Patent Publication Number: US-11660092-B2

Title: Adapter for securing loading units to handle assemblies of surgical stapling instruments

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and prior to U.S. Provisional Patent Application No. 63/084,750, filed on Sep. 29, 2020, the content of which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     This disclosure relates to powered surgical stapling instruments having a rotating drive assembly. More specifically, this disclosure relates to an adapter for connecting a staple loading unit to a powered handle assembly. 
     BACKGROUND 
     Surgical stapling devices having powered handle are known. Such devices typically include a replaceable loading unit that is releasably secured to a powered handle. An adapter assembly is used to connect the loading unit to the powered handle. The adapter assembly may be releasable from the powered handle, and thereby permit replacement, or may be integrally formed with the powered handle. 
     One or more drive assemblies extend from the powered handle and operably connect with the loading unit when the loading unit is secured to the adapter assembly. In some stapling devices, the drive assembly rotates a drive screw in the loading unit that advances a sled to cause closing of a jaw assembly of the loading unit and stapling of tissue between jaws of the jaw assembly. A high force is reached with the drive assembly at the end of the stapling stroke when the sled reaches the end of its travel, or in the event of a misfire when the sled jams or otherwise locks with the jaw assembly, which may damage the adapter assembly and/or the handle assembly. 
     It would be beneficial to have a mechanism that prevents damage to the adapter assembly and/or handle assembly when a high force is experienced within the drive assembly. 
     SUMMARY 
     Accordingly, an adapter for releasably connecting a loading unit to a handle assembly includes a proximal drive shaft, a distal drive shaft, and a shear pin connecting the proximal drive shaft to the distal drive shaft. The proximal drive shaft includes proximal and distal portions. The proximal portion of the proximal drive shaft is configured for releasable connection to the handle assembly. The distal drive shaft includes proximal and distal portions. The distal portion of the distal drive shaft is configured for releasable connection to the loading unit. The shear pin is configured to rotationally fix the proximal drive shaft to the distal drive shaft and is configured to fracture to permit rotation of the proximal drive shaft independent of rotation of the distal drive shaft when a predetermined torque is applied to the distal drive shaft. 
     In certain aspects of the disclosure, the proximal portion of the distal drive shaft includes an annular flange, and the distal portion of the proximal drive shaft is received within the annular flange. The annular flange of the distal drive shaft and the distal portion of the proximal drive shaft may each define an opening. The shear pin may be configured for receipt through the opening in the annular flange of the distal drive shaft and the opening in the distal portion of the proximal drive shaft. 
     In some aspects of the disclosure, the adapter includes a locking plate that releasably secures the adapter to the handle assembly and the loading unit. The adapter may also include a button member secured to the locking plate. Movement of the button member may cause corresponding movement of the locking plate. The button member may be movable from a distal position in which the adapter is secured to the handle assembly and the loading unit, to a proximal position in which the adapter is releasable from the handle assembly and the loading unit. 
     In other aspects of the disclosure, the adapter includes first and second housing sections that rotationally support the proximal and distal drive shafts. The adapter may include a sleeve. The first and second housing sections may be received within the sleeve. The adapter may also include a spacer positioned between the proximal drive shaft and the distal drive shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the disclosure are described herein with reference to the accompanying drawings, wherein: 
         FIG.  1    is a perspective view of a surgical stapling instrument including a handle assembly and a loading unit that is connected to the handle assembly by an adapter according to aspects of the disclosure; 
         FIG.  2    is an enlarged view of the indicated area of detail shown in  FIG.  1   ; 
         FIG.  3    is a perspective side view of the adapter shown in  FIG.  1   ; 
         FIG.  4    is a perspective view of the adapter shown in  FIG.  1   , with parts separated; 
         FIG.  5    is an enlarged view of the indicated area of detail shown in  FIG.  4   ; 
         FIG.  6    is a side, cross-sectional view of the adapter shown in  FIG.  3   , taken along section line  6 - 6  shown in  FIG.  2   , with a locking plate and a button member of the adapter in a locked position; 
         FIG.  7    is the cross-sectional view of the adapter shown in  FIG.  6   , with the locking plate and the button member of the adapter in an unlocked position; 
         FIG.  8    is a cross-sectional view of the adapter shown in  FIG.  3   , taken along section line  8 - 8  shown in  FIG.  6   , with a shear pin of the adapter intact; 
         FIG.  9    is side, cross-sectional view of an end effector of the loading unit of the surgical stapling instrument shown in  FIG.  1    taken along section line  9 - 9 , with a cartridge assembly of the end effector removed; and 
         FIG.  10    is the cross-sectional view of the adapter shown in  FIG.  8   , subsequent to shearing or fracturing of the shear pin. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the disclosed adapter for surgical instruments having at least one rotating drive assembly are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein the term “distal” refers to that portion of the adapter assembly or surgical device, or component thereof, farther from the clinician, while the term “proximal” refers to that portion of the adapter assembly or surgical device, or component thereof, closer to the clinician. As used herein the term “clinician” refers to a user, a surgeon, an assistant, or any other medical personnel involved with a surgery. 
       FIG.  1    illustrates a surgical stapling instrument  5  including an adapter in accordance with aspects of the disclosure, shown generally as adapter  100 , releasably connecting a loading unit  50  with an adapter assembly  20  of a powered handle assembly  10 . 
     The surgical stapling instrument  5  will only be described to the extent necessary to fully disclose the aspects of the disclosure. For a detailed description of the structure and function of exemplary powered handle assemblies, please refer to U.S. Pat. Nos. 9,055,943 and 9,023,014. For a detailed description of the structure and function of exemplary adapter assemblies and loading units, please refer to U.S. Pat. No. 10,117,650. 
     The powered handle assembly  10  includes a handle  12  and the adapter assembly  20 . The handle  12  is configured for operable engagement by a user and includes a battery (not shown) and a motor (not shown) for rotating a drive shaft  22  ( FIG.  6   ) extending through the adapter assembly  20 . Although shown and described including only a single drive shaft, it is envisioned that the powered handle assembly  10  may include multiple drive members. The function of the drive shaft  22  as described includes effectuating clamping and stapling of tissue. However, it is envisioned that rotation of the drive shaft  22  may effectuate alternative functions, e.g., articulation of the end effector  50 . 
     The adapter assembly  20  may be integrally formed with the powered handle assembly  10  or may be configured for releasable connection with the powered handle assembly  10 . Although shown and described as used with a powered handle assembly  10 , it is envisioned that the aspects of the adapter  100  may be modified for use with a manually actuated handle assembly (not shown). 
     As shown, the loading unit  50  includes a linear stapling end effector  52 . In aspects of the disclosure, the loading unit  50  is a multiple use loading unit (“MULU”) in that it is configured to releasably receive a staple cartridge assembly, e.g., staple cartridge  64 . Although aspects of the adapter  100  are shown and described with reference to the loading unit  50 , it is envisioned that the adapter  100  may be modified for use with any surgical instrument that includes a drive assembly with a rotating shaft. 
       FIG.  2    illustrates the adapter  100  of the surgical stapling instrument  5  ( FIG.  1   ) securing the loading unit  50  to the adapter assembly  20  of the powered handle assembly  10 . As will be described in further detail below, when the adapter  100  is in a locked condition, a button member  140  of the adapter  100  is in a distal or locked position. 
       FIGS.  3  and  4    illustrate the adapter  100  separated from the loading unit  50  and the adapter assembly  20 . The adapter  100  includes upper and lower housing sections  110 ,  120 , a locking plate  130  slidably supported relative to the upper housing  110 , the button member  140  affixed to the locking plate  130 , and a drive transfer assembly  150  supported within and extending through the upper and lower housing sections  110 ,  120 . The upper and lower housing sections  110 ,  120  are secured together within an outer sleeve  102 , and are secured within the outer sleeve  102  by rivets or pins  104 . As will be described in further detail below, a spring  138  biases the locking plate  130  to a locked position ( FIG.  5   ). 
     Each of the upper and lower housing sections  110 ,  120  define a longitudinal channel  111 ,  121  that, when received within the outer sleeve  102 , form a longitudinal passage  103  for receipt of the drive transfer assembly  150 . The upper housing section  110  includes a first flange  112  and a second flange  114  and defines a cutout  113  between the first and second flanges  112 ,  114 . The first and second flanges  112 ,  114  support the locking plate  130  and a portion of the locking plate  130  is slidable received within the cutout  113 . As shown, the upper and lower housing sections  110 ,  120  are secured together and/or maintained in a longitudinal fixed relationship with one another by tongues  116  and grooves  117 , or in any other suitable manner. It is envisioned that the upper and lower housing sections  110 ,  120  need not be secured to one another, and may instead be maintained relative to each other through receipt within the outer sleeve  102 . 
     The locking plate  130  of the adapter  100  includes a planar body  132 . A proximal portion  132   a  of the planar body  132  includes a latch  134  for engaging a tab  24  ( FIG.  6   ) of the adapter assembly  20  ( FIG.  1   ) of the powered handle assembly  10 . A distal portion  132   b  of the planar body  132  is configured to be received within a slot  51  ( FIG.  5   ) of the loading unit  50 . The locking plate  130  releasably secures the loading unit  50  with the powered handle assembly  10 . 
     The locking plate  130  of the adapter  100  defines a first elongate opening  133  in the proximal portion  132   a  of the planar body  132 , a second elongate opening  135  in the distal portion  132   b  of the planar body  132 , and a pair of openings  137  disposed between the first and second elongate openings  133 ,  135 . The first and second elongate openings  133 ,  135  of the locking plate  130  receive the respective first and second flanges  112 ,  114  of the upper housing section  110  of the adapter  100 . The first and second openings  133 ,  135  are sized to permit longitudinal movement of the locking plate  130  relative to the upper housing section  110  when the first and second flanges  112 ,  114  are received within the respective first and second elongate openings  133 ,  135 . 
     The locking plate  130  of the adapter  100  includes a prong  136  extending into the first opening  133 . The prong  136  of the locking plate  130  supports the spring  138  that biases the locking plate  130  to its locked position. ( FIG.  5   ). 
     The button member  140  of the adapter  100  is configured for operable engagement by a clinician. The button member  140  may include a marking or markings identifying the purpose of the button member  140 . For example, and as shown, the button member  140  includes an unlock symbol  142 , indicating to a clinician that movement of the button member  140  will unlock the adapter  100 . 
     The button member  140  of the adapter  100  includes a pair of posts  144  that are received within the pair of openings  137  of the locking plate  130 . The pair of posts  144  may be secured to the locking plate  130  by friction fit, welding, riveting, adhesives, screws, or other mechanical fasteners. 
     The drive transfer assembly  150  of the adapter  100  includes a proximal drive shaft  160  and a distal drive shaft  170  releasably secured to the proximal drive shaft  160  by a shear pin  152 . More particularly, the proximal drive shaft  160  of the drive transfer assembly  150  includes an insertion portion  162  and an annular flange  164  disposed proximal of the insertion portion  162 . An opening  163  extends through the insertion portion  162 . The distal drive shaft  170  of the drive transfer assembly  150  includes an annular sleeve  172  defining a recess  171  ( FIG.  6   ) sized to receive the insertion portion  162  of the proximal drive shaft  160 , and an opening  173  extending transversely through the annular sleeve  172  for receiving the shear pin  152 . The opening  173  in the distal drive shaft  170  is aligned with the opening  163  in the proximal drive shaft  160  to permit receipt of the shear pin  152  within the openings  163 ,  173 . A spacer  156  is disposed about the insertion portion  162  of the proximal drive shaft  160  and is received between the annular flange  164  of the proximal drive shaft  160  and the annular sleeve  172  of the distal drive shaft  170 . 
     As shown, a proximal end of the proximal drive shaft  160  defines an opening  165  ( FIG.  6   ) that receives an extension  22   a  ( FIG.  6   ) of the drive shaft  22  that extends from the powered handle assembly  10  ( FIG.  1   ) of the surgical stapling instrument  5 . A distal end of the distal drive shaft  170  includes an extension for receipt within a recess  55  ( FIG.  6   ) of a drive shaft  54  in the loading unit  50  of the surgical stapling instrument  5 . It is envisioned that the proximal drive shaft  160  of the adapter  100  may be releasably connected to the drive shaft  22  of the powered handle assembly  10  and the distal drive shaft  170  of the adapter  100  may be releasably connected to the drive shaft  54  of the loading unit  50  in any suitable manner. 
       FIG.  5    illustrates the shear pin  152  of the drive transfer assembly  150 . The shear pin  152  includes a cylindrical body  152   a  having a central body portion  154   a , and first and second end portions  154   b ,  154   c . As will be described in further detail below, the first and second end portions  154   b ,  154   c  of the shear pin  152  are configured to shear off from the central body portion  154   a  of the shear pin  152  to prevent damage to the adapter assembly  20  ( FIG.  1   ) and/or the powered handle assembly  10  when a predetermined force is reached in the drive transfer assembly  150  ( FIG.  4   ). More particularly, the first and second end portions  154   b ,  154   c  of the shear pin  152  are configured to shear from the central body portion  154   a  of the shear pin  152  when the distal drive shaft  160  locks or is otherwise prevented from movement. This may occur when a drive sled  70  of the end effector  60  is completely driven through the jaw assembly, or when the end effector  60  misfires and the drive sled  70  locks up and is no longer able to advance. In either event, continued rotation of the distal drive shaft  170 , which could cause serious damage to the adapter assembly  20  and/or the powered handle assembly  10  without intervention, is prevented. 
     In one aspect of the disclosure, the shear pin  152  defines annular grooves  155   a ,  155   b  between the respective first and second end portions  154   b ,  154   c  of the shear pin  152  and the central body portion  154   a  of the shear pin  152 . The annular grooves  155   a ,  155   b  provide weakened locations along the cylindrical body  152   a  of the shear pin  152  to facilitate shearing of the first and second end portions  154   b ,  154   c  from the body portion  154   a . It is envisioned that the shear pin  152  may instead include through holes (not shown), scoring, or be otherwise configured to facilitate shearing of the first and second end portions  154   b ,  154   c  from the body portion  154   a . It is also envisioned that the shear pin  152  may include a single annular groove. 
       FIG.  6    illustrates the adapter  100  securing the loading unit  50  connected to the adapter assembly  20  of the powered handle assembly  10  ( FIG.  1   ). The button member  140  is in the locked position such that the loading unit  50  cannot be separated from the adapter  100  and the adapter assembly  20  cannot be separated from the adapter  100 . In the locked position, the button member  140  is in a distal most position and is maintained in the locked position by a bias of the spring  138 . In the locked position, the latch  134  on the proximal portion  132   a  of the locking plate  130  of the adapter  100  engages the tab  24  of the adapter assembly  20  and the distal portion  132   b  of the locking plate  130  is received within the slot  51  of the loading unit  50  to prevent separation of the adapter assembly  20  and loading unit  50  from the adapter  100 . 
       FIG.  7    illustrates the adapter  100  with the button member  140  in an unlocked position. In the unlocked position, the button member  140  is moved against the bias of the spring  138  to a proximal-most or unlocked position. In the unlocked position, the latch  134  on the proximal portion  132   a  of the locking plate  130  of the adapter  100  is spaced from the tab  24  of the adapter assembly  20  and the distal portion  132   b  of the locking plate  130  is withdrawn from the slot  51  in the loading unit  50 . When the button member  140  is in unlocked position, the loading unit  50  may be separated from the adapter  100  and the adapter  100  may be separated from the adapter assembly  20  and/or the powered handle assembly  10 . 
       FIG.  8    illustrates a cross-sectional view of the drive transfer assembly  150  taken through the shear pin  152  connecting the proximal and distal drive shafts  160 ,  170  together. During normal operation of the surgical stapling instrument  5  ( FIG.  1   ), rotation of the proximal drive shaft  160  causes rotation of the distal drive shaft  170 . 
       FIG.  9    illustrates the end effector  60  of the loading unit  50 . The end effector  60  includes an anvil assembly  62  and a cartridge assembly  64 . A drive screw  66  extends through and is rotationally supported by the cartridge assembly  64  ( FIG.  1   ). The drive screw  66  is operably connected to the distal drive shaft  170  ( FIG.  8   ) such that rotation of the distal drive shaft  170  causes rotation of the drive screw  66 . A clamping member  68  operably engages the drive screw  66  and is configured to longitudinally move along the drive screw  66  upon rotation of the drive screw  66 . The end effector  60  further includes a sled  70  that is engaged by the clamping member  68  as the clamping member  68  is advanced through the cartridge assembly  64  to cause the ejection of staples (not shown) from a staple cartridge  64   a  ( FIG.  1   ) of the cartridge assembly  64 . 
       FIG.  10    illustrates a cross-sectional view of the drive transfer assembly  150  taken through the shear pin  152  connecting the proximal and distal drive shafts  160 ,  170  to each other subsequent to shearing of the shear pin  152 . As described above, when the sled  70  of the end effector  60  of the loading unit  50  is prevented from further advancement, e.g., reaches the terminus of the drive stroke, or binds with the cartridge assembly  64  ( FIG.  1   ), the drive screw  66  is prevented from turning. Forcing the drive screw  66  to turn when it cannot be further turned may cause damage to the adapter assembly  20  ( FIG.  1   ) and/or the powered handle assembly  10 . To prevent damage to the adapter assembly  20  and/or the powered handle assembly  10 , the first and second end portions  154   b ,  154   c  of the shear pin  152  are sheared or fracture from the central body portion  154   a  of the shear pin  152  to permit continued rotation of the proximal drive shaft  160  independent of the distal drive shaft  170 . 
     Subsequent to shearing of the shear pin  152 , the adapter  100  of the surgical stapling instrument  5  ( FIG.  1   ) no longer operates to actuate the end effector  60  of the loading unit  50 . More particularly, shearing of the shear pin  152  separates the connection between the proximal and distal drive shafts  160 ,  170  that is not repairable without replacing the shear pin  152 . Prior to reusing the surgical stapling instrument  5  ( FIG.  1   ) the adapter  100  is replaced with a new adapter  100 . In this manner, it is envisioned that a new adapter  100  may be used with every new firing of the surgical stapling instrument  5 . 
     Any of the components described herein may be fabricated from either metals, plastics, resins, composites or the like taking into consideration strength, durability, wearability, weight, resistance to corrosion, ease of manufacturing, cost of manufacturing, and the like. 
     It will be understood that various modifications may be made to the aspects of the disclosed adapters. Therefore, the above description should not be construed as limiting, but merely as exemplifications of aspects of the disclosure. Those skilled in the art will envision other modifications within the scope and spirit of the disclosure.