Injuries to the nervous system

Injuries to the nervous systemInjuries to the nervous system may involve any part to any extent. It is of great import that de­stroyed tissue of the brain and spinal cord will not regenerate; peripheral nerves will. In many cases of accident concurrent injuries to other parts complicate the treatment of nervous sys­tem injuries. With the ever-increasing number of automobile accidents, injuries to the nervous system are progressively more prevalent.

Scalp injuries are mentioned here, even though the scalp is not a part of the nervous sys­tem, because it is almost always affected in head injuries which involve the brain.

Lacerations of the scalp are treated essen­tially in the same way as skin lacerations in other areas. There may be more profuse bleeding, how­ever, since the scalp has an abundant blood sup­ply. Infections may be more prevalent since the hair-covered scalp is more abundant with germs. When the laceration is limited to the scalp, simple repair under sterile conditions may be done with local anesthesia. Lacerations with loss of scalp portions may require flap or rotation grafting. Some scalp lacerations involve imbedded foreign material; these are removed at the time of re­pair. Contusions of the scalp, or bleeding within and beneath it, will usually absorb with­out active treatment, but care must be taken against infection. In all cases of scalp injury definite investigation for concurrent injury to the brain is mandatory.

Skull fractures

Skull fractures are frequently associated with brain damage. The skull is not a part of the nervous system, but its close relationship to the brain in head injuries demands its inclusion in the study of brain injury. The only value of the skull is as a rigid protective container for the brain; i.e., fractures do not have the same im­plications as do fractures of weight-bearing bones. However, they may be of more serious import because of the damage sustained to the brain.

The skull and its contents has been compared to an egg. The shell may be radically fractured without damage to the yolk; on the other hand, it may be so shaken or jarred that the contents become scrambled without shell fracture. This is to say, there is little relationship between the amount of damage to the bony shell of the skull and the underlying brain damage. In all cases of skull fracture the extent of underlying brain damage must be ascertained.

Skull fractures are caused most commonly by blunt blows on the head. Gunshot wounds and other piercing injuries may also produce frac­ture. In the latter instances brain damage is al­ways concomitant.

Skull fractures may be in any area of any magnitude or design. The linear fracture is merely a straight line crack in a bone. The stellate (“star”) fracture is a series of cracks in the flat bone radiating out from a cen­tral point. Depressed skull fractures are those where a portion of bone is driven in to press against the brain. These almost always demand operative intervention to elevate the fragments and relieve the pressure on the brain.

Compound fractures of the skull are those where both bone and brain are exposed by tear in the scalp. These often occur from flying debris and bullets. Pieces of shrapnel, hair, bone, and dirt may be driven into the brain. Treat­ment, of course, is operative for the removal of the foreign materials and repair of the tissues.

In the operative repair of skull fractures where there is loss of covering tissue, artificial materials are sometimes employed to cover the defect. Metal screens and plates may be used for missing bone parts, or fascia grafts for dura defects.

Brain concussion is the injury caused by a violent blow on the head with jarring of the brain. There may be an actual bruising of the brain or merely swelling. It is attended by the loss of consciousness which may be of a few seconds’ to several days’ duration. There may or may not be associated scalp and skull injuries. Treatment is by medical measures to minimize the brain’s swelling within its rigid vault and to support the patient’s vital functions of respira­tion and circulation. Often other injuries are also present, but the concussion usually warrants primary care.

Brain hemorrhage

Brain hemorrhage may occur with bleed­ing into the brain tissue or bleeding into the spaces around it. This occupies space which crowds and compresses the brain. Often there is an associated skull fracture. According to the positions, hemorrhage around the brain may be classed as extradural or subdural hemor­rhage, the former being outside the dura mater and the latter beneath it.

Extradural hemorrhage occurs most fre­quently at the side of the head by tearing of an artery. This develops rapidly as the blood ac­cumulates between the skull and the dura, to press the dura inward against the brain. Treat­ment is by operation as soon as possible. Cra­niotomy on the involved side is accomplished by making a burr hole through the cranium; the clot is removed, the bleeding areas arrested, and the wound closed. Drains are usually not used. The bone defect may be covered or allowed to regenerate. Postoperative care must be diligent.

Subdural hemorrhage usually develops more gradually since the bleeding source is from ruptured veins. The clot develops slowly and further enlarges as fluid accumulates within it. The first symptoms may appear days or weeks after an injury. The hemorrhage is usually toward the top of the brain and in about half the cases it occurs over both hemispheres. Treatment is by craniotomy opening over the dome of the skull with incision through the dura. The blood clot is evacuated, bleeding points halted, and the dura closed. Drains are usually not employed. The craniotomy opening may or may not be covered before the scalp is closed. Recovery is usually complete if the operation is performed before permanent brain damage from the pressure of the clot has occurred.

Intracerebral hemorrhage is the case of bleeding into the brain substance itself. The clot is pooled inside the semisolid cerebral substance. This may develop rapidly or slowly after injury. Treatment for this condition rests with crani­otomy by opening through the scalp, cranium, and dura; a needle is then inserted through the brain tissue into the hemorrhage. The blood is withdrawn through the needle and the cavity irri­gated with a solution. This usually effects a cure, but the results are not quite so favorable as with other types of brain hemorrhage.

Hygroma is a collection of entrapped cerebro­spinal fluid in an area over the surface of the brain. It develops from a tear of the arachnoid by injury. The fluid becomes trapped in the space between the brain and the dura. Treatment is essentially the same as for subdural hemorrhage.

Spinal injuries

Spinal injuries may involve damage to the bony spinal column or to the spinal cord or to both.

Spinal column (vertebral) injuries are of greatest concern when there is concomitant spinal cord injury. Fractures will regenerate; the spinal cord will not. With any injury of the spine the possibility of cord damage must be given serious consideration in all aspects of treatment. First aid care is of extreme importance as move­ments of a spine which has been fractured or dislocated may produce further cord damage.

Great care must be exercised in moving such a patient onto a stretcher, in transportation to a hospital, in examination, in positioning for x-ray pictures, and in treatment procedures.

In general, when the injury involves the upper (cervical) portion of the spinal column, it is best to maintain traction on the head at all times, i.e., pulling the head upward away from the shoulders. This may be accomplished by an attendant at the patient’s head placing his hands on the sides of the head and exerting a constant pull. In general, when the injury is in the middle or lower segment (thoracic or lumbar), it is best to maintain the trunk in hyperextension, i.e., bowing the abdomen forward and the shoulders and hips backward. This may be accomplished by placing a bulky pillow on the stretcher in the mid-back.

Injuries of the spine may be a fracture (break) of any part or parts of a vertebra, or may be a dislocation of a vertebra out of the normal alignment. When both conditions exist it is called fracture-dislocation. Usually when any part of the spinal canal (neural arch) is frac­tured or dislocated, the spinal cord is damaged.

A common specific type of fracture of a vertebra is the compression fracture. Here the body of the vertebra is smashed together much like hitting a small block of wood with a heavy hammer; it is compressed together but does not fragment. Compression fracture occurs most often at the mid-back level (vertebra T-12 or L-l). The mechanism of injury is by forceful flexion of the spinal column, such as a fall on the buttock. Fractures of a transverse process or spinous process of a vertebra are usually from direct blows to the area and most often result in complete recovery, even without the use of ex­tensive treatment procedures.

Dislocations of the vertebrae are the result of severe injury. They are not thought to occur spontaneously, and certainly they are not so frequent as many of the cultists imply when they advocate treatment by “spinal adjustment.” When there is a dislocation in the spinal column, neuro­logical signs are almost always demonstrable im­mediately after the injury. They can be confirmed by x-ray picture.

Fractures of the cervical spine are caused most often by a blow on top of the head, frequently sustained in diving, auto accidents, and falling objects. After neurological examination and x-ray pictures, the treatment most often indicated is continuous traction on the head. This may be performed by a sling around the chin and back of neck attached to a rope over a pulley at the head of the bed with weights attached. Or, more permanent traction may be employed by the use of head tongs; by minor operation this grasping device is placed into the outer table of bone of the skull and attached to traction by weights.

When fracture-dislocation produces pressure on the cord, operative treatment may be neces­sary. In these instances laminectomy is per­formed and any fragments pressing on the cord are removed or replaced. This is most often necessary in injuries of the cervical region. Whether treatment has been operative or by traction alone, if there has been extensive com­pression of the cervical cord, the neck must be immobilized for rather long periods, on the average of two months of traction in bed fol­lowed by four months in a neck brace.

Fractures or dislocations of the thoracic or lumbar levels very infrequently demand opera­tive treatment. Usually the treatment indicated is by maintaining the back in hyperextension, the back bowed forward at its mid-portion. This may be accomplished by maintaining the posi­tion in bed followed by a body cast, the time of cast application depending on the extent of vertebral damage. Entire treatment usually takes over three months.

Spinal cord injury may be of any magnitude, from a slight jarring to complete severance of the cord. Immediately following injury the extent of damage may not be readily apparent. Im­provement is more often the rule than progression of neurological disorder, as the swelling and bleeding subside. But again it must be mentioned there is no regeneration of permanently injured spinal cord tissue.

Spinal cord injuries caused by a severe jar with bruising or hemorrhage into the cord tis- tue are called spinal cord concussion. With medical measures and rest there is almost always complete recovery. Rarely, open operation for hemorrhage is necessary.

Open wounds which produce spinal cord in­jury may be by stabbing, flying debris, and bullets. These often require operation. Cord in­juries associated with fracture and/or disloca­tion demand simultaneous treatment of both.

The extent of permanent paralysis and sensory loss depends on the tracts in the spinal cord which have been permanently injured. Complete severance of any fiber in the cord renders it for­ever after incapable of transmitting impulses. These may be sensory tracts or motor tracts; they may be for voluntary activity or auto­matic functions; they may be for sensations above or below the level of consciousness. The handicap of a paralyzed or partially paralyzed extremity may be easily realized, but the loss of automatic functions, such as a paralyzed bowel or bladder, may be even more disabling or a greater threat to life. When the vital centers of the brain stem (heart or respiration center) have been injured, death is imminent. With loss of skin sensations, then bums, ulcerations, and pressure sores may develop and progress without the patient’s awareness.

Rehabilitation

Rehabilitation, after maximal treatment and convalescence from brain and spinal cord in­juries, includes all the facilities of physical ther­apy and occupational therapy. In the recent years newer concepts and magnificent ad­vances have been forthcoming in rehabilitation. Needless to say, much perseverance and patience and concerted effort are demanded of the pa­tient to achieve maximal rehabilitation and em­ployability.

Peripheral nerve injuries are not common in civilian life, but in World War II they were quite frequent and great advancement in the techniques of repairs resulted. A nerve may be completely or partially severed, or crushed. The injury may occur at any site but most commonly in the limbs. Gunshot wounds and deep lacera­tions account for many.

The earlier the repair of nerves, the better is the return of function; early repair is imperative. Incisions for approach to the nerve may be at al­most any site on the extremity. The operation for repair entails dissecting out the fragments, removing all dead tissue, and suturing the nerve ends back together. The nerve fibers will then regenerate. In cases where there is loss of a large segment of the nerve, the repair may re­quire nerve transposition—that is, displacing the nerve to a shorter course in the limb. When long segments of nerve tissue are destroyed, nerve implants may be used, but the functional result is not so good as with end-to-end re-union. Further investigation of this problem is cur­rently in progress.

After repair and closure of the incision, im­mobilization by a cast is usually necessary. Re­generation and return of function may take weeks or months.

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