Laterally expanding surgical dilator

BACKGROUND

p-0002The present invention relates generally to percutaneous surgeries and more particularly, to devices for performing percutaneous, minimally invasive spinal surgeries.

p-0003Traditional surgical procedures for pathologies located deep within the body can cause significant trauma to the intervening tissues. These open procedures often require a long incision, extensive muscle stripping, prolonged retraction of tissues, denervation and devascularization of tissue. Most of these surgeries require a recovery room time of several hours and several weeks of post-operative recovery time due to the use of general anesthesia and the destruction of tissue during the surgical procedure. In some cases, these invasive procedures lead to permanent scarring and pain that can be more severe than the pain leading to the surgical intervention.

p-0004Minimally invasive alternatives such as arthroscopic techniques reduce pain, post-operative recovery time and the destruction of healthy tissue. Orthopedic surgical patients have particularly benefited from minimally invasive surgical techniques. The site of pathology is accessed through portals rather than through a significant incision thus preserving the integrity of the intervening tissues. In some instances, these minimally invasive techniques require only local anesthesia. The avoidance of general anesthesia reduces post-operative recovery time and the risk of complications.

p-0005Minimally invasive surgical techniques are particularly desirable for spinal and neurosurgical applications because of the need for access to locations deep within the body and the danger of damage to vital intervening tissues. For example, a common open procedure for disc herniation, laminectomy followed by discectomy requires stripping or dissection of the major muscles of the back to expose the spine. In a posterior approach, tissue including spinal nerves and blood vessels around the dural sac, ligaments and muscle must be retracted to clear a channel from the skin to the disc. These procedures normally take at least one-two hours to perform under general anesthesia and require post-operative recovery periods of at least several weeks. In addition to the long recovery time, the destruction of tissue is a major disadvantage of open spinal procedures. This aspect of open procedures is even more invasive when the discectomy is accompanied by fusion of the adjacent vertebrae. Many patients are reluctant to seek surgery as a solution to pain caused by herniated discs and other spinal conditions because of the severe pain sometimes associated with the muscle dissection.

p-0006In order to reduce the post-operative recovery time and pain associated with spinal and other procedures, micro-surgical techniques have been developed. The objective of any minimally invasive procedure is to accomplish the same clinical objectives as the traditional, open surgery while minimizing soft tissue retraction. Existing sequential dilation processes consist of inserting multiple increasing diameter dilators until the correct diameter is achieved. A tubular retractor is then placed over the dilators and the dilators are then removed. The retractor is left in place with the surrounding muscle and tissue having been dilated out of the working space.

p-0007For some applications, it would be beneficial to be able to dilate an incision quickly without the use of multiple individual dilators. As such, a need exists for a device that will allow physicians to quickly dilate an incision without the use of multiple individual components.

SUMMARY

p-0008According to one aspect a surgical dilator is disclosed that is capable of dilating an incision in a patient. The surgical dilator includes a main body having a distal end and a proximal end. A locking cap is connected with the proximal end of the main body that is operable to lock the surgical dilator in a closed state for insertion into an incision as well as to unlock the surgical dilator to an open state after being inserted into the incision. A plurality of blades having a second proximal end pivotally connected with the distal end of the main body and extend downwardly toward a second distal end. When the surgical dilator is in the closed state the blades taper downwardly and inwardly from the second proximal end toward the second distal end to form an insertion tip and when the surgical dilator is in the open state the blades are operable to laterally expand.

p-0009An expansion tube is sized to be inserted into an interior cavity defined by the main body and make contact with an interior surface of each of the blades. As the expansion tube is compressed into the interior cavity the expansion tube causes the blades to laterally expand and dilate the incision. A width of each of the blades is larger at the proximal end and tapers to a smaller width at the second distal end. In the closed state the blades form a generally uniform cone-shaped blade. A collar is positioned between the proximal end of the main body and an end of the locking cap. A plurality of locking pins is connected with a lower surface of the collar and extends downwardly through a plurality of channels formed in the main body. In the closed state a distal end of each the locking pins extend outwardly from the distal end of the main body and engage an aperture in a respective blade thereby forcing the blades into the closed state. In the open state a distal end of each the locking pins is retracted away from the blades thereby allowing the blades to pivotally move in relation to the main body.

p-0010Another aspect discloses a surgical dilator that is capable of dilating an incision in a patient. In this form, the surgical dilator includes a main body having a distal end and a proximal end. A locking cap is connected with the proximal end of the main body. A collar is positioned between the locking cap and the proximal end of the main body. A plurality of locking pins are connected with an end of the collar and positioned in a plurality of channels located in the main body. A distal end of the locking pins is operable to protrude outwardly from the channels on the distal end of the main body. A plurality of blades is movably connected with the distal end of the main body. The distal ends of the locking pins are operable to engage an aperture in the blades to force the blades into a closed state for inserting the blades into an incision.

p-0011In one form, the second distal ends of the locking pins are operable to be released from the blades so that the blades are operable to laterally expand. A plurality of springs are included that have a first portion positioned in a set of apertures located on the proximal end of the main body and a second portion in engagement with the end of the collar. The springs are operable to force the locking cap upwardly thereby causing the distal ends of the locking pins to disengage the aperture in the blades thereby releasing the blades from the closed state. A pin is positioned in a proximal portion of the main body that extrudes through a control slot in a side surface of the locking cap. As the locking cap is rotated about the main body the control slot includes a vertical slot portion that becomes aligned with the pin thereby causing the springs to force the locking cap upwardly thereby disengaging the locking pins from the aperture.

p-0012In another form, the locking cap includes a conductive area and at least a lower portion of at least one of the blades includes a second conductive area. The second conductive area is configured to transmit an electric signal to provide the surgical dilator with neural monitoring capabilities. The distal end of the main body includes a plurality of mounting arms and a proximal end of each of the blades includes an arm. The arms of the blades are oriented between the mounting arms of the main body and the arms are pivotally connected to the mounting arms with a plurality of pins. The pins are inserted into the mounting arms and into the arms of the blades through a plurality of pin channels located on a side surface of the mounting arms. The surgical dilator also includes an expansion tube that is sized to be inserted into an interior cavity formed in the main body and into contact with an interior surface of the blades. As the expansion tube is compressed downwardly the blades laterally expand when the blades are not in the closed state.

p-0013Yet a further aspect discloses a surgical dilator that is capable of dilating an incision in a patient. The surgical dilator includes a main body having a distal end and a proximal end. A plurality of blades is connected with and extend downwardly from the distal end of the main body. The surgical dilator includes means for orienting the blades in a locked state in which the blades combine to form a generally uniform blade structure having a generally cone-shaped configuration. In addition, the surgical dilator further includes means for orienting the blades in an unlocked state in which the blades can be laterally expanded.

p-0014In one representative form, the means for orienting the blades in the locked state comprises a locking cap connected with the proximal end of the main body, a collar positioned between the proximal end and the locking cap having a plurality of locking pins connected therewith that extend through a plurality of channels in the main body to engage the blades to orient the blades in the locked state. In addition, the means for orienting the blades in the unlocked state comprises a control slot on a side surface of the locking cap and a pin extending through the control slot that is located on the main body. When the pin is oriented in the control slot in a predetermined position the locking pins disengage the blades thereby allowing the blades to laterally expand. A plurality of springs is positioned between the proximal end of the main body and the collar to bias the locking pins in a position in which the blades are maintained in the unlocked state.

p-0015Related features, aspects, embodiments, objects and advantages of the present invention will be apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0016<figref idrefs="DRAWINGS">FIG. 1</figref> is a perspective view of a surgical dilator oriented in a closed or retracted state.

p-0017<figref idrefs="DRAWINGS">FIG. 2</figref> is a perspective view of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref> oriented in an open or expanded state.

p-0018<figref idrefs="DRAWINGS">FIG. 3</figref> is a perspective view of a portion of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0019<figref idrefs="DRAWINGS">FIG. 4</figref> is an end view of a main body of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0020<figref idrefs="DRAWINGS">FIG. 5</figref> is a perspective view of a representative blade of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0021<figref idrefs="DRAWINGS">FIG. 6</figref> is a perspective view of a portion of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0022<figref idrefs="DRAWINGS">FIG. 7</figref> is a perspective view of a portion of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0023<figref idrefs="DRAWINGS">FIG. 8</figref> is a perspective view of a portion of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0024<figref idrefs="DRAWINGS">FIG. 9</figref> is a top view of the surgical dilator illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0025<figref idrefs="DRAWINGS">FIGS. 10</figref><i>a</i>-<b>10</b><i>d </i>is a perspective view of illustrative expansion tubes.

p-0026<figref idrefs="DRAWINGS">FIG. 11</figref> is a perspective view of another representative surgical dilator.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

p-0027For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any such alterations and further modifications in the illustrated devices, and such further applications of the principles of the invention as illustrated herein are contemplated as would normally occur to one skilled in the art to which the invention relates.

p-0028Referring collectively to <figref idrefs="DRAWINGS">FIGS. 1 and 2</figref>, a soft tissue surgical dilator <b>10</b> is disclosed that is operable to dilate an incision <b>12</b> in a patient. As illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>, prior to insertion into the incision <b>12</b> to be dilated, the dilator <b>10</b> is oriented in a closed or retracted state. As set forth in greater detail below, the dilator <b>10</b> is biased in the closed state but can be unlocked to allow the dilator <b>10</b> to laterally expand. After being oriented in the incision <b>12</b> at a predetermined depth, the surgical dilator <b>10</b> is unlocked and then expansion tubes can be inserted into the interior of the dilator <b>10</b> to laterally expand a plurality of tapered blades <b>14</b> attached to a distal portion <b>16</b> of the dilator <b>10</b>. In the closed state, the tapered blades <b>14</b> form a generally uniform cone-shaped dilator blade that includes a small insertion tip or vertex <b>20</b> that expands upwardly and outwardly to a base <b>22</b>. In the illustrated form, while in the closed state the blades <b>14</b> form a generally uniform blade having a generally circular shaped cross-section along the horizontal plane of the blades <b>14</b>. However, other forms are envisioned, for example the blades <b>14</b> could combine in the closed state to form an elliptical or oval shaped unitary insertion blade that laterally expands.

p-0029The dilator <b>10</b> includes a main body <b>18</b>, a locking cap <b>24</b>, and tapered blades <b>14</b>. The locking cap <b>24</b> is used to lock the blades <b>14</b> in the closed state for insertion into the incision <b>12</b> and to release or unlock the blades <b>14</b> so that they can be expanded outwardly for the purpose of dilating the incision <b>12</b>. Referring to <figref idrefs="DRAWINGS">FIG. 3</figref>, the blades <b>14</b> have been removed from a distal end <b>26</b> of the main body <b>18</b>. A plurality of locking members or rods <b>30</b> extend outwardly from a plurality of channels <b>32</b> defined through the main body <b>18</b> while the blades <b>14</b> are oriented in the closed state. As set forth in greater detail below, the locking rods <b>30</b> are retracted in the channels <b>32</b> when the blades <b>14</b> are oriented in the released state for the purpose of dilating the incision <b>12</b>.

p-0030A plurality of blade mounting arms <b>34</b> extend outwardly from the distal end <b>26</b> of the main body <b>18</b>. As illustrated in <figref idrefs="DRAWINGS">FIGS. 3 and 4</figref>, the blade mounting arms <b>34</b> include a plurality of blade mounting pins <b>36</b> that are used to pivotally connect the blades <b>14</b> to the main body <b>18</b>. The blade mounting pins <b>36</b> are inserted into the blade mounting arms <b>34</b> through a plurality of pin channels <b>39</b> that are bored or formed in the blade mounting arms <b>34</b>. Referring to <figref idrefs="DRAWINGS">FIG. 5</figref>, each blade <b>14</b> includes a channel <b>38</b> in an arm <b>40</b> extending from a proximal end <b>42</b> of the blade <b>14</b>. A portion of the mounting pins <b>36</b> that extend out of the blade mounting arms <b>34</b> are positioned in the channel <b>38</b> when the blades <b>14</b> are connected with the main body <b>18</b>. As illustrated in <figref idrefs="DRAWINGS">FIG. 5</figref>, the blades <b>14</b> include a blade body <b>44</b> that extends from the proximal end <b>42</b> of the blade <b>14</b> to a distal end <b>46</b>. The blade body <b>44</b> has a greater width at the proximal end <b>42</b> and tapers downwardly to a smaller width at the distal end <b>46</b>. The blade body <b>44</b> and arms <b>40</b> have a generally curved cross-sectional shape along a horizontal plane. In the form having four blades <b>14</b>, the generally curved cross-sectional shape comprises 90 degrees of a circle when viewed along the horizontal plane. Although four blades <b>14</b> are used in the illustrated form, it is envisioned that at least two or more blades <b>14</b> can be used in other forms.

p-0031Referring collectively to <figref idrefs="DRAWINGS">FIGS. 1</figref>, <b>3</b> and <b>5</b>, while the blades <b>14</b> are oriented in the closed state, the locking rods <b>30</b> extend outwardly from the distal end <b>26</b> of the main body <b>18</b> and into a closing aperture <b>48</b> in each arm <b>40</b> of each respective blade <b>14</b>. The locking rods <b>30</b> force the blades <b>14</b> to collapse on one another into the closed stated. Referring to <figref idrefs="DRAWINGS">FIGS. 6 and 7</figref>, the locking rods <b>30</b> extend from a distal end <b>50</b> to a proximal end <b>52</b> and have a rod-like shape. In one form, the distal end <b>50</b> of the locking rods <b>30</b> is tapered to facilitate insertion into the closing aperture <b>48</b> in the arm <b>40</b> of each blade <b>14</b>. The proximal end <b>52</b> of the locking rods <b>30</b> includes an external threaded portion <b>54</b>. The surgical dilator <b>10</b> also includes a collar <b>56</b> that has a generally circular cross-sectional shape along a horizontal plane of the collar <b>56</b>. The collar <b>56</b> includes a plurality of internally threaded apertures <b>58</b> that are sized to threadably engage the external threaded portion <b>54</b> of the locking rods <b>30</b>. As such, the locking rods <b>30</b> are connected with the collar <b>56</b> via a threaded connection in this form, but other methods of connecting the locking rods <b>30</b> to the collar <b>56</b> could be used in other forms such as a press or friction fit, a weld, an adhesive or any other suitable connection means.

p-0032As illustrated in <figref idrefs="DRAWINGS">FIG. 7</figref>, the collar <b>56</b> is sized and configured to fit within an interior cavity <b>60</b> defined by the locking cap <b>24</b>. The locking cap <b>24</b> has a generally tubular shape that includes an upper inwardly extending rim <b>62</b> to which an upper surface <b>64</b> of the collar <b>24</b> abuts or is connected with. Referring collectively to <figref idrefs="DRAWINGS">FIGS. 1</figref>, <b>7</b> and <b>8</b>, the interior cavity <b>60</b> of the locking cap <b>24</b> is sized to slide over an outer or exterior surface <b>66</b> of the main body <b>18</b>. In particular, the locking cap <b>24</b> slides over a proximal end portion <b>68</b> of the main body <b>18</b>. Prior to or simultaneously with the attachment of the locking cap <b>24</b> to the main body <b>18</b>, the distal ends <b>50</b> of the locking pins <b>30</b> are aligned with the locking pin channels <b>32</b> and inserted into the locking pin channels <b>32</b> of the main body <b>18</b>.

p-0033A distal end <b>70</b> of the main body <b>18</b> includes a plurality of spring apertures <b>72</b> that are sized and configured to receive a plurality of springs <b>74</b>. When installed, the springs <b>74</b> exert an upward force on a lower surface <b>76</b> of the collar <b>56</b> thereby tending to bias the locking pins <b>30</b> in a retracted state. The locking cap <b>24</b> also includes at least one L-shaped control slot <b>78</b> on an outside surface <b>80</b> of the locking cap <b>24</b> that allows the locking cap <b>24</b> to be oriented in locked and unlocked positions. As previously set forth, in the unlocked position the blades <b>14</b> are free to expand outwardly to dilate the incision <b>12</b> and in the locked position the blades <b>14</b> are forced together in the closed state. Keeping the blades <b>14</b> locked in the closed state permits the blades <b>14</b> to be inserted without having to be concerned about the blades <b>14</b> wanting to separate as the blades <b>14</b> are inserted into the incision <b>12</b>.

p-0034As set forth above, the springs <b>74</b> bias the locking cap <b>24</b> in an upward position by applying force to the lower surface <b>76</b> of the collar <b>56</b>. The L-shaped control slot <b>78</b> comprises a vertical slot portion <b>82</b> and a horizontal slot portion <b>84</b>. The distal end portion <b>68</b> of the main body <b>18</b> includes at least one cap pin aperture <b>86</b> that is sized to receive a locking cap pin <b>88</b> that is exposed on an outside surface <b>90</b> of the main body <b>18</b>. Once the locking pins <b>30</b> are inserted into the main body <b>18</b> and the locking cap <b>24</b> is positioned over the distal end portion <b>68</b> of the main body <b>18</b>, the locking cap pin <b>88</b> is inserted into the cap pin aperture <b>86</b> through the control slot <b>78</b> in the locking cap <b>24</b> thereby securing the locking cap <b>24</b> to the main body <b>18</b>.

p-0035To unlock the blades <b>14</b>, the locking cap <b>24</b> is rotated about the main body <b>18</b> so that the locking cap pin <b>88</b> is exposed to the vertical slot portion <b>82</b> of the control slot <b>78</b>. The springs <b>74</b> then force the collar <b>56</b> and locking cap <b>24</b> upwardly thereby placing the locking pins <b>30</b> in a retracted position in which the locking pins <b>30</b> no longer force the blades <b>14</b> to be in the closed state. In particular, this causes the distal ends <b>50</b> of the locking pins <b>30</b> to be removed from the closing apertures <b>48</b> in the blades <b>14</b> thereby allowing them to pivotally move about the blade mounting pins <b>36</b>. The locking cap pin <b>88</b> makes contact with a distal end <b>92</b> of the vertical slot portion <b>82</b> to stop the locking cap <b>24</b> and collar <b>56</b> from travelling upwardly on the distal end <b>68</b> of the main body <b>18</b> any further than necessary to unlock the locking pins <b>30</b>. To lock the blades <b>14</b> back in a closed state, a user exerts a downward force on the locking cap <b>24</b> thereby causing the springs <b>74</b> to compress and then rotates the locking cap <b>24</b> horizontally to orient the locking cap pin <b>88</b> in the horizontal slot portion <b>84</b> of the control slot <b>78</b>. Compression of the springs <b>74</b> causes the locking cap <b>24</b> to exert a downward force on the collar <b>56</b> thereby forcing the distal ends <b>50</b> of the locking pins <b>30</b> back into the closing apertures <b>48</b> of the blades <b>14</b>. The orientation or alignment of the closing apertures <b>48</b> in the blades <b>14</b> forces the blades <b>14</b> to the closed state as the locking pins <b>30</b> are received in the closing apertures <b>48</b>.

p-0036Referring to <figref idrefs="DRAWINGS">FIGS. 1</figref>, <b>3</b> and <b>9</b>, the main body <b>18</b> has a generally tubular shape defining a hollow interior <b>92</b>. The locking cap <b>24</b> includes a rim <b>62</b> that also defines an opening <b>94</b> into the hollow interior <b>92</b> defined by the main body <b>18</b>. While in the closed state, the blades <b>14</b> define a generally downwardly extending conically shaped uniform blade terminating at a small insertion tip <b>20</b>. In the closed state, interiorly curved surfaces <b>96</b> of the blades <b>14</b> also define a hollow interior portion <b>98</b> of the surgical dilator <b>10</b>. After being inserted into the incision <b>12</b> and placed in the unlocked position, the blades <b>14</b> of the surgical dilator <b>10</b> need to be expanded in order to further dilate the incision <b>12</b>. As set forth in detail below, dilation of the incision <b>12</b> is obtained through the use of tapered tubes that are inserted into the hollow interior <b>92</b> of the main body <b>18</b> and the hollow interior portion <b>98</b> defined by the blades <b>14</b>.

p-0037Referring to <figref idrefs="DRAWINGS">FIGS. 10</figref><i>a</i>-<b>10</b><i>d</i>, a plurality of expansion tubes or members <b>100</b> are illustrated that are configured to laterally expand the blades <b>14</b> so that the incision <b>12</b> can be dilated to a predetermined size. Each expansion tube <b>100</b> includes a distal or insertion end <b>102</b> and a proximal end <b>104</b>. Once the locking cap <b>24</b> is oriented in the unlocked state, the insertion end <b>102</b> of a respective one of the expansion tubes <b>100</b> is inserted through the opening <b>94</b> in the locking cap <b>24</b> and the hollow interior <b>92</b> of the main body <b>18</b> until an outside surface of the expansion tube <b>100</b> makes contact with the interiorly curved surfaces <b>96</b> of the blades <b>14</b>. As illustrated in <figref idrefs="DRAWINGS">FIGS. 10</figref><i>a</i>-<b>10</b><i>d</i>, the insertion ends <b>102</b> of the expansion tubes <b>100</b> have a smaller outside diameter than the proximal ends <b>104</b>. As the outside diameter of the expansion tubes <b>100</b> increases the further the expansion tubes <b>100</b> are inserted or compressed down into the surgical dilator <b>10</b>, the further out the blades <b>14</b> of the surgical dilator <b>10</b> laterally expand.

p-0038In the form illustrated in <figref idrefs="DRAWINGS">FIG. 10</figref><i>a</i>, the expansion tube <b>10</b> is formed having a tapered stepped structure. The expansion tube <b>100</b> includes a plurality of steps <b>110</b> that increase in cross-sectional diameter as they progress from the insertion end <b>102</b> to the proximal end <b>104</b>. As the steps <b>110</b> are inserted further into the surgical dilator <b>10</b>, the steps <b>110</b> continuously make increasing contact with the interiorly curved surfaces <b>96</b> of the blades <b>14</b> thereby causing the blades <b>14</b> to laterally expand outwardly, which in turn causes the incision <b>12</b> to dilate further. In the forms illustrated in <figref idrefs="DRAWINGS">FIGS. 10</figref><i>b</i>-<b>10</b><i>d</i>, the expansion tubes <b>100</b> are tapered outwardly as the body of the expansion tube <b>100</b> travels from the insertion end <b>102</b> to the proximal end <b>104</b>. Again, the further the expansion tubes <b>10</b><i>b</i>-<b>10</b><i>d </i>are inserted into the surgical dilator <b>10</b>, the further the expansion tubes <b>100</b> cause the blades <b>14</b> to laterally expand. As one skilled in the art would recognize, the expansion tubes <b>100</b> illustrated in <figref idrefs="DRAWINGS">FIGS. 10</figref><i>a</i>-<b>10</b><i>d </i>are for illustrative purposes only and various expansion tubes <b>100</b> having different predetermined expansion rates may be utilized herein.

p-0039As the expansion tubes <b>100</b> are inserted and make contact with the internally curved surfaces <b>96</b> of the blades <b>14</b>, the blades <b>14</b> begin to expand laterally. As the blades <b>14</b> expand laterally, gaps <b>120</b> are formed between the respective blades <b>14</b> as illustrated in <figref idrefs="DRAWINGS">FIG. 2</figref>. However, because the expansion tubes <b>100</b> are positioned in contact with the interiorly curved surfaces <b>96</b> of the blades <b>14</b>, the expansion tubes <b>100</b> prevent any tissue from creeping behind the blades <b>14</b>. Any tissue that may attempt to position itself behind the blades <b>14</b> makes contact with the expansion tube <b>100</b>, which prohibits the tissue from orienting itself behind the blades <b>14</b>.

p-0040Referring to <figref idrefs="DRAWINGS">FIG. 11</figref>, in one representative form of the present invention the dilator <b>10</b> is provided with neuromonitoring capabilities. In this form, the dilator <b>10</b> can be substantially formed from a non-conductive material such as, for example, anodized aluminum. In this form, a portion of the locking cap <b>24</b> includes an area <b>120</b> that is conductive and exposed on an outer surface of the locking cap <b>24</b>. The conductive area <b>120</b> permits the attachment of a stimulation signal transfer device <b>122</b> such as, for example, one or more wires to the locking cap <b>24</b>. The stimulation signal transfer device <b>122</b> could be attached by way of a clip <b>124</b> or some other similar attachment device. The stimulation signal transfer device <b>122</b> is connected with an electric stimulation signal generator <b>126</b> that is operable to stimulate the dilator <b>10</b>. The tip portion <b>20</b> of one or more of the blades <b>14</b> also includes a conductive area <b>128</b> exposed on an outer surface of the first dilation member <b>12</b>. Neuromonitoring capability is achieved by stimulating the conductive area <b>128</b> of the tip <b>20</b> with electric signals to aid in detecting the proximity of the tip <b>20</b> to any neural structures. In other forms, the main body <b>18</b> could include the conductive area <b>120</b>.

p-0041In one form, the surgical dilators disclosed herein are sized and configured to achieve a range of dilation from approximately 5.3 mm to 21 mm, but other ranges are envisioned. The dilation members and retaining pins disclosed herein can be manufactured from various materials such as aluminum, anodized aluminum, plastic, titanium, titanium alloys, steel, and so forth.

p-0042Although various embodiments have been described as having particular features and/or combinations of components, other embodiments are possible having a combination of any features and/or components from any of embodiments as discussed above. As used in this specification, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, the term “a member” is intended to mean a single member or a combination of members, “a material” is intended to mean one or more materials, or a combination thereof. Furthermore, the terms “proximal” and “distal” refer to the direction closer to and away from, respectively, an operator (e.g., surgeon, physician, nurse, technician, etc.) who would insert the medical implant and/or instruments into the patient. For example, the portion of a medical instrument first inserted inside the patient's body would be the distal portion, while the opposite portion of the medical device (e.g., the portion of the medical device closest to the operator) would be the proximal portion.

p-0043While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that all changes and modifications that come within the spirit of the invention are desired to be protected.