Apparatus and methods for accessing and dilating bone structures using a narrow gauge cannula

A catheter/expandable element assembly for medical applications comprising a conforming catheter shaft having proximal and distal ends, an expandable element having a conforming expandable balloon portion bonded at the distal end of the catheter shaft, and a fluid passageway extending from a proximal end of the catheter shaft to the interior of the balloon portion of the expandable element, wherein the balloon portion has been inflated to a size and/or inflation pressure and for a time sufficient to complete a vertebral treatment procedure and thereafter has been deflated and stretched, folded and/or wrapped to a maximum diameter of less than 0.092 inches, the assembly being characterized by one or more of the following features:

• (a) the assembly includes a juncture between the catheter shaft and a proximal balloon neck portion that will fit through the interior of a standard 11-gauge medical cannula;
• (b) the assembly includes a juncture between the catheter shaft and a proximal balloon neck portion that will fit through the interior of a standard 11-gauge medical cannula without the use of any lubricant or similar friction-reducing substance;
• (c) the catheter shaft is a single lumen catheter shaft and the assembly includes both a stretched, folded and/or wrapped balloon portion and a juncture between the catheter shaft and a proximal balloon neck portion that will fit through the interior of a standard 11-gauge medical cannula;
• (d) the expandable element comprises a proximal neck portion that is butt-jointed by an adhesive bonding procedure, a solvent bonding procedure and/or a thermal bonding procedure to the distal end of the catheter shaft;
• (e) the expandable element comprises a distal neck portion having a sealed tip, and the sealed tip contains the only radiopaque marker along the expandable element;
• (f) the expandable element comprises one or more bands of a radiopaque material under a balloon portion of the expandable element with or without radiopaque material at a distal tip of the expandable element;
• (g) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly;
• (h) the assembly additionally comprises a mandrel element that extends from an interior proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly and further wherein a distal end of the mandrel is bonded to the interior distal end of the assembly;
• (i) the assembly additionally comprises a catheter bifurcation assembly at the proximal end of the catheter shaft;
• (j) the assembly additionally comprises a catheter bifurcation assembly at a proximal end having an inflation arm portion and a mandrel arm portion, where the mandrel arm portion is substantially in axial alignment with the catheter shaft;
• (k) the assembly additionally comprises a catheter bifurcation assembly at a proximal end having an inflation arm portion and a mandrel arm portion, where the mandrel arm portion is substantially in axial alignment with the catheter shaft and further wherein the proximal end of the mandrel arm portion provides an enclosed sleeve for limited axial movement of the mandrel and the proximal end of the mandrel is of an enlarged size such that the proximal end of the mandrel is retained in the sleeve;
• (l) the assembly additionally comprises a mandrel element and a balloon-wrapping and/or tensioning device for actively or passively applying axial and/or rotational forces to the balloon portion following a balloon inflation and treatment procedure and subsequent deflation but prior to the withdrawal step causing the balloon portion to stretch axially and/or to wrap at least in part around the mandrel element to reduce the profile of the balloon portion and thereby facilitate a withdrawal step;
• (m) the assembly additionally comprises a mandrel element that extends from an interior proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly, and further wherein a distal end of the mandrel is bonded to the distal end of the assembly and an unbonded proximal end of the mandrel has an enlarged geometrical feature that can move axially along or parallel to the axis of the catheter shaft but only within an enclosed sleeve that is bounded at its proximal end by the interior proximal end of the assembly and is bounded at its distal end by a mandrel retaining structure;
• (n) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly, wherein a distal portion of the mandrel is of a reduced diameter relative to a more proximal portion of the mandrel;
• (o) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion;
• (p) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils;
• (q) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also wherein there is greater spacing between adjacent spring coils along a distal portion of the spring than along a more proximal spring portion;
• (r) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also wherein the spring is covered by a polymeric sleeve;
• (s) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also wherein the proximal end of the mandrel extends proximally of the assembly and terminates in an enlarged geometrical feature whereby the mandrel can be axially tensioned by pulling on that proximal mandrel end so as to compress the spring where the hooked mandrel tip engages the spring coils and thereby causing the distal end of the expandable element to temporarily deflect from an axial orientation for as long as the mandrel is axially tensioned;
• and,
• (t) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also comprising a mandrel tensioning assembly consisting of two threadably-engaged mandrel tensioning elements at the proximal end of the catheter/expandable element assembly whereby the threadably-engaged tensioning elements provide an axial channel in which the proximal end of the mandrel can slide such that rotating one tensioning element relative to the other causes one of the tensioning elements to move in a proximal direction relative to the second element thereby applying axial tensioning to the mandrel and causing deflection of the hooked mandrel tip and the distal tip of the expandable element as long as the axial tensioning is applied.

A method for carrying out a vertebral medical treatment that includes a dilatation and/or a cavity creation, enlargement or treatment procedure that is performed with an expandable conforming balloon using a catheter/expandable element assembly comprising a conforming catheter shaft having proximal and distal ends, an expandable element having a conforming balloon portion bonded at the distal end of the catheter shaft, and a fluid passageway extending from a proximal end of the catheter shaft to the interior of the balloon portion of the expandable element, wherein the assembly is characterized by one or more of the following features:

• (a) the expandable element comprises a conforming balloon which can be stretched, folded and/or wrapped before and after inflation of the balloon to a maximum diameter of less than 0.092 inches;
• (b) the assembly includes both a stretched, folded and/or wrapped balloon and a juncture between the catheter shaft and a proximal balloon neck portion that will fit through the interior of a standard 11-gauge medical cannula before and after inflation of the balloon;
• (c) the assembly includes both a stretched, folded and/or wrapped balloon and a juncture between the catheter shaft and a proximal balloon neck portion that will fit through the interior of a standard 11-gauge medical cannula before and after inflation of the balloon without the use of any lubricant or similar friction-reducing substance;
• (d) the expandable element can be stretched, folded and/or wrapped to sufficiently reduce the cross-sectional profile of the assembly before and after inflation of the balloon to be compatible with the use of a narrow gauge cannula;
• (e) the expandable element can be stretched, folded and/or wrapped to sufficiently reduce the cross-sectional profile of the assembly before and after inflation of the balloon to be compatible with the use of an 11-gauge or smaller-diameter cannula;
• (f) the catheter shaft is a single lumen catheter shaft and the assembly includes both a stretched, folded and/or wrapped balloon and a juncture between the catheter shaft and a proximal balloon neck portion that will fit through the interior of a standard 11-gauge medical cannula before and after inflation of the balloon;
• (g) the expandable element comprises a proximal neck portion that is butt jointed by an adhesive bonding procedure, a solvent bonding procedure and/or a thermal bonding procedure to the distal end of the catheter shaft;
• (h) the expandable element comprises a distal neck portion having a sealed tip, and the sealed tip contains the only radiopaque marker along the expandable element;
• (i) the expandable element comprises one or more bands of a radiopaque material under a balloon portion of the expandable element with or without radiopaque material at a distal tip of the expandable element;
• (j) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly;
• (k) the assembly additionally comprises a mandrel element that extends from an interior proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly and further wherein a distal end of the mandrel is bonded to the interior distal end of the assembly;
• (l) the assembly additionally comprises a catheter bifurcation assembly at the proximal end of the catheter shaft;
• (m) the assembly additionally comprises a catheter bifurcation assembly at a proximal end having an inflation arm portion and a mandrel arm portion, where the mandrel arm portion is substantially in axial alignment with the catheter shaft;
• (n) the assembly additionally comprises a catheter bifurcation assembly at a proximal end having an inflation arm portion and a mandrel arm portion, where the mandrel arm portion is substantially in axial alignment with the catheter shaft and further wherein the proximal end of the mandrel arm portion provides an enclosed sleeve for limited axial movement of the mandrel and the proximal end of the mandrel is of an enlarged size such that the proximal end of the mandrel is retained in the sleeve;
• (o) the assembly additionally comprises a mandrel element and a balloon-wrapping and/or tensioning device for actively or passively applying axial and/or rotational forces to the balloon portion following a balloon inflation and treatment procedure and subsequent deflation but prior to the withdrawal step causing the balloon portion to stretch axially and/or to wrap at least in part around a mandrel element to reduce the profile of the balloon portion and thereby facilitate the withdrawal step;
• (p) the assembly additionally comprises a mandrel element that extends from an interior proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly, and further wherein a distal end of the mandrel is bonded to the distal end of the assembly and an unbonded proximal end of the mandrel has an enlarged geometrical feature that can move axially along or parallel to the axis of the catheter shaft but only within an enclosed sleeve that is bounded at its proximal end by the interior proximal end of the assembly and is bounded at its distal end by a mandrel retaining structure;
• (q) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and through the expandable element to an interior distal end of the assembly, wherein a distal portion of the mandrel is of a reduced diameter relative to a more proximal portion of the mandrel;
• (r) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion;
• (s) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils;
• (t) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also wherein there is greater spacing between adjacent spring coils along a distal portion of the spring than along a more proximal spring portion;
• (u) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also wherein the spring is covered by a polymeric sleeve;
• (v) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also wherein the proximal end of the mandrel extends proximally of the assembly and terminates in an enlarged geometrical feature whereby the mandrel can be axially tensioned by pulling on that proximal mandrel end so as to compress the spring where the hooked mandrel tip engages the spring coils and thereby causing the distal end of the expandable element to temporarily deflect from an axial orientation for as long as the mandrel is axially tensioned;
• and,
• (w) the assembly additionally comprises a mandrel element that extends from a proximal end of the assembly, through the catheter shaft, and into the expandable element, wherein at least the portion of the mandrel inside the expandable element tapers to a flattened distal end that terminates in an unbonded angled or hooked mandrel tip at a location proximate to the distal end of the balloon portion, and additionally comprising an elongated spring element with spring coils that surround the mandrel beginning at a location proximal of the expandable element and extending into and through the expandable element to a distal tip of the expandable element where the distal end of the spring is bonded, and furthermore wherein the hooked mandrel tip engages one or more of the spring coils, and also comprising a mandrel tensioning assembly consisting of two threadably-engaged mandrel tensioning elements at the proximal end of the catheter/expandable element assembly whereby the threadably-engaged tensioning elements provide an axial channel in which the proximal end of the mandrel can slide such that rotating one tensioning element relative to the other causes one of the tensioning elements to move in a proximal direction relative to the second element thereby applying axial tensioning to the mandrel and causing deflection of the hooked mandrel tip and the distal tip of the expandable element as long as the axial tensioning is applied;
• the method comprising the steps of:
• (A) inserting at least the expandable element portion of the assembly through the interior of a previously-placed 11-gauge or smaller diameter cannula to position the expandable element in the interior of a vertebral bone;
• (B) inflating the balloon portion of the expandable element inside the vertebral structure to a size and/or inflation pressure and for a time sufficient to complete a vertebral treatment;
• (C) deflating the balloon portion of the expandable element;
• and (D) withdrawing the expandable element including the deflated balloon portion of the assembly through the interior of the 11-gauge or smaller diameter cannula.