Peripheral nerve field stimulation for chronic neuropathic pain: a single institution experience.

BACKGROUND: Peripheral nerve field stimulation (PNFS) is a novel neurosurgical procedure consisting of implantation of subcutaneous leads in specific painful areas in different types of painful, drug-resistant syndromes. The objective of this study was to evaluate the efficacy of PNFS in several patients affected by different chronic neuropathic pain syndromes, along with its risks, limits and possible correlation between the results achieved and the patients' main symptoms. METHODS: Twenty-two patients affected by different types of chronic neuropathic pain were submitted to PNFS at the Department of Neurosurgery of the Istituto Neurologico "C. Besta" in Milan between July 2009 and July 2013. The visual analog scale (VAS) and variations in the use of analgesic drugs, along with complications, were considered to assess results. RESULTS: In 59 % of our patients, an average pain reduction of 5.50 points on the visual analog scale was observed (average pre-implant score 8.86 and average post-implant score 3.36). These patients reduced their analgesic drug use after PNFS. We observed no early or long-term complications after our last follow-up evaluation. CONCLUSIONS: PNFS can be considered an effective and safe option to treat carefully selected, drug-resistant and chronic neuropathic pain patients; the reversibility of the procedure and its lack, at least in our hands, of long-term complications may contribute to wider use of this procedure.

Intraoperative microrecordings in the posterior hypothalamus of anaesthetized humans with aggressive behaviour.

Two patients with uncontrollable aggressive behaviour underwent the placement of stimulating leads in the posterior hypothalamus (pHyp). One patient had also multifocal refractory epilepsy. Microrecordings were obtained in both patients during surgery under general anaesthesia. Firing rate, interspike intervals and oscillatory discharge patterns were analysed in 14 neurons. A mean discharge rate of 19 Hz, and oscillatory activity at 7-8 Hz were recorded in the first patient with aggressiveness and epilepsy. In the second patient the mean firing rate was 10 Hz, with evidence of both tonic and random firing patterns. Previous studies in patients with cluster headache showed that a discharge rate around 20 Hz and lack of a specific rhythmic pattern were the most consistent characteristics of neuronal discharge in this area. Our present findings therefore would suggest that the pattern of discharge of neurons in the pHyp should be evaluated with reference to the presence of concurrent pathology.

Costs of hypothalamic stimulation in chronic drug-resistant cluster headache: preliminary data.

In about 20% of chronic cluster headache (CH) cases, drugs may become ineffective. Under these circumstances, steroids and triptans are frequently employed leading to fearful side effects in one and high costs in the other. The direct costs of drug-resistant chronic CH are mainly due to frequent medical consultations and frequent use of expensive drugs. In recent years, hypothalamic stimulation has been employed to treat drug-resistant chronic CH patients suffering multiple daily attacks and long-term results from different centres show a 60% overall benefit. Nine years since the introduction of this technique, we attempt a preliminary analysis of the direct costs of hypothalamic stimulation based on patients treated at our centre. We estimated the following direct costs as follows: cost of neurosurgery plus cost of equipment (electrode, connection and impulse generator = 25,000 euro), cost of hospital admissions in long-term follow-up (2,000 euro per admission), cost of single sumatriptan injection (25 euro). Number of daily sumatriptan injections in the year before and for each year after hypothalamic implantation was obtained from headache diaries. To estimate the saving due to the reduction in sumatriptan consumption following hypothalamic stimulation, we calculated the following for each year of follow-up after surgery: number of sumatriptan injections in the year before surgery minus number of sumatriptan injections in each year, updated to December 2008. In our 19 implanted patients, the costs of neurosurgery plus cost of equipment were 475,000 euro; the costs of hospital admissions during follow up were 250,000 euro. Reduction in sumatriptan consumption resulted in a total saving of 3,573,125 euro. Hence, in our 19 patients, the sumatriptan saving (3,573,125 euro) minus the direct costs due to operation and follow up hospitalisations (475,000 + 250,000) euro is equal to 2,848,125 euro. These preliminary results indicate that hypothalamic stimulation is associated with marked reduction of direct costs in the management of complete drug-resistant chronic CH.

Cluster headache and TACs: rationale for central and peripheral neuromodulation.

Cluster headache, the most severe of primary headache conditions for functional and social impairment it provokes, has been recently the object of a great amount of clinical, physiopathological, surgical and functional neuroradiological studies aimed to uncover the real mechanisms which underlie its disabling manifestations. Refinement of methodological and systematic features of multidisciplinary researches in this field has been allowing for more and more precise delineations of the role of both peripheral and central nervous system's contribution in pathophysiology of the disease. Aim of this manuscript is the report of the present knowledge in the role of the different surgical options in the treatment of drug-resistant cluster headache and Short-lasting Unilateral neuralgiform headache attacks with Conjunctival injection and Tearing (SUNCT), which take into account their different hypothesized pathological mechanisms and which comprise central nervous system's approach (Deep Brain Stimulation [DBS] and peripheral approach, namely Occipital Nerve Stimulation (ONS) and Vagal Nerve Stimulation (VNS).

Acute hypothalamic stimulation and ongoing cluster headache attacks.

Long-term hypothalamic stimulation is effective in improving drug-resistant chronic cluster headache (CH). We assessed acute hypothalamic stimulation to resolve ongoing CH attacks in 16 patients implanted to prevent chronic CH, investigating 136 attacks. A pain intensity reduction of > or =50% occurred in 25 of 108 evaluable attacks (23.1%). Acute hypothalamic stimulation is not effective in resolving ongoing CH attacks, suggesting that hypothalamic stimulation acts by complex mechanisms in CH prevention.

Huge epidural hematoma after surgery for spinal cord stimulation.

OBJECTIVE AND IMPORTANCE: Spinal epidural haematoma (SEH) following implantation of an epidural spinal cord electrode is a very rare complication but one that must not be overlooked. This case is unusual because of the almost "holocord" extension of the haematoma and the excellent recovery obtained by prompt surgical treatment. CLINICAL PRESENTATION: A 69 years old man with normal serum coagulation parameters was submitted to spinal cord stimulation (SCS) for chronic pain syndrome. After a minimal L1 laminotomy the patient developed paraplegia due to a large haematoma at D4-L2. INTERVENTION: Surgical removal of the entire clot by a D4-L2 laminectomy was performed immediately. CONCLUSION: Large epidural haematoma can result from SCS and this complication may be cured by appropriate and prompt surgery.

Long-term follow-up of bilateral hypothalamic stimulation for intractable cluster headache.

We provide a detailed case history of the first patient to receive bilateral hypothalamic stimulation to control severe bilateral chronic intractable cluster headaches initially occurring mostly on the left. These attacks were accompanied by life-threatening hypertensive crises and a grave deterioration in the patient's psychological state. Destructive surgery to the left trigeminal was absolutely contraindicated. Electrode implantation and continuous stimulation of the left posterior inferior hypothalamus resolved the left attacks. After four destructive operations on the right trigeminal, right side attacks recurred. Electrode implantation (with continuous stimulation) to the right resulted in immediate resolution of the right side pain and the hypertensive crises. On several occasions, both known and unknown to the patient, the stimulators were turned off: in all cases, crises reappeared and in all instances disappeared relatively quickly after turning stimulation back on. Pain crises have never reappeared when ipsilateral stimulation is ongoing. The only side effects were observed during long-term bilateral stimulation, consisting of transient vertigo and bradycardia. After 42 months (left) and 31 months (right) of follow-up, the patient remains crisis free without the need for pharmacological prophylaxis.

Hypothalamic deep brain stimulation for intractable chronic cluster headache: a 3-year follow-up.

Cluster headache is the most severe among primary headaches. Positron emission tomography and functional MRI studies have demonstrated that the ipsilateral posterior hypothalamus is activated during cluster headache attacks and is structurally asymmetric in these patients thus indicating that cluster headache may originate at that level. These hypothalamic abnormalities in cluster headache led to the suggestion that deep brain stimulation of ipsilateral posterior inferior hypothalamus might produce clinical improvement in otherwise treatment refractory chronic cluster headache patients. In a patient with severe intractable chronic cluster headache, hypothalamic electrical stimulation produced complete and long-term pain relief with no relevant side effects. So far other operations have been performed and the results are encouraging in terms of both pain relief and safety. The efficacy of hypothalamic electrical stimulation provides some hints into cluster headache pathophysiology.

Surgery of Parkinson's disease: inclusion criteria and follow-up.

Parkinson's disease (PD) is a progressive disturbances of movement that affects mainly the motor system. Prolonged pharmacological administration may result in insufficient control of symptoms and significant side effects. Deep brain stimulation (DBS), targeted at the STN, is a recent surgical procedure that, according to the symptoms response, allows modification of stimulation parameters; its effects are also reversible. In this paper management of surgical patients is reported. It includes patient selection, inclusion and exclusion criteria, postoperative clinical protocol. The evaluation rating scale such as UPDRS, Dyskinesias Rating Scale and Self-Reporting Questionnaire usually administrated on PD patients are analyzed. Surgical inclusion criteria are (1) idiopathic PD, (2) IV or V Hoehn-Yahr stage, (3) severe motor disability, and (4) no dementia or psychiatric abnormalities. Postoperative clinical protocol is analyzed and parameter of stimulation after surgery and at the follow up are reported. Generally DBS allows an improvement of rigidity and tremor; bradykinesia also improves with high frequency stimulation. Results obtained by continuous stimulation show a mean improvement of UPDRS of about 60% and a significant reduction in the drug intake.

CT-guided neurosurgery: preliminary experience.

BACKGROUND: With the possibility of CT systems becoming more handy and sophisticated, intraoperative CT was introduced in a few neurosurgical Centres with better results in lesion removal and surgical outcome. METHOD: At our Institution a mobile CT scanner was recently used for intraoperative evaluation (Philips Tomoscan M). For 27 tumour resections performed with a neuronavigation system, and 23 deep brain electrode positioning examinations, an intraoperative CT was employed. In addition the CT scanner was used in the recovery room for a postoperative control in 198 patients. FINDINGS: Our preliminary experience used for a real time evaluation of the treated patients, permitted to verify an incomplete removal in 23/27 cases. Evaluation of stereotactic electrode position in relation to the planned target was also possible and demonstrated a correct position in 21 cases. INTERPRETATION: Intraoperative CT scan is a useful system that permits to modify neuronavigation planning and is able to give information to the surgeon for better tumour removal, rule out possible hemorrhagic complications, and suitable deep brain electrode positioning.

Effect of bilateral subthalamic electrical stimulation in Parkinson's disease.

BACKGROUND: Bilateral high frequency subthalamic stimulation has been reported to be effective in the treatment of Parkinson's disease and levodopa-induced dyskinesias. To analyze the results of this surgical procedure we critically reviewed 17 parkinsonian patients with advanced disease complicated by motor fluctuations and dyskinesias. METHODS: Between January 1998 and June 1999 these 17 consecutive patients (age 48-68 years; illness duration 8-27 years) underwent bilateral stereotactically guided implantation of electrodes into the subthalamic nucleus in the Department of Neurosurgery of the Istituto Nazionale Neurologico "C. Besta." Parameters used for continuous high-frequency stimulation were: frequency 160 Hz, pulse width 90 microsec, mean amplitude 2.05 +/- 0.45 V. Parts II and III of the UPDRS were used to assess motor performance before and after operation by the neurologic team. The follow-up ranged between 6 and 18 months. RESULTS: At latest examination, mean UPDRS II and III scores had improved by 30% (on stimulation, off therapy) with mean 50% reduction in daily off time. Peak dyskinesias and early morning dystonias also improved in relation to therapy reduction. Side effects were persistent postoperative supranuclear oculomotor palsy and postural instability in one case, worsened off-medication hypophonia in three, and temporary nocturnal confusion episodes in three. Postoperative MRI revealed a clinically silent intracerebral haematoma in one case. One electrode required repositioning. CONCLUSIONS: Continuous high frequency STN stimulation is an effective treatment for advanced PD. A functionally useful and safe electrode placement can be performed without microrecording.

[Contribution of thalamotomy, cordotomy and dorsal root entry zone Caudalis trigeminalis lesions in the treatment of chronic pain]. / Le rôle de la thalamotomie, de la cordotomie et de la lésion de la dorsal root entry zone (DREZ) Caudalis trigeminalis dans le traitement de la douleur chronique.

Ablative neurosurgical methods are mainly proposed in cases of nociceptive pain, but, at present, medical treatments and local pharmacotherapy (intrathecal and intracerebroventricular) are often very effective in this context. Moreover, neuropathic pain is well controlled by äugmentative techniques, except painful paroxysms. If a destructrive method is necessary, it is selective, performed according to precise neurophysiological and anatomical data with the frequent use of percutaneous and/or stereotactic techniques: the lesion of caudalis DREZ in treatment of neuropathic trigeminal pain, the antero-lateral cordotomy in the treatment of unilateral severe cancer pain and several kinds of thalamotomy.

Reversal of thalamic hand syndrome by long-term motor cortex stimulation.

The authors describe a case of complete recovery from the so-called "thalamic hand" syndrome following chronic motor cortex stimulation in a 64-year-old man suffering from poststroke thalamic central pain. As of the 2-year follow-up examination, the patient's dystonia and pain are still controlled by electrical stimulation. It is speculated that a common mechanism in which the thalamocortical circuit loops are rendered out of balance may sustain hand dystonia and central pain in this case of thalamic syndrome. To the authors' knowledge this is the first reported case of its kind.

Low-grade glial tumors in basal ganglia and thalamus: natural history and biological reappraisal.

The natural history of 70 patients affected by low-grade astrocytomas was recorded after the histological diagnosis was obtained by serial stereotactic biopsy. Forty-three percent of these patients died within 3 years. The value of cell kinetics assessment at the time of stereotactic biopsy was investigated, and the labeling index percent may be considered the most accurate prognostic factor in these histologically homogeneous astrocytomas. It has been confirmed that the young age of patients predicts a more favorable course, but the value of this also seems to be linked to and dependent on cell kinetics. These data are discussed in view of the opportunity to perform more aggressive "cytoreductive" treatments in deep brain tumors when these indices support an expected poor prognosis.

Epidural stimulation for peripheral vascular disease: 10 years experience.

105 patients suffering from arteriosclerotic peripheral vascular disease (PVD) underwent epidural spinal stimulation in the last 10 years. Before 1986 the main indication was ischemic pain without any consideration of trophic lesions (19 pts) while afterward the selection of the patients was more accurate in terms of disease's stage. The analysis of the data shows a more favourable results in the second group. Our experience suggest to use this technique in the treatment of patients in Fontaine's stage III and IV without necrosis and large trophic lesions.

Long term results of stereotactic thalamotomy for cerebral palsy.

A group of 33 patients (between 10 and 30 years old and with average intelligence) underwent stereotactic surgery for abnormal movements due to cerebral palsy. Neurological, neurofunctional, and neuropsychological examinations were performed pre- and postoperatively. The length of follow-up ranged between 1 and 4 years. The clinical results are reported and discussed in relation to the targets, the side of the lesion, and the clinical picture. Our data show that better results are obtained in patients with tremor and hyperkinesias; dystonia is improved to a lesser extent, whereas spasticity tends to recur. Operation is more effective for patients with unilateral signs than for patients with bilateral symptoms. The clinical results are stable in time, and the side effects fade away after a few months.