Thermal MRI safe tissue expander port
View Patent ↗Improvements for use with tissue expanders are provided. A tissue expander includes: a selectively inflatable and deflatable shell that is configured to be implanted; and an access port for selectively inflating and deflating the shell, the access port comprising a sidewall, a base at a first end, and a membrane at a second end opposite the first end wherein the sidewall and the base of the access port are constructed of a material that is non-reactive with a magnetic resonance imaging (MRI) machine; and a structure of the access port is composed of a material that has a rate of temperature change lower than that of human tissue.
1. A tissue expander, comprising:
a selectively inflatable and deflatable shell that is configured to be implanted; and
an access port for selectively inflating and deflating the shell, the access port comprising a sidewall, a base at a first end, and a membrane at a second end opposite the first end,
wherein the sidewall and the base of the access port are constructed of a material that is non-reactive with a magnetic resonance imaging (MRI) machine; and
a structure of the access port is composed of a material that has a rate of temperature change lower than that of human tissue.
2. The tissue expander of claim 1 , wherein the material is a non-metallic and non-ferromagnetic material.
3. The tissue expander of claim 1 , wherein the material is a non-metallic and non-ferromagnetic polymer.
4. The tissue expander of claim 1 , wherein the material is has a heat capacity that is higher than the nominal heat capacity of the human body.
5. The tissue expander of claim 4 , wherein the material is has a heat capacity that is different than a heat capacity of other portions of the tissue expander.
6. The tissue expander of claim 1 , wherein the material is has a specific heat capacity that is higher than the nominal specific heat capacity of the human body.
7. The tissue expander of claim 6 , wherein the material is has a specific heat capacity that is higher than the nominal specific heat capacity of the human body.
8. The tissue expander of claim 1 , wherein:
the membrane is pierceable by a needle; and
the sidewall and the base function as a hard-stop that limit travel of the needle within access port after the needle has pierced the membrane.
9. A tissue expander, comprising:
a selectively inflatable and deflatable shell that is configured to be implanted; and
an access port for selectively inflating and deflating the shell, the access port comprising a sidewall, a base at a first end, and a membrane at a second end opposite the first end,
wherein the sidewall and the base of the access port are constructed of a material that is non-reactive with a magnetic resonance imaging (MRI) machine; and
a structure of the access port comprises a portion having a specific heat capacity greater than 3.47 kJ/(kg*K).
10. A method, comprising:
bringing a tissue expander into thermal equilibrium with surrounding tissue in which the tissue expander is implanted, wherein the tissue expander comprises: a selectively inflatable and deflatable shell that is configured to be implanted; and an access port for selectively inflating and deflating the shell, the access port comprising a sidewall, a base at a first end, and a membrane at a second end opposite the first end, wherein the sidewall and the base of the access port are constructed of a material that is non-reactive with a magnetic resonance imaging (MRI) machine, and a structure of the access port is composed of a material that has a rate of temperature change lower than that of human tissue;
applying external cooling to the surrounding tissue;
based on the external cooling, detecting the structure using an infrared sensor; and
inserting a needle into the access port while using the infrared sensor as a guide.