Gun-shot wounds of the scalp are usually associated with damage to the skull and brain. A spent shot, however, may pierce the scalp, and then, glancing off the bone, lodge in the soft parts.
Complete Avulsion.—In women, the scalp is sometimes torn from the cranium as a result of the hair being caught in revolving machinery. The portion removed, as a rule, consists of integument and aponeurosis with portions of muscle attached. In a few cases the pericranium also has been torn away. So long as any attachment to the intact scalp remains, the parts should be replaced, and, if asepsis is maintained, a satisfactory result may be hoped for. When the scalp is entirely separated, recourse must be had to skin-grafting.
Treatment of recent Scalp Wounds.—To ensure asepsis, the hair should be shaved from the area around the wound, and the part then purified. Gross dirt ground into the edges of lacerated wounds is best removed by paring with scissors. Undermined flaps must be further opened up and drained—by counter-openings if necessary. When there is reason to suspect their presence, foreign bodies should be sought for. Bleeding is arrested by forci-pressure or by ligature; when, as is often the case, these measures fail, the hæmorrhage may be controlled by passing a needle threaded with catgut through the scalp so as to include the bleeding vessel. The wound is stitched with horse-hair or silk, and, except in very small and superficial wounds, it is best to allow for drainage. With the use of iodine as a disinfectant, it is often advantageous to dispense with dressings altogether.
Complications of Scalp Wounds.—The most common complications are those due to infection, which not only aggravates the local condition, but is apt to lead to spreading cellulitis, osteomyelitis, meningitis, or inflammation of the intra-cranial sinuses. These dangerous sequelæ are liable to follow infection of any scalp wound, but more especially such as implicate the sub-aponeurotic area, or the pericranium. In the integument, a small localised abscess, attended with pain and œdema of surrounding parts, may form. Pus forming under the aponeurosis is liable to spread widely, pointing above the eyebrow, in the occipital region, or in the line of the zygoma. Suppuration under the pericranium tends to be limited by the inter-sutural attachments of the membrane. Necrosis of the outer table, or even of the whole thickness of the skull, may follow, although it is by no means uncommon for large denuded areas of bone to retain their vitality.
The onset of infection is indicated by restlessness, throbbing pain and heat in the wound, a feeling of chilliness or the occurrence of a rigor, and tension of the stitches from œdema of the surrounding tissues. The œdema often extends to the eyelids and face; a puffiness of the eyelids, indeed, is not infrequently the first evidence of the occurrence of infection in the wound.
Treatment.—When suppuration ensues, the stitches should be removed, the wound opened up and purified with eusol, and packed. A dressing of ichthyol and glycerine should be employed for a few days.
Erysipelas of the scalp may originate even in wounds so trivial as to be almost invisible, or from suppurative processes in the region of the frontal sinuses or nasal fossæ. It tends to be limited by the attachments of deep fasciæ, and seldom spreads to the cheek or neck. Symptoms of cerebral complications, in the form of delirium or coma, and of meningitis may supervene. Cellulitis beneath the aponeurosis from mixed infection is a dangerous complication.
Diseases of the Scalp
Infective Conditions.—It is not uncommon for localised abscesses to occur in the subcutaneous cellular tissue in delicate children, and such collections are not infrequently associated with pediculi, impetigo, or chronic dermatitis. They develop slowly and painlessly, and are only covered by a thin, bluish pellicle of skin. It is not improbable that they result from a mixed infection by pyogenic and tuberculous organisms. As a rule they heal quickly after incision and drainage, but when they are allowed to burst, tedious superficial ulcers may form. Localised abscesses may also form in connection with disease of the cranial bones. Suppuration following upon injuries has already been referred to.
Boils and carbuncles are not common on the hairy part of the scalp. Lupus rarely originates on the scalp, although it may spread thither from the face. Syphilitic lesions are common and present the same characters as elsewhere. Gummata may develop in the soft parts, but more commonly they take origin in the pericranium or bone. Eczema capitis is of surgical importance only in so far as it often forms the starting-point of infection of lymph glands by pyogenic and other organisms.