Pneumatic actuator for dispensing surgical staples

The pneumatic actuator for dispensing surgical staples is a handheld actuator for use with a typical staple cartridge. A source of pressurized fluid is used to automatically drive forward movement of a plunger rod. As in a conventional, manually-driven surgical stapler, the forward movement of the plunger rod is used to actuate the surgical stapler to bend and eject a staple. The pneumatic actuator may be used with any suitable type of surgical staple cartridge, through coupling of the plunger rod thereto. The pneumatic actuator for dispensing surgical staples includes a housing having an upper portion, for receiving the pressurized fluid to drive the plunger rod, and a lower portion, which is configured to act as a gripping handle for the user. A finger-actuated trigger is further provided, allowing for single finger release of the pressurized fluid to reset the pneumatic actuator for a surgical stapler.

BACKGROUND

The present invention relates to medical devices, and particularly to a pneumatic actuator for a surgical stapler.

2. Description of the Related Art

FIGS. 2A and 2Bshow a typical, prior art surgical stapler. As shown, surgical stapler100includes a housing or casing140, with a rear portion102thereof being substantially tubular and having a handle103extending downwardly therefrom. A front end104of rear portion102is tapered for receiving a rear end105of a smaller diameter, front portion106of casing140. As shown, front portion106and rear portion102define an elongated barrel for slidably supporting a plunger107. A control sleeve108is rotatably mounted on one end of the plunger107. The plunger107and the sleeve108are biased to the rest position (shown in the configuration ofFIG. 2A) by a helical spring111. The spring111is mounted on the plunger107and extends between an internal shoulder112near the tapered end of the rear portion102of the casing140and a sleeve113, which is fixedly mounted on the plunger107in front of the control sleeve108. The sleeve113includes a rear flange114, extending radially inwardly for retaining the spring111.

A trigger115is pivotally connected to the casing140in front of the handle103for rotation around a screw116. The end of the trigger115within the casing140is bifurcated, with the two arms thereof defining lugs117(only one is shown for purposes of simplification), which lie on either side of the plunger107within a gap between the front end of the sleeve108and the rear end of the sleeve113. When the trigger115is squeezed towards the handle103, the lugs117press against the rear end of the sleeve113to move the plunger107forwardly, compressing the spring111.

When the stapler100is put into an operative state, the plunger107can be moved forward a distance sufficient to discharge a staple from a staple cartridge. As shown inFIGS. 2A and 2B, the plunger107is defined by an elongated rod with a threaded hole128for securing the rear end of plunger107to casing140by a threaded screw or the like. The outer or front end of the plunger107is flared slightly and cut away to define a shoulder132, which bears against a staple133when the staple133is placed on a support surface34at the front end of the casing140.

The leading edge135of the casing140includes a shoulder which defines a generally V-shaped anvil for deforming the staple133in conjunction with a post137. When the plunger107is forced forwardly, arms of the staple133are deformed by the anvil to define a tight loop, similar to the bending or folding of a conventional staple. As noted above, in order to actuate the surgical stapler, the surgeon must squeeze trigger115towards handle103. Given the delicate and precise nature of surgical procedures, the manual force required to actuate the surgical stapler via trigger115could cause the surgeon's hand to slightly move or shake, resulting in misplacement of the staple and/or injury to the patient. Similarly, the mechanical shock generated by the sudden thrust forward of plunger107could cause the surgical stapler to move or vibrate in the surgeon's hand. Thus, a pneumatic actuator for dispensing surgical staples solving the aforementioned problems are desired.

SUMMARY

The pneumatic actuator for dispensing surgical staples is a handheld actuator for use with a surgical stapler. A source of pressurized fluid is used to automatically drive forward movement of a plunger rod. As in a conventional, manually-driven surgical stapler, the forward movement of the plunger rod is used to actuate the surgical stapler to bend and eject a staple, and the pneumatic actuator for dispensing surgical staples may be used with any suitable type of surgical stapler, through coupling of the plunger rod thereto.

The pneumatic actuator includes a housing having an upper portion, a central portion and a lower portion. A longitudinally extending hollow chamber is formed in the upper portion of the housing and a flow passage is formed in the central portion of the housing. The lower portion of the housing is adapted for gripping by the hand of a surgeon or other medical practitioner. A feed line is at least partially mounted within the lower portion of the housing for receiving pressurized fluid from an external source, such as a tank of pressurized fluid, an air compressor or the like. The feed line is in selective fluid communication with the flow passage formed in the central portion of the housing, with a first valve selectively controlling the flow of the pressurized fluid from the feed line to the flow passage formed in the central portion of the housing. A button, knob or the like is preferably mounted on the lower portion of the housing and is mechanically coupled to the first valve for selective opening and closing thereof.

A piston is slidably received in the longitudinally extending hollow chamber, dividing the longitudinally extending hollow chamber into a front portion and a rear portion. The piston provides a fluid-tight seal between the front portion and the rear portion and is elastically biased against a front wall of the upper portion of the housing. The flow passage is in open fluid communication with the rear portion of the longitudinally extending hollow chamber. A guide tube is mounted to the front wall of the upper portion of the housing and extends longitudinally therefrom. A plunger rod is secured to the piston and extends longitudinally to be at least partially received by, and slidably supported within, the guide tube.

In use, the user selectively opens the first valve such that the pressurized fluid flows through the flow passage formed in the central portion of the housing and into the rear portion of the longitudinally extending hollow chamber to urge the piston forwardly therein. The forward movement of the piston pushes the plunger rod forwardly within the guide tube, and the plunger rod is adapted for actuation of a surgical stapler upon its forward movement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The pneumatic actuator for dispensing surgical staples10is a handheld actuator for dispensing surgical staples. The pneumatic actuator10can be configured to include or be removably attached to any suitable staple cartridge, e.g., a staple cartridge including surgical staples and knife. A source of pressurized fluid, such as exemplary pressurized gas G (e.g., CO2) is used to automatically drive forward movement of a plunger rod20. As in a conventional, manually-driven surgical stapler, such as that shown inFIGS. 2A and 2B, the forward movement of the plunger rod20is used to actuate the staple cartridge to eject a staple which then slices and staples tissue in a conventional manner. It should be understood that the pneumatic actuator for dispensing surgical staples10may be used with any suitable type of staple cartridge through suitable coupling of the plunger rod20thereto.

As best seen inFIG. 3A, the pneumatic actuator for dispensing surgical staples10includes a housing12having an upper portion14, a central portion34and a lower portion16. A longitudinally extending hollow chamber42is formed in the upper portion14of the housing12, and a flow passage40is formed in the central portion34of housing12. The lower portion16of the housing12is adapted for gripping by the hand of a surgeon or other medical practitioner. A feed line50is at least partially mounted within the lower portion16of housing12for receiving pressurized fluid (such as exemplary pressurized gas G) from an external source, such as a tank of pressurized fluid, an air compressor or the like. The feed line50is in selective fluid communication with the flow passage40formed in the central portion34of housing12, with a first valve38selectively controlling the flow of the pressurized fluid from the feed line50to the flow passage40formed in the central portion34of housing12. As shown inFIG. 1, a knob36, button or the like is preferably mounted on the lower portion16of the housing12and is mechanically coupled to the first valve38for selective opening and closing of the valve38. The user may adjust the knob, as desired, to regulate or control the amount of pressure in the chamber42.

A piston22is slidably received in the longitudinally extending hollow chamber42, dividing the longitudinally extending hollow chamber42into a front portion44and a rear portion46. The piston22provides a fluid-tight seal between the front portion44and the rear portion46and is elastically biased against a front wall52of the upper portion14of housing12by a spring24or the like. The flow passage40is in open fluid communication with the rear portion46of the longitudinally extending hollow chamber42(through port56). A guide tube18is mounted to the front wall52of the upper portion14of housing12and extends longitudinally therefrom. A plunger rod20is secured to the piston22and extends longitudinally to be at least partially received by, and slidably supported within, the guide tube18, as shown.

In use, as shown inFIGS. 3A and 3B, the user selectively opens the first valve38(via actuation of knob36ofFIG. 1) such that the pressurized fluid (here shown as exemplary pressurized gas G) flows from feed line50, through the flow passage40formed in the central portion34of housing12, and into the rear portion46of the longitudinally extending hollow chamber42. The pressurized fluid entering rear portion46urges the piston22forwardly within hollow chamber42. The forward movement of the piston22pushes the plunger rod20forwardly within the guide tube18(FIG. 3B), and the plunger rod20is adapted for actuation of a surgical staple cartridge upon its forward movement. It should be understood that the knob36may be used to regulate the pressure in the rear portion46, as desired, e.g., to adjust pressure depending on the thickness of the tissue that is to be stapled.

Following the stapling operation, the user actuates a second valve for selectively releasing the pressurized fluid from the rear portion46of the longitudinally extending hollow chamber42. As shown inFIGS. 1 and 3A-3C, the second valve is preferably in the form of a finger-actuated trigger26, allowing for single-finger release of the pressurized fluid to reset the piston22, without the user having to release his or her grip in the lower portion16of housing12.

As best seen inFIGS. 3A-3C, an upper portion28of the finger-actuated trigger26is slidably received within a trigger chamber32formed in the central portion34of housing12. A release conduit54extends between the flow passage40and the trigger chamber32, such that the release conduit54is in fluid communication with the trigger chamber32through a port58. The upper portion28of the finger-actuated trigger26selectively seals the port58. As shown, the upper portion28of the finger-actuated trigger26is elastically biased within the trigger chamber32by spring60or the like.

Thus, as shown inFIG. 3C, in use, following stapling, in order to reset the piston22back to its original position, the user engages lower portion30of finger-actuated trigger26to slide the upper portion28back, opening port58. This allows the pressurized fluid to flow from rear portion46of longitudinally extending hollow chamber42into the flow chamber40. Since valve38is closed once stapling is finished, the pressurized fluid flows through release conduit54and out, into the environment, through port58. Once the user removes his or her finger from lower portion30of finger-actuated trigger26, the upper portion28is elastically biased to slide forward, again covering and sealing port58, returning piston22to its initial position, such that the pneumatic actuator for dispensing surgical staples10may again be used, as inFIGS. 3A and 3B.

Since the front portion44of longitudinally extending hollow chamber42is not assumed to be free of fluid, an air port62is formed through the upper portion14of the housing12such that the front portion44of the longitudinally extending hollow chamber42is in fluid communication with an external environment. During compression of spring24, and forward movement of piston22(FIGS. 3A and 3B), air is free to flow from front portion44into the external environment so that forward movement of piston22is not impeded. Similarly, during expansion of spring24, and rearward movement of piston22(FIG. 3C), air is free to flow from the external environment into the front portion44, such that rearward movement of piston22is not impeded.