Therapeutic effects of one-year alendronate treatment in three cases of osteoporosis with parietal thinning of skull

We studied the therapeutic effects of one-year alendronate treatment in three cases (two males and one female) of osteoporosis with parietal thinning of skull. Plain radiography and three dimensional computed tomography revealed asymmetric external thinning of the posteromedial part of the bilateral parietal bones. Technetium-99m methylenediphosphate bone scintigraphy did not show any changes in these three cases. Pretreatment levels of urinary type I collagen cross-linked N-telopeptides (NTX) in all three cases were high compared to the normal range. Pretreatment levels of serum bonespecific alkaline phosphatase (BAP) in the two male patients were high in contrast to the normal values in the female patient. Pretreatment mean bone mineral density (BMD) values of the 2nd to 4th lumbar vertebrae (L2-4BMD), head BMD, femoral neck BMD, and whole body BMD of all three patients were low compared with the respective normal ranges. One-year alendronate treatment decreased both urinary NTX and serum BAP in all three cases to normal values. Treatment also increased the whole body BMD in all three cases, the L2-4BMD of the female patient, the femoral neck BMD of the female patient and one male patient, and the head BMD of the female patient when compared to pretreatment levels.