Stereotactic surgery - AbsoluteAstronomy.com

Stereotactic surgery or stereotaxy (not to be confused with the virtuality concept of stereotaxy
Stereotaxy
Stereotaxy from stereo meaning solidity, and tactile meaning touch) refers to any technique that involves the recording and reproduction of three-dimensional haptic information or creating an illusion of depth to the sense of touch within an otherwise-flat surface...

) is a minimally invasive form of surgical

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a 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

Ablation

Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...

, biopsy

Biopsy

A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...

, lesion

Lesion

A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...

, injection, stimulation

Deep brain stimulation

Deep brain stimulation 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...

, implantation, radiosurgery

Radiosurgery

Radiosurgery is a medical procedure that allows non-invasive treatment of benign and malignant tumors. It is also known as stereotactic radiotherapy, when used to target lesions in the brain, and stereotactic body radiotherapy when used to target lesions in the body...

(SRS) etc. "Stereotactic" in Greek (another accepted spelling is "stereotaxic")

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 bone

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

landmarks which bear a constant spatial relation to soft tissues), however, mean that its applications have been limited to brain surgery

Neurosurgery

Neurosurgery is the medical specialty concerned with the prevention, diagnosis, treatment, and rehabilitation of disorders which affect any portion of the nervous system including the brain, spine, spinal cord, peripheral nerves, and extra-cranial cerebrovascular system.-In the United States:In...

. Besides the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

, biopsy and surgery of the breast

Breast

The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

are done routinely to locate, sample (biopsy) and remove tissue. Plain X-ray images (radiographic

Radiography

Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....

mammography), computed tomography

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

, and magnetic resonance imaging

Magnetic resonance imaging

Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...

can be used to guide the procedure.

History

The stereotactic method was first developed by two British scientists in 1908, working at University College London

University College London

University College London is a public research university located in London, United Kingdom and the oldest and largest constituent college of the federal University of London...

Hospital, Sir Victor Horsley

Victor Horsley

Sir Victor Alexander Haden Horsley was an accomplished scientist and professor. He was born in Kensington, London. He was educated at Cranbrook School, Kent and studied medicine at University College London and in Berlin, Germany , and in the same year started his career as a house surgeon and...

, a physician and neurosurgeon, and Robert H. Clarke, a physiologist. The Horsley–Clarke apparatus they developed was used for animal experimentation and implemented a Cartesian

Cartesian coordinate system

A Cartesian coordinate system specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances from the point to two fixed perpendicular directed lines, measured in the same unit of length...

(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

Neuroscience

Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...

laboratories.

Using the Horsley–Clarke apparatus for human brains was difficult because of the inability to visualize intracranial anatomic detail via radiography

Radiography

. However, contrasted brain radiography (particularly pneumoencephalography and ventriculography

Cerebral ventriculography

Cerebral ventriculography is a medical procedure developed by Walter Dandy, and designed to enable visualization of structures inside the skull. In this procedure, holes are drilled in the skull, and air pumped through the holes in to the ventricles, to facilitate clearer imaging on X-rays.It has...

) permitted the visualization of intracranial anatomic reference points or landmarks. The first stereotactic devices for humans used the pineal gland

Pineal gland

The pineal gland is a small endocrine gland in the vertebrate brain. It produces the serotonin derivative melatonin, a hormone that affects the modulation of wake/sleep patterns and seasonal functions...

and the foramen of Monro as landmarks. Later, other anatomic reference points such as the anterior

Anterior commissure

The anterior commissure is a bundle of nerve fibers , connecting the two cerebral hemispheres across the midline, and placed in front of the columns of the fornix...

and posterior commissure

Posterior commissure

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. It is important in the bilateral pupillary light reflex....

s were used as intracranial landmarks. These landmarks were used with a brain atlas to estimate the location of intracranial anatomic structures that were not visible in radiographs.

Using this approach between 1947 and 1949, two American neurosurgeons, Ernest A. Spiegel and Henry T. Wycis, and a Swedish neurosurgeon, Lars Leksell

Lars Leksell

Lars Leksell was a Swedish physician and Professor of Neurosurgery at the Karolinska Institute in Stockholm, Sweden. He was the inventor of radiosurgery.-Life and work:...

, developed the first stereotactic devices that were 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 used the polar coordinate system (also called spherical) that 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

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 commercialize his inventions by founding Elekta

Elekta

Elekta is a swedish company that provides radiation therapy, radiosurgery, related equipment and clinical management for the treatment of cancer and brain disorders.-History:...

.

In 1978, Russell A. Brown

Russell A. Brown

Russell A. Brown is an American physician and computer scientist. He is the inventor of a method for directing stereotactic surgery using computed tomography....

, an American physician and computer scientist, invented a simple technique to guide stereotactic surgery using computed tomography

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

.
This technique significantly improves surgical precision because computed tomography permits direct visualization of intracranial anatomic detail. The technique uses fiducial

Fiduciary marker

A fiducial marker or fiducial is an object used in the field of view of an imaging system which appears in the image produced, for use as a point of reference or a measure...

s to create extracranial landmarks in each tomographic image or section. These landmarks specify the spatial orientation of that section with respect to the stereotactic device. Brown's invention stimulated intense interest in stereotaxy and radiosurgery

Radiosurgery

. It is widely used today in the Brown-Roberts-Wells (BRW) stereotactic system as well as other stereotactic and radiosurgical devices.

The stereotactic method has continued to evolve, and at present uses an elaborate mixture of image-guided surgery

Image-guided surgery

Image-guided surgery is the general term used for any surgical procedure where the surgeon employs tracked surgical instruments in conjunction with preoperative or intraoperative images in order to indirectly guide the procedure. Most image-guided surgical procedures are minimally invasive...

using computed tomography

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

, magnetic resonance imaging

Magnetic resonance imaging

Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...

and stereotactic localization.

How it works

Stereotactic surgery works on the basis of three main components:

A stereotactic planning system, including atlas
Atlas
An atlas is a collection of maps; it is typically a map of Earth or a region of Earth, but there are atlases of the other planets in the Solar System. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats...

, multimodality image matching tools, coordinates calculator, etc.
A stereotactic device or apparatus
A stereotactic localization and placement procedure

Modern stereotactic planning system are computer based. 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).

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

Bone

landmarks which are known to bear a constant spatial relation to soft tissue. For example, brain atlases often use the external auditory meatus

Ear

The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....

, the inferior orbital

Human eye

The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...

ridges, the median point of the maxilla

Maxilla

The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

between the incisive teeth

Incisor

Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...

. or the bregma

Bregma

The bregma is the anatomical point on the skull at which the coronal suture is intersected perpendicularly by the sagittal suture.-Location:The bregma is located at the intersection of the coronal suture and the sagittal suture on the superior middle portion of the calvarium...

(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

Radiography

or tomogram.

Guide bars in the x, y and z directions (or alternatively, in the polar coordinate holder), fitted with high precision vernier scale

Vernier scale

A vernier scale is an additional scale which allows a distance or angle measurement to be read more precisely than directly reading a uniformly-divided straight or circular measurement scale...

s allow the neurosurgeon to position the point of a probe (an electrode

Electrode

An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...

, a cannula

Cannula

A cannula or canula is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of data...

, etc.) inside the brain, at the calculated coordinates for the desired structure, through a small trephined hole in the skull.

Currently, a number of manufacturers produce stereotactic devices fitted for neurosurgery

Neurosurgery

in humans, as well as for animal experimentation.

Types of Stereotactic Frame Systems

Simple Orthogonal System: The probe is directed perpendicular to a square base unit fixed to the skull. These provides three degrees of freedom by means of a carriage that moved orthogonally along the base plate or along a bar attached parallel to the base plate of the instrument. Attached to the carriage was a second track that extended across the head frame perpendicularly.
Burr Hole Mounted System: This provides a limited range of possible intracranial target points with a fixed entry point. They provided two angular degrees of freedom and a depth adjustment. The surgeon could place the burr hole over nonessential brain tissue and utilize the instrument to direct the probe to the target point from the fixed entry point at the burr hole.
Arc-Quadrant Systems: Probes are directed perpendicular to the tangent of an arc (which rotates about the vertical axis) and a quadrant (which rotates about the horizontal axis). The probe, directed to a depth equal to the radius of the sphere defined by the arc-quadrant, will always arrive at the center or focal point of that sphere.
Arc-Phantom Systems: An aiming bow attaches to the head ring, which is fixed to the patient's skull, and can be transferred to a similar ring that contains a simulated target. In this system, the phantom target is moved on the simulator to 3D coordinates. After adjusting the probe holder on the aiming bow so that the probe touches the desired target on the phantom, the transferable aiming bow is moved from the phantom base ring to the base ring on the patient. The probe is then lowered to the determined depth in order to reach the target point deep in the patient's brain.

Stereotactic Surgery Research in Rodents

Stereotactic surgery can be used to aid research in several different types of animal studies. Specifically, it is used to target specific sites of the brain and directly introduce pharmacological agents to the brain which otherwise may not be able to cross the blood-brain barrier

Blood-brain barrier

The blood–brain barrier is a separation of circulating blood and the brain extracellular fluid in the central nervous system . It occurs along all capillaries and consists of tight junctions around the capillaries that do not exist in normal circulation. Endothelial cells restrict the diffusion...

. In rodents, the main applications of stereotactic surgery are to introduce fluids directly to the brain or to implant cannula

Cannula

A cannula or canula is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of data...

and microdialysis

Microdialysis

- The microdialysis technique:Microdialysis is a semi-invasive sampling technique that is used for continuous measurement of free, unbound analyte concentrations in the extracellular fluid of virtually any tissue. Analytes may include endogenous molecules to assess their biochemical functions in...

probes. Site specific central microinjections are used when rodents do not need to be awake and behaving or when the substance to be injected has a long duration of action. For protocols in which rodents’ behaviors must be assessed soon after injection, stereotactic surgery can be used to implant a cannula through which the animal can be injected after recovery from the surgery. These protocols take longer than site-specific central injections in anesthetized mice because they require the construction of cannulae, wire plugs, and injection needles, but induce less stress in the animals because they allow for a recovery period for the healing of trauma induced to the brain before injection. Surgery can also be used for microdialysis protocols to implant and tether the dialysis probe and guide cannula.

Stereotactic radiosurgery (SRS) in Cancer treatment

Stereotactic radiosurgery can successfully treat many different types of tumors, both benign and malignant. The malignant brain tumors treated most often are the "brain metastasis" or tumors that have spread to the brain. A study in 2008 by The University of Texas M. D. Anderson Cancer Center indicated that stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) for treatment of metastatic brain tumours have more than twice the risk of developing learning and memory problems than those treated with SRS alone. “While both approaches are in practice and both are equally acceptable, data from this study suggest that oncologists should offer SRS alone as the upfront, initial therapy for patients with up to three brain metastases,” Three of the latest radiosurgery treatments, are CyberKnife

Cyberknife

The CyberKnife is a frameless robotic radiosurgery system used for treating benign tumors, malignant tumors and other medical conditions. The system was invented by John R. Adler, a Stanford University Professor of Neurosurgery and Radiation Oncology, and Peter and Russell Schonberg of Schonberg...

, Gamma Knife and the Stereotactic Linear Accelerator with Image Guided Radiotherapy, Respiratory Gating, Cone beam CT, Kv Imaging and RapidArc. Failure to properly focus the powerful radiation beam produced by the linear accelerator or inadequate shielding can result in crippling injuries.

Stereotactic body radiosurgery has also been used to treat cancer by delivering high doses of radiation accurately to tumors within the body. Prior to the recent development of stereotactic body radiosurgery, the best alternative was standard external beam radiotherapy. Yet, the problem with standard external beam radiotherapy is that much is exposed to high doses of radiation, placing patients at risk for radiation damage.

The team at Methodist Hospital under Dr. Robert T. Woodburn have had special training and substantial experience in the field of stereotactic radiosurgery. According to their work done, SBR cancer treatment is not surgery at all. It is an outpatient procedure that requires three visits to the radiation oncology department which utilizes multiple tightly conformed radiation beams converging at the tumor. The low volume exposed to radiation allows very high doses to be given to the tumor leading to cure rates comparable to surgery. Thus, the low volume of exposure SBR has a low risk of long term complications in the treatment of cancer. Although this treatment is given to patients unable or unwilling to undergo surgery for various reasons, surgery remains the gold standard.

Stereotactic Surgery and Parkinson's Disease

Functional neurosurgery comprises treatment of several disorders such as Parkinson’s disease, hyperkinesis

Hyperkinesis

Hyperkinesia, also known as hyperkinesis, refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both...

, disorder of muscle tone, intractable pain, convulsive disorders and psychological phenomena. Treatment for these phenomena was believed to be located in the superficial parts of the CNS and PNS. Most of the interventions made for treatment consisted of cortical extirpation.
To alleviate extra pyramidal disorders, pioneer Russell Mayer dissected or transected the head of the caudate nucleus

Caudate nucleus

The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system.-Anatomy:...

and part of the putamen

Putamen

The putamen is a round structure located at the base of the forebrain . The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that comprises the basal ganglia. Through various pathways, the putamen is connected to the substantia nigra and globus pallidus...

and globus pallidus

Globus pallidus

The globus pallidus also known as paleostriatum, is a sub-cortical structure of the brain. Topographically, it is part of the telencephalon, but retains close functional ties with the subthalamus - both of which are part of the extrapyramidal motor system...

. Attempts to abolish intractable pain were made with success by transaction of the spinothalamic tract

Spinothalamic tract

The spinothalamic tract is a sensory pathway originating in the spinal cord. It transmits information to the thalamus about pain, temperature, itch and crude touch...

at spinal modullary level and further proximally, even at meencephalic levels.

In 1993-1941 Putman and Oliver tried to improve Parkinsonism and hyperkinesias by trying a series of modifications of the lateral and antero-lateral cordotomy. Additionally, other scientists like Schurman, Walker, and Guiot made significant contributions to functional neurosurgery. In 1953, Cooper discovered by chance that ligation of the anterior chorioidal artery resulted in improvement of Parkinson's disease. Similarly, when Grood was performing an operation in a patient with Parkinson’s, he accidentally lesioned the thalamus

Thalamus

The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

. This caused the patient’s tremors to stop. From then on, thalamic lesions became the target point with more satisfactory results.

More recent clinical applications can be seen at the University of Virginia School of Medicine, where Deep Brain Stimulation

Deep brain stimulation

Deep brain stimulation 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...

(DBS), Pallidotomy

Pallidotomy

Pallidotomy is a procedure where a tiny electrical probe is placed in the globus pallidus , which is then heated to 80 degrees celsius for 60 seconds, to destroy a small area of brain cells...

and Thalamotomy

Thalamotomy

First introduced in the 1950s, thalamotomy is an invasive procedure, primarily effective for tremors such as those associated with Parkinson's Disease , where a selected portion of the thalamus is surgically destroyed...

are surgeries used to treat Parkinson’s disease. During DBS, an electrode is placed into the thalamus, the pallidum of the subthalmamic nucleus, parts of brain that are involved in motor control, and are affected by Parkinson’s Disease. The electrode is connected to a small battery operated stimulator that is placed under the collarbone, where a wire runs beneath the skin to connect it to the electrode in the brain. The stimulator produces electrical impulses that affect the nerve cells around the electrode and should help alleviate tremors or symptoms that are associated with the affected area.

In Thalamotomy

Thalamotomy

, a needle electrode is placed into the thalamus, and the patient must cooperate with tasks assigned to find the affected area- after this are of the thalamus is located, a small high frequency current is applied to the electrode and this destroys a small part of the thalamus. Approximately 90% of patients experience instantaneous tremor relief.

In Pallidotomy

Pallidotomy

Pallidotomy is a procedure where a tiny electrical probe is placed in the globus pallidus , which is then heated to 80 degrees celsius for 60 seconds, to destroy a small area of brain cells...

, an almost identical procedure to thalamotomy, a small part of the palladium is destroyed and 80% of patients see improvement in rigidity and hypokinesiia and a tremor relief or improvement comes weeks after the procedure.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

History

How it works

Types of Stereotactic Frame Systems

Stereotactic Surgery Research in Rodents

Stereotactic radiosurgery (SRS) in Cancer treatment

Stereotactic Surgery and Parkinson's Disease

See also

External links