These new pages 475-549 are to be inserted in place of the old pages 475-549, Volume I, Tice's Practice of Medicine.

FIG. 9.-LUMBAR PUNCTURE: WITHDRAWAL OF FLUID.

Needle in position. Manometer withdrawn; stylet inserted slightly to close this aperture, and fluid issuing into test tube from aperture from which stopper on chain has been removed.

FIG. 10.-LUMBAR PUNCTURE: INTRASPINAL INJECTIONS BY GRAVITY METHOD, SHOW

are desired, the manometer is attached as soon as the needle enters the canal and before the stylet is withdrawn, the readings made, and the fluid in the manometer used for the examination. Where fluid is to be removed for therapeutic purposes or if the fluid is under greatly increased pressure, it is unwise to reduce the pressure below 100-120 mm. of water or 10-12 mm. of mercury. In using the needle to gauge the pressure for this purpose the fluid should be permitted to flow until it issues slowly drop by drop from the needle. When the pressure is high the fluid will issue in a spurt or steady stream if the point of the

needle is free in the canal and unimpeded. It is of the greatest importance for the novice to be mindful of the danger of too sudden or rapid withdrawal of fluid in certain intracranial conditions, and in every new case so to regulate the flow of the fluid from the needle by means of partial withdrawal of the stylet from the hub of the needle, or by use of a pressure apparatus, that pressure will be reduced slowly. The Queckenstedt Phenomenon.-Pressure on the jugular veins causes increased intracranial pressure, which can be recorded by means of the spinal manometer and can be charted graphically. Pressure on the jugulars by the finger or by a specially prepared band increases the pressure in the lumbar sac, which in turn increases the column of fluid in the manometer. Failure to cause this rise is indicative of a block somewhere between the cranial cavity and the site of puncture. This phenomenon was first used diagnostically by Queckenstedt.

These new pages 475-549 are to be inserted in place of the old pages 475-549, Volume I, Tice's Practice of Medicine.

Complete block is easily demonstrated by a failure of the fluid to rise promptly in the manometer, but in incomplete block there may be a definite rise, perhaps less promptly, with a hesitating and interrupted fall of the column of fluid as pressure is released on the jugulars. In cases where there is no block, even a slight touch of the jugular often causes a characteristic rise and prompt decline when pressure is released. Often in cases of block, jugular compression may be unproductive of a rise, but coughing or straining may cause a rise, due to increase of pressure in the intraspinal chamber.

Amount to Be Withdrawn. For ordinary diagnostic procedures. withdrawal of 3-5 c.c. is sufficient. If in cases of meningitis the fluid is clear and tuberculosis is suspected, from 5-10 c.c. or more may be removed to facilitate the search for tubercle bacilli. In luetic individuals where the puncture is done for diagnostic corroboration in an individual not suspected of having involvement of the nervous system, it is wise to remove as little fluid as possible in order to avoid aftereffects. Although individuals with involvement of the nervous system occasionally suffer from this, it seems that normal patients suffer more and oftenest, while paretics infrequently complain of after-pains. Occasionally lightning pains in tabetics are aggravated for a short time. after the withdrawal of fluid, or a crisis may even-though rarely-be provoked. In all these cases 2-3 c.c. of fluid will suffice for all diagnostic purposes. Replacement by saline has not proven of any value in the writer's experience. A safe guide in most cases is not to remove more than the amount indicated unless the fluid is under increased pressure, in which event it may be allowed to flow until pressure is reduced almost but not quite to normal, say to 150-130 mm. of water. After-treatment.-To prevent entirely or mitigate the painful sequelæ of lumbar puncture, rest in bed after the puncture is essential. The foot of the bed may be raised a foot, in case tumor of the posterior fossa is suspected. It is unwise and even dangerous to do the puncture as a routine procedure at one's office or at the clinic and allow the patient to go home. The patient should be kept in bed after the puncture, flat on his back for at least 1-2 hours, and may then be permitted to have a small pillow under his head. Quiet and repose should be enforced. In nervous and irritable individuals, especially in tabetics with lightning pains, a dose of codeine, grain 1⁄2-1 (0.032-0.065 gram), or morphine sulfate, grain -4 (0.008-0.016 gram), with atropine, grain 1/150, may be given hypodermically. In very severe cases grain 1/100 of hyoscine may be necessary. In such agitated cases it is often wise to precede the puncture by sedative treatment. If the patient, on a previous puncture, suffered from after-effects, it is better to give an opiate before performing the puncture, and again after its completion. Most patients should be kept in bed for from 12-24 hours and then allowed to sit up gradually before arising. Sometimes the aftereffects do not come on for 24-48 hours after puncture, in which event, if severe, rest in bed with an ice-cap to the head and a dose of codeine, is advisable. If the pain is slight a dose of pyramidon, 3 grains (0.195 gram), or acetylsalicylic acid, 5-10 grains (0.324-0.65 gram), or acetphenetidine, 5 grains (0.324 gram), by mouth, often suffices to control it. The writer has tried injections of pituitrin without beneficial results. If the pains persist when the patient is in the upright position, a reclining position with medication, as advised above, is indicated.

The pain usually disappears immediately when the patient lies down. The sequelæ infrequently last longer than a few days to a week, although if the patient persists in walking about, severe headache may last as long as two weeks.

During and for at least one-half hour after the removal of spinal fluid, an assistant or nurse should watch the patient carefully, especially where tumor of the brain is suspected-observing his color, pulse and respirations. A marked change in pulse or respirations, a sudden, severe headache or feeling of nausea, should immediately call for a halt in the removal of fluid, and if the pulse or respiration do not become regular and normal, or if cyanosis supervenes, stimulation and artificial respiration should at once be resorted to and kept up until the patient is again breathing normally.

Lumbar Puncture under Anesthesia.-In the vast majority of instances spinal puncture can be performed without the use of any anesthetic, local or general. In hypersensitive individuals local anesthesia may be used and a spray of ethyl chloride at the puncture site will usually suffice. Some operators prefer the use of infiltration anesthesia with cocaine or other local anesthetic. The writer prefers novococaine 1 per cent. for this purpose. The skin at the site of puncture is first infiltrated with a few drops of the solution, a two-inch needle of about 19-20 gauge (B & S) is then pushed through this area as far as it goes without piercing the membranes, and about 2-3 c.c. of 1 per cent. novococaine solution infiltrated, while the needle is slowly being withdrawn or as it is pushed in. After five minutes the spinal puncture can be performed painlessly. Children rarely need an anesthetic. The writer never uses it for them. In delirium or maniacal patients a general anesthetic may be necessary, a few whiffs of chloroform being given—just enough to quiet the individual. The more expert the operator, the less frequently will he resort to the use of any form of anesthesia for this procedure. Infiltration with an anesthetic has one disadvantage, in that it tends to obscure somewhat the landmarks. Under these circumstances it is wise to leave the infiltrating needle in situ and pass the lumbar puncture needle along it, using it as a guide or director.

After the needle is withdrawn the site of puncture is cleansed of its iodine coating with alcohol, dried, and a small protective dressing placed over the puncture hole.

Lumbar Puncture Headache. Of the minor sequelæ of lumbar puncture, the most common as well as the most distressing to the patient is the headache which follows this procedure. It is frontal, temporal or occipital, or feels like a tight constricting band around the head, and is often throbbing and intense. If the patient persists in walking about or even in sitting up, nausea or projectile vomiting may occur. There may be faintness or weakness. Lying down promptly relieves pain and concomitant symptoms.

The cause of lumbar puncture headache is very much in doubt. It is believed that it occurs more frequently when the spinal fluid is negative than when it is positive. In other words, many believe individuals without involvement of the neuraxis, e.g., cured luetics, submitting to puncture for diagnosis are more apt to suffer than those with a definite lesion of the central nervous system. In the writer's experience this is probably not the case as patients with syphilis of the nervous system and positive spinal fluid tests suffer as much and almost as

These new pages 475-549 are to be inserted in place of the old pages 475-549, Volume I, Tice's Practice of Medicine.

frequently as normal individuals. An exception to this must be made. for paretic individuals, who rarely suffer after-effects. The explanation may be in the fact that in paretics the fluid is under considerable increase of pressure, and puncture relieves this without reducing it sufficiently to bring on headache. In other individuals with marked increase of intracranial pressure, puncture promptly relieves headache due to this factor.

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The headache is said to be more frequent following puncture in the sitting position or where this position is assumed within twenty-four hours after puncture; but in many patients who are kept in bed twentyfour hours after puncture the pain is not averted, though in the writer's experience it is less frequent. The amount of fluid removed is probably not a factor unless too large a quantity is withdrawn, for the removal of a few drops has been followed by a typical headache lasting a week whenever the patient assumed the upright position; and the immediate replacement of the fluid withdrawn by saline solution has had no effect in averting it. In certain cases of loss of spinal fluid through the nasal cavity or following fracture of the bone of the skull, as much as 600 c.c. has been known to be drained off within twenty-four hours without ill effect, but the patients were usually in the reclining position. This also applies to cases undergoing ventricular or cisternal puncture and following decompressive and other brain procedures where fluid is lost. According to Dana, the headache is caused by irritation of the dural fibers of the 5th and occipital nerves when the fluid is drained away, allowing the brain to sink down on the bone. There is an acute disturbance of the mechanics of the cerebrospinal circulation. But this explanation will hardly suffice for the many instances of headache following the withdrawal of less than 5 c.c. of fluid. The explanation of MacRoberts is very ingenious and plausible. He points out that the pia closely invests the cord while the fluid is in the subarachnoid space between the pia and the arachnoid and dura, which are in close apposition. The latter is tough and firm and fibrous, the arachnoid, loose and full and nonvascular. The needle pierces the tough dura, makes a hole in it which may persist after the needle is withdrawn, unless the loose arachnoid plugs it up. If the arachnoid is sucked into the hole by the needle in its outward excursion, it forms a wick or funnel facilitating the seepage of cerebrospinal fluid out of the canal into the epidural space. MacRobert cites a case of headache following interruption of a puncture after the needle had entered the dural sac but before any fluid was withdrawn. The constant leakage into the epidural space causes the cushion of fluid at the base of the brain to be lost, and when the patient sits up the entire weight of the brain is impacted through the pons to the basilar plexus of veins on the clivus of the occipital bone. The veins are soft and compressible in contradistinction to the sinuses in the skull, which are tough and not readily compressible. The venous flow is impeded in its passage through the compressed vessels and is forced to travel by other crowded pathways, with a rise of venous pressure and a coincidental rise in intracranial pressure. When the patient lies down the weight is lifted off these vessels, circulation is restored and the headache is relieved. The healing of the small hole in the dura in a few days or a week allows the fluid to re-accumulate, restores the water cushion at the base of the brain, and so adjusts the mechanism of the cerebrospinal pressure and circulation as to remove the cause of