Abstract:
A mobile patient stretcher is provided and particularly adapted for additional use as a pain clinic treatment table designed to accommodate a C-arm of a fluoroscopic or like imaging apparatus. The stretcher litter top or patient support surface is radiolucent and includes selectively removable lateral side rail sections so that the litter top can be selectively converted into an hourglass shape without side rails as required for treatment procedures and/or C-arm access and imaging. On the other hand, with the lateral side rail sections in place, the stretcher includes a full-width patient support surface, and also includes a radiolucent fowler back rest, selectively deployable side rails, and a hydraulically or otherwise controlled conventional wheeled stretcher base that is adapted to place the patient support surface in a raised, lowered, Trendelenburg, or reverse Trendelenburg orientation. Thus, the stretcher can be used as a fully functional stretcher to transport a patient to and from a procedure area and a recovery area, provides a comfortable resting place with a fowler back rest for a patient, and is also usable as a treatment table during fluoroscopic or other imaging procedures.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a mobile patient stretcher or trolley. More particularly, the invention relates to a full-width, fully functional patient stretcher that is particularly adapted for additional use as a pain clinic treatment table designed to accommodate a C-arm of a fluoroscopic or like imaging apparatus. The stretcher litter top or patient support surface is radiolucent and includes selectively removable lateral side rail sections so that the stretcher support surface can be selectively converted into an hourglass shape without side rails as required for treatment procedures and/or C-arm access and imaging. On the other hand, with the lateral side rail sections in place, the stretcher includes a full-width patient support surface, and also includes a radiolucent fowler back rest, selectively deployable side rails, and a hydraulically or otherwise controlled conventional wheeled stretcher base that is adapted to place the patient support surface in a raised, lowered, Trendelenburg, or reverse Trendelenburg orientation. Thus, the present invention can be used as a fully functional stretcher to transport a patient to and from a procedure area and a recovery area, provides a comfortable resting place with a fowler back rest for a patient, and is also usable as a treatment table during fluoroscopic or other imaging procedures. 
     Prior stretchers have been designed for C-arm access. However, none have provided the utility and safety of a fully functional, dual-pedestal stretcher in combination with a procedure table that is adapted to accommodate a C-arm. For example, some prior designs have omitted side rails altogether, and others do not allow the side rails to be raised and lowered as needed for patient safety and access. Other prior designs have not included a fowler backrest for patient comfort. To ensure C-arm access, other prior designs have reduced the width of the patient support surface over its entire length, but this approach reduces the comfort of the patient and obviously increases the risk that a patient can fall from the support surface. 
     In light of the foregoing, a need has been identified for a full size and fully functional stretcher that easily and conveniently converts into an hourglass shaped treatment table that accommodates a C-arm. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a new and improved stretcher adapted for C-arm access is provided. 
     In accordance with a first aspect of the present invention, the stretcher includes a litter top defined by a foot section of a first width, a head section of a second width, and a central section interconnecting said foot and head sections. The central section has a third width less than the first and second widths of the foot and head sections. Thus, the litter top defines an hourglass shaped perimeter with first and second recessed areas located on opposite lateral sides. A wheeled base supports the combined stretcher and treatment table above a support surface and includes a chassis and first and second spaced-apart and selectively extensible pedestal supports projecting upwardly from the chassis. The first and second pedestal supports are operably connected to the litter top and support same above the base. A first side rail assembly is adapted for selective connection to the litter top. The first side rail assembly includes: (i) a first gap filler panel member that is received in and substantially fills the first recessed area when the first side rail assembly is connected to the litter top; and, (ii) a first side rail that is selectively movable between an extended position projecting upwardly substantially above the litter top and a lowered position. A second side rail assembly is also provided and adapted for selective connection to the litter top. The second side rail assembly includes: (i) a second gap filler panel member that is received in and substantially fills the second recessed area when the second side rail assembly is connected to the litter top; and, (ii) a second side rail that is selectively movable between an extended position projecting upwardly substantially above the litter top and a lowered position. 
     One advantage of the present invention is the provision of a new and improved stretcher adapted for C-arm access. 
     Another advantage of the present invention resides in the provision of a fully functional stretcher that can be configured to accommodate a C-arm of a fluoroscopic imaging device during oblique and lateral imaging of a patient&#39;s spine. 
     A further advantage of the present invention is found in the provision of a stretcher adapted for C-arm access wherein the side rails are selective movable between raised and lowered positions, and wherein the side rails are selectively removable from the stretcher so that the patient support surface is thereby converted from a rectangular shape into an hourglass shape with the recessed portion of the hourglass shape: (i) defining at least 45%-55% of the overall length of the patient support surface; (ii) located at least substantially between the pedestals of the support base; and, (iii) positioned to correspond with the location of a patient&#39;s spine (i.e., extending at least between a patient&#39;s cervical spine region and lumbar spine region) when the patient is placed on the patient support surface in the proper orientation with his/her head located at the head-end of the stretcher. 
     Still another advantage of the present invention is found in the provision of a stretcher adapted for C-arm access that also includes a fowler backrest for patient comfort. 
     Yet another advantage of the present invention resides in the provision of a stretcher adapted for C-arm access that includes a dual-pedestal base (preferably hydraulic) for lowering the patient support surface for patient ingress/egress, raising the patient support surface for C-arm access and medical procedures, and placing the patient support surface in Trendelenburg or reverse Trendelenburg orientation. 
     A further advantage of the present invention resides in the provision of a stretcher adapted for C-arm access wherein the stretcher base has four wheel locking brakes and steering. 
     Still other benefits and advantages of the invention will become apparent to those of ordinary skill in the art upon reading and understanding the following specification. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention takes form from certain components and arrangements of components, preferred embodiments of which are illustrated in the accompanying drawings that form a part hereof and wherein: 
     FIG. 1 is a side elevational view of a stretcher adapted for C-arm access formed in accordance with the present invention; 
     FIG. 2 is a top plan view of the stretcher shown in FIG. 1, with one of its removable side rail assembly sections attached to the stretcher and the other detached from the stretcher and illustrated in phantom lines; 
     FIG. 3 is a head end elevational view of the stretcher shown in FIG. 1 illustrating pivoting movement of one of the side rails between a raised position (shown in solid lines) and a retracted or lowered position (shown in phantom lines); 
     FIG. 4 is an exploded isometric view of a preferred removable rail section latch assembly; and, 
     FIG. 5 is an exploded isometric view of a preferred removable side rail assembly formed in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings, wherein the showings are for purposes of illustrating preferred embodiments of the invention only and not for purposes of limiting same, FIGS. 1-3 illustrate a treatment stretcher adapted for C-arm access formed in accordance with the present invention. The subject stretcher is defined by five main sub-assemblies or sections: (i) base A; (ii) litter top B supported by the base; (iii) fowler backrest C pivotably connected to the litter top; (iv) a first (left) side rail assembly D adapted for releasable connection to a first (left) side of the litter top; and, (v) a second (right) side rail assembly E adapted for releasable connection to a second (right) side of the litter top. 
     Turning first to the base A, it is conventional in all respects and preferably comprises at least four caster wheels  10  secured to the corners of a chassis  12 . The base A preferably also comprises a conventional braking/steering system including pedals  20  located adjacent each wheel. As is well known in the art, each pedal  20  is operably connected to each wheel  10  of the stretcher and can be placed in either one of three operative position—(i) a neutral position wherein each wheel is free to roll and pivot about a vertical axis; (ii) a steer position wherein each wheel is free to roll and one wheel is fixed parallel to the longitudinal axis of the base to facilitate steering of the stretcher; and, (iii) a brake position wherein at least one and preferably all of the wheels are restrained against rotation. Of course, the base A can optionally include a fifth-wheel steering system as is well known in the art, and those of ordinary skill in the art will recognize that any other suitable wheel arrangement and control system can be used without departing from the overall scope and intent of the present invention. 
     The base A further comprises first and second pedestals  30 , 32  projecting upwardly therefrom. These pedestals preferably each comprise a selectively extensible/retractable fluid cylinder such as the preferred a hydraulic cylinders  36   a , 36   b , respectively. The cylinders  36   a , 36   b  can be encased in a flexible rubber or similar housing  38  for protection, aesthetics, and/or safety if desired as illustrated in connection with the cylinder  36   a . An outer or distal end  40   a , 40   b  of the cylinders  36   a , 36   b , respectively, is fixedly secured to the litter top B to support same above the base A. The base A further comprises a plurality of foot pedals  42  or other suitable convenient means by which an operator is able to control the flow of fluid into and out of one or both of the cylinders  36   a , 36   b  in a conventional manner. This, then, allows the litter top to be placed in a lowered, horizontal state (for patient ingress/egress), a raised horizontal state (for patient procedures), the Trendelenburg position, or the reverse Trendelenburg position. Here, again, those of ordinary skill in the art will recognize that the base can alternatively utilize electric motors, mechanical systems, or any other means for supporting and controlling the orientation of the litter top B. 
     With particular reference to FIG. 1, it should be noted that a first or foot end  52  of the litter top extends a substantial distance beyond the foot end  44  of the base A. Thus, the stretcher preferably incorporates an anti-lift system, such as a high-pressure gas cylinder  46  and associated cable restraint  48  connected to the second or head end  54  of the litter top B to prevent accidental movement of the head end  54  of the litter top upwardly away from the base A when excessive weight is placed on the foot end  52  of the litter top. This preferred anti-lift system is disclosed in full detail in commonly owned U.S. Pat. No. 5,402,543, the disclosure of which is hereby expressly incorporated by reference herein. 
     The litter top B is defined to have an hourglass shape as is readily apparent in FIG.  2 . Specifically, the foot and head ends  52 , 54  of the litter top are of similar width W 1 , preferably approximately twenty-eight to thirty inches, and are interconnected by a central, recessed section  56  that has a constant width W 2  that is less than the width of the foot and heads ends  52 , 54 . Preferably, the central litter top section has a width W 2  of approximately fifteen to eighteen inches. Of course, the width W 2  is reduced relative to the width W 1  so that a C-arm fluoroscope or similar imaging device can be accommodated by the central section  56  of the litter top B, i.e., the C-arm will be able to encompass the central section  56  and be adapted for rotational movement about the central section  56  without interference. 
     The litter top B is defined from a suitable radiolucent material. In one preferred embodiment, the litter top is defined from a carbon fiber composite material, although any other radiolucent material can be used. First and second end bumper rail assemblies  58 a, 58 b are preferably connected to the first and second ends  52 , 54  of the litter top B to protect same. The bumper rail assemblies  58   a , 58   b  include or define mounting wells/ports  60  that are adapted to receive and support I.V. rods, end boards, monitor shelves, push bars, and other conventional stretcher accessories. 
     The litter top B, itself, preferably has a length L (not including the bumper rails  58   a , 58   b ) sufficient to accommodate adult human patients. A preferred length is approximately seventy-five to eighty-five inches. With continuing reference to FIG. 2, it is preferred that the central section  56  of the litter top B defines forty-five to fifty-five percent (most preferably approximately fifty percent) of the overall length L of the litter top B. Furthermore, it is most preferred that the foot section  52  of the litter top define at least thirty percent of the overall length L, and that the head section  54  define only ten to twenty percent of the overall length L. 
     From these dimensions and an examination of FIG. 2, those of ordinary skill in the art will recognize that a patient lying on the litter top with his/her head at the head end  54  will be positioned so that at least his/her entire spine will be disposed above the central, recessed portion  56  of the litter top B. Therefore, the patients entire spine region will be able to be imaged using a C-arm fluoroscope or similar C-arm imaging device. Furthermore, with reference to both FIGS. 1 and 2, it can be seen that the litter top is affixed to the cylinders  36   a , 36   b  or other pedestal structure so that the cylinders  36   a , 36   b  or other associated structure of the pedestals does not lie beneath the central section  56  of the litter top B. Thus, the pedestals  30 , 32  do not interfere with a C-arm of an associated imaging device without regard to the axial location of the C-arm along the length of the central top section  56 . 
     The subject stretcher further comprises a fowler backrest C hingedly connected to the litter top B for movement between a lowered position (as shown in solid lines in FIG. 1) and one or more raised positions (as shown in broken lines in FIG.  1 ). The fowler backrest C is provided primarily for patient comfort during transport or other times when procedures are not being performed on the patient. The fowler backrest C is, itself, also defined from a radiolucent material, preferably carbon fiber composite, and defines a width W 3  that is the same or slightly less than the width W 2  as illustrated in FIG.  2 . First and second hinges  60   a , 60   b  or another hinge structure is used to pivotably interconnect the fowler backrest C to the litter top B so that the fowler backrest is adapted for pivotal movement on an arc F between its raised and lowered positions. A handle  62  projects outwardly from the fowler backrest C and provides a suitable location by which an operator can grasp the fowler backrest and manually move it between its raised and lowered positions. In its lowered position, the fowler backrest is preferably spaced from the litter top B to eliminate pinch or shear points between the litter top and fowler backrest. The fowler backrest C preferably pivots relative to the litter top B at a point that will be comfortable to a patient supported on the litter top, i.e., just below the patient&#39;s pelvis. Both the exposed portion of the litter top B and fowler backrest C are preferably covered with a removal resilient mattress pad (not shown) for patient comfort and safety. 
     A fowler incline adjustment mechanism  70  is provided to releasably secure the fowler backrest in any desired one of its raised positions. Although pneumatic or fluid cylinders can be employed as the fowler incline adjustment mechanism as is generally well known in the art for conventional stretchers, it is most preferred that a manual, purely mechanical adjustment mechanism  70  be provided. With reference again to FIG. 1, the preferred incline adjustment mechanism comprises a strut  72  including a first end pivotably connected to the fowler backrest C and an opposite, second end. A track  74  is fixedly secured to the litter top B beneath the fowler backrest C and defines a plurality of different recesses or dwell points  76  that releasably receive and retain the second end of the strut  72 . Thus, an operator uses the handle  62  to raise the fowler backrest C and places the second end of the strut  72  into one of the dwell points  76  of the track  74 . The incline angle of the fowler backrest C is dependent upon which dwell point  76  holds the second end of the strut  72 . It is most preferred that the fowler backrest C be positionable at a plurality of different incline angles ranging between zero and forty degrees. Most preferably, as disclosed herein, the incline adjustment mechanism is located so that it is inoperable by a patient supported on the stretcher. 
     The stretcher further comprises first and second side rail assemblies D,E releasably connected to the litter top B. The side rail assemblies serve a dual purpose when connected to the litter top—they fill the gaps created by the reduced width of the central section  56  of the litter top relative to the foot and head ends  52 , 54  of the top, and they include side rails that can be raised to protect the patient and prevent the patient from falling off of the litter top. 
     With reference to FIG. 2, it can be seen that each side rail assembly D,E is adapted for selective connection to the litter top B to fill the recessed areas of the top resulting from the reduced width of the central section  56 . The stretcher includes first and second latch assemblies  80 , 82  connected to (preferably beneath) the litter top on opposite lateral sides thereof, and these latch assemblies are respectively adapted to releasably secure the first and second side rail assemblies D,E to the litter top B as is described in full detail below. With brief reference to FIG. 3, each side rail assembly D,E includes an elongated base rail  90  and a side rail  92 . The side rail  92  of each side rail assembly D,E is pivotably secured to its respective base rail  90  and adapted for pivoting movement along an arc G between a raised position as illustrated in solid lines and a lowered position as illustrated in phantom lines. 
     Referring now also to FIG. 5, the side rail assembly D is illustrated in further detail. The side rail assembly E is merely a mirror image. It can be seen that the side rail  92  is pivotably secured to the base rail  90  by pins  94   a , 94   b  or the like. First and second latches  96   a , 96   b  are pivotably connected to the side rail  92  and are adapted to engage respective mating portions  98   a , 98   b  of the base rail  90  when the side rail  92  is in its raised position. The first and second latches  96   a , 96   b  are spring biased into this latched condition. To release the latches  96   a , 96   b  for purposes of pivoting the side rail to its lowered position, an operator manually exerts pressure on a projecting lever portion  99   a , 99   b  of each latch so that the latches pivot against the force of their respective biasing springs  100   a , 100   b  and disengage from the mating portions  98   a , 98   b  of the side rail. 
     With continuing reference to FIG. 5, the side rail assembly D includes a plurality of mounting brackets  110  fixedly secured to the elongated base rail  90  at spaced intervals. To these mounting brackets a gap filler panel  112  defined from a suitable plastic, carbon fiber composite, or other material is fixedly secured by use of fasteners, adhesive, or the like. As may be seen in FIGS. 2 and 3, when the side rail assemblies D,E are connected to the litter top B, the gap filler insert panels  112  thereof respectively fill the recessed areas on opposite lateral sides of the litter top that are formed by the reduced width of the litter top central section  56  relative to the foot and head ends  52 , 54 . This prevents loose objects, extremities of the patient, and the like from passing between the side rails  92  and the litter top B. As with the litter top B and fowler backrest C, a resilient pad can be used to cover each gap filler panel  112  for safety and comfort. 
     With reference again also to FIG. 2, the elongated base rail  90  of each side rail assembly D,E projects outwardly beyond the opposite axial ends of the gap filler panel  112  so that first and second opposite ends  120 , 122  of the rail  90  are exposed. First and second brackets  130   a , 130   b  are affixed to the underside of the litter top B adjacent the intersection of the head section  54  and the central section  56  on opposite lateral sides. These brackets  130   a , 130   b  are adapted for respectively receiving and retaining the exposed first ends  120  of the side rail assemblies D,E as indicated by the arrow H 1 . The side rail assemblies D,E are simultaneously moved inwardly toward the litter top B as indicated by the arrow H 2 . First and second rail latch assemblies  80 , 82  are affixed to the underside of the litter top B adjacent the intersection of the foot section  52  and central section  56  of the top B on its opposite lateral sides. These latch assemblies  80 , 82  are adapted to receive and releasably retain the respective exposed rail ends  122  of the side rail assemblies D,E. In FIG. 2, the latch assembly  80  is closed and is retaining the rail end  122  of the assembly D in a fixed position relative to the litter top B. On the other hand, the latch assembly  82  is open and is adapted for placement of the rail end  122  of the assembly E therein. If desired, one or both of the rail ends  120 , 122  can include or define a foot adapted to support the rail  90  in an upright (vertical) position on a floor or other support surface when the assembly D,E is detached from the litter top B. 
     Turning now also to FIG. 4, the latch assembly  80  is illustrated (the latch assembly  82  is a mirror image). The assembly  80  includes a base plate  152  adapted for securement to the underside of the litter top B using fasteners or the like. A wall  154  projects upwardly from the base plate so that an open slot  156  is defined. This slot  156  is adapted to receive the exposed rail end  122  of the associated side rail assembly D. A cam member  160  is rotatably secured to the base plate  152  adjacent the slot  156 . The cam member  160  is adapted for rotation between an open position (see FIG. 2, latch member  82 ) wherein the cam member allows insertion/removal of the rail end  122  relative to the slot  156 , and a closed position (see FIG. 2, latch member  80 ) wherein the cam member engages a rail end  122  placed in the slot and prevents its removal. 
     Each latch assembly  80 , 82  includes a handle member  170  operably connected to the cam member  160  so that an operator is able to move the cam member between its opened and closed positions by simply pivoting the handle  170 . A preferred arrangement is illustrated in FIG.  4  and comprises a link member  180  connected to rotate with the cam member  160  and including a projecting shank  182  to which the handle  170  is secured. A stop block  190  projects outwardly from the base plate  152  and is positioned to engage a tab  172  projecting from the handle  170  so as to prevent pivoting movement of the handle  170  as required to rotate the cam member  160  to its opened position. However, the handle  170  is slidably secured to the shank  182  and is, thus, adapted for linear movement along the shank as indicated by the arrow J. A spring  176  secured by a screw  174  biases the handle into a first, retracted position where the tab  172  cannot move past the stop block  190 . However, an operator can axially extend the handle  170  by manual force so that the handle is able to pivot freely past the stop block  190  as indicated by the arrow K. A set-screw or pin  178  projects from the shank  182  of the link member  180  and is slidably received in a slot  184  defined in the handle  170 . The set-screw  178  thus secures the handle to the shank  182  and limits axial extension of the handle  170  away from the stop block  190 . A tensioner screw  192  is preferably threadably secured to the wall  154  and includes a distal end  194  adapted to engage the cam member  160  in a frictional fashion. A spring  196  is used to tension the screw  194  and hold same in a select position so that the tip  194  exerts a select force on the cam member  160  as desired and prevents free, uncontrolled movement thereof. 
     The invention has been described with reference to preferred embodiments. Of course, modifications and alterations will occur to others upon a reading and understanding the preceding specification. It is intended that the invention be construed as including all such modifications and alterations insofar as they are encompassed by the appended claims and equivalents thereof.