WO2001089398A1

WO2001089398A1 - Reliable surgical access cannula system and related methods

Info

Publication number: WO2001089398A1
Application number: PCT/US2001/011345
Authority: WO
Inventors: David Kane; Steven Kane
Original assignee: Mount Olympus Devices Llc
Priority date: 2000-05-23
Filing date: 2001-04-06
Publication date: 2001-11-29
Also published as: AU2001253229A1

Abstract

Position-reliable cannulizing assemblies (50, 50'), and related methods, for accessing to desired internal location of a medical patient are disclosed. The cannulizing assemblies comprise deployable barbs (140) for retaining cannulas in a desired indwelling location.

Description

RELIABLE SURGICAL ACCESS CANNULA SYSTEM AND RELATED METHODS

Technical Field

The present invention relates generally to providing an access passageway irϊfo an

anatomical cavity of a medical patient and, more particularly, to novel cannulating assemblies, each of which is reliably retained with a distal end portion disposed in a desired body cavity, and

reliable related methods, by which one or more medical instruments are selectively and directly

inserted into the desired body cavity, through a passageway in the cannula system, for diagnostic, treatment or surgical purposes.

Background Art

Surgical, treatment and diagnostic cannula instruments are a commonly introduced into an anatomical cavity or space for diagnostic and operative procedures through a cannula. Ideally, cannula access is first gained and then maintained. Use of the indwelling cannula instrument may entail the repeated passage of treatment, surgical or diagnostic instruments into the anatomic

space of a medical patient or cavity through the cannula instrument. Insertion of cannula

instruments generally employs the usage of a sharp central piercing tool, generally known as a

trocar, which allows penetration of the tissue barriers surrounding the anatomic space, which may

be an encapsulated joint. After the anatomic space has been accessed, one or more cannula is retained indwelling and the trocar is withdrawn. This then establishes a temporary pathway wherein arthroscopic or endoscopic fiberoptic cameras or instruments, for example, may be

placed within the joint or anatomical space without further need of trauma to the surrounding

tissue. Such arthroscopic and endoscopic instruments are presently used most commonly in the

practice of diagnostic treatment and/or surgical procedures. Likely an increased need for better

access to body spaces through one or more cannulas will be needed in the future. While many cannula or sheath systems have been employed, for example, in the practice

of arthroscopic or endoscopic surgical intervention, a simple yet difficult problem has remained. Specifically, such prior art cannulas typically possess a tendency to back out of the anatomic space inadvertently once entry has been obtained and the operation or procedure is underway. With repeated influx and outflow of fluid, as is typical, and introduction and removal of

instrumentation from the space in question, the cannula or sheath tends to back or migrate out

with the movement of the instrumentation of local soft tissue. This forces discontinuance of the procedure and reinsertion of the trocar assembly from exterior to interior. Another trocar-carried cannula system is then inserted from the exterior to the interior of the anatomic space. This then causes further trauma to the patient, increases the risk of injury to both neurological and vascular parts of the body, and often results in two access tracks being established. The fact that a second access track may have been established creates a potentially serious problem for the maintenance

of fluid pressure within the joint or anatomic space, which is used to distend the space or anatomic cavity to allow better visibility during the procedure. With a second hole in the joint capsule or anatomic space membrane, fluids infused into the space tend to leak out of the now non-cannulated first access track and infiltrate the local soft tissue planes with unwanted fluid. This increase in local soft tissue fluid pressure can result in serious injury to muscles, nerves and

vessels in the affected area.

Some of the specific prior art access cannula approaches are discussed below in some

detail. Simple Cannula and Ribbed Cannula

An access cannula can be relatively simple and act simply as a portal as evidenced by

U.S. patents 4,655,752, 5,653,718 and 6,036,711. A basic problem with a simple cannula lies

in it's potential for inadvertent or migratory withdrawal from the anatomic space, necessitating

reinsertion which is time consuming and increases the risk for bleeding and other surgical or procedural complications. Thus methods have been proposed which help to ensure that the cannula remains within the anatomic cavity. The most simple method utilizes non-smooth or

ribbed surfaces on exterior of the cannula, which provide a frictional barrier to forward and

backward cannula movement. See U.S. patent 4,655,752, for example. The problem with such

designs is three-fold. First, the cannula still can undesirably be withdrawn from the anatomic

cavity. Second, tissue at the entrance or tissue wall of the anatomic cavity, has a propensity to

drape-over or cover the distal cannula opening if the cannula is placed at or close to the surface wall of the anatomic cavity. Usually this is a problem concerning the cannula withdrawing or

coming out of the cavity prior to completion of the procedure. Third, when one wants to move

the cannula deeper into the patient, to access other areas of the space, the ribs or non-smooth

surface of the cannula tend to make this maneuver more difficult.

Expandable Balloon Cannula

Other techniques to maintain a medical or surgical cannula within an anatomic space include an expandable balloon found at the terminal end of the cannula. Examples of such are

found in U.S. patents 5,176,697, 5,002,557, 4,496,345 and 5,919,163. While functional, this concept creates several problems having to do with surgical procedures. First, an inflatable balloon or membrane can be easily ruptured and is prone to such when sharp instruments are used in conjunction therewith, which is commonplace in the field of surgical practice. Secondly,

air or fluid leaks are inherent to such devices and create another source of device failure. Thirdly

and perhaps more critically, is the rounded nature of such balloon-like structures. As the inner wall of an anatomic cavity is very slippery and pliable, the ability of a rounded structure, like a small balloon, to maintain retraction on the anatomic wall without pulling through the opening,

makes this inflatable balloon construct effective only if the balloon is of a relatively large size.

Increasing the size of an inflatable balloon, to keep it well anchored within an anatomic space, would decrease the area visualized and accessible to the surgeon. This precludes its usage in many areas of the body such as the wrist, ankle and pediatric joints of all kinds, as it simply takes

up to much space. Fourth, most inflatable balloons are circumferential at the distal end of the cannula and restrict the amount of the toggling available at the cannula to access all areas of the anatomic space or joint cavity, which are not directly in front of the entrance point of the joint or space. In other words, having a ring of balloon all the way around the distal cannula, makes movement of the cannula, side-to-side, in order to view other areas of the joint or body cavity, more difficult.

End Cannula Deployed Curved Wires or Loops

A third technique to secure the cannula within the anatomical space entails the introduction of pliable or curved retention members that exit the distal end of the cannula once the cannula has been placed within the body cavity or joint. This can be seen in U.S. patents 5,279,564 and 5,713,870. While generally functional in holding the distal cannula within the body cavity, this concept has an inherent weakness in its rounded retaining members as they meet the anatomic wall. As in the case of the expandable balloon cannulas, the curved nature of these cannula retention devices makes questionable their ability to firmly hold the anatomical wall membrane. Secondly, these devices employ the usage of wire-like retention arms that are prone to pull through the wall membranes. Another weakness lies in that any retention wire or device that travels within the lumen of the cannula, has the distinct possibility of interfering with surgical instrument passage down the cannula. See U.S. patent 5,713,870. Perhaps more importantly, as in the case of U.S. patent 5,279,564, when the retention arms are fully deployed and most effective in anchoring the cannula, the tip of the cannula is by necessity, quite far advanced into the joint or body cavity (see U.S. patent 5,279,564). Ideally, one would have the anchoring device functional at the very most distal part of the cannula so as to be able to withdraw the cannula right up to, but not beyond the anatomical wall. In so doing the surgeon has the maximum amount of space available for surgical manipulation or visualization within

the joint or space. This is critical in many cases because the amount of free space available

within a joint is minimal and any space occupied unnecessarily by the distal end of the cannula,

inhibits or prevents the surgeon from completing the procedure.

Mushroom or Accordion Anchoring

Another method of anchoring the cannula in the capsule of the joint involves a

mushrooming or accordion technique for which there are a multitude of pertinent U.S. patents,

i.e., 5,387,196, 5,330,497, 5,290,249, 5,232,451, 5,203,773, 5,836,913, 5,882,340, 5,707,362, 5,637,097 and 5,888,196. The devices of these patents function on the same principle of a mushrooming or accordion type device that, when deployed, expand in an outwardly radial

direction. While functional, these types of devices all have the inherent problem of a relatively rounded or smooth interface with the joint or anatomic space membrane and make the device prone to inadvertent withdrawal from the cavity. This is the same problem that was discussed in the evaluation of the inflatable balloon devices. Furthermore, to deploy the accordion or mushroom, the entire length of the accordion wings must be within the anatomic space or joint

prior to deployment. In a smaller joint, there will likely be inadequate room to allow the

accordion or mushroom wings to be placed within the joint prior to deployment. As with pliable

retention members discussed above, another inherent weakness of the mushroom or acόordion

design lies in the fact that in its deployed state, the wings lie proximal to the cannula tip by varying amounts. This, as previously discussed, takes up critical amounts of space in smaller cavities and joints. See U.S. patents 5,637,097, 5,707,362, 5,836,913, 5,882,340, 5,330,497

and 5,290,249. Additionally, each deployment flange within the mushroom or accordion concept

entails three or more bending actions that must bend and unbend with deployment and undeployment. As with any mechanical device, areas of bending built into a plastic component,

are prone to failure and three with each flange, increase the risk three fold. See U.S. patent

5,707,362 where no less than 21 such bends or plastic joints are depicted at the distal end of the

cannula.

Forward or Loop Deployed Anchoring Flanges

U.S. patents 5,707,359 and 5,971,960 use forward deployment of flanges which are

hinged on the distal end of the cannula. Additionally, U.S. patent 5,971,960 discusses a

rotational set of distal wings that deploy through the rotation of an inner cannula in respect to an

outer cannula. First the usage of forward deployed wings has the inherent problem of easy backward withdrawal of the cannula secondary to the mechanical disadvantage that the anchoring members experience with pulling on the cannula. In backward pulling on the cannula, the wings would tend to collapse and allow the cannula to be inadvertently withdrawn from the joint or anatomic space. This is apparent when one critically evaluates the prior art. Additionally, U.S. patent 5,971,960 is a very complicated device, with a multitude of movable parts, and is both

difficult and expensive to manufacture and assemble. U.S. patent 5,971,960 also describes a rotationally deployed set of "loop" flanges. This idea is limited in its function by the circumference of the cannula. At the smaller cannula diameters which are common in the practice of arthroscopic surgery (typically 7-8 mm), the amount of outward projecting loop

flange is very small and is not adequate to resist backward tension on the cannula. To assure any

meaningful amount of outward "loop" flange deployment, one must involve nearly the entire

circumference of the distal cannula which makes the distal end of the cannula mechanically weak and prone to failure. (See figs. 10 and 11 of U.S. patent 5,071,960). Disclosure of the Invention

In summary, the present invention solves or significantly alleviates problems of the prior

art as these problems relate to reliable cannulation of body cavities of and encapsulated regions

within medical patients to accommodate reliable introduction, use and retraction of diagnostic, treating and surgical instruments. Arthroscopic and endoscopic instruments are two of many

instruments which may use cannulation of a desired body site to accommodate introduction, use

and withdrawal on a low invasive basis.

It is a primary object of the present invention to solve or significantly alleviate problems

of the prior art related to reliable cannulation of body cavities of and encapsulated regions within

medical patients to accommodate reliable introduction, use and retraction of diagnostic, treating and surgical instruments.

It is another dominant obj ect to provide novel assemblies and related methods for reliably cannulating body cavities and encapsulated regions, including but not limited to joints, within the bodies of humans and animals to insure reliable introduction, use and withdrawal of diagnostic, treating and surgical instruments through the cannula.

A further valuable object of the present invention is to provide novel cannulating assemblies, and related methods, which assemblies possess or achieve at least one if not more of the following novel features: (1) provision of deflectable cannula-retaining stops which fail- safingly retain the cannula in a body cavity, which avoids or alleviates anatomical damage; (2)

provision of stop tabs near the distal end of cannulating assemblies which are biased away from

the distal end; (3) provision of spaced planar stops near the distal end of cannulating assemblies

which extend in a proximal direction no more than an immaterial or insignificant extent; (4) provision of position stabilizing stops near the distal end of cannulating assemblies which avoid cannula slippage or displacement due to non-curved engagement between anatomical surfaces

and stop surfaces; (5) provision of cannulating assemblies with deployable distal stops which are not inflatable; (6) provision of cannulating assemblies having no external obstruction and which

are not enlarged or bulky during insertion into a body cavity or encapsulated region; (7) provision

of cannulating assemblies which accommodate reliable anchoring or retaining of the cannula to

the body after insertion into a body cavity or encapsulated region; (8) provision of cannulating

assemblies which are not highly invasive of body cavities and encapsulating regions and do not

deprive the physician or surgeon of space needed within the cavity or region; (9) provision of

unique techniques for deployment of cannula-retaining stops within a body cavity or encapsulating region; (10) results in low manufacturing costs; (11) provision of cannulating

assemblies having deployable position-retaining stops possessed of no more than one hinge for

correctly positioning the stops when deployed; (12) provision of low trauma, easily withdrawn and easily relocated cannulating assemblies; (13) provision of highly reliable and medically

predictable cannulating assemblies; (14) provision of small diameter, thin wall cannulating assemblies; (15) provision of cannulating assemblies with yieldable stops with free ends which are deployed so as to not extend beyond the distal-most part of the assemblies, or which are deployed laterally through rotation of a cannula member or which are deployed in a proximal direction by proximal displacement of one cannula member in respect to another cannula member.

These and other objects and features of the present invention will be apparent from the

detailed description taken with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 is a perspective of one cannulizing assembly embodying principles of the present invention;

Figure 2 is a side elevation of the trocar, which forms a portion of the assembly of Figure

i; Figure 3 is a fragmentary cross section of a piercing element, in the nature of a hollow

needle, which may be used as part of the assembly of Figure 1 in lieu of the trocar shown best

in Figure 2;

Figure 4 is a perspective representation of a partible or severable sheath forming a part

of a guidewire/partable sheath assembly by which the cannulizing assembly of Figure 1 or one like it may be introduced into the body of a medical patient to accommodate treatment, diagnostic

activity or surgery;

Figure 5 is an enlarged cross sectional view taken along lines 5-5 of Figure 1, except

position-retaining detent elements have been added and two position retaining barbs are shown;

Figures 6 and 7 are enlarged fragmentary cross sectional views of the distal end of the

assembly of Figure 1, showing the stop barbs in their non-deployed and deployed positions, respectively;

Figure 8 is an enlarged fragmentary perspective of a further embodiment of the present invention showing alternative detent elements for position- retaining purposes.

Figures 9 and 10 are enlarged fragmentary perspectives, with a portion broken away to provide clarity, illustrating the detent elements of Figure 5 in their advanced and retracted positions, respectively;

Figure 11 is a fragmentary, somewhat schematic cross section showing the assembly of Figure 1 inserted into an encapsulated region of a medical patient, i.e. at a shoulder joint;

Figure 12 is an enlarged fragmentary cross section of a distal end of a further cannulizing

assembly embodiment according to the present invention where stop barb deployment is in

essentially a transverse or radial direction, but is implemented by displacing the inner cannula in a proximal direction relative to the outer cannula;

Figure 13 is a fragmentary enlarged cross section, similar to Figure 12, showing the stop barb as being joined to the inner cannula at a living hinge, to aid in deployment; Figure 14 is an enlarged fragmentary cross section showing another cannulizing assembly

embodiment of the present invention comprised of barbs which are curved when deployed;

Figure 15 is an enlarged fragmentary cross section illustrating forward or distal deployment of at least one barb so that the barb extends essentially transversely or radially and

where the flexure of the barb is accommodated by a living hinge;

Figure 16 is an enlarged fragmentary cross section similar to Figure 15 showing a

transversely deployed barb without a living hinge;

Figure 17 is an enlarged fragmentary prospective of a further barb embodiment according

to the present invention;

Figure 18 is an enlarged fragmentary perspective of an additional barb embodiment of

the present invention;

Figure 19 is one more barb embodiment in accordance with the present invention

showing four barbs, which are cantilever from the interior cannula, are flexible or deflectable, have free ends and extend generally transverse out ports or openings in the outer cannula, when deployed, where the barbs do not extend beyond the distal end of the assembly;

Figure 20 is a fragmentary perspective illustrating another tapered barb embodiment of the present invention;

Figures 21 through 26 illustrate some of the many cross sectional shapes which may be utilized in forming barbs in accordance with the principles of the present invention;

Figure 27 is an elevational view of a cannulizing assembly in accordance with the present invention indwelling within a body cavity or the like of a patient, equipped with an external

cushioning device to prevent play in a cannulizing assembly while it is indwelling;

Figure 28 illustrates detent elements in enlarged fragmentary elevation which may be used to retain deployed and non-deployed position of one or more barbs, when rotational deployment is used; Figure 29 is an enlarged cross sectional view taken along line 29-29 of Figure 28;

Figure 30 is a side elevation with parts broken away showing a key/keyway system by

which relative rotation between the inner and outer cannulas is prevented; and

Figures 31 and 32 are fragmentary perspectives of rotationally displaceable barbs in their

non-deployed and deployed positions, respectively.

Best Mock for Carrying Out the Invention

Reference is now made, in particular, to the drawings wherein like numerals are used to

designate like parts throughout. In reference to Figure 1, a cannulizing assembly, generally

designated 50, is illustrated in perspective. The assembly 50 comprises a central piercing element, illustrated as being a trocar, generally designated 52, which is of conventional configuration, an outer cannula, generally designated 54, and having a finger control handle, generally designated 56, integral with the proximal end of the outer cannula 54, and an inner, barb-carrying cannula, generally designated 58, which is integral with and terminates in a proximal hub, generally designated 60. The hub 60 may be used in conjunction with a seal

mechanism or seal assembly, generally designated 62.

The trocar 52 is representative of only one of several available piercing elements which

can be utilized in conjunction with cannulizing assemblies in accordance with the present

invention to provide penetration into a desired internal location within the body of a medical

patient, such as a body cavity or an encapuslated region, such as an orthopedic joint. Piercing element trocar 52 is illustrated, in Figure 2, as comprising an elongated rod 64 illustrated as being

solid and of uniform diameter throughout. The length of the rod 54 is selected to correspond to

the distance required to be penetrated by the cannulizing assembly 50 to reach the desired body

location. The rod 64 terminates in a cone-shaped sharp piercing tip 66 at the distal end of the trocar 52 and a manual handle 68 at the proximal end of the rod 64. A stop 70, integral with the knob-shaped handle 68 is provided for contiguous disposition against the assembly 50 when in the assembled position of Figure 1. Both the handle 68 and the stop 70 have diameters

significantly greater than the diameter of the rod 64, with the stop 70 comprising a radially-

directed flat distal surface 72, which is disposed contiguous with the seal assembly 62, when the

cannulizing assembly 50 is operationally assembled as illustrated in Figure 1.

The trocar 74 may be formed as one piece of stainless steel or a suitable shape-retaining material comprised of medical grade synthetic resinous material, appropriate for the purpose

intended. In lieu of the piercing element 52 of Figure 2, a hollow needle, generally designated

74 in Figure 3, may be used. The hollow needle 74 may be exchanged for the trocar 52 in the

assembly of Figure 1, for purposes of piercing the body of the patient to the site desired for medical treatment, surgery or diagnostic endeavor. The hollow interior 76 of the needle 74 may be plugged or closed in any available manner as may be appropriate for the procedure in question, as would be apparent to those skilled in the art. The needle 74 is illustrated as

comprising a distal sharpened tip 78, for ease of body entry.

Reference is now made to Figure 4 which illustrates an additional way in which delivery of the distal end of the assembly 50 of Figure 1 may be achieved to the desired body location of a medical patient. Specifically, those of skill in the art are familiar with the commercially available guidewire, splittable sheath technology by which a tube or tubular instrument may be suitably introduced into the body of a medical patient. Typically, the exterior of the body is

penetrated by a suitable sharpened element. By using known guidewire techniques, the partable

sheath 80 (Figure 4) is introduced from the exterior of the patient into the region of body penetration. The distal end of the assembly 50 is then introduced through the hollow interior 82 of the partable sheath 80 and the sheath is manually separated along opposed grooves 84 until

the upper and lower halves 86 and 88 are separate pieces. These pieces are discarded, leaving the tip or distal end of the dual cannulas of the assembly 50 suitably disposed within the patient. If desired, the guidewire, partable sheath approach described above in conjunction with Figure 4, may be used in conjunction with the complete assembly 50 including the trocar 52, where

further internal penetration is needed.

It is to be appreciated that the assembly 50 in Figure 1 is comprised of outside and inside

cannulas 54 and 58, where the cylindrical walls of each are of uniform outside diameter, uniform

inside diameter and uniform thickness throughout their entire lengths. The cannulizing assembly

50', shown in Figure 5, is identical to assembly 50 of Figure 1, with the exceptions of certain

detent elements, which will be explained in greater detail later. Otherwise, assembly 50' and

assembly 50 are illustrated as being identical. Figure 5 does not, however, illustrate the above-

explained trocar or any other piercing element.

The outside cannula 54' of the assembly 50' illustrated in Figure 5 is formed of a tube 90

illustrated as having a uniform thickness. With the exception of annular ridges 92 and 94, the tube 90 has an outside annular or cylindrical surface 96 of uniform diameter and an inside annular or cylindrical surface 98 of uniform diameter. Outside cannula 54' may be formed of any suitable material, preferably a shape-retaining synthetic resinous material of medical grade. The distal end 100 of the outside cannula 54' is interrupted by at least one radially-disposed aperture (opening or fenestration) 102, for purposes yet to be explained.

As mentioned earlier, the uniform diametral nature of the outside cannula 54 (Figure 1)

remains the same along its entire length, whereas the outside cannula 54' is interrupted by two radially-disposed or annular ridges 92 and 94, which are illustrated as being dome-shaped in

cross section. Thus, the ridges 92 and 94 are convex when viewed from the outside and concave when viewed from the inside. The ridges 92 and 94 constitute detent elements for position- retention purposes, as explained later in greater detail.

The distal end 100 of the outside cannula 54' is illustrated as comprising a blunt, radially-

directed edge 104. If desired, forpurposes of ease of entry or some other purpose, the distal edge 104 at distal end 100 may be beveled, round, tapered or otherwise shaped, as desired or determined to be appropriate by those skilled in the art.

The proximal end 106 of the outside cannula 54' terminates in a proximal edge 108,

shown to be blunt or radially-disposed. The outside surface 96 of the outside cannula 54' is

contiguous with the handle 56 forming an interface 110 therewith. Glue, adhesive or welding

at interface 110 may be utilized to integrally connect the proximal end 106 of the outside cannula 54' to the handle 56 so that the two may be manually displaced together. The handle 56 is

illustrated as having been formed as one piece so as to comprise a central boss 112 and a pair of

oppositely-directed finger controls 114 by which the handle 56 and the outside cannula 54' (or

54 as the case may be) may be unitarily advanced in a distal direction or retracted in a proximal direction relative to the inside cannula 58' (or 58) for purposes yet to be set forth.

When and to the extent advisable it is desired to prevent relative rotation of the outside cannula relative to the inside cannula, a key/keyway or other anti-rotational mechanism may be

provided. Any suitable anti-rotation mechanism may be used, including the one illustrated in Figure 30. Specifically, the key keyway arrangement, generally designated 130 in Figure 30, illustrates one of the handles or finger controls 114 as comprising a rectangularly-shaped recess 132, which functions as the keyway. The arrangement 130 further comprises a fin, rib or flange 134, made as one piece or integrally connected to the outside surface of the inside cannula 58'

(or 58 as the case may be). The fin 134 functions as the key and is sized and shaped so as to accommodate placement in the groove 132 and relative axial sliding of the outer and inner cannulas, while preventing relative rotation one cannula in respect to the other cannula.

The inside cannula 58' comprises a tube 136 which, with the exception of an annular detent element 138 and stop barb or barbs 140, comprises an outside annular or cylindrical

surface 142 of uniform diameter and an inside cylindrical or annular surface 144 of uniform diameter. Therefore, the thickness of the tube 136 is essentially uniform, as illustrated in Figure 5 and elsewhere. The distal end 146 of the inside cannula 58' terminates in a blunt edge 148. Edge 148 may, however, be tapered, beveled, rounded or otherwise configured, as may be appropriate to those of skill in the art. The distal end 146 is also die-stamped or otherwise cut to form at least one U-shaped slit 150, two such slits 150 being illustrated in Figure 5. Once the U-shaped cut 150 is made, a cantilevered tongue is formed at each cut 150, each tongue being pre-biased, bent or bendable and attached to the inside cannula at a hinge or pivot site 152. The tongue so cut comprises the stop barb 140, which connects at site 152 to the tube 136. Each stop barb 140 comprises a free end which is beveled at edge 154. Thus, upon engagement of a ramp edge 156 of the outside cannula, as the inside cannula 58' is relatively retracted, the barb 140 will deflect generally radially outwardly from a collapsed position (illustrated in Figure 6) to an extended operative position (illustrated in Figure 7). The barbs 140, when extended after body placement, prevent inadvertent withdrawal of the cannulas from the body site into which the distal ends thereof have been inserted. Thus, in the configuration illustrated in Figure 7, each barb 140 does not extend at all in a distal direction but is radially flared so that it extends beyond the diametral size of the outside cannula both radially and proximally, making it essentially impossible for the cannulas to be removed from the desired body site on an unintended, inadvertent basis.

As mentioned earlier, the annular rib 138 of the inside cannula constitutes a detent element which may be manually placed in nesting relation with either the detent element 94 or the detent element 92 of the outside cannula, as and when it is desired to extend or collapse the barb or barbs 140. Note in the collapsed position, each barb 140 comprises a diametral size no greater than the diameter of the outside surface 96 of the tube 90. Thus, each barb 140 presents no obstruction during insertion and removal, when each barb 140 is collapsed, as illustrated in Figure 6.

The tube 136 comprises a proximal end region 160, illustrated in Figure 5 as terminating in a blunt proximal edge 162. The hub 60 is superimposed contiguously upon the outside surface 142 of the tube 136 at interface 164. Adhesive, bonding agent or plastic welding may be used

to make tube 136 and hub 60 integral and thus non-rotatably secure the hub 60 to the distal end

160 so that the two move together when displacement occurs.

The hub 60 comprises a cylindrical boss 166 (Figure 5), which is interrupted at one

location by an integral stem 168, which has a hollow passageway 170 disposed therein. The stem

168 is formed as one piece with the hub 60 and comprises an enlarged head 172, which, during

storage, may be closed by use of a press-fit plastic cap 174 (Figure 1). An aperture 174 is disposed in the tube 136 in alignment with the passage 170 to accommodate liquid flow for

flushing purposes, for example. A supply tube (not shown) may be force-fit over the head 172, with the cap 174 removed, during use through which a suitable flushing liquid may be

dispensed, which in turn reaches the selected body site through passage 170, aperture 174 and

the hollow interior of the tube 136. See Figure 5.

The hub 60 comprises an annular proximal portion 176 having an inside smooth cylindrical surface 178, the diameter of which is greater than the diameter at the interface 164. Thus, a shoulder 180 of annular configuration exists between surface 178 and interface 164.

Proximal portion 176 comprises an exterior threaded surface 182 and a blunt proximal edge 184. Edge 184 is interrupted by a pair of oppositely-located blind bores 186.

The seal assembly 62 of Figure 1, illustrated in greater detail in Figure 5, comprises an

exterior threaded cap 188, which is formed as one piece and comprises a radially-directed proximal wall 190 centrally apertured at 192 for piercing element access. Wall 190 joins a

longitudinally-directed sleeve 194 at outside corner 196. Sleeve 196 internally comprises a

smooth annular proximal surface 198 and a distal threaded surface 200. The threads 200 are sized and shaped so as to match and threadedly engage the threads 182 of the proximal portion 176 of the hub 60. Interiorly interposed between the inside surface of radial wall 190 and the blunt proximal edge 184 of the hub 60 are three washer-like elements, i.e., a rigid retaining ring 202, a discshaped diaphragm 204, having a central aperture 206 disposed therein, and slit valve diaphragm 208 having a central, normally closed slit 210 therein. Diaphragm 208 may be made of silicon rubber to insure re-sealability. Slit 210 accommodates introduction and removal of the trocar 52 or other piercing element so as to preserve a seal against the piercing element, when present, and a seal against itself when there is no piercing element present. The retainer ring 202 comprises distally-directed male pegs 212, which extend through apertures in the diaphragms 204 and 208 and into the blind bores 186, to create and retain non-rotatable fixed relationships between the retaining ring 202 and the diaphragms 204 and 208.

Thus, when the cap 188 is threaded onto the hub 60 at threads 182 and 200, and thereafter tightened, the retaining ring 202 and the diaphragms 204 and 208 are held compressively as depicted in Figure 5. Nevertheless, by loosening the cap 188, the seal assembly 62 may be readily removed and disassembled, when and if such is desirable.

It is to be understood that the exact physical nature and deployment of position-retaining stop barbs in accordance with the present invention may vary. The cross sectional configuration is not limited to any particular shape. Any suitable cross sectional shape, such as those illustrated in Figures 21 through 26, may be utilized. The tip of any given stop barb may be blunt, tapered or beveled, pointed or flat, without departing from the essence of the present invention. The cross sectional configuration of stop barbs within the scope of the present invention may be uniform from the cantilevered connection to the inside cannula to the tip thereof or the cross sectional configuration may vary between the cantilevered connection and the tip. See, for example, the converging top and bottom surfaces of the stop barb 140 shown in Figure 20 and the side taper of the barb 140 shown in Figure 18. Furthermore, the stop barbs of the present invention may be deployed in essentially an

end-to-end linear configuration, as illustrated in Figures 7, 12, 13, 15 and 16 or in a curvilinear

orientation as shown in Figure 14. Deployment is substantially radial, although the tips of the

stop barbs may be directed in a proximal direction or in a generally radial direction. Some

extension in a distal direction may also be accommodated, particularly when the barbs are

yieldable, but the barbs should not be dominantly distally directed nor should the barbs extend

beyond the distal end of the cannulizing assembly.

The barbs may be somewhat stiff or sufficiently flexible to accommodate anatomical

deflection when forcible contact occurs with a somewhat rigid portion of the patient's anatomy.

In this way, internal injury or damage is avoided while the inserted position of the cannulizing

assembly is maintained.

In some embodiments it may and likely will be of value to utilize a reduced thickness living hinge at or near the point of cantilever connection between the barb 140 and the inside cannula. See the living hinges 210 in Figures 13 and 15.

While in most embodiments of the present invention, retrograde deployment, i.e., deployment by displacing the inside cannula in a proximal direction relative to the outside cannula, is preferred, other forms of deployment of the barbs, including as relative advancement of the inside cannula in a distal direction and rotational deployment, are within the scope of the

present invention. Retrograde deployment is illustrated in Figures 6, 7, 12, 13, 14, 17, 18, 19, and 20. Distal deployment is illustrated in Figures 15 and 16 and rotational deployment is

illustrated in Figures 31 and 32. During rotational deployment, the inside cannula is rotationally displaced in respect to the outside cannula, causing circumferentially-disposed barbs 140' to move from a collapsed position, shown in Figure 31, to an extended position shown in Figure

32. The barbs 140' are illustrated as being pre-biased to curl somewhat when deployed, as shown in Figure 32. In this case, no key/keyway anti-rotational structure would be provided. The position-retaining or anti-inadvertent removal feature of barbs according to the

present invention is well understood by reference to Figure 11, which shows the cannulizing

assembly inserted into an encapsulated region 212 of a shoulder joint of the medical patient.

Note, the barbs 140 reliably engage the interior surface of muscle layer 214. The cannulizing

assembly is shown as having penetrated the skin 216, the layer of fat 218 and the muscle layer

214, the trocar or other piercing element having been removed and the barbs 140 having been

deployed into their radially-expanded, proximally- directed position-retaining orientation. This allows the physician to insert through the inside cannula a suitable commercially available

instrument for surgical, treatment and/or diagnostic purposes.

In instances where it is desirable to avoid displacement of the inserted cannulizing

assembly, including the deployed barbs 140, in an inward direction, a split resilient spacer 220 may be inserted immediately distal of the handle 56 such that the barbs 140 and the cushion 220 together cause the human tissue through which the inside and outside cannulas pass to be placed in compression thereby eliminating any play which might otherwise be available to the cannulas to move in an inward direction. Note, the donut shaped cushion 220 has a slit at 222 which may

be manually spread to insert the cushion over the outside cannula 54, 54' into the position illustrated in Figure 27. The cushion 220 also has a central aperture 224, the diametral size of which is slightly greater than the adjacent outside diameter of the outside cannula. The cushion or spacer 220 may be formed of any suitable compressible material, such as synthetic resinous

foam of medical grade quality.

In reference to Figures 5, 9 and 10, an axial or longitudinally-based detent mechanism

for retaining the barbs in deployed and non-deployed states will now be explained. As mentioned earlier, the outside cannula 54' is comprised of two annular outwardly extending ridges 92 and 94. The material from which the outside cannula 54' is made is shape-retaining, but capable of

some radial deflection for purposes yet to explained. The inside cannula 58' is formed of similar synthetic resinous material which is shape-retaining although capable of being inwardly deflected

to some extent for purposes set forth below.

The inside cannula 58' comprises a single radially-directed ridge 138, which is sized and

shaped so as to fit contiguously and snugly within the internal convex portion of either ridge 92 or 94. Relative axial manual movement in a proximal direction will cause the ridge 138 to leave

the internal convexity of ridge 92, move compressibly along the inside surface 98 of the tube 90,

expanding slightly the diameter thereof, while somewhat compressing the ridge 138 until ridge

138 seats or nests into the internal convexity of the ridge 94. This also deploys the associated

barb or barbs 140 from a collapsed to an extended position, as illustrated in Figures 5 and 7, for example. This is done while the distal end of the cannulizing assembly is suitably disposed within a body cavity or encapsulated region of a medical patient.

When the cannulizing assembly has served its intended purposes (by providing access for a diagnostic, treating or surgical instrument) and it is desired to remove the cannulizing

assembly from the patient, the barbs 140 are returned to their collective position by advancing the inside cannula 58' in a distal direction relative to the outside cannula 54' causing the ridge 138 to leave the convexity of the ridge 94 and obtain a nested position within the convexity of the ridge 92.

In lieu of the detent elements illustrated and described in respect to Figures 5, 9 and 10,

any suitable alternative detent mechanism may be provided within the scope of the present invention by which barb deployed and non-deployed positions may be sustained against

inadvertent loss of those positions. One such alternative detent system is illustrated in Figure 8

wherein the handle 56 is equipped with a proximal teardrop-shaped male detent element 230 and the key/keyway mechanism, previously described in conjunction with Figure 30, is equipped with a raised exposed portion 232 which is longitudinally aligned with the male detent element 230.

The raised portion 232 comprises two female groove elements 234 and 236, which are spaced one from the other by a center-to-center distance equal to the distance required for moving the

barbs 140 from their collapsed to their fully deployed positions. The male detent element 230

is sized, shaped and located so that its distending surface rides up along ramp 238 and nests or

seats in groove 234 to obtain the collapsed, ready for body insertion position, where deployment

is in a proximal direction. Manual force of the type used seat the male detent element 230 in

groove 34 may also be used to override that position forcibly and seat the male detent element 230 in proximal groove 236, which places the associated barbs 140 in their deployed position,

such as that illustrated in Figure 7, when deployment is in a proximal direction.

However, when deployment is in a distal direction, placement of the male detent element

230 in female detent groove 236 would position the associated barb or barbs 140 in their

collapsed, insertable position, while placement in the female detent groove 234 would deploy the barbs. See Figures 15 and 16.

In situations where an anti-rotation feature is not included in cannulizing assembly according to the present invention and the barbs 140, 140' are rotationally disposed, deployed and retracted, in the manner illustrated, for example, in Figures 31 and 32, rotational detent elements may be employed. In this regard, reference is made to Figures 28 and 29 which illustrate outside cannula 54 " as comprising a pair of dome-shaped male detent elements 250 and 252 located just distal of the handle 56. The male detent elements 250 and 252 have a concave exterior surface

and a convex interior surface, as shown in Figure 29. The inside cannula 58 " comprises a male detent member 258, which can be caused to seat or nest in the interior convex portion of either

element 250 or 252. When the barbs 140' in Figures 31 and 32 are deployed by clockwise rotation of the inside cannula relative to the outside cannula (when viewed from the proximal end

of the assembly), the male detent element 254 is manually moved from a seated or nested relation with element 250 to a seated nesting relationship with element 252. When the element 254 is

nested in element 250, the barbs are retracted. When the element 254 is nested or is seated in the element 252, the barbs are rotationally deployed, as illustrated, for example, in Figure 32.

However, the barbs 140' of Figures 31 and 32 could be oriented oppositely, in which case

deployment would be as a result of counterclockwise rotation of the inside cannula relative to

the outside cannula, when viewed from the proximal end of the assembly. In this case, when

element 254 is nested with element 252, such oppositely directed barbs would be retracted and

when nested in element 52, the oppositely directed barbs would be deployed.

The invention may be embodied in other specific forms without departing from the spirit of the central characteristics thereof. The present embodiments therefore to be considered in all

respects as illustrative and not restrictive, the scope of the invention being indicated by the

appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

Claims

1. A cannulizing assembly for accessing to a desired internal site of a medical patient

comprising:

outside and inside relatively movable cannula, each cannula comprising a hollow interior

and a distal end;

the distal end of the inside cannula comprising at least one radially-deployable

anatomically retaining barb;

the distal end of the outside cannula comprising at least one radially-disposed opening; the assembly accommodating relative movement of the inside and outside cannula between a non-deployed collapsed position and a deployed position where the barb radially projects through and beyond the opening beyond the outside cannula.

2. A cannulizing assembly according to Claim 1 wherein the at least one barb comprises at least two barbs and the at least one opening comprises at least two openings accommodating deployment of the at least two barbs through the openings.

3. A cannulizing assembly according to Claim 1 wherein the at least one barb is cantilevered from the inside cannula.

4. A cannulizing assembly according to Claim 1 wherein the at least one barb, when deployed, extends predominantly in a radial direction.

5. A cannulizing assembly according to Claim 1 wherein the at least one barb, when deployed, extends in both radial and proximal directions.

6. A cannulizing assembly according to Claim 1 further comprising structure preventing the at least one barb from extending in a distal direction beyond distal end of the

assembly, when deployed.

7. A cannulizing assembly according to Claim 1 further comprising a removable body-

piercing element disposed initially within the inside cannula.

8. A cannulizing assembly according to Claim 7 further comprising a proximal seal

through which the piercing element is displaced when inserted and removed from the assembly

and through which a diagnostic, treating and/or surgical instrument is displaced.

9. A cannulizing assembly according to Claim 7 wherein the piercing element is selected from the group comprising: a trocar, a needle and a guide wire mechanism.

10. A cannulizing assembly according to Claim 1 further comprising a proximal port for introducing a liquid into the patient through the hollow interior of the inside cannula.

11. A cannulizing assembly according to Claim 1 further comprising at least one barb-

engagement site carried by the outside cannula which causes the at least one barb to flare radially outward and rearward when the inside cannula is displaced rearward relative to the outside cannula.

12. A cannulizing assembly according to Claim 1 further comprising at least one

releasible locking mechanism disposed at an interface between the inside cannula and the outside

cannula which holds the inside cannula and the outside cannula in a barb-deployed position

against inadvertent displacement.

13. A cannulizing assembly according to Claim 1 comprising two releasible locking

sites which respectively hold the two cannulas in non-barb deployed and barb-deployed positions

against inadvertent displacement.

14. A cannulizing assembly according to Claim 13 wherein the two releasible locking

sites comprise male and female detents.

15. A cannulizing assembly according to Claim 1 further comprising structure which creates and preserves alignment between two cannulas.

16. A cannulizing assembly according to Claim 15 wherein the alignment structure comprises at least one key and at least one keyway which is sized and shaped to receive the key.

17. A cannulating assembly according to Claim 1 wherein each cannula comprises a tip

and the at least one barb and the at least one opening are immediately proximal of the tip so that

invasion of the internal site is minimal.

18. A cannulating assembly according to Claim 1 wherein the at least one barb comprises a pliant deflectable distal region.

19. A cannulating assembly according to Claim 1 wherein the at least one barb

comprises depth dimension which decreases from a proximal end to a distal end thereof.

20. A cannulating assembly according to Claim 1 wherein the at least one barb is

ribbon-shaped.

21. A cannulating assembly according to Claim 1 wherein the at least one barb is

convergingly tapered from a proximal location to a distal location.

22. A cannulating assembly according to Claim 1 wherein the at least one barb is

formed as one piece with the inside cannula.

23. A cannulating assembly according to Claim 1 wherein the diametral size of the outside cannula is equal to or greater than the diametral size of any other portion of the assembly which is inserted into the patient.

24. A cannulating assembly according to Claim 1 wherein the at least one barb is

formed as one piece with the inside cannula and further comprising a living hinge interposed

between the at least one barb and the inside cannula.

25. A cannulating assembly according to Claim 1 wherein the at least one barb is

substantially flat, is cantilever connected to the inside cannula and comprises a free yieldable distal end portion.

26. A cannulizing assembly for accessing to a desired internal site of a medical patient comprising:

a piercing element;

and a distal end, the piercing element being initially surrounded by the inside cannula;

the distal end of the inside cannula comprising at least one radially-deployable anatomically retaining barb; the distal end of the outside cannula comprising at least one radially-disposed opening;

the assembly accommodating relative movement of the inside and outside cannula

between a non-deployable collapsed position and a deployed position where the at least one barb radially projects through the opening beyond the outside cannula.

27. A method of cannulizing a desired site within the body of a medical patient comprising the acts of: providing a cannulizing assembly; piercing the body of the patient with the assembly until a distal end of the assembly is disposed at the desired site;

laterally deploying to an extended position at least one retention barb carried at the distal

end of an inside cannula of assembly from a collapsed position through an opening at the distal end in an outside cannula without the at least one barb extending in a distal direction beyond the distal end of the assembly;

securely retaining the inside and outside cannula at the site by physical engagement between the deployed barb and an anatomical location at the site.

28. A method according to Claim 27 further comprising the acts of: inserting and later removing a diagnostic, treating or surgical instrument into the site through the inside cannula, with the piercing element removed; thereafter, returning the at least one barb to its collapsed position and removing the assembly from the patient.