As the brain is to be covered in after the operation, a large horseshoe-shaped osteocutaneous flap with a diameter of about three inches, the base turned toward the source of the blood-supply, is probably the most effective manner of uncovering the brain. It should be cut in one piece so as to permit of being turned down. This breaking down at the base is facilitated by cutting across the bone with sharp forceps, or other wise, and it should be so cared for dur ing operation that the skin and bone are not torn asunder; it may be necessary to envelop it in a cloth wrung out in hot, sterile, salt solution.
The patient being in the semirecum bent position, in order to diminish the amount of haemorrhage, the fissures–Lso far as desired—may be marked on the scalp with an aniline pencil; and also three points on the bone beneath—the point at which the centre-pin of the trephine is to be applied, and the upper and lower ends of the fissure of Rolando at points just outside the flap; the centre-pin of another trephine may be used for this purpose. The cutting of the bone is to be done by the instrument with which the surgeon is most familiar; the trephine, the rapidly-revolving saw, chisel and mallet, the Gigli wire saw, all have their advocates. Should the opening not be large enough in the skull, there should be no hesitation to cut away the borders of the opening with rongeur forceps until sufficiently large.
The wire saw in resecting a portion of the cranium is used as follows: Having decided upon the outline of the three sided flap which is to be turned down, two small incisions are made at the upper corners just sufficiently large to allow the application of a small trephine. As soon as the holes have been drilled a director with a beak turning off almost at a right angle, and grooved so as to properly direct a thin piece of whale bone between the dura and bone, is in serted with the beak placed between the (Lira and skull. The whalebone threaded on the end with a long piece of strong and thin silk is then pushed gently on in the direction of the other trephine opening until it comes in view, when the thread is partially drawn out. Each of the remaining sides of the flap is treated in a like manner. One end of the thread is attached to a wire screw, and the saw drawn through between the skull and the whalebones. The skin-incisions are now completed and the bone sawed through. Leonardo Gigli (Centralb. f. Chin, No. 10, '98).
There is a difference between the sides of the skull and the top; bone need not be put back in the temporal fossa, for, by reason of the presence of the dense temporal fascia, there is not much sink ing in; it is otherwise at the top and front of the skull, as an absence of bone results in a deep depression. The time
consumed in exposing the brain is largely the result of the bone-cutting. It is therefore a matter worthy of thought and careful consideration whether, when it becomes necessary to operate within the head, it may not be expedient to raise a large flap, remove one-third of an inch internal to the bone-section, so as to allow of suturing and replacement. In general, the dura is to be respected and treated like other serous membrane, and with no more consideration.
IImmorrhage from the skin may be arrested with Immostatic forceps. With a transverse bar at the top, a T-shaped blade, a large area of skin would be pressed upon and bleeding be better arrested; perhaps the T-shaped blade could, with advantage, be covered with rubber. Encircling the cranium with a rubber band has yielded satisfactory re the necessary bone, replace the flap, and allow it to heal. A month or two after ward the surgeon can operate to remove the pathological condition more rapidly, bone not obstructing.
All operations on the brain should be done in two, or even more, stages, with a few days' interval between. A. Chi pault (Gaz. des May 26, '93).
It has been observed that opening the skull, even in incurable cases, may di minish pain and optic neuritis. The dura is to be divided and turned aside as a flan. the line of division being about sults. Hemorrhage from the bone dur ing the cutting may be arrested by Horsley's aseptic wax, or pressure with dry gauze. By crushing in the edges of the bone with heavy forceps bleeding from the diploe may usually be arrested. In hwinorrhage from the dura a fine ligature passed around the artery and tied suffices to stop bleeding. Venous hemorrhage may be arrested in the same manner. Hemorrhage from a sinus may be arrested in several ways: by suturing the wound in the vessels with a curved needle, passing the thread around it and tying it, and by gauze pressure. After turning the dura back and exposing the surface of the brain, bleeding-vessels are to be looked for and tied carefully, with out dragging, by two ligatures, and di vided between. Forceps will generally tear off, and should not be employed, save very temporarily. Serre-fines may be of use.