Patent Document

CROSS-REFERENCE 
     This application claims the benefit of U.S. Provisional Application No. 60/822,542 filed Aug. 16, 2006, entitled System and Method for Performing Selective Dissection of Lung Tissue which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention is directed to devices, methods, systems and kits that enable dissection of lung tissue in a fast and safe manner. In particular, it relates to an invention and methods that enable minimally invasive and selective dissection of tissue to remove diseased tissue from healthy tissue without damaging blood vessels or airways. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to devices, methods, systems and kits that enable selective dissection of lung tissue to remove diseased tissue from healthy tissue without damaging blood vessels or airways. The invention and methods enable minimally invasive lung surgery procedures by providing a device and method to perform automated dissection that discriminates against traumatizing critical lung tissue. 
     Relatively few thoracic procedures are performed using minimally invasive or video assisted thoracic surgical techniques (VATS) even though they are well known to provide benefit to the patient by minimizing trauma and speeding recovery compared to open chest procedures. This is due, at least in part, to the fact that there are only a few available instruments designed specifically to enable thoracic procedures in this way. 
     Current clinical practice to remove lungs, lung lobes or lung tissue segments involve opening the chest by cutting the sternum or by spreading the ribs. Many times ribs are broken and often segments are surgically removed during these procedures. The orthopedic trauma alone presents considerable pain and it can complicate the recovery process with patients. Thoracic pain of this magnitude complicates the task of recovering a patient from general anesthesia since the body acclimates to forced ventilation and the pain can interrupt natural chest rhythm. Patients benefit dramatically from procedures that are performed through small incisions or ports in the chest without causing this orthopedic trauma. 
     The bulk of the procedural time and effort required to surgically remove lung tissue entails dissection of tissue away from critical structures such as arteries, veins and airways so they can be closed off properly and then transected. Currently, surgeons use standard forceps, scissors, and scalpel instruments to tease tissue away from these structures. This work is dangerous because the vasculature is coupled directly to the heart and a mistakenly lacerated vessel results in large, and sometimes, uncontrollable hemorrhage. 
     Dissection using manual instruments is slow because the physician must constantly anticipate stressing a critical structure and possibly rupturing the tissue. A typical technique involves plunging a scissor type instrument forward and then spreading it to tear tissue apart. It is slow, dangerous and requires good visualization and surgical skill to avoid complications. 
     Hence, there is a need for a device that is automated and safer and allows the physician to concentrate less on each stroke of a manual instrument and allows for a more minimally invasive approach. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system, device and methods to perform selective tissue dissection. 
     The system includes a port or small hole-making instrument to deliver the invention through a small entry site in the chest to minimize orthopedic trauma. 
     In another embodiment, the system includes the invention and a scope instrument to enable the procedure to be performed minimally invasively. Open chest procedures may be performed through openings larger than 10 inches wide. However, the invention can be practiced through openings that are less than 10 inches across. 
     The invention is configured in a way that very small bits of tissue are dissected with each stroke of the device. The dissecting element may be grooved with, for example, a maximum groove width that is only opened to allow for the entry of tissue that is less than 5 mm, less than 3 mm, smaller than 1 mm or less than 0.5 mm and this would make it difficult for airways or critical veins or arteries to advance into a cutting area on the dissector element. For purposes of analogy in understanding the operation of the device of the invention, the device of the invention performs analogously to a hair shaver that is adapted to prevent cutting structures larger than a target size, such as tubular structures that are 0.5 mm in diameter or larger. 
     In a configuration of the dissector element or housing is configured is such that all sharp edges are configured within the groove feature. In some embodiments, some or all edges external to the grooves are dull although they may be tapered to enhance blunt dissection properties. Some features may be sharpened on the inside of the groove or outside, or both, in order to snag tissue to allow the reciprocating motion to stress the tissue to pull it apart, cut or dissect. 
     The size of the dissection action with each stroke is reduced to make the dissection perform safely but slowly. To enhance the speed of dissection, the invention should be driven by a work energy source that could include a motor driven by battery power, direct current, alternating current, air pressure, vacuum, electromotive induction or other means to cause linear or rotary motion. The rate of motion of the dissecting element can, for example, be dictated by the coupled mechanism that is driven by the motor. Typically, the dissecting element or elements is driven faster than, for example, 1 hertz. A rate higher than 10 hertz can also be used, as well as a rate more than 30 hertz or more than 50 hertz. 
     In an embodiment, the invention is configured long and thin so that it can fit through small holes in the chest. The effective length or reach of the device in an embodiment would be longer than 50 mm with a diameter less than 75 millimeters (mm). The diameter could be less than 25 mm but less than 20 mm. 
     The components of the invention be made of plastics, metals or both. The motor must be controllable by the physician at any time by way of actuating a switch or valve in line between the work energy source and the power source that drives the work source. 
     The physician can control the tilt or orientation of the dissecting element as the procedure progresses. In a configuration a mechanism may allow the physician to push a knob to control a mechanism that tilts or rotates or translates the dissector section of the invention from side to side. This will allow the physician to enter the chest from a single port or hole in the chest and maneuver the invention to the tissue in a multitude of trajectories. 
     In a method embodiment, a lobectomy surgery is performed using the invention to make dissections to separate adjacent pleura to complete the fissures between the lobe that is to be removed and adjacent lobes. The method includes the step of locating large airways, arteries and veins larger than approximately 0.5 mm or larger in diameter (e.g. generically referred to as structures) and carefully dissecting out of the lung tissue and/or tumors so they can be reliably clipped, stapled or sealed off with glue or other methods. As will be appreciated by those of skill in the art, failure to identify the critical structures in the lung may result in accidental laceration when the lobe is completely cut away from the adjacent lungs. Laceration or any procedure that allows for rupture of the arteries in this region greatly increases the risk of patient death since they transport the majority of the human cardiac output. Laceration could cause an immediate and uncontrollable hemorrhage that could result in patient death. 
     An additional method is directed to performing a lobectomy of a lung which comprises providing a surgical instrument with a source of work energy that is coupled to a dissecting member extending from the forward portion of the instrument; activating the source to induce motion of the dissecting member; contacting the dissecting member to adjacent pleurae along a fissure; and dissecting a lobe of lung away from a tubular lung structure. Additionally, the method can include visualizing the lung with an optical instrument, such as an endoscope. Tubular lung structure suitable for dissection include, but are not limited to bronchi, dissectible airways, veins and arteries. In some instances it may be desirable to adjust the projection of the dissection member into different trajectories. 
     An additional aspect is directed to a kit for removing a portion of a lung from structures of the lung. The kits comprises: a surgical instrument comprising an elongated housing having a longitudinal axis, a forward portion and a rearward portion of the housing, and a dissecting member extending from the forward portion of the housing; and a hole-making instrument for making an entry site to access a target lung section for the surgical instrument. The surgical instrument can be any suitable surgical instrument adapted and configured to remove a portion of a lung from structures of the lung. Additionally, the kit can be configured to include a variety of other components, including, for example, an optical instrument for communicating a visual of a target of the surgical instrument, such as an endoscope. 
     Incorporation by Reference 
     All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which: 
         FIG. 1  illustrates an anterior view of the human lungs and bronchi tree; 
         FIG. 2  illustrates an anterior view of the left lung to illustrate where the lobes are separated during a typical lobectomy surgery. Tissue is dissected away from the primary bronchus; 
         FIG. 3  illustrates the relative position of surgical instruments that are used for video assisted thoracic surgery (VATS) with the invention making the dissection of the tissue at the primary bronchi; 
         FIG. 4  illustrates the primary bronchus after it has been stapled or clipped and the lower lobe has been removed; 
         FIG. 5  illustrates the invention and main components in a cut away view; 
         FIG. 6  is a detailed drawing of the working distal end of the invention; 
         FIG. 7  is an isometric view of a dissecting element or dissecting housing; 
         FIG. 8  is a top view of a dissecting element or dissecting housing; 
         FIG. 9  is a top view of an alternative dissecting element or dissecting housing; and 
         FIG. 10  is an isometric view of an alternative dissecting element or dissecting housing. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates an anterior view of the human lung  42  and trachea  1 . The trachea extends into the chest cavity to bifurcate into the primary bronchi  2  to then branch into the lung lobes and become bronchioles and small airways  9 . The lungs are divided by fissures  10  that are lined with a membrane called the visceral pleura  3 . The left side of the human chest contains the superior lobe  7  and the inferior lobe  8 . The right side of the human chest contains the inferior lobe  4 , the middle lobe  5  and the inferior lobe  6 . 
       FIG. 2  illustrates the left side of the human chest cavity with the superior lobe  7  and inferior lobe  8 , fissures  10 , tissue that has been dissected away from the primary bronchi  12  where the surgeon will close off the bronchi and cut the lobe away  11 . Lung tissue  12  must be dissected away from tubular Structures in the lung to access completely around these Structures to apply a closing or blocking device. The tissue  12  is dissected completely around the Structure approximately 25 mm down the length of the Structure. The cleared segment is typically longer than 10 mm. Sections longer than 5 mm or longer than 3 mm are also suitable alternatives. 
       FIG. 3  illustrates a device  29  in use, engaging a dissecting member  19  to remove lung parenchyma away from bronchi  9 . The other instruments are shown to present a typical video assisted thoracic surgery (VATS) system and how it would be used to perform a minimally invasive lobectomy. The device  29  is inserted through a small hole in the chest  41 . Tissue is tensioned using a tensioning device  38  with teeth  39  that engage dissected tissue. An optical element  35  is inserted through a port  40  to communicate a visual image of the procedure to the camera  36  and to a monitor via a video cable  37 . The figure further illustrates how the device dissects to separate the superior lobe  7  from the inferior lobe  8  so that the inferior lobe can be removed. The dissection that is shown must be performed on all airways, arteries and veins that communicate through or into the lobe that is being treated. The illustrated devices and methods are applicable for dissecting tissue from any of the aforementioned Structures. The invention can be equally useful for any surgical procedure in the thoracic cavity such as adhesion cutting, pneumonectomy, lobe segment removal, lung volume reduction surgery and other procedures to eliminate spontaneous pneumothorax, tumor removal, and general lung repair. The invention can be utilized in open surgery or introduced through a port or small hole in the chest. 
       FIG. 4  is an anterior view of a chest cavity wherein the bronchi branch  11  that led to the inferior lobe is clipped  14  to occlude the branch and the lobe has been removed to leave only the superior lobe  7  in the chest. 
       FIG. 5  illustrates a cut away view of one configuration of the invention. The surgical system  29  operates by delivering work energy to a distal dissecting element to selectively dissect tissue away from specifically targeted lung tissue that must be preserved. The user can deliver work energy manually or control, via a switch  14 , electrical current from a wall outlet or battery  13  to a motor  15  by way of wires  28  in the invention. The motor rotates the drive shaft  16  that is coupled to an eccentric cam  17  that intermittently loads the follower plates  18  to move the dissecting element  19  from side to side in a reciprocating manor. One or more dissector elements may be driven in a synchronized way or they may be driven in opposing directions to provide shear force on the lung tissue. The dissecting elements may be made of metal, plastic, ceramic or other dimensionally stable materials. The dissector element edge may be made of or coated with an abrasive material to enhance dissecting speed and efficiency. Coatings may be selected from the group of materials including plated, electroplated, sputtered, or vapor deposited metals, ceramics, glasses, plastics, fibrous materials such as carbon, oxides or other know substances that are used to provide abrasive surfaces. The dissecting element is guided by a dissector housing  20  that pivots about pin  21  and is stabilized and controlled by a pull rod  23  that is coupled to the dissector housing via coupler pin  22 . The dissector housing may be adapted to hold tissue from moving to maximize the relative motion between tissue and the dissecting elements. Grooved tooth profiles are shown that enable fixation. The pull rod  23  incorporates a toothed rack  24  that engages a toothed gear  25  that is coupled to control knob  26 . Rotation of the control knob adjusts the pivot angle of the dissecting system. The entire mechanism is housed in housing  34 . The cutting mechanism may be detachable to be replaced with new cutters, or blades of different dimensions for different tasks during the procedure. 
     The power source can be selected from the group of 110 or 220 volt alternating current power or any direct current voltage that can be produced from a battery system such as Nickel Cadmium (NiCd), Nickel Metal Hydride (NiMH), Lithium Ion (LiON) or Smart batteries that have internal microprocessor circuits which help manage battery energy, report the state of the charge, predict running time or track battery usage. The mechanical parts of the invention can be made from metals, plastics, ceramics or a combination of these. The motor may comprise a gear reduction component or be coupled to one. A stop lock may be coupled to the pivot control mechanism. The motor may be a source for ultrasonic energy to drive the dissecting element at high frequencies above 10,000 hertz. A motor and gear reduction may slow the rotational speed to 10 hertz or less to enable slow dissection and physician feedback throughout the process. Any speed between the two would be ideal. 
     The invention shown in  FIG. 5  illustrates a mechanism that can perform dissection by way of a moving dissector element using reciprocal motion. Another embodiment is a system that drives a rotary dissector element whereby the tooth spacing of the dissecting element or the dissecting housing accomplishes the same result as the reciprocating dissecting element. 
       FIG. 6  is a detailed view of the pivot mechanism showing the housing  27 , drive shaft  16 , cam  17 , follower plate  18 , dissecting element  19 , dissector housing  20 , coupler pin  22 , pin  21  and pull rod  23 . The pivot mechanism allows for the physician to controllably change the trajectory that the dissector operates. By manipulating this control, the physician can adjust the relative angle between the dissector element and the tissue or Structure that is being trimmed. Adjustment such as this allows the invention to be inserted into small ports or various locations between ribs with a high level of success to locate the point of dissection with a favorable angle of attack. The dissector can also be adjusted to one side or the other in the axis that the reciprocal motion takes place. This would be into or out of the plane of the illustration. 
       FIG. 7  illustrates a configuration of a dissecting element  19  or dissector housing  20  that features grooved teeth  32  to engage tissue. The teeth are made with a tapered profile  31  and can be sharp at the extreme tips or faceted  30  to eliminate the possibility of cutting into a tubular Structure in the lung. 
       FIG. 8  shows a top view of a dissecting element  19  or a dissector housing  20  that features grooved teeth  32  with facets  30  and sharpened blade sections  33  only on the inside of each groove. This ensures that cutting is performed only on tissue that is allowed inside the tooth groove. The width of the groove dictates the size of Structure that can be advanced into the cutting groove. The groove spacing can be the spacing from the start of one tooth to the start of the adjacent tooth. Typically the groove spacing is less than 5.0 mm, less than 3.0 mm, less than 1.0 mm, or less than 0.5 mm. 
       FIG. 9  illustrates a top view of a dissecting element  19  or a dissector housing  20  that features no cutting blade edges. This configuration is intended to engage tissue without cutting. The relative motion between the dissector element and the dissector housing will pulls apart soft lung tissue without cutting into critical Structures such as the arteries, veins, bronchi or dissectible airways. 
       FIG. 10  is an isometric view of another configuration of dissecting element  19  or dissector housing  20  that is tapered  31  and features angular surfaces to offset the grooved tooth section from the mounting plane  43 . This configuration allows the toothed section to be mated closely with either the complimentary dissecting element or dissecting housing. 
     An additional aspect is directed to a kit for removing a portion of a lung from structures of the lung. The kits can be configured to comprise any of the devices or components described above with respect to  FIGS. 3-10 . The kits comprise, for example, a surgical instrument comprising an elongated housing having a longitudinal axis, a forward portion and a rearward portion of the housing, and a dissecting member extending from the forward portion of the housing; and a hole-making instrument for making an entry site to access a target lung section for the surgical instrument. The surgical instrument can be any suitable surgical instrument adapted and configured to remove a portion of a lung from structures of the lung. Additionally, the kit can be configured to include a variety of other components, including, for example, an optical instrument for communicating a visual of a target of the surgical instrument, such as an endoscope, a tensioning device, etc. 
     In a method embodiment, lobectomy surgery is performed using the invention to make dissections to separate adjacent pleura to complete the fissures between the lobe that is to be removed and adjacent lobes. The method includes the step of locating large airways, arteries and veins larger than approximately 0.5 mm or larger in diameter (e.g. generically referred to as structures) and carefully dissecting out of the lung tissue and/or tumors so they can be reliably clipped, stapled or sealed off with glue or other methods. As will be appreciated by those of skill in the art, failure to identify the critical structures in the lung may result in accidental laceration when the lobe is completely cut away from the adjacent lungs. Laceration or any procedure that allows for rupture of the arteries in this region greatly increases the risk of patient death since they transport the majority of the human cardiac output. Laceration could cause an immediate and uncontrollable hemorrhage that could result in patient death. 
     An additional method is directed to performing a lobectomy which comprises providing a surgical instrument with a source of work energy that is coupled to a dissecting member extending from the forward portion of the instrument; activating the source to induce motion of the dissecting member; contacting the dissecting member to adjacent pleurae along a fissure; and dissecting a lobe of lung away from a tubular lung structure. Additionally, the method can include visualizing the lung with an optical instrument, such as an endoscope. Tubular lung structure suitable for dissection include, but are not limited to bronchi, dissectible airways, veins and arteries. In some instances it may be desirable to adjust the projection of the dissection member into different trajectories. 
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Technology Category: 1