), received a SynchroMed pump for CITB. We prospectively recorded effects and adverse events at regular follow-up visits up to 24 months. Outcome measures included the 0-10 visual analogue scale (VAS) for individual problems, Gross Motor Function Measure (GMFM) and health related quality of life as measured with the Child Health Questionnaire-PF50. RESULTS CITB for 12 months significantly improved the VAS for individual problems with 4.7 (SD 2.0; p=0.000), VAS for ease of care with 5.2 (SD 2.1; p=0.000), VAS for pain with 5.4 (SD 2.7; p=0.002); GMFM sitting dimension with 3.3 (range -4.0 to 22.0; p=0.022), GMFM goal dimension with 4.0 (range 0.0-26.0; p=0.007); and Child Health Questionnaire-PF50 domains of bodily pain/discomfort with 25.6 (SD 35.9; p=0.016) and mental health with 9.8 (SD 11.3; p=0.007). During a mean follow-up of 18.4 months (range 12-24), we recorded 80 adverse events. Eight adverse events were serious, but not life-threatening. CONCLUSIONS CITB was effective at 12 months and safe up to 24 months for carefully selected children with intractable spastic CP. CITB relieved pain, facilitated ease of care and improved mental health. The majority of children could extend their activities and participation.

Deep brain stimulation of the thalamus can influence penile erection.

Penile erection is a complex neurovascular event. It is controlled by a spinal generator network and a supraspinal controlling system and their reciprocal interactions. The role of the spinal system has been extensively described. On the other hand, little is known about the supraspinal control, specifically about the role of the thalamus. Two patients underwent successful bilateral highfrequency stimulation (HFS) of the thalamus for Tourette’s syndrome (TS). TS is a chronic neurological disorder characterized by vocal and motor tics. The onset is generally in childhood and the disease is frequently self-limiting. A small number of patients, however, remain symptomatic and usually require pharmacological treatment. In 1999, Vandewalle et al introduced chronic deep brain stimulation (DBS) of the thalamus as a treatment for intractable TS. There are no specific sexual disorders linked to TS. The two patients of this study experienced changes in penile erection in response to sexual stimuli, after the surgery. The first patient reported an increased frequency and amplitude of erection to erotic stimuli, whereas the second patient reported an inhibited erection during intercourse which forced him to turn off the stimulator. In the present study, penile erection in stimulation on and off conditions has been examined in a laboratory setting to investigate the role of the thalamus in erection.

Monopolar versus bipolar high frequency stimulation in the rat subthalamic nucleus: differences in histological damage

The aim of the present study was to determine the effects of monopolar and bipolar high frequency stimulation (HFS) on histological damage and current flow using a commonly applied stimulus amplitude (300 microA). Bipolar HFS resulted in a large amount of histological damage whereas with monopolar HFS no damage was observed except for the electrode trajectory. Oscilloscopic readings confirmed that this was due to the application of twice as much current to the target with bipolar HFS. Our results demonstrate that there are differences in tissue damage dependent of polarity. In order to create a better comparison to the clinical condition, we suggest that the present rodent models for studying the effect of chronic HFS require further adjustment. This can be achieved by decreasing the present current densities to a level comparable to the human situation.

Upregulation of the GABA-transporter GAT-1 in the spinal cord contributes to pain behaviour in experimental neuropathy

Sciatic nerve ligation in rats (chronic constriction injury (CCI)) induces signs and symptoms that mimic human conditions of neuropathy. The central mechanisms that have been implicated in the pathogenesis of neuropathic pain include increased neuronal excitability, possibly a consequence of decreased availability of spinal GABA. GABA availability is regulated by the presence of the GABA-transporters (GATs). This study investigates the dorsal horn expression of the transporter GAT-1 and its functional involvement towards pain behaviour in the CCI model. Male Lewis rats (total n=37) were subjected to CCI or to a sham procedure. A sub-group of animals was treated with the GAT-1 antagonist NO-711. Behavioural testing was performed pre-surgery and at 7 days post-surgery. Testing included evaluation of mechanical allodynia using Von Frey filaments, thermal allodynia with a hot-plate test and observational testing of spontaneous pain behaviour. Subsequently, spinal protein expression of GAT-1 was assessed by Western blotting. Animals were sacrificed 7 days following surgery. CCI markedly increased mechanical and thermal allodynia and spontaneous pain behaviour after 7 days, while the sham procedure did not. GAT-1 was increased in spinal cord homogenates compared contralateral to the ligation side after 7 days. NO-711 treatment significantly reduced all tested pain behaviour. These data provide evidence for possible functional involvement of GAT-1 in the development of experimental neuropathic pain. The latter can be derived from observed analgesic effects of early treatment with NO-711, a selective GAT-1 inhibitor. The obtained insights support the clinical employment of GAT-1 inhibitors to treat neuropathic pain.

Occipital nerve stimulation in medically intractable, chronic cluster headache. The ICON study: rationale and protocol of a randomised trial.

Background About 10% of cluster headache patients have the chronic form. At least 10% of this chronic group is intractable to or cannot tolerate medical treatment. Open pilot studies suggest that occipital nerve stimulation (ONS) might offer effective prevention in these patients. Controlled neuromodulation studies in treatments inducing paraesthesias have a general problem in blinding. We have introduced a new design in pain neuromodulation by which we think we can overcome this problem. Methods/design We propose a prospective, randomised, double-blind, parallel-group international clinical study in medically intractable, chronic cluster headache patients of high- versus low-amplitude ONS. Primary outcome measure is the mean number of attacks over the last four weeks. After a study period of six months there is an open extension phase of six months. Alongside the randomised trial an economic evaluation study is performed. Discussion The ICON study will show if ONS is an effective preventive therapy for patients suffering medically intractable chronic cluster headache and if there is a difference between high- and low-amplitude stimulation. The innovative design of the study will, for the first time, assess efficacy of ONS in a blinded way.

Placebo controlled utility and feasibility study of the H-reflex and flexor reflex in spastic children treated with intrathecal baclofen

OBJECTIVE To evaluate feasibility and utility of the soleus H-reflex and tibialis anterior flexor reflex (FR) in identifying spinal cord neuronal response to intrathecal baclofen (ITB) in children with severe spastic cerebral palsy. METHODS During a randomized, double-blind, placebo-controlled dose-escalation test treatment, maximum H amplitude/maximum M amplitude (H/M ratio) and FR parameters were bilaterally recorded at baseline and 2-3 h after intrathecal bolus administration of placebo and increasing doses of baclofen until both an improvement in the individual treatment goal(s) and a one-point reduction on the Ashworth scale were observed. RESULTS Electrophysiological data of 14 children were studied. The H-reflex was feasible in 13 children, the FR threshold area in 9 and the FR, elicited with supramaximal stimulation, in only one child. After ITB, the H/M ratio significantly decreased (left: 0.67+/-0.47 to 0.15+/-0.18, P=0.005; right: 0.55+/-0.32 to 0.14+/-0.19, P=0.002) without placebo effect. FR threshold area after ITB, only decreased significantly in children not taking oral baclofen (left: 146+/-53 to 41+/-54 mV ms, P=0.000; right: 156+/-80 to 66+/-48 mV ms, P=0.002). CONCLUSIONS This is the first randomized, double-blind, placebo-controlled dose-escalation study in spastic children demonstrating the soleus H-reflex to be a feasible and objective measure to quantify the decreasing motoneuron excitability in response to ITB bolus administration. Only in children not taking oral baclofen, FR threshold area can also be used as an objective outcome measure, yet feasibility is limited. SIGNIFICANCE We suggest introducing the H-reflex as the electrophysiological gold standard for the evaluation of the effect of ITB in spastic children.

Subcutaneous Stimulation as ADD-ON Therapy to Spinal Cord Stimulation Is Effective in Treating Low Back Pain in Patients With Failed Back Surgery Syndrome: A Multicenter Randomized Controlled Trial.

Suppression of back pain with traditional spinal cord stimulation (SCS) in failed back surgery syndrome patients is often insufficient. The objective of this study was to investigate the efficacy of subcutaneous stimulation (SubQ) as ADD‐ON therapy to SCS in treating back pain in failed back surgery syndrome patients.

P23.1 Placebo-controlled feasibility and utility study of the H-reflex in spastic children treated with intrathecal baclofen

autoimmune lesion associated status dissociatus. Clinical case: A 60-year-old man, previously healthy, with acute distal hyporreflexive progressive tetraparesis. The cerebral spinal fluid (CSF) showed albumino-cytological dissociation and the electromyogram (EMG) documented a demyelinating motor neuropathy consistent with the diagnosis of Guillain-Barre syndrome. There was progressive worsening of the paresis, slight disautonomia developed and, on the 14th day of disease, the patient became somnolent and started to have delusions, vivid dreams and constant confusion between dreams and reality. The CSF had high protein content and the EMG documented axonal damage on the four limbs and severe right frenic nerve demyelination. The polysomnography (PSG) showed a fragmented sleep with near total absence of slow wave sleep, a high percentage of status dissociatus (27% of all epochs) and loss of atonia in REM sleep. The apnea/hypopnea index (AHI) during REM sleep was 30.4. The multiple sleep latency test confirmed excessive daytime sonolence and there were no sleep onset REM periods. After 2 weeks, the patient recovered from the mental status changes. The PSG revealed normal progression of sleep phases across the night with long periods of wakefulness. Status dissociatus was only found in 5.7% of sleep epochs but there was still REM sleep without atonia. The AHI during REM sleep was 12.7. Discussion: This report shows that there is a close temporal relationship between status dissociatus and mental status changes in Guillain-Barre syndrome. The associated diaphragmatic paresis of this patient and the high respiratory distress found on REM periods suggests, however, that REM deprivation might also contribute to this state.