the illustration in the drawings is schematically . in different drawings , similar or identical elements are provided with similar or identical reference signs . fig1 a shows a schematic illustration of the bone pin 100 according to an exemplary embodiment . the bone pin 100 comprises a shaft region 101 and a base region 102 . the shaft region 101 comprises a plurality of protrusions 103 which roughly have the general shape of a triangle . a single one of the protrusions is depicted in greater detail in fig1 h . the base region 102 may be adapted to fit onto a corresponding ultrasonic device . fig1 b shows an enlarged view of the sonic pin 100 of fig1 a . in particular , it shows a cross section along line d - d of fig1 a , i . e . a cross section of the base region 102 . in the centre of the cross section of fig1 b a hole 104 is shown which might be adapted to accommodate a portion of the ultrasonic device , e . g . a sonotrode of the ultrasonic device . furthermore , it can be seen in fig1 b that the cross section comprises rounded regions 105 and substantially plane regions 106 . fig1 c shows another enlarged view of the sonic pin 100 of fig1 a . in particular , it shows a cross section along line c - c of fig1 a , i . e . also a cross section of the base region 102 . in the centre of the cross section of fig1 c the hole 104 is shown . furthermore , in fig1 c the rounded regions 105 and the substantially plane regions 106 can be seen . fig1 d shows another enlarged view of the sonic pin 100 of fig1 a . in particular , it shows a cross section along line b - b of fig1 a , i . e . a cross section of the shaft region 101 . also this cross section shows further rounded regions 107 and further substantially plane regions 108 . in particular , the further plane regions 108 may be part of the protrusions 103 . fig1 e shows another enlarged view of the sonic pin 100 of fig1 a . in particular , it shows a cross section along line a - a of fig1 a , i . e . a cross section of the shaft region 101 . also this cross section shows the further rounded regions 107 and the further substantially plane regions 108 . fig1 f shows another enlarged view of the sonic pin 100 of fig1 a . in particular , it shows a detailed view of the portion which corresponds to the circle labeled f in fig1 a , i . e . of the base region 102 . in particular , fig1 f shows the transition portion 109 between the base region and the shaft region . fig1 g shows an even more enlarged view of the portion of fig1 f , in which the transition region can be seen more clearly . in particular fig1 g also shows a part of a protrusion 103 in more detail . the protrusions of the embodiment shown in fig1 have an overall shape , which is roughly triangular . the single triangles are formed by tongues 110 , 110 and 112 which do have a different length along the axis of the sonic pin 100 . due to the different lengths a roughly triangular shape of the protrusions results . such a shape may be suitable to hinder the flowing of liquefied material along the axis of the sonic pin 100 and promote a more perpendicular spreading of the liquefied material , i . e . a spreading which promote the flowing of the liquefied material into cavities or pores which are formed in bone material of human or animal bones . fig1 h shows another enlarged view of the sonic pin 100 of fig1 a . in particular , it shows a detailed view of the portion which corresponds to the circle labeled e in fig1 a , i . e . a protrusion formed in the shaft region 101 . as well as in fig1 g the roughly triangular shape of the protrusion can be seen in fig1 h , which shape is formed by the tongues 110 , 111 , and 112 having different lengths . furthermore , it can be seen in fig1 h that the orientation of the triangular protrusion 103 are altering , i . e . after a first triangular protrusion 113 having its base length in fig1 h at the upper side , a consecutive triangular protrusion 114 has its base length at the bottom side , leading to channel regions 115 between the single triangles , which channels 115 may be suitable to direct the flow of liquefied material . fig1 i shows another enlarged view of the sonic pin 100 of fig1 a . in particular , it shows a detailed cross sectional view along line g - g in fig1 a , i . e . a cross sectional view of the base region 102 . in particular , the hole 104 in the base region can be seen , in which a tip of a sonotrode or an implantation device applicator may be inserted . a bone pin according to an exemplary embodiment may be used in a operation process for fixation of a broken or splintered bone , the procedure comprising the following steps . drilling a hole in which the bone which has to be fixed afterwards the bone pin is implemented into the drilled hole . in case the bone is a porous bone , i . e . comprising porous material it may not necessary to pre drill a hole . preferably , this is done using an so - called pin applicator . afterwards the pin applicator is removed and an ultrasonic device is arranged at the base region of the bone pin , i . e . in the hole which is shown as 104 in fig1 . when the ultrasonic device is switched on the bone pin starts to oscillate and the protrusions arranged on the shaft of the bone pin come into contact with the surrounding bone so that portions of the protrusions are sheared off by shearing forces from the bone pin , whereby they are liquefied . due to the providing of a plurality of protrusion comprising tongues only small parts of the hole shaft of the bone pin are contacting the bone and are sheared off or liquefied . the liquefied material of the bone pins starts to penetrate pore spaces of the bone . when the ultrasonic device or ultrasonic driver is switched off the liquefied material , e . g . the polymer , cools rapidly , resulting in a stable joint after only a few seconds and may form a positive locking . in case the bone pin should be removed again a bone pin remover may be used . such a pin remover may comprise a portion similar a crown drill , which drill is placed above the bone pin which is to be removed . then the remover is drilled into the bone . the cutting hull or cutting sheath of the crown drill cuts into the bone and also cuts a thread into the bone cut in the cutting hull . this threading may provide a positive locking between the driller and the bone portion to be removed so that afterwards the remover may be used to break the bone portion including the bone pin to be removed . fig2 shows a schematic illustration of an ultrasonic device 200 which can be used in combination with a bone pin according to an exemplary embodiment of the invention . the ultrasonic device comprises a hand piece 201 which has a shape which is adapted to be gripped by a human , e . g . a physician implementing the bone pin . furthermore , the ultrasonic device comprises a mounting part 202 in which a sonotrode 203 can be inserted . furthermore , a cable 204 for supplying the ultrasonic device with energy and a switch 205 for turning the ultrasonic device on and off is shown in fig2 . fig3 shows schematic illustrations of an implantation device applicator 300 according to an exemplary embodiment of the invention . fig3 shows a perspective view of the implantation device applicator 300 . the implantation device applicator 300 comprises a tip 301 and a front region 302 . furthermore , the implantation device applicator 300 comprises a main body 303 and an end region 304 . fig4 shows a schematic view of an implantation device remover 400 according to an exemplary embodiment . the implantation device remover 400 comprises a handle 401 , which is in the case of fig4 a simple t - piece . the handle 401 serves for a good grip of a person using the implantation device remover , e . g . a surgeon . the implantation device remover 400 further comprises a drilling region 402 which comprises at a tip of the drilling region 402 a hollow part . furthermore , the tip comprises an edge 403 which is formed like a saw , e . g . comprises cutting teeth . in total the implantation device remover 400 has a size which is suitable for good gripping by the surgeon , e . g . the handle is about 100 mm wide . the diameter of the drilling region 402 is adapted to the diameter of the implantation device which is to be removed . in particular , the inner diameter of the hollow part may be a little greater than the diameter of the implantation device , e . g . a bone pin . summarizing it may be seen as one aspect of the present invention to provide a bone pin having a shaft comprising a plurality of protrusions . due to the protrusions only small parts of the bone pins are sheared off when ultrasonic energy is applied to the bone pin , leading to the effect that only a small total power is used to achieve a suitable energy density at the protrusions to liquefy the same . thus , the total power , i . e . energy per time , may be reduced which may reduce the energy input into the bone the bone pin is applied to , so that damage to the bone may be reduced . it should be noted that the term “ comprising ” does not exclude other elements or steps and the “ a ” or “ an ” does not exclude a plurality . also elements described in association with different embodiments and aspects may be combined . it should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims . although the invention herein has been described with reference to particular embodiments , it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention . it is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims .
an implantation device and method for applying the same has an implantation device for implantation in a target structure such as a bone . the implantation device comprises a shaft region , wherein the shaft region has at least one protrusion . the protrusion comprises a material which is modifiable by using mechanical energy . in particular , the modifiable material may be liquefiable and / or shearable by the mechanical energy . preferably , the material may be adapted in such a way that the modifications may be achievable by a mechanical energy input which does not destroy human tissue .