Patent Publication Number: US-2016228139-A1

Title: Medical device and method for accessing space along an interior surface of an anatomic layer

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a division of U.S. patent application Ser. No. 13/799,777, filed Mar. 13, 2013, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     One or more embodiments of the subject matter described herein generally relate to a device or method for accessing an interior space that extends along an anatomic layer about an organ, such as the pericardium. 
     The human or animal body includes different anatomic layers that separate different regions of the body. In many cases, it is desirable to insert a device through an anatomic layer without subjecting the anatomic layer or any structures behind the layer to trauma. For example, the heart is enveloped within a multi-layered sac called the pericardium. Two of the layers, the visceral pericardium and the parietal pericardium, are normally in close contact with a thin layer of pericardial fluid therebetween. This space may be referred to as the pericardial space. Access to the pericardial space may be necessary or beneficial under a variety of circumstances. For instance, with access to the pericardial space, leads for a pacemaker or defibrillator may be implanted or placed at a particular location, pericardial fluid may be drained, drugs may be delivered more directly to a portion of the heart, and a variety of other diagnostic, therapeutic and/or surgical procedures may be performed. 
     One method of accessing the pericardial space includes inserting a shaft through a skin incision below the xiphoid. The shaft has a distal end that may be advanced into the body until the distal end presses against the pericardium. In the known method, the distal end of the shaft includes a number of pointed tines that are configured to grab and pull the parietal pericardium. More specifically, the tines are shaped so that when the shaft is rotated, the tines pierce the parietal pericardium and become embedded therein. In this manner, the distal end of the shaft effectively grabs the parietal pericardium. The multi-tined shaft may then be pulled backward to separate the parietal and visceral pericardia and expand the size of the pericardial space. With the pericardial space expanded, a Tuohy needle may be inserted through the shaft and pierce the parietal pericardium, thereby accessing the pericardial space. Certain tools and objects (e.g., a guidewire) may then be inserted into the pericardial space through the Tuohy needle. 
     In another known procedure, a distal end of a percutaneous tube is positioned against the parietal pericardium in a similar manner as described above. The tube has a flow channel that extends to an opening of the distal end. However, instead of grabbing the parietal pericardium with tines, the channel may be evacuated to effectively grab a portion of the parietal pericardium. Specifically, the vacuum pulls a localized portion of the parietal pericardium into the opening to form what is called a pericardial bleb. With the bleb formed in the opening, a needle may pierce the bleb to access the pericardial space. 
     Although known access tools, such as the multi-tined shaft and evacuated percutaneous tube, may be suitable for gaining access to the pericardial space, the tools have certain limitations, especially after access is obtained. For example, as described above, a number of different objects may be moved through the access tools after gaining access to the pericardial space. The insertion and removal of these objects may require careful manipulation of the access tool and the objects. Frequently, the doctor may use both hands to hold the access tool, which limits the doctor&#39;s ability to insert or remove the object through the access tool. In addition, with respect to the multi-tined shaft, inadvertent rotation of the shaft may withdraw the tines from the parietal pericardium causing the shaft to release the parietal pericardium before the procedure is completed. This undesired release further complicates the procedure and may increase the risk of trauma to the patient. 
     Accordingly, there is a need for a medical device that enables a doctor or other qualified person to access a space located behind an anatomic layer of an individual and allow the person to insert and remove objects without the limitations of known access tools. There is also a general need for more operator-friendly medical devices that reduce the risk of trauma to the patient during a medical procedure. 
     BRIEF DESCRIPTION 
     In accordance with an embodiment, a medical device is provided that includes a lift tool having a distal end configured to removably engage an anatomic layer. The lift tool includes a shaft lumen that extends longitudinally through the lift tool and opens at the distal end. The shaft lumen is configured to receive an elongated insert device that is movable through the shaft lumen and through the distal end. The medical device also includes a locking mechanism that is coupled to the lift tool. The locking mechanism includes a locking member that is selectively movable with respect to the insert device between a released position and an engaged position. The locking member engages the insert device when in the engaged position to hold the insert device at a fixed position with respect to the lift tool. The locking member permits the insert device to move through the shaft lumen when in the released position. 
     In some embodiments, the locking member may be held in the engaged position. For example, the locking member may be held in the engaged position without the operator gripping or holding the locking mechanism. 
     In certain embodiments, the lift tool includes a plurality of tines at the distal end that engage the anatomic layer. The lift tool may have a loading end with an opening to the shaft lumen. The locking mechanism may be coupled proximate to the loading end of the lift tool. 
     The locking mechanism may include a shaft passage that is aligned with the shaft lumen. The locking member may be selectively movable within the shaft passage to engage the insert device. The locking member may include at least one of an elastomeric member or a contoured surface. 
     In some embodiments, the medical device may include the locking mechanism and a torque applicator. The torque application may include an operator-controlled movable body and a biasing member that is coupled to the movable body and secured to the lift tool. The biasing member may be capable of being flexed when the movable body is moved to change a potential energy of the biasing member. The potential energy of the biasing member biases the lift tool in a designated rotational direction. 
     In particular embodiments, the distal end may be sized and shaped to operatively engage a parietal pericardium during a medical procedure. The shaft lumen may be sized and shaped to receive a hollowed needle. The locking member may be configured to hold the hollowed needle in a fixed position. 
     In another embodiment, a medical device is provided that includes a lift tool extending along a central axis and having a distal end. The distal end is configured to grip an anatomic layer when the lift tool is rotated about the central axis in a coupling direction. The lift tool has a shaft lumen that extends longitudinally through the lift tool and opens at the distal end. The shaft lumen is configured to receive an insert device that is movable through the shaft lumen and through the distal end. The medical device also includes a torque applicator that is coupled to the lift tool. The torque applicator includes an operator-controlled movable body and a biasing member. The biasing member operatively couples the lift tool and the movable body. The biasing member is flexed when the movable body is moved relative to the lift tool to change a potential energy of the biasing member. The potential energy of the biasing member biases the lift tool in the coupling direction. 
     In some embodiments, the potential energy causes a tactile resistance that is detectable by an operator engaging the movable body. As such, the operator may be assured that the lift tool is still operably engaged to the anatomic layer. 
     The movable body may be configured to rotate about the central axis. For example, the biasing member may permit the movable body to be rotated about the central axis at least about 90° in a decoupling direction that is opposite the coupling direction while maintaining a rotational force in the coupling direction. 
     In certain embodiments, the biasing member includes a torsion spring having first and second ends. The first end may be secured with respect to the lift tool, and the second end may be secured to the movable body. Optionally, the torque applicator may also include a shaft holder that has a fixed position with respect to the lift tool. The shaft holder may secure a portion of the biasing member with respect to the lift tool. 
     Embodiments described herein may be particularly suitable for cardiac procedures, such as lead implantation or placement. As such, the medical devices may also be characterized as intrapericardial access tools or devices that are configured to expand the pericardial space. For example, the distal end of the lift tool may grab the parietal pericardium in a manner than enables the operator (e.g., doctor) to pull the parietal pericardium away from the visceral pericardium using the shaft. A needle and other objects may be inserted through the lumen of the lift tool. 
     In one embodiment, a method for accessing space along an interior surface of an anatomic layer is provided. The method includes coupling a distal end of a lift tool to an exterior surface of the anatomic layer. The lift tool includes a shaft lumen that extends longitudinally through the lift tool and through the distal end. The method also includes inserting an insert device through the shaft lumen. The method also includes selectively moving a locking member with respect to the insert device from a released position to an engaged position. The locking member engages the insert device when in the engaged position to hold the insert device in a fixed position with respect to the lift tool. 
     The distal end of the lift tool may include layer-engaging projections. In some embodiments, the coupling operation may include rotating the lift tool to embed the projections into the anatomic layer. The method may also include moving the anatomic layer to adjust the space along the interior surface of the anatomic layer. 
     In another embodiment, a method for accessing space along an interior surface of an anatomic layer is provided. The method includes engaging a distal end of a lift tool to an exterior surface of the anatomic layer. The lift tool includes a shaft lumen that extends longitudinally through the lift tool and through the distal end. The method also includes rotating the lift tool about a central axis of the lift tool in a coupling direction to grip the anatomic layer with the distal end. The method also includes moving an operator-controlled movable body to change a potential energy of a biasing member that is coupled to the movable body. The biasing member is secured with respect to the lift tool, wherein the potential energy of the biasing member biases the lift tool in the coupling direction so that the distal end maintains a grip on the anatomic layer. The method also includes inserting an insert device through the shaft lumen. 
     In some embodiments, the rotating operation and the moving operation are caused by separate rotational strokes from the operator. In other embodiments, the rotating and moving operations may be caused by the same stroke from the operator. For example, rotating the movable body may cause the lift tool to engage the anatomic layer and may also cause a change in the potential energy of the biasing member. 
     While multiple embodiments are disclosed, still other embodiments of the described subject matter will become apparent to those skilled in the art from the following Detailed Description, which shows and describes illustrative embodiments of disclosed inventive subject matter. As will be realized, the inventive subject matter is capable of modifications in various aspects, all without departing from the spirit and scope of the described subject matter. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view of a medical device formed in accordance with one embodiment. 
         FIG. 2A  is a side view of a distal end of the medical device of  FIG. 1  in accordance with one embodiment prior to insertion through an incision. 
         FIG. 2B  is a side view of the distal end of the medical device of  FIG. 1  prior to engaging an anatomic layer. 
         FIG. 3  is a side view of the distal end of the medical device of  FIG. 1  after engaging and pulling the anatomic layer. 
         FIG. 4  illustrates a cross-section of a torque applicator formed in accordance with one embodiment that may be used by the medical device of  FIG. 1 . 
         FIG. 5  is an end view of a biasing member on a lift tool that may be used by the torque applicator of  FIG. 4 . 
         FIG. 6  is another end view of the biasing member on the lift tool that may be used by the torque applicator of  FIG. 4 . 
         FIG. 7  illustrates a cross-section of a torque applicator formed in accordance with one embodiment that may be used by the medical device of  FIG. 1 . 
         FIG. 8  is an end view of biasing members coupled to a lift tool that may be used by the torque applicator of  FIG. 7 . 
         FIG. 9  is a side cross-section of a locking mechanism formed in accordance with one embodiment that may be used with the medical device of  FIG. 1 . 
         FIG. 10  is an end cross-section of the locking mechanism that may be used with the medical device of  FIG. 1 . 
         FIG. 11  is an end cross-section of the locking mechanism that may be used with the medical device of  FIG. 1 . 
         FIG. 12  is a side cross-section of a locking mechanism formed in accordance with one embodiment that may be used with the medical device of  FIG. 1 . 
         FIG. 13  is the side cross-section of the locking mechanism of  FIG. 12  as the locking mechanism is holding an insert device in a fixed position. 
         FIG. 14  is a side cross-section of a locking mechanism formed in accordance with one embodiment that may be used with the medical device of  FIG. 1 . 
         FIG. 15  is the side cross-section of the locking mechanism of  FIG. 14  as the locking mechanism is holding an insert device in a fixed position. 
         FIG. 16  is an image of a medical device formed in accordance with one embodiment. 
         FIG. 17  is an image of another medical device formed in accordance with one embodiment. 
         FIG. 18  is a flowchart illustrating a method of accessing an anatomic space in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments described herein include medical devices or access tools that enable a doctor or other qualified individual (hereinafter referred to as the operator or user) to access an anatomical space located behind an anatomic layer or wall. Although it may be suitable for the operator to directly grip the medical device, it may also be possible for the operator to control the medical device with, for example, a robotic arm. The anatomic layer may be movable (e.g., partially flexible or pliable) such that the anatomic layer may be pulled away from another structure located behind the anatomic layer. The medical device may provide a passageway that directs an insert device, such as a needle, into and through the anatomic layer. 
     Embodiments may include a lift tool or body that defines the passageway and receives the insert device for inserting the insert device through the anatomic layer and into the space. The lift tool may have a distal end that is configured to operatively engage or couple (e.g., grip or grab) a localized area along the anatomic layer so that localized area may be held against the distal end while the insert device is inserted. The operative engagement may be capable of holding the anatomic layer as an operator pulls the anatomic layer to enlarge the space behind the anatomic layer. In one or more embodiments, the operative engagement may be accomplished using projections or tines that are embedded into the anatomic layer. However, other embodiments may provide a suction force through the lift tool to draw a bleb into an end of the lift tool. 
     The medical device may also include at least one of a locking mechanism or a torque applicator. The locking mechanism may engage and hold the insert device in a fixed position relative to the locking mechanism or the lift tool. In such cases, the locking mechanism may allow the operator to use at least one of his or her hands for other purposes. The torque applicator may assist in maintaining the operative engagement between the lift tool and the anatomic layer. For example, after the lift tool is operatively engaged to the anatomic layer, the torque applicator may tolerate movement of the lift tool while still maintaining the operative engagement. In addition, the torque applicator may provide a tactile indication to the operator that confirms the anatomic layer is still operatively engaged to the lift tool. 
     Embodiments set forth herein may be suitable or particularly useful for accessing a space between different layers of the pericardium (e.g., the pericardial space). In certain embodiments, the anatomic layer is part of the outer layers of the heart, such as the parietal pericardium. In such cases, the medical device may be referred to as an intrapericardial access device. However, the medical devices set forth herein may also be implemented in other applications in which it is desirable to engage and hold an anatomic layer for inserting an object through the layer. 
       FIG. 1  is a schematic side view of a medical device  100  formed in accordance with one embodiment. As shown, the medical device  100  extends longitudinally between an operative end portion  102  and a proximal portion  104 . An intermediate portion (not shown) may join the operative end and proximal portions. The operative end portion  102  is configured to engage an anatomic layer  140  (shown in  FIG. 2B ) of an Individual (e.g., human or non-human patient). In some cases, the operative end portion  102  is configured to be inserted into the individual. The proximal portion  104  is configured to be handled by an operator and may include mechanisms for controlling different functions and features of the medical device  100  as described herein. 
     The medical device  100  includes a lift tool or body  106 . The lift tool  106  extends longitudinally along a central axis  110  between a distal end or tip  108  and a loading end  112 . The operative end portion  102  includes the distal end  108 . Optionally, the proximal portion  104  may include the loading end  112 . The lift tool  106  includes a shaft lumen  114  (indicated in phantom) that is configured to receive an insert device  116 . The central axis  110  may extend through the shaft lumen  114  and along a geometric center of a cross-section of the lift tool  106  that is taken transverse to the central axis  110 . The shaft lumen  114  extends longitudinally through the lift tool  106  between a first opening  118  and a second opening  120 . The first and second openings  118 ,  120  may also be referred to as distal and trailing openings. The distal and loading ends  108 ,  112  may include the distal and trailing openings  118 ,  120 , respectively. The trailing opening  120  permits an insert device  116  to be loaded into the lift tool  106 , and the distal opening  118  permits the insert device  116  to extend beyond or clear the distal end  108  of the lift tool  106  for insertion into the anatomic layer  140 . 
     The shaft lumen  114  may be dimensioned to permit different types of insert devices to be inserted therein. In the illustrated embodiment, the insert device  116  is a hollowed needle (e.g., Tuohy needle), which may extend entirely through the lift tool  106  and through the distal end  108  as shown in  FIG. 1 . A variety of insert devices, however, may be used, provided that the objects inserts are suitably dimensioned. For example, additional insert devices may include obturators, stylets, other types of needles, tubes, guidewires, fiber-optic cable, and the like. In many instances, a first insert device may function as a tube that directs a second insert device therethrough. For example, a Tuohy needle may be inserted into and through the lift tool  106  and a guidewire may be inserted into and through the Tuohy needle. 
     In the illustrated embodiment, the lift tool  106  extends linearly along the central axis  110  and has a rigid or inflexible body. For example, the lift tool  106  may be a single continuous component that is formed from a rigid material, such as stainless steel. Other rigid materials that are suitable (e.g., biocompatible) for being inserted into a patient&#39;s body may be used. In other embodiments, the lift tool  106  may have a non-linear shape. Furthermore, in other embodiments, the lift tool  106  may be partially flexible along an entire length or at certain portions of the lift tool  106 . 
     An enlarged portion of the distal end  108  is shown in  FIG. 1 . The distal end  108  includes an end edge  130 , which may define a dimension  131  (e.g., diameter) of the distal opening  118 . In some embodiments, the end edge  130  faces along the central axis  110  in an insertion direction Z 1  and the distal opening  118  opens in the insertion direction Z 1 . In such embodiments, when the medical device  100  is advanced in the insertion direction Z 1 , the lift tool  106  is aligned with (e.g., the central axis  110  may be aligned with) the insertion direction Z 1 . However, in alternative embodiments, the distal opening  118  may open laterally with respect to the insertion direction Z 1 . Such embodiments may be particularly applicable when the lift tool  106  (or a portion thereof) is evacuated for forming a bleb. 
     In the illustrated embodiment, the distal end  108  includes pointed layer-engaging projections (e.g., tines)  132 . The projections  132  are shaped to pierce through the anatomic layer  140  when the distal end  108  is moved into the anatomic layer  140  with sufficient force. As shown, the projections  132  may be curved or partially helical, although other shapes may be used. When the lift tool  106  is moved to engage the anatomic layer  140 , the lift tool  106  may be rotated about the central axis  110  in a designated manner. In the illustrated embodiment, the projections  132  are formed from the same material as the lift tool  106 . As such, the projections  132  may also be formed from a rigid material, such as stainless steel. In other embodiments, the projections  132  may be more flexible or movable. 
     The medical device  100  may also include a torque applicator  122  and an operator-controlled locking mechanism  124  that are coupled to the lift tool  106 . In  FIG. 1 , the torque applicator  122  and the locking mechanism  124  are separate bodies with different axial locations along the central axis  110 . However, in other embodiments that include each of the torque applicator  122  and the locking mechanism  124 , the structures and functions of the torque applicator  122  and the locking mechanism  124  may be integrated into a single body. 
     As described herein, the torque applicator  122  may apply a rotational force RF (shown in  FIG. 3 ) to the lift tool  106  that facilitates maintaining an operative engagement between the distal end  108  and the anatomic layer  140 . In some embodiments, the rotational force RF may also facilitate with the initial insertion of the projections  132  into the anatomic layer  140 . The torque applicator  122  may be tolerant or yielding such that the torque applicator  122  is permitted to rotate the lift tool  106  in a direction that is opposite of the rotational force RF without the distal end  108  and the anatomic layer  140  becoming disengaged. The torque applicator  122  may also provide a tactile indication to the operator that confirms the distal end  108  and the anatomic layer  140  are still engaged. As shown, the torque applicator  122  includes an operator-controlled movable body  126  that is configured to be engaged (e.g., gripped and moved) by the operator. 
     The locking mechanism  124  is configured to be actuated by the operator to selectively lock the insert device  116  in a designated position. The locking mechanism  124  may be adjustable or movable between a released position and an engaged position. In the engaged position, the locking mechanism  124  may hold the insert device  116  at a designated axial location with respect to the central axis  110  or with respect to the lift tool  106 . Optionally, the locking mechanism  124  may also be configured to hold the insert device  116  in a designated rotational orientation. For example, the insert device  116  may be rotated and then locked in a fixed position such that a beveled end  141  of the insert device  116  faces in a designated radial direction. In  FIG. 1 , the beveled end  141  faces out of the page. 
     An Intermediate portion of the lift tool  106  has been removed in  FIG. 1  for illustrative purposes. Nonetheless, the lift tool  106  and the medical device  100  may have a variety of lengths. For example, the lift tool  106 , measured from a leading face  143  of the torque applicator  122  to the distal end  108 , may have a length that is between about 8 centimeters (cm) to about 40 cm or, more specifically, about 15 cm to about 30 cm. However, the above dimensions are just examples and the medical device  100  and the lift tool  106  may have different configurations. 
       FIGS. 2A, 2B, and 3  illustrate side views of the distal end  108  of the medical device  100  ( FIG. 1 ). It should be noted that  FIGS. 2A, 2B, and 3  are used only for illustration and that the relative dimensions shown in  FIGS. 2A, 2B, and 3  are not necessarily accurate. In  FIG. 2A , the distal end  108  is configured to be inserted into an individual (e.g., patient). During a procedure in which the lift tool  106  of the medical device  100  is inserted into the patient, an incision (not shown) may be first made at a designated area of the patient (e.g., along the skin). Before the lift tool  106  is inserted through the incision, an obturator  190  may be advanced into the shaft lumen  114  ( FIG. 1 ) and positioned so that the obturator  190  extends beyond the end edge  130  and beyond the projections  132  of the lift tool  106  as shown in  FIG. 2A . In the illustrated embodiment, the obturator  190  is dimensioned to fill the shaft lumen  114  at the distal end  108 . When the distal end  108  is inserted into the incision, the obturator  190  may block or obstruct flow of material into the shaft lumen  114 . In addition, the obturator  190  may reduce the likelihood that the projections  132  snag tissue or other material in the body as the lift tool  106  is inserted. 
     In  FIG. 2B , the distal end  108  of the lift tool  106  is positioned proximate to the anatomic layer  140 . The anatomic layer  140  has first and second surfaces  142 ,  144  with a thickness of the anatomic layer  140  extending therebetween. As shown, the second surface  144  extends along and defines an anatomical space  146 . In some cases, another anatomic layer  148  may be positioned adjacent to the anatomic layer  140  with the anatomical space  146  located therebetween. In particular embodiments, the anatomic layer  140  is the parietal pericardium, the anatomic layer  148  is the visceral pericardium, and the anatomical space  146  is the pericardial space. However, as noted herein, embodiments may be used with other anatomic layers. 
     During the gripping operation, the distal end  108  may be pressed against (e.g., directly engage) the first surface  142  of the anatomic layer  140 . For example, as the distal end  108  is inserted through an incision (not shown) and into the body, the operator may sense or detect (e.g., based on tactile feel) that the distal end  108  is against the anatomic layer  140 . With respect to intrapericardial access devices, the operator may sense palpitations or contractions of the heart. While pressed against the anatomic layer  140 , the lift tool  106  may be rotated in a coupling direction C 1 , which in  FIG. 2B  is clockwise from the viewpoint of the operator looking down the lift tool  106  toward the anatomic layer  140 . As the lift tool  106  is rotated in the coupling direction C 1 , the projections  132  may pierce the anatomic layer  140 . In some cases, the projections  132  may pierce or partially pierce the anatomic layer  140  prior to rotation. 
     With the anatomic layer  140  initially penetrated, continued rotation of the lift tool  106  may drive the projections  132  deeper into the anatomic layer  140  and bring the end edge  130  and the anatomic layer  140  close to each other as shown in  FIG. 3 . More specifically, the shape of the projections  132 , the rotation of the lift tool  106  in the coupling direction, and the pliable nature of the anatomic layer  140 , may cause the anatomic layer  140  to be pulled toward the end edge  130  and/or cause the lift tool  106  to be pulled toward the anatomic layer  140 . In the illustrated embodiment, the projections  132  may clear the thickness of the anatomic layer  140  and extend beyond the second surface  144 . However, in other embodiments, the projections  132  may not clear the second surface  144 . 
     With the anatomic layer  140  and the distal end  108  operatively engaged, the operator is permitted to move the lift tool  106  in a withdrawal direction W 1  ( FIG. 3 ) that is opposite the insertion direction Z 1  ( FIG. 2B ). As such, the anatomical space  146  may be enlarged or expanded. In some embodiments, the distal end  108  may be configured such that a localized portion  150  of the anatomic layer  140  spans across the distal opening  118  ( FIG. 2B ) and is held against the end edge  130 . The localized portion  150  may be held is a substantially fixed position with respect to the end edge  130  as the insert device  116  ( FIG. 1 ) is inserted through the localized portion  150 . 
     With respect to  FIG. 3 , when the distal end  108  is operatively engaged to the anatomic layer  140  as shown and the lift tool  106  is rotationally steady (e.g., is not being actively rotated), the distal end  108  remains engaged to the end edge  130  due to the shape of the projections  132 . However, rotating the lift tool  106  in a decoupling direction C 2  (e.g., counter-clockwise) that is opposite the coupling direction C 1  would cause the anatomic layer  140  to slide along the projections  132 . The end edge  130  and the anatomic layer  140  may then separate and, in some cases, the anatomic layer  140  may be released from the projections  132 . As such, in some embodiments, it may be desirable to maintain at least some rotational force RF in the coupling direction C 1 . The rotational force RF may maintain tension that resists rotational movement of the lift tool  106  in the decoupling direction C 2  and/or resists movement of the anatomic layer  140  away from the end edge  130 . 
       FIG. 4  shows a cross-section of the torque applicator  122  in accordance with one embodiment. The torque applicator  122  may include the operator-controlled movable body  126 , a shaft or tool holder  152 , and a biasing member  154 . The torque applicator  122  is configured to apply the rotational force RF ( FIG. 3 ) to the lift tool  106  to facilitate maintaining the operative engagement with the anatomic layer  140  ( FIG. 2B ). In some embodiments, the torque applicator  122  may also be used to initially grab or grip the anatomic layer  140 , for example, a single common stroke (e.g., rotation of the movable body) may cause the lift tool  106  to engage the anatomic layer  140  and also cause the lift tool  106  to provide the rotation force RF. It is noted, however, that the embodiment shown in  FIG. 4  is just one example of a torque applicator that can be used with the medical devices described herein and others can be used. 
     As shown, the movable body  126  has an exterior surface  202  and an interior surface  204 . The exterior surface  202  is configured to be engaged (e.g., gripped) by the operator. As such, the exterior surface  202  may be shaped to facilitate gripping by the operator. For example, the exterior surface  202  may include knurling or threads. The exterior surface  202  includes end portions  208 ,  210  that face in opposite directions along the central axis  110 . In the illustrated embodiment, the end portion  208  faces toward the distal end  108  ( FIG. 1 ) of the lift tool  106 . In other embodiments, however, the end portion  210  may face toward the distal end  108 . As shown, the end portion  208  includes a shaft opening  212  and the end portion  210  includes a body opening  214 . In the embodiment of  FIG. 4 , the shaft and body openings  212 ,  214  are sized and shaped to receive, at the very least, the lift tool  106 . The body opening  214  may also be dimensioned to receive the shaft holder  152 . 
     The interior surface  204  may define a shaft-engaging portion  216  that engages the lift tool  106 . For example, the shaft-engaging portion  216  may extend circumferentially around the lift tool  106  with a slidable interface  220  located therebetween. The interior surface  204  also defines a body cavity  206  that opens to and extends between the shaft and body openings  212 ,  214 . In addition to the lift tool  106 , the body cavity  206  may be sized and shaped to receive the shaft holder  152  and the biasing member  154 . 
     The biasing member  154  defines a shaft-receiving opening  222  (shown in  FIGS. 5 and 6 ) and includes member ends  224 ,  226  that are configured to engage the shaft holder  152  and the movable body  126 , respectively. For example, the shaft holder  152  and the movable body  126  may have cavities  153 ,  127 , respectively, that receive and engage the member ends  224 ,  226 , respectively. The member ends  224 ,  226  may be engaged to the respective cavities  153 ,  127  through, for example, an interference fit and/or depositing an adhesive in the cavities  153 ,  127 . The shaft-receiving opening  222  is dimensioned to receive the lift tool  106 . In the illustrated embodiment, the biasing member  154  is a torsion spring, but other biasing members capable of functioning as described herein may be used. 
     The interior surface  204  of the movable body  126  includes a holder-engaging portion  228  and forms a slidable interface  230  with an outer surface  232  of the shaft holder  152 . In the Illustrated embodiment, the outer surface  232  faces radially away from the central axis  110  and the holder-engaging portion  228  of the interior surface  204  faces radially-inward toward the central axis  110 . As shown, the shaft holder  152  may include an open-sided channel or groove  242  that opens to the interface  230  and the movable body  126 . 
     When the medical device  100  ( FIG. 1 ) is assembled, the distal end  108  or the loading end  112  ( FIG. 1 ) of the lift tool  106  may be inserted through the body cavity  206  of the shaft holder  152  and the shaft-receiving opening  222  of the biasing member  154 . The biasing member  154  may be secured to the shaft holder  152  by inserting the member end  224  into the cavity  153  and forming, for example, an interference fit. 
     The shaft holder  152  may also be affixed to the lift tool  106 . For example, the shaft holder  152  may be secured to the lift tool  106  in a fixed position so that the lift tool  106  and the shaft holder  152  move with each other when the shaft holder  152  is moved. The shaft holder  152  may be affixed to the lift tool  106  in various manners. For example, the shaft holder  152  may include a thru-hole  236  that extends from the outer surface  232  of the shaft holder  152  to an inner surface  234  of the shaft holder  152 . The inner surface  234  faces radially-inward and may define a shaft passage  238  of the shaft holder  152 . The shaft passage  238  is dimensioned to receive the lift tool  106 . In some embodiments, a fastener  235  (e.g., plug, set screw, and the like) may be inserted into the thru-hole  236  and directly engage an outer surface  240  of the lift tool  106  thereby affixing the lift tool  106  and the shaft holder  152  to each other. 
     Alternatively or in addition to, an adhesive may be placed along the inner surface  234  or the outer surface  240  of the lift tool  106  to affix the lift tool  106  and the shaft holder  152  to each other. As another example, the lift tool  106  and the shaft holder  152  may include complementary projections and recesses to form a snap-fit engagement. Furthermore, a clamp ring may surround the shaft holder  152  with the lift tool  106  positioned in the shaft passage  238  and the clamp ring may be clamped using, for example, a screw to increase the frictional engagement between the shaft holder  152  and the lift tool  106 . In another embodiment, the shaft holder  152  and the lift tool  106  may be integrally formed through, for example, a common molding process. Such a shaft holder may include the member cavity  153  and/or the channel  242 . 
     After the shaft holder  152 , the biasing member  154 , and the lift tool  106  are assembled together, the lift tool  106  may then be inserted through the body and shaft openings  214 ,  212  and the body cavity  206  of the movable body  126 . The movable body  126  may be positioned to surround the shaft holder  152  and the biasing member  154 . 
     In other embodiments, the movable body  126 , the shaft holder  152 , and the biasing member  154  may be pre-assembled as shown in  FIG. 4  and then the lift tool  106  may be inserted therethrough. The shaft holder  152  may then be affixed to the lift tool  106  as described above or in another manner. 
     In the illustrated embodiment, when the medical device  100  is fully assembled, the movable body  126  is capable of being rotated around the shaft holder  152  or, more specifically, around the lift tool  106  and the central axis  110 . In some embodiments, the movable body  126  may include a thru-hole  244  for receiving a fastener  245  (e.g., set screw, plug, and the like) that extends through the thru-hole  244  and into the channel  242 . The fastener  245  may be configured to prevent the movable body  126  and the shaft holder  152  from moving relative to each other along the central axis  110 . 
     In some embodiments, the fastener  245  may also limit an amount of rotation of the movable body  126 . For instance, the channel  242  may not extend entirely around a circumference of the shaft holder  152 . By way of a specific example, the channel  242  may only extend between about 270° and 180° about the central axis  110 . In such cases, when the movable body  126  is rotated, the fastener  245  may engage, for example, a surface of the shaft holder  152  thereby stopping rotation of the movable body  126 . 
       FIGS. 5 and 6  illustrate isolated end views of the biasing member  154  and the lift tool  106 . In particular,  FIGS. 5 and 6  illustrate views looking down the lift tool  106  from the distal end  108  ( FIG. 1 ) toward the biasing member  154 . The member ends  224 ,  226  are shown and are in the 12 o&#39;clock and 6 o&#39;clock positions, respectively. 
     For some of the embodiments set forth herein, the biasing member is configured to be moved or adjusted between different positions or configurations to change a potential energy of the biasing member. The biasing member  154  has a first condition in  FIG. 5  and a second condition in  FIG. 6 . For some embodiments, the first condition may be a relaxed condition of the biasing member  154  and the second condition may be a biased condition in which the biasing member exerts a rotational force to return the biasing member to the first condition. In other embodiments, the biasing member  154  may be pre-loaded such that each of the first and second conditions is a biased condition, but the second condition is more biased such that the biasing member  154  exerts a greater rotational force in the second condition than in the first condition. 
     With respect to the illustrated embodiment, when the movable body  126  ( FIG. 1 ) is rotated about the lift tool  106  as described with respect to  FIG. 4 , a potential energy of the biasing member  154  is changed. More specifically, when the movable body  126  is rotated in the coupling direction C 1  ( FIG. 2B ), the member end  226  is moved from a first radial position  250  to a second radial position  252 . The biasing member  154  is configured such that the change in radial positions of the biasing member  154  increases the potential energy of the biasing member  154 . 
     The potential energy of the biasing member  154  may correspond or correlate to the rotational force RF ( FIG. 3 ). More specifically, in the illustrated embodiment, the biasing member  154  is secured to the shaft holder  152  due to the coupling of the member end  224  and the cavity  153  ( FIG. 4 ). The member end  224  has a fixed relationship with respect to the lift tool  106 , and the member end  226  has a fixed relationship with respect to the movable body  126 . As such, the biasing member  154  is secured to the lift tool  106  and to the movable body  126 . When the distal end  108  is operatively engaged to the anatomic layer  140  ( FIG. 2B ) and the movable body  126  is rotated in the coupling direction C 1  ( FIG. 2B ), the member end  226  rotates with the movable body  126  about the central axis  110 . However, the member end  224  is secured to the shaft holder  152 , which is affixed to the lift tool  106 . The lift tool  106  is operatively engaged to the anatomic layer  140  such that the lift tool  106  is prevented from rotating. As such, the member end  224  is unable to rotate about the central axis  110 . 
     Accordingly, when the movable body  126  is rotated in the coupling direction C 1 , the position or configuration of the biasing member  154  changes in a manner that increases the potential energy of the biasing member  154 . More specifically, the change in the radial position of the member end  226  may cause an increase in the potential energy. The increase in potential energy of the biasing member  154 , consequently, causes or increases the rotational force RF of the lift tool  106 . The rotational force RF facilitates maintaining the operative engagement between the distal end  108  and the anatomic layer  140 . For example, rotational force RF may increase the frictional engagement between the anatomic layer  140  and the projections  132  that pierce the anatomic layer  140 . 
     Notably, at least some level or amount of the rotational force RF is maintained even when the movable body  126  is rotated in limited amounts in the decoupling direction (i.e., in the direction opposite of the coupling direction C 1 ). As shown in  FIG. 6 , if the movable body  126  is rotated in the decoupling direction about 900 to a third radial position  254 , the potential energy of the biasing member  154  in the third radial position  254  is still greater than the potential energy of the biasing member  154  in the first radial position  250 . Accordingly, the rotational force RF may still be applied at the distal end  108  even if rotation of the movable body  126  in the decoupling direction occurs. 
     In some embodiments, the biasing member  154  may also provide a tactile indication to the operator that the operative engagement between the distal end  108  and the anatomic layer  140  still exists. More specifically, when the member end  226  is in the second or third radial positions  252 ,  254  (or other radial position between the first and second radial positions  250 ,  252 ), the operator may sense or detect a rotational force that resists movement in the coupling direction C 1 . For example, in some cases, if the operator were to release the movable body  126  when the tactile resistance is detected, the biasing member  154  may rotate the movable body  126  in the decoupling direction until the member ends  224 ,  226  are positioned as shown in  FIG. 5 . Accordingly, the operator may confirm that the operative engagement exists due to the tactile resistance provided by the biasing member  154 . 
       FIGS. 7 and 8  illustrate alternative embodiments of a torque applicator that may be used with the medical device  100  ( FIG. 1 ). The rotational force RF and the tactile resistance may be provided by other torque applicator configurations. For example,  FIG. 7  shows a torque applicator  260  that is similarly constructed to the torque applicator  122  ( FIG. 1 ). For example, the torque applicator  260  includes an operator-controlled movable body  262 , a shaft or tool holder  264 , and a biasing member  266 . The biasing member  266  may be similar to or identical to the biasing member  154  ( FIG. 3 ). In the illustrated embodiment, the shaft holder  264  is affixed to a lift tool  268 . For example, although not shown, the shaft holder  264  may be affixed to the lift tool  268  using a set screw, plug, or adhesive. The shaft holder  264  and the lift tool  268  may also have complementary projections/recesses for forming a snap-fit engagement. As shown, the biasing member  266  has member ends  270 ,  272  that are inserted into cavities  271 ,  273 , respectively, of the movable body  262  and the shaft holder  264 , respectively. 
     The movable body  262  and the shaft holder  264  may engage each other along a slidable interface  274 . As shown, the shaft holder  264  may have an open-sided channel  276  that receives an annular projection  278  of the movable body  262 . In some embodiments, the channel  276  and projection  278  may be configured to limit the rotation of the movable body  262 . 
     In the illustrated embodiment, the movable body  262  is configured to rotate about the lift tool  268 . Like the biasing member  154  as described in  FIGS. 5 and 6  above, the position or configuration of the biasing member  266  changes in a manner that increases the potential energy of the biasing member  266 . Accordingly, the biasing member  266  may provide a rotational force and a tactile indication as described with respect to the torque applicator  122 . 
     In some embodiments, the movable body  262  has an outer surface  280  and the shaft holder  264  has an outer surface  282  in which at least one of the outer surfaces  280 ,  282  has visible indicators that indicate to the operator that the movable body  262  is applying torque to the lift tool  268 . For example, the outer surface  280  may have a series of white lines that are distributed circumferentially around the outer surface  280  in which each line extends along an axial direction. Numbers may be located next to the lines to indicate the number of degrees that the movable body  262  has been rotated. The shaft holder  264  may have a reference line along the outer surface  282  that may be used in conjunction with the lines of the movable body  262 . 
       FIG. 8  shows an isolated end view of an operator-controlled movable body  284  and a lift tool  286  in a first rotational arrangement  288  and in second rotational arrangement  290 . The perspective of  FIG. 8  is from a loading end (not shown) of the lift tool  286  toward the distal end (not shown). In the first rotational arrangement  288 , the movable body  284  has not been rotated about the lift tool  286 . In the second rotational arrangement  290 , the movable body  284  has been rotated about 60° about the lift tool  286  in a coupling direction (e.g., clockwise). 
     In the illustrated embodiment, biasing members  292 ,  293  extend between an inner surface  285  of the movable body  284  and an outer surface  287  of the lift tool  286 . The biasing members  292 ,  293  may be rubber bands or other elastic members that are capable of being stretched and substantially returning to an original shape. The biasing members  292 ,  293  are attached to respective hooks or clips  295  along the inner and outer surfaces  285 ,  287 . When the movable body  284  is rotated in the coupling direction, the biasing members  292 ,  293  are stretched longitudinally. As the biasing members  292 ,  293  are stretched, a potential energy in the biasing members  292 ,  293  increases. As described above, the potential energy may be translated into a rotational force that facilitates maintaining the operative engagement with the anatomic layer. The potential energy may also provide a tactile resistance to the operator that the lift tool  286  and the anatomic layer are still operatively engaged. 
     Alternatively or in addition to a torque applicator, embodiments described herein may include a locking mechanism that is configured to hold at least one insert device that extends within a lift tool. Such locking mechanisms may include a locking member that is movable with respect to the insert device. In particular, the locking member may be moved between an engaged position, in which the insert device is in a substantially fixed position, and a released position, in which the insert device is permitted to move axially through the lift tool. 
     For example,  FIGS. 9-11  illustrate the locking mechanism  124  that is coupled to the lift tool  106  and may be used with the medical device  100  ( FIG. 1 ). More specifically,  FIG. 9  is a cross-section of the locking mechanism  124  coupled to the lift tool  106 . For illustrative purposes, the lift tool  106  is not shown in a cross-sectional view in  FIG. 9 . As shown in  FIG. 9 , the locking mechanism  124  may be coupled proximate to the loading end  112  of the lift tool  106 . The loading end  112  includes the opening  120  that is sized and shaped to receive the insert device  116 . 
     In the illustrated embodiment, the locking mechanism  124  includes a locking member  302  and a shaft or tool holder  304  that surrounds the lift tool  106 . The shaft holder  304  has a cylindrical shape in  FIGS. 9-11  that extends lengthwise along the lift tool  106 . However, the shaft holder  304  may have other geometries in alternative embodiments. The shaft holder  304  may directly engage the lift tool  106  and have a fixed position with respect to the lift tool  106 . For example, the shaft holder  304  may be directly engaged to the lift tool  106  through hardware (e.g., fasteners) and/or use of an adhesive. The shaft holder  304  is configured to hold the locking member  302  proximate to the lift tool  106 . To this end, the shaft holder  304  may include component passages  314 ,  316  that extend entirely through the shaft holder  304  and intersect each other at a core region  318 . The component passage  314  is sized and shaped to receive the locking member  302 , and the component passage  316  is sized and shaped to receive the lift tool  106 . The component passage  316  extends along the central axis  110  (shown in  FIGS. 10 and 11 ). The component passage  314  extends in a direction that is transverse to the central axis  110 . 
     The insert device  116  is configured to be inserted into and positioned within the shaft lumen  114  of the lift tool  106 . As shown, the lift tool  106  includes a lock opening  310 . The lock opening  310  is an opening within the lift tool  106  that is located to receive the locking member  302 . The lock opening  310  exposes an outer surface  312  of the insert device  116  to an exterior of the lift tool  106 . The lock opening  310  is configured to receive an engagement surface  308  of the locking member  302  and permit the engagement surface  308  to directly engage the insert device  116 . 
       FIG. 10  is an end cross-section of the locking mechanism  124  taken along the line  10 - 10  in  FIG. 9  and illustrates the locking mechanism  124  in a released position.  FIG. 11  is the end cross-section of the locking mechanism  124  in an engaged position. The locking member  302  is selectively movable with respect to the shaft holder  304  and the insert device  116 . As shown, the locking member  302  includes a shaft cavity  320 . The shaft cavity  320  may be partially defined by an engagement or interior surface  308  of the locking member  302 . The engagement surface  308  is configured to be positioned proximate to (e.g., near or within) the lock opening  310  ( FIGS. 9 and 10 ). 
     The shaft cavity  320  may be dimensioned to receive the lift tool  106 . In particular embodiments, the shaft cavity  320  has a first dimension  322  that is slightly larger than an outer diameter  324  of the lift tool  106 , and a second dimension  326  that extends perpendicular to the first dimension  322 . In one or more embodiments, the second dimension  326  is sized relative to the lift tool  106  and the insert device  116  within the lift tool  106  so that the locking member  302  is permitted to move relative to the lift tool  106 . In some embodiments, the second dimension  326  may be greater than the outer diameter  324 . In alternative embodiments, the second dimension  326  is substantially equal to or less than the outer diameter  324 . 
     The locking member  302  may be selectively movable with respect to the insert device  116  between a released position (shown in  FIGS. 9 and 10 ) and an engaged position (shown in  FIG. 11 ). In the released position, the insert device  116  is permitted to move through the shaft lumen  114  along the central axis  110  ( FIG. 1 ). In the engaged position shown in  FIG. 11 , the locking member  302  engages the insert device  116  and thereby holds the insert device  116  in a fixed position with respect to the locking member  302  and with respect to the lift tool  106 . The fixed position may be both a fixed axial position and a fixed rotational position. In such cases, the beveled end  141  ( FIG. 1 ) of the insert device  116  is fixed with respect to the distal end  108  ( FIG. 1 ) in a designated position and orientation. 
     In some embodiments, the engagement surface  308  is configured to increase friction between the insert device  116  and the engagement surface  308 . For example, the engagement surface  308  may include a rubber or elastic-like composition that partially conforms around the insert device  116  and grips the insert device  116 . 
     In some embodiments, the locking member  302  is held within the engaged position so that the operator may let go of the locking mechanism  124  without the locking member  302  returning to released position. The locking member  302  may form an interference fit with the shaft holder  304  or the lift tool  106 . By way of example, and with respect to  FIGS. 9 and 10 , the locking member  302  may include interference members  330  that are configured to engage the shaft holder  304 . In the released position, the interference members  330  may impede or resist movement of the locking member  302 . In the engaged position, the interference members  330  may resist movement of the locking member  302  back to the released position. In each of the released and engaged positions, the interference members  330  may provide a frictional force that resists movement of the locking member  302 . As such, an engagement force may be required from the operator to move the locking member  302  between the release and engaged positions. 
       FIGS. 12 and 13  illustrate side cross-sections of a locking mechanism  402  formed in accordance with one embodiment. The locking mechanism  402  is coupled to a lift tool  404  having a shaft lumen  406 . The lift tool  404  and the shaft lumen  406  may be aligned with respect to and extend along a central axis  415 . The locking mechanism  402  may be positioned proximate to a loading end  409  of the lift tool  404 . As shown, the locking mechanism  402  includes a locking member  410 , a shaft or tool holder  412 , and an operator-controlled movable body  414 . In the illustrated embodiment, the locking member  410  is an elastomeric member, such as an O-ring, that surrounds the lift tool  404 . The locking member  410  is configured to be moved by the movable body  414  with respect to an insert device  408  when the insert device  408  is located within the shaft lumen  406 . For example,  FIG. 12  shows the locking member  410  in a released position with respect to the insert device  408 , and  FIG. 13  shows the locking member  410  in an engaged position with respect to the insert device  408 . 
     The movable body  414  is configured to move bi-directionally along the central axis  415  to engage and disengage the locking member  410 . In the illustrated embodiment, the movable body  414  is rotatably engaged with the shaft holder  412 . As such, when the movable body  414  is rotated about the lift tool  404  in a first direction (e.g., clockwise), the movable body  414  is driven toward the locking member  410 . When the movable body  414  is rotated about the lift tool  404  in a second direction (e.g., counter-clockwise), the movable body  414  is driven away from the locking member  410 . However, in alternative embodiments, the movable body  414  may not be rotatable. For example, the movable body  414  may instead be slidable bi-directionally along the lift tool  404 . 
     As shown, the movable body  414  includes a mating end  416  having an outer surface  418 . The mating end  416  is disposed within a receiving cavity  420  of the shaft holder  412 . More specifically, the shaft holder  412  includes an interior surface  422  that defines the receiving cavity  420  and includes a portion that faces the outer surface  418 . In the illustrated embodiment, the outer surface  418  and the interior surface  422  include threads  424 ,  426 , respectively. The threads  424 ,  426  engage each other and are configured to move the movable body  414  toward (or away) from the shaft holder  412  when the movable body  414  is rotated. 
     The mating end  416  may include a mating surface  430  that is shaped to at least partially face the insert device  408  and/or the lift tool  404 . For example, the mating surface  430  may be shaped conically and surround the central axis  415 . In such embodiments, as the movable body  414  is driven toward the shaft holder  412 , the mating surface  430  engages the locking member  410 . At this time, the locking member  410  may also be pressed against a member-engaging portion  428  of the interior surface  422 . As the movable body  414  continues to move toward the shaft holder  412 , the locking member  410  is displaced toward the central axis  415  and pressed against the insert device  408 . An engagement force at which the locking member  410  is pressed against the insert device  408  may effectively hold the insert device  408  in a fixed position. 
     As such, the locking mechanism  402  is configured to selectively move the locking member  410  with respect to the insert device  408  between a released position and an engaged position. When the movable body  414  is not engaging the locking member  410 , the locking member  410  is in the released position and may be spaced apart from the insert device  408  as shown in  FIG. 12 . The insert device  408  may be permitted to move axially and rotatably within the shaft lumen  406 . In the engaged position, the Insert device  116  may have a fixed axial location and a fixed rotational position. 
       FIGS. 14 and 15  illustrate side cross-sections of a locking mechanism  502  formed in accordance with one embodiment. The locking mechanism  502  is coupled to a lift tool  504  having a shaft lumen  506 . As shown, the locking mechanism  502  includes a locking member  510 , a shaft or tool holder  512 , and an operator-controlled movable body  514 . The shaft holder  512  may be in a fixed position with respect to the lift tool  504  and provide support for the movable body  514 . The movable body  514  is configured to be rotated by the operator about an axis of rotation that extends into and out of the page in  FIGS. 14 and 15 . For example, the movable body  514  may be rotatable about an axle  516  to move the movable body  514  between released and engaged positions. 
       FIG. 14  shows the locking member  510  in a released position with respect to the insert device  508 , and  FIG. 15  shows the locking member  510  in an engaged position with respect to the insert device  508 . For each of the released and engaged positions, interference members (not shown) may hold the movable body  514  in the respective position such that a force (e.g., from the operator) is required to move the movable body  514  to a different position. In the illustrated embodiment, the locking member  510  is a portion of movable body  514 . As such, when the movable body  514  is moved by the operator with respect to the insert device  508 , the locking member  510  moves with the movable body  514 . 
     As shown in  FIGS. 14 and 15 , when the movable body  514  is rotated about the axle  516  from the released position to the engaged position, the locking member  510  is received into the shaft lumen  506  through a lock opening  518  of the lift tool  504  and directly engages the insert device  508  therein. The engagement between the locking member  510  and the insert device  508  may create frictional forces that hold the insert device  508  in a fixed position. 
     In an alternative embodiment, the locking mechanism  502  may include an O-ring that surrounds the lift tool  504  in a similar manner as the locking member  410  surrounds the lift tool  404  in  FIGS. 12 and 13 . In this alternative embodiment, the movable body  514  may press into the O-ring and thereby push the O-ring through the lock opening and against the insert device  508 . 
       FIGS. 16 and 17  are images of medical devices  540 ,  560 , respectively, that are each formed in accordance with one embodiment. The medical device  540  includes a lift tool  542 , a torque applicator  544 , and a locking mechanism  546 . The medical device  560  includes a lift tool  562 , a torque applicator  564 , and a locking mechanism  566 . Each of the lift tools  542 ,  562 , the torque applicators  544 ,  564 , and the locking mechanisms  546 ,  566  may include one or more of the features of the lift tools, torque applicators, and locking mechanisms described herein. For example, the locking mechanisms  546 ,  566  may be similar or identical to the locking mechanisms  502 ,  124 , respectively. The torque applicators  544 ,  564  may be similar or identical to the torque applicator  122 . 
     Also shown in  FIGS. 16 and 17 , the medical devices  540 ,  560  are holding an insert device  550  that includes a Lure lock  552  and a Tuohy needle  554 . The Lure lock  552  is configured to engage an end of the Tuohy needle  554  and facilitate insertion of objects through the Tuohy needle  554 . The Luer lock  552  is also shaped to interface with a respective loading end of the lift tool. Also shown, the lift tool  542 ,  562  have projections  556  (e.g., tines) at the respective distal ends  543 ,  563 . The projections  556  are configured to be embedded into an anatomic layer, such as the parietal pericardium. Object ends  558  of the Tuohy needles  554  are also shown clearing the distal ends  543 ,  563 . 
       FIG. 18  is a flowchart illustrating a method  600  of accessing an anatomic space in accordance with one embodiment. The method  600  is described with specific reference to the anatomic space being the pericardial space that is defined by the parietal pericardium. However, it is understood that the method  600  may be similarly implemented with other anatomical spaces and anatomic layers. The method  600  may include forming, at  602 , an incision in the skin of an individual. In certain embodiments in which it is desired to access the pericardial space, the incision may be located just below the xiphoid process. At  604 , a lift tool of a medical device may be inserted through the incision. For example, the lift tool may be inserted through the tissues between the subxiphoid wound and the pericardium. In embodiments that include lift tools with projections or tines for gripping tissue, the lift tool may have an obturator that extends beyond the distal end of the lift tool. More specifically, an end of the obturator may clear the distal end of the lift tool and the projections. The obturator may prevent coring in which unwanted fluid or other material flows into the shaft lumen as the lift tool is inserted into the body. Moreover, the obturator may reduce the likelihood of the projections inadvertently snagging tissue. 
     The lift tool may be inserted until the distal end interfaces with or engages an anatomic layer. By way of example, the operator may insert the lift tool into the body until the operator detects or senses the heart. More specifically, the operator may be able to detect movement of the heart muscle (e.g., contractions) through a handle of the medical device. 
     At  606 , the distal end of the lift tool may be operatively engaged to the anatomic layer. For embodiments that include projections at the distal end, the lift tool may be rotated about a central axis of the lift tool while force is maintained in the Insertion direction to embed the projections into the anatomic layer. As described herein, the projections may be shaped (e.g., curved) to pierce and extend into the anatomic layer as the lift tool is rotated. In alternative embodiments, the engagement operation  606  may include generating a vacuum within the shaft lumen to draw a portion (e.g., bleb) of the anatomic layer into the distal end of the lift tool. 
     One or more of the medical devices used during the method  600  may include a torque applicator and/or a locking mechanism, such as the torque applicators and locking mechanisms described herein. 
     In certain embodiments, the torque applicator is used after the lift tool has engaged the anatomic layer. For example, the method  600  may include rotating, at  608 , a movable body of the torque applicator about the lift tool. The movable body may be operatively coupled to the lift tool through a biasing member. When the movable body is rotated in a coupling direction, a potential energy in the biasing member is increased to thereby provide a rotational force for maintaining the operative engagement. By way of example only, the movable body may be rotated clockwise ¼ to ½ turn to put a slight torque bias on the projections to maintain engagement with the pericardial tissue. 
     Optionally, the torque applicator may also be used to operatively engage, at  606 , the lift tool to the anatomic layer. For example, the biasing member may provide a sufficient rotational force for the projections to pierce the anatomic layer and become embedded in the anatomic layer. In other embodiments, the operations  606 ,  608  may be caused by separate strokes (e.g., rotations) of the operator or may be caused by the same stroke from the operator. For example, rotating the movable body may cause the lift tool to engage the anatomic layer and may also cause a change in the potential energy of the biasing member. 
     In some cases, multiple biasing members may be used that have different potential energies. For example, first and second biasing members may be used to provide sufficient force for piercing the anatomic layer. After the distal end is operatively engaged, the first biasing member may be released and the second biasing member may remain. In some cases, the second biasing member may provide a different rotational force than the first biasing member. 
     Optionally, an insert device may be removed, at  610 , from the lift tool. For example, for those embodiments that utilize an obturator as the lift tool is inserted into the body, the obturator may be removed. At  612 , a second insert device may be inserted into the shaft lumen. For example, a Tuohy needle may be inserted into the lift tool and advanced toward the anatomic layer. In some embodiments, the Tuohy needle may include an obturator within the lumen of the needle. 
     Optionally, at  614 , the anatomic layer may be drawn away or retracted to enlarge the anatomical space located behind the anatomic layer. In the case of cardiac procedures, retracting the parietal pericardium (e.g., “tenting” the parietal pericardium) enlarges the pericardial space in order to reduce the likelihood of the Tuohy needle puncturing heart tissue behind the parietal pericardium. 
     At  616 , a distal end of the insert device may be inserted through the anatomic layer. For example, the Tuohy needle may be inserted through the lift tool until it is detected at a Luer-lock end that the distal end of the Tuohy is pressing against the pericardial tissue. The distal end of the Tuohy needle may then be inserted through the tented parietal pericardium to access the pericardial space. 
     After the insert device is inserted through the anatomic layer, the insert device may be locked, at  618 , into a fixed position. For example, the method  600  may include utilizing a locking mechanism, such as those described herein, to hold the insert device in a fixed axial location and in a fixed rotational position. 
     At  620 , a third insert device is inserted into the lift tool. For example, a guidewire may be inserted into the Tuohy needle. In some embodiments, the Tuohy needle has an obturator when the Tuohy needle is inserted into the lift tool. Accordingly, prior to the insertion operation at  620 , the method may include removing one or more of the insert devices already present in the shaft lumen. More specifically, the method may include removing the obturator of the Tuohy needle. 
     With the obturator removed, the guidewire may then be inserted into the Tuohy needle, through the distal end of the lift tool, and into the pericardial space. At  622 , the medical device may then be removed by sliding the medical device (e.g., the lift tool and any insert device other than the guidewire) along the guidewire. The operator or other qualified individual may then proceed with using the guidewire in the pericardial space. 
     It is to be understood that the subject matter described herein is not limited in its application to the details of construction and the arrangement of components set forth in the description herein or illustrated in the drawings hereof. The subject matter described herein is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the elements listed thereafter and equivalents thereof as well as additional elements. 
     Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. Also, it is to be understood that phraseology and terminology used herein with reference to device or element orientation (such as, for example, terms like “central,” “upper,” “lower,” “front,” “rear,” “distal,” “proximal,” and the like) are only used to simplify description of one or more embodiments described herein, and do not alone indicate or imply that the device or element referred to must have a particular orientation. In addition, terms such as “outer” and “inner” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance. 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the presently described subject matter without departing from its scope. While the dimensions, types of materials and coatings described herein are intended to define the parameters of the disclosed subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the inventive subject matter should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure. 
     Although the inventive subject matter has been described with reference to certain embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.