TY - JOUR
T1 - Three-dimensional correction of scoliosis by a double spring reduction system as a dynamic internal brace
T2 - a pre-clinical study in Göttingen minipigs
AU - Lemans, Justin V.C.
AU - Wijdicks, Sebastiaan P.J.
AU - Overweg, Gerrit
AU - Hekman, Edsko E.G.
AU - Schlösser, Tom P.C.
AU - Castelein, René M.
AU - Verkerke, Gijsbertus J.
AU - Kruyt, Moyo C.
N1 - Funding Information:
The current study was funded through a K2M (now Stryker Spine) Research Grant (R4198). The funder had no influence on the design of the study, collection, analysis and interpretation of the data, writing of the manuscript, nor on the decision to publish. René Castelein and Moyo Kruyt are co-inventors of patent US10610262/AU2018202651, which forms the basis for the development of the spring distraction system (SDS). They are also co-founder of CRESCO spine, a spin-off company that aims to valorize SDS. Edsko Hekman and Gijsbertus Verkerke are co-inventors of patent US9687277B2/EP2849663B1, which forms the basis for the development of the torsional spring implant.
Publisher Copyright:
© 2022 The Author(s)
PY - 2023/4
Y1 - 2023/4
N2 - BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) is a major skeletal deformity that is characterized by a combination of apical rotation, lateral bending and apical lordosis. To provide full 3D correction, all these deformations should be addressed. We developed the Double Spring Reduction (DSR) system, a (growth-friendly) concept that continuously corrects the deformity through two different elements: A posterior convex Torsional Spring Implant (TSI) that provides a derotational torque at the apex, and a concave Spring Distraction System (SDS), which provides posterior, concave distraction to restore thoracic kyphosis. PURPOSE: To determine whether the DSR components are able to correct an induced idiopathic-like scoliosis and to compare correction realized by the TSI alone to correction enforced by the complete DSR implant. STUDY DESIGN/SETTING: Preclinical randomized animal cohort study. PATIENT SAMPLE: Twelve growing Göttingen minipigs. OUTCOME MEASURES: Coronal Cobb angle, T10-L3 lordosis/kyphosis, apical axial rotation, relative anterior lengthening. METHODS: All mini-pigs received the TSI with a contralateral tether to induce an idiopathic-like scoliosis with apical rotation (mean Cobb: 20.4°; mean axial apical rotation: 13.1°, mean lordosis: 4.9°). After induction, the animals were divided into two groups: One group (N=6) was corrected by TSI only (TSI only-group), another group (N=6) was corrected by a combination of TSI and SDS (DSR-group). 3D spinal morphology on CT was compared between groups over time. After 2 months of correction, animals were euthanized. RESULTS: Both intervention groups showed excellent apical derotation (TSI only-group: 15.0° to 5.4°; DSR-group: 11.2° to 3.5°). The TSI only-group showed coronal Cobb improvement from 22.5° to 6.0°, while the DSR-group overcorrected the 18.3° Cobb to -9.2°. Lordosis was converted to kyphosis in both groups (TSI only-group: -4.6° to 4.3°; DSR-group: -5.2° to 25.0°) which was significantly larger in the DSR-group (p<.001). CONCLUSIONS: The TSI alone realized strong apical derotation and moderate correction in the coronal and sagittal plane. The addition of distraction on the posterior concavity resulted in more coronal correction and reversal of induced lordosis into physiological kyphosis. CLINICAL SIGNIFICANCE: This study shows that dynamic spring forces could be a viable method to guide the spine towards healthy alignment, without fusing it or inhibiting its growth.
AB - BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) is a major skeletal deformity that is characterized by a combination of apical rotation, lateral bending and apical lordosis. To provide full 3D correction, all these deformations should be addressed. We developed the Double Spring Reduction (DSR) system, a (growth-friendly) concept that continuously corrects the deformity through two different elements: A posterior convex Torsional Spring Implant (TSI) that provides a derotational torque at the apex, and a concave Spring Distraction System (SDS), which provides posterior, concave distraction to restore thoracic kyphosis. PURPOSE: To determine whether the DSR components are able to correct an induced idiopathic-like scoliosis and to compare correction realized by the TSI alone to correction enforced by the complete DSR implant. STUDY DESIGN/SETTING: Preclinical randomized animal cohort study. PATIENT SAMPLE: Twelve growing Göttingen minipigs. OUTCOME MEASURES: Coronal Cobb angle, T10-L3 lordosis/kyphosis, apical axial rotation, relative anterior lengthening. METHODS: All mini-pigs received the TSI with a contralateral tether to induce an idiopathic-like scoliosis with apical rotation (mean Cobb: 20.4°; mean axial apical rotation: 13.1°, mean lordosis: 4.9°). After induction, the animals were divided into two groups: One group (N=6) was corrected by TSI only (TSI only-group), another group (N=6) was corrected by a combination of TSI and SDS (DSR-group). 3D spinal morphology on CT was compared between groups over time. After 2 months of correction, animals were euthanized. RESULTS: Both intervention groups showed excellent apical derotation (TSI only-group: 15.0° to 5.4°; DSR-group: 11.2° to 3.5°). The TSI only-group showed coronal Cobb improvement from 22.5° to 6.0°, while the DSR-group overcorrected the 18.3° Cobb to -9.2°. Lordosis was converted to kyphosis in both groups (TSI only-group: -4.6° to 4.3°; DSR-group: -5.2° to 25.0°) which was significantly larger in the DSR-group (p<.001). CONCLUSIONS: The TSI alone realized strong apical derotation and moderate correction in the coronal and sagittal plane. The addition of distraction on the posterior concavity resulted in more coronal correction and reversal of induced lordosis into physiological kyphosis. CLINICAL SIGNIFICANCE: This study shows that dynamic spring forces could be a viable method to guide the spine towards healthy alignment, without fusing it or inhibiting its growth.
KW - Double Spring Reduction
KW - Growth
KW - Growth-friendly
KW - Minipigs
KW - Non-fusion
KW - Scoliosis
KW - Spine
UR - http://www.scopus.com/inward/record.url?scp=85144066049&partnerID=8YFLogxK
U2 - 10.1016/j.spinee.2022.10.012
DO - 10.1016/j.spinee.2022.10.012
M3 - Article
C2 - 36343914
AN - SCOPUS:85144066049
SN - 1529-9430
VL - 23
SP - 599
EP - 608
JO - Spine journal
JF - Spine journal
IS - 4
ER -