WO2024129949A1

WO2024129949A1 - Luminal introducers and related methods

Info

Publication number: WO2024129949A1
Application number: PCT/US2023/083983
Authority: WO
Inventors: SR. James S. Franklin
Original assignee: Franklin Institute of Innovation, LLC
Priority date: 2022-12-14
Filing date: 2023-12-14
Publication date: 2024-06-20

Abstract

An introducer for facilitating insertion of an elongate surgical device, includes a sheath and an inflatable segment coupled thereto, where the sheath covers and forms a smooth contoured shape over a distal end of the elongate surgical device to facilitate insertion and advancement of the elongate surgical device into a patient.

Description

LUMINAL INTRODUCERS AND RELATED METHODS

Cross-Reference to Related Applications

[0001] This application claims priority' to U.S. Provisional Application No. 63/387,417, filed December 14, 2022, which is incorporated herein by reference.

Technical Field

[0002] The present disclosure relates generally to surgical instruments and methods, and more particularly to surgical introducers and related methods of using such introducers to introduce devices into a body cavity.

Background

[0003] Various types of surgical procedures may include introducing a surgical device into a body cavity or lumen. For example, a surgical stapler may be introduced into the bowel to join or attach tissue segments, e g., an anastomosis. A head assembly and a portion of a shaft of the stapler may be inserted into the bowel of the patient and advanced to a surgical site, while the handle remains outside of the patient to allow the clinician to control positioning and operation of the stapler. The head assembly generally may be relatively large in order to accommodate the various components for staple formation and for cutting the inner portions of the colon segments being joined. Further, the distal end face of the head assembly may be flat or relatively flat in order to cooperate with the mating portion of the anvil head, resulting in an abrupt edge along the outer circumference of the head assembly. Other surgical instruments may also include components that may be relatively large or include edges, comers, points, or transitions.

Various surfaces of a surgical instrument may contact internal tissue and surrounding anatomy as the surgical instrument is introduced and advanced into a body cavity.

[0004] Unfortunately, introduction of such conventional head assemblies of surgical staplers may result in anal sphincter injury and/or may damage the internal lining of the colon. Prior proposed efforts to provide atraumatic structures over such head assemblies to mitigate these risks may impede effective use of the stapler because the atraumatic structures cannot be easily or effectively moved away from the head assembly once the head assembly reaches the desired location of use within the patient.

[0005] Accordingly, there remains a need for improved introducers for surgical staplers and methods of using such introducers to introduce into patients and advance surgical instruments to a target site with ease, while reducing incidence of injury⁷ to the surrounding anatomy and complications for the patient. Brief Summary

[0006] Introducers for facilitating insertion of an elongate surgical device are provided.

[0007] In one aspect, the introducer includes a sheath extending between a proximal end and a distal end, where the sheath is configured to receive and cover a distal tip of the elongated surgical device. The introducer also includes an inflatable segment coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration, where the inflatable segment is configured to inflate about the distal tip of the elongated surgical device to facilitate insertion and advancement of the elongated surgical device. In some embodiments, the distal end of the sheath defines a distal opening. The distal opening may be configured to facilitate removal of the introducer from the elongate surgical device while the elongate surgical device is disposed within a body cavity of the patient. In some embodiments, a distal portion defining the distal end of the sheath has a narrower diameter than a proximal portion of the sheath. The distal portion may have a wall thickness greater than that of a proximal portion of the sheath. In some embodiments, the inflatable segment is coupled to the distal end of the sheath within an interior of the sheath. The inflatable segment may surround an internal lumen of the sheath, or may be defined with a wall of the sheath. In embodiments, the introducer also includes an inflation fluid container coupled to the inflatable segment by a supply tube. The inflation fluid container is configured to supply an inflation fluid to the inflatable segment, via the supply tube, to inflate the inflatable segment. In some embodiments, the inflation fluid container is a syringe. In some embodiments, the inflation fluid is sterile water or saline. In some embodiments, the introducer is also configured to remove the inflation fluid from the inflatable segment, via the supply tube, to deflate the inflatable segment. In embodiments, the sheath is formed of a material that is one or more of elastomeric, flexible, or stretchable. The material may comprise an elastomer, such as silicone or polyurethane.

[0008] In another aspect, an introducer for a colorectal stapler is provided, where the introducer includes a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover a distal tip of the colorectal surgical stapler, and an inflatable segment coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration. The inflatable segment may be configured to inflate about the distal tip of the colorectal surgical stapler to form a smooth contoured shape, which facilitates insertion and advancement of the distal tip of the colorectal surgical stapler into a patient. In some embodiments, the sheath is formed of a polymeric elastomer, such as silicone or polyurethane. [0009] In a further aspect, an assembly is provided, where the assembly includes a surgical instrument and an introducer. The surgical instrument may include a tubular shaft having a proximal end and a distal end, a handle extending from the proximal end of the tubular shaft, and a head assembly extending from the distal end of the tubular shaft. The introducer may be coupled to the head assembly of the surgical instrument, wherein the introducer is configured to facilitate insertion and advancement of the distal end of the surgical instrument into a patient. In some embodiments, the surgical instrument is a surgical stapler. In some embodiments, the introducer includes a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover at least the head assembly of the distal end of the surgical device, an inflatable portion coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration, and an inflation fluid container coupled to the inflatable portion by a supply tube. The inflatable portion may be configured to inflate about the distal end of the surgical instrument to form a smooth contoured shape.

[0010] In yet another aspect, a method of introducing a surgical instrument into a patient. The method includes covering at least a head assembly of the surgical instrument with an introducer, inserting the surgical instrument covered with the introducer into a body cavity of the patient, and advancing the surgical instrument covered with the introducer to a location in the body. In some embodiments, the method also includes inflating the inflatable segment before, during, or after advancing the surgical instrument. When the inflatable segment is inflated before advancement of the surgical instrument, the sheath may have a smooth contoured shape effective to facilitate insertion and advancement of the surgical instrument. In some embodiments, the method also includes the steps of deflating the inflatable segment after advancing the surgical instrument, and proximally withdrawing the sheath over the distal portion of the surgical stapler to expose the head assembly.

Brief Description of the drawings

[0011] The detailed description is set forth with reference to the accompanying drawings. The use of the same reference numerals may indicate similar or identical items. Various embodiments may utilize elements and/or components other than those illustrated in the drawings, and some elements and/or components may not be present in various embodiments. Elements and/or components are not necessarily draw n to scale.

[0012] FIG. 1 A is a perspective view of an introducer for a surgical instrument having a sheath and an inflatable segment, according to one or more embodiments of the present disclosure.

[0013] FIG. IB is a side view of the introducer of FIG. 1A. according to one or more embodiments of the present disclosure. [0014] FIG. 2 is a side view of a prior art surgical stapler, which may be used with the introducer of FIGS. 1 A-1B, according to one or more embodiments of the present disclosure. [0015] FIG. 3A-3B illustrates a sequence of attaching an introducer to a surgical instrument, according to one or more embodiments of the present disclosure.

[0016] FIGS. 4A-4C illustrates a method of inflating an introducer, according to one or more embodiments of the present disclosure.

[0017] FIGS. 5A-5D illustrates a method of deflating and removing an introducer from a distal portion of a surgical instrument, according to one or more embodiments of the present disclosure.

[0018] FIG. 6 illustrates an introducer with a retrieval strap to facilitate proximal displacement of the introducer from the distal portion of a surgical instrument, according to one or more embodiments of the present disclosure.

Detailed Description

[0019] Introducers have been developed for covering at least a distal portion of a surgical instrument, to protect internal tissue and anatomical features during insertion or advancement of the surgical instrument in a body cavity. In particular, the introducer is used to cover a distal portion of a conventional surgical stapler designed to be introduced into a body cavity and advanced to a predetermined site substantially atraumatically. For example, the stapler may be introduced through a patient’s anus to reach a desired region of the colon.

[0020] Such introducers advantageously may ease insertion and advancement of a distal portion of the surgical instrument, for example, a head assembly of a stapler to a desired location for performing a procedure, while reducing incidence of injury to the surrounding anatomy and corresponding complications for the patient. In particular, the introducers described herein may include a sheath and an inflatable segment that is configured to be positioned about a distal portion of the surgical instrument. The inflatable segment may be inflated prior to, during, or after introduction of the surgical instrument into the patient. While in the inflated configuration, the inflatable segment may cover a distal portion of the surgical instrument, for example, the head assembly, thereby inhibiting the distal portion from engaging the surrounding anatomy as the head assembly is advanced toward a desired location within a tissue segment.

[0021] After the surgical instrument reaches the desired location, the inflatable segment may be deflated, and the introducer may be proximally withdrawn from the distal portion of the surgical instrument. The instrument may subsequently be removed from the patient, for example, after a phase of a surgical procedure is completed, or after the surgical procedure is completed. [0022] FIGS. 1 A-1B depict an introducer 100 for use with a surgical instrument, such as the instrument 200 shown in FIG. 2, which is the distal end portion of a surgical stapler. The introducer 100 includes a sheath 102 extending between a proximal portion 104 and a distal portion 106. The proximal portion 104 includes a proximal end 108 defining a proximal opening 110 therein through which the surgical instrument 200 may be introduced into the sheath 102. The distal portion 106 may include a distal end 112 defining a distal opening 114. The distal opening 114 is configured to facilitate removal of the introducer 100 from the surgical instrument 200 so that the instrument 200 may be used for its intended purpose during a surgical procedure.

[0023] For example, the sheath 102 may be configured to receive and cover at least a distal end portion of the surgical instrument 200. For example, a head assembly 202 of the surgical instrument 200, disposed at the distal end 204 of a tubular shaft 206 of the instrument 100. may be inserted into the introducer 100 via the proximal opening 110 thereof. The distal end 204 of the instrument 100 may be passed through the sheath 102 until the head assembly 202 abuts the distal end 112 and is in contact with the distal opening 114 of the sheath 102. In some embodiments, the surgical instrument 200 is a surgical stapler, including a stapler configured to be introduced into/through channels of the anus, rectum, and/or colon.

[0024] The sheath may include, consist of, or consist essentially, of a stretchable material. That material may be a polymer, or copolymer, or polymeric blend. For instance, the material may include, consist of, or consist essentially of, an elastomer, such as a silicone or a polyurethane, e.g.. a biocompatible thermoplastic polyurethane, or TPU, as known in the art. [0025] In some embodiments, the distal portion 106 of the sheath 102 has a narrow er diameter than the proximal portion 104 of the sheath 102. In some embodiments, the distal portion 106 of the sheath 102 has a wider diameter than the proximal portion 104 of the sheath 102. In some embodiments, the distal portion 106 of the sheath 102 has a greater thickness than the proximal portion 104 of the sheath 102. In other embodiments, the distal portion 106 of the sheath 102 has a lesser thickness than the proximal portion 104 of the sheath 102.

[0026] In some embodiments, the introducer 100 includes an inflatable portion 116 coupled to the sheath 102, where the inflatable portion 116 is configured to move between a collapsed configuration and an inflated configuration. For example, the inflatable portion 1 16 of the sheath 102 may be configured to inflate about the distal tip 204 of the surgical instrument 200 to form a smooth contoured shape, w hich may facilitate insertion of the distal tip 204 of the instrument 200 into a patient. In some embodiments, the inflatable portion 116 is a balloon.

[0027] The inflatable portion 116 may be discrete or integrated with the sheath 102. In some embodiments, a portion of the sheath 102 may define the inflatable segment 110, for example, including the balloon. That is, the inflatable portion 116 may be defined within the sheath 102. In some embodiments, the sheath 102 may include a double-walled portion defining the inflatable portion 116 therein. In some embodiments, the inflatable portion 116 is coupled to an interior surface of the distal portion 106 of the sheath 102.

[0028] In some embodiments, the inflatable portion 116 may be filled with an inflation fluid before or after the introducer 100 has been stretched over the surgical instrument 200. The inflatable portion 116 may be attached to a supply tube 118 through which an inflation fluid is passed to inflate the inflatable portion 116. The inflation fluid may be water, a saline solution, air, or the like. In some embodiments, the supply tube 112 includes a port 120, as shown in FIG. 4 A, to which an inflation fluid container 122 may be coupled in order to supply the inflation fluid to the supply tube 118 and the inflatable portion 116. In some embodiments, the inflation fluid container 116 is a syringe.

[0029] The supply tube 118 may be fluidly connected to the inflatable portion 116 via a connector 124 disposed within the sheath 102, for example, as shown in FIGS. 4A-4C. The proximal end 108 of the sheath 102 may include an opening 126 configured to receive the supply line 118. The supply line 118 may then be provided to the connector 124 and the inflatable portion 116 of the sheath 102. When the supply line 118 is connected with the inflatable portion 116, the supply line 118 may be used to inflate the inflatable portion 116. [0030] Referring now to FIGS. 3A-3B, a sequence (300) of attaching the introducer 100 to the surgical instrument 200 is shown. Before the instrument 200 is introduced into the patient's body, the introducer 100 is pulled over the distal portion 204 of the instrument 200. More specifically, as shown in FIG. 3 A, the proximal opening 110 of the introducer 100 sheath 102 is aligned (302) with the head assembly 200 at the distal end 204 of the instrument 200 so that the introducer 100 may be secured to the instrument 200. Once the instrument 200 and the introducer 100 are aligned, the introducer 100 is advanced (304) in a proximal direction to cover the head assembly 202 of the instrument 200, as show n in FIG. 3B. The introducer 100, or at least a portion thereof, is secured to the instrument 200 by frictional engagement with the lateral surface of the distal portion 204 of the instrument 200. After the introducer 100 is secured about the instrument 200, the inflatable portion 116 of the introducer 100 may be inflated for use.

[0031] In some embodiments, as shown in FIGS. 4A-4C, the inflatable portion 116 is disposed within an interior wall 128 of the sheath 102, surrounding an internal lumen 130 thereof. The inflatable portion 116 may therefore expand at least partially into the internal lumen 130 of the sheath 102.

[0032] A method (400) of inflating the inflatable portion 116 of the introducer 100 is shown in greater detail in FIGS. 4A-4C. FIG. 4A depicts the introducer 100 in the non-inflated position prior to use (402). At this point, the fluid supply container 122 is attached to the fluid supply line 118 via the port 120. When the inflatable portion 116 is in the non-inflated state, the internal wall 128 does not protrude into the internal lumen 130 of the sheath 102. As the fluid supply container 122 is used to transfer fluid (404), via the supply line 118, to the inflatable portion 116, the inflatable portion begins to expand. For example, the inflatable portion 116 may expand such that the internal wall 128 may begin to protrude into the internal lumen 130 of the sheath 130 at least at the distal end 112 of the sheath 102. Inflation of the inflatable portion 116 may also cause the overall profile of the introducer 100 to expand. In such embodiments, the distal portion 106 of the introducer 100 may have a larger diameter than the proximal portion 104 of the introducer 100 when the inflatable portion 116 is partially or fully inflated. Once the inflatable portion 116 is fully inflated (406). as shown in FIG. 4C, the introducer 100 and the surgical instrument may be inserted into a body cavity of the patient.

[0033] After the surgical instrument 200, with the introducer 100, is properly placed for use within the patient, the inflatable segment 116 may be deflated to facilitate removal of the introducer 100 from the surgical instrument 200. For example, the inflatable portion 116 may be deflated, and the introducer 100 may be retracted circumferentially off of the distal end 204 of the surgical instrument 200, which may be effective to allow the surgical instrument 200 to be used as intended w ithin the patient without interference from the introducer 100. In some embodiments w here the surgical instrument 200 is a stapler, for example, proximal retraction of the introducer 100 may enable use of the stapler to safely and effectively complete a surgical procedure such as an anastomosis following a bowel resection.

[0034] An exemplary method (500) of deflating and removing the introducer 100 is shown in FIGS. 5A-5D. Insertion of the surgical instrument 200 is accomplished with the introducer in the fully inflated state (502), as shown in FIG. 5A. Following insertion, the inflatable portion 116 may be partially or fully deflated (504) by withdrawing the inflation fluid from the inflatable portion. For example, the inflation fluid may be removed from the inflatable portion 116 via the supply tube 118. In some embodiments where the fluid supply container 122 is a syringe, for example, the syringe may draw fluid back in from the inflatable portion 116 through the supply line. Deflation of the inflatable portion 116 may reduce the profile of at least the distal portion 106 of the introducer 100 sheath 102. The extent to which the internal wall 128 protrudes into the internal lumen 130 defined by the sheath 102 may also be reduced, thereby enabling movement of the sheath 102 with respect to the distal end 204 and head assembly 202 of the surgical instrument 200.

[0035] After the inflatable portion 116 is deflated to the degree necessary to facilitate removal of the sheath 102 from the surgical instrument 200, the sheath 102 may be retracted (506) in a proximal direction to expose the head assembly 202 of the instrument 200, as shown in FIG. 5C.

[0036] In some embodiments, as shown in FIG. 6, the introducer 100 may include one or more tethers 132 (e.g., retrieval straps) attached to the proximal end 108 of the sheath 102 and extending out of the patient to enable a surgeon to grasp the one or more tethers and pull the introducer in a proximal direction to facilitate removal of the introducer from at least the distal end face of the head assembly of the instrument 200, as shown in FIG. 5C. In some embodiments, the supply line may be used to facilitate removal of the introducer from at least the distal end of the head assembly of the instrument, either alone or in conjunction with the one or more retrieval straps 132.

[0037] As shown in FIG. 5D, the introducer 100 may be fully removed (508) from the distal end 204 of the surgical instrument 200 to prepare the instrument 200 for use. In some embodiments, the sheath 102 is only partially removed from the instrument 200, and remains disposed around the proximal base 208 and/or handle 210 of the instrument 200 until the procedure is complete. The entire instrument 200 and the attached but separated or withdrawn introducer 100 may then be removed. For example, the stapler may be retracted with the introducer remaining attached to the stapler, or otherwise be withdrawn together with the introducer. In other embodiments, the introducer 100 may be fully removed from the surgical instrument 200 prior to proceeding with the surgical procedure.

[0038] Some embodiments of the present disclosure can be described in view of one or more of the following:

EMBODIMENTS

[0039] Embodiment 1. An introducer for an elongated surgical device, the introducer comprising a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover a distal tip of the elongated surgical device, and an inflatable segment coupled to the sheath and configured to move betw een a collapsed configuration and an inflated configuration, wherein the inflatable segment is configured to inflate about the distal tip of the elongated surgical device to facilitate insertion and advancement of the elongated surgical device.

[0040] Embodiment 2. The introducer of Embodiment 1, wherein the distal end of the sheath defines a distal opening.

[0041] Embodiment 3. The introducer of Embodiment 2, wherein the distal opening is configured to facilitate removal of the introducer from the elongate surgical device while the elongate surgical device is disposed within a body cavity of a patient. [0042] Embodiment 4. The introducer of any one of Embodiments 1 to 3, wherein a distal portion defining the distal end of the sheath has a narrower diameter than a proximal portion of the sheath.

[0043] Embodiment 5. The introducer of any one of Embodiments 1 to 3, wherein the distal portion has a wall thickness greater than that of a proximal portion of the sheath.

[0044] Embodiment 6. The introducer of any one of Embodiments 1 to 5, wherein the inflatable segment is coupled to the distal end of the sheath within an interior of the sheath. [0045] Embodiment 7. The introducer of any one of Embodiments 1 to 6, wherein the inflatable segment surrounds an internal lumen of the sheath.

[0046] Embodiment 8. The introducer of any one of Embodiments 1 to 7, wherein the inflatable segment is defined within a wall of the sheath.

[0047] Embodiment 9. The introducer of any one of Embodiments 1 to 8, further comprising an inflation fluid container coupled to the inflatable segment by a supply tube.

[0048] Embodiment 10. The introducer of Embodiment 9, wherein the inflation fluid container is configured to supply an inflation fluid to the inflatable segment, via the supply tube, to inflate the inflatable segment.

[0049] Embodiment 11. The introducer of Embodiment 10, wherein the inflation fluid container comprises a syringe.

[0050] Embodiment 12. The introducer of Embodiment 10 or 11, wherein the inflation fluid is sterile water or saline.

[0051] Embodiment 13. The introducer of any one of Embodiments 10 to 12. wherein the introducer is also configured to remove the inflation fluid from the inflatable segment, via the supply tube, to deflate the inflatable segment.

[0052] Embodiment 14. The introducer of any one of Embodiments 1 to 13, wherein the sheath comprises a polymeric material, such as an elastomeric material.

[0053] Embodiment 15. The introducer of Embodiment 14, wherein the elastomeric material comprises silicone, polyurethane (e.g., a TPU), or a combination thereof.

[0054] Embodiment 16. An introducer for a colorectal surgical stapler, the introducer comprising a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover a distal tip of the colorectal surgical stapler, and an inflatable segment coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration, wherein the inflatable segment is configured to inflate about the distal tip of the colorectal surgical stapler to form a smooth contoured shape, which facilitates insertion and advancement of the distal tip of the colorectal surgical stapler into a patient. [0055] Embodiment 17. The introducer of Embodiment 16, wherein the sheath comprises an elastomer, such as silicone, polyurethane (e.g., a TPU) or a combination thereof.

[0056] Embodiment 18. An assembly comprising (i) a surgical instrument comprising a tubular shaft having a proximal end and a distal end, a handle extending from the proximal end of the tubular shaft, and a head assembly extending from the distal end of the tubular shaft, and (ii) an introducer coupled to the head assembly of the surgical instrument, wherein the introducer is configured to facilitate insertion and advancement of the distal end of the surgical instrument into a patient.

[0057] Embodiment 19. The assembly of Embodiment 18, wherein the surgical instrument is a surgical stapler.

[0058] Embodiment 20. The assembly of Embodiment 18 or 19, wherein the introducer comprises a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover at least the head assembly of the distal end of the surgical device, an inflatable portion coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration, and an inflation fluid container coupled to the inflatable portion by a supply tube.

[0059] Embodiment 21. The assembly of Embodiment 20, wherein the inflatable portion is configured to inflate about the distal end of the surgical instrument to form a smooth contoured shape.

[0060] Embodiment 22. A method of introducing a surgical instrument into a patient, the method comprising covering at least a head assembly of the surgical instrument with the introducer of any one of Embodiments 1 to 15, inserting the surgical instrument covered with the introducer into a body cavity' of the patient, and advancing the surgical instrument covered with the introducer to a location in the body.

[0061] Embodiment 23. The method of Embodiment 22, further comprising inflating the inflatable segment before, during, or after advancing the surgical instrument.

[0062] Embodiment 24. The method of Embodiment 23, wherein the inflatable segment is inflated before advancement of the surgical instrument such that the sheath has a smooth contoured shape effective to facilitate insertion and advancement of the surgical instrument. [0063] Embodiment 25. The method of any one of Embodiments 22 to 24, further comprising deflating the inflatable segment after advancing the surgical instrument, and proximally withdraw ing the sheath over the distal portion of the surgical stapler to expose the head assembly.

[0064] While the disclosure has been described with reference to a number of exemplary embodiments, it would be understood by those skilled in the art that the disclosure is not limited to such embodiments. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutes, or equivalent arrangements not described herein, but which are commensurate with the spirt and scope of the disclosure. Modifications and variations of the devices, systems, assemblies, kits and methods described herein will be obvious to those skilled in the art from the foregoing detailed description. Such modifications and variations are intended to come within the scope of the appended claims.

Claims

CLAIMS That which is claimed is:

1. An introducer for an elongated surgical device, the introducer comprising: a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover a distal tip of the elongated surgical device; and an inflatable segment coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration, wherein the inflatable segment is configured to inflate about the distal tip of the elongated surgical device to facilitate insertion and advancement of the elongated surgical device.

2. The introducer of claim 1, wherein the distal end of the sheath defines a distal opening.

3. The introducer of claim 2, wherein the distal opening is configured to facilitate removal of the introducer from the elongate surgical device while the elongate surgical device is disposed within a body cavity⁷ of a patient.

4. The introducer of claim 1, wherein a distal portion defining the distal end of the sheath has a narrower diameter than a proximal portion of the sheath.

5. The introducer of claim 1, wherein the distal portion has a wall thickness greater than that of a proximal portion of the sheath.

6. The introducer of claim 1, wherein the inflatable segment is coupled to the distal end of the sheath within an interior of the sheath.

7. The introducer of claim 1, wherein the inflatable segment surrounds an internal lumen of the sheath.

8. The introducer of claim 1, wherein the inflatable segment is defined within a wall of the sheath.

9. The introducer of claim 1, further comprising an inflation fluid container coupled to the inflatable segment by a supply tube. The introducer of claim 9, wherein the inflation fluid container is configured to supply an inflation fluid to the inflatable segment, via the supply tube, to inflate the inflatable segment. The introducer of claim 10, wherein the inflation fluid container is a syringe. The introducer of claim 10, wherein the inflation fluid is sterile water or saline. The introducer of claim 10, wherein the introducer is also configured to remove the inflation fluid from the inflatable segment, via the supply tube, to deflate the inflatable segment. The introducer of claim 1, wherein the sheath comprises an elastomeric material. The introducer of claim 14, wherein the elastomeric material comprises a silicone, a polyurethane, or a combination thereof. An introducer for a colorectal surgical stapler, the introducer comprising: a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover a distal end portion of the colorectal surgical stapler; and an inflatable segment coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration, wherein the inflatable segment is configured to inflate about the distal tip of the colorectal surgical stapler to form a smooth contoured shape, which facilitates insertion and advancement of the distal end portion of the colorectal surgical stapler into a patient. The introducer of claim 16, further comprising at least one tether having a first end end connected to the sheath and an opposing second end extending toward a handle of the colorectal surgical stapler, wherein the at least one tether is configured to be pulled to displace the sheath in a proximal direction to uncover the distal end portion of the colorectal surgical stapler after the distal end portion of the colorectal surgical stapler has been advanced into the patient. An assembly comprising: a surgical instrument comprising a tubular shaft having a proximal end and a distal end, a handle extending from the proximal end of the tubular shaft, and a head assembly extending from the distal end of the tubular shaft; and an introducer coupled to the head assembly of the surgical instrument, wherein the introducer is configured to facilitate insertion and advancement of the distal end of the surgical instrument into a patient. The assembly of claim 18, wherein the surgical instrument is a surgical stapler. The assembly of claim 18 or 19, wherein the introducer comprises: a sheath extending between a proximal end and a distal end, the sheath being configured to receive and cover at least the head assembly of the distal end of the surgical device; an inflatable portion coupled to the sheath and configured to move between a collapsed configuration and an inflated configuration; and an inflation fluid container coupled to the inflatable portion by a supply tube. The assembly of claim 20, wherein the inflatable portion is configured to inflate about the distal end of the surgical instrument to form a smooth contoured shape. A method of introducing a surgical instrument into a patient, the method comprising: covering at least a head assembly of the surgical instrument with the introducer of any one of claims 1 to 17; inserting the surgical instrument covered with the introducer into a body cavity of the patient; and advancing the surgical instrument covered with the introducer to a location in the body. The method of claim 22, further comprising inflating the inflatable segment before inserting or before advancing the surgical instrument. The method of claim 23, wherein the inflated inflatable segment has a smooth contoured shape effective to facilitate atraumatic insertion and advancement of the surgical instrument. The method of any of claims 22 to 24, further comprising: deflating the inflatable segment after advancing the surgical instrument; and proximally withdrawing the sheath over the distal portion of the surgical stapler to expose the head assembly.