Neurotrauma

Head injury is a common problem that patients present with to the accident and emergency department. All patients that loose consciousness after a head injury should seek medical attention for further medical evaluation. Often after the injury, we may not have lost consciousness but are a little dazed then later complain of symptoms of nausea, vomiting, giddiness and headache. These symptoms can vary in severity and may or may not resolve after several hours.

Patients with persistent symptoms who present to the accident and emergency department are evaluated and a CT brain scan may be performed if warranted. Depending on the results of the scan, patients are managed accordingly. One may be observed for several hours after some medical treatment and discharged if they subsequently improve. They may be admitted for closer monitoring if there are positive findings seen on the CT brain scan. Most symptoms often resolve or improve after 24 to 48 hours. There are however usually some long term residual symptoms such as memory loss, lack of ability to concentrate, ringing in the ears, tenderness or abnormal sensations over the region of scalp that was hurt. These residual symptoms can remain for up to 1 to 2 months after the head injury. If symptoms persist, further consultations with your doctor may warrant additional investigations.

In a minority of head injury patients, however, a more serious intracranial injury may have occurred. Such patients include those who remain drowsy or confused, have nausea or vomiting, severe headache, convulsions, drainage of spinal fluid from the ear or nose, develop weakness or loss of feeling in the extremities, pupillary asymmetry, double vision, or other neurological symptoms. In these individuals, a more thorough evaluation and closer observation is indicated because the concussive event may have caused a skull fracture and/or a hemorrhage over the surface of the brain (epidural or subdural hematoma) or in the brain (contuision). The CT scan of the brain which is performed will reveal these findings.

The GCS is the most widely used method of defining a patient's level of consciousness and is used routinely by medical personnel to objectively describe a patient's neurological status. The patient's best motor, verbal and eye opening responses determine the GCS. A patient who is able to follow commands, is fully oriented and has spontaneous eye opening, scores a GCS of 15; a patient with no motor response, eye opening or verbal response to pain scores a GCS of 3. Patients with a GCS of 8 or less are considered to be in "coma". The utility of this scaling system is its objectivity, reproducibility and simplicity. When properly performed, the degree of inter-observer difference is negligible. Hence, a change in the GCS from one assessment to the next indicates a significant change in level of consciousness. It also has strong prognostic value in head injured patients regarding eventual neurological recovery. Head injury severity is generally categorized into three levels based on the GCS after initial resuscitation: mild: GCS 13-15, moderate: GCS 9-12, severe: GCS 3-8.

A subdural hematoma is a collection of blood over the surface of the brain. The brain is surrounded by cerebrospinal fluid and the fluid is in turn surrounded by 2 layers of membrane called the arachnoid(inner) and dura (outer). External to the dura is the skull bone. The reason the blood clot is called a subdural hematoma is because the blood is under the dura layer.

There are two types of subdural hematoma, acute and chronic. They are two vastly different conditions with different treatments and outcomes.

A chronic subdural hematoma is a collection of blood over the surface of the brain. It lies below the dura layer and it occurs after mild to moderate head trauma. This occurs especially in the elderly. There is gradual accumulation of blood which results from small veins lining the surface of the brain that are torn as a result of the injury. After some time, the blood clot gradually liquefies. However, in some individuals, the blood clot can expand over time and cause symptoms due to compression of the adjacent brain structures. This can usually develop over a period of several months.

The commonest symptom that occurs is the complaint of headache. Other symptoms include drowsiness, behavioral change, fits or weakness or numbness in one or more limbs. When such symptoms occur, one needs to be admitted to hospital for surgery.

The surgery is usually performed under general anaesthesia. The head is partially shaved and one or two skin incisions need to be made. Subsequently, one or two holes are drilled on the skull of about five cent coin size diameter. The membrane covering the brain is opened and the liquefied blood clots washed out. After surgery, one usually needs to remain in hospital for about 4 to 5 days before discharge.

An acute subdural hematoma is a rapid accumulation of blood below the dura membrane layer covering the brain. This usually occurs after a severe blow to the head such as after a hard fall or after a motor vehicle accident. The accumulation of blood occurs from damaged arteries on the surface of the brain and usually causes significant compression of the surrounding brain structures. The result is that one may become immediately unconscious or fall into a semiconscious state after the injury. There is usually associated injury to the surrounding brain tissues as well from the impact of the head injury. This may include skull fractures, extradual hematoma or intracerebral hematoma.

An emergency craniotomy will need to be performed as a life saving procedure to remove the blood clot and to prevent further brain injury.

An extra dural hematoma is an accumulation of blood on the surface of the brain outside of the dural layer. This occurs after a head injury where there is a severe blow causing a tear in arteries on the dura membrane layer. There is rapid collection of blood which causes compression of the adjacent brain. There is often associated skull fractures with such injury.

An emergency craniotomy also needs to be performed as a life saving procedure to remove the blood clot and to prevent further brain injury.

An intracerebral hematoma is a collection of blood clot within the brain substance. This occurs in the context of trauma after the head has sustained high impact injuries. When such events occur, the brain is shifted about within the skull and the forces that the brain encounters results in twisting and tearing of blood vessels within the brain substance and on the surface of the brain. Such injuries occur concomitantly with extradural hematomas, subdural hematomas or skull fractures depending on the severity of the injury.

The collection of blood clot within the substance of the brain can gradually expand and will push against the surrounding brain tissues. This can compress on vital blood vessels as well as important nerves in the surrounding region. If the clot is very large, it can also compress on vital areas of the brain stem that control our heartbeat and breathing. The brain tissue that is injured is often also associated with surrounding brain swelling which can worsen the problem.

If the blood clot is small, the patient needs to be monitored closely for progressive deterioration from an enlarging clot. If the blood clot is large and the patient is already unconscious, then surgery needs to be performed urgently for evacuation of the blood clot and to relieve pressure from the surrounding brain structures.

Patients with such injuries are often critically ill and require admission to the intensive care unit (ICU) for management. The main issue is that of diffuse swelling of the brain which can compromise blood flow to the brain resulting in further damage from stroke. The patient is usually kept sedated with medications and put on a ventilator to control the breathing. Various other medications may also be given to help reduce brain swelling as well as to control the patients blood pressure.

A fracture occurs when there is a break in part of the skull bones. The skull bone serves to protect our brain from external injury. A fracture of the skull occurs when there is a heavy blow to the head. This can occur after a fall, road traffic accident or being hit on the head by a hard object.

There are several types of skull fractures with varying severity as follows:

Due to the impact that is sustained to cause a skull fracture, such injuries may also be associated with injuries to the underlying brain. In simple skull fractures such as a liner fracture or mildly depressed skull fracture, there is no need for any major operation to repair the fracture and healing will take place on its own over the next few weeks. If there is a more complex compound fracture, then one will have to be taken to the operating theatre to clean the scalp wound and for surgery to lift up the depressed bony fragments and repair the torn membrane lining the brain. In some circumstances when there is extensive injury to the bone and brain, portions of the cracked skull will be removed and later reconstructed with synthetic materials or a metal mesh. This procedure to replace the bone is called a cranioplasty.

Base of skull fractures are usually managed conservatively if there is no leak of cerebrospinal fluid (CSF). The fractured bones will heal and unite with time. In the event that there is cerebrospinal fluid leakage, a very fine plastic tubing called a lumbar drain will have to be inserted via the lower back in the ward to allow an alternative route for the CSF to flow. This will give time to allow the torn area of membrane to heal up. In the unlikely event that this does not occur then surgery will need to be performed to repair the area of torn membrane.

A craniotomy is a neurosurgical procedure to gain access into various locations of the brain. Depending on the location of blood clot, a curved skin incision is made at a particular location of the head to lift up a portion of the scalp and expose an underlying region of bone. Drills and special bone saws are then used to cut around part of the skull and remove a disc of bone. The membrane overlying the brain is then exposed and this layer is then further cut opened to expose the underlying brain surface.

This procedure is generally similar for operations to remove extradural, subdural or intracerebral hematomas. The membrane covering the surface of the brain is opened for surgery to remove subdural and intracerebral hematomas but it is not performed if a patient only has an extradural hematoma.

At the end of the operation after the blood clots are evacuated from the various locations, everything is replaced as it was before the operation. The membrane covering the brain surface is stitched back and the bone is replaced and secured with screws or wires. If there is extensive swelling of the brain in certain circumstances, the bone may not be replaced and the scalp is just closed over the bone defect and the skin stitched close. A cranioplasty may then be performed at a later date to replace the bone.

This is a surgical procedure to reconstruct a portion of bone of the skull that was previously removed. The reasons for performing this procedure are for cosmetic purposes and for protection of the underlying brain. In certain circumstances, it can help to improve neurological function as well as to relieve headaches in patients where there is a large defect after previous removal of the bone.

The materials used to repair the defect can be the previously removed bone if it remains intact, or other materials such as a titanium mesh or plate and synthetic acrylic materials that can be shaped to match the contour of the skull bone.

The procedure is performed under general anaesthesia which lasts about 2 hours. During the procedure, the scalp over lying the bony defect is lifted up through the previous scar and the bone or synthetic material is shaped to fit the defect and secured with metal plates and screws or wires. The expected duration of hospital stay is about 5 days.