63.5 Should you make burr holes, and if so where?

The patients who are worth great efforts to save are those whose consciousness is deteriorating, especially if they were fully conscious a short time ago. In order of importance, the factors to help you to decide are: (1) Deterioration in a patient’s level of consciousness. (2) The development of localizing signs, such as weakness on one side of his body. (3) Change in his pupils, as in Fig. 63-3. (4) A rise in his blood pressure. (5) A slowing of his pulse.

Figure 63.6: ANATOMY FOR CRANIOTOMY This is the order in which to make burr holes for an extradural haematoma. In a chronic subdural haematoma start with burr hole No. 2. Make burr hole ’X’ if the clot extends backwards under the parietal bone when you make burr hole 1.

As cerebral compression develops, a patient’s blood pressure rises and his pulse becomes slow, full, and bounding. These signs are evidence of a physiological attempt to maintain the circulation to a patient’s vital centres in the presence of cerebral compression. These signs are the reverse of those in internal haemorrhage, as from a ruptured spleen, for example, in which a patient’s blood pressure falls and his pulse becomes rapid and weak. As with consciousness it is the trends in his pulse and blood pressure which are important, especially if he is a child, rather than any particular value.

Restlessness, and particularly a very severe headache, are useful additional signs of intracranial bleeding in a conscious patient. Another suggestive sign is boggy oedema of his scalp over the site of a fracture.

Figure 63.7: PREPARING FOR CRANIOTOMY A, the sites of burr holes. You need to make an additional hole over the fracture. B, positioning the patient’s head so that you can get at all of it. C, draping his head so as to expose his ears and zygomas. After Graham Martin.

Don’t depend on the presence of a fracture. The signs which do not in themselves indicate the need for urgent exploratory burr holes include: (1) Focal neurological signs in an alert patient.

(2) A depressed skull fracture.

WHICH SIDE TO MAKE THE FIRST BURR HOLE?

Here are the localizing signs in decreasing order of reliability.

If, as occasionally happens, the X-ray shows the fracture side crossing a vessel, make the first burr hole there.

If you don’t have this useful localizing sign, make it on the side which: (1) Is bruised or lacerated. (2) Is stronger if one side of the body is weaker than the other. (3) Has a dilated pupil, or was the first to have one, if they are now both dilated. (If his pupil was dilated from the moment of the injury, and fails to react to light, he has an orbital injury, and the sign is not helpful.) (4) Shows less vigorous knee and ankle jerks, if these are unequal.

Rare localizing signs include focal epileptic fits, homonymous hemianopia which develops after the injury, and dysphasia.

WHERE TO MAKE THE FIRST BURR HOLE?

If the fracture crosses a vessel, make the hole there.

If a patient has an obvious scalp injury, make it in the centre of this.

If there is no fracture line or obvious scalp injury, make the first hole in the classical position in Fig. 63-9.

If the first hole is negative, make the next one in the parietal region, and then one in the frontal region.

If this too is negative, repeat the same three holes in the same order on the other side.

Figure 63.8: AN URGENT CRANIOTOMY. Alternatively, apply saline with a 20 ml syringe and a 20 Ch catheter. Maintaining sterility may be easier this way. Kindly contributed by Peter Bewes.

Occasionally, you will have to make six holes; only if they are all six negative can you be sure that there is no clot above a patient’s tentorium. He may still have a clot in his posterior fossa, but you have no practical way of diagnosing it. To begin with, each burr hole will take you an hour. Looking for a clot by this ’woodpecker method’ may be tedious, and is certainly less elegant than doing a CAT scan, but it is not difficult. Only when you have reached the dura will you see if the bleeding is outside or inside it. The one place not to make a burr hole is over a major sinus!