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Introduction: We present a case of a concealed intradural lumbar disc herniation following a previous discectomy with adhesions of the ventral dura to the posterior longitudinal ligament. Case Presentation: A 40-year-old Asian male with a lumbar discectomy 2 years ago presented to our emergency department with over the last few days rapidly progressing neurological symptoms of the lower limbs. The patient was admitted and MRI was performed on an emergency basis. Due to severe pain, and as a result the patient inability to lie down to complete the MRI examination, the MRI scan was incomplete. However, it showed an occupying mass at the level L4/5 with suspected recurrent disc herniation. Intraoperative only a small herniation was found. A new MRI, performed shortly after the 1st surgery, revealed an intradural herniation that could be addressed by microscopic durotomy and sequestrectomy. Because of persisting weakness and pain a new MRI scan was done and revealed a recurrent intradural hernia proximal to the durotomy. Revision surgery was indicated and performed successfully. The 6 months follow-up MRI scan revealed no signs of recurrence. The clinical examination, 6 months postoperatively, showed almost complete remission of the preoperative weakness and pain with restoration of the walking ability. Discussion: Most literature addressing the pathophysiology of intradural lumbar disc herniation are cadaveric studies. Currently only few case reports or series discuss this pathology. Different theories including ‘mechanical compression’ and ‘adhesions’ theories have been discussed. A solid proof couldn’t be provided. Our patient had a previous discectomy at the same segment two years ago. The MRI scans could clearly show scar tissue on this level with a direct connection of the lumbar disc to the intradural compartment. We believe that extradural adhesions provided an access, through which disc fragments could migrate intradurally. Conclusion: Intradural disc herniation is a rare presentation and its diagnosis can be challenging. With rapidly progressing neurological symptoms and positive history for previous spinal surgery, intradural disc herniation should be kept in mind as an important differential diagnosis. Careful postoperative monitoring, and possibly early follow-up MRI, is needed to avoid missing a recurrent herniation or missed intradural disc fragments.

Object With the introduction of intraoperative CT (iCT) scanning, neurosurgeons can now obtain images of the brain during surgery, offering the possibility of intraoperative resection control and monitoring of potential intraoperative complications. The combination of iCT with neuronavigation makes it possible to update the reference scans intraoperatively when necessary. However, the headholder pins normally used for iCT scanning still show artifacts. In the present study, new polymer pins, producing nearly no artifacts in laboratory tests, are compared with the usual pins with regard to their mechanical and artifact behavior to evaluate their potential use in the clinical routine. Methods Pins made of different materials (titanium, Macor, silicon nitride, zirconium oxide, sapphire, polyetheretherketone, and polyparaphenylene copolymer) were used for the fixation of 10 cadaveric heads. Special force sensors measured the fixation pressure of the pins, and histological analysis revealed the penetration depth. Computed tomography scans of a head phantom, fixed with the different pins, were obtained to reveal artifact behavior. Results All pins were biocompatible. Pins did not differ significantly in fixation pressures and mechanical behavior. Penetration depths were comparable (maximum 1.4 mm) and did not cause opening of the diploe. Polymer pins made of polyparaphenylene showed the best results in artifact behavior in CT scans. Conclusions The authors' results demonstrate that the new polymer pins are comparable in their mechanical behavior to the usual pins but superior in artifact behavior. Therefore, their use in the clinical routine of iCT scanning will be beneficial for the surgeon.

Traumatic brain injury (TBI) consists of two phases: an immediate phase in which damage is caused as a direct result of the mechanical impact; and a late phase of altered biochemical events that results in delayed tissue damage and is therefore amenable to therapeutic treatment. Because the molecular mechanisms of delayed post-traumatic neuronal cell death are still poorly understood, we investigated whether apoptosis-inducing factor (AIF), a pro-apoptotic mitochondrial molecule and the key factor in the caspase-independent, cell death signaling pathway, plays a causal role in neuronal death following TBI. Using an in vitro model of neuronal stretch injury, we demonstrated that AIF translocated from mitochondria to the nucleus of neurons displaying axonal disruption, chromatin condensation, and nuclear pyknosis in a caspase-independent manner, whereas astrocytes remained unaffected. Similar findings were observed following experimental TBI in mice, where AIF translocation to the nucleus coincided with delayed neuronal cell death in both cortical and hippocampal neurons. Down-regulation of AIF in vitro by siRNA significantly reduced stretch-induced neuronal cell death by 67%, a finding corroborated in vivo using AIF-deficient harlequin mutant mice, where secondary contusion expansion was significantly reduced by 44%. Hence, our current findings demonstrate that caspase-independent, AIF-mediated signaling pathways significantly contribute to post-traumatic neuronal cell death and may therefore represent novel therapeutic targets for the treatment of TBI.

Cerebral cavernous malformations (CCM) are common hamartous dysplasias characterized by abnormally dilated vascular channels. CCM mostly occur sporadically, and multiple occurrence of CCM is highly suggestive of a genetic origin of the disorder. Typical clinical symptoms are seizures, hemorrhages, focal neurological deficits, and headaches. Three genes have so far been described that are responsible for most cases of familial CCM and more than half of the sporadic cases with multiple CCM (CCM1-3). The coincidence of CCM and other vascular anomalies has been described before. The present review discusses the association of CCM with mesenchymal anomalies, with special emphasis on the possible common pathogenetic pathway for CCM and atrial myxomas. An illustrative case is presented in which CCM occurred together with different dysplasias (multiple CCM, liver cavernoma, and cardiac atrial myxoma), which are all thought to arise from abnormal mesenchymal cell differentiation processes.

Modern magnetic resonance imaging (MRI) techniques have improved the planning of surgery to remove lesions in or around the frontal lobe. Since MRI-based morphometric analyses of the anterior part of the frontal lobe and the central region as part of it have not yet been performed, the present study was undertaken to obtain relative normative morphometric data. Median sagittal MRI scans from 53 magnetization prepared rapid acquisition gradient echo (MPRAGE) sequences of individual brains without pathological lesions were analyzed. The AC-PC line (anterior commissure-posterior commissure line) with vertical lines through the AC and PC were chosen as reference lines. Measurements of the anterior part of the frontal lobe included distances between different landmarks (frontal pole, tuberculum sellae, AC, outer point and inner surface of the genu of the corpus callosum, and the cortex at this level). For the measurements around the central region distances were obtained from the following landmarks: coronal suture, central sulcus, marginal sulcus, intersection point of the vertical line through the PC with the cortex, and PC. Knowledge of these distances will allow exact planning of surgical approaches to the anterior part of the frontal lobe, for example, the subfrontal or anterior interhemispheric approach and surgery around the central region.

The cerebral venous outflow consists of the superficial system and the deep draining system. The deep one drains the areas of the great vein of Galen, the two basal veins of Rosenthal, and their tributaries. Simultaneous obstruction of these veins can effect great harm. In the case of obstruction of the vein of Galen, the basal vein can ensure the venous outflow. Therefore, attention should be paid to anastomoses between the basal vein and the infratentorial venous system. The lateral mesencephalic vein (LMV) is the most important anastomosis between the supra- and infratentorial system linking the basal vein to the superior petrosal sinus. Since microanatomical studies concerning this vein have received less attention the aim of the present study was to visualize the course of this vein, its junction with the basal vein, its tributaries and its relationship with neural structures. Fifty-two cadaveric hemispheres were examined under the operating microscope. The LMV could be identified in all cases, with a mean diameter of 1.07 mm. Thorough understanding of the microanatomy of the LMV is crucial to avoid brain damage due to venous infarction during surgery, and its preservation could ensure deep venous outflow in the case of obstruction of the vein of Galen.

With the introduction of intraoperative CT (iCT) scanning, neurosurgeons can now obtain images of the brain during surgery, offering the possibility of intraoperative resection control and monitoring of potential intraoperative complications. The combination of iCT with neuronavigation makes it possible to update the reference scans intraoperatively when necessary. However, the headholder pins normally used for iCT scanning still show artifacts. In the present study, new polymer pins, producing nearly no artifacts in laboratory tests, are compared with the usual pins with regard to their mechanical and artifact behavior to evaluate their potential use in the clinical routine.Pins made of different materials (titanium, Macor, silicon nitride, zirconium oxide, sapphire, polyetheretherketone, and polyparaphenylene copolymer) were used for the fixation of 10 cadaveric heads. Special force sensors measured the fixation pressure of the pins, and histological analysis revealed the penetration depth. Computed tomography scans of a head phantom, fixed with the different pins, were obtained to reveal artifact behavior.All pins were biocompatible. Pins did not differ significantly in fixation pressures and mechanical behavior. Penetration depths were comparable (maximum 1.4 mm) and did not cause opening of the diploe. Polymer pins made of polyparaphenylene showed the best results in artifact behavior in CT scans.The authors' results demonstrate that the new polymer pins are comparable in their mechanical behavior to the usual pins but superior in artifact behavior. Therefore, their use in the clinical routine of iCT scanning will be beneficial for the surgeon.

Object The mesencephalic veins drain crucial brainstem areas. Due to the narrowness of the tentorial notch, these veins can become obstructed as a result of herniation or surgery, leading to hemorrhage and severe consequences for the patient. There is little in the literature about the mesencephalic veins. The aim of this study was to perform an exact analysis of their microanatomy. Methods Fifty-two cadaveric hemispheres were examined under an operating microscope, and measurements were made with a digital caliper. The authors focused on the basal vein (BV), pontomesencephalic vein (PMV), peduncular vein (PV), lateral mesencephalic vein (LMV), and other smaller veins. The PMV was identified in 84.6% of specimens (mean diameter 0.54 mm); the PV, in 86.5% (mean diameter 0.86 mm); and the LMV, in 100% (mean diameter 1.07 mm). Four types of LMV were identified on the basis of the vein's course. Other smaller veins were also differentiated according to whether they drained mainly the cerebral peduncle, the lemniscal trigone, or the tectum. These veins and their junctions with other veins were depicted. Conclusions A thorough understanding of the microanatomy of the mesencephalic veins is crucial in brainstem surgery in order to avoid brain damage due to venous infarction and subsequent edema. Because knowledge of the course, variations, and outflow system of these veins could improve surgical outcome, they warrant special attention during surgery.

Acute and chronic neurodegeneration, for example, following brain injury or Alzheimer's disease, is characterized by programmed death of neuronal cells. The present study addresses the role and interaction of p53- and NF-kappaB-dependent mechanisms in delayed neurodegeneration following traumatic brain injury (TBI). After experimental TBI in mice p53 rapidly accumulated in the injured brain tissue and translocated to the nucleus of damaged neurons, whereas NF-kappaB transcriptional activity simultaneously declined. Post-traumatic neurodegeneration correlated with the increase in p53 levels and was significantly reduced by the selective p53 inhibitor pifithrin-alpha (PFT). Strikingly, this protective effect was observed even when PFT treatment was delayed up to 6 h after trauma. Inhibition of p53 activity resulted in the concomitant increase in NF-kappaB transcriptional activity and upregulation of NF-kappaB-target proteins, for example X-chromosomal-linked inhibitor of apoptosis (XIAP). It is interesting to note that inhibition of XIAP abolished the neuroprotective effects of PFT in cultured neurons exposed to camptothecin, glutamate, or oxygen glucose deprivation. In conclusion, delayed neuronal cell death after brain trauma is mediated by p53-dependent mechanisms that involve inhibition of NF-kappaB transcriptional activity. Hence, p53 inhibition provides a promising approach for the treatment of acute brain injury, since it blocks apoptotic pathways and concomitantly triggers survival signaling with a therapeutic window relevant for clinical applications.

OBJECTIVE: The tentorial notch can be contained within a transversal line made in front of the cerebral peduncles and another line through the posterior border of the quadrigeminal plate into the anterior, middle and posterior parts. Different approaches to the tentorial incisura have been established. The subtemporal approach represents one of those options. Since morphometrical analyses of this approach in this region have not yet been performed, the aim of the present study was to measure the surgical corridor along these borders. METHODS: Fifty-three magnetization prepared rapid acquisition gradient echo-sequences of individual brains without pathological lesions were analyzed. For this study, an axial section along the pontomesencephalic sulcus and two coronal sections along the above-described borders were measured using a program specially written by one of the coauthors to obtain various parameters. A triangle circumscribing the surgical corridor was delimited by exactly defined anatomic landmarks for the coronal section, and the depths of the temporal lobe at the incisural borders were measured for the axial section. RESULTS: Various data are given concerning the surgical corridor of a subtemporal approach to the tentorial incisura. The different shapes of this corridor to the incisural region were recorded. According to our measurements, four different types of the temporal lobe could be differentiated. CONCLUSION: Knowledge of these distances and various contours of the path is crucial to avoid brain damage during retraction or manipulation. The curvature of the floor of the middle cranial fossa is highly variable and thus determines the surgical path chosen.