Chinese Journal of Tissue Engineering Research ›› 2020, Vol. 24 ›› Issue (6): 869-876.doi: 10.3969/j.issn.2095-4344.2435

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Digital measurements of the anatomical parameters of pedicle-rib unit screw fixation in thoracic vertebrae of preschoolers

He Yujie1, Wang Haiyan1, Li Zhijun1, 2, Li Xiaohe1, Cai Yongqiang1, 2, Dai Lina1, Xu Yangyang3, Wang Yidan3, Xu Xuebin3   

  1. 1Department of Anatomy of Basic Medical School, 2Center of Digital Medicine, Inner Mongolia Medical University, Hohhot 010059, Inner Mongolia Autonomous Region, China; 3Graduate School, Inner Mongolia Medical University, Hohhot 010010, Inner Mongolia Autonomous Region, China
  • Received:2019-06-03 Revised:2019-06-11 Accepted:2019-07-15 Online:2020-02-28 Published:2020-01-17
  • Contact: Li Zhijun, Master, Professor, Department of Anatomy of Basic Medical School, Center of Digital Medicine, Inner Mongolia Medical Universiey, Hohhot 010059, Inner Mongolia Autonomous Region, China Li Xiaohe, MD, Professor, Master’s supervisor, Department of Anatomy of Basic Medical School, Inner Mongolia Medical Universiey, Hohhot 010059, Inner Mongolia Autonomous Region, China
  • About author:He Yujie, Master candidate, Lecturer, Department of Anatomy of Basic Medical School, Inner Mongolia Medical Universiey, Hohhot 010059, Inner Mongolia Autonomous Region, China Wang Haiyan, Master, Associate professor, Master’s supervisor, Department of Anatomy of Basic Medical School, Inner Mongolia Medical Universiey, Hohhot 010059, Inner Mongolia Autonomous Region, China He Yujie and Wang Haiyan contributed equally to this work.
  • Supported by:
    the National Natural Science Foundation of China, No. 81560348 and 81860383, No. 81460330; the Science and Technology Leading Project of the Department of Finance of Inner Mongolia Autonomous Region, No. 2017; the Youth Elite of Science and Technology Project of the Department of Education of Inner Mongolia Autonomous Region, No. njyt-15-b05; the Inner Mongolia Autonomous Region Science and Technology Program, No. 2016; the Science and Technology Innovation Leading Project of Inner Mongolia Autonomous Region, No. 2017; the Natural Science Foundation of Inner Mongolia Autonomous Region, No. 2016MS08131; the Fund for Returnees from the Department of Human Resources and Social Security of Inner Mongolia Autonomous Region; the Science and Technology Million Program of Inner Mongolia Medical University, No. YKD2017KJBW012

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Abstract:

BACKGROUND: Pedicle screw internal fixation has been widely used in the lumbar spine, and fixed application in thoracic vertebra has gradually been accepted. Considering the narrow thoracic pedicle, especially at T3-T9, pedicle screw always punctures the cortex and important adjacent structures. To avoid serious complications, researchers developed the external pedicle approach from the costal transverse process joint and the costal vertebra joint to the vertebral body, and then others designed a similar screw entry method, which can provide enough safe paths as long as the ribs are not penetrated. At present, the existing studies mainly focus on the upper and middle thoracic vertebrae in adults.

OBJECTIVE: To measure the anatomical parameters of pedicle-rib unit screw fixation in thoracic vertebrae of preschoolers, and to explore their developmental regularity and morphological characteristics at different age groups and sexes, so as to provide theoretical basis for clinical practice.

METHODS: Sixty-seven preschoolers aged 7-12 years old without bone destruction, tumor, deformity, degeneration or fractures at the spine and no history of spine related surgery were selected. Three-dimensional reconstruction was conducted after spiral CT scanning. The morphological structure of pedicle-rib unit was observed. The transverse diameter, length, inclination angle and safety angle range of pedicle-rib unit screw were measured and analyzed statistically to investigate the feasibility of screw on anatomy. All guardians of the children signed the informed consents, and the study was approved by the hospital ethical committee.

RESULTS AND CONCLUSION: (1) The transverse diameter of the thoracic pedicle-rib unit was increased with age, and decreased first and then increased with the increase of vertebral sequence. The transverse diameter in males was larger than in females at the same age. (2) The length of pedicle-rib screw channel was significantly different in different age groups (P < 0.05), which showed a significant increase with age and a trend of first increase and then decrease with the increase of vertebral sequence. (3) Pedicle-rib unit screw placement showed that safety angle range was 18°-25°, including maximum safety scope in T1, followed by T10, minimum in T4 and T5. (4) Thus, security angle range of pedicle-rib unit screw in children is narrower than that in adults. Compliance with the adult standards in screw placement may cause severe nerve damage to the nerves and blood vessels, so preoperative individualized screw placement should be carried out according to the CT results.

Key words: thoracic vertebra, pedicle-rib unit, developmental features, school-age children, individualized screw, internal fixation, the National Natural Science Foundation of China

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