There is a form of nerve injury which is due to the temporary pressure of the elastic tourniquet, frequently applied around limbs previous to operations, or to pressure which is made by crutch handles upon the axillary plexus, and called crutch paralysis. Limbs carelessly allowed to hang over the edge of the operating table during prolonged operations also have suffered in the same way. Such lesions are of the character of a contusion, but are often followed by paresis, paralysis, and by various sensory disturbances.
Injury to a nerve trunk having been recognized by a study of the local features of a given case requires special treatment in case laceration or more localized division can be assumed. The nerve known to be lacerated and torn across should have its ends freshened and be reunited by fine catgut sutures; also a nerve trunk known to be punctured or divided. Such injury is not necessarily inflicted from without, as it may be produced by a fragment of bone; in this case the operation should be directed toward the bone as well as toward the nerve trunk itself. A divided nerve trunk, if neatly sutured, heals by the organization of blood clot, as in other instances, actual nerve communication being made across the intervening clot by a process of regeneration or reduplication of the true nerve elements, the peripheral neurilemma playing an important part. Autogenetic power decreases with the age of the individual. By careful nerve suturing disability may be prevented.
Even months after injury much can be accomplished by nerve suture properly performed. Symptoms similar to those of division may occur when a nerve trunk is surrounded and compressed by bone callus after fracture, as when the ulnar nerve is thus caught. If too long a time have intervened it may be necessary to exsect the injured portion and then bring the ends into apposition by sutures. Other methods of atoning for these nerve injuries by nerve grafting, etc., will be described in the chapter on Surgery of the Peripheral Nerves.
Neuritis may be overcome by counterirritation, preferably with the actual cautery, i. e., the “flying cautery,” by massage, and by galvanization. The pain in many of these cases can be mitigated, if not completely relieved, by the x-rays, or by the high-frequency current. In some cases nerve elongation may be brought to bear and a tender and irritable nerve be thus brought under subjection.
INJURIES TO MUSCLES AND TENDONS.
Lacerations or divisions of muscles are usually repaired at first by fibrous tissue, the result of organization of a clot. Later a true muscle regeneration takes place and muscle scar finally disappears. Atrophy of a muscle is not a sign of injury directly to itself, but often results from injury to the nerve which supplies it; for example, the circumflex nerve may be injured in shoulder dislocations, while the deltoid muscle, which is supplied by it, speedily undergoes atrophy.
Muscle fibers may be torn by violent exertion. Such an accident may be followed by pain and loss of function. An interval can often be felt, even from the outside, between the torn muscle ends. The injury will produce considerable hemorrhage. The amount of function regained in a muscle will depend to some degree on the extent of its injury. If it have been injured by an incised wound it will depend upon the way in which it is brought together after an open incision. The origin and insertion of such a muscle should be approximated by proper position, and so maintained by the dressings, in order that perfect rest may be more easily maintained. When a portion of the fascia or aponeurosis is torn the muscle fiber may protrude and form a hernia of muscle.
Tendons often suffer from contusion, in consequence of which they may become adherent within their tendon sheaths; this leads to stiffness of the part and more or less loss of function. Sometimes they calcify, as does the adductor magnus tendon in the formation of the so-called rider’s bone. The tendon most frequently injured is that of the quadriceps, near the knee.
If it can be decided that a tendon has been divided or torn across its prompt reunion by suture should be always practised. Also a divided muscle, if exposed, should be drawn together with sutures, chromic or hardened, so as to make them more reliable. Tears of aponeuroses and fasciæ should also be sutured. Tendon suturing is nearly always successful, especially if it can be done in a cleanly manner; while tendon grafting is a measure which may be reserved to overcome the consequences of injuries to muscles and tendons not disposed to repair.