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US 5,273,028 AGranted
Non-invasive means for in-vivo bone-growth stimulation
OwnerKenneth J. McLeod, Clinton T. Rubininventors
Life of this patent
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Abstract
A method and apparatus for preventing osteopenia, promoting bone tissue growth, ingrowth, and healing of bone tissue includes the step of and apparatus for applying a mechanical load to the bone tissue at a relatively low level on the order of between about 50 and about 500 microstrain peak-to-peak, and at a relatively high frequency, preferably in the range of about 15 and about 55 Hz. Mechanical loading at such strain levels and such frequencies has been found to prevent bone loss and enhance new bone formation.
Claims54
Apparatus for stimulating bone growth in a living vertebrate body of given mass, said apparatus comprising:
- upper and lower essentially rigid plates of area sufficient to support the living body when the spine is upright,
- stiffly compliant means disposed between said plates for vertically compliant coupling of said plates when oriented horizontally for gravitational loading of the upper plate against the lower plate,
- dynamic-force transducer means interposed between said plates and oriented to vertically drive said upper plate with respect to said lower plate,
- means associated with said lower plate for retaining an assembled relation of said plates and said compliant means and said transducer means, with freedom for relative displacement of said plates while compliantly coupled,
- whereby when the lower one of said plates is set upon a horizontal support surface, the upper one of said plates is upwardly facing and positioned for support of a living body with upright spine,
- said compliant means having a spring constant such that, in the context of the total mass of said upper plate and the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz;
- variable-frequency signal-generator means for driving said transducer means at said resonant frequency and within a range up to an upper limit of about 2.0-mm displacement peak-to-peak;
- signal-generator means including
- (a) means for varying within said frequency range, the frequency of signal output of said generator means, and
- (b) means responsive to the instantaneous electric-current value of said signal output, whereby to adjust the varied frequency to a value at which the instantaneous current value is at minimum,
- said signal-generator means further including amplitude-control means for adjusting the instantaneous amplitude of said signal output;
- and
- a motion-indicating sensor carried by said upper plate for indicating the instantaneous motion of said upper plate within said upper limit of displacement peak-to-peak.
10 more elements
Apparatus for stimulating bone growth in a vertebrate living body of given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- stiffly compliant means on the underside of said plate for support of said plate upon a relatively rigid horizontal support surface,
- dynamic-force transducer means carried by the underside of said plate and oriented to vertically drive said plate with referencing reaction to the relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- variable-frequency signal-generator means for driving said transducer means at said resonant frequency and within a range up to an upper limit of about 2.0-mm displacement peak-to-peak;
- said signal-generator means including
- (a) means for varying, within said frequency range, the frequency of signal output of said generator means, and
- (b) means responsive to the instantaneous electric-current value of said signal output, whereby to adjust the varied frequency to a value at which the instantaneous current value is at minimum,
- said signal-generator means further including amplitude-control means for adjusting the instantaneous amplitude of said signal output;
- and
- a motion-indicating sensor carried by said plate for indicating the instantaneous motion of said plate within said upper limit of displacement peak-to-peak.
8 more elements
Apparatus for stimulating bone growth in a vertebrate living body of given mass, said apparatus comprising:
- an essentially rigid upper plate of area sufficient to support the living body when the spine is upright,
- a rigid lower plate forming part of a rigid frame structure which includes a peripheral rim above at least a portion of said upper plate, with said upper plate exposed within said rim for support of the living body,
- stiffly compliant means in the form of peripherally distributed pairs of upper and lower springs under tensed preload, the upper springs being connected to said upper plate and to said rim, and the lower springs being connected to said upper plate and to said lower plate whereby said upper plate is suspended with respect to said frame structure by all said springs under tensed preload,
- dynamic-force transducer means interposed between said plates and oriented to vertically drive said upper plate with respect to said lower plate;
- said compliant means having a spring constant such that, in the context of the total mass of said upper plate and the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- variable-frequency signal-generator means for driving said transducer means at said resonant frequency and within a range up to an upper limit of about 2.0-mm displacement peak-to-peak;
- said signal-generator means including
- (a) means for varying, within said frequency range, the frequency of signal output of said generator means, and
- (b) means responsive to the instantaneous electric-current value of said signal output, whereby to adjust the varied frequency to a value at which the instantaneous current value is at minimum,
- said signal-generator means further including amplitude-control means for adjusting the instantaneous amplitude of said signal output;
- and
- a motion-indicating sensor carried by said plate for indicating the instantaneous motion of said plate within said upper limit of displacement peak-to-peak.
9 more elements
Apparatus for stimulating bone growth in a living vertebrate body of given mass, said apparatus comprising:
- upper and lower essentially rigid plates of area sufficient to support the living body when the spine is upright,
- stiffly compliant means disposed between said plates for vertically compliant coupling of said plates when oriented horizontally for gravitational loading of said upper plate against said lower plate,
- dynamic-force transducer means interposed between said plates and oriented to vertically drive said upper plate with respect to said lower plate;
- means associated with said lower plate for retaining an assembled relation of said plates and said compliant means and said transducer means, with freedom for relative displacement of said plates while compliantly coupled,
- whereby when the lower one of said plates is set upon a horizontal support surface the upper one of said plates is upwardly facing and positioned for support of a living body with upright spine,
- said compliant means having a spring constant such that, in the context of the total mass of said upper plate and the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating-current signal generator with means for selectively varying the output frequency within said range of naturally resonant frequencies;
- and
- means for monitoring an instantaneous motional value of said upper plate at natural resonance and in the course of frequency variation, whereby to establish the natural resonance for an applied individual's body mass.
7 more elements
Apparatus for stimulating bone growth in a living vertebrate body of given mass, said apparatus comprising:
- upper and lower essentially rigid plates of area sufficient to support the living body when the spine is upright,
- stiffly compliant means disposed between said plates for vertically compliant coupling of said plates when oriented horizontally for gravitational loading of said upper plate against said lower plate,
- dynamic-force transducer means interposed between said plates and oriented to vertically drive said upper plate with respect to said lower plate;
- means associated with said lower plate for retaining an assembled relation of said plates and said compliant means and said transducer means, with freedom for relative displacement of said plates while compliantly coupled,
- whereby when the lower one of said plates is set upon a horizontal support surface the upper one of said plates is upwardly facing and positioned for support of a living body with upright spine,
- said compliant means having a spring constant such that, in the context of the total mass of said upper plate and the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating-current signal generator with means for selectively varying the magnitude of output current to said transducer means;
- and
- means carried by said upper plate for monitoring a quantity reflecting an instantaneous motional value of said upper plate at natural resonance, whereby to enable selective adjustment of the magnitude of current supplied to said transducer means, to or within a predetermined monitored limit.
7 more elements
Apparatus for stimulating bone growth in a living vertebrate body of given mass, said apparatus comprising:
- upper and lower essentially rigid plates of area sufficient to support the living body when the spine is upright,
- stiffly compliant means disposed between said plates for vertically compliant coupling of said plates when oriented horizontally for gravitational loading of said upper plate against said lower plate,
- dynamic-force transducer means interposed between said plates and oriented to vertically drive said upper plate with respect to said lower plate;
- means associated with said lower plate for retaining an assembled relation of said plates and said compliant means and said transducer means, with freedom for relative displacement of said plates while compliantly coupled,
- whereby when the lower one of said plates is set upon a horizontal support surface the upper one of said plates is upwardly facing and positioned for support of a living body with upright spine,
- said compliant means having a spring constant such that, in the context of the total mass of said upper plate and the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating current signal generator with means for selectively varying the magnitude of output current to said transducer means;
- and
- accelerometer means carried by said upper plate for monitoring the instantaneous value of a maximum dynamic acceleration of said upper plate at said natural resonance so as to assure control of output current to an upper limit corresponding to a maximum monitored dynamic acceleration value of 0.3 g.
7 more elements
Apparatus for stimulating bone growth in a living vertebrate body of given mass, said apparatus comprising:
- upper and lower essentially rigid plates of area sufficient to support the living body when the spine is upright,
- stiffly compliant means disposed between said plates for vertically compliant coupling of said plates when oriented horizontally for gravitational loading of said upper plate against said lower plate,
- dynamic-force transducer means interposed between said plates and oriented to vertically drive said upper plate with respect to said lower plate;
- means associated with said lower plate for retaining an assembled relation of said plates and said compliant means and said transducer means, with freedom for relative displacement of said plates while compliantly coupled,
- whereby when the lower one of said plates is set upon a horizontal support surface the upper one of said plates is upwardly facing and positioned for support of a living body with upright spine,
- said compliant means having a spring constant such that, in the context of the total mass of said upper plates and the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz;
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating current signal generator with means for selectively varying the magnitude of output current to said transducer means;
- and
- displacement-responsive monitoring means carried by said upper plate for monitoring the instantaneous value of peak-to-peak displacement of said upper plate at said natural resonance so as to assure control of output current to an upper limit corresponding to a maximum monitored peak-to-peak displacement of 2.0 mm.
7 more elements
Apparatus for stimulating bone growth in a living vertebrate body of a given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- means for supporting said plate including stiffly compliant means engaged to said plate,
- dynamic-force transducer means engaged to the underside of said plate and oriented to vertically drive said plate with referencing reaction to a relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 100 Hz, and
- variable-frequency signal-generator means for driving said transducer means at said resonant frequency and within a range up to an upper limit of about 2.0-mm displacement peak-to-peak;
- said signal-generator means including
- (a) means for varying, within said frequency range, the frequency of signal output of said generator means, and
- (b) means responsive to the instantaneous electric-current value of said signal output, whereby to adjust the varied frequency to a value at which the instantaneous current value is at minimum,
- said signal-generator means further including amplitude-control means for adjusting the instantaneous amplitude of said signal output;
- and
- a motion-indicating sensor carried by said plate for indicating the instantaneous motion of said plate within said upper limit of displacement peak-to-peak.
8 more elements
Apparatus for stimulating bone growth in a vertebrate living body of given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- stiffly compliant means on the underside of said plate for support of said plate upon a relatively rigid horizontal support surface,
- dynamic-force transducer means carried by the underside of said plate and oriented to vertically drive said plate with referencing reaction to the relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating-current signal generator with means for selectively varying the output frequency within said range of naturally resonant frequencies;
- and
- means for monitoring an instantaneous motional value of said upper plate at natural resonance and in the course of frequency variation, whereby to establish the natural resonance for an applied individual's body mass.
5 more elements
Apparatus for stimulating bone growth in a vertebrate living body of given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- stiffly compliant means on the underside of said plate for support of said plate upon a relatively rigid horizontal support surface,
- dynamic-force transducer means carried by the underside of said plate and oriented to vertically drive said plate with referencing reaction to the relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating current signal generator with means for selectively varying the magnitude of output current to said transducer means;
- and
- means carried by said plate for monitoring a quantity reflecting an instantaneous motional value of said plate at natural resonance, whereby to enable selective adjustment of the magnitude of current supplied to said transducer means to or within a predetermined monitored limit.
5 more elements
Apparatus for stimulating bone growth in a vertebrate living body of given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- stiffly compliant means on the underside of said plate for support of said plate upon a relatively rigid horizontal support surface,
- dynamic-force transducer means carried by the underside of said plate and oriented to vertically drive said plate with referencing reaction to the relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating-current signal generator with means for selectively varying the magnitude of output current to said transducer means;
- and
- accelerometer means carried by said upper plate for monitoring the instantaneous value of a maximum dynamic acceleration of said upper plate at said natural resonance so as to assure control of output current to an upper limit corresponding to a maximum monitored dynamic acceleration value of 0.3 g.
5 more elements
Apparatus for stimulating bone growth in a vertebrate living body of given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- stiffly compliant means on the underside of said plate for support of said plate upon a relatively rigid horizontal support surface,
- dynamic-force transducer means carried by the underside of said plate and oriented to vertically drive said plate with referencing reaction to the relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 50 Hz,
- means for driving said transducer means at said resonant frequency and within a range up to 2.0-mm displacement peak-to-peak;
- said means for driving said transducer means being an alternating-current signal generator with means for selectively varying the magnitude of output current to said transducer means, and
- displacement-responsive monitoring means carried by said plate for monitoring the instantaneous value of peak-to-peak displacement of said plate at said natural resonance so as to assure control of output current to an upper limit corresponding to a maximum monitored peak-to-peak displacement of 2.0 mm.
4 more elements
Apparatus for stimulating bone growth in a living vertebrate body of a given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- means for supporting said plate including stiffly compliant means engaged to said plate,
- dynamic-force transducer means engaged to the underside of said plate and oriented to vertically drive said plate with referencing reaction to a relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range of 10 Hz to 100 Hz,
- variable-frequency signal-generator means connected to drive said transducer means at said resonant frequency and within a range up to an upper limit of about 2.0-mm displacement peak-to-peak;
- presettable means for setting the frequency output of said signal-generating means to a preascertained value of said naturally resonant frequency,
- a motion-indicating sensor carried by said plate for providing an electrical-signal output that reflects instantaneous motion of said plate within said upper limit of displacement peak-to-peak, and
- feedback-control means responsive to said electrical-signal output and having an amplitude-control connection to said signal-generator means.
5 more elements
Apparatus for stimulating bone growth in a living vertebrate body of given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- means for supporting said plate including stiffly compliant means engaged to said plate,
- dynamic-force transducer means engaged to the underside of said plate and oriented to vertically drive said plate with referencing reaction to a relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 100 Hz,
- variable-frequency signal-generator means for driving said transducer means at said resonant frequency and within a range up to an upper limit of about 2.0-mm displacement peak-to-peak;
- and
- automatic means for ascertaining said naturally resonant frequency, comprising:
- scanning means for varying the frequency output of said signal-generator means within said range of frequencies, and
- means responsive to instantaneous current supplied by said generator means to said transducer means in a course of frequency variation, for identifying a frequency at which instantaneous current is at minimum value within said range of frequencies.
6 more elements
Apparatus for stimulating bone growth in a living vertebrate body of a given mass, said apparatus comprising:
- an essentially rigid plate of area sufficient to support the living body when the plate is horizontal and the spine is upright,
- means for supporting said plate including stiffly compliant means engaged to said plate,
- dynamic-force transducer means engaged to the underside of said plate and oriented to vertically drive said plate with referencing reaction to a relatively rigid support surface,
- said compliant means having a spring constant such that, in the context of the total of the mass of said plate and the mass of the plate-supported body mass, said total mass and said compliant means exhibit a naturally resonant frequency in the range 10 Hz to 100 Hz,
- variable-frequency signal-generator means for driving said transducer means at said resonant frequency and within a range up to an upper limit of about 2.0-mm displacement peak-to-peak;
- and
- control means for said signal-generator means including:
- (a) means for varying, within said frequency range, the frequency of signal output of said generator means,
- (b) means responsive to the instantaneous electric-current value of said signal output, whereby to adjust the varied frequency to a value at which the instantaneous current value is at minimum,
- (c) amplitude-control means for adjusting the instantaneous amplitude of said signal output, and
- (d) feedback-control means including a motion-indicating sensor carried by said plate for producing an electrical signal indicative of said instantaneous motion, and said sensor being connected to said amplitude-control means for maintaining a predetermined level of sensor output in the course of a given treatment.
8 more elements
Dependencies are inferred from the claim text.