Shield lockout for bladed obturator and trocars

A shielded bladed obturator is provided with a shield lockout that prevents retraction of a shield to expose a blade for cutting. The shield lockout in one aspect has a rotational switch interacting with a longitudinal extending shield to lock and unlock the shield. A blade exposure and coverage system is also provided.

BACKGROUND

This invention relates generally to trocars or access ports used in endoscopic or laparoscopic surgeries and more particularly, to flat blade shielded obturators.

A surgical access port or trocar generally has a cannula and a valve housing coupled to one end of the cannula and an obturator inserted into the cannula has a shaft with a sharp blade or tip at one end of the shaft. In operation, the trocar cannula extends across a body wall, e.g., the abdominal wall, providing access into a body cavity, such as the abdominal cavity. The obturator facilitates the placement of the trocar by puncturing and/or penetrating the tissue forming the body wall.

In one example, the obturator is inserted through the cannula and its sharp bladed tip extends beyond one end of the cannula. The sharp bladed tip of the obturator cuts tissue as the trocar and obturator are moved through the body wall. Once the trocar and obturator are operatively positioned, the obturator can be removed from the trocar body leaving the cannula to provide working-channel access into the body cavity.

With the body wall penetrated, the sharp bladed tip can be covered or protected. For example, a spring-loaded tubular safety shield which surrounds the shaft of the obturator may move forward to cover the tip of the obturator once resistance to the movement of the safety shield, e.g., from the body wall, is removed. As such, the cutting stops once the body wall has been penetrated. However, a relatively large force may be required to cause the tip of an obturator to penetrate the body wall. Once the tip penetrates the body wall, resistance to penetration is removed and the tip of the obturator is suddenly free to reach into the body cavity and cause additional cutting. Failure to stop this cutting action can result in complications. Obturators having spring-loaded tubular safety shields may require larger incisions and may require considerable time to move the shield to cover the tip, the shield possessing a relatively large mass.

SUMMARY

Generally, a flat blade shielded obturator is provided. A shield lockout is provided that facilitates assembly, enhances reliability and reduces complex mechanisms. In one aspect, an obturator comprises a handle having a switch movable from a first, locked position to a second, unlocked position. The switch has a first section and a second section. Connected to the handle, the obturator also has a shaft having a movable portion and a fixed portion with a blade connected to the fixed portion of the shaft. The shaft has a longitudinal axis. The switch in the first position has the first section of the switch obstructing the movable portion of the shaft to prevent movement of the movable portion of the shaft along the longitudinal axis. In the second position, the switch has the second section of the switch obstructing the movable portion of the shaft and allowing movement of the movable portion of the shaft along the longitudinal axis.

In one aspect, the first section of the switch is a first arm coupled to a user accessible tab and the second section of the switch is a second arm smaller than the first arm. The second arm is deflectable in a direction parallel to the longitudinal axis of the shaft. The first arm is not deflectable. The user accessible tab and first section may be movable to the second position with the user accessible tab returning to the first position while the first section remains in the second position. The obturator may have a wall within the handle that is exposed when the switch is moved to the second position. The second section is movable along a direction parallel to the longitudinal axis. The first section is not movable along a direction parallel to the longitudinal axis. The first and second sections are rotatable about a longitudinal axis offset from and parallel to the longitudinal axis of the shaft. The obturator further comprises a ramp obstructing movement of the switch in the second position and allowing movement of the switch in the first position. The ramp has a first, low profile end and a second, high profile end. The second section of the switch is adapted to ride along the ramp while deflecting and to snap into a locked position along a back wall of the ramp, juxtaposed to the high profile end of the ramp, thereby locking the switch into the second position. The second section may be a spring. The second section may be more resilient than the first section.

Many of the attendant features of the present invention will be more readily appreciated as the same becomes better understood by reference to the foregoing and following description and considered in connection with the accompanying drawings in which like reference symbols designate like parts throughout.

DETAILED DESCRIPTION

InFIGS. 1-13, an obturator50has a handle60and a shaft70. The handle60has a switch100movable from a first, locked position to a second, unlocked position. The switch100has a first section, or arm106, and a second section, or arm116, each extending from a pivot post114. The shaft70is connected to the handle60and has a longitudinal axis. The shaft70has a movable portion, or shield102, and a fixed portion72. A blade104is connected to a distal portion74of the fixed portion72of the shaft70and extends distally beyond a distal end76of the fixed portion of the shaft. The movable portion102of the shaft70functions as a blade shield and is movable between a first, distal position, wherein it inhibits contact with the blade104to prevent cutting, to a second, proximal position, wherein the blade is exposed for cutting. With the switch100in the first, locked position, the first section106of the switch obstructs the shield portion102of the shaft70to prevent movement of the shield along the longitudinal axis. With the switch100in the second, unlocked position, the second section116of the switch obstructs the shield102, but allows the shield to move proximally along the longitudinal axis, thereby exposing the blade104.

As indicated above, the switch100is manipulated by a user, e.g., a surgeon, to manually unlock the movable portion, or shield102of the shaft70, allowing the blade shield to travel proximally, thereby exposing the blade104for cutting. The movable portion102of the shaft70has a shield shaft110that is adapted to move proximally into the handle60of the obturator50. When the switch100is in the locked position (FIG. 1), it overlaps a proximal end108of a shield shaft110which extends through a center of a base plate112.

The switch106is rotatable about a pivot post114mounted on the base plate112offset from the longitudinal axis of the shaft. As the switch106rotates to unlock the shield102, the proximal end108of the shield shaft110is unobstructed and allowed to retract proximally into the handle100(FIG. 2). The switch100is held in the unlocked position by the second arm116of the switch. The second arm116, which is deflectable in a direction parallel to the longitudinal axis of the shaft70, locks on the back side118of a ramp120extending from the base plate112. More particularly, the ramp120has a first, low profile end140and a second, high profile end142. The second arm116of the switch100is adapted to ride along the ramp120while deflecting and to snap into a locked position along the back side118of the ramp, which is juxtaposed to the high profile end of the ramp, thereby locking the switch into the second position. The ramp120obstructs movement of the switch100in the second position and allows movement of the switch in the second position. While the second arm116is deflectable, the first arm106is not deflectable.

When the trocar assembly122is inserted through an abdominal wall, the shield102retracts due to insertion pressure on the distal tip124of the shield. The proximal end108of the shield shaft110makes contact with the second arm116which is locked on the back wall118of the base plate ramp120. As contact is made, the shield shaft110lifts the second arm116up over the ramp120releasing the switch100. A torsion spring126connected between the base plate112and switch100forces the switch back to its original position. However, the switch100stops short as the first arm106of the switch is biased against the proximal end108of the shield shaft110while the shield102is retracted during insertion. As the obturator128clears the inside edge of the abdominal wall, the shield102, which is compressing a compression spring130(FIG. 22) between itself and the base plate112, is allowed to extend back forward to a shielded position, thereby preventing the blade104from performing additional cutting. As the proximal end108of the shield shaft110moves distally beyond contact with the second arm116of the switch, the shield shaft releases or no longer obstructs the spring loaded switch100, thereby allowing the switch to return back to its original, locked position (FIG. 1).

In one aspect, a torsion126(FIG. 9), extension132(FIG. 12), compression (not shown), or flat spring134(FIG. 13) is provided to bias the switch100to an initial position. The switch106and spring, in one aspect, is combined into one part where the spring is a wire form or single molded configuration that forms the switch, the torsion spring, and the second arm (not shown). In one aspect, the switch136is a single piece and the spring138(a wire form or single molded piece) incorporates the second arm (FIGS. 14a-14c).

InFIGS. 15a-15dand16a-16d, a slide switch200is utilized. The switch200has a clearance hole202in the center for the shield shaft204. The hole202in the switch200is offset (FIGS. 15aand16a), which locks the shield, i.e., preventing retraction of the shield. As the switch200is slid to one side (FIGS. 15band16b), the switch hooks onto a fixed latch206, unlocking the shield. The hole202in the switch200is now aligned with the shield shaft204and the shield shaft is free to retract. As the shield shaft204retracts, a projection208, extending from the shield shaft, contacts the switch200(FIGS. 15cand16c). The switch200is lifted, which disengages the switch from the fixed latch206(FIGS. 15dand16d). An extension spring210pulls the switch200to resist disengagement of the switch from the fixed latch206. As the shield shaft204extends back to its original position, the switch200, under spring force, returns back to its locked position (FIG. 15a).

Referring toFIGS. 17-22, in one aspect, a multiple piece switch300is utilized. As such, after being moved to an unlocked position (FIG. 19), if a portion or component of the switch300accessible by a user were interfered or blocked, other portions of the switch continue to operate and thus the shield302can be re-locked after use. The switch300has a first section, or arm318, a second section, or arm332, and a third section, or tab portion324having a tab342and a tab arm344. InFIG. 18, the switch300is in an initial or resting state. A torsion spring306is assembled on the same pivotal post308as the switch300. Switch300is rotatable about a longitudinal axis offset from and parallel to the longitudinal axis of the shaft338. A first leg310of the torsion spring306will rest against the base plate312along the flat surface314to the upper right of the post308inFIG. 18. A second leg316of the torsion spring306will rest against the first arm318(FIG. 19) of the switch to keep the tab portion324pressed against the wall320when in this state. The wall320is exposed when the tab portion324of the switch is moved to the second position. A spring, such as a leaf spring322, coupled to the tab portion324of the switch300, is not pre-loaded, but rests along the female portion of the boss pin (not shown) attached to the cover326. The leaf spring322may be formed integrally with the tab portion324to facilitate manufacturability and assembly of the switch300.

InFIG. 19, as the user slides the tab342to rotate the switch300to unlock the blade shield302(FIG. 17), the tab presses against the first arm318of the switch at the flat interface328, such that the tab, first arm318and second arm332of the switch rotate together. This causes the thin second arm332of the switch300to move or deflect up the ramp334and hook the back side340of the ramp. The second arm332is movable or deflectable along a direction parallel to the longitudinal axis of the shaft338, while the first arm318is not deflectable. More particularly, the ramp334has a first, low profile end348and a second, high profile end350. The second arm332of the switch300is adapted to ride along the ramp334while deflecting and to snap into a locked position along the back side340of the ramp, which is juxtaposed to the high profile end of the ramp, thereby locking the switch into the second position. The ramp334obstructs movement of the switch300in the second position and allows movement of the switch in the first position. The leaf spring322on the tab portion324of the switch300is now compressed and deformed against the cover boss pin. This causes a small moment on the tab portion324in the clockwise direction.

Once the user ceases to apply a load to the switch300(i.e., removes his or her finger from the tab342), the tab portion324will automatically return to a nearly closed position (FIG. 20a) while the first arm318remains in the second position. In this state, the locking mechanism is disabled or unlocked. The blade shield302is free to move, allowing the blade336to cut. As the blade shield302retracts far enough to expose the blade336for cutting, the proximal end346of the shaft338forces the second arm332of the switch300over the ramp334. The torsion spring306will force the first arm318and second arm332of the switch300clockwise, back into the locked position against the proximal end346of the shield shaft338until the compression spring130pushes the shield302toward covering the blade336, in which the second arm332of the switch300resets back to its original, locked position (FIG. 18). Meanwhile, the tap portion324remains stationary in this nearly closed position to prevent the user from interfering with the locking mechanism.

Accordingly, the present invention provides a bladed shielded obturator. Although this invention has been described in certain specific embodiments, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise than specifically described, including various changes in the size, shape and materials, without departing from the scope and spirit of the present invention. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive, the scope of the present invention to be determined by the appended claims and their equivalents rather than the foregoing description.