Patent Application
20080021362
While the specification concludes with claims which particularly point out and distinctly claim the invention, it is believed the invention will be better understood from the following description taken in conjunction with the accompanying drawings illustrating some non-limiting examples of the invention. Unless otherwise indicated, the figures are drawn to scale and like reference numerals identify the same elements.
In this embodiment the distal ring (10) is circular with a circular cross-sectional geometry; however, non-circular rings and non-circular cross-sectional geometries are also possible. For instance, the distal ring could have a oval or elliptical in cross-sectional shape. The distal ring (10) can be made from a variety of different materials with different characteristics. In this example the distal ring is made from an elastomer such as polyurethane, polyethylene, silicone, and the like. The distal ring can also vary in size. For instance, the distal ring can have an inside diameter greater than 1 inches and less than 9 inches, and a thickness less than 1 inch, but dimensions outside these ranges are also possible. Optionally, the distal ring (10) will have a durometer between 40A and 90A or 70D, but other material properties are also possible.
In this embodiment the sleeve (20) is a single layered tube of material; however, a discontinuous sleeve or multi-layered sleeves are also possible. The sleeve (20) can be made from a variety of variety of different materials with different characteristics. In one example, the sleeve (20) is made from an elastomer such as polyisoprene, silicone, polyurethane, silicone, and the like; however, inelastic materials such as mylar could also be used. The sleeve (20) may be clear, transparent, translucent, or opaque. As shown here, the sleeve (20) is fastened at its ends directly to the proximal and distal rings using an adhesive or heat sealing techniques; however, alternative techniques may also be employed. The sleeve (20) could also be attached to the rings at locations other than the sleeve ends. For instance, the sleeve (20) can wrapped around the distal ring (10) and adhesively attached or sealed to itself. The length of the sleeve (20) can also vary. For instance, the sleeve may be between 2 cm and 20 cm in length; however, other lengths are also possible. The thickness of the sleeve (20) can also vary. For instance, the sleeve thickness in this embodiment is between 0.010 and 0.020 inches; however, other thicknesses are also possible.
In this embodiment the proximal ring (30) is circular; however, non-circular rings are also possible. The proximal ring (30) can also vary in size. For instance, the proximal ring (30) can have an inside diameter between 1 and 9 inches, but other dimensions are also possible. Optionally, the ratio of the distal ring (10) and proximal ring (30) diameters is greater than 0.4. The proximal ring (30) in this example has a tricuspidate cross-sectional geometry. In this embodiment, the cross-sectional geometry is substantially constant around the circumference of the proximal ring (30). A geometry is substantially constant if any variations are insignificant. For example, geometric variations resulting only from molding or other manufacturing factors would be considered substantially constant. Also in this embodiment the cross-sectional geometry is substantially solid; however, holes or cavities may also be present.
In this example the proximal ring (30) rolls in resting increments of 360 degrees. In other words, when the ring rolls it “snaps” between resting positions. Optionally, the flip force for the proximal ring (30) can be less 10 in*lbs/180 degrees of rotation, and can be less than 3 in*lbs. Flip force is a way of measuring the force required to roll the ring about itself. The flip force is measured at room temperature on a stand-alone proximal ring without the sleeve attached. An equal and opposite torque is applied simultaneously to a ring at two diametrically opposite points along the circumference of the ring. The peak measured torque to roll the ring is used to calculate the flip force. By compiling 100 peak measured torques for a given ring, the statistical median value is the flip force. Preferably, the flip force is substantially the same for each sequential resting incremental rotation. Optionally, the proximal ring (30) may have substantially no residual hoop stress. One way to achieve this is through a molding process where the proximal ring (30) is injection molded and transfer molded using a thermoplastic or thermoset elastomer such as polyisoprene, silicone, polyurethane, silicone, and the like. In one embodiment, the proximal ring is molded from Desmopan 9370. The proximal ring (30) may have a durometer between 50A and 50D, but other material properties are also possible.
The proximal ring (100) includes a circumferential cavity (107), shown in this example having three crooks aligned with each cusp (101, 103, 105). A biasing member (108), such as a full or partial ring made from an elastomer or metal, is positioned in medial crook of the cavity (107). As the proximal ring (100) is rolled, the biasing member (108) will leave the medial crook and track the surface of the cavity (107). The biasing member will also circumferentially expand, thus inducing a hoop stress on the biasing member (108). After the proximal ring (100) is rolled more than 60 degrees, the biasing member (108) will tend to relieve the hoop stress and “snap” to the next crook and rotate that crook to the medial position. Thus, proximal ring (100) rolls in resting increments of 120 degrees.
One way to make the proximal ring (100) involves extruding a length of material with the desired cross-sectional geometry, bending the length into a ring and inserting the biasing member (108) into the cavity (107), and then fastening the ends of the length together using a coupling and/or fastening techniques (e.g., adhesives, heat welding, ultrasonic welding, and the like). Optionally, the assembled proximal ring (100) may be heat cured to reduce hoop stresses induced during the bending step.
Preferably, the wound protectors described above will be processed before surgery. First, a new or used wound protector is obtained and if necessary cleaned. The wound protector can then be sterilized. In one sterilization technique the wound protector is placed in a closed and sealed container, such as a plastic or TYVEK bag. Optionally, the wound protector can be bundled in the container as a kit with other components, including one or more of the following: a sealing cap to maintain pneumoperitoneum, a sealing cap with a valve to allow passage of surgical instruments or a surgeon's arm while maintaining pneumoperitoneum (e.g., iris valve, gel seal, cuff, and the like), a tube of lubricant, a mounting ring in which the proximal ring may be seated and to which a cap can be attached, a marker, an incision template or scale, an instruction sheet, and the like. The container and wound protector, as well as any other components, are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation kills bacteria on the wound protector and in the container. The sterilized wound protector can then be stored in the sterile container. The sealed container keeps the wound protector sterile until it is opened in the medical facility.
The wound protectors described above can be used as a stand-alone device, for instance in open surgical procedures, or in combination with a cap having sealing valve for endoscopic instruments or a surgeon's arm. Among other advantages, the foregoing examples provide effective wound protection to prevent infection and facilitate wound retraction. Because the sleeve rolls-up, its length can be adjusted by the surgeon for any given anatomy and patient. Further, the surgeon can select the amount of retraction desired for a given procedure. The cross-sectional shapes of the proximal ring are easy to grip thus facilitating ease of use. Furthermore, the flip forces are relatively low and constant, further facilitating ease of use.
Having shown and described various embodiments and examples of the present invention, further adaptations of the methods and devices described herein can be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the specific materials, dimensions, and the scale of drawings will be understood to be non-limiting examples. Accordingly, the scope of the present invention should be considered in terms of the following claims and is understood not to be limited to the details of structure, materials, or acts shown and described in the specification and drawings.
