Vagus nerve stimulation for epilepsy activates the vocal folds maximally at therapeutic levels.

PURPOSE: Vagus nerve stimulation (VNS) for medically refractory epilepsy can give hoarseness due to stimulation of the recurrent laryngeal nerve. For a group of VNS-therapy users this side-effect interferes severely with their daily activities. Our goal was to investigate the severity of intra-operative VNS-related vocal fold contraction at different pulse widths and current output parameters. We investigated electromyographic and morphometric alterations on the vocal folds during VNS. METHODS: Vocal fold EMG experiments were conducted intra-operatively during the implantation of a VNS system. During surgery the VNS pulse generator was programmed to stimulate at different pulse durations. At each pulse width the EMG-threshold current was determined by electrical stimulation of the vagus nerve with increasing stimulation currents. Laryngostroboscopic examination was performed after surgery to analyze the effects of spontaneous stimulation on the larynx. RESULTS: The vocal fold EMG and morphodynamic changes in the larynx have been analyzed in eight patients. In all patients left vocal fold EMG-threshold was between 0.25 and 0.50 mA. Pulse duration had little influence on the EMG-threshold level. Vocal fold EMG saturation levels were reached between 0.75 and 1.00 mA. Video stroboscopic monitoring showed that stimulation induced an adductory spasm of either the ipsilateral vocal fold or the vestibular fold, and was present remarkably irrespective of the presence of hoarseness. CONCLUSIONS: VNS causes pronounced effects on the vocal folds even at low stimulation amplitudes. At therapeutic levels even at the lowest stimulation pulse durations, the vocal fold contract, however, this does not necessarily give hoarseness.

Cardiac responses of vagus nerve stimulation: intraoperative bradycardia and subsequent chronic stimulation.

OBJECTIVES: Few adverse events on heart rate have been reported with vagus nerve stimulation (VNS) for refractory epilepsy. We describe three cases with intraoperative bradycardia during device testing. PATIENTS AND METHODS: At our hospital 111 patients have received a VNS system. Intraoperative device testing is performed under ECG-monitoring. We reviewed the patients and their VNS-therapy follow-up outcome who experienced a change in heart rate, during device testing (Lead Test). RESULTS: Three patients with medically refractory epilepsy showed a bradycardia during intraoperative Lead Test. Postoperative the VNS-therapy started under ECG-monitoring. No change in cardiac rhythm occurred. Subsequent chronic stimulation is uneventful. All three have reduced seizure frequency. Two already have had their second implant, without the occurrence of bradycardia. CONCLUSION: In case of intraoperative bradycardia VNS-therapy onset should be done under ECG-monitoring. Subsequent chronic stimulation is safe in respect to heart rate. Bradycardia during intraoperative device testing is no reason to abort the operation.

Vagus nerve stimulation for medically refractory epilepsy: a long-term follow-up study.

INTRODUCTION: Vagus nerve stimulation (VNS) is thought to have a cumulative effect in time on seizure frequency reduction. There also might be other variables than reduction of seizure frequency in order to determine VNS efficacy. In this study we describe the long-term outcome of the first group of vagus nerve stimulation patients with pharmacoresistant epilepsy at the Medisch Spectrum Twente, The Netherlands. METHODS: This long-term descriptive prospective study included 19 patients, 11 males and 8 females, aged 17-46 years with pharmacoresistant epilepsy. They had received 3-16 (mean 9) different anti-epileptic drugs and were not eligible for surgical resection of an epileptic focus. A vagus nerve stimulator was implanted in the period April 1999-October 2001. Follow-up ranges from 2 to 6 years (mean 4 years). Efficacy was measured as the percentage change in seizure rate during 1 year and then after each year follow-up of VNS compared to 5 months baseline before implantation. RESULTS: Mean seizure reduction at 1-6 years was, respectively, 14% (n = 19), 25% (n =1 9), 29% (n = 16), 29% (n = 15), 43% (n = 9) and 50% (n = 7). Because of VNS two patients were able to start living without supervision. One patient died after 2 years of follow-up possibly as a result of SUDEP. Four patients had no apparent reduction in seizure frequency. Two of them had their stimulator removed. The other two patients however had significantly reduced post-ictal periods and seizure time and received a new pulse generator when the battery was depleted. One stimulator was switched off due to adverse effects, even though there was a positive effect on his seizure reduction. In six patients the medication regimen was changed during VNS by adding one anti-epileptic drug, however without significant change in seizure reduction. Adverse effects were hoarseness and coughing during stimulation. One patient had a temporary paralysis of his left vocal cord. CONCLUSION: We think that VNS is an effective treatment for pharmacoresistant epilepsy and its positive effect persists during the years of follow-up. Our results suggest that seizure reduction should not be considered as the only variable of importance to describe the outcome of VNS on epilepsy and it is worthwhile to look at other outcome measures.

A 7-year follow-up of sacral anterior root stimulation for bladder control in patients with a spinal cord injury: quality of life and users' experiences.

STUDY DESIGN: Cross-sectional descriptive study. OBJECTIVES: To assess long-term effects and quality of life (QoL) of using sacral anterior root stimulation (SARS) in spinal cord injured patients. SETTING: Neurosurgical and Urological Departments of a large teaching hospital and a large rehabilitation centre in the Netherlands. METHODS: In all, 42 patients with complete spinal cord injury (SCI) implanted between 1987 and 2000 were included. A questionnaire was constructed to determine complications, technical failures and personal experiences of the patients. The Qualiveen questionnaire was used and the outcome was compared with data obtained from a reference group of 400 SCI patients with neurogenic bladder problems not using the bladder controller. The Qualiveen questionnaire measures disease-specific aspects in four domains with respect to limitations, constraints, fears and feelings and general QoL aspects, suitable for use in SCI patients with urinary disorders. RESULTS: The results of 37 patients are presented. Our results with the bladder controller with respect to medical and technical complications and infection rates are similar to the results presented by others. From users' experiences, the most important advantages reported were a decreased infection rate (68%), improved social life (54%) and continence (54%). Comparison of the obtained results of our patient group with the Qualiveen questionnaire with a reference group not using the bladder controller indicates that the specific impact of urinary disorders in the four domains on QoL is reduced and that general QoL is improved. CONCLUSION: SARS is effective and safe for neurogenic bladder management in patients with complete SCI. Users' experiences are positive. Furthermore, this therapy seems to reduce the effects of urinary-disorder-specific QoL aspects, and to increase the QoL in general.

Application of a dual channel peroneal nerve stimulator in a patient with a "central" drop foot.

Dropped foot is a common mobility problem amongst patients after a cerebro vascular accident. The condition arises from paresis of the muscles that control the foot movement during the swing phase of gait. If the abnormal movement is not compensated for, it results in a significant decrease in the mobility and hence quality of life. Compensation for the drop foot can be achieved through the application of functional electrical stimulation. To date, in the clinical environment, the stimulation has been applied through electrodes placed on the skin over the common peroneal nerve, and using a single channel implant device. It is well known that with these techniques it is difficult to establish a balanced response of the foot. An implantable dual channel system for stimulation of the deep and superficial peroneal nerve has now been developed for patients with a drop foot following a stroke. By stimulation of the two branches of the common peroneal nerve separately it is possible to achieve a precisely balanced dorsal flexion and eversion of the foot. Stimulation occurs via small bipolar electrodes which are placed subepineural. After successful tests on animals we have now started the two channel peroneal nerve stimulator implantation in patients. The preliminary results of the first implants are presented.

Intracerebral haemorrhage in neurofibromatosis type I.

Neurofibromatosis type I patients usually present themselves with multiple neurofibromas and cafe-au-lait spots. We report a case with an intracerebral haemorrhage as an uncommon feature of the disease. The clinical, radiological, neurosurgical and histological features of this case are discussed and a review of the literature on the broad spectrum of neurofibromatosis is presented. The etiological factors and clinical consequences of this and other cerebrovascular features are briefly discussed.

[Vagus nerve stimulation in patients with drug-resistant epilepsy]. / N.-vagusstimulatie bij patiënten met medicatieresistente epilepsie.

OBJECTIVE: To describe the mechanism and first results of vagus nerve stimulation at the Medisch Spectrum Twenty, the Netherlands, for the treatment of patients with drug-resistant epilepsy. DESIGN: Descriptive retrospective. METHOD: Fifteen patients, 8 male and 7 female, aged 18-45 years with drug-resistant epilepsy, who were not eligible for surgical resection of an epileptic focus, received a vagus nerve stimulator implant in the period April 1999-December 2000. Whilst the vagus nerve stimulator was being adjusted, the medication remained unchanged. RESULTS: Due to vagus nerve stimulation the mean seizure frequency decreased by 32% (range: +20% to -100%). In 6 patients there was a strong reduction in seizure frequency, in 3 there was a mild reduction, and in 6 patients there was no apparent effect. The most common adverse events during stimulation were a mild prickly cough and a change of voice during stimulation. In one patient a temporary left vocal cord paralysis was observed, which may possibly have been a result of the procedure. CONCLUSION: Vagus nerve stimulation is an effective means of treatment for drug-resistant epilepsy and is therefore a treatment option that deserves more attention in the Netherlands.

Is leg length discrepancy associated with the side of radiating pain in patients with a lumbar herniated disc?

STUDY DESIGN: The association between leg length discrepancy and the side of the radiating pain in lumbar disc herniation was investigated in a case series. OBJECTIVES: To investigate whether pain tends to radiate into the longer or shorter leg in patients with a lumbar herniated disc. SUMMARY OF BACKGROUND DATA: No previous studies have investigated the association between leg length discrepancy and side of radiating pain in patients with a herniated disc. Results of studies of low back pain with radiation and leg length discrepancy are inconsistent concerning this association. METHODS: Of 132 consecutive patients admitted to a district hospital for surgical management of a lumbar herniated disc, leg length discrepancy was assessed using the indirect method as described by Calliet. RESULTS: Seventy-three patients (55%) were men, and 59 (45%) were women. The mean age was 40 years, and 99% of all herniated discs appeared at L4-L5 (n = 60) or L5-S1 (n = 71). In 64 (62%) of the 104 patients with a leg length discrepancy of 1 mm or more, the pain radiated in the shorter leg (P = 0.02). In subgroups of patients with larger leg length discrepancies, similar results were found but because of smaller sample sizes, these findings did not each statistical significance. In 32 of the 57 men (56.1%), the pain radiated to the shorter leg (P = 0.43); this was observed in 33 of the 47 women (70.2%; P = 0.01). CONCLUSION: The results of this study showed a statistically significant association between leg length discrepancy and the side of radiating pain in a case series of patients with lumbar herniated discs. The relation was more pronounced and statistically significant in women only.

Sacral anterior root stimulation for bladder control: clinical results.

The Brindley bladder stimulator delivers intermittent stimulation to the anterior sacral roots. The stimulus parameters can be adjusted and set specifically for individuals. Its primary purpose is to improve bladder emptying, thereby to eliminate urinary infection and to preserve kidney function. It also assists in defecation and enables male patients to have a sustained full erection. In our unit so far 38 patients with a complete spinal cord lesion have received a Brindley bladder stimulator implant. One patient died 2 weeks after the surgery due to pulmonary embolism. Two other patients died due to unrelated causes during the follow up period. They used their implants for less than 1 year. Results relating to these 2 patients and the remaining 35 patients who regularly use their implant are presented. The follow-up period ranged from 3 months to 12 years. Residual urine volumes are substantially reduced in all patients; in 24 patients the residual urine volume is less than 30 ml. All patients have increased bladder capacity. Thirty-one patients are continent. Out of 33 males 29 can achieve a sustained full erection using the stimulator. Twenty-seven patients use the implant for bowel function. The following complications were encountered: (1.) Cerebro-spinal fluid collection occurred around the implant in 3 patients during the post-operative period; (2.) Receiver failure occurred in 3 patients. A successful replacement with a new receiver block was carried out in these cases. It is concluded that the use of a bladder stimulator in selected patients gives long term favourable results.

MRI locates a posterior fossa aneurysm in the fourth ventricle.

We report a rare case of a ruptured aneurysm of the choroidal branch of the left posterior inferior cerebellar artery (PICA) located in the fourth ventricle. Digital subtraction angiography revealed this PICA aneurysm but the exact location remained unknown. The unique location in the fourth ventricle was subsequently shown by magnetic resonance imaging (MRI). The patient died and the final diagnosis was confirmed by autopsy. To our knowledge, this is one of the few reported cases of a PICA aneurysm in the fourth ventricle and the only one which was confirmed by the combination of MRI and autopsy.

Sacral rhizotomies and electrical bladder stimulation in spinal cord injury. Part I: Clinical and urodynamic analysis. Dutch Study Group on Sacral Anterior Root Stimulation.

OBJECTIVES: To present the clinical and urodynamic results of the treatment of neurogenic bladder dysfunction in spinal cord injury by sacral rhizotomies and electrical bladder stimulation with the Finetech-Brindley stimulator during a 3-year inclusion and study period. METHODS: 226 patients with spinal cord lesion and urological problems due to hyperreflexia of the bladder were screened for sacral rhizotomies and electrical bladder stimulation. In 52 patients complete posterior sacral root rhizotomies were performed and a Finetech-Brindley sacral anterior root stimulator implanted. All patients were screened and followed with a standard protocol. RESULTS: Complete continence during daytime was achieved in 73% of patients with 6-month follow-up and in 86% at night. Significant increase in bladder capacity and bladder compliance was achieved in all patients. Residual urine was reduced significantly, resulting in a decrease of the incidence of urinary tract infections. CONCLUSIONS: The treatment of neurogenic bladder dysfunction in spinal cord injury by anterior sacral root stimulation with the Finetech-Brindley stimulator in combination with sacral posterior root rhizotomy produces excellent results with limited morbidity.

Sacral anterior root stimulation for bladder control in patients with a complete lesion of the spinal cord.

A Finetech-Brindley bladder controller was implanted in 17 patients with a complete lesion of the spinal cord. During a microscopic procedure in the cauda equina, the sacral roots were identified and the posterior components of the S2, S3 and S4 roots were cut. The stimulator was placed intradurally around the anterior components of the S2, S3, S4 roots and the S5 root. Our patients have now been followed-up for periods varying between 1 and 6 years. In all 17 patients, the bladder capacity has been increased; 16 patients have a residual volume of less than 30 ml, urinary tract infection is rare; 12 patients are fully continent. All male patients can achieve a full sustained erection by means of the implant and 13 patients are using the implant for bowel function. The method has no significant harmful effects or complications.

A comparative trial of the analgesic effect of tiaprofenic acid and indomethacin in post-operative pain following spinal surgery in patients with radicular syndrome.

A randomized double-blind trial was carried out in 80 patients with post-operative pain after discectomy to relieve chronic radicular syndrome, to compare the analgesic effectiveness and tolerance of tiaprofenic acid and indomethacin. Patients received either 600 mg tiaprofenic acid or 75 mg indomethacin per day, in 3 divided doses, on the day of the operation and for the next 4 days. The results of patient assessment of pain severity showed a statistically significant greater relief on the day of operation in the tiaprofenic acid group and lower pain scores were recorded on each of the 4 following days than in patients receiving indomethacin, although the difference did not reach statistical significance on any of these days. Fewer patients reported side-effects after tiaprofenic acid treatment but once again the difference between the two groups was not significant.