CHAPTER II. The Special Technique in Operations on the Skull and Brain

THE SPECIAL TECHNIQUE IN OPERATIONS ON THE SKULL AND BRAIN

=Preparatory treatment.= Where possible at least two or three days should elapse between the admission of the patient and the day of operation. During this period the patient should be confined to bed with all possible cheerful surroundings. The bowels are regulated and the diet restricted.

The extent to which the scalp should be shaved and the time at which this procedure should be carried out vary according to the circumstances of the case. Much depends on the sex and age of the patient and the nature of the proposed operation. Insomuch, however, as it is always inadvisable to prolong the period of anæsthesia, it follows that the shaving should be carried out previous to the operation. With regard to extent, each case must be judged on its own merits. For instance, considerable concession must be made in the case of a young woman on whom the surgeon proposes to carry out a subtemporal decompression operation, and in the case of a neurotic or elderly patient who is the subject of trigeminal neuralgia. There can, however, be no question that the limitation of operative field advocated by some surgeons is fraught with considerable risk from the point of view of wound infection.

If the question be discussed with the patient the surgeon will find the ground cut away from beneath his feet, and that he has to make considerable and inadvisable concessions. Taking everything into consideration, although it is seldom necessary to shave the whole head, I am accustomed to order such preparation as will allow of a very wide margin. To shave the whole head is not only unnecessary but is also exceedingly distasteful to the patient. The front, back, or side of the head should be prepared only--on the morning of the operation, so as to allow of a comfortable night’s rest. After shaving, the scalp is thoroughly cleansed with soap and water, and the head surrounded by a sterilized towel. The final skin sterilization is carried out when the patient is under the anæsthetic.

The iodine method has always given satisfactory results, the skin being painted, half an hour previous to operation, with a 2¹⁄₂ per cent. solution of iodine, and again after the administration of the anæsthetic. Still, I cannot avoid a certain penchant for the older method--sponging with ether to remove the fats, washing with a 1 in 500 spirit solution of biniodide of mercury, and finally douching with a weaker mercury solution.

=Precautions against the development of shock.= It is almost inevitable that all serious head-operations should be associated with some degree of shock, though, from my experience, I am convinced that, with due precautions, it is far less serious than is generally supposed. The development of shock is very largely dependent on the amount of blood lost during the operative procedures. The various methods adopted to control hæmorrhage are enumerated later. In addition, attention should be paid to the following details:--

1. Half an hour before the operation an injection of a quarter of a grain of morphia should be given hypodermically. The addition of one-hundredth of a grain of atropin, recommended by some surgeons, interferes somewhat, by its action on the pupil, with the data deemed necessary for the administration of the anæsthetic.

2. The theatre should be maintained at a temperature between 65 and 75 degrees Fahrenheit. The table should be suitably warmed.

3. The patient’s body should be covered with warm blankets, and, in the more serious cases, the lower extremities may be bandaged, from below upwards.

It has been recommended that the brain, if exposed, should be protected from the cooling effects of the atmosphere by irrigation with saline solution at a temperature between 110 and 115 degrees Fahrenheit. Personally I prefer to keep the operative field as dry as possible.

An assistant should be told off, whose duty lies in keeping a record both of blood-pressure and pulse-rate. The lowering of blood-pressure is the surest guide to the surgeon of approaching danger.

It is often considered that rapidity of operation is essential. There can be no greater error. To ensure success the utmost care must be taken to control the loss of blood, for which it is essential that each step of the operation should be carried out deliberately and carefully.

=The anæsthetic.= Needless to say, it is essential that the surgeon should have at his disposal an anæsthetist of great experience in head operations.

Ether is regarded with favour in the United States, and in other countries, but we prefer chloroform on the ground that, by its lowering effect on the blood-pressure, there is less venous oozing, and added to this there is probably less tendency to post-operative vomiting. I have recently had the opportunity of seeing the open ether method as carried out in the States, on one occasion for an operation lasting four hours, and in this and in other cases the patient left the operation table in excellent condition, recovering also rapidly from the effects of the anæsthetic.

The lowering of blood-pressure as produced by chloroform might be advanced as an argument against the use of that drug, shock being the greatest danger to be feared in these operations. Still, I must say that I prefer chloroform so long as it is administered by a skilled anæsthetist.

In any case, it is advisable to have oxygen ready to hand.

=The position of the patient.= Special tables have been invented and special positions advised. Thus, the dental-chair position is recommended for operations on the Gasserian ganglion, and, in cerebellar operations, it is urged that the patient should be turned on his face, the forehead resting on a tripod, the shoulders on supports fastened to the head of the table. Personally, I do not consider that any special arrangements are required in the majority of cases. Much can be done with sand-bags and firm pillows. Even in the exposure of one cerebellar hemisphere I prefer to utilize the semi-prone position.

In bilateral cerebellar exposure, however, the patient must be placed on his face, the forehead resting on special supports, and the shoulders on props or pillows so as to allow of free entry of air into the chest. In such cases the anæsthetic is administered from below.

I am not enthusiastic over the so-called dental-chair position, but the operating table should be constructed in such a manner that the head and shoulders of the patient can be well raised, the body being inclined to the floor at an angle of about 30-40 degrees.

=Preparation of the operative field.= When the patient is fully under the anæsthetic, the final cleansing of the scalp is carried out and the operative field cut off from all possible sources of infection. In the States, in Cushing’s clinic, the anæsthetist is completely covered with a large sterilized sheet, which is fastened to the head of the patient. In this country we prefer that our anæsthetist should have full knowledge of the progress of the operation, and I think that the advantages are with us. In any case, the whole head is enveloped in gauze, two or three layers thick and about 18 inches square. This sheet is thrown over the patient’s head and maintained in position by means of the scalp-tourniquet (see pp. 14, 15). Around this sterilized towels are arranged, either fastened to one another or stitched to the scalp. When the operation is conducted in the temporal region the towels, unless fastened to the skin by means of a few sutures or safety-pins, tend to become displaced, and by so doing add to the risk of wound infection.

THE CONTROL OF HÆMORRHAGE

=Hæmorrhage from vessels of the scalp.= All surgeons must have appreciated the difficulty attendant on the application of forceps to, and the ligature of, divided scalp-vessels. The patient may lose a considerable quantity of blood, and much valuable time will be wasted before the more essential part of the operation is commenced. All this can, under ordinary circumstances, be avoided by the use of the scalp-tourniquet. As used by Cushing it consists of a rubber ring fashioned after the style of an Esmarch’s tourniquet, encircling the head and passing from the lower frontal region in front, above the ears, to the lower occipital region behind. A median tape, passing from glabella to occiput, prevents any tendency for the tourniquet to slip down over the eyes, at the same time acting as a convenient landmark for the superior longitudinal sinus.

The tourniquet, when applied with the correct pressure, should, under ordinary circumstances, completely control all hæmorrhage from the divided scalp-vessels. It should be noted, however, that bleeding will be rather increased than otherwise if the tourniquet be so loosely applied as to impede the venous return without compressing the scalp arteries. A little experience will soon enable the operator to gauge the requisite pressure.

There is one other exception to the satisfactory working of the scalp-tourniquet. In the presence of a superficial cerebral tumour, especially when of a malignant nature, the normal communication between the intra- and extra-cranial vascular systems may be so exaggerated that those scalp-vessels which receive diploic and emissary venous communications will give rise to some trouble. This difficulty should be overcome--not by rapidity in the formation and turning down of the flap--but by clipping each vessel as exposed or divided, by the application of pressure and by foraminal occlusion (see also p. 17).

I found Cushing’s tourniquet rather inconvenient in its application, and, after various modifications, am accustomed to use the one depicted in the illustration. It consists of two flat metal bands connected posteriorly by a strong rubber connecting link, the two bands passing in front through a metal fixation piece possessing a screw which, when tightened up, allows of the maintenance of the desired pressure. The median tape, previously mentioned, helps to keep the tourniquet in position.

The tourniquet is applied as follows: the whole head is enveloped in gauze--two or three layers thick, and cut to the size and shape of a large handkerchief. The tourniquet is slipped over the head, as low down as possible, and then tightened up. The median tape, having a loop behind through which the tourniquet passes, is laid in the middle line and tied round the screw on the fixation piece.

The gauze should then be moistened with saline solution or some mild antiseptic, so that it clings tightly to the underlying scalp and becomes sufficiently translucent to allow of the recognition of any underlying landmarks that may have been previously mapped out with the scalpel, iodine, silver nitrate, or aniline pencil.

The scalp-flap is then framed by incisions carried down to the bone, through gauze and scalp, in one sweep. The flap is turned down and covered with gauze. By the adoption of this method hæmorrhage from scalp-vessels is efficiently controlled and the risk of wound infection is reduced to a minimum.

After the completion of the operation, the scalp-flap is approximated and sewn into position, first by numerous buried fine silk sutures bringing together the aponeurotic layer of the scalp, and finally by a few silk or salmon-gut sutures passed through the skin itself. Gauze dressings are applied, the tourniquet loosened, and a roll-gauze bandage quickly applied circumferentially around the head, low down over the forehead and occipital region. This roll bandage in reality takes the place of the tourniquet, but is, of course, applied with moderate pressure only.

If the wool and bandage now applied over all should include the ears, these two organs should be well covered with vaseline. Few things are more uncomfortable to the patient than the contact of wool and bandage to the ears.

The tourniquet should be utilized whenever possible. In operations, however, that are conducted near the base of the skull--subtemporal decompression, cerebellar exploration, &c.--the surgeon, in his effort at hæmostasis, must rely on the application of digital pressure on either side of the incision, the more careful exposure of the vessels, and the application of forceps as soon as they are seen or divided, or by the utilization of Vorschütz’s hæmostatic safety-pins.

Other methods of controlling scalp-bleeding are as follows:--

1. Kredel’s hæmostatic sutures, passed with a large curved needle which slides along the bone and emerges about 5 to 7 cm. from the point of introduction. The silk ligatures are then tied over metal plates, so curved as to lie flush with the surface of the skull in the particular region involved. Four of these plates would be used in the formation of an osteoplastic flap, one on the distal side of each of the three scalp incisions, and one along the base of the flap.

2. The enclosure of the proposed incision by a running suture which, passing down to the bone, emerges about 1 inch further on, then so to speak repeating itself in part until the whole region is surrounded. The ligatures are then tightened up. This method takes some time in its application, and presents no advantages over the scalp-tourniquet.

3. The blocking of the main arterial supply--temporal, occipital, and supra-orbital vessels--by modified safety-pins, mass ligatures, &c. Arterial compression by means of the modified safety-pin as suggested by Vorschütz will be found most useful in those operations in which the scalp-tourniquet cannot be utilized--subtemporal decompression, &c.

=Hæmorrhage from the bone.= Severe bleeding may take place from the mastoid and other emissary veins, and from the open mouths of those abnormally dilated diploic and emissary veins so often encountered in the exposure of an underlying dural or superficial cerebral tumour. The foramina in the bone, when exposed, must be occluded as quickly as possible. For this purpose we have the following methods at our disposal--plugging with small bone or wooden pegs, blockage with minute plugs of cotton-wool, and the utilization of Horsley’s wax, smeared over the part and well pressed home.

Hæmorrhage may also occur from the bone during trephining, more especially when the operation is conducted over that part of the anterior division of the middle meningeal artery which runs through a channel in the spheno-parietal region. Here the disk of bone should be removed as quickly as possible and the channel plugged with pegs, cotton-wool, or wax.

Oozing from the raw surface of the cut bone is controlled by rubbing in aseptic wax, or by the crushing together of the inner and outer tables.

=Hæmorrhage from the dural vessels.= In this case the bleeding may occur from three sources, meningeal veins--often of considerable size when related to neighbouring tumour-formation--the middle meningeal artery, and the venous sinuses of the brain.

Hæmorrhage from meningeal veins may be arrested by one or other of the following methods:--

1. Gentle pressure as applied either by dry gauze, or wet gauze soaked in saline solution at a temperature between 110 and 115 degrees Fahrenheit.

2. The application of a piece of muscle to the bleeding-point. This method was, I believe, first introduced by Sir Victor Horsley. Some muscle is usually available for the purpose, usually the temporal muscle. A small portion of muscle is snipped off, spread out as a flat muscular pad, the bleeding area dried, and the graft quickly applied. It soon adheres, and usually arrests the hæmorrhage.

3. The application of a ligature. This method is placed last, being the most difficult. It is usually necessary to underrun the bleeding-point with a fine needle threaded with the finest of silk. It presents the disadvantage in that the needle may perforate the dura mater and puncture one of the superficial cerebral veins.

Hæmorrhage from the middle meningeal artery may be controlled by ligature or torsion, and added to these methods we have one other, recently introduced by Cushing--silver wire ‘clips’. These clips are U-shaped, loaded on a magazine, picked up as required in the jaws of a specially indented forceps, and clipped on to the vessel--usually one on either side of the bleeding-point.

Hæmorrhage from venous sinuses is dealt with on p. 150.

=Hæmorrhage from the superficial vessels of the brain.= This form of hæmorrhage, one of the most troublesome complications arising in head-operations, most commonly results from hasty or careless opening of the dura mater. Thus, when the dura is incised in a case of greatly increased intracranial pressure, the brain herniates suddenly outwards, and the incautious use of the knife will damage one of the dilated superficial cortical veins. The dura should always be opened with the greatest care, the knife being passed lightly over the membrane till the pia-arachnoid is exposed, when the dural margins are lifted up with small tenaculum forceps and the membrane slit up with blunt-pointed scissors or on a grooved director.

In the event of injury, the bleeding may often be controlled by light pressure with dry gauze, or wet gauze wrung out in hot saline solution as described above. If this fails, a very fine silk ligature may be passed beneath the vessel on either side of the site of bleeding. This procedure is not easy to accomplish, the tissues are so soft and friable. However, every effort must be made to arrest the bleeding, for not only does the hæmorrhage obscure the field of operation, but the presence of a blood-clot beneath the dura mater will lead at a later date to the formation of adhesions between the various membranes of the brain--a potent cause of headache, epilepsy, &c.

THE OPENING OF THE SKULL

Two methods are adopted in the exposure of meninges and brain--craniectomy and craniotomy.

=Craniectomy= implies the formation of a scalp-flap, exposure of the bone, trephining of the skull, and enlargement of the gap to the required size and shape.

=Craniotomy= implies the formation of a flap of scalp and bone in one, and the exposure of an area of dura and brain directly proportionate to the size of the bone-flap.

=Craniectomy.= After the application of protective gauze and tourniquet, the scalp-flap is framed according to the requirements of the case. If the tourniquet is used, the knife is entered at one extremity of the proposed flap, carried down to the bone--through gauze and scalp in one--and the incision completed in a single sweep. Under other circumstances, digital pressure is applied to the main flap-supplying vessel, e.g. the temporal artery over the base of the zygoma, or else Kredel’s clamps or Vorschütz’s hæmostatic safety-pins are passed in such a manner as to control bleeding from the main supplying vessel. In the event of bleeding, the surgeon goes along quietly, deepening his incision and seizing each vessel as exposed.

In turning down the scalp-flap it is usually recommended that the pericranium should be included. This is quite unnecessary, and, under certain circumstances, should certainly be omitted (see p. 129). It should be stripped away from the underlying bone as required.

The trephining may be carried out with the hand-trephine, or by means of saws, burrs, and trephines driven by electricity. With the exception of a few words on Hudson’s trephine, I do not propose to discuss the relative advantages and disadvantages of these mechanically-driven instruments. I hold the opinion that the hand-driven instrument is sufficiently rapid in its work, that it is infinitely safer, and that the surgeon should accustom and perfect himself with those instruments which are to him most convenient and most portable. He will not always be conducting his operations in a perfectly equipped hospital, much of his work will be carried out in the nursing home or in the country. Whatever method be adopted, the operator should use those instruments to which he is most accustomed.

Hudson’s trephine is shaped after the style of the carpenter’s brace and is fitted with three cutting heads--the perforator, the follower, and the enlarging burr. It is claimed that injury to the dura and brain is impossible, the instrument becoming automatically locked so soon as the resistance of the internal table is overcome, a thin film of bone being pushed in front of the advancing head. I have had the opportunity of using this instrument, and so far as my experience goes it answers all requirements. Still, I prefer the ordinary hand-trephine so long as it satisfies certain requirements. It must be of simple mechanism and strong, the handle of good size and shaped to fit the hand, the shaft and head so interlocked as to allow of no independent movement, and the hollow head sharply toothed and bevelled externally, in continuity with the teeth, for a distance of half an inch. The bevelling is so arranged that the actual cutting process is only effected during supination of the hand and forearm. The pin of the trephine should not project beyond the cutting edge for a greater distance than about ·2cm. This pin should be readily removable.

The pattern which I am accustomed to use is depicted in Fig. 8. The trephines are kept in three sizes--diameter ¹⁄₂, 1, and 1¹⁄₂ inches. The intermediate size is used for ordinary trephining, the small one for the formation of the osteoplastic flap, the large for the removal of a disk of bone which includes within its circumference the area involved in some depressed and punctured fractures (see p. 133).

FIG. 10.

TO SHOW THE TECHNIQUE OF TREPHINING. Fig. 9 illustrates the act of trephining for cerebellar exposure. Fig. 10 shows a trephine-disk to one side of a depressed fracture.]

The site of trephining may be fixed by the introduction of a bradawl through the scalp, so indenting the external table that the spot can be verified on turning down the scalp-flap. The pin of the trephine is there applied, and the trephine directed at right angles to the surface of the skull, or at that angle which is suited to the region attacked. The pin is discarded when a sufficient groove has been attained. The trephine must be kept under perfect control, muscular effort only being required during the act of supination.

The firm nature of the external table will be readily appreciated; so soon as this resistance is overcome the trephine will be felt to be cutting its way through a softer structure, whilst the increased bone-dust and venous oozing will make it evident that the instrument is biting its way through the diploic tissue. Greater resistance is again encountered on meeting the internal table, warning the operator that the time has come when greater care must be exercised. The bone-dust must be wiped away, the teeth of the trephine cleansed with nail-brush or sponge, and the depth of the groove estimated. The groove should be of the same depth throughout its circumference, or of that depth which is suited to the part involved.

The readiness of the disk for removal is best demonstrated by digital pressure. When it gives to that pressure, whether in whole or in part, the elevator may be applied and the fragment removed.

In the temporal and cerebellar regions special care is required by reason of the absence of diploic tissue.

It is impossible to lay too much stress on the necessity of avoiding injury to underlying dura and meningeal vessels. Injury to these structures not infrequently upsets the whole plan of campaign.

LANE’S FULCRUM CRANIECTOMY FORCEPS.]

HORSLEY’S GOUGE FORCEPS.]

The enlargement of the trephine hole to the required size and shape. Previous to any attempt at enlargement of the trephine hole, the dura mater must be separated from the bone with the aid of Horsley’s dural separator or other suitable instrument. Of the many patterns of craniectomy forceps, the following will be found to suit all requirements:--

Keen-Hoffmann. The visceral blade is introduced between the dura and the bone and ‘morcellement’ carried out. It is essential that the surgeon should not be too greedy, resting content with the removal of small fragments at a time.

Lane’s fulcrum forceps. They possess great mechanical advantage and are mainly suited for the rapid removal of large portions of bone.

Horsley’s nibbling or rongeur forceps. This instrument is mainly utilized in the smoothing and refreshing of sharp edges of bone, and in the ‘morcellement’ of the thinner portions of the skull--temporal and cerebellar regions.

De Vilbiss’s forceps. A clever contrivance whereby the operator is enabled to cut a narrow channel in the bone. Mainly utilized in the formation of the osteoplastic flap.

=Craniotomy.= Craniotomy, or osteoplastic resection of the skull, was first carried out by Wagner. It is proposed to describe that method only which, by experience, has been found to meet all requirements--the formation of the osteoplastic flap by means of the hand-trephine, Gigli’s saw, and de Vilbiss’s forceps.

The protective gauze dressing and scalp-tourniquet are applied as before. A large

______ \ / -shaped \ /

incision is made in such a manner as to include the area which it is desired to expose. The two vertical limbs of the incision should converge to such a degree as to allow of the subsequent ready fracture of the flap along its base. The knife is entered at one extremity, carried down to the bone, and the three incisions rapidly made, one after the other. Along the line of each of the three incisions, the pericranium is stripped away from the bone so as to allow of adequate exposure. At the anterior and posterior angles of the flap the tissues are retracted a little more, permitting the application of a half-inch diameter trephine. Here the two trephine-holes are bored--with the usual precautions against damage to the dura mater--and the two disks of bone elevated and removed.

Between these two trephine-holes the dura mater is separated from the bone and the special director introduced, entering at the one hole, emerging at the other, and lying throughout between the dura and the bone. The saw is now passed along the groove of the director, the handles affixed, and the bone intervening between the two trephine-holes divided, not straight out to the surface, but bevelled or cut in such an oblique manner that the bone-flap, when replaced, rests on a ledge (see Figs. 17-19). The sawing process generates considerable heat, and the assistant should be instructed to keep up irrigation with saline solution or sterilized water. The sawing is carried out by steady side-to-side traction, without jerks; if the saw breaks, the special handle may be attached, thus obviating the necessity of introducing a new saw.

The dura is now separated from the bone along the line of the two vertical incisions, and the visceral blade of de Vilbiss’s forceps insinuated beneath the bone, starting at one trephine-hole and working downwards to the lower limit of the incision. It is essential that the operator should be satisfied with the ‘morcellement’ of small portions of bone at each bite of the instrument. At the lower end of each of the vertical incisions the forceps is directed inwards for ¹⁄₄ to ¹⁄₂ inch so as to weaken the base of the flap.

To lift up the osteoplastic flap, a stout elevator or spatula is introduced beneath the bone at its upper part, leverage applied, and, as soon as sufficient elevation has been attained, the dura mater carefully separated from the whole of the under aspect of the flap. The flap is then grasped at its upper part with both hands and, with a quick but forcible jerk, broken across at its base, the assistant at the same time aiding the correct linear fracture of the bone by a flat spatula applied to the outer aspect of the base of the flap. Insomuch as the flap is most usually framed in the parieto-temporal region--for the exposure of the motor area--the base of the flap, being formed from the squamous portion of the temporal bone, is comparatively weak. Fracture is then readily obtained. Under other circumstances the base may be sufficiently weakened by the application of the de Vilbiss forceps or by the use of the Gigli saw.

The bone-flap is thrown back and enveloped in gauze. Its basal region is examined for a possible injury to meningeal vessels. In the event of such complications the bleeding vessel is clipped, ligatured, or underrun. Possibly some branch of the anterior division of the middle meningeal artery, running in an osseous canal, may require to be controlled by foraminal occlusion--with a wooden match, bone peg, cotton-wool, or aseptic wax.

In comparing the =relative advantages and disadvantages= of craniectomy and craniotomy, although there are certain definite contra-indications to the latter method, yet craniotomy should always be carried out when the surgeon desires to expose a large surface area of brain, more especially in the exposure of a tumour diagnosed to lie in relation to the motor cortex. Even if the operator should be unsuccessful in his exploration, or, if finding the tumour, should deem it irremovable, the dura can be sewn up and the bone-flap replaced, resting on its bevelled edge, with little defect in the skull and a normal surface contour.

The three main disadvantages to craniotomy are as follows:--(1) the operation can seldom be done under much less than thirty minutes; (2) there is some slight risk of complication through injury to the middle meningeal artery; and (3) the dura mater may be so adherent to the bone as to be torn in the process of flap-elevation. Time, however, is usually of little importance; bleeding from the middle meningeal artery may be controlled, and dural lesions may be avoided by careful technique. In general, the advantages of osteoplastic resection greatly outweigh the disadvantages.

The more definite contra-indications to the formation of the bone-flap are as follows:--

1. This operation is unnecessarily severe in most cases of intracranial hæmorrhage, e. g. from the middle meningeal artery. It is also usually impracticable by reason of the associated damage to the bones of the vault and base.

2. It is contra-indicated in operations conducted for the exposure of the Gasserian ganglion, its root and its branches (trigeminal neuralgia). In these operations it is essential that the operator should get down as low as possible towards the base of the skull.

3. It is contra-indicated in operations conducted in the cerebellar region. Even after cerebellar exposure by craniectomy, the surgeon is working in a sufficiently confined space. The presence of a bone-flap only adds further difficulty and complication. Added to this is the fact that the thin wall of the cerebellar fossa is not adapted to osteoplastic flap-formation.

=Opening the dura mater.= Reference has already been made to the great importance of opening the dura in such a manner as to avoid injury to the underlying superficial cerebral vessels (see p. 19). It may be incised in a crucial manner or by flap-formation. Flaps are usually to be preferred if the surgeon desires to have the widest possible view of the brain surface. In the formation of the flap, advantage should be taken of the vessels that minister to its vitality. Thus, in the lateral region of the head, the base lies below, the middle meningeal artery supplying the flap. Under special circumstances, the blood-supply may be disregarded; the flap never sloughs, so far as my experience goes.

=Sewing up the dura mater.= Considerable difficulty may be experienced in sewing up the dura--by reason of the bulging of the brain. How these difficulties may be overcome is dealt with on p. 236. The edges should be united by numerous fine silk sutures.

=Replacement of the osteoplastic flap and sewing up.= The flap is replaced, care being taken that its lower or fractured edge does not injure the dura mater. The aponeurotic and subcutaneous tissues of the scalp-flap are sewn up in the manner stated on p. 16.

=After-treatment.= Whether the operation be carried out by craniectomy or craniotomy, the patient is put back to bed in the so-called head-down position, the lower end of the bed being raised at least a foot above the level of the head. In the event of shock, a hypodermic injection of a ¹⁄₄ gr. of morphia should be given, the lower extremities may be bandaged firmly from below upwards, and saline infusions administered, preferably per rectum.