NECROSIS.—Death of bone may not only be due to osteomyelitis, but, also, as already stated, to periostitis. What ever be its pathogenic source, however, it ensues as a result of defective nutri tion due to interference with the sup ply of arterial blood. This occurs when the medullar or periosteal lesion that may be present leads to destruction of the Haversian canals. At times the de ficient nutrition may be due to numer ous emboli originating in a remote re gion—in the heart, for instance. during endocarditis. Metastatic necrosis is also occasionally witnessed in the course of infectious diseases, the result probably of bacillary invasion. Under Jaws, DIS EASES OF, the necros.it brought on by phosphorus has been carefully reviewed. The influence of malnutrition of osseous tissue is readily shown also in dislocation of the astragalus; notwithstanding its replacement and the fact that no exter nal lesions exist, this bone may undergo necrosis. The influence of fractures is also well known, especially when com minution disrupts its trophic supply.
When a long bone is attacked, the whole shaft may be involved or only that part of the diaphysis near the epiphyseal line. The periosteurn forms new bone over the dead tissues or sequestrum and a suppurative tract or sinus leads from the sequestrum through the surrounding shell of bone to the exterior.
Etiology and litis is the result of an infection from one of the pyogenic organisms, either a streptococcus or staphylococcus. The disease is usually started by some slight injury, particularly in children previ ously debilitated by the infectious fevers.
In the negro race childhood and early manhood are most prone to the disease. Cold, traumatism, and are frequent existing causes.
Study of 403 cases of acute osteomye litis of the long bones. Shows that the male sex preponderates over the female in the proportion of 3.33 to 1. A large percentage, 42, falls between the ages of 13 and 17. Below 6 and beyond 19 there is considerable decrease; beyond 19, al most extinction. Three-fifths of all cases occur in the larger cylindrical bones, :3S between tibia and femur,—the latter more in the lower third, the former more in the centre of the shaft; 20 per cent. multiple. In 189 of the entire number more or less aggravated disturbance of the adjacent articulations remained. Haaga (Belt. zur. klin. Chir., vol. v, No. 1, '90).
Series of 32 eases of osteomyelitis in children. Staphylococci were found in 11 cases; streptococci, typhoid bacilli, and pneumocoeci in 1 case each. In young children the prognosis is grave; otherwise the results were excellent.
Death occurred in 12.5 per cent. Gonser (Jahrbuch f. Kinderh.. July. 1902).
In 107 cases of osteomyelitis the joints were affected in 4S. The disease was lo cated in the diaphysis of the femur in 45; in the upper epiphysis in 15; lower epiphysis in 3; diaphysis of humerus, 1S; upper epiphysis, 1; lower, 4; diaphysis tibia, 45; upper epiphysis, 3; lower, 1; diaphysis fibula. 5; lower epiphysis, 1; diaphysis radius. 4; upper epiphysis, 2; upper epiphysis ulna, 2; distal epiphyses metatarsals, 3; upper epiphyses meta carpals. 1; diaphysis phalanges, 2; and the lower epiphyses in 1 case.
The osteomyelitis was usually found in young individuals, generally before puberty. Traumatism did not seem to play an active part in the production of the epiphyseal osteomyelitis. In the eases in which a bacteriological examina tion was made, the staphylococcus amens and allms were found. Becker (Deutsche Zeit. f. ChM., March. 1902).
The pathology of bone-necrosis cor responds to that of gangrene observed in soft tissues. Dead bone is separated from living bone by a line of demarka tion of inflammatory origin: a rarefying ostitis. This tends to isolate the dead bone, which then becomes a sequestrum. It may, if small enough, be absorbed after undergoing disintegration; if large, it may persist' a long time imbedded in pus, which finally finds an issue. The enveloping shell,—the involucrum,—if it contains a sufficient quantity of pus, be comes perforated, and, this perforation leading to the surface, a fistula is formed. The reproduction of bone in necrosis due to simple inflammatory causes is sometimes remarkable when the subject is strong. Indeed, there is sometimes overproduction, elongation of a limb being thus brought about, especially an injury requiring prolonged sojourn in the recumbent position.
Treatment.—When a joint is affected it may first be aspirated; if the effusion is marked or if the case is sufficiently alarming the articulation may be laid open, washed out, and drained or even the joint resected.
In case the long bones are involved free incision and drainage should be re sorted to in order to cut short the sys temic disturbance and allow time for the periosteum to become sufficiently thick ened to allow of its being pushed aside while removal of the affected bone is being accomplished.
In some cases longitudinal section with Hey's saw, and curettage are re quired to totally evacuate the contents; a small trephine may be used when the accumulation is not readily accessible and the purulent material is thickened.