Neurosurgical training outside the operating room has become a priority for all neurosurgeons around the world. The exponential increase in the number of publications on training in neurosurgery ...reflects changes in the environment that future neurosurgeons are expected to work in. In modern practice, patients and medicolegal experts demand objective measures of competence and proficiency in the growing list of techniques available to treat complex neurosurgical conditions. It is important to ensure the myriad of training models available lead to tangible improvements in the operating room. While neuroanatomy textbooks and atlases are continually revised to teach the aspiring surgeon anatomy with a three-dimensional perspective, developing technical skills are integral to the pursuit of excellence in neurosurgery. Parapharsing William Osler, one of the fathers of neurosurgical training, without anatomical knowledge we are lost, but without the experience and skills from practice our journey is yet to begin. It is important to constantly aspire beyond competence to mastery, as we aim to deliver good outcomes for patients in an era of declining case volumes. In this article, we discuss, based on the literature, the most commonly used training models and how they are integrated into the treatment of some surgical brain conditions.
Mutations of the phosphatase and tensin homolog (PTEN) gene have been associated with a spectrum of disorders called PTEN hamartoma tumor syndrome, which predisposes the individual to develop various ...types of tumors and vascular anomalies. Its phenotypic spectrum includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), Proteus syndrome, autism spectrum disorders (ASD), some sporadic cancers, Lhermitte-Duclos disease (LDD), and various types of associated vascular anomalies.
A previously healthy 27-year-old woman was experiencing visual scintillating scotomas and mild chronic headaches for the past 2 years. The initial computed tomographic (CT) and magnetic resonance imaging (MRI) scans did not reveal any abnormalities, but the possibility of pseudotumor cerebri was considered. Furthermore, a cerebral angiogram showed a posterior fossa dural arteriovenous fistula (dAVF), which was initially treated through embolization. However, in spite of proper treatment, this patient experienced multiple recurrent dAVFs in different locations, requiring multiple embolizations and surgeries. Despite exhibiting altered cerebral perfusion and hemodynamics, the patient did not display any significant symptoms until she experienced a sudden stroke resulting from deep venous thrombosis, which was not associated with any medical procedures or medication use. A comprehensive analysis was performed due to the aggressive nature of the dAVFs. Surprisingly, exome sequencing of a blood sample revealed a PTEN gene variant in chromosome 10, indicative of Cowden syndrome. However, no tumors or other vascular lesions were detected in other systems that would constitute Cowden syndrome.
The rapid formation of multiple and complex dAVFs, coupled with not meeting the criteria for any other PTEN-related syndrome, unequivocally leads to the presentation of a novel phenotype of the PTEN germline variant.
Deep cavernomas of eloquent areas, located in the region of the basal nuclei and thalamus, account for 9 to 36% of these encephalic vascular malformations. Internal capsule cavernomas are ...particularly challenging, as they are surrounded by important projection fibers and their manipulation can lead to permanent deficits. To demonstrate through surgical cases that cavernomas of the internal capsule can be approached by frontal craniotomy, via the superior frontal sulcus, in a curative manner and with low morbidity.
We presented two cases of cavernomas of the internal capsule operated, whose treatment was microsurgical resection via frontal craniotomy and access to the lesion via the superior frontal sulcus, described step-by-step. To elucidate the rationale behind the decision, we used preoperative images with an emphasis on the patients' tractography and the importance of comparing these images with anatomical specimens dissected in the neuroanatomy and microsurgery laboratory.
The two cases of internal capsule cavernomas, one in the anterior limb and the other in the posterior limb, were treated surgically via the superior frontal sulcus.
Both patients showed radiological cure and clinical improvement in the post-operative segment. The patient consented to the procedure and to the publication of his/her image. Treatment of internal capsule cavernomas via the superior frontal sulcus has proven to be a safe and effective option.
The endocannabinoid system has been implicated in the neurobiology of opioid use disorder. While the CB1 receptor antagonist rimonabant has been shown to block some of the behavioral effects of ...opioids, studies suggest that the treatment environment (i.e., receiving treatment in the drug-associated environment, and/or novelty) can influence its effects. In the present study, we investigated the role of the treatment environment in the effects of rimonabant on the expression of morphine-induced behavioral sensitization.
Adult female Swiss mice were submitted to a behavioral sensitization protocol, during which they received morphine (20 mg/kg, i.p.) in the open-field apparatus, and were subsequently treated with vehicle or rimonabant (1 or 10 mg/kg, i.p.) either in the open-field, in the home-cage or in an activity box (novel environment). The expression of conditioned locomotion (increased locomotor activity in the open-field apparatus in the absence of morphine) and of morphine-induced behavioral sensitization (increased locomotor activity in animals sensitized to morphine) was evaluated during asubsequent saline and morphine challenge, respectively.
Animals treated with morphine expressed behavioral sensitization, showing a significant increase in locomotor activity over time. Animals sensitized to morphine and treated with vehicle in the home-cage expressed conditioned locomotion, an effect that was blocked by home-cage treatment with rimonabant. During a saline challenge, only animals sensitized to morphine and treated with saline in the home-cage expressed morphine-induced conditioned locomotion. All morphine-treated animals that received saline during the treatment phase (control groups) expressed behavioral sensitization during the morphine challenge. Treatment with rimonabant in the open-field and in the activity box, but not in the home-cage, blocked the expression of morphine-induced behavioral sensitization.
Our findings suggest that CB1 receptor antagonism can modulate conditioned responses to morphine even when administered in the home-cage. However, exposure to the drug-associated environment or to a novel environment is necessary for the expression of rimonabant's effects on morphine-induced behavioral sensitization during a morphine challenge.
Anterior clinoidectomy is an important procedure used in the treatment of a range of diseases of the frontotemporal region, both vascular and tumoral. Mastering this technique requires a high level ...of manual skills training. The objective of the study was to describe an easily accessible and economical alternative model of anterior clinoidectomy, with a principal focus on the significance of mastering technical skills and training tactile feedback.
Five cadaveric sheep heads (10 sides) fixed in formalin and alcohol were injected with silicone and used to simulate extradural (5 sides) and intradural (5 sides) routes and 1 head was used to prepare an anatomic specimen for better demonstration of the anatomy of the paraclinoid region.
A comparative anatomic analysis between the ovine and human anterior clinoid process was performed. Using cadaveric sheep models, all principal steps of the procedure for both the extradural and the intradural routes were imitated.
A cadaveric sheep head model serves as a good model of anterior clinoidectomy regarding manual skills training and can serve as a good alternative to human cadaveric training.
Pain is a distressful experience that can have a major impact on an individual's quality of life. The need for new and better analgesics has been further intensified in light of the current opioid ...epidemic. Substances obtained from amphibians have been shown to contain bioactive peptides that exert analgesic effects. The genus
represents an important source of peptides and bioactive components. The aim of this study was to investigate the antinociceptive effects of the skin secretion of
in rodent models of pain. The crude skin extract of
was tested in different pain models: acetic acid-induced writhing test (mice), formalin test (rats), Von Frey electronic test for hypernociception induced by PGE
(rats), and hot plate test (mice). Motor-impairing effects were tested using the rota-rod test. The results showed that the skin extract of
exerted antinociceptive effects in all pain models tested. Particularly, the highest dose tested of the skin extract decreased acetic acid-induced writhing by 93%, completely blocked formalin-induced nociception both during the acute and inflammatory phases of the test, PGE
-induced hypernociception by 73% and increased latency to paw withdrawal in the hot plate test by 300%. The effects observed in the hot plate test were reversed by pretreatment with selective µ and κ, but not δ, opioid receptor antagonists, indicating a mechanism of action dependent on µ and κ opioid receptors. The results were not influenced by sedative effects. Further studies remain necessary to reveal the specific compounds involved in the antinociceptive effects of
skin extract as a new therapeutic tool in pain management.
Studies on the abuse potential of modafinil, a psychostimulant-like drug used to treat narcolepsy, are still controversial. While some studies claim no potential for abuse, increasing evidence ...suggests that modafinil induces abuse-related effects, including rapid-onset behavioral sensitization (i.e., a type of sensitization that develops within hours from the drug priming administration). The rapid-onset sensitization paradigm is a valuable tool to study the neuroplastic changes that occur quickly after drug administration, and shares neuroadaptations with drug abuse in humans. However, the mechanisms involved in the rapid-onset behavioral sensitization induced by modafinil are uncertain. Our aim was to investigate the possible involvement of dopamine D1 and D2 receptors on acute modafinil-induced hyperlocomotion and on the induction and expression of rapid-onset behavioral sensitization induced by modafinil in male Swiss mice. Treatment with the D1 receptor antagonist SCH 23390 or the D2 receptor antagonist sulpiride attenuated the acute modafinil-induced hyperlocomotion in a dose-dependent manner. Pretreatment with either antagonist before the priming injection of modafinil prevented the development of sensitization in response to a modafinil challenge 4 h later. However, only SCH 23390 decreased the expression of modafinil-induced rapid-onset behavioral sensitization. Taken together, the present findings provide evidence of the participation of D1 and D2 receptors on the development of rapid-onset behavioral sensitization to modafinil, and point to a prominent role of D1 receptors on the expression of this phenomenon.
The present study aimed to characterize the phenomenon of behavioral sensitization to cocaine and to identify neuroanatomical structures involved in the induction and expression phases of this ...phenomenon. For this, in experiment 1 (induction phase), mice were treated with saline or cocaine every second day for 15 days (conditioning period), in the open-field or in their home-cages. In experiment 2 (expression phase), the same protocol was followed, except that after the conditioning period the animals were not manipulated for 10 days, and after this interval, animals were challenged with cocaine. Neuroanatomical structures involved in the induction and expression phases were identified by stereological quantification of c-Fos staining in the dorsomedial prefrontal cortex (dmPFC), nucleus accumbens core (NAc core and shell (NAc shell), basolateral amygdala (BLA), and ventral tegmental area (VTA). Neuroanatomical analysis indicated that in the induction phase, cocaine-conditioned animals had higher expression of c-Fos in the dmPFC, NAc core, BLA, and VTA, whereas in the expression phase, almost all areas had higher expression except for the VTA. Therefore, environmental context plays a major role in the induction and expression of behavioral sensitization, although not all structures that compose the mesolimbic system contribute to this phenomenon.
Neuroinflammation has been shown to play a crucial role in the development of Alzheimer's disease (AD) and also has an association with amyloid-β (Aβ) plaques, a hallmark of this disease. Physical ...exercise has emerged as an alternative treatment for pathological impairment in AD. In light of this evidence, together with the fact that the hippocampus is one of the first structures to be affected in AD, we analyzed hippocampal changes in Aβ load, inflammatory responses, and locomotor activity in transgenic APP/PS1 mouse model for AD submitted to a resistance exercise (RE) program. One month after the start of the RE program, the locomotor hyperactivity related to AD behavior was reduced and microglia recruitment was increased, which in turn may have contributed to the decrease in the volume of Aβ plaques. In addition, the RE program restored the levels of IL-1α, IL-4, and IL-6 cytokines to control levels. Our study indicates that RE has beneficial effects on the locomotor behavior, amyloid burden, and inflammation of AD pathology and can therefore be used as a therapy to improve the clinical symptoms and neurophysiological alterations in AD. To the best of our knowledge, this is the first study to use a resistance exercise program in transgenic AD model.
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