Patent Publication Number: US-9883910-B2

Title: Hand held surgical device for manipulating an internal magnet assembly within a patient

Description:
PRIORITY 
     This application is a continuation application filed under 35 U.S.C. § 120 of U.S. application Ser. No. 13/420,805 filed Mar. 15, 2012 and entitled “Hand Held Surgical Device for Manipulating an Internal Magnet Assembly Within a Patient,” which application has matured into U.S. Pat. No. 9,049,987, the contents of which are incorporated herein by reference in their entirety and for all purposes; this application also claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No. 61/453,824 filed Mar. 17, 2011, the contents of which are incorporated herein by reference in their entirety. 
    
    
     PARTIES TO A JOINT RESEARCH AGREEMENT 
     Ethicon Endo-Surgery, Inc., an Ohio corporation, and Southwestern Medical Center at Dallas having a place of business at 5323 Harry Hines Blvd, Dallas, Tex. 75390, are parties to a Joint Research Agreement. 
     Ethicon Endo-Surgery, Inc., an Ohio corporation, and The University of Texas at Arlington having a place of business at 710 S. Nedderman Drive, Arlington, Tex. 76019, are parties to a Joint Research Agreement. 
     BACKGROUND 
     i. Field of the Invention 
     The present application relates to methods and devices for minimally invasive therapeutic, diagnostic, or surgical procedures and, more particularly, to magnetic guidance systems for use in minimally invasive procedures. 
     ii. Description of the Related Art 
     In a minimally invasive therapeutic, diagnostic, and surgical procedures, such as laparoscopic surgery, a surgeon may place one or more small ports into a patient&#39;s abdomen to gain access into the abdominal cavity of the patient. A surgeon may use, for example, a port for insufflating the abdominal cavity to create space, a port for introducing a laparoscope for viewing, and a number of other ports for introducing surgical instruments for operating on tissue. Other minimally invasive procedures include natural orifice transluminal endoscopic surgery (NOTES) wherein surgical instruments and viewing devices are introduced into a patient&#39;s body through, for example, the mouth, nose, or rectum. The benefits of minimally invasive procedures compared to open surgery procedures for treating certain types of wounds and diseases are now well-known to include faster recovery time and less pain for the patient, better outcomes, and lower overall costs. 
     Magnetic anchoring and guidance systems (MAGS) have been developed for use in minimally invasive procedures. MAGS include an internal device attached in some manner to a surgical instrument, laparoscope or other camera or viewing device, and an external hand held device for controlling the movement of the internal device. Each of the external and internal devices has magnets which are magnetically coupled to each other across, for example, a patient&#39;s abdominal wall. In the current systems, the external magnet may be adjusted by varying the height of the external magnet. 
     The foregoing discussion is intended only to illustrate various aspects of the related art in the field of the invention at the time, and should not be taken as a disavowal of claim scope. 
     SUMMARY 
     A device is described herein for manipulating a magnetic coupling force across tissue based on the monitored coupling force generated between the external and internal magnets. In one embodiment, the device includes a magnetic field source assembly that comprises a first magnetic field source for providing a magnetic field across tissue. The first magnetic field provides a magnetic coupling force between the first magnetic field source and an object that provides a second magnetic field. The device also includes a positioning assembly operatively connected to the magnetic field force assembly for adjusting the position of the first magnetic field source, and a magnetic coupling force monitor. 
     The device may further include an outer housing that contains the magnetic field source assembly and preferably also contains at least a portion of the positioning assembly. In certain embodiments, the positioning assembly includes a driver for adjusting the elevational position of the magnetic field force assembly within the outer housing, and an actuator for moving the driver. 
     In several embodiments, the magnetic field source assembly may comprise a first magnetic field source for providing, in use, a magnetic field across tissue, the first magnetic field providing a magnetic coupling force between the first magnetic field source and an object providing a second magnetic field source; a positioning assembly operatively connected to the magnetic field force assembly for adjusting the position of the first magnetic field source, the positioning assembly having a driver for adjusting the elevational position of the magnetic field force assembly and an actuator for moving the driver; and a magnetic coupling force monitor. 
     In certain embodiments of the device, the object is structured for positioning in use on an internal site of a patient and has associated therewith a second magnetic field source for forming with the first magnetic field source the magnetic coupling force across tissue. 
     The magnetic field source assembly may further include a magnet housing and a magnet support. In certain embodiments, first magnetic field source may have at least one magnet and preferably two magnets, held by the magnet support and suspended within the magnet housing. A bracket member may be provided for connecting the magnet housing to the driver of the positioning assembly. Movement of the driver will adjust the elevational position of the magnet housing within the outer housing. 
     In one embodiment, the actuator of the positioning assembly may be a manually controllable actuator operatively connected to the driver. For example, the manually controllable actuator may be a rotatable knob mounted on a proximal end of the driver which, when turned, rotates the driver to adjust the elevational position of the magnet housing. 
     Some embodiments of the device may include a spring assembly for suspending the magnet and magnet support within the magnet housing. The spring assembly may include a spring mounted at its distal end on the magnet support and operatively suspended at its proximal end from the magnet housing, and biased toward the proximal end thereof. 
     In certain embodiments, the spring assembly may also include a retainer connected through the bracket to the magnet housing and a suspension member connected to the magnet support. The retainer is preferably structured to secure thereto the proximal end of the spring and the suspension member is preferably structured to secure thereto the distal end of the spring. 
     In certain embodiments, the suspension member is operatively connected to the magnetic coupling force monitor. The magnet housing may define a first window therethrough and the outer housing may define a second window therethrough aligned with the first window. In certain embodiments, the magnetic coupling force monitor may comprise an indicator tab that extends from the suspension element through, and is movable up and down, in a proximal or distal direction, within, each of the first and second windows. Indicia may be marked on an exterior surface of the outer housing adjacent the second window indicative of the coupling force experienced by the magnet. 
     Some embodiments of the actuator may include a gear set operatively connected to the driver and a motor operatively connected to the gear set for motorized control of the driver. 
     The device may be provided with an electromechanical automatically adjusting closed loop system for controlling the magnetic coupling force based on the sensed force between the external and internal magnetic field sources. 
     Certain embodiments of the magnetic coupling force monitor may include a sensor positioned at a distal end of the magnet support on which the magnet support rests. The sensor is preferably calibrated to sense any change in the force exerted on the sensor. A communication circuit is preferably provided from the sensor to the motor to control the operation of the motor in response to the sensed changes in force. 
     The magnetic coupling force monitor may further include a transducer positioned on the floor of the magnet housing for measuring changes in the magnetic coupling force between the magnet and the object and transmitting signals representative of the measured change in the magnetic coupling force; a control unit for receiving the signals from the transducer; and, a processor in communication with the control unit for converting the received signals to output signals for signaling the motor to adjust the elevation of the magnet housing until a predetermined magnetic coupling force is measured by the transducer. 
     The positioning assembly may also include a fail-safe mechanism for preventing travel of the driver outside of predetermined limits. The fail-safe mechanism may be an optical sensor having a channel, a light source for sending a beam of light across the channel, a light blocking member structured for passage through the channel and operatively connected to the magnetic field source assembly, and a receiver for detecting the presence or absence of the beam of light across the channel and for signaling the presence or absence of the beam of light to the motor to stop the motor when the beam of light is blocked by the blocking member. 
     The fail-safe mechanism may alternatively be a set of trip switches for signaling the motor to stop when the driver travels outside of the predetermined limit. 
    
    
     
       FIGURES 
       Various features of the embodiments described herein are set forth with particularity in the appended claims. The various embodiments, however, both as to organization and methods of operation, together with advantages thereof, may be understood in accordance with the following description taken in conjunction with the accompanying drawings as follows. 
         FIG. 1  is a view of the front of an embodiment of the manually controllable hand held manipulation device. 
         FIG. 2  is a view of some internal components of the embodiment of  FIG. 1  through a transparent outer housing. 
         FIG. 3A , is a perspective view of the top of an embodiment of the magnetic field source assembly. 
         FIG. 3B  is a perspective view of the bottom of an embodiment of the magnetic field source assembly 
         FIG. 3C  is a perspective view of the partial interior of an embodiment of the magnetic field source assembly. 
         FIG. 4  is a perspective view of the bottom of an embodiment of the magnets and magnet support of the assembly of  FIG. 3B . 
         FIG. 5  is a perspective view of the magnetic field source assembly with a portion of the drive assembly and the magnetic coupling force monitor. 
         FIG. 6  is a perspective view into the interior of the embodiment of the manually controllable hand held manipulation device of  FIG. 1 , with the cover removed. 
         FIG. 7  is a view of the spring and indicator in the manually controllable hand held manipulation device. 
         FIG. 8A  is a partial section view of the spring and indicator through the line A-A of  FIG. 5 . 
         FIG. 8B  is a partial section view of the spring and indicator through the line B-B of  FIG. 5 . 
         FIG. 9  is a perspective view of an embodiment of an automatic hand held manipulation device with a transparent outer housing to show some internal components of the automatic hand held manipulation device. 
         FIG. 10  is a front view of the embodiment of  FIG. 9  with a transparent outer housing. 
         FIG. 11  is a view of an embodiment of an optical fail-safe mechanism of the embodiment of  FIGS. 9 and 10 . 
         FIG. 12  is a schematic view of components of an embodiment of a sensor system usable in the hand held manipulation device. 
         FIG. 13  is a section view of the device of  FIG. 9 . 
         FIG. 14  is a front view of the magnetic field source assembly of  FIGS. 9 and 10 , with a transparent magnet housing. 
         FIG. 15  is a front view of an alternative embodiment of an automatic hand held manipulation device with a transparent outer housing to show internal components. 
         FIG. 16  is a side view of the embodiment of  FIG. 15 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate various embodiments of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DESCRIPTION 
     Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, the scope of which is defined solely by the appended claims. 
     In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below. 
     Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment”, or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment”, or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features structures, or characteristics of one or more other embodiments without limitation. 
     It will be appreciated that the terms “proximal” and “distal” may be used throughout the specification with reference to a clinician manipulating one end of an instrument used to treat a patient. The term “proximal” refers to the portion of the instrument closest to the clinician and the term “distal” refers to the portion located farthest from the clinician. It will be further appreciated that for conciseness and clarity, spatial terms such as “vertical,” “horizontal,” “up,” and “down” may be used herein with respect to the illustrated embodiments. However, surgical instruments may be used in many orientations and positions, and these terms are not intended to be limiting and absolute. 
     As used herein, the term “elevational position” with respect to one or more components means the distance of such component or components above a floor or ground or bottom position of another component or reference point without regard to the spatial orientation of the respective components. 
     As used herein, the term “biocompatible” includes any material that is compatible with the living tissues and system(s) of a patient by not being substantially toxic or injurious and not known to cause immunological rejection. “Biocompatibility” includes the tendency of a material to be biocompatible. 
     As used herein, the term “operatively connected” with respect to two or more components, means that operation of, movement of, or some action of one component brings about, directly or indirectly, an operation, movement or reaction in the other component or components. Components that are operatively connected may be directly connected, may be indirectly connected to each other with one or more additional components interposed between the two, or may not be connected at all, but within a position such that the operation of, movement of, or action of one component effects an operation, movement, or reaction in the other component in a causal manner. 
     As used herein, the term “operatively suspended” with respect to two or more components, means that one component may directly suspended from another component or may be indirectly suspended from another component with one or more additional components interposed between the two. 
     As used herein, the term “patient” refers to any human or animal on which a suturing procedure may be performed. As used herein, the term “internal site” of a patient means a lumen, body cavity or other location in a patient&#39;s body including, without limitation, sites accessible through natural orifices or through incisions. 
     The manipulation device  10  is structured to manipulate a magnetic coupling force across living tissue  200  between objects having, or associated with, magnetic fields. The manipulation device  10  generally includes a magnetic field source assembly  24 , a positioning assembly operatively connected to the magnetic field source assembly, and a magnetic coupling force monitor. 
     The magnetic field source assembly  24  includes a first, or external, magnetic field source that provides a magnetic field across tissue  200 . In MAGS applications, there is an object  210 , as shown in  FIG. 1 , positioned in use on an internal site of a patient, across the tissue  200  (e.g., the abdominal wall or other tissue barrier between the inside and the outside of the patient) from the manipulation device  10 . The internal object  210  is itself or is operatively connected to another component that is a source of a second, or internal, magnetic field. The first, or external, magnetic field of the magnetic field source assembly  24  and the second, or internal, magnetic field source create a magnetic coupling force wherein the internal object  210  is magnetically coupled across the tissue  200  to the magnetic field source of the manipulation device  10 . 
     Lateral movement of the manipulation device  10  over the external surface of the tissue  200  causes a similar lateral movement of the internal object  210  on the internal surface of the tissue. If the magnetic coupling force is too strong, however, lateral movement may be difficult due to the resistance to movement by the strongly attracted, magnetically coupled objects, or may induce tissue trauma due to the high coupling force. Based on the monitored force generated between the external and internal magnetic field sources, the manipulation device  10  described herein enables control of the magnetic coupling force to maintain the force at a level that is strong enough to hold the internal object  210  while allowing lateral movement of the manipulation device  10  and the internal object, but without inducing excess tissue trauma. 
     The control that the manipulation device  10  exercises over the magnetic coupling force may be manual or automatic. In each embodiment, the manipulation device  10  may include a magnetic field source assembly  24  that is suspended within an outer container  12  that provides an outer housing for the device  10 . The magnetic assembly  24  is raised and lowered, either automatically in response to a sensor, or manually in response to a clinician&#39;s control, to adjust the power that the external magnetic field source exerts over the internal object and its associated internal magnetic field source. Adjusting the power of the external magnetic field adjusts the magnetic coupling force between the external magnetic assembly and the internal object. 
     Referring to  FIGS. 3A-C , the magnetic field source assembly  24  includes generally a magnet housing  26  having side walls  26   a  and a bottom cross bar  26   b , at least one or more, and preferably two magnets  28 , and a magnet support  36 . The magnet support  36  includes front and rear panels  48  and a midsection  50  that separates the magnets  28 . The support  36  is fixed to each magnet  28  by any suitable engagement members. For example, referring to the embodiment of  FIG. 4 , raised rails  58  are positioned in complementary engagement with recessed tracks  60  formed on at least a portion of facing surfaces of the front and rear panels  48  and magnets  28 , respectively. Those skilled in the art will appreciate that the magnets  28  may have raised surfaces and the support  36  may have complementary recessed surfaces to secure the magnets  28  within support  36 . Other suitable complementary engagement surfaces or other suitable fixation devices to secure the magnets  28  to the support  36  will suffice. 
     Spacers  66  extend from the support panels  48  to maintain alignment of the magnets  28  within support  36 . 
     The midsection  50  of support  36  is structured in certain embodiments to define a lower channel  52  between the lower ends of magnets  28  forming an open space between the cross-bar  26   b , midsection  50 , and the interior facing sides  62  of magnets  28 . The midsection  50  also defines an upper channel  54  between the top ends of magnets  28  forming an open space between the top of midsection  50  and the interior facing sides  62  of magnets  28 . As shown in  FIG. 3 , a well  64  may be formed in the top of midsection  50 . 
       FIGS. 5-8  illustrate an embodiment of the magnetic assembly  24  having a bracket  40  connected to magnet housing  26 . The bracket  40  shown in the figures includes a top section  80  and a central post  78  that extends partially into the channel  54  between magnets  28 . Extending downwardly from post  78  on opposing sides of post  78  are bracket legs  82 . A flange  68  extends from each side of the top section  80  of bracket  40  to seat in a chamfer on the upper edge of magnet housing  26  to hold bracket  40  in position relative to magnet housing  26 . Pins  86  protrude laterally from each side of central leg  82  through pin holes  90  in magnet housing side walls  26   a  to further fix bracket  40  to magnet housing  26 . 
     The positioning assembly may include a drive shaft  88  which extends through a bore  84  in top  80  of bracket  40 . In this embodiment, bore  84  and drive shaft  88  are preferably threaded so that actuation of the drive shaft  88  carries bracket  40 , and with it, magnet housing  26  up and down within the open gap  46  in outer housing  12  between the top of the magnet assembly  24  and the bottom of shaft head  74 . 
     In certain embodiments, the position of the magnet housing  26  may be adjusted manually by the surgeon or clinician. A spring loaded scale may be used to float the magnets  28  within the housing  26  and to monitor the magnetic coupling force. Referring to  FIGS. 7 and 8A , B, a retainer  94  sits in and is fixedly attached to well  64  of magnet support  36 . A spring  92  is positioned on the boss of retainer  94  that extends upwardly into channel  54  between magnets  28 . The top of spring  92  is press fit onto a retainer  96  that is suspended from pins  98 . Pins  98  protrude laterally from each side of retainer  96  and extend into and through pin holes  76  in bracket legs  82  of bracket  40  and magnet housing  26  to fix retainer  96  to bracket  40  and magnet housing  26 . The magnets  28  and magnet support  36  are thus suspended by spring  92  within magnet housing  26 , allowing the magnets  28  to float above the floor of outer housing  12 . The magnet support  36  and magnets  28  are not fixedly attached to magnet housing  26  or to bracket  40 , but move up and down within magnet housing  26 . Support  36  and magnets  28  are dimensioned to be smaller than magnetic housing  26  to fit within magnet housing  26  such that a gap  44  is created between the floor of outer housing  12  and the bottom surface of magnets  28  and the magnets  28  move freely without resistance from the interior walls of magnet housing  26 . 
     Referring to  FIG. 1 , the manipulation device  10  includes outer housing  12  having a top cover  14 . The sides of cover  14  include openings  20  to expose a knob  16 . The cover  14  may be connected to outer housing  12  in any suitable manner, such as with pins or screws  38  or a similar fastener, through pin holes or threaded bores  70 , shown in  FIG. 6 . As shown in  FIG. 6 , outer housing  12  includes cut-out sections  72  on the top edge to accommodate portions of knob  16 . The knob  16  may be turned in a clockwise or a counter clockwise direction by placing a hand on the top of cover  14  and turning knob  16  with the thumb of the hand through openings  20 . Knob  16  may include ridges  18  or any suitable textured surface along its circumference to facilitate tactile control over the movement of knob  16 . Knob  16  is operatively connected to drive shaft  88  by a shaft head  74  that is sized to engage a complementary mating surface on knob  16 . 
     A magnetic coupling force monitor is provided in one embodiment of the manipulation device  10  by means of an indicator bar  32  that extends laterally from retainer  94  through windows  100  and  30  in magnet housing  26  and outer housing  12 , respectively. Indicia  34  in the form of markings may be positioned on the outer surface of outer housing  12  adjacent window  30  to represent the position of magnets  28  within magnet housing  26  and outer housing  12 . The indicia are calibrated to represent predetermined loads on the magnets  28 , representative of the magnetic coupling force across a patient&#39;s tissue between the external magnets  28  and one or more internal magnets associated with an internal object. For example, the force of gravity on the external magnets pulling the magnets  28  toward the floor of magnet housing  26  is zeroed out so that the force reflected by the indicia  34  represent only the magnetic coupling force. A force that could cause trauma to the tissue might be indicated by one of the lower markings or the lowest marking whereas a force that would be insufficient to hold the internal object in place might be indicated by one of the higher markings or the highest marking. 
     The clinician may observe the level of the magnetic coupling force by the position of the indicator bar  32  with respect to the markings  34 . If the level of the coupling force is too high or too low, the clinician will adjust the knob  16  in a clockwise or counter clockwise direction to raise or lower the magnet housing  26  within the outer housing  12 . As the elevational position of magnet housing  26  within outer housing  12  is changed up or down, the elevational position of magnets  28  changes up or down as well, subject to deviations within magnet housing  26  due to the magnetic coupling force exerted on magnets  28 . Because of the suspension of the magnet support  36  and magnets  28  within magnet housing  26  and the clearance or gap  44  between the bottom of the magnets and the floor of the outer housing  12 , the magnet support  36  and magnets  28  float within housing  26 , so the only force measured is the magnetic coupling force of the magnets  28 . The gap  44  may be relatively small, for example, about 5 mm, but must allow enough space so that the magnets  28  are free to move in response to the magnetic attraction from the second magnetic field source associated with the internal object in the patient. The spring  92  is biased toward the retainer  96 , so, after accounting for gravity, the magnetic coupling force is the force pulling the magnets  28  downwardly, in the distal direction. 
     In certain embodiments, the positioning assembly may be automatic. In certain automated embodiments, as shown for example in  FIGS. 9 through 11 and 13 , the positioning assembly includes a shaft  88 , preferably a screw drive, a drive gear  102 , and a pinion gear  104 . The pinion gear  104  is attached to the drive gear  102 . A motor  106  drives the pinion gear  104  which drives the drive gear  102 , which turns the shaft  88  to raise and lower the magnetic field source assembly  24 . The drive gear  102  is attached to shaft  88  and is supported on thrust bearings  142 . The shaft  88  is attached to bracket  40 , as described above. In the automated embodiment, the bracket  40  is attached to the magnet housing  26  as described above, so turning shaft  88  raises and lowers the magnet housing  26  within outer housing  12 . Whether the magnet housing  26  is raised or lowered, the magnet set still floats within the magnet housing  26  so the magnet  28  can respond to any magnetic pull exerted by the internal magnetic field source within the patient. 
     In the automated embodiments, as shown for example, in  FIGS. 10, 13 and 14 , a sensor  116  is positioned within the magnet housing  26 , fixed to cross-bar  26   b  of the housing  26  in channel  54 . The sensor  116  may be, for example, a transducer, a piezoelectric film sensor, or a load cell. The bottom surface of mid section  50  of magnet support  36  rests on the sensor  116 . In use, the magnetic force of the internal magnetic field source attracts the magnets  28  in the external manipulation device  10 . The magnetic coupling force pulls the magnets  28  against the sensor  116 . The sensor  116  senses the force and communicates the sensed force to a control unit  120 . Magnetic field lines are established by the magnetic field between the external and internal magnets, pulling the magnets in the magnet housing  26  down, toward the internal magnets on the object within the patient. As the downward pull increases, it pulls the magnetic support  36  harder against the sensor  116 , causing the sensor  116  to measure and register a greater force against it. The sensor  116  signals the calculated force back to the control unit  120  wirelessly or via circuitry, such as wire  154  or  114 . The sensor  116  is adjusted to have a zero point accounting for gravity plus the weight of the magnet housing  26 , magnets  28 , and magnet support  36 . 
     Those skilled in the art will appreciate that other types of sensors may be used. A LCD screen may be provided to show the force generation between the internal and external magnets. 
     If sensor  116  is a load cell type of sensor, for example, it feeds the load signal to a signal conditioner. The load cell  116  is acted upon by the attractive forces between the internal and the external magnets. The load cell  116  strains internally and the resulting strain is measured in terms of electrical resistance, using current provided by any suitable power supply. The signal conditioner, which may be contained within the control unit  120 , amplifies the signal from the load cell and then a suitable algorithm may be used to calculate the actual force which is then used to drive the motor  106  at a calculated speed and duration to adjust the force. 
     The signal is sent by the sensor  116  to the control unit  120  which is equipped with a receiver to receive the signals and where software analyzes the received signals, and sends output signals to instruct the motor  106 , such as a stepper type motor, to drive the drive shaft  88 , which moves the magnet housing  26  up or down sufficiently to match a predetermined force. When the predetermined force is sensed by sensor  116 , the sensed signals are communicated to the control unit  120  which, as before, instructs the motor  106  to stop. The continuous monitoring in use of the magnetic coupling force provides an automatic closed loop feedback system to control the magnetic coupling force. The power supply and control unit  120  may be on any suitable printed circuit board and packaged within the outer housing  12  of the manipulation device  10 .  FIG. 12  shows a schematic of the power supply  118  to a transducer  116  and the signals to and from the control unit  120 . 
     The predetermined force will be the minimum force that necessary to attract and accurately control the internal object carried by the internal magnet. The internal magnet must be held with enough magnetic force to prevent it from falling away from the internal body wall. The maximum amount of force would be less than a force that compresses or squeezes the tissue enough to cause tissue trauma. The surgeon has to be able to move the external magnet relatively easily across the patient&#39;s body to control the internal magnet without so much drag that movement is difficult or would cause tissue trauma. 
     The device  10  preferably includes a fail safe mechanism to prevent the motor  106  from moving the magnet housing  26  up or down too far. The device  10  may, for example, include an optical sensor  108 , shown in  FIGS. 9-11 . The optical sensor  108  has a slot  132  through at least a portion thereof dividing the sensor into two parts, a light source portion  136  and a receiver portion  134 . A light emitting diode (LED) resides in light source portion  136  of the optical sensor  108  and a receiver resides in the receiver portion  134 . Light is generated inside the optical sensor  108  by the LED and beamed across the slot  132  through a light path  138  to the receiver portion  134 . Pin connectors  112  from the optical sensor  108  plug into the circuit board  150 , or wires may go to a printed circuit board which contains the hardware for running the sensor  116  and power sensors. A flag  110  has one end attached to the bracket  40  so that it moves up and down with the magnet housing  26  and has a second end having a top cross bar  130  that passes through the slot  132  of the optical sensor  108  as the flag moves up and down. A post  140  joining the first end to second end defines an open section between the two ends. When the flag  110  is positioned such that the top cross bar  130  of the second end blocks the path  138  for the beam of light from the LED to the receiver, the signals to the software on the circuit board  150  through connectors  112  or wires are interrupted causing the motor  106  to stop, thereby stopping the downward movement of the drive shaft  88  and the magnet housing  26 . The magnet housing  26  is prevented from pressing against the bottom of the outer housing  12 . When the flag  110  is positioned such that the top cross bar  130  of the second end is above the path  138  of the beam of light, the beam of light passes through the opening in the flag to the receiver in the receiver portion  134  of the optical sensor  108 , which in turn signals the motor  106  through the circuit board  150  to drive the magnet housing  26  up or down. 
     After the motor  106  stops because the beam of light is blocked, the motor  106  will start again only when the sensor  116  signals that the force against the sensor  116  has been reduced. If the magnetic pull on the magnets  28  is reduced, the sensor  116  will sense the change and signal the control unit  120 . The software logic will restart the motor  106  to allow the drive shaft  88  to move the magnet housing  26  up. The movement of the magnet housing  26  brings the flag  110  up with it, moving the top cross bar  130  of the second end above the light path and opening in the light path. If the magnet housing  26  rises too far, the first end of the flag will block the light path and in turn cause the motor  106  to stop. The magnet housing  26  is prevented from going up too far against the top of the outer housing  12 . 
     The optical sensor  108  is fixed to a spacer piece and sits in a fixed position within a pocket in the outer housing  12  above the magnet housing  26 . Those skilled in the art will recognize that other types of optical sensors and other types of fail safe mechanisms, including but not limited to trip switches, may be used. 
     Another embodiment of the automated manipulation device is shown in  FIGS. 15 and 16 . The motor  106 ′ of the positioning assembly in this embodiment is positioned beside the magnet housing  26  rather than above it, as shown in  FIGS. 9-11 . The motor  106 ′ is connected by a shaft  104 ′ to a pinion gear  102 ′ which turns a ring gear  152 . A screw drive  88 ′ is operatively connected to the ring gear  152 . 
     A sensor  116 ′, such as a piezo electric pressure sensitive film, is positioned on the floor of the outer housing  12 ′ beneath the magnet housing  26 ′. The sensor  116 ′ is electrically connected to a printed circuit board  120 ′ by wire  154 . The circuit board  120 ′ may utilize a programmable controller (e.g., EPROM) to analyze signals from the sensor  116 ′, in the manner generally described above. The circuit board  120 ′ is also electrically connected to a pressure transducer  160  positioned beneath the cover  14 ′ of the outer housing  12 ′. In order to isolate the force applied by the clinician on the cover  14 ′ of outer housing  12 ′ from that of the magnetic coupling force between the external magnet  28  on the bottom of the outer housing  12 ′ and the internal magnet, the cover  14 ′ is supported by suspension springs  162 . Changes in the force exerted on suspension springs  162  are read by a pressure transducer  160 . As shown in  FIG. 16 , the cover  14 ′ fits in a cut-out portion on the top edge of outer housing  12 ′ and rests on suspension springs  162 . The cover  14 ′ compresses springs  162  which are electrically connected to the pressure transducer  160 . The load signal from the suspension springs  162  is analyzed so that the amount of load induced by the clinician is subtracted out from the load induced by the magnetic coupling force. 
     The embodiments of the devices described herein may be introduced inside a patient using minimally invasive or open surgical techniques. In some instances it may be advantageous to introduce the devices inside the patient using a combination of minimally invasive and open surgical techniques. Minimally invasive techniques may provide more accurate and effective access to the treatment region for diagnostic and treatment procedures. To reach internal treatment regions within the patient, the devices described herein may be inserted through natural openings of the body such as the mouth, nose, anus, and/or vagina, for example. Minimally invasive procedures performed by the introduction of various medical devices into the patient through a natural opening of the patient are known in the art as NOTES™ procedures. Some portions of the devices may be introduced to the tissue treatment region percutaneously or through small—keyhole—incisions. 
     Endoscopic minimally invasive surgical and diagnostic medical procedures are used to evaluate and treat internal organs by inserting a small tube into the body. The endoscope may have a rigid or a flexible tube. A flexible endoscope may be introduced either through a natural body opening (e.g., mouth, nose, anus, and/or vagina) or via a trocar through a relatively small—keyhole—incision incisions (usually 0.5-2.5 cm). The endoscope can be used to observe surface conditions of internal organs, including abnormal or diseased tissue such as lesions and other surface conditions and capture images for visual inspection and photography. The endoscope may be adapted and configured with working channels for introducing medical instruments to the treatment region for taking biopsies, retrieving foreign objects, and/or performing surgical procedures. 
     All materials used that are in contact with a patient are preferably made of biocompatible materials. 
     Preferably, the various embodiments of the devices described herein will be processed before surgery. First, a new or used instrument is obtained and if necessary cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK® bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility. Other sterilization techniques can be done by any number of ways known to those skilled in the art including beta or gamma radiation, ethylene oxide, and/or steam. 
     Although the various embodiments of the devices have been described herein in connection with certain disclosed embodiments, many modifications and variations to those embodiments may be implemented. For example, different types of end effectors may be employed. Also, where materials are disclosed for certain components, other materials may be used. The foregoing description and following claims are intended to cover all such modification and variations. 
     Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.