An expandable chamber for safe brain retraction: new technologies in the field of transcranial endoscopic surgery / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Neurosurgery is a highly specialized field: it often involves surgical manipulation of noble structures and cerebral retraction is frequently necessary to reach deep-seated brain lesions. There are still no reliable methods preventing possible retraction complications. The objective of this study was to design work chambers well suited for transcranial endoscopic surgery while providing safe retraction of the surrounding brain tissue. The chamber is designed to be inserted close to the intracranial point of interest; once it is best placed it can be opened. This should guarantee an appreciable workspace similar to that of current neurosurgical procedures. The experimental aspect of this study involved the use of a force sensor to evaluate the pressures exerted on the brain tissue during the retraction phase. Following pterional craniotomy, pressure measurements were made during retraction with the use of a conventional metal spatula with different inclinations. Note that, although the force values necessary for retraction and exerted on the spatula by the neurosurgeon are the same, the local pressure exerted on the parenchyma at the edge of the spatula at different inclinations varied greatly. A new method of cerebral retraction using a chamber retractor (CR) has been designed to avoid any type of complication due to spatula edge overpressures and to maintain acceptable pressure values exerted on the parenchyma.

Localization of epileptogenic zone based on reconstruction of dynamical epileptic network and virtual resection / 生物医学工程学杂志

Drug-refractory epilepsy (DRE) may be treated by surgical intervention. Intracranial EEG has been widely used to localize the epileptogenic zone (EZ). Most studies of epileptic network focus on the features of EZ nodes, such as centrality and degrees. It is difficult to apply those features to the treatment of individual patients. In this study, we proposed a spatial neighbor expansion approach for EZ localization based on a neural computational model and epileptic network reconstruction. The virtual resection method was also used to validate the effectiveness of our approach. The electrocorticography (ECoG) data from 11 patients with DRE were analyzed in this study. Both interictal data and surgical resection regions were used. The results showed that the rate of consistency between the localized regions and the surgical resections in patients with good outcomes was higher than that in patients with poor outcomes. The average deviation distance of the localized region for patients with good outcomes and poor outcomes were 15 mm and 36 mm, respectively. Outcome prediction showed that the patients with poor outcomes could be improved when the brain regions localized by the proposed approach were treated. This study provides a quantitative analysis tool for patient-specific measures for potential surgical treatment of epilepsy.

Neurosurgical Treatment for Drug Addiction: Systematic Review

Substance-related disorders are psychiatric conditions that have a worldwide impact. Their multifactorial cycle has been treated pharmacologically and with therapeutic support. However, high refractoriness rates and difficulty to control relapses are among the pitfalls associated with these disorders. Thus, recent studies have shown that deep brain stimulation (DBS) is a promising treatment, with a direct intervention in the neurocircuitry of addiction. The results of the present systematic review of the use of DBS for the treatment of drug addiction show that this surgical procedure can reduce the desire for the drug, and, in some cases, establish abstinence, improve psychiatric symptoms related to mood and quality of life, and reintroduce the patient into the social and family environments. Nevertheless, this approach is still limited to the academic realm, based mainly on case reports, with ethics and therapeutic protocols still to be defined. Further in-depth scientific investigations are required to recommend its clinical application.

Intraventricular pneumocephalus associated with nasocephalic necrosis in a puppy: a case report / Pneumoencéfalo intraventricular associado à área de necrose nasoencefálica em filhote canino: relato de caso

Pneumocephalus is defined as the presence of air in any of the intracranial compartments. Its most frequent causes are trauma and cranial surgery. Clinical signs occur as a result of increased intracranial pressure and vary with the location and extent of the lesion. A case involving a seven-month-old female Saint Bernard, who suffered cranial trauma caused by a bite to the face at ten days of age and had presented with seizures and localized pain four months previously is reported. A computed tomography scan of the skull revealed a nasocephalic mass with low contrast enhancement, bone lysis, and hypodensity (-940 Hounsfield units) of the lateral and third ventricles, indicating intraventricular pneumocephalus. During surgery, a fragment of the mass was collected for histopathological examination, which demonstrated the presence of multifocal areas of necrosis. The computed tomography (CT) is a reliable method for the characterization of intracranial lesions and diagnosis of pneumocephalus, whose occurrence must be considered in pathological processes in which there is increased intracranial pressure and in patients undergoing certain surgical procedures and anesthetic specific, and CT is indicated as a monitoring tool for these patients.

Pneumoencéfalo é definido como a presença de gás em quaisquer dos compartimentos intracranianos e possui como causas mais frequentes o traumatismo e cirurgias cranianas. Os sinais clínicos ocorrem como consequência do aumento de pressão intracraniana e variam conforme o local e a extensão da lesão. Relata-se o caso de uma cadela de sete meses de idade, da raça São Bernardo, que sofreu trauma por mordedura em face, quatro meses antes, apresentando crises convulsivas e sensibilidade dolorosa local desde então. O exame tomográfico do crânio revelou massa nasoencefálica com baixa captação de contraste, lise óssea e hipodensidade (-940HU) dos ventrículos laterais e terceiro ventrículo encefálico, caracterizando pneumoencéfalo intraventricular. Foi realizada intervenção cirúrgica e coleta de fragmento da massa para exame histopatológico, que demonstrou existência de necrose multifocal. O exame de tomografia computadorizada (TC) é um método confiável para a caracterização de lesões intracranianas e diagnóstico de pneumoencéfalo, cuja ocorrência deve ser considerada em processos patológicos nos quais há aumento da pressão intracraniana e em pacientes submetidos a alguns procedimentos cirúrgicos e anestésicos específicos, sendo a TC indicada como ferramenta de monitoramento desses pacientes.

Intraventricular pneumocephalus associated with nasocephalic necrosis in a puppy: a case report / Pneumoencéfalo intraventricular associado à área de necrose nasoencefálica em filhote canino: relato de caso

Pneumocephalus is defined as the presence of air in any of the intracranial compartments. Its most frequent causes are trauma and cranial surgery. Clinical signs occur as a result of increased intracranial pressure and vary with the location and extent of the lesion. A case involving a seven-month-old female Saint Bernard, who suffered cranial trauma caused by a bite to the face at ten days of age and had presented with seizures and localized pain four months previously is reported. A computed tomography scan of the skull revealed a nasocephalic mass with low contrast enhancement, bone lysis, and hypodensity (-940 Hounsfield units) of the lateral and third ventricles, indicating intraventricular pneumocephalus. During surgery, a fragment of the mass was collected for histopathological examination, which demonstrated the presence of multifocal areas of necrosis. The computed tomography (CT) is a reliable method for the characterization of intracranial lesions and diagnosis of pneumocephalus, whose occurrence must be considered in pathological processes in which there is increased intracranial pressure and in patients undergoing certain surgical procedures and anesthetic specific, and CT is indicated as a monitoring tool for these patients.(AU)

Pneumoencéfalo é definido como a presença de gás em quaisquer dos compartimentos intracranianos e possui como causas mais frequentes o traumatismo e cirurgias cranianas. Os sinais clínicos ocorrem como consequência do aumento de pressão intracraniana e variam conforme o local e a extensão da lesão. Relata-se o caso de uma cadela de sete meses de idade, da raça São Bernardo, que sofreu trauma por mordedura em face, quatro meses antes, apresentando crises convulsivas e sensibilidade dolorosa local desde então. O exame tomográfico do crânio revelou massa nasoencefálica com baixa captação de contraste, lise óssea e hipodensidade (-940HU) dos ventrículos laterais e terceiro ventrículo encefálico, caracterizando pneumoencéfalo intraventricular. Foi realizada intervenção cirúrgica e coleta de fragmento da massa para exame histopatológico, que demonstrou existência de necrose multifocal. O exame de tomografia computadorizada (TC) é um método confiável para a caracterização de lesões intracranianas e diagnóstico de pneumoencéfalo, cuja ocorrência deve ser considerada em processos patológicos nos quais há aumento da pressão intracraniana e em pacientes submetidos a alguns procedimentos cirúrgicos e anestésicos específicos, sendo a TC indicada como ferramenta de monitoramento desses pacientes.(AU)

Three years with a knife stuck in the brain / Três anos com uma faca cravada no encéfalo

Cranial stabbing injuries penetrating the brain are not commonly encountered. The cases in which the knife is retained constitute a challenge to the neurosurgeon. When a long-term permanence occurs, the reaction to the presence of the foreign body causes adherence to the nervous tissue and a higher risk is expected from the removal. The procedure should be performed with meticulous dissection and minimal oscillation of the blade thus avoiding damage to the adjacent structures. We report a case of a man who remained three years with a knife blade deeply lodged in the brain. After obtaining informed consent, the blade was removed; there were no postoperative complications. To our knowledge, this is the first case in which, after years of permanence, a knife blade was removed from the brain through a craniotomy.

Lesões cranianas por arma branca com penetração do encéfalo não são comuns. Os casos em que a faca encontra-se retida constituem um desafio para o neurocirurgião. Quando ocorre uma longa permanência, a reação à presença do corpo estranho causa aderência ao tecido nervoso e um maior risco é previsto para a remoção. O procedimento deve ser realizado com dissecção meticulosa e mínima oscilação da lâmina, evitando, assim, lesão das estruturas adjacentes. Apresentamos o caso de um indivíduo que permaneceu três anos com a lâmina de uma faca alojada profundamente no encéfalo. Após obtermos consentimento informado, a lâmina foi removida; não houve complicações pós-operatórias. Até onde sabemos, este é o primeiro caso em que, após anos de permanência, a lâmina de uma faca foi removida do encéfalo por meio de uma craniotomia.

Microsurgical training model with nonliving swine head. Alternative for neurosurgical education

PURPOSE: This paper proposes a practical model of microneurosurgical training using a nonliving swine head. METHODS: Fresh porcine heads were obtained from butchery and dissected at our Laboratory of Microsurgery. Brain and skull base surgery were trained under microscopic magnification. RESULTS: Several neurosurgical procedures could be simulated in the nonliving pig model, including transcallosal approach to the lateral ventricle, lateral sulcus and middle fossa dissection, and posterior fossa surgery. CONCLUSION: The swine model perfectly simulates standard microneurosurgical procedures, and is a useful tool for developing and refining surgical skills. .

[Factors related to extubation failure and post pulmonary complications in intracranial surgery in 254 patients: a brief report]

The purpose of this study was to determine the prevalence and associated factors for postoperative pulmonary complications [PPCs] and extubation failure in patients having undergone intracranial surgery. In this retrospective study done in Firozgar Hospital during 2008-2010, we followed up 254 patients through a clinical questionnaire and observation of the clinical course of participants in pre- and post-operative periods. Overall, 40 [15.74%] patients had postoperative pulmonary complications. The most common PPC was pneumonia, which was seen in 24 patients [60% of complications]. The average duration of ventilation in patients with PPC was significantly higher [16.8. +/- 10 vs. 5.09 +/- 4.5 days; P=0.001] than patients without the complication. The mean Glasgow coma scale [GCS] after surgery in patients with PPC was significantly lower [11. +/- 4 vs. 13.2 +/- 3; P=0.001] than the rest of the patients. Moreover, the mean age of patients with PPC was significantly higher [64.02 +/- 14 vs. 41.6. +/- 17 years; P=0.001]. Average duration of stay in ICU in patients with PPC was also higher [24. +/- 27 vs. 8.7 +/- 0.5; P=0.001]. GCS before surgery and failed extubation independently of other variables were significantly associated with pulmonary complications independent of other variables

EEG spike source localization before and after surgery for temporal lobe epilepsy: a BOLD EEG-fMRI and independent component analysis study

Simultaneous measurements of EEG-functional magnetic resonance imaging (fMRI) combine the high temporal resolution of EEG with the distinctive spatial resolution of fMRI. The purpose of this EEG-fMRI study was to search for hemodynamic responses (blood oxygen level-dependent - BOLD responses) associated with interictal activity in a case of right mesial temporal lobe epilepsy before and after a successful selective amygdalohippocampectomy. Therefore, the study found the epileptogenic source by this noninvasive imaging technique and compared the results after removing the atrophied hippocampus. Additionally, the present study investigated the effectiveness of two different ways of localizing epileptiform spike sources, i.e., BOLD contrast and independent component analysis dipole model, by comparing their respective outcomes to the resected epileptogenic region. Our findings suggested a right hippocampus induction of the large interictal activity in the left hemisphere. Although almost a quarter of the dipoles were found near the right hippocampus region, dipole modeling resulted in a widespread distribution, making EEG analysis too weak to precisely determine by itself the source localization even by a sophisticated method of analysis such as independent component analysis. On the other hand, the combined EEG-fMRI technique made it possible to highlight the epileptogenic foci quite efficiently.

Analysis of X-knife and surgery in treatment of arteriovenous malformation of brain.

BACKGROUND: The goal of treatment in arteriovenous malformation (AVM) is total obliteration of the AVM, restoration of normal cerebral function, and preservation of life and neurological function. AIM: To analyze the results of X-knife and surgery for AVM of the brain. The endpoints for success or failure were as follows: success was defined as angiographic obliteration and failure as residual lesion, requiring retreatment, or death due to hemorrhage from the AVM. MATERIALS AND METHODS: From May 2002 to May 2007, 54 patients were enrolled for this study. Grade I AVM was seen in 9%, grade II in 43%, grade III in 26%, grade IV in 9%, and grade V in 13%. Thirty-eight patients were treated by microsurgical resection out of which Grade I was seen in 5 patients, Grade II was seen in 17 patients, Grade III was seen in 9 patients and Grade V was seen in 7 patients. Rest of the sixteen patients were treated by linear accelerator radiosurgery out of which Grade II was seen in 6 patients, Grade III was seen in 5 patients and Grade IV was seen in 5 patients. The follow up was in range of 3-63 months. In follow up, digital subtraction angiography/ magnetic resonance angiography (DSA/MRA) was performed 3 months after surgery and 1 year and 2 years after stereotactic radiosurgery (SRS). RESULTS: Among the patients treated with X-knife, 12/16 (75%) had proven angiographic obliteration. Complications were seen in 4/16 (25%) patients. Among the patients treated with microsurgical resection, 23/38 (61%) had proven angiographic obliteration. Complications (both intraoperative and postoperative) were seen in 19/38 (50%) patients. CONCLUSIONS: Sixty-one percent of patients were candidates for surgical resection. X-knife is a good modality of treatment for a low-grade AVM situated in eloquent areas of the brain and also for high-grade AVMs, when the surgical risk and morbidity is high.

The Thai Anesthesia Incidents (THAI Study) of anesthetic risk factors related to perioperative death and perioperative cardiovascular complications in intracranial surgery.

OBJECTIVE: To evaluate the correlations between anesthetic risk factors and perioperative cardiovascular complications as well as perioperative death within 72 hours. MATERIAL AND METHOD: This case controlled took the data from the Thai Anesthesia Incidents Study (THAI Study), a prospective multi-centered registry of anesthesia in Thailand. The authors included all the patients who received intracranial surgery from 20 hospitals throughout Thailand. The present study was divided into two groups and focused on anesthetic factors that possibly related to perioperative cardiovascular complications or perioperative death. The statistical analysis were Chi Square test and logistic regression model with the statistical significance if p-value < 0.05 demonstrated in Odds ratio (OR) and 95% confidence interval. RESULTS: From the 7,430 patients, there were 63 patients (0.85%) with perioperative cardiovascular complication. The American Society of Anesthesiologists (ASA) physical status 3-5 (OR 5.77, 95% CI 2.33-14.27) and the absence of anesthesiologists (OR 2.19, 95% CI 1.06-4.54) had statistical correlation with the cardiovascular complication. Eighty-four patients (1.13%) who died within 72 hours post operatively were found. The ASA physical status 3-5 (OR 10.14, 95% CI 3.42-30.02), the emergency circumstance (OR 3.55, 95% CI 1.31-9.60), and the absence of endtidal carbondioxide monitor (OR 2.27, 95% CI 1.26-4.09) had statistical correlation with the perioperative death. CONCLUSION: Predictors of perioperative cardiovascular complications in intracranial surgical patients were ASA physical status 3-5 and absence of certified board anesthesiologists. Risk factors of perioperative death were ASA physical status 3-5, emergency condition, and absence or no monitoring of capnometer.

Structural and functional repair of nerve circuits in the brain by neural transplants

The field of neural transplantation has developed dramatically over the last three decades both as an experimental tool for studying functional organization, development and plasticity in the nervous system, and as a powerful clinical technique for delivering novel cell therapies to the brain. The surgical techniques themselves have turned out to be relatively straightforward, whereas the big challenges have been [a] to understand the mechanisms of graft function so that targets for graft-derived repair can be selected on a rational basis, and [b] to generate suitable cells of the quality and specificity required to achieve functional repair in each disease context. In some circumstances it has turned out that relatively simple recovery processes [such as replacement of a deficient neurochemical] are sufficient to have a big impact on the host - whether a patient or experimental animal - whereas in other cases a true reconstruction of damaged brain pathways turns out to be necessary to achieve significant recovery. Although such a level of repair was once considered to be beyond the limits of the surgical technique - and may be of brain plasticity itself - it has become apparent over the last decade that in one or two model systems a quite remarkable degree of reconstruction is achievable, of which striatal degeneration and repair has provided the clearest example. In animals with experimental striatal degeneration, embryonic striatal grafts can survive, differentiate, connect, and function so as to sustain a remarkable degree of recovery, even in the highest aspects of thought and cognition. Moreover, detailed studies in grafted animals indicates that the graft neurons must - and do - become integrated within the neural circuitry of the host brain for successful recovery to be achieved, and that they then participate in the neuronal processing of the host brain in such processes as habit learning and synaptic plasticity. The principles identified in experimental animals are now leading to the development of new therapies for diseases of higher nervous system activity, such as Huntington's, in which cognitive and psychiatric as well as motor symptoms predominate, and may provide the foundation for the next generation of truly reparative therapies for a wide range of currently unbeatable neurodegenerative conditions

Epilepsy surgery in children and adolescence; Phramongkutklao College of Medicine's experience.

OBJECTIVES: To evaluate the safety and efficacy of epilepsy surgery in children and adolescence at Comprehensive Epilepsy Center, Phramongkutklao College of Medicine. MATERIAL AND METHOD: Children and adolescents, who underwent epilepsy surgery at Comprehensive Epilepsy Center, Phramongkutklao College of Medicine were identified from the epilepsy surgery database. The following parameters were evaluated: age at surgery, duration of seizure prior to surgery, presurgical work up, presurgical as well as postsurgical neurological/ seizure status and neuropathology (if applicable). All follow-up data were obtained through clinic visits. RESULTS: Fifteen children who underwent epilepsy surgery between January 1, 2003 and March 31, 2005 were identified. Age at surgery ranged from 2.5 years to 19 years (mean age=8.2 years). Seizure duration prior to surgery ranged from 1 year to 17 years (mean=4.7 years). Eight patients (53%) had partial seizures and underwent excisional procedures [5 temporal lobectomy, 2 left frontal corticectomy, and 1 left functional hemispherectomy]. Seven patients (47%) had generalized seizures and underwent anterior 2/3 corpus callosotomy. Pathological information was available for all 8 cases with partial epilepsy. Four out of eight cases with pathological information demonstrated cortical dysplasia, four revealed hippocampal sclerosis, and two patients had dysembryoplastic neuroepithelial tumor (DNET). At follow-up, all 5 patients with temporal lobectomy and a child who underwent functional hemispherectomy were seizure free (follow up period 3-31 months). Two children with extratemporal resective surgery [left frontal corticectomy] showed remarkable improvement with rare breakthrough seizures (follow up period= 3 and 19 months respectively). Four out of seven patients with corpus collosotomy had worthwhile improvement of seizures (follow up period=4-19 months), while another two children were seizure free during short-termed follow up postoperatively (follow up period=1 and 2 months). All patients did not have significant neurological deterioration or worsening of seizure after the surgery. CONCLUSION: Resective epilepsy surgery in Thai pediatric populations in the authors' experience seems to be safe and effective in selected patients. Most children who underwent callosotomy had a significant reduction in intensity and frequency of tonic, atonic, and tonic-clonic seizures. Dual pathology was common in refractory temporal lobe epilepsy with hippocampal sclerosis. Although the study sample was small, it did advocate several larger studies with the same findings.

Hemisferectomia funcional precoce na hemimegalencefalia associada à epilepsia refratária / Early functional hemispherectomy in hemimegalencephaly associated to refractory epilepsy

A hemimegalencefalia (HME) é malformação congênita cerebral rara de etiologia desconhecida que pode se apresentar com síndrome epiléptica de início precoce e resistente à terapia com anticonvulsivantes, associada a comprometimento significativo do desenvolvimento neuropsicomotor. A hemisferectomia funcional (HF) tem-se mostrado alternativa eficaz nos casos refratários à terapêutica medicamentosa. Em número diminuto, crianças foram operadas antes dos seis meses de idade. Esse estudo relata duas crianças com idade inferior a 6 meses com HME e síndrome epiléptica catastrófica submetidas a HF e com boa evolução clínica.

Ictal and interictal Tc-99M HM-PAO brain perfusion spect in medically intractable epilepsy: Addition of substraction technique

Twenty-one patients [15 males and 6 females] aged 23.7 +/- 6.9 years were presented with partial [focal] seizures intractable to medical therapy and candidates for surgery. All of them were subjected to brain perfusion SPECT using Tc-99 HM-PAO [10.6 MBq/kg body weight/study], in addition to MRI and EEG. SPECT were performed in the ictal [under inpatient video-EEG long term monitoring], interictal and both phases in 5, 9 and 7 patients, respectively. The results showed that all the above cases exhibited successful postoperative outcome of the partial seizures according to Engels' scale. In correlation with MRI, neurophysiologic, and/or surgical localization, and/or surgical outcome, accurate localization of the epileptogenic focus was proved in all the seven cases [100%] with dual-phase and subtraction study. This successful localization was revealed in four cases each in the groups of the ictal [90%] and interictal [44%] studies, respectively. In conclusion, the dual-phase Tc-99m HM-PAO brain perfusion SPECT [ictal and interictal] with subsequent subtraction technique may be more accurate than either study alone for localization of epileptogenic focus in medically intractable epilepsy, particularly in cases with negative MRI

Safety of acute normovolemic haemodilution with hydroxyethyl starch during intracranial surgery.

The effect of acute normovolemic haemodilution on haemodynamics, serum osmolality and coagulation parameters was studied in 20 patients undergoing intracranial surgical procedures. After induction of anaesthesia, 740+/-153 ml of blood was collected and the same was replaced with an equal volume of 6% hexaethyl starch. Heart rate (HR), blood pressure (BP), central venous pressure (CVP) and end tidal carbon dioxide tension (Et CO2) were monitored for 45 min. Haemoglobin concentration (Hb), haematocrit (Hct), serum osmolality (Osm), bleeding time (BT), prothrombin time (PT) and platelet count were determined before and 45 min after haemodilution. Hb and Hct were significantly lower following haemodilution (13.1+/-1.8 and 10.3+/-1.7 g/dL for Hb and 38.0+/-4.6%. and 30.1+/-4.5% for Hct). There was no significant change in the HR, BP and Et CO2 throughout the study period. CVP increased marginally from 35 to 45 min but was within normal limits. There was no significant change in serum osmolality, bleeding time and prothrombin time following haemodilution. Platelet count decreased following haemodilution but the values were within normal limits. The brain relaxation, as assessed by a semiquantitative scale, was satisfactory in all cases. None of the patients developed intraoperative brain swelling. In conclusion, acute normovolemic haemodilution with hexaethyl starch is tolerated well haemodynamically. It does not cause changes in serum osmolality which can increase brain oedema. It has no adverse effect on intraoperative haemostasis. It is a safe technique to decrease homologous blood transfusion during intracranial surgery.

Surgeon's perspective in intractable childhood epilepsy.

There is increased interest in the surgical management of epilepsy in children in the last decade or two. The plasticity of the developing brain and realization of the deleterious effects of uncontrolled seizures on the brain have prompted earlier surgery where indicated. All patients with uncontrolled partial seizures are potential candidates for surgery and merit a detailed presurgical evaluation. This consists of a detailed neurological evaluation, EEG, video EEG, a high resolution MRI, SPECT, and a neuropsychological evaluation. The outcome of properly selected cases for surgery is excellent and it offers the possibility of a cure. However, close coordination of a multidisciplinary team is essential for the successful implementation of any epilepsy surgery program.

Trasplante de celulas nerviosas en enfermedades neurodegenerativas / Nervous cells transplantation in neurodegenerative diseases

Este artículo es una revisión bibliográfica acerca de los avances científicos sobre el trasplante de tejido nervioso, tanto en animales de experimentación como en humanos, para el tratamiento de enfermedades neurodegenerativas, particularmente en la enfermedad de Parkinson. Los datos muestran la posibilidad que tiene el trasplante de tejido nervioso de aliviar los síntomas típicos de algunas de estas enfermedades que afectan al sistema nervioso. Desde las primeras investigaciones en 1890 hasta la actualidad ha habido un importante progreso en este campo. Los datos aquí presentados llevan a pensar que el trasplante de tejido nervioso podría realizarse en la práctica clínica como actualmente se realizan otros trasplantes de tejido.