[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.
Department of Orthopedics, General Hospital of Chinese PLA, Beijing 100853, China. zhangyg301@hotmail.com
Yong-gang
YG
Zhang
Wei
W
Zhang
Guo-quan
GQ
Zheng
Ru-yi
RY
Zhang
Hong-zhi
HZ
Zhang
Yan
Y
Wang
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