Stereotaxic surgery
Stereotaxic surgery, also known as stereotactic surgery, is a minimally invasive surgical technique that utilizes three-dimensional coordinate systems to precisely target specific areas within the body for various medical interventions, including biopsies, injections, and radiosurgery. This method is particularly advantageous for treating small tumors, as it minimizes damage to surrounding healthy tissues. The roots of stereotaxic surgery can be traced back to the early 20th century, but it gained significant traction in the late 1940s when neurosurgeons at Temple University pioneered its application in human patients.
The advancement of imaging technologies, such as X-rays and MRIs, has been crucial for enhancing the accuracy of this technique, allowing surgeons to align instruments with the patient's anatomy effectively. In modern practice, stereotaxic surgery has evolved to include noninvasive procedures like radiosurgery, which employs focused beams of radiation—such as those from the Gamma Knife and CyberKnife—to treat tumors without incisions. This approach has led to quicker recovery times for patients, making it a valuable option in various fields, including oncology and neurology. Additionally, stereotaxic techniques are utilized to alleviate symptoms in conditions like Parkinson's disease by blocking specific electrical signals in the brain. Overall, stereotaxic surgery represents a significant advancement in precise surgical interventions with a focus on patient safety and recovery.
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Stereotaxic surgery
Stereotaxic surgery, also called stereotactic surgery, is a minimally invasive form of surgery in which three-dimensional systems of coordinates are used to chart the locations of precise spots in the body so surgeons can perform actions on them such as injections, stimulations, biopsies, or radiosurgery. Stereotaxic surgery pinpoints affected areas of the body for treatment so surrounding tissue is not damaged in the process. This type of surgery is especially useful in the treatment of small tumors in the body, for these can be sampled, tested, and irradiated without affecting nearby healthy areas of the body.
Neurosurgeons at Temple University in Pennsylvania were the first to use stereotaxic surgical techniques on human patients in the late 1940s. Stereotaxic surgery greatly advanced after that. In the twenty-first century, it is used for a variety of surgeries, notably the entirely noninvasive radiosurgery, which uses beams of radiation to destroy harmful tumors in the body without making incisions with a knife. Stereotaxic machines commonly used to irradiate tumors include the Gamma Knife and CyberKnife.
Background
Stereotaxic surgery began in rudimentary form in the United Kingdom in 1908. That year, neurosurgeon Victor Horsley and mathematician Robert Clarke published information about a device they had used to direct electricity into the cerebellum of a monkey's brain, thereby creating a damaged area of tissue called a lesion.
Horsley and Clarke's device had used Cartesian coordinates to plot the exact point of the monkey's brain the scientists wanted to affect. Cartesian coordinates (such as x, y, and z) show exactly where certain points are on the planes created by two fixed lines called axes. Clarke patented his device for use in human surgery, but it was never adopted for this purpose. This was because medical technology was not yet advanced enough to plot accurate coordinates in human brains.
Over the next few decades, developments in photography and existing X-ray technology allowed doctors to map the human brain more accurately. These X-rays showed surgeons the dimensions of human brains so they could identify the locations of tumors and other problems in relation to the known dimensions. By the late 1940s, this technology had advanced so greatly that doctors Ernst Spiegel and Henry Wycis at Temple University in Philadelphia, Pennsylvania, began testing their own stereotaxic methods on people.
In 1947 Spiegel and Wycis developed the technique of injecting X-ray contrast, or dye, into a patient's spinal cord and then taking X-rays of the patient's brain. The contrast that had traveled to the brain allowed the doctors to plot coordinates deep in the brain rather than simply on the patient's skull. Ultimately, Spiegel and Wycis used these coordinates to locate the exact areas of patients' brains that were affected by tumors or other issues and operate on them using electrodes attached to plastic caps placed on patients' heads.
Spiegel and Wycis publicized their achievement, and neurosurgeons worldwide started traveling to Temple to learn from them. The machines Spiegel and Wycis had used for their first stereotaxic surgery were not yet commercial products. The other neurosurgeons had to copy Spiegel and Wycis's designs and then build their own devices to conduct the surgery themselves. Tens of thousands of stereotaxic surgeries had been performed by 1965. Stereotaxic technology advanced much further over the next several decades, making the process more widely available and useful for a range of surgical procedures.
Overview
Image registration is the process that allows stereotaxic surgery to succeed at all. It involves transposing different images into one coordinate system so surgeons can accurately locate the anatomical points in the patients' bodies where the surgeries will occur. Perfect accuracy is vital in stereotaxic surgery, for electricity or radiation beams directed at the wrong part of the brain or other body part could damage healthy tissue.
Surgeons combine X-ray images of the area of the body to be operated on with the existing coordinate system of the stereotaxic device to align the instruments that will perform the operation. Once the device's instruments are perfectly coordinated with the patient's actual medical images, the surgeons can safely perform the procedure.
In the twenty-first century, stereotaxic surgery is used for a variety of operations. Brain surgery is one of the most common applications. Magnetic resonance imaging (MRI) scans of the brain allow surgeons to direct their instruments to the exact place in the head where a tumor is. A stereotaxic frame is attached to the patient's head, and a small hole is made in the skull for the operation. This method is often safer for removing a tumor than conducting the surgery manually.
Another type of stereotaxic surgery is radiosurgery, also used for eliminating small cancerous tumors in the body. Unlike traditional surgeries, radiosurgery is noninvasive, meaning no incisions are made in the body. Radiosurgery employs several beams of radiation to attack tumors. The radiation corrupts the DNA in the tumor, which prevents the tumor's cells from replicating and thus causes the tumor to shrink.
A radiosurgery machine called the Gamma Knife can be used to irradiate brain tumors. Only one session with the Gamma Knife is generally needed for irradiating tumors in the brain and spine. Radiation oncologists, or doctors who treat cancer, and sometimes neurosurgeons are present for Gamma Knife treatment. They determine the exact dosage of radiation that is appropriate for the procedure. A different kind of radiosurgery device called the CyberKnife is used to treat cancer elsewhere in the body. It usually takes several sessions for the CyberKnife to treat cancer in the lungs, liver, or other areas of the body. The use of radiosurgery to treat cancer in parts of the body other than the brain is known as stereotaxic body therapy.
Because radiosurgery is noninvasive, patients who have had the procedure may resume their normal activities almost immediately afterward. Side effects of radiosurgery include soreness and hair loss in the area of treatment, headaches, nausea and vomiting, difficulty swallowing, and trouble digesting, depending on the area of surgery. Radiosurgery can also sometimes damage nearby healthy cells. This may lead to the development of additional cancers later in life. Patients who have had radiosurgery should have regular checkups with their oncologists.
Stereotaxic surgery is also useful for patients with Parkinson's disease. Surgeons use stereotaxic techniques to block certain electrical signals in the brain. With these signals blocked, Parkinson's patients may be relieved of symptoms such as tremors and muscle stiffness.
Bibliography
"Cyberknife vs Gamma Knife." Pasadena CyberKnife Center, pasadenacyberknife.com/cyberknife-vs-gamma-knife. Accessed 11 Oct. 2017.
"Deep Brain Stimulation." National Parkinson Foundation, www.parkinson.org/understanding-parkinsons/treatment/surgery-treatment-options/Deep-Brain-Stimulation. Accessed 11 Oct. 2017.
Khan, Fahd R., and Jaimie M. Henderson. "Deep Brain Stimulation Surgical Techniques." Brain Stimulation, edited by Andres M. Lozano and Mark Hallett, Elsevier, 2013, 27–29.
"Stereotactic Brain Surgery." University of Rochester Medical Center, www.urmc.rochester.edu/neurosurgery/for-patients/treatments/stereotactic-brain-surgery.aspx. Accessed 11 Oct. 2017.
"Stereotactic Radiosurgery." Mayo Clinic, www.mayoclinic.org/tests-procedures/stereotactic-radiosurgery/home/ovc-20130212. Accessed 11 Oct. 2017.
"Stereotactic Radiosurgery (SRS)." Healthline, www.healthline.com/health/stereotactic-radiosurgery#overview1. Accessed 11 Oct. 2017.
"Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT)." Radiological Society of North America,www.radiologyinfo.org/en/info.cfm?pg=stereotactic. Accessed 11 Oct. 2017.
"Stereotactic Surgery in Parkinson Disease." Medscape, emedicine.medscape.com/article/1153743-overview. Accessed 11 Oct. 2017.
Walter, Benjamin L., et al. "Current Neurosurgical Treatments for Parkinson's Disease: Where Did They Come From?" From Neuroscience to Neurology: Neuroscience, Molecular Medicine, and the Therapeutic Transformation of Neurology, edited by Stephen Waxman, Elsevier Academic, 2005, 161–162.