NeuroSurgery InfoNet

Plan

Consideration

patient

pathology

location

Option

position

incision

approach

Optimization

Strategy, objectives, logistics

Head trauma surgical planning considerations include the pathophysiology and location of the hematoma to be evacuated, the logistics of the operating room and hospital, and patient factors such as age and pre-morbid medical condition.

Having assembled all of the clinical and logistical data, the surgeon selects from possible exposures, positions, and incisions those that most safely and efficiently accomplish the objectives of surgery.

Considerations: Patient, Pathology, Location / Options: Position, Incision, Approach

Urgency

The urgency of surgery for evacuation of a traumatic intracranial hematoma is determined by the potential for neural tissue damage by the untreated lesion, as well as by the rapidity with which the pathophysiologic process can progress. The patient's neurologic condition and findings on head CT are the major clinical determinants of how urgently a head trauma craniotomy should be done.

Emergency operations are those for: 1. intracerebral hematomas which alone or with cerebral edema are causing transtentorial herniation. Epidural hematomas in patients who were initially GCS or 14 or 15 who suddenly deteriorate, as well as patients with subdural hematomas thicker than 2cm associated with mass effect and a GCS less than 14. A posterior fossa epidural hematoma, although usually due to venous bleeding, is also an emergency because of the limited volume of the posterior fossa in which it needs expand only a little to cause hydrocephalus and/or brainstem distortion.

Procedures that can be deferred beyond 2 weeks post injury are elective and include removal of foreign bodies from the scalp. Skull defects resulting from leaving out the bone flap during the closure for an emergency or urgent head trauma operations are also best repaired electively.

TABLE Urgency of operation

Strategy

Surgical strategy is the outcome of an interplay between factors related to 1. the patient, 2. the pathophysiology, anatomy, and prognosis of the  lesion, 3. the logistics of the hospital (Department of Emergency Medicine [DEM], Intensive Care [ICU], Operating Room [OR]), and 4. the technical ability, knowledge, experience, etc. of the surgeon him/herself.  

In addition to considerations of patient, lesion, and surgical options, strategy is determined by the objectives, the priorities, and the urgency of the intervention. The surgical strategy should at the same time maximize efficiency (speed), and cause no further harm to the patient (safety). Findings on neurologic exam and CT suggestive of recent or imminent deterioration should figure into strategic planning as should the logistics (personnel, policy, physical plant) of the hospital.

Objectives

The objectives of an operation for head trauma are to 1. Stop active bleeding, 2. Relieve compression or distortion of brain tissue by hematoma mass, 3. Reduce and control intracranial pressure, 4. Prevent infection, and 5. Preserve cosmesis. These objectives must be achieved as efficiently - rapidly and safely - as possible.

     Stop hemorrhage

Continued bleeding into a traumatic intracranial hematoma leads to increased mass effect and contributes to increased intracranial pressure. Whether from a lacerated middle meningeal artery (middle fossa epidural hematoma), or from torn bridging veins (frontotemporoparietal subdural hematoma) active bleeding can result in death and must be stopped.

     Relieve compression

Mass lesions compressing the brain at one site can cause focal injury and can result in herniation even in the absence of intracranial hypertension (medial temporal mass). When focal brain compression or distortion results in a concordant focal neurologic deficit (such as contralateral hemiparesis or aphasia), the indication for removal or reduction is more compelling than when there is no associated focal deficit.

1.3. Control ICP

According to the Monro-Kellie hypothesis: ICP within the non-expansible skull is due to three volumes - 1. Soft tissues (brain parenchyma and extra-vascular blood), 2. Intravascular blood, 3. Cerebrospinal fluid. Reduction of ICP requires reduction in one or a combination of these three volumes. Hyperventilation and dehydration decrease intravascular volume (at the expense of cerebral perfusion). Ventricular shunting allows egress of CSF with reduction in this volume. Diuresis and surgical interventions decrease the soft tissue volume.

1.4. Prevent infection

Dural closure and removal of contaminated foreign bodies is important for prevention of infection. Dural violation gives infectious pathogens access to the subarachnoid space as well as to the pial surface. Penetrating injuries result in deep tracts into the brain that can result in infection anywhere from the surface to deep within the parenchyma.

      Preserve cosmesis

The priorities of an operation for head trauma are, in order of decreasing importance: saving life, preserving neurologic function, and preventing long-term, non-life threatening, complications. Cosmesis is a long-term consideration.

Incisions placed on non-hair growing skin usually result in visible scars. The structure of the underlying bone is also important for cosmesis. If at all possible bones that support the face should not be disrupted. If part of a facial bone must be removed to gain adequate exposure to an intracranial hematoma its surface prominence should be left.

None of the commonly used craniotomies requires trauma to the face. Facial swelling and ecchymosis after surgery results from blood and serum tracking along tissue planes to dependent areas. This swelling is transient, resolving over a week or two in contrast to temporalis muscle atrophy and depressions over bone defects that are permanent.

Temporalis muscle atrophy gives the lateral aspect of the patient's face a sunken, wasted look. Creation of a muscle-sparing osteoplastic flap is an option whereas discarded bone flaps can be replaced with cement prostheses, no material yet available simulates the look and feel of lost temporalis muscle. Less disfiguring but more noticeable than temporalis atrophy is plegia of frontalis-innervated facial musculature resulting from an incision crossing this branch of the facial nerve.

The surgeon plans for closure of visible parts of the face, or forehead by having small needles and fine suture. (Such as 5-"0" nylon) available.

Although it may seem unimportant at a time when saving life is the paramount consideration, cosmesis will be the source of complaints from patients able to express their displeasure after head trauma surgery.

4.2.

    a) CT findings

        A temporal epidural hematoma is an indication for more emergent surgery, particularly if low-density streaks within the clot (indicative of active bleeding) are present. Subdural hemorrhaging has often stopped by the time the CT is obtained and enlargement of a clot seen on an initial study is usually more indolent than that of an arterial epidural hematoma, reducing the urgency of intervention.

Ominous findings on a CT scan that might raise the urgency of operation include hematoma in the temporal lobe or posterior fossa, obliteration of basilar cisterns, effacement of ventricles, and presence of multiple small contusions close enough to rapidly coalesce into an expanding mass lesion.

4.3. Timetable

The total time required for a craniotomy from the time general anesthesia is induced until the patients is transported to the recovery room or ICU is the sum of the time required for positioning, prep and draping, scalp, bone, and dural opening, hematoma and brain removal, obtaining hemostasis, closure, and dressing of the surgical wound.

4.4 Shortcuts

There are a number of shortcuts the surgeon can take to speed things up. Assuming that standard surgical technique is the collective technical compromise between the demands of patient safety and surgeon efficiency. A shortcut is a deletion of all or part of the standard surgical procedure. The surgeon takes a calculated risk with any shortcut. Good shortcuts are those which result in a significant time savings with minimal risk to the patient.

The need for speed may incline a surgeon more towards a smaller exposure that usually takes less time to create and close. Putting a patient's head on a donut supine and rotating it to get temporal or parietal access takes less time than configuring the body with an axillary roll, an arm support, and a Mayfield pin head holder.

Shaving the head can be complete or partial (just on either side of the incision) To adequately move the hair out of the incision and sterilize the area requires meticulous technique and more time than clippers followed by a straight edge razor. The time saved by not completely shaving the head may be consumed by trying to apply dressings, which are more difficult to stick to the skin with hair than without it.

The contact point pin cranial fixation takes a few minutes longer than resting the head on a donut. It requires experience on the part of the assistant. The risk of head movement during a procedure done in the lateral or three-quarter lateral position with the head in pins is less than in the supine position with the head on a donut.

TABLE Surgical timetable and time savings of common shortcuts

Because of the equipment and materials involved, whether the hair will be shaved entirely, partially, or not at all must be planned in advance; infection control is one reason for shaving of the head, with the hair goes bacteria, fungi, parasites, and other vermin which can contaminate a traumatic or surgical wound. Partial and no head shaving have been advocated in cases where the surgeon has time to comb the hair neatly back from the skin incision line in patients able pre-operatively to express a preference. Dressings are more easily applied and maintained clean when all hair is shaved. Oozing from the incision is sooner detected and more readily controlled.

The longer the incision, the longer the time to close and maintain hemostasis during the case. Shorter incision length and anesthesia-induced hypotension are strategies for minimization of blood loss and economization of time and energy.

Surgeon-extending powered instruments perform rapid repetitive motions faster than humans and should be used in the operative procedure whenever possible to speed things up. Prefabricated materials that act as dural and bone substitutes can save the surgeon time mixing, fashioning, and awaiting solidification. A variety of pre-fab cranioplasties are available. Dural substitutes save on time required to harvest a graft of pericranium or fascia lata. Plates and screws (instead of wire) save the time to pass and tie wire sutures and is stronger than fibers.

A straight line instead of curved incision saves time by obviating need for scalp clips, as well as length of time cutting, buzzing, and closing tissue. As long as the exposure with either a straight or a curved incision enables an exposure adequate to accomplish the surgical objectives, a straight-line incision is an acceptable short cut.

It would save time to use one instrument (the monopolar electrocautery) to incise all layers of the scalp rather than with slices with a blade followed by a hot knife. The problem with the monopolar for scalp division is at the skin layer where the electrocautery fries dermal cells even millimeters deep to the epidermal surface incision. The time saving probably does not justify the additional destruction of tissue attendant to hot knife to incise all scalp layers.

If the bone flap gets left out let it be for a better indication (such as to give the brain room swell post op) than to save time. But if the bone is left out to allow for post-operative swelling, don't close the dura. For this indication, namely saving time only, leaving the bone flap out is not acceptable.


Drilling fewer burr holes will save time but increases the likelihood, especially in elderly patients, of tearing the dura when cutting with the craniotome. A path is created with the dural separator between burr holes prior to cutting the bone with the craniotome. The fewer burr holes placed the more likely that the craniotome foot pedal would tear the dura. In extreme circumstances a dura tear may not be so important. Fewer burr holes will not save any time with closure. Overall, while not endorsed by any theoretical or scientific advantage, fewer burr holes is a time saving shortcut that rarely has any negative impact on patient outcome.

Over aerated sinuses where thinning of bone could lead to cerebrospinal fluid leaking from its intracranial confine to the extracranial. But where an inner and outer table separated by a soft tissue diploic layer overlie an opening in the dura, there is virtually no possibility of formation of a transosseus cerebrospinal fluid fistula. Close the dura if possible. Over the convexities, it is not necessary to close the dura. Skull base surgeons insist on water tight dural closure in their cases because the site of the dural opening is up against the intracranial inner wall of an aerated sinus communicating directly with the body surface and the outside world.

4.5. Extent of operation

In addition to removing masses resulting in focal brain compression and neurologic deficit, traumatic hematomas are also removed for reduction of intracranial pressure elevation. It is for the latter indication that adjacent or underlying brain may be removed at the same time as an intracranial hematoma. In the presence of cerebral edema the surgeon may opt to remove part of the normal frontal and/or temporal lobes.

Table: Extent of operation for intraparenchymal hematomas

5. Logistics

Logistical planning considerations include the difficulty and complexity of the proposed operation, personnel and plant of the institution where the surgery will be performed, and, for multiply injured patients, emergent extracranial operations to be performed prior to, during, or immedicately after a head trauma craniotomy.

5.1. Difficulty

Certain procedures are more assistant-intensive than others. Simpler craniotomies such as the parieto-occipital can be done efficiently single-handed, but others, such as the temporal craniotomy rely on a second set to hold retractors, irrigate, and suck.

5.2. Hospital

Constraints of hospital, equipment, and personnel are also planning considerations. Age and size of the facility as well as the technological level of equipment and instrumentation influence the kind of craniotomy that can be done. Surgical equipment must be located somewhere familiar to the staff and the staff competent to set it up and use it.

5.3. Combined procedures

In multiply injured patients the top priority is hemodynamic and ventilatory stability. Preservation of the nervous system is subordinate to preservation of life. Intracranial interventions may have to wait until imminent threats to heart, lungs, and other vital organs have been addressed and eliminated. Some procedures, such as placement of intracranial pressure monitoring devices and exploratory burr holds, can be performed simultaneously with thoracic or abdominal procedures but because of the risk of bleeding or other intraoperative problems, a craniotomy should not. Injuries to bones frequently accompany those to the head and brain, but is rarely life threatening to the extent that they take precedence over intracranial interventions for mass lesions with increased ICP.

Injuries to the head other than those intracranial may be of sufficient severity to require involvement of other services such as plastics, otolaryngology, and ophthalmology.

Optimization

Optimization includes complication prevention

Seizures

        Anticonvulsants should be given to prevent seizures in patients with lesions that put them at risk. Such lesion include subdural hematomas and intracerebral contusions.

Infections

        Antibiotics are an optional part of the pre-, intra-, and post-operative surgical management of head injured patients. Patients going to the ICU prior to craniotomy should receive a gram of a first generation cephalosporin within thirty minutes of going to the operating room and additional doses every eight hours thereafter.

Physiologic

Physiologic optimization planning considerations include measures that reduce metabolism in stressed brain such as pharmacologic coma and induced hyporthermia. Hematologic optimization is with transfusions of blood, platelets, and clotting factors. Oxygenation is the most essential of all of the physiologic optimization strategies required prior to craniotomy.

ICP monitoring

ICP monitoring when combined with monitoring of systemic blood pressure enables preoperative implementation of measures to optimize cerebral perfusion pressure.

Preoperative optimization measures can begin in the Emergency Room and be continued in the OR or in the ICU if the patient stops there on the way to surgery.

Priorities

The surgeon plans an operation that will accomplish the objectives in an order prioritized according whether they are related to preservation of life, neurologic function, or merely cosmesis. Once the procedure is organized and setup initiated the intervention is undertaken within the time frame appropriate to its degree of urgency: emergent, urgent, subacute, or elective.

Frequently because of the lesion itself or because of its pathophysiologic consequences, the surgeon will not be able to restore the patient to his premorbid condition. Surgical priorities in head trauma are, in order of importance: 1. Saving life, 2. Preservation of neurologic function (reversal of deficit, prevention of deterioration) and (less than 1. and 2. but important nonetheless, 3. Prevention of infection and 4. Cosmesis (preservation and/or restoration).

Dangers

Prior to operation the surgeon must take inventory of all dangers associated with the various surgical approach, exposure, and technical options. Such a survey of potential mishaps is essential for their prevention. As important as learning what to do in a crisis situation is knowing how to prevent its occurrence. The surgeon's confidence in his abilities and outcomes increases as he acquires the means to handle any intraoperative misadventure.

Any blood collection on CT suspicious for originating from or encompassing an occult vascular malformation should be investigated angiographically. In the event that an angiogram can not be obtained preoperatively, the surgeon must be prepared for the eventuality of sudden brisk uncontrollable bleeding. If the bleeding is arterial and rapid, it may be impossible to secure any vessel with a vascular clip although this would be the preferable mode of treatment. Vascular clips should be available if an AVM; or other vascular malformation is even remotely suspected.

Time

Intraoperative speed is more important in treating some kinds of intracranial pathology than in others. For a head trauma victim with an intracranial hematoma, speed can be important for two reasons: 1. Because of an ongoing pathophysiologic process that must be arrested within a short period of time or which will result in a neurologic deficit (epidural hematoma), 2. Because of an evolving process (such as cerebral swelling) that changes brain tissue in such a way that it becomes surgically unmanagable (such as when it mushrooms out through a craniotomy exposure).

For the surgeon speed is important also because of other demands on his time and because of the inevitable pressures of the hospital and OR trying to move patients efficiently through and to meet the needs of all who require urgent or emergency surgery.