Abstract:

BACKGROUND: It is unknown that how to transfer the impetus of distraction into the message of bone regeneration in limb lengthening.
OBJECTIVE: To study the dynamic expression of inducible nitric oxide synthase (iNOS) in bone lengthening patients. 
METHODS: Totally eight patients whose tibia and fibula are shorten in single lower limb were involved in bone lengthening group. The serum iNOS levels of the patients were measured respectively at 3 days preoperatively, at 3, 7, 8, 11, 13 days postoperatively, stopping bone lengthening, at 3, 15, 30 days after stopping bone lengthening, removing the external lengthening apparatus and at 30 days after removing the external lengthening apparatus. Eight patients with similar age to the bone lengthening group were selected as control.
RESULTS AND CONCLUSION: The serum iNOS levels in the bone lengthening group began to increase at first day after the distraction (the eighth day after operation) and the peak values was at the stopping bone lengthening. The expression of iNOS in the bone lengthening group was significantly higher than that of the control group at every time point from the first day after the distraction to the day of stopping bone lengthening (P < 0.01). The serum iNOS levels in the bone lengthening group at 3 days after stopping the bone lengthening was also higher as compared with the control group (P < 0.05). It is indicated that the higher expression of iNOS is one of the molecular biological mechanisms of bone lengthening.