WO2012059739A2

WO2012059739A2 - Handle and surgical instrument

Info

Publication number: WO2012059739A2
Application number: PCT/GB2011/052088
Authority: WO
Inventors: David Main
Original assignee: Surgical Innovations Limited
Priority date: 2010-11-03
Filing date: 2011-10-27
Publication date: 2012-05-10
Also published as: WO2012059739A3; GB201018532D0

Abstract

A handle (2) for a surgical instrument is described. The handle comprises a housing (4) for attachment to an outer shaft of a surgical instrument and defining a longitudinal axis. An adjustment member (6) comprises a first bevel gear (12) mounted for rotation about an adjustment axis perpendicular to the longitudinal axis. A second bevel gear (26) is engaged with the first bevel gear and mounted to rotate about an axis parallel to the longitudinal axis. A translatable member (36) is provided for attachment to an inner member of a surgical instrument and is configured to move relative to the housing along the longitudinal axis in response to rotation of the second bevel gear. In one embodiment the handle is for a minimally invasive surgical instrument having a segment string at its distal end. The configuration of the handle allows one handed use. The adjustment member can be operated by the same hand which is holding the handle. A surgical retractor instrument (44) including the handle is also described

Description

HANDLE AND SURGICAL INSTRUMENT

The present invention relates to a handle for a surgical instrument and a surgical instrument comprising the handle. In particular, the present invention relates to handles for endoscopic and/or minimally invasive surgical instruments and those surgical instruments which include an operative portion which is actuated by moving one part relative to another.

In endoscopic and minimally invasive surgical techniques, it is known to provide an instrument which comprises an operative portion at the distal end of an elongate shaft. One part of the operative portion is coupled to the elongate shaft and another part is coupled to a second shaft, typically disposed within the outer shaft. Relative movement of the two shafts results in movement of the operative portion. Examples of surgical instruments operated in this way include scissors and dissectors. This form of actuation is also used in surgical retractors for use in endoscopic or laparoscopic surgery.

In order to be inserted through as small an incision as possible, a retractor for endoscopic or laparoscopic surgery has two configurations: a first, low profile configuration for insertion into the body and a second, larger configuration for engaging the part of the anatomy which is to be retracted. One form of retractor suitable for endoscopic surgery is a segment string. In a segment string instrument, a chain of connected segments have a filament running through them. Drawing the filament proximally shortens the length of the filament and causes the segment string to bend into a retraction configuration. Handles for use with endoscopic and minimally invasive surgical instruments are known. In general such handles are in the form of a pistol grip or scissors. Movement of the pistol grip or scissors directly corresponds to movement of the shafts of the operative portion. This limits the range of movement available from the handle to a single stroke of the pistol grip or scissors. It also limits the force that can be applied, because the required range of movement at the operative portion places a limit on the mechanical advantage that can be achieved through a single operation of the pistol grip or scissor handles. This can make pistol grip or scissor handles difficult to use with tools such as segment strings, or other tools which may require a relatively high force to be applied to operate the operative portion or end effector.

Prior art segment string retractors may be provided with a handle incorporating a rotatable adjustment member and a translating member. The rotatable adjustment member is located on a proximal end of the handle, coaxial with the longitudinal axis defined by the handle. The adjustment member has a thread which engages a corresponding thread on a translatable member coaxially located within the adjustment member. The filament of the segment string is attached to the translatable member. The segment string can then be activated by rotating the adjustment member. This moves the translatable member by the action of the screw thread and either shortens or lengthens the filament, moving the retractor between the low profile configuration and the retraction configuration. However, such a handle cannot be operated with one hand. It requires a user to hold the body of the handle with one hand and activate the adjustment member with the other.

Accordingly, the present invention provides a handle for a surgical instrument in which an adjustment member is provided for rotation about an axis which is perpendicular to a longitudinal axis of the handle. This improves the ergonomics of the positioning of the adjustment member and allows it to be operated whilst holding the instrument one handed.

According to the present invention, there is provided a handle for a surgical instrument, wherein the handle comprises a housing for attachment to an outer shaft of a surgical instrument and defining a longitudinal axis; an adjustment member comprising a first bevel gear mounted for rotation about an adjustment axis perpendicular to the longitudinal axis; a second bevel gear engaged with the first bevel gear and mounted to rotate about an axis parallel to the longitudinal axis; and a translatable member for attachment to an inner member of a surgical instrument and configured to move relative to the housing along the longitudinal axis in response to rotation of the second bevel gear. The first and second bevel gears enable the rotation of the adjustment member about an axis perpendicular to the longitudinal axis to be converted into rotation about an axis parallel to the longitudinal axis or about the longitudinal axis itself, enabling a more ergonomic configuration of the handle.

The housing is for attachment to an outer shaft of a surgical instrument and the translatable member is for attachment to an inner member of a surgical instrument. In both cases, this attachment may be direct or indirect. This attachment allows movement of the translatable member to result in relative movement of the inner member versus the outer shaft of an attached surgical instrument, actuating an operative portion of the surgical instrument. The adjustment axis may intersect the longitudinal axis or be offset from the longitudinal axis, depending on the configuration of the first and second bevel gear.

The rotation of the second bevel gear may be transferred into a translation of the translatable member in any suitable manner. In a preferred embodiment, wherein at least a portion of the external surface of the translatable member is threaded; the second bevel gear is mounted to rotate about the longitudinal axis and defines a through bore which is coaxial with the longitudinal axis and at least a portion of the through bore is threaded. The threaded portion of the external surface of the translatable member is engaged with the threaded portion of the through bore.

The use of threads enables the mechanical advantage between the adjustment member and the translatable member to be adjusted by the pitch of the threads. The mechanical advantage may also be adjusted by altering the gear ratio between the first and second bevel gears. The threaded connection also enables fine relative movement of the translatable portion to be provided by the adjustment member. A further advantage is that it allows the translatable member to remain in a position set by a user even if a longitudinal force is exerted on the translatable member.

The adjustment member may have at least two-fold rotational symmetry about the adjustment axis. The reference to at least two-fold symmetry means that the adjustment member adopts an identical configuration about the adjustment axis at least twice during a rotation through 360°. In other words, the adjustment member may have some form of rotational symmetry. In some embodiments, the adjustment member may be essentially circular.

The adjustment member may have an external surface defining a plurality of indentations for receiving at least one digit of a user. This can enable the adjustment member to be gripped for rotation more easily in use.

In some embodiments, the handle may be configured such that, in use, the handle can be held in one hand and the adjustment member is positioned such that it falls between the index finger and thumb of a user. This improves the ergonomics of the handle.

In other embodiments, the handle may have a front end and a rear end, and in use the front end is closer to the surgical instrument than the rear end, and the adjustment member is positioned closer to the front end than to the rear end. This also improves the ergonomics of the handle.

It can also be advantageous in some embodiments for the adjustment axis to intersect the longitudinal axis of the handle. This positions the adjustment member centrally on the longitudinal axis, with respect to the width of the handle about the longitudinal axis. This can improve ergonomics, ensuring that the adjustment member extends the same distance each side of the longitudinal axis, when the adjustment member is generally circular or has rotational symmetry.

The handle of the present invention can be used with a wide variety of surgical instruments, including, and not limited to, scissors, dissectors and retractors.

In some embodiments, the handle may form an integral part of a surgical instrument. In other embodiments, the handle may comprise a removable connection system for connection to a variety of different surgical instruments, or for reuse of the handle with different surgical instruments. When the handle comprises a connection system the surgical instruments to which it is connected can be single use or reusable. According to another aspect of the present invention, there is provided a surgical instrument comprising an operative portion; an outer shaft having a longitudinal bore extending from the operative portion and attached to a first part of the operative portion; an inner member which is disposed within the longitudinal bore and attached to a second part of the operative portion; and a handle according to any one of the preceding claims. Thus, rotation of the adjustment member of the handle results in relative movement of the first and second parts of the operative portion.

Preferably, the operative portion is a retractor. The improved mechanical advantage of the present invention enables reliable deployment of a retractor between low profile and retraction configurations when relatively high forces may need to be applied to a filament to bend a segment string into the retraction configuration. When used with a retractor, the first part of the operative part is a segment string and the second part of the operative portion is the filament. The filament and the inner member may be the same component when used with a retractor.

According to a further aspect of the present invention, there is provided a surgical retractor comprising a handle as described above with or without any of the optional features also discussed.

Embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings, in which:

Figure 1 depicts a diagrammatic representation of a perspective view of a handle according to an embodiment of the present invention;

Figure 2 depicts a diagrammatic representation of a cross-section through the handle of Figure 1;

Figure 3 depicts a diagrammatic representation showing an exploded diagram of the handle of Figure 1; and

Figure 4 depicts a handle of Figure 1 attached to a surgical retractor. Referring to Figures 1, 2 and 3, the construction of a preferred embodiment of the invention will now be described. In Figures 1-3, the handle is described in isolation of an attached surgical instrument. It will be appreciated that the handle can be used with a wide variety of surgical instruments, including scissors, dissectors and retractors.

According to a first embodiment, a handle 2 comprises a housing 4 on which an adjustment member 6 is mounted. The adjustment member 6 is generally circular in form having rotational symmetry. It comprises a plurality of indentations 8 sized to receive a user's digit. As can be appreciated from Figure 1, the positioning of the adjustment member 6 on the housing 2 enables the indentations 8 to be engaged by a thumb and index finger of a user in use. In order to enhance the ergonomics of the handle in use, the housing 4 comprises an additional extension portion 10 at its proximal end. This ensures that the housing extends a longer distance proximal of the adjustment member than distal of the adjustment member, so that the adjustment member 6 is located toward the front end of the handle and closer to the surgical instrument itself. This configuration offers improved ergonomics because the extension 10 is contained generally within a user's palm in use.

The internal construction of the handle to enable operation of a surgical instrument can be understood more clearly with reference to the cross-section of Figure 2 and the exploded diagram of Figure 3. The adjustment member 6 is connected to a bevel gear 12 by means of a keyed bore 14 which corresponds to a keyed projection 16 of the bevel gear 12. Thus, in use, rotation of the adjustment member 6 rotates the bevel gear 12. The bevel gear 12 includes a central bore 18 defining an axis of rotation. A pin 20 is provided to support the adjustment member and bevel gear for rotation about an adjustment axis defined by the pin.

Gear housing 22 contains the bevel gear 12, pin 20 and adjustment member 6. It is secured in the housing 4 by screws 24. The bevel gear 12 engages a corresponding bevel gear 26 located within the housing 4. Bevel gear 26 is contained within the housing 4 coaxial with a longitudinal axis 28 defined by the housing. Longitudinal axis 28 is also coaxial with the outer shaft 30 of a surgical instrument attached to the handle. A proximal portion 32 of bevel gear 26 extends proximally, along the longitudinal axis. It contains a central, longitudinal bore 34 for receiving a translatable member 36. Bevel gear 26 and its proximal portion 32 are retained within the housing 4 by two pins 38. These pins 38 extend through the walls of the housing to support the proximal end of proximal extension 32. As a result the bevel gear 26 is constrained from moving longitudinally within the housing but can still rotate about the longitudinal axis 28 in response to rotation of adjustment member 6. The proximal portion of the longitudinal bore 34 comprises a screw thread that engages a corresponding threaded section on translatable member 36. For clarity, the threads are not indicated in the exploded diagram of Figure 3 and are shown diagrammatically with reference numeral 38 in the cross-section of Figure 2.

As can be seen most clearly in Figure 3, the translatable member 36 includes longitudinal grooves at least along its distal most portion. These grooves are engaged by pins 38 and serve to prevent rotation of translatable member 36 about the longitudinal axis. Thus, the translatable member is constrained against rotation about the longitudinal axis so that rotation of the bevel gear 26 and proximal extension 32 results in translational movement of the translatable member 36 by the interaction of the threaded portions 40.

In use, a shaft 30 of a surgical instrument is attached to the housing 4 of the handle 2. An inner member, such as a central filament or inner shaft, of the surgical instrument is then attached to translatable member 36. In use, a user can hold the handle in a single hand and engage opposite sides of the adjustment member with a thumb and index finger of a single hand. Thus, the surgical instrument can be operated using only a single hand. In this embodiment, the detail of the bevel gear is show diagrammatically by an angled surface. The person skilled in the art is aware of the various different configurations which can be adopted by a bevel gear to translate the rotation of the adjustment member 6 about an adjustment axis defined by pin 20, which is perpendicular to longitudinal axis 28, into a rotation about longitudinal axis 28.

Depending on whether the handle is desired to be reusable or disposable, it may be manufactured from medical grade metal, metal alloys, composites or plastics materials. Figure 4 depicts a handle according to the embodiment of Figure 1 attached to a surgical retractor 44. Retractor 44 comprises a segment string 46 at its distal end. A filament (not shown) is connected to the translatable member of the handle so that operation of the adjustment member moves the filament relative to an outer shaft 48 of the retractor 44, which is attached to the housing 4. As depicted in Figure 4, the retractor is shown in a retraction configuration, when the filament has been shortened by moving translatable portion 36 proximally within the housing 4. Alternative configurations of the handle are possible in other embodiments within the scope of the invention, which is defined by the appended claims. For example, the adjustment member 6 may have other forms, providing that it rotates about an axis which is perpendicular to the longitudinal axis.

Claims

1. A handle for a surgical instrument, wherein the handle comprises:

a housing for attachment to an outer shaft of a surgical instrument and defining a longitudinal axis;

an adjustment member comprising a first bevel gear mounted for rotation about an adjustment axis perpendicular to the longitudinal axis;

a second bevel gear engaged with the first bevel gear and mounted to rotate about an axis parallel to the longitudinal axis; and

a translatable member for attachment to an inner member of a surgical instrument and configured to move relative to the housing along the longitudinal axis in response to rotation of the second bevel gear.

2. A handle according to claim 1 , wherein at least a portion of the external surface of the translatable member is threaded;

the second bevel gear is mounted to rotate about the longitudinal axis and defines a through bore which is coaxial with the longitudinal axis and at least a portion of the through bore is threaded; and

the threaded portion of the external surface of the translatable member is engaged with the threaded portion of the through bore.

3. A handle according to claim 1 or 2, wherein the adjustment member has at least two-fold rotational symmetry about the adjustment axis.

4. A handle according to any one of the preceding claims, wherein the adjustment member has an external surface defining a plurality of indentations for receiving at least one digit of a user.

5. A handle according to any one of the preceding claims, wherein in use the handle can be held in one hand and the adjustment member is positioned such that it falls between the index finger and thumb of a user.

6. A handle according to any one of the preceding claims, wherein the handle has a front end and a rear end, and in use the front end is closer to the surgical instrument than the rear end, and the adjustment member is positioned closer to the front end than to the rear end.

7. A handle according to any one of the preceding claims, wherein the adjustment axis intersects the longitudinal axis.

8. A surgical instrument comprising:

an operative portion;

an outer shaft having a longitudinal bore extending from the operative portion and attached to a first part of the operative portion;

an inner member which is disposed within the longitudinal bore and attached to a second part of the operative portion; and

a handle according to any one of the preceding claims.

9. A surgical instrument according to claim 8, wherein the operative portion is a retractor.

10. A surgical retractor comprising a handle according to any one of claims 1 to 7.