[Experimental study on controlling unilateral spine growth by shape memory alloy staple].
OBJECTIVE
To observe the effects that shape memory alloy (SMA) staples implanted to the lateral aspect of the thoracic vertebrae on spinal growth in goats.


METHODS
Sixteen goats (age 2 - 3 months) were divided into 3 groups: six in single staple group; six in double staples group and four in control group. Single staples group underwent right-side thoracotomy for exposing the thoracic spine through the eighth rib. Five SMA staples were placed laterally into vertebral bodies of T(6 - 11) spanning discs. Double staples group underwent the same operation. Laterally directed 10 SMA staples were placed into vertebrae of T(6 - 11) spanning discs and two staple spanning each disc. The last four goats in control groups just only underwent right-side thoracotomy. In the next 4 months after operation, radiographs were taken to observe the spinal growth every month.


RESULTS
The radiographic analysis demonstrated scoliosis of 12.83 degrees +/- 12.17 degrees in single staple group and 12.00 degrees +/- 3.22 degrees in double staple group after 2 months of the operation. Cobb angle of 6.00 degrees +/- 4.94 degrees and 25.17 degrees +/- 3.71 degrees were observed in the two groups respectively after 4 months of operation, as compared with 0 degrees in the control groups. Only 2 goats developed kyphosis.


CONCLUSIONS
Compression between vertebral bodies by SMA staples can depress spinal growth in the same side and greater compression result in larger curves.
Zhang
Yong-gang
YG
Department of Orthopedics, General Hospital of Chinese PLA, Beijing 100853, China. zhangyg301@hotmail.com
Zhang
Wei
W
Zheng
Guo-quan
GQ
Zhang
Ru-yi
RY
Zhang
Hong-zhi
HZ
Wang
Yan
Y
D000497:Alloys; D000818:Animals; D001858:Bone Nails; D005260:Female; D006041:Goats; D013131:Spine / Q000254:growth & development*; D013904:Thoracic Vertebrae / Q000601:surgery*; D013908:Thoracotomy / Q000295:instrumentation / Q000379:methods
D000497:Alloys