Stereotactic guided insertion of DBS electrodes in neurosurgery
Neurosurgery (or neurological surgery) 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, spinal cord, peripheral nerves, and extra-cranial cerebrovascular system.
Education and training
In different countries, there are different requirements for an individual to legally practice neurosurgery, and there are varying methods through which they must be educated. In most countries, neurosurgeon training requires a minimum period of seven years after graduating from medical school.
In the United States, a neurosurgeon must generally complete four years of undergraduate education, four years of medical school, and seven years of residency (PGY-1-7). Most, but not all, residency programs have some component of basic science or clinical research. Neurosurgeons may pursue additional training in the form of a fellowship, after residency or in some cases, as a senior resident. These fellowships include pediatric neurosurgery, trauma/neurocritical care, functional and stereotactic surgery, surgical neuro-oncology, radiosurgery, neurovascular surgery, skull-base surgery, peripheral nerve and spine surgery. In the U.S., neurosurgery is considered a highly competitive specialty composed of 0.6% of all practicing physicians.
In the United Kingdom, students must gain entry into medical school. MBBS qualification (Bachelor of Medicine, Bachelor of Surgery) takes four to six years depending on the student's route. The newly qualified physician must then complete foundation training lasting two years; this is a paid training program in a hospital or clinical setting covering a range of medical specialties including surgery. Junior doctors then apply to enter the neurosurgical pathway. Unlike most other surgical specialties, it currently has its own independent training pathway which takes around eight years (ST1-8); before being able to sit for consultant exams with sufficient amounts of experience and practice behind them. Neurosurgery remains consistently amongst the most competitive medical specialties in which to obtain entry.
Main divisions of neurosurgery
General neurosurgery involves most neurosurgical conditions including neuro-trauma and other neuro-emergencies such as intracranial hemorrhage. Most level 1 hospitals have this kind of practice.
Specialized branches have developed to cater to special and difficult conditions. These specialized branches co-exist with general neurosurgery in more sophisticated hospitals. To practice advanced specialization within neurosurgery, additional higher fellowship training of one to two years is expected from the neurosurgeon. Some of these divisions of neurosurgery are:
- vascular neurosurgery and endovascular neurosurgery
- stereotactic neurosurgery, functional neurosurgery, and epilepsy surgery (the latter includes partial or total corpus callostomy- severing part or all of the corpus callosum to stop or lessen seizure spread and activity, and the surgical removal of functional- physiological- and/or anatomical pieces or divisions of the brain, called epileptic foci, that are operable and that are causing seizures, and also the more radical and very, very rare partial or total lobectomy, or even hemispherectomy- the removal of part or all of one of the lobes, or one of the cerebral hemispheres of the brain; those two procedures, when possible, are also very, very rarely used in oncological neurosurgery or to treat very severe neurological trauma, such as stab or gunshot wounds to the brain)
- oncological neurosurgery (also called neurosurgical oncology; includes pediatric oncological neurosurgery; treatment of benign and malignant central and peripheral nervous system cancers and pre-cancerous lesions in adults and children (including, among others, glioblastoma multiforme and other gliomas, brain stem cancer, astrocytoma, pontine glioma, medulloblastoma, spinal cancer, tumors of the meninges and intracranial spaces, secondary metastases to the brain, spine, and nerves, and peripheral nervous system tumors)
- skull base surgery
- spinal neurosurgery
- peripheral nerve surgery
- pediatric neurosurgery (for cancer, seizures, bleeding, stroke, cognitive disorders or congenital neurological disorders)
- neuropsychiatric surgery (neurosurgery for the treatment of adult or pediatric mental illnesses)
- geriatric neurosurgery (for the treatment of neurological disorders and dementias and mental impairments due to age, but not due to a stroke, seizure, tumor, concussion, or neurovascular cause- namely, Parkinsonism, Alzheimer's, multiple sclerosis, and similar disorders)
The neuropathology confronted by neurosurgeons could be either congenital, acquired, traumatic, due to infection, or neoplastic or degenerative conditions. Conditions like congenital hydrocephalus, pediatric cancers and myelomeningocele are encountered in children. Trauma with head or spine injury and bleeds due to arteriovenous malformation are encountered in young adults. Degenerative spine disease, aneurysm bleeds and Parkinson's disease are encountered in much older patients. The science of neuropathology is a well developed branch of pathology.
Neuroanesthesia is a highly developed science that is linked to neurosurgery. This branch of medicine plays a very important part in day-to-day neurosurgery.
Neuroradiology plays a key role not only in diagnosis but also in the operative phase of neurosurgery.
Neuroradiology methods are used in modern neurosurgery diagnosis and treatment. They include computer assisted imaging computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), magnetoencephalography (MEG), and stereotactic radiosurgery. Some neurosurgery procedures involve the use of intra-operative MRI and functional MRI.
In conventional open surgery the neurosurgeon opens the skull, creating a large opening to access the brain. Techniques involving smaller openings with the aid of microscopes and endoscopes are now being used as well. Methods that utilize small craniotomies in conjunction with high-clarity microscopic visualization of neural tissue offer excellent results. However, the open methods are still traditionally used in trauma or emergency situations. Principles of Neurosurgery-Rengachari, Ellenbogen,  Neurotrauma and Critical Care of the Brain-Jallo, Loftus.''
Microsurgery is utilized in many aspects of neurological surgery. Microvascular techniques are used in EC-IC bypass surgery and in restoration carotid endarterectomy. The clipping of an aneurysm is performed under microscopic vision. minimally-invasive spine surgery utilizes microscopes or endoscopes. Procedures such as microdiscectomy, laminectomy, and artificial disc replacement rely on microsurgery.
Using stereotaxy neurosurgeons can approach a minute target in the brain through a minimal opening. This is used in functional neurosurgery where electrodes are implanted or gene therapy is instituted with high level of accuracy as in the case of Parkinson's disease or Alzheimer's disease. Using the combination method of open and stereotactic surgery, intraventricular hemorrhages can potentially be evacuated successfully. Conventional surgery using image guidance technologies is also becoming common and is referred to as surgical navigation, computer assisted surgery, navigated surgery, stereotactic navigation. Similar to a car or mobile Global Positioning System (GPS), image guided surgery systems, like Curve Image Guided Surgery and StealthStation, use cameras or electromagnetic 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. These sophisticated computerized systems are used before and during surgery to help orient the surgeon with three-dimensional images of the patient’s anatomy including the tumor.
Minimally invasive endoscopic surgery is commonly utilized by neurosurgeons when appropriate. Techniques such as endoscopic endonasal surgery are used in pituitary tumors, craniopharyngiomas, chordomas, and the repair of cerebrospinal fluid leaks. Ventricular endoscopy is used in the treatment of intraventricular bleeds, hydrocephalus, colloid cyst and neurocysticercosis. Endonasal endoscopy is at times carried out with neurosurgeons and ENT surgeons working together as a team.
Repair of craniofacial disorders and disturbance of cerebrospinal fluid circulation is done by neurosurgeons who also occasionally team up with maxillofacial and plastic surgeons. Cranioplasty for craniosynostosis is performed by pediatric neurosurgeons with or without plastic surgeons.
Neurosurgeons are involved in stereotactic radiosurgery along with radiation oncologists in tumor and AVM treatment. Radiosurgical methods such as Gamma knife, Cyberknife and Novalis Radiosurgery are used as well.
Endovascular Neurosurgery utilize endovascular image guided procedures for the treatment of aneurysms, AVMs, carotid stenosis, strokes, and spinal malformations, and vasospasms. Techniques such as angioplasty, stenting, clot retrieval, embolization, and diagnostic angiography are endovascular procedures.
A common procedure performed in neurosurgery is the placement of Ventriculo-Peritoneal Shunt (VP Shunt). In pediatric practice this is often implemented in cases of congenital hydrocephalus. The most common indication for this procedure in adults is Normal Pressure Hydrocephalus (NPH).
Neurosurgery of the spine covers the cervical, thoracic and lumbar spine. Some indications for spine surgery include spinal cord compression resulting from trauma, arthritis of the spinal discs, or spondylosis. In cervical cord compression, patients may have difficulty with gait, balance issues, and/or numbness and tingling in the hands or feet. Spondylosis is the condition of spinal disc degeneration and arthritis that may compress the spinal canal. This condition can often result in bone-spurring and disc herniation. Power drills and special instruments are often used to correct any compression problems of the spinal canal. Disc herniations of spinal vertebral discs are removed with special rongeurs. This procedure is known as a discectomy. Generally once a disc is removed it is replaced by an implant which will create a bony fusion between vertebral bodies above and below. Instead, a mobile disc could be implanted into the disc space to maintain mobility. This is commonly used in cervical disc surgery. At times instead of disc removal a Laser discectomy could be used to decompress a nerve root. This method is mainly used for lumbar discs. Laminectomy is the removal of the Lamina portion of the vertebrae of the spine in order to make room for the compressed nerve tissue. Radiology assisted spine surgery uses minimally-invasive procedures. They include the techniques of vertebroplasty and kyphoplasty in which certain types of spinal fractures are managed. Principles of Neurosurgery- Rengachary, Ellenbogen Potentially unstable spines will need spine fusions. At present these procedures include complex instrumentation. Spine fusions could be performed as open surgery or as minimally invasive surgery. Anterior cervical diskectomy and fusion is a common surgery that is performed for disc disease of cervical spine.  Core Techniques in Operative Neurosurgery - Jandial, McCormick, Black However, each method described above may not work in all patients. Therefore, careful selection of patients for each procedure is important. It has to be noted that if there is prior permanent neural tissue damage spinal surgery may not take away the symptoms.
Surgery for chronic pain is a sub branch of functional neurosurgery. Some of the techniques include implantation of deep brain stimulators, spinal cord stimulators, peripheral stimulators and pain pumps.  Neurosurgical Operative Atlas, Philip A. Starr, Nicholas M. Barbaro, Paul S. Larson
Surgery of the peripheral nervous system is also possible, and includes the very common procedures of carpal tunnel decompression and peripheral nerve transposition. Numerous other types of nerve entrapment conditions and other problems with the peripheral nervous system are treated as well.
Other conditions treated by neurosurgeons include:
- Meningitis and other central nervous system infections including abscesses
- Spinal disc herniation
- Cervical spinal stenosis and Lumbar spinal stenosis
- Head trauma (brain hemorrhages, skull fractures, etc.)
- Spinal cord trauma
- Traumatic injuries of peripheral nerves
- Tumors of the spine, spinal cord and peripheral nerves
- Intracerebral hemorrhage, such as subarachnoid hemorrhage, interdepartmental, and intracellular hemorrhages
- Some forms of drug-resistant epilepsy
- Some forms of movement disorders (advanced Parkinson's disease, chorea) – this involves the use of specially developed minimally invasive stereotactic techniques (functional, stereotactic neurosurgery) such as ablative surgery and deep brain stimulation surgery
- Intractable pain of cancer or trauma patients and cranial/peripheral nerve pain
- Some forms of intractable psychiatric disorders
- Vascular malformations (i.e., arteriovenous malformations, venous angiomas, cavernous angiomas, capillary telangectasias) of the brain and spinal cord
- Moyamoya disease
- Sir Victor Horsley – known as the first neurosurgeon
- Hermann Schloffer invented transsphenoidal surgery in 1907
- Harvey Cushing – known as the father of modern neurosurgery
- Gazi Yaşargil – known as the father of microneurosurgery
- Ludvig Puusepp – known as one of the founding fathers of modern neurosurgery, world's first professor of neurosurgery
- Walter Dandy – known as one of the founding fathers of modern neurosurgery
- Hirotaro Narabayashi – a pioneer of stereotaxic neurosurgery
- Alim-Louis Benabid – known as one of the developers of deep brain stimulation surgery for movement disorder
- Wilder Penfield – known as one of the founding fathers of modern neurosurgery, and pioneer of epilepsy neurosurgery
- Joseph Ransohoff – known for his pioneering use of medical imaging and catheterization in neurosurgery, and for founding the first neurosurgery intensive care unit
- Robert F. Spetzler – The most prolific vascular neurosurgeon in the world and director of the Barrow Neurological Institute
- Lars Leksell – Swedish neurosurgeon who developed the Gamma Knife
- Ben Carson – renowned pediatric neurosurgeon at Johns Hopkins Hospital and presidential candidate, pioneer in hemispherectomy, and pioneer in the separation of craniopagus twins (joined at the head)
- John R. Adler – Stanford University neurosurgeon who invented the CyberKnife
- Wirginia Maixner – pediatric neurosurgeon at Melbourne's Royal Children's Hospital. Primarily known for separating conjoined Bangladeshi twins, Trishna and Krishna
- Sid Watkins – world-renowned neurosurgeon who served for 26 years as the Formula One Safety and Medical Delegate (race doctor)
- Frank Henderson Mayfield – invented the Mayfield skull clamp
- Ayub K. Ommaya – invented the Ommaya reservoir
- Richard N.W. Wohns – invented interspinous implant and implantation instrument
- American Academy of Neurological and Orthopaedic Surgeons - The American Academy of Neurological and Orthopaedic Surgeons (AANOS) also known as "The Academy" is a scientific and educational association of orthopedists and neurosurgeons that was founded in the US in 1976 in order to improve the quality of care provided to patients in these two major sub-specialty fields. This has been accomplished through setting high standards for training, credentialing and continuous surgical education as well as in the subsequent practice of orthopaedics and neurosurgery. The Academy’s standards for education and training of its Diplomates meets or exceeds the requirements of other organizations. Diplomates are required to re-certify every five years and present evidence of participation in continuing medical education and ongoing training in order to obtain this re-certification.
- American Association of Neurological Surgeons
- Congress of Neurological Surgeons
- Polyaxial screw
- AANS – Patient Information
- "The society of British neurological surgeons". Archived from the original on January 20, 2011. Retrieved 2011-03-11.
- Cyber Museum of Neurosurgery
- Stereotactic Radiosurgery Program | UCLA Neurosurgery
- Neuroradiology – Information for Patients & Referring Physicians
- The Brain that Changed Everything by Luke Dittrich – Esquire, November 2010
- European Association of Neurosurgical Societies - website
- Mediwikis website - A learning community for medical students