Awake craniotomy | |
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Specialty | neurology |
Awake craniotomy is a neurosurgical technique and type of craniotomy that allows a surgeon to remove a brain tumor while the patient is awake to avoid brain damage. During the surgery, the neurosurgeon performs cortical mapping to identify vital areas, called the "eloquent brain", that should not be disturbed while removing the tumor.
A particular use for awake craniotomy is mapping the cortex to avoid causing language or movement deficits with the surgery. It is more effective than surgeries performed under general anesthesia in avoiding complications. Awake craniotomy can be used in a variety of brain tumors, including glioblastomas, gliomas, and brain metastases. [1] [2] [3] [4] It can also be used for epilepsy surgery to remove a larger amount of the section of tissue causing the seizures without damaging function, for deep brain stimulation placement, or for pallidotomy. [2] [4] Awake craniotomy has increased the scope of tumors that are considered resectable (treatable by surgery) and in general, reduces recovery time. [2] [5] Awake craniotomy is also associated with reduced iatrogenic brain damage after surgery. [6]
Before an awake craniotomy begins for tumor or epilepsy surgery, the patient is given anxiolytic medications. The patient is then positioned in a neurosurgical head restraint that holds the head completely still and given general anesthesia. The anesthesiologist will then use local anesthetics like lidocaine or bupivacaine to numb the skin and bone of the head and neck. The craniotomy begins with a surgeon removing an area of the skull over the tumor and cutting into the meninges, the membranes that protect the brain. Before removing any brain tissue, the patient is awakened and the neurosurgeon creates a cortical map, using a small electrical stimulation device to observe the changes in the patient's condition when an area is stimulated. If an area is stimulated and the patient moves or loses some ability, like speech, the surgeon knows that the area is vital and cannot be removed or cut through to access a tumor. [1] During the procedure, the surgeon, anesthesiologist, and other surgical personnel speak to the patient and may ask them questions [7] . A speech and language pathologist and/or a neuropsychologist monitor the patient carefully while the patient performs different types of language/other cognitive tasks. The golden standard for intraoperative tasks is object naming, but there are a number of different tasks that can be used during awake surgery. [4] [8] [9]
There are two variations on the technique: asleep-awake-asleep (AAA), and monitored anesthetic care (MAC), also called conscious sedation. In an AAA surgery, the patient is only awake during the cortical mapping; whereas in an MAC surgery the patient is awake the entire time. [5]
The procedure for deep brain stimulation placement is similar, though instead of skull being removed, a burr hole is drilled for the electrodes instead and the MAC surgery is more common. [5]
The complications of awake craniotomy are similar to complications from brain surgery done under general anesthesia – seizures during the operation, nausea, vomiting, loss of motor or speech function, hemodynamic instability (hypertension, hypotension, or tachycardia), cerebral edema, hemorrhage, stroke or air embolism, and death. [1] [5] Seizures are the most common complication. [4]
Awake surgery in gliomas is known to cause postoperative language and other cognitive impairments, however the frequency and severity is not well established due to e.g. differences in patient selection, test methods and how deficits are defined [10] [11] . In the sub-acute phase (1-10 days postoperatively) the difficulties may be quite severe, but gradual recovery is expected. [12]
There are patients for whom an awake craniotomy is not appropriate. Those with anxiety disorders, claustrophobia, schizophrenia, or low pain tolerance are poor candidates for an awake surgery because any treatment of a psychological crisis would harm the procedure and could harm the patient. [5] Additionally, patients with obstructive sleep apnea are usually considered poor candidates due to problems with oxygenation, ventilation, and a potentially difficult airway. [13]
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.
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.
Awareness under anesthesia, also referred to as intraoperative awareness or accidental awareness during general anesthesia (AAGA), is a rare complication of general anesthesia where patients regain varying levels of consciousness during their surgical procedures. While anesthesia awareness is possible without resulting in any long-term memory of the experience, it is also possible for victims to have awareness with explicit recall, where they can remember the events related to their surgery.
The Wada test, also known as the intracarotid sodium amobarbital procedure (ISAP) or Wada-Milner Test, establishes cerebral language and memory representation of each hemisphere.
Hemispherectomy is a surgery that is performed by a neurosurgeon where an unhealthy hemisphere of the brain is disconnected or removed. There are two types of hemispherectomy. Functionalhemispherectomy refers to when the diseased brain is simply disconnected so that it can no longer send signals to the rest of the brain and body. Anatomical hemispherectomy refers to when not only is there disconnection, but also the diseased brain is physically removed from the skull. This surgery is mostly used as a treatment for medically intractable epilepsy, which is the term used when anti-seizure medications are unable to control seizures.
A craniotomy is a surgical operation in which a bone flap is temporarily removed from the skull to access the brain. Craniotomies are often critical operations, performed on patients who are suffering from brain lesions, such as tumors, blood clots, removal of foreign bodies such as bullets, or traumatic brain injury, and can also allow doctors to surgically implant devices, such as deep brain stimulators for the treatment of Parkinson's disease, epilepsy, and cerebellar tremor. The procedure is also used in epilepsy surgery to remove the parts of the brain that are causing epilepsy.
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.
The study of neurology and neurosurgery dates back to prehistoric times, but the academic disciplines did not begin until the 16th century. The formal organization of the medical specialties of neurology and neurosurgery are relatively recent, taking place in the place in Europe and the United States only in the 20th century with the establishment of professional societies distinct from internal medicine, psychiatry and general surgery. From an observational science they developed a systematic way of approaching the nervous system and possible interventions in neurological disease.
Intraoperative neurophysiological monitoring (IONM) or intraoperative neuromonitoring is the use of electrophysiological methods such as electroencephalography (EEG), electromyography (EMG), and evoked potentials to monitor the functional integrity of certain neural structures during surgery. The purpose of IONM is to reduce the risk to the patient of iatrogenic damage to the nervous system, and/or to provide functional guidance to the surgeon and anesthesiologist.
Electrocorticography (ECoG), a type of intracranial electroencephalography (iEEG), is a type of electrophysiological monitoring that uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex. In contrast, conventional electroencephalography (EEG) electrodes monitor this activity from outside the skull. ECoG may be performed either in the operating room during surgery or outside of surgery. Because a craniotomy is required to implant the electrode grid, ECoG is an invasive procedure.
Neuro-oncology is the study of brain and spinal cord neoplasms, many of which are very dangerous and life-threatening. Among the malignant brain cancers, gliomas of the brainstem and pons, glioblastoma multiforme, and high-grade astrocytoma/oligodendroglioma are among the worst. In these cases, untreated survival usually amounts to only a few months, and survival with current radiation and chemotherapy treatments may extend that time from around a year to a year and a half, possibly two or more, depending on the patient's condition, immune function, treatments used, and the specific type of malignant brain neoplasm. Surgery may in some cases be curative, but, as a general rule, malignant brain cancers tend to regenerate and emerge from remission easily, especially highly malignant cases. In such cases, the goal is to excise as much of the mass and as much of the tumor margin as possible without endangering vital functions or other important cognitive abilities. The Journal of Neuro-Oncology is the longest continuously published journal in the field and serves as a leading reference to those practicing in the area of neuro-oncology.
Cortical stimulation mapping (CSM) is a type of electrocorticography that involves a physically invasive procedure and aims to localize the function of specific brain regions through direct electrical stimulation of the cerebral cortex. It remains one of the earliest methods of analyzing the brain and has allowed researchers to study the relationship between cortical structure and systemic function. Cortical stimulation mapping is used for a number of clinical and therapeutic applications, and remains the preferred method for the pre-surgical mapping of the motor cortex and language areas to prevent unnecessary functional damage. There are also some clinical applications for cortical stimulation mapping, such as the treatment of epilepsy.
Aaron A. Cohen-Gadol is a professor of clinical neurological surgery at the Keck School of Medicine of USC.
Intraoperative magnetic resonance imaging (iMRI) is an operating room configuration that enables surgeons to image the patient via an MRI scanner while the patient is undergoing surgery, particularly brain surgery. iMRI reduces the risk of damaging critical parts of the brain and helps confirm that the surgery was successful or if additional resection is needed before the patient's head is closed and the surgery completed.
James Rutka is a Canadian neurosurgeon from Toronto, Canada. Rutka served as RS McLaughlin Professor and Chair of the Department of Surgery in the Faculty of Medicine at the University of Toronto from 2011 – 2022. He subspecializes in pediatric neurosurgery at The Hospital for Sick Children (SickKids), and is a Senior Scientist in the Research Institute at SickKids. His main clinical interests include the neurosurgical treatment of children with brain tumours and epilepsy. His research interests lie in the molecular biology of human brain tumours – specifically in the determination of the mechanisms by which brain tumours grow and invade. He is the Director of the Arthur and Sonia Labatt Brain Tumour Research Centre at SickKids, and Editor-in-Chief of the Journal of Neurosurgery.
Isabelle M. Germano is a neurosurgeon and professor of neurosurgery, neurology, and oncology at the Icahn School of Medicine at Mount Sinai Hospital. She is a Fellow of the American College of Surgeons and the American Association of Neurological Surgeons. Germano works with image-guided brain and spine surgery.
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Günther C. Feigl is an Austrian neurosurgeon. Feigl is an internationally renowned expert in minimally invasive neurosurgery. His main areas of expertise are skull base surgery and neurooncology. He specializes in the surgery of gliomas, minimally invasive endoscopy-assisted microvascular decompression in trigeminal neuralgia and facial hemispasm as well as the surgery of acoustic neuromas, tumors of the pineal gland and meningiomas of the skull base. Furthermore, his specialties comprise treatment of pituitary adenomas, spinal cord tumours and metastases as well as the area of pediatric neurosurgery.
Alex Bekker is a physician, author and academic. He is a professor and chair at the Department of Anesthesiology, Rutgers New Jersey Medical School. He is also professor at the Department of Physiology, Pharmacology & Neurosciences. He serves as the Chief of Anesthesiology Service at the University Hospital in Newark.
Henry Brem, M.D. is an American neurosurgeon, researcher, educator and inventor known for introducing an image guidance computer system to deliver targeted chemotherapy to intraoperative brain tumors. As of 2023, he is the Harvey Cushing Professor, Director of the Department of Neurosurgery, Professor of Neurosurgery, Ophthalmology, Oncology and Biomedical Engineering Neurosurgeon-in-Chief, and Director, Hunterian Neurosurgical Research Center and Director at Johns Hopkins in Baltimore, Maryland. Brem has written more than 490 peer-reviewed articles, 50 books and book chapters and holds 11 patents.