WO2015157621A1

WO2015157621A1 - Robotic retractor with soft fiber-reinforced actuator

Info

Publication number: WO2015157621A1
Application number: PCT/US2015/025280
Authority: WO
Inventors: Andrew Harris; Panagiotis POLYGERINOS; Arthur MOSER; Conor Walsh
Original assignee: President And Fellows Of Harvard College
Priority date: 2014-04-10
Filing date: 2015-04-10
Publication date: 2015-10-15

Abstract

Bodily tissue (e.g., a colon) is retracted using a robotic retractor comprising an elongated handle and a fiber-reinforced soft actuator mounted at an end of the elongated handle. The handle is used to insert the soft actuator inside a body of an organism; and the soft actuator is positioned alongside tissue to be retracted inside the body. Fluid is pumped into the soft actuator, bending the soft actuator around the tissue to grasp the tissue; and the grasped tissue is displaced with the soft actuator.

Description

ROBOTIC RETRACTOR WITH SOFT FIBER-REINFORCED ACTUATOR

BACKGROUND

Using laparoscopic instruments, surgeons can perform complex abdominal surgeries all through small incisions usually less than 1.5 cm long. The abdomen is inflated with CO₂ gas to create a field of vision and working space and a laparoscope (camera) is used to view the interior organs. Minimally invasive surgeries (MIS) have many advantages to open surgeries, including reduced pain and recovery times.

However, significant time is spent adjusting the organs within the field of view so that the surgeon has clear access to the organs s/he is operating on. The colon is one such organ that often requires a significant amount of time and effort to adjust and keep out of the surgeon's way, especially in overweight patients, this process frequently can take up to 45 minutes in a pancreatic cancer case

(pancreaticoduodenectomy or Whipple procedure) and the current solution involves tilting the patient at a slightly upright angle that allows gravity to assist in retracting the colon. Further, surgeons often use ad hoc tools, such as gauze, to prop up the colon on a "pedestal". This practice introduces a misuse of current tools, while not fully creating a clear view behind the colon. The colon may then fall off this pedestal, causing the surgeon to perform the retraction process again before continuing the surgery.

Since their introduction in 1910, laparoscopic surgeries have offered doctors a minimally invasive way to perform operations that result in reduced pain, shorter hospital stays, and improved postoperative recovery for patients. Although

minimally invasive surgeries have been developed to improve or replace open surgeries on many organs, laparoscopy is primarily used as a diagnostic and staging tool in several procedures, such as pancreatic cancer removal. One reason for the lag in development of the laparoscopic procedures, which lasts several hours, is that retracting tissues in order to access organs such as the pancreas is difficult and time consuming with current tools. For example, in the pancreatic cancer removal procedure, after the abdomen is insufflated, the colon must be mobilized— that is, connective tissue from the colon must be removed so that the organ can be manipulated. There is a market opportunity for soft MIS laparoscopic organ retraction tools that can improve surgery times and reduce complications due to trauma caused from conventional rigid retraction devices.

Retractors are used by surgeons and surgical assistants to gain better view and access to tissues by adjusting the position of organs in front of those tissues. There are three main types of retraction devices used during laparoscopic surgeries: (1) expandable membranes, (2) multi-jointed rods, and (3) inflatable retractors.

1) Expandable Membranes:

Many laparoscopic retractors employ membranes to adjust the position of tissues. These devices have the following four main functional components: (a) a cannula that is used for insertion, (b) "arms" inside the cannula that expand to form the scaffolding for the membrane, (c) the membrane which provides an atraumatic surface for manipulating tissue, and (d) a mechanism for releasing the device's "arms" and expanding the membrane. In one such example (described in US

5,178,133), three "arms" are first closed and covered in a latex sheath with tubes that fit around the "arms." The cannula is inserted through a trocar and the distal end is placed near the organ to be retracted. Once the tissue has been located, the "arms" are opened using a scissor-like motion such that the sheath forms a planar surface that is used to move tissue. This type of retractor is generally used for active retraction, so a surgeon or surgical assistant must hold and manipulate the cannula during use. Additionally, because the retractor requires active manipulation, it occupies one trocar port during use.

2) Multi-Jointed Rods:

A second type of retraction device uses a multi-jointed rod that can change shape intracorporeally to create a surface on which to rest tissue. This type of retractor, described in US 6,248,062 Bl, is generally used for long-term retraction of large organs. The leading product in this category of retractor is the ENDOFLEX retractor, developed by Professor McMahon and Peter Moran at Surgical

Innovations in 1992.This type of retractor consists of a series of links that are actuated by an internal cable. The device is inserted into the body in a straight configuration. Once inside the body, the surgeon rotates an actuating mechanism at the proximal end that pulls the cable and causes the shaft to change shape. The links change position to form a closed geometric shape at the distal end of the shaft (see FIG. 5). Because this device is used for long-term organ retraction during surgery, it proximal end of the device is anchored to the patient's bed. The shaft of the retractor occupies one trocar port throughout the surgery.

3) Inflatable Retractors:

A third method for tissue retraction is through inflation. Inflatable retraction devices take one of two forms: (a) those which remain attached to the inflation source throughout the duration of the surgery and (b) those that are inserted with an infusion source that is removed once the retractor has been inflated. An example of the first type (described in US 5,439,476) is in the form of a rigid rod with a balloon affixed to the distal tip. This balloon is fabricated with a stiff plastic, such that it inflates in only one direction. The outer surface is smooth and can be covered in a soft nylon mesh so as to ensure that the device is able to retract tissue atraumatically. For this device, the balloon covers several perforations at the distal tip of the rod for inflation and is not designed to facilitate its removal.

An example of the second type includes an inflatable balloon and a detachable manipulator that is used for inflation. The balloon is rolled to fit through a trocar port and is then inflated intracorporeally using the manipulator. As the balloon inflates, it elevates and tilts the desired organs so as to displace them during surgery. When the balloon is maximally inflated, the inflation manipulator can be removed. Additionally, although the device is not deployable, it does have separate inflation and inflator elements. The ability to separate these two elements may provide insight into how to inflate a deployable device intracorporeally. SUMMARY

A robotic retractor device with a fiber-reinforced actuator and methods for using it {e.g., in surgery) are described herein, where various embodiments of the apparatus and methods may include some or all of the elements, features and steps described below. In various embodiments, a robotic retractor includes an elongated handle; a fiber-reinforced soft actuator mounted at an end of the elongated handle; and a pump coupled in fluid communication with the inflatable chamber and configured to pump fluid into the inflatable chamber. The soft actuator comprises an elongated elastomeric body that defines an inflatable chamber; a fiber reinforcement wrapped around the elongated elastomeric body; and a strain-limiting layer extending along one side of the soft actuator, wherein the strain-limiting layer is configured to cause the soft actuator to bend toward the side of the strain-limiting layer.

The robotic retractor can further include a biocompatible sheath covering the elongated elastomeric body and the fiber reinforcement. In additional embodiments, the soft actuator and the handle can have dimensions of 15 mm or less orthogonal to the elongated axis; and the handle can be 5-50 cm long or within the expected range for laparoscopic minimally invasive instruments.

In additional embodiments, the soft actuator has a hemi-circle-shaped cross- section with a straight side and a convex side, wherein the strain-limiting layer is positioned along the straight side. The soft actuator can also includes a latch at an end of the soft actuator opposite from where the soft actuator is mounted to the handle.

The robotic retractor can also include a suction device coupled with an end of the soft actuator and detachably coupled with the handle and configured to generate a suction by which the soft actuator can be adhered to a surface when the suction device is detached from the handle. In additional embodiments, the robotic retractor can include at least one magnet at an end of the soft actuator by which the soft actuator can be adhered to a surface.

A method for retracting bodily tissue uses a robotic retractor comprising an elongated handle and a fiber-reinforced soft actuator mounted at an end of the elongated handle. The method includes using the handle to insert the soft actuator inside a body of an organism {e.g., a human); positioning the soft actuator alongside tissue {e.g., a colon) to be retracted inside the body; pumping fluid into the soft actuator, bending the soft actuator around the tissue to grasp the tissue; and retracting the grasped tissue with the soft actuator to displace the grasped tissue. In various embodiments, the grasped tissue is displaced toward an inner wall of human skin. In additional embodiments, the tissue is displaced during a surgical operation.

Additionally, the soft actuator can be inserted into the body through a trocar port. Further, the soft actuator further can include a strain-limiting layer along a side along which the soft actuator bends.

The apparatus described herein can provide long-term retraction of tissues or organs during minimally invasive surgery (MIS) using soft robotics technology. In particular, soft elastomeric fiber-reinforced actuators can be utilized that use air pressure to deform (curl), providing a number of advantages over traditional mechanical retractors. Most notably, soft actuators do not require motors and can more easily be made soft so as to comply with tissue/organs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a soft retractor 12 with a magnified cut-away view of the soft actuator 16.

FIG. 2 shows a soft fiber-reinforced bending actuator 16 in an unpressurized state with a magnified cut-away view of the fiber reinforcements 28.

FIG. 3 shows the soft fiber-reinforced bending actuator 16 of FIG. 2 in a pressurized state.

FIG. 4 is a partially sectioned illustration of an embodiment of a soft fiber- reinforced actuator 16

FIG. 5 is a schematic illustration of stages of the soft fiber-reinforced actuator fabrication process.

FIG. 6 shows an embodiment of a soft retractor 12 with a suction device 50 that attaches to an inner abdomen wall in the body interior 36 to free the trocar port 28.

FIG. 7 shows an embodiment of a soft retractor 12 with suction devices 50 to attach to the inner abdomen wall at both ends of the soft actuator 16, thereby freeing the trocar port 28. FIG. 8 shows an embodiment of a soft retractor 12 with a soft actuator 16 that has pre-programmed bending motions at various locations along its length to hold the retracted organ 40against the abdomen well.

FIG. 9 shows an embodiment of the soft retractor 12 inserted through a trocar port 38 through the skin 34 into the interior 36 a human body.

FIG. 10 shows the soft retractor 12 of FIG. 9 with the soft actuator 16 inflated to conform around the colon 40.

FIG. 11 shows the soft retractor 12 of FIGS. 9 and 10 retracting the colon 40.

FIG. 12 shows a simulation of colon retraction conducted in-vitro.

In the accompanying drawings, like reference characters refer to the same or similar parts throughout the different views; and apostrophes are used to

differentiate multiple instances of the same or similar items sharing the same reference numeral. The drawings are not necessarily to scale; instead, emphasis is placed upon illustrating particular principles in the exemplifications discussed below.

DETAILED DESCRIPTION

The foregoing and other features and advantages of various aspects of the invention(s) will be apparent from the following, more -particular description of various concepts and specific embodiments within the broader bounds of the invention(s). Various aspects of the subject matter introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the subject matter is not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

Unless otherwise herein defined, used or characterized, terms that are used herein (including technical and scientific terms) are to be interpreted as having a meaning that is consistent with their accepted meaning in the context of the relevant art and are not to be interpreted in an idealized or overly formal sense unless expressly so defined herein. For example, if a particular composition is referenced, the composition may be substantially (though not perfectly) pure, as practical and imperfect realities may apply; e.g., the potential presence of at least trace impurities {e.g., at less than 1 or 2%) can be understood as being within the scope of the description; likewise, if a particular shape is referenced, the shape is intended to include imperfect variations from ideal shapes, e.g., due to manufacturing

tolerances. Percentages or concentrations expressed herein can represent either by weight or by volume. Processes, procedures and phenomena described below can occur at ambient pressure {e.g., about 50-120 kPa— for example, about 90-110 kPa) and temperature {e.g., -20 to 50°C— for example, about 10-35°C) unless otherwise specified.

Although the terms, first, second, third, etc., may be used herein to describe various elements, these elements are not to be limited by these terms. These terms are simply used to distinguish one element from another. Thus, a first element, discussed below, could be termed a second element without departing from the teachings of the exemplary embodiments.

Spatially relative terms, such as "above," "below," "left," "right," "in front," "behind," and the like, may be used herein for ease of description to describe the relationship of one element to another element, as illustrated in the figures. It will be understood that the spatially relative terms, as well as the illustrated configurations, are intended to encompass different orientations of the apparatus in use or operation in addition to the orientations described herein and depicted in the figures. For example, if the apparatus in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term, "above," may encompass both an orientation of above and below. The apparatus may be otherwise oriented {e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Further still, in this disclosure, when an element is referred to as being "on," "connected to," "coupled to," "in contact with," etc., another element, it may be directly on, connected to, coupled to, or in contact with the other element or intervening elements may be present unless otherwise specified.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of exemplary embodiments. As used herein, singular forms, such as "a" and "an," are intended to include the plural forms as well, unless the context indicates otherwise. Additionally, the terms, "includes," "including," "comprises" and "comprising," specify the presence of the stated elements or steps but do not preclude the presence or addition of one or more other elements or steps.

Additionally, the various components identified herein can be provided in an assembled and finished form; or some or all of the components can be packaged together and marketed as a kit with instructions {e.g., in written, video or audio form) for assembly and/ or modification by a customer to produce a finished product.

Soft robotic actuators, such as the soft retractor 12 discussed below, can use air pressure (or other fluids) to deform elastomer joints, providing a number of advantages over traditional mechanical actuators. For example, soft robotic actuators do not require motors and can more easily be made soft so as to comply with tissue.

An embodiment of the soft retractor 12 can be seen in FIG. 1 connected to a laparoscopic handle 14 for ease of positioning and retraction. The elongated handle 14 can be, e.g., 10-50 cm long. The soft retractor 12 comprises a fiber-reinforced actuator 16 that, when deflated, fits through a 15 mm trocar port 38, and a locking mechanism (latch) 18 that secures the actuator 16 in place when the tissue/ organ is retracted. Pressurization of the actuator 16 and hence bending can be achieved through a proximal handle 14 that incorporates a pump 20 configured for manual pumping action {e.g., incorporating a medical grade syringe or a reciprocating manual pump) or, alternatively, an active pumping mechanism 20 {e.g., connecting the handle 14 to an external pressure source or having an automated on-board pump), as shown in FIG. 1. Also, the locking mechanism 18 can be in the form of one or more magnets that automatically lock the actuator 16 in place when pressurized.

The soft actuator 16 can be seamlessly integrated with existing laparoscopic tools and handles 14 {e.g., swapping it in place of an existing rigid retractor).

Furthermore, the soft actuator 16 can be programmed to achieve the desired bending radius, while its size (width and length) can be tuned during fabrication to retract organs with variable weight and size. An advantageous feature of the technology is the ability to stably position the retractor 12 at the desired location and subsequently retract a tissue or organ without having to create contact or pinch using rigid tools that can potential cause raptures and bleeding of organs or other tissue. This reduced risk of injury is achieved through partial pressurization of the actuator 16 during positioning, thereby changing the stiffness of the actuator 16 and enabling the actuator 16 to be safely pushed through tissue. Another advantage of this design is the ability to pressurize the actuator 16 in a confined space, such as in the abdomen, and achieve full actuator bending without causing any internal organ damage thanks to the inherent compliance and flexibility of the actuator 16, thereby ensuring that the retractor 12 can create a secure and soft loop around the organ even when there is no room for the laparoscopic tool to reach.

In particular embodiments, the soft actuator 16 can be activated by

pressurized air. The reinforced actuator 16 can be made from an elastomeric polymer {e.g., a hyper-elastic silicone); and it defines an inflatable chamber 22 and includes a flexible strain-limiting layer 30 (including, e.g., inextensible fibers or fabric) adhered to a side of the reinforced actuator 16. The actuator 16 also includes a wrapping of a strain-limiting fiber reinforcement 28 (formed, e.g., of a para-aramid fiber, such as KEVLAR fiber from DuPont) to restrict expansion of the chamber 22 in certain directions {e.g., radially) and is covered with a flexible outer protection layer (sheath) 26 (formed of a biocompatible composition, such as silicone). A cross- sectional model of a basic soft bending fiber-reinforced actuator 16 can be seen in FIG. 2, exhibiting the inner chamber 22, the structural elastomer, the strain-limiting fiber wrapping 28, the strain-limiting layer 30, and the protective outer layer 26. The fiber reinforcements 28 and stain-limiting layer 30 are also shown separately above and below the composite structure. FIGS. 3 and 4, respectively, show a fiber- reinforced soft actuator 16 in unpressurized and pressurized states. Additional discussion of suitable structures for the soft actuator 16 can be found in

PCT/US14/62844 (Harvard / Kevin Galloway, et a/.).

The soft fiber-reinforced bending actuator 16 can be fabricated using a multi- step molding process and can comprise the following four parts: (i) a hemi-circle elastomeric polymer (including caps at the distal and proximal ends), (ii) circumferential fiber windings 28 that run along the length of the actuator 16, (iii) an inextensible base layer 30, and (iv) a soft coating material (sheath) 26 that

encapsulates the entire system. The circumferential reinforcement provided by the fibers 28, limits radial expansion and promotes linear extension, while the strain- limiting layer 30 at the base restricts linear extension on one face of the actuator 16. Therefore, as the actuator 16 is pressurized, part of it expands while the strain- limited portion restrains any linear expansion along one surface, producing a bending motion.

To offer complete control over every aspect of the assembled actuator 16 including geometry, material properties, and the pattern of fiber reinforcements 28, a multi-step molding approach was used. First, an inner rubber layer is molded to form the body of the actuator 16. The molds 42 for the actuator 16 were 3D printed with an Objet Connex 500 printer. The inner rubber layer (formed of ELASTOSIL M4601 A/B from Wacker Chemie AG, Germany) was formed around a half round steel rod 46 that was used to define the interior, hollow portion of the actuator 16, as shown in illustration (a) of FIG. 5. The molded rubber was then allowed to set for 24 hours. Woven fiberglass (S2-6522 from USComposites of Florida, USA) was glued to the flat face of the inner rubber layer to serve as a strain-limiting layer 30 that restricts linear expansion on that side of the actuator 16 while allowing for expansion on an opposite side of the actuator 16 (to enable bending) and that can provide for pre-programmed actuation motion, as shown in illustration (b) of FIG. 5.

After molding the inner rubber layer, fiber reinforcements 28 to prevent radial expansion were added to the surface, as shown in illustration (c) of FIG. 5.

Specifically, a single KEVLAR fiber of 0.38 mm diameter was wound in a double helix pattern around the length of the actuator body 24. Raised features in the mold 42 were transferred to the actuator surface to define the fiber path for consistency of fiber placement.

The fiber reinforcements 28 were further secured (and prevented from moving upon inflation of the actuator 16 by placing the entire assembly into another mold 42 to encapsulate the actuator body 24 in a 1.0-mm-thick silicone layer 26 (formed, e.g., of ECOFLEX 0030 or DRAGON SKIN 20 silicone from Smooth-on Inc., of Pennsylvania, USA), as shown in illustration (d) of FIG. 5. The actuator body 24 was then removed from the mold 42 and the half round steel rod 46. The first open end was capped by placing it into a small cup of uncured silicone. Once this end cured, a vented screw 32 (shown in FIG. 3 and 4) was fed through the 15 mm thick silicone cap to form the mechanical connection for the pneumatic tubes coupled with the pump for supplying and removing actuating fluid to and fro the chamber 22 of the soft actuator 16. The other open end was capped in a similar manner.

The actuator design can be tuned by varying a number of geometrical parameters including the wall thickness of the actuator 16, the length of the actuator 16, the diameter of the hemi-circle sectional shape, as well as the fiber winding pitch and orientation (see FIGS. 2 and 3). Changing any of these parameters will result in different performance. Furthermore, the shape of the cross section can also significantly affect the response of the system as the magnitude of the area

determines the force generated by the pressure acting on it and it will also influence the stress distribution in the elastic material as it resists expansion.

In an additional embodiment, as shown in FIG. 6, the retractor 12 can incorporate a suction cup device or an array of suction cups 50 (such as an

OCTOPUS3 tissue stabilizer from Medtronic pic, which is designed for open surgery and is mountable on the surgical table) or magnets to attach to the inner abdomen wall and free the trocar port 38. The fiber-reinforced actuator 16 is programmed to hold the weight of the organ without requiring a locking mechanism. At left, the retractor 12 enters the body through a trocar port 38. As shown in the middle frame, a suction device 50 attaches from the body interior 36 to the interior side of abdominal skin 34, where the actuator 16 engages to form a hook. At right, the colon 40 is placed in the hook created by the fiber-reinforced actuator 16.

In another exemplification, shown in FIG. 7, the retractor 12 can incorporate a suction cup device or an array of suction cups 50 or magnets to attach to the inner abdomen wall from both ends of the soft actuator 16 and free the trocar port 38. At left, the retractor 12 again enters the body through a trocar port 38. In the middle frame, a suction device 50 attaches to the interior side of abdominal skin 34 to form a surgical band with two fixture points that holds up the colon 40. The fixture point proximal to the handle 14 incorporates a one way valve that, upon detachment from the handle 14, enables the actuator 16 to preserve its pressure and shape. A side view of the colon 40 contained in the band is shown at right.

In yet another exemplification, shown in FIG. 8, the retractor 12 can incorporate preprogrammed bending motions (flexible joints) at various locations along its length to hold a retracted organ against the abdomen wall. At left, the soft actuator 16 enters the body through a trocar port 38. At center, the surgeon moves a second section of the actuator 16 into place with the aid of an end effector 52; then fluid pressurization changes the stiffness of the soft actuator section enabling the actuator 16 to retract and hold the organ in the desired position. The surgeon then moves a first section of the actuator 16 into place with the aid of the end effector 52; then the same pressurization process starts again. By jamming in multiple sections, the retractor 12 may not obscure as much of the working area as a traditional retractor because the retractor 12 of this embodiment need not be completely straight when it is fully jammed and can conform to the shape of the tissue.

Exemplar ^r Application: Pancreatic Cancer Surgery:

Pancreatic cancer is both difficult to discover and to treat; for over 80% of patients, by the time of discovery, the tumor has already spread so extensively that it cannot be completely removed. The cancer has a very low survival rate and 95% of the people diagnosed do not survive beyond five years.

During pancreatic cancer surgery, the head of the pancreas, the gallbladder, part of the small intestine, the pylorus, and the lymph nodes near the area of surgery are removed. The area is then reconstructed so that the pancreatic digestive enzymes, bile, and stomach contents will flow to the small intestine. The most common surgery for pancreatic cancer is pancreaticoduodenectomy, or Whipple procedure. Due to the friable nature of the pancreas, injury to the organ is easily incurred, which can cause complications during surgery; and, therefore, adequate retraction of surrounding tissue is essential.

Accordingly, the soft retractor 12 with a fiber-reinforced actuator 16 described herein is well suited for minimally invasive surgery. Use of a retractor 12 to retract the colon 40 to allow the surgeon to see and operate on the pancreas without causing any bleeding to the organ or the surrounding tissue is illustrated in FIGS. 9-12.

As illustrated in FIG. 9, a retractor 12 inserted through a trocar port 38. The soft actuator 16 is then inflated, safely conforming around the colon 40, as shown in FIG. 10. The colon 40 is then retracted, as shown in FIG. 11. A simulation of the retraction in-vitro is provided in FIG. 12, where, in a first step (top left), the soft actuator 16 is pushed against the colon 40. In a second step (top right), the soft actuator 16 is inflated to curl around the colon 40. In a third step (bottom left), a laparoscopic tool is used to lock the actuator 16 in place. In a fourth step (bottom right), the colon 40 is safely retracted by the retractor 12.

Exemplary Design Capabilities:

The soft retractor 12 can be configured to achieve the following performance standards for colon retraction and laparoscopic surgery: a) colon retraction: (1) able to lift 1,500 grams, (2) can maintain a stable grasp for 7-9 hours, (3) can be set up in less than 45 minutes, (4) can be repositioned in less than 10 minutes, (5) can be released from the colon 40 in less than 15 seconds, (6) conforms to the colon 40, and (7) distributes force evenly over large area so as not to damage the tissue; and b) laparoscopic surgery: (1) deployable through a 15-mm-inner-diameter trocar 38, (2) removable through a 15-mm-inner-diameter trocar 38, and (3) manipulatable by one manual or da Vinci laparoscopic tool (from Intuitive Surgical, Inc., of Sunnyvale California, US) post set-up.

In describing embodiments of the invention, specific terminology is used for the sake of clarity. For the purpose of description, specific terms are intended to at least include technical and functional equivalents that operate in a similar manner to accomplish a similar result. Additionally, in some instances where a particular embodiment of the invention includes a plurality of system elements or method steps, those elements or steps may be replaced with a single element or step; likewise, a single element or step may be replaced with a plurality of elements or steps that serve the same purpose. Further, where parameters for various properties or other values are specified herein for embodiments of the invention, those parameters or values can be adjusted up or down by l/100^th, l/50^th, l/20^th, l/10^th, l/5^th, l/3^rd, 1/2, 2/3^rd, 3/4^th, 4/5^th, 9/10^th, 19/20^th, 49/50^th, 99/100^th, etc. (or up by a factor of 1, 2, 3, 4, 5, 6, 8, 10, 20, 50, 100, etc.), or by rounded-off approximations thereof, unless otherwise specified. Moreover, while this invention has been shown and described with references to particular embodiments thereof, those skilled in the art will understand that various substitutions and alterations in form and details may be made therein without departing from the scope of the invention. Further still, other aspects, functions and advantages are also within the scope of the invention; and all embodiments of the invention need not necessarily achieve all of the advantages or possess all of the characteristics described above. Additionally, steps, elements and features discussed herein in connection with one embodiment can likewise be used in conjunction with other embodiments. The contents of references, including reference texts, journal articles, patents, patent applications, etc., cited throughout the text are hereby incorporated by reference in their entirety; and appropriate components, steps, and characterizations from these references may or may not be included in embodiments of this invention. Still further, the components and steps identified in the Background section are integral to this disclosure and can be used in conjunction with or substituted for components and steps described elsewhere in the disclosure within the scope of the invention. In method claims, where stages are recited in a particular order— with or without sequenced prefacing characters added for ease of reference— the stages are not to be interpreted as being temporally limited to the order in which they are recited unless otherwise specified or implied by the terms and phrasing.

Claims

CLAIMS What is claimed is:

1. A robotic retractor, comprising

an elongated handle;

a fiber-reinforced soft actuator mounted at an end of the elongated handle, wherein the soft actuator comprises:

a) an elongated elastomeric body that defines an inflatable chamber; b) a fiber reinforcement wrapped around the elongated elastomeric body; and

c) a strain-limiting layer extending along one side of the soft actuator, wherein the strain-limiting layer is configured to cause the soft actuator to bend toward the side of the strain-limiting layer; and a pump coupled in fluid communication with the inflatable chamber and configured to pump fluid into the inflatable chamber.

2. The robotic retractor of claim 1, further comprising a biocompatible sheath covering the elongated elastomeric body and the fiber reinforcement.

3. The robotic retractor of claim 1, wherein the soft actuator and the handle have dimensions of 15 mm or less orthogonal to the elongated axis.

4. The robotic retractor of claim 3, wherein the handle is 5-50 cm long.

5. The robotic retractor of claim 1, wherein the soft actuator has a hemi-circle- shaped cross-section with a straight side and a convex side, and wherein the strain-limiting layer is positioned along the straight side.

6. The robotic retractor of claim 1, further comprising a suction device coupled with an end of the soft actuator and detachably coupled with the handle and configured to generate a suction by which the soft actuator can be adhered to a surface when the suction device is detached from the handle.

7. The robotic retractor of claim 1, further comprising at least one magnet at an end of the soft actuator by which the soft actuator can be adhered to a surface.

8. The robotic retractor of claim 1, wherein the soft actuator further includes a latch at an end of the soft actuator opposite from where the soft actuator is mounted to the handle.

9. A method for retracting bodily tissue using a robotic retractor comprising an elongated handle and a fiber-reinforced soft actuator mounted at an end of the elongated handle, the method comprising:

using the handle to insert the soft actuator inside a body of an organism;

positioning the soft actuator alongside tissue to be retracted inside the body;

pumping fluid into the soft actuator, bending the soft actuator around the tissue to grasp the tissue; and

retracting the grasped tissue with the soft actuator to displace the grasped tissue.

10. The method of claim 9, wherein the organism is a human.

11. The method of claim 10, wherein the grasped tissue is a colon.

12. The method of claim 10 or 11, wherein the grasped tissue is displaced toward an inner wall of human skin.

13. The method of claim 12, wherein the tissue is displaced during a surgical operation.

14. The method of claim 9 wherein the soft actuator is inserted into the body through a trocar port.

5. The method of claim 9, wherein the soft actuator further comprises a strain- limiting layer along a side along which the soft actuator bends.