A pituitary cup biopsy is more accurate than reamings for histological diagnosis of intramedullary lesions during nailing of impending and pathologic fractures: a retrospective matched cohort analysis.

Abstract

Histologic diagnosis of the lesion is important while intramedullary nailing of a pathologic or impending fracture of a long bone. A biopsy can be performed extramedullary using a targeted sampling device such as a pituitary rongeur or intramedullary from the bone removed from the reamer during preparation of the intramedullary canal. The purpose of this study is to compare a cup pituitary rongeur vs. a reaming biopsy from the intramedullary canal during the treatment of pathologic bone lesions with an intramedullary nail. An IRB approved retrospective case control study was performed on 46 consecutive patients who underwent an IMN for pathologic fracture or impending pathologic fracture with an obvious lytic lesion with a known metastatic primary. A laryngeal cup pituitary forceps' rongeur was used in 25 patients and the intramedullary reamer as it passed the lesion was used in 21 patients. Histopathology reports were assessed for (1) adequacy of bone sample (defined as containing sufficient bone and marrow-derived tissue to allow complete histological analysis) and (2) tumor tissue diagnosis. A standard approach for IMN was used. Twenty-three of 25 cup biopsy cases (92%) had positive pathology that corresponded to the primary cancer. Eleven of 21 reaming cases (52.4%) had positive pathology that corresponded to the primary cancer (p = 0.0117). The use of an intramedullary cup biopsy forceps is better than reamings to diagnose pathological lesions of impending and pathological fractures in long bones caused by metastatic lesions.