Stereotactic surgery or stereotaxy is a minimally-invasive form of surgical intervention which makes use of a three-dimensional coordinates system to locate small targets inside the body and to perform on them some action such as ablation (removal), biopsy, lesion, injection, stimulation, implantation, radiosurgery etc. "Stereotactic" in Greek (another accepted spelling is "stereotaxic") means movement in space. A minimally invasive medical procedure is defined as one that is carried out by entering the body through the skin or through a body cavity or anatomical opening, but with the smallest damage possible to these structures. ... A cardiothoracic surgeon performs a mitral valve replacement at the Fitzsimons Army Medical Center. ... See Cartesian coordinate system or Coordinates (elementary mathematics) for a more elementary introduction to this topic. ... Ablation is defined as the removal of material from the surface of an object by vaporization, chipping, or other erosive processes. ... A biopsy (in Greek: bios = life and opsy = look/appearance) is a medical test involving the removal of cells or tissues for examination. ... A lesion is a non-specific term referring to abnormal tissue in the body. ... In neurotechnology, deep brain stimulation (DBS) is a surgical treatment involving the implantation of a medical device called a brain pacemaker, which sends electrical impulses to specific parts of the brain. ... Radiosurgery is a medical procedure which allows non-invasive brain surgery, i. ...

In theory, any organ system inside the body can be subjected to stereotactic surgery. Difficulties in setting up a reliable frame of reference (such as bony landmarks which bear a constant spatial relation to soft tissues), however, mean that its applications have been limited to brain surgery. Besides the brain, biopsy and surgery of the breasts have also been attempted. Grays Anatomy illustration of a human femur. ... Insertion of an electrode during neurosurgery for Parkinsons disease. ... A sketch of the human brain by artist Priyan Weerappuli, imposed upon his sketch of the profile of Michaelangelos David In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... okay that is all ...

History

The stereotactic method was first developed by two British scientists in 1908, working at University College London Hospital, Sir Victor Horsley, a physician and neurosurgeon, and Robert H. Clarke, an engineer. The Horsley-Clarke apparatus they developed was used for animal experimentation and implemented a Cartesian (three-orthogonal axis) system. Improved designs of their original device came into use in the 1930s for animal experimentation and are still in wide use today in all animal neuroscience laboratories. 1908 (MCMVIII) was a leap year starting on Wednesday (link will take you to calendar). ... University College London, commonly known as UCL, or simply UC is one of the colleges that makes up the University of London. ... Sir Victor Alexander Haden Horsley (April 14, 1857-July 16, 1916) was an accomplished scientist and professor. ... The Horsley-Clarke apparatus is a device invented in 1908 by British neurosurgeon and scientist Sir Victor A.H. Horsley and his colleague Robert H. Clarke at University College London to allow experimental and surgical intervention in deep-seated structures of the brain in vertebrates. ... This article is in need of attention from an expert on the subject. ... Cartesian means of or relating to the French philosopher and mathematician René Descartes. ... The 1930s (years from 1930–1939) were described as an abrupt shift to more radical and conservative lifestyles, as countries were struggling to find a solution to the Great Depression, also known in Europe as the World Depression. ...

Using the Horsley-Clarke apparatus for human brains was difficult because of the high variability of spatial relations between the skull and the brain. However, by using contrasted brain radiography (particularly pneumoencephalograms and ventriculography) reference points inside the brain could be used, instead of bone landmarks. The first stereotactical devices for humans used the pineal gland as a landmark and the foramen of Monro. Later, other structures, such as the anterior and posterior commissures, became the most commonly used internal cerebral landmarks. It has been suggested that temporal fenestra be merged into this article or section. ... A sketch of the human brain by artist Priyan Weerappuli, imposed upon his sketch of the profile of Michaelangelos David In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... A radiograph of a right elbow-joint Radiography is the use of certain types of electromagnetic radiation—usually ionizing—to view objects. ... The pineal gland (also called the pineal body or epiphysis) is a small endocrine gland in the brain. ... In the brain, the interventricular foramina (or foramina of Monro) are channels that connect the paired lateral ventricles with the third ventricle at the midline of the brain. ... The Anterior Commissure (precommissure) is a bundle of white fibers, connecting the two cerebral hemispheres across the middle line, and placed in front of the columns of the fornix. ... The posterior commissure is a rounded band of white fibers crossing the middle line on the dorsal aspect of the upper end of the cerebral aqueduct. ...

Using this approach between 1947 and 1949, two American neurosurgeons, Ernest A. Spiegel and Henry T. Wycis, and a Swedish neurosurgeon, Lars Leksell, developed the first stereotactic device used for brain surgery in humans. Spiegel and Wycis used the Cartesian coordinate system (also called the translational system) for their device. Leksell's device was of the polar coordinate type (also called spherical), and was far easier to use and calibrate in the operating room. The stereotactic localization system was also used by Leksell in his next invention, a device for radiosurgery of the brain. This system is also used by the Gamma Knife device, and by other neurosurgeons, using linear accelerators, Proton Beam Therapy and Neutron Capture Therapy. Lars Leksell went on to commercialise his inventions by founding Elekta. Year 1947 (MCMXLVII) was a common year starting on Wednesday (the link is to a full 1947 calendar). ... Year 1949 (MCMXLIX) was a common year starting on Saturday (the link is to a full 1949 calendar). ... Lars Leksell (1907-1986) was a Swedish physician and Professor of Neurosurgery at the Karolinska Institute in Stockholm, Sweden. ... This article describes some of the common coordinate systems that appear in elementary mathematics. ... Calibration is the determination, by measurement or comparison with a standard, of the correct value of each reading on a measuring instrument. ... Radiosurgery is a medical procedure which allows non-invasive brain surgery, i. ... In medicine, Leksell Gamma Knife is a neurosurgical device used to treat brain tumors. ... A Linear particle accelerator is an electrical device for the acceleration of subatomic particles. ... Proton therapy is a kind of external beam radiotherapy where protons are directed to a tumor site. ... Lars Leksell (1907-1986) was a Swedish physician and Professor of Neurosurgery at the Karolinska Institute in Stockholm, Sweden. ... Elekta, is a Swedish medical systems company founded by Lars Leksell, supplying neurosurgery, radiosurgery, radiotherapy, and magneto-encephalography equipment. ...

In 1976, a system was developed to use computer assisted imaging to help make the location of the target more precise. It was developed jointly by the University of Toronto and Toronto General Hospital. The system used a pre-scanned image of the brain loaded into a Tektronix graphics terminal in the operating room. Low level voltages were applied to the brain and the co-ordinates and patient response entered by keyboard, the image on the screen showed the brain overlaid by graphics images (such as a hand) indicating the type of response [1] [2] The University of Toronto (U of T) is a coeducational public research university in Toronto, Ontario. ... The R.R. McEwen atrium of the Toronto General Hospital, southwest corner of the site, view from University Avenue. ... Tektronix is a United States corporation that is currently a major presence in the test, measurement, and measuring industry. ...

The method continued to evolve, and presently uses a complex mixture of image-guided surgery using intraroom computed tomography, magnetic resonance imaging and stereotactic localization. Image-guided surgery is the general term used for any surgical procedure where the surgeon uses indirect visualization to operate, i. ... This article does not cite its references or sources. ... For the scientific journal entitled Magnetic Resonance Imaging, see Magnetic Resonance Imaging (journal). ...

How it works

Stereotactic surgery works on the basis of three main components:

• A stereotactic atlas of the targeted anatomical structures
• A stereotactic device or apparatus
• A stereotactic localization and placement procedure

The stereotactic atlas is a series of cross sections of anatomical structure (for example, a human brain), depicted in reference to a two-coordinate frame. Thus, each brain structure can be easily assigned a range of three coordinate numbers, which will be used for positioning the stereotactic device. In most atlases, the three dimensions are: latero-lateral (x), dorso-ventral (y) and rostro-caudal (z). For other uses, see Atlas (disambiguation). ...

The stereotactic apparatus uses a set of three coordinates (x, y and z) in an orthogonal frame of reference (cartesian coordinates), or, alternatively, a polar coordinates system, also with three coordinates: angle, depth and antero-posterior location. The mechanical device has head-holding clamps and bars which puts the head in a fixed position in reference to the coordinate system (the so-called zero or origin). In small laboratory animals, these are usually bone landmarks which are known to bear a constant spatial relation to soft tissue. For example, brain atlases often use the external auditory meatus, the inferior orbital ridges, the median point of the maxilla between the incisive teeth. or the bregma (confluence of sutures of frontal and parietal bones), as such landmarks. In humans, the reference points, as described above, are intracerebral structures which are clearly discernible in a radiograph of tomogram. Cartesian means relating to the French mathematician and philosopher Descartes, who, among other things, worked to merge algebra and Euclidean geometry. ... This article describes some of the common coordinate systems that appear in elementary mathematics. ... Grays Anatomy illustration of a human femur. ... Bat ears come in different sizes and shapes The ear is the sense organ that detects sound. ... A human eye. ... The maxillae are the largest bones of the face, except for the mandible, and form, by their union, the whole of the upper jaw. ... The parietal bones are bones in the human skull and form, by their union, the sides and roof of the cranium. ...

Guide bars in the x, y and z directions (or alternatively, in the polar coordinate holder), fitted with high precision Vernier scales allow the neurosurgeon to position the point of a probe (an electrode, a cannula, etc.) inside the brain, at the calculated coordinates for the desired structure, through a small trephined hole in the skull. A vernier scale lets one read more precisely from a measurement scale. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... A cannula (pl. ...

Presently, there are a number of manufacturers of stereotactic devices fitted for neurosurgery in humans, as well as for animal experimentation.

See also

• Neurosurgery
• Radiosurgery
• Psychosurgery
• Neuroscience
• Horsley-Clarke apparatus
• Gamma knife

Insertion of an electrode during neurosurgery for Parkinsons disease. ... Radiosurgery is a medical procedure which allows non-invasive brain surgery, i. ... Psychosurgery is a term for surgeries of the brain involving procedures that modulate the performance of the brain, and thus effect changes in cognition, with the intent to treat or alleviate severe mental illness. ... Drawing of the cells in the chicken cerebellum by S. Ramón y Cajal Neuroscience is a field that is devoted to the scientific study of the nervous system. ... The Horsley-Clarke apparatus is a device invented in 1908 by British neurosurgeon and scientist Sir Victor A.H. Horsley and his colleague Robert H. Clarke at University College London to allow experimental and surgical intervention in deep-seated structures of the brain in vertebrates. ... In medicine, Leksell Gamma Knife is a neurosurgical device used to treat brain tumors. ...

External links and references

• Robert Levy, A Short History of Stereotactic Surgery, Cyber Museum of Neurosurgery. This is based on
  • Patrick J. Kelly, "Introduction and Historical Aspects", Tumor Stereotaxis, Philadelphia: W.B. Saunders Company (1991)
  • Philip L. Gildenberg, "Stereotactic Surgery: Present and Past", Stereotactic Neurosurgery, (Editor: M. Peter Heilbrun) Baltimore: Williams and Wilkins (1988)
• Sabbatini, RME: Stereotactic Neurosurgery. In: The History of Psychosurgery. Brain & Mind Magazine, 2, 1997.
• Organization of the human thalamus.
• graphic display of results of subcortical stimulation during stereotactic surgery