Ablative brain surgery
Encyclopedia
Ablative brain surgery (also known as brain lesioning) is the surgical
ablation
by burning or freezing of brain
tissue to treat neurological
or psychological disorders. The lesion
s it causes are irreversible.
Ablative brain surgery was first introduced by Pierre Flourens (1774-1867), a French physiologist. He removed different parts of the nervous system on animals and observed what effects were caused by the removal of certain parts. For example, if an animal could not move its arm after a certain part was removed, it was assumed that the region would control arm movements. The method of removal of part of the brain was termed "experimental ablation". With the use of experimental ablation, Flourens claimed to find the area of the brain that controlled heart rate and breathing.
Ablative brain surgery is also often used as an research tool in neurobiology. For example, by ablating specific brain regions and observing differences in animals subjected to behavioral tests, the functions of the removed areas may be inferred.
Experimental ablation is used in research on animals. Such research is considered unethical on humans, but the effects of brain lesions (caused by accidents or diseases) on behavior can be observed to draw conclusions on the functions of different parts of the brain.
. In the 1990s, the pallidum was a common surgical target. Unilateral pallidotomy improves tremor
and dyskinesia
on one side of the body (opposite the side of the brain surgery), but bilateral pallidotomy was found to cause irreversible deterioration in speech and cognition
. The thalamus
is another potential target for treating tremor; in some countries, so is the subthalamic nucleus
, although not in the United States
due to its severe side effects. Generally, deep brain stimulation
surgery (DBS) is considered preferable to ablation because it has the same effect and is adjustable and reversible. However, for patients for whom DBS is not feasible, ablation of the subthalamic nucleus has been shown to be safe and effective. DBS is not suitable for certain patients. Instances in which the patient suffers from immunodeficiency or obtains any infections due to the insertion of the neurostimulatory device are examples of situations in which DBS is not the favoured or chosen procedure. However, a major aspect contributing to the drawbacks of DBS is simply its cost. Due to this, DBS cannot be carried out in less prosperous regions of the world. In such situations, the creation of a lasting lesion in the subthalamic nucleus (STN) is the favoured surgical procedure. In situations where the patient happens to be young and the surgical procedure is going to be done on the non-dominant side of the brain, a lesion might be favored to evade numerous pacemaker replacements. More so, patients who gain relief from stimulation devoid of any side effects and need a pacemaker change may have a lesion performed on them in the same position. The stimulation parameters act as a guide for the preferred size of the lesion. In order to identify the part of the brain that is to be destroyed, new techniques such as micro electrode mapping have been developed .
s have been treated by ablation of the trigeminal nerve
, but have not been very effective. Other surgical treatments for cluster headaches are under investigation.
that carry out ablative psychosurgical procedures. Belgium, the United Kingdom, and Venezuela are other examples of countries where the technique is still used.
In the People's Republic of China
, surgical ablation was used to treat psychological and neurological disorders, particularly schizophrenia
, but also including clinical depression
, obsessive-compulsive disorder
, and epilepsy
. The official Xinhua News Agency
has since reported that China's Ministry of Health has banned the procedure for schizophrenia and severely restricted the practice for other conditions.
s have been shown to be effective in ablation of both cerebral and cerebellar
tissue. A laser called Er:YAG, for example, allows great precision in location and size of the lesion and causes little to no thermal damage to adjacent tissue.
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...
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:...
by burning or freezing of 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,...
tissue to treat neurological
Neurological disorder
A neurological disorder is a disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or in the nerves leading to or from them, can result in symptoms such as paralysis, muscle weakness, poor coordination, loss of sensation, seizures,...
or psychological disorders. The 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 :...
s it causes are irreversible.
Ablative brain surgery was first introduced by Pierre Flourens (1774-1867), a French physiologist. He removed different parts of the nervous system on animals and observed what effects were caused by the removal of certain parts. For example, if an animal could not move its arm after a certain part was removed, it was assumed that the region would control arm movements. The method of removal of part of the brain was termed "experimental ablation". With the use of experimental ablation, Flourens claimed to find the area of the brain that controlled heart rate and breathing.
Ablative brain surgery is also often used as an research tool in neurobiology. For example, by ablating specific brain regions and observing differences in animals subjected to behavioral tests, the functions of the removed areas may be inferred.
Experimental ablation is used in research on animals. Such research is considered unethical on humans, but the effects of brain lesions (caused by accidents or diseases) on behavior can be observed to draw conclusions on the functions of different parts of the brain.
Parkinson's disease
Surgical ablation has been used to treat Parkinson's diseaseParkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
. In the 1990s, the pallidum was a common surgical target. Unilateral pallidotomy improves tremor
Tremor
A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the...
and dyskinesia
Dyskinesia
Dyskinesia is a movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements, similar to tics or choreia. Dyskinesia can be anything from a slight tremor of the hands to uncontrollable movement of, most commonly, the upper body but...
on one side of the body (opposite the side of the brain surgery), but bilateral pallidotomy was found to cause irreversible deterioration in speech and cognition
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...
. 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...
is another potential target for treating tremor; in some countries, so is the subthalamic nucleus
Subthalamic nucleus
The subthalamic nucleus is a small lens-shaped nucleus in the brain where it is, from a functional point of view, part of the basal ganglia system. Anatomically, it is the major part of subthalamus. As suggested by its name, the subthalamic nucleus is located ventral to the thalamus. It is also...
, although not in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
due to its severe side effects. Generally, 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...
surgery (DBS) is considered preferable to ablation because it has the same effect and is adjustable and reversible. However, for patients for whom DBS is not feasible, ablation of the subthalamic nucleus has been shown to be safe and effective. DBS is not suitable for certain patients. Instances in which the patient suffers from immunodeficiency or obtains any infections due to the insertion of the neurostimulatory device are examples of situations in which DBS is not the favoured or chosen procedure. However, a major aspect contributing to the drawbacks of DBS is simply its cost. Due to this, DBS cannot be carried out in less prosperous regions of the world. In such situations, the creation of a lasting lesion in the subthalamic nucleus (STN) is the favoured surgical procedure. In situations where the patient happens to be young and the surgical procedure is going to be done on the non-dominant side of the brain, a lesion might be favored to evade numerous pacemaker replacements. More so, patients who gain relief from stimulation devoid of any side effects and need a pacemaker change may have a lesion performed on them in the same position. The stimulation parameters act as a guide for the preferred size of the lesion. In order to identify the part of the brain that is to be destroyed, new techniques such as micro electrode mapping have been developed .
Cluster headaches
Cluster headacheCluster headache
Cluster headache, nicknamed "suicide headache", is a neurological disease that involves, as its most prominent feature, an immense degree of pain in the head. Cluster headaches occur periodically: spontaneous remissions interrupt active periods of pain. The cause of the disease is currently unknown...
s have been treated by ablation of the trigeminal nerve
Trigeminal nerve
The trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
, but have not been very effective. Other surgical treatments for cluster headaches are under investigation.
Psychiatric disorders
Ablative psychosurgery continues to be used in a few centres in various countries. In the US there are a few centres including Massachusetts General HospitalMassachusetts General Hospital
Massachusetts General Hospital is a teaching hospital and biomedical research facility in the West End neighborhood of Boston, Massachusetts...
that carry out ablative psychosurgical procedures. Belgium, the United Kingdom, and Venezuela are other examples of countries where the technique is still used.
In the People's Republic of China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
, surgical ablation was used to treat psychological and neurological disorders, particularly schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
, but also including clinical depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
, obsessive-compulsive disorder
Obsessive-compulsive disorder
Obsessive–compulsive disorder is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing the associated anxiety, or by a combination of such obsessions and compulsions...
, and epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
. The official Xinhua News Agency
Xinhua News Agency
The Xinhua News Agency is the official press agency of the government of the People's Republic of China and the biggest center for collecting information and press conferences in the PRC. It is the largest news agency in the PRC, ahead of the China News Service...
has since reported that China's Ministry of Health has banned the procedure for schizophrenia and severely restricted the practice for other conditions.
Methods
Experimental ablation involves the drilling of holes in the skull of an animal and inserting an electrode or a small tube called a cannula into the brain using a stereotaxic apparatus. A brain lesion can be created by conducting electricity through the electrode which damages the targeted area of the brain. likewise, chemicals can be inserted in the cannula which also damages the area of interest. By comparing the prior behavior of the animal to after the lesion, the researcher can predict the function of damaged brain segment. Recently, LaserLaser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s have been shown to be effective in ablation of both cerebral and cerebellar
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
tissue. A laser called Er:YAG, for example, allows great precision in location and size of the lesion and causes little to no thermal damage to adjacent tissue.