Patent Description:
Merely exemplary versions of trocars, components thereof, and other varieties of surgical access devices are disclosed in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

<CIT> describes a trocar formed from a cannula and an interfitting obturator for penetrating body cavity walls in laparoscopic and endoscopic surgery. In an embodiment, the distal end of a linking member from the shielded obturator is received through an opening in the canula and engaged in a trigger mounted in the cannula. A guiding tab from the shielded obturator is received in a second opening in the cannula. In an alternative embodiment, the guiding tab and the distal end of the linking member from the shielded obturator are interlockingly received in the openings of the cannula. By depressing push buttons, the guiding tab and linking member can be disengaged, allowing for easy separation of the shielded obturator from the cannula.

<CIT> describes a trocar assembly which may include a trocar, a seal cartridge releasably coupled to the trocar, and a trocar bushing that may be releasably coupled to a proximal end of the seal cartridge. The trocar includes a trocar housing and a cannula that extends distally from the trocar housing. The seal cartridge may be at least partially received within the trocar housing and include one or more actuatable latches that releasably couple the seal cartridge to the trocar housing. The trocar bushing may include a bushing housing that provides one or more actuatable latches that releasably couple the trocar bushing to the seal cartridge. In an embodiment, the trocar bushing may be releasably coupled to the seal cartridge by receiving the actuatable latches of the bushing housing into corresponding latch apertures defined on the proximal end of the seal cartridge.

<CIT> describes a surgical instrument access port assembly and method of use. The surgical instrument access port a surgical instrument has a needle lumen and a surgical access port. The needle lumen extends in a longitudinal direction and includes a needle tip at a distal end, and a body portion at a proximal end, the body portion having at least one recess or finger. The surgical access port has a cannula defining a hollow cannula shaft, and a tapered hub attached to a proximal end of the cannula. The tapered hub includes at least one inner ring configured to abut against the at least one recess or finger while the surgical instrument is inserted into the cannula of the surgical access port.

While various kinds of surgical instruments, including surgical access devices and end effectors, and other associated components have been made and used, it is believed that no one prior to the inventor(s) has made or used the invention described in the appended claims.

The accompanying drawings, together with the description of the embodiments given below, serve to explain the principles of the present invention. Embodiments of the invention are described in section II, and illustrated by <FIG>.

The following description of certain examples of the invention should not be used to limit the scope of the present invention, which is defined by the appended claims.

For clarity of disclosure, the terms "proximal" and "distal" are defined herein relative to a surgeon, or other clinician, grasping a surgical device. The term "proximal" refers to the position of an element arranged closer to the surgeon, and the term "distal" refers to the position of an element arranged further away from the surgeon. Moreover, to the extent that spatial terms such as "top," "bottom," "upper," "lower," "vertical," "horizontal," or the like are used herein with reference to the drawings, it will be appreciated that such terms are used for exemplary description purposes only and are not intended to be limiting or absolute. In that regard, it will be understood that surgical instruments such as those disclosed herein may be used in a variety of orientations and positions not limited to those shown and described herein.

Furthermore, the terms "about," "approximately," and the like as used herein in connection with any numerical values or ranges of values are intended to encompass the exact value(s) referenced as well as a suitable tolerance that enables the referenced feature or combination of features to function for the intended purpose(s) described herein.

<FIG> depict exemplary surgical access devices in the form of a single-use first trocar (<NUM>) and a reusable second trocar (<NUM>), each configured to provide surgical site access in a laparoscopic surgical procedure. Each trocar (<NUM>, <NUM>) includes a cannula assembly (<NUM>, <NUM>) having a working channel (<NUM>, <NUM>), and an obturator (<NUM>, <NUM>) configured to be removably inserted coaxially into the working channel (<NUM>, <NUM>) so that the assembled trocar (<NUM>, <NUM>) may be directed distally through the abdominal wall of a patient and into the abdominal cavity, for example as described below in connection with <FIG>.

As shown in <FIG>, cannula assembly (<NUM>) of single-use trocar (<NUM>) includes a cannula (<NUM>) and a seal housing (<NUM>). Cannula (<NUM>) and seal housing (<NUM>) cooperate to define working channel (<NUM>), which extends longitudinally along a central axis (A) of trocar (<NUM>). In particular, working channel (<NUM>) is defined by a lumen of cannula (<NUM>) in communication with a hollow interior of seal housing (<NUM>). Cannula assembly (<NUM>) is configured to receive elongate surgical instruments distally through working channel (<NUM>) to provide access to surgical sites within the abdominal cavity of a patient. As described in greater detail below, seal housing (<NUM>) houses a pair of seal structures defining a seal assembly configured to maintain insufflation of the patient's abdominal cavity while permitting passage of surgical instruments and tissue fragments along working channel (<NUM>).

Cannula (<NUM>) of the present version may include a bell-shaped hub (not shown) at a proximal end thereof, and an elongate cylindrical tube (<NUM>) extending distally from the hub and terminating at an angled cannula tip (<NUM>). An outer surface of cannula tube (<NUM>) includes a plurality of tissue gripping features in the form of annular ribs (<NUM>) arranged axially along a medial portion of cannula tube (<NUM>). Ribs (<NUM>) are configured to grip the layers of abdominal wall tissue through which cannula (<NUM>) is inserted, and thereby assist in stabilizing cannula (<NUM>) in axial and radial directions while cannula (<NUM>) is positioned within the opening formed in the abdominal wall of a patient.

More specifically, tissue gripping ribs (<NUM>) of the present example are formed as annular scallops in the sidewall of cannula tube (<NUM>) such that each rib (<NUM>) tapers radially inwardly in a distal direction from a radially outermost edge of the rib (<NUM>). The radially outermost edges of ribs (<NUM>) are thus generally flush with the non-ribbed proximal and distal portions of cannula tube (<NUM>). The resulting configuration of ribs (<NUM>) promotes advancement of cannula tube (<NUM>) through tissue layers in a distal direction and resists retraction of cannula tube (<NUM>) through the tissue layers in a reverse, proximal direction. Advantageously, this configuration protects against unintended withdrawal of cannula tube (<NUM>) from the abdominal wall of patient during a surgical procedure. It will be appreciated, however, that cannula tube (<NUM>) may be provided with various other types of tissue gripping features in other versions of trocar (<NUM>). For instance, cannula tube (<NUM>) may include a tissue gripping feature in the form of one or more helical ribs that extend around at least a medial portion of cannula tube (<NUM>), and which may be scalloped similar to ribs (<NUM>).

Seal housing (<NUM>) of cannula assembly (<NUM>) includes a proximal housing portion (<NUM>) and a distal housing portion (<NUM>) to which proximal housing portion (<NUM>) is removably attached. Proximal housing portion (<NUM>) includes a proximal head (<NUM>) and a distal base (<NUM>) secured together. Distal housing portion (<NUM>) includes a distal shroud (<NUM>) that encircles the proximal hub (not shown) of cannula (<NUM>), a cap plate (<NUM>) secured to a proximal end of distal shroud (<NUM>), and a latch ring (<NUM>) rotatably disposed therebetween and having a radially outwardly projecting tab (<NUM>). Latch ring (<NUM>) is selectively rotatable via tab (<NUM>) about the central axis (A) of trocar (<NUM>) between a locked position and an unlocked position. In the locked position, latch ring (<NUM>) locks proximal housing portion (<NUM>) to distal housing portion (<NUM>). In the unlocked position, latch ring (<NUM>) permits separation of proximal housing portion (<NUM>) from distal housing portion (<NUM>), for example to directly access a distal seal structure (not shown) housed within distal housing portion (<NUM>). In some versions, distal shroud (<NUM>) may be formed integrally with the proximal end of cannula tube (<NUM>) such that distal shroud (<NUM>) is a component of cannula (<NUM>).

Though not shown, proximal housing portion (<NUM>) houses a proximal (or "outer") seal structure, and distal housing portion (<NUM>) houses a distal (or "inner") seal structure, both arranged along the central axis (A) of trocar (<NUM>). The proximal and distal seal structures cooperate to define a seal assembly that maintains insufflation of the patient's abdominal cavity during a surgical procedure while permitting passage of surgical instruments and tissue fragments along working channel (<NUM>). For instance, the proximal seal structure may include an annular seal member configured to sealingly engage the shaft of a laparoscopic surgical instrument directed through working channel (<NUM>). The distal seal structure may include a duckbill seal member configured to maintain working channel (<NUM>) in a sealed stated in the absence of a surgical instrument shaft.

Cannula assembly (<NUM>) further includes an insufflation port (<NUM>) operatively coupled with the proximal end of cannula (<NUM>) and having an adjustable valve in the form of a stopcock (<NUM>). Insufflation port (<NUM>) is configured to direct insufflation fluid, such as carbon dioxide, from a fluid source (not shown) distally through working channel (<NUM>) and into the patient's abdominal cavity to thereby expand (or "insufflate") the cavity with the fluid. This expansion of the abdominal cavity creates additional space for performing a laparoscopic surgical procedure with improved ease.

As shown in <FIG> and <FIG>, obturator (<NUM>) of trocar (<NUM>) includes a proximal head (<NUM>), an elongate cylindrical shaft (<NUM>) extending distally from head (<NUM>), and a tapered distal tip (<NUM>). Obturator shaft (<NUM>) is configured to be received within working channel (<NUM>) of cannula assembly (<NUM>) such that obturator tip (<NUM>) extends through and distally of cannula tip (<NUM>). Obturator head (<NUM>) includes a domed upper body (<NUM>), a base plate (<NUM>), and an actuatable latch member (<NUM>), which includes a pair of latch arms (<NUM>) and a corresponding pair of latch buttons (<NUM>). Latch arms (<NUM>) are configured to be captured within respective slots (<NUM>) (See <FIG>) formed in a top surface of seal housing head (<NUM>) to couple obturator (<NUM>) with cannula assembly (<NUM>). Latch buttons (<NUM>) are actuatable to release latch arms (<NUM>) from the slots (<NUM>) and thereby permit separation of obturator (<NUM>) from cannula assembly (<NUM>). Obturator (<NUM>) further includes a central passage (<NUM>) that extends longitudinally through obturator head (<NUM>) and obturator shaft (<NUM>), and is configured to receive an endoscope (not shown) therein to provide visualization during insertion of trocar (<NUM>) through the abdominal wall of a patient. A clamp lever (<NUM>) of obturator head (<NUM>) is pivotable to selectively fix the endoscope within central passage (<NUM>). Central passage (<NUM>) and clamp lever (<NUM>) are merely optional features and may be omitted from obturator (<NUM>) in other versions.

Cannula assembly (<NUM>) and obturator (<NUM>) may be constructed to be disposed of after a single use with a patient. In other versions, one or more components of trocar (<NUM>) may be suitably constructed to withstand sterilization and multiple reuses, for example as described in greater detail below in connection with trocar (<NUM>) of <FIG>.

<FIG> illustrate an exemplary method of accessing an abdominal cavity (<NUM>) of a patient through the patient's abdominal wall (<NUM>) with trocar (<NUM>) described above. It will be appreciated that abdominal wall (<NUM>) includes outward superficial layers and inward deep layers. Superficial layers generally include an outer layer of skin (<NUM>) and an inner layer of fat (<NUM>); whereas the deeper layers include alternating layers of muscle (<NUM>) and fascia (<NUM>), which are fibrous and flexible with relatively higher tensile strength than the superficial layers.

As shown in <FIG>, with obturator (<NUM>) received within cannula assembly (<NUM>) and connected to seal housing (<NUM>), a clinician manipulates trocar (<NUM>) via obturator head (<NUM>) and seal housing (<NUM>) to urge obturator tip (<NUM>) against skin (<NUM>) and inward toward abdominal cavity (<NUM>) while rotating trocar (<NUM>) back and forth. Continued inward urging of trocar (<NUM>) further directs obturator tip (<NUM>) and cannula tip (<NUM>) distally through the layers of fat (<NUM>) and fascia (<NUM>) and into cavity (<NUM>), as shown in <FIG>. As discussed above, this step may be facilitated with visualization provided by an endoscope (not shown) mounted within obturator (<NUM>). Once cannula (<NUM>) has reached a desired depth of insertion into cavity (<NUM>), the clinician releases obturator head (<NUM>) from seal housing (<NUM>) via depression of latch buttons (<NUM>), and then withdraws obturator (<NUM>) from proximally from cannula assembly (<NUM>), as shown in <FIG>. This renders working channel (<NUM>) of cannula assembly (<NUM>) free to receive surgical instruments distally therethrough for performing the laparoscopic surgical procedure. As described above, tissue engagement ribs (<NUM>) provided on cannula tube (<NUM>) grip the layers of tissue (<NUM>, <NUM>, <NUM>) of abdominal wall (<NUM>), thus providing cannula assembly (<NUM>) with at least a minimum degree of stability relative to abdominal wall (<NUM>). Upon completion of the laparoscopic surgical procedure, the clinician grasps seal housing (<NUM>) and withdraws cannula assembly (<NUM>) proximally from abdominal wall (<NUM>), as shown in <FIG>.

In some instances, it may be desirable to configure a trocar such that one or more components thereof may be sterilized and reused for multiple surgical procedures, while one or more other components may be easily and economically disposed of and replaced after each procedure. <FIG> show another exemplary trocar (<NUM>) that is configured in such a manner, and which is similar in structure and function to trocar (<NUM>) described above except as otherwise described below.

Similar to trocar (<NUM>), trocar (<NUM>) includes a cannula assembly (<NUM>) having a working channel (<NUM>) and an obturator (<NUM>) configured to be inserted into cannula assembly (<NUM>) coaxially along working channel (<NUM>). Cannula assembly (<NUM>) includes a cannula (<NUM>) having a bell-shaped hub (<NUM>) at a proximal end thereof, and an elongate cylindrical tube (<NUM>) extending distally from hub (<NUM>) and terminating at an angled cannula tip (<NUM>). An outer surface of cannula tube (<NUM>) includes a plurality of tissue gripping features in the form of annular ribs (<NUM>) arranged axially along a medial portion of cannula tube (<NUM>) and which are similar to ribs (<NUM>) described above.

Cannula assembly (<NUM>) further includes a seal assembly (<NUM>). Unlike the seal assembly defined by seal housing (<NUM>) of trocar (<NUM>), seal assembly (<NUM>) is constructed as a modular, replaceable unit configured to releasably mate with proximal hub (<NUM>) of cannula (<NUM>). As shown best in <FIG>, seal assembly (<NUM>) of the present example generally includes an upper frame member (<NUM>), a middle frame member (<NUM>), and a lower frame member (<NUM>) secured relative to one another in a coaxial arrangement. Though not shown, a proximal (or "outer") seal structure is supported within upper frame member (<NUM>), and a distal (or "inner") seal structure is supported within lower frame member (<NUM>). Such seal structures may be similar in structure and function to the proximal and distal seal structures of trocar (<NUM>) described above. Seal assembly (<NUM>) further includes an insufflation port (<NUM>) having an adjustable valve in the form of a stopcock (<NUM>).

A lower portion of seal assembly (<NUM>) distal to insufflation port (<NUM>) is configured to seat within proximal hub (<NUM>) of cannula (<NUM>) such than an annular seal member (<NUM>) disposed circumferentially about the lower portion sealingly engages an inner surface of cannula hub (<NUM>). In this manner, an interior of seal assembly (<NUM>) fluidly communicates with a lumen of cannula (<NUM>) to define a working channel (<NUM>) of cannula assembly (<NUM>) through which insufflation fluid, surgical instruments, and tissue fragments may be directed in the manners generally described above in connection with trocar (<NUM>). Seal assembly (<NUM>) may be further configured in accordance with one or more teachings of <CIT>; and/or <CIT>.

As shown best in <FIG>, obturator (<NUM>) of trocar (<NUM>) includes a proximal head (<NUM>), an elongate cylindrical shaft (<NUM>) extending distally from head (<NUM>), and a tapered tip (<NUM>) at a distal end of shaft (<NUM>). Obturator head (<NUM>) includes a domed upper body (<NUM>), a base plate (<NUM>), and an actuatable latch member (<NUM>), which includes a pair of downwardly extending latch arms (<NUM>) and a corresponding pair of latch buttons (<NUM>). Latch arms (<NUM>) are configured to be captured within respective slots (<NUM>) formed in a top surface of upper frame member (<NUM>) of seal assembly (<NUM>) to couple obturator (<NUM>) with cannula assembly (<NUM>). Latch buttons (<NUM>) are actuatable to release latch arms (<NUM>) from slots (<NUM>) and thereby permit separation of obturator (<NUM>) from cannula assembly (<NUM>).

Cannula (<NUM>) and obturator (<NUM>) of the present example are suitably constructed of a robust material, such as surgical steel, such that they may be sterilized and reused for multiple surgical procedures. In contrast, as described above, seal assembly (<NUM>) is constructed as a disposable unit, intended to be separated from cannula (<NUM>) and replaced after each procedure. For instance, seal assembly (<NUM>) may be constructed of various polymeric materials, including plastics and rubbers, such that seal assembly (<NUM>) may be easily manufactured and sold at a price point that renders seal assembly (<NUM>) suitable for disposal after a single use, similar to trocar (<NUM>) described above.

As mentioned above, each actuatable latch member (<NUM>, <NUM>) includes a respective pair of latch arms (<NUM>, <NUM>) and a corresponding pair of latch buttons (<NUM>, <NUM>). Respective latch arms (<NUM>, <NUM>) are configured to be captured within respective slots (<NUM>, <NUM>) of an assembled cannula assembly (<NUM>, <NUM>) to couple obturator (<NUM>, <NUM>) with cannula assembly (<NUM>, <NUM>). Additionally, latch buttons (<NUM>, <NUM>) are actuatable to release latch arms (<NUM>, <NUM>) from the slots (<NUM>, <NUM>) and thereby permit separation of obturator (<NUM>, <NUM>) from cannula assembly (<NUM>, <NUM>).

Therefore, latch member (<NUM>, <NUM>) may be used to couple obturator (<NUM>, <NUM>) with cannula assembly (<NUM>, <NUM>) while trocar (<NUM>, <NUM>) is used to access cavity (<NUM>) in accordance with the description herein. Once cannula (<NUM>, <NUM>) has reached a desired depth of insertion into cavity (<NUM>), the clinician may decouple obturator (<NUM>, <NUM>) from cannula assembly (<NUM>, <NUM>) by depressing latch buttons (<NUM>, <NUM>), and then withdrawing obturator (<NUM>, <NUM>) proximally from cannula assembly (<NUM>, <NUM>), as shown in <FIG>. The clinician may depress latch buttons (<NUM>, <NUM>) with one hand via a pinching motion with the thumb and another finger, such as the index finger. In other words, in order for the clinician to decouple obturator (<NUM>, <NUM>) from cannula assembly (<NUM>, <NUM>), the clinician must (A) depress latch buttons (<NUM>, <NUM>) to deflect latch arms (<NUM>, <NUM>) out of suitable engagement with cannula assembly (<NUM>, <NUM>), and (B) pull obturator (<NUM>, <NUM>) proximally relative to cannula assembly (<NUM>, <NUM>) while latch buttons (<NUM>, <NUM>) are suitably depressed in order to decouple obturator (<NUM>, <NUM>) from cannula assembly (<NUM>, <NUM>).

In order to actuate latch arms (<NUM>, <NUM>) via depression of latch buttons (<NUM>, <NUM>) in accordance with the description herein, latch arms (<NUM>, <NUM>) may require a suitable geometry to promote relatively easy actuation of latch arms (<NUM>, <NUM>) via depression of latch buttons (<NUM>, <NUM>). A suitable geometry of latch arms (<NUM>, <NUM>) may include a leaf-spring geometry having an aspect ratio that includes a relatively long length compared to thickness.

In instances where obturator (<NUM>) is configured to be sterilized and reused for multiple surgical procedures, the long and thin geometry of latch arms (<NUM>), for purposes of coupling and decoupling obturator (<NUM>) with cannula assembly (<NUM>), may leave latch arms (<NUM>) vulnerable to damage during the sterilization processes. Such damage may prevent actuatable latch member (<NUM>) from functioning in accordance with the description herein. For instance, a user who is cleaning and sterilizing a used obturator (<NUM>) may accidentally bend latch arms (<NUM>) relative to latch buttons (<NUM>) to such a degree that latch arms (<NUM>) are permanently damaged. Permanent damage of latch arms (<NUM>) may prevent latch buttons (<NUM>) from suitably decoupling latch arms (<NUM>) with cannula assembly (<NUM>) in accordance with the description herein.

As best seen in <FIG>, obturator (<NUM>) may include base plate (<NUM>) defining reinforcing slots (<NUM>) configured to help prevent unintentional damage to latch arms (<NUM>). Reinforcing slots (<NUM>) are dimensioned to house latch arms (<NUM>). In particular, reinforcing slots (<NUM>) may allow latch arms (<NUM>) to suitably deflect in response to depression of latch buttons (<NUM>) so latch arms (<NUM>) may couple and decouple obturator (<NUM>) with cannula assembly (<NUM>) in accordance with the description here. Additionally, reinforcing slots (<NUM>) may reinforce latch arms (<NUM>) to help prevent accidental damage during exemplary use and sterilization. For instance, reinforcing slots (<NUM>) may abut against portions of respective latch arms (<NUM>) in incidences of accidental contact, thereby reinforcing latch arms (<NUM>) help prevent accidental damage to latch arms (<NUM>).

However, the presence of base plate (<NUM>) and reinforcing slots (<NUM>) may create various other issues related to proper sterilization of obturator (<NUM>). For example, the area between base plate (<NUM>) and domed upper body (<NUM>) may become difficult to access for suitable sterilization. It may be difficult for a fluid to suitably enter or exit the interior area defined by base plate (<NUM>) and domed upper body (<NUM>) in order to suitably sterilize all surfaces of obturator (<NUM>) located within the interior area. As another example, external matter may become trapped in the interior area defined by base plate (<NUM>) and domed upper body (<NUM>) without suitable access to remove such matter.

Therefore, it may be desirable to have an obturator configured (A) to couple and decouple via a coupling assembly, and (B) to be suitably sterilized and reused for multiple surgical procedures while preventing unintentional damage to the coupling assembly.

<FIG> shows a proximal end of an obturator (<NUM>) that may be readily incorporated into trocar (<NUM>, <NUM>) in replacement of obturator (<NUM>, <NUM>) described above. Obturator (<NUM>) may be substantially similar to obturator (<NUM>) mentioned above, with differences described below. Therefore, obturator (<NUM>) may be suitably constructed of a robust material, such as surgical steel, such that obturator (<NUM>) may be sterilized and reused for multiple surgical procedures. Obturator (<NUM>) includes a proximal head (<NUM>), an elongate cylindrical shaft (<NUM>) extending distally from proximal head (<NUM>), and a tapered distal tip (<NUM>) (See <FIG>).

Elongate cylindrical shaft (<NUM>) and tapered distal tip (<NUM>) may be substantially similar to elongate cylindrical shaft (<NUM>, <NUM>) and tapered distal tip (<NUM>, <NUM>) described above. Therefore, cylindrical shaft (<NUM>) is configured to be received within working channel (<NUM>, <NUM>) of cannula assembly (<NUM>, <NUM>) such that obturator tip (<NUM>) extends through and distally of cannula tip (<NUM>, <NUM>).

Obturator head (<NUM>) includes a domed upper body (<NUM>), a base plate (<NUM>), and an interference fit coupling assembly (<NUM>). As will be described in greater detail below, interference fit coupling assembly (<NUM>) of obturator (<NUM>) is configured to suitably couple obturator (<NUM>) with cannula assembly (<NUM>) in order to form a trocar (<NUM>). As will also be described in greater detail below, interference fit coupling assembly (<NUM>) may be configured to (A) improve the robustness and/or durability of obturator (<NUM>) compared to actuatable latch member (<NUM>) of obturator (<NUM>), and (B) improve the cleanability of obturator (<NUM>) compared to obturator (<NUM>) by sealing off difficult to access areas for sterilization purposes.

In the current example, interference fit coupling assembly (<NUM>) includes a pair of spring clips (<NUM>) and a tapered shaft surface (<NUM>). Tapered shaft surface (<NUM>) extends from elongate shaft (<NUM>) toward base plate (<NUM>) such that the area of tapered shaft surface (<NUM>) closer to base plate (<NUM>) is wider than the area of tapered shaft surface (<NUM>) extending distally from base plate (<NUM>). As will be described in greater detail below, tapered shaft surface (<NUM>) is dimensioned to abut against a slanted upper surface (<NUM>) of seal housing (<NUM>) defining working channel (<NUM>) in order to promote the coupling of obturator (<NUM>) with cannula assembly (<NUM>) via friction fitting.

Each spring clip (<NUM>) includes a pair of legs (<NUM>) and a central portion (<NUM>). A proximal end of each leg (<NUM>) extends distally from a distal surface of base plate (<NUM>) in a tapered fashion such that the distal end of each leg (<NUM>) is closer to each other compared to the proximal end of each leg (<NUM>). The distal end of each leg (<NUM>) terminates into central portion (<NUM>) such that central portion (<NUM>) connects distal ends of each leg (<NUM>). Central portion (<NUM>) expands from the distal end of each leg (<NUM>) so the distance between the distal end of each leg (<NUM>) is closer than the distance between adjacent locations of central portion (<NUM>), as viewed from the perspective shown in <FIG>.

Legs (<NUM>), central portion (<NUM>), and the distal surface of base plate (<NUM>) define a pathway (<NUM>) that is open on both ends of spring clip (<NUM>). Spring clips (<NUM>) are formed of a sufficiently resilient material such that legs (<NUM>) and opposite sides of central portion (<NUM>) may flex inwardly relative to each other in response to an external compressive force, thereby altering the cross-sectional size of pathway (<NUM>). Additionally, spring clips (<NUM>) are formed of a sufficiently resilient material such that legs (<NUM>) and opposite sides of central portion (<NUM>) may expand back to their original shape once the external compressive force is removed, thereby allowing pathway (<NUM>) to return to its original cross-sectional size. As will be described in greater detail below, spring clips (<NUM>) are dimensioned to fit within respective slots (<NUM>) of seal housing (<NUM>) in order to promote the coupling of obturator (<NUM>) with cannula assembly (<NUM>) via friction fitting.

<FIG> show an exemplary use of obturator (<NUM>) and cannula assembly (<NUM>) as a trocar (<NUM>) to access the abdominal cavity of a patent (<NUM>) through the patient abdominal wall (<NUM>). In particular, <FIG> show an exemplary coupling of obturator (<NUM>) with cannula assembly (<NUM>), while <FIG> show an exemplary use of the assembled trocar (<NUM>) and eventual decoupling of obturator (<NUM>) from cannula assembly (<NUM>).

<FIG> shows elongate shaft (<NUM>) inserted within working channel (<NUM>) of cannula assembly (<NUM>) such that tapered shaft surface (<NUM>) is proximal relative to slanted upper surface (<NUM>) of seal housing (<NUM>). Additionally, spring clips (<NUM>) are proximal relative to slots (<NUM>), but suitably aligned with slots (<NUM>) for coupling purposes. At the moment shown in <FIG>, obturator (<NUM>) is not suitably coupled with cannula assembly (<NUM>).

Next, as shown in <FIG>, the clinician may further actuate obturator head (<NUM>) and cannula assembly (<NUM>) toward each other such that tapered shaft surface (<NUM>) engages with slanted upper surface (<NUM>) of seal housing (<NUM>), and such that spring clips (<NUM>) are driven into their respective slots (<NUM>). Engagement between tapered shaft surface (<NUM>) and slanted surface (<NUM>), as well as retention of spring clips (<NUM>) within respective slots (<NUM>), may help promote an interference fit coupling between obturator (<NUM>) and cannula assembly (<NUM>) in order to form trocar (<NUM>).

In some instances, engagement between tapered shaft surface (<NUM>) and slanted surface (<NUM>) may cause deformation of tapered shaft surface (<NUM>) and/or slanted surface (<NUM>). Additionally, in some instances, engagement between spring clips (<NUM>) and the portion of seal housing (<NUM>) defining slots (<NUM>) may cause deformation of spring clips (<NUM>) and/or the portion of seal housing (<NUM>) defining slots (<NUM>). Such deformation may further promote the interference fit coupling between obturator (<NUM>) and cannular assembly (<NUM>).

Tapered shaft surface (<NUM>) and slanted upper surface (<NUM>) of seal housing (<NUM>) may have complementary surfaces, such that when the clinician actuates obturator head (<NUM>) and cannula assembly (<NUM>) toward each other, engagement between tapered shaft surface (<NUM>) and slanted upper surface (<NUM>) promotes a frictional braking force that may prevent obturator head (<NUM>) from actuating any further relative to cannula assembly (<NUM>) in the distal direction. The frictional braking force generated between surfaces (<NUM>, <NUM>) by actuating of obturator head (<NUM>) and cannula assembly (<NUM>) toward each other may create a suitable interference fit coupling between surfaces (<NUM>, <NUM>) strong enough to suitably prevent accidental decoupling of obturator (<NUM>) and cannula assembly (<NUM>) during exemplary use in accordance with the description herein. In other words, the frictional engagement between surfaces (<NUM>, <NUM>) may help suitably prevent obturator (<NUM>) from proximally decoupling with cannula assembly (<NUM>). For instance, the friction engagement between surfaces (<NUM>, <NUM>) may be strong enough to keep trocar (<NUM>) assembled while the clinician grabs trocar (<NUM>) solely by obturator head (<NUM>).

It should be understood that slanted upper surface (<NUM>) and tapered shaft surface (<NUM>) engage each other along a plane such that a the frictional resistance to motion between surfaces (<NUM>, <NUM>) has at least a partial component that extends along the mating path between obturator (<NUM>) and cannula assembly (<NUM>). The partial component of frictional resistance to motion between surfaces (<NUM>, <NUM>) may be sufficiently strong enough to prevent obturator (<NUM>) from proximally decoupling with cannula assembly (<NUM>).

Slots (<NUM>) of seal housing (<NUM>) are defined by an outer lip (<NUM>) and slanted upper surface (<NUM>). Slots (<NUM>) are dimensioned narrower compared to the widest portion of spring clips (<NUM>). Therefore, when the clinician actuates obturator head (<NUM>) and cannula assembly (<NUM>) toward each other, spring clips (<NUM>) make contact with the portions of seal housing (<NUM>) defining slots (<NUM>). Such contact may drive legs (<NUM>) and opposite sides of central portion (<NUM>) to flex inwardly relative to each other, thereby altering the cross-sectional size of pathway (<NUM>). The contact between the portion of seal housing (<NUM>) defining slots (<NUM>) and spring clips (<NUM>) that causes spring clip (<NUM>) to flex inwards may generate a sufficient frictional braking force strong enough to suitably prevent accidental decoupling of obturator (<NUM>) and cannula assembly (<NUM>) during exemplary use in accordance with the description herein. For instance, the friction engagement between slots (<NUM>) and spring clips (<NUM>) may be strong enough to keep trocar (<NUM>) assembled while the clinician grabs trocar (<NUM>) solely by obturator head (<NUM>).

It should be understood that spring clips (<NUM>) and slots (<NUM>) engage each other along a plane such that the frictional resistance to motion between surfaces of spring clips (<NUM>) and slots (<NUM>) has at least a partial component that extends along the mating path between obturator (<NUM>) and cannula assembly (<NUM>). The partial component of frictional resistance to motion between surfaces of spring clips (<NUM>) and slots (<NUM>) may be sufficiently strong enough to prevent obturator (<NUM>) from proximally decoupling with cannula assembly (<NUM>).

Additionally, central portion (<NUM>) may initially deform while being inserted into slots (<NUM>), and then extend distally within slots (<NUM>) far enough to no longer make contact with portions of seal housing (<NUM>) defining slots (<NUM>). In such an instance, the resilient nature of spring clips (<NUM>) may allow central portion (<NUM>) to return toward its initial shape such that the widest portion of central portion (<NUM>) is wider than slots (<NUM>). Therefore, contact between central portion (<NUM>) and the portion of seal housing (<NUM>) defining slots (<NUM>) may further prevent accidental decoupling of obturator (<NUM>) with cannula assembly (<NUM>) during exemplary use.

In some instances not defined by the wording of the appended claims, spring clips (<NUM>) may not be resilient at all. In such instances, spring clips (<NUM>) may be more like downwardly extending pins that create a frictional force with slots (<NUM>) in a similar manner as tapered shaft surface (<NUM>) and slanted upper surface (<NUM>) described above.

With obturator (<NUM>) suitably coupled with cannula assembly (<NUM>) to form trocar (<NUM>), the clinician may proceed to use trocar (<NUM>) to access the abdominal cavity of a patient (<NUM>) through the patient abdominal wall (<NUM>). As best shown in <FIG>, with obturator (<NUM>) received within cannula assembly (<NUM>) and connected to seal housing (<NUM>), a clinician manipulates trocar (<NUM>) via obturator head (<NUM>) and seal housing (<NUM>) to urge obturator tip (<NUM>) against skin (<NUM>) and inward toward abdominal cavity (<NUM>) while rotating trocar (<NUM>) back and forth. It should be understood that as the clinician manipulates trocar (<NUM>) inward toward abdominal cavity (<NUM>), springs clips (<NUM>) and tapered shaft surface (<NUM>) may be further actuated into engagement cannula assembly (<NUM>). Therefore, while obturator tip (<NUM>) is urged into abdominal cavity (<NUM>), the chances of the clinician overcoming the friction fitting between obturator (<NUM>) and cannula assembly (<NUM>), thereby inadvertently decoupling trocar (<NUM>), is reduced. Continued inward urging of trocar (<NUM>) further directs obturator tip (<NUM>) and cannula tip (<NUM>) distally through the layers of fat (<NUM>) and fascia (<NUM>) and into cavity (<NUM>), as shown in <FIG>.

Next, as shown in <FIG>, the clinician may pull obturator (<NUM>) proximally relative to cannula assembly (<NUM>) in order to decouple obturator (<NUM>) from cannula (<NUM>). In some instance, the clinician may hold cannula assembly (<NUM>) with one hand, while pulling obturator (<NUM>) with the other in order to overcome the friction fitting while keeping cannula assembly (<NUM>) suitably stationary within the abdominal cavity (<NUM>) of the patient. In other instances, the clinician may not have to hold cannula assembly (<NUM>) with one hand, such that the clinician may decuple obturator (<NUM>) from cannula assembly (<NUM>) by just pulling obturator (<NUM>).

The clinician may proximally actuate obturator (<NUM>) relative to cannula assembly (<NUM>) with sufficient force in order to overcome the frictional fitting between slanted upper surface (<NUM>) and tapered shaft surface (<NUM>). Additionally, the clinician may proximally actuate obturator (<NUM>) relative to cannula assembly (<NUM>) in order to overcome the frictional fitting between spring slips (<NUM>) and the surfaces of seal housing (<NUM>) defining slots (<NUM>). In instances where central portion (<NUM>) extends distally within slots (<NUM>) far enough to no longer make contact with portions of seal housing (<NUM>) defining slots (<NUM>), the clinician may proximally actuate obturator (<NUM>) relative to cannula assembly (<NUM>) with enough force to deform central portion (<NUM>) in order for central portion (<NUM>) to proximally actuate out of slots (<NUM>). After exemplary use, a user may suitably sterilize obturator (<NUM>) for another use.

Since spring clips (<NUM>) are configured to flex in response to longitudinal motion between cannula assembly (<NUM>) and obturator (<NUM>), the clinician is no longer required to provide a sufficient depression force (e.g. a pinching motion) to decouple obturator (<NUM>) from cannula assembly (<NUM>). Therefore, spring clips (<NUM>) may have an aspect ratio that includes a smaller length to thickness compared to latch arms (<NUM>). Additionally, spring clips (<NUM>) may be formed of a more robust material compared to latch arms (<NUM>) described above. Due to the smaller length to thickness ratio and the more robust material, spring clips (<NUM>) may be less vulnerable to damage during the sterilization process and/or in response to accidental contact.

Additionally, since spring clips (<NUM>) no longer require lateral motion in response to a sufficient depression force applied to buttons on domed upped body (<NUM>), base plate (<NUM>) requires no reinforcement slots and domed upper body (<NUM>) requires no apertures. Therefore, base plate (<NUM>) may be a solid plate such that the interior defined by base plate (<NUM>) and domed upper body (<NUM>) may be sealed from exterior fluid and matter. The lack of slots and apertures may help prevent outside fluid and other matter from entering into the interior of obturator head (<NUM>), which may in turn make it easier to clean and sterilize obturator (<NUM>) compared to obturator (<NUM>) described above.

In the current example, the proximal end of both legs (<NUM>) are fixed to the distal surface of base plate (<NUM>). However, in some instances, only one leg (<NUM>) may be fixed to the distal surface of base plate (<NUM>). While in the current example, central portion (<NUM>) forms a semi-cylindrical shape, any suitable shape may be used as would be apparent to one skilled in the art in view of the teachings herein. In the current example, legs (<NUM>) terminate into central portion (<NUM>) such that legs (<NUM>) are not coupled to each other. However, this is merely optional, as legs (<NUM>) may taper toward, and directly couple with each other such that central portion (<NUM>) is omitted entirely. In the current example, legs (<NUM>) are formed of a substantially planar surface. However, this is merely option, as surfaces of legs (<NUM>) may have any suitable geometry as would be apparent to one skilled in the art in view of the teachings herein, such as an undulating surface.

While in the current example obturator (<NUM>) is used in conjunction with cannula assembly (<NUM>) to form trocar (<NUM>), it should be understood that obturator (<NUM>) may be configured to be used with cannula assembly (<NUM>) described above such that friction coupling assembly (<NUM>) suitably mates with seal assembly (<NUM>) described above.

<FIG> shows another exemplary obturator (<NUM>) that may be used in replacement of obturator (<NUM>) described above. Obturator (<NUM>) is substantially similar to obturator (<NUM>) described above, with differences elaborated below. Obturator (<NUM>) includes a proximal head (<NUM>), an elongate cylindrical shaft (<NUM>) extending distally from proximal head (<NUM>), and a tapered distal tip (not shown); which are substantially similar to proximal head (<NUM>), elongate cylindrical shaft (<NUM>), and tapered distal tip (<NUM>) described above.

Obturator head (<NUM>) includes a domed upper body (<NUM>), a base plate (<NUM>), and a interference fit coupling assembly (<NUM>), which are substantially similar to domed upper body (<NUM>), base plate (<NUM>), and interference fit coupling assembly (<NUM>) described above, except interference fitting coupling assembly (<NUM>) only includes spring clips (<NUM>) and does not include a tapered shaft surface similar to surface (<NUM>) of obturator (<NUM>). Spring clips (<NUM>) are substantially similar to spring clips (<NUM>) described above. Therefore, spring clips (<NUM>) are dimensioned to fit within respective slots (<NUM>) of seal housing (<NUM>) in order to promote the coupling of obturator (<NUM>) with cannula assembly (<NUM>) via friction fitting.

<FIG> shows another exemplary obturator (<NUM>) not defined by the wording of the appended claims, that may be used in replacement of obturator (<NUM>) described above. Obturator (<NUM>) is substantially similar to obturator (<NUM>) described above, with differences elaborated below. Obturator (<NUM>) includes a proximal head (<NUM>), an elongate cylindrical shaft (<NUM>) extending distally from proximal head (<NUM>), and a tapered distal tip (not shown); which are substantially similar to proximal head (<NUM>), elongate cylindrical shaft (<NUM>), and tapered distal tip (<NUM>) described above.

Obturator head (<NUM>) includes a domed upper body (<NUM>), a base plate (<NUM>), and an interference fit coupling assembly (<NUM>), which are substantially similar to domed upper body (<NUM>), base plate (<NUM>), and interference fit coupling assembly (<NUM>) described above, except interference fitting coupling assembly (<NUM>) only includes tapered shaft surface (<NUM>) and does not include spring clips similar to spring clips (<NUM>, <NUM>) of obturators (<NUM>, <NUM>). Tapered shaft surface (<NUM>) is substantially similar to tapered shaft surface (<NUM>) described above. Therefore, tapered shaft surface (<NUM>) is dimensioned to abut against a slanted upper surface (<NUM>) of seal housing (<NUM>) defining working channel (<NUM>) in order to promote the coupling of obturator (<NUM>) with cannula assembly (<NUM>) via friction fitting.

Such modifications may fall within the scope of the invention, which is as defined by the appended claims.

Similarly, those of ordinary skill in the art will recognize that various teachings herein may be readily combined with various teachings of any of the following: <CIT>; <CIT>; <CIT>; <CIT>; and/or <CIT>.

Claim 1:
A surgical access device comprising:
(a) a cannula assembly (<NUM>, <NUM>) including:
(i) a cannula (<NUM>, <NUM>),
(ii) a cannula head (<NUM>, <NUM>) coupled with a proximal end of the cannula, and
(iii) a working channel (<NUM>, <NUM>) at least partially defined by the cannula and the cannula head extending longitudinally along a central axis (A) of the cannula assembly, wherein the working channel is configured to receive a surgical instrument therethrough to access to a surgical site within a body cavity of a patient, wherein the canula head comprises a seal assembly (<NUM>, <NUM>) defining a slot (<NUM>, <NUM>) located adjacent to the working channel; and
(b) an obturator (<NUM>), wherein the obturator is configured to removably couple with the cannula assembly along the central axis to facilitate insertion of the surgical access device through a body wall of the patient, wherein the obturator comprises:
(i) an elongated shaft (<NUM>) extending along a longitudinal axis, wherein the elongated shaft is dimensioned to fit within the working channel of the cannula assembly,
(ii) a tapered distal tip (<NUM>) located at a distal portion of the elongated shaft, and
(iii) an obturator head (<NUM>) located at a proximal portion of the elongated shaft, wherein the obturator head comprises an interference fit feature (<NUM>, <NUM>, <NUM>) configured to inhibit proximal movement between the obturator and the cannula assembly via a frictional force against a surface of the cannula assembly, wherein the interference fit feature comprises a downwardly extending pin coupled to the base plate, wherein the downwardly extending pin is configured to engage a portion of the seal assembly defining the slot to generate at least a portion of the friction force, wherein the downwardly extending pin comprises a spring clip formed from a resilient material.