[A study on experimental pyogenic osteomyelitis. 1. The preferential site of hematogenous osteomyelitis. 2. The role of foreign body in hematogenous infection (author's transl)].

The author undertook the experiments as described below in order to determine the preferential site of hematogenous osteomyelitis and possible effects of foreign bodies in the bone marrow on development of infection. I) In the first experiment, mice were inoculated with 10(7) cells of staphylococcus aureus intravenously into the tail vein and examined for the distribution and proliferation of the organisms in the bones, all over the body. It was found that the orgaisms in the blood stream were distributed to the bones all over the body almost evenly and that after prolonged observation, remarkable proliferation was noted in both femur and tibia. This bacteriological fact was supported by roentgenographic examination of all the bones. II) In the second experiment, inoculation of staphylococcus aureus into the tail vein was made after a foreign body (No. 5 sterile silk thread of 3 mm in lenght) had been inserted into the proximal metaphysis of a tibia of mice. The tibia of both legs was divided into 3 parts: proximal metaphysis, diaphysis and distal metaphysis. Observation were made for the distribution of organisms and state of proliferation in each of these three parts. In order to elucidate how the inserted foreign body promoted the establishment of infection, the group inserted with silk thread was compared with the control group (un-inserted group). The following results were obtained: 1. Although after 2 weeks of inoculation, the foreign body exerted no influences on the distribution and proliferation of organisms, but it was experimentally demonstrated to play a very important role for retention of organisms and maintenance of infection for a long period. 2. When the inoculum size was 10(6) to 10(7), the organisms were distributed evenly throughout the tibia. However, in the diaphysis the organisms tended to disappear, while in the metaphyseal area the organisms were easy to proliferate. It was also shown that at least 10(5) of organisms were needed for the establishment of infection and that the success or failure of establishment of infection is determined usually within 24 hours after inoculation of the organisms. As described above, from this study it was demonstrated that the femur and tibia were the preferential site of hematogenous osteomyelitis and that metaphyseal areas of the long bones were commonly affected. Once hematogenous invasion of organisms occurred, administration of antibiotics should be started as soon as possible, no later than 24 hours. According to our common experience, removal of foreign body is necessary for the complete cure of the injection.