Abstract:
The present invention provides an inflatable retractor for providing access to a surgical site, such as a patient&#39;s spine, during a surgical process. When used in spinal surgery, the inflatable retractor allows a surgeon to operate on one or more spinal levels. The inflatable retractor includes an inflatable body defining a central cavity, wherein the body is flaccid in a non-inflated state and increasingly rigid in an inflated state. The inflatable retractor is inserted into an incision in a deflated, or partially inflated, state and then inflated once the retractor is in position. The inflation of the retractor retracts skin and muscle from the surgical site, allowing adequate visualization of the surgical site and forms a passage providing access for implants and surgical instruments to pass through the retractor and into the surgical site.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a device and method for accessing a surgical site during surgery, such as spinal surgery. More particularly, the present invention relates to a device and method for retracting tissue surrounding a surgical site during a surgery. 
       BACKGROUND OF THE INVENTION 
       [0002]    Spinal retraction systems are used in spinal surgery to provide access to a patient&#39;s spine by retracting and holding back tissue from a targeted surgical site beneath the skin. Current spinal retraction systems are rigid and therefore have difficulty conforming to patient anatomy. The rigid nature of such spinal retraction systems may also lead to increased danger to skin, nerves, vessels or muscle tissue, and often an inability to get good muscle retraction at a desired location. Furthermore, the rigid retractor requires a sizeable incision for insertion of the retractor into a patient. In addition, rigid retractors require a bed-mounted arm to hold the retractor in place relative to the patient&#39;s body. Such bed-mounted arms can provide an obstruction to the operating field of the surgeon and if the arm is inadvertently bumped by the surgeon, the secured retractor may be moved or dislodged. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention provides an inflatable retractor for providing access to a surgical site, such as a patient&#39;s spine, during a surgical process. When used in spinal surgery, the inflatable retractor allows a surgeon to operate on one or more spinal levels. The inflatable retractor includes an inflatable body defining a central cavity therethrough, wherein the body is flaccid in a non-inflated state and increasingly rigid in an inflated state. The inflatable retractor is inserted into an incision in a deflated state and then inflated once the retractor is in position. The inflation of the retractor retracts skin and muscle from the surgical site, allowing adequate visualization of the surgical site and forms a passage providing access for implants and surgical instruments to pass through the retractor and into the surgical site. 
         [0004]    In accordance with a first aspect of the present invention, an inflatable retractor for retracting tissues in an incision for a surgical site is provided. The inflatable retractor comprises an inflatable body defining a central cavity therethrough, wherein the body is flaccid in a non-inflated state and increasingly rigid in an inflated state. 
         [0005]    In one embodiment, the inflatable retractor further comprises a valve functional to maintain an inflating pressure in the inflatable body. The valve may also be used to release inflating pressure in the inflatable body. 
         [0006]    In one embodiment, the inflatable body is generally cylindrical in shape. Thus when inflated, the retractor forms a tube having a central bore proving access to a surgical site. 
         [0007]    In one embodiment, the inflatable body is generally conical in shape. Thus when inflated, the retractor forms a funnel having a central bore that is wider at one end then the other. 
         [0008]    In one embodiment, the inflatable body is helical in shape and configured to be coiled upon itself to define a passage for accessing a patient. Thus when inflated, the retractor can be shaped to conform as needed to provide access to the surgical site. 
         [0009]    In embodiments wherein the inflatable body has a general shape, support structures, such as shape memory material support structures, may be used to maintain the shape of the inflatable retractor. The retractor may also conform to the surrounding anatomy while still retracting tissue. The retractor may also have distal protrusions for retracting tissue and minimizing tissue creep. 
         [0010]    In one embodiment, the inflatable retractor further comprises an anchor attached to the inflatable body for anchoring the inflatable body to a body part within the incision. The anchor may comprise, for example, a re-absorbable anchor, a removable biocompatible anchor, or an intermediate anchor, such as a pedicle screw or bolt. 
         [0011]    In accordance with another embodiment, a method is provided for accessing a surgical site in a patient. The method comprises the steps of creating an incision in the patient; inserting a deflated or partially inflated inflatable retractor into the incision in the patient, the inflatable retractor comprising an inflatable body defining a central cavity therethrough, wherein the body is flaccid in a non-inflated state and increasingly rigid in an inflated state; and inflating the inflatable retractor to retract tissue surrounding the incision to create a surgical site. 
         [0012]    In one embodiment, the method further comprises the step of preparing the incision prior to inserting the inflatable retractor. Preparing the incision may include: inserting a guide into the incision, sweeping back muscle and tissue from the surgical site, and finding a target for attaching an inflatable retractor. 
         [0013]    In one embodiment, the step of inserting the inflatable retractor comprises using an instrument to insert the inflatable retractor into the incision. Insertion may also include attaching the inflatable retractor to a target. The retractor may contain radiopaque markers to aid in percutaneous insertion under fluoroscopy. 
         [0014]    In some embodiments, the inflatable retractor is inflated with a gas, liquid, or combination of both. In other embodiments a hardening agent may be used to inflate the retractor that increases the rigidity of the inflated retractor. 
         [0015]    In one embodiment, the method further comprises deflating the retractor after a surgical procedure has been performed and removing the deflated retractor from the incision. 
         [0016]    In accordance with another aspect, a system is provided for retracting tissues in an incision for a surgical site. The system comprises an insertion tool for insertion into the incision at a surgical site; and inflatable retractor configured to be guided to a surgical site by the insertion tool, the inflatable retractor comprising an inflatable body defining a central cavity, wherein the body is flaccid in a non-inflated state and increasingly rigid in an inflated state. 
         [0017]    In one embodiment, the insertion tool comprises a dilator and the inflatable retractor is guided to the surgical site over the dilator. In yet another embodiment, the insertion tool is a guide-wire and the inflatable retractor is guided to the surgical site over the guide-wire. In yet another embodiment the insertion tool comprises a cannula and the inflatable retractor is guided to the surgical site through the cannula 
     
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0018]    The foregoing and other objects, features and advantages of the invention will be apparent from the following description and apparent from the accompanying drawings, in which like reference characters refer to the same parts throughout the different views. The drawings illustrate principles of the invention and, although not to scale, show relative dimensions 
           [0019]      FIG. 1A  illustrates an embodiment of an inflatable surgical retractor of the invention. 
           [0020]      FIG. 1B  illustrates an embodiment of an inflatable retractor filled with a temperature reactive liquid or gas to inflate and deflate the retractor. 
           [0021]      FIG. 2A-2C  illustrates embodiments of a cylindrical shaped inflatable surgical retractor having a number of inflatable chambers. 
           [0022]      FIG. 3A-3D  illustrates embodiments of a conical shaped inflatable surgical retractor having a number of inflatable chambers. 
           [0023]      FIG. 4A-4B  illustrates embodiments of a helical shaped inflatable surgical retractor. 
           [0024]      FIG. 5  illustrates embodiments of a finger shaped inflatable surgical retractor. 
           [0025]      FIG. 6  illustrates a flow diagram for an exemplary embodiment of a method of using an inflatable retractor of the invention. 
           [0026]      FIG. 7A  illustrates an embodiment of a guide and drill used in installing an inflatable retractor of the invention. 
           [0027]      FIG. 7B  illustrates an embodiment of an inserter tool used in installing an inflatable retractor of the invention. 
           [0028]      FIGS. 8A-8B  illustrate another embodiment of a system for installing an inflatable retractor of the present invention. 
           [0029]      FIGS. 9A-9D  illustrate another embodiment of an inflatable retractor of the present invention using a hardening agent. 
           [0030]      FIGS. 10A-10D  illustrate another embodiment of a use of an inflatable retractor of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    The present invention provides an improved surgical device and method for retracting tissue from an incision and providing access to a surgical site in a patient. The inflatable body of the retractor allows the retractor to be inserted in a deflated or semi-inflated state and then inflated in-situ to effect retraction and provide access to the surgical site. Because the retractor is inserted in a non-inflated state, the incision used for insertion does not have to be as large as required to insert traditional retractors. The inflatable body of the retractor also allows the retractor to conform to the tissue and muscle as it retracts the tissue and muscle which causes less trauma to the patient. After the necessary surgical procedure is performed using the inflatable retractor, the retractor may be deflated and removed. 
         [0032]    In one embodiment, shown in  FIG. 1A , an inflatable retractor  100  comprises an inflatable body  110  defining a central cavity  120 , wherein the body  110  is flaccid in a non-inflated state and increasingly rigid in an inflated state. In  FIGS. 1A and 1B  the inflatable retractor  100  is depicted in both an inflated state and a deflated state to illustrate the shape and configuration of the inflatable retractor  100 . 
         [0033]    In certain embodiments, the inflatable body  110  is dimensioned so that the defined cavity  120  provides a passage sized to access the spine of a patient, such as the vertebra. In some such embodiments the inflatable body  110  is dimensioned so the defined cavity  120  may provide a passage for posterior access to the spine of a patient. For example, the defined cavity  120  may have a diameter of 8-40 mm and a length of 30-200 mm. In other such embodiments, the defined cavity  120  may provide a passage for anterior access to the spine. Here, the defined passage may have a diameter of 150 mm and a length of 300 mm. The inflatable body  110  may be dimensioned to add 1-10 mm to the periphery of the defined passage. Other suitable configurations, dimensions, and applications will be apparent to one skilled in the art given the benefit of this disclosure. 
         [0034]    To reduce adverse reactions with a patient when in use the inflatable body  110  may be formed of biocompatible material. Examples of suitable biocompatible materials include, but are not limited to, poly(ethylene terephthalate) and poly(etheretherketone). In some embodiments, a polymer or metal mesh may be embedded in the body  110  to improve puncture resistance. In certain embodiments, the outer surface  140  of the retractor  100  in contact with tissue may be formed of one material while inner surface  150  defining the cavity  120  is formed of another material. Other possible materials and combinations will be apparent to one skilled in the art given the benefit of this disclosure. 
         [0035]    In some embodiments, the inflatable body  110  of the inflatable retractor  100  may be coated or impregnated with a therapeutic agent allowing the inflatable retractor  100  to be used for drug delivery at the surgical site. For example, pain medication, antibiotics, anti-inflammatories, and other medications may be applied to or impregnated in the inflatable body  110 , or applied to the outside of the body  140  and delivered at the incision site by the inflatable body  110 . 
         [0036]    In some embodiments an illuminant can be coupled to the inflatable body  110  to provide illumination at the incision site. In one example, the illuminant may be a luminescent chemical coupled to the interior surface  150  defining the cavity. In one such embodiment, the interior surface  150  is treated with a luminescent chemical. In another such embodiment, inflatable body  110  may be formed of a luminescent material. In another example, the inflatable body  110  may be formed of a translucent material and filled with a luminescent chemical, or the body may be formed of a translucent material and have a provision to attach to a light generating source separate from the retractor. 
         [0037]    In certain other embodiments, the inflatable body  110  of the retractor  100  may include radiopaque markers. These markers aid in the percutaneous insertion of the retractor  100  under fluoroscopy. 
         [0038]    In some embodiments, the inflatable retractor  100  further includes a valve  160  functional to maintain an inflating pressure in the inflatable body  110 . A gas, liquid, or combination of both may be introduced through valve  160  to inflate the inflatable retractor  100 . Suitable inflating mediums include, but are not limited to water, saline solution, air, and the like. In certain embodiments the valve  160  may also be used to release the inflating pressure thereby deflating the inflatable body  110 . In some such embodiments, the retractor  100  may be inflated and deflated multiple times allowing the inflatable retractor  100  to be re-used, or the pressure adjusted interoperatively to relieve pressure on the skin, tissue, and nerves. 
         [0039]    The required inflation pressure depends on the use of the inflatable retractor  100  as well as the type and amount of tissue being retracted. For most applications, a pressure of 80 psi would be suitable to inflate the body  110  and provide retraction. It should be understood that the type of material the inflatable body is formed of as well as the inflation medium may also affect the inflation pressure. 
         [0040]    In some embodiments, the inflatable body  110  may be filled with a temperature sensitive liquid or gas. In one such example, the inflatable body  110  could be filled with a hardening agent, like an epoxy, that sets-up or solidifies and makes the inflated retractor rigid. In one such example, the liquid may be a wax-like material that can be made to harden or expand at a certain temperature to rigidify or inflate the retractor  100  and then re-liquefy by changing the temperature to collapse or deflate the retractor  100 . In the example of a temperature sensitive gas, the gas could expand at certain temperature, such as internal body temperature, to inflate the retractor and contract at another temperature, such as room temperature, to deflate the retractor  100 . An example of this can be seen in  FIG. 1B . Here the retractor  100  is deflated at a first temperature  102 , such as room temperature or a cooled state. As the temperature is increased to a second temperature  104 , the liquid or gas in the body  110  expands to inflate the retractor  100 . Returning the temperature to the first temperature  102  deflates the body. The temperatures at which the retractor  100  may expand or contract may be set as needed by selecting the appropriate gas or liquid with the desired temperature characteristics. The temperature, and thus the inflation, may be controlled by externally applying fluids or gases or other heating or cooling means as needed. Other possible implementations will be apparent to one skilled in the art given the benefit of this disclosure. 
         [0041]    Returning again to  FIG. 1A , in some embodiments, the inflatable retractor  100  may further include a support structure  170  for maintaining the shape of the inflatable body. For example, inflatable body may be a spline or ring  170  of shape memory material, such as Nitinol, that can be collapsed for insertion and then be expanded once the retractor is deployed to help maintain the shape of the inflatable body  110  under load. Other configurations and implementations will be apparent to one skilled in the art given the benefit of this disclosure. 
         [0042]    In some embodiments, the inflatable retractor  100  may further include an anchor  180  attached to the inflatable body  110  for anchoring the inflatable body to a body part within the incision. The anchor  180  may comprise any suitable device such as a screw, pin, wire, or the like for anchoring the inflatable body  110  to a body part. For example, in one embodiment, the anchor  180  comprises a resorbable anchor. Alternatively the anchor  180  may comprise an anchor formed of a bio-compatible non-resorbable material. The anchor  180  may attach directly to the bone or body part. Alternatively, an anchor that is left behind after the retractor is removed and serves a second purpose such as pedicle screws fixed to the pedicle bone and used for supporting instrumented spinal stabilization, may be used to connect an inflatable body  110  to the body part. 
         [0043]    In some embodiments as seen in  FIGS. 2A-C , the inflatable body  210  may be comprised of one or more inflatable chambers  230 . The use of multiple chambers  230  can reduce the likelihood of a puncture causing total deflation of the retractor  200 . For example the multiple chambers  230  can be connected by one-way valves allowing for inflation but keeping the retractor from completely deflating if one chamber  230  is punctured. In  FIGS. 2A-C  the inflatable retractor is depicted in an inflated state to better illustrate the shape and configuration of the inflatable retractor. In the example of  FIGS. 2A and 2B , the multiple chambers  230  form a series of rings around the circumference of the defined cavity  220 . Alternatively, the multiple chambers  230 ′ can be formed along the length of the defined cavity  220  as shown in  FIG. 2C . 
         [0044]    In addition to increased puncture resistance, the curvature of the outer surface  240  of the retractor  200  formed by the multiple chambers  230 ,  230 ′ provides increased surface area traction with the tissue and muscle at the surgical site. This assists in both the retraction of the tissue and muscle by the retractor  200  as well the anchoring or fixation of the retractor  200  at the surgical site. Additionally, this increased surface area spreads the load more evenly on the tissue, reducing areas of high pressures. In some embodiments, the outer surface  240  of the retractor  200  may be textured to further increase traction. In some embodiments, the inflatable retractor  200  may also have distal protrusions for assisting in the retraction of tissue and minimizing tissue creep. 
         [0045]    In the embodiment of the retractor depicted in  FIGS. 1-2C , the inflatable body is cylindrical in shape and defines a cavity through the body which may provide a passage for accessing the patient. Thus, when deployed in a patient, the retractor  100 ,  200  provides an access port from outside of an incision at a proximal end  122 ,  222  of the defined cavity  120 ,  220  to a surgical site at the distal end  124 ,  224  of the defined cavity  120 ,  220 . It should be understood however, that cylindrical is but one possible shape and there are any number of other possible shapes and configurations. 
         [0046]    In another embodiment of an inflatable retractor  300  as shown in  FIGS. 3A-D , the inflatable body  310  is conical in shape and defines a cavity  320  though the body  310  that provided a passage for accessing a patient. Thus, when deployed in a patient, the inflatable retractor  300  provides a body that is larger at the distal end  324  of the defined passage  320  then at the proximal end  322  of the defined cavity  320 .  FIG. 3A  illustrates the inflatable retractor  300  being delivered to a surgical site, i.e. a vertebral body, on the end of an insertion instrument  390 . As with the example in  FIGS. 2A and 2B , the inflatable body  310  in  FIGS. 3A-C  comprises multiple chambers  330  that form a series of rings around the circumference of the defined cavity  320 . As with  FIG. 2C , the multiple chambers  330 ′ of  FIG. 3D  are formed along the length of the defined cavity  320 . 
         [0047]    The conical shape provides some additional benefits when deployed in a patient. One benefit is that the larger opening at the distal end  324  of the cavity  320  provides a larger access area at the surgical site than provided by cylindrical shaped retractor without requiring a larger incision. The flared nature of the conical shaped retractor  300  also assists in the anchoring or fixation of the retractor  300  at a surgical site because the retracted tissue and muscle is displaced in such a way that it creates a partial downward pressure on the retractor walls, rather than only a normal pressure on the walls as would be the case in a cylindrical retractor. 
         [0048]    In another embodiment of the inflatable retractor  400  of the present invention, as shown in  FIGS. 4A and 4B , the inflatable body  410  is helical in shape and configured to be coiled upon itself to define a cavity  420  for accessing a patient. In use, the inflatable body  410  can be inserted in a patient in a deflated or semi-inflated state. One advantage of a helical shape is that the inflatable body  410  can be configured as needed to define a cavity  420  to provide access to a surgical site. Thus, while the helical shape can be configured in a cylindrical shape or conical shape as show in  FIGS. 2A-C  and  3 A-D, it is not limited to a fixed depth or cavity width of the fixed-shaped cylindrical or conical shaped retractors  200 ,  300  of  FIGS. 2A-C  and  3 A-D. 
         [0049]    While the above examples of inflatable retractors depict specific configurations (cylindrical, conical, and helical) it should be understood that the inflatable body of the inflatable retractor can assume any number of possible shapes and configurations. Indeed, the conformable nature of the inflatable body allows it to be configured and used in other applications. An example of this can be seen in  FIG. 5 . 
         [0050]    In  FIG. 5 , the inflatable retractor  500  is configured to mimic a finger. As with the previously described inflatable retractors, the inflatable retractor of  FIG. 5  has an inflatable body  510  defining a cavity  520  for providing access to a patient. In this example, the inflatable body  510  is configured to be generally finger-like in shape. The inflatable retractor may further include a rigid shaft  590  for manually manipulating the inflatable body  510  as it is inserted into the incision. 
         [0051]    In many instances, a surgeon will use a finger inserted into the incision to probe and perform blunt dissection between the tissue and muscles planes of a patient. The soft conforming nature of the inflatable retractor  500  allows the retractor to be used to probe and dissect the tissue and muscle planes in place of a finger. Traditionally, once the probing and separation are performed, the surgeon must insert a dilator, retractor or similar tool into the incision in place of the finger to affect the actual retraction. The advantage of using an inflatable retractor for the probing and separation, is that once the probing and separation are completed the inflatable retractor  500  can then be used to dilate and/or retract the tissue without requiring it to be replaced with another instrument. 
         [0052]    In another embodiment, the surgeon may place their finger inside the retractor  500  in a non-inflated state, and use his or her finger, now encased in the retractor, to probe and dissect the tissue. When the surgeon removes their finger the retractor will remain in place and can be inflated to retract the tissue without being replaced by an additional instrument. 
         [0053]      FIG. 6  is a flow diagram  600  for one exemplary method of providing access to a surgical site in a patient using an inflatable retractor. First, an incision is made at the surgical site  610 . The incision site may then be prepared for the insertion of the inflatable retractor  620 . The inflatable retractor can then be inserted into the incision site  630 . Once inserted, the inflatable retractor can then be inflated to retract tissue from the surgical site  640 . 
         [0054]    In one embodiment, the step of preparing the incision (step  620 ) involves additional steps. For example, blunt finger dissection between muscle planes may be performed using the actual finger of the surgeon or the inflatable retractor  500  of  FIG. 5 . Continuous or serial dilation with or without a guide-wire may be performed to expand the incision opening for insertion of a guide or retractor. Alternately, the inflatable retractor itself may be used for dilation. 
         [0055]    Once dilation is completed, then a guide can be inserted into the incision. The guide can be used to sweep back muscle and tissue from the surgical site to find a target for inserting the inflatable retractor. An example of suitable guide can be seen in  FIG. 7A . Here the guide  700  features a hollow insertion cannula  710  for guiding the insertion and removal of surgical instruments, including the inflatable retractor, and a handle  720  attached to the proximal end of the cannula  710  for inserting and positioning the insertion cannula  710  in the incision site. Once a target for placing the inflatable retractor is located a drill  740  or awl may be used to create an anchor hole for attaching the anchor attached to the inflatable body. Examples of suitable targets include portions of a vertebra, such as a pedicle, lamina, vertebral body, spinous process, transverse process, or the like. In certain embodiments intermediate anchors such as pedicle screws can be used for attaching the inflatable body. 
         [0056]    Referring again to  FIG. 6 , the step of inserting the inflatable retractor (step  630 ) may also involve multiple steps. In one example, these steps include attaching an anchor on a distal end of the inflatable retractor to a bone in the surgical site through the incision. In some embodiments this involves using the guide shown in  FIG. 7 . In such an example, the guide, such as a hollow insertion cannula, is inserted in the incision. An anchor of the retractor is passed through the hollow insertion cannula such that the body of the retractor in a deflated state extends through an opening in the hollow insertion cannula. The anchor of the retractor is then attached to the target. The hollow insertion cannula may then be withdrawn so that the deflated or semi-inflated retractor extends through the incision. In some embodiments an insertion tool  750  as shown in  FIG. 7B  is used. The inserter tool  750  is used to pass the anchor of the inflatable retractor though the insertion cannula and attach the anchor to the target. 
         [0057]    The inflatable retractor is preferably inserted into the incision in a deflated state. In some embodiments, the deflated retractor is inserted using an instrument such as a dilator, catheter, trochar, or sleeve. In the case of a dilator, the deflated retractor may be wrapped around the dilator which is inserted into the incision. When the dilator is withdrawn from the incision the retractor unwraps from the dilator and is left behind in the incision. In another embodiment, the deflated or semi-inflated retractor may be inserted along a guide-wire. In still other embodiments, the deflated or semi-inflated retractor may be inserted and positioned by using a finger of the surgeon as discussed above. Alternately, a catheter, trochar, or sleeve can be used to contain, insert, and deploy the retractor in a deflated state. In some embodiments, additional instruments, such as forceps, may be used to position and deploy the inflatable retractor in situ. In some such embodiments, the positioning of the retractor in situ is performed with the aid of radiopaque markers that are discernable when viewed on a fluoroscope. 
         [0058]    In another embodiment, as depicted in  FIGS. 8A and 8B , the retractor  800  could be inserted by being contained in the sheath  900  of a cannulated screwdriver  910  while attached to a bone screw  920  as seen in  FIG. 8A . Once the bone screw  920  is in place, the sheath  900  can be removed leaving the deflated retractor  800  attached to the screw  920  as seen in  FIG. 8B . The retractor  800  may then be deployed by rotating it into position, as seen in  FIG. 8C , and inflating the retractor  800  as seen in  FIG. 8D . In this particular embodiment, the retractor  800  further includes a support ring  870  to maintain the shape of the inflatable body  810 . The retractor  800  may be attached to the screw by a pin, c-clip, retaining ring, polymer tether, fracture tab or other suitable removable attachment means  930 . 
         [0059]    Once the inflatable retractor has been inserted, it can then be inflated to retract tissue at the surgical site (step  640 ). As discussed above, the inflatable retractor may be inflated with a liquid, gas, or combination of both. 
         [0060]    In some embodiments a hardening agent, such as an epoxy, may be used inflate the retractor. Once the retractor is inflated the epoxy sets-up or hardens to make the retractor rigid. Alternately, a hardening agent, such as a spray epoxy, may be applied to the inner surface of the retractor inflated with gas or liquid to rigidify the retractor. An example of this can be seen in  FIGS. 9A-9D . 
         [0061]    In  FIG. 9A  an insertion device  940  is used to deploy an inflatable body  950  at a surgical site. Once deployed at the surgical site, the inflatable body  950  may be inflated to retract tissue and create a cavity  960  for accessing the surgical site as seen in  FIG. 9B . In this embodiment, the inflatable body  950  is sealed at the distal end  962  of the cavity  960  for deployment and inflation. Once the inflatable body is inflated a hardening agent  970  may be applied to the interior of the cavity  960  such that the sidewalls  952  are coated with the hardening agent  970  as seen in  FIG. 9C . Once the hardening agent  970  has set up such that the sidewalls  952  of the inflatable body  950  defining the cavity  960  are rigid, the distal end  962  of the cavity  950  may be opened to provide access to the surgical site as shown in  FIG. 9D . 
         [0062]    Once sufficient retraction of issue is obtained, necessary surgical procedures may then be performed at the surgical site. After the procedure has been performed at the surgical site, the inflated retractor may be deflated by puncturing the inflated body with an instrument such as a scalpel or releasing the pressure valve, or changing the temperature of the internal media, or by adding a softening agent. If the retractor includes an anchor, the anchor may be disconnected. The deflated retractor may then be removed and the incision closed. As discussed above, the anchor may be made of a reabsorbable or biocompatible material such that the anchors may be left in the body of the patient. 
         [0063]    In some embodiments, such as when the inflatable retractor is used for dilation, an access device such as a rigid port, expandable retractor, or traditional retractor may be inserted over the inflatable retractor to maintain access to a surgical site. An example of this can be seen in  FIGS. 10A-D . Here, as shown in  FIG. 10A , an inflatable body  1010 , in a deflated or semi-inflated state, is inserted over a guide-wire  1020  to a surgical site. Alternately, the inflatable body  1010  may be inserted using any of the techniques discussed herein. Other possible insertion techniques will be apparent to on skilled in the art given the benefit of this disclosure. 
         [0064]    Once the inflatable body  1010  is in position, the inflatable body may be inflated to perform dilation and/or retraction of tissue at the surgical site. An example of this can be seen in  FIG. 10B . In this example the inflatable body  1010  is cylindrical in shape with multiple chambers  1030  formed along the length of the defined cavity  1040 . Other possible configurations will be apparent given the benefit of this disclosure. The inflatable body may be inflated using any of the techniques that have been described above. The guide-wire  1020  may also be removed after inflation. 
         [0065]    Once the inflatable body  1010  is inflated and the incision and tissue dilated and retracted an access device, such as a rigid port  1050  may be inserted over the inflatable body  1010 . An example of this can be seen in  FIG. 10C . In this example, the access device is a port such as ports available in the Pipeline Access System distributed by DePuy Spine (Raynham, Mass.). In other embodiments, the access device may be a retractor such as the Pipeline Expandable Retractor distributed by DePuy Spine (Raynham, Mass.). Other suitable rigid access devices will be apparent to one skilled in the art given the benefit of this disclosure. 
         [0066]    After the access device  1050  is in position, the inflatable body  1010  may then be deflated and removed as discussed above. An example of this can be seen in  FIG. 10D . With the rigid access device  1050  now providing access to the surgical site, any necessary procedures may then be performed through the cavity of the access device  1050 . 
         [0067]    The apparatus and techniques of the present invention provide numerous advantages. The inflatable retractor of the present invention can be used in any approach, including lateral, posterior, and anterior. The inflatable retractor is compact in a deflated state allowing for insertion through a smaller incision and requiring little or no dilation of the incision before insertion. The flexible nature of the inflatable body prevents damage to tissue, vessels, and muscle. The ability to anchor the retractor internally alleviates the need for a bed-mounted arm to secure the retractor. 
         [0068]    The present invention has been described relative to an illustrative embodiment and application in spinal correction surgery. It should be apparent that the present invention may be used in any number of surgical procedures. Since certain changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. 
         [0069]    It is also to be understood that the following claims are to cover all generic and specific features of the invention described herein, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.