Venous drainage through bone marrow after replantation: an experimental study.

Venous drainage is vital for successful replantation, but it is not always possible to reconstruct because of missing or damaged veins. We devised an experimental model to study venous drainage through bone marrow while the new subcutaneous venous system regenerated. Adult male Wistar rats were placed into three groups. Group A rats had their hindlimbs amputated at the lower leg, but the tibia and sural and saphenous artery connections were preserved. Group B rats were prepared the same as Group A, except that a step-cut osteotomy was performed in the tibia. The bone ends were then realigned and kept in place with stainless steel wire. Group C rats were prepared the same as Group B, except that the ends of the bone were not aligned. All unoperated limbs served as controls for evaluations of blood flow. Experimental limbs were evaluated for skin colour and viability, blood flow and dye injection. Skin colour was investigated daily. Blood flow was measured postoperatively during three phases: immediate (up to 1 h), early (from 1 h to 24 h), and late (from 1 day to 7 days after operation). Survival of limbs varied in Groups A and B, while all limbs in Group C necrosed by day 7. Blood flow was returning to near control (normal) levels by day 7 in Group A and B limbs. India ink was observed in the medullary cavity at day 7. After replantation, bone marrow plays a critical role in venous drainage until the subcutaneous venous drainage system regenerates.