This document describes the operative approaches for removing tumors in the fourth ventricle. It discusses the midline suboccipital approach as the safest and most direct method. It covers important preoperative considerations like imaging, antibiotics, and steroids. It also discusses important intraoperative monitoring techniques like brainstem auditory evoked potentials. Finally, it provides details on patient positioning including prone, lateral, and sitting positions as well as the risks and benefits of each position.
The document discusses various surgical approaches to the temporal bone, including:
1. The anterior, posterior, superior, and inferior boundaries of the temporal bone.
2. Ten triangles of the temporal bone - four in the cavernous sinus and six in the middle fossa.
3. The Kawase vs modified Dolenc-Kawase approach - which differs in the drilling sequence and angle of approach.
4. Several cranial fossa approaches - simple middle cranial fossa, anterior petrosectomy, extended middle fossa, presigmoid, and various modifications.
5. Anatomic landmarks and surgical techniques for the postauricular transtemporal, combined presigmoid
The document describes the anatomy and relationships of the tentorium cerebelli. It is a extension of dura that separates the occipital lobes from the cerebellum. It forms the anterior, middle, and posterior incisural spaces which contain neural, vascular, and cerebrospinal fluid structures. The anterior incisural space contains parts of the circle of Willis and optic structures. The middle incisural space contains cranial nerves 4 and 5 and relates to the temporal horn. The posterior incisural space contains the vein of Galen and quadrigeminal cistern. Herniation can occur through these spaces which can compress surrounding structures.
The document provides details about the pterional craniotomy procedure, including:
- The pterional craniotomy allows exposure of the frontal, temporal, and parietal bones and provides access to lesions in the anterior circulation.
- Key steps include patient positioning with 30-60 degree head rotation, a curvilinear scalp incision, temporalis muscle dissection, three burr holes with craniotomy, sphenoid bone drilling, dura opening, and Sylvian fissure dissection.
- Closure involves checking for bleeding, dural closure, bone flap replacement, and layered soft tissue closure. Limitations include exposure limitations depending on lesion size and location.
1) The skull base surgery approaches discussed allow surgeons to access different regions of the skull base to treat lesions while avoiding harm to intact structures.
2) Key approaches described include the pterional, frontolateral, transsphenoidal, suboccipital lateral, and various transpetrous approaches.
3) Endoscopic skull base surgery has advanced to allow minimally invasive access to regions from the cribriform plate to the foramen magnum and laterally to the infratemporal fossa.
This document provides an overview of normal variants and anatomy of the intracranial arteries, beginning with abbreviations used. It then describes the gross anatomy and specific segments of the internal carotid, basilar, vertebral, and posterior cerebral arteries. Vascular territories supplied by each artery are outlined. Finally, the document discusses normal variants and anomalies that can occur in the internal carotid artery anatomy. In particular, it notes that fenestration of the distal internal carotid artery is a rare finding associated with aneurysm formation. It also describes hyperplastic anterior choroidal arteries as a normal variant where the artery is enlarged beyond typical size.
This document provides a detailed anatomical description of the structures that make up the fourth ventricle. It describes the roof, floor, and lateral recesses of the fourth ventricle. The roof is divided into an upper and lower portion. The upper portion includes the superior medullary velum and is related to the cerebellomesencephalic fissure. The lower portion includes the inferior medullary velum, nodule, and tela choroidea and is related to the cerebellomedullary fissure. The lateral recesses open into the cerebellopontine angles. The floor is divided into three parts. The document provides a comprehensive overview of the microsurgical anatomy of
The document describes the frontotemporal orbitozygomatic (FTOZ) craniotomy surgical approach. It discusses the key anatomical landmarks and surgical steps involved in the approach. The FTOZ approach provides exposure of the parasellar region, anterior circulation aneurysms, and lesions of the cavernous sinus. It can be performed as a one-piece, two-piece, or three-piece craniotomy. Important tips include protecting the superficial temporal artery and periorbita during dissection and osteotomies.
The document discusses various surgical approaches to the temporal bone, including:
1. The anterior, posterior, superior, and inferior boundaries of the temporal bone.
2. Ten triangles of the temporal bone - four in the cavernous sinus and six in the middle fossa.
3. The Kawase vs modified Dolenc-Kawase approach - which differs in the drilling sequence and angle of approach.
4. Several cranial fossa approaches - simple middle cranial fossa, anterior petrosectomy, extended middle fossa, presigmoid, and various modifications.
5. Anatomic landmarks and surgical techniques for the postauricular transtemporal, combined presigmoid
The document describes the anatomy and relationships of the tentorium cerebelli. It is a extension of dura that separates the occipital lobes from the cerebellum. It forms the anterior, middle, and posterior incisural spaces which contain neural, vascular, and cerebrospinal fluid structures. The anterior incisural space contains parts of the circle of Willis and optic structures. The middle incisural space contains cranial nerves 4 and 5 and relates to the temporal horn. The posterior incisural space contains the vein of Galen and quadrigeminal cistern. Herniation can occur through these spaces which can compress surrounding structures.
The document provides details about the pterional craniotomy procedure, including:
- The pterional craniotomy allows exposure of the frontal, temporal, and parietal bones and provides access to lesions in the anterior circulation.
- Key steps include patient positioning with 30-60 degree head rotation, a curvilinear scalp incision, temporalis muscle dissection, three burr holes with craniotomy, sphenoid bone drilling, dura opening, and Sylvian fissure dissection.
- Closure involves checking for bleeding, dural closure, bone flap replacement, and layered soft tissue closure. Limitations include exposure limitations depending on lesion size and location.
1) The skull base surgery approaches discussed allow surgeons to access different regions of the skull base to treat lesions while avoiding harm to intact structures.
2) Key approaches described include the pterional, frontolateral, transsphenoidal, suboccipital lateral, and various transpetrous approaches.
3) Endoscopic skull base surgery has advanced to allow minimally invasive access to regions from the cribriform plate to the foramen magnum and laterally to the infratemporal fossa.
This document provides an overview of normal variants and anatomy of the intracranial arteries, beginning with abbreviations used. It then describes the gross anatomy and specific segments of the internal carotid, basilar, vertebral, and posterior cerebral arteries. Vascular territories supplied by each artery are outlined. Finally, the document discusses normal variants and anomalies that can occur in the internal carotid artery anatomy. In particular, it notes that fenestration of the distal internal carotid artery is a rare finding associated with aneurysm formation. It also describes hyperplastic anterior choroidal arteries as a normal variant where the artery is enlarged beyond typical size.
This document provides a detailed anatomical description of the structures that make up the fourth ventricle. It describes the roof, floor, and lateral recesses of the fourth ventricle. The roof is divided into an upper and lower portion. The upper portion includes the superior medullary velum and is related to the cerebellomesencephalic fissure. The lower portion includes the inferior medullary velum, nodule, and tela choroidea and is related to the cerebellomedullary fissure. The lateral recesses open into the cerebellopontine angles. The floor is divided into three parts. The document provides a comprehensive overview of the microsurgical anatomy of
The document describes the frontotemporal orbitozygomatic (FTOZ) craniotomy surgical approach. It discusses the key anatomical landmarks and surgical steps involved in the approach. The FTOZ approach provides exposure of the parasellar region, anterior circulation aneurysms, and lesions of the cavernous sinus. It can be performed as a one-piece, two-piece, or three-piece craniotomy. Important tips include protecting the superficial temporal artery and periorbita during dissection and osteotomies.
This document discusses the anatomy of the skull base. It begins by explaining that the skull base develops primarily from cartilage precursors and forms the floor of the cranial cavity. It then describes the development of the various cartilage components that fuse together to form bones of the skull base, including the parachordal, sclerotomal, hypophyseal, presphenoid, orbitosphenoid, and alisphenoid cartilages. The document further details the boundaries and structures of the anterior, middle, and posterior skull base, emphasizing the role of the sphenoid bone in forming the central skull base. Key anatomical landmarks and contents of the cavernous sinus, optic canal, and superior orbital fiss
Jugular foramen anatomy and approachesDikpal Singh
The jugular foramen is located at the skull base and formed by bones of the temporal and occipital bones. It contains nerves IX-XI and often the inferior petrosal sinus. Approaches to access the jugular foramen include posterior, lateral, and anterior. The posterior approach uses a suboccipital retrosigmoid, transcondylar, or supracondylar route. Lateral approaches are juxtacondylar or lateral skull base. Anterior approaches use a postauricular transtemporal or preauricular subtemporal route. Surgical techniques aim to expose the jugular foramen while preserving nearby structures like cranial nerves and vessels.
The document discusses the venous anatomy of the brain. It describes the superficial and deep venous systems that drain the brain. The superficial system includes four drainage groups - the superior sagittal, sphenoidal, tentorial, and falcine groups. These groups drain into dural sinuses. The deep system includes ventricular veins that drain the lateral ventricles and cisternal veins that drain the basal cisterns. Key veins discussed include the internal cerebral veins, great vein, basal vein, and veins within the posterior fossa. Understanding the venous anatomy is important for surgical planning and radiological localization of lesions.
MRI and CT cross sectional anatomy and sulci gyri anatomy of brain.ppt pdfDr pradeep Kumar
This ppt is very important for radiology resident..Nice sectional anatomy of brain MRI as well as CT. Axial, saggital and coronal section of human brain .This presentation also include very good sectional anatomy of sulci and gyri of brain with labelling of all images . Must know for radiologist. Thanks.
Skull base anatomy by Dr. Aditya TiwariAditya Tiwari
The document discusses the anatomy and embryology of the skull base. It describes the various bones that make up the skull base, including the sphenoid, occipital and temporal bones. It outlines the boundaries and contents of the different cranial fossae: anterior, middle, and posterior. It also details important anatomical structures in the skull base like the cavernous sinus, foramina, and various nerves and vessels that pass through the skull base. Comprehensive knowledge of the skull base anatomy is important for understanding pathologies and surgical planning.
This document describes various craniometric points and landmarks that are used as references in neurosurgery. It defines points such as the pterion, asterion, euryon, stephanion, vertex, nasion, inion, glabella, bregma, lambda, and others. It explains the location and anatomical relationships of each point. It also discusses how some craniometric points are used to localize structures like the ventricles, cortical areas such as the motor cortex, venous structures, and for strategically placing burr holes during craniotomies. Understanding the location of these points is important for surgical planning and navigation.
Before embarking on an approach, the surgeon should be familiar with both the ventricular anatomy and the options for optimally Accessing lesions in third ventricle is a surgical challenge because of its difficult corridor as well as deeper location, need of neural incision, preservation of vascular, thalamus and hypothalamus and likely risk of fornix injury.
This document summarizes the venous drainage of the brain. It describes the major dural venous sinuses, including the superior group composed of the straight, sagittal, and transverse sinuses and the basal group including the cavernous, petrosal, and sphenoparietal sinuses. It also details the cerebral veins including the superficial veins that drain to the cavernous sinus and deep veins like the basal veins of Rosenthal and internal cerebral vein that drain to the vein of Galen and straight sinus. Finally, it discusses the posterior fossa veins like the anterior and posterior pontomesencephalic veins.
Posterior fossa contains vital structures including cerebellum and brain stem and Vertebrobasilar vascular tree. Posterior fossa is supplied by AICA, PICA, SCA and PCA and their branches.
This document discusses agenesis of the corpus callosum (ACC), which is a condition where the corpus callosum is partially or completely absent from birth. It provides details on the anatomy and development of the corpus callosum, ultrasound findings of ACC, clinical presentation, causes, treatment and prognosis. ACC can occur as an isolated birth defect or be associated with other brain or body abnormalities. The prognosis depends on whether additional abnormalities are present, with isolated ACC having a better prognosis than complex ACC involving other brain disorders.
The internal carotid artery arises from the common carotid artery and travels upward through the neck and into the skull. It has seven segments from C1-C7 as it passes through the carotid canal, cavernous sinus, and terminates by joining the circle of Willis. The internal carotid artery has few branches in the neck but gives off important branches in the cavernous sinus and within the skull such as the ophthalmic artery. Anatomical variations and injuries to the internal carotid artery during surgery can lead to serious complications if not properly managed.
The third ventricle is a midline cavity located between the two thalami and hypothalami. It communicates with the lateral ventricles via the foramen of Monroe and with the fourth ventricle via the cerebral aqueduct. The third ventricle's roof is formed by the fornix and tela choroidea, while its floor extends from the optic chiasm to the posterior perforated substance. The third ventricle can be accessed surgically through various anterior or posterior approaches between brain structures such as the fornix.
Brain vascular anatomy with MRA and MRI correlationArif S
This document provides an overview of the vascular anatomy of the brain. It discusses the arterial supply, venous drainage, and dural venous sinuses of the brain. For arterial supply, it describes the anterior and posterior circulations, including the internal carotid, vertebral, basilar, anterior cerebral, middle cerebral, and posterior cerebral arteries. It also discusses branches and territories of these vessels. For venous drainage, it outlines the internal cerebral veins and external cerebral veins, as well as dural venous sinuses such as the superior sagittal sinus. Watershed zones and vascular territories on cross sections are also depicted.
Liliequist membrane may be understood as a projection formed by an arachnoid membrane extending from the dorsum sellae to the mammillary bodies coined after Liliequist (1956). It has surgical importance in Endoscopic third ventriculostomy and cisternostomy.
This document discusses the anatomy of the sellar region. It describes the structures below and above the sella turcica such as the nasal cavity, sphenoid bone, pituitary fossa, and suprasellar region. It details the pituitary gland, diaphragma sellae, intercavernous connections, and the ventricular and arterial relationships above the sella. The sphenoid sinus, carotid prominences, and lateral wall are also examined. Neurovascular structures like the optic chiasm, oculomotor nerve, arteries, and veins are mapped in relation to the sellar region.
Brain stem surgical anatomy and approachesKode Sashanka
This document discusses the surgical anatomy and safe entry zones of the brain stem for tumor removal. It describes the anatomy of the midbrain, pons, and medulla oblongata. Several safe entry zones are outlined for each region, including the anterior mesencephalic zone and intercollicular region for the midbrain, the peritrigeminal and supratrigeminal zones for the pons, and the anterolateral sulcus and posterior median sulcus for the medulla. The document also reviews important tenets of brainstem surgery, such as using the two-point method, lighted bipolar cautery, autolock systems, and careful preservation of venous anatomy.
Sch 43 surgical management of tumors of the foramen magnum Neurosurgery Vajira
This document discusses the surgical management of tumors located in the foramen magnum. It begins by describing the anatomy of the foramen magnum and then discusses the classification, clinical presentation, imaging, and surgical approaches for tumors in this region. Specifically, it focuses on the far lateral approach, outlining the positioning, incisions, exposure of the vertebral artery, bone removal, dural opening, and tumor resection steps involved in this approach. Postoperative measures like monitoring for lower cranial nerve deficits are also mentioned.
Posterior Cranial Fossa with Cranial Nerves Relationnoorulain89
The posterior cranial fossa contains the brainstem and cerebellum. It houses the cerebellum, medulla, and pons. It receives 11 of the 12 cranial nerves, excluding the olfactory nerve. The cranial nerve nuclei are arranged with efferent nuclei medially and sensory nuclei laterally. From medial to lateral the general arrangement is: general somatic efferent, special visceral efferent, general visceral efferent, general visceral afferent, special visceral afferent, general sensory afferent, and special somatic afferent nuclei. The document provides details on the specific cranial nerves and nuclei in the brainstem.
This document discusses neuro-otological aspects of cerebellopontine angle tumors. It begins by describing the anatomy of the cerebellopontine angle and internal acoustic meatus. It then covers the neurophysiology of hearing and vestibular function, as well as common cerebellopontine angle masses like vestibular schwannoma. The clinical presentation, investigations including tuning fork tests, caloric testing, and imaging are discussed. Specific tests like Rinne's test and auditory brainstem response are also summarized.
This document discusses various patient positions used during surgery and their implications for anesthesia. It describes positions like supine, prone, beach chair, lateral, lithotomy, Trendelenburg, and reverse Trendelenburg. For each position, it discusses the effects on ventilation, hemodynamics, and risks of complications like nerve injuries or pressure sores. It emphasizes the importance of the anesthesiologist considering factors like airway management, monitoring, line placement, and padding areas at risk of pressure when positioning patients for surgery.
This document discusses the anatomy of the skull base. It begins by explaining that the skull base develops primarily from cartilage precursors and forms the floor of the cranial cavity. It then describes the development of the various cartilage components that fuse together to form bones of the skull base, including the parachordal, sclerotomal, hypophyseal, presphenoid, orbitosphenoid, and alisphenoid cartilages. The document further details the boundaries and structures of the anterior, middle, and posterior skull base, emphasizing the role of the sphenoid bone in forming the central skull base. Key anatomical landmarks and contents of the cavernous sinus, optic canal, and superior orbital fiss
Jugular foramen anatomy and approachesDikpal Singh
The jugular foramen is located at the skull base and formed by bones of the temporal and occipital bones. It contains nerves IX-XI and often the inferior petrosal sinus. Approaches to access the jugular foramen include posterior, lateral, and anterior. The posterior approach uses a suboccipital retrosigmoid, transcondylar, or supracondylar route. Lateral approaches are juxtacondylar or lateral skull base. Anterior approaches use a postauricular transtemporal or preauricular subtemporal route. Surgical techniques aim to expose the jugular foramen while preserving nearby structures like cranial nerves and vessels.
The document discusses the venous anatomy of the brain. It describes the superficial and deep venous systems that drain the brain. The superficial system includes four drainage groups - the superior sagittal, sphenoidal, tentorial, and falcine groups. These groups drain into dural sinuses. The deep system includes ventricular veins that drain the lateral ventricles and cisternal veins that drain the basal cisterns. Key veins discussed include the internal cerebral veins, great vein, basal vein, and veins within the posterior fossa. Understanding the venous anatomy is important for surgical planning and radiological localization of lesions.
MRI and CT cross sectional anatomy and sulci gyri anatomy of brain.ppt pdfDr pradeep Kumar
This ppt is very important for radiology resident..Nice sectional anatomy of brain MRI as well as CT. Axial, saggital and coronal section of human brain .This presentation also include very good sectional anatomy of sulci and gyri of brain with labelling of all images . Must know for radiologist. Thanks.
Skull base anatomy by Dr. Aditya TiwariAditya Tiwari
The document discusses the anatomy and embryology of the skull base. It describes the various bones that make up the skull base, including the sphenoid, occipital and temporal bones. It outlines the boundaries and contents of the different cranial fossae: anterior, middle, and posterior. It also details important anatomical structures in the skull base like the cavernous sinus, foramina, and various nerves and vessels that pass through the skull base. Comprehensive knowledge of the skull base anatomy is important for understanding pathologies and surgical planning.
This document describes various craniometric points and landmarks that are used as references in neurosurgery. It defines points such as the pterion, asterion, euryon, stephanion, vertex, nasion, inion, glabella, bregma, lambda, and others. It explains the location and anatomical relationships of each point. It also discusses how some craniometric points are used to localize structures like the ventricles, cortical areas such as the motor cortex, venous structures, and for strategically placing burr holes during craniotomies. Understanding the location of these points is important for surgical planning and navigation.
Before embarking on an approach, the surgeon should be familiar with both the ventricular anatomy and the options for optimally Accessing lesions in third ventricle is a surgical challenge because of its difficult corridor as well as deeper location, need of neural incision, preservation of vascular, thalamus and hypothalamus and likely risk of fornix injury.
This document summarizes the venous drainage of the brain. It describes the major dural venous sinuses, including the superior group composed of the straight, sagittal, and transverse sinuses and the basal group including the cavernous, petrosal, and sphenoparietal sinuses. It also details the cerebral veins including the superficial veins that drain to the cavernous sinus and deep veins like the basal veins of Rosenthal and internal cerebral vein that drain to the vein of Galen and straight sinus. Finally, it discusses the posterior fossa veins like the anterior and posterior pontomesencephalic veins.
Posterior fossa contains vital structures including cerebellum and brain stem and Vertebrobasilar vascular tree. Posterior fossa is supplied by AICA, PICA, SCA and PCA and their branches.
This document discusses agenesis of the corpus callosum (ACC), which is a condition where the corpus callosum is partially or completely absent from birth. It provides details on the anatomy and development of the corpus callosum, ultrasound findings of ACC, clinical presentation, causes, treatment and prognosis. ACC can occur as an isolated birth defect or be associated with other brain or body abnormalities. The prognosis depends on whether additional abnormalities are present, with isolated ACC having a better prognosis than complex ACC involving other brain disorders.
The internal carotid artery arises from the common carotid artery and travels upward through the neck and into the skull. It has seven segments from C1-C7 as it passes through the carotid canal, cavernous sinus, and terminates by joining the circle of Willis. The internal carotid artery has few branches in the neck but gives off important branches in the cavernous sinus and within the skull such as the ophthalmic artery. Anatomical variations and injuries to the internal carotid artery during surgery can lead to serious complications if not properly managed.
The third ventricle is a midline cavity located between the two thalami and hypothalami. It communicates with the lateral ventricles via the foramen of Monroe and with the fourth ventricle via the cerebral aqueduct. The third ventricle's roof is formed by the fornix and tela choroidea, while its floor extends from the optic chiasm to the posterior perforated substance. The third ventricle can be accessed surgically through various anterior or posterior approaches between brain structures such as the fornix.
Brain vascular anatomy with MRA and MRI correlationArif S
This document provides an overview of the vascular anatomy of the brain. It discusses the arterial supply, venous drainage, and dural venous sinuses of the brain. For arterial supply, it describes the anterior and posterior circulations, including the internal carotid, vertebral, basilar, anterior cerebral, middle cerebral, and posterior cerebral arteries. It also discusses branches and territories of these vessels. For venous drainage, it outlines the internal cerebral veins and external cerebral veins, as well as dural venous sinuses such as the superior sagittal sinus. Watershed zones and vascular territories on cross sections are also depicted.
Liliequist membrane may be understood as a projection formed by an arachnoid membrane extending from the dorsum sellae to the mammillary bodies coined after Liliequist (1956). It has surgical importance in Endoscopic third ventriculostomy and cisternostomy.
This document discusses the anatomy of the sellar region. It describes the structures below and above the sella turcica such as the nasal cavity, sphenoid bone, pituitary fossa, and suprasellar region. It details the pituitary gland, diaphragma sellae, intercavernous connections, and the ventricular and arterial relationships above the sella. The sphenoid sinus, carotid prominences, and lateral wall are also examined. Neurovascular structures like the optic chiasm, oculomotor nerve, arteries, and veins are mapped in relation to the sellar region.
Brain stem surgical anatomy and approachesKode Sashanka
This document discusses the surgical anatomy and safe entry zones of the brain stem for tumor removal. It describes the anatomy of the midbrain, pons, and medulla oblongata. Several safe entry zones are outlined for each region, including the anterior mesencephalic zone and intercollicular region for the midbrain, the peritrigeminal and supratrigeminal zones for the pons, and the anterolateral sulcus and posterior median sulcus for the medulla. The document also reviews important tenets of brainstem surgery, such as using the two-point method, lighted bipolar cautery, autolock systems, and careful preservation of venous anatomy.
Sch 43 surgical management of tumors of the foramen magnum Neurosurgery Vajira
This document discusses the surgical management of tumors located in the foramen magnum. It begins by describing the anatomy of the foramen magnum and then discusses the classification, clinical presentation, imaging, and surgical approaches for tumors in this region. Specifically, it focuses on the far lateral approach, outlining the positioning, incisions, exposure of the vertebral artery, bone removal, dural opening, and tumor resection steps involved in this approach. Postoperative measures like monitoring for lower cranial nerve deficits are also mentioned.
Posterior Cranial Fossa with Cranial Nerves Relationnoorulain89
The posterior cranial fossa contains the brainstem and cerebellum. It houses the cerebellum, medulla, and pons. It receives 11 of the 12 cranial nerves, excluding the olfactory nerve. The cranial nerve nuclei are arranged with efferent nuclei medially and sensory nuclei laterally. From medial to lateral the general arrangement is: general somatic efferent, special visceral efferent, general visceral efferent, general visceral afferent, special visceral afferent, general sensory afferent, and special somatic afferent nuclei. The document provides details on the specific cranial nerves and nuclei in the brainstem.
This document discusses neuro-otological aspects of cerebellopontine angle tumors. It begins by describing the anatomy of the cerebellopontine angle and internal acoustic meatus. It then covers the neurophysiology of hearing and vestibular function, as well as common cerebellopontine angle masses like vestibular schwannoma. The clinical presentation, investigations including tuning fork tests, caloric testing, and imaging are discussed. Specific tests like Rinne's test and auditory brainstem response are also summarized.
This document discusses various patient positions used during surgery and their implications for anesthesia. It describes positions like supine, prone, beach chair, lateral, lithotomy, Trendelenburg, and reverse Trendelenburg. For each position, it discusses the effects on ventilation, hemodynamics, and risks of complications like nerve injuries or pressure sores. It emphasizes the importance of the anesthesiologist considering factors like airway management, monitoring, line placement, and padding areas at risk of pressure when positioning patients for surgery.
patient positioning in operative room.pptxmohsinyeshar
Lecture about tips and tricks for proper patient positioning in operative room
Description of common positions
Possible complications
And how to prevent complications
According to recent guidelines and references
This document discusses various positioning considerations for cranial surgery. It outlines different positions used including supine, lateral, prone, sitting, and variations. Key factors in positioning include access, comfort, safety, and reducing complications. Positions are chosen based on the surgical site and individual patient factors. Proper positioning is important to optimize exposure and outcomes while preventing pressure injuries and neurological complications.
This document discusses patient positioning for various spinal surgeries. It covers the equipment used including tables and head holders. The principles of positioning focus on surgical access, patient safety, spinal alignment, and surgeon ergonomics. Specific risks like neuropathies are reviewed along with how to position for different procedures such as anterior cervical, posterior thoracolumbar fusion, and lateral lumbar approaches. Intraoperative repositioning from prone to supine is also addressed.
This document provides information on maxillofacial trauma and its anaesthetic management. It begins with the relevant anatomy of the maxilla and important structures that can be damaged. It then describes Le Fort fracture patterns and their clinical features. Imaging studies like CT scans are the standard for evaluation. Special considerations for anaesthesia include securing the airway, which can be difficult due to the injuries, and managing blood loss. Various airway techniques are discussed like fiberoptic intubation, retrograde intubation, or surgical airways if needed. Intraoperative management focuses on invasive monitoring, induced hypotension to reduce bleeding, and muscle relaxation.
Acute management and decision making in spinal cord injury by dr ss sharmadrshyamsundersharma
These slides made by references of spinal cord medicine books for information,education and communication of physicians,paramedics and peoples by which early appropriate, accessible measures can be taken for mandatory spine cord injury care and management.
Anterior-o-lateral approach to thoraco lumbar regionZeeshan Nasir
1) The anterior-lateral approach to the thoracolumbar region provides wide exposure of the vertebral column and is used for pathologies like trauma, degenerative disc disease, tumors, infections, and deformities.
2) The surgical technique involves making an incision along the superior margin of the 10th or 12th rib and dissecting the rib from its muscle attachments to access the pleural cavity or retroperitoneal space.
3) During the procedure, segmental vessels are cauterized and the artery of Adamkiewicz is identified to avoid paraplegia if injured. Injury to the cisterna chyli can also lead to lymphocele or chyl
The subtemporal approach provides access to lesions of the middle fossa floor, anterior basal cisterns, upper clivus, and lateral thalamic regions. It involves a subtemporal craniotomy just above the zygomatic root to access the middle fossa floor. The temporal lobe is retracted extradurally or intradurally after identifying the vein of Labbe. Indications include temporal lobe tumors, midbrain tumors, and skull base lesions such as meningiomas. Care must be taken to preserve venous structures like the vein of Labbe to avoid temporal lobe infarction.
Dacrocystography and sialography are radiographic examinations of the lacrimal drainage system and salivary glands, respectively. Contrast medium is injected to outline the anatomy. Dacrocystography evaluates the lacrimal sac and nasolacrimal duct for obstructions, while sialography assesses the salivary glands and ducts for stones, strictures, or masses. Both procedures involve cannulating ducts, injecting low-volume contrast medium under fluoroscopy, and obtaining radiographs to identify any abnormalities. Potential complications are minor and include pain, contrast extravasation, or duct damage. Ultrasonography is now often used initially before resorting to invasive contrast studies
This document discusses optimal patient positioning for neurosurgery. It describes various positions used including supine, prone, lateral, and sitting. Sitting position provides good access but carries risks like hypotension, venous pooling, air embolism, pneumocephalus, and nerve injuries. Careful patient selection and technique are important to prevent complications. The roles of the anesthesiologist and surgeon in ensuring safe and effective positioning are emphasized.
Hypospadias is a congenital defect where the opening of the urethra is on the ventral side of the penis rather than at the tip. It occurs in about 1 in 250 male newborns and is thought to result from arrested penile development leaving a proximal urethral opening. Treatment involves surgical repair to reposition the urethra, which depends on the location and severity of the hypospadias but generally aims to maximize function and cosmetic appearance. Complications can include bleeding, meatal stenosis and fistula formation.
1. An intercostal drain, or chest tube, is a flexible plastic tube inserted through the chest wall to drain fluid or air from the pleural space. It works using an underwater seal mechanism that allows drainage out while preventing fluid or air from entering.
2. Chest tube insertion involves local anesthesia, positioning the patient, and using sterile technique to insert the tube through the chest wall into the pleural space. Ultrasound is used to guide placement and ensure the tube does not injure organs.
3. Physiotherapy for a patient with a chest tube focuses on wound care, pain management, deep breathing exercises, early mobilization, and exercise to improve ventilation and recovery.
Hypospadias is a congenital anomaly where the opening of the urethra is on the ventral side of the penis rather than at the tip. It occurs in about 1 in 250 male newborns. The document discusses the definition, causes, classification, diagnosis, and surgical techniques for repairing hypospadias. Surgical repair aims to correct penile curvature if present and create a functional urethra in a cosmetically normal position. Complications can include bleeding, meatal stenosis, and impaired healing but early repair from ages 6-12 months has better outcomes.
posterior cranial fossa surgery and anaesthesiaNARENDRA PATIL
This document discusses the anatomy of the posterior cranial fossa and common pathologies that require surgery in this area. It covers the clinical presentation of posterior fossa diseases and considerations for anesthetic management of posterior fossa surgeries. Key topics include patient positioning, intraoperative monitoring, complications like venous air embolism, and special considerations for pediatric patients. The goal of anesthetic management is to avoid increases in intracranial pressure while maintaining cardiovascular stability during surgery.
Orbital hypertelorism- Dr Narendra Uttamrao Markad, DNB Plastic SurgeryNarendra Markad
Orbital hypertelorism is an abnormal increase in the distance between the orbits. It can be caused by various craniofacial conditions and occurs when the orbits fail to move medially during development. Evaluation involves imaging and examination to plan surgery. The goals of surgery are to narrow the interorbital distance and nasal bones. Approaches include box osteotomy, which mobilizes the orbits medially, and facial bipartition, which separates the midface. Careful planning and postoperative monitoring are needed to address this complex deformity and achieve the best outcomes.
This document discusses anaesthetic considerations for posterior fossa surgery. The posterior fossa is a rigid compartment containing important structures like the brainstem and cerebellum. Tumours are a common pathology requiring posterior fossa surgery. Different surgical positions like sitting and park bench are used but come with challenges and risks for anaesthetists, including venous air embolism in the sitting position. Careful patient evaluation, monitoring, maintenance of haemodynamic stability and early detection of complications are important aspects of anaesthetic management for posterior fossa surgery.
This document provides an overview of the anterior approach to the shoulder, also known as the deltopectoral approach. It indicates the approach gives access to the anterior, medial, and lateral aspects of the shoulder and can extend distally to include the anterior humerus. Common indications for the approach include shoulder arthroplasty, proximal humerus fractures, recurrent dislocation reconstruction, and biceps or tumor procedures. The document describes relevant anatomy, patient positioning, landmarks, surgical steps including incision, exposure, and potential dangers like nerve injury.
This document discusses various patient positioning techniques used in neurosurgery and their principles and potential complications. It describes the supine, lateral, prone, three-quarter prone, and sitting positions. For each position, it outlines how the patient should be positioned on the operating table, how the head can be fixed, advantages and limitations, and examples of procedures it can be used for. It notes that correctly positioning the patient is important for patient safety, surgeon comfort, optimal surgical access, and reducing brain tension. Complications can occur if proper positioning guidelines are not followed.
Incisions and position in general surgery by dr chandrakant sabaleCHANDRAKANT SABALE
This document discusses surgical incisions and patient positioning in general surgery. It provides details on:
1. Types of incisions like vertical, transverse, oblique and their uses in different abdominal and pelvic surgeries.
2. Principles of incision placement and closure.
3. Langer's lines and their importance in wound healing.
4. Common patient positions used in surgery like supine, lateral, lithotomy and their advantages.
Similar to Operative approaches for 4th ventricular tumours (20)
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
ABDOMINAL TRAUMA in pediatrics part one.drhasanrajab
Abdominal trauma in pediatrics refers to injuries or damage to the abdominal organs in children. It can occur due to various causes such as falls, motor vehicle accidents, sports-related injuries, and physical abuse. Children are more vulnerable to abdominal trauma due to their unique anatomical and physiological characteristics. Signs and symptoms include abdominal pain, tenderness, distension, vomiting, and signs of shock. Diagnosis involves physical examination, imaging studies, and laboratory tests. Management depends on the severity and may involve conservative treatment or surgical intervention. Prevention is crucial in reducing the incidence of abdominal trauma in children.
Here is the updated list of Top Best Ayurvedic medicine for Gas and Indigestion and those are Gas-O-Go Syp for Dyspepsia | Lavizyme Syrup for Acidity | Yumzyme Hepatoprotective Capsules etc
Top Effective Soaps for Fungal Skin Infections in India
Operative approaches for 4th ventricular tumours
1. Operative approaches for 4th
ventricular tumours
Dr. Paresh Kumar Gouda
FINAL YEAR RESIDENT
NEUROSURGERY
2. Fourth ventricle viewed from the side (A) and from
behind (B). Landmarks such as the vertical median sulcus and oblique
calamus scriptorius give the caudal floor the appearance of a fountain
pen. (Modified from Cohen AR. Surgical Disorders of the Fourth Ventricle.
Cambridge, MA: Blackwell Science; 1996.)
5. • The safest and most direct approach to the fourth
ventricle is the midline suboccipital approach.
• Preoperative:
• All imaging and labs should be reviewed carefully.
• Antibiotics should be given with incision.
• Preoperative steroids can decrease vasogenic edema,
alleviate headache and neck pain, decrease the
incidence and severity of aseptic meningitis and the
posterior fossa syndrome, and decrease nausea and
vomiting allowing for better hydration and nutrition
prior to surgery.
• Ensure availability of automatic retractor system.
6. Intraoperative monitoring
• Intraoperative monitoring may be helpful if there is
danger of violating the brain stem or cranial nerves.
• The most sensitive measure of alteration of brain stem
function is the pulse and blood pressure, since
cardiovascular reflexes are mediated by structures
near the fourth ventricle such as the nucleus tractus
solitarius and dorsal motor nucleus of the vagus.
• Any alterations in vital signs while working near the
floor of the fourth ventricle should be considered a
serious warning sign to stop manipulation.
7. • The best option for direct monitoring of brain-stem function
is brain-stem auditory- evoked potentials (BAEP), in which
an auditory click is measured at earlobe and vertex
electrodes.
• This produces five waves that correspond, respectively, to
the proximal cochlear nerve, distal cochlear nerve, cochlear
nucleus, superior olive, and lateral lemniscus/inferior
colliculus.
• Evidence of pontomesencephalic transmission of the
impulse implies that the brain stem has not been
compromised.
• However, this pathway is fairly lateral and may be preserved
in spite of serious damage to the central core of the brain
stem.
8. • Another monitoring technique, somatosensory
evoked potentials (SSEP), follows sensory signals
through the medial lemniscus, but this is also
some distance from the floor of the fourth
ventricle, and SSEP is even less sensitive than
BAEP.
• Finally, EMG with direct stimulation of the facial
nerve or lateral rectus can be used to verify
integrity of the cranial motor nerves if tumor
abuts or envelops them.
9. Positioning
• There are three possibilities for positioning: prone, lateral oblique, or
sitting.
• Each of the positions requires the head to be pinned using a Mayfield or
Sugita head holder as long as the patient is more than 2 years old.
• The pins are coated with an antibiotic ointment and placed two
centimeters above the ear in the unshaven scalp.
• It is important to avoid the squamous temporal bone and shunt tubing if
present.
• Use of pins in infants can lead to skull penetration producing depressed
fracture, dural laceration, hematoma, or postoperative abscess.
• Therefore, rather than using pins, very young children should be placed
face down with the head on a padded horseshoe, ensuring there is no
pressure on the eyes.
• All three positions require a certain amount of neck flexion, so caution
should be used if there is known preexisting neck pathology, especially a
craniocervical anomaly, spinal instability, significant cervical spondylosis,
or herniation of the cerebellar tonsils on preoperative imaging.
10.
11. Prone position
• The most commonly used position for the midline suboccipital approach
(especially in very young patients) is the prone position, in which the
patient is rolled after induction of anesthesia so that the face is toward
the floor.
• There are many advantages to this position: the anatomy is clearly
visualized, it is easy for two to work together since one operator can stand
on either side, and the multiple complications of the sitting position do
not occur.
• The most significant disadvantage of the prone position is venous
congestion that can lead to more significant blood loss, pooling of blood in
the operative field, and soft tissue swelling of the face.
• This congestion is much worse if the head is rotated and flexed, and is
improved somewhat by elevating the head above the level of the heart.
• Also, nasotracheal rather than orotracheal intubation can minimize
compression of the base of tongue and impairment of venous drainage of
the tongue and pharynx.
12. • The weight is distributed to minimize pressure points that can lead to skin
breakdown and neuropathy, especially at the ulnar nerve at the elbow, common
peroneal nerve across fibular head, and lateral femoral cutaneous nerve at the
iliac crest.
• Two longitudinal padded roles are placed under the patient, and the knees and
ankles are padded.
• The neck is placed in the “military tuck position” with moderate flexion of the
upper cervical spine (to open up the space between the foramen magnum and the
arch of C1) and less flexion of the lower cervical spine (to bring the occiput parallel
with the patient’s back).
• The chin and chest at least two fingers apart. Finally, the table is positioned so that
the neck is parallel to floor and the head is above the heart.
• The shoulders can be gently retracted toward the feet with some tape, and a strap
under the buttocks is helpful to prevent sliding.
• The surgeon and assistant then operate from either side using the microscope, and
the scrub nurse’s Mayfield table can be placed over the patient’s back.
13. Lateral position
• The lateral oblique or lateral decubitus position is similar to the prone
position, except that the patient is lying on his or her side.
• This allows superior visualization of pathology high in the fourth ventricle,
in the lateral recesses, and in the cerebellopontine angle.
• The posterior fossa contents do not sink inward as they do in the prone
position and the operative distance is more comfortable for the surgeon.
• The principle disadvantage of the lateral oblique position is that the
anatomy is not centered so the surgeon must visualize all structures
rotated.
• Also, it is constantly necessary to support the upper cerebellar
hemisphere to maintain exposure, although the lower hemisphere
naturally falls away.
• The patient is placed on the side with the dependent arm ventral on the
table. A soft roll or IV bag wrapped in foam is placed in the axilla of the
dependent arm to prevent brachial plexus injury or vascular compression,
and the dependent leg is padded with special attention paid to the fibular
head of the upper leg to avoid peroneal palsy.
14. Sitting position
• The third option for positioning is the sitting position, in which the patient is
positioned sitting upright so that the operative corridor is parallel to the floor.
• The sitting position offers a very clear operative field since blood and cerebrospinal
fluid drain out of the operative site.
• However, there are many risks to the sitting position. The most significant dangers
are cardiovascular instability and hypotension, air embolism, and subdural
hematoma.
• All patients should have an agitated saline echocardiogram to exclude right to left
shunt through a patent foramen ovale that could complicate air embolism and
presence of such a shunt is an absolute contraindication for the sitting position.
• Precordial Doppler ultrasonic flow and end-tidal CO2 should be monitored
throughout the case.
• The risk of subdural hematoma is greatly increased by presence of a shunt, and if
possible the shunt should be occluded prior to attempting an operation in the
sitting position.
• Other risks of the sitting position include tension pneumocephalus, cervical
myelopathy, thermal loss (especially in children), surgeon fatigue, and sudden loss
of CSF from enlarged lateral and third ventricles after removal of a fourth ventricle
mass lesion.
15.
16. • When applying the head holder, the pin sites must be
covered with Vaseline gauze to minimize entry of air
and the head taped to the head-holder for extra
support in case the pins become dislodged.
• The patient is elevated slowly into the sitting position
so that the foramen magnum is at the surgeon’s eye
level with both of the patient’s legs flexed at the knees
to prevent postoperative sciatica.
• The instrument table is placed over the patient’s head.
• Infants too young for pins may be taped to a padded
headrest to support the forehead and chin, but it is
probably safer to use the prone position.
17. • Throughout the case the patient should be carefully
monitored for signs of hypotension or air embolism.
• If air embolism occurs, the wound should be packed with a
saline-soaked sponge, and anesthesia should aspirate the
atrial catheter to attempt to remove the embolus from the
left atrium.
• If the embolus is severe, the patient should be placed in left
decubitus position; otherwise, as soon as the patient is
stable, the wound may be slowly exposed while covering
the potential source of air with Gelfoam and Surgicel.
• If careful preparation is undertaken and complications
dealt with promptly, the sitting position can be relatively
safe.
18. Preparation
• After positioning, the back of the head is shaved to expose
the suboccipital region and the scalp degreased with
acetone and alcohol then cleansed with a povidine iodine
solution.
• A linear midline incision is outlined 1-2 cm above the
external occipital protuberance down to the level of C4.
• The operative field is walled off with towels, draped with
iodoform adhesive, and infiltrated with 0.25% lidocaine with
1/400,000 epinephrine (or 0.1% lidocaine with 1/1,000,000
epinephrine in infants less than 1 year old).
• If there is concern that it will be necessary to rapidly
decompress the lateral ventricles intraoperatively or
postoperatively, a burr hole may be drilled in the right
posterior parietal region.
19. Incision
• The incision is made with a number 10 blade applying firm digital
compression, and bleeding points are coagulated.
• The incision should be midline, but if the tumor is lateral, a hockey-stick
incision can be used to allow for a wider craniectomy.
• The skin is undermined superficial to the fascia on both sides of the
superior half of incision in preparation to create a fascial flap for closure.
• The skin is then elevated with toothed forceps or a skin hook and a plane
of dissection developed with knife or monopolar coagulation, sparing the
occipital artery and nerve whenever possible.
• Even a slight deviation off midline will produce brisk bleeding from the
muscles once deeper tissues are exposed.
• When anatomical landmarks are identified to confirm that the operative
course is truly midline, cerebellar or Weitlaner retractors are placed to
maintain exposure.
• As deeper layers are exposed, curved retractors may be used.
20.
21.
22. • Next, the fascia is incised using a Y-shaped incision,
keeping the lateral ends of the Y below the
ligamentous insertion (nuchal ligament).
• While a linear midline fascial incision without the
upper limbs of the Y allows use of the avascular plane
between the splenius capitus and semispinalis capitis
muscles, it is often difficult to reapproximate such an
incision tightly at the superior nuchal line.
• Muscle flaps are then developed with monopolar
cautery and periosteal elevators, stripping the muscle
from the bone as far as the mastoid emissary vein.
23.
24. • This exposure is maintained with two curved
cerebellar retractors and the rostral flap is placed
under tension using a 3-0 silk suture to reflect it
rostrally.
• The muscle insertions are stripped off the
spinous process and laminae of C2.
• Finally, the junction between the pericranium and
dura at the foramen magnum is sharply
dissected, and then the posterior fossa dura
separated from the inner table of the occipital
bone using a curette.
25.
26. Craniotomy
• The suboccipital craniotomy is begun with burr holes on
either side of midline just below the transverse sinuses,
about three centimeters from midline.
• A third burr hole can be placed below the torcular in
older patients.
• In children, the dura is not firmly adherent to the skull
so it is safe to drill close to or even on top of the sinuses,
but more caution must be used with adults.
• The dura near the burr hole is then stripped using a
Penfield and the bone removed using a high speed drill.
• The superior and lateral limits of the craniotomy are the
transverse and sigmoid sinuses.
27.
28.
29. • Inferiorly, the craniotomy should always include the posterior edge
of the foramen magnum to prevent laceration of the brain against
the closed bony rim when cerebellar elements are retracted
downward and minimize damage from herniation if hematoma or
swelling should occur postoperatively.
• The midline bone is removed last since it is often very vascular and
contains a keel that can be quite deep.
• This keel must be stripped of dura with a Penfield, using extreme
caution near the occipital sinus in the midline and the annular sinus
near the foramen magnum.
• All exposed bone edges should be waxed, especially in the sitting
position.
• Because of the irregular contour of the inner bone surface in adult
patients, it is sometimes necessary perform a craniectomy rather
than a craniotomy, removing the bone in a piecemeal fashion.
30. • To expose the posterior arch of C1, the soft tissues
overlying it are reflected laterally using a small
periosteal elevator, stripping the inferior arch first since
the vertebral artery is on its superior aspect.
• It is sometimes easier to do this after C2 has been
exposed.
• The periosteum can sometimes be swept off the arch
of C1 using an index finger covered with gauze.
• Monopolar cautery should be used with caution when
dissecting the soft tissue over C1 (especially at the
superolateral surface) to prevent injury to vertebral
artery.
31. • It is important to remember that C1 can be bifid and is
often cartilaginous in infants and young children.
• C1 laminectomy is helpful for lesions that herniate beneath
the foramen magnum.
• To remove the lamina, small angled curettes can be used to
strip the deep surface of the bone, and then the bone itself
removed with an angled Kerrison punch or Leksell rongeur.
• Because extending a laminectomy below C2 in young
children increases the risk of swan neck deformity, it is
prudent to remove the smallest amount of bone possible.
• For most tumors, it is usually only necessary to remove as
far as one level above the most caudal aspect of the tumor.
32.
33. • Prior to the dural incision, the wound should be irrigated
and retractor systems and microscope prepared.
• If the dura is tense, the intracranial pressure can be
reduced with external ventricular drainage (if available),
hyperventilation, or mannitol, although* mannitol should
be used with caution in the sitting position as it has been
implicated in the development of subdural hematomas.
• All techniques for dural incision require crossing the
occipital and annular sinuses, which may be very large in
infants under age 2 years and can persist until 25 years of
age.
34.
35. • A Y-shaped incision allows wide visualization and can
be extended if necessary.
• One superior limb should be incised first with a
number-15 blade.
• The incision should start just inferior to the transverse
sinus and travel obliquely to the midline, stopping
short of the occipital sinus.
• The other superior limb is incised next, and then they
are connected over the midline.
• If there is significant bleeding from the midline
occipital sinus, it should be controlled with obliquely
placed hemostatic clips or suture ligatures.
36.
37.
38. • Either way, both the superficial and deep layer of the
dura must be incised or the sinus will be tented open.
• The vertical limb of the Y is opened last using scissors
so that the dura can be tented if bleeding is seen.
• The vertical incision extends to the foramen magnum
so that it will extend below the falx cerebelli, which is
occasionally present in childhood.
• If bleeding is very troublesome, the dura can be
opened paramidline.
39. • The dura is then covered with a moist collagen
sponge or wet Gelfoam sandwich to prevent
desiccation and anchored to the fascia with 4-0
neurolon suture.
• This allows wide exposure of the cerebellar
vermis and hemispheres.
• The arachnoid is opened next over the cisterna
magna to allow drainage of CSF.
• If the tumor is in the cerebellar hemisphere,
another dural incision can be extended laterally
to more fully expose the involved cerebellum.
40.
41.
42.
43. • Techniques for intradural exposure and resection of the
tumor will vary depending upon the location and size
of the tumor.
• Gentle separation of the cerebellar tonsils will expose
the cerebellomedullary fissure through the opened
vallecula giving an unimpeded view of the inferior roof
of the fourth ventricle.
• Narrow malleable automatic retractors can be used to
maintain separation of the tonsils; the retractor system
should be kept close to the patient so as not to
interfere with the subsequent operation.
44.
45. • The operating microscope is brought into the
field and the anatomy is identified.
• In particular, the location of the caudal loops of
PICA should be carefully noted since they are
often tethered to the tonsils and the walls of the
cerebellomedullary fissure by small perforating
branches.
• The foramen of Magendie and the small tuft of
choroid plexus protruding from it will be clearly
seen, as well as any tumor that protrudes from
the foramen.
46. • The thin layers forming the lower part of the roof can be
opened to expose sufficient exposure, but if not, it is
sometimes helpful to retract the inferior vermis rostrally or
incise the caudal vermis, avoiding the gutter between the
vermis and the hemisphere to prevent injury to the inferior
vermian veins there.
• Lateral lesions may require removal of one tonsil by
dividing the pedicle attaching the superolateral margin of
the tonsil to the biventral lobule.
• To reach the lateral roof or lateral recess, part of the
cerebellar hemisphere can be resected without significant
morbidity as long as the dentate nuclei are not violated.
47.
48. • If the tumor is not adherent to the floor of the
fourth ventricle, cottonoid patties should be
placed beneath the tumor to protect the delicate
brain-stem structures just beneath the floor.
• These cottonoids should be placed under direct
vision and never used as a tool to dissect the
tumor from the floor of the fourth ventricle.
• After the tumor has been removed, the glistening
white floor of the fourth ventricle should be
clearly visible.
49. • The retractors are then removed and the
cerebellar hemispheres allowed to fall back into
place.
• If there is extension of the tumor through one of
the foramina of Luschka into the cerebello-
pontine cistern, the ipsilateral tonsil and
cerebellar hemisphere can be retracted medially
to expose it.
• Sometimes it is necessary to do a secondary
retromastoid approach to completely resect the
tumor.
50. • The dura is closed using a running 4-0 neurolon
or polypropylene after approximating the dural
edges with interrupted sutures.
• A Valsalva maneuver will identify potentially
dangerous venous bleeding.
• The dural closure should be watertight if
possible, starting peripherally then working
centrally to gradually overcome the tension.
51. • If the dura is not watertight, there is increased
risk of pseudomeningocele due to a ball-valve
effect or hydrocephalus from arachnoid
adhesions produced by blood from the muscles.
• Sometimes the dura will be dried and shrunken
by the end of the case, especially if measures
have been taken to obliterate the occipital sinus.
In this case, the remaining defect can be covered
with a pericranial or fascial graft.
52.
53.
54. • Freeze-dried bovine pericardium or human
allograft dura can also be used, but use of
autogenous material is less likely to produce
postoperative aseptic meningitis.
• If clips were used on the midline occipital sinus,
they can be removed as the dura is sutured.
• The suture line may be covered with thrombin-
soaked Gelfoam.
• If a craniotomy was performed, the bone flap can
be secured with wires, plates and screws, or
sutures.
55. • Alternatively, the defect can be covered with a
titanium screen held in place by gently
compressing the screen and allowing it to
insert itself between the dura and inner
margins of the bony defect.
• The fascia is closed with interrupted
absorbable sutures to approximate the muscle
and fascia.
56.
57. • If the fascia is dried and difficult to approximate,
the skeletal fixation apparatus can be loosened
and the neck extended to facilitate closure.
• An adequate amount of tissue must be left at the
superior fascial flap to prevent buttonholes at
superior nuchal line.
• The scalp is then closed in layers, ending with a
subcutaneous re-approximation using interrupted
absorbable sutures with inverted knots.
58. • If in the sitting position, all layers should start
from the caudal end of the wound so that the
tails do not hang in the way.
• The wound is then closed with sutures or
staples.
• The wound is covered with a sterile dressing
and the patient extubated in a supine
position.
59.
60. Complications
• Hydrocephalus
• common
• In the past, many patients with tumors and hydrocephalus underwent temporizing
preoperative shunting to treat hydrocephalus and prevent pseudomeningocele,
CSF leak, and meningitis from fistula.
• However, more recently it has been observed that shunting is associated with
many complications, and the increased incidence of subdural hematoma,
infection, and brain-stem compression from upward herniation may outweigh its
benefits.
• Also, the advent of advanced radiographic imaging has allowed diagnosis of fourth
ventricular tumors much earlier than before, when patients were frequently
moribund with dehydration and malnutrition from vomiting and hydrocephalus
needed to be urgently treated.
• Today, only about 10% to 20% of patients with cerebellar and posterior fossa
tumors require permanent shunting and most of these have slow-growing tumors
such as astrocytoma since more acute tumors distend the ventricles for a short
period of time and do not allow outlet adhesions to form.
61. • Risk factors for shunt dependence include younger age, larger
preoperative ventricle size, and more extensive tumors.
• In many cases, preoperative high dose steroids will produce satisfactory
improvement in hydrocephalus.
• Otherwise, an appropriate alternative to shunting is perioperative external
ventricular drainage, especially if a patient presents lethargic or obtunded.
• This allows for precise pressure monitoring and control of drainage rate to
prevent upward herniation and, if continued postoperatively, clearance of
debris, proteinaceous blood, and air from the operation.
• Although external ventricular drainage does reduce the necessity to use
permanent shunts, the infection rate may be as high as 10%, so it should
be used judiciously.
• If a shunt is required for a malignant tumor, there may be an increased risk
of extraneural metastasis through the shunt tubing (especially to the
peritoneum), although some studies have suggested that such metastases
may occur as often in patients without shunts.
62. • Pneumocephalus
• Common - especially when patients are operated in the sitting position,
• common when patients have preoperative hydrocephalus, and frequently
results from overzealous drainage of CSF through an external ventricular
drain intraoperatively.
• *Since nitrous oxide can diffuse into air filled spaces, it is possible that
nitrous oxide contributes to tension pneumocephalus, although this is
controversial.
• If tension pneumocephalus is recognized intraoperatively, the patient
should be placed in Trendelenburg position and the operative bed
irrigated to replace air with the irrigating fluid.
• Symptomatic postoperative tension pneumocephalus can be treated with
a small frontal burr hole to relieve the pressure caused by the trapped air.
• Intraventricular air may cause ventriculoperitoneal shunt malfunction due
to airlock.
63. • Pseudomeningoceles
• Postoperative pseudomeningoceles affect 10% to
15% of all children with posterior fossa tumors.
• Normally, these are small collections of fluid that
respond well to serial lumbar punctures.
• Occasionally they can put the closure under
tension and eventually produce a leak, which
carries a risk of meningitis.
• Pseudomeningocele may be a manifestation of
hydrocephalus and in some cases may require a
CSF diversion shunt to control.
64. • Aseptic meningitis
• also called posterior fossa fever, is a rare occurrence after posterior
fossa surgery, especially for epidermoids or dermoids that rupture
intraoperatively leaking cholesterol cyst fluid, although it also
occurs after resection of astrocytoma or medulloblastoma.
• It may be a presenting symptom preoperatively but much more
common as a postoperative complication.
• Patients usually present about 1 week after surgery with fever,
headache, irritability, and CSF pleocytosis.
• It can be difficult in some cases to differentiate aseptic meningitis
from true bacterial meningitis, which should always be carefully
excluded before treating for aseptic meningitis.
• The condition resolves with steroid or anti-inflammatory treatment
and serial lumbar punctures to remove CSF.
65. • Cranial nerve palsies
• Transient or permanent cranial nerve palsies sometimes occur.
• The most common deficit is cranial VI and VII palsy caused by
disruption of the fourth ventricular floor along the facial colliculus
where the intrapontine course of the facial nerve loops around the
abducens nucleus.
• If this area is dissected or excavated, the deficit will often be
permanent, but even gentle diathermy with low-current bipolar can
produce a partial paralysis with total or near-total recovery.
• In most cases, patients with temporary facial weakness should be
treated to prevent corneal desiccation with artificial tears,
temporary tarsorrhaphy, or gold-weight implantation in the upper
eyelid.
66. • Permanent weakness has been treated with facial-hypoglossal
anastomosis, which can partially restore upper eyelid function.
• Abducens palsy is best treated with an eye patch to prevent diplopia (or
amblyopia if the patient is under 5 years of age); if the condition persists
beyond a few months, eye muscle surgery may be appropriate.
• Cranial nerve XII palsy can occur from injury to the hypoglossal trigone.
• While less common than facial palsy, this is a very serious complication
since it is usually bilateral since the nuclei are close together by the
median raphe.
• Patients present with dysarthria, swallowing apraxia, and continuous
drooling.
• When combined with cranial nerve VII or IX/X deficits, even aggressive
treatment with tracheostomy and feeding tubes may not prevent serious
complications due to aspiration.
67. • Skewed ocular deviation
• Skewed ocular deviation is a rare condition that is
sometimes seen after fourth ventricular surgery during
which the aqueductal opening is manipulated.
• This usually occurs with damage to the region of the
cerebral aqueduct.
• It is thought to occur because vertical yoking of eye
movements involves pathways that pass through the
periaqueductal gray matter in the mesencephalic
tegmentum.
• This condition usually resolves within weeks after surgery,
and can be avoided by gentleness when working around
the aqueduct.
68. • Posterior fossa syndrome
• The “posterior fossa syndrome,” also called
posterior fossa mutism or pseudobulbar palsy, is
characterized by the delayed onset of mutism,
emotional lability, and supranuclear lesions that
occurs within a few days after midline posterior
fossa operations.
• The syndrome has been seen in as many as 15% of
intraventricular approaches to lesions near the
brain stem, but has also been described with
supracerebellar infratentorial approach to the
pineal region and retromastoid lateral cerebellar
approach to the side or front of the brain stem.
69. • Patients present with global confusion, disorientation,
combativeness, paranoia, or visual hallucinations.
• They are generally alert and will follow simple commands, but will
sometimes refuse to speak or present scanning speech.
• Orofacial apraxia, drooling, dysphagia, pharyngeal dysfunction, and
flat affect are common, but there is no actual weakness, hence the
term pseudobulbar palsy.
• Because of the delay in onset, it has been suggested that edema
from operative manipulation may play a role, for example through
transmission of retractor pressure from the medial cerebellum
through fiber pathways along the middle and superior cerebellar
peduncles into the upper pons and midbrain.
• There are no consistent neuropathologic findings, and most
patients have some improvement over several weeks to months.
70. • Seizures
• Generalized and focal seizures
• The incidence is higher in faster growing
tumors and in the presence of ventricular
drainage or shunting.
• Late-onset seizures may be related to remote
hemorrhage, meningitis, or hydrocephalus.
71. • Ipsilateral limb ataxia, dysmetria, dysdiadokinesis, and hypotonia
usually results from damage to the cerebellar hemisphere,
especially the dentate nucleus, which is located along the
superolateral margin of the roof of the fourth ventricle adjacent to
the upper pole of the tonsil.
• Most injuries to the dentate nucleus occur during dissection of a
hemispheric tumor.
• Retraction during dissection of the superior vermis can injure the
superior cerebellar peduncle (which) producing similar symptoms.
• Unless the dentate is completely ablated, most patients recover
well within a few months with only minor residual intention tremor
that does not interfere with motor development.
72. • Since the superior and inferior cerebellar peduncles
make up the lateral walls of the superior roof of the
fourth ventricle, they are susceptible to damage during
intraventricular procedures.
• The superior cerebellar peduncle contains pathways
connecting the dentate nucleus to the red nucleus and
thalamus, so damage to the superior cerebellar
peduncle produces a similar clinical syndrome to
damage of the dentate nucleus with ipsilateral ataxia
and intention tremor.
73. • Injury to the inferior cerebellar peduncle
produces a syndrome similar to ablation of the
flocculonodular lobe with equilibrium
disturbances, truncal ataxia, staggering gait, and
oscillation of head and trunk on assuming erect
position without ataxia of voluntary movement of
the extremities.
• Injury to the middle cerebellar peduncle (which
causes ataxia and dysmetria) is rare during
intraventricular procedures, but can occur during
an approach to the cerebellopontine cistern.
74. • Postoperative dysarthria can result when
resections extend into paravermian part of
cerebellar hemisphere.
• This occurs more frequently from left
hemisphere injury than from vermal or right
hemisphere injury.
75. • Acute urinary retention is an uncommon complication of dissection
of the fourth ventricular floor near the striae medullaris,
presumably due to injury to the pontine micturition center in the
pontine tegmentum, the structure that integrates the cortex with
sacral and pelvic sensory pathways that apprise bladder filling
status.
• Patients with this condition demonstrate inability to initiate voiding
in spite of a full bladder with high intravesicular pressure.
• Since the pontine micturition center is deep in the pons near the
reticular activating system, this symptom is usually associated with
a disturbance in sensorium, but can occur in conscious patients.
• It is usually reversible but does not respond to detrusor augmenting
agents or alpha-adrenergic blockers.
• Patients are best managed by intermittent catheterization.
76. • Radiation hazards
• Patients treated with radiation sometimes have significant learning
disabilities, and should undergo follow-up neuropsychiatric
evaluation.
• Radiation treatment has also been associated with endocrine
dysfunction, growth dysfunction, hypothyroidism, delayed or
precocious puberty, and secondary malignancy.
• Patients that have extensive laminectomies are predisposed to
development of swan neck deformity, and should be kept in a soft
cervical collar for 6 to 8 weeks until the paraspinal muscles reattach
and monitored with cervical spine x-rays every few months for a
few years to check for spinal deformities.
77. • Injury to major vessels is rare.
• The most likely artery to be injured is PICA.
• Most patients with PICA injury present with postoperative flocculonodular
dysfunction with nausea, vomiting, nystagmus, vertigo, and inability to
stand or walk without appendicular dysmetria.
• Venous injury is extremely rare even if veins are sacrificed due to diffuse
anastomosis in this region.
• Veins near the tonsils, vermis, and inferior roof can be safely sacrificed.
• Medial retraction of the cerebellar hemisphere to expose the lateral
recess and cerebellopontine cistern can stretch bridging veins to the
sigmoid sinus, but it is seldom necessary to sacrifice these.
• Most venous infarctions of the posterior fossa have followed sacrifice of
the petrosal veins or veins of the cerebellomesencephalic fissure
(including the precentral cerebellar vein).