Chinese Journal of Tissue Engineering Research ›› 2011, Vol. 15 ›› Issue (26): 4872-4875.doi: 10.3969/j.issn.1673-8225.2011.26.031

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Research progress in stability of pedicle screw

Zhou Zi-hong1, Cheng Li1, Yin Qu-dong2   

  1. 1Department of Orthopedics, Wuxi People’s Hospital, Wuxi  214000, Jiangsu Province, China
    2Department of Orthopedics, Wuxi Orthopedic Hospital, Wuxi  214000, Jiangsu Province, China
  • Received:2011-02-22 Revised:2011-03-16 Online:2011-06-25 Published:2011-06-25
  • About author:Zhou Zi-hong★, Master, Attending physician, Department of Orthopedics, Wuxi People’s Hospital, Wuxi 214000, Jiangsu Province, China yinqudong@sina.com

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Abstract:

BACKGROUND: Pedicle screw which passes through the three columns and has three-dimensional correction function, which has quickly become the standard posterior spinal internal fixation. But loss of correction and screw loosening often occurs in patients with osteoporosis, or screw has less stability in revision surgery and re-adjust of screw position.
OBJECTIVE: To summarize and analyze the stability of pedicle screw, to introduce the methods of improving the stability of pedicle screw and its clinical applications.
METHODS: A computer-based online search of PubMed database, CNKI database, VIP database was performed for related articles published between 1990 and 2010 with key words “bone nails, osteoporosis, revision, pedicle screw, stability” in English and Chinese.
RESULTS AND CONCLUSION: The focus on increasing stability of pedicle screw is to increase screw withdrawal resistance. Screw augmented with bone cement or replaced with thicker, longer screws or special screws (hollow screw and expandable screw hole) can lead to increase in the absolute value of screw stability. Screws in the upper and the lower, the left and the right side with different connectors, different directions of placement will affect the stability of the entire device of pedicle screw, which is the change in the relative value of screw stability. Other methods are those such as improving structure of fixator, and adding with bone in screw-path, etc. Various methods have advantages and disadvantages, clinical application should be based on different situations to choose specific methods. In general for Osteoporosis below grade Ⅱ (Jikei grade), using thicker and longer screws, horizontal connection device and screws with stiff connection with rod. At the same time, screws in left and right, upper and down side placed with larger angle to increase the stability of pedicle screw is a safe and convenient way; for Osteoporosis grade Ⅱ or more , more reliable screw augmented method with bone cement or special screws to increase the stability of pedicle screw must be used.

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