Biomedical Engineering Reference
In-Depth Information
8
Bone Remodeling under Pulsed
Electromagnetic Fields and
Clinical Ap
plications
8.1 Introduction
This chapter deals with the PEMF devices that have been widely used clini-
cally to treat nonunion fracture, accelerate bone fracture recovery, and slow
down osteoporosis. It is an extension of Chapters 6 and 7 to the case of bone
remodeling under PEMF. The theoretical and numerical results presented
in Wang and Qin [1] are described. Typically, a computational method of
system biology is used for analyzing bone remodeling under PEMF at the
cellular level, based on experimental findings and recent mathematical
advances.
The use of electrical stimulation in bone can be dated back almost 200 years to
when a patient with tibia nonunion was successfully cured in 1812 [2]. In 1957,
Fukuda and Yasuda [3] discovered the piezoelectric feature of bone, in that
when bone was under compression an electronegative potential was induced,
whereas an electropositive potential was produced by bone under tension.
In 1991, Grande et al. [4] found that the controlling signal seemed to be the
electric potential generated by shear piezoelectricity in collagen fibers and/or
the streaming potential in canaliculae. These two discoveries raised the pos-
sibility that the behavior of bone cells could be affected by externally applied
electrical stimuli [5]. Bassett [6] appears to have been the first to use a pair of
Helmholtz coils to produce a magnetic field across a fracture site and enhance
osteogenesis. Qin and Ye [7], Qin, Qu, and Ye [8], Qin [9], Qu, Qin, and Kang
[10], and Qu and Qin [11] studied multifield bone remodeling processes exten-
sively, using the concept of adaptive piezoelectric theory.
Early in the 1990s, several major forms of electrical stimulation were
reported to produce osteogenesis, including capacitively and inductively
coupled electromagnetic and direct current fields [12,13]. Since then, research
into electrically induced osteogenesis in bone has been carried out using
these methods both in vivo and in vitro [12,14-16]. The osteogenetic effect on
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