Staple reinforcement for surgical stapler

Abstract

The present invention aims to provide a staple reinforcement for a surgical stapler that can be used in surgical staplers of various sizes, is easily passed through ports, and is less likely to shift during operation of the surgical stapler. Provided is a staple reinforcement for a surgical stapler, including a fabric layer containing a bioabsorbable material and a sponge layer containing a water-soluble polymer, the fabric layer and the sponge layer being integrally laminated.

Claims

1. A staple reinforcement for a surgical stapler, comprising: a fabric layer containing a bioabsorbable material; and a sponge layer consisting of at least one water-soluble polymer selected from the group consisting of hydroxypropyl methylcellulose and sodium alginate, the fabric layer and the sponge layer being integrally laminated, the sponge layer being on a side that is configured to adhere to a surface of the surgical stapler where the staple reinforcement is attached to the surgical stapler, and the sponge layer being a freeze-dried product.

2. The staple reinforcement for a surgical stapler according to claim 1, wherein the bioabsorbable material is polyglycolic acid, polylactic acid, or a copolymer of lactic acid and caprolactone.

3. The staple reinforcement for a surgical stapler according to claim 1, wherein the sponge layer has a thickness of 0.5 mm or more and 10 mm or less.

4. The staple reinforcement for a surgical stapler according to claim 1, which has an adhesion strength of 1.5 N/cm.sup.2 or higher when attached to the surgical stapler.

5. The staple reinforcement for a surgical stapler according to claim 1, wherein the sponge layer is an adhesive layer that is configured to adhere directly to a surface of the surgical stapler when the staple reinforcement is attached to the surgical stapler.

6. The staple reinforcement for a surgical stapler according to claim 1, wherein the water-soluble polymer in a 2% concentration aqueous solution has a viscosity of 1 mPa.Math.s or higher and 500 mPa.Math.s or lower.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 schematically illustrates exemplary conventional staple reinforcements for a surgical stapler.

(2) FIG. 2 schematically illustrates exemplary staple reinforcements for a surgical stapler of the present invention.

DESCRIPTION OF EMBODIMENTS

(3) Embodiments of the present invention are described in more detail below. The present invention, however, should not be limited to these embodiments.

Example 1

(4) (1) Production of staple reinforcement for surgical stapler

(5) Distilled water was added to hydroxypropyl methylcellulose (HPMC) (viscosity grade 6: AN6, 2% solution viscosity: 5.1 mPa.Math.s, produced by Mitsubishi-Chemical Foods Corporation) to prepare an 8% by weight HPMC aqueous solution. Then, 10 g of the HPMC aqueous solution was added to a Φ 100 mm petri dish. Next, a sheet-form polyglycolic acid (PGA) nonwoven fabric cut into Φ 100 mm as a fabric layer was floated on the HPMC aqueous solution in the petri dish. After confirming that the HPMC aqueous solution permeated the sheet-form nonwoven fabric, the petri dish was put in a freezer at −80° C. for 15 minutes, whereby the HPMC aqueous solution was frozen. Thereafter, the frozen HPMC aqueous solution was dried by a vacuum freeze dryer to form a HPMC sponge layer (adhesive layer) on the nonwoven fabric, whereby a staple reinforcement for a surgical stapler was prepared. For the obtained staple reinforcement for a surgical stapler, the thickness of the sponge layer was measured by averaging thicknesses measured using a dial indicator (SMD-565J-L, produced by Teclock Co., Ltd.) at intervals of one site/cm.sup.2. The thickness and weight of the sponge layer were also measured, and the density was calculated. Table 1 shows the results.

(6) (2) Measurement of Adhesion Strength

(7) The reinforcement was cut into a size of 8 mm wide×40 mm long. Only a length of 10 mm was attached to a working surface (anvil side) of a surgical stapler (Endopath Stapler ECHELON FLEX 60, produced by Ethicon, Inc.) presoaked with saline, and pressed for three minutes so that the reinforcement was adhered to the working surface. Subsequently, the handle of the surgical stapler was mounted on the lower chuck of a tensile tester (Autograph Precision Universal Tester AG-X Plus, produced by Shimadzu Corporation), and the end of the reinforcement protruding from the surgical stapler was mounted on the upper chuck of the tensile tester. Thereafter, a tensile test was performed at a pulling speed of 100 mm/min, and the maximum load at which shifting occurred was defined as the adhesion strength. Table 1 shows the results.

Examples 2 to 5

(8) A staple reinforcement for a surgical stapler was obtained as in Example 1 except that the amount of HPMC aqueous solution added to the petri dish was as shown in Table 1. The thickness and density of the sponge layer and the adhesion strength were measured.

Comparative Example 1

(9) Distilled water was added to hydroxypropyl methylcellulose (HPMC) (viscosity grade 6: AN6, 2% solution viscosity: 5.1 mPa.Math.s, produced by Mitsubishi-Chemical Foods Corporation) to prepare an 8% by weight HPMC aqueous solution. Then, 15 g of the HPMC aqueous solution was added to a Φ 100 mm petri dish. Next, a sheet-form polyglycolic acid (PGA) nonwoven fabric cut into Φ 100 mm as a fabric layer was floated on the HPMC aqueous solution in the petri dish. After confirming that the HPMC aqueous solution permeated the sheet-form nonwoven fabric, the petri dish was put in a dryer at 90° C. for 60 minutes to form a HPMC film layer (adhesive layer) on the nonwoven fabric, whereby a staple reinforcement for a surgical stapler was prepared. For the obtained staple reinforcement for a surgical stapler, the thickness and weight of the film layer was measured, and the density was calculated. Table 1 shows the results.

Example 6

(10) Distilled water was added to hydroxypropyl methylcellulose (HPMC) (viscosity grade 50: AN50, 2% solution viscosity: 37 mPa.Math.s, produced by Mitsubishi-Chemical Foods Corporation) to prepare a 6% by weight HPMC aqueous solution. Then, 10 g of the HPMC aqueous solution was added to a Φ 100 mm petri dish. Next, a sheet-form polyglycolic acid (PGA) nonwoven fabric cut into Φ 100 mm as a fabric layer was floated on the HPMC aqueous solution in the petri dish. After confirming that the HPMC aqueous solution permeated the sheet-form nonwoven fabric, the petri dish was put in a freezer at −80° C. for 15 minutes, whereby the HPMC aqueous solution was frozen. Thereafter, the frozen HPMC aqueous solution was dried in a vacuum freeze dryer to form a HPMC sponge layer (adhesive layer) on the nonwoven fabric, whereby a staple reinforcement for a surgical stapler was prepared. For the obtained staple reinforcement for a surgical stapler, the thickness of the sponge layer was measured as in Example 1. The thickness and weight of the sponge layer were also measured, and the density was calculated. Table 1 shows the results.

Examples 7 to 10

(11) A staple reinforcement for a surgical stapler was obtained as in Example 6 except that the amount of HPMC aqueous solution added to the petri dish was as shown in Table 1. The thickness and density of the sponge layer and the adhesion strength were measured.

Comparative Example 2

(12) Distilled water was added to hydroxypropyl methylcellulose (HPMC) (viscosity grade 50: AN50, 2% solution viscosity: 37 mPa.Math.s, produced by Mitsubishi-Chemical Foods Corporation) to prepare a 5% by weight HPMC aqueous solution. Then, 15 g of the HPMC aqueous solution was added to a Φ 100 mm petri dish. Thereafter, a sheet-form polyglycolic acid (PGA) nonwoven fabric cut into Φ 100 mm as a fabric layer was floated on the HPMC aqueous solution in the petri dish. After confirming that the HPMC aqueous solution permeated the sheet-form nonwoven fabric, the petri dish was put in a dryer at 90° C. for 60 minutes to form a HPMC film layer (adhesive layer) on the nonwoven fabric, whereby a staple reinforcement for a surgical stapler was prepared. For the obtained staple reinforcement for a surgical stapler, the thickness and weight of the film layer was measured, and the density was calculated. Table 1 shows the results.

Example 11

(13) Distilled water was added to pullulan (Japanese Pharmacopoeia pullulan, 2% solution viscosity: 3.7 mPa.Math.s, produced by Hayashibara Co., Ltd.) to prepare a 10% by weight pullulan aqueous solution. Then, 20 g of the pullulan aqueous solution was added to a Φ 100 mm petri dish. Next, a sheet-form PGA nonwoven fabric cut into Φ 100 mm as a fabric layer was floated on the pullulan aqueous solution in the petri dish. After confirming that the pullulan aqueous solution permeated the sheet-form nonwoven fabric, the petri dish was put in a freezer at −80° C. for 15 minutes, whereby pullulan aqueous solution was frozen. Thereafter, the frozen pullulan aqueous solution was dried in a vacuum freeze dryer to form a pullulan sponge layer (adhesive layer) on the nonwoven fabric, whereby a staple reinforcement for a surgical stapler was prepared. For the obtained staple reinforcement for a surgical stapler, the thickness and density of the sponge layer and the adhesion strength were measured as in Example 1. Table 1 shows the results.

Examples 12 and 13

(14) A staple reinforcement for a surgical stapler was obtained as in Example 11 except that the amount of pullulan aqueous solution added to the petri dish was as shown in Table 1. The thickness and density of the sponge layer and the adhesion strength were measured.

Example 14

(15) Distilled water was added to sodium alginate (low viscosity grade: IL-2, 2% solution viscosity: 63 mPa.Math.s, produced by Kimica Corporation) to prepare a 10% by weight sodium alginate aqueous solution. Then, 20 g of the sodium alginate aqueous solution was added to a Φ 100 mm petri dish. Next, a sheet-form PGA nonwoven fabric cut into Φ 100 mm as a fabric layer was floated on the sodium alginate aqueous solution in the petri dish. After confirming that the sodium alginate aqueous solution permeated the sheet-form nonwoven fabric, the petri dish was put in a freezer at −80° C. for 15 minutes, whereby sodium alginate aqueous solution was frozen. Thereafter, the frozen sodium alginate aqueous solution was dried in a vacuum freeze dryer to form a sodium alginate sponge layer (adhesive layer) on the nonwoven fabric, whereby a staple reinforcement for a surgical stapler was prepared. For the obtained staple reinforcement for a surgical stapler, the thickness and density of the sponge layer and the adhesion strength were measured as in Example 1. Table 1 shows the results.

Example 15

(16) A staple reinforcement for a surgical stapler was obtained as in Example 14 except that the amount of sodium alginate aqueous solution added to the petri dish was as shown in Table 1. The thickness and density of the sponge layer and the adhesion strength were measured.

Example 16

(17) Distilled water was added to gelatin (MediGelatin HMG-BP, 2% solution viscosity: 2.0 mPa.Math.s, produced by Nippi, Inc.) to prepare a 5% by weight gelatin aqueous solution. Then, 15 g of the gelatin aqueous solution was added to a Φ100 mm petri dish. Next, a sheet-form PGA nonwoven fabric cut into Φ100 mm as a fabric layer was floated on the gelatin aqueous solution in the petri dish. After confirming that the gelatin aqueous solution permeated the sheet-form nonwoven fabric, the petri dish was put in a freezer at −80° C. for 15 minutes, whereby gelatin aqueous solution was frozen. Thereafter, the frozen gelatin aqueous solution was dried in a vacuum freeze dryer to form a gelatin sponge layer (adhesive layer) on the nonwoven fabric, whereby a staple reinforcement for a surgical stapler was prepared. For the obtained staple reinforcement for a surgical stapler, the thickness and density of the sponge layer and the adhesion strength were measured as in Example 1. Table 1 shows the results.

Examples 17 to 19

(18) A staple reinforcement for a surgical stapler was obtained as in Example 16 except that the amount of gelatin aqueous solution added to the petri dish was as shown in Table 1. The thickness and density of the sponge layer and the adhesion strength were measured.

(19) <Evaluation>

(20) The staple reinforcements for a surgical stapler obtained in the examples and the comparative examples were evaluated for the following items. Table 1 shows the results.

(21) (Evaluation of Attachability)

(22) The obtained staple reinforcement for a surgical stapler was cut into a piece of 10 mm wide×60 mm long and a piece of 8 mm wide×60 mm long and attached to the working surfaces (cartridge side and anvil side) of a surgical stapler (Endopath Stapler ECHELON FLEX 60 produced by Ethicon, Inc., diameter: 12 mm) presoaked with saline, such that the sponge layers contacted the surgical stapler. The attachability was evaluated as “Good” when the reinforcement at this time was easily adhered to the working surfaces of the stapler, and “Poor” when the reinforcement was not easily adhered to the working surfaces.

(23) (Evaluation of Ease of Passing Through Port)

(24) The obtained staple reinforcement for a surgical stapler was cut into a piece of 10 mm wide×60 mm long and a piece of 8 mm wide×60 mm long and attached to the working surfaces (cartridge side and anvil side) of a surgical stapler (Endopath Stapler ECHELON FLEX 60 produced by Ethicon, Inc., diameter: 12 mm) presoaked with saline, such that the sponge layers contacted the surgical stapler. The surgical stapler with the staple reinforcement for a surgical stapler attached thereto was then passed through a ϕ 12 mm port. The ease of passing through a port was evaluated as “Good” when the reinforcement at this time did not get caught on the port or separated from the device, and “Poor” when the reinforcement got caught on the port or separated from the device. The evaluation was not performed in Comparative Examples 1 and 2 because the reinforcements could not be mounted on the device.

(25) (Evaluation of Shift Resistance)

(26) The obtained staple reinforcement for a surgical stapler was cut into a piece of 10 mm wide×60 mm long and a piece of 8 mm wide×60 mm long and attached to the working surfaces (cartridge side and anvil side) of a surgical stapler (Endopath Stapler ECHELON FLEX 60 produced by Ethicon, Inc.) presoaked with saline, such that the sponge layers contacted the surgical stapler. Thereafter, a porcine lung was held with the surgical stapler with the staple reinforcement for a surgical stapler attached thereto, and pulled from right to left and up and down. The shift resistance was evaluated as “Good” when the reinforcement at this time did not shift, “Fair” when the reinforcement slightly shifted but the shifting was within a range that does not cause trouble in actual use, and “Poor” when the reinforcement greatly shifted. The evaluation was not performed in Comparative Examples 1 and 2 because the reinforcements could not be mounted on the device.

(27) (Evaluation of Fire Cutting Properties)

(28) A porcine lung was held with the surgical stapler with the staple reinforcement for a surgical stapler attached thereto. The closing lever was squeezed until it locked in place, followed by three strokes of the firing trigger to perform stapling and cutting with the knife. After the knife was returned to the original position in the fourth stroke, the lock of the stapler was released. The fire cutting properties were evaluated as “Good” when the stapling and cutting with the knife were performed without any trouble and the reinforcement was separated from the stapler without any trouble, and “Poor” when the stapling and cutting with the knife failed or the reinforcement was not separated from the stapler. The evaluation was not performed in Comparative Examples 1 and 2 because the reinforcements could not be mounted on the device.

(29) TABLE-US-00001 TABLE 1 Staple reinforcement for surgical stapler Adhesive layer Evaluation Viscosity* Amount Ease of Fabric (mPaS) Concen- of Thick- Adhesion passing Fire layer *in 2% tration solution Density ness strength Attach- through Shift cutting Material Material solution Form (%) (g) (g/cm.sup.3) (mm) (N/cm.sup.2) ability port resistance properties Example 1 PGA HPMC 5.1 Sponge 8 10 0.115 0.9 1.5 Good Good Fair Good Example 2 sheet 15 0.105 1.6 4.0 Good Good Good Good Example 3 20 0.092 2.4 5.8 Good Good Good Good Example 4 30 0.092 3.6 5.1 Good Good Good Good Example 5 40 0.088 4.9 8.3 Good Good Good Good Comparative Film 15 1.502 0.08 — Poor — — — Example 1 Example 6 PGA HPMC 37 Sponge 6 10 0.068 1.0 1.8 Good Good Fair Good Example 7 sheet 15 0.071 1.7 4.6 Good Good Good Good Example 8 20 0.063 2.5 5.3 Good Good Good Good Example 9 30 0.058 4.0 7.2 Good Good Good Good Example 10 40 0.062 4.9 9.7 Good Good Good Good Comparative Film 15 2.571 0.03 — Poor — — — Example 2 Example 11 PGA Pullulan 3.7 Sponge 10 20 0.136 2.4 8.6 Good Good Good Good Example 12 sheet 30 0.127 3.5 12.9 Good Good Good Good Example 13 40 0.123 5.1 10.6 Good Good Good Good Example 14 PGA Sodium 63 Sponge 10 20 0.073 2.2 3.8 Good Good Good Good Example 15 sheet alginate 30 0.064 3.9 4.8 Good Good Good Good Example 16 PGA Gelatin 2.0 Sponge 5 15 0.069 1.7 5.8 Good Good Good Good Example 17 sheet 20 0.072 2.1 5.8 Good Good Good Good Example 18 30 0.070 3.7 7.1 Good Good Good Good Example 19 40 0.070 4.3 6.3 Good Good Good Good

INDUSTRIAL APPLICABILITY

(30) The present invention can provide a staple reinforcement for a surgical stapler that can be used in surgical staplers of various sizes, is easily passed through ports, and is less likely to shift during operation of the surgical stapler.

REFERENCE SIGNS LIST

(31) 1 surgical stapler 2 conventional staple reinforcement for a surgical stapler 3 staple reinforcement for a surgical stapler of the present invention 31 fabric layer 32 sponge layer