SummaryWe present a novel ultrasound-guided regional anaesthetic technique that may achieve complete paraesthesia of the hemithorax. This technique may be a viable alternative to current regional anaesthetic techniques such as thoracic paravertebral and central neuraxial blockade, which can be technically more challenging and have a higher potential side-effect profile. We performed the serratus block at two different levels in the midaxillary line on four female volunteers. We recorded the degree of paraesthesia obtained and performed fat-suppression magnetic resonance imaging and three-dimensional reconstructions of the spread of local anaesthetic in the serratus plane. All volunteers reported an effective block that provided long-lasting paraesthesia (750-840 min). There were no side-effects noted in this initial descriptive study. While these are preliminary findings, and must be confirmed in a clinical trial, they highlight the potential for the serratus plane block to provide analgesia following surgery on the thoracic wall. We suggest that this novel approach appears to be safe, effective, and easy to perform, and is associated with a low risk of sideeffects. Surgery on the chest wall is relatively common and can be associated with considerable postoperative discomfort and pain. Breast cancer has continued to be the most common cancer afflicting women, accounting for 31% of all new cancer cases in the female population [1,2]. Every year, thousands of patients undergo surgery in the region of the breast and axilla. These procedures cause significant acute pain and may progress to chronic pain states in 25-60% of cases [3]. Blockade of the lateral cutaneous branches of the thoracic intercostal nerves (T2-T12) will provide analgesia to the anterolateral chest wall in this patient population [4]. Patients undergoing other surgical procedures involving the chest wall, including anterior thoracotomy, may also benefit from thoracic nerve blockade to reduce postoperative pain.Following on from our previous work on the Pecs I and II blocks [5][6][7], we performed a detailed ultrasound examination of the relevant anatomy of the thoracic cage. This revealed two potential spaces, superficial and deep underneath the serratus anterior muscle, between the muscle and the intercostal nerves

BACKGROUND AND PURPOSE:Early prediction of motor outcome is of interest in stroke management. We aimed to determine whether lesion location at DTT is predictive of motor outcome after acute stroke and whether this information improves the predictive accuracy of the clinical scores.

Attention and executive deficits are disabling symptoms in multiple sclerosis (MS) that have been related to disconnection mechanisms. We aimed to investigate changes in structural connectivity in MS and their association with attention and executive performance applying an improved framework that combines high order probabilistic tractography and anatomical exclusion criteria postprocessing. We compared graph theory metrics of structural networks and fractional anisotropy (FA) of white matter (WM) connections or edges between 72 MS subjects and 38 healthy volunteers (HV) and assessed their correlation with cognition. Patients displayed decreased network transitivity, global efficiency and increased path length compared with HV (p < 0.05, corrected). Also, nodal strength was decreased in 26 of 84 gray matter regions. The distribution of nodes with stronger connections or hubs of the network was similar among groups except for the right pallidum and left insula, which became hubs in patients. MS subjects presented reduced edge FA widespread in the network, while FA was increased in 24 connections (p < 0.05, corrected). Decreased integrity of frontoparietal networks, deep gray nuclei and insula correlated with worse attention and executive performance (r between 0.38 and 0.55, p < 0.05, corrected). Contrarily, higher strength in the right transverse temporal cortex and increased FA of several connections (mainly from cingulate, frontal and occipital cortices) were associated with worse functioning (r between − 0.40 and − 0.47, p < 0.05 corrected). In conclusion, structural brain connectivity is disturbed in MS due to widespread impairment of WM connections and gray matter structures. The increased edge connectivity suggests the presence of reorganization mechanisms at the structural level. Importantly, attention and executive performance relates to frontoparietal networks, deep gray nuclei and insula. These results support the relevance of network integrity to maintain optimal cognitive skills.

OBJECTIVE Exposure of the cavernous sinus is technically challenging. The most common surgical approaches use well-known variations of the standard frontotemporal craniotomy. In this paper the authors describe a novel ventral route that enters the lateral wall of the cavernous sinus through an interdural corridor that includes the removal of the greater sphenoid wing via a purely endoscopic transorbital pathway. METHODS Five human cadaveric heads (10 sides) were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. To expose the lateral wall of the cavernous sinus, a superior eyelid endoscopic transorbital approach was performed and the anterior portion of the greater sphenoid wing was removed. The meningo-orbital band was exposed as the key starting point for revealing the cavernous sinus and its contents in a minimally invasive interdural fashion. RESULTS This endoscopic transorbital approach, with partial removal of the greater sphenoid wing followed by a "natural" ventral interdural dissection of the meningo-orbital band, allowed exposure of the entire lateral wall of the cavernous sinus up to the plexiform portion of the trigeminal root and the petrous bone posteriorly and the foramen spinosum, with the middle meningeal artery, laterally. CONCLUSIONS The purely endoscopic transorbital approach through the meningo-orbital band provides a direct view of the cavernous sinus through a simple and rapid means of access. Indeed, this interdural pathway lies in the same sagittal plane as the lateral wall of the cavernous sinus. Advantages include a favorable angle of attack, minimal brain retraction, and the possibility for dissection through the interdural space without entering the neurovascular compartment of the cavernous sinus. Surgical series are needed to demonstrate any clinical advantages and disadvantages of this novel route.

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The purpose of the present study was to analyze the relationships of the trochlear nerve with the surrounding structures through both endoscopic and microscopic perspectives. The aim was to assess the anatomy of the nerve and to carry out a thorough description of its entire course. A comprehensive anatomically and clinically oriented classification of its different segments is proposed. Forty human cadaveric fixed heads (20 specimens) were used for the dissection. The arterial and venous systems were injected with red and blue colored latex, respectively, in the transcranial dissection. For illustrative purposes, the arterial vessels were injected alone in endoscopic endonasal procedures. A CT scan was carried out on every head. Median supracerebellar infratentorial, subtemporal, fronto-temporo-orbito-zygomatic, and endoscopic endonasal transsphenoidal approaches were performed to expose the entire pathway of the nerve. A navigation system was used during the dissection process to perform the measurements and postoperatively to reconstruct, using dedicated software, a three-dimensional model of the different segments of the nerve. The trochlear nerve was divided into five segments: cisternal, tentorial, cavernous, fissural, and orbital. Detailed and comprehensive examination of the basic anatomical relationships through the view of transcranial, endoscope-assisted, and pure endoscopic endonasal approaches was achieved. As a result of a thorough study of its intra- and extradural pathways, an anatomic-, surgically, and clinically based classification of the trochlear nerve is proposed. Precise knowledge of the involved surgical anatomy is essential to safely access the supracerebellar region, middle fossa, parasellar area, and orbit.

The superior orbital fissure is a critical three-dimensional space connecting the middle cranial fossa and the orbit. From an endoscopic viewpoint, only the medial aspect has a clinical significance. It presents a critical relationship with the lateral sellar compartment, the pterygopalatine fossa and the middle cranial fossa. The connective tissue layers and neural and vascular structures of this region are described. The role of Muller's muscle is confirmed, and the utility of the maxillary and optic strut is outlined. Muller's muscle extends for the whole length of the inferior orbital fissure, passes over the maxillary strut and enters the superior orbital fissure, representing a critical surgical landmark. Dividing the tendon between the medial and inferior rectus muscle allows the identification of the main trunk of the oculomotor nerve, and a little laterally, it is usually possible to visualize the first part of the ophthalmic artery. Based on a better knowledge of anatomy, we trust that this area could be readily addressed in clinical situations requiring an extended approach in proximity of the orbital apex.

Three-dimensional (3D) or volumetric visualization is a useful resource for learning about the anatomy of the human brain. However, the effectiveness of 3D spatial visualization has not yet been assessed systematically. This report analyzes whether 3D volumetric visualization helps learners to identify and locate subcortical structures more precisely than classical cross-sectional images based on a two dimensional (2D) approach. Eighty participants were assigned to each experimental condition: 2D cross-sectional visualization vs. 3D volumetric visualization. Both groups were matched for age, gender, visual-spatial ability, and previous knowledge of neuroanatomy. Accuracy in identifying brain structures, execution time, and level of confidence in the response were taken as outcome measures. Moreover, interactive effects between the experimental conditions (2D vs. 3D) and factors such as level of competence (novice vs. expert), image modality (morphological and functional), and difficulty of the structures were analyzed. The percentage of correct answers (hit rate) and level of confidence in responses were significantly higher in the 3D visualization condition than in the 2D. In addition, the response time was significantly lower for the 3D visualization condition in comparison with the 2D. The interaction between the experimental condition (2D vs. 3D) and difficulty was significant, and the 3D condition facilitated the location of difficult images more than the 2D condition. 3D volumetric visualization helps to identify brain structures such as the hippocampus and amygdala, more accurately and rapidly than conventional 2D visualization. This paper discusses the implications of these results with regards to the learning process involved in neuroimaging interpretation.