# Patent

## Title
Method for anchoring and sealing a cannula assembly to the body of a patient

## Abstract

A cannula assembly for use in laproscopic surgery includes a cannula having a proximal end for use in orientating the assembly into an abdominal cavity, a distal end for insertion into a patient, and a passage through which surgical instruments can be inserted. An expandable feature in the form of an anchor is located toward the distal end of the cannula and is selectively expandable and collapsible. The feature in its expanded state prevents withdrawal of the cannula. A collar is pushed distally until it releasably cinches to the outside of the abdominal cavity thereby creating an airtight seal and stabilizing the assembly. The collar has a friction fit with the cannula designed to prevent excessive force against the cavity walls.

## Background
RELATED APPLICATIONS
This application is a divisional of U.S. application Ser. No. 14/195,395, filed Mar. 3, 2014 (now U.S. Pat. No. 9,155,550); which is a continuation of U.S. application Ser. No. 13/913,120, filed Jun. 7, 2013 (now abandoned); which is a continuation of U.S. application Ser. No. 12/802,032, filed May 28, 2010 (now U.S. Pat. No. 8,466,659); which is a continuation of U.S. application Ser. No. 11/430,431, filed May 9, 2006 (now abandoned); which is a divisional of U.S. application Ser. No. 10/680,973, filed Oct. 7, 2003 (now U.S. Pat. No. 7,041,055); which claims the benefit of U.S. Provisional Application No. 60/416,665, filed Oct. 7, 2002; U.S. Provisional Application Nos. 60/424,752; 60/424,754; and 60/424,755, each filed Nov. 8, 2002; U.S. provisional Application Nos. 60/425,506; 60/425,522; and 60/425,523, each filed Nov. 12, 2002; and U.S. Provisional Application No. 60/439,759, filed Jan. 13, 2003; all of which are incorporated by reference herein.


BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to a stabilized cannula adapted to seal against the loss of gas pressure from a body cavity of a patient during a surgical procedure.
Description of the Prior Art
The insertion of a cannula into an abdominal cavity during laparoscopic surgery is generally accomplished using one of two methods. In the first method, a hollow needle is inserted into the body cavity prior to the insertion of the cannula so that the cavity can be expanded with a gas, such as carbon dioxide. Thereafter, the cannula is inserted along with a removable sharp obtruator. The obtruator blade cuts through the abdominal wall allowing the surrounding cannula to penetrate into the interior of the cavity. The obtruator is then removed leaving an entry port for various laparoscopic tools to be inserted into the cavity. The cannula is equipped with a seal at its proximal end to ensure that the cavity remains pressurized with the insertion and removal of various instruments. Pressure loss between the cannula and the cavity wall is reduced by the tightness of the fit between the cannula and the cavity wall because the outside diameter of the cannula is larger than the obtruator entry wound. Generally, the obtruator used in this method is equipped with a spring-activated shield that is designed to cover the blade as soon as the interior wall is penetrated to avoid inadvertent puncturing of the organs present inside the cavity. These shields sometimes fail to close quickly enough to avoid injuries, particularly if an organ such as the bowel is attached to the cavity wall.
A known method that avoids injuries associated with the obtruator shield involves direct incision of the wall by the surgeon. Using a small scalpel, the surgeon makes an incision through the cavity wall into the abdominal cavity and inserts a finger into the cavity to feel for organs that might be attached to, or near the abdominal wall. Upon a determination that no organs are attached to the abdominal wall, a cannula with an obtruator having a blunt tip is inserted through the cut. After placement of the cannula, the obtruator is removed. The purpose of the blunt tip of the obtruator is to guide the cannula through the cut down to wound.
Both of the above described methods of insertion are prone to gas leakage and the lack of a proximal-to-distal stability of the cannula. Various techniques have been attempted to minimize these problems. Known anchors for use with laparoscopic cannula have employed threaded sleeves adapted to be secured to the cannula and screwed into a laparoscopic puncture opening to secure the instrument in place. An anchor of this type is found in U.S. Pat. No. 5,217,441. U.S. Pat. No. 5,002,557 to Hasson discloses an inflatable balloon that seals the cannula against the inside wall of the cavity and stabilizes the cannula by employing a tapered collar that cinches against the outside wall of the cavity, in effect sandwiching the cavity wall between the collar and the inflated balloon. The Hasson device provides a sufficient seal and adequate cannula stability, but is difficult to operate. The balloon must be inflated with an external hypodermic syringe or other means through a stop cock. Additionally, sealing the cannula with the cavity wall involves three steps: inflating the balloon, pushing a tapered collar snugly against the external surface of the cavity wall, and securing the collar in place with a set screw. U.S. Pat. No. 5,697,946 to Hopper et al. discloses a balloon-anchoring device that does not require the use of a proximal collar, but instead relies on a portion of the inflating surface to come in contact with the entry wound, thereby wedging the cannula into position. The Hopper device also involves an external inflation device such as a hypodermic syringe connected to the cannula by a stop cock or check valve.
U.S. Pat. No. 5,330,497 to Freitas et al. describes an anchored cannula that uses an expandable mushroom-shaped anchor that in one embodiment opens when the user turns a detented actuator. The anchor cinches-up against the peritoneum when a seal is forced distally. The Freitas device offers an improvement over threads, but still suffers from several drawbacks. In particular, the Freitas device is unduly complex at least in that it requires multiple steps in order to expand the anchor and seal the external cavity wall. A multiplicity of steps during a surgical procedure can lead to a serious inefficiency. Devices that are simple to operate make the procedure more efficient and lead to less errors. Therefore what is needed is a simple, easy-to-use cannula anchoring and sealing device and method for use in laparoscopic surgery.
SUMMARY OF THE INVENTION
In accordance with the purposes of the present invention, as embodied and broadly described herein, a cannula assembly of this invention is provided for permitting the insertion of instruments into a body cavity. The cannula assembly includes a proximal end, a distal end, and a longitudinal axis, an inner sleeve, an outer sleeve coaxial with the inner sleeve, and a collar. The outer sleeve is fixedly attached to the inner sleeve at the distal end of the cannula and has an exterior surface. The outer sleeve forms an anchor that is radially expandable from the longitudinal axis from a retracted position to an expanded position to anchor the cannula assembly to the body of a patient. The collar has an internal surface adapted to form a friction fit with the exterior surface of the outer sleeve to permit the collar to move a portion of the outer sleeve relative to the inner sleeve and move the anchor from the retracted position to the expanded position when the collar is moved toward the distal end of the cannula assembly. The friction fit between the collar and the outer sleeve is configured to permit the collar to move relative to the outer sleeve only toward the distal end of the cannula assembly when the anchor is in the expanded position.
In accordance with the purposes of another embodiment of the present invention, as embodied and broadly described herein, a method of this invention is provided for anchoring and sealing a cannula assembly to the body of a patient. The method includes providing the cannula assembly having a proximal end, a distal end, a radially expandable anchor proximate the distal end, and a longitudinally movable collar; inserting the cannula assembly to a depth sufficient to place the anchor in a retracted position within the patient; and expanding the anchor by moving the collar toward the distal end of the cannula assembly.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view of a cannula assembly according to one preferred embodiment of the present invention having an anchor in a retracted position;
FIG. 2 is a side elevation view of the cannula assembly of FIG. 1 with the anchor deployed in the abdominal cavity in an expanded position and a collar distally applied against the exterior of the abdominal cavity;
FIG. 3 is a fragmentary cross-sectional side view of the cannula assembly of FIG. 1 with the anchor shown in the retracted position; and
FIG. 4 is a fragmentary side elevation view of the cannula assembly of FIG. 1 with the anchor shown in the expanded position.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
FIGS. 1-4 show a trocar cannula assembly for use with the present invention generally referred to by the number 100. As shown in FIG. 1, cannula assembly 100 includes a cannula 102 having a distal end 104, a proximal end 106 opposite distal end 104 along a longitudinal axis L, an inner sleeve 108, and an outer sleeve 110 that is preferably coaxial with inner sleeve 108; and a movable annular collar 112.
As shown in FIG. 3, inner sleeve 108 has an interior surface 114 forming a passage 116 through which one or more instruments may pass, and an exterior surface 118. Referring again to FIG. 1, inner sleeve 108 has a proximal portion 120 that preferably includes a valve and/or seal to maintain pressure when the cannula is inserted into a pressurized cavity.
As shown in FIGS. 1 and 3, outer sleeve 110 has an interior surface 122 and an exterior surface 124. At least a portion of interior surface 122 is preferably adapted for slidable engagement with exterior surface 118 of inner sleeve 108. Outer sleeve 110 forms an anchor 126 preferably located toward distal end 104 of cannula 102. Anchor 126 provides stability to the cannula assembly when deployed within the abdominal cavity, as will be described in more detail below.
FIG. 3 shows anchor 126 preferably having a plurality of finger hinges 128 that are each separated by a slit 130. When anchor 126 moves from a retracted position shown in FIG. 3 to an expanded position shown in FIG. 4, fingers 128 radially expand away from longitudinal axis L of cannula 102 to anchor the cannula assembly to the patient. In order to prevent internal tissue from becoming entangled within fingers 128, anchor 126 preferably includes a flexible cover membrane 132. Cover 132 may be resilient to bias anchor 126 to the retracted position to permit easy insertion of cannula 102 into the abdominal cavity.
Inner sleeve 108 and outer sleeve 110 are preferably joined at distal end 104 of cannula 102 by conventional bonding materials. It will be appreciated by those skilled in the art that other ways to join the inner and outer sleeves together, whether chemically (e.g., glue), physically (e.g., ultrasonically weld or heat application), or mechanically, may be used and are within the broad scope of the present invention.
FIG. 1 shows an annular collar 112 preferably surrounding at least a portion of exterior surface 124 of outer sleeve 110. Annular collar 112 preferably has an internal surface that forms a friction fit with exterior surface 124 to sealingly engage the outer surface of the body cavity when anchor 126 is inserted into the patient and deployed. Preferably, annular collar 112, outer sleeve 110, and inner sleeve 108 are constructed such that the force of the friction fit between annular collar 112 and outer sleeve 110 is greater than the friction force acting between outer sleeve 110 and inner sleeve 108. This may be accomplished, for example, by selecting a material and snugness of fit between annular collar 112 and exterior surface 124 of outer sleeve 110 and the fit between internal sleeve 108 and outer sleeve 110. This permits inner sleeve 108 to move relative to outer sleeve 110 before annular collar 112 will move relative to outer sleeve 110. The interaction between inner sleeve 108, outer sleeve 110, and annular collar 112 is described in more detail below. It will be appreciated that annular collar 112 may exist in a variety of shapes and sizes, and need not completely surround outer sleeve 110 in order to function for its intended purpose.
Having described the physical components of one preferred embodiment of the present invention, a method for its operation will now be described. Returning now to FIG. 1, cannula assembly 100 is positioned proximate the surgical site to be operated upon, such as the abdominal cavity, with annular collar 112 in its proximal-most position and anchor 126 in the retracted position. An obtruator is placed through proximal portion 120, into passage 116 of inner sleeve 108, and beyond distal end 104 of cannula 102.
The distal-most end of the obtruator is generally blade-shaped and punctures the abdominal cavity, allowing cannula 102 to be forced into the defect. Cannula 102 is inserted into the puncture to a sufficient depth so that anchor 126 is below the peritoneum of the abdominal cavity. The obtruator is then removed from cannula 102.
With cannula assembly 100 properly positioned and inserted into the abdominal cavity, anchor 126 is deployed. Holding proximal portion 120 stationary, annular collar 112 is moved away from proximal portion 120 toward distal end 104. Annular collar 112 is preferably tightly fitted around external surface 124 of outer sleeve 110 to form a friction fit such that movement of annular collar 112 will cause a corresponding movement of a movable portion 134 of outer sleeve 110, which includes anchor 126. As annular collar 112 moves in the distal direction, movable portion 134 of outer sleeve 110 runs against a stationary portion 136 of outer sleeve 110, which is joined to inner sleeve 108 at distal end 104. Finger hinges 128 of anchor 126 radially expand away from longitudinal axis L to deploy anchor 126 into an arc shape so that anchor 126 moves from the retracted position shown in FIG. 3 to the expanded position shown in FIG. 4. As annular collar 112 and outer sleeve 110 continue to move distally, anchor 126 becomes fully deployed.
Once anchor 126 becomes fully deployed, movable portion 134 of outer sleeve 110 reaches its maximum longitudinal distance of travel and becomes stationary. At this point, the force of the friction fit between annular collar 112 and outer sleeve 110 is overcome by the force being applied to move annular collar 112 toward distal end 104. Annular collar 112 begins to move relative to outer sleeve 110 and cinches-up against the outer surface of the abdominal wall as shown in FIG. 2. After annular collar 112 is sufficiently pressed against the skin so that both sides of the abdominal cavity are sealed between annular collar 112 and anchor 126, annular collar 112 and proximal portion 120 are released.
While released, annular collar 112 and anchor 126 maintain a compression of the abdominal wall between them. Movement of annular collar away from the abdominal wall is retarded by the friction fit between annular collar 112 and outer sleeve 110. Anchor 126, owing to the resiliency of membrane 132 and to the elasticity of fingers 128, supplies a force that tends to restore the position of outer sleeve 110 relative to inner sleeve 108 to its original position. The surfaces and/or materials of outer sleeve 110 and inner sleeve 108 are designed such that the friction force between them counters the restoring force of anchor 126. Thus, after annular collar 112 is moved distally and anchor 126 is deployed, the friction force between inner sleeve 108 and outer sleeve 110 is larger than the restoring force being exerted from anchor 126 such that the relative position of inner sleeve 108 and outer sleeve 110 is maintained once cannula assembly 100 is released. A sufficient seal between anchor 126 and annular collar 112 is maintained in part because the force of the friction fit between annular collar 112 and outer sleeve 110 is greater than the friction force acting between inner sleeve 108 and outer sleeve 110, which in turn acts to overcome the force biasing anchor 126 to the retracted position.
After the surgical procedure, cannula assembly 100 is removed from the abdominal cavity by moving annular collar 112 toward proximal end 106 of cannula 102. Because the friction force of the friction fit between annular collar 112 and outer sleeve 110 is greater than the friction force between outer sleeve 110 and inner sleeve 108, outer sleeve 110 and inner sleeve 108 move relative to each other with a proximal movement of annular collar 112. Anchor 126 collapses to the retracted position as shown in FIG. 3, thus permitting the withdrawal of cannula assembly 100 from the patient.
To summarize, the user holds proximal portion 120 in one hand and annular collar 112 in the other hand and applies a force separating the two. This action moves portion 134 of outer sleeve 110 and inner sleeve 108 relative to one another, and therefore deploys anchor 126. As annular collar 112 and the movable portion of outer sleeve 110 continue to move toward distal end 104, anchor 126 becomes fully deployed. Thereafter, annular collar 112 begins to move relative to outer sleeve 110 and cinches-up against the skin. The friction fit force between annular collar 112 and outer sleeve 110 is preferably sized such that the force needed to overcome the friction fit force to move annular collar 112 relative to outer sleeve 110 is within the safe limits to prevent over insertion of cannula assembly 100 into the abdominal cavity.
Cannula assembly 100 may be used in surgeries other than laproscopic surgery. Additionally, it will be appreciated that other forms of anchors may be used with the cannula of the present invention and still remain within the broad scope of the present invention.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

## Claims

1. A method for anchoring and sealing a cannula assembly to the body of a patient, the method comprising the steps of: providing the cannula assembly having a proximal end; a distal end, and a longitudinal axis passing through the proximal and distal ends, the cannula assembly having an inner sleeve having an interior surface forming a passage through the cannula assembly and the inner sleeve having an exterior surface, the cannula assembly having an outer sleeve having an interior surface adapted for slidable engagement with the exterior surface of the inner sleeve, the cannula assembly having a radially expandable anchor toward the distal end of the cannula assembly, the radially expandable anchor being configured to be movable between a retracted position and an expanded position, and the cannula assembly having a longitudinally movable collar having an internal surface forming a friction fit with the exterior surface of the outer sleeve, a force sufficient to overcome the friction fit being greater than a force to move the radially expandable anchor from the retracted position to the expanded position; inserting the cannula assembly to a depth to place the radially expandable anchor in a retracted position within the patient; expanding the radially expandable anchor from the retracted position to the expanded position by moving the collar and the outer sleeve together toward the distal end of the cannula assembly, movement of the collar and the cuter sleeve as a unit providing the force to move the radially expandable anchor from the retracted position to the expanded position without overcoming the friction fit between the internal surface of the collar and the exterior surface of the outer sleeve; and sliding the collar toward the distal end of the cannula assembly after the expanding of the radially expandable anchor from the retracted position to the expanded position with sufficient force to overcome the friction fit.

2. The method of claim 1, further comprising forming a seal against an exterior surface of a patient after the radially expandable anchor is expanded.

3. The method of claim 1, further comprising locking the collar against an exterior surface of a patient after the radially expandable anchor is expanded.

4. The method of claim 1, further comprising moving the collar toward the proximal end of the cannula assembly to retract the radially expandable anchor and remove the cannula assembly from the patient.

5. The method of claim 1, wherein the sliding of the collar toward the distal end of the cannula assembly after the expanding of the radially expandable anchor from the retracted position to the expanded position continues until contacting the patient.

6. The method of claim 5, further comprising sealing an opening into the patient between the collar on an outside portion of the patient and the radially expandable anchor on an inside portion of the patient.

7. The method of claim 1, wherein the providing the cannula assembly includes the inner sleeve and outer sleeve being joined to one another proximate the distal end of the cannula assembly.

8. The method of claim 1, further comprising holding the proximal end of the cannula assembly during the expanding of the radially expandable anchor.

9. The method of claim 1, wherein the providing of the cannula assembly includes the radially expandable anchor being a distal portion of the outer sleeve.

10. The method of claim 1, wherein the providing of the cannula assembly includes the longitudinally movable collar being a single piece collar configured for axial movement along the longitudinal axis to without rotation expand the radially expandable anchor and seal an opening into the patient on an outside portion of the patient.

11. The method of claim 1, wherein both the expanding of the radially expandable anchor and the sliding of the collar toward the distal end of the cannula assembly occurs in one continuous motion to expand the radially expandable anchor and seal an opening into the patient between the collar on an outside portion of the patient and the radially expandable anchor on an inside portion of the patient.