Stereotactic surgery | |
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Other names | Stereotaxy |
Specialty | Neurosurgery |
Stereotactic surgery is a minimally invasive form of surgical intervention that makes use of a three-dimensional coordinate system to locate small targets inside the body and to perform on them some action such as ablation, biopsy, lesion, injection, stimulation, implantation, radiosurgery (SRS), etc.
In theory, any organ system inside the body can be subjected to stereotactic surgery. However, difficulties in setting up a reliable frame of reference (such as bone landmarks, which bear a constant spatial relation to soft tissues) mean that its applications have been, traditionally and until recently, limited to brain surgery. Besides the brain, biopsy and surgery of the breast are done routinely to locate, sample (biopsy), and remove tissue. Plain X-ray images (radiographic mammography), computed tomography, and magnetic resonance imaging can be used to guide the procedure.
Another accepted form of "stereotactic" is "stereotaxic". The word roots are stereo- , a prefix derived from the Greek word στερεός (stereos, "solid"), and -taxis (a suffix of Neo-Latin and ISV, derived from Greek taxis, "arrangement", "order", from tassein, "to arrange").
The surgery is used to treat various brain cancers, benign, and functional disorders of the brain. [1] This is sometimes combined with whole brain radiotherapy, and a 2021 systematic review found this combination led to the greatest improvement of survival for those with single brain metastasis. [2]
Amongst the malignant brain disorders are: brain metastasis and glioblastoma. [1] The benign brain disorders are: meningioma, cerebral arteriovenous malformation, vestibular schwannoma, and pituitary adenoma. [1] Functional disorders are: trigeminal neuralgia, Parkinson's disease, and epilepsy. [1]
Stereotactic surgery works on the basis of three main components:[ citation needed ]
Modern stereotactic planning systems 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 cylindrical coordinates system, also with three coordinates: angle, depth and antero-posterior (or axial) 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 or tomograph. In newborn human babies, the "soft spot" where the coronal and sagittal sutures meet (known as the fontanelle) becomes the bregma when this gap closes. [3]
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.
Currently, a number of manufacturers produce stereotactic devices fitted for neurosurgery in humans, for both brain and spine procedures, as well as for animal experimentation.
Stereotactic radiosurgery utilizes externally generated ionizing radiation to inactivate or eradicate defined targets in the head or spine without the need to make an incision. [5] This concept requires steep dose gradients to reduce injury to adjacent normal tissue while maintaining treatment efficacy in the target. [6] As a consequence of this definition, the overall treatment accuracy should match the treatment planning margins of 1–2 mm or better. [7] To use this paradigm optimally and treat patients with the highest possible accuracy and precision, all errors, from image acquisition over treatment planning to mechanical aspects of the delivery of treatment and intra-fraction motion concerns, must be systematically optimized. [8] To assure quality of patient care the procedure involves a multidisciplinary team consisting of a radiation oncologist, medical physicist, and radiation therapist. [9] [10] Dedicated, commercially available stereotactic radiosurgery programs are provided by the irrespective Gamma Knife, [11] CyberKnife, [12] and Novalis Radiosurgery [13] devices. [14]
Stereotactic radiosurgery provides an efficient, safe, and minimal invasive treatment alternative [15] for patients diagnosed with malignant, benign and functional indications in the brain and spine, including but not limited to both primary and secondary tumors. [16] Stereotactic radiosurgery is a well-described management option for most metastases, meningiomas, schwannomas, pituitary adenomas, arteriovenous malformations, and trigeminal neuralgia, among others. [17]
Irrespective of the similarities between the concepts of stereotactic radiosurgery and fractionated radiotherapy and although both treatment modalities are reported to have identical outcomes for certain indications, [18] the intent of both approaches is fundamentally different. The aim of stereotactic radiosurgery is to destroy target tissue while preserving adjacent normal tissue, where fractionated radiotherapy relies on a different sensitivity of the target and the surrounding normal tissue to the total accumulated radiation dose. [5] Historically, the field of fractionated radiotherapy evolved from the original concept of stereotactic radiosurgery following discovery of the principles of radiobiology: repair, reassortment, repopulation, and reoxygenation. [19] Today, both treatment techniques are complementary as tumors that may be resistant to fractionated radiotherapy may respond well to radiosurgery and tumors that are too large or too close to critical organs for safe radiosurgery may be suitable candidates for fractionated radiotherapy. [18]
A second, more recent evolution extrapolates the original concept of stereotactic radiosurgery to extra-cranial targets, most notably in the lung, liver, pancreas, and prostate. This treatment approach, entitled stereotactic body radiotherapy or SBRT, is challenged by various types of motion. [20] On top of patient immobilization challenges and the associated patient motion, extra-cranial lesions move with respect to the patient's position due to respiration, bladder and rectum filling. [21] Like stereotactic radiosurgery, the intent of stereotactic body radiotherapy is to eradicate a defined extra-cranial target. However, target motion requires larger treatment margins around the target to compensate for the positioning uncertainty. This in turn implies more normal tissue exposed to high doses, which could result in negative treatment side effects. As a consequence, stereotactic body radiotherapy is mostly delivered in a limited number of fractions, thereby blending the concept of stereotactic radiosurgery with the therapeutic benefits of fractionated radiotherapy. [22] To monitor and correct target motion for accurate and precise patient positioning prior and during treatment, advanced image-guided technologies are commercially available and included in the radiosurgery programs offered by the CyberKnife and Novalis communities. [23]
Functional neurosurgery comprises treatment of several disorders such as Parkinson's disease, hyperkinesia, 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 Meyers dissected or transected the head of the caudate nucleus in 1939, [24] and part of the putamen and globus pallidus. Attempts to abolish intractable pain were made with success by transection of the spinothalamic tract at spinal medullary level and further proximally, even at mesencephalic levels.[ citation needed ]
In 1939-1941 Putnam and Oliver tried to improve Parkinsonism and hyperkinesias by trying a series of modifications of the lateral and antero-lateral cordotomies. 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. This caused the patient's tremors to stop. From then on, thalamic lesions became the target point with more satisfactory results. [25]
More recent clinical applications can be seen [26] in surgeries used to treat Parkinson's disease, such as Pallidotomy or Thalamotomy (lesioning procedures), or Deep Brain Stimulation (DBS). [27] 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.[ citation needed ]
In Thalamotomy, a needle electrode is placed into the thalamus, and the patient must cooperate with tasks assigned to find the affected area- after this area 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.[ citation needed ]
In Pallidotomy, an almost identical procedure to thalamotomy, a small part of the pallidum is destroyed and 80% of patients see improvement in rigidity and hypokinesia and a tremor relief or improvement comes weeks after the procedure.[ citation needed ]
The stereotactic method was first published in 1908 by two British scientists, Victor Horsley, a physician and neurosurgeon, and Robert H. Clarke, a physiologist and was built by Swift & Son; the two scientists stopped collaborating after the 1908 publication. The Horsley–Clarke apparatus used a Cartesian (three-orthogonal axis) system. That device is in the Science Museum, London; a copy was brought to the US by Ernest Sachs and is in the Department of Neurosurgery at UCLA. Clarke used the original to do research that led to publications of primate and cat brain atlases. There is no evidence it was ever used in a human surgery. [28] [29] : 12 [30] The first stereotactic device designed for the human brain appears to have been an adaptation of the Horseley–Clarke frame built at Aubrey T. Mussen's behest by a London workshop in 1918, but it received little attention and does not appear to have been used on people. It was a frame made of brass. [29] : 12 [31]
The first stereotactic device used in humans was used by Martin Kirschner, for a method to treat trigeminal neuralgia by inserting an electrode into the trigeminal nerve and ablating it. He published this in 1933. [29] : 13 [32] : 420 [33]
In 1947 and 1949, two neurosurgeons working at Temple University in Philadelphia, Ernest A. Spiegel (who had fled Austria when the Nazis took over [28] ) and Henry T. Wycis, published their work on a device similar to the Horsley–Clarke apparatus in using a cartesian system; it was attached to the patient's head with a plaster cast instead of screws. Their device was the first to be used for brain surgery; they used it for psychosurgery. They also created the first atlas of the human brain, and used intracranial reference points, generated by using medical images acquired with contrast agents. [29] : 13 [32] : 72 [34]
The work of Spiegel and Wycis sparked enormous interest and research. [29] : 13 In Paris, Jean Talairach collaborated with Marcel David, Henri Hacaen, and Julian de Ajuriaguerra on a stereotactic device, publishing their first work in 1949 and eventually developing the Talairach coordinates. [28] [29] : 13 [32] : 93 In Japan, Hirotaro Narabayashi was doing similar work. [28]
In 1949, Lars Leksell published a device that used polar coordinates instead of cartesian, and two years later he published work where he used his device to target a beam of radiation into a brain. [29] : 13 [32] : 91 [35] [36] Leksell's radiosurgery 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 in 1972. [37]
In 1979, Russell A. Brown proposed a device, [38] now known as the N-localizer, [39] that enables guidance of stereotactic surgery using tomographic images that are obtained via medical imaging technologies such as X-ray computed tomography (CT), [40] magnetic resonance imaging (MRI), [41] or positron emission tomography (PET). [42] The N-localizer comprises a diagonal rod that spans two vertical rods to form an N-shape that allows tomographic images to be mapped to physical space. [43] This device became almost universally adopted by the 1980s [44] and is included in the Brown-Roberts-Wells (BRW), [45] Kelly-Goerss, [46] Leksell, [47] Cosman-Roberts-Wells (CRW), [48] Micromar-ETM03B, FiMe-BlueFrame, Macom, and Adeor-Zeppelin [49] stereotactic frames and in the Gamma Knife radiosurgery system. [44] An alternative to the N-localizer is the Sturm-Pastyr localizer [50] that is included in the Riechert-Mundinger and Zamorano-Dujovny stereotactic frames. [51]
Other localization methods also exist that do not make use of tomographic images produced by CT, MRI, or PET, but instead conventional radiographs. [52]
The stereotactic method has continued to evolve, and at present employs an elaborate mixture of image-guided surgery that uses computed tomography, magnetic resonance imaging and stereotactic localization.[ citation needed ]
In 1970, in the city of Buenos Aires, Argentina, Aparatos Especiales company, produced the first Stereotactic System in Latin America. Antonio Martos Calvo, together with Jorge Candia and Jorge Olivetti through the request of neurosurgeon Jorge Schvarc (1942-2019), developed an equipment based on the principle of Hitchcock Stereotactic System. The patient was seated in an adapted chair with two telescopic arms attached at it base, which fixed the stereotactic frame preventing the patient’s movement.
A double radiopaque ruler attached to the side of the frame made it possible to obtain the antero-posterior and latero-lateral X-ray images without the need of moving the radiopaque ruler. The thermal coagulation lesion was performed using tungsten monopole electrodes of 1,5mm of diameter (without temperature control) with a 3mm active tip, utilizing an electrical bipolar coagulator. The lesion size was previously determined by testing the electrode in egg albumin. Coagulation size was the result of the electrical coagulator power regulation and the application time of the radiofrequency. The first surgery performed with this system was a Trigeminal Nucleotractothomy. Jorge Schvarcz performed more than 700 functional surgeries until 1994 when, due to health problems he stopped exercising his profession. But the equipment developed kept improving on a neurosurgery history.
This was the beginning of the developing of technology to produce stereotactic devices in Latin America. This was the beginning of the first stereotactic manufacturer of Latin America – The Brazilian Micromar.
Stereotactic surgery is sometimes used to aid in several different types of animal research 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. [53] In rodents, the main applications of stereotactic surgery are to introduce fluids directly to the brain or to implant cannulae and microdialysis 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. [54] Surgery can also be used for microdialysis protocols to implant and tether the dialysis probe and guide cannula. [55]
Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and peripheral nervous system.
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant (cancerous) tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secondary tumors, which most commonly have spread from tumors located outside the brain, known as brain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the size of the tumor and the part of the brain that is involved. Where symptoms exist, they may include headaches, seizures, problems with vision, vomiting and mental changes. Other symptoms may include difficulty walking, speaking, with sensations, or unconsciousness.
Deep brain stimulation (DBS) is a surgical procedure that implants a neurostimulator and electrodes which sends electrical impulses to specified targets in the brain responsible for movement control. The treatment is designed for a range of movement disorders such as Parkinson's disease, essential tremor, and dystonia, as well as for certain neuropsychiatric conditions like obsessive-compulsive disorder (OCD) and epilepsy. The exact mechanisms of DBS are complex and not entirely clear, but it is known to modify brain activity in a structured way.
A vestibular schwannoma (VS), also called acoustic neuroma, is a benign tumor that develops on the vestibulocochlear nerve that passes from the inner ear to the brain. The tumor originates when Schwann cells that form the insulating myelin sheath on the nerve malfunction. Normally, Schwann cells function beneficially to protect the nerves which transmit balance and sound information to the brain. However, sometimes a mutation in the tumor suppressor gene, NF2, located on chromosome 22, results in abnormal production of the cell protein named Merlin, and Schwann cells multiply to form a tumor. The tumor originates mostly on the vestibular division of the nerve rather than the cochlear division, but hearing as well as balance will be affected as the tumor enlarges.
Lars Leksell was a Swedish physician and Professor of Neurosurgery at the Karolinska Institute in Stockholm, Sweden. He was the inventor of radiosurgery.
Radiosurgery is surgery using radiation, that is, the destruction of precisely selected areas of tissue using ionizing radiation rather than excision with a blade. Like other forms of radiation therapy, it is usually used to treat cancer. Radiosurgery was originally defined by the Swedish neurosurgeon Lars Leksell as "a single high dose fraction of radiation, stereotactically directed to an intracranial region of interest".
Image-guided surgery (IGS) is any surgical procedure where the surgeon uses tracked surgical instruments in conjunction with preoperative or intraoperative images in order to directly or indirectly guide the procedure. Image guided surgery systems use cameras, ultrasonic, electromagnetic or a combination of fields to capture and relay the patient's anatomy and the surgeon's precise movements in relation to the patient, to computer monitors in the operating room or to augmented reality headsets. This is generally performed in real-time though there may be delays of seconds or minutes depending on the modality and application.
Elekta is a global Swedish company that develops and produces radiation therapy and radiosurgery-related equipment and clinical management for the treatment of cancer and brain disorders. Elekta has a global presence in more than 120 countries, with over 40 offices around the world and about 4,700 employees.
John R. Adler is an American neurosurgeon and medical device entrepreneur.
Tomotherapy is a type of radiation therapy treatment machine. In tomotherapy a thin radiation beam is modulated as it rotates around the patient, while they are moved through the bore of the machine. The name comes from the use of a strip-shaped beam, so that only one “slice” of the target is exposed at any one time by the radiation. The external appearance of the system and movement of the radiation source and patient can be considered analogous to a CT scanner, which uses lower doses of radiation for imaging. Like a conventional machine used for X-ray external beam radiotherapy, a linear accelerator generates the radiation beam, but the external appearance of the machine, the patient positioning, and treatment delivery is different. Conventional linacs do not work on a slice-by-slice basis but typically have a large area beam which can also be resized and modulated.
The CyberKnife system is a radiation therapy device manufactured by Accuray. The system is used to deliver radiosurgery for the treatment of benign tumors, malignant tumors and other medical conditions.
Stereotactic radiation therapy (SRT), also called stereotactic external-beam radiation therapy and stereotaxic radiation therapy, is a type of external radiation therapy that uses special equipment to position the patient and precisely deliver radiation to a tumor. The total dose of radiation is divided into several smaller doses given over several days. Stereotactic radiation therapy is used to treat brain tumors and other brain disorders. It is also being studied in the treatment of other types of cancer, such as lung cancer. What differentiates Stereotactic from conventional radiotherapy is the precision with which it is delivered. There are multiple systems available, some of which use specially designed frames which physically attach to the patient's skull while newer more advanced techniques use thermoplastic masks and highly accurate imaging systems to locate the patient. The end result is the delivery of high doses of radiation with sub-millimetre accuracy.
Patient registration is used to correlate the reference position of a virtual 3D dataset gathered by computer medical imaging with the reference position of the patient. This procedure is crucial in computer assisted surgery, in order to insure the reproducitibility of the preoperative registration and the clinical situation during surgery. The use of the term "patient registration" out of this context can lead to a confusion with the procedure of registering a patient into the files of a medical institution.
Central neurocytoma (CNC) is an extremely rare, ordinarily benign intraventricular brain tumour that typically forms from the neuronal cells of the septum pellucidum. The majority of central neurocytomas grow inwards into the ventricular system forming interventricular neurocytomas. This leads to two primary symptoms of CNCs, blurred vision and increased intracranial pressure. Treatment for a central neurocytoma typically involves surgical removal, with an approximate 1 in 5 chance of recurrence. Central neurocytomas are classified as a grade II tumor under the World Health Organization's classification of tumors of the nervous system.
James R. Doty, M.D., FACS, FICS, FAANS is a clinical professor of neurosurgery at Stanford University and founder and director of the Center for Compassion and Altruism Research and Education, an affiliate of the Stanford Neurosciences Institute. He is the author of a self-help book called Into the Magic Shop: A Neurosurgeon's Quest to Discover the Mysteries of the Brain and the Secrets of the Heart. Doty is also the Senior Editor of the Oxford Handbook of Compassion Science (2017).
The N-localizer is a device that enables guidance of stereotactic surgery or radiosurgery using tomographic images that are obtained via computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET). The N-localizer comprises a diagonal rod that spans two vertical rods to form an N-shape and permits calculation of the point where a tomographic image plane intersects the diagonal rod. Attaching three N-localizers to a stereotactic instrument allows calculation of three points where a tomographic image plane intersects three diagonal rods. These points determine the spatial orientation of the tomographic image plane relative to the stereotactic frame.
Jefferson Hospital for Neuroscience is a hospital in Center City Philadelphia, affiliated with Thomas Jefferson University and Thomas Jefferson University Hospital in Philadelphia. The hospital focuses on treating brain-related diseases and disorders. It is the only hospital of its kind in the Philadelphia area.
Subramanian Kalyanaraman is an Indian neurosurgeon and a former head of the Department of Neurosurgery at Apollo Hospitals, Chennai. He was known for his pioneering techniques in stereotactic surgery and is an elected fellow of a number of science and medical academies including the National Academy of Medical Sciences and the Indian Academy of Sciences. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Medical Sciences in 1969.
Amygdalotomy is a form of psychosurgery which involves the surgical removal or destruction of the amygdala, or parts of the amygdala. It is usually a last-resort treatment for severe aggressive behavioral disorders and similar behaviors including hyperexcitability, violent outbursts, and self-mutilation. The practice of medical amygdalotomy typically involves the administration of general anesthesia and is achieved through the application of cranial stereotactic surgery to target regions of the amygdala for surgical destruction. While some studies have found stereotactic amygdalotomy in humans to be an effective treatment for severe cases of intractable aggressive behavior that has not responded to standard treatment methods, other studies remain inconclusive. In most cases of amygdalectomy in humans, there is no substantial evidence of impairment in overall cognitive function, including intelligence and working memory, however, deficits in specific areas of memory have been noted pertaining to the recognition and emotional interpretation of facial stimuli. This is because there are specialized cells in the amygdala which attend to facial stimuli.
Konstantin Slavin is a Professor and Head of the Department of Stereotactic and functional neurosurgery at the University of Illinois College of Medicine. He is a former president of the American Society for Stereotactic and functional neurosurgery and current vice-president of the World Society for Stereotactic and Functional Neurosurgery. His specialties include Aneurysm, Brain surgery, Brain Tumor, Cerebrovascular Disorders, Craniotomy, Dystonia, Essential Tremor, Facial Nerve Pain, Facial Pain, Glioblastoma, Headache disorders, Laminectomy, Lower back pain, Movement Disorders, Multiple Sclerosis, Neck Pain, Neurosurgery, Neurosurgical Procedures, Pain, Parkinson Disease, Spinal Cord Injuries, and Stroke.
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