This application claims priority to U.S. Provisional Application 61/775,464 filed March 8, 2013.

Field of the Inventions The inventions described below relate to the field of arthroscopic surgery and more specifically, to portal access during arthroscopic surgery.

Background of the Inventions

Arthroscopy is a minimally invasive procedure for

treating joint pathology and is a superior alternative to open joint arthrotomy. Arthroscopy has the advantage of less disruption to the joint tissues, and potentially faster healing. The scope of joints and pathologies that can be treated with arthroscopy has grown dramatically, and now includes hip, spine, and small joint procedures in addition to the traditional knee and shoulder procedures. However, arthroscopy remains a technically demanding procedure, and new instrumentation and procedures are constantly being developed. Access to difficult to reach parts of the joint remains a significant challenge. While curved and flexible instruments are available to access these hard to reach areas of the joint, access portal devices have not kept up with the

instrument advances. Some attempts have been made to develop flexible portals, however these have significant drawbacks either in being only slightly flexible, being very difficult to use, or being incompatible with standard portal placement techniques and instrumentation. For example, the Arthrex® PassPort Button Cannula™ is a rubbery cannula that provides instrument mobility in shoulder operations. However, delivery of the device is non-standard, requiring the surgeon to fold the device in half with a hemostat before insertion. What is needed is an instrument system that allows a high level of flexibility, high instrument mobility, and high ease of use while retaining compatibility with standard cannula placement techniques involving switching sticks and guide wires.

Summary

The system described below provides for easy insertion of a flexible portal cannula into a surgical portal. The system includes a flexible portal cannula paired with a specialized driver that engages the cannula from the inside near the distal tip and pushes the cannula into the surgical portal, essentially pulling the proximal portion of the cannula from its distal tip while being pushed from the proximal end with the specialized driver. This provides an easy way to put a flexible cannula in place without "pushing a rope" or folding the cannula and forcing it through an incision with a

hemostat .

The system may use a single engagement near the distal tip of the portal cannula or a plurality of engagement

features distributed along the length of the portal cannula. The engaging features of the portal cannula may, for example, be proximally facing shoulders or an annular flanges, disposed on the inside of the cannula, to create annular grooves, which are paired with distally facing shoulders or projections on the outer surface of a driver. The distally facing shoulders or projections are sized and dimensioned to impact the

proximally facing shoulders and/or engage the annular grooves.

The system may use a split driver and corresponding multiple lumen cannula. This system provides for Single

Portal Arthroscopy (SPA), which can be used for stitching and passing sutures through one surgical portal, single portal laparoscopic procedures, and passing multiple instruments via a single portal incision.

The system provides a high level of flexibility, high instrument mobility, and high ease of use while retaining compatibility with standard portal placement techniques involving switching sticks and guide wires. The cannula also provides fluid management capability to maintain clarity in the joint. The devices described can be used for all types of arthroscopy including knee, shoulder, hip, small joint, and spine procedures.

Brief Description of the Drawings

Figures 1 illustrates an elastomeric portal cannula and driver system with paired engagement features.

Figure 2 illustrates the system of Figure 1 with the driver disposed within the elastomeric portal cannula.

Figure 3 illustrates the system of Figures 1 and 2 with a switching stick disposed within a lumen of a cannulated driver .

Figure 4 illustrates the cannulated driver.

Figure 5 illustrates the switching stick.

Figure 6 illustrates the elastomeric portal cannula.

Figure 7 is a detailed view of the mating engagement between the distal end of the driver and the elastomeric portal cannula.

Figure 8 illustrates a driver with a recess tip.

Figure 9 illustrates a driver with distally extending projections adapted to engage with the features of the inner wall of the elastomeric portal cannula. Figure 10 illustrates the system with a driver with a sharp trocar point.

Figure 11 illustrates the system with an

obturator/dilator . Figure 12 is a detailed view of the mating engagement between the driver distal end and the cannula of Figure 9.

Figure 13 illustrates the cannula.

Figure 14 illustrates the mating engagement between the obturator distal end and the cannula of Figures 11 through 13. Figure 15 illustrates an alternate mating engagement feature on an obturator/dilator .

Figure 16 illustrates an exploded view of a portal cannula and driver system having a plurality of gripping features . Figure 17 illustrates a driver with a plurality of cone shaped gripping features.

Figure 18 illustrates an exploded view of the system using a driver with a plurality of cylindrical gripping features . Figure 19 illustrates the system using a plurality of cylindrical gripping features.

Figure 20 illustrates the system of Figure 19 utilizing a plurality of cylindrical gripping features.

Figure 21 illustrates the cannula of Figure 20. Figure 22 illustrates the mating engagement between the plurality of cylindrical gripping features and the cannula of Figure 20. Figure 23 illustrates an exploded view of a multiple lumen system.

Figure 24 illustrates the multiple lumen system of Figure

23. Figure 25 illustrates an exploded view of a multiple lumen system using multiple engagement features.

Figure 26 illustrates a detailed view of the multiple lumen system of Figure 25.

Figure 27 illustrates the multiple lumen system in use. Figure 28 illustrates an exploded view of a seal design for a multi-lumen cannula.

Figure 29 illustrates a multi-lumen cannula.

Figure 30 illustrates a system using a spring-loaded driver . Figure 31 illustrates a spring-loaded driver.

Figure 32 illustrates a system using a spring-loaded driver .

Figure 33 is a detailed view of the mating engagement between the distal end of the spring-loaded driver and the cannula.

Figure 34 illustrates a system using a removable 0-ring and seal.

Figure 35 illustrates a system using a removable 0-ring and seal. Figure 36 illustrates a system using a removable 0-ring and seal. Figure 37 illustrates a system utilizing a distal septum seal .

Figure 38 illustrates a cannula with tissue compression and retraction. Detailed Description of the Inventions

Figure 1 illustrates an exploded view of the system for driving a cannula into a surgical site. The system includes a rigid driver 1, a cannula 2, and a switching stick 3. The cannula is delivered into place with a rigid tube 4 that has an interlocking feature at the distal tip that engages with a mating locking feature in the distal tip of the cannula

(further detailed in Figure 7). In this way, the proximal portion of the cannula is "pulled" into a surgical portal or incision from its distal tip as the distal tip is pushed. The system allows for the use of a "switching stick" or "Wissenger Rod" 3, a rod typically about 4mm in diameter that is used as a guide wire to place a cannula into a surgical portal. It should be appreciated that the driver cannulation and

switching stick is an optional feature. Figure 2 illustrates the system of Figure 1 when

assembled, with the cannula disposed over the rigid tube. The cannula shown has a side port 5 to allow fluid inflow and outflow from the joint, providing fluid management in order to maintain clarity in the joint during the arthroscopic surgical procedure. The cannula has a flexible distal flange 6 to retain the cannula in the joint, preventing it from backing out of the surgical site. An expandable distal wiper seal 7 may be provided to hold fluid in the joint and prevent fluid leakage. External retention ridges 8 are disposed over the exterior of the cannula.

The driver, as shown in Figures 3 and 4, comprises a handle 9 attached to the rigid tube 4. The driver maybe cannulated (as shown) through its core to allow for insertion of the switching stick (Figure 5).

Figures 6 and 7 detail the drive engagement 10 between the cannula and the driver. As shown in Figures 4 and 7, the distal tip 11 of the rigid tube of the driver has a distally extending protrusion 12, or segment of tubing, with a larger internal diameter than the remainder of the rigid tube. This creates a distally facing shoulder 13 for engagement with the proximally extending ring 14 of the cannula and distally extending ring 15 on the rigid tube that fits within the annular groove 16 of the cannula. With these components sized and dimensioned to engage each other, the rigid tube can be pushed distally into the cannula until the components are interlocked with the ring 15 disposed with the annular groove 16. Thereafter, the rigid tube and cannula are locked

together such that the rigid tube cannot be pushed distally out of the cannula. As shown in Figure 6, the cannula has a proximally extending lip 17 or ring 14 defining a groove 16 sized and dimensioned to receive the rigid tube distally extending protrusion 12.

In use, the driver is inserted into the proximal end of the cannula 18 until the distally extending protrusion 15 at the distal tip of the rigid driver engages the mating locking feature 16 in the cannula. When the driver is engaged, the cannula is supported by the rigid tube. The switching stick guide rod 3 is driven through the proximal end of the driver 19, through the driver, and out the distal end of the driver. The entire assembly comprising the switching stick, rigid driver and cannula are inserted into the surgical portal or incision. When the cannula is in the desired position in the surgical site, the switching stick is withdrawn, and then the rigid driver is withdrawn.

Other distal drive mechanisms can be utilized. Figure 8 illustrates a driver with a recess 20 or slot at its distal tip. The driver with recessed tip engages a protrusion in the interior distal end of the cannula (not shown). Rotation of the driver engages the protrusion in the distal tip of the cannula.

Figures 9 through 14 show embodiments where the driver protrudes out from the distal end of the cannula. Here, the engaging feature 10 on the driver is on the exterior of the rigid tube, rather than the distal extending protrusion as shown in Figures 1 through 7). A distally facing shoulder 13 engages with the proximally extending ring 14 of the cannula and distally extending ring 15 on the rigid tube that fits within the annular groove 16 of the cannula. The engagement can be in a flared arrangement as shown in Figure 14 or more of a rectangular or perpendicular arrangement as shown in

Figure 15. The drive engagement 10 is disposed just proximal to the distal tip of the driver 21 to allow for the distal tip of the driver to extend from the distal tip of the cannula 22. The obturator may be a solid dilator (shown in Figure 9), allowing the device to penetrate and dilate tough joint capsules like hip joints. The dilator feature protruding from the distal end may be a sharp trocar point 23, as shown in Figure 10. The protruding portion of the obturator may also be threaded to help in penetrating tough joint capsules, such as the hip capsule. The driver can be a cannulated obturator, with the cannulation being sized to accept a switching stick, a guide wire such as a K-Wire for use in spine surgery, or a nitinol guide wire for use in hip arthroscopy.

The driver and cannula can have a plurality of engaging features, as shown in Figures 16 through 22. Each of the driver gripping features 24 correspondingly mate with detents 25 disposed on the inside wall of the cannula. Rather than one engagement point at the distal tip, the engagement

features are distributed along the length of the cannula. The plurality of engagement features allow the driver to push longer and lower durometer flexible cannulas into a surgical portal. The driver may have a uniform diameter (Figure 16), graduated stepped cones (Figure 17), graduated stepped

cylinders (Figure 18), or other multiplicity of engaging features. The distal end of the driver may be flat (Figure 16 or 17) or cone-shaped (Figure 18). Figures 20 through 22 detail the drive engagement. Distally facing shoulder 24 of the driver engages with a proximally facing shoulder 25 of the cannula.

Figure 23 illustrates an exploded view of a multiple lumen system, including a split driver 26 and a multiple lumen cannula 27. The split driver is configured to engage and correspondingly drive a multi-lumen portal. The system can be used for stitching and passing sutures through one portal in an arthroscopic workspace, single portal laparoscopic

procedures ("SPL"), and passing multiple instruments via a single portal incision (see Figure 27). As shown in Figure 24, the driver is inserted through the cannula. The cannula may have two lumens (Figure 23), three lumens (Figure 25 and 26) or more. The driver will be split in a corresponding way (two for two, three for three, etc.). Figure 23 illustrates one engagement feature at the distal tip while Figure 25 shows multiple engagement features 28 along the length of the driver. The alignment mark 29 assists the user in aligning the driver with the lumens of the portal.

Figures 28 and 29 illustrates a seal design for use with a multiple lumen cannula for use with a single portal

arthroscopy system. The round holes 30 act like traditional wiper seals found on standard cannulas, and the chevron shaped cuts 31 provide an additional seal behind the wiper seal that closes against the round hold with hydrostatic pressure. The design can also have a septum seal slit behind the wiper seal. Figures 30 to 33 illustrates a driver with an expandable engagement mechanism. A spring steel inner driver 32 is disposed within a tube 33 wherein the spring steel inner driver expands when it is pushed out distally past the end of the tube. The expanding ring 34 disposed at the distal end of the driver engages an undercut feature 35 in the flexible cannula, allowing the flexible cannula to be pushed into a surgical portal. The driver collapses when released for easy removal. The driver may optionally be cannulated to accept a switching stick.

The cannulas described herein are a flexible portal made of an elastomer with a hardness range from Shore 10A to 40D. The material may be a moldable TPE (thermoplastic elastomer) or moldable silicone thermoset or thermoplastic elastomers (such as GLS Versaflex HC 2110-43N, PolyOne, Avon Lake OH) urethanes, Kraton, Santoprene, or liquid injection molded silicone, or compression molded silicone (such as Dow Corning C6-150 or C6-540). Because the portal is made of a flexible moldable material, the lumen can be molded to have a

traditional circular cross section or a rectangular or square cross section to accommodate instruments with a rectangular or square cross section. For example, various devices for shoulder repair have square cross-sectional shafts rather than the traditional round shafts (example: the Tornier

ArthroTunneler® ) . The square shafted instrument, in

combination with a compatible cannula with a square cross section, results in a minimal cross-section when the

instrument is placed therein.

Since the elastomer is tacky, the inner surface may be coated with a water-based biocompatible lubricant (available from AST Products (Billerica, MA) or Surmodics (Eden Prairie, MN) ) . The driver/obturator may be coated as well. In

addition to the lubricious surface treatments, lubricious additives may be added to the cannula. These include any biocompatible additive to increase dry and wet lubricity of a molded low-durometer TPE, including barium and silicone oils. Other additives include PTFE powder and perfluoropolyether synthetic oil (available from Foster Corporation (Putnam, CT)).

Various seals can be used with the cannula, including a septum and wiper seal assembly 41, as shown in Figure 18 and a triple flap seal 42 as shown in Figure 25. The cannula may have a proximal fluid seal. The proximal seal may have a hemispherical shape to help the septum seal stay closed by hydrostatic pressure. The proximal fluid seal may be welded to the cannula with RF or ultrasonic welding if a TPE

thermoplastic, or assembled by joining the silicone parts together before the thermoset is fully cured, and the parts weld together during the curing process. The seal and the cannula body may be molded of the same material, thus saving cost, and allowing thermoplastic TPE parts to be easily welded together .

The cannula may have a sphincter-like seal 43 at the proximal end with a removable O-ring 44, as shown in Figures 34 to 36. When the O-ring is in place it makes a tight, reliable leak-resistant seal that is superior to a 3-layer septum seal. Also when the O-ring is removed, the seal will be easier to stretch open, allowing larger items to be passed through the seal such as biologic implants like sheet graft repairs constructs. It can also be held open with a tube or slotted cannula. Figure 37 shows a distal septum seal 45.

Figure 38 illustrates a cannula with a tissue compression and retraction feature. It is desirable to put traction on tissue inside the joint especially during labral (SLAP) repairs where tissue drops down and gets in the surgeons field of view. The elastomeric retention and retraction flange 36 folds back when the cannula is inserted. The distal flange 36 pulls this tissue back, and the side clip 37 keeps traction on the flange to keep the tissue retracted. Ridges 38 on the shaft of the cannula allow for incremental adjustment of compression and keep the clip from slipping. The clip can easily be slipped onto the cannula after insertion to the desired compression.

Generally, the cannula is a flexible portal cannula for use in conjunction with the cannula driver. The cannula driver comprises a shaft having a distal end and a proximal end and at least one distally extending projection extending from its distal end, or extending distally from the outer surface of the driver proximate its distal end. The flexible portal cannula comprises a flexible tube, characterized by a proximal end and a distal end and a lumen extending from the proximal end to the distal end of the flexible tube. The distal end of the flexible tube is adapted for insertion into a surgical site through a surgical portal. The flexible tube has a proximally facing groove disposed on an inner surface thereof, proximate its distal end, which is sized and

dimensioned to receive a distally extending projection of the cannula driver. The proximally facing groove can be an annular groove entirely circumscribing the inner diameter of the portal cannula, or it may extend merely partially around the inner diameter. As illustrated, the groove is most conveniently formed by a ring extending proximally within the distal tip of the portal cannula. The ring can be suspended or fixed to an inwardly protruding flange which protrudes inwardly from the inner wall of the portal cannula, but can also be fixed directly to, or depend directly from, the inner wall of the portal cannula. The driver may be a solid shaft, but is preferably hollow, with a lumen suitable for passage of a switching stick. Also, the driver may be split

longitudinally, into two or more elongate sections, to be used in conjunction with a portal cannula having two or more lumens separated by longitudinally extending webs, where the webs are sized to fit in the space separating the elongate sections, to provide a system for inserting multi-lumen portal cannulae.

While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. The elements of the various embodiments may be incorporated into each of the other species to obtain the benefits of those elements in combination with such other species, and the various beneficial features may be employed in embodiments alone or in combination with each other. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.