Comparative Study of Bone Necrosis between Phenol Cautery and Cryosurgery to the Defects in the Porcine Femur and Tibia

Park, Il Hyung; Ihn, Joo Chul; Lee, Sang Wook; Sohn, Kyung Rak; Chun, In Ho

Abstract

A corticocancellous core was removed from both femurs and tibias in 5 skeletally immature pigs. The cavity was treated with 5%, 25% phenol cautery, cryosurgery, and normal saline irrigation (control). The animals were sacrified after 7days. The extent of the bone necrosis was assessed by gross examination, simple radiography, MRI evaluation and histological examination with tissue mapping. After cryosurgery, the extent of necrosis was most profound in the depth of 2.0-9.0mm beyond the cavity wall. The effect of 25%-phenol was next to cryosurgery, with a depth of 1.0-3.0mm of necrosis. 5%-phenol made necrosis with the depth of 1.0-2.5mm. Very mild degree of necrosis with the width of 0.5-1.0mm was found along the cavity wall even in control group. On MRI, signal change was well visualized on T2 weighted coronal section and it was quite coincided with the extent of bone necrosis proved by histological tissue mapping to all cases. When the epiphyseal plate was open or very close to the cavity, curettage itself, 5%- and 25%-phenol cautery and cryosurgery all produced mild ischemic necrosis along the provisional calcification zone of physeal plate. These findings suggest that cryosurgery made more profound necrosis beyond cavity than phenol cautery and MRI is very sensitive and specific to find osteonecrosis along the cavity wall after phenol cautery or cryosurgery. When epiphyseal plate is open or very close to the cavity, phenol cautery, or cryosurgery, or even curettage itself could produce an ischemic necrosis to the physeal plate itself.