Surgical retractor

A retractor for use in surgery, such as chest surgery, comprises two arms (4,6) each adapted to carry a blade (14,16) engageable with one side of an incision, the two arms (4,6) being connected by a pivot (8) at one end portion such that the arms (4,6) can be pivoted between a closed position and an adjustable open position in which the arms define a substantially V-shaped configuration in which the blades (14,16) maintain the sides of the incision in inclined relation. The arms are moved to the open position by means of a curved rack (20) carried by one of the arms (6) and a pinion (28) carried by the other arm (4), the pinion (28) being releasably lockable to retain the arms in the open position by a ratchet and pawl mechanism.

FIELD

This invention relates to retractors for use in surgery, and more particularly, but not exclusively, to retractors for use in chest surgery.

BACKGROUND

When a patient is incised for surgery, the sides of the incision are parted and are held apart by a retractor so that the surgeon has the required access to the patient's body. Conventionally, previously proposed retractors for chest surgery comprise two parallel arms, with blades disposed thereon to engage the sternum (breastbone). The operation of these retractors is such that the retractor arms remain parallel throughout their range of motion, resulting in the sides of the incision being parted by the same amount along the length of the retractor.

With particular regard to cardiac (heart) surgery, the ribs attached to the lower (inferior) portion of the sternum are longer and are provided with more cartilage and greater elasticity than the ribs attached to the upper portion of the sternum. This results in the upper (superior) ribs having less tolerance for displacement. The use of parallel-opening retractors for spreading the sternum for cardiac operations exerts greater force on the upper ribs, which may fracture. Another disadvantage of these retractors is that their use in spreading the sternum may result in excessive traction on the nerves (brachial plexus) leading to the patient's arm. Damage to these nerves can cause weakness or long term loss of feeling in the patient's ring and little fingers. One way to avoid applying excessive stress to the upper ribs is to position the retractor as low as possible. However, this approach does not allow the retractor to be placed in the most advantageous position for chest surgery and can cause damage to the sternum by having mainly the edges, rather than the full surfaces, of the blades exerting pressure on the sides of the incision.

During surgery, it is often necessary to open the incision both horizontally and vertically. Typically, two separate retractors have been required for this, one for the horizontal opening and another for the vertical opening. The applicant has determined that it would be beneficial to have a single retractor which could part the sternum with minimal displacement at the upper end and maximal displacement at the lower end, a “V”-shaped displacement, in both the horizontal and vertical planes.

SUMMARY

In accordance with the present invention, there is provided a retractor for use in surgery comprising two arms each adapted to carry a blade engageable with one side of an incision, the two arms being connected by a pivot at one end portion such that the arms can be pivoted between a closed position and an adjustable open position in which the arms to define a substantially V-shaped configuration in which the blades maintain the sides of the incision in inclined relation, and means for retaining the arms in the open position.

Preferably, each of the arms carries at least one sleeve rotatably mounted around the arm, the blade being mounted by the sleeve and the sleeve being lockable in a selected angular orientation whereby to change the angular orientation of the blade. This allows a V-shaped displacement of the retractor in both the horizontal and vertical planes.

Preferably, the blade is movable into a selected position along the arm. In one particularly preferred form there is an assembly of such sleeves on the arm lockable in end to end relation in a variable angular orientation and the blade is retained by co-operation between different pairs of adjacent sleeves to permit adjustment in blade position. The sleeves may also be interchangeably positioned on the arm to permit further adjustment of blade position.

Preferably, the blades are mounted by balls engaging within sockets formed by adjacent end faces of adjacent sleeves.

Preferably, the blades are replaceable and are available in a range of sizes.

Further according to the invention, there is provided a retractor for use in surgery comprising two arms each adapted to carry means engageable with the zone of an incision, the two arms being connected by a pivot at one end portion such that the arms can be pivoted between a closed position and an adjustable open position in which the arms define a substantially V-shaped configuration, and means for retaining the arms in the open position.

In one form the means engageable with the zone of an incision comprise means adapted to grip on the surface of an organ such as the heart.

The retractor in accordance with the preferred embodiment of the invention is principally for use in chest surgery and comprises two arms4,6which are connected by a pivot8at their upper ends such that the arms4,6can be pivoted between a closed position in which the arms are substantially parallel and an open position in which the arms4,6are inclined to define a substantially V-shaped configuration. The arms4,6each carry at least one blade14,16for contact with tissue of the patient on either side of an incision such that opening of the arms4,6opens the incision in a V-shape, the blades14,16extending from the arms4,6via support arms14a,16arigidly connected to the blades. Preferably, the blades14,16are replaceable and are available in a range of sizes to provide for various sizes and/or obesities of patients. The two arms4,6are provided with locking means18to releasably hold the arms4,6in a variable open position.

In the preferred embodiment, the locking means18includes an arm in the form of a curved rack20, the curve being a circular arc centred substantially at the pivot8. One end of the rack20is fixed to an end sleeve22of the arm6by a pivot24. A toothed outer edge26of the rack20engages a driving pinion28, rotatably mounted on an end sleeve30of the other arm4, throughout a range of openings provided by the length of the rack20. The pinion28is associated with a ratchet and pawl mechanism having a first “ratchet” state in which rotation of the pinion28in only one direction is allowed such that only opening movement of the arms4,6is possible. A second “free” state allows both opening and closing movement of the arms4,6. The state of the mechanism can be changed by switching of a pawl release32. The pinion28is drivable by means of a crank handle34in order to open the arms4,6and hence to open the incision. The crank handle34is detachable from the pinion28to reduce interference during surgery.

The sleeve30is removably mounted on the arm4. The arm4also carries further sleeves36,38,40between the sleeve30and a sleeve-like abutment42at the upper end portion of the arm4. The sleeve30and adjacent sleeve36are engageable via serrations or other formations on their adjacent end faces in order to lock the sleeves30,36against relative rotation. The adjacent end faces of the sleeve40and the abutment42also have similar serrations or other formations engageable to lock that sleeve40against rotation relative to the abutment42. The end faces of the intermediate sleeve38and the adjacent faces of the sleeves36and40are shaped to cause rotational interlocking of the three sleeves36,38,40. These adjacent interlocking faces of the three sleeves36,38,40are also configured to define sockets44,46for receiving selectively a mounting ball48at the end of the support arm14acarrying the blade14. The assembly of the four sleeves30,36,38,40on the arm4can be firmly secured to the arm4by means of a knurled nut50threadedly mounted at the lower end portion of the arm4. When tightened the nut50will cause the uppermost sleeve40to be locked against the abutment42and due to the interengaging end surfaces of the other sleeves30,36,38, the assembly of four sleeves30,36,38,40will be firmly locked to the arm4against relative rotation. The ball48at the end of the support arm14acarrying the blade14will also be firmly locked in the socket44or46between the sleeves36,38by tightening the nut50. By slackening the nut50, the ball48can be removed from one of the sockets44or46between the sleeves36and38and relocated in the other socket44or46between the sleeves38and40in order to adjust the position of the blade14lengthwise of the arm4to suit a particular patient. Prior to final tightening of the nut50, the ball48is able to be swiveled within the socket44,46to facilitate adjustment in the orientation of the blade.

It is to be noted that the sleeves36and40are of different lengths and are capable of being interchangeably positioned on the arm4to provide the possibility of further options for the lengthwise positioning of the blade14on the arm4.

A corresponding set of sleeves22,52,54,56which act in the manner just described is mounted on the other arm6. These sleeves also have the same range of adjustment in position to facilitate adjustment in the position of the blade16along the arm6and adjustment of its orientation by swiveling of its mounting ball within the socket defined by the interlocking faces of the adjacent sleeves.

All of the sleeves22,30,36-40,52-56are removable from the two arms4,6for cleaning purposes and the sleeves22and30are interchangeably mounted on the arms4and6in order to change the direction of projection of the rack20. The handle34may engage the pinion28from either side allowing the sleeve30to be used on either arm4,6.

When the nuts50are loosened, the angular positions of the sleeves36-40,52-56on the arms4,6can also be adjusted in order to change the angular orientation of the blades14,16about the axis of the arms and the blades14,16can be locked in their selected orientation by tightening the nuts50after adjustment of the angular position of the sleeves. This change in angular orientation may be necessary to suit the type of opening required by the surgeon. For example during chest surgery, the surgeon may require the incision to be opened not only horizontally but also one side of the incision to be lifted vertically relative to the other side to facilitate access (seeFIG. 5). Thus the deep aspect of the chest wall on one side may be exposed, allowing access to the internal mammary (thoracic) artery for harvest. The adjustment in the angular position of the blades14,16facilitates this.

Blades14,16of differing design can be interchangeably mounted on the arms4,6in order to adapt the retractor for different uses.FIG. 4, for example, illustrates blades with simple cranked legs andFIG. 5, for example, illustrates blades with legs of a more complex shape.

The retractor of the preferred embodiment in opening into a V-shaped configuration has the advantage of reducing the displacement of the upper portion of the chest during sternal surgery so that there is less risk of damage to the patient, in particular to the upper ribs and to the brachial plexus. The single retractor can be used to open the incision both vertically and horizontally, with the free end of the curved rack20extending in either direction, due to the interchangeability of the various components on the arms. The position of the blades14,16can be altered to accommodate different sizes of chest and/or incision. Another advantage is the minimisation of extremities likely to cause interference during surgery. The retractor provides a rigidly held opening which offers improved access and vision to the surgeon.

The retractor can be completely disassembled for cleaning. As previously discussed, all of the sleeves are removable from the arms. The rack20is detachable from the sleeve22by sliding the pivot24of the rack20out of a slot-like pivot mounting24aof the sleeve22. The pivot8by which the two arms4,6are pivotally connected consists of a pivot pin8aon one of the arms releasably engageable in a slot-like pivot mounting8bon the other of the arms, whereby the two arms can be disconnected by sliding the pin8aout of the mounting8b.

The pivot24, in addition to allowing detachment of the rack20, also provides limited freedom for movement of the rack20during use to permit ease of tension from the rack20and thereby ease of operation of the pawl release32.

Optionally, clamps may be provided for application externally to the sleeves for specific applications such as valve retractor blades, beating heart stabilising devices, pericardial retractors, or holders for mister/blower devices.

The retractor described is not useable only for heart surgery but also is of benefit in other forms of surgery, for example abdominal surgery. A retractor in accordance with the invention designed specifically for abdominal surgery may have arcuately curved arms rather than straight arms as illustrated.

Although in the embodiment illustrated the arms mount the removable sleeves by which the blades are clamped, in alternative constructions provision for the removable sleeves may be omitted, with the arms being of a diameter such that blades can be clamped directly to the external surfaces of the arms. This construction will suffice in situations where the torque applied to the blades during use does not necessitate the mounting arrangement particularly described herein. In this form of the retractor, it is not necessary for the arms to be of circular cross-section and arms of other suitable form for the attachment of blades and other components can be provided, for example arms of rectangular cross-section or arms of flattened strip-like form.

A substantially smaller version of the retractor just described may be of benefit in other forms of surgery, such as “beating heart” surgery. In this version the arms do not carry retractor blades, but instead are of a generally flattened shape with small spikes, suction pads, and tape holders to grip on the surface of the heart and thereby to stabilise the segment of the surface of the heart defined between the two arms in their V-shaped open state. This form of retractor still includes the ratchet-type locking means18with the curved rack.

The embodiment has been described by way of example only and modifications are possible within the scope of the invention.

Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.