Michele Rizzi

Deep brain stimulation for movement disorders. Considerations on 276 consecutive patients

The links between Stn DBS and advanced Parkinson disease, and between GPi DBS and dystonia are nearly universally accepted by the neurologists and neurosurgeons. Nevertheless, in some conditions, targets such as the ventral thalamus and the Zona Incerta may be considered to optimize the results and avoid the side effects. Positive and negative aspects of current DBS treatments justify the research of new targets, new stimulation programs and new hardware. Since 1993, at the Istituto Nazionale Neurologico “Carlo Besta” in Milan, 580 deep brain electrodes were implanted in 332 patients. 276 patients were affected by movement disorders. The DBS targets included Stn, GPi, Voa, Vop, Vim, CM–pf, cZi, IC. The long-term follow-up is reported and related to the chosen target. DBS gave a new therapeutic option to patients affected by severe movement disorders, and in some cases resolved life-threatening pathological conditions that would otherwise result in the death of the patient, such as in status dystonicus, and post-stroke hemiballismus. Nevertheless, the potential occurrence of severe complications still limit a wider use of DBS. At today, the use of DBS in severe movement disorders is strongly positive even if further investigations and studies are needed to unveil potential new applications, and to refine the selection criteria for the actual indications and targets. The experience of different targets may be useful to guide and tailor the target choice to the individual clinical condition.

Deep Brain Stimulation Electrode Used for Radiofrequency Lesion of the Globus Pallidus Internus in Dystonia

Background: There have recently been increasing case reports in the literature of deep brain stimulation (DBS) electrodes used for lesioning with satisfactory clinical success in the treatment of Parkinson disease and tremor. Methods: After preliminary experiments of radiofrequency (RF) lesioning with a quadripolar DBS lead, a paediatric case of generalized primary dystonia was treated by RF lesioning of the globus pallidus internus (Gpi) with an electrode previously used for chronic stimulation. In order to study electrode damage related to the RF procedure, an electron microscopy study (SEM) at different magnifications (×40 and ×300) was performed. Results: Nine months after the unilateral pallidotomy, the patient had a good and stable control of dystonia. The MR study showed a T1-weighted hyperintensity signal corresponding to the electrode contacts used for lesions. The SEM scans of the DBS electrode used for RF lesioning did not show alterations of the ultrastructure. Conclusions: The RF lesioning technique by a DBS electrode allows small and staged lesions and could also be performed in a bilateral target. The versatility, efficacy, safety and low cost of the device make this approach suitable in selected cases.

Pallidotomy for medically refractory status dystonicus in childhood.

Status dystonicus is a rare and potentially fatal condition of continuous and generalized muscle contraction that can complicate dystonia. As status dystonicus is usually refractory to traditional pharmacological therapy, alternative and invasive strategies have been developed, but so far there are no guidelines on status dystonicus management. Pallidotomy has shown good results in status dystonicus treatment.

Vagus nerve stimulation in refractory epilepsy: New indications and outcome assessment

Although vagus nerve stimulation (VNS) is an effective alternative option for patients with refractory epilepsy unsuitable for conventional resective surgery, predictors of a better control of seizure frequency and severity are still unavailable. This prospective study reports on 39 patients, including 4 children affected by epilepsia partialis continua (EPC), who underwent VNS for refractory epilepsy. The overall seizure frequency outcome was classified into three groups according to reduction rate: ≥75%, ≥50%, and <50%. Engel and McHugh classifications were also used. The median follow-up period was 36months. A seizure reduction rate ≥50% or EPC improvement was observed in 74% of the patients. Twenty-one out of 35 cases (60%) resulted in Engel classes II and III. Outcome, as defined by the McHugh scale, showed a responder rate of 71%. These results suggest that younger patient age and focal or multifocal epilepsy are related to a better seizure control and cognitive outcome. Vagus nerve stimulation could also be considered as an effective procedure in severe conditions, such as drug-refractory EPC.

Secondary chronic cluster headache treated by posterior hypothalamic deep brain stimulation: First reported case

Introduction Deep brain stimulation (DBS) of the posterior hypothalamus (pHyp) has been reported as an effective treatment for primary, drug-refractory and chronic cluster headache (CCH). We here describe the use of such a procedure for the treatment of secondary CCH due to a neoplasm affecting the soft tissues of the right hemiface. Methods A 27-year-old man affected by infiltrating angiomyolipoma of the right hemiface who subsequently developed drug refractory homolateral CCH underwent DBS of the right pHyp region at the Fondazione IRCCS Istituto Nazionale Neurologico Carlo Besta. Results After surgery, the patient presented a significant reduction in frequency of pain bouts. However, because of a subsequent infection, the entire system was removed. After re-implantation of the system, successful outcome was observed at 2 years follow-up. Discussion This brief report shows the feasibility of pHyp DBS in secondary drug-refractory CCH syndromes; future reports are needed in order to confirm our positive result.

Targeting the brain: considerations in 332 consecutive patients treated by deep brain stimulation (DBS) for severe neurological diseases

Deep brain stimulation (DBS) extends the treatment of some severe neurological diseases beyond pharmacological and conservative therapy. Our experience extends the field of DBS beyond the treatment of Parkinson disease and dystonia, including several other diseases such as cluster headache and disruptive behavior. Since 1993, at the Istituto Nazionale Neurologico “Carlo Besta” in Milan, 580 deep brain electrodes were implanted in 332 patients. The DBS targets include Stn, GPi, Voa, Vop, Vim, CM–pf, pHyp, cZi, Nacc, IC, PPN, and Brodmann areas 24 and 25. Three hundred patients are still available for follow-up and therapeutic considerations. DBS gave a new therapeutic chance to these patients affected by severe neurological diseases and in some cases controlled life-threatening pathological conditions, which would otherwise result in the death of the patient such as in status dystonicus, status epilepticus and post-stroke hemiballismus. The balance of DBS in severe neurological disease is strongly positive even if further investigations and studies are needed to search for new applications and refine the selection criteria for the actual indications.

Vagus nerve stimulation for drug-resistant Epilepsia Partialis Continua: Report of four cases

BACKGROUND Vagus nerve stimulation (VNS) represents an adjunctive surgical option for adult and pediatric patients with drug-resistant epilepsy, who are not eligible for surgical resection or disconnection. However, little is known on its efficacy in the treatment of Epilepsia Partialis Continua (EPC), a rare but serious form of motor status epilepticus associated either with progressive or with non-evolving neurological diseases. PURPOSE AND METHODS To evaluate the effect of VNS in a series of four children affected by medically unresponsive EPC secondary to chronic inflammatory encephalopathy (two cases), Rasmussen encephalitis (one case) and poliodystrophy (one case). RESULTS After VNS implantation, the stimulation amplitude was progressively increased and, after a mean interval of 47 days, a partial reduction of EPC and associated focal seizures was observed in all patients. After a mean follow-up of three years, one child stopped EPC, two presented short and rare episodes and in one patient 2-3 residual seizures per day was reported. In all cases, reduction of epileptic activity was associated with mild improvement of motor and cognitive abilities. No serious side effects were reported. CONCLUSION VNS may be considered as an option for EPC when medical treatment fails and other more invasive neurosurgical options are not feasible.

Posteroventrolateral pallidotomy through implanted DBS electrodes monitored by recording local field potentials

This paper describes the use of globus pallidus internus (Gpi) local field potentials recorded through pre-implanted deep brain stimulation (DBS) electrodes on a patient affected by generalized dystonia. The recordings were made both before and after radiofrequency-induced posteroventrolateral bilateral stereotactic pallidotomy. LFP patterns and macroelectrode impedances were modified after the pallidotomy, along with the improvement of dystonic symptoms. After implantation, the DBS electrodes were used for subsequent bedside pallidotomies that were required by the evolution and/or persistence of symptoms. In our hands, LFPs were safe and effective in monitoring pallidotomy performed through DBS electrodes.

Acute intralesional recording in hypothalamic hamartoma: description of 4 cases

Hypothalamic hamartomas (HHs) are intrinsically epileptogenic lesions associated to medically intractable focal epilepsy mainly characterized by gelastic and focal seizures. Intralesional recording with deep electrodes has documented the presence of ictal discharge arising from inside the lesion. Nevertheless interictal and ictal scalp EEG is poorly informative and non-localizing in a great deal of cases. HH disconnection leads to seizure remission in most cases. To describe the intralesional EEG recordings and to compare them with concomitant scalp EEG and with previous cases reported in literature. We reviewed the medical records of 17 children affected by drug-resistant focal epilepsy associated to HH. We recorded intralesional electrical activity during stereo-endoscopic disconnection in three cases and during deep brain stimulation implantation in one. We also correlated it with the simultaneous scalp-EEG recording. Acute intralesional recordings in our cases confirmed the presence of epileptiform abnormalities intermingled with low-voltage activity, mostly on the same side of the HH attachment. Paroxysmal activity recorded inside the HH was always evident. Mapping of HH epileptogenic activity could be useful to confirm the usefulness of disconnection procedure. This should consider on-site recording from the HH and if abnormalities are detected safely proceed to disconnection of the HH.

Cosmetic Posterior Implant of Internal Pulse Generators in Deep Brain Stimulation Procedures: Technical Report

The study aims to describe a novel cosmetic implantation technique of internal pulse generators (IPGs) for deep brain stimulation (DBS) electrodes.