OBJECTIVETo present that Nickel-Titanium (NT) memory alloy staples in fusionless controlling the growth of the vertebrates in the sagittal plane.

METHODSEighteen infant female goats were selected and equally divided into 3 random groups: long staple group, short staple group and blank control group. Five long staple (the legs' length = 7 mm) and five short staple (the legs' length = 4 mm) were implanted into each goat in long and short staple groups respectively by anterior approach, right on the front of the thoracic vertebrae from T(6) to T(11). The control group was not given any treatment. X-ray examination was performed pre-operatively and post-operatively. Cobb angle of lateral radiograph was measured and the data of Cobb angle were statistically analyzed. At the end of the experiment, whether the staples implanted spinal columns were fused or not were evaluated by gross observation.

RESULTSFinally, all of the goats were included in the final results. Before the operations, T(6-11) sagittal Cobb angle was 7.0° ± 2.3° in short staple group, and 6.2° ± 4.0° in long staple group. And after the operation, the T(6-11) Cobb angle was increased to 12.7° ± 4.7° in short staple group with the increased rate of 81.4%, and 14.0° ± 4.9° in long staple group with the increased rate of 125.8%, respectively. Before and after the surgery, there were no significant differences between long staple group and short staple group in terms of Cobb angle (pre-operation P = 0.655, post-operation P = 0.596). Before the surgery, there were no differences in terms of Cobb angle, between long staple groups and control group (P = 0.929), and short staple groups and control group (P = 0.720). At the end of the experiment, there were significant differences between long staple group and control group in terms of Cobb angle (P = 0.007), and between short staple group and control group (P = 0.021). The staples implanted spinal columns were not fused which was proved by gross observation.

CONCLUSIONSThe memory alloy staple implantation by anterior approach, right on the front of the thoracic vertebrae of goats, can control the growth of thoracic vertebrates leading to kyphosis.