Selected chapters from neurosurgery

Surgical technique, basic procedures in neurosurgery

Authors: Marek Sova, Pavel Fadrus, Václav Vybíhal, Martin Smrčka

Surgical technique in neurosurgery has its specifics, which are based on the anatomical and physiological conditions of the nervous system. At the beginning of the operation, it is necessary to overcome its protective bony and fibrous sheaths, followed by its own interrelationship with the brain or spinal cord, and the end of the operation is devoted to reconstruction with a watertight closure of the original envelope of the nervous system. In addition to basic surgical procedures, most operations are performed using microsurgery. A necessary condition, in addition to mastering the microsurgical operating technique, is the need for adequate technical equipment in the operating room. Especially in neurooncology, a number of devices (neuronavigation, electrophysiological monitoring, perioperative imaging methods) are also used, which help to increase the radicality and safety of resection procedures.

The tutorial video covers the basic procedures in neurosurgery. At the beginning is an introduction to the issue of neurosurgery with an explanation of the specifics of the equipment in the neurosurgical operating room. Special attention is paid to the issue of positioning and fixation of the patient before neurosurgery. The video presentation includes a total of four instructional videos. The first of these shows the fixation of the patient's head to the Mayfield head clamp. The second video is devoted to the basic neurosurgical procedure, skull trephination, in this case with the finding of a chronic subdural hematoma. The third video documents the implantation of external ventricular drainage in obstructive hydrocephalus and the last video documents well the whole course of performing an osteoplastic craniotomy of the skull, in this case a patient with a traumatic acute subdural hemorrhage.

Chronic subdural hematoma – trephination (making a burr hole)

Authors: Václav Vybíhal, Pavel Fadrus, Marek Sova, Martin Smrčka

Chronic subdural hematoma is bleeding between the dura mater and the arachnoid. The subdural space is not visible under physiological circumstances. The source of bleeding is most often bridging veins, which can rupture even with minor trauma. It mainly affects patients with brain atrophy (elderly patients) and blood clotting disorders (eg warfarinized patients). Initially, a small clot is formed, which may not cause the patient any problems. On average in around 3-4 weeks, the first clinical problems appear, such as headaches, confusion, hemiparesis, etc. The reason is that the clot has dissolved, which, due to its high osmolality, absorbs water from the surrounding tissues and thus significantly increases the volume of pathological fluid in the subdural space. In these cases, it is necessary to remove the old bleeding. The principle of the operation is to perform a trephination (drilling) – drilling a hole of approximately 1 cm in the bone, cutting the dura and removing the hematoma using lavage. Drains are relatively often introduced into the subdural space to drain the remainder of the old bleeding after lavage. Compressed brain tissue develops gradually, but incipient improvement is often seen immediately after surgery.

The tutorial video covers trephination in chronic subdural hematoma. At the beginning there is an introduction to the issue and basic information about chronic subdural hematoma. It is bleeding between the dura mater and the arachnoid. The subdural space is not visible under physiological circumstances. The source of bleeding is most often bridging veins, which can rupture even with minor trauma. It mainly affects patients with brain atrophy (elderly patients) and blood clotting disorders (eg warfarinized patients). Initially, a small clot is formed, which may not cause the patient any problems. On average in around 3-4 weeks, the first clinical problems appear, such as headaches, confusion, hemiparesis, etc. The reason is that the clot has dissolved, which, due to its high osmolality, absorbs water from the surrounding tissues and thus significantly increases the volume of pathological fluid in the subdural space. In these cases, it is necessary to remove the old bleeding. The principle of the operation is to perform a trephination (drilling) – drilling a hole of approximately 1cm in the bone, cutting the dura and removing the hematoma using lavage. Drains are relatively often introduced into the subdural space to drain the remainder of the old bleeding after lavage. Compressed brain tissue develops gradually, but incipient improvement is often seen immediately after surgery. The whole operation is then captured on video.

Endoscopic third ventriculostomy (ETV)

Authors: Václav Vybíhal, Pavel Fadrus, Marek Sova, Martin Smrčka

Endoscopic third ventriculostomy (ETV) is an operation performed on patients with obstructive hydrocephalus. It is a mini-invasive method with a high success rate and minimal complications. The principle is to perform a stoma (opening) using an endoscope at the floor of the third ventricle in the area of the so-called tuber cinereum, which creates an alternative path of cerebrospinal fluid flow in the case of an obstruction in the ventricular system.

The tutorial video covers endoscopic third ventriculostomy. At the beginning there is an introduction to the issue and basic information explaining the following video about the operation, which is performed on patients with obstructive hydrocephalus. It is a mini-invasive method with a high success rate and minimal complications. The principle is to perform a stoma (opening) using an endoscope at the floor of the third ventricle in the area of the so-called tuber cinereum, which creates an alternative path of cerebrospinal fluid flow in the case of an obstruction in the ventricular system.

Supplementary tests in normal pressure hydrocephalus (NPH)

Authors: Václav Vybíhal, Pavel Fadrus, Marek Sova, Martin Smrčka

Normal pressure hydrocephalus is a specific form of communicating hydrocephalus, where dilatation of the ventricular system is accompanied by gait disturbance, dementia and sphincter problems at normal pressure during a lumbar puncture. All three symptoms occur in less than half of the patients. The main symptom is a gait disorder. Differential diagnosis is difficult because many diseases can have similar symptoms. Therefore, functional tests have been introduced into clinical practice, which are used in the diagnosis and prediction of the effect of possible shunt surgery. Three tests are most often used. The so-called tap test, ie lumbar puncture with removal of 30-50 ml of cerebrospinal fluid. If the clinical condition improves after the cerebrospinal fluid is removed, the patient is then indicated for surgery. Furthermore, there is the lumbar infusion test, which tests the ability to absorb cerebrospinal fluid. If an absorption disorder is demonstrated, the patient is then indicated for surgery. The third test is external lumbar drainage, in which the cerebrospinal fluid is drained for 3-5 days, and if the clinical condition improves, the patient is indicated for surgery. The tests can be used singly or in combination, for example, a lumbar infusion test and external lumbar drainage.

The tutorial video covers functional tests for normal pressure hydrocephalus. At the beginning is an introduction to the issue and basic information about normal pressure hydrocephalus. It is a specific form of communicating hydrocephalus, where dilatation of the ventricular system is accompanied by gait disturbance, dementia and sphincter problems at normal pressure during a lumbar puncture. All three symptoms occur in less than half of the patients. The main symptom is a gait disorder. Differential diagnosis is difficult because many diseases can have similar symptoms. Therefore, functional tests have been introduced into clinical practice, which are used in the diagnosis and prediction of the effect of possible shunt surgery. Three tests are most often used. The so-called tap test, ie lumbar puncture with removal of 30-50 ml of cerebrospinal fluid. If the clinical condition improves after the cerebrospinal fluid is removed, the patient is then indicated for surgery. Furthermore, there is the lumbar infusion test, which tests the ability to absorb cerebrospinal fluid. If an absorption disorder is demonstrated, the patient is then indicated for surgery. The third test is external lumbar drainage, in which the cerebrospinal fluid is drained for 3-5 days, and if the clinical condition improves, the patient is indicated for surgery. The tests can be used singly or in combination, for example, a lumbar infusion test and external lumbar drainage. These two tests are then captured on an instructional video.

Introduction of a ventriculoperitoneal shunt

Authors: Václav Vybíhal, Pavel Fadrus, Marek Sova, Martin Smrčka

Ventriculoperitoneal shunt implantation is an operation performed on patients with hydrocephalus. Although it is a universal procedure applicable to all types of hydrocephalus, it is mainly used for communicating (non-obstructive) hydrocephalus, because endoscopic treatment is preferred in patients with obstructive hydrocephalus. The principle is to insert a ventricular catheter into the ventricular system. It is then connected to a valve that regulates the flow of cerebrospinal fluid from the ventricles. It is most often placed behind the ear. A peritoneal catheter runs from the other end of the valve, which is inserted into the abdominal cavity, where the extra fluid is absorbed.

The tutorial video covers the implantation of a ventriculoperitoneal shunt. At the beginning there is an introduction to the issue and basic information explaining the following video about the operation, which is applicable to all types of hydrocephalus, but is used mainly in communicating (non-obstructive) hydrocephalus, because endoscopic treatment is preferred in patients with obstructive hydrocephalus. The principle is to insert a ventricular catheter into the ventricular system. It is then connected to a valve that regulates the flow of cerebrospinal fluid from the ventricles. It is most often placed behind the ear. A peritoneal catheter runs from the other end of the valve, which is inserted into the abdominal cavity, where the excess fluid is absorbed.

Transnasal extirpation of a pituitary adenoma

Authors: Václav Vybíhal, Karel Máca, Milan Vidlák, Pavel Fadrus, Martin Smrčka

The pituitary gland is located in the Turkish seat. It consists of two parts - anterior (adenohypophysis) and posterior (neurohypophysis). It connects to the hypothalamus using a pituitary stalk. Above the pituitary gland there is a crossing of the optic nerves (chiasma opticum). The hypothalamic-pituitary system produces a number of hormones that control the activity of other endocrine glands. The most common pituitary tumor is adenoma. Fortunately, the malignant variant, cancer, is rare. The symptoms of a tumor depend on whether the tumor is hormonally active (functional adenomas) or hormonally inactive (functional adenomas). Overproduction of individual hormones is manifested by typical symptoms, such as acromegaly, the overproduction of growth hormone in adults. Thus, relatively small tumors, referred to as microadenomas (up to 10 mm), can manifest themselves. In contrast, dysfunctional adenomas usually manifest clinically at a larger size and are referred to as macroadenomas (10 mm and larger). They may cause problems with pressure on the chiasma opticum, which results in the typical finding of visual impairment of bitemporal hemianopsia. Symptomatic tumors are indicated for surgery, ie with hormonal overproduction or causing visual difficulties, possibly touching visual structures. Due to the anatomical conditions and properties of the tumor (relatively fragile and soft tumor), a transnasal approach using an endoscope is used (an alternative is to use an operating microscope). The principle of the operation is the insertion of an endoscope into the nasal cavity, the removal of the anterior wall of the sphenoid cavity and, after penetrating into this cavity, the removal of the base of the Turkish seat. After the incision of the dura mater, the tumor tissue is then removed with the help of the appropriate tools. The dura mater defect is treated with a piece of fascia, which is sealed with tissue glue, and a temporary tamponade is introduced.

The tutorial video covers the transnasal extirpation of the pituitary adenoma. At the beginning there is an introduction to the issue and basic information explaining the following video about the operation. The pituitary gland is located in the Turkish seat. It consists of two parts - anterior (adenohypophysis) and posterior (neurohypophysis). It connects to the hypothalamus using a stalk. Above the pituitary gland there is a crossing of the optic nerves (chiasma opticum). The hypothalamic-pituitary system produces a number of hormones that control the activity of other endocrine glands.

Awake craniotomy – brain tumour surgery

Authors: Eduard Neuman, Marek Sova, Václav Vybíhal, Milena Košťálová, Kateřina Procházková, Andrea Doleželová, Pavel Fadrus, Martin Smrčka

Awake brain surgery is a type of surgery performed on the brain while the patient is conscious and alert. It is used to treat certain brain (neurological) diseases such as brain tumors or epilepsy. If the tumor is close to important centers, such as the speech or motor centers, the centers related to cognitive abilities or emotions, it is necessary for the patient to be awake during the procedure in order to have a good result.

The tutorial video concerns the so-called awake operation, an operation with an awake phase. At the beginning there is an introduction to the issue and basic information explaining the following video about the operation, which is performed on patients with certain types of tumors near functionally important centers. The principle is for the patient to be awake during the operation and to test the functions we want to maintain.

Subarachnoid hemorrhage from a cerebral aneurysm

Authors: Ondřej Navrátil, Karel Svoboda, Vilém Juráň, Martin Smrčka

Subarachnoid hemorrhage is a serious condition with relatively high mortality even today. The most common cause is rupture of an aneurysm. Its treatment within 72 hours plays a fundamental role in the therapy and its success. Treatment is possible surgically or endovascularly. The basis of surgical therapy is the so-called clipping, ie placing a clip on the aneurysm. It is also possible to treat the aneurysm endovascularly, by coiling (filling with spirals) or by inserting a stent, and in case of complicated situations by using a combination of both of these techniques.

The tutorial video is about performing aneurysm clipping. At the beginning is an introduction to the issue and basic information explaining the following video about the operation, which is performed on patients with rupture of an aneurysm. The principle is to place a clip on the aneurysm and take it out of the circulation. The effect of surgical therapy is permanent and there is no need for repeated examinations by imaging methods.

Pial arteriovenous malformations of the brain

Authors: Ondřej Navrátil, Karel Svoboda, Vilém Juráň, Martin Smrčka

A brain arteriovenous malformation (AVM) is a tangle of abnormal blood vessels connecting arteries and veins in the brain. Brain AVMs are rare and affect less than 1 percent of the population. Most people are born with them, but they can occasionally form later in life. Some people with brain AVMs experience signs and symptoms such as headache or seizures. AVMs are commonly found after a brain scan for another health issue or after the blood vessels rupture and cause bleeding in the brain (hemorrhage). AVMs are usually diagnosed through a combination of magnetic resonance imaging (MRI) and angiography. The management options for brain AVMs (ruptured or un-ruptured) include observation or various treatment techniques such as microsurgical techniques, endovascular embolization and stereotactic radiotherapy used alone or as a combination.

The tutorial video covers the surgical treatment of arteriovenous malformations. At the beginning is an introduction to the issue and basic information explaining the following video about the operation, which is performed on patients with AVM. The principle is to remove the AVM using a craniotomy. It is first necessary to look for the supplying arteries, gradually resect the nidus and, lastly, treat the venous drainage.

Link		Date	Availability [?]	Clinically sensitive [?]	Licence
Surgical technique, basic procedures in neurosurgery		10.2.2021	MEFANET user	–
Chronic subdural hematoma – trephination (making a burr hole)		10.2.2021	MEFANET user	–
Endoscopic third ventriculostomy (ETV)		10.2.2021	MEFANET user	–
Supplementary tests in normal pressure hydrocephalus (NPH)		10.2.2021	MEFANET user	–
Introduction of a ventriculoperitoneal shunt		10.2.2021	MEFANET user	–
Transnasal extirpation of a pituitary adenoma		10.2.2021	MEFANET user	–
Awake craniotomy – brain tumour surgery		10.2.2021	MEFANET user	–
Subarachnoid hemorrhage from a cerebral aneurysm		10.2.2021	MEFANET user	–
Pial arteriovenous malformations of the brain		10.2.2021	MEFANET user	–

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