Thalamic deep brain stimulation for post-traumatic neuropathic limb pain: Efficacy at five years' follow-up and effective volume of activated brain tissue.

Chronic neuropathic pain affects 7%-10% of the population. Deep brain stimulation (DBS) has shown variable but promising results in its treatment. This study prospectively assessed the long-term effectiveness of DBS in a series of patients with chronic neuropathic pain, correlating clinical results with neuroimaging. Sixteen patients received 5 years' post-surgical follow-up in a single center. Six had phantom limb pain after amputation and 10 had deafferentation pain after traumatic brachial plexus injury. Patient-reported outcome measures were completed before and after surgery, using VAS, UWNPS, BPI and SF-36 scores. Neuroimaging evaluated electrode location and effective volumes of activated tissue (VAT). Two subgroups were created based on the percentage of VAT superimposed upon the ventroposterolateral thalamic nucleus (eVAT), and clinical outcomes were compared. Analgesic effect was assessed at 5 years and compared to preoperative pain, with an improvement on VAS of 76.4% (p=0.0001), on UW-NPS of 35.2% (p=0.3582), on BPI of 65.1% (p=0.0505) and on SF-36 of 5% (p=0.7406). Eight patients with higher eVAT showed improvement on VAS of 67.5% (p=0.0017) while the remaining patients, with lower eVAT, improved by 50.6% (p=0.03607). DBS remained effective in improving chronic neuropathic pain after 5 years. While VPL-targeting contributes to success, analgesia is also obtained by stimulating surrounding posterior ventrobasal thalamic structures and related spinothalamocortical tracts.

Fulminant intracranial hypertension secondary to oxytetracycline requiring urgent ventriculo-peritoneal shunt insertion.

Idiopathic intracranial hypertension is a syndrome that presents with headaches and visual loss. Its pathogenesis is unknown. Treatment options include acetazolamide, therapeutic lumbar punctures or permanent CSF diversion. We present the only reported case of acute drug-induced intracranial hypertension secondary to oxytetracycline requiring urgent cerebrospinal fluid diversion. The patient's rapid visual failure progressed daily despite discontinuation of the drug and required an urgent ventriculo-peritoneal (VP) shunt insertion. Patients should be counselled about the rare potential risk of developing intracranial hypertension when commencing oxytetracycline. Rapid visual failure in IIH is a neurosurgical emergency necessitating urgent ventriculoperitoneal shunt insertion.

Neuroablative surgical treatments for pain due to cancer.

Cancer pain is common and challenging to manage - it is estimated that approximately 30% of cancer patients have pain that is not adequately controlled by analgesia. This paper discusses safe and effective neuroablative treatment options for refractory cancer pain. Current management of cancer pain predominantly focuses on the use of medications, resulting in a relative loss of knowledge of these surgical techniques and the erosion of the skills required to perform them. Here, we review surgical methods of modulating various points of the neural axis with the aim to expand the knowledge base of those managing cancer pain. Integration of neuroablative approaches may lead to higher rates of pain relief, and the opportunity to dose reduce analgesic agents with potential deleterious side effects. With an ever-increasing population of cancer patients, it is essential that neurosurgeons maintain or train in these techniques in tandem with the oncological multi-disciplinary team.

Intraspinal anomalies in early-onset idiopathic scoliosis.

AIMS: In the United Kingdom, lower incidences of intraspinal abnormalities in patients with early onset idiopathic scoliosis have been observed than in studies in other countries. We aimed to determine the rates of these abnormalities in United Kingdom patients diagnosed with idiopathic scoliosis before the age of 11 years. PATIENTS AND METHODS: This retrospective study of patients attending an urban scoliosis clinic identified 71 patients satisfying a criteria of: clinical diagnosis of idiopathic scoliosis; age of onset ten years and 11 months or less; MRI screening for intraspinal abnormalities. United Kingdom census data combined with patient referral data was used to calculate incidence. RESULTS: Mean age at diagnosis was six years with 39 right-sided and 32 left-sided curves. Four patients (5.6%) were found to have intraspinal abnormalities on MRI. These consisted of: two combined Arnold-Chiari type 1 malformations with syrinx; one syrinx with a low lying conus; and one isolated syrinx. Overall annual incidence of early onset idiopathic scoliosis was one out of 182 000 (0.0006%). CONCLUSION: This study reports the lowest rates to date of intraspinal anomalies in patients with early onset idiopathic scoliosis, adding to knowledge regarding current incidences of these abnormalities as well as any geographical variation in the nature of the disease. Cite this article: Bone Joint J 2017;99-B:829-33.

Role of radiology in central nervous system stimulation.

Central nervous system (CNS) stimulation is becoming increasingly prevalent. Deep brain stimulation (DBS) has been proven to be an invaluable treatment for movement disorders and is also useful in many other neurological conditions refractory to medical treatment, such as chronic pain and epilepsy. Neuroimaging plays an important role in operative planning, target localization and post-operative follow-up. The use of imaging in determining the underlying mechanisms of DBS is increasing, and the dependence on imaging is likely to expand as deep brain targeting becomes more refined. This article will address the expanding role of radiology and highlight issues, including MRI safety concerns, that radiologists may encounter when confronted with a patient with CNS stimulation equipment in situ.

Efeito da fração não-oleosa doRicinus communisna biodistribuição comTecnécio-99m em camundongos / Effect of non-oily fraction ofRicinus communis on the bio distribution with Technetium-99m in mice

RESUMO Ricinus communisé uma planta pertence à família Euforbiaceae. A partir de seus frutos é extraído o óleo de rícino e outra fração altamente tóxica (fração não-oleosa). Neste estudo, foi avaliado o efeito da fração não oleosa de R. communis(FNORC) na biodistribuição do Tc-99m em camundongos sadios e em animais transplantados com Sarcoma-180 (S180). Para avaliação da biodistribuição do Tc-99m, o percentual de atividade radioativa total injetada (ATI%) foi mensurada utilizando um contador gama. Os resultados mostraram que, em animais sadios, houve aumento da captação do Tc-99m após o tratamento com FNORC pelos rins, cérebro e estômago. Apenas houve diminuição da absorção deste radioisótopo nos músculos. Em animais com tumor, houve redução significativa da captação do Tc-99m no coração, pulmões e tumor, e foi observado o aumento da captação apenas nos rins. Foi observada também a diminuição da concentração das proteínas plasmáticas totais em animais com tumor após tratamento com FNORC e atividade antitumoral significativa. Diante desses dados, conclui-se que fração não oleosa de R. communis possui atividade antitumoral significativa, porém altera a biodistribuição do Tc-99m, fato este que pode resultar em falhas nos processos de diagnóstico por imagem que utilizem este radioisótopo como marcador.

ABSTRACT Ricinus communis is a plant belonging to the Euforbiaceae family. From its fruits, it is extracted the castor oil and another highly toxic fraction (non-oily fraction). In this study, we evaluated the effect of the non-oily fraction of R. communis (NOFRC) on the bio distribution of Tc-99m in healthy mice and in animals transplanted with Sarcoma-180 (S180). To evaluate the bio distribution of theTc-99m, the percentage of the total injected radioactivity (% TIR) was measured through a gamma counter. There was an increase in the capitation of Tc-99m after the treatment with NOFRC in the kidneys, brain, and stomach of healthy animals. A decrease in the reception of this radionuclide was only found in the muscles. In animals with tumour, there was a significant reduction in the uptake of Tc-99m in the heart, lungs and tumour. An increase in the capitation was only observed in the kidneys. It was also observed a reduction in the total plasma protein concentration in animals with tumours after the treatment with NOFRC, besides significant antitumor activity. We concluded that there is antitumor activity in the NOFRC, but that it alters the biodistribution of Tc-99m, a fact which may result in failures in the diagnostic imaging process using this radioisotope as a marker.

Acute foramen magnum syndrome from acquired Chiari I malformation relieved by ventriculoperitoneal shunt revision.

An adult case of shunt malfunction presenting with acute quadriparesis as a manifestation of foramen magnum syndrome with acquired Chiari type I malformation is described in this study. The corticospinal function was restored after shunt revision. MRI showing considerable ascent of cerebellar tonsils after surgery is shown. Theories regarding the formation of acquired Chiari I malformations, alongside the possible synergistic roles of intracranial pathologies and cerebrospinal fluid drainage in the development of this entity are discussed.

La maladie de Grisel treated by combined C1-2 transarticular and C1 lateral mass screw fixation.

The authors describe a novel posterior approach to atlantoaxial stabilization combining C1-2 transarticular and C1 lateral mass screws with vertical connecting rods to create a strong construct with four-point fixation. They present here a case of atlanto-axial instability secondary to infection, Grisel's syndrome, necessitating instrumented stabilization after a period of close clinical and radiological observation following the initial cervical decompression and evacuation of retropharyngeal and epidural abscesses.

Neurosurgery as a first foundation year training post.

Neurosurgery has traditionally been regarded as a surgical speciality unsuitable for doctors in their first clinical year after graduation with limited prior experience of such patients. However, the advent of UK Modernising Medical Careers' Foundation Year training and the European Working Time Directive mean neurosurgery is now available as a clinical placement for newly qualified doctors. The authors describe the development of such a post, first implemented in August 2008, which both facilitated safe and effective care of neurosurgical patients and enabled the trainee to achieve many of the goals of UK Foundation training. Suggestions are made for the implementation of further similar posts.

Posterior occipitocervical instrumented fusion for dropped head syndrome after deep brain stimulation.

We describe dropped head syndrome in a patient with Parkinson's disease receiving subthalamic nucleus deep brain stimulation (DBS). Posterior occipitocervical instrumented fusion after transarticular screw fixation of an odontoid fracture is shown and its rationale explained. Pedunculopontine nucleus DBS as treatment for fall-predominant Parkinson's disease, and globus pallidus interna DBS for dystonia-predominant Parkinson's disease, are discussed.

Neurosciences intensive care medicine in initial neurosurgical training.

The authors describe a novel 4-month clinical placement in neurosciences intensive care medicine (NICM) undertaken in the first specialty registrar (ST1) year of neurosurgical training as part of a clinical neurosciences themed training year. Neurosurgery is unique among British surgical specialties in having pioneered themed early years in run-through training to replace basic surgical training in general surgical specialties as part of Modernising Medical Careers. After describing events leading to the new neurosurgical training, the knowledge, skills and attitudes acquired in NICM are highlighted alongside discussion of logistic aspects and future directions from an inaugural experience.

Awake stereotactic brainstem biopsy via a contralateral, transfrontal, transventricular approach.

The authors describe a novel approach to stereotactic biopsy of lesions of the lateral pons and medial cerebellar peduncle, and its diagnostic success without morbidity. A contralateral approach laterally expands the accessible infratentorial area. It may also confer a theoretical reduction in neurological deficit with passage through non-dominant right hemisphere.

Pre-operative DTI and probabilisitic tractography in four patients with deep brain stimulation for chronic pain.

This study aimed to examine, using diffusion tensor imaging (DTI), differences in electrode placement in four patients undergoing deep brain stimulation for chronic neuropathic pain of varying aetiology. A pre-operative DTI was obtained for each patient, who was then implanted with deep brain stimulation electrodes in the periventricular/periaqueductal grey area with good pain relief. Using seeds from the postoperative MRI scan, probabilistic tractography was performed from the pre-operative DTI.

Parkinson's disease and primate research: past, present, and future.

Scientific research involving non-human primates has contributed towards many advances in medicine and surgery. This review discusses its role in the progress made towards our understanding of Parkinson's disease and its treatment. Established medical treatments like dopamine agonists continue to need primate models to assess their efficacy, safety, and mechanism of action. The recently developed treatment of deep brain stimulation of the subthalamic nucleus required validation in primates before entering the clinic. Controversies surrounding future treatments such as gene therapy show the need for properly evaluated preclinical research using appropriate animal models before progression to clinical trials. Research on primates has played--and continues to play--a crucial part in deepening our understanding of Parkinson's disease, improving current therapies, and developing new treatments that are both safe and effective. In animal research, the "three Rs" of humane technique--reduction, refinement, and replacement--should be adhered to.

Specific abnormalities in serotonin release in the prefrontal cortex of isolation-reared rats measured during behavioural performance of a task assessing visuospatial attention and impulsivity.

RATIONALE: Rats reared in social isolation exhibit hyperactivity and specific attentional disturbances in later adult life. These behavioural abnormalities may be relevant to impulsivity and other neuropsychiatric syndromes such as attention-deficit hyperactivity disorder and schizophrenia where disturbances in circuitry involving the prefrontal cortex have been identified. OBJECTIVE: To establish whether isolation-reared rats show a differential susceptibility to cognitive processes that depend on the prefrontal cortex and its monoaminergic innervation. METHODS: Rats were reared in isolation from postnatal day 28 or in social groups of four and trained on the five-choice serial reaction time task, which assesses spatially divided visual attention. Following a range of manipulations designed to tax visual attention and response control, in vivo microdialysis was used in conjunction with behavioural testing to assess dopamine (DA) and serotonin (5-HT) release in the prefrontal cortex, either under baseline conditions prior to task initiation, or during task performance. Subjects were challenged with amphetamine (0.125 mg/kg intravenously) every 15 min, commencing 15 min after the start of the task. RESULTS: Apart from being consistently slower to collect food rewards and showing more perseverative responses to an auditory distractor, isolates were unimpaired on accuracy, impulsivity and correct latency measures on the five-choice task. Basal levels of DA and 5-HT in the prefrontal cortex were also unaffected by isolation rearing. Amphetamine increased the speed of responding in control and isolation-reared animals and increased premature (impulsive) responding, but only in socially-reared animals. Cortical DA release increased to a similar extent in both groups following amphetamine challenge. By contrast, 5-HT release was attenuated in isolates under these conditions. CONCLUSIONS: These findings highlight a rather specific deficit in 5-HT release in the prefrontal cortex of isolation-reared rats, although this appears not to affect visual attentional function. Rather, these data may be relevant to reduced impulsiveness of isolation-reared rats on the five-choice task. These findings are important in the context of animal models of attentional disturbances in schizophrenia.