[Changes of blood circulation of the extremity with tibia shaft defects treated with external fixation].

OBJECTIVE

To study external skeletal fixation for long tubular bony defect by end to end compression with lengthening (EECL) and segmental bone transport by lengthening (STBL).

METHODS

About 20% - 30% of the original length was resected from the middle shaft of the tibia in 10 goats of 1 - 2 years of age. The bony defect ends were shortened step by step with the sulcated half-ring external fixator. Changes of the blood flow of the distant extremity were measured with pulse-dopplar monitor, reference blood flow, and angiograph.

RESULTS

The blood flow of the distant extremity was not affected when bony defect was less than 15% of the original length. Blood circulation disorder would appear in the distant extremity when bony defect ranged from 15% to 20% of the original length. The distant extremity would necrose because of obstruction of blood circulation when bony defect was more than 20% of the original length.

CONCLUSIONS

EECL can be recommended if bony defect is less than 15% of the original length. SBTL might be the only feasible way if bony defect is more than 20% of the original length. If bony defect is within 15% and 20%, EECL should be applied with great care while watching the extremity circulation with pulse-Dopplar monitor.