The cerebrospinal venous system (CSVS) consists of the interconnected venous systems of the brain (the
cerebral venous system) and the spine (the
vertebral venous system).
Introduction
The anatomic connections between the cerebral and vertebral venous systems was accurately depicted in 1819 by
Gilbert Breschet
Gilbert Breschet (7 July 1784 – 10 May 1845) was a French anatomist born in Clermont-Ferrand.
He studied medicine at the University of Paris, and in 1812 was conferred as doctor of medicine in Paris. In 1836 he succeeded Jean Cruveilhier ...
, a French physician later to become Professor of Anatomy at Faculté de médecine de Paris. However, the significance and physiology of this venous complex remained obscure for more than a century, until the seminal work of Oscar Batson. Batson, a Professor of Anatomy at the University of Pennsylvania, in 1940 detailed the anatomy and physiology of the cerebrospinal venous system and its role in the spread of metastases.
[Batson, O.V., The Function of the Vertebral Veins and their role in the spread of metastases. Annals of Surgery, 1940. 112: p. 138-149] Batson’s work remains primarily known for its accurate depiction of the vertebral venous system as the route of
metastasis
Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...
of cancer from the prostate to the spine, and the vertebral venous system is often referred to as
Batson venous plexus
The Batson venous plexus (Batson veins) is a network of valveless veins in the human body that connect the deep pelvic veins and thoracic veins (draining the inferior end of the urinary bladder, breast and prostate) to the internal vertebral veno ...
or Batson’s plexus. It is less commonly recognized that Batson’s detailed experiments also demonstrated the direct anatomic connection between the vertebral and cerebral venous system, an anatomical and physiological fact that was later confirmed by others.
[Epstein, H.M., et al., The vertebral venous plexus as a major cerebral venous outflow tract. Anesthesiology, 1970. 32(4): p. 332-7][Zouaoui, A. and G. Hidden, The cervical vertebral venous plexus, a drainage route for the brain. Surg Radiol Anat, 1989. 11(1): p. 79-80][San Millan Ruiz, D., et al., The craniocervical venous system in relation to cerebral venous drainage. AJNR Am J Neuroradiol, 2002. 23(9): p. 1500-8] It was later recognized that the cerebrospinal venous system represents a main route for efflux of venous blood from the brain.
Modern imaging methodology, including
MR scanning
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio w ...
, have detailed the
anastomoses
An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be norm ...
of the cerebral and spinal venous systems in the
suboccipital region.
[Arnautovic, K.I., et al., The suboccipital cavernous sinus. J Neurosurg, 1997. 86(2): p. 252-62] Batson, and others had recognized that blood flow in the cerebrospinal venous system was bi-directional, a unique feature that was enabled by a general lack of venous valves in these venous plexuses.
[Batson, O.V., The vertebral vein system. Caldwell lecture, 1956. Am J Roentgenol Radium Ther Nucl Med, 1957. 78(2): p. 195-212] This bi-directional flow was thought to have physiologic significance with regard to the maintenance of pressure
hemostasis
In biology, hemostasis or haemostasis is a process to prevent and stop bleeding, meaning to keep blood within a damaged blood vessel (the opposite of hemostasis is hemorrhage). It is the first stage of wound healing. This involves coagulation, wh ...
within the cranium with changes in posture. The terms “cerebrospinal venous system” and “CSVS” were coined in a 2006 review that has itself been cited in a number of subsequent articles and reviews.
[De Wyngaert, R., I. Casteels, and P. Demaerel, Orbital and anterior visual pathway infection and inflammation. Neuroradiology, 2009. 51(6): p. 385-96][Nathoo, N., et al., History of the vertebral venous plexus and the significant contributions of Breschet and Batson. Neurosurgery, 2011. 69(5): p. 1007-14]
Continuity of the brain and spine venous systems
Beginning in 1937 Batson began a series of injection experiments investigating the anatomy and physiology of the cerebrospinal venous system.
His carefully documented results demonstrated the continuity of the venous systems of the brain and the spine, as injections of
contrast dyes into venous systems feeding into the spinal venous plexus led to the appearance of contrast material in the cerebral veins (Figures 5 and 7, Batson 1940).
Batson noted "the extensive filling of the vertebral veins, the superior longitudinal sinus, transverse sinus as well as other dural and cerebral veins" following injection of radiopaque material into a superficial venule in the left breast (Batson 1940, Figure 5, page 143). Subsequent studies by multiple independent authors replicated Batson's findings of the continuity of the cerebral and vertebral venous systems, and the important physiological consequences of this continuity. For example, in 1996, Arnautovic et al., summarizing the results of their own work and that of others, stated: "In addition to confirming that the vertebral venous plexus is a direct continuation of the cranial venous sinuses, our study showed that it is also indirectly connected to these sinuses via the suboccipital cavernous sinus. The vertebral venous plexus is involved in regulating
intracranial
The cranial cavity, also known as intracranial space, is the space within the skull that accommodates the brain. The skull minus the mandible is called the ''cranium''. The cavity is formed by eight cranial bones known as the neurocranium that in ...
pressure, transmitting the influence of the respiratory and cardiac pressures to the intracranial compartment and equalizing the pressures within the venous system.
". The continuity of the cerebral and vertebral venous systems was therefore essential to an understanding of both normal physiology, as well as to an understanding of the distribution of tumor metastases, as Batson had so elegantly demonstrated.
A route for metastases and infection
It is now recognized that the cerebrospinal venous system represents not only a route for dissemination of metastases, but also a route for dissemination of infection throughout the cerebrospinal axis, in both directions.
Batson's legacy
In 1957 Batson wrote, ""It seems incredible that a great functional complex of veins would escape recognition as a system until 1940 .... In the first four decades of the last
9th
9 (nine) is the natural number following and preceding .
Evolution of the Arabic digit
In the beginning, various Indians wrote a digit 9 similar in shape to the modern closing question mark without the bottom dot. The Kshatrapa, Andhra and ...
century, our knowledge of the vertebral veins was developed and then almost forgotten.
". During the past half century, our appreciation of Batson's findings and concepts has grown, expanding beyond his explanation for previously inexplicable routes of tumor metastasis. In 2011, researchers from the Department of Neurological Surgery at Ohio State Medical Center summarized the significance and current understanding of several aspects of the CSVS in their review article: "Today, the vertebral venous plexus is considered part of the cerebrospinal venous system, which is regarded as a unique, large-capacitance, valveless plexiform venous network in which flow is bidirectional that plays an important role in the regulation of intracranial pressure with changes in posture and in venous outflow from the brain, whereas in disease states, it provides a potential route for the spread of tumor, infection, or emboli.".
Therapeutic use
The cerebrospinal venous system may serve as a route for therapeutic delivery of large molecules to the brain and spinal cord, as discussed: "... the drug enters the brain through the cerebrospinal venous system..."(
Sun Sentinel
The ''Sun Sentinel'' (also known as the ''South Florida Sun Sentinel'', known until 2008 as the ''Sun-Sentinel'', and stylized on its masthead as ''SunSentinel'') is the main daily newspaper of Fort Lauderdale, Florida, as well as surrounding Br ...
, December 9, 2012, page 21A).
[Brochu, N., ''Stroke Patients Get a New Shot at Hope'', Sun Sentinel, December 9, 2012, front page, Fort Lauderdale, Florida]
See also
Glymphatic system
References
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Cerebrospinal venous system