Surgical apparatus

A surgical apparatus comprises a rigid sheath, an object observation mechanism and an observation optical axis rotating mechanism. The sheath has a distal opening and a proximal opening. The object observation mechanism is inserted into the sheath from the proximal opening. The observation optical axis rotating mechanism rotates the object observation mechanism about the axis of the sheath.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-285829, filed Sep. 19, 2001, the entire contents of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a surgical apparatus that can be inserted into an intracavital of a patient to thereby treat an affected area while observing the area using, for example, an endoscope.

2. Description of the Related Art

In recent surgical operations, a working space is secured by inserting a cylindrical sheath into an intracavital of a patient. The to-be-treated portion is observed by an endoscope inserted in the sheath. The to-be-treated portion or affected portion is treated by a surgical instrument inserted in a space between the endoscope and sheath. This technique is now widely used to reduce the invasiveness.

In the field of cerebral nerve surgery, endoscopic surgical operations using such a sheath have been recently demanded.

U.S. Pat. No. 6,142,931 has proposed, an example of an endoscopic surgical apparatus using a sheath. In this apparatus, an endoscope having an oblique-viewing angle of 30° or more with respect to the axis of its insertion section is provided in a sheath. The insertion section of the endoscope is arranged on the circumference of the sheath around the axis.

U.S. Pat. No. 5,697,939 discloses a holder apparatus. This apparatus fixes one point of the endoscope insertion section so that the insertion section can only rotate about the one point. This enables the field of view to be changed within an intracavital of a patient.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a surgical apparatus comprising:

a rigid sheath having a distal end having a distal opening, a circular proximal end having a proximal opening, and an axis;

an object observation mechanism having an observation optical axis inclined to the axis of the sheath, the object observation mechanism being inserted into the sheath; and

an observation optical axis rotating mechanism for rotating the object observation mechanism about the axis of the sheath.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the invention will be described with reference to the accompanying drawings.

Referring first toFIGS. 1to3, a first embodiment of the invention will be described.FIG. 1is a schematic view partly in section, illustrating the entire structure of an endoscopic surgical system50according to the first embodiment.

An endoscope16employed in the system50is a rigid-type endoscope. As seen fromFIG. 1, the endoscope16comprises an elongated insertion section21and eyepiece section (hand-side section)22located at the hand-side end of the insertion section21. It is preferable that the insertion section21and eyepiece portion22have respective circular cross sections. The insertion section21has an insertion axis Ob. It is preferable that the insertion section21and eyepiece portion22are coaxial. In other words, the insertion section21and eyepiece portion22preferably have the same axis Ob.

An object optical system30including an objective lens23and prism24is provided at the distal end of the insertion section21of the endoscope16. The observation optical axis Oo of the object optical system30is inclined at an angle θ with respect to the insertion axis Ob of the insertion section21. The observation optical axis Oo of the object optical system30is separate from the insertion axis Ob near the lower end of the prism24(i.e., at the objective lens23). On the contrary, from the patient3side, the observation optical axis Oo of the object optical system30coincides with the insertion axis Ob near the prism24.

A relay lens25for relaying the image entering the object optical system30is provided in the insertion section21. The eyepiece portion22has an eyepiece26for receiving the image transmitted through the relay lens25.

An interchangeable tip28having an imaging lens27is provided integrally with the upper end (proximal end) of the eyepiece portion22. A TV camera32containing a CCD31as an image pickup element is rotatably connected to the upper end of the interchangeable tip28, and arranged coaxially with the endoscope16.

Thus, the object optical system30, relay lens25, eyepiece26, imaging lens27and CCD31are arranged on the insertion axis Ob. The TV camera32is connected to a TV monitor34via a controller33having a video signal processing function.

The endoscope16also comprises an illumination optical system (not shown) for illuminating an affected area3, and a light guide (not shown) for guiding the light emitted from a light source (not shown), to the illumination optical system. An illumination light transmissions mechanism for guiding the light from the light source is connected to the light guide. Thus, light is guided from the light source to the illumination optical system via the illumination light transmission mechanism and light guide.

AS shown inFIGS. 2A and 2B, a connection portion43having a smaller diameter than the eyepiece portion22is formed in the vicinity of an end of the eyepiece section22. The outer diameter of the connection portion43is between the outer diameters of the insertion section21and eyepiece portion22of the endoscope16. It is preferable that the end surfaces (boundary portions; stepped portions)44of the insertion section21and eyepiece portion22with respect to the connection portion43are perpendicular to the insertion axis.

As shown inFIG. 1, the endoscopic surgical system50has a sheath1formed of a rigid hollow cylindrical member having a distal opening and proximal opening. The sheath1has an axis Oa that passes through the respective central points of the distal and proximal openings. The sheath1is inserted into an opening2formed in, for example, the head of a patient (object). The observation or treatment of the affected area3located at the bottom of the opening2in the head of the patient is executed through the sheath1. The sheath1is fixed to, for example, an operating table (not shown), by means of a holder arm10.

An outwardly projecting annular flange4is formed at the proximal opening (hand-side opening) of the sheath1. The axis of the flange4is identical to that of the sheath1, Oa. A cylindrical rotary ring (rotary cylinder)5is detachably attached to the flange4.

The rotary ring5has a ring portion6in contact with the upper end (hand-side end) of the flange4, and a cover portion7that project from the outer periphery of the ring portion6along the axis of the sheath1and covers the outer periphery of the flange4. A screw portion9ais formed at the inner peripheral surface of the edge of the cover portion7.

A fitting ring8is fitted on the side of the ring5opposing the ring portion6with the flange4interposed therebetween. A screw portion9bengaged with the aforementioned screw portion9ais formed at the outer periphery of the fitting ring8. When the screw portions9aand9bare engaged with each other, drop of the rotary ring5is prevented. As a result, the rotary ring5is kept in contact with the flange4.

In this state, the rotary ring5is in contact with the hand-side end of the flange4and is rotatable about the axis Oa of the sheath1. The hand-side end surface of the flange4is in contact with the inner surface of the ring portion6opposite its hand-side end surface such that the contact surfaces can smoothly slide relative to each other. Further, the surface of the flange4opposite its hand-side surface is in contact with the inner surface of the ring8such that the contact surfaces can smoothly slide relative to each other.

The cover portion7of the rotary ring5has a screw hole13formed therethrough from the outer periphery to the inner periphery, i.e., toward the axis Oa. A fastening screw15having a tab14is screwed into the screw hole13. When the tip of the fastening screw15is pressed against the outer periphery of the flange4, the rotation of the rotary ring5around the flange4is stopped. On the other hand, when the tip of the fastening screw15is separated from the outer periphery of the flange4, the rotary ring5can rotate around the flange4. Thus, an engagement mechanism for engaging and disengaging the rotary ring5with and from the flange4is realized.

A description will now be given of a rotary support mechanism40for supporting the endoscope16such that the endoscope can rotate about the axis Oa of the sheath1. As shown inFIGS. 1 and 3, the rotary support mechanism40comprises the aforementioned rotary ring5, a holding arm41projecting from the rotary ring5and formed integrally as one body with the inner periphery of the ring5, and a holding cylinder42formed at the distal end of the holding arm41. The upper surface of the holding cylinder42is parallel to the hand-side end surface of the sheath1. Further, the axis of the holding cylinder42is displaced by a distance (radius) R from the axis Oa of the sheath1. It is preferable that the position of the holding cylinder42along the axis of the sheath1can be varied in accordance with the focal point of the endoscope16. This can be realized by, for example, preparing a plurality of rotary support mechanisms40and exchanging one for another.

As shown inFIGS. 2A and 2B, the aforementioned connection portion43of the endoscope16is fitted in the holding cylinder42of the rotary support mechanism40. Accordingly, the endoscope16is held so that it can rotate about the insertion axis Ob. When the connection portion43is fitted in the holding cylinder42, the upper surface of the connection portion43is level with the upper end of the holding cylinder42.

As shown inFIGS. 2A and 2B, a slit46having a predetermined width is formed in the outer periphery of the connection portion43along the insertion axis Ob. For example, the slit46is positioned opposite the observation optical axis Oo with respect to the insertion axis Ob of the endoscope16(i.e., displaced by 180° from the axis Oo). Furthermore, an engagement recess47is formed in the slit46, deeper than the other portions of the connection portion43.

A hole53ais formed in the holding arm41near the boundary of the holding arm41and holding cylinder42. A hole53bextends from the hole53athrough the wall of the holding cylinder42. The base portion52of a fixing pin51having a T-shaped cross section is inserted in the hole53a. Further, a press spring55that presses the base portion52into the holding cylinder42is contained in the hole53a. The tip54of the fixing pin51is pressed by the spring55toward the insertion axis Ob of the endoscope16(into the holding cylinder42). In other words, the tip54of the fixing pin51is always pressed such that it projects into the holding cylinder42. Thus, the tip54of the fixing pin51is arranged so that it can project and retract into and from the holding cylinder42through the wall of the cylinder. The tip54of the fixing pin51is fitted in the slit46of the endoscope16held in the holding cylinder42, and is received in the engagement recess47. As a result, the endoscope16is fixed in position with respect to the axis of the holding cylinder42, and at the same time, is fixed in the circumferential direction of the holding cylinder42.

The width of the slit46is determined based on the diameter of the tip54of the fixing pin51, so that the tip54can be fitted in the slit46.

As described above, in the embodiment, a positioning mechanism for positioning the endoscope16at a predetermined position is realized by the holding cylinder42, fixing pin51, press spring55, slit46of the endoscope16and engagement recess47.

Referring again toFIG. 1, the optical positional relationship concerning the observation using the endoscope16will be described. As seen fromFIG. 1, the insertion axis Ob of the endoscope16is parallel to the axis Oa of the sheath1, and is displaced therefrom by the distance R. Accordingly, the observation optical axis Oo is pivoted about the axis Oa of the sheath1, always directed to the axis Oa.

Further, the angle θ formed between the focal distance f of the endoscope16and the observation optical axis Oo is given by

Point A, the focal point of the endoscope16on the observation optical axis Oo, is always positioned on the axis Oa of the sheath1. The point A is the center of the field of view, and is the axis about which the endoscope16is rotated by the rotary support mechanism40.

The operation of the endoscopic surgical system of the embodiment will be described. Firstly, the preparation executed before the sheath1and endoscope16are inserted into the body of a patient will be described.

As shown inFIG. 1, the sheath1and rotary ring5are made unrotatable relative to each other by the fastening screw15. The endoscope16is inserted into the holding cylinder42with the sheath1attached thereto. At this time, as shown inFIGS. 2A and 2B, the insertion is executed with the slit46of the connection portion43of the endoscope16aligned with the fixing pin51. The fixing pin51is fitted into the recess47of the slit46. At this time, the axial position of the holding cylinder42is adjusted so that the intersection of the axis Oa of the sheath1and the observation optical axis Oo is positioned at the point A. Further, the tip54of the fixing pin51is engaged with the engagement recess47, thereby fitting the endoscope16in the holding cylinder42firmly in both the axial and circumferential directions.

Thus, the endoscope16is held in the sheath1, thereby forming the endoscopic surgical system50. Then, the endoscopic surgical system50is inserted into the opening2formed in the body, e.g. the head, of the patient, as shown in FIG.1. At this time, the affected area3is positioned at the point A, i.e., the focus at which the axis Oa of the sheath1and the observation optical axis Oo intersect each other. In this state, the sheath1is fixed to, for example, an operating table by the holder arm10.

A description will now be given of how the affected area3is observed. An image of the affected area3is transmitted to the eyepiece portion22via the objective lens23, prism24, relay lens25and eyepiece27of the endoscope16. The image is further transmitted to the CCD31of the TV camera32via the imaging lens27of the interchangeable tip28. It is further transmitted from the CCD31to the TV monitor34via the controller33, whereby the image of the affected area3is displayed thereon.

To treat the affected area3, a surgical instrument58such as forceps is inserted into the space of the sheath1as shown in FIG.1. When starting the treatment, to facilitate the operation of the surgical instrument58, a surgeon rotates the TV camera32(CCD31) about the insertion axis Ob relative to the interchangeable tip28. At this time, the orientation of the observation image displayed on the TV monitor34is adjusted to be identical to that of the affected area to be actually operated.

A description will be then given of how the direction of observation is changed with the affected area3fixed at the center of the field of view. Firstly, the tab14is rotated to loosen the fastening screw15. After that, the rotary ring5is rotated about the axis Oa of the sheath1. At this time, the endoscope16is rotated about the axis Oa of the sheath1together with the holding cylinder42and arm41. The endoscope16is positioned so that the axis Oa is always separate from the insertion axis Ob by the distance R. In other words, the endoscope16is moved along the circle of the radius R using the axis Oa as its central point. The observation optical axis Oo draws a conical locus using the point A (affected area3) as the apex. Thus, the observation direction of the endoscope16is changed while the observation optical axis Oo is pivoted on the point A.

FIG. 3is a view assumed when the axis Oa inFIG. 1is viewed from above, showing various positions of the endoscope16. For example, there is a case where the surgeon wants to see the back of the affected area3as a front view, when the endoscope16is positioned as indicated by the solid line in FIG.3. At this time, the endoscope16is rotated through 180° about the axis Oa as indicated by the broken line in FIG.3. The point A of the observation field is positioned at the focal distance f of the endoscope16, and hence the affected area3is kept in focus. Therefore, the direction in which the affected area3is seen can be selected optionally.

If the TV camera32is rotated in accordance with the rotation of the endoscope16, the orientation of the observation image on the TV monitor34will differ from that of the affected area3which the surgeon actually observes. In light of this, the TV camera32is rotated relative to the interchangeable tip28to adjust the orientation of the observation image.

In the embodiment, the rotary support mechanism40is rotated with the rotary ring5engaged with the flange4of the sheath1. Further, the linear bar-like holding arm41holds the endoscope16. This means that the direction of the observation optical axis Oo of the endoscope16is limited by the mechanical position fixing. In other words, the support mechanism40enables the inner space of the sheath1to be used effectively, i.e., secures a wide operation space for the surgical instrument58.

This embodiment is applicable to a rigid-type endoscope having a particular shape that enables observation in a direction oblique to the insertion axis Ob. Further, since the embodiment does not require an optical deviating mechanism, it can exhibit optical performance identical to that of the conventional endoscopic observation.

In the embodiment, the position of the endoscope16is fixed by the fixing pin51for fixing the endoscope to the holding cylinder42. Alternatively, a light-guide connecting portion (not shown) incorporated in the endoscope16, for example, may be used as a positioning mechanism.

Referring toFIGS. 4 and 5, a second embodiment will be described. This embodiment is a modification of the first embodiment. In the second embodiment, elements similar to those of the first embodiment are denoted by corresponding reference numerals, and no detailed description is given thereof.

As shown inFIG. 4, in an endoscopic surgical apparatus60according to the second embodiment, a first support arm61is formed integrally as one body with the outer periphery of the sheath1. The first support arm61extends perpendicular to the axis Oa of the sheath1. A through hole63having a rectangular cross section is formed in the distal end of the first support arm61. A second support arm62having a rectangular cross section is inserted through hole63. The end of the second support arm62close to the through hole63is perpendicular to the first support arm61. The second support arm62is movable in the directions indicated by arrows64.

The second support arm62is bent into an L shape. The other end of the second support arm62remote from the through hole63is located parallel to the axis Oa of the sheath1. A block65is formed integrally as one body with the other end of the second support arm62. A through hole66having a rectangular cross section, similar to the through hole63of the first support arm61, is formed in the block65. The through hole66extends perpendicular to the through hole63and the other end of the second support arm62. A third support arm67having a rectangular cross section is inserted in the through hole66. The third support arm67is movable along the axis of the through hole66, i.e., in the directions, indicated by arrows68, perpendicular to the second support arm62. A TV camera32is detachably attached to the other end of the third support arm67by a fixing screw69. The arrows64are perpendicular to the arrows68, and both the arrows64and68are perpendicular to the axis Oa of the sheath1.

Referring toFIG. 5, the rotary support mechanism40for supporting the endoscope16will be described. A first holding arm71is formed integrally as one body with the inner surface of the rotary ring5, projecting therefrom. The projecting end of the first holding arm71serves as a guide portion72having a rectangular cross section. A second holding arm73is formed integrally as one body with the holding cylinder42, projecting therefrom. A guide hole74having a rectangular cross section is formed in the second holding arm73. The guide portion72is inserted in the guide hole74. As a result, the second holding arm73is supported so that it can move relative to the guide portion72in the directions indicated by arrows X. The directions of the arrows X are perpendicular to the axis Oa of the sheath1.

A screw hole76reaching the guide hole74is formed in the second holding arm73in the direction parallel to the axis Oa. A fixing screw84having a tab is screwed in the screw hole76. When the fixing screw84is screwed in the second holding arm73, the tip of the screw84is pressed against the sidewall of the guide portion72inserted in the guide hole74. The second holding arm73can be fixed to a desired portion of the first holding arm71by fastening the guide portion72.

The endoscope16employed in this embodiment is useful when the angle formed between the observation optical axis Oo and insertion axis Ob is varied from θ to, for example, θ′, as is indicated by the broken line in FIG.5.

The operation of the endoscopic surgical apparatus60according to the embodiment will be described.

InFIG. 5, when the fixing screw84is loosened, the second holding arm73is movable relative to the first holding arm71in a direction perpendicular to the axis Oa. Therefore, the second holding arm73is moved relative to the first holding arm71. The distance R between the insertion axis Ob of the endoscope16and the axis Oa of the sheath1is varied with the axes kept parallel. As a result, the endoscope16is moved as indicated by the broken line inFIG. 5, thereby selecting the angle θ′ of the observation optical axis Oo relative to the insertion axis Ob. This means that even if the endoscope16whose angle θ between the observation optical axis Oo and the axis Ob differs from that employed in the first embodiment is used, it can provide the same advantage as the first embodiment.

Further, as shown inFIG. 4, the endoscope16and rotary support mechanism40are rotated about the axis Oa of the sheath1. In this case, the rotation of the TV camera32is limited by the movement of the second support arm62relative to the first support arm61, and the movement of the third support arm67relative to the second support arm62. Instead, the interchangeable tip28rotates relative to the TV camera32. Accordingly, the position of the TV camera32is maintained even when the endoscope16is rotated about the axis Oa. This means that the observation image on the TV monitor34does not rotate.

In the second embodiment, even if endoscopes whose angles θ between the observation optical axis Oo and the axis Ob differ from each other are used, the direction of observation can be varied, with the center of the field of view fixed. Accordingly, various types of endoscopes can be used. Further, to change the direction of the observation optical axis Oo relative to the axis Oa of the sheath1, it is sufficient if the endoscope16is exchanged for a more appropriate one.

Further, as in the first embodiment, it is not necessary to adjust the position of the TV camera32when the endoscope16is rotated, thereby facilitating the operation.

Referring toFIG. 6, a third embodiment will be described. This embodiment is another modification of the first embodiment. In the third embodiment, elements similar to those of the first embodiment are denoted by corresponding reference numerals, and no detailed description is given thereof.

An endoscopic surgical system90according to the third embodiment employs a cylindrical sheath70to be inserted into an opening2formed in the body of a patient to observe and treat an affected area3. The sheath70has an axis Oc. A holding arm41projecting perpendicular to the axis Oc is formed integrally as one body with the inner periphery of a proximal opening (hand-side opening). A holding cylinder42provided with a hole42ahaving the axis Oc is formed integrally as one body with the distal end of the holding arm41.

An annular groove75having a V-shaped cross section is formed in the inner periphery of the hole42aof the holding cylinder42. An O-ring69is fitted in the groove75in a compressed manner, interposed between the outer peripheral surface of the connecting portion43of the endoscope16and the inner peripheral surface of the holding cylinder42. In this structure, the endoscope16is fixed in position but can rotate about the axis Oc. Thus, the rotary support mechanism40employed in this embodiment comprises the holding arm41and holding cylinder42. Further, an end of a connecting arm79as a connector is fixed to the intermediate portion of the holding arm41. The other end of the connecting arm79is fixed to the TV camera32.

The interchangeable tip28and TV camera32are connected to the upper end of the endoscope16as in the first embodiment. The interchangeable tip28and TV camera32are rotatable to each other as in the first embodiment.

As seen fromFIG. 6, the TV camera32is connected to a control unit77that includes a video signal processing circuit and image reversing circuit. The control unit77is connected to a TV monitor78.

The distal end of the sheath70positioned close to the affected area3is in the form of a circular truncated cone. A reflection mirror80in the form of a circular truncated cone, which serves as an optical reflection mechanism and has the axis Oc, is attached to the entire distal end of the sheath70. The reflection mirror80is tapered toward the proximal opening side of the sheath70at an angle γ with respect to the axis Oc.

The endoscope16and sheath70has the following optical positional relationship. Assume that the intersection of the observation optical axis Oo and the reflection surface of the reflection mirror80is P. InFIG. 6, f1indicates the distance between the object23of the endoscope16and a point P on the reflection surface of the reflection mirror80. Further, f2indicates the distance between the point P on the reflection surface of the reflection mirror80and the point A. In this case, the relationship “f1+f2=f (f indicates the focal distance of the endoscope16as in the first embodiment)” is established. The point A as the focal point of the endoscope16on the observation optical axis Oo is always on the axis Oc of the sheath70. Thus, the distance S between the axis Oc and point P, and the angle γ of the reflection mirror80with respect to the axis Oc are set.

Also in this embodiment, the sheath70is fixed to, for example, an operating table by an arm similar to the holder arm10of the first embodiment.

The operation of the endoscopic surgical system90will be described. Firstly, the preparation executed before the endoscope16and sheath70are inserted into the opening2of the body of a patient will be described.

The insertion section21of the endoscope16is inserted from above into the hole42aof the holding cylinder42of the sheath70. At this time, the connection portion43of the endoscope16is pressed by the O-ring69. Accordingly, the endoscope16is firmly connected to the holding cylinder42and can rotate about the axis Oc. The endoscope16and sheath70kept in this state are inserted into the body of a patient. The sheath70is positioned so that the endoscopic surgical system90and affected area3have a predetermined positional relationship. At this time, the sheath70is secured to, for example, an operating table by the holder arm10.

A description will now be given of how the affected area3is observed. An image of the affected area3is reflected by the conical reflection mirror80. After that, the image is transmitted, as in the first embodiment, to the interchangeable tip28via the objective lens, prism, relay lens and eyepiece of the endoscope16. The image is further transmitted from the imaging lens of the interchangeable tip28to the CCD of the TV camera32. As a result, the image of the affected area3is displayed on the TV monitor78via the control unit77. By virtue of the image reversing circuit of the control unit77, the image displayed on the TV monitor78is reversed. Thus, the image is prevented from being displayed in a mirror image state.

To start an actual operation, the entire sheath70is rotated to rotate the TV camera32, so that the orientation of the observation image displayed on the TV monitor78is identical to that of the affected area3the surgeon actually observes.

A description will now be given of how the direction of observation is changed with the affected area3fixed at the center of the field of view. The endoscope16is rotated about the axis Oc relative to the holding cylinder42. At this time, the observation optical axis Oo draws a conical locus at an angle θ to the axis Oc. Further, by the conical reflection mirror80, the observation optical axis Oo draws a conical locus using the point A as the apex. Thus, the observation direction of the endoscope16can be changed with the center of the field of view fixed at the point A. For example, if the surgeon wants to see the back of the affected area3, it is sufficient if the endoscope16is rotated through 180° about the axis Oc.

At this time, the rotation of the TV camera32is prevented by the connecting arm79. Accordingly, relative rotation occurs between the interchangeable tip28and TV camera32, and hence the orientation of the observation image on the TV monitor78is maintained unchanged.

In this embodiment, to change the direction of observation with the center of the field of view fixed, it is sufficient if the endoscope16is rotated about the insertion axis Ob. Thus, the operation of the system is very simple. Further, since the endoscope16does not move about within the sheath70, the endoscope16does not easily interrupt the operation of, for example, the surgical instrument58.

This embodiment may be modified such that the holding arm41, hole42aand holding cylinder42are not used, and the TV camera32is connected to the sheath70by the connecting arm79. In other words, the endoscope16is suspended using the connecting arm79. In this modification, the interchangeable tip28connected to the TV camera32and the endoscope16are made rotatable relative to the TV camera32.

Referring now toFIGS. 7A,7B and8, a fourth embodiment will be described. The fourth embodiment is a modification of the third embodiment. In this embodiment, elements similar to those of the third embodiment are denoted by corresponding reference numerals, and no detailed description is given thereof.

FIG. 7Ais a side view illustrating the distal end of the sheath70, andFIG. 7Bis a schematic view of the distal end of the sheath70, viewed from the affected area3side.

In the third embodiment, the reflection mirror80as an optical reflection mechanism is provided at the distal end of the sheath70positioned close to the affected area3. On the other hand, in the fourth embodiment, a plurality of flat mirrors80a-80hare employed instead of the reflection mirror80. The flat mirrors80a-80hprovide the same function as that of the conical reflection mirror80.

Specifically, a plurality (e.g.8) of flat mirrors80a-80hare inclined at the angle γ to the axis Oc as in the third embodiment, and are arranged in a circle.

In the third embodiment, an image is obtained by rotating the endoscope16continuously. In the fourth embodiment, the endoscope16is rotated step by step so that the observation optical axis Oo is aligned with one of the flat mirrors80a-80h, thereby selecting the position of the endoscope16. This can also change the direction of observation with the affected area3fixed at the center of the field of view, as in the third embodiment.

The use of the flat mirrors80a-80has optical reflection members in this embodiment prevents a resultant optical image from being deformed, thereby facilitating the observation.

Further, an optical adaptor82that contains an erecting prism81as shown inFIG. 8may be used as an image reversing mechanism. In this case, a mirror image resulting from one reflection by the endoscope16is reversed. Specifically, an erect image results from three internal reflections, inside the erecting prism81, of the image received from the endoscope16. This prism81makes it unnecessary to employ the image reversing circuit in the control unit77of the third embodiment. Accordingly, the same control unit as the control unit33of the first embodiment can be used in the fourth embodiment.

If the optical adaptor82is used in the first embodiment, to adjust the orientation of the observation image, it is sufficient if the erecting prism81is rotated by operating the tab83of the optical adaptor82. Thus, the orientation of the observation image can be adjusted by a simple operation. The erecting prism81can be more finely rotated by an electromotive operation.

Referring toFIGS. 9 and 10, a fifth embodiment will be described.FIG. 9is a schematic view partly in section, illustrating the entire structure of an endoscopic surgical system100according to the fifth embodiment.

Firstly, an endoscope125for use in the endoscopic surgical system100will be described. The endoscope125is a rigid-type endoscope.

As seen fromFIG. 9, the endoscope125of the fifth embodiment comprises an elongated insertion section126and eyepiece portion (hand-side section)127located at the hand-side end of the insertion section126. The insertion section126has an insertion axis Oi. The insertion section126includes an objective lens128and relay lens129for transmitting an image, from the affected area103, sent from the objective lens128. An eyepiece130is provided in the eyepiece portion127.

An optical adaptor132having an imaging lens131is formed integral with the eyepiece portion127. A TV camera134with a CCD133is formed integral with the upper end of the optical adaptor132. The imaging lens131of the optical adaptor132can be moved along the observation optical axis Oo by a first motor135. By moving the imaging lens131, the focal point of the endoscope125at the affected area103side can be changed. Further, the TV camera134is connected to the TV monitor via a controller33. The endoscope125also comprises an illumination optical system (not shown) and a light guide (not shown) for guiding the light emitted from a light source (not shown).

A cylindrical sheath101having a distal opening and proximal (hand-side) opening is inserted into an opening102formed in, for example, the head of a patient. The sheath101has an axis Of. The affected area103is observed by the endoscope125inserted in the opening102through the sheath101, and is treated.

An endoscope support arm141is formed integral with the outer periphery of the sheath101and a cylinder143. The cylinder143has a holding hole142. The axis of the holding hole142of the cylinder143is identical to the axis Of of the sheath101(i.e., identical to the insertion axis Oi and observation optical axis Oo).

A screw hole145is formed in the outer peripheral wall of the cylinder143, so that it extends perpendicular to the axis Of. When a fixing screw146is screwed into the screw hole145, using a knob147, it is pressed against the insertion section126of the endoscope125fitted in the cylinder143, thereby fixing the endoscope125to the cylinder143.

The sheath101is fixed to, for example, an operating table (not shown), by a holder arm104connected to the endoscope support arm141.

An outwardly projecting annular flange105is formed at the hand-side opening of the sheath101. The axis of the flange105is identical to that of the sheath101, Of. A rotary cylinder110having a distal opening and proximal opening is received in the sheath101so that it can rotate about the axis Of of the sheath101.

An outwardly projecting annular flange106is formed at the hand-side opening of the rotary cylinder110. The axis of the flange106is identical to that of the sheath101, Of. A screw portion107ais provided at the outer periphery of the flange106. Further, a cylindrical fastening ring108having a screw portion107bengaged with the screw portion107ais provided at the outer periphery of the flange106. An internally projecting annular flange108ais formed at distal end of the cylindrical fastening ring108. The ring108is fitted on the side of the flange105opposing the flange106with the flange105interposed therebetween parallel to the axis Of.

A first reflection mechanism is provided at the distal opening of the rotary cylinder110positioned close to the affected area3, and consists of a solenoid118for converting electric energy into mechanical energy. The shaft117, i.e. axis Og of the solenoid is perpendicular to the cross-sectional plane of the rotary cylinder100that passes through the axis Of. A first reflection mirror115is provided on a swing arm116. The swing arm116is attached to the shaft117. It is preferable that the first reflection mirror115is inclined by 45° to the axis Of. The swing arm116can pivot between a first position in which the first reflection mirror115is positioned on the axis Of, and a second position in which the mirror115is retracted from the axis Of, as is indicated by the arrow in FIG.9.

A second reflection mechanism is provided opposing the first reflecting mechanism. In other words, when the swing arm116is positioned in the first position, the second reflection mechanism is on the extension of the axis of the swing arm116. The second reflection mechanism includes a second motor123fixed to the rotary cylinder110, and a shaft122, parallel to117. This shaft122rotates around the axis Oh. The shaft122has a block121that rotates in accordance with the rotation of the shaft122. A second reflection mirror119is attached to the block121.

A structure that connects the endoscope125to the sheath101will be described. The insertion section126of the endoscope125is inserted through the cylinder143, and the boundary portion of the insertion section126and eyepiece portion127is held by the cylinder143. The screw146is screwed to thereby fix the endoscope125to the cylinder143in a desired position. At this time, the insertion axis Oi of the endoscope125is identical to the axis Of of the sheath101.

Referring toFIG. 9, a description will now be given of the optical positional relationship between the first and second reflection mirrors115and119, and the imaging lens131of the optical adaptor132.

In the state indicated by the solid line inFIG. 9, the first reflection mirror115is positioned on the observation optical axis Oo of the endoscope125, inclined by α with respect to the observation optical axis Oo. On the observation optical axis Oo reflected by the first reflection mirror115, the second reflection mirror119is positioned inclined by β with respect to the axis Of of the sheath101. The observation optical axis Oo reflected by the first reflection mirror115intersects the axis Of at point A.

The position of the imaging lens131of the optical adaptor132is controlled such that the intersection A is identical to the focal point of the endoscope125. This position control is executed by a control mechanism153of the electric system described below.

As seen fromFIG. 9, the first motor135is connected to a first driving circuit155that is connected to the control mechanism153. The control mechanism153is connected to a second driving circuit154that is connected to the above-mentioned second motor123.

The endoscopic surgical system100of this embodiment is provided with an operation board150. The board150has a seesaw-type ON/OFF switch151of two levels, and a dial switch152having a variable resistance and enabling stepless output. The dial switch152is connected to the control mechanism153. The control mechanism153has a logic circuit (not shown) for controlling the driving circuits154and155according to the position of the dial switch152.

The ON/OFF switch151is connected to the solenoid118via a third driving circuit158.

The operation of the fifth embodiment will be described. Firstly, the preparation executed before the endoscope125and sheath101are inserted into an opening102formed in the body of a patient will be described.

The endoscope125is inserted into the hole142of the holding cylinder143. A surgeon then checks the image of the affected area103displayed on the TV monitor34. To facilitate the operation of a surgical instrument (not shown), the endoscope125, optical adapter132and TV camera34are rotated to adjust the orientation of the observation image on the TV monitor34to that of the affected area actually seen. Then, the knob147is turned to fasten the fixing screw146, thereby pressing the insertion section126of the endoscope125to hold it in the cylinder143.

A description will now be given of how the affected area103is observed. An image of the affected area103is transmitted to the optical adaptor132via the objective lens128, relay lens129and eyepiece130of the endoscope125. The image is further transmitted from the imaging lens131of the optical adaptor132to the CCD133of the TV camera134. As a result, the image of the affected area3is displayed on the TV monitor34via the controller33.

The fifth embodiment enables: {circle around (1)} frontal observation using the endoscope; {circle around (2)} change, using the mirrors, of the direction of observation, with the center of the field of view fixed; and {circle around (3)} change of the angle of the observation direction {circle around (2)} (change of the angle of the observation optical axis Oo). {circle around (1)}, {circle around (2)} and {circle around (3)} will be described in detail.

When the ON/OFF switch151of the operation board150is pushed in one direction (e.g. turned off), a signal is transmitted to the solenoid118via the third driving circuit158, thereby pivoting the solenoid118in the direction indicated by arrow161. More specifically, the shaft117is rotated and the swing arm116attached to the shaft117is swung. As a result, the first reflection mirror115is retracted to the position indicated by the broken line in FIG.9. In this state, the observation optical axis Oo of the endoscope125is directly in line with the affected area103. Subsequently, the dial152is operated to drive the first motor135via the first driving circuit155, thereby adjusting the focal point of the endoscope125.

When the ON/OFF switch151is pushed in the other direction (e.g. turned on), the first reflection mirror115returns to the position indicated by the solid line inFIG. 9, as a result of the operation opposite to the above.

Re: {circle around (2)} Change, using mirrors, of direction of observation, with center of field of view fixed:

In the state shown inFIG. 9, the rotary cylinder110is rotated about the axis Of relative to the sheath101. Accordingly, the first and second reflection mirrors115and119are rotated about the axis Of. As a result, the observation optical axis Oo draws a conical locus using the point A as the apex. Thus, the direction of observation of the affected area103is changed with the center of the field of view fixed, as in the aforementioned embodiments. At this time, since the endoscope125and TV camera134do not rotate, the observation image displayed on the TV monitor34does not rotate.

Re: {circle around (3)} Change of angle of observation direction {circle around (2)} (change of angle of observation optical axis Oo):

When the dial switch152of the operation board150is rotated, a signal corresponding to the amount of rotation of the dial switch152is input to the control mechanism153. The control mechanism153supplies the first and second driving circuits155and154with respective signals corresponding to the information obtained from the logic circuit that is incorporated in the mechanism. The first and second driving circuits155and154output driving signals to the first and second motors135and123to rotate them, respectively.

When the second motor123rotates, the shaft122and block121rotate simultaneously. As a result, the angle β of the second reflection mirror119formed integral with the block121changes. Accordingly, the angle ω between the observation optical axis Oo and the axis Of of the sheath101changes. On the other hand, when the first motor135rotates, the imaging lens131is moved. As a result, the focal point of the endoscope125is moved on the observation optical axis Oo. Thus, the focal point of the endoscope125is adjusted.

The control mechanism153may have an auto-focusing function. Also in this case, when the angle of the observation optical axis Oo to the axis Of of the sheath101varies, the control mechanism153controls the driving signals supplied to the driving circuits155and154. As a result, the focal point on the observation optical axis Oo is always positioned on the axis Of. If, for example, the angle ω becomes large, the first motor135is rotated to move the imaging lens131so that the focal point of the endoscope125will be positioned closer to the lens131.

By virtue of the above operations, the angle ω for observing the affected area103can be optionally changed as shown in FIG.10.

Although the fifth embodiment uses optical reflection, the observation image is not reversed since reflection occurs twice. Therefore, in the fifth embodiment, it is not necessary to incorporate an image reversing circuit in the control unit33as in the third or fourth embodiment. Accordingly, the fifth embodiment can be made simple in structure.

To change the direction of observation with the center of the field of view fixed, it is sufficient if the first and second reflection mirrors115and119are rotated. In other words, it is sufficient if the rotary cylinder110is rotated relative to the sheath101. Accordingly, the endoscope125does not move about within the sheath101, which means that the endoscope125does not easily interrupt the operation of, for example, a surgical instrument (not shown).

The angle of the observation optical axis Oo for observing the affected area103can be changed by changing the angles of the first and second reflection mirrors115and119. Accordingly, the affected area103can be observed from any desired angle. In synchronism with the change of the observation angle, the focal point of the endoscope125can be changed. Thus, the affected area103can be kept in focus even when the observation angle is changed, and hence a good observation image can be always obtained. Moreover, the auto-focusing function enables this focusing operation to be executed automatically, with the result that no complicated operation is required during a surgical operation.

Furthermore, the first reflection mirror115is retractable. Accordingly, observation from the front side can be performed by retracting the first reflection mirror115and using the endoscope as a direct-vision endoscope. Therefore, the endoscope can be used in various kinds of operations.

In each of the above-described embodiments, it is preferable that the hollow sheath to be inserted into the body of a patient is a cylinder member having a completely circular cross section. However, it may have an elliptic cross section as shown inFIG. 11, or a square, rectangular or parallelogram cross section, or a polygonal cross section. The axis of the sheath usually passes through the center of a circular cross section if the sheath is cylindrical, the intersection of the major and minor axes if it has an elliptic cross section, and the intersection of the diagonal lines if it has a rectangular cross section. In other words, it is sufficient if the axis of the sheath passes through substantially the center of the sheath.

Although in each embodiment, the sheath has opposite openings of the same forms and areas, they may have different forms and areas. For example, the sheath171shown inFIG. 12is of a conical shape that has a wide proximal opening and narrow distal opening. The sheath172shown inFIG. 13is formed of three cylindrical portions172a,172band172carranged coaxially and having diameters gradually reduced in this order. The cylindrical portions172a,172band172cmay be connected to each other such that their axes are not arranged in line.

In addition, the observation mechanism is not limited to the endoscope, but may be, for example, a microscope. Further, a pointer or reticle may be provided on the field of view of the endoscope or microscope for pointing the center of the field of view (observation optical axis). In this case, a known imaging mechanism, which includes a CCD or monitor for picking up the field of view of the endoscope or microscope, is provided to display the pointer or reticle. This structure enables reliable observation of a rotating object to be executed with the object kept at the center of the field of view.