Patent Description:
The documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT> were cited. Particularly, <CIT> discloses a system with an obturator and a working tube; wherein the obturator includes an upper control housing and a pair of spreading legs.

Diagnosis and treatment of conditions affecting the brain are among the most difficult and complex problems that face the medical profession. The brain is a complex and delicate soft multi-component tissue structure that controls bodily functions through a complex neural network connected to the rest of the body through the spinal cord. The brain and spinal cord are contained within and protected by significant bony structures, e.g., the skull and the spine. Given the difficulty of accessing the brain through the hard bony protective skull and the delicate network and complex interactions that form the neural communication network contained within the brain that define the human body's ability to carry on its functions of speech, sight, hearing, functional mobility, reasoning, emotions, respiration and other metabolic functions, the diagnosis and treatment of brain disorders presents unique challenges not encountered elsewhere in the body.

For example, abnormalities such as intracranial cerebral hematomas (ICH), abscesses, Glioblastomas (GB) and metastases (mets) manifest themselves in the intraparenchymal subcortical space (i.e., the white matter) of the brain are particularly challenging to access, let alone treat. The white matter and cortex of the brain contain eloquent communication structures (neural network) which are located in the cortical and subcortical space, called fiber tracts and fascicles. Thus, traditionally, unless the ICH, GB, and/or mets where considered anything but "superficial," such conditions have been considered inoperable, simply because getting to the abnormality ICH, GB and/or mets are considered just as damaging as letting the condition take its course. Similarly, tissue abnormalities such as tumors, cysts and fibrous membrane growths which manifest within the intraventricular space of the brain are considered challenging to safely access and often inoperable, due to their locations within the brain.

To assist in diagnosis and subsequent treatment of brain disorders, clear, accurate imaging of brain tissue through the skull is required. In recent years significant advances have been made in imaging technology, including stereotactic X-ray imaging, Computerized Axial Tomography (CAT), Computerized Tomographic Angiography (CTA), Position Emission Tomography (PET) and Magnetic Resonance Imaging (MRI), Diffusion Tensor Imaging (DTI) and Navigation systems (instrument position tracking systems). These imaging devices and techniques permit the surgeon to observe conditions within the brain in a non-invasive manner without opening the skull, as well as provide a map of critical structures surrounding an area of interest, including structures such as blood vessels, membranes, tumor margins, cranial nerves, including fiber tracts and fascicles. If an abnormality is identified through the use of one or more imaging modalities and/or techniques, it may be necessary or desirable to surgically intervene.

Once a course of action has been determined based upon one or more imaging techniques, a surgical treatment may be necessary or desired. To operate surgically within the brain, access must be obtained through the skull and delicate and eloquent brain tissue such as blood vessels, the lymphatic system and nerves overlying and surrounding the abnormality that can be adversely affected by slight disturbances and disruptions. Therefore, great care must be taken in operating on the brain so as not to disturb these eloquent tissues to prevent adverse consequences resulting from an intervention.

Traditionally, accessing abnormalities which manifest in deeper spaces within the brain has meant a need for a surgery that creates a disruptive invasive approach. In some instances, in order to obtain access to target tissue, a substantial portion of the skull is removed and entire sections of the overlying brain are retracted to obtain access. For example, surgical brain retractors are used to pull apart or spread delicate brain tissue, which can produce transient and/or permanent deficits. In some instances, a complication known as "retraction injury" may occur due to use of brain retractors. Of course, such techniques are not appropriate for all situations, and not all patients are able to tolerate and recover from such invasive techniques.

It is also known to access certain portions of the brain by creating a burr hole craniotomy, but only limited surgical techniques may be performed through such smaller openings. In addition, some techniques have been developed to enter through the nasal passages, opening an access hole through the bone to remove skull-based tumors, for example, in the area of the pituitary. These approaches are referred to as Expanded Endonasal Approaches (EEA).

A significant advance in brain surgery is stereotactic surgery involving a stereotactic frame correlated to stereotactic X-ray images and MRI to guide a navigational system probe or other surgical instrument through an opening formed in the skull through brain tissue to a target lesion or other body. A related advance is frameless image guidance, in which an image of the surgical instrument is superimposed on a pre-operative image to demonstrate the location of the instrument to the surgeon and trajectory of further movement of the probe or instrument.

It is known to access certain portions of the brain with surgical access systems. An example of a surgical access systems used to access certain portions of the brain may be found in <CIT>. A navigation member may be used with an obturator by slidingly engaging with the obturator.

One issue with surgical access systems that arises is compatibility a variety of known navigational arrangements and systems. For example, some navigational system probes may be incompatible because they are sized differently, and therefore unable to engage with an existing obturator directly. More specifically, certain navigational system probes may be too wide and therefore unable to be seated within an obturator without alterations being made to the obturator. Alternatively, a navigational system probe may be too narrow and may not be able to be properly seated within an obturator. Additionally, incompatibility may occur due to the material from which the obturator is constructed which can interfere or block the signals produced by the navigational systems, especially those navigational system that utilize electromagnetic signals (an example of which is the AxiEM System manufactured by Medtronic). Notwithstanding the foregoing advances in surgical navigation, there remains a need for improved surgical techniques and apparatuses for operating on brain tissue, including providing multi-compatible navigational systems.

The invention is defined by independent claim <NUM>, with further embodiments defined by the dependent claims. Implementations of the disclosure may include one or more of the following optional features.

One aspect of the disclosure provides an adapter for use with a surgical access assembly. The adapter comprises an adapter body and a positioning member. The adapter body is defined by a distal end and a proximal end opposite the distal end. The positioning member extends from the distal end of the adapter body. A channel extends through the adapter body, extending from the proximal end and toward the distal end.

In one exemplary arrangement, the adapter body further comprises a locking mechanism to secure a navigation element to the adapter against movement.

In one exemplary arrangement, the channel terminates in a closed distal end that defines a seating portion. The distal end tapers inwardly to define the seating portion. A window may be provided to provide visual access to the channel, adjacent the seating portion.

In one exemplary arrangement, the adapter body further includes a grip portion disposed adjacent to the proximal end of the adapter body.

In one exemplary arrangement, the adapter body includes an engagement section that includes an annular angled surface encircling the proximal end of the positioning member.

Another aspect of the disclosure provides an adapter for a surgical access assembly comprising a first adapter casing, a second adapter casing and a mounting piece. The first and second adapter casings are selectively engageable with one another. The first and second adapter casings cooperate to define a channel that is configured to receive a navigation element. The mounting piece is selectively engaged with the first and second adapter casings.

In one exemplary arrangement, the first adapter casing includes a first navigation groove defined between a proximal end of the first adapter casing and a distal end of the first adapter casing, and the second adapter casing includes a second navigation groove defined between a proximal end of the second adapter casing and a distal end of the second adapter casing, the first and second navigation grooves collectively define the channel.

In one exemplary arrangement, a portion of the mounting piece is disposed within a portion of an inner surface of the first adapter casing and a portion of an inner surface of the second adapter casing to secure the mounting piece to the first and second adapter casings.

In one exemplary arrangement, the first adapter casing includes an engagement channel adjacent to the distal end of the first adapter casing, the second adapter casing includes an engagement channel adjacent to the distal end of the second adapter casing, and the mounting piece includes a securing portion that engages with the engagement channel of the first adapter casing and the engagement channel of the second adapter casing.

In one exemplary arrangement, an engagement surface of the first adapter casing defines one or more first cooperating members, and wherein an engagement surface of the second adapter casing includes one or more second cooperating members configured to engage with the one or more first cooperating members of the inner surface of the first adapter casing to connect the first and second adapter casings together.

In one exemplary arrangement, the mounting piece further includes a window. The window may further include a spring element that is biased inwardly toward the channel.

In one exemplary arrangement, the first and second adapter casings are hingedly connected to the mounting portion.

The drawings described herein are for illustrative purposes only of selected configurations and not all possible implementations, and are not intended to limit the scope of the present disclosure. <FIG> show embodiments according to the invention. The rest of the figures are not according to the invention but are considered useful for its understanding.

Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed assemblies are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.

Described herein is an adapter for a surgical access assembly and various components for use in same. The components disclosed herein provide surgeons with an enhanced ability to minimize trauma to the patient, while providing efficient improved minimally invasive surgical techniques, such as, for example, during intracranial surgical techniques.

Referring to <FIG> a perspective view of a medical access assembly <NUM> including a navigation adapter <NUM> mounted to an obturator <NUM> of a surgical access system is shown. A navigational element <NUM> is selectively engageable with adapter <NUM> to be used with obturator <NUM> of a surgical access system. In use, the obturator <NUM> is selectively slidably engaged with an outer sheath (not shown) to provide access to an area of interest in a patient. An example of an exemplary surgical access system may be found in <CIT>. In one exemplary arrangement, the navigational element <NUM> (best seen in <FIG>) is defined by a proximal end <NUM>, a body portion <NUM> and a distal end <NUM>. When navigational element <NUM> is positioned within adapter <NUM>, the body portion <NUM> will extend along an axis A- A and beyond an adapter proximal end <NUM>. By having the proximal end <NUM> extend proximally from the adapter proximal end <NUM>, the navigational element <NUM> is able to selectively connect to a navigation system (not shown). In some implementations, navigational element <NUM> is a navigation probe having a tapered distal tip <NUM>. In addition, navigational element <NUM> may include an annular notch <NUM>, which may receive a sealing element such as an O-ring (not shown).

When navigational element <NUM> is assembled with adapter <NUM>, body portion <NUM> extends about axis A-A. As will be discussed in greater detail below, adapter <NUM> enables navigational element <NUM> to be used with obturator <NUM>, even if navigational element <NUM> is incompatible or unable to operationally engage with obturator <NUM>. As will be explained in further detail below, an offset X between a proximal end face <NUM> and a distal tip <NUM> of the obturator <NUM> is a known parameter. As the adapter <NUM> is configured to locate the distal end <NUM> of the navigational element <NUM> in the same plane as the proximal end face <NUM> of the obturator <NUM>, a navigation system can calculate the location of the distal tip <NUM> of the obturator <NUM> by factoring in the known offset X with the location of the distal end <NUM>.

Referring now to <FIG>, details of the adapter <NUM> will be described in further detail. Adapter <NUM> is defined by an adapter body <NUM> and a positioning member <NUM>. The adapter body <NUM> is further defined by proximal end <NUM> and distal end <NUM>. In one exemplary arrangement, a handle portion <NUM> is disposed at the proximal end <NUM>. The positioning member <NUM> extends from the distal end <NUM> of the adapter body <NUM> and generally along an axis B-B. The positioning member <NUM> is defined by a length L (<FIG>) and further includes a tip member <NUM>. In one exemplary arrangement, the tip member <NUM> is configured to narrow from a body section <NUM> of the positioning member <NUM> to an adapter distal tip <NUM>. Other tip member <NUM> configurations are also contemplated such as a rounded distal tip. In some implementations, the adapter body <NUM> and positioning member <NUM> are molded together as a unitary body. In other implementations, adapter body <NUM> and positioning member <NUM> are in selective engagement with each other. Handle portion <NUM> may be further defined by grip portions <NUM> that extends outwardly from axis B-B. In one exemplary arrangement, grip portion <NUM> is configured to be generally perpendicular to axis B-B. In some implementations, Adapter <NUM> may further include a locking mechanism <NUM>, which will be described in more detail below. Though <FIG> depict locking mechanism <NUM> disposed on grip portion <NUM>, it should be noted that locking mechanism <NUM> may be disposed anywhere on handle portion <NUM>.

As best seen in <FIG> adapter body <NUM> further includes an engagement section <NUM> disposed distal to handle portion <NUM>. As best seen in <FIG> and <FIG>, engagement section <NUM> includes an annular angled surface <NUM> that encircles a proximal end <NUM> of positioning member <NUM>. Angled surface <NUM> is configured to frictionally engage an annular chamfer <NUM> disposed about a proximal opening <NUM> formed in a top surface <NUM> of obturator <NUM> (see <FIG>and <FIG>). Angled surface <NUM> is angled inwardly toward a central axis of the positioning member <NUM>.

The handle portion <NUM> may include an arcuate section <NUM> disposed between proximal end <NUM> and engagement section <NUM>. Arcuate portion <NUM> may advantageously allow a physician to comfortably hold adapter <NUM>, reducing physician fatigue and making adapter <NUM> easier to manipulate in the surgical field.

With continued reference to <FIG>, handle portion <NUM> includes an axial channel <NUM>. Channel <NUM> extends from an opening <NUM> disposed at proximal end <NUM>, along axis B-B, but terminates proximally of the positioning member <NUM>. An inwardly extending chamfer <NUM> may be disposed around opening <NUM> to assist in directing navigational element <NUM> within channel <NUM>. Channel <NUM> is sized to receive navigational element <NUM> therewithin. It is contemplated that various adapters <NUM> may be provided with channels <NUM> being sized with predetermined diameters that permit known sized navigational elements <NUM> to be inserted therein. Alternatively, for those arrangements where the diameter of the channel <NUM> is significantly larger than the diameter of the navigational element <NUM>, an optional sizing sleeve (not shown) may be provided that has an outside diameter that is receivable within the channel <NUM>, and has an inside diameter that receives the navigational element <NUM> snugly. As a further option, navigational member <NUM> may be provided with the annular notch <NUM> formed on an outside surface of the body portion <NUM>, the annular notch <NUM> receiving an o-ring or a spring clip therein to frictionally retain the navigational element <NUM> within the channel <NUM>.

Disposed at a distal end <NUM> of channel <NUM> is a seating portion <NUM>. In one exemplary arrangement, seating portion <NUM> is defined by an annular inwardly directing surface <NUM>. The inwardly directing surface <NUM> serves to self-direct and center navigational element <NUM> when inserted within adapter <NUM>. Other configurations of seating portion <NUM> are also contemplated, such as tongue and groove arrangements.

Handle portion <NUM> may also define at least one window <NUM>. Window <NUM> allows a user to visually confirm the placement of navigational element <NUM> (<FIG>) when disposed within adapter <NUM>. Windows <NUM> also serve to reduce the weight of adapter <NUM>, thereby making adapter <NUM> easier to manipulate in the surgical field. Reducing the weight of adapter <NUM> also reduces physician fatigue during a surgical procedure.

In the exemplary arrangement, at least one window 128a may be disposed adjacent to positioning member <NUM>, enabling a user to visually confirm that a navigational element <NUM> is in proper contact with seating portion <NUM>. As depicted in <FIG>, window 128a may be a front- facing window, such that the "front" of the adapter <NUM> is, with respect to the width of grip portion <NUM>, being at its widest. Additionally or alternatively, in an exemplary arrangement, a window 128b may be positioned adjacent to grip portion <NUM> to visually confirm that the navigational element <NUM> is disposed along the axis B-B. As depicted in <FIG>, window 128b may be a side-facing window, such that the "side" of the adapter is with respect to the width of grip portion <NUM> being at its narrowest. Adapter <NUM> having both a front-facing window 128a and a side-facing window 128b may be advantageous in allowing a user to ensure proper placement of navigational element <NUM> (<FIG>) by viewing navigational element <NUM> from two different angles. In some implementations, at least a portion of adapter <NUM> may be made of a transparent material, which also allows a user to visually confirm the placement of navigational element <NUM> when inside adapter <NUM>.

Referring to <FIG>, in some implementations, locking mechanism <NUM> of adapter <NUM> may operatively fix navigational element <NUM> (<FIG>) to adapter <NUM>. More specifically, in one exemplary arrangement, grip portion <NUM> (or other portion of adapter <NUM>) is provided with a receiving aperture <NUM> that is configured to receive a locking member <NUM>. In one exemplary arrangement, receiving aperture <NUM> is threaded. Receiving aperture <NUM> is in communication with channel <NUM>. A retaining channel <NUM> extends generally perpendicular to the receiving aperture <NUM>. The locking member <NUM> includes a reduced diameter section <NUM>. After locking member <NUM> is at least partially engaged within receiving aperture <NUM>, a retaining member <NUM> is positioned within retaining channel <NUM> so as to be disposed adjacent to the reduced diameter section <NUM>. In operation, once the retaining member <NUM> is inserted within the retaining aperture <NUM>, an actuating member <NUM> is rotated to move the retaining member <NUM> toward the channel <NUM> and into engagement with the navigational element <NUM>, thereby locking the navigational element <NUM> within the adapter <NUM>. The retaining member <NUM> prevents locking mechanism <NUM> from being completely disengaged from adapter <NUM> and entering the surgical field and, particularly, it prevents locking mechanism <NUM> from contacting exposed body tissue in the surgical field.

As shown in <FIG>, obturator <NUM> may also be provided with a locking mechanism <NUM> that is similar to locking mechanism <NUM>.

In operation, the navigational element <NUM> is inserted through opening <NUM> and into channel <NUM> until a distal tip <NUM> engages seating portion <NUM>. A user may view the navigational element <NUM> while in the actuator <NUM> by looking through windows <NUM>. Once proper positioning is confirmed, if available, locking mechanism <NUM> is activated to secure navigational element <NUM> in place within the actuator <NUM>.

Once navigational element <NUM> is secured to the actuator <NUM>, the adapter <NUM> is joined to the obturator <NUM>. More specifically, the positioning member <NUM> is inserted within the proximal opening <NUM> of the obturator <NUM>. As the positioning member <NUM> is elongated, a portion of the positioning member <NUM> will be disposed within the obturator <NUM>, extending proximally from the top surface of the obturator <NUM>, as shown in <FIG>. The annular angled surface <NUM> of the engagement section <NUM> engages the annular chamfer <NUM> in a complementary manner. Once positioned, locking mechanism <NUM> may be actuated to lock the positioning member <NUM> to the obturator <NUM>. As discussed above, once so assembled, the seating portion <NUM> serves to position the distal tip <NUM> of the navigational element <NUM> in alignment with the top surface <NUM> of the obturator <NUM>. The proximal end <NUM> of the navigational element <NUM> is secured to the navigational system. Thus, when the obturator <NUM> is assembled to the outer sheath of a surgical access assembly, because the offset X between the top surface <NUM> and the distal tip <NUM> of the obturator <NUM> is a known predefined length, the location of the distal tip <NUM> may be determined while the surgical access assembly is in use, as the distal tip <NUM> of the navigational element <NUM> will be known by correlating the offset X with the location of the distal tip <NUM> of the navigational element <NUM>.

Referring now to <FIG>, a perspective view of a medical access assembly <NUM> including an alternative adapter <NUM> mounted to an obturator <NUM> of a surgical access assembly is shown. Similar to adapter <NUM>, adapter <NUM> is configured to selectively engage with obturator <NUM> of a surgical access system to allow different sized navigational elements <NUM> to be used with obturator <NUM>. According to the invention, adapter <NUM> comprises a first adapter casing <NUM>, a second adapter casing <NUM>, and a mounting piece <NUM>. First and second adapter casings <NUM>, <NUM> are each defined by a proximal end <NUM> and a distal end <NUM>. In some implementations, at least one of first adapter casing <NUM>, second adapter casing <NUM>, and mounting piece <NUM> may include locking mechanism <NUM> (best seen in <FIG>).

Referring now to <FIG>, first adapter casing <NUM> extends partially about an axis D-D and is defined by a proximal end 210a and a distal end 212a. In one exemplary arrangement, first adapter casing <NUM> has a generally U-shaped cross-section. First adapter casing <NUM> includes a navigational channel 214a defined between proximal end 210a and distal end 212a on an inner surface 222a of first adapter casing <NUM>.

First adapter casing <NUM> may include at least one first cooperating member <NUM> disposed on at least one engaging surface 226a of first adapter casing <NUM>. In one exemplary configuration, the at least one first cooperating member <NUM> may be configured as a detent and have a thickened end <NUM>. As depicted in <FIG>, in one exemplary arrangement, the first adapter casing <NUM> has two first cooperating members <NUM> disposed adjacent to proximal end 210a of first adapter casing <NUM>, and two first cooperating members <NUM> disposed adjacent to distal end 212a of first adapter casing <NUM>, disposed on opposite sides of channel 214a. It should be noted, however, that the at least one first cooperating member <NUM> may be located anywhere on the at least one engaging surface 226a.

First adapter casing <NUM> also includes a mechanism for connecting mounting piece <NUM> to first adapter casing <NUM>. In one exemplary arrangement (as depicted in <FIG>), an engagement channel 228a disposed adjacent to distal end 212a. Engagement channel 228a extends inwardly from inner surface 222a of first adapter casing <NUM>. As will be explained in further detail below, engagement channel 228a cooperates with a securing portion <NUM> of mounting piece <NUM> to secure mounting piece <NUM> to first and second adapter casings <NUM>, <NUM>.

With continued reference to <FIG>, second adapter casing <NUM> extends partially about an axis E-E and is defined by a proximal end 210b and a distal end 212b. In one exemplary configuration, the second adapter casing <NUM> has a generally U-shaped cross-section. Second adapter casing <NUM> includes a navigational groove 214b defined between proximal end 210b and distal end 212a on an inner surface 222b of second adapter casing <NUM>. In one exemplary arrangement, second adapter casing <NUM> is generally a mirror image of first adapter casing <NUM>.

Second adapter casing <NUM> may include at least one second cooperating member <NUM> disposed on at least one engaging surface 226b of second adapter casing <NUM>. The at least one second cooperating member <NUM> may be an indentation configured to permit engagement with a first cooperating member <NUM> in a complementary manner. In addition, an engagement tab <NUM> may be disposed within the indentations of second cooperating member <NUM> adjacent to an edge of the indentation of second cooperating member <NUM>. With this arrangement, the thickened end of the first cooperating member <NUM> may snap-fit around the engagement tab <NUM> to assist in locking the first and second adapter casings <NUM> and <NUM> together. As depicted in <FIG>, the second adapter casing <NUM> has two second cooperating members <NUM> disposed adjacent to proximal end 210b of second adapter casing <NUM>, and two second cooperating members <NUM> disposed adjacent to distal end 212b of second adapter casing <NUM>, disposed on either side of the navigation groove 214b, generally corresponding to the locations of the first cooperating members <NUM> of first adapter casing 204a. It should be noted, however, that the at least one second cooperating member <NUM> may be located anywhere on the at least one engaging surface 226b.

It should also be noted that, though <FIG> depicts first adapter casing <NUM> including four first cooperating members <NUM>, and second adapter casing <NUM> including four second cooperating members <NUM>, first adapter casing <NUM> may have any number of first cooperating members <NUM> greater than one, and second adapter casing <NUM> may have any number of second cooperating members <NUM> equal to or greater than the number of first cooperating members <NUM> that first adapter casing <NUM> has. Furthermore, first adapter casing <NUM> may have at least one second cooperating member <NUM> in addition to the at least one first cooperating member <NUM>. Similarly, second adapter casing <NUM> may have at least one first cooperating member <NUM> in addition to the at least one second cooperating member <NUM>. It should be noted that other engagement mechanisms may be used to secure first adapter casing <NUM> to second adapter casing <NUM>.

Second adapter casing <NUM> also includes a mechanism for connecting mounting piece <NUM> to second adapter casing <NUM>. According to the invention (as depicted in <FIG>), second adapter casing <NUM> includes engagement channel 228b disposed adjacent to distal end 212b. Engagement channel 228b extends inwardly from inner surface 222b of second adapter casing <NUM>. As with engagement channel 228a, engagement channel 228b cooperates with securing portion <NUM> of mounting piece <NUM> to secure mounting piece <NUM> to first and second adapter casings <NUM>, <NUM>. It should be noted that other engagement mechanisms may be used to secure mounting piece <NUM> to first and second adapter casings <NUM>, <NUM>.

With continued reference to <FIG>, mounting piece <NUM> is defined by a proximal end <NUM> and a distal end <NUM>, and extends about an axis E-E. Distal end <NUM> of mounting piece <NUM> includes an annular angled surface <NUM> (best seen in <FIG>). Angled surface <NUM> tapers from an outside diameter of the mounting piece <NUM> toward a positioning member <NUM> that extends from the distal end <NUM>. Similar to adapter <NUM>, angled surface <NUM> is configured to be complementary to chamfer <NUM> to seat the mounting piece <NUM> within obturator <NUM>.

Mounted to a proximal face <NUM> of the proximal end <NUM> of mounting piece <NUM> is the securing portion <NUM>. Securing portion <NUM> is configured to engage with engagement channels 228a, 228b of first and second adapter casings <NUM>, <NUM> to form assembled adapter <NUM> (<FIG>). Referring to <FIG>, securing portion <NUM> is defined by a flange member <NUM> that is spaced from the proximal face <NUM> such that an annular groove <NUM> is formed between the flange member <NUM> and proximal face <NUM>. The flange member <NUM> has a diameter that is smaller than a diameter of the mounting piece <NUM>.

A stopper portion <NUM> may extend outwardly from the flange member <NUM>. Stopper portion <NUM> may be received in a complementary key hole (not shown) formed in either of first and second adapter casings <NUM>, <NUM>, within engagement channels 228a, 228b, respectively, to prevent rotation of mounting piece <NUM> with respect to assembled first and second adapter casings <NUM>, <NUM>.

A mounting opening <NUM> is formed through the securing portion <NUM>. Mounting opening <NUM> is in communication with a mounting piece channel <NUM>. Mounting piece channel <NUM> may be constructed of a predetermined size to accommodate navigational element <NUM> (<FIG>) therein. Mounting piece channel <NUM> terminates in a closed distal end. Closed distal end may be configured to taper inwardly to define a seating portion <NUM> that receives the distal tip <NUM> of navigational element <NUM>, similar to the seating portion <NUM> described above in connection with adapter <NUM>. More specifically, similar to seating portion <NUM>, seating portion <NUM> may be annularly angled such that when navigational element <NUM> contacts seating portion <NUM>, navigational element <NUM> is properly seated within adapter <NUM> so as to be aligned with a top surface of obturator <NUM>.

To assemble adapter <NUM>, the flange member <NUM> is inserted within engagement channel 228a, 228b, with the stopper element positioned within a key hole. Simultaneously, the first and second casings <NUM>, <NUM> are brought into engagement with one another such that at least one first cooperating member <NUM> of first adapter casing <NUM> engages with the at least one second cooperating member <NUM> of second adapter casing <NUM>. This engagement may be a snap-fit arrangement that locks first and second adapter casings <NUM>, <NUM> together in a cooperating manner, thereby trapping the flange member <NUM> within the first and second casings <NUM>, <NUM>. When first adapter casing <NUM> is assembled with second adapter casing <NUM>, navigational channels 214a, 214b combine to form the navigational channel <NUM> that is in communication with mounting piece channel <NUM> (<FIG>) to form a continuous channel. The continuous channel is in communication with proximal opening <NUM> of obturator, when adapter <NUM> is assembled to obturator <NUM>.

Once assembled, navigation element <NUM> may be disposed within combined navigational channel <NUM>/mounting piece channel <NUM>, such that the distal tip <NUM> is directed into seating portion <NUM>. Once positioned, locking mechanism <NUM> may be actuated to lock the navigational element <NUM> within adapter <NUM>.

In some implementations, a window 203a may be disposed on at least one of the first and second adapter casings <NUM>, <NUM>. Window 203a may extend partially about an axis C-C between proximal end <NUM> and distal end <NUM> of assembled first and second adapter casings <NUM>, <NUM>. Alternatively or additionally, a window 203b may be disposed on mounting piece <NUM>, enabling a user to visually confirm that navigational element <NUM> is in proper contact with seating portion <NUM> (<FIG>). In some implementations, Window 203b may be offset by <NUM> degrees from window 203a. Similar to window <NUM>, windows <NUM> a, 203b may allow a user to visually confirm the placement of navigational element <NUM> when inside adapter <NUM>. Furthermore, windows 203a, 203b serve to reduce the weight of adapter <NUM>, thereby making adapter <NUM> easier to manipulate in the surgical field. Reducing the weight of adapter <NUM> also reduces physician fatigue during a surgical procedure. Adapter <NUM> having both windows 203a, 203b may be advantageous in allowing a user to ensure proper placement of navigational element <NUM> by viewing navigational element <NUM> from two different angles. In some implementations, at least a portion of at least one of first adapter casing <NUM>, second adapter casing <NUM>, and mounting piece <NUM> may be made of a transparent material, also allowing a user to visually confirm the placement of navigational element <NUM> when inside adapter <NUM>.

Once assembled, navigational channel <NUM> may extend along axis C-C and define a first diameter DI. Navigational element <NUM> may also have a second diameter D2, which is less than DI and allows navigational element <NUM> to be slidingly received within navigational channel <NUM>.

When navigational element <NUM> is positioned within adapter <NUM>, navigational element <NUM> will extend beyond proximal end <NUM> of first and second adapter casings <NUM>, <NUM> in a direction away from adapter <NUM>. This allows navigational element <NUM> to be connected to a navigational system (not shown) while navigational element <NUM> is positioned within adapter <NUM>. Furthermore, when assembled with adapter <NUM>, navigational element <NUM> extends beyond distal end proximal end <NUM> of first and second adapter casings <NUM>, <NUM> and within mounting piece <NUM>, allowing navigational element <NUM> to engage seating portion <NUM>.

Once navigational element <NUM> is secured to the actuator <NUM>, the adapter <NUM> is joined to the obturator <NUM>. More specifically, the positioning member <NUM> is inserted within the proximal opening <NUM> of the obturator <NUM>. As the positioning member <NUM> is elongated, a portion of the positioning member <NUM> will be disposed distally within the obturator <NUM>, spaced from the top surface of the obturator <NUM>, thereby providing stability of the engagement, as shown in <FIG>. The annular angled surface <NUM> of the mounting piece <NUM> engages the annular chamfer <NUM> of the obturator <NUM> in a complementary manner. Once positioned, a locking mechanism <NUM> may be actuated to lock the positioning member <NUM> to the obturator <NUM>, as described above. Further, once so assembled, the seating portion <NUM> serves to position the distal tip <NUM> of the navigational element <NUM> in alignment with the top surface <NUM> of the obturator <NUM>. The proximal end <NUM> of the navigational element <NUM> is secured to the navigational system. Thus, when the obturator <NUM> is assembled to the outer sheath <NUM> of a surgical access assembly, because the offset X between the top surface <NUM> and the distal tip <NUM> of the obturator <NUM> is a predefined length, the location of the distal tip <NUM> may be determined while the surgical access assembly is in use, as the distal tip <NUM> of the navigational element <NUM> will be known by correlating the offset X with the location of the distal tip <NUM> of the navigational element <NUM>.

Referring to <FIG>, a further alternative arrangement of an adapter <NUM> will be described. Adapter <NUM> generally includes similar elements as described in connection with adapter <NUM>, including handle <NUM>, adapter body <NUM>, positioning member <NUM> and seating portion <NUM>. Like elements from the description of adapter <NUM> have been given similar reference numbers, increased by <NUM>. Seating portion <NUM> is positioned to align with a top surface <NUM> of obturator <NUM> such that when a distal tip <NUM> is nested within seating portion <NUM>, distal tip <NUM> is aligned with top surface <NUM> of obturator <NUM>, as described above.

Much like that described above in connection with adapter <NUM>, the adapter <NUM> is configured to selectively receive the navigational element <NUM>. The navigational element <NUM> is defined by a proximal end <NUM>, a body portion <NUM> and a distal end <NUM>. The distal end <NUM> may be configured to taper inwardly from the body portion <NUM>, terminating in distal tip <NUM>. Disposed within the distal end <NUM> is an electromagnetic coil <NUM>. However, electromagnetic coil <NUM> is slightly spaced from a distal tip <NUM> of the navigational element <NUM>. Thus, as may be seen best in <FIG>, when navigational element <NUM> is seated within seating portion <NUM>, electromagnetic coil <NUM> is disposed slightly above the top surface <NUM> of obturator <NUM>. With this arrangement, any interference between the obturator material and signals from the electromagnetic coil <NUM> of the navigational element <NUM> may be avoided.

Referring to <FIG>, a further alternative arrangement of an adapter <NUM> is shown. Adapter <NUM> is similar to adapter <NUM>. Like elements from the description of adapter <NUM> have been given similar reference numbers, increased by <NUM>. While adapter <NUM> provides for navigational element <NUM>/<NUM> to be retained within the channel <NUM> via the cooperating sizes of the channel <NUM> and an outside diameter of the navigational element <NUM>/<NUM> and/or use of a locking mechanism <NUM>, as a further alternative, an inside surface of the channel portions 214a, 214b may be formed with a compressible material to further frictionally retain the navigational element <NUM>, thereby relaxing manufacturing tolerances between the channel <NUM> and the navigational element <NUM>.

As yet a further exemplary arrangement, windows 403a may be provided with a spring element <NUM>. Spring element <NUM> includes a first end <NUM> and a free end <NUM>. The first end <NUM> is fixed to a proximal end of the window 403a, with the free end <NUM> biased to encroach within the channel <NUM>. When navigational element <NUM>/<NUM> is disposed within the channel <NUM>, the free end <NUM> of each spring element <NUM> will frictionally engage the outside surface of the navigational element <NUM>/<NUM>, thereby retaining the navigational element <NUM>/<NUM> within the channel <NUM>.

Referring to <FIG>, a further embodiment of a navigation adapter <NUM> for use with an obturator of a surgical access system. Adapter <NUM> is similar to adapters <NUM> and <NUM>. Like elements from the description of adapter <NUM> have been given similar reference numbers, increased by <NUM>. Adapter <NUM> is defined by first and second adapter casings <NUM>, <NUM>, a mounting piece <NUM> from which a positioning member <NUM> extends.

The first and second adapter casings <NUM>, <NUM> are each defined by a proximal end <NUM> and a distal end <NUM>. In some implementations, at least one of first adapter casing <NUM>, second adapter casing <NUM>, and mounting piece <NUM> may include locking mechanism <NUM> (best seen in <FIG>) or may include a spring element <NUM>.

First adapter casing <NUM> has a generally U-shaped cross-section and includes a navigational groove 514a defined between proximal end 510a and distal end 512a on an inner surface 522a of first adapter casing <NUM>. First adapter casing <NUM> may include at least one first cooperating member <NUM> disposed on at least one engaging surface 526a of first adapter casing <NUM>. In one exemplary configuration, the at least one first cooperating member <NUM> may be configured as a detent and have a thickened end <NUM>. As depicted in <FIG>, in one exemplary arrangement, the first adapter casing <NUM> has two first cooperating members <NUM> disposed generally at the center of the first adapter casing <NUM>, on either side of the navigation groove 514a. However, it is understood that this disclosure is not limited to this arrangement. Moreover, it is understood that additional cooperating members may be provided, similar to the arrangement depicted with respect to first adapter casing <NUM>. First adapter casing <NUM> is hingedly connected to mounting piece <NUM> to first adapter casing <NUM> by hinge element <NUM>.

Second adapter casing <NUM> is generally a mirror image of first adapter casing <NUM> and has a generally U-shaped cross-section and includes a navigational groove 514b defined between proximal end 510b and distal end 512b on an inner surface 522b of second adapter casing <NUM>. Second adapter casing <NUM> may include at least one second cooperating member <NUM> disposed on at least one engaging surface 526b of second adapter casing <NUM>.

The at least one second cooperating member <NUM> may be an indentation configured to permit engagement with a first cooperating member <NUM> in a complementary manner. In addition, an engagement tab <NUM> may be disposed within the indentations of second cooperating member <NUM> adjacent to an edge of the indentation of second cooperating member <NUM>. With this arrangement, the thickened end of the first cooperating member <NUM> may snap-fit around the engagement tab <NUM> to assist in locking the first and second adapter casings <NUM> and <NUM> together.

As depicted in <FIG>, in one exemplary arrangement, the second adapter casing <NUM> has two second cooperating members <NUM> disposed generally at the center of the second adapter casing <NUM>, on either side of the navigation groove 514b so as to generally correspond with the locations of the first cooperating members <NUM>. However, it is understood that this disclosure is not limited to this arrangement. Moreover, it is understood that additional cooperating members may be provided, similar to the arrangement depicted with respect to second adapter casing <NUM>. Second adapter casing <NUM> is hingedly connected to mounting piece <NUM> by hinge element <NUM>.

Mounting piece <NUM> is defined by a proximal end <NUM> and a distal end <NUM>. Distal end <NUM> of mounting piece <NUM> includes an annular angled surface (similar to that shown in <FIG>). The angled surface tapers from an outside diameter of the mounting piece <NUM> toward a positioning member <NUM> that extends from the distal end <NUM>. Similar to adapter <NUM>, the angled surface is configured to be complementary to chamfer <NUM> to seat the mounting piece <NUM> within obturator <NUM>.

A mounting opening <NUM> is formed through the proximal end <NUM>. Mounting opening <NUM> is in communication with a mounting piece channel, similar to mounting piece channel <NUM>. The mounting piece channel may be constructed of a predetermined size to accommodate navigational element <NUM> (<FIG>) therein. The mounting piece channel terminates in a closed distal end and may be configured to taper inwardly to define a seating portion similar to seating portion <NUM> that receives the distal tip <NUM> of navigational element <NUM>.

To assemble adapter <NUM>, the first and second casings <NUM>, <NUM> are pivoted from a non-operational position (as shown in <FIG>) about the hinge elements <NUM> and <NUM> brought into engagement with one another such that at least one first cooperating member <NUM> of first adapter casing <NUM> engages with the at least one second cooperating member <NUM> of second adapter casing <NUM>. This engagement may be a snap-fit arrangement that locks first and second adapter casings <NUM>, <NUM> together in a cooperating manner. When first adapter casing <NUM> is assembled with second adapter casing <NUM>, navigational grooves 514a, 514b combine to form the navigational channel <NUM> that is in communication with the mounting piece channel, similar to that shown in <FIG> to form a continuous channel. The continuous channel is in communication with proximal opening <NUM> of obturator, when adapter <NUM> is assembled to obturator <NUM>.

Once assembled, navigation element <NUM> may be disposed within combined navigational channel <NUM>/mounting piece channel, such that the distal tip <NUM> is directed into the seating portion. Once positioned, a locking mechanism <NUM> may be actuated to lock the navigational element <NUM> within adapter <NUM>, if provided.

It will be appreciated that the surgical access system described herein has broad applications. The foregoing embodiments were chosen and described in order to illustrate principles of the apparatuses as well as some practical applications. The preceding description enables others skilled in the art to utilize apparatuses in various embodiments and with various modifications as are suited to the particular use contemplated. In accordance with the provisions of the patent statutes, the principles and modes of operation of this disclosure have been explained and illustrated in exemplary embodiments.

Claim 1:
An adapter (<NUM>) for a surgical access assembly, comprising:
a first adapter casing (<NUM>);
a second adapter casing (<NUM>) selectively engageable with the first adapter casing (<NUM>); and
a mounting piece (<NUM>) selectively engaged with the first and second adapter casings (<NUM>, <NUM>), wherein in an engaged position the mounting piece (<NUM>) is positioned distally relative to the first and second adapter casings (<NUM>, <NUM>);
wherein the first adapter casing (<NUM>) and second adapter casing (<NUM>) cooperate to define a channel (<NUM>) that is configured to receive a navigation element (<NUM>), wherein the mounting piece (<NUM>) defines a mounting piece channel (<NUM>) that terminates in a closed distal end configured to receive a distal tip (<NUM>) of the navigation element (<NUM>), wherein the channel (<NUM>) is in communication with the mounting piece channel (<NUM>) to form a continuous channel in the engaged position,
wherein a portion of the mounting piece (<NUM>) is disposed within a portion of an inner surface of the first adapter casing (<NUM>) and a portion of an inner surface of the second adapter casing (<NUM>) to secure the mounting piece (<NUM>) to the first and second adapter casings (<NUM>, <NUM>); and
wherein the first adapter casing (<NUM>) includes an engagement channel (228a) adjacent to the distal end of the first adapter casing (<NUM>), the second adapter casing (<NUM>) includes an engagement channel (228b) adjacent to the distal end of the second adapter casing (<NUM>), and the mounting piece (<NUM>) includes a securing portion (<NUM>) that engages with the engagement channel (228a) of the first adapter casing (<NUM>) and the engagement channel (228b) of the second adapter casing (<NUM>).