Multiple envelope tissue expander device

Claim 1

An implantable, multiple envelope tissue expander device for the controlled expansion of tissue consisting essentially of: (A) a first inflatable biocompatible envelope having a first inflation means associated therewith for the controlled inflation of said first envelope with a biocompatible fluid, said first envelope having a lower half to which a fixation means is attached and by which fixation means said first envelope is secured to an underlying body member beneath a section of tissue to be expanded to hold said first envelope in a preselected orientation with respect to the tissue to be expanded, and (B) a second inflatable, biocompatible envelope attached to the surface of that half of the first envelope which is opposite said underlying member, said second envelope having a second inflation means associated therewith, separate from said first inflation means, for the controlled inflation of said second envelope with a biocompatible fluid, said second envelope having a shape and a volume capacity which, upon appropriate inflation, is smaller in volume capacity than said first envelope and permits tissue overlying said second envelope to be expanded outwardly from said underlying body member to a greater extent than that tissue which overlies the remaining upper surface of said first envelope to thereby cause the overlying tissue to substantially assume the shape of the upper surfaces of the fully inflated envelopes.

Claim 7

A method of expanding tissue to form an area of tissue having a preselected shape which comprises the steps of (I) implanting beneath a section of tissue to be expanded a multiple envelope tissue expander device consisting essentially of (A) a first inflatable biocompatible envelope having a first inflation means associated therewith for the controlled inflation of said first envelope with a biocompatible fluid, said first envelope having a lower half to which a fixation means is attached and by which means said first envelope is secured to an underlying body member beneath the tissue to be expanded to hold said first envelope in a preselected orientation with respect to the tissue to be expanded, and (B) a second inflatable, biocompatible envelope which is attached to the surface of that half of the first envelope which is opposite said underlying member, said second envelope having a second inflation means associated therewith, separate from said first inflation means, for the controlled inflation of said second envelope with a biocompatible fluid, said second envelope having a shape and a volume capacity which, upon appropriate inflation, is smaller in volume capacity than said first envelope and permits tissue overlying said second envelope to be expanded outwardly from said underlying body member to a greater extent than that tissue which overlies the remaining upper surface of said first envelope to thereby cause the overlying tissue to assume the approximate shape of the upper surfaces of the fully inflated envelopes, (II) securing said fixation means to said underlying body member to hold said envelopes in a preselected orientation with respect to the tissue to be expanded, (III) inflating said first envelope gradually over a period of time to expand the tissue overlying said first envelope, (IV) inflating said second envelope gradually over a period of time to expand the tissue overlying said second envelope to a greater extent than is accomplished by the inflation of said first envelope, and (V) removing said expander.

Claim 8

A method of expanding tissue to form an area of tissue having a preselected shape which comprises the steps of (I) implanting beneath a section of tissue to be expanded a multiple envelope tissue expander device consisting essentially of (A) a first inflatable biocompatible envelope having a first inflation means associated therewith for the controlled inflation of said first envelope with a biocompatible fluid, said first envelope having a lower half to which a fixation means is attached and by which means said first envelope is secured to an underlying body member beneath the tissue to be expanded to hold said first envelope in a preselected orientation with respect to the tissue to be expanded, and (B) a second inflatable, biocompatible envelope which is attached to the surface of that half of the first envelope which is opposite said underlying member, said second envelope having a second inflation means associated therewith, separate from said first inflation means, for the controlled inflation of said second envelope with a biocompatible fluid, said second envelope having a shape and a volume capacity which, upon appropriate inflation, is smaller in volume capacity than said first envelope and permits tissue overlying said second envelope to be expanded outwardly from said underlying body member to a greater extent than that tissue which overlies the remaining upper surface of said first envelope to thereby cause the overlying tissue to assume the approximate shape of the upper surfaces of the fully inflated envelopes, (II) securing said fixation means to said underlying body member to hold said envelopes in a preselected orientation with respect to the tissue to be expanded, (III) inflating said first envelope gradually over a period of time to expand the tissue overlying said first envelope, (IV) inflating said second envelope gradually over a period of time to expand the tissue overlying said second envelope to a greater extent than is accomplished by the inflation of said first envelope, and (V) removing said expander.