SELF-EXPANDABLE SURGICAL IMPLANT FOR CORRECTON OF CONGENITAL DIAPHRAGMATIC HERNIA

Abstract

A self-expandable double-sided surgical implant including a peripheral pocket receiving an expansion ring. The surgical implant may be used for the correction of congenital diaphragmatic hernias.

Description

BACKGROUND AND SUMMARY OF THE DISCLOSURE

The present invention relates generally to surgical implants for repairing tissue openings and, more particularly, to such surgical implants for the thoracoscopic correction of congenital diaphragmatic hernias (CDH). Thorascopic repair typically involves primary or patch closure of the defect. Such surgical implants and associated methods are of particular interest to pediatric surgeons. Conventional approaches can present recurrences and technical difficulties due to the suture tension on large defects. The use of patches requires demanding thoracoscopic skills, and therefore primary closure with tight sutures is often pursued, which increases the risk of recurrence.

Embryologically, the diaphragm is formed between the eighth and tenth week of gestation, which results in the separation of the abdominal cavity and the thoracic compartment. For a congenital diaphragmatic hernia (CDH) to occur, there must be a disorder in the embryonic development of this muscle and tendon, the location and size being variable. As a consequence of this fusion defect, part of the abdominal content passes into the thorax.

Congenital diaphragmatic hernia (CDH) is a defect that occurs in 1 in 3,000 live births, of which approximately 60% occur in isolation without other congenital anomalies. As is known, congenital diaphragmatic hernias (CDH) are of two main types: Bochdalek hernias and Morgagni hernias. The most frequent diaphragmatic hernia is the Bochdalek hernia (95% of cases). A Bochdalek hernia is a congenital abnormality in which an opening exists in the infant's diaphragm, allowing normally intra-abdominal organs (particularly the stomach and intestines) to protrude into the thoracic compartment. It consists of a posterolateral defect, more frequent on the left side. Morgagni hernia, ventral and parasternal defect, is more prevalent on the right side. A hiatal hernia occurs when the gastroesophageal junction travels to the chest through the esophageal hiatus, being more frequent in adults.

The size of the diaphragmatic defect is variable and decisive in prognosis and mortality, since it clearly correlates with the degree of severity of pulmonary hypoplasia. FIG. 1 shows the location of different diaphragmatic hernias, including Bochdalek hernia 2, Morgagni hernia 4, and hiatal hernia 6. FIG. 2 illustrates different size Bochdalek hernias, such as small defects type A, intermediate type B, large type C, and at the end of the spectrum, the complete agenesis of the hemidiaphragm in type D. Illustratively, the size of the defect in Bochdalek hernias include type A of less than 3 cm, type B and C of intermediate size, and up to type D with agenesis of the diaphragmatic leaf.

The present disclosure relates to a system and associated methods for thoracoscopic surgery in newborns including a novel surgical implant or patch that facilitates the suturing process thereby minimizing the risk of injury of the underlying viscera. The illustrative surgical implant has characteristics of self-expandability and a traction central suture to stabilize the implant when it is located in the abdominal side of the patient. The surgical implant illustratively includes a folding pocket receiving an elastic ring that facilitates suturing a mesh to the diaphragmatic muscle when covering the abdominal viscera.

According to an illustrative embodiment of the present disclosure, surgical implant for repairing a tissue opening includes a body having a proximal member, a distal member coupled to the proximal member, and a peripheral pocket. The peripheral pocket is defined by a reentrant outer edge of the distal member extending around an outer edge of the proximal member. A resilient ring is received within the peripheral pocket and is configured to apply tension to the body.

According to a further illustrative embodiment of the present disclosure, a method of forming a surgical implant includes the steps of providing a thoracic member having a proximal surface and a distal surface, providing an abdominal member having a proximal surface and a distal surface, and positioning the distal surface of the thoracic member adjacent to the proximal surface of the abdominal member. The method further includes the steps of folding an outer rim of one of the abdominal member and the thoracic member over an outer edge of the other of the thoracic member and the abdominal member to define a reentrant lip, and securing the thoracic member to the abdominal member by the reentrant lip. The method further includes the steps of defining a peripheral pocket with the reentrant lip, and inserting a support ring within the peripheral pocket.

According to another illustrative embodiment of the present disclosure, a method of attaching a surgical implant to a diaphragmatic hernia includes the steps of providing a surgical implant including a body having a proximal member, a distal member coupled to the proximal member, a peripheral pocket defined by a reentrant outer rim of the distal member extending around an outer edge of the proximal member, and a support ring received within the peripheral pocket and configured to apply tension to the body, and folding the surgical implant. The method further includes the steps of passing the folded surgical implant from a thoracic compartment, through a diaphragmatic rim, and into the abdominal cavity, and expanding the support ring to apply tension to the body of the surgical implant. The method further includes the steps of pulling a central suture coupled to the body to stabilize the surgical implant against the diaphragmatic rim, and suturing the body of the surgical implant to the diaphragmatic rim.

Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawings particularly refers to the accompanying figures in which:

FIG. 1 is a cross-sectional view of different illustrative diaphragmatic hernias;

FIG. 2 is a cross-sectional view of different illustrative Bochdalek type congenital diaphragmatic hernias (CDH);

FIG. 3 is a cross-sectional view of a surgical implant according to an illustrative embodiment of the present disclosure placed in a diaphragmatic opening;

FIG. 4 is an exploded perspective view of a thoracic member of the illustrative surgical implant of FIG. 3;

FIG. 5 is a perspective view of the thoracic member of FIG. 4;

FIG. 6 is an exploded perspective view of an abdominal member of the illustrative surgical implant of FIG. 3;

FIG. 7 is a perspective view of the abdominal member of FIG. 6;

FIG. 8 is an exploded perspective view of the thoracic member and the abdominal member of the illustrative surgical implant of FIG. 3;

FIGS. 9A-9C are cross-sectional views, in partial schematic, showing assembly steps of the illustrative surgical implant of FIG. 3;

FIGS. 10A and 10B are perspective views showing the support ring inserted within the peripheral pocket of the illustrative surgical implant of FIG. 3;

FIG. 11 is a perspective view of the illustrative surgical implant of FIG. 3, including a central placement suture;

FIG. 12 is a perspective view showing the central suture providing traction for stability against a diaphragmatic rim;

FIG. 13 is a perspective view of the thoracic side of the illustrative surgical implant of FIG. 3 in situ;

FIG. 14 is a perspective view of the abdominal side of the illustrative surgical implant of FIG. 3 in situ;

FIG. 15A is a graph showing surgical time for representative surgical implant placements;

FIG. 15B is a heat map showing surgical time for representative surgical implant placements;

FIG. 16 is a graph showing mean of good quality stitches per representative surgical implant, with wiskers illustrating standard deviation;

FIG. 17A is a graph showing the level of difficulty for representative surgical implant placements; and

FIG. 17B is a graph of the Likert scale for representative surgical implant placements.

DETAILED DESCRIPTION OF THE DRAWINGS

For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, which are described herein. The embodiments disclosed herein are not intended to be exhaustive or to limit the invention to the precise form disclosed. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. Therefore, no limitation of the scope of the claimed invention is thereby intended. The present invention includes any alterations and further modifications of the illustrated devices and described methods and further applications of principles in the invention which would normally occur to one skilled in the art to which the invention relates.

With reference to FIG. 3, an illustrative surgical implant 10 is configured to be supported by a diaphragm 12 intermediate a thoracic compartment 14 and an abdominal cavity 16. More particularly, the implant 10 is supported within a defect, illustratively a diaphragmatic opening 18 defined by a diaphragmatic rim 20. In the following detailed description, the surgical implant 10 may also be referred to as a patch or self-expandable mesh (SeM).

With reference to FIGS. 3-10B, the surgical implant 10 illustratively includes a body 22 including a proximal member 24 coupled to a distal member 26. A reentrant outer lip 28 of the distal member 26 defines a peripheral pocket 30 receiving a support ring 32 thereby expanding the surgical implant 10.

With reference to FIGS. 4 and 5, the proximal member 24 is illustratively a circular thoracic member 34 including a first or proximal mesh layer 36 coupled to a second or distal mesh layer 38. An adhesive layer 40 illustratively couples the first mesh layer 36 to the second mesh layer 38. The first mesh layer 36 and the second mesh layer 38 are illustratively circular disks having a proximal outer diameter (PD₁). In an illustrative embodiment, the proximal outer diameter (PD₁) is approximately 6 cm.

The proximal member 24 is illustratively formed of a mesh material such as a synthetic biocompatible material. More particularly, each mesh layer 36 and 38 of the proximal member 24 are illustratively formed of a stretchable nonwoven polyester with a hypoallergenic polyacrylate adhesive surface 42 and 44, respectively. Releasable liners 43 and 45 may cover the adhesive surfaces 42 and 44, respectively, until assembled into the proximal member 24. In one illustrative embodiment, the mesh layers 36 and 38 may be formed from Fixomul® Stretch dressing material (Ref. 70022-00 available from BSN Medical GmbH of Hamburg, Germany). The proximal member 24 may be adapted to any suitable material, synthetic or biocompatible. For example, a polytetrafluoroethylene (ePTFE) material may be used for the proximal member 24 (such as Dualmesh® Biomaterial, available from W.L. Gore & Associates of Flagstaff, Arizona).

During assembly of the thoracic member 34, two circular mesh layers 36 and 38 of substantially equal outer diameters (PD₁) (illustratively, 6 cm each) are positioned with their adhesive surfaces 42 and 44 facing one another following removal of the liners 43 and 45. The adhesive surfaces 42 and 44 are then brought into contact with each other such that the surfaces 42 and 44 together define the adhesive layer 40 (FIG. 4) for securing the first mesh layer 36 with the second mesh layer 38.

With reference to FIGS. 6 and 7, the distal member 26 is illustratively a circular abdominal member 47 including a first or proximal mesh layer 46 coupled to a second or distal mesh layer 48. An adhesive layer 50 illustratively couples the first mesh layer 46 and the second mesh layer 48. The first mesh layer 46 illustratively has a first distal outer diameter (DD₁), and the second mesh layer 48 illustratively has a second distal outer diameter (DD₂). Illustratively, the second distal outer diameter (DD₂) is greater than the first distal outer diameter (DD₁), thereby defining an outer rim 60. In an illustrative embodiment, the first distal outer diameter (DD₁) is approximately 6 cm, while the second distal outer diameter (DD₂) is approximately 8 cm. As such, the outer rim 60 has a width (W) of approximately 1 cm.

The distal member 26 is illustratively formed of a mesh material such as a synthetic biocompatible material. More particularly, each mesh layer 46 and 48 of the distal member 26 are illustratively formed of a stretchable nonwoven polyester with a hypoallergenic polyacrylate adhesive surface 52 and 54, respectively. Releasable liners 56 and 58 may cover the adhesive surfaces 52 and 54, respectively, until assembled into the distal member 26. In one illustrative embodiment, the mesh layers 46 and 48 may be formed from Fixomul® Stretch dressing material (Ref. 70022-00 available from BSN Medical GmbH of Hamburg, Germany).

The distal member 26 may be formed of any kind of synthetic or biocompatible material, if it complies with the functional features including sufficient resiliency to be compressed and subsequently expanded by the support ring 32 received within the pocket 30. For example, a polytetrafluoroethylene (ePTFE) material may be used for the distal member 26 (such as Dualmesh® Biomaterial, available from W.L. Gore & Associates of Flagstaff, Arizona).

During assembly of the distal member 26 as shown in FIGS. 8-10B, two circular mesh layers 46 and 48 of different outer diameters (DD₁) and (DD₂)(illustratively, 6 cm and 8 cm, respectively) are positioned with their adhesive surfaces 52 and 54 facing one another following removal of the liners 56 and 58. The adhesive surfaces 52 and 54 are then brought into contact with each other such that the surfaces 52 and 54 together define the adhesive layer 50 (FIGS. 6 and 7) for securing the first mesh layer 46 with the second mesh layer 48.

As noted above, the surgical implant 10 can be formed of a wide variety of synthetic biocompatible materials, if it complies with the required functional features. For the creation of the proximal member 24, two circular mesh layers 36 and 38 of 6 cm outer diameter are pasted on top of each other, with their adhesive surfaces 42 and 44 facing one another (FIGS. 4 and 5). For the distal member 26, two circular mesh layers 46 and 48 of 6 and 8 cm outer diameters are pasted on top of each other as described for the proximal member 24 (FIGS. 6 and 7).

Next, the proximal member 24 and the distal member 26 are approached to each other (FIG. 8). The 2 cm difference between the between the two members 24 and 26 define the outer rim 60 having a width (W) of 1 cm. The outer rim 60 is folded over an outer edge 62 of the proximal member 24 to define the reentrant outer lip 28. The adhesive surface 52 on the mesh layer 48 of the distal member 26 secures the reentrant outer lip 28 to the mesh layer 36 of the proximal member 24 to create the pocket 30 (FIGS. 9A-9C). Afterwards, a center 66 of the proximal member 24 is cut away to open access to the pocket 30 (FIG. 9B) where the support ring 32 is received (FIGS. 9C-10B).

The support ring 32 is illustratively a semi-rigid annular member having a shape memory, so the surgical implant 10 will remain expanded (FIG. 9C), illustratively to an outer diameter equal to DD₁ (e.g., approximately 6 cm). Illustratively, the support ring 32 may be formed of a resilient polymer, such as an elastomer and/or silicone. In one illustrative embodiment, the support ring 32 is formed from the stent positioner of a pigtail ureteral stent (Ref. 036308 available from Cook Medical of Bloomington, Indiana), by joining the opposing ends with n-butyl-2-cyanoacrylate adhesive (Ref. 1050052 available from B Braun Histoacryl® of Bethlehem, Pennsylvania).

A central placement suture 70 is illustratively secured in the center of the distal member 26 of the surgical implant 10 that allows traction from the thoracic compartment 14 against the diaphragmatic rim 20, providing in situ stability for the suturing process (FIGS. 11-14). Illustratively, the central placement suture 70 is a 20 cm 2/0 silk suture.

An illustrative method of attaching the surgical implant 10 to a diaphragmatic hernia 18 may utilize known minimally invasive surgical procedures, such as videotorascopic techniques. Illustratively, the method includes an initial step of compressing, illustratively folding, the surgical implant 10. More particularly, the surgical implant 10 is collapsed or rolled for passing from the thoracic compartment 14, through the opening 18 defined by the diaphragmatic rim 20, and into the abdominal cavity 16. A conventional surgical instrument, such as a trocar, may be used to position the surgical implant 10. More particularly, after having reduced the herniated intestine, the surgical implant 10 is moved to the abdominal cavity 16 through the defect 18 with the support ring 32 providing for expansion of the body 22.

The surgical implant 10 is configured to self-expand as a result of the support ring 32 received within the pocket 30. Once the support ring 32 is expanded in the abdominal side of the defect 18, the body 22 remains deployed in close contact with the diaphragmatic rim 20 by positive pressure of the abdominal cavity 16 and the negative pressure of the thoracic compartment 14 (the pressure differential being represented by arrows 72 in FIG. 3).

Once the surgical implant 10 is adequately positioned within the abdominal cavity 16, the central placement suture 70 is illustratively pulled axially toward the thoracic compartment 14 through a surgical instrument (e.g., a trocar) to assist in keeping the surgical implant 10 in place during the suturing process. The surgical implant 10 is illustrated as being positioned below the diaphragmatic rim 20 supported on the edges of the defect 18 and enhanced by external traction of the central placement suture 70.

Conventional sutures or stitches 74 are illustratively used to secure the body 22 of the surgical implant 10 to the diaphragm 12. More particularly, stitches 74 may secure the pocket 30 and/or support ring 32 to the diaphragmatic rim 20. The suturing can be performed using intracorporeal or extracorporeal knot-tying technique. Illustratively, at least 8 equidistant interrupted stitches 74 with at least 3 throws per knot are provided to secure the surgical implant 10. It should be appreciated that the number of stitches 74 can vary with the size of the surgical implant 10 and/or the defect 18. After the suturing process is complete, the central placement suture 70 can be cut away. It should be appreciated that the support ring 32 may remain within the pocket 30 following the suturing step, or be removed from the pocket 30 depending upon the type and placement of the stitches 74 relative to the surgical implant 10.

The surgical implant 10 isolates and protects all the abdominal viscera. The proximity of the free edge of the pocket 30 in the thoracic side to the diaphragmatic margins allows an easy and precise suture with continuous or interrupted stitches 74. The distal mesh 26 forges a pocket 30 around the ring 32, embracing it. The margins of that pocket 30 in his thoracic side will be facing the diaphragmatic rim 20 to allow an easy and precise suture. Eventually, the support ring 32 will give a safe surface below every stitch to avoid inadvertent injuries of the underlying viscera. Finally, the surgical implant 10 is essentially stable due to a traction central placement suture 70 that keeps the implant 10 in close contact with the diaphragmatic rim 20 (FIG. 3).

An inanimate model for the thoracoscopic repair of congenital diaphragmatic hernia (CDH) was used to recreate the surgical technique. In the following description, different variables are compared for both the surgical implant 10 of the present disclosure (identified as self-expanding mesh (SeM)) and known patches (identified as conventional mesh (CM)). Illustratively, nine CDH cases were repaired with each type of mesh (n=18 CDH cases) in an inanimate model of the disease by experiences pediatric surgeons.

Quantitative and qualitative data results are expressed as mean+/−standard deviation (SD). For the comparison of not normal distributed groups, differences between means were compared using Mann-Whitney test. Statistical analysis and figures were made using the Prism 8 package (available from Graphpad Software Inc. of La Jolla, California), and p value<0.05 was considered statistically significant.

With reference to FIGS. 15A and 15B, the variable of surgical time for placement of surgical implant is assessed in minutes from its introduction through the port of the surgical instrument until its complete suture. FIG. 15A shows the average surgical time taken for each mesh with distribution and standard deviation for nine placements. The surgical time taken for SeM placement was significantly lower (29.3±5.6 minutes) compared to 33.2±5.9 minutes for the CM (*p≤0.05, Mann-Whitney). The differences in time used to place and suture the different implants can be observed in the heatmap of FIG. 15B.

With reference to FIG. 16, the variable of quality of the suturing process is assessed by quantifying the number of good quality knots (with at least three throws per knot, tight enough to the implant and the diaphragmatic rim), and the occurrence of an adverse event during the suturing such as bowel injury, diaphragmatic rips or large gaps between knots. FIG. 16 shows the mean of good quality stitches/knots per surgical implant with wiskers showing standard deviation. The number of good quality stitches/knots per mesh was in average 7.9±0.3 for SeM and 7.3±1 for CM, considering that the number of stitches placed per mesh was 8. The percentage of surgeries in which all the knots were good quality (scoring 8 out of 8) were 55.6% for CM and 88.8% for SeM.

The adverse events occurring during the suturing process were 1 for the SeM (diaphragmatic rip n=1) and 7 for the CM (bowel injury n=2, diaphragmatic rip n=2, and large gaps between knots n=3).

FIGS. 17A and 17B show the assessment of the level of difficulty of the surgical procedure using a five-point Likert scale (Very Easy, Easy, Intermediate, Difficult and Very Difficult). FIG. 17A is a Violin plot for each surgical implant's Likert scale and data distribution. The level of difficulty reported for each procedure using the five-points Likert scale were 4.8±0.3 and 4.0±0.5 for the SeM and CM respectively (**p≤0.001, Mann-Whitney) (FIG. 17A). FIG. 17B shows the Likert scale for each surgical implant. SeM placement was reported to be Very easy (n=8) and Easy (n=1), and for the CM was Very easy (n=1), Easy (n=7) and Intermediate (n=1) (FIG. 17B).

In summary, nine cases of CDH were repaired with each type of implant (SeM and CM). The total duration of the procedure was shorter when using the self-expandable mesh (SeM) 10 when compared to the conventional mesh (CM)(p≤0.05). The level of difficulty was reported to be lower for the self-expandable mesh (SeM) 10 (p≤0.001). The number of good quality knots was higher and adverse events were less common for the self-expandable mesh (SeM) 10, with no visceral injury observed.

The surgical implant of the present disclosure in the form of a stabilizing self-expanding mesh (SeM) offers a safe and ergonomic performance for the thoracoscopic repair of congenital diaphragmatic hernia (CDH) facilitating the surgical technique, especially for large defects where the primary closure can lead to recurrences. The main advantages of this surgical implant are that it keeps the viscera isolated into the abdomen while offering a flap on the thoracic side for suturing in a comfortable and practical fashion, minimizing the risk of visceral injury and saving surgical time that is especially precious in patients with pulmonary hypertension. The quality of the suturing process is superior with this novel surgical implant system and although in this surgical model is not possible to follow-up for the analysis of long term results, it would be interesting to study in animal models if these immediate benefits observed in the surgery, have some impact in the recurrence of the disease. The surgical implant of the present disclosure is synthetic but is customizable and could be made with biological materials as well.

This novel mesh has been created to facilitates the thoracoscopic repair of the neonatal CDH. It has characteristics of self-expandability due to the presence of a semi-rigid ring. Once the ring is expanded in the abdominal side of the defect, it remains deployed in close contact with the diaphragmatic rim facilitated by the positive pressure of the abdominal cavity and the negative pressure of the thoracic compartment. The mesh itself will isolate and protect the viscera in the abdominal compartment, minimizing the risk of injury.

While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will be readily apparent to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative system and method, and illustrated examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the invention.

Claims

1. A method of forming a surgical implant including the steps of: providing a thoracic member including a proximal surface and a distal surface;providing an abdominal member including a proximal surface and a distal surface;positioning the distal surface of the thoracic member adjacent to the proximal surface of the abdominal member;folding an outer edge of one of the abdominal member and the thoracic member over an outer edge of the other of the thoracic member and the abdominal member to define a reentrant lip;securing the thoracic member to the abdominal member by the reentrant lip;defining a peripheral pocket with the reentrant lip; andinserting a support ring within the peripheral pocket.

2. The method of claim 1, further comprising the step of applying tension to the abdominal member by the support ring.

3. The method of claim 1, wherein the step of defining a peripheral pocket includes cutting a center portion of the thoracic member.

4. The method of claim 1, wherein: the thoracic member defines a proximal member and includes a first mesh layer and a second mesh layer coupled to the first mesh layer;the abdominal member defines distal member and includes a first mesh layer and a second mesh layer coupled to the first mesh layer; andthe outer diameter of the thoracic member is less than the outer diameter of the abdominal member.

5. The method of claim 1, wherein the thoracic member is a mesh formed of a stretchable nonwoven polyester or polytetrafluoroethylene material, and the abdominal member is a mesh formed of a stretchable nonwoven or polyester polytetrafluoroethylene material.

6. The method of claim 5, wherein the support ring is formed of a resilient polymer.

7. The method of claim 1, further comprising the step of securing a placement suture proximate the center of the abdominal member.

8. A method of attaching a surgical implant to a diaphragmatic hernia comprising the steps of: providing a surgical implant including a body having a proximal member, a distal member coupled to the proximal member, a peripheral pocket defined by a reentrant outer lip of the distal member extending around an outer edge of the proximal member, and a support ring received within the peripheral pocket and configured to apply tension to the body;folding the surgical implant;passing the folded surgical implant from a thoracic compartment, through a diaphragmatic rim, and into abdominal cavity;expanding the support ring to apply tension to the body of the surgical implant;pulling a central suture coupled to the body to stabilize the surgical implant against the diaphragmatic rim; andsuturing the body of the surgical implant to the diaphragmatic rim.

9. The method of claim 8, further comprising the step of cutting the central suture following the suturing step.

10. The method of claim 8, wherein the body is a mesh formed of a stretchable nonwoven polyester or polytetrafluoroethylene material.

11. The method of claim 8, wherein the support ring is formed of a resilient polymer.

12. The method of claim 8, wherein the folding step comprises rolling the surgical implant for insertion through a trocar.