Corona mortis and pelvic dissection: Understanding the relationship between anatomical structures and bone areas.

Pelvic fractures are becoming increasingly frequent. The gold standard for surgical managements remains open procedures. Despite its excellent biomechanically results, it can lead to many complications. Minimally invasive surgery could reduce these complications. For complex pelvic trauma, extraperitoneal endoscopic technique has never been described. The aim of this study is to determine anatomical landmarks which are useful for endoscopic pelvic ring surgery using an extraperitoneal approach. The second objective is to compare this minimally invasive procedure to expose the bone versus a traditional open approach. After preparing the vessels with latex injections, 10 specimens are dissected alternately, using an endoscopic method (MIS) on one side and an open method on the other side. Both procedures are performed on the same subject. The visualized bone areas are drilled with burr holes. The marked surfaces are measured with photogrammetry. Finally, the data are processed (surface analysis). An extraperitoneal endoscopic dissection that follows anatomical landmarks can be performed. Bone area (mm2 ) visualized by endoscopy was 74 ± 14 (59-94) compared to 71 ± 16 (48-94) by open method. Paired t-test was performed with no significant difference between the two methods. Skin and muscular incisions were significantly lower in the MIS group (5.1, IC95% [4.1; 6.1], p < 0.001). An extraperitoneal endoscopic dissection of the pelvis can be performed. We also find no significant difference between our method and an open traditional approach concerning bone exposure. We offer a holistic approach to treat pelvic fractures by identifying key anatomical structures.

Mixed reality compared to the traditional ex cathedra format for neuroanatomy learning: the value of a three-dimensional virtual environment to better understand the real world.

OBJECTIVE: Neuroanatomy comprehension is a keystone of understanding intracranial surgeries. Traditionally taught to students during ex cathedra courses, neuroanatomy is described as complex. Mixed reality (MxR) opens new perspectives in the learning process. This study aims to compare MxR-based courses with traditional ex cathedra lectures for neuroanatomy education. METHODS: Two lectures describing the neuroanatomy of the anterior circulation arteries ("Vascular Lecture" [VS]) and important white matter fiber tracts ("White Fibers Lecture" [WF]) were designed and delivered in ex cathedra and MxR-based formats with the same audio content. Ninety-one medical students were randomly assigned to group A (ex cathedra WF/MxR VS) or group B (MxR WF/ex cathedra VS). The MxR content was delivered via MxR goggles. Prior to each lecture, students took a 10-item multiple choice question (MCQ) pretest. After the lectures, students took a 20-item MCQ posttest (75% neuroanatomy, 25% clinical correlation). RESULTS: The pretest scores showed no statistical difference between groups. Median posttest scores increased by 14.3% after using the MxR-based format compared to the ex cathedra format (16.00 [13.0, 18.0] vs 14.0 [11.0, 17.0], respectively, p < 0.01). Regarding the VS, students scored 21.7% better using the MxR format compared to the ex cathedra format (14.0 [12.0, 16.0] vs 11.5 [10.0, 14.0], p < 0.001). Concerning the WF, the median score using MxR was 18.0 (17.0, 19.0), and the median score using the ex cathedra format was 17.0 (16.0, 18.0; p < 0.01). Students showed high motivation to learn neuroanatomy in the future using MxR (74%) rather than ex cathedra format (25%; p < 0.001). Mild discomfort using the MxR goggles was reported by 48.3% of participants. Most participants (95.5%) preferred the MxR-based teaching. CONCLUSIONS: Students acquired a better knowledge of the anatomy of the anterior circulation arteries and white fiber tracts using MxR-based teaching as compared to the standard ex cathedra format. The perception of lecture quality and learning motivation was better using MxR-based teaching despite some mild discomfort. The development of MxR-based solutions is promising to improve neuroanatomy education.

Clipping Versus Coiling for Ruptured MCA Aneurysms Associated with Intracerebral Hematoma Requiring Surgical Evacuation.

BACKGROUND: Ruptured middle cerebral artery aneurysm (MCAa) can lead to intracerebral hematoma, and surgical evacuation can be performed in these cases. MCAa can be treated by clipping or before by endovascular therapy (EVT). Our objective was to compare the impact on the functional outcome of MCAa in patients with intracerebral hematoma requiring evacuation. METHODS: This is a multicenter, retrospective, cohort study with nine French neurosurgical units from January 1, 2013, to December 31, 2020. All participants were adult patients who required evacuation of an intracerebral hematoma. We looked for risk factors for poor outcomes by comparing the baseline characteristics and treatments performed by using the 6-month modified Rankin scale score. Poor outcomes were defined by an modified Rankin scale score of 3-6. RESULTS: A total of 162 patients were included. A total of 129 (79.6%) patients were treated by microsurgery, and 33 (20.4%) patients were treated by EVT. In multivariate analysis, factors associated with poor outcomes included hematoma volume, realization of a decompressive craniectomy, occurrence of procedure-related symptomatic cerebral ischemia, occurrence of delayed cerebral ischemia, and EVT. In the propensity score matching analysis (n = 33 per group), poor outcomes were observed in 30% of the patients in the clipping group versus 76% in the EVT group (P < 0.001). These differences may have been related to a longer delay between hospital admission and hematoma evacuation in the EVT group. CONCLUSIONS: In the specific subgroup of ruptured MCAa with intracerebral hematoma that requires surgical evacuation, clipping with concomitant hematoma evacuation could provide better functional outcomes than EVT followed by surgical evacuation.

Peculiarities of aminoacyl-tRNA synthetases from trypanosomatids.

Trypanosomatid parasites are responsible for various human diseases, such as sleeping sickness, animal trypanosomiasis, or cutaneous and visceral leishmaniases. The few available drugs to fight related parasitic infections are often toxic and present poor efficiency and specificity, and thus, finding new molecular targets is imperative. Aminoacyl-tRNA synthetases (aaRSs) are essential components of the translational machinery as they catalyze the specific attachment of an amino acid onto cognate tRNA(s). In trypanosomatids, one gene encodes both cytosolic- and mitochondrial-targeted aaRSs, with only three exceptions. We identify here a unique specific feature of aaRSs from trypanosomatids, which is that most of them harbor distinct insertion and/or extension sequences. Among the 26 identified aaRSs in the trypanosome Leishmania tarentolae, 14 contain an additional domain or a terminal extension, confirmed in mature mRNAs by direct cDNA nanopore sequencing. Moreover, these RNA-Seq data led us to address the question of aaRS dual localization and to determine splice-site locations and the 5'-UTR lengths for each mature aaRS-encoding mRNA. Altogether, our results provided evidence for at least one specific mechanism responsible for mitochondrial addressing of some L. tarentolae aaRSs. We propose that these newly identified features of trypanosomatid aaRSs could be developed as relevant drug targets to combat the diseases caused by these parasites.

Does general comorbidity impact the postoperative outcomes after surgery for large and giant petroclival meningiomas?

We assessed the role of the general condition of the patient in addition to usual anatomical reasoning to improve the prediction of personalized surgical risk for patients harboring a large and giant petroclival meningiomas. Single-center, retrospective observational study including adult patients surgically treated for a large and giant petroclival meningioma between January 2002 and October 2019 in a French tertiary neurosurgical skull-base center by one Neurosurgeon. Inclusion criteria were as follows: (1) histopathologically proven meningioma; (2) larger than 3 cm in diameter; (3) located within the upper two-thirds of the clivus, the inferior petrosal sinus, or the petrous apex around the trigeminal incisura, medial to the trigeminal nerve. Clinical and radiological characteristics were gathered preoperatively including ASA score, the modified frailty index, and the Charlson comorbidity index. Post-operative severe neurological and non-neurological complications were collected. A total of 102 patients harboring a large and giant petroclival meningioma were included. The rate of postoperative death was 3.0% related to a congestive heart failure (n = 1), a surgical site hematoma (n = 1), and an ischemic stroke (n = 1). A severe neurological impairment was found in 12.8% and a severe non-neurological morbidity was found in 4.0%. The overall rate of severe morbidity and mortality was 15.7% after large and giant petroclival meningioma surgery. The presence of brainstem peri-tumoral edema (adjusted OR, 4.83 [95% CI 1.84-7.52], p = 0.028) was independently associated with a history of postoperative severe neurological morbidity. Male gender (adjusted OR, 7.42 [95% CI 1.05-49.77], p = 0.044), major cardiovascular morbidity (adjusted OR, 9.5 [95% CI 1.05-86.72], p = 0.045), and an ASA score ≥ 2 (adjusted OR, 11.09 [95% CI 1.46-92.98], p = 0.038) were independently associated with a history of postoperative severe non-neurological morbidity. A modified frailty index ≥ 1 (adjusted OR, 3.13 [95% CI 1.07-9.93], p = 0.047) and a low neurosurgical experience (adjusted OR, 5.38 [95% CI 1.38-20.97], p = 0.007) were independently associated with a history of postoperative overall morbidity and mortality. Pre-operative cranial nerve deficits (adjusted OR, 4.77 [95% CI 1.02-23.31], p = 0.024) and gross total resection (adjusted OR, 10.72 [95% CI 1.72-66.90], p = 0.022) were independently associated with postoperative new cranial nerve deficits. This study suggests to add scores assessing the patient general condition in daily practice to improve the selection of patients eligible for surgery. Collaborative international multicenter studies will be necessary to confirm these results and allow their implementation in clinical routine.

The trigeminal system: The meningovascular complex- A review.

Supratentorial sensory perception, including pain, is subserved by the trigeminal nerve, in particular, by the branches of its ophthalmic division, which provide an extensive innervation of the dura mater and of the major brain blood vessels. In addition, contrary to previous assumptions, studies on awake patients during surgery have demonstrated that the mechanical stimulation of the pia mater and small cerebral vessels can also produce pain. The trigeminovascular system, located at the interface between the nervous and vascular systems, is therefore perfectly positioned to detect sensory inputs and influence blood flow regulation. Despite the fact that it remains only partially understood, the trigeminovascular system is most probably involved in several pathologies, including very frequent ones such as migraine, or other severe conditions, such as subarachnoid haemorrhage. The incomplete knowledge about the exact roles of the trigeminal system in headache, blood flow regulation, blood barrier permeability and trigemino-cardiac reflex warrants for an increased investigation of the anatomy and physiology of the trigeminal system. This translational review aims at presenting comprehensive information about the dural and brain afferents of the trigeminovascular system, in order to improve the understanding of trigeminal cranial sensory perception and to spark a new field of exploration for headache and other brain diseases.

Augmented reality-assisted roadmaps during periventricular brain surgery.

Visualizing major periventricular anatomical landmarks intraoperatively during brain tumor removal is a decisive measure toward preserving such structures and thus the patient's postoperative quality of life. The aim of this study was to describe potential standardized preoperative planning using standard landmarks and procedures and to demonstrate the feasibility of using augmented reality (AR) to assist in performing surgery according to these "roadmaps." The authors have depicted stepwise AR surgical roadmaps applied to periventricular brain surgery with the aim of preserving major cognitive function. In addition to the technological aspects, this study highlights the importance of using emerging technologies as potential tools to integrate information and to identify and visualize landmarks to be used during tumor removal.

The ventral attention network: the mirror of the language network in the right brain hemisphere.

Resting-state functional MRI (RfMRI) analyses have identified two anatomically separable fronto-parietal attention networks in the human brain: a bilateral dorsal attention network and a right-lateralised ventral attention network (VAN). The VAN has been implicated in visuospatial cognition and, thus, potentially in the unilateral spatial neglect associated with right hemisphere lesions. Its parietal, frontal and temporal endpoints are thought to be structurally supported by undefined white matter tracts. We investigated the white matter tract connecting the VAN. We used three approaches to study the structural anatomy of the VAN: (a) independent component analysis on RfMRI (50 subjects), defining the endpoints of the VAN, (b) tractography in the same 50 healthy volunteers, with regions of interest defined by the MNI coordinates of cortical areas involved in the VAN used in a seed-based approach and (c) dissection, by Klingler's method, of 20 right hemispheres, for ex vivo studies of the fibre tracts connecting VAN endpoints. The VAN includes the temporoparietal junction and the ventral frontal cortex. The endpoints of the superior longitudinal fasciculus in its third portion (SLF III) and the arcuate fasciculus (AF) overlap with the VAN endpoints. The SLF III connects the supramarginal gyrus to the ventral portion of the precentral gyrus and the pars opercularis. The AF connects the middle and inferior temporal gyrus and the middle and inferior frontal gyrus. We reconstructed the structural connectivity of the VAN and considered it in the context if the pathophysiology of unilateral neglect and right hemisphere awake brain surgery.

Functional sparing surgery policy for giant vestibular schwannomas.

OBJECTIVE: The objective of this study was to compare the tumour control and facial nerve outcome according to the therapeutic strategy, that is extent of resection and post-operative radiotherapy. DESIGN: Retrospective study of patients with a giant vestibular schwannoma surgically treated from 4 academic skull base centres. SETTING: Extent of resection, neurological complications, facial nerve function, MRI follow-up and occurrence of complementary treatment were reviewed. PARTICIPANTS: Sixty patients were included from 2000 to 2018. MAIN OUTCOME MEASURES: Primary end points were comparison the tumour control rate and the post-operative House-Brackmann grade at last follow-up according to the extent of tumour removal (ie total or subtotal removal). Secondary end points were assessment risk factors of poor facial nerve function and comparison complication rate according to extent of tumour removal. RESULTS: Sixty patients had initial surgery at diagnosis. A total resection was realised in 21 cases and a subtotal resection in 39 cases. Thirteen patients needed further treatment. One patient had a recurrence and needed a second surgery 108 months after the initial total resection surgery. Twelve patients underwent post-operative radiotherapy, for an evolutive residual tumour. Tumour control was more successful in the total resection group (log-rank test, P = .015). There was no tumour recurrence after post-operative radiotherapy. The facial nerve outcome was significantly better in the subtotal resection group (Mean House-Brackmann grade at last follow-up: 2.2 ± 1.9) than in the total resection group (House-Brackmann grade: 3.5 ± 2.2) (P = .033). Vestibular schwannoma with a cystic component had better facial nerve outcome (P = .0082). Other than facial paralysis, neurological complications were observed in six patients (10% of patients): lower cranial nerves dysfunction in five cases and hemiparesis in one case. CONCLUSIONS: Subtotal resection of giant vestibular schwannomas leads to favourable tumour control and facial nerve function and therefore seems to be a valuable strategy.

Does 3D stereoscopy support anatomical education?

PURPOSE: The teaching of anatomy in medical education has historically been based on lectures, cadaveric dissections, and illustrated books for students. Stereoscopic 3D videos are now easily accessible via smartphone and affordable for students. This study aimed to investigate whether a 3D stereoscopic instruction video could improve learning over 2D video. METHODS: A prospective controlled study on a single-site was conducted at the University of Angers. Content knowledge was assessed, followed by the presentation of an instructional neuroanatomy video. Participants watched the video in either 3D or 2D format, then they completed an anatomy written test. Pre-video and post-video performances were analyzed with independent t tests on total score, fundamental anatomical knowledge, anatomical relationships and reasoning. RESULTS: 175 subjects completed the study. At baseline, the 3D (n = 91) and 2D (n = 86) groups were similar, in age and class level. 3D and 2D scores were similar in the pre-test session and in the fundamental knowledge post-test (mean 73.2% vs 74.4%, p = 0.37). Average scores for the 3D group were better for the post-test regarding anatomical relationships (mean 86.4% vs. 63.5%, p = 0.004), clinical inference/reasoning (mean 76.8% vs. 67.6%, p = 0.023) and total note (mean 76.8% vs. 67.6%, p = 0.07). Regarding the 3D student's satisfaction questionnaire (n = 91), 70 students (77%) agreed that the stereoscopic video allowed good 3D visualization of anatomical structures. The student enjoyed using the stereoscopic video (n = 75, 82.5%). Most students supported the use of this kind of stereoscopic 3D video in their normal teaching as a complementary tool (n = 78, 85%). CONCLUSIONS: The incorporation of 3D videos as ancillary teaching into curricula could be of interest to improve the knowledge of anatomical relationships and reasoning among students.

The modified retrosigmoid approach: a how I do it.

BACKGROUND: The traditional retrosigmoid (RS) approach provides limited exposure of the inferior compartment of the CPA, while radical skull base approaches are demanding and associated with significant morbidity. METHODS: This study outlines the relevant surgical anatomy and the different surgical steps of a modified retrosigmoid (MRS) approach. RESULTS: The MRS provides enhanced exposure of the CPA and deep vascular structures resulting from a modified RS craniotomy and limited exposure of the sigmoid sinus. CONCLUSION: In selected posterior fossa lesions, this cisternal approach is a straightforward corridor that can be routinely performed as a safe alternative to radical cranial base approaches.

Interfascial approach for pterional craniotomy: technique and adjustments to prevent cosmetic complications.

BACKGROUND: Interfascial dissection for pterional craniotomy is one of the main techniques to expose the pterional region. METHOD: A step-by-step optimized method of interfascial dissection to avoid three main esthetic complications of the pterional approach-upper facial nerve palsy, temporal muscle atrophy, and retro-orbital depression. A video of the interfascial dissection and three artistic drawings are provided in support of this technique. CONCLUSION: A safe method of interfascial dissection, respecting anatomy, and avoiding cosmetic complications has been proposed.

Morphological and functional anatomy of the trigeminal triangular plexus as an anatomical entity: a systematic review.

PURPOSE: The sensory trigeminal nerve in the trigeminal cave of Meckel-which is an individualized lodge-is classically segmented into two parts: the trigeminal ganglion (TG) and the triangular plexus (TP). The TP has been defined as the portion of the trigeminal nerve from the posterior margin of the TG to the path over the upper ridge of the petrous bone. Due to its relatively unrecognized status, its morphological and functional anatomy has been reviewed by the authors through a PRISMA systematic review of the literature. METHODS: The authors have carried out a systematic review of the TP according to the PRISMA model with various bibliographical bases. Before 1947: Medic @ Library (BIU Santé Paris, 2017); Index-Catalog of the Library of the Surgeon-General's Office (US National Library of Medicine, 2017); Gallica (French National Library, 2017). After 1947: PUBMED, PubMed Central and MEDLINE. RESULTS: 56 articles were retained for full-text examination, of which 23 were chosen and included. The TP was described as having a triangular shape (30.2%), a plexual organization (97.4%) with sensory-, motor- and sympathetic-anastomoses (96.7%) that, however, respect the somatotopic trigeminal distribution (93.3%). The direct electrical stimulation of the root at the level of the TP (during radiofrequency-thermorhizotomy procedures) confirmed a clear-cut somatotopy. CONCLUSION: An understanding of both the morphological and the functional anatomy of the triangular plexus can contribute to accuracy and safety on the surgeries performed for trigeminal neuralgia and tumor removal inside the trigeminal cave.

Anatomical variability of the arcuate fasciculus: a systematical review.

PURPOSE: The arcuate fasciculus (AF) is a white matter fibers tract that links the lateral temporal with the frontal cortex. The AF can be divided into three components: two superficial indirect short tracts (anterior and posterior) and one deep direct long tract. Both DTI and white matter dissections studies find differences regarding the anatomy of the AF, especially its cortical connections. This paper aims at providing a comprehensive anatomical classification of the AF, using the terminologia anatomica. METHODS: Articles (n = 478) were obtained from a systematical PRISMA review. Studies which focused on primates, unhealthy subjects, as well as studies without cortical termination description and review articles were excluded from the analysis. One hundred and ten articles were retained for full-text examination, of which 19 finally fulfilled our criteria to be included in this review. RESULTS: We classified main descriptions and variations of each segment of the AF according to fiber orientation and cortical connections. Three types of connections were depicted for each segment of the AF. Concerning the anterior segment, most of the frontal fibers (59.35%) ran from the ventral portion of the precentral gyrus and the posterior part of the pars opercularis, to the supramarginal gyrus (85.0%). Main fibers of the posterior segment of the AF ran from the posterior portion of the middle temporal gyrus (100%) to the angular gyrus (92.0%). In main descriptions of the long segment of the AF, fibers ran from both the ventral portion of the precentral gyrus and posterior part of the pars opercularis (63.9%) to the middle and inferior temporal gyrus (60.3%). Minor subtypes were described in detail in the article. CONCLUSION: We provide a comprehensive classification of the anatomy of the AF, regarding the orientation and cortical connections of its fibers. Although fiber orientation is very consistent, cortical endings of the AF may be different from one study to another, or from one individual to another which is a key element to understand the anatomical basis of current models of language or to guide intraoperative stimulation during awake surgery.

The tethered effect of the arachnoid in vago-glossopharyngeal neuralgia: a real associated alternative mechanism?

Vago-glossopharyngeal neuralgia (VGPN) is a rarely seen disease when compared to trigeminal neuralgia. When the pain is resistant to medical therapy, microvascular decompression can be performed if a vascular conflict is suspected on magnetic resonance imaging (MRI). In addition, arachnoid pathology may play a role in VGPN. We report two cases of VGPN caused by tethered arachnoid, associated with a vascular contact in which pain was reduced by freeing rootlets from arachnoid compression. We report two cases relating to 50-year-old and 30-year-old men with a history of electric shooting pain triggered by swallowing in the right pharyngeal and auricular regions. Preoperative MRI documented a neurovascular conflict in the first case and an arachnoid cyst in the second. Surgery was performed via a retrosigmoid craniotomy. In both cases, the intraoperative findings documented a tethered arachnoid membrane compressive to cranial nerves IX and X. Untethering was performed by liberation of the rootlets from the arachnoid with microvascular decompression. No additional rhizotomy was performed. The postoperative course was uneventful and pain was relieved in the first case and decreased in the second. In VGPN, a tethered arachnoid may play a role in causing the neuralgia, either alone or associated with a neuro-vascular conflict.

Using a Virtual Reality Social Network During Awake Craniotomy to Map Social Cognition: Prospective Trial.

BACKGROUND: In awake craniotomy, it is possible to temporarily inactivate regions of the brain using direct electrical stimulation, while the patient performs neuropsychological tasks. If the patient shows decreased performance in a given task, the neurosurgeon will not remove these regions, so as to maintain all brain functions. OBJECTIVE: The objective of our study was to describe our experience of using a virtual reality (VR) social network during awake craniotomy and discuss its future applications for perioperative mapping of nonverbal language, empathy, and theory of mind. METHODS: This was a single-center, prospective, unblinded trial. During wound closure, different VR experiences with a VR headset were proposed to the patient. This project sought to explore interactions with the neuropsychologist's avatar in virtual locations using a VR social network as an available experience. RESULTS: Three patients experienced VR. Despite some limitations due to patient positioning during the operation and the limitation of nonverbal cues inherent to the app, the neuropsychologist, as an avatar, could communicate with the patient and explore gesture communication while wearing a VR headset. CONCLUSIONS: With some improvements, VR social networks can be used in the near future to map social cognition during awake craniotomy. TRIAL REGISTRATION: ClinicalTrials.gov NCT03010943; https://clinicaltrials.gov/ct2/show/NCT03010943 (Archived at WebCite at http://www.webcitation.org/70CYDil0P).

Doxazosin, an α-1-adrenergic-receptor Antagonist, for Nightmares in Patients with Posttraumatic Stress Disorder and/or Borderline Personality Disorder: a Chart Review.

Objective: Centrally active α-1-adrenergic-receptor antagonists such as prazosin are effective in the treatment of nightmares in patients with posttraumatic stress disorder (PTSD). A pharmacological alternative is doxazosin, which has a longer half-life and fewer side effects. However, doxazosin is currently being used without solid empirical evidence. Furthermore, no study so far has assessed the effects of α-1-antagonists on nightmares in patients with borderline personality disorder (BPD). We retrospectively assessed the effectiveness of doxazosin on nightmares in PTSD and BPD. Method: A retrospective chart review of patients treated with doxazosin for trauma-associated nightmares in our clinic was performed. As in previous prazosin studies, the B2 score of the Clinician-Administered PTSD Scale (CAPS) was used as the primary outcome measure. Furthermore, the Pittsburgh Sleep Quality Index-Addendum for PTSD (PSQI-A) and sleep logs were analyzed. Results: We identified 51 patients with PTSD and/or BPD (mean age 35.7 years, 92.3% women) who received doxazosin for nightmares. Of these, 46 patients continued doxazosin over a 4-week period and 31 patients over a 12-week period. Within the 12-week period, doxazosin treatment significantly reduced nightmares regardless of PTSD/BPD. 25 percent of patients treated for 12 weeks had full remission of nightmares. PSQI-A scores indicated that additional trauma-associated sleep symptoms improved over 12 weeks. Furthermore, recuperation of sleep improved with doxazosin within the first 4 weeks of treatment. Conclusion: Doxazosin might improve trauma associated nightmares and more general sleep parameters in patients with PTSD and BPD. Randomized controlled trials are warranted.

The medial orbito-frontal approach for orbital tumors: a How I Do It.

BACKGROUND: A variety of lesions can affect the orbit. Surgical approaches must be available to provide 360 degrees of access. For tumors occupying the superomedial intraconal quadrant, there is a rationale to selecting the medial orbito-frontal approach. METHODS: This article outlines the relevant surgical anatomy and the different surgical steps of this approach. RESULTS: The medial orbito-frontal approach offers a full exposure of the superomedial intraconal quadrant and avoids crossing the plane of the optic nerve. CONCLUSION: In selected intraconal tumor cases, this transcranial epidural intraorbital approach is a straightforward corridor through reliable landmarks that can be routinely performed.

Susceptibility-Weighted MRI for Deep Brain Stimulation: Potentials in Trajectory Planning.

BACKGROUND: Deep brain stimulation (DBS) trajectory planning is mostly based on standard 3-D T1-weighted gadolinium-enhanced MRI sequences (T1-Gd). Susceptibility-weighted MRI sequences (SWI) show neurovascular structures without the use of contrast agents. The aim of this study was to investigate whether SWI might be useful in DBS trajectory planning. METHODS: We performed bilateral DBS planning using conventional T1-Gd images of 10 patients with different kinds of movement disorders. Afterwards, we matched SWI sequences and compared the visibility of vascular structures in both imaging modalities. RESULTS: By analyzing 100 possible trajectories, we found a potential vascular conflict in 13 trajectories based on T1-Gd in contrast to 53 in SWI. Remarkably, all vessels visible in T1-Gd were also depicted in SWI, whereas SWI showed many additional vascular structures which could not be identified in T1-Gd. CONCLUSION/DISCUSSION: The sensitivity for detecting neurovascular structures for DBS planning seems to be significantly higher in SWI. As SWI does not require a contrast agent, we suggest that SWI may be a valuable alternative to T1-Gd MRI for DBS trajectory planning. Furthermore, the data analysis suggests that vascular interactions of DBS trajectories might be more frequent than expected from the very low incidence of symptomatic bleedings. The explanation for this is currently the subject of debate and merits further studies.