Remote position control for surgical apparatus

A system for performing a minimally invasive surgical procedure includes a cannula, a surgical instrument for use through the cannula, and a remote positioning system to adjust the relative position between the surgical instrument and the cannula. By allowing a physician to perform the minimally invasive surgical procedure at a distance from the patient, the remote positioning system minimizes the radiation exposure of the physician while still providing accurate control over the procedure.

FIELD OF THE INVENTION

The invention relates to a system and method for performing a surgical procedure, and in particular, to a medical kit or system that includes a depth control mechanism that can be operated remotely.

BACKGROUND OF THE INVENTION

A minimally invasive procedure (sometimes referred to as a percutaneous procedure) is a medical procedure that is performed through the skin or an anatomical opening. In contrast to an open procedure for the same purpose, a minimally invasive procedure will generally be less traumatic to the patient and result in a reduced recovery period.

For example, for many individuals in our aging world population, undiagnosed and/or untreatable bone strength losses have weakened these individuals' bones to a point that even normal daily activities pose a significant threat of fracture. In one common scenario, when the bones of the spine are sufficiently weakened, the compressive forces in the spine can cause fracture and/or deformation of the vertebral bodies. For sufficiently weakened bone, even normal daily activities like walking down steps or carrying groceries can cause a collapse of one or more spinal bones. A fracture of the vertebral body in this manner is typically referred to as a vertebral compression fracture. Other commonly occurring fractures resulting from weakened bones can include hip, wrist, knee and ankle fractures, to name a few.

Fractures such as vertebral compression fractures often result in episodes of pain that are chronic and intense. Aside from the pain caused by the fracture itself, the involvement of the spinal column can result in pinched and/or damaged nerves, causing paralysis, loss of function, and intense pain which radiates throughout the patient's body. Even where nerves are not affected, however, the intense pain associated with all types of fractures is debilitating, resulting in a great deal of stress, impaired mobility and other long-term consequences. For example, progressive spinal fractures can, over time, cause serious deformation of the spine (“kyphosis”), giving an individual a hunched-back appearance, and can also result in significantly reduced lung capacity and increased mortality.

Until recently, treatment options for vertebral compression fractures, as well as other serious fractures and/or losses in bone strength, were extremely limited—mainly pain management with strong oral or intravenous medications, reduced activity, bracing and/or radiation therapy, all with mediocre results. Because patients with these problems are typically older, and often suffer from various other significant health complications, many of these individuals are unable to tolerate invasive surgery. In addition, to curb further loss of bone strength, many patients are given hormones and/or vitamin/mineral supplements—again with mediocre results and often with significant side effects.

In an effort to more effectively and directly treat vertebral compression fractures, minimally invasive techniques such as vertebroplasty and, subsequently, kyphoplasty, have been developed. Vertebroplasty involves the injection of a flowable bone filler material, usually polymethylmethacrylate (PMMA—commonly known as bone cement), into a fractured, weakened, or diseased vertebral body. Shortly after injection, the liquid filling material hardens or polymerizes, desirably supporting the vertebral body internally, alleviating pain and preventing further collapse of the injected vertebral body.

Because the liquid bone cement naturally follows the path of least resistance within bone, and because the small-diameter needles used to deliver bone cement in vertebroplasty procedure require either high delivery pressures and/or less viscous bone cements, ensuring that the bone cement remains within the already compromised vertebral body is a significant concern in vertebroplasty procedures. Kyphoplasty addresses this issue by first creating a cavity within the vertebral body (e.g., with an inflatable balloon) and then filling that cavity with bone filler material. The cavity provides a natural containment region that minimizes the risk of bone filler material escape from the vertebral body. An additional benefit of kyphoplasty is that the creation of the cavity can also restore the original height of the vertebral body, further enhancing the benefit of the procedure.

In both vertebroplasty and kyphoplasty, as with most minimally invasive procedures, x-ray fluoroscopy is used to allow the surgeon to visualize the procedural actions being performed within the patient. Unfortunately, due to the constrained access requirements of minimally invasive procedures, tools associated with such procedures have typically been designed to be manipulated in close proximity to the actual access location to the patient's body. Therefore, the surgeon performing a minimally invasive procedure can be exposed to the radiation field from the fluoroscopy system. For a surgeon performing a large number of procedures, the cumulative radiation exposure from those procedures can be significant.

Accordingly, it is desirable to provide surgical tools and techniques that minimize the radiation exposure to a surgeon.

SUMMARY OF THE INVENTION

By incorporating remotely activated position control capabilities, a minimally invasive surgical system can be used to effectively perform a minimally invasive surgical procedure while allowing the surgeon to remain outside the radiation field.

In one embodiment, a system for performing a minimally invasive surgical procedure can include a cannula, a surgical instrument (e.g., an inflatable bone tamp, a mechanical cavity creation device, a bone filler material delivery nozzle, etc.) sized to fit through the cannula, and a positioning system for controlling the relative positioning of the surgical instrument with respect to the cannula. The positioning system can include a positioning mechanism that can be coupled to the cannula and surgical instrument, and a remote position controller for controlling the positioning mechanism.

In various embodiments, the system can further include an actuation system for the surgical instrument (e.g., an inflation syringe for an inflatable bone tamp, a remote actuator for a mechanical cavity creation device, a hydraulic pump to cause bone filler material to be delivered via the nozzle, etc.). In various other embodiments, the system can further include additional tools (e.g., introducer needles, guide wires, obturators, drills, etc.) for use in performing the minimally invasive surgical procedure. In various other embodiments, the system can further include instructions for use describing the use of the system.

In various embodiments, the positioning mechanism can include a fixed element that can be coupled to the cannula and an articulating element that can be coupled to the surgical instrument, with the articulating element being coupled to the fixed element by a hinge, a linkage, a living hinge, an elastic element, a linear actuator, a linear guide, a bearing, a lead screw, a hydraulic or pneumatic cylinder, or any other mechanism that enables relative motion between the articulating element and the fixed element. The remote position controller can communicate with positioning mechanism via a communication path (e.g., a cable, rod, linkage, wire (for physical input), wire (for analog or digital input), fiber, wireless link, or any other path for conveying input at remote position controller to positioning mechanism).

In various embodiments, the communication path can be a jacketed cable (e.g., a push-pull cable) that includes an outer jacket having a distal end coupled to the fixed element and an inner cable having a distal end coupled to the articulating element (or vice versa). By moving the inner cable relative to the outer jacket, the relative position of the articulating element (and hence the surgical instrument) can be adjusted relative to the fixed element (and hence the cannula). This positioning can be continuously variable, or can have discrete positional stops to define specific positioning configurations for the surgical instrument and the cannula. In various embodiments, the remote position controller can include a lever, dial/spool, or threaded element for moving the inner cable relative to the outer jacket.

In various other embodiments, the positioning mechanism can further include a biasing element or mechanism (e.g., a spring or other resilient element) that biases the articulating element towards a default position relative to the cannula. In some embodiments, this biasing element can cause the surgical instrument to be fully retracted into the cannula when a specific extension signal is not being provided by the remote position controller.

In various other embodiments, the surgical instrument can be a nozzle for delivering bone filler material, and the system can further include a hydraulic pump to drive the bone filler material through the nozzle, and a second hydraulic line from the hydraulic pump can be used to provide the control signal to the positioning mechanism. The common hydraulic pressure can then be used to retract the nozzle towards the cannula as the bone filler material is dispensed from the nozzle, thereby allowing the nozzle to remain clear of the deposited bone filler material.

In another embodiment, a method for performing a minimally invasive surgical procedure can include placing a cannula in a patient to define an access path to a target surgical location, providing a surgical instrument in the cannula, providing a position control mechanism coupled to the cannula and to the surgical instrument, and remotely controlling the position control mechanism to adjust the position of the surgical instrument relative to the cannula.

In one embodiment, remotely controlling the positioning mechanism can be accomplished by moving the proximal end of inner cable relative to a jacket surrounding the inner cable, with the distal end of the inner cable being coupled to an articulating element in the positioning mechanism coupled to the surgical instrument, and the distal end of the jacket being coupled to a fixed element of the positioning mechanism coupled to the cannula.

In other embodiments of the method for performing the minimally invasive surgical procedure, the surgical instrument can be a nozzle for delivering bone filling material to the target surgical location, and adjusting the position of the surgical instrument relative to the cannula can include retracting the nozzle towards the cannula as it dispenses the bone filling material, or moving the nozzle to a location in the target surgical location (e.g., in the center of a cavity formed within the cancellous bone of a vertebra) and maintaining that position as the nozzle dispenses the bone filler material.

In another embodiment, a nozzle for delivering bone filler material to a target surgical location can include a valve at a distal tip of the nozzle to selectively close off the nozzle opening. In one embodiment, the valve can include a stopper sized to cover the opening at the distal tip of the nozzle, and a cable or rod running through the nozzle to pull the stopper against the distal tip of the nozzle. In one embodiment, the cable/rod can be spring loaded to pull the stopper against the distal tip of the nozzle (i.e., a normally closed valve).

As will be realized by those of skilled in the art, many different embodiments of an introducer/guide pin device, systems, kits, and/or methods of using an introducer/guide pin device according to the present invention are possible. Additional uses, advantages, and features of the invention are set forth in the illustrative embodiments discussed in the detailed description herein and will become more apparent to those skilled in the art upon examination of the following.

DETAILED DESCRIPTION

By incorporating remotely activated position control capabilities, a minimally invasive surgical system can be used to effectively perform a minimally invasive surgical procedure while allowing the surgeon to remain outside the radiation field.

FIG. 1shows a system100of functional instruments that can be used to perform a minimally invasive surgical procedure. In various embodiments, system100can comprise a kit providing a prepackaged set of instruments for performing the surgical procedure.

System100includes a cannula110and a surgical instrument120that is sized to perform a percutaneous procedure through a lumen111of cannula110. System100further includes a positioning mechanism150that can be coupled to cannula110and surgical instrument120, and a remote position controller160that directs positioning mechanism150to adjust the position of surgical instrument120relative to cannula110. Note that according to various embodiments of the invention, positioning mechanism150, remote position controller160, cannula110, and surgical instrument120can be part of a single kit, or can be grouped in any combination of elements (e.g., cannula110and surgical instrument120packaged together, with positioning mechanism150and remote position controller160packaged separately).

In various embodiments, remote position controller160can control positioning mechanism150via direct physical manipulation (e.g., using a cable, wire, linkage, tube, or any other mechanical (including hydraulic) connection), via non-physical control signals (e.g., electrical, optical, magnetic, or other signals transmitted either over a physical path such as a wire or fiber, or wirelessly), or a combination of the two. By enabling remote position control of surgical instrument120, positioning mechanism150and remote position controller160beneficially allow a percutaneous procedure to be performed by a physician outside of the radiation field used for procedure visualization.

Note that as used herein, “remotely controlling” or “remote control” refers to controlling inputs being applied at some distance from the object being controlled. For example, grasping a surgical instrument by hand and moving it within a cannula is not “remote control”, but a long cable or rod coupled to the surgical instrument and/or cannula that can adjust the relative position of the two does provide “remote control”. Preferably, such remote control is provided via a flexible signal path (e.g., a flexible cable or wire or wireless link), to allow the physician maximum freedom of motion during use.

In various other embodiments, system100can further include an optional actuation mechanism130for deploying or activating surgical instrument120, and an optional remote actuation controller140to enable remote control over surgical instrument120. Just as remote position controller160enables positioning of surgical instrument120from outside the procedure radiation field, remote actuation controller140and/or actuation mechanism130can allow the physician to perform the procedure while remaining outside the radiation field.

In one embodiment, surgical instrument120can be a device for creating a cavity in cancellous bone during a kyphoplasty or other bone-reinforcing procedure. For example, surgical instrument120could be an inflatable bone tamp, mechanical void creation device (e.g., expandable structure, cutting element(s), etc.), or a device for creating a cavity in bone by any other means (e.g., heat, ultrasound, radio frequency energy, etc.). Positioning mechanism150could attach to surgical instrument120and cannula110, and the extension of the distal end122of surgical instrument120beyond the distal tip112of cannula110could be controlled by remote position control160. In this manner, system100could enable targeted cavity formation within cancellous bone by remote positioning and/or movement of surgical instrument120.

For example, if surgical instrument120is a inflatable bone tamp (e.g., a balloon catheter with an inflatable balloon configured to compress cancellous bone and apply a lifting force to the endplates of a vertebral body), actuation mechanism130could be an inflation syringe with a length of tubing or other fluid conveyance channel in fluid communication with the inflatable bone tamp, and actuation control140could be a handle, knob, or trigger on the inflation syringe to cause inflation fluid (e.g., air or saline solution) to be expressed from the syringe. The inflation fluid would then be carried by the tubing into the inflatable bone tamp to inflate the inflatable bone tamp and form a cavity in cancellous bone. In this arrangement, surgical instrument (inflatable bone tamp)120could be positioned by remote position controller160, and actuated (inflated/deflated) by actuation controller140, all from outside the fluoroscopic visualization field, thereby minimizing the radiation exposure for the physician.

Similarly, if surgical instrument120is a non-balloon void creation device (i.e., mechanical structure or energy delivery), actuation mechanism130could be a deployment, triggering, release, or other mechanism/circuit for deploying/activating the void creation device, activated by actuation controller140. Instead of tubing or the like as described with respect to the previous example, in this case the actuation control signals could be conveyed via wire (electrical), mechanical cable, linkage, wireless protocol, or any other means that would allow the physician to remotely control the operation of surgical instrument120. In this manner, the physician would once again be able to position (relative to cannula110) and actuate surgical instrument120(via remote position controller160and actuation controller140, respectively) from outside the fluoroscopic radiation field.

In another embodiment, surgical instrument120could be a device for delivering bone filler material to the interior of a vertebral body (e.g., for a vertebroplasty or kyphoplasty procedure) or any other bone (e.g., for treating a long bone or calcaneus fracture). Surgical instrument120could be a delivery nozzle/needle that gains access to the vertebral body through cannula110, and is positioned relative to cannula110by positioning mechanism150and remote position controller160. The bone filler material could then be dispensed from the nozzle/needle at the desired location within the vertebral body by actuation mechanism130(e.g., a plunger) in response to actuation controller140(e.g., a trigger, knob, hydraulic pump, linkage, or any other system for controlling actuation mechanism130. Note that the above-described embodiments are exemplary, and any number of other surgical instruments usable with a remote depth control system will be readily apparent.

Note further that system100can include any number of additional tools190, such as introducer needles/guide wires, drills, obturators, handles, among others. System100can also include optional instructions for use180that describe the proper usage of the tools in system100(e.g., as described below with respect toFIG. 3).

FIGS. 2(A)-2(I)depict an exemplary minimally invasive surgical procedure using a remote positioning system.FIG. 2(A)shows a portion of a human vertebral column, with vertebrae201,202, and203. Vertebra202has collapsed due to a vertebral compression fracture (VCF)202-F that could be the result of osteoporosis or cancer-related weakening of the bone. The abnormal curvature of the spine caused by VCF202-F can lead to severe pain and further fracturing of adjacent vertebral bodies.

One treatment for this type of fracture is to perform a minimally invasive procedure in which a reinforcing bone filler material is injected into the fractured vertebra, either directly into the fractured region (vertebroplasty) or into a cavity created beforehand in the cancellous bone structure (kyphoplasty). Kyphoplasty is often a preferred technique due to the potential height restoration that can be achieved during the cavity creation phase of the procedure.

FIG. 2(B)shows a cannula210being positioned next to the target surgical location, which in this case is the cancellous bone structure within fractured vertebra202. In this manner, a percutaneous path to vertebra202is provided via an interior lumen211of cannula210. Typically, cannula210is docked against the exterior wall of the vertebral body (using either a transpedicular or extrapedicular approach) using a guide needle and/or dissector, after which a drill or other access tool (not shown) is used to create a path further into the cancellous bone202-C of vertebra202. However, any other method of cannula placement can be used to position cannula210.

Then inFIG. 2(C), a surgical instrument220-1(in this case an inflatable bone tamp) is placed in cannula220. Inflatable bone tamp220-1includes a shaft221-1and an expandable structure223(e.g., a balloon) at the distal end of shaft221-1. Inflatable bone tamp220-1is coupled to an actuation mechanism230-1(in this case an inflation syringe) by a flexible tube235-1. Inflation syringe230-1includes an actuation controller240-1(in this case a knob or handle) for causing inflation fluid to be delivered to expandable structure223via flexible tube235-1and shaft221-1of inflatable bone tamp220-1.

Expandable structure223, when in an unexpanded state as depicted inFIG. 2(C), is sized to fit within interior lumen211of cannula210, as is shaft221-1of inflatable bone tamp220-1. Therefore, inflatable bone tamp220-1can slidably move within lumen211. A positioning mechanism250-1is coupled to cannula210and inflatable bone tamp220-1to control a distance D1that inflatable bone tamp220-1extends beyond a distal tip212of cannula210in response to input received at a remote position controller260-1. In this manner, a physician can use remote position controller260-1to adjust the placement of expandable structure223within vertebra202from a location outside of the fluoroscopic field used to visualize the procedure site.

As noted above with respect toFIG. 1, positioning mechanism250-1can be any mechanism/construction that can move inflatable bone tamp220-1relative to cannula210. For instance, positioning mechanism220-1can include a fixed element251-1coupled to cannula210, and an articulating element252-1coupled to inflatable bone tamp220-1. In various embodiments, positioning mechanism220-1can be coupled to cannula210and inflatable bone tamp220-1by clips, clamps, snaps, screws, hooks, or any other engaging features and/or fastening device. Note that while articulating element252-1is depicted as being coupled to fixed element251-1via a sliding interface (e.g., a linear guide or linear actuator), in various other embodiments, articulating element252-1can be coupled to fixed element251-1by a hinge (including living hinge), lever, linkage, elastic element, pulley system, bearing, solenoid, or any other structure or mechanism that would allow relative movement between the two.

Likewise, remote position controller260-1and the control path265-1by which it controls positioning mechanism250-1can take any form/construction that can provide input from position controller260-1to positioning mechanism250-1. For example, in certain embodiments, control path265-1could be a jacketed cable (i.e., a cable capable of transmitting axial loads surrounded by a flexible conduit, such as a push-pull cable) coupled between an adjustment mechanism in remote position controller260-1and articulating element252-1. In other embodiments, control path265-1could be a hydraulic line for transmitting a displacement distance at remote position controller260-1to articulating element252-1. In other embodiments, control path265-1could be a wired or wireless link for transmitting either analog or digital control signals from remote position controller260-1to positioning mechanism250-1(e.g., remote position controller260-1could provide an “extend” or “retract” signal to a linear actuator in positioning mechanism250-1via a wiring harness). Various other embodiments will be readily apparent.

Note also that remote position controller260-1and actuation mechanism230-1/actuation controller240-1are shown as being distinct structures for exemplary purposes only. In various other embodiments, position controller260-1can be integrated with actuation mechanism230-1and/or actuation controller240-1.

Once expandable structure223has been positioned at a desired distance D1from the tip212of cannula210by positioning mechanism250-1and remote position controller260-1, handle240-1of inflation syringe230-1is used to deliver inflation fluid from inflation syringe230-1, through flexible tube235-1, and into inflatable bone tamp220-1, thereby inflating expandable structure223, as shown inFIG. 2(D). The expansion of expandable structure222compresses the surrounding cancellous bone202-C to create a well-defined cavity within fractured vertebra202, and can also restore some or all of the original height of the vertebral body.

Note that although the cavity creation process described above is performed by sequentially positioning and then expanding expandable structure223for exemplary purposes, in various other embodiments the positioning and expanding operations could be performed multiple times at multiple locations in the vertebral body. In other embodiments, and particularly if structure223is a mechanical void creation instrument (e.g., a cutting/compressing element(s) or structure(s), stent, whisk, rasp, osteotome, or coring element, among others) the positioning and expanding operations could be performed simultaneously. In other embodiments, cavity creation in the vertebral body can be performed/supplemented by positioning mechanism250-1actually moving the mechanical void creation element within the vertebral body to manipulate the cancellous bone (e.g., scraping, cutting, coring, displacing, etc.).

Upon completion of the above-described operations, inflatable bone tamp220-1and the related actuation and positioning accessories can be removed, leaving behind a cavity204in the cancellous bone202-C of vertebra202. Note that cannula210remains docked with vertebra202to provide an access path for the subsequent operations described in greater detail below.

FIG. 2(F)shows a surgical instrument220-2(in this case a bone filler material delivery nozzle) placed within cannula210, with a shaft221-2of nozzle220-2passing through lumen211of cannula210. A cartridge223is attached to nozzle220-2to provide a reservoir of bone filler material (e.g., bone cement) for delivery via nozzle220-2, and is coupled to an actuation mechanism230-2(in this case a hydraulic pump) by a hydraulic line235-2. Hydraulic pump230-2includes a trigger240-2to increase hydraulic pressure through hydraulic line235-2to cause bone filler material229to be expressed from cartridge223through nozzle220-2into cavity204of vertebra202.

Meanwhile, a positioning mechanism250-2is coupled to cannula210and cement delivery nozzle220-2to control a distance D2that cement delivery nozzle220-2extends beyond the distal tip212of cannula210in response to input from a remote position controller260-2. Therefore, a physician can use remote position controller260-2to adjust the placement of expandable structure223within vertebra202from a location outside of the fluoroscopic field used to visualize the procedure site.

As noted above with respect toFIG. 2(C), positioning mechanism250-2can be any mechanism/construction that can move nozzle220-2relative to cannula210. For instance, positioning mechanism220-2can include a fixed element251-2coupled to cannula210, and an articulating element252-2coupled to nozzle220-2. In various embodiments, positioning mechanism220-2can be coupled to cannula210and cement delivery nozzle220-2by clips, clamps, snaps, screws, hooks, or any other engaging features and/or fastening device. Note that while articulating element252-2is depicted as being coupled to fixed element251-2by a sliding interface (e.g., a linear guide or linear actuator), in various other embodiments, articulating element252-2can be coupled to fixed element251-2by a hinge (including living hinge), lever, linkage, elastic element, pulley system, bearing, solenoid, or any other structure or mechanism that would allow relative movement between the two.

Likewise, remote position controller260-2and the control path265-2by which it controls positioning mechanism250-2can take any form/construction that can provide input from position controller260-2to positioning mechanism250-2. In some embodiments, control path265-2could be a jacketed cable (i.e., a cable capable of transmitting axial loads surrounded by a flexible conduit, such as a push-pull cable) coupled between an adjustment mechanism in remote position controller260-2and articulating element252-2. Movement of the inner cable relative to the outer cable at the proximal end of the jacketed cable (i.e., at remote position controller260-2) is translated to the distal end of the jacketed cable, and then to positioning mechanism250-2. In other embodiments, control path265-2could be a wired or wireless link for transmitting either analog or digital control signals from remote position controller260-2to positioning mechanism250-2(e.g., remote position controller260-2could provide an “extend” or “retract” signal to a linear actuator in positioning mechanism250-2via a wiring harness).

For example, as shown inFIG. 4(A), control path265-2can include a cable266within an outer jacket267(e.g., a push-pull cable). Outer jacket267is connected between a housing260-H of position controller260-2and fixed element251-2, and cable266is connected between articulating element252-2and a lever (adjustment mechanism)261in position controller260-2(lever261is movable with respect to housing260-H). Therefore, moving lever261pulls/pushes cable266within outer jacket267to change the position of articulating element252-2relative to fixed element251-2. Note that in various other embodiments, outer jacket267could be connected to articulating element252-2and cable266could be connected to articulating element252-2. Lever261could be continuously movable, or could have two or more fixed positions, depending on whether continuously variable position control or discrete position settings, respectively, is desired.

In another embodiment, an optional biasing element (e.g., a spring254) can apply a biasing force to move articulating element252-2and fixed element251-2towards a default spacing when no force is being applied to lever261. This in turn defines a default position of the surgical instrument relative to the cannula.

In another embodiment, as shown inFIG. 4(B), lever261inFIG. 4(A)can be replaced with a dial (adjustment mechanism)262-D for winding/unwinding cable266around a spool262-S. This winding/unwinding action then changes the position of articulating element252-2relative to fixed element251-2. An optional biasing element (e.g., a spring254) can apply a biasing force to move articulating element252-2and fixed element251-2towards a default spacing when no force is being applied to dial262-D. In one embodiment, spool262-S or dial262-D can include one or more engagement features (e.g., teeth, detents, grooves, ridges, or bumps, among others), and position controller260-2can include a latch263that can selectively engage the engagement features to lock spool262-S/dial262-D in a fixed position at specific positional “stop points”. In various other embodiments, dial262-D could be freely rotatable to provide continuously variable position control.

In another embodiment, as shown inFIG. 4(C), lever261inFIG. 4(A)or dial262-S inFIG. 4(B)can be replaced with a threaded element (adjustment mechanism)268connected to cable266. Threads269on threaded element268mate with threads264on housing260-H of position controller260-2, so that turning threaded element268pulls/pushes cable266within outer jacket267to change the position of articulating element252-2relative to fixed element251-2. An optional biasing element (e.g., a spring254) can apply a biasing force to move articulating element252-2and fixed element251-2towards a default spacing when no force is being applied to threaded element268(depending on the frictional resistance between threads269and264). Various other adjustment mechanisms for moving cable266relative to outer jacket267will be readily apparent.

Returning toFIG. 2(F), in other embodiments, control path265-2could be a hydraulic line for transmitting a displacement distance at remote position controller260-2to articulating element252-2. For example, an optional hydraulic line265-3could be provided from the same hydraulic pump used to actuate surgical instrument220-2(or a different hydraulic pump). In one embodiment, the hydraulic pressure that causes nozzle220-2to dispense filler material229into cavity204can also cause positioning mechanism250-2to retract nozzle220-2from cavity204, thereby always keeping nozzle220-2out of the mass of dispensed filler material229. Various other embodiments will be readily apparent.

As shown inFIG. 2(G), in one embodiment, remote position controller260-2and positioning mechanism250-2can draw nozzle220-2further into cannula210(i.e., decrease distance D2) as actuator230-2causes cartridge223to dispense filler material229into cavity204via nozzle220-2. This can be particularly beneficial when placing bone filler material within longer bones (e.g., when treating fractures of arm or leg bones such as the humerus or femur, respectively, the dispensing nozzle can be retracted as the dispensed bone filler material fills an elongated cavity within the bone, thereby ensuring a consistent fill while minimizing the possibility of the nozzle being cemented into the bone).

Note that in various other embodiments, positioning mechanism250-2can be used to place the tip222-2of nozzle220-2in a specific location (or several discrete locations) as filler material229is dispensed. For example, in one embodiment, the tip222-2of nozzle220-2could be placed in the center of cavity204during the entire fill process.

Once filling is complete, nozzle220-2can be fully withdrawn into cannula210, as shown inFIG. 2(H). In some embodiments, positioning mechanism250-2can extend/retract nozzle220-2one or more times after dispensing is complete to tamp any residual/stray bone filler material229into vertebra202. This tamping operation ensures that no bone filler material remains in cannula210, and can also minimize the risk of bone filler material being placed anywhere except within vertebra202.

Note that in some embodiments, it can be desirable to have nozzle220-2be withdrawn into cannula210as a default configuration. Specifically, in the absence of a specific extension command from remote position controller260-2, positioning mechanism250-2would pull the tip222-2of nozzle220-2back in to cannula210. Doing so could prevent nozzle220-2from becoming cemented in to vertebral body202by the bone filler material229(e.g., if the physician inadvertently leaves nozzle220-2extended into the mass of deposited bone filler material229as it hardens. In one embodiment, this functionality could be provided by a resilient element (e.g., a spring)253-2that biases the proximal end225-2of surgical instrument220-2away from the proximal end215of cannula210. In various other embodiments, remote position controller260-2could provide a default control signal to positioning mechanism250-2to withdraw nozzle220-2. Various other embodiments will be readily apparent.

In one embodiment, nozzle220-2can include a valve at distal tip222-2, as shown inFIGS. 5(A) and 5(B). A cable (or rod)226runs through the interior of nozzle220-2and is attached to a stopper225. InFIG. 5(A), stopper225is extended beyond the distal tip222-2of nozzle220-2. Because the diameter of cable226is less than the inner diameter of nozzle220-2, the bone filler material229is able to flow around cable226, past stopper225, and into cavity204. Once a desired amount of filling material229is dispensed, cable226can be moved proximally to pull stopper225against tip222-2of nozzle220-2. This not only stops the flow of filler material229, but also breaks any connection between the deposited filler material and the filler material remaining in nozzle220-2.

In one embodiment, cable226can be spring loaded, such that stopper225is normally pulled against tip222-2of nozzle, but positive pressure from bone filler material229in nozzle220-2pushes stopper225away from tip222-2. In another embodiment, cable226can be coupled to a reciprocating pumping mechanism for filler material229, such that on every pumping stroke stopper225is moved away from tip222-2, and on every non-pumping stroke (e.g., refill or suction), stopper225is seated against tip222-2. Note that the tip valve formed by stopper225and cable226can be used in any nozzle for dispensing material into a target location, and need not be used with a nozzle that is part of a system that includes remote positioning control.

Once the filling operation is complete, nozzle220-2and cannula210are removed from vertebra202(and the patient's body) as shown inFIG. 2(I). Upon hardening, bone filler material229provides structural support for vertebra202, thereby substantially restoring the structural integrity and proper musculoskeletal alignment of the spine. In this manner, the pain and attendant side effects of a vertebral compression fracture can be addressed by a minimally invasive kyphoplasty procedure.

FIG. 3shows a flow diagram of a process for performing a minimally invasive surgical procedure using the system of FIGS.1and2(A)-2(I). In a PLACE CANNULA step310, a cannula is placed in a patient such as described with respect toFIGS. 1 and 2(B), thereby creating an access path through which the surgical procedure can be performed. In various embodiments, step310can involve additional steps, such as inserting a guide needle to assist with placement of the cannula, and/or using a drill/obturator to extend the access path provided by the cannula.

Next, in an INSERT SURGICAL INSTRUMENT step320, a surgical instrument is placed within the cannula. In various embodiments, the surgical instrument could be an inflatable bone tamp or a bone filler material delivery nozzle, as described above with respect toFIGS. 2(C) and 2(F), respectively. In various other embodiments, the surgical instrument could be any instrument for performing a surgical procedure through a cannula.

In an ATTACH REMOTE POSITIONING SYSTEM step330, a positioning mechanism is attached to the cannula and the surgical instrument, such as described with respect toFIGS. 1,2(C) and2(F). Note that in some embodiments, the positioning mechanism can be pre-attached to the cannula and/or surgical instrument, in which case step330can be eliminated. Then, in a REMOTELY POSITION SURGICAL INSTRUMENT step340, a remote position controller such as described with respect toFIGS. 1,2(C),2(F), and2(G) is used to extend the surgical instrument out the distal end of the cannula to a desired location.

In an ACTUATE SURGICAL INSTRUMENT step350, the surgical instrument is used to perform the surgical procedure (e.g., cavity creation within cancellous bone or bone filler material delivery, as described in FIGS.2(D) and2(F)-2(H), respectively). Note that in various embodiments, steps340and350can be performed simultaneously, or multiple times (as indicated by the dotted line arrow).

The surgical instrument and related apparatus (e.g., positioning system, actuating system) are then removed from the cannula in a REMOVE SURGICAL INSTRUMENT step360. Optionally, a new surgical instrument can then be inserted into the cannula to perform another portion of the surgical procedure, as indicated by the dotted arrow. Finally, the cannula is removed from the patient in a REMOVE CANNULA step370to complete the surgical procedure.

While various embodiments of the invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Where methods and steps described above indicate certain events occurring in certain order, those of ordinary skill in the art having the benefit of this disclosure would recognize that the ordering of certain steps may be modified and that such modifications are in accordance with the variations of the invention. Additionally, certain steps may be performed concurrently in a parallel process when possible, as well as performed sequentially as described above. Thus, the breadth and scope of the invention should not be limited by any of the above-described embodiments, but should be defined only in accordance with the following claims and their equivalents. While the invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood that various changes in form and details may be made.