Surgical stapler for colorectal anastomosis

Abstract

A surgical stapler, adapted to mutually suture a rectal stump and a colic stump of a patient in a colorectal anastomosis surgery, comprises a handling rod, which includes at one of its ends a cup (10) of hollow cylindrical shape, a sectioning and suturing mechanism, and a tip (12), adapted to axially engage with a stem (18) integral with an enlarged head (16), so as to cause the stem (18) to translate and axially bring the head (16) closer to the cup (10), in such a way as to insert a radial formation (20), protruding radially with respect to the stem (18) or to the tip (12), and to drag the entire terminal suture of the rectal stump within said cup (10), without tearing the tissue of said rectal stump.

Description

[0001] Surgical stapler for colorectal anastomosis

[0002] Field of the invention

[0003] The present invention generally relates to the field of medical and surgical devices; in particular, the invention concerns a surgical stapler for colorectal anastomosis.

[0004] Prior art

[0005] Mechanical surgical staplers suitable for performing sutures in colorectal anastomosis surgery are known, which provide for the resection of a portion of the intestine of a patient, and the subsequent reconnection of the resulting colic and rectal stumps by suturing their terminal edges.

[0006] The transanal mechanical anastomosis according to Knight Griffen currently represents the most widely practiced solution in this field.

[0007] In particular, in this context, the use of so-called “double stapler” type staplers has become widespread, which comprise a handling rod (suitable to be operated by an operator), at the end of which is present a loader assembly, which is fitted into the rectal stump (pre-sutured with a traditional surgical linear stapler) and includes a cup of hollow cylindrical shape, from which a tip extends to engage the stem of a mushroom- shaped head, fitted into the colic stump (which is thus sutured in turn).

[0008] The tip is movable in such a way as to draw the head towards the cup, until the two stumps are brought into mutual contact. At this point, a sectioning and suturing mechanism (contained in the loader assembly) is activated, which projects beyond the cup a blade and a plurality of staples, which sever a central portion of the rectal stump and the colic stump, and suture to one another the latter.

[0009] Examples of devices of the aforementioned type are known from documents US 2021 / 0219978 Al and WO 2022071214 Al. It is noted in literature that the average risk of anastomotic leakage (a phenomenon also known as “anastomotic leak”), in the case of colorectal anastomosis after transanal mechanical anastomosis according to Knight Griffen, is estimated to be in the order of 8%. However, in the case histories reported in the literature, a very wide range of incidence of such complication is observed, ranging from 1% to 25%. Such a wide variation is presumably linked to additional risk factors, such as the location of the neoplasm (anastomoses closer to the anal margin are at higher risk), and the need to use multiple surgical stapler reloads for the resection of the rectum, in addition to patient-related factors such as, for example, age, smoking, obesity, or previous adjuvant chemotherapy.

[0010] The risk of anastomotic leak has adverse effects on the health of the patient. Among the direct effects, it is noted that the appearance of a leak in the postoperative course leads to a significant increase in morbidity and mortality, and exposes the patient to the risk of a further surgery and serious infections and sepsis that can even lead to the death of the patient. Even in the best cases, where a further surgery is not necessary, “conservative” treatment leads to a significant increase in hospitalisation time (with an increase in related complications), and to a longer time interval before the start of a possible adjuvant chemotherapy (if required), with worsening of the oncological outcome.

[0011] Furthermore, the higher the expected leak rate, the greater the tendency of the surgeon to “protect” the anastomosis with a stoma (protective ileostomy or colostomy) upstream, where the risk is considered unacceptable (for example, in the case of patients with significant comorbidities, who could not face the occurrence of a complication, or patients in whom the timely start of postoperative adjuvant chemotherapy is considered of fundamental importance). This results in a worsening of the patient’s quality of life and the need for a second surgery to close the stoma.

[0012] Since sigmoid-rectal surgery (for oncological or other reasons) is extremely widespread, it is easy to imagine that even a minimal reduction in the anastomotic leak rate would lead to very significant advantages both on the surgical / oncological outcome and consequently on the reduction in the number of protective stomas that may become necessary. A significant contributing factor to the occurrence of anastomotic leaks is the phenomenon of the so-called “dog-ears” (otherwise known in surgical technique as “dog-ears”), consisting in the undesired formation of tissue loops due to the use of a circular surgical stapler (which staples the rectal stump to the colic stump) on the rectilinear profile of the pre-sutured rectal stump (due to the previous sectioning of the rectum with a linear surgical stapler).

[0013] It is noted that, by eliminating such “dog-ears”, the formation of four points of lower resistance (both mechanical and vascular) of the anastomosis would be avoided, resulting in a clear reduction in the rate of anastomotic dehiscence.

[0014] Various solutions aimed at reducing the risk of anastomotic dehiscence have been proposed in the prior art, such as the variant with vertical sectioning of the rectum, reinforcement of the anastomosis with transanal suture stitches, the “NICE” procedure, the “pull-through” anastomosis, and the elimination of “dog-ears” using sutures. This demonstrates the need perceived by the colorectal surgical field for a reduction of this feared complication.

[0015] One proposed solution in the art is described in the article by Sameh Hany Emile, Samer Hani Barsom, Ahmed Hossam Elfallal, Steven D. Wexner: “Comprehensive literature review of the outcome, modifications, and alternatives to double- stapled low pelvic colorectal anastomosis”, Surgery, August 2022. In this article, a technique for eliminating “dog-ears” is reported, in which no episodes of anastomotic stenosis were recorded, with a leak rate of 0.9%.

[0016] The technique would therefore appear to achieve the desired results, but the surgical act by which this result is obtained involves the placement of a transfixing stitch to the suture, which is passed in both directions and then knotted. This procedure, especially if performed laparoscopically (which is currently the most widely adopted approach for colorectal surgery), involves a technically complex gesture, beyond the reach of a colorectal surgeon who does not possess long experience. Furthermore, the article reports a “dog-ear” elimination rate of 93.6%, thus with a non-negligible margin of failure. These circumstances, understandably, limit the possibility of performing an effective and lasting colorectal anastomosis.

[0017] A further example of surgical stapler is known from document US 2013 / 175315 Al, wherein, however, the colic stump is sutured at a through hole made in the stem of the mushroom- shaped head, at a certain distance therefrom, which entails a more extensive use of biological tissue (of the colic stump), which is however destined to be sacrificed in the subsequent removal performed by the sectioning and suturing mechanism, at the moment of joining the colic stump to the rectal stump. Therefore, such a solution proves to be impactful in terms of the amount of biological tissue that is sacrificed to perform the operation.

[0018] Summary of the invention

[0019] The purpose of the present invention is to overcome the aforementioned problems.

[0020] In particular, the object of the present invention is to provide a device that allows the elimination of “dog-ears” in an automatic manner and through a gesture that is easily reproducible even by surgeons with less experience, making transanal mechanical anastomosis without “dog-ears” a new universal practice.

[0021] To achieve such result, a surgical stapler is provided which is equipped with an accessory suitable for causing the entire linear suture of the rectal stump to re-enter into the cup, prior to the stapling of the latter with the colic stump, so that the contact surface between the two stumps is mutually more congruent, which consequently eliminates the “dog-ears”.

[0022] In fact, by dragging the suture of the rectal stump into the cup, a flat crown-shaped surface of the latter remains exposed at the top (substantially corresponding to the edge of the cup), which provides a planar support for the opposite end of the colic stump. In this way, when the two stumps are brought close together, they can abut one against the other along a substantially flat surface, without flaps or folds being present at the interface between the two that could create “dog-ears” when the two stumps are sutured together. Such an accessory of the stapler may be a fixed or expandable element, configured to protrude radially from the stem of the mushroom- shaped head or from the tip, in such a way as to be insertable into the cup, dragging therein the pre-sutured portion of the rectal stump.

[0023] A surgical stapler according to the present invention makes it possible to achieve multiple advantages, including the possibility of performing end-to-end mechanical anastomoses in the absence of “dog-ears”, the requirement of a simple technical gesture (easily reproducible even for less experienced surgeons), and the implication of minimal adaptations (purely mechanical) of devices already existing and widely used and tested.

[0024] The above-mentioned and other objects and advantages are achieved, according to one aspect of the invention, by a surgical stapler for colorectal anastomosis having the features defined in claim 1. Preferred embodiments of the invention are defined in the dependent claims.

[0025] Brief description of the drawings

[0026] The functional and structural features of some preferred embodiments of a surgical stapler according to the invention will now be described. Reference is made to the accompanying drawings, wherein:

[0027] - figures l(a)-(h) schematically show a sequence of steps to be performed for a traditional colorectal anastomosis with transanal mechanical anastomosis according to Knight Griffen;

[0028] - figure 2 is a schematic side view of a head of a surgical stapler, adapted to engage the colic stump and provided with a radially protruding formation from its stem, which is configured to be inserted into a cup placed at the end of a handling rod of the stapler, according to an embodiment of the invention;

[0029] - figure 3 is a schematic side view of the head in figure 2 engaging the colic stump, while the rectal stump is engaged by the end of the handling rod of the surgical stapler, according to an embodiment of the invention;

[0030] - figure 4 is a schematic side view of the head and of the end of the handling rod shown in figure 3, in a condition of mutual engagement and approach, according to an embodiment of the invention;

[0031] - figure 5 is a schematic side view of the head and the cup, in a condition of penetration of the radially protruding formation within the latter (with consequent complete retraction of the suture of the rectal stump within the cup), according to one embodiment of the invention; and

[0032] - figures 6A and 6B are respectively a schematic side view and a cross-sectional view of a head of a surgical stapler, adapted to engage the colic stump and provided with a radially protruding expandable-type formation, according to an alternative embodiment of the invention.

[0033] Detailed description

[0034] Before explaining in detail a plurality of embodiments of the invention, it should be clarified that the invention is not limited in its application to the construction details and the configuration of the components presented in the following description or illustrated in the drawings. The invention is capable of assuming other embodiments and of being implemented or carried out practically in various ways. It should also be understood that the phraseology and terminology have a descriptive purpose and should not be construed as limiting.

[0035] With exemplary reference to the figures, a surgical stapler adapted to mutually suture a rectal stump R and a colic stump C of a patient in a colorectal anastomosis surgery, comprises a handling rod (of which the terminal part is shown, intended to engage the rectal stump R), which includes at one of its ends a loader assembly, which in turn comprises a cup 10 of hollow cylindrical shape, the upper edge of which is adapted to abut against a pre-sutured terminal portion of the rectal stump R, and a sectioning and suturing mechanism, known per se and configured to project beyond said terminal edge of the cup 10 a blade and a plurality of staples, adapted respectively to sever a central portion of the rectal stump R and the colic stump C and to suture to one another the latter.

[0036] The handling rod further comprises a tip 12, adapted to axially protrude beyond said terminal edge of the cup 10 and beyond the terminal suture of the rectal stump R.

[0037] The surgical stapler further comprises a head assembly 14, which includes an enlarged head 16, the lower edge of which is intended to abut against a sutured terminal portion of the colic stump C, and a hollow stem 18, integral with the head 16 and axially protruding therefrom.

[0038] The stem 18 is configured in such a way as to axially engage the tip 12 of the handling rod, which tip 12 is operable so as to cause the stem 18 to translate and axially bring the head 16 closer to the cup 10 of the loader assembly.

[0039] There is also provided a radial formation 20, carried by the stem 18 or the tip 12 and axially spaced from the head 16 in such a way that, during the surgical operation, the terminal suture of the colic stump C is axially contained between the lower edge of the head 16 and said radial formation 20. In other words, the stem 18 or the tip 12 are configured in such a way that, in an assembled condition during the surgical operation, the suture of the colic stump C is or is placeable between the head 16 and the radial formation 20, thereby avoiding overlapping with the latter, or coinciding with it, so as to allow suturing of the colic stump closer (preferably, immediately below) to the head 16, and to sacrifice the smallest possible amount of biological tissue of the colic stump.

[0040] Said radial formation 20 is configured to protrude radially with respect to the stem 18 or the tip 12 and to fit into the cup 10 of the loader assembly when the head 16 is brought closer to the cup 10 of the loader assembly, so as to drag the entire terminal suture of the rectal stump R within said cup 10, without tearing the tissue of said rectal stump R.

[0041] An embodiment of the invention will be described below, with exemplary reference to the figures.

[0042] In particular, figure 1 schematically shows the steps of execution of a colorectal anastomosis, which includes a first step (a) of identifying a portion of the intestine to be removed, a step (b) of creating a rectal stump R by means of a traditional linear surgical stapler, which closes the upper edges of said rectal stump R by applying a linear suture as in step (c), and a step (d) of perforating the rectal stump R by means of a tip 12 extracted through the cup 10 of the handling rod of the stapler.

[0043] A step (e) is then provided for inserting the head 16 of the head assembly 14 of the surgical stapler inside the open colic stump C, the edges of which are stitched and closed around the stem 18 of the head assembly 14 as in step (f), in such a way that the head 16 remains inside the colic stump C.

[0044] Then there is a step (g) of mutual engagement of the tip 12 with the stem 18 and of bringing the head 16 closer to the cup 10, until the two stumps R, C come into mutual contact. Then, according to a step not illustrated, the loader assembly of the handling rod of the surgical stapler is activated, to centrally section the two stumps (so as to create a through hole), simultaneously suturing their edges to each other, as in step (h).

[0045] In particular, the step (g) of bringing the head 16 closer to the cup 10 is carried out by causing the radial formation 20 to penetrate into the cup 10, so as to drag therein the portion of the rectal stump pre-sutured in step (c), as exemplarily illustrated in figure 5. By doing so, the tissue of the rectal stump R will tend to slide along the outer wall and upper edge of the cup 10, penetrating inside the cup 10, until the suture is entirely contained therein, and a flat surface of the rectal stump remains exposed at the top at said edge of the cup 10, with which the end of the colic stump C, dragged by the head 16, can come into contact.

[0046] According to one embodiment, exemplarily illustrated in figures 2 to 5, the radial formation

[0047] 20 comprises a cylindrical portion 21, forming part of the stem 18 of the head assembly 14 or fitted thereon, and one or more fins 22, radially protruding from said cylindrical portion

[0048] 21 and adapted to engage the tissue of the rectal stump R to fold it within the cup 10.

[0049] The fins 22 may for example have a substantially triangular profile and be circumferentially spaced along the outer wall of the cylindrical portion 21 of the radial formation 20.

[0050] According to one embodiment, four fins 22 are provided, symmetrically arranged in pairs on opposite sides of the cylindrical portion 21, in such a way that the smaller angle defined between the fins 22 of each pair is an acute angle.

[0051] The fins 22 are preferably inclined towards the cup 10, having their respective radially outer vertices aligned along a circumference concentric to and axially spaced from the lower edge of the cylindrical portion 21 of the radial formation 20, in the direction of the cup 10.

[0052] According to an alternative embodiment, exemplarily illustrated in figures 6A and 6B, the radial formation 20 comprises a cylindrical portion 21, forming part of the stem 18 of the head assembly 14 or fitted thereon and having one or more through holes, the head assembly 14 or the tip 12 further comprising an inflatable element 24, configured to be radially contained in a non-operative configuration within the cylindrical portion 21 of the radial formation 20 and to expand radially through the holes in said cylindrical portion 21 in such a way as to radially protrude therefrom in an operative condition, said inflatable element 24 being adapted, in the expanded configuration, to engage the suture of the rectal stump R to fold it within the cup 10.

[0053] The inflatable element 24 may comprise a plurality of lobes adapted to protrude radially in a circumferentially spaced manner from the outer wall of the cylindrical portion 21 of the radial formation 20.

[0054] Conveniently, there may be provided insufflation means (not illustrated), in fluid connection with the inflatable element 24, adapted to cause its expansion and / or collapse. For example, a cannula may be provided axially passing along the tip 12 up to a section thereof capable of being fluidly connected with the inflatable element 24, so as to supply or withdraw the inflation fluid thereto / therefrom.

[0055] According to a preferred embodiment, the tip 12 has a pointed end, adapted to penetrate the tissue of the rectal stump R. In this way, when the tip 12 is extracted from the cup 10, it passes through the tissue of the rectal stump R.

[0056] The tip 12 may conveniently be rotatably operable and / or axially extendable / retractable from / into the handling rod through the cup 10 of the loader assembly, so as to drag the head assembly 14 towards said loader assembly, in a condition of engagement between said tip 12 and the stem 18 of said head assembly 14.

[0057] According to a preferred embodiment, the radial formation 20 has a maximum outer diameter between 20 mm and 24 mm, and the cup 10 has an inner diameter between 22 mm and 28 mm. Said maximum outer diameter is preferably to be understood as the diameter of the maximum circumference in which the radially protruding elements of the radial formation 20 are inscribable when in the condition of engaging the pre-sutured portion of the rectal stump R to push it entirely into the cup 10. This condition may be inherently determined by the geometry of the radial formation 20, when the latter has a rigid structure (as for example in the embodiment illustrated in figures 2 to 5), or may occur when the radial formation 20 is in an expanded configuration, if said formation 20 comprises an expandable element (as for example in the embodiment illustrated in figures 6A and 6B).

[0058] According to a preferred embodiment, the radial formation 20 is configured to fit into the cup 10 of the loader assembly for at least 1 / 3 of the axial depth of said cup 10, and more preferably for at least 1 / 2 of the depth of said cup 10.

[0059] Throughout the present description and in the claims, the terms and expressions indicating positions and orientations, such as “axial,” “radial,” or “transverse,” are to be referred to the axis of the cup 10.

[0060] Various aspects and embodiments of a surgical stapler according to the invention have been described. It is understood that each embodiment may be combined with any other embodiment. The invention is also not limited to the described embodiments but may be varied within the scope defined by the appended claims.

Claims

CLAIMS1. Surgical stapler, adapted to suture one another a rectal stump and a colic stump of a patient in a colorectal anastomosis surgery, comprising:- a handling rod, which includes a loader assembly at its one end, comprising- a cup (10) of hollow cylindrical shape, the up-per edge of which is intended to rest against a pre-sutured terminal portion of the rectal stump; and- a sectioning and suturing mechanism, configured to project beyond said terminal edge of the cup (10) a blade and a plurality of staple, designed to sever a central portion of the rectal stump and the colic stump, respectively, and to suture the latter together; the handling rod also including a tip (12), which is designed to protrude axially beyond said terminal edge of the cup (10) and beyond the terminal suture of the rectal stump; the surgical stapler further comprising a head assembly (14), which includes an enlarged head (16), the lower edge of which is intended to rest against a sutured end portion of the colic stump, and a hollow stem (18), integral with the head (16) and protruding axially therefrom, said stem (18) being configured in such a way as to engage axially with the tip (12) of the handling rod, said tip (12) being operable so as to cause the stem (18) to translate and axially bring the head (16) closer to the cup (10) of the loader assembly;characterised in that it comprises a radial formation (20), carried by the stem (18) or tip (12) and axially spaced from the head (16) in such a way that, during surgery, the terminal suture of the colic stump is axially contained between the lower edge of the head (16) and said radial formation (20), said radial formation (20) being configured to protrude radially with respect to the stem (18) or the tip (12) and to fit into the cup (10) of the loader assembly when the head (16) is brought closer to the cup (10) of the loader assembly, in such a way as to drag the entire terminal suture of the rectal stump within said cup (10), without tearing the tissue of said rectal stump.

2. Surgical stapler according to claim 1, wherein the radial formation (20) has a maximum outer diameter of between 20 mm and 24 mm, and the cup (10) has an inner diameter between 22 mm and 28 mm.

3. Surgical stapler according to claim 1 or 2, wherein the radial formation (20) comprises a cylindrical portion (21), forming part of the stem (18) of the head assembly (14) or fitted onto the same, and one or more fins (22), projecting radially from said cylindrical portion (21) and suitable for engaging the tissue of the rectal stump to fold it within the cup (10).

4. Surgical stapler according to claim 3, wherein the fins (22) have a substantially triangular profile and are circumferentially spaced along the outer wall of the cylindrical portion (21) of the radial formation (20).

5. Surgical stapler according to claim 4, wherein the fins (22) are inclined towards the cup (10), the respective radially outer vertices being aligned along a circumference concentric to and axially spaced from the lower edge of the cylindrical portion (21) of the radial formation (20), to-wards the cup (10).

6. Surgical stapler according to claim 1, wherein the radial formation (20) comprises a cylindrical portion (21), forming part of the stem (18) of the head assembly (14) or fitted onto the same and having one or more through holes, the head assembly (14) or the tip (12) further comprising an inflatable element (24), configured to be radially contained in a nonoperative configuration within the cylindrical portion (21) of the radial formation (20) and to radially expand through the holes in said cylindrical portion (21) so as to radially protrude therefrom, said inflatable element (24) being capable, in the expanded configuration, ofengaging the suture of the rectal stump to fold it within the cup (10).

7. Surgical stapler according to claim 6, wherein the inflatable element (24) comprises a plurality of lobes protruding radially in a circumferentially spaced manner from the outer wall of the cylindrical portion (21) of the radial formation (20).

8. Surgical stapler according to any of the preceding claims, wherein the tip (12) has a pointed end, adapted to penetrate the tissue of the rectal stump.

9. Surgical stapler according to any one of the preceding claims, wherein the tip (12) is rotatably operable and / or is axially extendable / retractable from / into the handling rod through the cup (10) of the loader assembly, so as to drive the head assembly (14) towards said loader assembly, in a condition of engagement between said tip (12) and the stem (18) of said head assembly (14).

10. Surgical stapler according to any one of the preceding claims, wherein the radial formation (20) is configured to fit into the cup (10) of the loader assembly for at least 1 / 3 of the axial depth of said cup (10), and more preferably for at least 1 / 2 of the axial depth of said cup (10).

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