In a prospective study of stress injuries of the lower extremities of U.S. Marine recruits, we derived a frequency distribution of stress fractures. The most frequently fractured bone was the tibia (73%), while the single most common site was the posterior calcaneal tuberosity (21%). The natural history of stress fractures by scintigraphy and radiography has been outlined, showing the evolutionary changes on either study as a universal progression independent of injury site or type of stress. An identical spectrum of changes should be present within any group undergoing intense new exercise. The frequency distribution of stress fractures should be a function of differing forms and intensities of exercise, therefore, our figures should not be applied to other groups. We used the presence of a scintigraphic abnormality at a symptomatic site as the criterion for diagnosis of stress fracture. Since the distribution of skeletal radiotracer uptake is directly dependent on local metabolic activity, it is expected that a focal alteration in bone metabolism will result in a scintigram approaching 100% sensitivity for the abnormality (9). In the proper clinical setting, the specificity should approximate this figure; however, a focal, nonstress-related bone abnormality which has not manifested any radiographic change, such as early osteomyelitis, could result in a false-positive examination. Specificity cannot, therefore, be accurately determined without an actual determination of the pathologic changes within the bone, necessarily involving biopsy. In summary, we believe that we have established bone scintigraphy as an early and accurate means for the detection of lower extremity stress fractures, even in the absence of radiographic findings (6). We feel that a focally abnormal scintigram, in the proper clinical setting, establishes the diagnosis of stress fracture, with radiography to be performed at the time of initial work-up only to rule out a non-stress injury (such as complete fracture, fibrous dysplasia, osteomyelitis, primary bone tumor).

With use of 99mtechnetium-labeled phosphates, we performed preoperative bone scans on 122 women with biopsy-proved breast carcinoma. Only two of the 110 patients with Stage I or II disease had scan abnormalities interpreted as bone metastases. Of 55 patients with normal preoperative scans, 20 later had changes suggesting bone metastases on the subsequent scans, most within 24 months of operation. In women with Stage I and II tumors, 13 of 48 (27 per cent) had scan evidence of bone metastasis of postoperative follow-up examination. Five of 23 with potential surgical cures (negative lymph nodes at operation) had bone metastasis within two years of operation. In Stage I and II patients, postoperative discovery of evolving metastases was most often (11 to 13) made by bone scan. Although the initial yield from preoperative bone scans is low, preoperative scanning combined with sequential postoperative scans constitutes one of the most sensitive indicators of evolving metastatic disease.

Preoperative embolization of renal arteries with solid material before nephrectomy is a standard procedure for the treatment of renal cell carcinoma. However, it often is difficult to use these materials and sometimes special equipment is required. We have used 95 per cent ethyl alcohol in 3 patients to devitalize kidneys with tumors. Our results show 95 per cent ethyl alcohol to be safe, effective and easy to use. When combined with epidural anesthesia alcohol embolization is well tolerated by the patient, and its destructive effect is complete and limited to the selected organ.