Patent Publication Number: US-2023144183-A1

Title: Tip protector for a surgical instrument, assembly and method

Description:
FIELD OF THE INVENTION 
     It is an object of the present invention a tip protector. 
     In particular, the present invention relates to a tip protector for a surgical instrument. 
     The present invention also relates to an assembly of tip protector and surgical instrument. 
     Furthermore, the present invention relates to a method. 
     BACKGROUND 
     Robotic surgery apparatuses are generally known in the art and typically comprise a master console, a robotic central tower (or robotic cart) and a plurality robotic arms extending from the central tower, an example of which is disclosed in document U.S. Pat. No. 10,864,051 of the same Applicant. Each robotic arm typically comprises a tele-operated robotic motorized positioning system (or manipulator) for moving a slave surgical instrument distally attached thereto, in order to position said surgical instrument so that can reach an operatory volume of the patient anatomy. Documents WO-2019-220407, WO-2019-220408 and WO-2019-220409 in the name of the same Applicant disclose several embodiments of master-slave robotic surgery system having a mechanically unconstrained, mechanically ungrounded master input tool designed to be hand-held by the surgeon in a predefined volume in order to actuate the slave surgical instrument. 
     The slave surgical instrument typically comprises an elongated shaft having at the distal end an articulated or jointed tip designed for operating a patient and usually comprising a metallic distal pointed end and/or a sharp blade for piercing and/or cutting a patient&#39;s tissue. The motorized robotic positioning system is therefore designed to position the tip of at least one surgical instrument at or near an operatory volume of the patient anatomy. Known cable driven motorized positioning systems typically include a set of motorized capstans or pulleys able to wind and unwind the cable for actuating a degree of freedom of the surgical instrument, for example the grip degree of freedom of the instrument tip. 
     After having positioned the tip at or near an operatory volume of the patient anatomy, the motorized robotic positioning system typically freezes, and the articulated device provides the desired degrees of freedom of motion to the tip. Documents U.S. Pat. No. 10,582,975, WO-2017-064303, WO-2017-064306, WO-2018-189721 and WO-2018-189722 in the name of the same Applicant disclose several embodiments of slave surgical instruments for robotic surgery having a pitch-yaw-grip distal articulated tip. 
     Slave surgical instruments having a flexible robotic arm proximal to the instrument tip are also known in the field. 
     Several surgical procedures, such as sutures, the execution of blood vessel anastomosis comprising small diameter vessels and nerves, the reconstruction of anatomic parts after the occurrence of traumatic lesions, in re-vascularization of tissues, reattachment of limbs, transplantation and replantation procedures, may be carried out by virtue of known slave surgical instruments. 
     The articulated tip of known slave surgical instruments are delicate and fragile components, because of the high technological content, and the fragility normally increases as the size of the tip miniaturizes. 
     At least for the reasons set forth above, it is strongly felt the need of protecting the tip of a slave surgical instruments for robotic surgery. 
     Known solutions to protect the tip of a slave surgical instrument include caps or cages fitting onto the distal tip thereof. The action of protecting a pointed tip or a sharp-trimmed blade prevents direct collisions of the tip against a hard object within the operatory field, thereby preventing damages to the tip, and thus allows the use of a same surgical instrument for several surgeries, after proper sterilization. Moreover, the action of protecting a pointed tip or a sharp-trimmed blade reduces the risk of unwanted damages to healthy organs, for example that can occur due to poor control over a robotic manipulation of the slave surgical instrument while approaching the patient&#39;s anatomy. 
     In particular, robotic-aided laparoscopy requires the slave surgical instrument to penetrate beneath the body skin through a set of pre-positioned surgical access in form of hollow trocars across the patient&#39;s skin. It is therefore critical that the slave surgical instrument tip is protected by a cap before its insertion into the hollow trocar. Known solutions designed for protecting the tip of a laparoscopic surgical instrument are shown in document US-2017-0224191, which shows a “V”-shaped tip cap having a distal cap shield, two flexible arms extending backwards from the cap shield and carrying each a collar portion made of an half-pipe for receiving the tip of the laparoscopic surgical instrument, a latching closure at the opposite end of the arms. A plurality of through holes are provided for drainage of liquids from the tip cap. An abutment stop element impedes the tip of the laparoscopic instrument to protrude from the tip cap. 
     Other known examples of tip protectors for laparoscopic surgical instruments are disclosed by US-2019-0313889, and in particular this document shows an embodiment of tip cap having a clamp device for attaching to the tip, a blocking device for locking in a predefined configuration the parts of the clamp device, and a plurality of through holes for drainage. In one embodiments the clamp device is made of two parts hinged one another near the distal end of the tip cap. In addition, document US-2016-0213434 shows a further known example of tip protector. 
     In the field of microsurgery, robotic apparatuses allow a higher degree of miniaturization of the surgical instrument when compared to traditional microsurgery and allows at the same time to reduce the transmission of hand tremor to the slave surgical instrument of the robotic surgery system. Some applications of robotic-aided microsurgery desire the presence of the surgeon within the sterile operatory arena during the robotic-aided surgery so that during a single intervention, the same micro-surgeon switches from robotic-aided microsurgery to traditional (non-robotic) microsurgery and vice versa. Thereby, the slave surgical instrument of the robotic micro-surgical system may be not in use for the whole duration of the surgery, and in particular the use of the robotic surgical instrument may be suspended for a while during a same surgery and then restored. 
     An example of cap for protecting a needle that is retractable along the instrument shaft is disclosed from document EP-2567662. 
     It is felt the need of exposing the tip of the surgical instrument, without for this reason requiring moving the surgical instrument away from an operatory volume of a patient&#39;s anatomy and thus also requiring to reposition the surgical instrument within the operatory volume of such a patient&#39;s anatomy. 
     It is therefore strongly felt the need of protecting the tip of a surgical instrument while the surgical instrument is positioned at or near an operatory volume of a patient anatomy. 
     SOLUTION 
     It is a scope of the present invention to overcome to the drawbacks cited with reference to the prior art. 
     This and other scopes are achieved by means of a tip protector according to claim  1 , as well as an assembly according to claim  12 , as well as a method according to claim  18 . 
     According to an aspect of the devices, assemblies, and methods according to the invention, a tip protector is provided for a surgical instrument having a shaft and an articulated instrument tip at a distal portion of the shaft, wherein the tip protector comprises a tip housing for releasably receiving the instrument tip, a clamp system, suitable for gripping a portion of the surgical instrument to position the tip protector, a distal through opening at or near the distal end of the tip housing. 
     The distal through opening may have an opening size that is adjustable so that said distal through opening can be adjusted in such way to become a through opening for at least the instrument tip, thereby making the tip protector repositionable at various location along the shaft of the surgical instrument. 
     The locations along the shaft may comprise features for holding in place the tip protector. 
     The distal opening of the tip protector may be elastically adjustable. 
     The tip protector may comprise one or more abutment surfaces for constraining at least some of the degrees of freedom of the articulated instrument tip in a predefined configuration. For example, the predefined configuration is a straight configuration of the articulated instrument tip aligned to the shaft. 
     A method for constraining an articulated instrument tip may comprise the steps of positioning and/or repositioning a tip protector having a tip housing comprising at least one tip abutment surface on the articulated instrument tip so that at least one tip abutment surface of the tip protector abuts against the instrument tip from opposite sides of the articulated instrument tip, exerting a constraining action on the articulated instrument tip, blocking at least one degree of freedom of the articulated instrument tip. 
     Thanks to the proposed solutions, it is allowed to selectively expose the articulated tip of a surgical instrument when the surgical instrument is within an operatory volume near or within a patient&#39;s anatomy as well as to protect the same tip of the surgical instrument when the surgical instrument is within the same operatory volume. 
     Thanks to the repositionable tip protector, protection and exposure of the tip is made faster and do not require to reposition the surgical instrument within the operatory volume. 
     Thanks to the proposed solutions, it is allowed to transfer any mechanical load from the tip protector to the shaft, thereby protecting the instrument tip from any overloading actions. 
     Thanks to the proposed solution is possible to constraining at least some of the degrees of freedom of the instrument tip in a predefined configuration. 
    
    
     
       FIGURES 
       Further characteristics and advantages of the tip protector, the assembly, the system and the method will appear from the description reported below of preferred embodiments, which are given as examples and are not meant to be limiting, which makes reference to the attached figures, in which: 
         FIG.  1    is an axonometric view showing diagrammatically a robotic surgery system, according to an embodiment; 
         FIG.  1     bis  is an axonometric view showing diagrammatically an assembly of tip protector and surgical instrument, according to an embodiment; 
         FIGS.  2 ,  3  and  4    are elevation side view showing diagrammatically an assembly of tip protector and surgical instrument in different configurations, according to an embodiment, as well as some steps of a method according to a possible mode of operation, wherein  FIG.  2    shows a partial cross-section for sought of clarity; 
         FIG.  5    is a cross-section along the longitudinal direction showing a tip protector covering an instrument tip, according to an embodiment; 
         FIG.  6    is an axonometric view showing a tip protector, according to an embodiment; 
         FIG.  7    is an axonometric view showing a tip housing of a tip protector, according to an embodiment; 
         FIG.  8    is an elevation side view according to the point of view indicate by the arrow VIII of  FIG.  7   ; 
         FIGS.  9  and  10    are elevation side views showing diagrammatically a tip protector clamped against different portions of the shaft of a surgical instrument, according to an embodiment, as well as some steps of a method according to a possible mode of operation; 
         FIGS.  11  and  12    are cross-sectional views of a tip protector, according to an embodiment, fitted onto the shaft of a surgical instrument, as well as some steps of a method according to a possible mode of operation; 
         FIG.  13    is an axonometric view showing the clamping system of a tip protector, according to an embodiment; 
         FIG.  14    is an axonometric view of the tip protector of  FIG.  13    wherein only one of two pieces of the tip protector is shown; 
         FIG.  15    is an axonometric view, which diagrammatically shows an instrument tip of a surgical instrument, according to an embodiment; 
         FIG.  16  ( a )-( b )  shows diagrammatically an assembly of tip protector and surgical instrument in different configurations, according to an embodiment; 
         FIG.  17    is a diagrammatic cross-section along the longitudinal direction showing a tip protector covering an instrument tip, according to an embodiment; 
         FIG.  18    is a diagrammatic cross-section along the longitudinal direction showing a tip protector covering an instrument tip, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF SOME EMBODIMENTS 
     According to a general embodiment, it is provided a tip protector  601  for a surgical instrument  610 . The surgical instrument  610  has a shaft  611  extending along a longitudinal direction X-X and an articulated instrument tip  612  at a distal portion  613  of the shaft  611 . 
     The tip protector  601  comprises a tip housing  602  for releasably receiving the articulated instrument tip  612 , a clamp system  603 , suitable for gripping a portion of the shaft  611  to position the tip protector  601 , and a distal through opening  605  at or near the distal end  608  of the tip housing  602 . 
     Said distal through opening  605  has an opening size  606  that is adjustable so that said distal through opening  605  can be adjusted in such way to become a through opening for at least the instrument tip  612 , thereby making the tip protector  601  repositionable at various location along the shaft  611 . 
     Preferably, said tip housing  602  comprises at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ suitable for abut against the instrument tip  612  from opposite sides thereof for exerting a constraining action on the instrument tip  612  at least in a direction which is transversal to the longitudinal direction X-X of the shaft  611 , with the purpose to block at least one of the degrees of freedom of said articulated instrument tip  612 . 
     Thereby, when the articulated tip  612  is housed within the cavity of the tip housing  602 , said at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ abuts against the articulated tip  612  from opposite sides of the tip  612 , exerting a constraining action on the articulated tip  612 , said constraining action blocks at least one degree of freedom of the articulated tip  612 . 
     The articulated tip  612  may have also one or more translational degrees of freedom blocked by the tip protector  601  when the articulated tip  612  is received within said housing  602 . 
     According to a preferred embodiment, said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ is suitable to block each and all the degrees of freedom of said articulated instrument tip  612 . Thereby, when the articulated tip  612  is housed within the cavity of the tip housing  602 , said at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ abuts against the articulated tip  612  from opposite sides of the tip  612 , exerting a constraining action on the articulated tip  612 , said constraining action blocks each and all the degrees of freedom of the articulated tip  612 , for example the degrees of freedom of pitch P, yaw Y and grip G. 
     Preferably, said constraining action is suitable for blocking at least one of the degrees of freedom of said articulated instrument tip  612  even when said at least one of the degrees of freedom is actuated. When said constraining action blocks each and all the degrees of freedom of the articulated tip  612 , said constraining action blocks each and all the degrees of freedom even when said at least one of the degrees of freedom is actuated. 
     According to a preferred embodiment, the tip protector  601  comprises one or more further abutment surfaces  629 ′,  629 ″, also called shaft abutting surfaces  629 ′,  629 ″, suitable for abut against the instrument shaft  611  of the surgical instrument  610 , with the purpose of acting as a reference for exerting said constraining action on the articulated instrument tip  612 . 
     According to a preferred embodiment, said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ is connected to at least one elastic element so that said constraining action is an elastic constraining action, and preferably said elastic constraining action is an auto-centering [i.e.: self-centering] constraining action. 
     According to a preferred embodiment, the tip protector  601  comprises a locking mechanism  607  for temporary limiting the distal opening size  606  within a predefined size opening value, which prevents the instrument tip  612  from passing through the distal through opening  605  of the tip housing  602  with the purpose of strengthen said constraining action. 
     According to a preferred embodiment, said tip protector  601  is made of two pieces  601 ′ and  601 ″, each of said two pieces  601 ′ and  601 ″ being a rigid body comprising at least one elastically flexible part. 
     As mentioned above, said surgical instrument  610  comprises a shaft  611  and an articulated instrument tip  612  at or near a distal portion  613  of the shaft  611 , as diagrammatically shown in the example of  FIG.  1     bis . According to an embodiment, said articulated instrument tip is at the distal end of the shaft  611 . Preferably, said instrument tip  612  of the surgical instrument  610  is articulated in respect of the shaft  611  of the surgical instrument  610  and is designed to operate within a predefined operatory volume  625 . According to an embodiment, said shaft  611  of the surgical instrument  610  defines a longitudinal direction X-X, substantially coinciding with the axis of longitudinal development of the shaft  611 . Preferably, said shaft  611  also defines a radial direction R-R orthogonal to the longitudinal direction X-X and incident the longitudinal direction X-X, and a circumferential direction C-C orthogonal to both the longitudinal direction X-X and the radial direction 
     R-R. Preferably, the longitudinal, radial and/or and circumferential directions X-X, R-R, C-C are defined also on the tip protector  601  when considered alone. The longitudinal direction X-X coincides with the centerline x-x of the tip protector  601 . The tip protector  601  may have a substantially symmetric body in respect of the centerline x-x, although according to some embodiments it does not have a symmetric body. The symmetry of the tip protector  612  may be functional with respect to said centerline x-x and/or to said longitudinal direction X-X of the shaft  611 . 
     The shaft  611  may be a rigid straight shaft having a single axis of longitudinal development, or may be a rigid curved shaft, or may be a flexible shaft made of a chain of a plurality of shaft links having local axis of longitudinal development. 
     The surgical instrument  610  is preferably designed for performing robotic surgery, for example robotic-aided microsurgery and/or robotic-aided laparoscopic surgery, preferably as part of a master-slave robotic surgery system  620  comprising a master console  621  controlling the surgical instrument  610 , as shown for example in  FIG.  1   . 
     As mentioned above, said tip protector  601  comprises a tip housing  602  or first housing  602  for releasably receiving the articulated instrument tip  612 . The size, shape and material of the tip housing  602  may be chosen in order to receive the articulated instrument tip  612  of a specific surgical instrument  610 . 
     According to an embodiment, said tip housing  602  comprises at least one protective distal wall  608  suitable for at least partially contouring the articulated instrument tip  612  in order to protect the tip from impact with other objects and/or anatomic parts as well as to protect the patient&#39;s anatomy from unwanted interaction with the articulated instrument tip  612  of the surgical instrument  610 . 
     According to an embodiment, said tip housing  602  further comprises a proximal through opening  623 . Thereby, the body of the tip housing  602  defines a proximal through opening  623 , a distal through opening  605 , and a housing cavity  624  therebetween. 
     According to an embodiment, said tip housing  602  comprises at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ and preferably at least a pair of tip abutment surfaces  609 ′,  609 ″,  609 ′″ 609 ′″ suitable for abut against the instrument tip  612  from opposite sides of the instrument tip  612  in a direction which is transverse to the longitudinal direction X-X of the shaft  611 . 
     As mentioned above, said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ abuts against the articulated tip  612  from opposite sides of the articulated tip  612  in a direction which in transversal to the longitudinal direction X-X of the shaft  611 . According to a embodiment, said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ may abut against the articulated tip  612  in the longitudinal direction X-X. Thereby, the instrument tip  612  to abut thereagainst in the longitudinal direction X-X and also in the radial direction R-R. 
     Preferably, said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ is able to prevent that the articulated instrument tip  612  could be inclined of an unwanted inclination angle with respect of the shaft  611  when the tip protector  601  houses the tip  612 . 
     According to an embodiment, said protective distal wall  608  of the tip housing  602  comprises said at least one abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″; in other words, according to an embodiment, said at least one abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ belong to the protective distal wall  608 . 
     According to an embodiment, the tip protector  601  comprises at least a pair of tip abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″, preferably mutually opposite and facing said cavity of the housing  602 , said pair of tip abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ comprises an abutment surface and an abutment countersurface suitable for abut against the articulated instrument tip  612  from opposite sides thereof in the radial direction R-R, thereby preventing that the articulated instrument tip  612  could be inclined of an unwanted inclination angle with respect of the shaft  611  when the tip protector  601  houses the articulated tip  612 . A pair of abutment surfaces comprising an abutment surface and an abutment countersurface may be formed by two portions of a same surface of the housing  602  of the tip protector  601 . In the exemplary embodiment of the tip protector  601  shown in  FIGS.  17  and  18   , two pairs of tip abutment surfaces  609 ′, and  609 ″,  609 ′″ and  609 ″″ are shown, each pair comprising an abutment surface  609 ′,  609 ′″ and an abutment countersurface  609 ″,  609 ″″, and a pair of shaft abutment surfaces  629 ′,  629 ″ comprising a shaft abutment surfaces  629 ′ shaft abutment countersurface  629 ″ are also shown. Still referring to  FIGS.  17  and  18   , a pair of abutment surfaces  609 ′,  609 ″ abuts against a distal articulation of the articulated instrument tip  612  from opposite sides thereof, said distal articulation articulating the links  644 ,  645  and  646  about the yaw Y axis, thereby blocking the degrees of freedom of yaw and grip of the instrument tip  612 . Further, still referring to  FIGS.  17  and  18   , a pair of abutment surfaces  609 ′″,  609 ″″ abuts against an intermediate articulation of the instrument tip  612  from opposite sides thereof, said intermediate articulation articulating the links  643  and  644  about the pitch P axis, thereby blocking the degrees of freedom of pitch of the articulated instrument tip  612 . 
     The articulated instrument tip  612  is preferably thinner than the shaft  611 . In other words, the radial size of the articulated instrument tip  612  is preferably thinner than the radial size of the shaft  611 . 
     In the exemplary embodiment of the surgical instrument  610  shown in  FIG.  15   , the articulated tip  612  comprises pitch P, yaw Y and grip G degrees of freedom with respect to the shaft  611 . Thanks to the provision of said abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ of the tip housing  602  designed to abut against the articulated instrument tip  612  it is made possible to position/orient the articulated instrument tip  612  in a predetermined configuration while the tip protector  601  is fit onto the instrument tip  612  and the tip housing  602  receives the instrument tip  612  abutting thereagainst. Thereby, thanks to said tip protector  601  equipped with such abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ within said tip housing  602 , the degrees of freedom of the surgical instrument can be freezed in a predefined configuration. In other words, the tip protector  601  is able to temporary constrain the degrees of freedom of the surgical instrument tip  612 , for example at least some among pitch P, yaw Y and instrument grip G degree of freedom, and preferably at least the instrument grip G degree of freedom of the instrument tip  612 . According to an embodiment, the tip protector  601  having said abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ constrains all the degrees of freedom of pitch P, yaw Y, and grip G of the instrument tip  612 , when the tip protector  612  is fitted onto the instrument tip  612 . 
     According to an embodiment, the tip protector  601  is also able to temporary constrain the roll degree of freedom of the surgical instrument tip  612 . 
     Preferably, the tip protector  601  temporary constrains the articulated instrument tip  612  in a straight configuration, aligned along the longitudinal axis X-X of the instrument shaft  611 . Thereby, when the tip housing  602  of the tip protector  601  is positioned or repositioned onto the instrument tip  612 , the instrument tip  612  returns in said predefined straight configuration, as shown for example in  FIG.  16   . 
     The predefined configuration may be not straight, [i.e. a bent configuration] of the articulated instrument tip  612  forming for example a predefined bending angle with respect to the longitudinal direction X-X of the instrument shaft  611 . Where there is more than one rotational degree of freedom, said bent configuration imposed by the tip protector  601  may define an array of predefined bending angles with respect to the longitudinal direction X-X of the instrument shaft  611 . 
     The articulated instrument tip  612  may comprise a plurality of articulated links  643 ,  644 ,  645 ,  646  and driven by actuation cables or tendons  647 ,  647 ′,  648 ,  648 ′,  649 ,  649 ′. Preferably at least a portion of at least some of said tendons  647 ,  647 ′,  648 ,  648 ′,  649 ,  649 ′ slides onto the external surfaces of some of the links  634 ,  644 ,  645 ,  646 , said external surfaces preferably are ruled surfaces formed by straight lines all parallel one another and parallel to an axis of degree of freedom, e.g. pitch P and yaw Y of the articulated instrument tip  612 . Articulated instrument tip  612  comprises, according to an embodiment, pitch P, yaw Y and instrument grip G degrees of freedom. According to an embodiment, the surfaces onto which the tendons  647 ,  647 ′,  648 ,  648 ′,  649 ,  649 ′ slide are all made by wire electro-discharge machining, and preferably without requiring to individually reposition the links to be machined in a machining fixture. The machining fixture may be rotated to allow the machining of such surfaces. The articulated instrument tip  612  may comprise also a roll degree of freedom, in other words a rotational degree of freedom about the longitudinal direction X-X of the instrument shaft  611 . 
     Preferably, the tip protector  601  constrains in a predefined configuration the instrument tip  612  when the tip  612  is received into said tip housing  602  and said one or more abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ of the tip protector  601  abut against one or more portions [i.e. links  643 ,  644 ,  645 ,  646 ] of said articulated instrument tip  612 . To this end further one or more shaft abutment surfaces  629 ′,  629 ″ may be provided on the tip protector  601  to abut against the instrument shaft  611  of the surgical instrument  610 . 
     As mentioned above, said tip protector  601  preferably comprises a clamp system  603 , suitable for gripping/clamping a portion of the surgical instrument  610 . According to a preferred embodiment, said clamp system  603  is designed to grip/clamp a portion of the shaft  611  of the surgical instrument  610  to firmly position the repositionable tip protector  601 . Thereby, a grip/clamp action against the shaft  611  of the surgical instrument  610  is exerted by said clamp system  603 . 
     According to an embodiment, said claim system  603  comprises said further one or more shaft abutment surfaces  629 ′,  629 ″ of the tip protector  601 . In other words, according to an embodiment, said one or more shaft abutment surfaces  629 ′,  629 ″ belong to the clamp system  603  of the tip protector  601 . According to an embodiment, said one or more shaft abutment surfaces  629 ′,  629 ″ belong to the housing  602  of the tip protector  601 . 
     According to an embodiment, said clamp system  603  comprises at least one elastic portion, such as a clip and/or an elastic tongue  615 , biased towards the gripping of a portion of the surgical instrument  610 . Thereby, the grip action is an elastic grip action exerted by means of elastic return of an elastic element such as a clip and/or an elastic tongue  615 . Preferably, such a elastic grip action is directed substantially along the radial direction R-R. According to an embodiment, said elastic tongue  615  of the clamp system  603  comprises a base root and a free end, and at least one clamping abutment portion  616  at or near the free end of the elastic tongue  615 . The clamping abutment portion  616  may be an enlarged head of the elastic tongue  615 . A projection designed for projecting radially inwards, i.e. towards the shaft  611 , may be provided at the free end of the tongue  615  and may form the clamping abutment portion  616 . 
     According to a preferred embodiment, said clamp system  603  is designed to substantially surround the shaft  611 . To this end, the clamp system  603  comprises a sleeve  617  that may be made of two half pipes  617 ′ and  617 ″, the sleeve  617  of the clamp system  603  is a through sleeve  617  forming a through channel  618  along the longitudinal direction X-X. Said through channel  618  thereby has a first proximal channel mouth  622  and a second opposite distal channel mouth  622 ′ and the through channel  618  extending therebetween. Said clamping abutment portion  616  may preferably be part of the sleeve  617  defining said through channel  618 . Said sleeve  617  may be preferably rigid so that not to conform to bends of the shaft, if any  611 . Thereby, the proximal channel mouth  622  and the distal channel mouth  622 ′ results substantially aligned. 
     According to a preferred embodiment, said half pipes  617 ′ and  617 ″ each comprises at least one elastic tongue  615  having a free end and said at least one clamping abutment portion  616  projecting radially inwardly from said free end. 
     According to an embodiment, said clamp system  603  comprises a latch mechanism for gripping a portion of the surgical instrument  610 . Thereby, the grip action against a portion of the surgical instrument  610  is exerted by means of tightening of the latch mechanism. 
     According to an embodiment, said clamp system  603  comprises a threaded coupling for gripping a portion of the surgical instrument  610 . Thereby, the grip action against a portion of the surgical instrument  610  is exerted by means of tightening the threaded coupling. 
     According to an embodiment, said at least one clamping abutment portion  616  of the clamp system  603  comprises a clamping abutment surface  619  that is designed to elastically bias in the radial direction R-R against the shaft  611  of the surgical instrument  610  with the purpose of positioning the tip protector  601  against the shaft  611 . Thereby, thanks to such an elastic bias in the radial direction R-R, said clamping abutment surface  619  is in frictional contact with the shaft  611 . Thanks to said frictional contact, it is possible to prevent unwanted sliding of the tip protector  601  and particularly of the clamp system  603  thereof on the shaft  611 . 
     According to an embodiment, said at least one clamping abutment portion  616  of the clamp system  603  corresponds to said one or more further shaft abutment surfaces  629 ′,  629 ″. 
     As mentioned above, said tip protector  601  preferably comprises a distal through opening  605 , preferably located at or near the distal end  604  of the tip housing  602 . According to an embodiment, said at least one protective distal wall  608  of the tip housing  602  delimits said distal through opening  605  of the tip protector  601 . Said distal through opening  605  of the tip housing may serve for drainage of liquids from the housing cavity  624  of the tip housing  602  of the tip protector 
     As mentioned above, said distal through opening  605  has an opening size  606  that is adjustable. Thereby, said distal through opening  605  can be made through for at least the instrument tip  612 , to pass through said distal through opening  605  of the tip housing  602  of the tip protector  601 . In other words, the size  606  of the distal through opening  605  of the tip housing  602  is adjustable and can be adjusted with the purpose of make the distal through opening  605  a through passage for at least the tip  612  of the surgical instrument  610 . Preferably, said distal through opening  605  is a through opening also a portion of the shaft  611  of the surgical instrument  610 . The tip protector can thereby be positioned and repositioned at various locations along the shaft  611  of the surgical instrument. According to a preferred embodiment, the term “opening size  606 ” as used herein refers to the dimensions of the distal through opening  605  that are evaluated in a direction transverse to the longitudinal direction X-X, and preferably along the radial direction R-R. According to a preferred embodiment, the term “opening size  606 ” as used herein refers to the diameter of the distal through opening  605 . Thanks to such a distal through opening  605 , the tip housing  602  of the tip protector may become a through channel for the instrument tip  612  and preferably also for at least a distal portion  613  of the shaft  611 , and more preferably for the shaft  611  in its entirety. Thanks to the size adjustment of such a distal through opening  605  of the tip housing  602 , the tip housing  602  may form a longitudinal abutment for the instrument tip  612  and by means of adjustment of the size  606  of the distal through opening  605  the tip housing  602  becomes a through longitudinal passage for the instrument tip  612 . 
     According to a preferred embodiment, the size  606  of the distal through opening  605  is adjustable and can be set in an abutment configuration wherein said tip abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ abut against said instrument tip  612 , and in a pass-through configuration wherein at least said instrument tip  612  passes through said distal through opening  605 . When in the pass-through configuration the tip abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ of the tip housing  602  may abut against the shaft  611  of the surgical instrument  610 . 
     According to an embodiment, the opening size  606  of the distal through opening  605  can be adjusted so that to temporary close said distal through opening  605 . The distal through opening  605  can be then adjusted in size to open. According to an embodiment, when the opening size  606  of the distal through opening  605  can be adjusted so that to temporary close said distal through opening  605 , this configuration may correspond to an abutment configuration where said tip abutment surfaces surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ abut against said instrument tip  612 . 
     When in operative conditions, the tip protector  601  is positioned in a certain location so that the instrument tip  612  of the surgical instrument  610  approaches the proximal mouth  622  of the though channel  618  defined by said clamp system  603 . Then, the tip protector  601  is retracted along the longitudinal direction X-X along the shaft  611  of the surgical instrument  610  towards the proximal portion  614  of the shaft  611 , as indicated by the retraction arrows X 1  of  FIG.  9   . Thereby, the clamp system  603 , preferably the sleeve  617  and the elastic tongue  615 , of the tip protector  601  slidingly fits the distal portion  613  of the shaft  611  of the surgical instrument  610  and the articulated instrument tip  612  approaches the proximal through opening  623  of the housing cavity  624  of the tip housing  602  of the tip protector  601 . Then, the tip protector  601  is further retracted along the longitudinal direction X-X along the shaft  611  of the surgical instrument  610  towards the proximal portion  614  of the shaft  611 , as indicated by the retraction arrows X 1  of  FIG.  9   . 
     Thereby, the at least one abutment portion  616  of the clamping system  603  abuts against the shaft  611  of the surgical instrument  610  exerting the elastic grip action against the shaft  611  to firmly position the tip protector  610  against the shaft  611 . At this point, the size  606  of said distal through opening  605  of the tip housing  602  may be adjusted, in particular it may be increased. 
     Thereby, the distal through opening  605  becomes a pass-through opening of the instrument tip  612  as the size  606  of the distal through opening  605  when in the pass-through configuration exceeds the radial size of the instrument tip  612 . Then, the tip protector  601  is further retracted along the longitudinal direction X-X along the shaft  611  of the surgical instrument  610  towards the proximal portion  614  of the shaft  611 , as indicated by the retraction arrows X 1  of  FIG.  9   . 
     The tip protector  601  can thereby be repositioned, i.e. against the shaft  611 , at a new location that is for example located proximal along the shaft  611  to the previous location, thereby exposing the instrument tip  612  distally in respect of the tip housing  602 , in other words: the articulated instrument tip  612  protrudes in the longitudinal direction X-X distally from the protective distal wall  608  of the tip housing  602 . 
     Thanks to such a tip protector  601  it is possible to expose the instrument tip  612  that was previously covered by the same tip protector  601  and in particular by the tip housing  602 , without requiring to move the surgical instrument  610  away from the operatory volume  625  and therefore without requiring to reposition the surgical instrument  610  and the instrument tip  612  thereof within the operatory volume  625 . Thanks to such a tip protector  601  the exposure of the instrument tip  612  is achieved by means of retraction of the tip protector  601  relatively to the instrument shaft  611 . 
     At the same time, by means of retracting the tip protector  601  having the adjustable distal through opening  605  towards the proximal end  614  of the shaft  611  while the tip protector  601  is still fitted onto the shaft  611 , it is allowed to reduce the volume of free space around the surgical instrument  610  that is needed in order to exposing the instrument tip  612 . In particular, as the tip protector  601  is repositionable in a retracted position against and along the shaft  611 , in order to expose the instrument tip  612  it suffices to retract the tip protector  601  accordingly, thereby avoiding the need of extracting the tip protector from the distal end of the shaft. Thereby, the tip protector  601  makes the exposure of the instrument tip  612  quicker and safer when compared to known solutions. Moreover, the safety of the surgery is further enhanced as it is made possible to position the instrument tip  612  at the desired location before the removal of the tip protector  601  from the instrument tip  612 . 
     Moreover, it is made possible to cover or to protect the instrument tip  612  by means of said tip protector  601  before moving the surgical instrument  610  away from the operatory volume  625 . The covering of the instrument tip  612  is achieved by advancing the tip protector  601  along the shaft  611  away from the proximal end  614  of the shaft  611 , towards and beyond the distal portion  613  of the shaft  611 , as indicated by the arrow X 2  of  FIG.  10   . In this configuration, clamping system  603  abuts against the shaft  611  at a location which is near to the instrument tip  612 . Moreover, when the tip protector  601  covers the articulated instrument tip  612 , the at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of the housing  602  abuts against the articulated instrument tip  612  from opposite sides thereof, exerting a constraining action, which brings the links forming the articulated instrument tip  612  in a predefined configuration. The predefined configuration may be aligned to the shaft  611 . The provision of such one or more shaft abutment surfaces  629 ′,  629 ″ abutting against the shaft  611  at a location near to the instrument tip  612  allows for strengthen the constraining action exerted by the at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of the tip protector  601 . 
     According to an embodiment, the tip protector  601  transmits any loads to the shaft  611  avoiding to overloading the instrument tip  612 . For example, any loads applied onto the distal wall  608  of the tip protector  601  is transmitted to the instrument shaft  611 . Thereby, the safety of the surgery for the patient and the integrity of the instrument tip  612  are greatly enhanced. 
     According to an embodiment, the tip protector  601  is made of a molded rigid plastic material, for example through injection molding. Thereby the tip protector  601  can be disposable [i.e. single use] and at the same time unexpensive to manufacture. 
     According to an embodiment, the tip protector  601  is made of a material that can be sterilized, for example with conventional sterilization procedures for surgery. 
     According to an embodiment, said tip protector  601  comprises a control interface  604  for controlling the adjustment of the opening size  606  of said distal through opening  605 . By acting onto said control interface  604 , it is possible to adjust the size  606  of the distal through opening  605 . According to an embodiment, said control interface  604  is connected to at least one transmission element  626  that is in turn connected to at least one portion of the tip housing  602 , so that the at least one transmission element  626  transmits a control action from the control interface  604  to the tip housing  602  with the purpose of adjusting the distal through opening  605  of the tip protector  601 . According to an embodiment, said control interface  604  comprises at least one interface surface  604 ′,  604 ″, and preferably two opposite interface surfaces  604 ′,  604 ″ located opposite one another in respect of the tip housing  602 , and the at least one transmission element  626  comprises a first transmission arm  626 ′ and a second transmission arm  626 ″, wherein each interface surface  604 ′ or  604 ″ is integrally connected to one respective of said transmission arms  626 ′ or  626 ″. According to an embodiment, said control interface  604  comprises at least two opposite interface surfaces  604 ′,  604 ″ located opposite one another in respect of the tip housing  602 , wherein at least one of the at least two interface surfaces  604 ′,  604 ″ is associated to an elastic element  627 , for example an elastic arm  627 ′ or  627 ″ integrally connected to a respective interface surface  604 ′,  604 ″, so that the elastic element  627  biases said at least one of the at least two interface surfaces  604 ′,  604 ″ towards a predefined position. Preferably, said predefined position towards which the at least one elastic element  627  biases the at least one interface surface  604 ′,  604 ″ determines the tip housing  602  to assume said abutment configuration. According to an embodiment, said two opposite interface surfaces  604 ′,  604 ″ are designed to be pressed one towards the other by the fingers of an operator. The pressure manually applied onto said two opposite interface surfaces  604 ′,  604 ″ determines the elastic deformation, i.e. bending, of the at least one elastic element  627  and at the same time displaces a portion of the tip housing  602  by means of said at least one respective transmission element  626 . Preferably, said tip housing  602  is formed by at least two parts  602 ′ and  602 ″ or tip half-housings  602 ′ and  602 ″ that cooperate together to define said tip hosing  602 , and wherein each of said two opposite interface surfaces  604 ′,  604 ″ is associated to a respective tip half-housing  602 ′,  602 ″ through a respective transmission element  626 ′,  626 ″. The paths described by said transmission elements  626 ′ and  626 ″ may overlap along the centerline x-x of the tip protector  601 , so that applying a pressure onto said first interface surface  604 ′ determines the displacement of the first tip half housing  602 ′ that is located on the opposite longitudinal side of the tip protector  601  in respect of the first interface surface  604 ′. 
     According to an embodiment, said tip protector  601  is substantially a clip having the size  606  of the distal opening  605  elastically adjustable and the abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ elastically preloaded in closure [i.e. toward each other]. 
     Said at least two elastic arms  627 ′,  627 ″ for biasing the respective interface surface  604 ′,  604 ″ and/or abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ may be integrally fixed one to the other in a respective fixing root  628  thereof so that the respective interface surfaces  604 ′ and  604 ″ substantially protrude in the radial direction R-R preferably forming a bend on the body of the respective elastic arm  627 ′,  627 ″, from each of the surface interfaces  604 ′,  604 ″ extends a respective transmission arm  626 ′,  626 ″ that extends towards the centerline x-x of the tip protector  601  and that connects to a respective tip half-housing  602 ′,  602 ″ located on the opposite longitudinal side in respect of the respective interface surface  604 ′ or  604 ″. 
     According to an embodiment, said tip protector  601  is made of two pieces  601 ′ and  601 ″ locally integrally fixed one to the other in said fixing root  628  so that the elastic arms  627 ′ and  627 ″ elastically bias the respective interface surfaces  604 ′ and  604 ″ to protrude radially away from the centerline x-x, and wherein each interface surface  604 ′,  604 ″ is connected to a respective tip half-housing  602 ′,  602 ″ by means of a respective transmission arm  626 ′,  626 ″, and wherein the tip half-housings  602 ′,  602 ″ together define preferably partially said distal through opening  605 , and at the same time the elastic arms  627 ′ and  627 ″ elastically bias the respective abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″″ towards each other. 
     Fixing means may be provided to fix said two pieces  601 ′ and  601 ″ of said tip protector  601 , for example said fixing means comprises: at least one rivet, and/or at least one screw, and/or at least one nail, and/or glue and/or the like. 
     According to an embodiment, said tip protector  601  comprises one or more stroke end portions  633  for limiting the maximum size  606  of the distal opening aperture  605 . Thereby, it is prevented to abut overstress the elastic elements of the tip protector  601 . According to an embodiment, said one or more stroke end portion  633  are at least two facing stroke end portions  633 ′ and  633 ″ preferably each of said at least two facing stroke end portions  633 ′ and  633 ″ is located opposite to a respective interface surface  604 ′  604 ″ of the tip protector  601 . According to an embodiment, each of said at least two facing stroke end portions  633 ′ and  633 ″ is located on the same piece of material of a respective interface surface  604 ′  604 ″ and behind it. According to an embodiment, said one or more stroke end portions  633 ′ and  633 ″ are in form of protrusions extending towards the tip protector centerline x-x. According to an embodiment, a through longitudinal passage  634  is defined in said stroke end portions  633 ′ and  633 ″ to receive the shaft  611  of the surgical instrument  610 . 
     According to an embodiment, said tip protector  601  comprises a locking mechanism  607  for temporary limiting the distal opening size  606  within a predefined size opening value that prevents the instrument tip  612  from passing through the distal through opening  605  of the tip housing  602 . Thanks to the locking mechanism  607  it is possible to temporary block the maximum size of the distal through opening  605  when the tip protector  601  has the at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ in abutment against the articulated instrument tip  612  and/or the shaft abutment surfaces  629 ,  629 ′ in abutment against the shaft  611  with the purpose of exerting said constraining action. At the same time, that allows for a more firm positioning of the tip protector  601  against the shaft  611 . Thereby the size  606  of the distal through opening  605  is independent from the clamping action of the clamping system  603 , and that may allow an improved clamping force. 
     Moreover, thanks to the provision of said locking mechanism  607 , the occurrence of an unwanted motion of the instrument tip  612  in the radial direction R-R avoids adjusting the size  606  of the distal through opening  605 . Preferably, said locking mechanism  607  comprises at least one locking tooth  630  located on a tip half-housing  602 ′ or  602 ″ near the distal through opening  605  that engages with a respective locking notch  631  of the other tip half-housing  602 ″ or  602 ′. Preferably, each half housing has one locking tooth. Preferably, said locking mechanism  607  comprises further a cam surface  632  to favor the engagement and/or the disengagement of said at least one locking tooth  630  with a respective locking notch  631  though roll of a portion of one of the tip half housing  602 ′ or  602 ″ over said cam surface  632  that is located on the other tip half-housing  602 ″ or  602 ′. Thereby the cam surface  632  while rolling defines a fulcrum for engaging and/or disengaging said tip half-housings  602 ′ and  602 ″. According to an embodiment, the locking tooth  630  during the process of closure of the distal opening is elastically biased against said cam surface  632 . According to a preferred embodiment, when the locking mechanism  607  is activated, it resists against the elastic bias exerted by arms of the tip protector  601 , so that when locked the tip protector  601  is elastically deformed. 
     According to an embodiment, said clamping system  603  of the tip protector  601  comprises an anti-twist device  635  designed to avoid or at least to reduce the roll or twist or pivot of the instrument shaft  611  in respect of the tip protector  601  about the longitudinal direction X-X while the tip protector  601  is clamped to the instrument shaft  611 . 
     According to an embodiment, said anti-twist device  635  comprises at least one o-ring  638  fitted onto the shaft  611  and received with clearance in a chamber  636  of the through channel  618  of the clamping system  603 ; said chamber  636  has walls defining at least a proximal o-ring stroke end  637 ′ and a disal o-ring stroke end  637 ″, each acting as stroke end wall for the o-ring  638 , wherein near or at one of the o-ring stroke ends  637 ′ or  637 ″ the walls of the chamber  636  define a narrower through passage  618 ′ that pinch the o-ring  638  thereby preventing through the body of the o-ring  638  the relative roll or twist or pivot of the shaft  611  within said through passage  618  of the clamping system  603 . Preferably, said proximal o-ring stroke end  637 ′ defines the narrower through passage  618 ′. The term “narrower through passage” does not necessarily means that is the narrowest section of the through channel  618 , although it can be according to some embodiments. 
     According to an embodiment, said anti-twist device  635  comprises one or more guiding elements, such as one or more guiding grooves or guiding protrusions. designed to guide the tip protector  601  along the shaft  611  along a predetermined direction. The shaft  611  may suitably comprise one or more counter-guiding elements, such as guiding protrusions or guiding grooves designed to engage with the one or more guiding elements of the tip protector  601 . The predetermined direction may be a straight direction parallel to longitudinal extension of the shaft X-X. The predetermined direction may be a helicoidal direction winding around the shaft  611  and extending along longitudinal extension of the shaft X-X. The provision of such one or more counter-guiding elements of the shaft  611 , designed to engage with the one or more guiding elements of the tip protector  601  allows an enhanced control over the relative displacement of the tip protector  601  and the shaft  611 , allowing to define at least one repositioning path for the tip protector  601  with respect to the shaft  611  and/or the instrument tip  612 , thereby preventing the tip protector  601  to rotate about the longitudinal direction X-X without control during repositioning of the tip protector  601  along the shaft  611  and/or against the instrument tip  612 . In this way, when the tip protector  601  is moved distally from the shaft  611  to abut against the instrument tip  612 , it is possible to ensure that the tip protector  601  abuts against a predetermined portion of the instrument tip  612 . 
     According to an embodiment, at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of a pair of opposite tip abutment surfaces is made as a single piece with at least one shaft abutment surface  629 ′,  629 ″ of a pair of opposite shaft abutment surfaces. Elastic elements may be also provided between said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of a pair and said at least one shaft abutment surface  629 ′,  629 ″ of a pair. The provision of the locking mechanism may lock the relative position of said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of a pair and at least one shaft abutment surface  629 ′,  629 ″ of a pair, acting against the elastic preload provided by said elastic element thereby constraining a respective half of the tip protector  601  in an elastically deformed configuration. 
     According to an embodiment, at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of a pair of opposite tip abutment surfaces is made as a single piece with at least one clamping abutment portion  616  of a pair of opposite clamping abutment portions of the clamping system of the tip protector  601 . Thereby, a pair of opposite clamping abutment portions may be provided. Elastic elements may be also provided between said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of a pair and said at least one clamping abutment portion  616  of a pair. The provision of the locking mechanism may lock the relative position of said at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ of a pair and said at least one clamping abutment portion  616  of a pair, acting against the elastic preload provided by said elastic element thereby constraining a respective half of the tip protector  601  in an elastically deformed configuration. 
     According to a general embodiment, an assembly  600  comprises at least one tip protector  601  according to any one of the embodiments described above. 
     Said assembly  600  also comprises at least one surgical instrument  610  having a shaft  611  according to any one of the embodiments described above. Preferably, said assembly  600  comprises a surgical instrument  610  having a shaft  611  extending along a longitudinal direction X-X and an articulated instrument tip  612  at the distal portion  613  of the shaft  611 . 
     Said articulated instrument tip  612  is articulated with respect to the instrument shaft  611  defining at least one degree of freedom. 
     The tip protector  601  is fitted onto the shaft  611  of the surgical instrument  610 , so that the tip protector  601  is repositionable in various locations along the shaft  611 . 
     The tip housing  602  comprises at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ suitable for abut against the instrument tip  612  from opposite sides thereof for exerting a constraining action on the instrument tip  612  at least in a direction, which is transversal to the longitudinal direction X-X of the shaft  611 , with the purpose to block at least one of the degrees of freedom of said articulated instrument tip  612 . 
     According to a preferred embodiment, the articulated instrument tip  612  has at least one degree of freedom of grip G, wherein said constraining action exerted by said at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ constrains the degree of freedom of grip G in a predefined configuration. 
     According to a preferred embodiment, the articulated instrument tip  612  has at least one between pitch P and yaw Y degree of freedom, and preferably both, wherein said constraining action exerted by said at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ constrains the at least one the degree of freedom of pitch P and/or yaw Y in a predefined configuration. 
     According to a preferred embodiment, said predefined configuration is a straight configuration aligned to the longitudinal direction X-X of the instrument shaft  611 , so that said constraining action exerted by said at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ constrains the articulated instrument tip  612  the in a straight configuration aligned to the longitudinal direction X-X of the instrument shaft  611 . 
     According to a preferred embodiment, said instrument tip  612  of the surgical instrument  610  comprises one or more tendons  647 ,  647 ′,  648 ,  648 ′,  649 ,  649 ′ for articulating said one or more degree of freedom of the articulated instrument tip  612 , wherein said constraining action exerted by the at least one abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ blocks at least one of the degrees of freedom of said articulated instrument tip  612  even when said one or more tendons  647 ,  647 ′,  648 ,  648 ′,  649 ,  649 ′ apply a tensile load directed to actuate at least one of the degrees of freedom of said articulated instrument tip  612 . That is achievable for example thanks to the provision of at least one suitably tuned elastic element of the tip protector  601 , which makes the constraining action an elastic constraining action, and/or thanks to the provision of a locking mechanism of the tip protector  601 . 
     As mentioned above, the at least one tip protector  601  is repositionably fitted onto the shaft  611  of the at least one surgical instrument  610 . 
     According to an embodiment, said shaft  611  of the surgical instrument  610  comprises a counter-clamping portion  639  suitable for the clamping system  603 , preferably said abutment portion  616  of the clamping system  603 , to abut thereon and/or there against in order to avoid the tip protector  601  to slip out from the shaft  611 . 
     According to an embodiment, said counter clamping portion  639  of the shaft  611  of the surgical instrument  610  has a surface treatment for enhancing the longitudinal friction and thus the adhesion with the clamping system  603 . Preferably, said surface treatment is made by knurling. 
     According to an embodiment, said counter clamping portion  639  of the shaft  611  has a protuberance for engaging with, for example in an undercut manner, the clamping system  603  of the tip protector  601 . The counter clamping portion of the shaft may engage with the clamping portion of the tip protector according to any suitable strategies, for example by means of form-fitting, and/or threaded coupling, and/or force-fitting, and/or the like. 
     According to a general embodiment, a master-slave robotic surgery system  620  comprises at least one assembly  600  according to any one of the embodiments described above and a master console  621  for controlling the surgical instrument  610  of said assembly  600 . 
     In the following will be described a method of repositioning of a tip protector  301 . 
     A method for repositioning a tip protector  601  comprises the steps of:
         positioning a tip protector  601  against a first portion  641  of the shaft  611  of a surgical instrument  610  that has an instrument tip  612  near the distal portion  613  of the shaft  611 ;   applying an action  640  onto an interface  604  of the tip protector  601  so that to increase the size  606  of a distal through opening  605  of said tip protector  601 , thereby the distal through opening  605  becomes a through passage for at least the instrument tip  612 ;   moving the tip protector  601  along the shaft  611 ;   repositioning the tip protector  601  against a second portion  642  of the shaft  611 .       

     According to a preferred mode of operation, the step of repositioning involves the step of releasing the action  640 . Preferably, said action  640  is a manual action  640 . 
     According to a mode of operation, the second portion  642  of the shaft  611  is closer to a proximal end  614  of the shaft  611  that the first portion  641  of the shaft  611  along the longitudinal direction X-X. 
     According to a mode of operation, the second portion  642  of the shaft  611  is farer to a proximal end  614  of the shaft  611  that the first portion  641  of the shaft  611  along the longitudinal direction X-X. 
     According to a mode of operation, the method comprises the step of further repositioning the tip protector  601  against the shaft  611  of the surgical instrument  610 . 
     According to a mode of operation, the step of moving comprises the step of retracting the tip protector  601  along the shaft  611 . 
     According to a mode of operation, the step of moving comprises the step of advancing the tip protector  601  along the shaft  611  towards the instrument tip  612 . 
     According to a mode of operation, the method comprises the step of covering the instrument tip  612  by means of said tip protector  601 . Thereby the articulated instrument tip  612  is received within the cavity of the housing  602  and the at least one abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ′″ exerts said constraining action on the instrument tip  612 , locking at least one, and preferably all the degrees of freedom of the articulated instrument tip  612 . 
     According to a mode of operation, the method comprises the step of constraining the articulated instrument tip  612  in a predefined configuration. 
     According to a mode of operation, the step of constraining comprises constraining the articulated instrument tip  612  in a straight configuration aligned to the longitudinal direction X-X of the shaft  611 . 
     According to a preferred mode of operation, the method is performed by means of an assembly  600  according to any one of the embodiments described above. 
     In the following will be described a method for constraining an articulated instrument tip  612  by means of a tip protector  601 . 
     A method for constraining an articulated instrument tip  612  comprises the following steps:
         positioning a tip protector  601  having a tip housing  602  comprising at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ onto an articulated instrument tip  612  so that the at least one tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ abuts against the instrument tip  612  from opposite sides of the tip  612 ;   exerting a constraining action on the instrument tip  612  at least in a direction, which is transversal to the longitudinal direction X-X of the shaft  611 ,   blocking at least one of the degrees of freedom of said articulated instrument tip  612 .       

     According to a mode of operation, the step of positioning comprises the step of abutting at least a pair of opposite tip abutment surface  609 ′,  609 ″,  609 ′″,  609 ″″ against a link of the instrument tip  612  from opposite sides of the articulated tip  612 . 
     According to a mode of operation, the step of exerting comprises the step of abutting one or more further abutment surfaces  629 ′,  629 ″ against the shaft  611 , in order to act as reference points for the tip abutment surfaces  609 ′,  609 ″,  609 ′″,  609 ″. 
     According to a mode of operation, the step of exerting comprises the step of exerting an elastic constraining action. 
     According to a mode of operation, the step of blocking comprises the step of mechanically lock the tip protector  601  in place. 
     According to a mode of operation, the step of blocking comprises the step of applying an actuation load on at least one of the degrees of freedom of the instrument tip  612 . 
     According to a mode of operation, the method for constraining comprises one or more of the steps described above with reference to the method of repositioning. 
     According to a mode of operation, the method for constraining is carried out by means of a tip protector  601  and/or an assembly  600  according to any one of the embodiments described above. 
     Thanks to the features described above provided either together or disjointly in particular embodiments, it is allowed to respond to the above-mentioned needs providing the above cited advantages, and in particular:
         it is possible to reposition the tip protector against the shaft of the surgical instrument;   it is possible to expose the instrument tip without for this reason requiring to reposition the surgical instrument within or away the operatory volume;   the tip protector can be sterilized or it is disposable;   the degrees of freedom of the articulated instrument tip are freezed in a constrained configuration during any attempt to actuate said degrees of freedom;   when the articulated instrument tip is exposed out of the tip protector, i.e. when the tip protector is retracted, the articulated instrument tip is in a known pose and that may be beneficial when the surgical instrument is a slave surgical instrument of a robotic platform controlled by a mechanically ungrounded/unconstrained master input tool;   the locking mechanism may constrain the tip protector in an elastically deformed configuration, where the abutment surfaces abut against the articulated instrument tip exerting a constraining action against the instrument tip.       

     Those skilled in art may make many changes and adaptations to the embodiments described above or may replace elements with others, which are functionally equivalent in order to satisfy contingent needs without however departing from the scope of the appended claims. 
     REFERENCE LIST 
       600  Assembly 
       601  Tip protector 
       601 ′ First piece of the tip protector 
       601 ″ Second piece of the tip protector 
       602  Tip housing of the tip protector 
       602 ′ First tip half-housing of the tip protector 
       602 ″ Second tip half-housing of the tip protector 
       603  Clamping system or clamp system of the tip protector 
       604  Control interface of the tip protector 
       604 ′ First interface surface of the tip protector 
       604 ″ Second intefrace surface of the tip protector 
       605  Distal through opening of the tip protector 
       606  Opening size, or size of the distal through opening 
       607  Locking mechanism 
       608  Distal protective wall of the tip protector 
       609 ′,  609 ″ Abutment surface of the tip housing 
       609 ″,  609 ″″ Abutment counter-surface of the tip housing 
       610  Surgical instrument 
       611  Shaft of the surgical instrument 
       612  Articulated instrument tip of the surgical instrument 
       613  Distal portion of the shaft 
       614  Proximal end of the shaft 
       615  Elastic tongue of the clamping system 
       616  Abutment portion of the clamping system 
       617  Sleeve of the clamping system 
       617 ′ First half-pipe of the clamping system 
       617 ″ Second half-pipe of the clamping system 
       618  Through channel of the clamping system 
       619  Clamping abutment surface of the clamping system 
       620  Robotic surgery system 
       621  Master console or master controller of the robotic surgery system 
       622  Proximal channel mouth of the through channel 
       622 ′ Distal channel mouth of the through channel 
       623  Proximal through opening of the tip housing 
       624  Housing cavity of the tip housing 
       625  Operating volume 
       626  Transmission element 
       626 ′ First transmission arm 
       626 ″ Second transmission arm 
       627  Elastic element 
       627 ′ First elastic arm 
       627 ″ Second elastic arm 
       628  Root portion 
       629 ′,  629 ″ Shaft abutment surfaces of the tip protector 
       630  Locking tooth of the locking mechanism 
       631  Locking notch of the locking mechanism 
       632  Cam surface of the locking mechanism 
       633 ,  633 ′,  633 ″ End stroke portion 
       634  Through longitudinal passage 
       635  Anti-twist device, or anti-roll device 
       636  Chamber 
       637 ′ O-ring proximal stroke end of the anti-twist device 
       637 ″ O-ring distal stroke end of the anti-twist device 
       638  O-ring of the anti-twist device 
       639  Counter-clamping portion of the shaft 
       640  Applied action, or action 
       641  First portion of the shaft 
       642  Second portion of the shaft 
       643 ,  644 ,  645 ,  646  Links of the surgical instrument 
       647 ,  647 ′,  648 , Actuation cables of the surgical instrument, or tendons 
       648 ′,  649 ,  649 ′ 
     X-X Longitudinal direction 
     R-R Radial direction 
     C-C Circumferential direction 
     x-x Centerline of the tip protector 
     X 1  Direction of retraction 
     X 2  Direction of advance 
     P Pitch degree of freedom of the instrument tip 
     Y Yaw degree of freedom of the instrument tip 
     G Grip degree of freedom of the instrument tip