A new classification of parasagittal bridging veins based on their configurations and drainage routes pertinent to interhemispheric approaches: a surgical anatomical study.

OBJECTIVE: Opening the roof of the interhemispheric microsurgical corridor to access various neurooncological or neurovascular lesions can be demanding because of the multiple bridging veins that drain into the sinus with their highly variable, location-specific anatomy. The objective of this study was to propose a new classification system for these parasagittal bridging veins, which are herein described as being arranged in 3 configurations with 4 drainage routes. METHODS: Twenty adult cadaveric heads (40 hemispheres) were examined. From this examination, the authors describe 3 types of configurations of the parasagittal bridging veins relative to specific anatomical landmarks (coronal suture, postcentral sulcus) and their drainage routes into the superior sagittal sinus, convexity dura, lacunae, and falx. They also quantify the relative incidence and extension of these anatomical variations and provide several preoperative, postoperative, and microneurosurgical clinical case study examples. RESULTS: The authors describe 3 anatomical configurations for venous drainage, which improves on the 2 types that have been previously described. In type 1, a single vein joins; in type 2, 2 or more contiguous veins join; and in type 3, a venous complex joins at the same point. Anterior to the coronal suture, the most common configuration was type 1 dural drainage, occurring in 57% of hemispheres. Between the coronal suture and the postcentral sulcus, most veins (including 73% of superior anastomotic veins of Trolard) drain first into a venous lacuna, which are larger and more numerous in this region. Posterior to the postcentral sulcus, the most common drainage route was through the falx. CONCLUSIONS: The authors propose a systematic classification for the parasagittal venous network. Using anatomical landmarks, they define 3 venous configurations and 4 drainage routes. Analysis of these configurations with respect to surgical routes indicates 2 highly risky interhemispheric surgical fissure routes. The risks are attributable to the presence of large lacunae that receive multiple veins (type 2) or venous complex (type 3) configurations that negatively impact a surgeon's working space and degree of movement and thus are predisposed to inadvertent avulsions, bleeding, and venous thrombosis.

Ring-shaped Dandy's superior petrosal vein.

BACKGROUND: Dandy's superior petrosal vein (SPV) anatomy is highly relevant for neurosurgeons. The SPV drains into the superior petrosal sinus (SPS), closely related to the trigeminal and internal auditory pores. METHOD: The archived enhanced MRI files of a male patient were studied. RESULTS: An infratentorial ring-shaped (RS) SPV was found on the petrosal surface of the right cerebellar hemisphere. It was inserted in the SPS above the internal auditory pore, postero-lateral to the trigeminal pore. The anterior arm of that venous ring received a delicate supratrigeminal plexus of veins from the pontine surface and continued as a single venous trunk on the cerebellar surface. CONCLUSION: Such previously unreported RS-SPV is of utmost importance to be identified before subtemporal transtentorial and retrosigmoid approaches for different neurosurgical reasons.

Preoperative assessment of the individual anatomy of the superior petrosal vein complex using balanced fast field echo magnetic resonance imaging.

BACKGROUND: Here, we sought to examine the validity and reproducibility of balanced fast field echo (bFFE) for assessing superior petrosal vein (SPV) complex (SPVC) anatomy. METHODS: Preoperative bFFE or equivalent scans and operative videos were studied and directly compared with regard to the individual anatomical features of SPVCs and their relation to the operative field. The anatomical details of the bFFE findings of the non-operated side (group 2) of all 50 patients were then reviewed, including the presence of petrosal-galenic anastomosis, and finally compared to the operated SPVCs (group 1). RESULTS: A complete correlation between bFFE and intraoperative findings was observed in 62% of cases and had a significant correlation with 3 Tesla magnet strength and higher pixel bandwidth (rbis = - 0.47; p = 0.005). The sensitivity and specificity of bFFE magnetic resonance imaging were 93.7 and 95.2%, respectively, for detecting an SPV disturbing the operative field, and 97.3% and 95% for a disturbing tributary, respectively. Each group had 50 SPVCs, with a total of 70 and 64 SPVs, 10 and 11 general SPVC configurations, as well as 29 and 28 different individual anatomical variations in groups 1 and 2, respectively. Both groups had 1-3 SPVs with a similar distribution of frequencies [Chi-square (4) = 27.56; p = 0.0145 (Fisher's exact test)]. The similarity of the general configurations was not statistically significant. The same four predominant configurations constituted 80% of the SPVCs in each group. The vein of the cerebellopontine fissure was most frequently found in 86% and 88% of cases, and a petrosal-galenic anastomosis was seen in 38% and 40% of groups 1 and 2, respectively. CONCLUSIONS: Individual SPVC variations are extensive. Good quality bFFE or equivalents are feasible for preoperative SPVC assessments. However, methods improving vascular visualization are recommended.

A Novel Direct Pathway of Dural Venous Outflow from the Basilar Venous Plexus via the Diploic Space of the Clivus.

BACKGROUND: The internal jugular vein (IJV) is the pre-eminent outflow of the dural venous sinuses (DVS) in the supine position, while the vertebral venous plexus (VVP) dominates venous outflow in the upright position. Emissary veins can also be an accessory pathway for this venous egress. To our knowledge, alternative dural venous sinus directly drainage via the diploic space has not been previously reported in the literature. METHODS: Ten fresh frozen adult cadavers underwent exposure of the basilar venous plexus. The entire plexus, still adhered to the underlying clivus, was removed with its underlying bone and submitted for histological examination following decalcification (Masson Trichrome, 5 µm slices). RESULTS: All specimens were found to have direct communication between the basilar venous plexus and underlying diploic space of the clivus i.e., no intermediate clival emissary vein. These were concentrated near the midline and were more numerous over the clivus near the junction of the occipital and sphenoid bones. The endothelium of the venous sinus was continuous at the opening into the diploic space and these openings ranged in size from 500 to 750 µm (mean 650 µm). CONCLUSIONS: An improved understanding of the cerebral venous drainage can assist clinicians and surgeons in recognizing normal, pathologic, and variant anatomy in this region. Based on our study, direct venous sinus (DVS) to diploic space drainage offers an additional pathway for venous egress from the intracranium. Therefore, removal of the dura over the clivus during various skull base procedures might be associated with increased venous bleeding from the basilar venous plexus on its deep surface where it interfaces with the clivus.

Revisiting the Tentorial Venous Sinuses: Anatomical and Histological Study.

BACKGROUND: Anatomical studies of the tentorial sinuses (TS) are scant, and to our knowledge, histological studies of this structure have not been reported. Therefore, we aim to better elucidate this anatomy. METHODS: In 15 fresh frozen, latex injected, adult cadaveric specimens, the TS were evaluated with microsurgical dissection and histology. RESULTS: The superior layer had a mean thickness of 0.22 mm, and the inferior layer had a mean thickness of 0.26 mm. Two types of TS were identified. Type 1 was a small intrinsic plexiform sinus with no obvious connections to the draining veins with gross examination. Type 2 was a larger tentorial sinus with direct connections to the bridging veins from the cerebral and cerebellar hemispheres. In general, type 1 sinuses were located more medially than type 2 sinuses. The inferior tentorial bridging veins drained directly into the TS along with connections to the straight and transverse sinuses. In 53.3% of specimens, superficial and deep sinuses were seen, with superior and inferior groups draining the cerebrum and cerebellum, respectively. CONCLUSIONS: We identified novel findings for the TS which can be considered surgically and when diagnosing pathology involves these venous sinuses.

A New Classification of the Anatomical Variations of Labbé's Inferior Anastomotic Vein.

(1) Background: The inferior anastomotic vein of Labbé (LV) courses on the temporal lobe, from the sylvian fissure towards the tentorium cerebelli and finishes at the transverse sinus (TS). The importance of the LV topography is related to skull base neurosurgical approaches. Based on the hypothesis of the existence of as yet unidentified anatomical possibilities of the LV, we aimed through this research to document the superficial venous topographic patterns at the lateral and inferior surfaces of the temporal lobe. (2) Methods: A retrospective cohort of 50 computed tomography angiograms (CTAs) of 32 males and 18 females was documented. (3) Results: Absent (type 0) LVs were found in 6% of cases. Anterior (temporal, squamosal-petrosal-mastoid, type 1) LVs were found in 12% of cases. LVs with a posterior, temporoparietal course (type 2) were found to be bilateral in 46% of cases and unilateral in 36% of cases. Type 3 LVs (posterior, parietooccipital) were found to be bilateral in 8% and unilateral in 32% of cases. In 24% of cases, duplicate LVs were found that were either complete or incomplete. A quadruplicate LV was found in a male case. On 78 sides, the LV drained either into a tentorial sinus or into the TS. (4) Conclusions: The anatomy of the vein of Labbé is variable in terms of its course, the number of veins and the modality of drainage; thus, it should determine personalized neurosurgical and interventional approaches. A new classification of the anatomical variations of Labbé's vein, as detected on the CTAs, is proposed here (types 0-3).

Anatomy of Intracranial Veins.

The cerebral venous system is complex and sophisticated and serves various major functions toward maintaining brain homeostasis. Cerebral veins contain about 70% of cerebral blood volume, have thin walls, are valveless, and cross seamlessly white matter, ependymal, cisternal, arachnoid, and dural boundaries to eventually drain cerebral blood either into dural sinuses or deep cerebral veins. Although numerous variations in the cerebral venous anatomic arrangement may be encountered, the overall configuration is relatively predictable and landmarks relatively well defined. A reasonable understanding of cerebral vascular embryology is helpful to appreciate normal anatomy and variations that have clinical relevance. Increasing interest in transvascular therapy, particularly transvenous endovascular intervention provides justification for practitioners in the neurosciences to acquire at least a basic understanding of the cerebral venous system.

Transcallosal Suprachoroidal Approach for a Small Third Ventricular Colloid Cyst.

Background and Introduction: The interhemispheric transcallosal approach provides an elegant pathway to access the lesions of the third ventricle. However, every step of this approach is fraught with hazards which must be negotiated delicately. A comprehensive knowledge of surgical anatomy coupled with technical skill is necessary for optimum surgical results. Objective: This video aims to address the surgical nuances of the suprachoroidal transcallosal approach while accessing the lesions around the foramen of Monro in the anterior and middle part of the third ventricle. Surgical Technique: A 16-year-old boy presented with worsening headaches with episodes of speech arrest and blank stare for 6 years, which had become more frequent over the past 4-5 months. Radiology showed a subcentimeteric colloid cyst at the foramen of monro. A transcallosal corridor was used to reach the foramen of monro, and the suprachoroidal access was adopted to uncover the colloid cyst and excise it completely preserving the deep veins. Results: The patient had uneventful recovery and radiology showed complete excision of the cyst. Conclusion: Transcallosal approach, being minimally invasive, exploits the natural extra-axial corridor (interhemispheric) obviating the need for a cortical incision. The suprachoroidal approach mitigates the risks of thalamostriate vein injury, basal ganglia stroke, and hemiparesis.

Optic Tract as an Upper Limit in Amygdalectomy: Microsurgical Study.

BACKGROUND: In surgeries involving resection of the amygdala, despite clear relations established with the medial, lateral, anterior, posterior, and inferior segments, the upper limit remains controversial. The optic tract (OT) has been anatomically considered as a good landmark immediately inferior to the striatopallidal region. This anatomic structure has barely been explored by microsurgical study, generating uncertainty about the exact relationship with the surrounding structures. OBJECTIVE: To describe the OT in its entire length through microsurgical study, showing its superior, inferior, medial, and lateral relationships and highlighting its value as a landmark in superior amygdala resection. METHODS: Microsurgical anatomic dissection of the OT, from its origin in the chiasm to the lateral geniculate nucleus was performed in 8 alcohol-fixed human hemispheres, showing its different segments and relations. Photographs were taken from different angles to facilitate surgical orientation. RESULTS: We performed a dissection of the OT, showing its position relative to caudate and hippocampal formations. We exposed the structures related to the OT superiorly (striatopallidal region and superior caudate fasciculus), inferiorly (head of the hippocampus, amygdala, anterior choroidal artery, perforating artery branch of the anterior choroidal artery, terminal stria, and basal vein), medially (internal capsule and midbrain), and laterally (temporal stem [uncinate and inferior fronto-occipital fascicle], anterior perforated substance, and superior caudate fasciculus). CONCLUSION: To date, there is a paucity of articles describing the anatomy of the OT from a neurosurgery perspective. In this study, we describe the microsurgical anatomic path of the OT, as a reliable upper limit landmark for amygdala resection.

Automated segmentation of multiparametric magnetic resonance images for cerebral AVM radiosurgery planning: a deep learning approach.

Stereotactic radiosurgery planning for cerebral arteriovenous malformations (AVM) is complicated by the variability in appearance of an AVM nidus across different imaging modalities. We developed a deep learning approach to automatically segment cerebrovascular-anatomical maps from multiple high-resolution magnetic resonance imaging/angiography (MRI/MRA) sequences in AVM patients, with the goal of facilitating target delineation. Twenty-three AVM patients who were evaluated for radiosurgery and underwent multi-parametric MRI/MRA were included. A hybrid semi-automated and manual approach was used to label MRI/MRAs with arteries, veins, brain parenchyma, cerebral spinal fluid (CSF), and embolized vessels. Next, these labels were used to train a convolutional neural network to perform this task. Imaging from 17 patients (6362 image slices) was used for training, and 6 patients (1224 slices) for validation. Performance was evaluated by Dice Similarity Coefficient (DSC). Classification performance was good for arteries, veins, brain parenchyma, and CSF, with DSCs of 0.86, 0.91, 0.98, and 0.91, respectively in the validation image set. Performance was lower for embolized vessels, with a DSC of 0.75. This demonstrates the proof of principle that accurate, high-resolution cerebrovascular-anatomical maps can be generated from multiparametric MRI/MRA. Clinical validation of their utility in radiosurgery planning is warranted.

Acute cerebral venous outflow obstruction during convexity meningioma resection.

BACKGROUND: Cerebral venous outflow obstruction involves idiopathic intracranial hypertension, and the most common related condition is dural venous sinus stenosis or, in other words, an obstruction of the dural venous sinuses. In these cases, the pathological process is often chronic, displays only mild symptoms, and rarely requires urgent surgical intervention. In this study, we present a unique case involving an acute cerebral venous outflow obstruction that occurred during meningioma resection that ultimately had catastrophic consequences. MATERIALS AND METHODS: The patient's preoperative imaging only revealed an unremarkable frontal convexity meningioma with an average diameter exceeding 8 cm. She was admitted for a scheduled right frontoparietal craniotomy for lesion resection. RESULTS: The patient's unique congenital dural venous sinus structure along with a non-surgical epidural hematoma both contributed to a catastrophic outcome, causing a progressive hemispheric encephalocele, significant blood loss, and wound closure difficulties. CONCLUSION: Neurosurgeons should place an additional focus on cerebral venous outflow patency during tumor resection, even if the tumor does not involve the transverse or sigmoid sinuses. It is well known that the tacking sutures play an essential role in preventing an epidural hematoma, but the procedure to mitigate hematomas occurring outside the surgical field of view is not fully recognized by neurosurgeons. If dural tacking sutures are placed after complete tumor resection, the prophylactic effect for preventing EDH in the non-surgical areas may not be guaranteed. Therefore, we strongly advocate for the tacking sutures to be accurately placed before dural incisions are made.

Transosseous Veins of the Temporal Bone: Connection Between Middle and Posterior Cranial Fossa Venous Structures.

BACKGROUND: The veins and dural venous sinuses of the skull base are important to understand in terms of imaging findings, diagnoses, and surgery. However, to date and to the best of our knowledge, the transosseous veins of the petrous part of the temporal bone have not been studied. METHODS: Ten latex-injected adult cadaveric specimens (20 sides) were dissected to identify the intraosseous and transosseous veins. The petrous part of the temporal bone was drilled away, and the petrous part of the internal carotid artery and the veins of the middle and posterior cranial fossa adjacent to the petrous part of the temporal bone were exposed. RESULTS: Transosseous veins traveling through the petrous part of the temporal bone were identified on all 20 sides. In general, these were most concentrated near the anterior and posterior parts of the petrous part of the temporal bone. Most traveled more or less vertically from the petrous ridge and related superior petrosal sinus internally through the petrous part of the temporal bone toward the inferior petrosal sinus or horizontally, uniting the veins of the floor of the middle cranial fossa with the veins of the posterior cranial fossa. These transosseous veins connected the veins in the middle cranial fossa with the veins of the posterior cranial fossa. Most (70%) of these transosseous veins were also found to have small connections to the internal carotid venous plexus. CONCLUSIONS: To the best of our knowledge, previous studies have not reported on transosseous veins of the temporal bone or described their anatomy of connecting the veins of the middle and posterior cranial fossae.

CT angiographic study of the cerebral deep veins around the vein of Galen.

Research on the anatomy of cerebral deep veins (CDVs) around the vein of Galen (VG) is very important and has fundamental clinical significance. Large-scale anatomical studies of CDVs using computed tomography angiography (CTA) are rarely reported. A retrospective study of the CDVs around the VG was conducted in Chinese patients of Han nationality. One hundred cases were included in the final analysis. The patients were aged from 17 to 78 years (mean: 42.3 years). Also, 46% of the patients were female. The diameter of the internal cerebral vein (ICV) at its beginning and termination points ranged from 0.4 to 2.8 mm (1.49 ± 0.39 mm) and 0.4 to 3.5 mm (2.05 ± 0.47 mm), respectively. There was statistical significance regarding the diameter of the ICV at its beginning and termination points (P <0.01). The ICV length ranged from 28.5 to 47.9 mm (36.86 ± 3.74 mm). The length of the straight sinus (SS) ranged from 30.2 to 57.8 mm (43.6 ± 6.37 mm). The length of the VG ranged from 1.5 to 41.8 mm (9.30 ± 4.76 mm). The angle at the VG and SS transition area ranged from 25.4 to 110.6° (77.2 ± 18.0°). This study was a meaningful attempt to conduct anatomical research of CDVs using CTA. Preoperative familiarity with the normal venous structure and its variation around the VG would be helpful for endovascular treatment.

Bridging veins of the cerebellum: a magnetic resonance imaging study.

PURPOSE: To date, no study has yet explored the bridging veins (BVs) of the cerebellum using neuroimaging modalities. Therefore, this study aimed to characterize them using magnetic resonance imaging (MRI). METHODS: A total of 90 patients with intact cerebellar hemispheres and intracranial dural sinuses underwent thin-sliced, contrast-enhanced MRI. RESULTS: The BVs were classified into six routes based on the draining pattern into the dural sinuses. The superior vermian vein emptying into the straight sinus was delineated in 100% of the patients. The inferior vermian vein emptying into the confluence of the sinuses was identified in 66.7% of the patients. The inferior hemispheric and cerebellar cortical veins emptying into the transverse sinus were identified in 54.4% and 26.7% of the patients, respectively. The inferior vermian and cerebellar cortical veins emptying into the straight sinus were identified in 77.8% and 12.2% of the patients, respectively. The cerebellar cortical vein emptying into the tentorial sinus was identified in 83.3% of the patients; it was delineated on 54 sides with an average number per right hemisphere of 1.9 and 63 sides with an average number per left hemisphere of 2. The pontine-trigeminal and anterior hemispheric veins emptying into the superior petrosal sinus were identified in 42.2% of the patients. CONCLUSIONS: The BVs of the cerebellum can be classified into six distinct routes. Radiological classification may be useful for understanding the drainage pattern of the cerebellum.

Cortical and bridging veins of the upper cerebral convexity: a magnetic resonance imaging study.

PURPOSE: There is no study exploring the cortical veins (CVs) and connecting bridging veins (BVs) with neuroimaging modalities. The present study aimed to characterize these veins of the upper cerebral convexity. METHODS: A total of 89 patients with intact cerebral hemispheres and covering meninges underwent thin-sliced, contrast magnetic resonance imaging (MRI). In addition, three injected specimens were dissected in this study. RESULTS: In cadaver dissection, the BVs were observed to course in the arachnoid sheaths, suspended from the dura mater. The medial parts of the BVs, located near the superior sagittal sinus (SSS)-BV junction site, were occasionally exposed subdurally. The CVs were formed by venous channels arising from the cerebral gyri and those emerging from the sulci. On MRI, the CVs and connecting BVs were identified in the medial and latera convexity areas and medial surface of the cerebrum. These veins were highly variable in number, thickness, length, course, and distribution. In the medial convexity area, the CVs arising from the gyri were identified in 58% of patients, while they were found only in 11% of patients in the lateral convexity area. CONCLUSION: In the medial convexity area, involving the parasagittal region, the CVs connect more densely with the BVs that may predispose to injury during neurosurgical procedures. Mechanical impact exerted the area, diameter of the veins in the craniocaudal direction, and number of venous afferences may affect the SSS-BV junctional region in an indirect manner and lead to the development of acute subdural hematoma.

The Anatomy of the Convergence of Major Deep Cerebral Veins in the Pineal Region: A Computed Tomography Angiography Study.

BACKGROUND: The anatomy of the veins in the pineal region is one of the most complex areas in the brain because all major deep cerebral veins converge there: the internal cerebral veins (ICVs), the great cerebral vein of Galen (GV), the basal veins (BVs), and the internal occipital veins (IOVs). The aim of this study was to comprehensively describe the anatomy of the veins in the pineal region using computed tomography angiography. METHODS: Head computed tomography angiography scans of 250 adult Polish patients were evaluated. We assessed the location of the junction of 2 ICVs and the presence of a narrowing of the GV and arachnoid granulation at the GV-straight sinus junction. We evaluated the presence, appearance, and termination of the BV, and the presence and termination of the IOV. RESULTS: The study showed that 2 ICVs usually converged posterior to the splenium of the corpus callosum (62.4%). Narrowing of the BV was observed in 51.2% of patients, and the arachnoid granulation was found in 25.2%. The 3 segments of the BV were well visualized in 66% of the studied hemispheres. The BV flowed into the GV in 34.8% of the hemispheres. The IOV was present in 90.2% of the hemispheres and terminated medially in 84.5%. CONCLUSIONS: Because an injury to major deep cerebral veins may result in severe postoperative neurologic deficits, it is essential for neurosurgeons to be familiar with both normal and variant patterns of veins in the pineal region.

Venous anatomy of the infratentorial compartment.

Approximately 7%-12% of all intracranial meningiomas are located in the posterior fossa (PF), a region which contains-among many other critical neurovascular structures-numerous major veins and sinuses draining blood away from the PF structures. There is a growing body of evidence indicating that venous sacrifice or injury during surgery are linked to serious postoperative complications-which may lead to significant morbidity and mortality. Thus, it is of paramount importance that clinicians charged with the preoperative, surgical, and postoperative care of patients undergoing treatment for meningioma are familiar with the general anatomy of the PF veins, as well as their structural nuances and drainage variations. The present chapter surveys the relevant anatomy in a manner that aims to be useful for an interdisciplinary team of clinicians and concludes with a discussion of emerging imaging technologies that may assist them in their clinical decision-making.

Pediatric otitic hydrocephalus: Report of two unusual cases and literature review.

Otitic hydrocephalus (OH) comprises a form of benign intracranial hypertension, which is secondary to otogenic lateral sinus thrombosis (LST). Only a small percentage of the patients with otogenic LST go into developing OH, and this may be associated with the multiplicity of anatomic variations of the cerebral venous drainage pathways. We present two pediatric cases of OH, along with a comprehensive review of the relevant literature. Both cases discussed in this article had concomitantly a rather rare anatomical variation; a high-riding, dehiscent jugular bulb, which might have played a role in the development of their clinical syndrome. The pediatric population with this particular imaging finding should receive special attention. Clinical implications of this concurrence are fitly discussed.

Mapping the Fine-Scale Organization and Plasticity of the Brain Vasculature.

The cerebral vasculature is a dense network of arteries, capillaries, and veins. Quantifying variations of the vascular organization across individuals, brain regions, or disease models is challenging. We used immunolabeling and tissue clearing to image the vascular network of adult mouse brains and developed a pipeline to segment terabyte-sized multichannel images from light sheet microscopy, enabling the construction, analysis, and visualization of vascular graphs composed of over 100 million vessel segments. We generated datasets from over 20 mouse brains, with labeled arteries, veins, and capillaries according to their anatomical regions. We characterized the organization of the vascular network across brain regions, highlighting local adaptations and functional correlates. We propose a classification of cortical regions based on the vascular topology. Finally, we analysed brain-wide rearrangements of the vasculature in animal models of congenital deafness and ischemic stroke, revealing that vascular plasticity and remodeling adopt diverging rules in different models.

Individual variations of the superior petrosal vein complex and their microsurgical relevance in 50 cases of trigeminal microvascular decompression.

BACKGROUND: We investigated the understudied anatomical variations of the superior petrosal vein (SPV) complex (SPVC), which may play some role in dictating the individual complication risk following SPVC injury. METHODS: Microvascular decompressions of the trigeminal nerve between September 2012 and July 2016. All operations utilized an SPVC preserving technique. Preoperative balanced fast field echo (bFFE) magnetic resonance imaging, or equivalent sequences, and operative videos were studied for individual SPVC anatomical features. RESULTS: Applied imaging and operative SPVC anatomy were described for fifty patients (mean age, 67.18 years; female sex and right-sided operations, 58% each). An SPVC component was sacrificed intentionally in 6 and unintentionally in only 7 cases. Twenty-nine different individual variations were observed; 80% of SPVCs had either 2 SPVs with 3 or 1 SPV with 2, 3, or 4 direct tributaries. Most SPVCs had 1 SPV (64%) and 2 SPVs (32%). The SPV drainage point into the superior petrosal sinus was predominantly between the internal auditory meatus and Meckel cave (85.7% of cases). The vein of the cerebellopontine fissure was the most frequent direct tributary (86%), followed by the pontotrigeminal vein in 80% of SPVCs. Petrosal-galenic anastomosis was detected in at least 38% of cases. At least 1 SPV in 54% of the cases and at least 1 direct tributary in 90% disturbed the operative field. The tributaries were more commonly sacrificed. CONCLUSIONS: The extensive anatomical variation of SPVC is depicted. Most SPVCs fall into 4 common general configurations and can usually be preserved. BFFE or equivalent sequences remarkably facilitated the intraoperative understanding of the individual SPVC in most cases.