A manual of operative surgery . -sists in turning down a flap which includes scalp, pericranium, CHAP. I] CEREBRAL TUMOUR 4i and the subjacent bone. The flap should be more or less rect-angular with its attached base downwards. At each anglea half-inch disc of bone is removed by the conical the rapid formation of these openings Macewens trephinemay be used. This is made after the manner of a carpenterscentre-bit. The trephine itself is provided with a guard {seeFig. 212). The first opening being made in the usual way, thethickness of the bone is judged and the guard set for this.
A manual of operative surgery . -sists in turning down a flap which includes scalp, pericranium, CHAP. I] CEREBRAL TUMOUR 4i and the subjacent bone. The flap should be more or less rect-angular with its attached base downwards. At each anglea half-inch disc of bone is removed by the conical the rapid formation of these openings Macewens trephinemay be used. This is made after the manner of a carpenterscentre-bit. The trephine itself is provided with a guard {seeFig. 212). The first opening being made in the usual way, thethickness of the bone is judged and the guard set for this. Theother openings may be then rapidly made. This method is opento the objection that the guard can only be placed approximatelyowing to the varying thickness of the skull in different parts. A flexible metal director with a broad groove is then carefullyintroduced from one trephine hole to another, separating thedura mater and pushing it inwards. A hooked probe is nowpassed in the groove of the director, and by its means Giglis. FIG. 212.—MACEWENS TREPHINE wire saw is drawn through and the bone divided from within out-wards. It is well not to saw very quickly, as the narrow blademay become over-heated or break. Giglis saw is practically afret-saw. In using it the bone should be sawn obliquely, sothat, in the portion removed, the outer table is larger than theinner, reposition by this means being more accurate. All thefour angles of the bone-flap having been united by the saw-lines,it is turned downwards, with its overlying pericranium and bone may be divided with a chisel instead of by the abovemethod, the bone flap then corresponding in shape with that ofthe soft tissues (see Fig. 213). If the patient now manifests any sign of shock, the flap isreplaced, held in position by three or four sutures, and heis returned to bed, the second step being undertaken in six orseven days time. 42 OPERATIONS ON HEAD AND NECK [part hi The dura mater is now divided around about fou
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Keywords: ., bookcentury1900, booksub, booksubjectsurgicalproceduresoperative
