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  Traction trocar apparatus and methodUSPTO Application #: 20070118167Title: Traction trocar apparatus and method Abstract: The trocar system includes a cannula insertable through a body wall using an obturator having a distal tip. A traction tread disposed interiorly of the obturator inverts at the distal tip and extends proximally along the outer surface of the obturator or cannula. At the distal tip the tread can facilitate parting rather than cutting the tissue Along the outer surface, the tread can engage the tissue to pull it proximally along the advancing obturator. This produces counter forces which can result in a net proximal force facilitating distention of the abdominal wall and separation of the abdominal wall from internal organs The traction tread can be axially and/or radially continuous. An associated method of operation includes the steps of contacting the body wall with the traction tread at the distal tip, and engaging the body wall with the traction tread along wall portions facing the outer surface (end of abstract)
Agent: Applied Medical Resources Corporation - Rancho Santa Margarita, CA, US Inventors: Charles C. Hart, Edward D. Pingleton, John R. Brustad, Nabil Hilal, Raffi Pinedjian USPTO Applicaton #: 20070118167 - Class: 606185000 (USPTO) Related Patent Categories: Surgery, Instruments, Cutting, Puncturing Or Piercing, Puncturing Or Piercing The Patent Description & Claims data below is from USPTO Patent Application 20070118167. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of Invention [0002] This invention relates generally to trocar systems and more specifically to obturator apparatus and methods for placing a trocar cannula across a body wall [0003] 2. Discussion of the Prior Art and Related Technology [0004] It is generally well known that holes can be created through body tissue either by cutting the tissue or by mechanically parting the tissue along lines of weakness. Where tissue is cut, it is severed along a line, which is determined by the direction of the cutting implement. Where tissue is parted, it separates along natural tissue planes such as those defined by muscle fibers or differing layers of tissue such as skin and muscle. Tissue that is mechanically separated tends to heal better than tissue that is cut with tissue that is mechanically separated the healing process requires only that the affected tissues re-approximate each other with cut tissue, and in particular muscle fibers, the healing process must reconstruct the damaged tissue, often with resultant scaring and incomplete reconstruction. It has been shown for laparoscopic surgery in particular, that trocar wound sites of 10 millimeters in diameter and higher, made by cutting obturators, require suturing to prevent incisional hernias from occurring. It has also been shown that where the same size would site is created by expanding or parting the wound from a cut of 3 millimeters, for example, that the wound site does not require stitching and tends to heal faster. [0005] For laparoscopic surgery there is a requirement that instrument ports in the form of cannulas be placed in the patient's abdominal wall. These cannulas are then used as access ports for the surgeon to place instruments such as scissors and graspers. In the past these cannulas have been introduced by using a sharp cutting obturator, placed within the cannula, to cut a line or hole for, advancing the cannula through the abdominal wall. The obturator is then removed from the cannula and the cannula is left in place for the duration of the surgery. [0006] For most surgeries the cutting obturator is only used after the abdomen has been insufflated with carbon dioxide gas. There is then separation between the abdominal wall and the underlying anatomical structures and organs. Even with this separation, however; there is a risk that the patient will be injured by the sharp cutting tip of the obturator as it breaks through the abdominal wall. To help resolve this issue a variety of mechanical shielding mechanisms have been employed to cover the cutting element once it breaks through the abdominal wall. It has been noted and observed that even with these mechanical shield mechanisms that the risk is not completely eliminated and that the rigid shields themselves can cause damage to internal organs and structures. [0007] Other methods have been used as well. For example, optical trocars have been provided with a cleat plastic cutting tip. This allows the surgeon to view the tissue layers as they are cut, and in principle to better, control the timing of insertion forces. These plastic tips, however, are not as sharp as the metal bladed variety and therefore require a higher insertion force which in turn increase abdominal wall distortion. This distortion or tenting brings the obturator tip into closer proximity with the internal organs and increases the chances for potential damage. The wound created by such a device is still a cut and not a mechanical separation, as it still suffers from the above-mentioned disadvantages. [0008] Another manufacturer employs a multistage system whereby a sheath is inserted over a veress needle. The needle is then removed and a conical obturator, placed inside a cannula, is inserted through the sheath thereby expanding it to the desired cannula size. The obturator is then removed leaving the cannula in place. This offers the advantage of a smaller initial incision with the veress needle. However, the needle still presents a risk to internal organs, and the system is more expensive and complex than those associated with the cutting obturator devices. [0009] In all of these systems of the past, a cutting element is employed to either create the final size of the wound site or to make a smaller initial wound site that is then expanded to the final size. The use of sharp cutting elements common to all systems presents an unavoidable risk to the patient. SUMMARY OF THE INVENTION [0010] These deficiencies of the prior art are overcome with the present invention which provides for the parting rather than cutting of tissue, and, the use of opposing radial forces which precede the tip of the obturator shaft. After the tissue is parted, it is drawn proximally along the outer surface of the shaft as the shaft is moved distally through the body wall. The resulting counter forces can produce a net proximal force on the body wall with a minimal distal or penetration force. [0011] In a preferred embodiment a tubular mesh sleeve is initially disposed in the hollow shaft of the obturator. This sleeve is pulled out of a hole at the tip of the obturator shaft and drawn radially and proximally along the outer surface of the shaft. The mesh sleeve inverts at the distal tip facilitating its movement interiorly of the shaft and its traction with the parted tissue exteriorly of the shaft. [0012] In one aspect of the invention, an apparatus is provided for creating an opening through body tissue. The apparatus includes a shaft having an axis and a channel extending axially between a proximal end and a distal end. The shaft has a distal tip and a hole in the tip communicating pith the channel of the shaft. Portions of the tip define a leading surface of the tip. Means is disposed along this leading surface and is moveable relative to the tip for creating generally opposing forces on the body tissue which tend to part the body tissue and thereby create the opening through the body tissue. [0013] In another aspect of the invention, a surgical instrument is used for creating an opening through an abdominal wall retaining internal organs. The instrument includes a shaft having an outer surface and a tip. A sheath initially contacting the body tissue generally at a point extends proximally from the point along the outer surface of the shaft. The shaft is operable to create a distal force on the body tissue while the sheath is operable to create a proximal force on the body tissue. The proximal force is greater than the distal force in order to create a net proximal force on the abdominal wall tending to separate the abdominal wall from the internal organs as the opening is created. [0014] In another, aspect of the invention, a flexible sheath having a tubular configuration extends from an axial channel of the shaft through the distal tip of the shaft. A handle is attached to the sheath exteriorly of the shaft and is moveable proximally relative to the shaft to withdraw the sheath from the channel and to progressively invert the sheath at the tip of the shaft. [0015] In another aspect of the invention, the shaft of the surgical instrument has a tubular configuration with an outer surface, an axial channel, and a distal tip. At least one flexible traction tread is carried within the axial channel and extends outwardly of the shaft at the distal tip. A handle attached to the traction tread exteriorly of the shaft is moveable proximally to withdraw the traction tread distally through the distal tip. [0016] An associated method of operation includes even further aspects of the invention. For example, a method for creating an opening in body tissue includes the steps of providing opposing traction treads extending from the axial channel of the shaft outwardly through the hole in the tip of the shaft. The body tissue is contacted with the traction treads at the tip of the shaft and the traction treads arc moved radially outwardly from the hole in the tip. During this moving step, the body tissue is engaged at the tip to produce parting forces on the body tissue tending to separate the body tissue and thereby create the opening through the body tissue. [0017] In another method of operation, first and second cannulas are inserted through body tissue by providing an obturator having a shaft with an outer surface and a traction tread moveable relative to the outer surface. Placing the obturator in the first cannula, the body tissue is engaged with the tread and the tread is moved relative to the outer surface of the shaft to facilitate penetration of the body tissue by the shaft and the first cannula. The obturator is then removed from the first cannula and placed in the second cannula where again the traction thread engages the tissue and facilitates penetration of the body tissue by the shaft in the second cannula. Removing the obturator from the second cannula leaves both the first cannula and the second cannula operatively disposed across the body wall. [0018] In another method associated with the invention, removal of a trocar cannula from a body wall is facilitated by placing a mesh sleeve between the cannula and the body wall. The sleeve is provided with properties which exert a radial force on the cannula tending to resist removal of the cannula from the body wall. However, an axial force can be applied to the sleeve to reduce the radial force of the sleeve on the cannula. During this step of applying the axial force, the cannula can be removed from the body wall. [0019] In a method for inserting an obturator, the obturator is provided with a shaft having an outer surface and a traction tread moveable along the outer surface of the shaft. The tread is carried within the shaft. As the obturator is moved through the body wall, a first force is applied to the obturator in a first direction and a second force is applied to the obturator in a second generally opposing direction. As the obturator is moved distally relative to the body wall, it engages wall portions which face the outer surface of the shaft and pulls those wall portions proximally along the shaft. [0020] These and other features and advantages of the invention will be better understood with reference to preferred embodiments of the concept and reference to the associated drawings. DESCRIPTION OF THE DRAWINGS [0021] FIG. 1 is a side elevation view of a patient with insufflated abdomen and trocars in the process of being placed using the trocar system of the present invention; Continue reading... Full patent description for Traction trocar apparatus and method Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Traction trocar apparatus and method patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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