Neurocentral synchondrosis screws to create and correct experimental deformity: a pilot study.
BACKGROUND
Unilateral pedicle screw epiphysiodesis of the neurocentral synchondrosis (NCS) can produce asymmetric growth of the synchondrosis to create scoliosis in an immature animal model.


OBJECTIVE
We asked whether a preexisting experimentally created scoliosis could be limited and corrected by modulating the growth of the faster-growing NCS by a similar method.


METHODS
Nine 1-month-old pigs were assigned to each of three groups: (1) a sham group in which three animals received a sham operation but without a pedicle screw fixation; (2) an experimental group with double right pedicle screws placed across the NCS from T7 to T14 (scoliosis-untreated); and (3) an experimental group treated in the same way except a second set of double pedicle screws was placed in the left pedicles 6 weeks after the screws were placed on the right (scoliosis-treated). All animals were euthanized at 17 weeks, and radiographs and axial CT images of the spine were obtained.


RESULTS
A scoliotic curve was not seen in any of the animals in the sham group, in three of three in the scoliosis-untreated group with an average of 34°, and in three of three in the scoliosis-treated group with an average of 20°. In comparison to the scoliosis-untreated group, the second set of pedicle screws produced a 41% correction of the scoliosis.


CONCLUSIONS
We found the pedicle screw inhibited the overgrowth of the NCS to prevent further curve progression and obtained some correction of the deformity. The NCS screw epiphysiodesis can create and reverse scoliosis in an immature pig model.
Zhang
Hong
H
The Center for Excellence in Spine Research, Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219, USA. hong.zhang@tsrh.org
Sucato
Daniel J
DJ
D000818:Animals; D000831:Animals, Newborn; D001863:Bone Screws; D004195:Disease Models, Animal; D006132:Growth Plate / Q000254:growth & development / Q000601:surgery*; D019637:Orthopedic Procedures / Q000295:instrumentation*; D010865:Pilot Projects; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery*; D012720:Severity of Illness Index; D013552:Swine; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000254:growth & development / Q000601:surgery*; D013997:Time Factors; D014057:Tomography, X-Ray Computed