Abstract:
An endoscopic sheath having a biomimetic retractor for retracting organs and tissues in the body. The inflatable retractor comprises an inflatable balloon configured to retract specific organs and tissues at the site of the endoscopic procedure, with attached inflation and deflation means. In one embodiment, the inflatable retractor is attached to an outer tube or cannula. A second, inner cannula is placed within the outer cannula and attached thereto by a plurality of substantially elastic strands. The strands center the inner cannula while allowing it to be manipulated in any direction.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims benefit of pending provisional U.S. Ser. No. 60/645,923 filed Jan. 21, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to retractors used in surgery, and more specifically, to an inflatable retractor by which an internal organ or other internal body part may be retracted during endoscopic surgery.  
         [0004]     2. Background of the Invention  
         [0005]     The field of endoscopic surgery has been advancing rapidly in recent years. In this form of surgery, procedures are performed inside the body of a patient using instruments inserted through small incisions or ports in the body. The surgery is performed with the aid of an endoscope, which is a thin, tube-like instrument featuring a light source, viewing lenses, and/or various other attachments such as irrigators, scissors, snares, brushes or forceps. Endoscopes may be flexible or rigid, and normally utilize optic fibers to transmit light to the internal cavity. This form of surgery allows internal visualization of the body structure without the necessity of excessive dissection of tissue. Typical endoscopes are in the 5 to 12 mm diameter range and thus require only very small incisions for insertion into the body.  
         [0006]     Endoscopic surgery has developed rapidly because of the numerous benefits arising in favor of the patient. Since there is only a small incision to permit the entrance of the endoscope and other endosurgical devices, endoscopic surgery results in less trauma to the patient&#39;s body and faster patient recovery. For the benefits of endoscopic surgery to arise, however, all aspects of the surgery, such as the initial examination, retraction of internal organs, and the surgical procedure itself, must be capable of being performed through small endoscopic incisions or ports.  
         [0007]     Endoscopic surgery has particular utility in the field of neurosurgery where, for obvious reasons, it is especially desirable to disrupt and/or manipulate as little tissue as possible. Certain tumors, such as those of the Pineal Gland, benefit from such procedures as direct surgery can be curative for benign tumors as well as providing a generous sample for biopsies leading to a definite diagnosis. Direct surgery using traditional stereotactic or endoscopic techniques can result in complications, including EOM dysfunction, altered mental status, hemorrhage, extrapyramidal symptoms, hemiparesis, hemianopsia and seizures. Traditional endoscopic procedures are further complicated due to the use of flexible endoscopes which can be technically difficult to maneuver.  
         [0008]     Therefore, what is needed is a minimally invasive device that would allow surgery to be safely performed on microsurgical anatomy of neurological structures, such as the pineal region of the brain. The ideal device would provide for frameless stereotactic guidance and use a rigid neuroendoscope  
       SUMMARY OF INVENTION  
       [0009]     The present invention provides an apparatus and method for improved endoscopic retraction procedures. The invention permits safe and effective retraction of internal organs and tissue thereby providing protection to delicate structures during an endoscopic procedure.  
         [0010]     Retraction is accomplished with the present invention through the use of an inflatable bladder or membrane attached to an endoscopic sheathe. The membrane is sufficiently soft and flexible enough to avoid damage to internal organs and tissues, yet it is sufficiently inelastic and rigid so as to provide retraction when inflated.  
         [0011]     In accordance with one aspect of the present invention, there is provided an inflatable endoscopic retractor comprised of an inflatable membrane having an anatomical configuration designed to retract structures specific to the surgical procedure. For example, the membrane for use in an endoscopic biopsy would be configured to retract the cerebrum and cerebellum, as well as to provide protection thereto. The present invention is not limited to neurosurgical applications. Analogous anatomical membranes for use in other procedures include configurations for other anatomical structures; e.g. the kidney, bladder, pancreas and liver.  
         [0012]     When retraction during endoscopic surgery is desired, the endoscopic sheath is inserted into the body. The distal end of the inner tube is placed, under direct view, proximal to the anatomical structure that is the subject of the procedure. The membrane may be slightly inflated to assist in its proper positioning inside the body. Once the distal end of the inner cannula is properly positioned, the membrane is inflated with air or other gas or liquid, in an amount sufficient to retract the desired organ or other tissue and maintain and support the organ or tissue in its retracted position. After the endoscopic procedure is complete, the membrane is deflated and the endoscopic sheath is removed.  
         [0013]     In accordance with a second aspect of the present invention, there is provided an endoscopic sheath comprising a substantially rigid outer cannula, and a substantially rigid, elongated inner cannula. The inner cannula is of sufficient diameter to pass through the outer cannula and be manipulated along any axis therein. At least one, but preferably more, suspension strand connects the outer surface of the inner cannula to the inner surface of the outer cannula. The suspension strand can be substantially elastic to provide maximum mobility for the inner cannula within the outer cannula. In yet another embodiment, a plurality of suspension strands are positioned to connect the inner and outer cannulas such that the inner cannula assumes a resting position that is substantially parallel to the outer cannula.  
         [0014]     In accordance with another aspect of the present invention, there is provided a method of retracting internal tissue and organs using the retractor and sheathe described above. The inflatable membrane of the endoscopic sheath of the present invention significantly reduces the risks associated with retraction, such as thermal, electrical, or mechanical injury. In addition, it significantly reduces the chances of hemorrhage associated with direct surgery of neural tissue. The endoscopic sheathe is sufficiently small to allow its introduction into utilizing a small trocar. The sheath is normally introduced through a single small opening or burr hole. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which:  
         [0016]      FIG. 1  is a sagittal view of a patient with a pineal region tumor.  
         [0017]      FIG. 2  provides perspective views of the inventive apparatus.  
         [0018]      FIG. 3  is a sagittal view of a patient undergoing an endoscopic procedure wherein the inventive apparatus is introduced to the patient&#39;s body.  
         [0019]      FIG. 4A  is a sagittal view of a patient undergoing an endoscopic procedure wherein the membrane of the retractor is inflated.  
         [0020]      FIG. 4B  is a sagittal view of a patient undergoing an endoscopic procedure wherein the membrane of the retractor is inflated the inventive apparatus is shown in cross-section and the suspension strands can be seen.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and within which are shown by way of illustration specific embodiments by which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention.  
         [0022]     Referring to  FIG. 1 , there is shown a sagital view of a patient undergoing an endoscopic biopsy of the pineal gland, illustrating only one example in which the endsoscopic sheath and retractor  5  of the present invention might be utilized during endoscopic surgery. In the example shown, a extra-ventricular trajectory is taken. Endosurgical port A is shown, through which endoscopic sheath  5  is inserted. This allows the surgeon to view the internal tissues and organs in the surgical area.  
         [0023]     Sheath  5  of the present invention is inserted through the opening or port A made in the patient&#39;s body. A pair of endosurgical forceps may be inserted through surgical port A to aid in the positioning of the endoscopic sheath  5 .  
         [0024]     As illustrated in  FIGS. 1-3 , the inflatable retractor  10  of sheath  5  is used to constrain and retract the cerebrum and cerebellum to permit endosurgical access to the pineal region. It should be noted, however, that the principles of the present invention are not limited to any particular surgical procedure but may be applied to a wide variety of procedures and applications, including direct surgery.  
         [0025]     Referring now to  FIGS. 2-4 , there is shown one embodiment of endoscopic sheath  5  with inflatable retractor  10  of the present invention.  FIG. 2  illustrates retractor  10  mounted on outer cannula  20  suitable for use in endoscopic procedures. The length of outer cannula  20  is primarily dependent upon the type of procedure in which the retractor is to be used.  
         [0026]     Inner cannula  25  has a proximal or control end  25   a , and a distal or insertion end  25   b . Both outer cannula  20  and inner cannula  25  are preferably made of a material which will remain free from degradation, are easily sterilized, and are biocompatible. The shape of the distal or insertion end  25   b  is chosen to aid in preventing the puncture or other injury to internal organs and tissue when sheath  5  is being manipulated inside the patient&#39;s body. Proximal end  25   a  remains outside the patient&#39;s body during the procedure.  
         [0027]     Suspension strands  40  connect inner cannula  25  to outer cannula  20 , thereby allowing the movement of inner cannula  25  in three axis once outer cannula  20  is secured. Suspension strands  40  are preferably adapted to return inner cannula  25  to a home position, substantially parallel to outer cannula  20 , when no force is applied to inner cannula  25 . This arrangement allows inner cannula  25  to be freely moveable thereby enabling manipulation of the endoscopic device away from delicate structures.  
         [0028]     In addition to the cannula-housing shown in  FIGS. 2-4 , the present invention is also compatible with standard trocar-induced cannulas frequently utilized in endoscopic surgery. As such, the cannulas provide a port into the patient&#39;s body and a short tube for the insertion of endoscopic instruments. Thus, the principles of the present invention are not to be limited to any particular housing, cannula, or method of insertion into the patient&#39;s body.  
         [0029]     Still referring to  FIG. 2 , the inflatable retractor  10  consists of a long, inflatable balloon or membrane with an anatomical configuration designed to retract structures specific to the surgical procedure. The membrane of retractor  10  is comprised of a soft, flexible material which preferably does not absorb liquid and is easily sterilized, such as silastic, rubber, vinyl, polyethylene, or other polymeric material.  
         [0030]     Referring again to  FIG. 2-4 , there is shown a small-diameter hollow tube made of non-collapsible, flexible material which is connected to the membrane of retractor  10  at the it&#39;s proximal end  11 . This hollow tube permits the entry and exit of gas or liquid to and from the inflatable membrane. The proximal end of the tube connects to an inflation and venting device (not shown). This device can be any of a variety of devices, including, for example, a bulb-type or piston-type syringe, a gas cartridge, or a fluid pump.  
         [0031]     Operation Of The Sheath  
         [0032]     The operation of the inflatable endoscopic retractor as used in a biopsy of a pineal-region tumor will now be explained, as illustrated in  FIGS. 2 through 4 . The body is first prepared by creating a burr-hole within the skull of the patient. Endoscopic sheath  5  is inserted into the patient&#39;s body through the burr-hole in the selected trajectory. The trajectory may be a natural anatomical compartment, for example: CSF cisterns in closed procedures, or through brain tissue in open transventricular procedures.  
         [0033]     In this example, trocar  100  is positioned within inner cannula  25  prior to insertion. An endoscope (not shown) may also be inserted into the body to aid in visualizing the internal structures and to ensure the proper positioning. A pair of forceps  70  suitable for use in endoscopic surgery may be inserted to aid in the positioning of the sheath  5 . Trocar  100  is removed leaving inner cannula  25  free for insertion of an endoscope, for example. Distal end  25   a  of inner cannula  20  can be placed in optimum position under vision by the endoscope.  
         [0034]     As illustrated in  FIG. 3 , retractor  10  is mounted to outer cannula  20  and positioned, under direct view or with the help of an endoscope, within the patient&#39;s body. The membrane of retractor  10  may be slightly inflated to aid in its maneuvering. Retractor  10  can now be inflated against the surrounding neurovascular structure to reposition them away from endoscopic manipulations. With retractor  10  inflated and distal end  25   a  of inner cannula  25  positioned near the structure of interest, here the pineal region tumor, the endoscopic procedure can be performed while protecting the surrounding neurovascular structures.  
         [0035]     Retractor  10  is deflated, and the endoscope and sheath  5  are safely removed when the procedure is completed. Furthermore, the endoscopic sheath of the present invention provides for inspection of the working trajectory as the endoscopic devices are removed.  
         [0036]     It will be seen that the objects set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.  
         [0037]     It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween. Now that the invention has been described,