Unilateral pedicle screw epiphysiodesis of the neurocentral synchondrosis production of idiopathic-like scoliosis in an immature animal model

Hong Zhang, Daniel J. Sucato

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Background: The neurocentral synchondrosis plays a role in the growth of the spine. The goal of this study was to determine whether asymmetric epiphysiodesis of this synchondrosis creates a scoliotic deformity in a growing-animal model and to correlate curve magnitude with the degree of closure of the synchondrosis. Methods: Two-month-old pigs were assigned to three groups. In the control group, two animals received a shamoperation without pedicle screw fixation; in the single-screw group, three animals were treated with a single right transpedicular screw placed across the neurocentral synchondrosis from T7 to T14; and in the double-screw group, three animals were treated in the same way as the previous group except that two screws were placed in each pedicle. The animals were killed at six months, and radiographs and axial computed tomography images of the spine were obtained. Histomorphometric analyses were performed to grade the synchondrosis at each level. Results: A scoliotic curve was seen in none of the animals in the control group, in one of the three in the single-screw group, and in all three in the double-screw group (30°, 42°, and 42°). Vertebral rotation in the axial plane occurred toward the screw side and was significantly greater in the double-screw group (mean, 15.2°) than in the single-screw (mean, 6.1°) and control (0°) groups (p < 0.001). There was no difference in morphology between the left and right pedicles in the control group. The left pedicle was 9% longer than the right (screw-treated) pedicle in the single-screwgroup, and it was 22% longer than the right pedicle in the double-screw group. Closure of the neurocentral synchondrosis was greatest in the double-screw group (>75% closure) compared with the single-screw group (<50% closure) (p < 0.0001) and the control group (no closure) (p < 0.0001), and closure correlated with the magnitude of the coronal curve (p = 0.001). Conclusions: Unilateral transpedicular screw fixation that traverses the neurocentral synchondrosis in a growing-pig model can produce asymmetric growth of the synchondrosis to create scoliosis with the convexity on the side of the screw fixation. Double pedicle screws provided a greater epiphysiodesis effect on the neurocentral synchondrosis, which correlated with a greater degree of scoliosis. Clinical Relevance: This young-animal model demonstrates that asymmetric closure of the neurocentral synchondrosis produces structural scoliosis due to continued growth of the opposite pedicle. This non-fusion strategymay have some role in the treatment of growing patients with spinal deformity.

Original languageEnglish (US)
Pages (from-to)2460-2469
Number of pages10
JournalJournal of Bone and Joint Surgery - Series A
Volume90
Issue number11
DOIs
StatePublished - Nov 1 2008

Fingerprint

Scoliosis
Animal Models
Control Groups
Spine
Swine
Growth
Tomography
Pedicle Screws

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

Cite this

@article{93bb748aede74f65879445c20ade9929,
title = "Unilateral pedicle screw epiphysiodesis of the neurocentral synchondrosis production of idiopathic-like scoliosis in an immature animal model",
abstract = "Background: The neurocentral synchondrosis plays a role in the growth of the spine. The goal of this study was to determine whether asymmetric epiphysiodesis of this synchondrosis creates a scoliotic deformity in a growing-animal model and to correlate curve magnitude with the degree of closure of the synchondrosis. Methods: Two-month-old pigs were assigned to three groups. In the control group, two animals received a shamoperation without pedicle screw fixation; in the single-screw group, three animals were treated with a single right transpedicular screw placed across the neurocentral synchondrosis from T7 to T14; and in the double-screw group, three animals were treated in the same way as the previous group except that two screws were placed in each pedicle. The animals were killed at six months, and radiographs and axial computed tomography images of the spine were obtained. Histomorphometric analyses were performed to grade the synchondrosis at each level. Results: A scoliotic curve was seen in none of the animals in the control group, in one of the three in the single-screw group, and in all three in the double-screw group (30°, 42°, and 42°). Vertebral rotation in the axial plane occurred toward the screw side and was significantly greater in the double-screw group (mean, 15.2°) than in the single-screw (mean, 6.1°) and control (0°) groups (p < 0.001). There was no difference in morphology between the left and right pedicles in the control group. The left pedicle was 9{\%} longer than the right (screw-treated) pedicle in the single-screwgroup, and it was 22{\%} longer than the right pedicle in the double-screw group. Closure of the neurocentral synchondrosis was greatest in the double-screw group (>75{\%} closure) compared with the single-screw group (<50{\%} closure) (p < 0.0001) and the control group (no closure) (p < 0.0001), and closure correlated with the magnitude of the coronal curve (p = 0.001). Conclusions: Unilateral transpedicular screw fixation that traverses the neurocentral synchondrosis in a growing-pig model can produce asymmetric growth of the synchondrosis to create scoliosis with the convexity on the side of the screw fixation. Double pedicle screws provided a greater epiphysiodesis effect on the neurocentral synchondrosis, which correlated with a greater degree of scoliosis. Clinical Relevance: This young-animal model demonstrates that asymmetric closure of the neurocentral synchondrosis produces structural scoliosis due to continued growth of the opposite pedicle. This non-fusion strategymay have some role in the treatment of growing patients with spinal deformity.",
author = "Hong Zhang and Sucato, {Daniel J.}",
year = "2008",
month = "11",
day = "1",
doi = "10.2106/JBJS.G.01493",
language = "English (US)",
volume = "90",
pages = "2460--2469",
journal = "Journal of Bone and Joint Surgery - American Volume",
issn = "0021-9355",
publisher = "Journal of Bone and Joint Surgery Inc.",
number = "11",

}

TY - JOUR

T1 - Unilateral pedicle screw epiphysiodesis of the neurocentral synchondrosis production of idiopathic-like scoliosis in an immature animal model

AU - Zhang, Hong

AU - Sucato, Daniel J.

PY - 2008/11/1

Y1 - 2008/11/1

N2 - Background: The neurocentral synchondrosis plays a role in the growth of the spine. The goal of this study was to determine whether asymmetric epiphysiodesis of this synchondrosis creates a scoliotic deformity in a growing-animal model and to correlate curve magnitude with the degree of closure of the synchondrosis. Methods: Two-month-old pigs were assigned to three groups. In the control group, two animals received a shamoperation without pedicle screw fixation; in the single-screw group, three animals were treated with a single right transpedicular screw placed across the neurocentral synchondrosis from T7 to T14; and in the double-screw group, three animals were treated in the same way as the previous group except that two screws were placed in each pedicle. The animals were killed at six months, and radiographs and axial computed tomography images of the spine were obtained. Histomorphometric analyses were performed to grade the synchondrosis at each level. Results: A scoliotic curve was seen in none of the animals in the control group, in one of the three in the single-screw group, and in all three in the double-screw group (30°, 42°, and 42°). Vertebral rotation in the axial plane occurred toward the screw side and was significantly greater in the double-screw group (mean, 15.2°) than in the single-screw (mean, 6.1°) and control (0°) groups (p < 0.001). There was no difference in morphology between the left and right pedicles in the control group. The left pedicle was 9% longer than the right (screw-treated) pedicle in the single-screwgroup, and it was 22% longer than the right pedicle in the double-screw group. Closure of the neurocentral synchondrosis was greatest in the double-screw group (>75% closure) compared with the single-screw group (<50% closure) (p < 0.0001) and the control group (no closure) (p < 0.0001), and closure correlated with the magnitude of the coronal curve (p = 0.001). Conclusions: Unilateral transpedicular screw fixation that traverses the neurocentral synchondrosis in a growing-pig model can produce asymmetric growth of the synchondrosis to create scoliosis with the convexity on the side of the screw fixation. Double pedicle screws provided a greater epiphysiodesis effect on the neurocentral synchondrosis, which correlated with a greater degree of scoliosis. Clinical Relevance: This young-animal model demonstrates that asymmetric closure of the neurocentral synchondrosis produces structural scoliosis due to continued growth of the opposite pedicle. This non-fusion strategymay have some role in the treatment of growing patients with spinal deformity.

AB - Background: The neurocentral synchondrosis plays a role in the growth of the spine. The goal of this study was to determine whether asymmetric epiphysiodesis of this synchondrosis creates a scoliotic deformity in a growing-animal model and to correlate curve magnitude with the degree of closure of the synchondrosis. Methods: Two-month-old pigs were assigned to three groups. In the control group, two animals received a shamoperation without pedicle screw fixation; in the single-screw group, three animals were treated with a single right transpedicular screw placed across the neurocentral synchondrosis from T7 to T14; and in the double-screw group, three animals were treated in the same way as the previous group except that two screws were placed in each pedicle. The animals were killed at six months, and radiographs and axial computed tomography images of the spine were obtained. Histomorphometric analyses were performed to grade the synchondrosis at each level. Results: A scoliotic curve was seen in none of the animals in the control group, in one of the three in the single-screw group, and in all three in the double-screw group (30°, 42°, and 42°). Vertebral rotation in the axial plane occurred toward the screw side and was significantly greater in the double-screw group (mean, 15.2°) than in the single-screw (mean, 6.1°) and control (0°) groups (p < 0.001). There was no difference in morphology between the left and right pedicles in the control group. The left pedicle was 9% longer than the right (screw-treated) pedicle in the single-screwgroup, and it was 22% longer than the right pedicle in the double-screw group. Closure of the neurocentral synchondrosis was greatest in the double-screw group (>75% closure) compared with the single-screw group (<50% closure) (p < 0.0001) and the control group (no closure) (p < 0.0001), and closure correlated with the magnitude of the coronal curve (p = 0.001). Conclusions: Unilateral transpedicular screw fixation that traverses the neurocentral synchondrosis in a growing-pig model can produce asymmetric growth of the synchondrosis to create scoliosis with the convexity on the side of the screw fixation. Double pedicle screws provided a greater epiphysiodesis effect on the neurocentral synchondrosis, which correlated with a greater degree of scoliosis. Clinical Relevance: This young-animal model demonstrates that asymmetric closure of the neurocentral synchondrosis produces structural scoliosis due to continued growth of the opposite pedicle. This non-fusion strategymay have some role in the treatment of growing patients with spinal deformity.

UR - http://www.scopus.com/inward/record.url?scp=55849124680&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=55849124680&partnerID=8YFLogxK

U2 - 10.2106/JBJS.G.01493

DO - 10.2106/JBJS.G.01493

M3 - Article

C2 - 18978416

AN - SCOPUS:55849124680

VL - 90

SP - 2460

EP - 2469

JO - Journal of Bone and Joint Surgery - American Volume

JF - Journal of Bone and Joint Surgery - American Volume

SN - 0021-9355

IS - 11

ER -