Abstract:
A surgical port and dilator is disclosed that are useful for creating access to surgical sites having tortuous geometries and/or requiring relatively long and narrow access to the surgical site. The surgical port or dilator can be provided with an oblique distal end to facilitate placement and the displace tissue near angled surfaces. The surgical port can be inserted into the operative site following dilation in the same fashion as a conventional port. Once inserted, however, the surgical port may then be elongated to provide relatively long and narrow, elliptically-shaped access to the surgical site. The elongation of the port allows the surgeon access to long and narrow surgical sites, such as the spine, without having to expand radially. This reduces trauma to the patient. A locking means is also provided to hold the surgical port in the open position until a release mechanism is activated.

Description:
RELATED APPLICATIONS  
       [0001]     [Not Applicable] 
       FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     [Not Applicable] 
       MICROFICHE/COPYRIGHT REFERENCE  
       [0003]     [Not Applicable] 
       BACKGROUND OF THE INVENTION  
       [0004]     The disclosed inventions relate to surgical ports and associated dilators. In particular, the inventions relate to surgical ports and dilators useful for minimally invasive surgery.  
         [0005]     In the past, surgery typically required large incisions to provide visual and instrument access to the surgical site. These large incisions resulted in significant blood loss, damage to muscle tissue, long healing times accompanied by prolonged pain, and significant scarring. Today, however, many surgeries are conducted using minimally invasive techniques. These techniques minimize patient trauma by creating a relatively small incision, followed by the introduction of dilators to increase the effective size of the incision. Following dilation, surgery is performed through a surgical port inserted into the dilated incision. Instead of cutting through the muscle surrounding the surgical site, dilation effectively splits the muscle. Splitting, rather than cutting the muscle causes less damage to the muscle and leads to faster recovery times and reduced patient discomfort.  
         [0006]     Dilators develop a channel from the subcutaneous layer of a patient to the site of operation. A small incision, paralleling any underlying muscle, is made slightly longer than ½ the circumference of the largest dilator, or if used, port. A solid, pointed rod, variously described as a first dilator or guidewire, is then inserted into the incision to penetrate the underlying structures and reach the surgical site. It is best if the rod can be positioned against a bony surface as application of the dilators will attempt to push this rod forward. X-rays may be taken before and/or after insertion of the rod to confirm placement at the desired surgical site.  
         [0007]     Increasingly larger diameter dilators can then be sequentially placed over each other to enlarge the channel. The larger diameter of the sequential dilators help to dilate the path of exposure while the series of tubes lessens the forces needed to create the path. The pointed tip of the dilators eases insertion and helps to widen the base of the channel when the dilator is orbited around a central axis formed through the center of the dilator along its length at the level of the skin.  
         [0008]     In lieu of dilation, mechanical retractors can be used. Mechanical surgical retractors are hand-held or table-mounted metal retractor blades that are inserted into the incision, and thereafter retracted and held or locked in place to increase the effective opening of the incision. A drawback of using retractors is that, in comparison to dilators, a relatively large incision must be made to provide for placement of the retractor blades. Dilators and surgical ports, on the other hand, typically gain access to the surgical site by making a smaller incision, inserting a small probe into the incision, and then creating a progressively larger circular opening by repeatedly sliding larger dilators over the probe, thereby splitting the muscle. This splitting of the muscle is less traumatic and therefore offers a quicker post surgery recovery.  
         [0009]     Conventional dilators and surgical ports, however, are not suitable for all surgical applications. For example, conventional dilators are unable to completely dilate muscle away from the lamina of the spine due to the tortuous geometry of the lamina. Thus, muscle located between the dilator and the lamina must typically be cut away to access the lamina when using conventional dilators.  
         [0010]     Due to the geometry of the spine, many spinal surgical procedures require a long, narrow opening. Thus, another drawback of dilators is that a circular opening is not practical for most spinal surgeries because of the limited access it offers to the spine given the size of the dilated opening. The use of dilators and surgical ports are therefore generally limited to procedures involving very precise access to the spine, such as for single level discectomy.  
         [0011]     Mechanical retractors, on the other hand, offer the promise of a long, narrow opening. As discussed above, however, mechanical retractors require a relatively large initial incision that involves cutting, rather than splitting of muscle.  
         [0012]     Hence, there is a long-felt need for a device and method for enlarging minimally invasive incision by dilation, regardless of the orientation of the surgical access in relation to the surgical site. There is also a long-felt need for a device and method for enlarging minimally invasive incision by dilation that can displace muscle away from surgical sites possessing a tortuous geometry. Furthermore, there is also a long-felt need for a device and method for enlarging the dilated incision to create a long and narrow access to the surgical site by splitting, rather than cutting muscle surrounding the surgical site.  
       BRIEF SUMMARY OF THE INVENTION  
       [0013]     A novel surgical port and dilator is provided for surgeons requiring a minimally invasive access to a surgical site. The present surgical port and dilator are particularly advantageous because the surgical port and/or the dilator can be configured with an oblique distal end. This oblique distal end is advantageous in surgeries where the surgical site is not level to the plane of the patient, e.g. spinal surgeries. Furthermore, various configurations of the oblique distal end of the surgical port and/or dilator facilitates the displacement of muscle from areas having tortuous geometries, such as the spinal lamina. In addition, the present surgical port can create a relatively long and narrow access to the surgical site by splitting the muscle surrounding the surgical site, rather than cutting it. The distal end of the surgical port can also be angled to accommodate the position of the surgical site in relation to the plane of the surgical access to the patient.  
         [0014]     The present surgical dilators are inserted into a minimally invasive incision in the same fashion as a conventional dilator. Once inserted, however, the oblique distal end of the dilator can conform to a surgical site that is not aligned with the plane of the patient. Moreover, the dilator can be manipulated to maneuver along angled surfaces. In this case, the outer dilator can be replaced by one that is tapered on one or both sides. The tip of this taper can be placed against the highest portion of the base and then rotated, while keeping contact with bone, to the lowest point. In the spine, the tip begins at the base of the spinous process, rotates along the lamina, and comes to rest near the facet joint.  
         [0015]     The outer dilator diameter is just under the inner diameter of the surgical port, and a surgical port with an oblique distal end can therefore be placed over the dilator, and the same motion repeated. This further clears muscle off of the bony base and helps move it to the periphery of the surgical port. With downward pressure on the surgical port, the dilators can be removed and the holding fixture can be applied.  
         [0016]     The surgical port can also enlarge access to the surgical site, either in conjunction with dilators or by itself. The access created by the dilators is substantially circular, while the access created by the surgical port is relatively long and narrow. The elongation of the port allows the surgeon access surgical sites, such as the spine, where an expansion in diameter is not needed and may result in unnecessary trauma to the patient. A locking means is also provided to hold the surgical port in the open position until a release mechanism is activated. 
     
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS  
       [0017]     A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:  
         [0018]      FIG. 1  is a side view of an exemplary extendable surgical port shown in an open position near a patient&#39;s spine;  
         [0019]      FIG. 2  is a side view of an exemplary extendable surgical port shown in the closed position;  
         [0020]      FIG. 3  is a top view of the closed surgical port of  FIG. 2 ;  
         [0021]      FIG. 4  is a side view of an exemplary extendable surgical port shown in an open position;  
         [0022]      FIG. 5  is a top view of the open surgical port of  FIG. 4 ;  
         [0023]      FIG. 6  is a cut-away side view of a locking mechanism, shown in the locked position for holding the surgical port in position;  
         [0024]      FIG. 7  is a cut-away side view of a locking mechanism, shown in the unlocked position for extending or closing the surgical port;  
         [0025]      FIG. 8  is an exploded view of an exemplary extendable surgical port;  
         [0026]      FIG. 9  is a side view of an exemplary extendable surgical port with an oblique distal end, shown in the closed position;  
         [0027]      FIG. 10  is a side view of an exemplary non-extendable surgical port with an oblique distal end;  
         [0028]      FIG. 11  is a top view of the non-extendable surgical port of  FIG. 10 ;  
         [0029]      FIG. 12  is a first partial side view of the body of an exemplary dilator having an oblique distal end;  
         [0030]      FIG. 13  is a second partial side view of the body of the exemplary dilator shown in  FIG. 12  rotated ninety degrees from the position shown in  FIG. 12 ;  
         [0031]      FIG. 14  is top view of the distal end of the body of the exemplary dilator shown in  FIG. 13 ;  
         [0032]      FIG. 15  is a first partial side view of the body of an exemplary dilator depicting a first configuration of an asymmetrical oblique distal end;  
         [0033]      FIG. 16  is a second partial side view of the body of the exemplary dilator shown in  FIG. 15  rotated ninety degrees from the position shown in  FIG. 15 ;  
         [0034]      FIG. 17  is top view of the distal end of the body of the exemplary dilator shown in  FIG. 16 ;  
         [0035]      FIG. 18  is a first partial side view of the body of an exemplary dilator depicting a second configuration of an asymmetrical oblique distal end;  
         [0036]      FIG. 19  is a second partial side view of the body of the exemplary dilator shown in  FIG. 18  rotated ninety degrees from the position shown in  FIG. 18 ;  
         [0037]      FIG. 20  is top view of the distal end of the body of the exemplary dilator shown in  FIG. 19 ;  
         [0038]      FIG. 21  is a first partial side view of the body of an exemplary dilator depicting a third configuration of an asymmetrical oblique distal end;  
         [0039]      FIG. 22  is a second partial side view of the body of the exemplary dilator shown in  FIG. 21  rotated ninety degrees from the position shown in  FIG. 21 ;  
         [0040]      FIG. 23  is top view of the distal end of the body of the exemplary dilator shown in  FIG. 22 ;  
         [0041]      FIG. 24  depicts a cross section of a patient&#39;s spine;  
         [0042]      FIG. 25  depicts a cross section of conventional dilator inserted near a patient&#39;s spine;  
         [0043]      FIG. 26  depicts a cross section of a dilator having an oblique distal end following initial insertion near a patient&#39;s spine;  
         [0044]      FIG. 27  depicts the dilator of  FIG. 26  following manipulation of the dilator to displace muscle away from the spine; 
     
    
       [0045]     Repeat use of reference characters throughout the present specification and appended drawings is intended to represent same or analogous features or elements of the invention.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0046]     Reference now will be made in detail to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on or with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations. Other objects, features and aspects of the present invention are disclosed in or are apparent from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.  
         [0047]     To achieve increased access to the spinal area  58  for surgery, surgical port  50  can be elongated as shown in  FIG. 1  to provide the desired relatively long and narrow access to spinal area  58 . Prior to extension, however, closed surgical port  50  (see  FIGS. 2 and 3 ) is first inserted into an incision over the surgical site, in this case spinal cord  58 . Distal ends  14  of body segments  10  and  12  are positioned near surgical site  58 . Once in place, immobilizer arm  60  can be attached to frame  54  using an adaptor  26 . Immobilizer arm  60  is also attached to a stabilizing structure, such as the operating table (not shown), to steady surgical port  50 .  
         [0048]     Insertion of surgical port  50  in the closed position permits the surgeon to use a relatively small incision, and perhaps minimal dilation, thereby avoiding the large-scale cutting of muscle associated with increased access to spinal  58  provided by larger incisions. The desired increased access to spinal area  58  is instead created by elongating surgical port  50 , thereby splitting and stretching the muscle, which minimizes cutting of the muscle.  
         [0049]     Elongation of surgical port  50  is generally accomplished by sliding second body segment  12  away from first body segment  10  along frame arm  30 . The resulting access to spinal area  58  is generally elliptical in shape due to the linear separation of generally semicircular body segments  10  and  12  (see  FIG. 5 ). Surgery can then be performed through the long and narrow opening provided by elongated surgical port  50 . In addition, a locking mechanism  62 , depicted and discussed further in reference to  FIGS. 2-8 , can be employed to lock surgical port  50  in the desired elongated or closed position.  
         [0050]     Following surgery on the surgical site  58 , surgical port  50  can be closed, disconnected from immobilizer arm  60 , and removed from the incision. The body will then close around and over the surgical site, and patient recovery times and pain levels during healing will be decreased.  
         [0051]     Referring now to  FIGS. 2 and 3 , this particular embodiment of surgical port  50  includes a frame  54  comprised of a first frame section  16  and a second frame section  18 . Surgical port  50  also includes a body  52  comprising a first body segment  10  and a second body segment  12 . Body segments  10  and  12  each have a distal end  14 , and a proximal end  15 . The proximal end  15  of first body segment  10  is attached to first frame section  16 , and the proximal end  15  of second body segment  12  is attached to second frame section  18 . Frame arms  30  are attached to first frame section  16 , and extend through second frame section  18 . An adaptor  26  is attached to first frame section  16  to facilitate the connection of the surgical port  50  to an operating table (not shown) or other stabilizing structure using one or more immobilizer arms  60  (see  FIG. 1 ). An adaptor fastener  28  is used to attach adaptor  26  to first frame section  16 . A locking mechanism, comprising a locking bar  20 , in conjunction with second frame section  18 , locking spring  22 , and frame arms  30 , serves to prevent the movement of first body segment  10  relative to second body segment  12 , thereby holding surgical port  50  in an extended or closed position as required during the surgery. The locking mechanism is discussed further in reference to  FIGS. 6 and 7 .  
         [0052]      FIGS. 4 and 5  depict surgical port  50  in an extended position. Relative to  FIGS. 2 and 3 , respectively, the second frame section  18  and attached second body segment  12  have moved away from the corresponding first frame section  16  and attached first body segment  10  along frame arms  30 . Locking bar  20  is in the locked position. Notice the elongated, elliptical configuration of the resulting opening between first body segment  10  and second body segment  12  seen in  FIG. 5 .  
         [0053]     It should be understood that while frame sections  16  and  18  and body segments  10  and  12  are depicted as separate pieces, an extendable surgical port having a unitary frame with frame sections and a unitary body with body segments is also contemplated. For example, frame sections  16  and  18  and body segments  10  and  12  could be joined by a flexible material (not shown) without departing from the scope of the extendable surgical port. Likewise, it should also be understood that although  FIGS. 2 through 5  depict two frame arms  30 , other configurations, such as a single frame arm (not shown) are also contemplated within the scope of the extendable surgical port. Other changes and variations may be made by those of ordinary skill in the art without departing from the spirit or the scope of the extendable surgical ports set forth in the claims.  
         [0054]      FIGS. 6 and 7  show the locking mechanism of surgical port  50  in the locked and unlocked positions, respectively. Referring to  FIG. 6 , the locking mechanism is in its normally locked position. Spring  22  has forced locking bar  20  to pivot in pivot point  24  in second frame section  18 . Hole  34  in locking bar  20  (best seen in  FIG. 7 ) is configured such that locking bar  20  engages frame arm  30  at contact points  32  somewhere along frame arm  30 , depending on the position of second frame section  18 , when spring  22  biases locking bar  20  away from second frame section  18 .  
         [0055]      FIG. 7  shows the locking mechanism in the unlocked position after force  36  is applied as shown. Force  36 , easily applied by hand, overcomes the force applied by spring  22 , pivoting locking bar  20  towards second frame section  18  and releasing the engagement of locking bar  20  with frame arm  30 . Once second frame section  18  and attached second body segment  12  have reached a desired position relative to first frame section  16  and attached first body segment  10 , the surgical port can be relocked by simply releasing force  36 .  
         [0056]      FIG. 8  depicts an exploded view of a presently preferred embodiment of surgical port  50 . Note hole  34  in locking bar  20 . The relationship of the assembled components is best visualized in this view. Frame arms  30  fit through holes  38  in second frame section  18 . One frame arm  30  also fits through hole  34  in locking bar  20 . Locking bar  20  pivots in pivot point  24  in second frame section  18 , while spring  22  is partially recessed in recess  40  in second frame section  18 . It is to be understood that although this presently preferred embodiment depicts screws as the attaching means for many parts of surgical port  50 , such means of attachment are not limited to screws and instead encompass all methods of attachment known to those skilled in the art.  
         [0057]     Since the anatomy of the spine is rarely level to the plane of the patient, it is often desirable to provide distal end  14  of surgical port body  52  with an oblique, or angled surface.  FIG. 9  depicts another embodiment of surgical port  50  in the closed position. In this embodiment, the distal ends  14  of first body segment  10  and second body segment  12  are symmetrically oblique. In other words, the angled surfaces of respective body segments  10  and  12  match up. Surgical port  50  embodying this feature can be selected to closely match the angle of the spine relative to the plane of the patient, resulting in surgical access close to the surgical site without impacting the spine.  
         [0058]      FIGS. 10 and 11  depict yet another embodiment of surgical port  50 . This embodiment is not extendable, and therefore body  52  does not include separate body segments  10  and  12 . Similarly, frame  54  does not include frame sections  16  and  18 . The distal end  14  of body  52 , however, is still symmetrically oblique.  
         [0059]      FIGS. 12 through 20  depict dilators  80  wherein opposing angles  84  of distal end  82  are asymmetrically oblique. The unique opposing, mismatched angled surfaces  84  of distal end  82  of dilator  80  allows for uneven splitting of muscle closest to the vertebral body or lamina. This configuration provides for customized access to the surgical site along the contours of an irregular surface, such as the spine. In  FIGS. 12, 13 ,  16 , and  19 , the opposing angles  84  of distal end  82  and/or central opening  86  of dilator  80  are depicted using dotted lines. Top views of distal end  82  in  FIGS. 14, 17 , and  20  emphasize the difference between opposing angles depicted in  FIGS. 13, 16 , and  19  respectively.  
         [0060]      FIG. 12  depicts dilator  80  having a central opening  86  in a body  88  and a symmetrically oblique distal end  82 . Angled surface  84  is merely representative of a symmetrically oblique configuration and should be considered only one embodiment of this aspect of the present dilator. Depending on the particular situation, a multitude of other angles could be used to provide angled surface  84 .  FIG. 13  represents dilator  80  of  FIG. 12  rotated ninety degrees to further illustrate angled surface  84 .  FIG. 14  is a top view of dilator  80  of  FIG. 13 .  
         [0061]      FIG. 15  depicts dilator  80  having a central opening  86  in a body  88  and an asymmetrically oblique distal end  82 . Opposing angled surfaces  84  are merely representative of an asymmetrically oblique configuration and should be considered only one embodiment of this aspect of the present dilator  80 . Depending on the particular situation, a multitude of other angles could be to provide angled surfaces  84 , including, but not limited to the configurations shown in  FIGS. 18-23 .  FIG. 16  represents dilator  80  of  FIG. 15  rotated ninety degrees to further illustrate angled surfaces  84 .  FIG. 17  is a top view of dilator  80  of  FIG. 16 .  
         [0062]      FIG. 18  depicts dilator  80  having a central opening  86  in a body  88  and an asymmetrically oblique distal end  82 . Opposing angled surfaces  84  are merely representative of an asymmetrically oblique configuration and should be considered only one embodiment of this aspect of the present dilator. Depending on the particular situation, a multitude of other angles could be used to provide angled surfaces  84 , including, but not limited to those configurations shown in  FIGS. 15-17  and  FIGS. 21-23 .  FIG. 19  represents dilator  80  of  FIG. 15  rotated ninety degrees to further illustrate angled surfaces  84 .  FIG. 20  is a top view of dilator  80  of  FIG. 16 .  
         [0063]      FIG. 21  depicts dilator  80  having a central opening  86  in a body  88  and an asymmetrically oblique distal end  82 . Opposing angled surfaces  84  are merely representative of an asymmetrically oblique configuration and should be considered only one embodiment of this aspect of the present dilator. Depending on the particular situation, a multitude of other angles could be used to provide angled surfaces  84 , including, but not limited to the configurations shown in  FIGS. 15-20 .  FIG. 22  represents dilator  80  of  FIG. 15  rotated ninety degrees to further illustrate angled surfaces  84 .  FIG. 23  is a top view of dilator  80  of  FIG. 16 .  
         [0064]      FIGS. 24 through 27  depict dilator  80  in use near the spine  66 . As shown in  FIG. 24 , the spine  66  includes muscles  64 , lamina  68  (bone covering the spinal cord), and discs  70 . Notice that lamina  68  creates obtuse angle  72  between the tip of the spinous process  65  and the facet joint  67 . The area around obtuse angle  72  is surrounded by muscles  64 . Conventional dilators  90  (see  FIG. 25 ), are unable to remove sufficient muscle  64  from lamina  68 , and therefore it is frequently necessary to cut portions of muscle  64  to provide surgical access to lamina  68 .  
         [0065]     To illustrate this problem,  FIG. 25  represents a conventional dilator  90  inserted along lamina  68 . The distal end  92  of conventional dilator  90  lacks the oblique configuration of the distal end  14  of present dilator  80 . If conventional dilator  90  is manipulated near lamina  68 , muscle  64  below distal end  92  of conventional dilator  90  in region  74  would continue to obstruct access to lamina  68  below the base of the spinous process  69 . Thus, muscle  64  in region  74  would have to be cut away from lamina  68 .  
         [0066]     In  FIG. 26 , however, present dilator  80  is provided with an oblique distal end  82  which is inserted until adjacent to lamina  68 . Angled surface  84  of dilator  80  can then be maneuvered along lamina  68  by rotating and further inserting dilator  80  until muscle  64  in region  74  is maneuvered away from lamina  68  as seen in  FIG. 27 . Thus, access to the surgical site can be created without excessive cutting of muscle  64  in region  74 .  
         [0067]     Following dilation, an oblique surgical port  55  (depicted in  FIGS. 9-11 ) may be inserted over present dilator  80 . Angled surface  56  of oblique surgical port  55  can be maneuvered along lamina  68  by rotating and further inserting oblique surgical port  55  until muscle  64  in region  74  is maneuvered away from lamina  68  in the same manner previously discussed with respect to dilation and  FIG. 27 . Alternatively, oblique surgical port  55  may be used after conventional dilation to maneuver muscle  64  in region  74  away from lamina  68 .  
         [0068]     Although preferred embodiments of the invention have been described using specific terms, devices, and methods, such description is for illustrative purposes only. The words used are words of description rather than of limitation. It is to be understood that changes and variations may be made by those of ordinary skill in the art without departing from the spirit or the scope of the present surgical port, which is set forth in the following claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained therein.