The invention relates to medicine, and more particularly, to an electret
implant according to the preamble of claim 1.
BACKGROUND OF THE INVENTION
Since the 80s a new branch of medicine based on the use of short-rang5 e
static electric fields to stimulate positive biological processes in the human
body has formed and rapidly developed. The main distinguishing feature of
practical methods that are based on this concept is that electric fields are not
made by traditional electrical power sources with network or battery power, it
10 is made by autonomously functioning electret films.
Electret is a dielectric on the surface or in the bulk of which noncompensated
electric charges are preserved for a long time. These charges
produce an electric field in the space surrounding an electret. Getting together
with an implant to the human body, an electret film by its field has a local
15 effect on the damaged organ, contributing to its treatment. The electric field
of certain magnitude and sign, acting at the cellular level, is the catalyst of
reparative processes in living tissues.
US 2005/0059972 A1 discloses a pedical screw including a head and a
lower portion wherein to the head is connected a head-piece, wherein
20 different head-pieces can be connected to the pedical screw. The lower
portion of the pedical screw includes a thread for anchoring the pedical screw
in a bone.
Similarly, US 2009/0048675 A1 represents a general prior art for the
present invention, disclosing a bone fusion device, comprising a body
25 portion, a first inserting portion extending from the body portion for engaging
a first bone, and a second inserting portion extending from the body portion
for engaging a second bone.
3
A method for treatment arthrosis of the femoral head is known (see US
№ Patent 8,145,319). Through the necrotic area of the femoral head an
electric current is passed which stimulates the growth of bone tissue in the
femoral head affected by arthrosis.
To carry out this method a device for electrostimulation of the bon5 e
tissue growth is used (see US № Patent 8,145,319). The device includes a
cathode and an anode remote from each other and connected with the battery
by wires, and a control unit. The control unit and the battery are placed in an
electrically conductive housing, which acts as the anode.
10 To begin the process of electrostimulation, you must first place the
cathode in its permanent workplace. To do this it is necessary to perform a
decompression dead hole in the femoral head affected by arthrosis. An axis of
the hole is directed to an area of maximum lesion by necrosis. Then, the
cathode is placed in this hole, using a dowel of a resorbable polymer. The
15 cathode made of bare titanium wire is tightened by the dowel to the bottom of
the decompression dead hole in order to ensure maximum electrical contact
of the cathode with the necrotic area of a bone. The second function which is
provided by the dowel is to hold the cathode in the hole in its place, ensuring
conservation of the largest cathode contact with the walls and the bottom of
20 the decompression hole. For this purpose, the dowel is placed into the
decompression hole without a gap, i.e. closely. Later the dowel resolves and
the cathode grows into the bone of the femoral head forever. An electricity
wire comes out to the body surface from the bone. The electric current is
supplied through the electricity wire to the battery.
25 After placement of the cathode by the pin in its place in the hole it is
possible to begin to conduct electrical stimulation of the growth of healthy
bone tissue. For this purpose the battery potential difference is supplied to the
cathode and anode. Then, the anode is pressed against the patient's skin. A
4
catenation closure occurs at that. The electric current starts to flow between
the cathode and the anode through the body tissue of the patient, stimulating
the growth of bone tissue of the femoral head. Because the decompression
hole can be directed exactly to the area of maximum lesion by necrosis and it
may be of any desired depth, the cathode can be placed in the optimal poin5 t
of space of the femoral head, i.e. in the immediate vicinity of the zone of
necrotic lesion that ensures the highest possible therapeutic effect on bone
tissue.
A disadvantage of the method-analogue is that the electric current
10 flowing from the cathode to the anode passes through tissues: skin,
periosteum, fatty tissues and others. This leads to a loss of the battery energy
and hence it requires recharging.
Also, the electricity wire coming out of the bone from the cathode
passes through the skin of the patient outside and is a source of constant
15 infection.
In addition, the therapeutic effect of the device requires a constant
fixation of the housing-anode to the human body, creating a lot of discomfort
in everyday life.
Furthermore, during the therapeutic effect process of the device the
20 introduction of charged ions of the anode metal material leads to the
poisoning of body tissues through which the current flows.
Another method for treatment of arthrosis is known. The method
includes the periodic application (twice a day for 1 hour) of a paper plate on
the skin surface of the joint affected by arthrosis. A dielectric coating in an
25 electret state is formed on the surface of the paper plate (see
http://www.uralargo.ru/article/489, http://precession.ru/?id_page=859373 and
http://elis-deta.ru/elplast.html).
5
The disadvantage of this method for treatment of arthrosis is the
distance of the electrostatic field generated by the electret coating from the
joint lesion, which reduces the efficiency of this method-analogue, extending
the treatment duration.
In addition, the periodicity of exposure to the lesion reduces th5 e
therapeutic effect duration of the electrostatic field of the electret coating,
which also extends the treatment duration. Furthermore, when placing the
plate on the surface of the movable joint, a mashing of a dielectric layer
occurs, this leads to a loss of electret charge in it and makes the plate10
analogue unsuitable.
These drawbacks are eliminated in the closest analogue.
Authors have chosen as the closest method-analogue a method for
treatment of congenital hip joint malformation (see the USSR certificate of
authorship № 1,251,915), in which the femoral head occupies the wrong
15 position relative to the pelvis, which leads eventually to the emergence of
aseptic necrosis and degeneration of the head. During the treatment a portion
of the femur is dissected (osteotomy), after that the femoral head is fixed in
the correct position relative to the pelvis with the help of an electret implant.
The closest analogue is the electret implant according to the USSR
20 certificate of authorship № 1,251,915. The electret implant includes an
extended body with a proximal and a distal end. The dielectric coating in an
electret state is formed on its surface. Wherein the implant body is made as a
plate. The proximal end is bent and is wedge-shaped, and two reach-through
holes are made for screws at the distal end of the plate.
25 The closest method-analogue is implemented as follows: in the process
of osteosynthesis the wedge-shaped end of the plate is hammered into the
femoral head, and the distal end of the plate is tied to the second part of the
femur, providing osteosynthesis. The electret potential along the plate
6
distributes unevenly and has a maximum value in the osteotomy area (the
bone dissection area) and in the wedge-shaped end of the plate.
Because the wedge-shaped end is placed into the pathological head, it
is close to the bone pathology area. The electrostatic field generated by the
electret coating having a maximum value at the wedge-shaped end, is as clos5 e
as possible to the area of the necrotic lesion of the femoral head. This
provides an increased electrostimulation of bone structures (compared to the
previous analogue), leading to acceleration of the bone healing in the
osteotomy area and prevention of development of destructive and
10 degenerative processes in the femoral head.
Another disadvantage of the closest method-analogue is a violation of
the electret coating integrity. Hammering of the wedge-shaped end into the
femoral head is accompanied by friction of the electret coating on hard sharp
chips. These chips are generated during hammering of the wedge-shaped end
15 into the bone. During this process the violation of the electret coating
integrity occurs in the wedge-shaped end zone, where a maximum
electrostatic charge is concentrated. The violation of the electret coating
integrity leads to a rapid discharge of the electret coating in the wedgeshaped
end zone and weakening of the therapeutic action of the electrostatic
20 field (until the complete action cessation) in the bone area where there is a
maximum lesion of bone structures of the joint by the pathology.
The main purpose of the implant-analogue is osteosynthesis, i.e. a hard
fixation of the femoral head relative to the dissected part of the femur during
the treatment of the congenital disease associated with the wrong position of
25 the head relative to the pelvis. The main thing that the electrostatic field of
the electret coating works here on is osteosynthesis, i.e. stimulation of an
accretion of parts of the dissected femur in the right mutual position relative
to each other. The wedge-shaped proximal end serves here as a fastening
7
element of a temporary design to the point when parts of the femur grow
together and are able to perceive all loads of support-motor apparatus by
yourself. Then the implant is removed from the bone because of its
uselessness.
Thus, the main purpose of the electret coating on the implant surface i5 s
the optimization of osteosynthesis. The therapeutic effect of the electret
coating electrostatic field on the surface of the wedge-shaped end gives an
additional effect – an electrical stimulation of bone tissue inside the hip joint.
It takes place during the accretion of dissected parts of the femur. After the
10 implant removal the therapeutic effect of the electret coating electrostatic
field on the joint pathology stops and pathological processes may be
resumed.
Furthermore, the location of the electret implant toward the lesion of
pathological destruction in the bone may not always be optimally chosen
15 because the basic priority in choosing the direction of hammering of the
wedge-shaped end of the implant into the bone is a high accuracy of the
mutual position of connected parts of the bone (osteosynthesis). The
optimization of osteoreparation is in second place, which reduces the
efficiency of the therapeutic action of the electrostatic field on the
20 pathological lesion in the bone.
Also, hammering of the wedge-shaped end increases the intraosseous
pressure and requires drilling of several decompression holes in the bone
(near the wedge-shaped end) to decrease the bone pressure. It further
traumatizes the bone.
25 One more disadvantage of the electret implant which is the closest
analogue is the magnitude of the total electrostatic charge on the wedgeshaped
end of the implant. This is due to the fact that the proximal end of the
implant is wedge-shaped, starting from a method of its application –
8
hammering into the bone. On the edge of the wedge-shaped end, having a
very small area, there is a proportionally small number of charges that
proportionally reduces its impact on the effectiveness of reparative processes.
Another disadvantage of the implant-closest analogue is a dimensional
limit for its placing in small-sized bones of arms and legs5 .
Also, implementation of the implant as the plate requires a large
wrenching force to remove it from the hole in the case when the implant
needs to be replaced.
Challenge arising from the prior art is a creation of a new treatment
10 method, preventing the violation of an electret coating integrity during the
implant placing into the bone.
SUMMARY OF THE INVENTION
The subject-matter of the invention is defined in claim 1. Preferred
15 embodiments of the invention are defined in the dependent claims.
The task in the present method for treatment of arthrosis is solved by
the fact that the electret implant placing into the bone is made during the
treatment course. The method is characterized by a preliminary performed
hole in the bone directed towards a zone of maximum lesion by pathological
20 process. The electret implant is placed with a gap into the prepared hole in
the bone so that it is as close as possible to the bone area affected by the
pathological process. To prevent a displacement of the implant from the
optimal position for treatment the hole in the bone the implant is set by a
fixation device. After fixing it in the hole the electret implant is left in the
25 patient's bone to the moment when a pain syndrome appears once again,
which is associated with the fact that the electret is discharged and no longer
has a stimulating effect on bone structures.
9
Because the hole directed to the area of maximum destruction by the
pathological process was preliminary made in the bone, the electret implant is
placed with a gap in this hole so that it is as close as possible to the bone area
affected by the pathological process. The electret coating surface of the
proximal end of the electret is not damaged, namely the proximal end has th5 e
maximum charge magnitude, and thus has the maximum therapeutic effect on
bone tissues. Thus, the implementation of the preliminary hole and the
implant placement into it with a gap contributes to the electret coating charge
conservation, allows conservation of the electrostatic charge magnitude and
10 stability, lengthening of the therapeutic action duration of the electrostatic
field on damaged bone tissues by the pathological process in comparison with
the closest analogue. In this analogue the wedge-shaped proximal end is
hammered into the bone, leading to the violation of the electret coating
integrity in the wedge-shaped end area, the rapid discharge of the electret
15 coating, and consequently, the reduction of the therapeutic action duration of
the electrostatic field on bone tissues.
Furthermore, in the inventive method we are able to accurately orient
the implant relative to bone tissue affected by the pathology, optimizing the
healing process and increasing its effectiveness in comparison with the
20 closest analogue. In it the direction of hammering of the wedge-shaped end
into the bone is selected primarily basing on the need of an accurate mutual
orientation of bone parts connected by the implant (osteosynthesis).
Furthermore, thanks to the fact that the implant is placed into the hole
in the bone with a gap it allows to remove the excess tension inside the bone,
25 get rid of additional decompression holes (as it occurs in the nearest methodanalogue,
wherein the implant is hammered into the bone), which makes the
inventive method easier and reduces traumatism of its effects on the bone.
10
When the electret coating discharges, the discharged implant is
removed from the bone and the new one is placed instead of the old one. The
new one is a charged implant which resumes its therapeutic effect on bone
tissues.
As a fixation device of the electret implant in the hole in the bone 5 e a
bushing can be used. It is placed in the hole in the bone coaxially to this hole.
Through the bushing the implant can be placed inside the hole in the bone
and removed therefrom.
The bushing can be placed in the hole in the bone aflush with the outer
10 surface of the bone.
The task of the inventive electret implant, arising from the prior art, is
to ensure implementation of the method for treatment of arthrosis.
Another object of the inventive electret implant is to increase the total
electrostatic charge at the proximal end of the implant.
15 Furthermore, the inventive electret implant solves the problem of the
hole diameter reduction required for placing the implant into the hole in the
bone with a gap.
In addition, the inventive electret implant solves another problem:
reduction of efforts for wrenching the implant and reduction of bone
20 traumatism in case of the implant replacement.
Problems are solved due to the fact that the inventive electret implant
includes an extended body with a proximal and a distal end. On surface of the
body a dielectric coating in an electret state is formed. The distinguishing
feature of this implant is that its body is implemented as a rod, at the
25 proximal end of which a frontal surface is formed, and a fixation device of
the implant in a hole in a bone can be made at the distal end.
Due to the fact that the implant is made in the form of a rod, and the
frontal surface is formed at the proximal end, there is an increase of the
11
coating surface area of the proximal end in comparison with the closest
analogue, in which the proximal end is wedge-shaped. Consequently, we
obtain the much larger total charge at the proximal end of the proposed
implant in comparison with the total charge at the wedge-shaped proximal
end of the closest analogue and we increase the total area of contact of th5 e
implant with the bone. Thus, the therapeutic effect of the inventive implant
on the zone affected by necrosis is significantly stronger than the effect of the
electret coating with the wedge-shaped proximal end of the closest analogue.
Accordingly, the therapeutic efficiency of the proposed implant is much
10 higher than that for the closest analogue.
A spherical radius of the frontal surface edge of the implant proximal
end can preferably be in the range from 0.1 mm to 3 mm.
The rod may be made of metal.
The rod may also be made of non-metal. Wherein an electrically
15 conductive layer between the rod and the dielectric coating needs to be
formed. It allows the charging possibility of the dielectric coating.
As the insulating coating of the rod polytetrafluoroethylene, and (or) its
copolymers, and any other polymers and its compositions, which are
dielectrics and have electret properties, may be used.
20 As the insulating coating of the rod tantalum pentoxide or other oxides
of valve metals can be used.
The rod may have circular section in a plane perpendicular to its axis.
For the manufacturing of the rod also other cross-sectional shapes close to a
circular cross-section can be used.
25 The device for the implant fixation in the hole in the bone can be
formed by the fact that the distal end of the rod is bent at an angle to the rod
axis, and therein a reach-through hole for a screw for bonding to the bone is
made.
12
The device for the implant fixation can be formed by the fact that a
head with a conical outer surface for bonding with the bone is formed at the
distal end, and at least one screwdriver slot is made on the frontal surface of
the head.
The device for the implant fixation can be formed by the fact that th5 e
head with a thread on its lateral surface is formed at the distal end of the rod,
and at least one screwdriver slot is made on the frontal surface of the head.
The device for the implant fixation can be formed by the fact that the
distal end of the rod is pointed and is bent twice at right angle so that pointed
10 distal end is directed in parallel with the axis of the rod toward the proximal
end.
The reach-through hole to extract the rod from the hole in the bone,
when replacing the discharged electret implant by the new one with the
charged dielectric coating, can be formed at the distal end of the rod.
15 The device for the implant fixation can be formed as a cylindrical
bushing, and on its outer surface a thread for its set in the hole in the bone is
made, and on its inner surface a thread for fixation of the electret implant in
the hole is made. At least one screwdriver slot is made on the frontal surface
of the bushing. The bushing also provides for placing and removal of the
20 implant in the hole in the bone.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of an electret implant placed in a hole in a bone
and fixed in the bone by a screw (see claim 12).
25 FIG. 2 is a top view of an electret implant placed in a hole in a bone
and fixed in the bone by a screw (see claim 12).
13
FIG. 3 is a side view of an electret implant with a bent distal end
placed in a hole in a bone and fixed in the bone by a pointed distal end (see
claim 15).
FIG. 4 is a side view of an electret placed in a hole in a bone and fixed
by a head with a conical outer surface for bonding with the bone (see clai5 m
13)
FIG. 5 is a side view of an electret placed in a hole in a bone and fixed
by a thread formed on a cylindrical head of a rod (see claim 14).
FIG. 6 is a side view of an electret implant placed in a hole in a bone
10 through a bushing and fixed by a cap (see claim 18).
FIG. 7 is a top view of an electret implant placed in a hole in a bone
through a bushing and fixed by a cap (see claim 18).
FIG. 8 shows a 90-degree displacement of the electret implant of FIG.
7 with a hole for removal it from the bone.
15 FIG. 9 is a top view of an electret implant placed in a hole in a bone
through a bushing and fixed by a thread formed on a cylindrical head of a rod
wrapped inside the bushing (see claim 17).
DESCRIPTION OF PREFERRED EMBODIMENTS
20 Let’s consider the embodiment of the inventive method by the example
of treatment of dysplastic coxarthrosis of the left femoral head.
Patient K. (born in 1954) was admitted to the traumatology and
orthopedics clinic of the Kirov Military Medical Academy on occasion of the
above-mentioned diagnosis on 08.04.1996 (case history № 8276). The patient
25 was treated according to the inventive method: during the surgery under the
local anesthesia a cylindrical hole 2 with a diameter of 4.2 mm was made in
the patient’s bone 1 (FIG. 1, FIG. 2). An electret implant in the form of a
cylindrical rod 3 with a diameter of 4 mm was placed in the hole 2. The rod 3
14
had a rounded proximal end 4 and a distal end 5 bent at an angle to the axis of
the rod 3. At the proximal end 4 of the rod 3 a frontal surface is formed with
rounded edge. At the bent end 5 a reach-through hole 6 was made. Through
that hole 6 a screw 7 was twisted into the bone 1 for fixation of the rod 3
relative to the bone 1. The rod 3 is made of tantalum. On its surface 5 e a
dielectric coating 8 of tantalum pentoxide with a thickness of 0.3 microns
was formed by anodic oxidation. That coating had a distribution of the
electret potential with a maximum value at the proximal end 4 along the axis
of the rod 3. The electret coating 8, being inside the bone 1 for a long time (5
10 years or more), had the therapeutic (restorative) effect on bone tissue 1,
vessels, nerves and ligaments, etc., restoring the normal functioning of the
joint. Two days after the introduction of the electret implant into the femoral
head the pain stopped. Seven days later the patient was discharged from the
hospital. After 7 years the patient underwent the repeated surgery to replace
15 the implant 3 with the discharged electret coating 8 by the new implant 3
with the charged dielectric coating 8 in the 3rd city hospital of Saint-
Petersburg (case history № 22056). From 1996 to 2007 the bone tissue
structure reconstruction of femoral head was marked, the patient completely
refused medicaments, sanatorium-and-spa treatment was provided annually.
20 A contact is maintained with the patient K. Until 2014 the pain in hip joints
has not been renewed. Thus, the electret implant use has allowed avoiding
total joint replacement.
Due to the fact that the implant is made in the form of a rod 3, and the
frontal surface is formed at the proximal end 4, there is an increase of the
25 coating surface area 8 of the proximal end 4 in comparison with the closest
analogue, in which the proximal end is wedge-shaped. Consequently, we
obtain the much larger total charge at the proximal end 4 of the proposed
implant 3 in comparison with the total charge at the wedge-shaped proximal
15
end of the closest analogue and we increase the total area of contact of the
implant 3 with the bone 1. Thus, the therapeutic effect of the inventive
implant 3 on the zone affected by necrosis is significantly stronger than the
effect of the electret coating 8 with the wedge-shaped proximal end of the
closest analogue. Accordingly, the therapeutic efficiency of the implant 3 i5 s
significantly higher than that for the closest analogue.
Because the implant 3 is placed into the hole 2 with a gap, the surface
of the dielectric coating 8 is not damaged and it contributes to the charge
conservation of the electret coating 8, increasing the coating area, acting on
10 the affected bone structure, and lengthening (more than 5 years) the
therapeutic action duration of the electrostatic field on damaged bone tissues
by the pathological process in comparison with the closest analogue. In this
analogue the wedge-shaped proximal end is hammered into the bone, leading
to the violation of the electret coating integrity in the wedge-shaped end area,
15 the electrostatic charge loss, the rapid discharge of the electret coating, and
consequently, the reduction of the therapeutic action duration of the
electrostatic field on bone tissues.
The above-described inventive treatment method is one of the possible
embodiments of the proposed method of treatment and uses one of the
20 possible embodiments of the implant 3 and one of the possible embodiments
of the fixation device of the implant 3 in the hole 2.
The implant 3 may be placed in the hole 2 (see FIG. 3) and fixed in the
bone 1 by a pointed distal end 5. Thus the electret coating 8 of a proximal end
4 does not contact with the bone 1 during the placing process and its integrity
25 is not damaged.
The implant 3 may also be placed into the hole 2 (see FIG. 4) and fixed
tightly in the bone 1 by a head 9 with a conical outer surface 10. On the
frontal surface of the head 9 a screwdriver slot 12 is made.
16
The implant 3 may also be placed into the hole 2 (see FIG. 5) and fixed
into the bone 1 by a cylindrical head 12, on the lateral surface of which a
thread 13 is made. The implant 3 is twisted into the bone 1 by a screwdriver
inserted into a slot 14. The implant 3 is removed from the bone 1 by
unscrewing it from the bone 15 .
The implant 3 may also be placed into the hole 2 and fixed into the
bone 1 by a cylindrical bushing 15 (see FIG. 6, 7, 8) screwed into the bone 1
by a screwdriver coaxially to the hole 2 and inserted into a slot 16.
A screw cap 17 is used to fix the implant 3 into the hole 2. The screw
10 cap is twisted into the bushing 15 by a screwdriver slot 18, closing the hole 2
in which the implant 3 is placed. To remove the waste (discharged) implant 3
the screw cap 17 is untwisted, the implant 3 is picked up for a hole 19 and is
removed from the hole 2 in the bone 1. After that the charged implant 3 is
placed into the hole 2 through the bushing 15. Then the implant 3 is fixed
15 into the hole 2 by the screw cap 17 screwed into the bushing 15.
The implant 3 may also be placed and fixed into the hole 2 due to the
fact that the implant 3 is screwed into the bushing 15 using a cylindrical head
20 (FIG. 9) which is screwed into the bushing 15 by a screwdriver through a
slot 21.
Example № 2. Patient of 58 years old was admitted to the 3rd 20 city
hospital of Saint-Petersburg with the diagnosis: inveterate damage of internal
meniscus of anterior cruciate ligament and deforming arthrosis of the right
knee. Medical diagnostic arthroscopy and meniscectomy were performed; the
electret implant 3 was placed into the epiphysis of the tibia 1 on 27.11.2009.
25 Control radiography in the postoperative period (after 6, 12 and 24 months)
showed no progression of the degenerative process in condyles of the tibia
and the femur 1. The pain syndrome was arrested, the patient refused the
course of analgesic drugs.
17
Example № 3. . Patient N. of 18 years old was admitted to the 3rd city
hospital of Saint-Petersburg with the diagnosis of polyarthritis of unknown
etiology. She was able to move only in a wheelchair. In April 1990, she
underwent the surgery for the introduction of 3 tantalic electret implants in
the hip and the knee joints. As a result a few days after the surgery the pain 5 in
joints stopped. After 7 days the patient was already able to move on her own
feet. 12 days later she left the hospital and returned to normal life.
Example № 4. In May 1991 the patient N. of 60 years old was admitted
to the 3rd city hospital of Saint-Petersburg. The patient was exposed to
10 harmful and toxic chemicals in his workplace. As a result his femoral heads
began to disperse on the background of the lesion of blood and other
structural and functional disorders in the body that were not allowed to use
endoprosthesis replacement. The patient was bedridden. The surgery was
carried out for the introduction of tantalum implants 3 into the affected joint
15 bones 1. A week after the surgery the partial restoration of the joint function
was fixed. Three weeks later, the patient began to walk. Of course, at first he
walked with difficulty.
INDUSTRIAL APPLICABILITY
20 The inventive method was widely clinically tested in the Kirov
Military Medical Academy, the 3rd city hospital of Saint-Petersburg, and
children’s orthopedic sanatorium of the USSR Ministry of Defense in
Yevpatoria and showed a high efficiency.
More than 100 patients were operated and the disease was stopped in
25 97% of cases. It is not simply the removal of pain; it prevents the further
development of the disease.
18
The total cost of the disease treatment is reduced by more than 10
times in comparison with endoprosthesis replacement. The need of
postoperative rehabilitation is also eliminated.
19

CLAIMS:
1. An electret implant (3), comprising:
 an extended body having a proximal end (4) and a distal end (5);
 a dielectric coating (8) in an electret state being formed on th5 e
proximal end (4) of a surface of said body,
 a device (9, 12, 15) for the implant fixation in a bone (1),
wherein said body of said implant (3) is made in the form of a rod, at
the proximal end (4) of which a frontal surface is formed,
10 characterized in that the device (9, 12, 15) for the implant fixation is
made at the distal end (5) of said body and is adapted to fixation of the
implant (3) in a hole (2) in said bone (1), wherein the implant (3) is
adapted to be removably placed with a gap into the hole (2) in said
bone (1).
15
2. The electret implant of claim 1, wherein a spherical radius of an edge
of said frontal surface of said proximal end (4) is in the range from 0.1
mm to 3 mm.
20 3. The electret implant of claim 1, wherein said rod is made of metal.
4. The electret implant of claim 1, wherein said rod is made of non-metal,
and wherein an electrically conductive layer is formed between the rod
and the dielectric coating (8).
25
5. The electret implant of claim 1, wherein polytetrafluoroethylene and/or
its copolymers or all other polymers and its compositions with
dielectric properties are used as the dielectric coating (8) of said rod.
20
6. The electret implant of claim 1, wherein tantalum pentoxide or oxides
of other valve metals with electret properties are used as said dielectric
coating (8) of said rod.
7. The electret implant of claim 1, wherein said rod has a circular cross5 -
section in a plane perpendicular to its axis.
8. The electret implant of claim 1, wherein the device for the implant
fixation is formed by a bent distal end (5) of said rod at an angle to the
10 axis of said rod, wherein a reach-through hole (6) is provided at the
bent distal end (5) for a screw (7) for bonding to said bone (1).
9. The electret implant of claim 1, wherein the device for the implant
fixation is formed by a head (9) with a conical outer surface (10) for
15 bonding with said bone (1) at said distal end (5), wherein at least one
screwdriver slot (12) is provided on a frontal surface of said head (9).
10. The electret implant of claim 1, wherein the device for the implant
fixation is formed by a cylindrical head (12) with a thread (13) on its
20 lateral surface, wherein at least one screwdriver slot (14) is provided
on the frontal surface of said cylindrical head (12).
11. The electret implant of claim 1, wherein the device for the implant
fixation is formed by said distal end (5) of said rod being pointed and
25 bent twice at right angle so that this pointed distal end (5) is directed in
parallel with an axis of said rod toward said proximal end (4).
21
12. The electret implant of claim 1, wherein a reach-through hole (19) is
provided at said distal end (5) of said rod to extract said rod from the
hole (2) in said bone (1) when replacing the discharged electret implant
(3) by the new one with the charged dielectric coating (8).
5
13. The electret implant according to claim 1, wherein the device for the
implant fixation is a bushing, wherein on its outer surface a thread for
its set is made in said hole in said bone, and on its inner surface a
thread for fixation of the electret implant in said hole is made, and
10 wherein at least one screwdriver slot is made on a frontal surface of
said bushing to set the bushing in said hole in said bone.
14. The electret implant according to claim 13, wherein the bushing has a
screw cap to screw it inside the bushing for fixation of the electret
15 implant in said hole in said bone, and wherein at least one screwdriver
slot is made on the frontal surface of said screw cap.