The Top 100 Most Cited Journal Articles on Hydrocephalus.

Hydrocephalus represents a significant burden of disease, with more than 383,000 new cases annually worldwide. When the magnitude of this condition is considered, a centralized archive of pertinent literature is of great clinical value. From a neurosurgical standpoint, hydrocephalus is one of the most frequently treated conditions in the field. The focus of this study was to identify the top 100 journal articles specific to hydrocephalus using bibliometric analysis. Using the Journal of Citation Report database, 10 journals were identified. The Web of Science Core Collection was then searched using each journal name and the search term "hydrocephalus." The results were ordered by "Times Cited" and searched by the number of citations. The database contained journal articles from 1976 to 2021, and the following variables were collected for analysis: journal, article type, year of publication, and the number of citations. Journal articles were excluded if they had no relation to hydrocephalus, mostly involved basic science research, or included animal studies. Ten journals were identified using the above criteria, and a catalog of the 100 most cited publications in the hydrocephalus literature was created. Articles were arranged from highest to lowest citation number, with further classification by journal, article type, and publication year. Of the 100 articles referenced, 38 were review articles, 24 were original articles, 15 were comparative studies, 11 were clinical trials, six were multi-center studies, three were cross-sectional, and three were case reports with reviews. Articles were also sorted by study type and further stratified by etiology. If the etiology was not specified, studies were instead subcategorized by treatment type. Etiologies such as aqueductal stenosis, tumors, and other obstructive causes of hydrocephalus were classified as obstructive (n=6). Communicating (n=15) included idiopathic, normal pressure hydrocephalus, and other non-obstructive etiologies. The category "other" (n=3) was assigned to studies that included etiologies, populations, and/or treatments that did not fit into the classifications previously outlined. Through our analysis of highly cited journal articles focusing on different etiologies and the surgical or medical management of hydrocephalus, we hope to elucidate important trends. By establishing the 100 most cited hydrocephalus articles, we contribute one source, stratified for efficient referencing, to facilitate clinical care and future research on hydrocephalus.

Bihemispheric posterior inferior cerebellar artery in a cadaver with Chiari I malformation.

Typically, patients with Chiari I malformations (CM I) do not have other intracranial anatomical variations, especially vascular derailments. Here, we report the findings of a cadaveric specimen found to have CM I and cerebellar tonsils supplied by a single posterior inferior cerebellar artery (PICA) i.e., a bihemispheric PICA. An adult male cadaver was found to have CM I. It was also noted that the left PICA descended inferiorly to the level of C1 and that there was absence of the right PICA. The territory of the right PICA was supplied by the left PICA. The tonsillar component of the left PICA gave rise to a branch that crossed to the right inferior cerebellum and herniated cerebellar tonsil. A bihemispheric PICA is very rare. To our knowledge, this is the first report of this vascular variation in combination with CM I. Such a variation should be kept in mind, especially during posterior fossa decompression for symptomatic CM I as unilateral PICA injury could have catastrophic results.

Anatomical study of the internal carotid venous plexus: new findings with application to skull base surgery.

OBJECTIVE: The venous plexus (internal carotid venous plexus) surrounding the petrous part of the internal carotid artery (ICAp) is said to be one drainage pathway of the cavernous sinus. These veins have many potential clinical implications including iatrogenic hemorrhage during surgical approaches to the skull base and carotid-cavernous fistulas. Because there are few morphological data about this venous plexus at the skull base, this descriptive/quantitative study was performed to elucidate its anatomy. METHODS: Six latex-injected cadaveric heads (twelve sides) were dissected via a superior craniotomy approach in which the ICAp was exposed by drilling away the overlying bone. A venous plexus surrounding parts of the ICAp in all sides was documented along with the positions of its major tributaries and their connections. RESULTS: The veins were most concentrated near the junction of the ICAp and the cavernous part of the internal carotid artery, and usually along the medial and lateral sides of the ICAp. Tributaries included branches joining the basilar venous plexus posteriorly and branches joining the veins surrounding the foramen ovale anteriorly. CONCLUSION: Detailed knowledge of the anatomy of this venous plexus surrounding the ICAp is useful for interpreting imaging of the skull base and valuable for surgeons operating in this part of the cranium.

Can anatomical feasibility studies drive neurosurgical procedures and reach patients faster than traditional translational research?

Often, surgical techniques are practiced and studied in the anatomy laboratory. Occasionally, new surgical methods are developed with cadaveric anatomical studies. Some cadaveric feasibility studies, if published, might go on to be used by surgeons from around the world for improved patient care. Herein, we review our experience with 37 published anatomical feasibility studies over an 18-year period (2002-2020) and analyze the literature for published examples of surgical application of these same anatomical studies. We found that, for cadaveric anatomical feasibility studies within 7 years of their publication date, approximately 22% will be used in neurosurgery with the clinical applications published. Of these studies awarded clinical citation within 7 years of publication, the median time to that citation was approximately 3.4 years. As the average time for translational research to reach patient care is 17 years, cadaveric anatomical studies in this series reached patient care much sooner than traditional translational research. Cadaveric anatomical studies, based on our experience, can drive neurosurgical procedures.

Detethering the superficial temporal artery: Application to tension free superficial temporal artery-middle cerebral artery bypasses.

Extracranial-intracranial bypass has been shown to be effective in the surgical treatment of moyamoya disease, complex aneurysms, and tumors that involve proximal vasculature in carefully selected patients. Branches of the superficial temporal artery (STA) are used commonly for the bypass surgery; however, an appropriate length of the donor vessel must be harvested to avoid failure secondary to anastomotic tension. The goal of this cadaveric study was to investigate quantitatively operative techniques that can increase the STA length available to facilitate tension-free STA-middle cerebral artery (MCA) bypass. We conducted a cadaveric study using a total of 16 sides in eight cadavers. Measurements of the STA trunk with its frontal branch (STAfb) were taken before and after skeletonization and detethering of the STA with the STAfb and mobilization of the parietal branch of the STA. A final measurement of the STA with the STAfb was taken for the free length gained toward visible proximal cortical branches of the MCA. Paired student's t-tests were used to compare the mean length before and after mobilization and unpaired t-tests to analyze according to laterality. The mean length of the STA with the STAfb was 9.0 cm prior to modification. After skeletonization and mobilization, the mean lengths increased significantly to 10.5 and 11.3 cm, respectively (p < 0.05). Especially in the cases that had the coiled and tortuous STA, skeletonization was considerably effective to increase the length of the STA with the STAfb. After simulating a bypass by bringing the STAfb to the recipient MCA site, the mean extended length of the STA with the STAfb was 3.0 cm. There were no statistically significant differences between sides in all measurements. We report a significant increase in the mean STA length available (3.0 cm) following skeletonization and mobilization. Clinical applications of the extended length of the STA with the STAfb may facilitate tension-free STA-MCA bypasses and improve outcomes. Further studies are needed in a clinical context.

Novel Use of Nerve Branch to Sartorius as Donor for Intrapelvic Neurotization of the Sciatic Nerve and Its Contributions.

BACKGROUND: Sciatic nerve injuries are relatively infrequent but extremely disabling for the patient. As injury to this nerve is relatively infrequent, there is little about its repair in the literature, especially within the pelvis. METHODS: Twelve adult embalmed cadavers (24 sides) underwent exposure of the anteromedial thigh, inguinal region, and pelvic cavity. The sartorius muscle was identified in the anterior thigh, and its nerve branches from the femoral nerve were isolated and traced proximally to the femoral nerve trunk. The isolated sartorius nerve branches were further traced to the pelvic part of the femoral nerve. Next, the lumbosacral plexus was dissected on the posterior aspect of the pelvis so that its constituent parts were seen and followed distally to also visualize the most proximal part of the sciatic nerve. The previously dissected nerve branches to sartorius were then transposed to these constituent parts, and the ability for a tension-free anastomosis between these 2 nerves was evaluated. RESULTS: The branches ranged in diameter from 1.89 to 3.1 mm (2.88 mm). The average length of the nerves was 17.3 cm. Transposition of these branches to all ventral rami of the lumbosacral plexus in the pelvis and proximal sciatic (intrapelvic) nerve was possible on all cadaveric sides. CONCLUSIONS: Our cadaveric study found that nerve branches to the sartorius muscle can be transposed intrapelvically to the lumbosacral plexus and could provide tension-free anastomoses for neurotization procedures in patients with nerve injury.

An anatomical model for studying cerebellar tonsillar herniation related to raised intracranial pressure.

Brain herniation is one of the most feared complications of many neurological pathologies. However, current understanding of the mechanisms behind brain herniation syndromes is poor. By investigating the correlations between raised intracranial pressure (ICP) and herniation of the cerebellar tonsils, we hope to develop a model that can be used to study intracranial fluid dynamics and its effects on brain tissue. This will facilitate evaluation of patients with elevated ICP and development of novel treatments including surgical approaches for decompressing the posterior cranial fossa and upper cervical spine. A standard suboccipital surgical approach was used to expose the foramen magnum and observe movements of the cerebellar tonsils in fresh cadavers. A urinary Foley catheter balloon in the parietal extradural space was used to simulate a mass effect while ICP was monitored. The baseline anatomy differed widely among the cadaver specimens. However, and overall, we found that as ICP rises, the cerebellar tonsils descend through the foramen magnum at a rate of 0.3 mm per 1 mmHg increase in ICP. A mean descent of 6.2 mm was observed for a mean ICP increase of 17 mmHg. In this cadaveric study, we present a method and model for exploring brain herniation syndromes in the context of ICP changes. This could allow for further models to study the effects of other neuropathologies on the cerebellar tonsils, including posterior cranial fossa mass lesions and cerebellar hemorrhage.

Anatomical Study of the Posterior Spinal Artery Branches to the Medulla Oblongata.

BACKGROUND: The posterior spinal arteries (PSAs), branches of the intracranial segment of the vertebral artery or posterior inferior cerebellar artery, run bilaterally along the spinal cord and are integral to the blood supply primarily to the posterior one third of this structure. However, a less well-described distribution of the PSAs is their supply to the posterior medulla. The purpose of this study is to examine the medullary branches of the PSA anatomically. METHODS: We conducted a cadaveric study to evaluate for branches of the PSA supplying the medulla oblongata. RESULTS: All 14 sides had medullary branches arising from the PSAs. The average number of branches supplying the medulla oblongata on each side was 6. Most of these branches traveled laterally to anastomose with medullary branches arising from the anterior spinal artery. Additionally, lateral and ascending branches were noted. CONCLUSIONS: Physicians who interpret imaging of the craniocervical junction, in particular arteriograms, should be aware of ascending medullary branches arising from the anterior spinal artery. Additionally, neurosurgeons operating this region must be careful in dissecting over the posterior medulla and manipulating the cerebellar tonsils, as in telovelar approaches to the fourth ventricle, in order to avoid iatrogenic injury to these vessels. Additionally, variable stroke patterns involving the vertebral artery or posterior inferior cerebellar artery might include ischemia to the medulla oblongata via PSA branches, and this anatomy should be kept in mind by interventionalists, radiologists, and neurologists alike.

Muscle Sparing C1-C2 Laminoplasty: Cadaveric Feasibility Study.

BACKGROUND: Posterior cervical approaches for atlantoaxial and craniovertebral junction pathologies with or without instrumentation are often associated with excessive soft tissue dissection and bleeding consequent with disruption of the venous plexus. A few minimally invasive approaches to this region have been reported from clinical and cadaveric studies in an effort to minimize blood loss, reduce soft tissue dissection, and decrease postoperative pain; however, unilateral minimally invasive approaches have not been described. Here, we describe a minimally invasive atlantoaxial and craniovertebral approach. METHODS: Using fresh cadavers, we performed a novel, right-sided, muscle-sparing minimally invasive C1-C2 laminotomy with laminoplasty for access to the atlantoaxial level and craniovertebral junction and used the traditional approach on left sides. RESULTS: Using this approach, the atlantoaxial space and craniovertebral junction with wide and generous exposure via unilateral soft tissue dissection and muscle splitting was achieved. After exposure, the musculoosseous unit was easily repositioned, thus allowing for C1-C2 laminoplasty. Grossly, no damage to the vertebral artery or regional nerves was noted. CONCLUSIONS: We present a novel, unilateral minimally invasive approach to reach the atlantoaxial and craniovertebral junction. This could allow for faster postoperative recovery, less pain and opioid requirement, and increased maintenance of atlantoaxial stability. Such a technique, after being confirmed in patients, could optimize this surgical technique.

Comprehensive review of the mastoid foramen.

Anatomical variations of the mastoid foramen have been observed to vary in a number of qualities including size, number, and location. These variants have the potential to become problematic during surgical approaches to the posterior cranial fossa and mastoid part of the temporal bone, and should thus be appreciated by the surgeon. Herein, we discuss the mastoid foramen in detail including issues with such foramina that should be known to the neurosurgeon.

Anatomic Study Quantifying the Relationship Between the Arcuate Eminence and the Root of the Zygoma: Application to Skull Base Surgery.

OBJECTIVE: The aim of this study was to define the structural relationship between the arcuate eminence (AE) and a known fixed external bony landmark, the root of the zygoma (ZR), and to determine its reliability as a consistent guide for guiding surgical approaches. To our knowledge, this is the only anatomic study to quantify the relationship between the AE and ZR. METHODS: Twenty-one dry temporal bones were measured using digital calipers. The distance from the posterior aspect of the ZR to the midpoint of the AE was measured. Additionally, the anteroposterior distance between the ZR and AE and vertical distance between the 2 structures were measured. Student's t-test was used to compare the left and right sides. RESULTS: An AE was found in every specimen. The mean ZR to AE distance was 30.9 mm. On most sides (91%), the ZR was located more inferiorly than the AE with a mean distance of 3 mm between the 2 structures. The mean distance between the AE and ZR was 17 mm. On all sides, the AE was located posterior to the ZR. No significant differences were found between sides. No anatomic variations or pathologic conditions were noted in any of the specimens. CONCLUSIONS: The ZR is an easily identifiable and consistent bony landmark often used by skull base surgeons. In this investigation, we measured the anatomic relationships between the ZR and AE. Such data might assist in planning surgical trajectories and minimizing complications when skull base pathologies are approached.

The Top 100 Most Cited Journal Articles in Pediatric Neurosurgery.

With the many papers published in the field of pediatric neurosurgery, it is often difficult to recognize those that have the most impact on future papers, i.e., citable papers. However, citation analysis allows one to better understand which papers are impacting the field the most. Therefore, the current study aimed to evaluate this literature. The Journal Citation Report database was searched for publications with the words "pediatric neurosurgery" or "pediatric neuro" in the title. Using the Web of Science Core Collection, the top 100 journal articles in pediatric neurosurgery from the selected journals were identified and citation analysis was used to identify the most impactful articles. A search was performed on Web of Science Core Collection by searching for each journal under "Publication Name" and using the Boolean "OR" function to separate fields. The results were ordered by the "Times Cited" category, which provided a list of all the articles from the eight journals appearing in the most cited order. The timeline used was from 1976 to 2021. The top 100 most cited articles were extracted from this list for analysis. The following variables were collected from each scientific article: publication journal, impact factor of journal, title, number of citations, year and month of publication, and type of article. Eight journals were identified on the basis of our search criteria and the articles were sorted by most cited; 1609 pediatric neurosurgery journal articles were screened to select the 100 most cited since 1976. This compilation could serve to help clinicians and researchers to familiarize themselves with the journal articles included in terms of study type, study field, journal of publication, and recurring authors.

Revisiting the Vertebral Venous Plexus-A Comprehensive Review of the Literature.

The venous drainage of the vertebral and paravertebral regions is important for a better understanding of hematogenous disease spread. Moreover, the spine surgeon must be well acquainted with this anatomy to minimize intraoperative and postoperative complications. A comprehensive review of the vertebral venous plexus (Batson plexus) was performed with a concentration on the clinical and surgical correlations of this venous network.

Chiari 1.5 malformation, accessory odontoid synchondrosis, and ventral compression: case report.

The pathogenesis of Chiari 1 malformations has been explained in several different ways, but extensive evidence suggests a relationship between loss of volume within the posterior cranial fossa and Chiari 1 presentations. It is important to be able to differentiate Chiari 1.5 from Chiari 1 malformations as they have similar clinical presentations, but the latter have progressed further and are characterized by caudal herniations of the brain stem through the foramen magnum. Despite the similarities of presentation, Chiari 1.5 malformations have greater rates of complications following posterior decompression surgeries, which are typically performed to relieve ventral compression. An improved understanding of the odontoid synchondroses could lead to better understanding of Chiari malformations and lead to improved treatment of patients with these presentations. Here we present a rare case of an accessory odontoid synchondrosis in a patient with a Chiari 1.5 malformation and ventral compression.

The proximal humeral attachment of the lateral head of the triceps brachii: a cadaveric study and potential site for radial nerve compression.

BACKGROUND: Knowledge of potential compression sites of peripheral nerves is important to the clinician and surgeon alike. One anatomical location for potential compression of the radial nerve, which is rarely mentioned in the literature, is at the proximal humeral attachment of the lateral head of the triceps brachii at the level of the proximal spiral groove. As no anatomical studies have been devoted to this band, the present study was conducted. METHODS: Ten adult fresh-frozen cadavers were dissected and the lateral head's attachment onto the posterior humerus evaluated for a band. This anatomy and its relation to the radial nerve during range of motion of the elbow and forearm were evaluated. RESULTS: A band was found on 15 of 20 arms. On five sides, the band was comprised of grossly muscle fibers of the lateral head of the triceps brachii and was not tendinous. The bands were crescent-shaped, straight, and duplicated on nine, five, and one arm, respectively. The length of the bands ranged from 1.1 to 2.2 cm (mean 1.54 cm). The width of the bands ranged from 0.5 to 1.1 cm (mean 0.8 cm). With elbow extension and the forearm in neutral, all bands were lax. With elbow extension and the forearm supinated, the bands became tauter less the muscular bands. In elbow extension and with the forearm in supination, the bands became most taut less the muscular bands. CONCLUSIONS: The presence of a fibrous band extending from the lateral head of the triceps brachii is common and should be among the differential diagnoses of anatomical sites for potential proximal radial nerve compression when other more common locations are ruled out.

Duplication of the odontoid process with other congenital defects of the craniocervical Junction: case report and review of the literature.

Duplication of the odontoid process remains a rare developmental pathology that is underrepresented in the current literature. As the pivot point for the craniovertebral junction, the odontoid process is vital for the integrity of the atlanto-axial joint and the ability of the head and cervical spine to rotate correctly. The pathogenesis being incompletely understood, it has been proposed that odontoid process duplication involves faulty sclerotome migration and disruption of the axis ossification center. Patients presenting with this pathology usually have associated structural abnormalities. A detailed anatomical and embryological understanding of the odontoid process is necessary for successful management and treatment of patients presenting with odontoid process duplication. We present a rare case of a patient with a duplicated odontoid process in association with C2-C3 fusion, incomplete anterior arch of C1, variant inferior bony process of the transverse process of C1, and enlarged right jugular foramen.

The inferior intercavernous sinus: An anatomical study with application to trans-sphenoidal approaches to the pituitary gland.

OBJECTIVES: The inferior intercavernous sinus is located below the pituitary gland in the sella turcica. Its presence has been controversial among anatomists because it is not always found on radiological imaging or during cadaveric dissections; however, it is becoming a better-known structure in the neurosurgical and radiological fields, specifically with respect to transsphenoidal surgery. Therefore, the present study was performed to better elucidate this structure at the skull base. PATIENTS AND METHODS: Fifty adult, latex injected cadavers underwent dissection. The presence or absence of the inferior cavernous sinus was evaluated and when present, measurements of its width and length were made. Its connections with other intradural venous sinuses were also documented. RESULTS: An inferior intercavernous sinus was identified in 26 % of specimens. In all specimens, it communicated with the left and right cavernous sinus. The average width and length were 3 mm and 9.5 mm, respectively. In the sagittal plane, the inferior intercavernous sinus was positioned anteriorly in 31 %, at the nadir of the sella turcica in 38 %, and slightly posterior to the nadir of the sella turcica in 31 %. In two specimens (15.4 %), the sinus was plexiform in its shape. In one specimen a diploic vein connected the basilar venous plexus to the inferior intercavernous sinus on its deep surface. CONCLUSION: An improved understanding of the variable anatomy of the inferior intercavernous sinus is important in pathological, surgical, and radiological cases.

Herniation of orbital fat through the inferior orbital fissure and into the infratemporal fossa: a cadaveric case report and review.

Orbital fat herniation is primarily in a subconjunctival location. However, herniation through the inferior orbital fissure (IOF) has been scantly reported. Here, we report a cadaveric case of herniation of orbital fat through the inferior orbital fissure and into the infratemporal fossa. The cadaver's orbital anatomy and orbital fat herniation were found during routine dissection. The details of this case are reported. We also discuss anatomical variations of the inferior orbital fissure as well as the related vascular and nervous system structures related to orbital fat herniation. This is a rare case of a cadaver with this anatomical abnormality.

Caudal Regression Syndrome-A Review Focusing on Genetic Associations.

Caudal regression syndrome (CRS) represents a spectrum of clinical phenotypes with varying degrees of malformation of the lower body with involvement of structures deriving from all 3 layers of the trilaminar embryo. We review areas of active investigation in the diagnosis, etiology, epidemiology, and treatment of the disease with a focus on underlying genetics. CRS pathobiology is complex and multifactorial with a significant contribution from environmental factors as evidenced in twin studies. Contemporary genomic and genetic investigations in both human primary tissue and murine in vitro and in vivo models implicate various genes associated with caudal differentiation and neural cell migration in embryogenesis. A large number of identified targets center around the metabolic regulation of retinoic acid and its derivatives. Dysregulation of retinoic acid homeostasis has been associated with abnormal embryonic cell migration, differentiation, and organogenesis with resulting malformations and agenesis in both a laboratory and a clinical setting. There appears to be a significant overlap in potential genetic targets with CRS and other developmental syndromes with similar presentations, such as VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities) association. CRS represents a spectrum of caudal developmental abnormalities with treatment options limited to mild and moderate expressions of disease. Continued research is necessary to further clarify mechanisms of disease pathobiology and complex polygenetic and environmental interaction. Despite this, progress has been made in identifying genetic targets and downstream effectors contributing to preclinical and clinical progression.

Chordae Willisii Within the Transverse Sinus: Morphologic Study.

OBJECTIVE: Some have suggested that trabeculae within the transverse sinuses (chordae Willisii) might restrict flow and potentially contribute to thrombus organization. In addition, these structures might be encountered with endovascular procedures within the transverse sinus and are now readily seen on imaging. Therefore as anatomic studies of these structures are scant, the current study aimed to better elucidate these structures within the transverse sinus via a morphologic study in cadavers. METHODS: Thirty fresh-frozen, cadaveric transverse sinuses were dissected, and their detailed morphology was recorded. Classification schemes were applied based on the anatomy and orientation of each chordae. RESULTS: Chordae were found on 70% of sides and were statistically more likely to be found on right sides (86.6%) (P < 0.01). Three types and 3 classes of chordae were identified. There was a statistically significant difference between sides regarding type of chordae (P = 0.02). CONCLUSIONS: To date, a comprehensive anatomic evaluation of the intraluminal chordae of the transverse sinuses has been lacking. Knowledge of these bands is also essential to those performing endovascular procedures of the dural venous sinuses and for those interpreting imaging of these structures.