Body canal intrusion instrumentation having bi-directional coefficient of surface friction with body tissue

[0002] This is a continuation-in-part of my copending application of the same title: Ser. No. 08/989,413 filed Dec. 12, 1997 now abandoned.

[0003] This invention relates to instrumentation for invading body canals non-destructively and with a minimum of trauma, and more particularly it relates to the interface between the instruments and body tissue during dynamic ingress and egress of surgical instrumentation into the canals.

[0004] It has been the direction of the prior art to fashion surface structure of instrumentation for non-destructive invasion of body canals with very slippery surface structure to facilitate ingress and this accordingly produces low friction upon egress.

[0005] In the parent application, which is incorporated herein in entirety by reference, however it is disclosed that the ingress of the instrumentation into a desired body site has been facilitated by introduction of novel instrumentation surface structure having a bi-directional coefficient of friction with engaged tissue within the cavities and canals that they navigate. In this manner the naturally occurring peristalatic contractions may advantageously grasp and carry the instrumentation toward its desired work site, significantly decreasing the risks of puncture and significantly decreasing the surgeon's time for entry of instruments to desired work sites in such procedures as small bowel enteroscopy where an endoscope enters the esophagus passing through the stomach to be placed at work sites in the small intestine. Greater friction upon egress is supplied by microscopic or macroscopic surface texture that does not discomfort the patient or inflame the interfacing body tissue upon egress.

[0006] Thus, it has been discovered that significant advantages are afforded by such improved instrumentation surfaces with differential surface friction upon ingress and egress. Such advantages are realized, for example, in the surgical process of feeding such instrumentation into the tortuous, angulated and loosely fixated structures of the body tissue along the body canals through which the instrumentation must be fed. For example, in the case of small bowel enteroscopy an endoscope is fed from the esophagus and through the stomach into the intestines where the distal end must be manipulated to confront curves and folds in the small intestine and corresponding changes in travel direction. With the bi-directional coefficient of friction provided by this invention, the natural peristaltic waves of the body that carry food through this path are engaged to more easily find and traverse the right path through the stomach and the curves and folds of the intestines. It would be impossible to use the peristaltic waves with the slipperiness of the conventional instrumentation of the prior art which has the same coefficient of friction in ingress and egress directions.

[0007] The instrumentation to which this invention is directed comprises catheters, guide wires and medical instruments generally employed for dynamic movement into and out of body canals to internal body work sites, which are also employed at times for inspection of the condition of the canals. The modified instrumentation surfaces of this invention thus function in the dynamic ingress and egress through body canals. Thus, the surface structure is fashioned to expedite dynamic entry and withdrawal as distinguished for example from held in position stents providing the stent device with anchoring barbs resisting egress, typically shown in R. P. Gibbons U.S. Pat. No. 3,938,529, wherein the barbs resist movement of the stent both inwardly and outwardly and to avoid damage to body tissue and discomfort of the patient require for the stent to be confined during insertion and inserted through a cystoscope or like instrument into the work site wherein the barbs firmly engage the body tissue lock the stent into a permanent resident and stationary internal body position.

[0008] Accordingly it is an objective of this invention to provide improved medical devices for dynamic entry into work sites along body canals to support corresponding improved surgical methods facilitating the ingress of body intrusion instrumentation to those worksites and egress retrieval therefrom without trauma or inflammation of the canal body tissue interfacing with the inserted instrumentation.

[0009] A more specific objective of this invention is to provide preferred embodiments of the instrumentation surface structure provided by this invention with differential surface friction characteristics in the ingress and egress directions of movement of such character that trauma and inflammation of the canal body tissue is avoided during the dynamic movements.

[0010] Body invasion instrumentation afforded by this invention for ingress and egress into and out of body canals toward internal work sites must be manipulated with little inflammation and discomfort to body tissue at the interface between the instruments and body tissue during ingress and egress of the instrumentation. For this reason the prior art has introduced ways to make surfaces of such instrumentation slippier to avoid any improved kind of barbs or roughness. However this invention relates explicitly to improved methods of surgical exploration in inserting the instrumentation that reduces the need for probing which could inflame or puncture the canal walls. Thus, the instrumentation counters that trend to make instrumentation surfaces slipperier to the extent of providing modified instrumentation surfaces that have a differential friction upon ingress and egress.

[0011] The structure for achieving the differential friction property employs microscopic or macroscopic sized surface texture patterns that may be inserted and removed from internal body worksites with little discomfort or inflammation of interfacing body tissue. The preferred structures provide appropriate non-toxic materials of desirable flexibility to navigate body canals with tortuous and angulated paths thereby to withstand the scrutiny of good medical practice and sterility. The instrumentation includes some throw away after single use instruments such as guide wires and catheters as well as instruments that need to be sterilized and reused such as endoscopes. In general it has been found that certain plastics with treated exterior surfaces for providing bi-directional texture are advantageous, and that removable adhesive tapes or elastic sheaths may be disposably used for endoscopes, for example.

[0012] This leads to significantly improved surgical procedures for ingress into a work site deep inside the body. In particular the surgeon can control movement of the instrumentation into the worksite with the help of peristaltic propagation normally exerted by the patient's body. Thus, the differential surface friction feature will cause the instrumentation to naturally flow along the body canals and cavities such as the stomach to navigate desired openings such as the duodenum and small or large intestines, to facilitate movement along tortuous, angulated and loosely fixated body tissue paths. This decreases the possibility of puncture, and saves a considerable amount of the time a surgeon employs in manipulating the instrumentation to an interior body worksite.

[0013] Preferred embodiments of producing the bidirectional coefficient of surface friction upon the instrumentation surface are presented with features that facilitate surgical manipulation of the instrumentation and improve the surgeon's proficiency. The instrumentation is of the type including catheters, guide wires or cables, endoscopes and other associated instruments for performing medical and surgical procedures at internal body worksites.

[0014] Other features, objects and advantages of this invention will be found throughout the following description and claims and in the appended drawings.

[0015] In the accompanying drawings, wherein like reference characters in the different views relate to similar features to facilitate comparison,

[0016] FIG. 1 is a side view sketch of a catheter fragment with a specific surface geometry pattern that provides the bi-directional surface friction in the ingress and egress directions of the catheter which characterizes this invention,

[0017] FIGS. 2 and 3 are section views of further catheter embodiment fragments of the invention identifying different surface geometry patterns,

[0018] FIG. 4 is a side view sketch of a further catheter fragment embodiment of the invention providing bi-directional friction by selective application of a lubricant surface such as a hydrophilic plastic coating,

[0019] FIG. 5 is a side view sketch of a removable plastic sleeve embodiment of the invention that may envelop an endoscope, for example,

[0020] FIGS. 6 to 8 are different section view fragments of adhesive plastic film embodiments of the invention having different surface geometry patterns,

[0021] FIG. 9 is a perspective view of a section of adhesive film embodiment of the invention, with a tapered cross section configuration contributing to the bi-directional friction characteristics upon ingress and egress,

[0022] FIG. 10 is an end view in section of another tapered adhesive film embodiment of the invention,

[0023] FIGS. 11 and 12 are end view sketches of further tapered adhesive film embodiments of the invention,

[0024] FIGS. 13 and 14 are side view sketches of further embodiments of the invention with surface geometry patterns disposed in spiral patterns along the ingress-egress axis of the instrumentation,

[0025] FIG. 15 is a side view sketch of a section of guide wire embodying the invention,

[0026] FIG. 16 is an end view sketch of an oval shaped guide wire section of a further embodiment of the invention, and

[0027] FIG. 17 is a side view sketch illustrating an embodiment of the invention with an oval guide wire within a catheter having mating screw threads arranged in a spiral configuration for automatically rotating the oval guide wire as it advances through the catheter.

[0028] For the surgical procedures described in more detail in the parent application, a line of simply manufactured and thus inexpensive body intrusion instruments encompassing the characteristic bi-directional surface friction surface structure of this invention are herewith disclosed. These structures are thus grasped by the interface body tissue in the canals in which they are inserted employing naturally caused peristaltic wave action, such as swallowing, moving from the stomach into the duodenum or movement along the intestinal tract, for facilitating ingress in view of a relatively impeding surface friction characteristic in the egress direction. For example, significant advantages are thus afforded in the art of small bowel enteroscopy where the instruments are inserted into the esophagus for moving to a work site in the small intestine. These advantages include less time for the insertion process and deeper insertion with a smaller chance of puncture or trauma to the interfacing canal body tissue.

[0029] In general the differential surface friction characteristics may be imparted in several ways, such as directionally roughening the surface by embossing, engraving, molding, brushing, tapering, wrapping or overlapping layers to expose edges, or selectively decreasing friction in one direction on suitable surface structure by lubrication, as will be more fully described hereinafter with respect to different embodiments of the invention. Furthermore some of the embodiments favor rotation of the instrumentation as it dynamically moves in and out of the body canal. For example, a spiral pattern of surface texture may favor rotation by the surgeon during ingress and egress of an instrument, or a guy wire may be fed through a catheter tube as facilitated by internal catheter screw-like structure that automatically rotates the guy wires as they are longitudinally moved into or out of a work site. The rotation feature is particularly important in order to navigate the tortuous and angulated ingress paths along the body canals and to distinguish loosely fixated body tissue at the interface with the distal end of the instrument.

[0030] The texture of the surface structure providing the differential in friction for ingress and egress of the instrumentation in general may fall into a range from microscopic to macroscopic. However the frictional surface texture is not barbed nor sized large enough to cause discomfort to a patient or inflammation to the interfacing body tissue in the canals. In that respect the scale of the following embodiments is in general exaggerated in order to show the preferred structural texture pattern details. In general the plastics and/or metallic basic materials, films and adhesives that pass the sterility and compatibility requirements for guide wires, catheters and instrumentation for surgical intrusion into the body canals and provide the appropriate elasticity and rigidity are well known in the present state of the art, and this invention is directed to the feature of obtaining its characteristic bi-directional surface friction advantages.

[0031] As seen in FIG. 1, the surface texture of a cylindrical catheter 101 may be milled, cast or otherwise deformed to produce the ridges 102 and tapers 103 which provide a differential friction for movement in the ingress direction 104 and the opposing egress direction. These instruments being modified are typically the conventional cylindrical plastic bodies now available in the art. FIGS. 2 and 3 show different surface texture patterns for corresponding catheters 105 and 106. Also in FIG. 1, there is a progressive decrease in the height of the ridges creating a tapering of bi-directional friction.

[0032] As seen from the FIG. 4 catheter 107, the bi-directional friction differential is established by a hydrophylic polymer coating 108 on the ingress side of the bulbeous protrusions formed in the catheter body. This polymer coating on catheter, as well known in the art makes the coated surface of the catheter slipperier. In the embodiment of FIG. 5, the sheath 110 employs a bi-directional surface texture 111, which may be obtained for example by brushing or milling the surface of a polymer such as polyiden to give the generally macroscopic bi-directional characteristic.

[0033] In general at least part of the instrumentation afforded by this invention is inexpensive and may be disposable, such as catheters or guide wires dedicated to a single exploratory use before discarding. However if a reusable instrument such as an endoscope used for colonoscopy is employed the nature of the surface texture need be either disposable as a separate unit or of a nature that is readily cleaned and sterilized after use. Thus, the FIG. 5 sheath 110 represents an elastic condom-like disposable surface cover for the endoscope that imparts the bi-directional differential friction characteristic unique to this invention.

[0034] The invention also may be characterized by adhesively applied and therefore disposable surface structure represented by the various surface films 112, 113, 114 of respective FIGS. 6-8, having in common an adhesive coating 115 adapted to retain the bi-directional surface film removably upon the outer surface of a conventional bodily intrusion instrument. These films may be of a surface modified version of a thin semi-stretchable plastic.

[0035] As seen from the respective embodiments 116-119 of FIGS. 9-12, the body of the film strips shown may be tapered. As shown in FIG. 9, ingress is facilitated and egress is impeded by the trailing ridge structure 120. Additionally as shown in FIG. 10 the upper tapered surface may be coated with a lubricant surface 108, or may also contain surface textures as shown in FIGS. 11 and 12 which produce greater differential coefficients of friction in the ingress and egress directions.

[0036] In the FIG. 13 embodiment, the instrument embodiment 125 has a film strip 126 spiral wrapped in an overlapping fashion to provide at the overlapped ridge 127, which together with its tapered trailing edge 128 embody a frictional component that produces a bi-directional surface friction characteristic in the ingress and egress directions. This spiral ridge 127 also provides structure for aiding the surgeon to rotate the instrument 125 in opposite directions that respectively aid the ingress and egress of the instrument from a body cavity. The embodiment 130 of FIG. 14 provides the spiral wrapping feature with the non-overlapped spiral pattern of the adhesive film strip 131 provided with a bi-directional surface texture pattern.

[0037] FIG. 15 represents guide wire embodiment 135 of the invention, which as seen from the end view of FIG. 16 is preferably of oval shaped cross section. This feature, as illustrated by FIG. 17, wherein the catheter 140 has internal screw-like threads, internally rotates the oval shape guy wire 135 automatically as it progresses from its minor axis position 142 to its major axis position 143.

[0038] It is therefore seen that this invention provides various embodiments of the bi-directional surface structure of this invention, which embodiments are adaptable to a wide range of applications in different body canals for unexpectedly saving the surgeon's time and reducing the risks of body tissue damage with inexpensive adaptations of the body intrusion instrumentation with bi-directional coefficients of friction in the ingress and egress directions characteristic of this invention.

[0039] Accordingly those features of novelty encompassing the spirit and nature of this invention are defined with particularity in the appended claims.