Increased Renal retention of 99mTc-methylene diphosphonate after nephron-sparing surgery

Nephron-sparing surgery has become established as an effec tive treatment for localized renal cell carcinoma when preserva tion of renal function is necessary. The surgery usually requires temporary renal artery occlusion and may induce ischemie renal damage. In this study, we retrospectively evaluated renal activity on bone scintigraphy after nephron-sparing surgery. Methods: Eleven patients who underwent nephron-sparing surgery for renal cell carcinoma and had a normal contralateral kidney were studied. A total of 12 bone scintigraphy images with 99mTc-labeled mA©thylA¨ne diphosphonate were obtained within 1 y after surgery in these patients to assess skeletal metastasis. Activity in the spared renal parenchyma was compared visually with that in the contralateral normal kidney. Results: The tumor was success fully resected in every patient, and no clinically significant complications occurred. Activity in the spared renal parenchyma was elevated in six of seven examinations performed within 21 d after surgery. In three examinations, the increase in renal activity was heterogeneous, being relatively prominent near the surgical margin. Increased renal activity was not observed on five examinations performed 3 mo or more after surgery. Conclu sion: Renal retentionof bone-seekingagentsis elevated in the early period after nephron-sparing surgery, probably as a result of ischemie insult during the surgical procedure. Bone scintigra phy may aid in evaluating the presence and degree of ischemie damage of the spared renal parenchyma.