2023, Vol. 27 ›› Issue (9): 1422-1426

Effect of mechanical tension stress on arterial vessels after limb osteotomy in rabbits

Tang Huiyu, Hou Biao, Xia Xiaodan, Xiang Wei, Xie Songlin   

Abstract: BACKGROUND: Limb lengthening by tensile stress has become an effective measure in the treatment of fracture and limb amputation, but the underlying mechanism of how mechanical tensile stress affects limb arteries and vessels has not been clarified.  
OBJECTIVE: To investigate the effect of slow steady unidirectional mechanical tension stress on limb artery.
METHODS: Totally 75 adult New Zealand rabbits were randomly divided into model control group (the hind limb was amputated and not prolonged), experimental group (the hind limb was amputated and lengthened) and blank group (no limb treatment), with 25 rabbits in each group. The prolonged speed of the experimental group was 0.5 mm/time, twice a day, for 10 days. Saphenous artery specimens were collected at 8, 10, 12, 16, and 19 days (i.e., 3, 5, 7, 11, and 14 days from the start of distraction osteogenesis) after Ilizarov external fixation. The length of saphenous artery was observed and compared. At the same time, X-ray examination was conducted to detect the osteotomy of the affected limb. Arterial structure and inflammatory response were observed by hematoxylin-eosin staining.  
RESULTS AND CONCLUSION: (1) In terms of vascular length: Since the 5th day of Ilizarov external fixation stent pulling, the length of saphenous artery in the experimental group was significantly increased compared with the model control group (P < 0.01). (2) In terms of X-ray examination, at 16 days after osteotomy (i.e., 1 day after the extension ends), the end of osteotomy in the experimental group was extended by about 10 mm, and no callus was formed in the gap. (3) Hematoxylin-eosin staining showed that at 8, 10, 12, 16, and 19 days after external fixation, the arterial tissue structure of the experimental group was intact, without intima vascular injury, smooth muscle cell necrosis or inflammatory cell infiltration. (4) These results indicate that slow and steady unidirectional mechanical stretch stress can prolong the limb arteries and keep the arterial vascular structure stable while lengthening the length of tibial osteotomy end, suggesting that the potential mechanism of stretch stress promoting limb lengthening lies in the stimulation of arterial vascular growth.
Key words: stretch stress, limb lengthening, artery, rabbit, osteotomy