Abstract:
A device for quickly advancing/retracting a biopsy tool (or other driven object) into position through a colonoscope or other such scope. The device includes a drive actuator, a transmission for coupling the actuator to a driven object (biopsy tool), an attachment assembly that couples the device to the endoscope, such as to a biopsy port on the endoscope, an electronic control unit, and a user interface. Preferably, the driver/biopsy tool coupling consists of a motor and a combination of gears and friction rollers.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims priority from U.S. Provisional Ser. No. 62/005,555, filed May 30, 2014. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to systems and methods that facilitate the removal of multiple tissue samples and, more particularly, to a system for rapidly advancing and retracting biopsy forceps multiple times through an endoscope, e.g., a colonoscope, ureteroscope, or gastroscope. 
       BACKGROUND 
       [0003]    It is often desirable and frequently necessary to sample or test a portion of tissue, particularly in the diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other diseases or disorders. Biopsy may be done by open, minimally-invasive, or percutaneous techniques. Open biopsy, which is an invasive surgical procedure using a scalpel and involving direct vision of the target area, removes the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). Percutaneous biopsy, on the other hand, is usually done with a needle-like instrument through a relatively small incision, blindly or with the aid of an artificial imaging device, and may be either a fine needle aspiration (FNA) or a core biopsy. A minimally invasive procedure is performed by passing a sampling device through an endoscope or similar instrument such as a colonoscope or a ureteroscope. 
         [0004]    Referring now to  FIG. 1 , a colonoscopy is shown wherein a physician  12 , or endoscopist, performs a colonoscopy or other endoscopic procedure on a patient  14 . During the procedure, the patient  14  is anesthetized while lying on a bed, cart, or stretcher  16 . The patient  14  typically lies on his or her side, as shown. To perform a colonoscopy the physician  12  inserts a flexible tube  22  of a fiberoptic flexible colonoscope  24  through the rectum into the patient&#39;s colon. The flexible tube  22  usually contains a fiberoptic cable, an air line for inflating the colon, and a light for examining the mucosa therein. A communication cable  26  is coupled to medical equipment  28  supported by an equipment cart  30 . The medical equipment  28  includes signal processing equipment and other control devices for supplying the camera signal to a video monitor  32 . The cable  26  may also provide an avenue for passage of the air line for use in insufflation of the colon. 
         [0005]    Also with reference to  FIGS. 2-3 , the doctor examines the entire length of the rectum B and colon C with the colonoscope  24 . Special instruments such as elongated forceps  34  can be passed through a side port  36  in the colonoscope  24  to biopsy (sample) or remove any suspicious-looking areas such as polyps, if needed. For example,  FIG. 3  shows a distal end effector or grabber  38  of the forceps  34  projecting from within the flexible tube  22 . 
         [0006]    As seen in  FIGS. 4A and 4B , a distal end  40  of the colonoscope tube  22  includes a port  42  from which the distal grabber  38  of the forceps  34  emerges. A lens  44  provides the terminus of the fiberoptic cable, and a second open port  46  enables insufflation and expansion of the area. When the physician identifies a suspicious-looking area, such as the nodule N, he or she extends the distal grabber  38  and closes its jaws. The jaws are designed to resect and capture the nodule N, and the physician then can retract the grabber  38  proximally through the entire colonoscope tube  22 . 
         [0007]    Given that the colon is relatively long, the biopsy forceps  34  used in such procedures are thin flexible tubes (the length is typically between 2-3 m), as seen coiled in  FIG. 5 , which are advanced down and retracted back through the colonoscope tube  22 . There are a number of different styles, with cup or teeth jaws and with or without a guide needle between the jaws, for example. One current supplier, Conmed of Utica, N.Y., offers a complete line of disposable biopsy forceps called the Precisor® Biopsy Forceps. Usually the process involves taking multiple samples, sometimes as many as 30-40 biopsies. The process of advancing the forceps  34 , taking a sample, and then retracting the forceps is relatively time-consuming, and there is a need for a system that enables samples to be taken more quickly. 
       SUMMARY OF THE INVENTION 
       [0008]    The present application provides a device for quickly advancing/retracting a biopsy tool (or other driven object) into position through a colonoscope or other such scope. The device includes a drive actuator, a transmission for coupling the actuator to a driven object (biopsy tool), an attachment assembly that couples the device to the endoscope, such as to a biopsy port on the endoscope, an electronic control unit, and a user interface. Preferably, the driver/biopsy tool coupling consists of a combination of gears and friction rollers. 
         [0009]    In a preferred embodiment, the present application provides a system for performing an endoscopic procedure, comprising an endoscope, a tool displacement mechanism, and a flexible tool having an end effector for manually performing a surgical procedure. The endoscope has a proximal handle, a flexible tube that may be advanced through a patient&#39;s natural orifice until a distal end reaches a diagnostic target area, a working channel lumen from a port in the proximal handle through the flexible tube to a distal end thereof, and a scope having a lens on the distal end of the flexible tube. The tool displacement mechanism directly attaches to the port in the proximal handle of the endoscope and has a relatively small profile so as not to interfere with normal manual handling of the proximal handle. The tool displacement mechanism also includes a prime mover and a transmission. The flexible tool is sized to pass through a pathway in the tool displacement mechanism directly into the port in the proximal handle of the endoscope and into the working channel lumen. The transmission of the tool displacement mechanism converts motion generated by the prime mover to a displacement force in direct contact with the tool that drives the tool distally and proximally through the port and working channel lumen. 
         [0010]    A method of quickly obtaining biopsies is disclosed, including the steps of: attaching a drive assist unit to an endoscope, inserting a biopsy tool into the endoscope through the drive assist unit, activating the drive assist unit through a user interface and electronic control unit to advance the biopsy tool, manually steering the biopsy tool after it emerges from a distal end of the endoscope, manually obtain a biopsy sample, and activating the drive assist unit to retract the tool and remove the sample from the biopsy tool. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  illustrates a patient undergoing a colonoscopy performed by a physician using a colonoscope and a biopsy forceps; 
           [0012]      FIG. 2  is a perspective view of the colonoscope and biopsy forceps inserted into a side port; 
           [0013]      FIG. 3  is a schematic view of the colonoscope and biopsy forceps inserted therethrough within the patient&#39;s colon; 
           [0014]      FIGS. 4A and 4B  are perspective views of the distal end of the colonoscope showing a distal grabber of the forceps being used to resect a suspicious looking nodule; 
           [0015]      FIG. 5  shows a typical biopsy forceps in a coiled configuration; 
           [0016]      FIG. 6  is an elevational view of a colonoscope handle having an exemplary embodiment of a biopsy tool displacement mechanism coupled thereto; 
           [0017]      FIG. 7  is a partially cutaway view of the biopsy tool displacement mechanism; 
           [0018]      FIGS. 8A-8C  are sectional views taken along orthogonal planes through the biopsy tool displacement mechanism, and  FIG. 8D  is an enlargement of a wiper assembly at the top of the mechanism; and 
           [0019]      FIG. 9  is a flowchart depicting a preferred colonoscopy procedure using the biopsy tool displacement mechanism. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Colonoscopy typically involves insertion of a long, flexible and steerable colonoscope via the anus to access the large intestine. An integrated camera allows visualization, and a working channel permits the use of externally actuated biopsy forceps or similar devices. One of the difficulties of the procedure, and one which leads to more time spent under anesthesia, is the need to repeatedly insert and remove the biopsy tool through the working channel when tissue samples are taken. This is tedious and taxing for the doctor (taking about 15-20 seconds and 30-35 hand/arm strokes for each insertion) and poses a risk to the patient who remains under anesthesia for longer than is fundamentally necessary. Bowel puncture is also a potential risk as the biopsy tool emerges from the end of the colonoscope, and automated insertion of the tool would allow more controlled and repeatable insertion of the tool up to the tip of the colonoscope. Automation of this tool handling process would thus improve workflow and reduce patient risk. 
         [0021]    The present application provides an assistive device for endoscopic procedures, such as colonoscopies. The device is intended to be coupled to a conventional endoscope/colonoscope to provide more rapid advancement and retraction of a biopsy tool passed therethrough. In this respect, the biopsy tool displacement mechanism may be used to retrofit most endoscopes/colonoscopes on the market that have a working channel lumen for passage of biopsy tools. Typically such lumens terminate in a side port on a handle of the endoscope/colonoscope, but is conceivable that the lumen terminates along the axis of the handle, or in some other arrangements. Those of skill in the art will understand that the present application can be retrofitted to various such configurations. 
         [0022]      FIG. 6  illustrates a biopsy tool displacement mechanism  50  coupled to a side port  52  of a colonoscope handle  54 . A proximal end of a flexible tube  56  of the colonoscope is seen at the bottom, while a portion of a communication cable  58  is seen near the top. Again, the cable  58  may also provide an avenue for an air line for insufflation purposes. The functionality of the colonoscope will not be further described, and those of skill in the art will understand that various options exist, including the standard procedure described above in the background section. One exemplary colonoscope that can be retrofit with the biopsy tool displacement mechanism  50  is the Olympus CF-100TL, manufactured by the Olympus Corporation of Tokyo, Japan, available via various third-party vendors. 
         [0023]    The biopsy tool displacement mechanism  50  comprises a generally rectilinear housing  60  having a small motor housing  62  projecting from one side. An electric cord  64  extending from the motor housing  62  provides electricity for operation of the motor, as well as communications for its actuation. For example, the cord  64  may extend to a power source via a foot switch (not shown) which is used to actuate the motor inside the housing  62  in both directions, as will be described. A control box is not shown, but may be located remotely (wherever the user wants) and desirably houses a power supply and microcontroller. A control panel or interactive display can also be located either on the control box or in a third location to provide user input to the system, telling it whether to advance, retract, or stop driving the biopsy forceps. 
         [0024]    It should be noted that an electric motor is a desirable prime mover for use in driving the biopsy tool back and forth linearly through the flexible tube  56  of the colonoscope, though other prime movers could be used. For instance, hydraulic or pneumatic motors could serve the same function, and linear actuators could also be used if properly coupled, e.g., through a gear rack. 
         [0025]    A small tubular member  70  extends upward from an upper side of the housing  62  and provides a port for introduction of a biopsy tool  72 . The biopsy tool  72  can be seen in phantom passing downward through a lower plug member  74 , into the side port  52  of the colonoscope handle  54 , and then through the flexible tube  56 . A central axis of the tubular member  70  at the top of the housing  62  coincides with a central axis of the lower plug member  74  so that the biopsy tool  72  extends straight through the biopsy tool displacement mechanism. 
         [0026]    As will be explained, the displacement mechanism  50  provides a convenient assistive device to rapidly move the biopsy tool  72  through the flexible tube  56 . The biopsy tool  72  has a distal end effector such as a tissue grabber as described above for sampling biopsies and the like. As shown, the tool displacement mechanism  50  directly attaches to the port  52  in the proximal handle  54  of the endoscope and has a relatively small profile so as not to interfere with normal manual handling of the proximal handle. That is, the mechanism  50  may weigh 1-2 lbs and extend out from the side of the handle  54  less than one half of the length of the handle, e.g., no more than 3-4 inches. 
         [0027]    The present application is particularly useful for rapidly advancing and retracting a biopsy tool  72  during a colonoscopy. However, the principles disclosed herein apply also to other tools that may be shuttled back and forth within an endoscope in general. For instance, procedures such as colonoscopic snare removal of polyps or placement of endoscopic stents are also encompassed. Indeed, the present assist device applies to all endoscopic procedures which use a flexible scope with a working channel, such as a gastroscope. In general, a scope is inserted in a natural orifice, and advanced to a diagnostic target area, whereupon a secondary tool is shuttled to and from the area to perform the assigned task. The flexible biopsy tool  72  is sized to pass through a pathway (described below) in the tool displacement mechanism  50  directly into the port  52  in the proximal handle and into the working channel lumen. As will be explained, a transmission of the tool displacement mechanism  50  converts motion generated by the prime mover to a displacement force in direct contact with the tool that drives the tool distally and proximally through the port and working channel lumen. 
         [0028]    The term, “distal end effector” will be used to encompass a tissue grabber such as shown in  FIGS. 4A and 4B , as well as other tools used with a larger endoscope, such as endoscopically placed stents. Consequently, “distal end effector” is broader than a tissue sampling head, and can also refer to these other tools. 
         [0029]    Now with reference to  FIG. 7 , a partially cutaway view of the biopsy tool displacement mechanism  50  illustrates exemplary transmission and drive components therein. The motor within the housing  62  rotates a drive shaft  80  which passes through a first chamber  82  and into a second chamber  84 . Within the first chamber  82 , a drive gear  86  fixed to rotate with the drive shaft  80  engages a driven gear  88  keyed to rotate with a driven shaft  90 . The driven shaft  90  extends parallel to the drive shaft  80 , and also extends across the first and second chambers  82 ,  84 . Rotation of the drive shaft  80  rotates the driven shaft  90  at the same speed but in the opposite direction via engagement of the gears  86 ,  80 . 
         [0030]    A pair of drive wheels  92   a ,  92   b  located within the second chamber  84  are mounted to rotate on the drive shaft  80  and driven shaft  90 , respectively. The drive wheels  92   a ,  92   b  are preferably made of a frictional material, such as an elastomer like silicone rubber. The drive wheels  92   a ,  92   b  come into close proximity so as to frictionally engage the biopsy tool  72  therebetween, thus displacing it in a proximal or distal direction through the flexible tube  56  of the colonoscope. Actuation of the motor, therefore, displaces the biopsy tool  72  in a distal or proximal direction, depending on the direction of rotation of the motor. 
         [0031]      FIGS. 8A-8C  are sectional views taken along orthogonal planes through an exemplary biopsy tool displacement mechanism  50 .  FIG. 8A  is a horizontal section looking down, much like the cutaway view of  FIG. 7 , and shows the motor housing  62  extending from one side of the device housing  60 . As explained, the drive shaft  80  extends from the motor housing  62  and across the first and second chambers  82 ,  84 . Although the figures are somewhat schematic, it will be understood that the drive shaft  80  mounts for rotation in bearings or other such journals supported by the device housing  60 . Likewise, the parallel driven shaft  90  is journalled for rotation across the first and second chambers  82 ,  84 . 
         [0032]    In one especially useful configuration, the device housing  60  may be segregated into two separate parts defining the first and second chambers  82 ,  84 . As illustrated in  FIG. 8A , the first chamber  82  is defined by an enclosed housing  94  within which a pair of shaft stubs  96   a ,  96   b  rotate. The first and second shaft stubs  96   a ,  96   b  project slightly through the wall of the housing  94  and into the second chamber  84 . The second chamber  84  is defined by an open housing  98  which couples to the enclosed housing  94  via clips or similar expedients (not shown). A pair of shaft stubs  100   a ,  100   b  are mounted to rotate within the open housing  98  of the second chamber  84 . More particularly, one end of each shaft stub  100   a ,  100   b  is supported for rotation by the housing  98 , while the second end is coupled to one of the ends of the shaft stubs  96   a ,  96   b  that project into the second chamber  84 . In the illustrated embodiment, annular couplers  102  are used between the respective shaft stubs  96 ,  100 . The annular couplers  102  provide a tight interference fit between the facing ends of the shaft stubs, and suffice as torque transmitters as the level of force needed to shuttle the biopsy tool  72  is relatively small. Of course, other coupling arrangements are possible, such as sleeves locked to the shaft stubs with set screws. Simple interference fit couplers  102  are desirable for the ease of assembly and disassembly. 
         [0033]    Providing two separable chamber housings  94 ,  98  enables the first chamber  82  having the motor attached thereto to be kept isolated from the biopsy tool  72 , and thus free from contamination. At the end of the procedure, the open housing  98  with drive wheels  92  can be unclipped from the closed housing  94  and discarded. The closed housing  94  housing having the motor can be easily sterilized and reused, thus avoiding the expense of replacing the motor and drive transmission. The closed housing  94  defining the first chamber  82  is thus a reusable part of the biopsy tool displacement mechanism, while the second chamber  84  defining the open housing  98  is a disposable part. Moreover, the ability to switch out the housing having the drive wheels  92   a ,  92   b  enables the device to be adapted to different sizes of biopsy tool  72 . For example, thicker biopsy tools  72  may require smaller drive wheels  92   a ,  92   b , and vice versa. 
         [0034]    With reference now to  FIGS. 8B and 8C , an exemplary lower plug member  74  is shown. The plug member  74  is desirably made of elastomeric material, such as silicone rubber, and includes a tapered and ribbed lower end  110  that enables a tight fit within the side port  52  of the colonoscope handle  54 .  FIG. 6  illustrates a cap member  112  attached via a lanyard  114  to the side port  52 . The cap member  112  fits within the side port  52  to keep out dirt and the like during periods of non-use. In this respect, the plug member  74  may be shaped like the cap member  112 , which is shown as a straight cylinder, or may be tapered as seen in  FIGS. 8B and 8C  for a firmer attachment. The plug member  74  includes an upper flange  116  that can be forced through a lower aperture  118  in the device housing  60  such that a reduced diameter neck region  120  fits directly within the aperture. Of course, other arrangements are possible included a threaded plug. Additionally, a Velcro strap  122  as seen in  FIG. 6  may be attached to the device housing  60  to further secure the biopsy tool displacement mechanism  50  to the colonoscope handle  54 . The strap  122  is simply wrapped around the handle  54  and its free ends connected. 
         [0035]    The enlargement of  FIG. 8D  illustrates an exemplary configuration for avoiding contamination of the colon during the procedure. Namely, an elastomeric wiper  130  in the shape of an annular washer is held firmly between an outer cap  132  and an inner ferrule  134 . The ferrule  134  in turn fastens into an upper aperture  136  in the device housing  60 . The ferrule  134  is shown threaded into the aperture  136 , but of course a similar arrangement as described above with respect to the plug member  74  can be utilized. A through hole in the elastomeric wiper  130  is sized slightly smaller than the outer diameter of the biopsy tool  72  so as to prevent foreign matter from passing downward into the second chamber  84 . This seal arrangement is believed to provide adequate sterility for the procedure while at the same time not impeding movement of the biopsy tool  72  to a great degree. In a preferred embodiment, the annular wiper  130  is made of the lubricious material such as silicone rubber or PTFE. Of course, more elaborate seals can be utilized if contamination is a greater worry. 
         [0036]    Use of the disclosed biopsy tool displacement mechanism  50  will now be described with respect to the flowchart seen in  FIG. 9 . Again, the preferred method is described with respect to a colonoscopy procedure, but it will be understood by those of skill in the art that similar steps can be implemented for other endoscopic procedures. Essentially, the displacement mechanism  50  enables a physician or medical technician to rapidly shuttle an elongated tool down and back up a larger endoscope tube. In the context of a colonoscopy, the tool may be a biopsy forceps for taking tissue samples, though other tools for other applications may also benefit from being rapidly shuttled back and forth in this manner. 
         [0037]      FIG. 9  discloses an initial step of advancing a flexible tube of a colonoscope through a patient&#39;s rectum into the patient&#39;s colon, and then observing an area within the colon using a scope having a lens on the distal end of the flexible tube. If the doctor observes an area of interest, such as a suspected polyp or tumor, he or she manually inserts an elongated biopsy forceps into a proximal handle of the colonoscope and into a lumen of the flexible tube. In order to shuttle the biopsy forceps rapidly through the flexible tube, the physician then activates a motor to displace the biopsy forceps in the distal direction at a first speed. The motor may form a part of the biopsy placement mechanism  50 , as described above. As also mentioned above, the length of the biopsy forceps may be up to 3 m, and advancing the biopsy forceps using a motor greatly speeds up the process. 
         [0038]    When the distal end effector of the biopsy forceps reaches the distal end of the flexible tube, advancement thereof is halted. This can be calibrated into the control system for the motor, such that displacement of the biopsy forceps automatically stops after a predetermined length, such as the length of the flexible tube of the colonoscope. For example, a microcontroller may be programmed to command the stepper motor for automatic advancement of the biopsy tool from insertion to near the tip of the colonoscope, with a manually driven “jog” mode thereafter for safe advancement into contact with tissue (alternatively, the tool can be advanced manually at this point by de-energizing the motor coils, and many practitioners may prefer this option). Alternatively, the physician may control advancement of the biopsy forceps through a foot pedal, or the like, and halt advancement when he or she recognizes the biopsy forceps has reached the distal end of the flexible tube. In any event, it is important to avoid expelling the biopsy forceps rapidly from the distal end of the flexible tube. 
         [0039]    The advantage of the automatic mode comes into play more prominently during tool insertion, when the surgeon is pushing the flexible tool and it is more likely to buckle, slowing down the insertion process. Full tool advancement to the tip of the colonoscope can be achieved in approximately 3 seconds (as compared with up to 30 seconds) without risk of tissue perforation, which is a concern when advancing the biopsy instrument manually (the operator may accidentally advance the tool too far and emerge forcefully at the end of the colonoscope). The advantage of not having to slow down tool advancement at this point is not only in time savings, but also in allowing the surgeon to focus his/her mental effort on performing the diagnostic procedure rather than avoiding errors. 
         [0040]    At this stage, the physician again manually manipulates the biopsy forceps to take a biopsy sample from within the colon. In this respect, the drive wheels  92   a ,  92   b  described above may be disengaged from contact with the biopsy forceps  72 . Alternatively, the frictional forces applied to the biopsy forceps  72  by the wheels  92   a ,  92   b  may be relatively small and easy to overcome by manually pushing the forceps therethrough. In any event, the doctor has full manual control of the tissue sampling operation. 
         [0041]    Once the tissue sample has been taken, the doctor again activates the motor to retract the biopsy forceps through the flexible tube lumen. The distance that the biopsy forceps is retracted can be calibrated so that the motor stops just when the distal end effector thereof reaches the colonoscopy handle. Alternatively, the doctor can also monitor the length of the biopsy forceps that is within the colonoscope, such as by viewing index markings along the forceps. Ultimately, the doctor removes the biopsy forceps completely out of the scope to deliver the biopsy sample so it can be placed in formalin for histologic processing and microscopic examination. The biopsy forceps can then be reinserted for additional biopsies, if needed, as shown by the feedback loop. 
         [0042]    As explained above, a compact electromechanical device attached to a colonoscope handle speeds and facilitates biopsy tool handling in colonoscopy. As seen above, an exemplary embodiment comprises a stepper motor, friction rollers, and a structural housing. One of the friction rollers is driven directly by the motor while the other is driven with equal rotational speed in the opposite direction via a pair of gears. Alternatively, the motor could directly drive a single friction roller, with a low-friction sliding surface or passive roller opposite. This produces ideally slip-free rolling contact into which the biopsy tool can be introduced to generate linear travel of the tool with speed equal to the product of the motor speed and roller radius. The stepper motor provides a desirable combination of high driving torque to overcome friction as the tool is advanced and easy backdriving when the coils are not energized (for manual control of the biopsy tool after it is advanced beyond the tip of the colonoscope). Thus, the biopsy tool can be manually operated as usual without need for removal of the automatic advancement device. The housing provides bearing support for the shafts and encloses the gearing, and has an aperture to press-fit onto the rubber biopsy port typical to colonoscopes. 
         [0043]    Due to concerns related to sterilization and reuse, the device was designed in two parts: a disposable section through which the biopsy tool passes, and a reusable, sealed section for the motor and gears. Since it does not come into direct contact with the soiled biopsy tool, this reusable section should only require exterior wipe-down as opposed to thorough break-down and sterilization. The two sections have interlocking mating geometries (“box” joints, visible in  FIGS. 8A and 8B ) such that they are easily attached/detached, and splined shaft couplers on the reusable section mate with their counterparts on the disposable section to transmit rotational motion to the rollers. The present application provides a simple device for automation of handling biopsy tools during colonoscopy procedures. Due to the simplicity of the exemplary device, it is inexpensive to produce and could provide a cost benefit in terms of reduction in procedure time, as well as improving safety. Furthermore, by significantly reducing the time and effort required for tool insertion, the device would reduce fatigue and the risk of repetitive use injury to the colonoscopist&#39;s arm and wrist. The tissue-contacting part of the device is designed to be disposable in order to facilitate the sterilization processes between procedures. Testing has indicated repeatable and reliable functionality for preventing accidental forceful excursion of the biopsy instrument beyond the tip of the colonoscope during insertion. Further testing in the presence of lubricants typically used in colonoscopy may be indicated to determine if any adjustment to surface properties of the friction rollers is necessary. 
         [0044]    Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and procedures disclosed or claimed. Although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. With regard to any flowcharts if included, additional and fewer steps may be taken, and the steps as shown may be combined or further refined to achieve the methods described herein. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments.