WO2012087112A1

WO2012087112A1 - Expandable retractor for minimally invasive surgery and a method of manufacturing the same

Info

Publication number: WO2012087112A1
Application number: PCT/NL2010/050875
Authority: WO
Inventors: Gert-Jan KLEINRENSINK
Original assignee: Erasmus University Medical Center Rotterdam
Priority date: 2010-12-21
Filing date: 2010-12-21
Publication date: 2012-06-28

Abstract

The invention relates to an expandable retractor for minimally invasive surgery comprising a flap of material conceived to be used for supporting tissue or organ during retraction thereof, said flap of material being arranged in a collapsed state for facilitating introduction thereof in a vicinity of the said tissue or organ, a string attached to the flap of material for enabling retraction, wherein the expandable retractor further comprises: an inflatable chamber integrated with a portion of a surface of the flap of material for causing expansion of the said flap pursuant to a force built-up by a fluid in the inflatable chamber in use, wherein a dimension of the inflatable chamber along the surface of the flap is smaller than a total surface area of the flap. The invention further relates to a retraction system and a method of manufacturing the same.

Description

Title: Expandable retractor for minimally invasive surgery and a method of manufacturing the same

FIELD

The invention relates to retractor devices used for supporting and deflecting tissue in the operation site. More in particular, the invention relates to an expandable retractor for minimally invasive surgery.

The invention further relates to a retractor system and a method of manufacturing the same.

BACKGROUND OF THE INVENTION

An embodiment of a retractor as is set forth in the opening paragraph is known from WO 2009/032611. The known retractor comprises a fabric cooperating with a bladder provided for improving rigidity of the deployed fabric retractor in use. However, in order to facilitate deployment of the fabric the latter is provided with deployment strings which are conceived to be pulled by a surgeon in use.

It is a disadvantage of the known retractor that the surgeon needs to operate the deployment strings, which may be cumbersome, or even may be hampered by entanglement of the strings or their rupture.

A further embodiment of a retractor as is set forth in the opening paragraph is known from WO 2009/070517, wherein a flap of pliable material, is provided with an inflatable chamber conceived to be filled with a suitable fluid in use for stiffening the flap. It is a disadvantage of the known retractor that the pliable flap is not provided in a collapsed condition for insertion into an operation site which complicates handling thereof in use. SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved retractor whose deployment in use is simplified, yet is enabled in a reliable way. To this end the expandable retractor according to the invention comprises:

- a flap of material conceived to be used for supporting tissue or organ during retraction thereof, said flap of material being arranged in a collapsed state for facilitating introduction thereof in a vicinity of the said tissue or organ,

- a string attached to the flap of material for enabling retraction, wherein the expandable retractor further comprises:

- an inflatable chamber integrated with a portion of a surface of the flap of material for causing expansion of the said flap pursuant to a force built- up by a fluid in the inflatable chamber in use, wherein a dimension of the inflatable chamber along the surface of the flap is smaller than a total surface area of the flap.

The technical measure of the invention is based on the insight that by providing a collapsed flap with an inflatable chamber provided on a surface of the retractor material, said chamber being dimensioned to extend over a relatively small portion of the surface area of the flap, a force, building up inside the inflatable chamber upon filling it in use, can reliably facilitate expansion of the collapsed flap in use, i.e. when the flap is positioned in the target region inside the patient.

It will be appreciated that the retractor according to the invention may be rolled-up or collapsed in any other suitable way for facilitating insertion thereof in the target area during use.

In an embodiment of the expandable retractor according to an aspect of the invention the inflatable chamber is at least partially provided along a periphery of the flap of material.

It is found to be advantageous to provide the inflatable chamber causing the retractor to expand in use along the periphery of the flap. It will be appreciated that in such arrangement the inflatable chamber may be provided near or at the edge of the flap. When the extendable retractor is inserted into the patient in the collapsed state and the inflatable chamber is being filled in use, the fluid urging from a suitable inlet port inside the inflatable chamber shall cause the latter to expand and to push the collapsed portions of the expandable retractor away from the inlet port thereby causing the retractor to deploy. It will be appreciated that a total time necessary for the expandable retractor to deploy according to the invention is about 1 - 3 seconds, which is faster than in the prior art devices when deployment strings are used. In addition, the expandable retractor according to the invention is deployed in a reliable way as the direction of the deployment is controlled by the

configuration of the inflatable chamber. The expandable retractor may be shaped as a rectangle, the inflatable chamber being provided at least along the longer side of the rectangle. However, it will be appreciated that other geometries of the retractor are envisaged, including, but not limited to a circle, en ellipse, a square, or the like.

In a still further embodiment of the expandable retractor according to the invention, the inflatable chamber is C-shaped, all portions of the C-shape being provided along the periphery of the flap of material. It will be appreciated that preferably, the C-shape is positioned along the portions of the retractor which have a degree of freedom, as at least a part of a surface area of the retractor may be fixed to a surgical device, such as an insertion member.

In a still further embodiment of the expandable retractor according to the invention the inflatable chamber is T-shaped, a base of the T- shape being provided along the periphery of the flap of material, a leg of the T- shape extending across the flap of material. This particular embodiment is also suitable when the material of the retractor is affixed to a suitable insertion member. In this case the leg of the T-shape may be provided along an inner portion of the surface area of the flap and the base of the T-shape may be provided as the distal part of the flap (with respect to the insertion member). Accordingly, when the expandable retractor is provided in the target area in use, a force built-up inside the T-shape inflatable chamber will cause the retractor to expand from the collapsed state.

In a still further embodiment of the expandable retractor according to the invention, the retractor is rolled up from a periphery of the flap material towards a fixation area on an insertion member, the inflatable chamber comprising a fluid port in the region of said fixation area.

Such configuration is found advantageous as it minimizes the total volume of the expandable retractor, which is important for the minimally invasive surgery.

In a still further embodiment of the expandable retractor according to the invention the fluid port comprises a valve for preventing deflation of the inflatable chamber in use.

It is found to be advantageous to provide the expandable retractor with a valve which is integrated with the inflatable chamber, preferably for inflation a suitable gas is used. However, saline solution may be envisaged as well. Preferably, in order to deflate the bag it is punctured as the valve provided at the fluid inlet port does not allow the fluid to recoil back. It is found that the inflatable chamber may be adequately filled using a 20 ml syringe. However, it will be appreciated that the volume of the inflatable chamber is directly proportional to a surface area of the retractor conceived to be deployed using such inflatable chamber.

In a still further embodiment of the expandable retractor according to the invention, two or more strings are provided for manipulating the expanded retractor in use. Preferably, said strings are attached to respective lateral peripheries of the flap of material. More preferably, the strings are rolled-up (or collapsed in any other suitable way) with the retractor flap. When the retractor flap is deployed, the strings appear and may be manipulated. Such arrangement is advantageous as it prevents entanglement of the strings. In a still further embodiment of the expandable retractor according the invention the flap of material used for retractor is knitted, woven or comprises a mesh.

Such choice of materials is found to be advantageous as it minimizes the total mass of the retractor minimizing the force which has to be built-up inside the inflatable chamber for enabling total deployment of the flap. Preferably, according to a still further embodiment of the expandable retractor according to the invention the flap of material comprises woven polypropylene or a polyester mesh.

In a still further embodiment of the expandable retractor according to the invention the flap of material of the retractor is provided with orientation indicators.

For example, the orientation indicator may comprise colour indicators and/or other markers, such as arrows, alpha-numerical information, including scale, or the like. This is found to be advantageous for enabling due control of the deployment of the retractor inside the patient as well as for simplifying handling of the retractor during minimally invasive interventions.

In a still further embodiment of the expandable retractor according to the invention the inflatable chamber comprises polyethylene. This material is found to be advantageous due to its elastic properties. The flap of material used for manufacturing a retractor may be about 200 mm long and may have thickness in the range of 0.2 - 0.4 mm.

The invention further relates to a retraction system comprising an insertion member provided with a collapsed expandable retractor as is set forth in the foregoing.

The invention still further relates to a method method of manufacturing a retractor system for minimally invasive surgery comprising the steps of:

- providing a flap of material conceived to be used for supporting tissue or organ during retraction thereof, - arranging said flap of material in a collapsed state for facilitating introduction thereof in a vicinity of the said tissue or organ,

- providing a positioning member attached to the flap of material for enabling retraction,

- providing an inflatable chamber integrated with a portion of a surface of the flap of material for causing expansion of the said flap pursuant to a force built-up by a fluid in the inflatable chamber in use, wherein a dimension of the inflatable chamber along the surface of the flap is smaller than a total surface area of the flap. Preferably, the method according to the invention comprises the step of attaching the collapsed retractor to a surgical instrument, such as an insertion member.

These and other aspects of the invention will be discussed in more detail with reference to drawings, wherein like reference numerals refer to like elements. It will be appreciated that the drawings are presents for illustrative purposes and may not be used for limiting the scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 presents a schematic view of the expandable retractor according to the invention in a deployed state;

Figure 2 presents a schematic view of particular configurations of the inflatable chamber arranged on a surface area of the retractor material;

Figure 3 presents a schematic view of the retractor system according to the invention;

Figure 4 presents a schematic view of the inlet port comprising the valve in the retractor according to the invention;

Figure 5 presents a schematic view of the embodiments of the retractor material.

DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 presents a schematic view of the expandable retractor according to the invention in a deployed state. The expandable retractor 10 comprises a flap of material 2, which may be affixed on a suitable surgical instrument, such as an insertion tube 3. In use the flap 2 may be used to support and preferably enclose the small intestine to retract tissue. The flap 2 may be fabricated from a piece of a suitably knitted, woven or mesh-like material.

In accordance with an aspect of the invention the flap 2 is provided with an inflatable chamber, having portions 2a and la formed to enable deployments of the flap (stored in a collapsed state) during inflation of the chamber. The inflatable chamber la, 2a may be filled using a suitable fluid, such as a gas or liquid. The fluid may be provided using an inlet port, arranged in fluid communication with a unidirectional valve. It will be appreciated that although in this embodiment a T-shaped inflatable chamber is shown, other configurations capable of causing deployment of the flap 2 upon filling are contemplated.

Preferably, the T-structure has a base which substantially parallel to a direction of the longitudinal axis of the surgical instrument. This has an advantage that the fluid streaming inside the inner volume of the inflatable chamber la, 2a shall exhibit sufficient force to cause the flap to deploy from a collapsed state. The preferable way of collapsing the flap 2 is its rolling from the distal periphery PI towards the proximal periphery P2.

It will be appreciated that the cross-section of the inflatable chamber 2a, la may change along the area of the flap from a larger cross section near the proximal periphery P2 towards a smaller cross-section near the distal periphery. This may be advantageous as once the flap has started unfolding, still smaller force is needed to continue the unfolding process.

However, the cross-section of the inflatable chamber may be the same over the area of the flap. In an alternative embodiment, the base of the inflatable chamber 2a may be similarly arranged, wherein the beam la may be replaced by two beams directed to the opposed corners of the flap 2. Such arrangement may be advantageous as it may have an increased mechanical rigidity.

It a still further embodiment, the inflatable chamber may be H- shaped so that both peripheries PI and P2 have increased mechanical rigidity.

It will be appreciated that although the expandable retractor 10 according to the invention is provided with displacement bodies IB, 1C, such as strings, these bodies are used for retracting a suitable organ, such as intestines, and not for deployment of the flap 2. Preferably, the displacement bodies IB, 1C are stored inside the collapsed flap 2 and emerge only upon the flap 2 is fully deployed. This has an advantage that the strings are not entangled or destroyed.

Figure 2 presents a schematic view of particular configurations of the inflatable chamber arranged on a surface area of the retractor material. It will be appreciated that a plurality of suitable configurations of the inflatable chamber adapted to enable deployment of the flap from the collapsed condition is possible. As has been mentioned earlier, the preferred way of storing the retractor according to the invention is to roll it up about a periphery so that a substantially coaxial device is produced, see 21, 21a. Preferably, the flap is secured on an insertion tube 21a.

In according with an aspect of the invention the inflatable chamber covers a relatively small surface area of the flap of the retractor as it is used primarily for deploying the retractor flap. The inflatable chamber may be provided by blown film extrusion and may be suitable secured on a surface of the flap. For example, the inflatable chamber may be provided substantially along the edges of the flap 22, see items 25a, 24a, 23a. In this embodiment the configuration of the inflatable chamber may be used either to deploy the flap from the rolled-up condition or from a folded-up condition (not shown). In an alternative embodiment, the inflatable chamber may be T- shaped, having a base portion 26a and a beam 27a, which may be substantially perpendicularly arranged with respect to the base portion 26a, or,

alternatively, under an angle with respect thereto. Two or more beams of the type 27a may be provided. However, it will be appreciated that even when a plurality of beams of the type 27a is provided the total area of the inflatable chamber is less, or substantially less than the total surface area of the flap 28.

Figure 3 presents a schematic view of the retractor system according to the invention. In this figure a cross-section 30 of a patient P undergoing minimally invasive operation is shown. The retractor according to the invention provided on an insertion tube 37 is being inserted in a collapsed state into the abdominal cavity in a vicinity of the organ O conceived to be displaced. In order to deploy the retractor, a fluid is supplied into the inflatable chamber 34 using a syringe filled with saline. Due to the action of internal forced caused by the pressurized liquid in the inflatable chamber, the retractor flap 32 deploys in the region near the organ O. The retractor can be manoeuvred using strings 36, 35 which are attached to the flap 32. An endoscope 33 may be used for visualizing the procedure.

In order to provide the surgeon with orientation means, the flap 32 may be provided with markers, such as colour marks or suitable signs, such as arrows, letters or a scale. It will be appreciated that a plurality of different markers may be envisaged, which lie within the ordinary skill of the artisan.

Figure 4 presents a schematic view of the inlet port comprising the valve in the retractor according to the invention. View 40a depicts

schematically a top view of an embodiment of the expandable retractor 40 according to an aspect of the invention. In this particular embodiment a T- shaped inflatable chamber is shown, comprising portions 41a, 41b in fluid communication with each other and with the inflow port 41.

View 40b depicts schematically an internal flow pattern inside the inflatable chamber. The proximal portion of the inflatable chamber is arranged in such a way that the inflow of a liquid cannot recoil away from the inflatable chamber. For this purpose the inlet portion 41a is spaced so that the internal flow Al is directed into the main cavity of the inflatable chamber A2 via a passageway A2. The valve built-in the inflatable chamber is arranged in such a way that the inflowing liquid will close the opening upon recoil. Should the liquid flow back towards the inlet port, it will first flow into an extra

compartment 43 first expanding it and by doing so closing the opening towards the inlet port 41a via a pre-compartment 42.

The view 40c depicts schematically a geometrical representation of the valve. The fluid inflow id depicted by F, the first compartment of the inflatable chamber is depicted by 42 and the second (main) compartment of the inflatable chamber is depicted by 43. The valve 44 is displaceably arranged between the compartments 42 and 43. It will be appreciated that a width a of the first compartment 42 may be substantially smaller than the width b of the second compartment 43. The flow patterns are schematically indicated by the arrows Al, A2.

The view 40d schematically depicts a cross-section of the valve integrated in the inflatable chamber. The valve 44 is displaceable between the compartments 42 and 43 closing off the inlet port should the liquid urge to recoil away from the inflatable chamber.

It is noted that such integrated valve inside the inflatable chamber comprising a displaceable portion is particularly suited to operate with liquids. For gases an additional valve component may be envisaged.

Figure 5 presents a schematic view of the embodiments of the retractor material. The view 50a schematically depicts an embodiment of a flap material manufactured from a woven material. It will be appreciated that a great plurality of possibilities exists so that many different biologically inert materials may be used for manufacturing the flap 501. Item 502 schematically depicts a details view of the flap material 501. Woven polypropylene mesh may be used for manufacturing the flap material 501. The flap 501 may be about 0.3 mm thick.

The view 50b schematically depicts an embodiment of the flap 510 wherein it is manufactured using a mosquito-like mesh material, preferably manufactured from polyester. Item 512 depicts an enlarged detail of a portion of the flap 502. The flap 510 may be 0.25 mm thick.

The view 50c depicts schematically a further embodiment of the flap material 520 comprising grid knitted cells. PET may be selected as a suitable material for bridging the gap between required flexibility of the flap and the strength of the material. It is found that the grid manufactured from the PET material comprising fibres cross-linked with each other has excellent properties yet low manufacturing costs.

It is found to be advantageous to use polypropylene for

manufacturing the flap material as is ensured sufficient tear strength yet being thin enabling due collapsing thereof. The flap according to the invention may be 200 mm in length and a thickness in the range of 0.15 - 0.35 mm, preferably about 0.25 mm. The flap may be wrapped about a 3 mm insertion tube resulting in a body having diameter of about 10mm. Such configuration is suitable to be used with a 10 mm trocar.

It will be appreciated that while specific embodiments of the invention have been described above, that the invention may be practiced otherwise than as described. In addition, isolated features discussed with reference to different figures may be combined.

Claims

1. An expandable retractor for minimally invasive surgery comprising:

- an inflatable chamber integrated with a portion of a surface of the flap of material for causing expansion of the said flap pursuant to a force built-up by a fluid in the inflatable chamber in use, wherein a dimension of the inflatable chamber along the surface of the flap is smaller than a total surface area of the flap.

2. An expandable retractor according to claim 1, wherein the inflatable chamber is at least partially provided along a periphery of the flap of material.

3. An expandable retractor according to claim 2, wherein the inflatable chamber is C- shaped, all portions of the C- shape being provided along the periphery of the flap of material.

4. An expandable retractor according to claim 2, wherein the inflatable chamber is T-shaped, a base of the T-shape being provided along the periphery of the flap of material, a leg of the T-shape extending across the flap of material.

An expandable retractor according to any one of the preceding claims 2 - 4, wherein the flap of material is rolled from the said periphery towards a fixation area, the inflatable chamber being provided along the said fixation area.

An expandable retractor according to claim 5, wherein the inflatable chamber comprises a fluid port in the region of said periphery.

An expandable retractor according to any one of the preceding claims, wherein the fluid port comprises a displaceable valve ifor preventing deflation of the inflatable chamber in use.

An expandable retractor according to any one of the preceding claims, wherein two strings are provided, said strings being attached to respective lateral peripheries of the flap of material.

An expandable retractor according to any one of the preceding claims, wherein the flap of material is knitted, woven or comprises a mesh.

An expandable retractor according to claim 9, wherein the flap of material comprises woven polypropylene or a polyester mesh.

An expandable retractor according to any one of the preceding claim, wherein the flap of material is provided with orientation indicators.

An expandable retractor according to any one of the preceding claims, wherein the string or strings are conceived to be collapsed together with the flap of material.

An expandable retractor according to any one of the preceding claims, wherein the inflatable chamber comprises polyethylene.

14. An expandable retractor according to any one of the preceding

claims, wherein the flap of material is about 200 mm long and has thickness in the range of 0.15 - 0.35 mm.

15. A retraction system comprising an insertion member provided with a collapsed expandable retractor according to any one of the preceding claims.

16. A method of manufacturing a retractor system for minimally

invasive surgery comprising the steps of:

- providing a flap of material conceived to be used for supporting tissue or organ during retraction thereof,

- arranging said flap of material in a collapsed state for facilitating introduction thereof in a vicinity of the said tissue or organ,

- providing an inflatable chamber integrated with a portion of a surface of the flap of material for causing expansion of the said flap pursuant to a force built-up by a fluid in the inflatable chamber in use, wherein a dimension of the inflatable chamber along the surface of the flap is smaller than a total surface area of the flap.

17. The method according to claim 16, further comprising the step of attaching the collapsed flap of the expandable retractor to a surgical instrument, such as an insertion member.