Trabeculae in the basilar venous plexus: anatomical and histological study with application to intravascular procedures.

Few studies have examined the basilar venous plexus (BVP) and to our knowledge, no previous study has described its histology. The present anatomical study was performed to better elucidate these structures. In ten cadavers, the BVP was dissected. The anatomical and histological evaluation of the intraluminal trabeculae within this sinus were evaluated. Once all gross measurements were made, the clivus and overlying BVP were harvested and submitted for histological analysis. A BVP was identified in all specimens and in each of these, intraluminal trabeculae were identified. The mean number of trabeculae per plexus was five. These were most concentrated in the upper half of the clivus and were more often centrally located. These septations traveled in a posterior to anterior direction and usually, from inferiorly to superiorly however some were noted to travel horizontally. In a few specimens the trabeculae had wider bases, especially on the posterior attachment to the meningeal layer of dura mater. More commonly, the trabeculae ended in a denticulate form at their two terminal ends. The trabeculae were on average were 0.85 mm in length. The mean width of the trabeculae was 0.35 mm. These septations were consistent with the cords of Willis as are found in the lumen of some of the other intradural venous sinuses. An understanding of the internal anatomy of the BVP can aid in our understanding of venous pathology. Furthermore, this knowledge will benefit patients undergoing interventional treatments that involve the BVP.

Revisiting the transorbital approach for emergency external ventricular drainage: an anatomical study of relevant parameters and their effect on the effectiveness of using Tubbs' point.

The transorbital approach (TOA) can provide immediate access to the lateral ventricles by piercing the roof of the orbit (ROO) with a spinal needle and without the need of a drill. Reliable external landmarks for the TOA ventriculostomy have been described, however, the necessary spinal needle gauge and other relevant parameters such as the thickness of the ROO have not been evaluated. Nineteen formalin-fixed adult cadaveric heads underwent the TOA. Spinal needles of different gauges were consecutively used in each specimen beginning with the smallest gauge until the ROO was successfully pierced. The thickness of the ROO at the puncture site and around its margins was measured. Other parameters were also measured. The TOA was successfully performed in 14 cases (73.68%), where the most suitable needle gauge was 13 (47.37%), followed by a 10-gauge needle (36.84%). The mean thickness of the ROO at the puncture site, and the mean length of the needle to the puncture site were 1.7 mm (range 0.2-3.4 mm) and 15.5 mm (range 9.2-23.4 mm), respectively. A ROO thickness of greater than 2.0 mm required a 10-gauge needle in seven cases, and in five cases, a 10-gauge needle was not sufficient for piercing the ROO. The presence of hyperostosis frontalis interna (HFI) (21.05%) was related to the failure of this procedure (80%; p < 0.00). Using a 13/10-gauge spinal needle at Tubbs' point for TOA ventriculostomy allowed for external ventricular access in most adult specimens. The presence of HFI can hinder this procedure. These findings are important when TOA ventriculostomy is considered.

Histology and immunohistochemistry of the human carotid sinus nerve.

The carotid sinus nerve (CSN) is well known as mediating baroreflexes. However, studies of its detailed histological analysis are scant in the literature. Therefore, the current anatomical study sought to better elucidate the microanatomy of the CSN. Ten fresh frozen adult cadavers underwent dissection of the CSN. Then, it was harvested and submitted for histological and immunohistochemical staining. Specimens were all shown to be nerve fibers on histology and immunohistochemistry. We identified tyrosine hydroxylase positive fibers in all CSN specimens. These fibers were always found to be within the CSN and not on its surface i.e., epineurium. Based on our findings, the majority of fibers contained in the CSN are tyrosine positive in nature. Further studies are necessary to understand the true function of this autonomic nerve fibers.

Direct Hemi-Hypoglossal Nerve and Hypoglossal Nerve for Suprascapular Nerve/Proximal Brachial Plexus Neurotization: A Cadaveric Feasibility Study.

Introduction Partial restoration of shoulder function is important in upper brachial plexus lesions, and the suprascapular nerve is often the target for such neurotization procedures. Although there is an extensive history of peripheral nerve surgeons using the hypoglossal nerve for various local nerve transfers, some have reported using this nerve as a donor for upper brachial plexus grafting procedures. We discuss our anatomical findings for the use of a direct hypoglossal to suprascapular nerve transfer. Materials and methods Fifteen adult cadavers (30 separate sides) were dissected to reveal the hypoglossal nerve in the neck and the supraclavicular brachial plexus in the supraclavicular region. On 15 sides, the hypoglossal nerve was dissected anteriorly to the midline, cut, and transposed toward the supraclavicular region in half of the dissections. On the remaining sides, the nerve was hemisected longitudinally into two equal parts, and the cut inferior portion also swung inferiorly toward the supraclavicular region. The cut end of the hypoglossal nerve was brought toward the proximal suprascapular nerve, the fifth (C5) and sixth (C6) cervical nerve roots, and the upper trunk. Measurements included the length and diameter of the cervical portion of the hypoglossal nerve and the diameter of the suprascapular nerve. Results The mean diameter and length of the hypoglossal nerve were 2.1 millimeters (mm) and 72.8 mm, respectively. The mean diameter of the proximal suprascapular nerve was 2.7 mm. Successful, tension-free transposition to the C5 and C6 nerve roots was achieved on all sides. The average extra length of the hypoglossal nerve for a C5 root transposition was 8 mm and 5.2mm for a C6 root transposition. The distal hypoglossal nerve reached the upper trunk on all but two sides (6.7%). The distal hypoglossal nerve reached the proximal suprascapular nerve on all but four sides (13.3%). Of the 87% of sides (n=26) where the hypoglossal nerve reached the proximal suprascapular nerve, 58% of these (n=15) required some manipulation of the suprascapular nerve from its origin at the upper trunk. This technique resulted in a mean additional length to the suprascapular nerve of 35 mm. No differences were found between the completely cut hypoglossal nerves and hemisected nerves in regard to working length. Conclusions To our knowledge, the use of the hypoglossal nerve as a transpositional graft for direct suprascapular nerve neurotization has not been previously described. Based on our study, we propose that the hypoglossal nerve, or hemi-hypoglossal nerve, should be considered as a donor nerve to restore suprascapular nerve function in the majority of patients. Additionally, the hypoglossal nerve may be transferred to the C5 and C6 roots and upper trunk of the brachial plexus for direct neurotization.

Effects of intubation technique on intracranial pressure: a cadaveric study.

Patients are at risk of increased intracranial pressure (ICP) during manipulation for endotracheal intubation. The aim of this cadaveric study was to quantify this relationship. Five fresh frozen adult cadaveric heads were used. The internal carotid artery (ICA) and internal jugular vein (IJV) were dissected bilaterally. All vessels were occluded on the right side. To mimic central venous pressures, the left IJV was cannulated and filled with water to maintain a pressure of approximately 7 cm H2O. The ICA cannula was attached to an oscillating water pump. Next, an ICP monitor was placed. Normophysiological volumes of water were infused to maintain normal ICP. Baseline ICP and IJV pressures were recorded. The heads were then placed in the sniffing position and in neutral position for nasal intubation, and finally an oral endotracheal tube was placed using standard head/neck maneuvers. The ICP was recorded. Mean baseline ICP was 13 mmHg (range 4-18 mmHg) and mean IJV pressure was 6 cm H2O. In the sniffing position, ICP increased in all specimens by a mean of 5 mmHg. In the neutral position, after intubation, the ICP increased in all specimens by a mean of 3 mmHg. Nasal intubation resulted in an increase in four of the five specimens. The mean increase in ICP with this maneuver was 2 mmHg. We present a cadaveric model of ICP measurement during neck manipulation using intracranial fluid dynamics. The ICP increased consistently. Following clinical studies, physicians involved in intubating patients with concern for raised ICP should change the technique to avoid complications.

Transradial access for anterior circulation deployment of pipeline embolization device: A case report, literature review, and technical note.

Common femoral artery (CFA) transfemoral access (TFA) has been the traditional route for neuroendovascular intervention with flow diversion including the pipeline embolization device (PED) for the treatment of wide-necked aneurysms. Successful deployment requires significant catheter support, thus making alternative access challenging. A 56-year-old-female presented with subarachnoid hemorrhage secondary to a large ruptured posterior communicating artery (PCOM) aneurysm as well as found to have an unruptured left superior cerebellar artery (SCA) aneurysm. Endovascular embolization of PCOM aneurysm via TFA was complicated by a right CFA pseudoaneurysm. The SCA aneurysm was treated 8 weeks later via left TFA with consequent development of a left CFA pseudoaneurysm. Contrasted magnetic resonance angiography revealed recurrence at the neck of the PCOM aneurysm at 4-month follow-up, treated via transradial access (TRA) PED flow diversion to avoid additional groin complications. Anatomic, procedural, and clinical considerations for TRA anterior circulation flow diversion using the PED are reviewed.

Lower cranial nerve syndromes: a review.

The purpose of this paper is to provide a comprehensive review encompassing the syndromes associated with the lower cranial nerves (LCNs). We will discuss the anatomy of some of these syndromes and the historical contributors after whom they were named. The LCNs can be affected individually or in combination, since the cranial nerves at this level share their courses through the jugular foramen and hypoglossal canal and the extracranial spaces. Numerous alterations affecting them have been described in the literature, but much remains to be discovered on this topic. This paper will highlight some of the subtle differences among these syndromes. Symptoms and signs that have localization value for LCN lesions include impaired speech, deglutition, sensory functions, alterations in taste, autonomic dysfunction, neuralgic pain, dysphagia, head or neck pain, cardiac or gastrointestinal compromise, and weakness of the tongue, trapezius, or sternocleidomastoid muscles. To assess the manifestations of LCN lesions correctly, precise knowledge of the anatomy and physiology of the area is required. Treatments currently used for these conditions will also be addressed here. Effective treatments are available in several such cases, but a precondition for complete recovery is a correct and swift diagnosis.

Multiple flow-related intracranial aneurysms in the setting of contralateral carotid occlusion: Coincidence or association?

The prevalence of intracranial aneurysms (IAs) is higher in patients with internal carotid artery (ICA) stenosis, likely due to alterations in intracranial hemodynamics. Severe stenosis or occlusion of one ICA may result in increased demand and altered hemodynamics in the contralateral ICA, thus increasing the risk of contralateral IA formation. In this article, we discuss a relevant case and a comprehensive literature review as it pertains to the association of ICA stenosis and IA. Our patient was a 50-year-old female with a chronic asymptomatic right ICA occlusion who presented with diffuse subarachnoid hemorrhage. Emergent angiography revealed left-sided A1-A2 junction, paraclinoid, left middle cerebral artery (MCA) bifurcation, and left anterior temporal artery aneurysms. Brisk filling of the right anterior circulation through the anterior communicating artery was also identified, signifying increased demand on the left ICA circulation. Complete obliteration of all aneurysms was achieved with coil embolization and clipping. For our literature review, we searched the PubMed and EMBASE databases for case reports and case series, as well as references in previously published review articles that described patients with concurrent aneurysms and ICA stenosis. We selected articles that provided adequate information about the case presentations to compare aneurysm and patient characteristics. Our review revealed a higher number of patients with multiple aneurysms contralateral (25%) to rather than ipsilateral to (6%), the ICA stenosis. We discuss the pathogenesis and management of multiple flow-related IA in the context of the existing literature related to concurrent ICA stenosis and IA.

Arterial Supply of the Thalamus: A Comprehensive Review.

The thalamus is a deep cerebral structure that is crucial for proper neurological functioning as it transmits signals from nearly all pathways in the body. Insult to the thalamus can, therefore, result in complex syndromes involving sensation, cognition, executive function, fine motor control, emotion, and arousal, to name a few. Specific territories in the thalamus that are supplied by deep cerebral arteries have been shown to correlate with clinical symptoms. The aim of this review is to enhance our understanding of the arterial anatomy of the thalamus and the complications that can arise from lesions to it by considering the functions of known thalamic nuclei supplied by each vascular territory.

The Retroverted Dens: A Review of its Anatomy, Terminology, and Clinical Significance.

BACKGROUND: Little attention has been given to the retroverted dens within the existing medical literature. However, this finding can have a clinical impact, especially in patients with Chiari malformation type I (CM1), as it can have consequences for further treatment. METHODS: Using standard search engines, we performed a literature review of anatomical, radiologic, and clinical studies as well as pathologic and surgical considerations related to the retroverted dens. Key words for our search included retroverted dens; retroflexed dens; odontoid retroflexion; posterior inclination; and tilted dens. RESULTS: A retroverted dens is most commonly found in the pediatric population in relation to CM1. Research has demonstrated that high degree of dens angulation can result in significant anterior brain stem compression with the need for both anterior and posterior decompression in patients with symptomatic CM1. CONCLUSIONS: A greater degree of dens angulation can lead to neurologic symptoms secondary to spinomedullary compression. Therefore, correct measurements are essential as such findings can influence presurgical planning.

Iatrogenic spinal cord injury with tetraplegia after an elective non-spine surgery with underlying undiagnosed cervical spondylotic myelopathy: Literature review and case report.

Cervical spondylotic myelopathy (CSM) can predispose to acute spinal cord injury and post-operative quadriparesis during non-spine procedures, although few accounts of this phenomenon exist within the literature. To the best of our knowledge, there are only 18 cases reported in the literature including ours with spinal cord injury following elective non-spine surgery with undiagnosed CSM. Due to multifactorial pathophysiology, the maintenance of cervical cord neutrality is not sufficient to ensure that these patients will not sustain cord injury intraoperatively as this solely addresses the role of static factors. Vigilance to factors affecting cord perfusion and vascular compromise, such as the mean arterial pressure (MAP), is imperative. Additionally, further studies should evaluate the role of positioning in the myelopathic patient and whether the steep Trendelenburg position, commonly used in robotic surgeries, contributes to spinal cord venous congestion and resultant cord ischemia in these patients given their baseline stenotic canal. This review illustrates the importance of having a heightened awareness of this common degenerative condition in our aging patient population, often a forgotten underlying medical comorbidity.

Acute Presentation of Vestibular Schwannoma Secondary to Intratumoral Hemorrhage: A Case Report and Literature Review.

BACKGROUND: Vestibular schwannomas (VS) are common slow-growing tumors that typically present with the insidious progression of unilateral hearing loss, tinnitus, vertigo, and gait imbalance. Clinically significant intratumoral acute hemorrhage is exceedingly rare and can present with the acute onset of symptoms, neurologic deterioration, and significant dysfunction of cranial nerves VII and VIII. We discuss a 40-year-old man who developed mild hearing loss and headaches over the course of a month before presenting with a large acutely hemorrhagic vestibular schwannoma. In addition, we review the current literature pertaining to this pathology. CASE PRESENTATION: A previously healthy 40-year-old man with a 1-month history of mild headaches, dizziness, and left-sided hearing loss, tinnitus, and facial numbness presented with the acute onset of severe headache, vomiting, complete left-sided hearing loss, and left-sided facial weakness. Computed tomography and magnetic resonance imaging revealed a 4.1 × 2.7 cm hemorrhagic mass in the left cerebellopontine angle most consistent with VS. The patient subsequently underwent a retrosigmoid craniotomy and resection of the tumor. Pathology was consistent with hemorrhagic VS. Imaging at 1-year follow-up demonstrated no residual or recurrent disease, and facial motor function had completely recovered. CONCLUSIONS: Histologically, vascular abnormalities and microhemorrhages are nearly ubiquitous across vestibular schwannomas and may contribute to cystic degeneration and rapid tumor growth. However, clinically significant hemorrhage is rarely encountered and is more commonly associated with more profound neurologic sequelae and cranial nerve VII dysfunction. Surgical resection at the time of presentation should be strongly considered to remove the risk of repeat hemorrhage and further deterioration. Our case represents a typical presentation and clinical course for a patient presenting with this rarely encountered pathology.

Lymphoma of the Optic Apparatus in an Immunocompetent Patient: A Case Report and Review of the Literature.

BACKGROUND: Primary optic apparatus involvement by lymphoma is an exceedingly rare entity, with only 3 cases previously reported in the literature. Whether this represents a distinct pathology, metastatic disease from an unidentified systemic lymphoma, or the first manifestation of evolving primary central nervous system lymphoma is not currently understood. CASE DESCRIPTION: We present a case of a young immunocompetent male with rapidly progressive visual loss who was found to have isolated lymphomatous involvement of the optic apparatus. We discuss the classification of the lesion, the clinical presentation, the diagnostic workup, and the visual and overall prognosis. Special consideration is given to the operative approach and selecting an appropriate site for biopsy based on the visual exam at the time of presentation. CONCLUSIONS: Primary optic nerve lymphoma is a rare disease that requires a systemic workup and a multidisciplinary approach to treatment.

Long-term outcomes of deep brain stimulation in severe Parkinson's disease utilizing UPDRS III and modified Hoehn and Yahr as a severity scale.

OBJECTIVES: Deep brain stimulation (DBS) is the surgical treatment of choice for moderate to severe Parkinson's Disease (PD). However, few studies have assessed its efficacy in severe PD as defined by the modified Hoehn and Yahr scale (HY). This study evaluates long-term and medication outcomes of DBS in severe PD. PATIENTS AND METHODS: We retrospectively collected the data of 15 patients from 2008 to 2014 with severe PD treated with DBS. Retrospective assessment with the modified Hoehn and Yahr scale and motor subset of the Unified Parkinson's Disease Rating Scale (UPDRS III) were used to objectively track severity and motor function improvement, respectively. Levodopa equivalence daily doses (LEDD), number of anti-PD medications and number of daily medication doses were used to measure improvements in medication burden. Data was evaluated using univariate analyses, one sample paired t-test, two sample paired t-test, and Wilcoxon signed-rank test. RESULTS: The mean post-operative follow-up was 44.63 months, average age at diagnosis and the average age at time of DBS was 51.3 years and 61.5 years, respectively, and the time from diagnosis to treatment was 13.2 years. Significant decreases were seen in UPDRS III scores (pre-op = 44.533; post-op = 26.13; p = 0.0094), LEDD (pre-op = 1679.34 mg; post-op = 837.48 mg; p = 0.0049), and number of daily doses (pre-op = 21.266; post-op 12.2; p = 0.0046). No significant decrease was seen in the number of anti-PD medications (pre-op = 3.8; post-op = 3.2; p = 0.16). CONCLUSION: Following DBS, severe PD patients demonstrated significant improvements in motor function and medication burden during long-term follow-up. We believe our results prove that DBS is efficacious in the management of severe PD, and that further research should follow to expand DBS criteria to include severe disease.

Suprasellar Epidermoid Cyst Originating from the Infundibulum: Case Report and Literature Review.

Epidermoid cysts account for a small fraction of intracranial brain tumors, most commonly found in the cerebellopontine angle and parasellar cisterns. Here we present a rare case of an epidermoid cyst located in the suprasellar region, specifically originating from the infundibulum. Only one additional case with an epidermoid cyst originating within the pituitary stalk has been previously reported in the literature. The patient in this case presented with headaches, diplopia and blurred vision without any endocrinopathy. The patient's pre-operative evaluation was significant for pseudotumor cerebri, hyponatremia, obesity, and a history of smoking; post-operative course was significant for neurogenic diabetes insipidus.

Use of MRI in diabetic lumbosacral radiculoplexus neuropathy: case report and review of the literature.

Diabetic lumbosacral radiculoplexus neuropathy is often confused with radiculopathy in the context of spinal degenerative disc disease including spinal stenosis. Accuracy in diagnosis may prevent unnecessary interventional procedures including selective nerve root blocks or epidural steroid injections or even surgery in selected cases. Our patient with known diabetes and lumbar disc disease presented with acute onset of pain in L5-S1 distribution of the left lower extremity. Initial MR imaging of the lumbar spine did not show sufficient structural changes to explain her symptomatology. An MR neurogram of the lumbosacral plexus revealed inflammation within the bilateral sciatic and femoral nerves; subsequent EMG demonstrated a generalized sensorimotor neuropathy but no evidence of plexopathy. To our knowledge, this is the first case report that utilized MR imaging of the pelvis to assist in the diagnosis of diabetic lumbosacral radiculoplexus neuropathy (DLRPN).

Evolution of Traumatic Parenchymal Intracranial Hematomas (ICHs): Comparison of Hematoma and Edema Components.

This study seeks to quantitatively assess evolution of traumatic ICHs over the first 24 h and investigate its relationship with functional outcome. Early expansion of traumatic intracranial hematoma (ICH) is common, but previous studies have focused on the high density (blood) component. Hemostatic therapies may increase the risk of peri-hematoma infarction and associated increased cytotoxic edema. Assessing the magnitude and evolution of ICH and edema represented by high and low density components on computerized tomography (CT) may be informative for designing therapies targeted at traumatic ICH. CT scans from participants in the COBRIT (Citicoline Brain Injury Trial) study were analyzed using MIPAV software. CT scans from patients with non-surgical intraparenchymal ICHs at presentation and approximately 24 h later (±12 h) were selected. Regions of high density and low density were quantitatively measured. The relationship between volumes of high and low density were compared to several outcome measures, including Glasgow Outcome Score-Extended (GOSE) and Disability Rating Score (DRS). Paired scans from 84 patients were analyzed. The median time between the first and second scan was 22.79 h (25%ile 20.11 h; 75%ile 27.49 h). Over this time frame, hematoma and edema volumes increased >50% in 34 (40%) and 46 (55%) respectively. The correlation between the two components was low (r = 0.39, p = 0.002). There was a weak correlation between change in edema volume and GOSE at 6 months (r = 0.268, p = 0.037), change in edema volume and DRS at 3 and 6 months (r = -0.248, p = 0.037 and r = 0.358, p = 0.005, respectively), change in edema volume and COWA at 6 months (r = 0.272, p = 0.049), and between final edema volume and COWA at 6 months (r = 0.302, p = 0.028). To conclude, both high density and low density components of traumatic ICHs expand significantly in the first 2 days after TBI. In our study, there does not appear to be a relationship between hematoma volume or hematoma expansion and functional outcome, while there is a weak relationship between edema expansion and functional outcome.

Reliability of the NINDS common data elements cranial tomography (CT) rating variables for traumatic brain injury (TBI).

BACKGROUND: Non-contrast head computer tomography (CT) is widely used to evaluate eligibility of patients after acute traumatic brain injury (TBI) for clinical trials. The NINDS Common Data Elements (CDEs) TBI were developed to standardize collection of CT variables. The objectives of this study were to train research assistants (RAs) to rate CDEs and then to evaluate their performance. The aim was to assess inter-rater reliability (IRR) of CDEs between trained RAs and a neurologist and to evaluate applicability of CDEs in acute and sub-acute TBI to test the feasibility of using CDE CT ratings in future trials and ultimately in clinical practice. The second aim was to confirm that the ratings of CDEs reflect pathophysiological events after TBI. METHODS AND RESULTS: First, a manual was developed for application of the CDEs, which was used to rate brain CTs (n = 100). An excellent agreement was found in combined kappas between RAs on admission and on 24-hour follow-up CTs (Iota = 0.803 and 0.787, respectively). Good IRR (kappa > 0.61) was shown for six CDEs on admissions and for seven CDEs on follow-up CTs. Low IRR (kappa < 0.4) was determined for five CDEs on admission and for four CDEs on follow-up CT. Combined IRR of each assistant with the neurologist were good on admission (Iota = 0.613 and 0.787) and excellent on follow-up CT (Iota = 0.906 and 0.977). Second, Principal Component Analysis (PCA) was applied to cluster the rated CDEs (n = 255) and five major components were found that explain 53% of the variance. CONCLUSIONS: CT CDEs are useful in clinical studies of TBI. Trained RAs can reliably collect variables. PCA identifies CDE clusters with clinical and biologic plausibility. ABBREVIATIONS: RA, research assistant; CT, Cranial Tomography; TBI, Traumatic Brain Injury; CDE, Common Data Elements; IRR, inter-rater reliability; PCA, Principal Component Analysis; GCS, Glasgow Coma Scale; R, rater; CI, confidence interval; CCC, Concordance correlation coefficient; IVH, Intraventricular haemorrhage; DCA, Discriminant Component analysis; SAH, Subarachnoid Haemorrhage.