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Definition:

Craniotomy is a surgical operation in which part of the skull, called bone flap, is removed in order to access the brain.

Purpose: Its the most commonly performed surgery for

brain tumor removal . It is also done to remove a blood clot

(hematoma), to control hemorrhage from a weak, leaking

blood vessel (cerebral aneurysm), to repair arteriovenous malformations

(abnormal connections of blood vessels), to drain a brain abscess, to relieve pressure inside the skull, to perform a biopsy, or to inspect the brain.

Patient’s profile:

Patient X29 year oldMaleResiding at Halseb, Tublay BenguetBorn on January 1, 1982Had sudden fall resulting to severe

head trauma, hence admission.

PRE-OP & POST- OP DIAGNOSIS: Right temporal lobe cerebral contusion, right temporal subdural hematoma, right parieto-occipital epidural hematoma

OPERATION PERFORMED: Emergengency right subtemporal craniectomy excavation hematoma, temporal lobectomy, drain

THE NERVOUS SYSTEM: Two parts:

PHERIPHERAL NERVOUS SYSTEM: composes the nerves extending to and from the brain and spinal cord.

CENTRAL NERVOUS SYSTEM: consists of the brain and spinal cord, which are located in the dorsal body cavity.

Function of NERVOUS SYSTEM

The primary functions of the nervous system are to monitor, integrate (process) and respond to information inside and outside the body.

ANATOMY OF THE HEAD:1. SKIN a protective barrier against

physical damage of underlying tissues,

invasion of hazardous chemical and bacterial substances and,

through the activity of its sweat glands and blood vessels, it helps to maintain the body at a constant temperature.

2. SKULL is a highly complex

structure consisting of 22 bones altogether.

These can be divided into two sets:cranial bones

(cranium) facial bones

FACIAL BONES: form the framework of the face.

CRANIAL BONES: form the cranial cavity that encloses and protects the brain.

FRONTAL BONE: forms the forehead and contains the frontal sinuses, which are air filled cells within the bone.

PARIETAL BONEs: form the most superior and lateral aspects of the skull

OCCIPITAL BONE: forms the posterior aspects of the skull

3. MENINGES are three connective

tissue membranes enclosing the brain and the spinal cord.

Their functions are to protect the CNS and blood vessels,

enclose the venous sinuses, retain the cerebrospinal fluid, and form partitions within the skull.

THREE LAYERS OF THE MENINGES:

1. DURA MATER: the outermost layer; it is tough white fibrous connective tissue.

2. ARACHNOID: the middle layer which resembles a cobweb in appearance, is a thin layer with numerous threadlike strands that attach it to the innermost layer.

3. PIA MATER: is the innermost layer of meninges.

CEREBROSPINAL FLUID: a watery liquid similar in composition to blood plasma.

The prime purpose of the CSF is to support and cushion the brain and help nourish it.

ANATOMY OF THE BRAIN

The major regions of the brain are the:

cerebral hemispheres

diencephalon brain stem cerebellum

THE BRAIN:

consists of soft, delicate, non-replaceable neural tissue.

It is supported and protected by the surrounding skin, skull, meninges and cerebrospinal fluid.

1. CEREBRUM: located on the most

superior part of the brain, are separated by the longitudinal fissure.

It is responsible for conscious behaviour

and contains three different functional areas: the motor areas, sensory areas and association areas.

2. DIENCEPHALON: located centrally within

the forebrain. It consists of the

thalamus, hypothalamus and epithalamus, which together enclose the third ventricle.

relay station for sensory inputs ascending to the sensory cortex and association areas.

It also mediates motor activities, cortical arousal and memories.

3. Brainstem: The brain stem is the

region between the diencephalons and the spinal cord.

It consists of three parts: midbrain, pons, and medulla oblongata.

The midbrain is the most superior portion of the brain stem.

The pons is the bulging middle portion of the brain stem.

4. CEREBELLUM: the second largest

portion of the brain, is located below the occipital lobes of the cerebrum.

processes impulses received from the cerebral motor cortex, various brain stem nuclei and

sensory receptors in order to appropriately control skeletal muscle contraction, thus giving smooth, coordinated movements.

The cerebral circulatory system Blood is transported through the body via a

continuous system of blood vessels. Arteries carry oxygenated blood away from the

heart into capillaries supplying tissue cells. Veins collect the blood from the capillary bed and

carry it back to the heart. The main purpose of blood flow through body

tissues is to deliver oxygen and nutrients to and waste from the cells, exchange gas in the lungs, absorb nutrients from the digestive tract, and help forming urine in the kidneys.

However, there is little communication between smaller arteries on the brain’s surface.

Hence occlusion of these arteries usually results in localised tissue damage.

The major arteries are the vertebral and internal carotid arteries.

The two posterior and single anterior communicating arteries form the circle of Willis,

which equalises blood pressures in the brain’s anterior and posterior regions,

and protects the brain from damage should one of the arteries become occluded.

HEAD INJURY(TRAUMA)

tiny veins between the surface of the brain and its outer covering (the dura) stretch and tear,

allowing blood to collect

bleeding fills the brain area very rapidly, compressing brain tissue

SUBDURAL HEMATOMA (nerve damage)

INFLAMMATION AND PAIN(increase intracranial pressure)

BRAIN TISSUE DAMAGE(coma/ death)

hematomas are usually the result of a serious head injury

The bleeding fills the brain area very rapidly, compressing brain tissue. This often results in brain injury.

With hematoma, tiny veins between the surface of the brain and its outer covering (the dura) stretch and tear, allowing blood to collect.

In the elderly, the veins are often already stretched because of brain atrophy (shrinkage) and are more easily injured.

The blood vessels in the body are under constant repair. Minor injuries occur routinely and the body is usually able to repair the damaged vessel wall by activating the blood clotting cascade and forming fibrin patches.

Sometimes the repair fails if the damage is extensive and the large defect allows for continued bleeding.

As well, if there is great pressure within the blood vessel, for example a major artery, the blood will continue to leak and the hematoma will expand.

Blood that escapes from the blood stream is very irritating and may cause symptoms of inflammation including pain, and swelling.

Signs and symptoms of Subdural hematoma: vomiting, difficulty tolerating bright lights, leaking CSF from the ear or nose, bleeding from the ear , speech difficulty, paralysis, difficulty swallowing, and numbness of the body. nausea, dizziness, irritability, difficulty concentrating and thinking, amnesia.

MANAGEMENT OF SUBDURAL HEMATOMA GOAL: reduce pressure on the brain Circulation support: IV fluids and medications to

control blood pressure. Respiratory support: Oxygen and mechanical

ventilation Dexamethasone: to decrease the inflammation

of the brain. (corticosteroid) Mannitol: to decreas swelling of the brain

(diuretic) Dilantin: to prevent or control seizure Coumadin and Heparin: anticoagulants Emergency surgery: Craniotomy to remove the

hematoma.

PREPARATION OF THE PATIENT:

a.Anesthesia: used was combined spinal epidural anesthesia ○ Craniotomy may be performed

under general anesthesia

b. Draping and positioning

The surgeon usually prefers to do the draping.

Folded towels are placed around the operative site and secured by towel clips.

The body and the head of the patient is properly draped exposing only the site that will be incise.

POSITIONING:The position of the patient depends upon the

location of the lesion and the preference of the surgeon.

c. Skin preparation:

The patient's scalp is shaved in the operating room just before the surgery begins.

The skin incision is usually made behind the hairline (dashed line)

PREPARATION OF THE PATIENT Before surgery the patient may be given medication

to ease anxiety and to decrease the risk of seizures, swelling, and infection after surgery.

Blood thinners (Coumadin, heparin, aspirin ) and non-steroidal anti-inflammatory drugs (ibuprofen, Motrin, Advil, aspirin, Naprosyn, Daypro) have been correlated with an increase in blood clot formation after surgery.

These medications must be discontinued at least seven days before the surgery to reverse any blood thinning effects.

Additionally, the surgeon will order routine or special laboratory tests as needed.

The patient should not eat or drink after midnight the day of surgery.

CASE DISCUSSION:

PROCEDURE:

In a craniotomy, the skin over a part of the skull is cut and pulled back (A). Small holes are drilled into the skull (B), and a special saw is used to cut the bone between the holes (C). The bone is removed, and a tumor or other defect is visualized and repaired (D). The bone is replaced (E), and the skin closed (F).

Removal of the bone flap is done in the following manner:

1. A series of small holes (bur holes) are made in the skull. The holes are positioned around the periphery of the proposed bone flap.

2. The skull is cut between each two adjacent burr holes in a progressive manner until the bone flap is separated from the surrounding skull.

3. After the bone flap is removed, the underlying dura is cut to expose the lesion. The dura is then cut within the margins of the skull opening.

After removal of the hematoma: The bone flap is wired back. Burr holes may be covered with

silicone rubber buttons, methymathcrylate, or autogenous bone chips.

As the scalp is closed, skin clips are removed.

The wound is dressed and the head is wrapped in a turban-like gauze bandage.

INSTRUMENTS:

Raney clips Raney clips

compress the scalp between the Galea and the skin surface to stop bleeding. 

Cushing and Adson elevators

After the scalp incision is made, the scalp tissue is peeled back with periosteal elevators such the Cushing and Adson elevators.

Gelpi or Weitliner retractor A small sharp drape

clamp can be used to grasp Galea and muscle tissue, followed by a rubber band for retraction, then anchored to the drapes with an atraumatic drape clamp.

A Gelpi or Weitliner retractor may be used with linear scalp incisions, or for suboccipital incisions, where heavier muscle tissue needs retraction.

Prior to turning a bone flap, a burr hole is initiated with a cutting drill bit.  This one is a pine cone shaped cutting bit.

During drilling, irrigation is used to reduce heat build up from bone friction.

Bone dust created from drilling may or may not be collected by the nurse or assistant, for use at the end of the craniotomy.  This is a surgeon preference.

Penfield elevators Penfield elevators are

referred to by their numbered names 1, 2, 3 and 4 (respectively from top to bottom in photo provided).

They have various ends on each instrument.

They can be used for various reasons such as periosteal elevators, soft tissue dissection, used for bone wax placement for bone hemostasis in small to reach places

side-cutting craniotomy blade

The side-cutting craniotomy blade is used after the burr holes are made.

Irrigation is necessary during bone drilling to reduce friction heat.

It is necessary to have a hold of the bone flap prior to the final boneflap cut (by the assistant or nurse), to avoid the boneflap dropping off the sterile site, as it is slippery

Cushing Brain Spoon/Protector

This is used to protect brain tissue from trauma; i.e. when power drill is used on bone in close proximity to brain tissue.

Cottonoids

Cottonoids are used for hemostasis, soft tissue protection and for tissue dissection.

They have both x-ray detectable markers and strings attached.

Kilner Suction The suction is used to

keep a wound dry of fluid. It can also be used for tissue manipulation.

The intensity of the suction increases when the air port is covered by the users thumb.

The suction tip should be inspected to ensure the end is not damaged, which can lead to tissue trauma.

Dural Opening: Sharp Dural Hook The sharp hook is used

initially during dural opening.

It's sharp end is used to elevate the dura from the arachnoid  layer (directly below the dura), to safely incise without damaging other layers or brain tissue.

At this point, dural opening has been initiated.

McKissack Scissors

McKissack scissors are used for dural opening, and can be used on brain tissue if applicable.

There appearance is similar to the Metzenbaum scissors, but are smaller, finer and used on delicate tissue.

They should not be used for cutting sutures.

Potts Scissors

Potts scissors are used on delicate soft tissue, such as for dural opening (surgeon preference), or for incising vessels, and at times used to cut brain tissue.

The tip is angled in varying degrees, for ease of use. 

All instruments should be moist if used on brain tissue.

Dural Opening: Grooved Director The Grooved director

may be used to assist in dural opening after the initial nick  is made into the dura.  

It is placed just under the dura,  guiding  the scalpel blade, while protecting the underlying brain tissue, as the dural  incision is made.

Dural Opening: Fine Needle Driver 3-0 or 4-0 traction

sutures may be placed at the outer edge of the dura mater with a fine dural needle driver.

At the end of the operation, the dura is approximated with a Vicryl or Prolene suture on a fine dural needle driver.

Brain Retractors

Brain retractors should be dipped in saline before touching brain tissue, to avoid tissue trauma.

A moist cottonoid may be used between brain tissue and retractor.

Ventricular Cannula (Dandy Needle) This cannula is used for

ventricular localization and catheter placement.  It can also be used for brain cavity fluid aspiration, such as CSF or abscess fluid.

It is often used with a syringe for aspiration.  It is marked in centemeter increments.  At times, a ruler is used to measure cannula depth.

Leksel and Ruskin Rongeurs These instruments are

used for bone dissection for gaining exposure during craniotomies.

They are also well known for their use in spinal procedures.

Angled Kerrison Rongeur The Kerrison rongeur is

used to remove bone.  It takes small 'bites' of bone at a time.  It comes in various sizes and angles.

When used, upward traction must be used during placement and use to prevent trauma to soft tissue below the bone      (i.e. dura).

The small screw along the grip should be checked prior to and during use, to ensure it does not become loose during use.

Cranial Plates and Screws Cranial plates and screws

are used to replace the bone flap at the end of the craniotomy.

The above picture displays a straight plate and a small and large disc plate, often used to cover burr hole defects.

The implants are titanium. The screws are manually

self-drilling, not requiring a power drill.

It is necessary to record the number of plates and screws used to the circulating nurse for documentation.