Wherever possible a tendon should be transplanted directly into bone, as, if it is attached to soft parts it rarely holds firmly enough. The bone should if possible be tunnelled, and the tendon passed through the tunnel and securely fixed. When bringing a tendon to its new point of attachment, it should pass in as straight a line as possible, avoiding any bend or angle which might impair its action. Fat is the best medium for the transplanted tendon to traverse, as it acts as a sheath and prevents the formation of adhesions which would interfere with the function of the new tendon. All deformity must be corrected before transferring the tendon; if the tendon is too short to admit of this, it can be lengthened by means of silk threads (Lange).
According to Jones, the most successful transplantations are the following, in order: (1) The tibialis anterior into the lateral tarsus in paralysis of the peronei; (2) the peroneus longus into the navicular in paralysis of the tibial group; (3) the extensor hallucis longus into any part of the foot where it may be wanted; (4) the hamstrings into the patella, to reinforce the quadriceps, provided the strictest after-treatment can be secured; (5) deflection of part of the tendo Achillis to one or other side of the foot.
Arthrodesis.—This operation, first performed by Albert in 1877, consists in removing the cartilage covering the articular surfaces of bones with the object of producing a firm ankylosis. The procedure is most successful in the ankle and mid-tarsal joints, and as a result of it there is obtained a secure and firm base of support in walking. Before performing arthrodesis, the surgeon must decide whether the patient will be better off with a stiff joint or with a weak and movable ankle supported by apparatus. This is often a matter of social position; in the poor, an ankylosed joint is more useful and less expensive. An arthrodesis should seldom be performed at the ankle until the child has passed his eighth year, or at the knee until he has reached his twentieth year. There is plenty to be done during the period of waiting, and if this is done well, it is possible that the operation may not be required. The existing deformities, for example, will have to be corrected, areas of skin removed to relieve functionless muscles of strain, the body weight appropriately deflected, and the child must be taught to walk with the aid of a support, swinging his limb about, and using it effectively in a correct position. Such exercise is a powerful agent in promoting physiological and functional development.
Nerve anastomosis, which seeks to provide a new channel for the transmission of motor impulses to the paralysed muscles, has as yet a restricted field of application—for example, the tibial and peroneal nerves may be anastomosed when the muscles supplied by one of them are paralysed. Stoffel of Heidelberg lays stress on regard being paid to the anatomical arrangement of the nerve bundles within the nerve-trunk so that motor fibres may be joined to motor ones and not to sensory. It is necessary also to cut across some of the fibres of the healthy nerve in order that they may grow into the nerve which is degenerated.
In extreme cases in which the limb is hopelessly paralysed and useless, it may be amputated to admit of an artificial limb being worn; it must be borne in mind, however, that such limbs furnish poor stumps, usually quite unable to bear pressure.
Cerebral Palsies of Childhood—Spastic Paralysis.—These may be due to arrest of development of the brain, to injuries of the head at birth, to meningeal hæmorrhage, or to other lesions of the brain, with secondary degenerative changes in the spinal cord. The commonest cause is hæmorrhage occurring during child-birth from the veins which ascend from the middle part of the convexity of the hemisphere to open into the superior sagittal (superior longitudinal) sinus. The blood is poured out beneath the dura on one or on both sides of the falx cerebri, and as it accumulates near the vertex, the damage to the motor centres for the legs is usually more extensive than that to the centres for the arms. The paralysis may affect one side of the body—hemiplegia, or both sides—diplegia; less commonly one extremity alone is involved—monoplegia. In diplegia, in which both arms and both legs are affected in the first instance, the arms may recover while the lower extremities remain in a spastic state, a condition known as Little's disease. The mental functions may be normal but more frequently they are imperfectly developed, the impairment in some cases amounting to idiocy. The affected limbs exhibit muscular rigidity or spasm, which is aggravated on movement but disappears under an anæsthetic; the reflexes are exaggerated, and sometimes there are perverted involuntary movements (athetosis). The growth of the limb is impaired, and contracture deformities may supervene ([Fig. 131]). The amount of power in the limb is often astonishing, in marked contrast to what is observed to follow upon anterior poliomyelitis. The degree of natural improvement is by no means great, and normal function is almost never regained.
The treatment is concerned in the first place with improving the condition of the muscles by methodical exercises and massage. When reflex irritability of the muscles with consequent spasm is a prominent feature, the reflex arc may be interrupted by resection of the posterior nerve roots corresponding to the part affected. This operation, first suggested by Spiller but chiefly popularised by Foerster, has yielded the best results in cases of Little's disease, in which there still remains a considerable amount of voluntary movement, and yet there is inability to walk on account of involuntary spasm. In the case of the lower extremities, three or more of the lumbar and one or more of the sacral nerve roots are resected within the vertebral canal. Sensation is diminished but not abolished in the area of skin involved. Massage and exercises and, it may be, splints or apparatus are essential factors in promoting the recovery of function. It has not yet been decided whether the results of the resection of nerve roots justify the risk.
Apart from Foerster's operation, or when it has failed, the spasm of any individual muscle or group of muscles may be got rid of by diminishing the nerve supply to the muscle or by lengthening the tendon. Diminishing the nerve supply was suggested by Stoffel; it consists in exposing the motor nerve as it enters the muscle and resecting one-third or one-half of the fibres so as to reduce the innervation to the required degree. The method is still on its trial.
Lengthening the Tendons.—In spastic paraplegia, for example, Jones resects the origins of the adductors longus and brevis, lengthens the tendo Achillis, divides the popliteal fascia and hamstrings, and transplants the biceps into the quadriceps; after which the limbs are put up in the attitude of wide abduction for six weeks. It is important that the patient should begin to walk with the legs wide apart and learn to balance himself without any feeling of insecurity; he should be taught to look at an object straight in front of him rather than on the ground.