Comparison of microvascular decompression, percutaneous radiofrequency rhizotomy, and stereotactic radiosurgery in the treatment of trigeminal neuralgia: A long term quasi-experimental study.

BACKGROUND: Microvascular decompression (MVD), radiofrequency rhizotomy (RFR), and stereotactic radiosurgery (SRS) are surgical techniques frequently used in the treatment of idiopathic trigeminal neuralgia (TN), although the results reported for each of these are diverse. OBJECTIVE: This study aimed to compare long-term pain control obtained by MVD, SRS, and RFR in patients with idiopathic TN. METHODS: To compare the results obtained by MVD, SRS, and RFR we chose a quasi-experimental, ambispective design with control groups but no pretest. A total of 52 participants (MVD n = 33, RFR n = 10, SRS n = 9) were included. Using standardized outcome measures, pain intensity, pain relief, quality of life, and satisfaction with treatment were assessed by an independent investigator. The TREND statement for reporting non-randomized evaluations was applied. Clinical outcomes were evaluated at the initial postoperative period and at 6 months, 1, 2, 3, 4, and 5 years postoperatively. RESULTS: MVD has shown better results in pain scales compared to ablative procedures. Significant differences between groups were found regarding pain intensity and pain relief at the initial postoperative period (p < 0.001) and 6 months (p = 0.022), 1 year (p < 0.001), 2 years (p = 0.002), and 3 years (p = 0.004) after the intervention. Those differences exceeded the thresholds of the minimal clinically important difference. A higher percentage of patients free of pain was observed in the group of patients treated by MVD, with significant differences at the initial postoperative period (p < 0.001) and 6 months (p = 0.02), 1 year (p = 0.001), and 2 years (p = 0.04) after the procedure. Also, a higher risk of pain recurrence was observed in the RFR and SRS groups (HR 3.15, 95% CI 1.33-7.46; p = 0.009; and HR 4.26, 95% CI 1.77-10.2; p = 0.001, respectively) compared to the MVD group. No significant differences were found in terms of quality of life and satisfaction with treatment. A higher incidence of complications was observed in the MVD group. CONCLUSION: Concerning pain control and risk of pain recurrence, MVD is superior to RFR and SRS, but not in terms of quality of life, satisfaction with treatment, and safety profile.

Radiofrequency ablation of the centromedian thalamic nucleus in the treatment of drug-resistant epilepsy.

OBJECTIVE: To determine the usefulness and efficacy of radiofrequency ablations (RFA) of the Centromedian thalamic nucleus (CMN) to control primarily generalized or multifocal seizures in refractory epilepsy. METHODS: Six patients with clinical diagnosis of multifocal or primarily generalized drug-resistant epilepsy were included. Bilateral RFA of the CMN was performed through a monopolar 1.8 mm. tip electrode with a temperature of 80 °C during 90 seconds. Patients were followed in every 3 months visit for 20 to 36 months and kept a monthly seizure count calendar. We also compared maximal paroxysmal electroencephalogram (EEG) activity and neuropsychological evaluation pre and 6 months postoperatively. RESULTS: A significant reduction in the number of generalized seizures was observed in all subjects in the range of 79-98%, starting the first post-operative month. Although focal aware seizures remained unchanged throughout follow-up, there was an important reduction on paroxysmal activity between the pre and postoperative EEG. No major changes on cognitive status were detected. There was post-operative dysphagia and odynophagia lasting one week and there was no mortality in this group of patients. CONCLUSION: Preliminary results of CMN RFA suggest safety and a trend toward reduction of some seizure types, it may reduce the seizure frequency like other palliative procedures since the first post-operative month, but a larger, controlled study would be needed to establish the value of this therapy.

Hemifacial Spasm Associated with Compression of the Facial Colliculus by a Choroid Plexus Papilloma of the Fourth Ventricle.

BACKGROUND: Hemifacial spasm is an involuntary condition that involves muscles innervated by the ipsilateral facial nerve. There are secondary causes of hemifacial spasm that can produce a typical presentation of symptoms. Extrinsic compression of the facial colliculus at the floor of the fourth ventricle is responsible for <0.6% of the causes of secondary hemifacial spasm, as the cases with this origin reported in the literature are rare. CASE REPORTS: We present the case of a 43-year-old female with hemifacial spasm of typical characteristics 6 months after onset. Upon clinical examination, a severe contraction of the orbicularis oculi, orbicularis oris, and superficial muscles of the neck displaying 50 crisis per hour was revealed. Brain magnetic resonance imaging showed absence of the facial nerve vascular loop in the cisternal portion, with evidence of an intraventricular tumor in relation with the medial portion of the fourth ventricle at the facial colliculus level, indicating a secondary origin of hemifacial spasm. Preoperative electromyography demonstrated irritative electric activity in the muscular branches of the facial nerve. A telovelar approach was performed to the fourth ventricle with intraoperative electrophysiology monitoring, with immediate resolution of the irritative activity after complete tumor resection. The result of the histopathologic study was a choroid plexus papilloma. CONCLUSION: Fourth ventricle tumors with extrinsic compression of the facial colliculus represent <0.6% of the causes of hemifacial spasm. Its relationship with choroid plexuses papilloma is being described as the first case reported in the literature. Clinical correlation, imaging, and intraoperative findings in conjunction with intraoperative electrophysiology recordings allow to predict the resolution of symptoms after resecting the lesion.

Radiofrequency Ablation of Prelemniscal Radiations for the Treatment of Non-Parkinsonian Tremor.

OBJECTIVE: Previous reports proposed prelemniscal radiations (Raprl) as a target to treat motor symptoms of Parkinson's disease, and this was found particularly effective to control rest and postural tremor. However, tremor of other etiologies has been seldom treated with deep brain stimulation or ablation in this target. We present a series of such cases successfully treated by Raprl radiofrequency (RF) lesions. MATERIAL AND METHODS: Six patients with predominant unilateral tremor on the right arm: 4 intention, 1 cerebellar and 1 rubral tremor, incapacitating in spite of at least 2 regimes of medical treatment at maximal tolerated doses, were operated under local anesthesia. RF lesions were performed in Raprl contralateral to most prominent symptoms. Patients had monthly evaluation of tremor severity through the Fahn-Tolosa-Marin Tremor Rating Scale and disability through the Tremor Disability Scale along a 1-year follow-up. RESULTS: In 4/6 patients tremor was stopped by the simple insertion of an RF electrode in Raprl; in the other 2 cases, stimulation through the RF electrode at 100 Hz, with 100 µs and 1.0-1.5 V, stopped the tremor without side effects. Tremor disappeared in all cases immediately after surgery and partially reappeared in 2 cases with an amplitude about 20% of the preoperative condition. RF lesions in postoperative MRI ranked from 1.8 to 2.6 mm in diameter. CONCLUSIONS: RF lesioning in Raprl is a simple, highly effective, inexpensive way to treat tremor of different etiologies.

Prognostic factors of unilateral prelemniscal radiations radiofrequency lesions: A surgical technique for the treatment of Parkinson's disease motor symptoms.

OBJECTIVE: A group of patients with Parkinson's disease (PD) were managed with unilateral prelemniscal radiation radiofrequency lesions (U-Raprl). The current study aims to evaluate prognostic factors that could influence clinical response. METHODS: Patients previously diagnosed with PD managed with U-Raprl were included in the study, classifying them into two groups according to their percentage of clinical response ( 1.5), Age (p < 0.0001, ∆ = 2.38), Evolution (p < 0.0001, ∆ = 2.38), and post-operative UPDRS (p < 0.01, ∆ = 1.38). The qualitative analysis of the distribution regarding the responder group shows that those patients with an age under 58 years, an evolution fewer than 7 years, and a preoperative HYS score smaller than 2, showed a response ≥ 50% according to the UPDRS-III in all cases. CONCLUSION: U-Raprl is a highly effective procedure with a 5-year persistence of improvement. The most relevant prognostic factors to consider for a clinical response according to UPDRS-III greater than 50% are age under 58 years, less than 7 years of PD evolution, and HYS less or equal to 3.

Current concepts of pain pathways: a brief review of anatomy, physiology, and medical imaging.

BACKGROUND: Although the essential components of pain pathways have been identified, a thorough comprehension of the interactions necessary for creating focused treatments is still lacking. Such include more standardised methods for measuring pain in clinical and preclinical studies and more representative study populations. OBJECTIVE: This review describes the essential neuroanatomy and neurophysiology of pain nociception and its relation with currently available neuroimaging methods focused on health professionals responsible for treating pain. METHODS: Conduct a PubMed search of pain pathways using pain-related search terms, selecting the most relevant and updated information. RESULTS: Current reviews of pain highlight the importance of their study in different areas from the cellular level, pain types, neuronal plasticity, ascending, descending, and integration pathways to their clinical evaluation and neuroimaging. Advanced neuroimaging techniques such as fMRI, PET, and MEG are used to better understand the neural mechanisms underlying pain processing and identify potential targets for pain therapy. CONCLUSIONS: The study of pain pathways and neuroimaging methods allows physicians to evaluate and facilitate decision-making related to the pathologies that cause chronic pain. Some identifiable issues include a better understanding of the relationship between pain and mental health, developing more effective interventions for chronic pain's psychological and emotional aspects, and better integrating data from different neuroimaging modalities for the clinical efficacy of new pain therapies.

Minimally Invasive Retrosigmoidal Parasterional Burr-Hole Approach: Technique and Neuropathic Pain Amelioration after Microvascular Decompression of the Trigeminal Nerve.

BACKGROUND: Trigeminal neuralgia, a common condition in clinical practice, often occurs due to vascular compression caused by aberrant or ectopic arterial or venous vessels. Microvascular decompression through a minimally invasive retrosigmoidal approach has shown high rates of pain control, low complication rates, and excellent therapeutic results. OBJECTIVE: To describe the surgical technique and clinical outcomes in terms of pain relief after microvascular decompression of the trigeminal nerve through a minimally invasive retrosigmoidal parasterional burr-hole technique. METHODS: A group of patients with trigeminal neuralgia refractory to medical management who underwent microvascular decompression were examined. The records of the patients were considered retrospectively (2016-2018), and the outcomes were considered based on the Visual Analogue Scale (VAS) and the Barrow Neurological Institute Pain Scale (BNIPS) added to a technical note of the surgical technique for a minimally invasive retrosigmoidal parasterional burr-hole. RESULTS: Twenty-two patients were evaluated, and clinical assessment after surgical intervention showed a decrease in pain according to the VAS, resulting from an average preoperative state of 9.5 ± 0.37 to a postoperative condition of 1.32 ± 1.28, exhibiting statistically significant changes (p < 0.0001, d = 9.356). On the other hand, in relation to the BNIPS scale, a decrease from an average preoperative status of 4.55 ± 0.25 to a postoperative status at 12 months of 1.73 ± 0.54 was also demonstrated, showing significant changes (p < 0.0001, d = 3.960). CONCLUSION: Microvascular decompression of the trigeminal nerve through a minimally invasive retrosigmoidal parasterional burr-hole is feasible and can be a safe and effective technique for the management of pain. However, further research employing larger sample sizes and longer follow-up periods is necessary.

Optimizing deep brain stimulation for the treatment of drug-resistant temporal lobe epilepsy: a pilot study.

OBJECTIVE: The authors sought to determine the antiseizure effects of deep brain stimulation (DBS) of the parahippocampal cortex (PHC) for treatment of drug-resistant mesial temporal lobe epilepsy (MTLE). METHODS: After a 3-month baseline period, 6 adult patients with drug-resistant MTLE and hippocampal sclerosis (HS) had stereoelectroencephalography (SEEG)-DBS electrodes implanted at the PHC for identification of the seizure onset zone (SOZ). Patients entered an 8-month, randomized, double-blind protocol for DBS, followed by a 12-month open-phase study. Monthly reports of seizure frequency were collected, with separate counting of focal seizures with or without awareness impairment (focal impaired awareness seizures [FIAS] or focal aware seizures [FAS], respectively) and focal evolving to bilateral generalized tonic clonic seizures (GTCS). Stimulation parameters were 130 Hz, 450 µsec, 2.5-3 V, and cyclic stimulation 1 minute on/4 minutes off. RESULTS: The total seizure rate decrement during follow-up was 41% (CI 25%-56%), with better seizure control for GTCS (IQR 19%-20%) and FIAS (IQR 0%-16%), with FAS being less responsive (IQR 67%-236%). No neuropsychological deterioration was observed. CONCLUSIONS: PHC DBS induced important antiseizure effects in patients with incapacitating FIAS and GTCS, most likely through blocking the propagation of hippocampal-onset seizures. The PHC target can be easily and safely approached due to positioning away from vascular structures, and there was no evidence of DBS-induced cognitive deterioration.

Prelemniscal Radiations as a Target for the Treatment of Parkinson Disease - Individual Variations in the Stereotactic Location of Fiber Components: A Probabilistic Tractography Study.

OBJECTIVE: Prelemniscal radiation (Raprl) lesions and deep brain stimulation effectively control motor symptoms of Parkinson disease, but individual variations in the stereotactic location of its fiber components constitute a significant concern. The objective of this study was to determine individual variations in the stereotactic location of fiber tracts composing Raprl. METHODS: Raprl fiber composition was determined in a group of 10 Parkinson patients and 10 matched controls using 3T magnetic resonance imaging, brain imaging processed for diffusion-weighted images, tract density imaging, and constrained spherical deconvolution. The stereotactic position of the point of maximal proximity (PMP), which is the point where the most significant number of fibers is concentrated in the smallest volume in the tractography, was evaluated in the right and left hemispheres of the same person, between individuals and between patients and controls for each tract in coordinates "x," "y," and "z." The stereotactic coordinates at which PMP of all tracts meet were statistically determined, representing the recommended aim for this target. RESULTS: Stereotactic coordinates of the 3 fiber tracts composing Raprl, cerebellar-thalamic-cortical, globus pallidus-peduncle-pontine nucleus, and mesencephalic-orbital frontal cortex, did not vary between right and left hemispheres in the same person and between patients and controls. In contrast, PMP variability between individuals was significant, mainly for the mesencephalic-orbitofrontal tract. Therefore, probabilistic tractography can better determine individual variations to plan electrode trajectories. CONCLUSIONS: Individual PMP variations for fiber tracts in Raprl, identified by probabilistic tractography, provide a platform for planning the stereotactic approach to conform volumes for deep brain stimulation and lesions.

Olfactory function in patients with temporal lobe epilepsy; correlation of functional magnetic resonance imaging for olfaction with the laterality of the epileptic focus.

The olfactory function shares the same cerebral structures as those involved in the origin and propagation of focal temporal lobe seizures. Likewise, functional magnetic resonance imaging (fMRI) allows the study of olfactory function. This suggests that by quantitatively studying the olfactory function with an olfactory paradigm through fMRI it is possible to identify the functional alteration produced by the epileptic focus. The objective of the present study was to assess the olfactory function in the side of the epileptic focus in patients with mesial temporal lobe epilepsy, using fMRI for smell, and propose a non-invasive diagnostic method for patients candidates to mesial temporal lobe epilepsy surgery. METHODS: Patients (n = 18) with clinical diagnosis of mesial temporal lobe epilepsy, refractory to pharmacological treatment: 7 patients (38.9%) with non-invasive studies consistent enough to submit them to anterior temporal lobectomy, and 11 (61.1%) patients where focal onset seizures were identified by stereoelectroencephalography (SEEG) on the left temporal lobe in 5 (27.8%) and in both temporal lobes in 2 (11.1%). Patients were evaluated using EEG, MRI, neuropsychological data, and fMRI with olfactory paradigm. Results of the fMRI were compared with the laterality of the epileptic focus determined by intracranial electroencephalogram recordings through stereotactically placed electrodes, and with post-surgical outcome at one year of follow-up. RESULTS: fMRI showed a lower olfactory activation in 81.8% concordant with unilateral onset seizures. There were significant differences of olfactory fMRI activation between epileptic and non-epileptic foci. CONCLUSION: Functional magnetic resonance imaging with an olfactory paradigm may be a non-invasive diagnostic tool to determine the laterality of seizure onset in the mesial temporal lobe.

Specific movement and disability improvements in Burke-Fahn-Marsden Dystonia Rating Scale derived from pallidotomy in refractory patients to medical treatment.

BACKGROUND: Dystonia is a movement disorder associated with significant disability and is usually refractory to medical treatment. Pallidotomy may decrease dystonic movements. The aim of this study was to quantify movement and disability improvements through Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). METHODS: We carried out a longitudinal clinical study in patients with refractory primary and secondary dystonia, who underwent radiofrequency (RF) unilateral and bilateral lesions on the postero-ventro-lateral globus pallidus internus (GPi), evaluating the outcomes through BFMDRS and variables as age, time of evolution, etiology, body distribution, planned target coordinates, and lesion size, during a mean follow-up time of 35.67 months. RESULTS: Nine RF pallidotomies were performed on 6 patients, 7 right-sided and 2 left-sided; three patients were treated unilaterally for one occasion, while the others underwent 2 surgeries, including one staged bilateral procedure. Mean BFMDRS scores for movement were 38.5 preoperative and 25.5 postoperative, and for disability were 20.4 preoperative and 17.3 postoperative. We noticed improvement in movement (32.54%, p = 0.001) and disability (17.23%, p = 0.002). There was one right GPi and internal capsule (IC) infarction with contralateral hemiparesis as sequelae. CONCLUSIONS: RF pallidotomy is an effective and accessible procedure to reduce BFMDRS scores in refractory dystonia if patients are correctly selected by severity, evolution, and disability as determining factors.

Women in Neurosurgery: First Neurosurgeon in Latin America and Current Mexican Leaders.

BACKGROUND: History has taught us that Mexican culture has been largely supported by women, despite gender prejudice from the society. Neurosurgery has not been the exception. Therefore, we investigated the challenges and influence of female neurosurgeons in Mexico. METHODS: We conducted a review of the literature and an analysis of the internal database of the Mexican Society of Neurological Surgery focusing on 3 topics: 1) the historical presence of women and gender inequality in Mexico; 2) the life and legacy of the woman who became the first neurosurgeon in Mexico and in Latin America; and 3) the participation of women in neurosurgery in the past 3 decades. RESULTS: In Latin America, the first woman in neurosurgery was María Cristina García-Sancho, who completed her neurosurgical training in 1951. Currently, women represent 6.2% of the total members of the Mexican Society of Neurological Surgery (MSNS). This percentage is still low, although data collected in this study suggest that it might increase in the next few years because 16.7% of Board Directors of the MSNS are women, the next elected president is a female neurosurgeon, and 14.5% of neurosurgery residents are women. CONCLUSIONS: Although a steady increase has occurred of women in neurosurgery in Mexico, there is still work to do, especially to overcome the barriers related to the old assumptions of the cultural and social roles of women.

Dysembryoplastic neuroepithelial tumor and temporal arachnoid cyst on a child with epilepsy. Which one to operate? Case report and literature review.

A 6 year-old male, with seizures characterized by abnormal epigastric sensation, behavioral arrest, upper extremities search automatisms and secondary tonic-clonic generalization. Magnetic resonance imaging showed a hypointense cystic extra-axial image with an increase in the thickness of the convolutions in the first and second gyri of the right frontal lobe. It was decided to resect the frontal lesion with transoperative motor mapping. Morphological and immunohistochemical findings corresponded to dysembryoplastic neuroepithelial tumor with focal cortical dysplasia. Adequate semiology, analysis of the electroencephalogram, and imaging studies allowed treating adequately the cortical dysplasia. At present, the patient is seizure-free without medication (Engel IA).

Niño de 6 años con crisis caracterizadas por sensación epigástrica, arresto conductual, automatismos de búsqueda y generalización tónico-clónica secundaria. La resonancia magnética mostró una imagen extraaxial quística y un aumento del grosor de las circunvoluciones del primer y segundo giros del lóbulo frontal derecho. Se decidió resecar primero la lesión frontal con guía por mapeo transcortical intraoperatorio. Los hallazgos morfológicos e inmunohistoquímicos mostraron un tumor neuroepitelial disembrioplásico con displasia cortical focal. La semiología, el análisis del electroencefalograma y la imagen permitieron orientar el tratamiento. Actualmente el paciente está libre de crisis y sin medicamentos (Engel IA).

Long-Term Improvement of Parkinson Disease Motor Symptoms Derived From Lesions of Prelemniscal Fiber Tract Components.

BACKGROUND: Prelemniscal radiations (Raprl) are composed of different fiber tracts, connecting the brain stem and cerebellum with basal ganglia and cerebral cortex. In Parkinson disease (PD), lesions in Raprl induce improvement of tremor, rigidity, and bradykinesia in some patients, while others show improvement of only 1 or 2 symptoms, suggesting different fiber tracts mediate different symptoms. OBJECTIVE: To search for correlations between improvements of specific symptoms with surgical lesions of specific fiber tract components of Raprl in patients with PD. METHODS: A total of 10 patients were treated with unilateral radiofrequency lesions directed to Raprl. The improvement for tremor, rigidity, bradykinesia, posture, and gait was evaluated at 24 to 33 mo after operation through the Unified Parkinson's Disease Rating Scale (UPDRS) score, and the precise location and extension of lesions through structural magnetic resonance imaging and probabilistic tractography at 6 to 8 mo postsurgery. Correlation between percentage of fiber tract involvement and percentage of UPDRS-III score improvement was evaluated through Spearman's correlation coefficient. RESULTS: Group average improvement was 86% for tremor, 62% for rigidity, 56% for bradykinesia, and 45% for gait and posture. Improvement in global UPDRS score correlated with extent of lesions in fibers connecting with contralateral cerebellar cortex and improvement of posture and gait with fibers connecting with contralateral deep cerebellar nuclei. Lesion of fibers connecting the globus pallidum with pedunculopontine nucleus induced improvement of gait and posture over other symptoms. CONCLUSION: Partial lesion of Raprl fibers resulted in symptom improvement at 2-yr follow-up. Lesions of selective fiber components may result in selective improvement of specific symptoms.

Anatomic characterization of prelemniscal radiations by probabilistic tractography: implications in Parkinson's disease.

To characterize the anatomical connectivity of the prelemniscal radiations (Raprl), a white matter region within the posterior subthalamic area (PSA) that is an effective neurosurgical target for treating motor symptoms of Parkinson's disease (PD). Diffusion-weighted images were acquired from twelve healthy subjects using a 3T scanner. Constrained spherical deconvolution, a method that allows the distinction of crossing fibers within a voxel, was used to compute track-density images with sufficient resolution to accurately delineate distinct PSA regions and probabilistic tractography of Raprl in both hemispheres. Raprl connectivity was reproducible across all subjects and showed fibers traversing through this region towards primary and supplementary motor cortices, the orbitofrontal cortex, ventrolateral thalamus, and the globus pallidus, cerebellum and dorsal brainstem. All brain regions reached by Raprl fibers are part of motor circuits involved in the pathophysiology of PD; while these fiber systems converge at the level of the PSA, they can be spatially segregated. Fibers of distinct and specific motor control networks are identified within Raprl. The description of this anatomical crossroad suggests that, in the future, tractography could allow deep brain stimulation or lesional therapies in white matter targets according to individual patient's symptoms.

Evaluation of bilateral cingulotomy and anterior capsulotomy for the treatment of aggressive behavior.

BACKGROUND: Agressiveness is a psychiatric symptom that may be part of schizophrenia, mental retardation, drug abuse and other conditions. Surgical treatment remains controversial and few therapeutic options are available. We undertook this study to perform a prospective analysis on the efficacy and safety of bilateral cingulotomy and anterior capsulotomy in the treatment of aggressiveness behavior. METHODS: We studied 25 patients with a primary diagnosis of aggressiveness refractory to conventional treatment. Subjects were clinically evaluated with the Mayo-Portland adaptability inventory and the Global Assessment of Functioning score. Lesions were placed stereotactically in both targets and confirmed by postoperative magnetic resonance imaging. Significant changes were evaluated with Wilcoxon test after 3 and 6 months. RESULTS: According to inclusion and exclusion criteria, only 12 patients were finally included and surgical treated. Lesions significantly decreased using the Mayo-Portland adaptability inventory and the Global Assessment of Functioning score (p <0.002) at 3 and 6 months follow-up. Only five patients showed either mild or transitory postsurgical complications. CONCLUSIONS: Combined bilateral anterior capsulotomy and cingulotomy successfully reduced aggressiveness behavior and improved clinical evaluations. These effects were obtained with fewer complications than previously described targets.

Preliminary study in patients with obsessive-compulsive disorder treated with electrical stimulation in the inferior thalamic peduncle.

OBJECTIVE: Deep brain stimulation has been used in the treatment of refractory obsessive-compulsive disorder (OCD). Our principal objective was to determine the safety and effectiveness of deep brain stimulation of the inferior thalamic peduncle in the treatment of refractory OCD. METHODS: An open protocol was performed from March 2003 to April 2007 in 5 patients with OCD refractory to conventional treatments. Bilateral stereotactic implantation of tetrapolar electrodes was aimed at the inferior thalamic peduncle and corroborated by electrophysiological responses and magnetic resonance imaging. All patients were off stimulation for 1 month after implantation. In the on-stimulation period, parameters were set at 5 V, 450 microseconds, 130 Hz in bipolar and continuous mode. Clinical changes were evaluated every 3 months for 12 months by means of the Yale-Brown Obsessive Compulsive Scale and the Global Assessment of Functioning scale. Statistical significance was assessed by the Friedman and Wilcoxon tests. RESULTS: The mean Yale-Brown Obsessive Compulsive Scale score decreased from 35 to 17.8 (P < 0.001), and the mean Global Assessment of Functioning scale score improved from 20% to 70% (P < 0.0001). The neuropsychological battery did not show significant changes, and there were no side effects related to electrical stimulation in the chronic period. CONCLUSION: We conclude that inferior thalamic peduncle stimulation is a safe procedure and may be an effective alternative in the treatment of those OCD cases refractory to conventional treatments.

La corteza y la neurocirugía para el tratamiento de trastornos psiquiátricos / Cerebral cortex and neurosurgery for the tratement of psychiatric disorders

En 1878 Brocca llamó el gran lóbulo límbico a las áreas corticales que rodeaban en forma de anillo al cuerpo calloso. Esto incluía el giro cingulado , el giro esplénico, el hipocampo y la amígdala del lóbulo temporal (áreas 23, 24, 25, 26, 27, 28, 32 y 34)...

La neurocirugía en los trastornos de la alimentación: ¿una alternativa posible?

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Abstract: Composition and quantity of food in-taken varies considerably between one meal and another, or between one day and the following. Non biological factors -such as emotional, social, day time, feasibility in the type of food, and cost- are, among others, factors that in some way affect the degree of energy in-take by food, which generally is not related with daily energy expenditure. These phenomena represent an active process of regulation that is characterized by the balance between signs that stimulate hunger, called orexigenics and those that produce satiation to stop in-take, called anorexigenics, that promotes the stability in the quantity of corporal energy manifested as fat. In this feeding regulatory process there are many molecular signs that participate and regulate the in-take of behaviour food for homeostasis. There are two hypothalamic centers related with the food in-take control: the hunger centre in the lateral hypothalamus and the satiation centre in the ventromedial nucleus. In this control many impulses participate, regulated by substances called neurotransmitters, such as: neuropeptide Y, galanine, orexines for the hunger centre and nor epinephrine, serotonin, and dopamine for the satiation centre. Insulin reaches the brain through circulation and acts reducing the contribution of energy, it was the first hormonal sign that was implicated in weight control by CNS. The second identified hormone, secreted by the adiposity, was leptin. Both hormones circulate in levels proportional to the corporal fat and get to the CNS in proportion to its plasmatic concentrations. Receptors as leptin and insulin are expressed by brain neurons involved in the contribution of energy, and the administration of any of both peptides directly to the brain, reduce the in-take of food. The lack of any of these hormones produces the opposite. Leptin has a more important role than insulin in the control of the energetic homeostasis in the CNS. For example, the lack of leptin causes severe obesity with hyperfagia that persists regardless the levels of elevated insulin. In contrast, obesity isn't induced by the lack of insulin. Insulin has a critic role to promote the storage of fat and the synthesis of leptin through the fat cellule. The neuropeptide Y, produced in the arcuate nucleus of the hypothalamus has an anabolic effect. The gene of expression and secretion of this peptide in the hypothalamus increases during depletion, in the storage of corporal fat and/or when the signs of leptin/insulin are decreased in the brain. Leptin inhibits the gene of expression of the neuropeptide Y in the arcuate nucleus and the genetic "knockout" of the NPY reduces hyperfagia and obesity in mice ob/ob, indicating that the total response to the lack of leptin requires the signs of the NPY. Other substances like the Agouti protein (AGRP), the orexines (hypocretines A and B) and the concentrations of the melancortin hormone have been added to the molecule candidate list with anabolic effects. Also in the adjoining neurons of the arcuate nucleus, are originated anorexigenic peptides like alfa-MSH (a derivated of the pro-opiomelancortin, POMC) and CART (transcript protein related with cocaine and amphetamine). Both types of neurons (NPY/AGRP and POMC/CART) coexpress the leptin receptors. In those situations in which the levels of leptin or insulin are low, the NPY/AGRP neurons activate and the POMC/CART are inhibited. This suggests that the main site of adiposity signs transformation is a neuronal response in the arched nucleus. The link between the lateral hypothalamus and the elevated centers of the brain that regulate hunger and satiation is a very important aspect of the regulation system. There have been typified two types of neuropeptides linked to neurons, that appear to be exclusively of the lateral hypothalamus area: the concentrated melanin hormone (MCH) and the orexines. At the lateral zone, there have been specified two types of hypothalamic neuropeptides, the orexines A and B, also known as hypocretines 1 and 2, which are cellular bodies of the hypothalamus, especially at the lateral hypothalamus and the perifornical area, which stimulate the appetite in an independent way to other neuropeptides known. On the other hand, the orexines A and B derive (by proteolysis) of a common precursor, and are capable of activating their two respective receptors that work in conjunction with proteins G. The central administration of orexines stimulates the in-take and production of orexines' increase with fasting. These neuropeptides match with the hypocretines described by other authors, with expression in late ral hypothalamus, arched nucleus, septal nucleus and forebrain. Monoaminergic neurotransmitters. Noradrenalin Noradrenalin is synthesized in different areas of the brain such as the dorsal nucleus of the vague and the locus coeruleus.Noradrenalin shares the same place with NPY and the injection of both inside the preventricular nucleus increase the in-take of food. The repeated injection can result in weight increase; leptin can inhibit noradrenalin secretion. Dopamine Critic dependence of the in-take of food in the CNS is given by the dopamine sign, which is implicated in the voluntary lack of the food in-take. Motor alterations associated with the lack of dopamine affect also the alimentary behavior. The dopamine effect over the alimentary behavior varies depending of the studyied area. For example the routes of dopamine in the mesolimbic area contribute to the reward of the in-take of savory food. SerotoninThe 5HT2c receptor of serotonin is implicated in the decrease of the in-take of food and the weight increase, due to its effect in the impulse of the satiation centre. To maintain the homeostasis of normal energy it is necessary that the serotonin sign be intact. New alternative hypothesis. On one hand, the knowledge of regulation of the appetite-satiety neuroendocrine cycle, and on the other, the new techniques of neuromodulation through stereotaxic surgery, allow to offer an extraordinarily interesting field of research in certain patients with feeding disorders of difficult control and with an increase in the mortality risk. The alternative of controlling specific centers of hunger/satiation regulation, is still a hypothesis, though there are some data that allow us to assume that it could be feasible and we will mention them after. Current experience. Stereotaxic (Latin: stereo, three-dimensional; taxis, positioning) is a modern technique of neurosurgery that allows the localization and precise access to intra-cerebral structures, through a small orifice in the skull. If we have identified the places that regulate the intake of food or satiety, it is feasible that through this technique we can stimulate or inhibit this function and offer the patient an alternative that in theory could be feasible. Some of its possible advantages will be that we are talking about a minimum invasive surgery, generally performed using local anesthesia; patients need a minimum hospitalization stay and surgical risks are minimized. This allows us to predict in the majority of the patients a satisfactory evolution of weight decrease. The current experience of stereotaxic used in eating disorders is null; everything about it is hypothetic. However, the use of this proceeding for other accepted indications where there is previous experience, has allowed us to obtain interesting data of the evolution of these patients that shows indirectly, that the procedure has influenced in the corporal weight. We present these indirect results, which motivate us to continue considering its possible use in patients that show the approved profile according to an ethic committee properly authorized. In depression or bipolar disorder cases, the use of the stereotaxic surgery applying electrodes in the bottom pedunculo thalamic region (ITP), independently that they show an improve in their basal alteration, the patients show a weight increase, inferring a relationship of this area and the one of the hypothalamus for the appetite/satiation control, situation that hypothetically could benefit patients with anorexia nervosa or bulimia. In the cases with Parkinson Disease, the stereotaxic procedure has been made in the pre-lemniscal (RAPRL) or the subtalamic region (STN) in a unilateral or bilateral way, and although the response hasn't been uniform, the weight changes showed a decrease, making this a possible alternative to be used in some patients with morbid obesity according to the inclusion criteria. Final comments. The expectative of stereotaxic surgery in handling patients with difficult to control feeding disorders or with high risk of morbid-mortality, is shown as an hypothesis, that should consider the specific rules of good clinical practices and adjust to the rules of an approved ethics committee, for these procedures.

Introducción a la neurocirugía psiquiátrica

Resumen: La neurocirugía para tratar los trastornos psiquiátricos tiene sus primeros antecedentes modernos a mediados del siglo XIX con los trabajos de Buckhart, quien resecó parcialmente la corteza frontal de pacientes psiquiátricos. Aunque los resultados fueron alentadores en cuatro de seis casos, la muerte de uno y crisis convulsivas en otros dos frenaron el desarrollo de este procedimiento. En 1936, Egas Moniz y Almeida Lima efectuaron una sección de las fibras frontales en pacientes psiquiátricos con diversos diagnósticos, procedimiento que denominaron lobotomía prefrontal. El éxito de este tratamiento llevó a Moniz a obtener un premio Nobel en 1949. A su vez, esto alentó a Fulton y a Jacobsen a promover este tipo de procedimientos, denominados entonces "psicocirugía", en Estados Unidos. Desafortunadamente, la ausencia de un entendimiento adecuado de la fisiopatología y la sobreindicación de los procedimientos provocó que entre 1935 y 1950 se operaran alrededor de 20,000 pacientes en condiciones cuestionables y con importantes complicaciones. La aparición de los fármacos antipsicóticos y la falta de regulación y entendimiento de la neurocirugía psiquiátrica evitan nuevamente que este tratamiento se realice de manera científica y controlada. Aun así, Spiegel y Wacis iniciaron en 1946 la era de la neurocirugía estereotáctica que reduce el riesgo de complicaciones de la neurocirugía funcional. Cuatro procedimientos fueron aceptados entonces por la OMS para el tratamiento seguro y efectivo de enfermedades psiquiátricas. Estas cirugías incluyen la cingulotomía, la capsulotomía anterior, la tractotomía subcaudada y la leucotomía límbica (combinación de cingulotomía y tractotomía). Por otro lado, los trastornos psiquiátricos que han mostrado mejoría sustancial después de alguno de estos procedimientos neuroquirúrgicos son el trastorno depresivo mayor, el trastorno obsesivo-compulsivo, el trastorno bipolar, algunos trastornos de ansiedad, la adicción a sustancias y los trastornos impulsivos-agresivos. Es importante señalar que los criterios de inclusión a protocolos neuroquirúrgicos asistenciales o de investigación para mejorar los síntomas psiquiátricos han sido bien establecidos, y la selección de pacientes y los grupos neuroquirúrgicos deben ser supervisados por un comité de ética bien acreditado. Actualmente, las indicaciones para proponer como candidato a neurocirugía a un paciente son: Una enfermedad psiquiátrica diagnosticada de acuerdo con los criterios del DSM IV-R; evidencia de refractariedad (mejoría inferior a 50% de los síntomas) con los tratamientos convencionales; ésta debe ser avalada por dos psiquiatras. El padecimiento debe tener una duración de al menos cinco años. Además, un comité ético revisor de los protocolos quirúrgicos y de investigación debe evaluar a cada candidato al procedimiento o protocolo y cerciorarse de que el paciente o las personas responsables de él entiendan los criterios médicos y psiquiátricos para participar en el proceso; el comité supervisa también el proceso de consentimiento. Los procedimientos neuroquirúrgicos sólo podrán ser indicados en pacientes psiquiátricos con capacidad y ellos mismos aprobarán y firmarán un consentimiento informado. Las clínicas de neurocirugía psiquiátrica deberán trabajar estrechamente y contar con los siguientes especialistas: Un equipo de neurocirujanos estereotácticos con experiencia probada en neurocirugía psiquiátrica, neuromodulación, radiocirugía e investigación. Un equipo de psiquiatras con amplia experiencia en condiciones psiquiátricas y de investigación. Preferiblemente, ambos grupos deberán tener experiencia en neurocirugía psiquiátrica o contar con la asesoría de una clínica de neurocirugía psiquiátrica. La neurocirugía psiquiátrica deberá realizarse sólo para restaurar la función normal y aliviar al paciente de su angustia y sufrimiento. Los procedimientos deberán practicarse para mejorar la vida de los pacientes y nunca por motivos políticos, cuestiones legales o propósitos sociales. Finalmente, la neuromodulación ha demostrado ser una técnica útil y segura para el alivio de trastornos psiquiátricos debido a que sus efectos son reversibles y ajustables a cada paciente. Por lo mismo, en la actualidad se ha aplicado con éxito en el tratamiento de la depresión mayor, el trastorno obsesivo compulsivo y la enfermedad de Gilles de la Tourette.

Abstract: Recent background in neurosurgery for psychiatric disorders can be placed in the mid XIXth century. Buckhartd made partial resection of frontal cortex in 6 psychiatric patients, with successful results in 4 of them, but important side effects prevented the development of this scientific approach. In 1936 Egas Moniz and Almeida Lima performed a new neuro-psychiatric technique for treatment of several psychiatric disorders, named prefrontal lobotomy. Results of this treatment won Moniz a Nobel Prize in 1949, and encouraged Freeman and Watts to further develop this kind of surgery in United States of America. Unfortunately, the knowledge about pathophysiology was not sufficient to make a precise indication of surgery in this patients. Between 1935 and 1950, nearly 20,000 surgeries were performed in doubtful conditions, showing important side effects. On the other hand, the emergency of new drugs for the treatment of psychiatric disorders along with the absence of regulation stopped development of "psychosurgery". However, in 1946 Spiegel and Wacis started stereotactic age of neurosurgery, thus reducing risk and complication of this procedures. Nowadays, World Health Organization accepted four neurosurgery procedures for psychiatric disorders: cingulotomy, anterior capsulotomy, subcaudate tractotomy and limbic leucotomy (a combination of cingulotomy and subcaudate tractotomy). Best results for this kind of surgery are shown for affective disorders (major depression disorder, bipolar disorder, anxiety disorders) and obsessive compulsive disorder. Besides, in clinical research protocols the inclusion criteria for neurosurgical procedures in psychiatry have been well defined. Both patients' selection and medical team must be monitored by ethics committee. Currently, the requirements to consider a patient as a candidate for psychiatric neurosurgery are: Clear psychiatric diagnosis in accordance to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM.IV-TR). Evidence of refractivity (improved of symptoms inferior to 50%) to conventional treatments provided by two different psychiatrists. A minimum of 5 years of evolution in symptoms. The ethics committee must monitor surgical and research protocols in a case by case basis. The Committee will made sure that patient and relatives understand medic and psychiatric inclusion criteria. Neurosurgical procedures will only be indicated when the patient is able to understand and accept any details presented to him or her in a formal Consent Form. Neurosurgery psychiatric clinical teams should be integrated by: Stereotactic neurosurgeons whose have experience in psychiatric neurosurgery, neuromodulation, radiosurgery and clinical issues. A psychiatric team with ample experience in psychiatric conditions and research protocols. In case both teams of specialists are not experienced enough in the field of psychiatric neurosurgery, they must look for technical advice from other neurosurgical psychiatric centers. Psychiatric neurosurgery can only be performed to recover healthy conditions and relief suffering. These interventions must always be performed with the sole objective of improving patients quality of life and they must never be used for political, legal or social purposes. Finally, Neuromodulation has shown to be a useful and safe tool in relief of psychiatric disorders. Neuromodulation's effects are reversible and they can adjusted to patient. Nowadays, Neuromodulation is being used in patients with major depression, obsessive compulsive disorder and Tourette's illness.