JP2016150216A - Trocar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trocar capable of ensuring a large visual field.SOLUTION: A trocar 1 including a pipe part 2 causing a medical instrument to be inserted into a body, the pipe part including a pipe outer cylinder 21 and a pipe inner cylinder 22, the pipe outer cylinder including a side face opening at a position inserted into a body. A storage type camera 6 is arranged, the storage type camera capable of being switched through the side face opening between a storage position stored in the pipe part and an expansion position expanded outside the pipe part for enabling photographing. A space for inserting through a cable 7 connected to the storage type camera is formed between the pipe outer cylinder and the pipe inner cylinder.SELECTED DRAWING: Figure 2

Description

  The present invention is a patent application subject to the application of the Ministry of Economy, Trade and Industry's “Medical and Industrial Cooperation Promotion Project Demonstration Project” commissioned research, Article 19 of the Industrial Technology Strengthening Act, which is used for endoscopic surgery. Related to trocars.

  In recent years, there has been a demand for minimally invasive surgery such as laparoscopic surgery in which an endoscope is inserted into the abdominal cavity in order to maintain and improve the quality of life (QOL) of patients. Laparoscopic surgery involves injecting carbon dioxide into the abdominal cavity to inflate the abdominal wall to ensure space and field of view for the procedure. Then, a small hole is made in the abdominal wall, an instrument called a trocar is inserted, an endoscope (CCD camera, etc.) and forceps that are surgical instruments are inserted into the patient's body, and the image displayed on the monitor by the endoscope It is common to perform surgery while observing (Patent Documents 1 and 2).

  In such a conventional endoscopic surgical operation, since usually one endoscope is inserted, the visual field is limited, and there is very little information that an operator can judge by looking at the monitor during the procedure. On the other hand, it is possible to secure a wider field of view by additionally inserting an endoscope, but it is necessary to make a new hole in the body wall to insert the endoscope, which increases the burden on the patient. End up. In view of this, a proposal has been made to expand the observation field of view in laparoscopic surgery by attaching a small camera to a trocar used in laparoscopic surgery (Patent Document 3).

  When a camera is attached to such a trocar, when the trocar is inserted into the abdominal cavity, the camera is stored in the main body at the time of insertion, and the distal end portion in which the trocar camera is stored is inserted into the abdominal cavity. At the time, a mechanism for operating the camera from the trocar body outside the abdominal cavity is employed.

JP 2013-046789 A JP 2006-167475 A JP 2014-132799 A

  It is an object of the present invention to provide a trocar with superior operability with respect to a trocar with a camera that can ensure a wide field of view.

An embodiment of the present invention for solving the above problems has the following configuration.
(1) A trocar having a pipe part for inserting a medical instrument into the body, wherein the pipe part includes a pipe part outer cylinder and a pipe part inner cylinder, and the pipe part outer cylinder is inserted into the body. A retractable camera that has a side opening at a position, and is capable of switching between a storage position stored in the pipe section and a deployment position deployed so as to be photographed outside the pipe section through the side opening. The trocar is characterized in that a space through which a cable connected to the retractable camera is inserted is formed between the pipe portion outer cylinder and the pipe portion inner cylinder.
(2) The trocar according to (1), wherein an inner surface of the pipe portion outer cylinder has a circular cross section, and the pipe portion inner cylinder has a D-shaped cross section for forming the space between the pipe portion outer cylinder and the pipe portion outer cylinder. .
(3) The storage position and the deployment position of the retractable camera are switched by pushing and pulling the pipe portion inner cylinder in the axial direction of the pipe portion with respect to the pipe portion outer cylinder (1) or The trocar according to (2).
(4) The cable is a flexible signal / power cable, and is inserted into the space with a sufficient length so that the cable is not pulled when the retractable camera unit is switched between the retracted position and the deployed position. The trocar according to any one of (1) to (3).
(5) The trocar according to any one of (1) to (4), wherein the medical instrument is inserted into the body through the pipe portion inner cylinder.
(6) A stepped region having a plurality of step portions arranged in parallel in the axial direction of the pipe portion is formed on the outer peripheral surface of the pipe portion outer tube, and each step portion has a radius of the pipe portion outer tube. A rising surface rising outward in the direction, and a tapered surface having a downward slope from the apex of the rising surface toward the base of an adjacent step portion located on the distal end side of the pipe portion outer cylinder ( The trocar according to any one of 1) to (5).
(7) The trocar according to (6), wherein the pipe portion outer cylinder includes the stepped region and a region without the step portion along a circumferential direction.
(8) The trocar according to (7), wherein each step portion in the stepped region has a height that does not protrude from a surface of the region without the step portion.
(9) The trocar according to (7) or (8), wherein the region without the stepped portion includes a thin portion region of the pipe portion outer cylinder.
(10) The camera is stored in the pipe with pressure applied when the trocar is pulled out from the body cavity in a state in which the retractable camera is deployed outside the pipe. ) The trocar according to any one of
(11) The retractable camera includes a camera unit and an illumination unit inside, and has a translucent cover on the front surface of the trocar in the body insertion direction. Trocar as described in.
(12) A cleaning means that contacts the front surface of the translucent cover when the retractable camera is switched between the retracted position and the deployed position is provided in the side opening of the pipe portion outer cylinder (1). The trocar according to any one of to (11).
(13) A cleaning means that comes into contact with the lens front surface of the retractable camera when the retractable camera is switched between the retracted position and the unfolded position is provided in the side opening of the pipe portion outer cylinder (1). -The trocar in any one of (10).

According to the present invention, after the trocar is inserted into the body cavity, the retractable camera can be deployed to the outside of the pipe from the side opening provided on the outer pipe of the pipe so that the field of view during surgery is widened. effective.
In addition, since the pipe portion inner cylinder has the original function of inserting the medical instrument into the body and the retractable camera is provided in the pipe portion outer cylinder, the trocar can be downsized.

1 is a perspective view showing a trocar with a retractable camera deployed according to an embodiment of the present invention. FIG. (a), (b) is sectional drawing which shows the expansion | deployment state and retracted state of the retractable camera in the trocar shown in FIG. 1, respectively. It is a fractured perspective view in the deployment state of a retractable camera. It is a perspective view which shows a retractable camera. (a)-(c) is sectional drawing which shows operation | movement from the expansion | deployment state of a retractable camera to a retracted state. (a)-(c) is explanatory drawing which shows operation | movement from the expansion | deployment state of a retractable camera to a storage state. It is a fracture perspective view which shows the space for cable insertion in a trocar. (a) is a cutaway perspective view showing a stepped region formed on the outer peripheral surface of the pipe portion outer cylinder of the trocar, (b) is a perspective view showing a boundary portion between the stepped region and the region without the stepped portion, (c) ) Is an enlarged cross-sectional view showing a stepped portion. It is a fractured perspective view showing a pipe part outer cylinder of a trocar. (a), (b) is the XX sectional view taken on the line of FIG. 9, and the YY sectional view, respectively. (a) is the fragmentary perspective view which shows the unfolded state of a retractable camera, (b) is the expansion fracture perspective view.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a trocar 1 according to an embodiment of the present invention. The trocar 1 is used in, for example, laparoscopic surgery, and includes a pipe portion 2 on the distal end side (distant position) when viewed in the direction of insertion at the time of surgery and an operator side (hereinafter referred to as “front side”). And the head portion 3 at the position of the case. Most of the pipe portion 2 is inserted into a hole in the abdominal wall. The head part 3 is provided continuously with the pipe part 2. The head portion 3 is hollow, and forceps and the like (not shown) can be inserted from an opening formed on the front side thereof.

  The trocar 1 has a double structure of the pipe portion 2 and the head portion 3 as shown in FIGS. 2A and 2B in order to operate a camera mechanism described later. That is, the pipe part 2 is constituted by a pipe part outer cylinder 21 and a pipe part inner cylinder 22, and the head part 3 is constituted by a head part outer cylinder 21a and a head part inner cylinder 22a. The pipe part outer cylinder 21 and the head part outer cylinder 21a, and the pipe part inner cylinder 22 and the head part inner cylinder 22a are formed integrally, or are connected or connected together.

  Further, as shown in FIGS. 2A and 2B, the head inner cylinder 22a is used as a sealing mechanism for preventing gas leakage when inserting and removing forceps or the like in the head inner cylinder 22a continuous to the pipe inner cylinder 22. A duckbill valve 27 is incorporated on the tip side (distant position) of the dome, and a dome-shaped valve 28 is incorporated on the front side thereof. The head outer cylinder 21a that is continuous with the pipe outer cylinder 21 is connected to an air supply pipe 4 that feeds a gas such as carbon dioxide or air into the abdominal cavity and a signal / power cable extending from the retractable camera 6. The connector part 5 is provided. The gas sent from the air supply pipe 4 attached to the head part outer cylinder 21a is sent into the abdominal cavity from a space (a space 18 described later) formed between the pipe part outer cylinder 21 and the pipe part inner cylinder 22, The inside is pressurized. Here, the duckbill valve 27 is a valve mechanism for preventing leakage of gas pressurized into the abdominal cavity before insertion of a surgical instrument such as forceps, and the dome-shaped valve 28 is a surgical instrument such as forceps. When the is inserted, the surgical tool is allowed to move and is in close contact with the surgical tool to prevent leakage of pressurized gas in the abdominal cavity that cannot be sealed with the duckbill valve 27.

Further, the pipe unit 2 is provided with a retractable camera 6 (hereinafter sometimes simply referred to as the camera 6) for imaging the insertion direction into the abdominal cavity. As will be described later, the camera 6 can be stored in the pipe portion 2 and is deployed outward from the outer peripheral surface of the pipe portion 2 as shown in FIG.
2A and 2B are cross-sectional views showing the unfolded state and retracted state of the retractable camera 6 in the trocar 1 shown in FIG. As shown in the figure, the pipe part includes a pipe part outer cylinder 21 and a pipe part inner cylinder 22. Switching between the retracted position and retracted position of the retractable camera 6 is performed by pushing and pulling the pipe inner cylinder 22 in the axial direction of the pipe section 2 with respect to the pipe outer cylinder 21.

That is, as described later, when the head portion inner cylinder 22a of the head portion 3 is pushed in and the pipe portion inner cylinder 22 is pushed toward the tip of the pipe portion 2, the camera 6 is connected to the pipe as shown in FIG. When the head inner cylinder 22a is pulled out from the head outer cylinder 21a, the pipe inner cylinder 22 is pulled out and the camera 6 is retracted.
In this camera deployment and storage mechanism, a pin 37 is provided on the head portion 22a of the pipe portion inner cylinder 22 so that smooth operation is possible and the pipe portion inner tube 22 is not excessively moved with respect to the pipe portion outer cylinder 21. A slit 38 is formed in the head portion 21 a of the tube 21 at a position corresponding to the pin 37 along the axial direction of the pipe portion 2. The movement of the pin 37 is regulated by the slit 38.

As shown in FIG. 3, the camera 6 is provided with a camera lens 8 on the front surface and provided with illumination units 9 such as LEDs on both sides thereof. Further, the camera 6 is deployed outward through a side opening 10 formed in the pipe outer cylinder 21. Further, on both sides of the bottom of the camera 6, skirt portions 11 are provided that extend toward the side of the camera 6 along the inner peripheral surface of the pipe outer cylinder 21 when the camera 6 is deployed or stored.
FIG. 4 is a perspective view of the camera 6 observed from the back side, and a protrusion 12 is provided on the outer surface of the skirt 11. Further, a cam mechanism 29 is connected to the far position (tip side) of the pipe portion inner cylinder 22 (see FIG. 3), and the cam mechanism 29 has a plate-like form in which the inclined groove 13 is formed. The protrusion 12 engages with the inclined groove 13 of the cam mechanism 29 and the vertical groove 14 formed on the inner peripheral surface of the pipe portion outer cylinder 21 in this order as shown in FIG. It slides along these grooves 13 and 14 at the time of storing. Due to such a configuration, when the camera 6 is attached to the trocar 1, the camera 6 can be incorporated from the inside of the trocar 1, and the camera 6 may be accidentally dropped from the pipe outer cylinder 21 during the operation. Can be prevented.

The deployment / storage mechanism of the camera 6 will be described below. As shown in FIG. 3, in the storage part 61 of the camera 6, the inner surface of the pipe part outer cylinder 21 has a rectangular cross section so as to form a slide type cam mechanism 29, and the tip part of the pipe part inner cylinder 22 is also The storage portion 61 has a rectangular cross section and is slidably inserted into the pipe portion outer cylinder 21.
The pipe inner cylinder 22 is formed with an inclined groove 13 at the front end of a rectangular cross section, and further, an inclined step portion 15 having the same inclination angle as the inclined groove 13 is formed at the rear (front side) thereof. On the other hand, the rear end portion 16 of the skirt portion 11 of the camera 6 shown in FIG. 4 has an inclined surface corresponding to the inclined step portion 15. Then, as shown in FIG. 5, the rear end portion 16 of the inclined skirt portion 11 is placed on the inclined step portion 15 of the pipe portion inner cylinder 22.

As shown in FIG. 5A, when the camera 6 is unfolded, the rear end portion 16 of the skirt portion 11 is positioned above the inclined step portion 15 of the pipe portion inner cylinder 22, and is shown in FIG. As described above, the protrusion 12 of the skirt 11 is located above the inclined groove 13 and the vertical groove 14. From this state, when the pipe portion inner cylinder 22 is pulled rearward (front side), as shown in FIGS. 5B and 5C, the rear end 16 of the skirt portion 11 is connected to the pipe. As shown in FIGS. 6B and 6C, the protrusion 12 of the skirt portion 11 has the inclined groove 13 of the pipe inner tube 22 rearward. It moves down along the longitudinal groove 14 in conjunction with the movement. As a result, the camera 6 can be lowered and stored through the side opening 10 of the pipe outer cylinder 21.
On the other hand, when unfolding the camera 6, the reverse operation is performed.

As shown in FIGS. 5 and 6, the front end of the lid portion 17 is attached to the front side (head portion 3 side) of the camera 6 so as to be rotatable by, for example, a hinge portion 30. Further, the rear end (front side) of the lid body portion 17 is rotatably attached to the pipe portion outer cylinder 21 by a hinge portion 31. For this reason, the lid portion 17 follows the unfolding / storage of the camera 6 and can close the side opening 10 together with the upper surface of the camera 6 when the camera 6 is stored.
As the hinge part 30, the rotation axis | shaft which connects the camera 6 and the cover body part 17 so that rotation is possible is mentioned, for example. Similarly, for example, the hinge part 31 is a rotation shaft that rotatably connects the lid part 17 and the pipe part outer cylinder 21. It is desirable that the hinge portions 30 and 31 have a structure that prevents adhesion of body fluid or the like during the operation by covering them with a flexible seal member.

  The lid 17 has an inclined posture when the camera 6 is deployed. Therefore, for example, even when an emergency occurs during the operation and the trocar 1 needs to be pulled out, the pressure applied to the lid portion 17 when the trocar is pulled out from the body cavity, instead of being pulled out after storing the camera 6. Thus, the camera 6 can be stored in the pipe portion 2.

(Space 18 and cable layout)
As described above, the camera 6 includes the camera unit including the imaging element and the lens 8 and the illumination unit 9 therein. As shown in FIGS. 5A to 5C, the cable 7 for energizing these devices and transmitting / receiving electronic signals has a space 18 between the pipe portion outer cylinder 21 and the pipe portion inner cylinder 22. As shown, the bottom of the lid 17 is drawn into the camera 6 from the rear of the camera 6.

FIG. 7 shows a cross-sectional shape of the pipe portion 2 between the storage portion 61 of the camera 6 and the head portion 3 provided on the front side of the trocar 1. As shown in the figure, the pipe outer cylinder 21 has a circular cross section on the inner surface, and the pipe inner cylinder 22 has a D-shaped cross section. As a result, a space 18 for inserting the cable 7 can be formed between the pipe portion outer cylinder 21 and the pipe portion inner cylinder 22.
The present invention is not limited to the combination of the pipe section outer cylinder 21 having a circular cross section and the pipe section inner cylinder 22 having a D section, and a space 18 for inserting the cable 7 can be secured, and the pipe section Any shape may be used as long as the outer cylinder 21 can be rotated.

(Cable 7 placement (routing))
The cable 7 is a flexible signal / power cable, and is inserted into the space 18 with a sufficient length so that the cable 7 is not pulled when the retractable camera unit is switched between the retracted position and the unfolded position. (Refer to Drawing 5 (a)-(c)).
Specifically, as shown in FIGS. 5A to 5C, the cable 7 connected to the connector portion 33 disposed in the space 32 in the camera 6 is formed on the near side of the space 32. It is drawn to the near side from the slit 34 and led to the space 18 along the inner side 34 of the lid portion 17 so as to draw a loose arc.

(Space 18 as an air supply gas flow path)
As described above, the space 18 is a space for arranging the cable 7 so as not to generate a large load when the camera unit is deployed and stored. In addition to this function, the space 18 also functions as a flow path for supplying gas to the body cavity. ing. Specifically, as shown in FIGS. 2 (a) and 2 (b), the gas (such as carbon dioxide) supplied from the air supply pipe 4 provided in the head portion outer cylinder 21a is separated from the head portion outer cylinder 21a and the head. An opening formed at a remote position (tip) of the pipe outer cylinder 21 through the space 18 formed between the pipe outer cylinder 21 and the pipe inner cylinder 22 through the space between the inner cylinder 22a. 35 is supplied into the body cavity.

(Retaining structure)
As shown in FIG. 7, a stepped region 19 having a plurality of stepped portions 20 arranged in parallel in the axial direction of the pipe portion is formed on the outer peripheral surface of the pipe portion outer cylinder 21. As shown in FIG. 8C, each step portion 20 includes a rising surface 20 a that rises outward in the radial direction of the pipe portion outer cylinder 21, and an apex 20 c of the rising surface 20 a, and the tip of the pipe portion outer cylinder 21. And a tapered surface 20b having a downward slope toward the base portion 20c of the adjacent step portion 20 located on the side.
Since each step portion 20 has a rising surface 20a facing the head portion 3, the trocar 1 is not prepared due to the pressure of gas injected into the abdominal cavity when the trocar 1 is placed and held on the abdominal wall. Can be prevented from falling out. Further, since each step portion 20 is formed with a tapered surface 20b, insertion of the trocar 1 into the abdominal cavity is not hindered. When the trocar 1 is pulled out, for example, the trocar 1 may be pulled out while rotating.

  As shown in FIG. 7, the stepped regions 19 are alternately formed with regions (stepped regions) 23 having no step portions along the circumferential direction. The reason is that, when the pipe part outer cylinder 21 is manufactured by resin molding, the direction in which the molded pipe part outer cylinder 21 is pulled out of the mold is the direction indicated by the arrow in FIG. become. At that time, as shown in FIG. 10 (a), as shown in FIG. 10 (b), as shown in FIG. This is because, since the thin portion 24 is formed in the circular cross section, if the stepped region 19 is formed over the entire circumference of the pipe portion outer cylinder 21, the thin portion 24 may reduce the strength.

  From such a point of view, in FIG. 7, three stepped regions 19 are formed alternately and evenly in the circumferential direction with regions (stepped regions) 23 having no stepped portions. By providing such a non-stepped region 23, the trocar 1 can be pulled out without any trouble. On the other hand, if the thickness of the pipe part outer cylinder 21 is ensured, the stepped region 19 may be formed over the entire circumference of the pipe part outer cylinder 21, or only one or two parts may be formed. You may form in more than a location (for example, 10 locations).

  In addition, each step 20 in the stepped region 19 has a height that does not protrude from the surface of the non-stepped region 23. For example, when the trocar 1 is pulled out while rotating, the step 20 does not get in the way. preferable.

(Camera and lighting)
FIG. 11 shows the distal end portion of the pipe portion outer cylinder 21 in a state where the camera 6 is unfolded. As described above, the camera 6 includes the camera unit having the lens 8 inside and the illumination unit 9, and a transparent glass plate or a transparent resin plate is provided in the photographing window 36 located in front of the trocar 1 in the insertion direction of the body. A translucent cover 25 made of, for example, is fixed by means such as adhesion, and photographing and illumination are performed through the translucent cover 25.

(Cleaning means)
A cleaning means 26 that contacts the front surface of the translucent cover 25 is attached to the front surface of the side surface opening 10 of the pipe outer cylinder 21 (the distal end side (distant position) of the trocar 1). Thereby, when the camera 6 is switched between the storage position and the unfolded position, dirt and fogging on the front surface of the translucent cover 25 can be wiped off by the cleaning means 26. For this reason, when body fluid or the like adheres to the translucent cover 25 or becomes clouded with water vapor and the field of view deteriorates, the camera 6 is switched between the storage position and the deployment position as described above. , Can restore good visibility. Accordingly, when the visibility is deteriorated as in the prior art, it is not necessary to remove the dirt by removing the trocar 1 from the body and immersing it in hot water, thereby enabling quick laparoscopic surgery. .

  The cleaning means 26 may be, for example, a warper blade made of rubber or resin, but is not limited thereto, and may be a brush, sponge (soft foam), laminated cloth, pile fabric, or the like.

  Next, the airtight structure adopted in the pipe portion outer cylinder 21 of the trocar 1 having the function of deploying and storing the camera 6 will be described. As shown in FIG. 11B, in the camera 6, the translucent cover 25 provided on the photographing window 36 is sealed with, for example, a silicon-based adhesive, while the front cable shown in FIG. The slit 34 for pulling out 7 is sealed with a rubber adhesive. Thus, the camera 6 has an airtight waterproof structure as a whole.

Further, in order to suppress intrusion of body fluid or the like from the side opening 10 formed in the pipe outer cylinder 21 into the pipe 2 and to suppress gas leakage, the entire circumference of the side opening 10 is provided. The skirt portions 11 provided on both sides of the bottom portion of the camera 6 are shaped so as to extend more laterally than the camera 6 along the inner peripheral surface of the pipe portion outer cylinder 21. Therefore, the skirt portion 11 is configured to be in close contact with and slidably contact the inner surface of the pipe portion inner cylinder 22. Preferably, a sealing material is interposed between the skirt portion 11 and the pipe portion inner cylinder 22.
Further, the lid 17 closes the side opening 10 together with the upper surface of the camera 6 when the camera 6 is stored, and also ensures airtight waterproofing by the seal provided on the side opening 10 even when the camera 6 is deployed. can do. Even when the camera 6 is unfolded, this seal is interposed between the lid portion 17 and the side surface opening 10 to ensure the internal airtightness.

  On the other hand, in order to prevent gas leakage from the head portion 3 at the front side position, in addition to the duckbill valve 27 and the dome-shaped valve 28, the space side entrance of the connector portion 5 is as shown in FIG. A first sealing member 39 such as rubber inserted through the cable 7 is fitted, and on the other hand, on the front side of the slit 38 and on the front side of the air supply tube 4, a head is provided between the pipe outer cylinder 21 and the inner cylinder 22. A second sealing material 40 such as rubber is provided over the entire circumference of the portion 3. The second sealing member 40 is attached to either the pipe portion outer cylinder 21 or the inner cylinder 22 by adhesion or the like.

  Since the cable 7 is not exposed to the outside due to the above structure, there is no possibility of problems such as cable deterioration due to water getting wet. Further, the gas (carbon dioxide gas or the like) supplied from the air supply pipe 4 is reliably supplied into the body cavity from the opening 35 of the pipe portion outer cylinder 21.

  Although the trocar 1 according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various improvements and improvements can be made. For example, when the translucent cover 25 is not used, the side opening of the pipe outer cylinder is arranged so that the cleaning means contacts the front surface of the lens of the retractable camera when the retractable camera is switched between the retracted position and the deployed position. You may provide in the part. The trocar of the present invention can also be suitably used for endoscopic surgery in the thoracic cavity.

DESCRIPTION OF SYMBOLS 1 Trocar 2 Pipe part 3 Head part 4 Air supply pipe 5 Connector part 6 Retractable camera 7 Cable 8 Lens 9 Illumination part 10 Side surface opening part 11 Skirt part 17 Cover part 18 Space 19 Stepped area 20 Step part 21 Pipe part outer cylinder 22 Pipe portion inner cylinder 23 Non-stepped region (region without stepped portion)
25 Translucent cover 26 Cleaning means

Claims (13)

A trocar having a pipe part for inserting a medical instrument into the body,
The pipe part includes a pipe part outer cylinder and a pipe part inner cylinder,
The pipe part outer cylinder has a side opening at a position where it is inserted into the body, and through this side opening, a storage position stored in the pipe part and a development that can be photographed outside the pipe part. There is a retractable camera that can switch between positions,
A trocar characterized in that a space through which a cable connected to the retractable camera is inserted is formed between the pipe part outer cylinder and the pipe part inner cylinder.   2. The trocar according to claim 1, wherein an inner surface of the pipe portion outer cylinder has a circular cross section, and the pipe portion inner cylinder has a D-shaped cross section for forming the space between the pipe portion outer cylinder and the pipe portion outer cylinder.   The switching between the retracted position and the unfolded position of the retractable camera is performed by pushing and pulling the pipe portion inner cylinder in the axial direction of the pipe portion with respect to the pipe portion outer cylinder. Trocar.   The cable is a flexible signal / power cable, and is inserted into the space with a sufficient length so that the cable is not pulled when the retractable camera unit is switched between a retracted position and a deployed position. Item 4. The trocar according to any one of Items 1 to 3.   The trocar according to any one of claims 1 to 4, wherein the medical instrument is inserted into the body through the pipe portion inner cylinder.   A stepped region having a plurality of step portions arranged in parallel in the axial direction of the pipe portion is formed on the outer peripheral surface of the pipe portion outer tube, and each step portion is directed outward in the radial direction of the pipe portion outer tube. And a tapered surface having a downward slope from the apex of the rising surface toward the base of an adjacent step located on the distal end side of the pipe portion outer cylinder. The trocar according to any one of 5.   The said pipe part outer cylinder is a trocar of Claim 6 which has the said stepped area | region and the area | region without the said step part along the circumferential direction.   The trocar according to claim 7, wherein each step portion in the stepped region has a height that does not protrude from a surface of the region without the step portion.   The trocar according to claim 7 or 8, wherein the region without the stepped portion includes a thin portion region of the pipe portion outer cylinder.   10. The camera according to claim 1, wherein the camera is stored in the pipe portion with pressure applied when the trocar is pulled out from a body cavity in a state where the retractable camera is deployed outside the pipe portion. The described trocar.   The trocar according to any one of claims 1 to 10, wherein the retractable camera includes a camera unit and an illuminating unit therein, and has a translucent cover on a front surface of the trocar in a body insertion direction.   The cleaning means that comes into contact with the front surface of the translucent cover at the time of switching between the retracted position and the unfolded position of the retractable camera is provided in the side opening of the pipe portion outer cylinder. The trocar according to any one. The cleaning means that contacts the lens front surface of the retractable camera when switching between the retracted position and the unfolded position of the retractable camera is provided in the side opening of the pipe portion outer cylinder. The trocar according to any one.