Diagnostic value of open and needle biopsies in tumors of the sacrum

A retrospective study with statistical analysis of 25 percutaneous needle biopsies and 54 open biopsies performed on 60 patients with tumors located in the sacrococcygeal region.

To analyze the diagnostic value of open and needle biopsies in tumors of the sacrum as well as to determine factors leading to a false or equivocal result.

Although percutaneous needle biopsies of the spine are valuable for thoracolumbar levels, the benefit in the sacrococcygeal region, specifically, has not previously been shown. This region is unique because of anatomic and oncologic factors.

Medical charts, imaging studies, and operative and pathologic records of patients with tumors diagnosed between 1965 and 1996 in the sacrococcygeal region reviewed were analyzed. Accuracy and effective accuracy of each procedure were then calculated.

There were 54 primary lesions (17 benign, 37 malignant) and 6 metastatic tumors. The accuracy and effective accuracy of open biopsies was 87% and 81% but in percutaneous needle biopsies was only 44% and 12%, respectively. An unclear diagnosis resulted in the need for another biopsy in 12 of 21 primary percutaneous needle biopsies but only in 2 of 39 open biopsies (P < 0.0001, chi2). The average number of biopsies required to obtain a definitive diagnosis was significantly less if an open biopsy were performed first instead of a percutaneous needle biopsy, 1.1 versus 1.8, respectively (P = 0.0004, two-sample t test). There was a significant delay in treatment if the initial biopsy was a percutaneous needle biopsy compared with an open biopsy, mean 46 versus 4 days, respectively (P = 0.004, two-sample t test).

We conclude that for sacral tumors, open biopsies have a higher effective accuracy, whereas needle biopsies are associated with a longer delay in treatment.