METHOD AND USE

[0001] FIELD OF THE INVENTION

[0002] The present invention relates generally to surgical drapes and more particularly to surgical drapes for use in image-guided surgery or procedures.

[0003] BACKGROUND OF THE INVENTION

[0004] Over one million CT-guided biopsies are performed per year in the U.S. There are two million ultrasound-guided biopsies a year. Many of these ultrasound biopsies are performed because computerized tomography ("CT") is not available. Ultrasound is also traditionally faster than CT, as there is the availability of substantially real time imaging. Traditionally, CT required the acquisition of an image, the passage of a needle, the acquisition of another image and the repositioning of the needle to be checked by acquisition of another image. With this process a biopsy could take hours and it was hard to keep track of the needle tip relative to the patient and know if it was necessary to angle up or down to get to the target.

[0005] The recent availability of CT fluoroscopy has radically changed management of patients. With CT fluoroscopy, cross sectional images of the body are obtained which are refreshed up to thirteen times a second. Further increases in the refresh rate are believed by the inventors to be a reasonable expectation. With some CT scanners, three slices can be presented

simultaneously, all being refreshed thirteen times a second. This can create a substantially flicker-free image of a needle or device being passed into the patient. This has the potential to increase speed, accuracy and ability to safely deliver needles to sensitive or delicate structures and avoid large blood vessels.

[0006] However, there are drawbacks and limitations to CT fluoroscopy. One of these is that CT scanners are typically used to capture images and are non-sterile. Therefore, under CT image guidance procedures, elaborate sterilization can be necessary to reduce risk of patient infection. Simplified sterilization techniques are therefore desirable. It is therefore an object of the invention to provide a sterile drape for image-guided surgical procedures that obviates or mitigates the above-identified disadvantage of the prior art. [0007] SUMMARY OF THE INVENTION

[0008] Accordingly, the invention provides, in accordance with a first aspect, a sterile drape which is releasably attachable to an imaging machine having a gantry, the gantry having a tunnel and a patient table. Examples of such imaging machines include CT scanners, MRI machines and the like. The drape is adapted to provide a sterile barrier between an inner surface of the tunnel above and to each side of a patient table, and comprises, consists essentially of, or consists of:

a. a sterile flexible sheet having a front edge, a rear edge, and a pair of opposed side edges extending between the front and rear edges; b. at least one front attachment member configured to releasably attach at least a portion of the front edge of the flexible sheet to the imaging machine at one side of the tunnel; c. at least one rear attachment member configured to releasably attach the rear edge of the flexible sheet to the imaging machine at the other side of the tunnel; wherein the flexible sheet is dimensioned so that when the flexible sheet is so attached to the imaging machine, the flexible sheet covers the inner surface of the tunnel above and to each side of the patient table.

[0009] A variety of attachment members can be used including fasteners chosen from single- sided tape, double-sided tape, low-tack adhesive, a collapsible and expandable spring-like element, and combinations thereof. The spring-like element can have any variety of shapes in side profile (or in elevation) and in cross-section. In terms of side profile or elevation, the spring-like element can be semi-circular, semi-oval or semi-rectangular. In terms of cross- section, the spring-like element can be circular, rectangular, or oval, or combinations thereof. The shape and dimensions are, at least in part, selected to allow the spring-like element to expand and engage the imaging machine on either side of the tunnel.

[0010] The spring-like element can be a flexible and resilient rod affixed to the flexible sheet proximate to and extending along the front and rear edges of the flexible sheet. The flexible rod can be dimensioned in order that the drape can be placed inside the tunnel and the rods can be expanded to cause portions of the flexible sheet proximate the front and rear edges of the sheet to engage the imaging machine at either side of the tunnel. Additional fasteners, such as single- sided tape, double-sided tape, or the like can be used to improve the attachment of the rod to the imaging machine.

[0011] The rod can be made of any material that is flexible, resilient and has a "memory," i.e. a tendency to return to an expanded and natural shape but be deformable into a more compact shape or state. For example, the rod can be made of a material that can be folded during storage and expanded under action of a radial force to assume a U-shaped configuration.

Suitable materials for use in making the rod will be apparent to the skilled person, and include certain types of plastics, metal, carbon fiber, and combinations thereof. An example of a metal that can be used is Nitinol, available from Nitrol Devices and Components, 47533 Westinghouse Drive, Fremont, CA 94539. Metal is to be avoided for drapes intended for use with MRI machines but can be used for other drapes, e.g. those for use with other machines such as CT scanners.

[0012] In some embodiments, the rod is contained in tubular retainers formed one at each edge of the flexible sheet, by folding the front and rear edges of the sheet towards a middle of the sheet and affixing the front and rear edges to the sheet.

[0013] In some embodiments, the flexible sheet can be made of plastic such as a material chosen from polypropylene fabrics, polyethylene fabrics, and combinations thereof. The sheet can further be clear, translucent, or opaque. When translucent or opaque, the sheet can be made in a variety colors such as blue, green or other colors.

[0014] When attachment members are in the form of a low-tack adhesive, such as the adhesive used in products such as POST-IT NOTES™, the low-tack adhesive may be present on an entire one side of the flexible sheet, or on portions thereof as spaced-apart bands of adhesive.

[0015] Whether or not low-tack adhesive is used, the flexible sheet of the sterile drape can be formed into rolls of sheets, with perforations between adjacent sheets to permit separation of one sheet from an adjacent sheet in the roll.

[0016] In accordance with a second aspect, the invention provides a sterile drape in

accordance with the first aspect, mounted to an imaging machine that has a gantry, the gantry having a tunnel and a patient table. At least a portion of the front edge of the sheet is releasably attached to the imaging machine at one end of the gantry, and at least a portion of the rear edge of the sheet is releasably attached to the imaging machine at the other end of the gantry. When so mounted, the sterile flexible sheet provides a sterile barrier between an inner surface of the tunnel above and to each side of the patient table.

[0017] When rods are used as attachment members, the imaging machine can comprise front and rear funnels each comprising a retainer configured and dimensioned to releasably retain a respective one of the rods of the drape, whereby the flexible sheet can be placed inside the tunnel and the rods expanded and made to engage the retainers and be releasably attached thereto. The retainers are shaped and dimensioned to releasably retain the rods and can be in the form of an arcuate lip shaped to conform to the shape of the rod.

[0018] In accordance with a third aspect, the invention provides a new use of a sterile sheet in providing a sterile barrier between an inner surface of a gantry tunnel of an imaging machine above and to each side of a patient table.

[0019] A fourth aspect of the invention provides a method of providing a sterile barrier between an inner surface of a gantry tunnel of an imaging machine above and to each side of a patient table, the method comprising providing a drape according to the first aspect, and mounting the drape to an imaging machine with the flexible sheet of the drape forming an arcuate shape above the patient table and extending through the gantry tunnel, e.g. between the front and rear ends of the gantry tunnel.

[0020] In accordance with a fifth aspect of the invention, there is provided a sterile flexible sheet for use in providing a sterile barrier between an inner surface of a gantry tunnel of an imaging machine above and to each side of a patient table, the sheet being dimensioned so that it can be attached to the imaging machine to cover the inner surface of the tunnel above and to each side of a patient table.

[0021] In accordance with a sixth aspect of the invention, there is provide a kit of parts comprising a sheet or drape according to the invention, the kit of parts comprising other items for use in a surgical procedure, such as a biopsy needle.

[0022] Drapes and flexible sheets according to the invention can have a simple structure, be made at low cost, be easy to deploy for use, and easy to collapse into a compact configuration prior to deployment and after use. The drapes and flexible sheets can be disposable or re- sterilized for re-use. [0023] BRIEF DESCRIPTON OF THE DRAWINGS

[0024] The invention may be better understood with reference to the following detailed description and drawings in which,

[0025] Figure 1 is a perspective view from a front and left side of an imaging machine, i.e. a CT scanner, with a patient lying on a patient table and a surgeon shown performing a procedure on the patient;

[0026] Figure 2A is a perspective view from a front and left side of a flexible sheet of a drape in accordance with a first embodiment of the invention;

[0027] Figure 2B is a perspective view from a front and left side of the CT scanner of Figure 1 , and the drape comprising the flexible sheet of Figure 2 mounted thereto using single-sided tape (the patient and surgeon are removed to show more details of the mounting);

[0028] Figure 2C is a front elevation view of the CT scanner and drape of Figure 2B;

[0029] Figure 2D is a side sectional view of the CT scanner and drape of Figure 2B;

[0030] Figure 3A is a perspective view from a front and left side of a drape according to a second embodiment of the invention, mounted on the CT scanner using double-sided tape;

[0031] Figure 3B is a side sectional view of the drape and CT scanner of Figure 3A;

[0032] Figure 4 is a perspective view from a front and left side of a drape in accordance with a third embodiment of the invention comprising a flexible sheet to which is applied a low-tack adhesive on one side thereof;

[0033] Figure 5A is a top view of a drape according to a fourth embodiment of the invention comprising a flexible sheet to which is applied a low-tack adhesive on one side thereof in spaced apart columns;

[0034] Figure 5B is a top view of a drape according to a fifth embodiment of the invention comprising a flexible sheet to which is applied a low-tack adhesive on one side thereof in spaced apart rows;

[0035] Figure 5C is a top partial view showing the drape of Figure 5A as part of an expanded roll of drapes;

[0036] Figure 6A is a side sectional view of the CT scanner of Figure 1 , to which is mounted a drape according to a sixth embodiment of the invention comprising a flexible sheet, rod and double-sided tape;

[0037] Figure 6B is an enlarged partial view of that portion of Figure 6A denoted by reference numeral 6B;

[0038] Figure 7A is a front elevational view of the CT scanner of Figure 1 to which is mounted a drape according to a seventh embodiment of the invention comprising a flexible sheet, rod and single-sided tape;

[0039] Figure 7B is a side sectional view of the CT scanner and drape of Figure 7A;

[0040] Figure 7C is an enlarged partial view of that portion of Figure 7B denoted by reference numeral 7C;

[0041] Figure 8A is a front elevational view of the CT scanner of Figure 1 to which is mounted a drape according to an eighth embodiment of the invention comprising a flexible sheet and rod only;

[0042] Figure 8B is a side sectional view of the CT scanner and drape of Figure 8A;

[0043] Figure 8C is an enlarged partial view of that portion of the CT scanner and drape of Figure 8B denoted by reference numeral 8C in Figure 8B;

[0044] Figure 8D is a side sectional view of a modified CT scanner comprising an arcuate retainer lip in which is seated the rod of the drape of Figure 8A; and

[0045] Figure 9 is a schematic drawing of a kit of parts comprising a drape according to the invention.

[0046] DETAILED DESCRIPTION OF EMBODIMENTS

[0047] When used herein, terms denoting orientation, e.g. front, rear, side, above, below, columns, rows, etc. are used for convenience and with reference to the drawings. The intention is not to claim the invention in any particular orientation, and it will be appreciated that the invention can assume other orientations, other than as shown, described, and claimed. The claims shall not be construed so as to limit the invention to any particular orientation.

[0048] The term "comprising" means including the recited integers or elements and any additional integers or elements not expressly recited.

[0049] The term "consisting of" means including only the recited elements or integers and no additional integers or elements, unless the context clearly dictates otherwise. [0050] The term "consisting essentially of" means including the expressly recited integers or elements and such additional integers or elements as would not materially affect the basic and novel properties of the invention, such being the ability to provide a substantially sterile barrier between the inner surface of a gantry tunnel and above and to each side of a patient table of an imaging machine.

[0051] Referring now to the drawings, Figure 1 shows a surgeon 10 performing a procedure on a patient 12 lying on a patient table 13 under image guidance using, in this example, a CT scanner 14. As best seen with reference to Figure 2D, the CT scanner 14 has a gantry 16 with two ends. A front funnel 18 is at one end, and a rear funnel 20 is at the other end. The gantry 16 also has a tunnel 22 which extends between the front and rear funnels 18, 20. The risk of contamination caused by the surgeon 10 touching an inner surface 26 (Fig. 1) of the tunnel 22 above and to each side of the patient table 13 is significant. To avoid contamination, a sterile drape 28 can be releasably attached to the CT scanner 14 as is shown in Figures 2B, 2C, and 2D to provide a sterile barrier between the inner surface 26 of the tunnel 22 and a space above and to each side of the patient table 13.

[0052] This is achieved by releasably affixing a sterile flexible sheet 30 (best shown in Figure 2A) to the tunnel 22. As shown in Figure 2A, the sheet 30 has front and rear edges 32, 34 and a pair of opposing side edges 38, 40 extending between the front and rear edges 32, 34. The sheet 30 is attached to the tunnel 22 by attaching the front and rear edges 32, 34 to the front and rear funnels 18, 20 respectively of the gantry 16, using attachment members in the form of single-sided tape 36 (Figs. 2B, 2C, and 2D).

[0053] Accordingly, CT scanner 14 can now be used in a sterile or substantially sterile manner. When the use of CT scanner 14 is completed, drape 28 can simply be disassembled therefrom by substantially reversing the above-described assembly steps, and then disposed of, or re- sterilized, as desired.

[0054] The sheet 30 is dimensioned, that is, the lengths of the front, rear, and side edges 32, 34, 38, and 40 are selected, so that the sheet 30 can be mounted to the CT scanner 14 to provide a sterile or substantially sterile barrier between the inner surface 26 of the tunnel 22 and a space above and to each side of the patient table 13. By covering the inner surface of the CT scanner tunnel 22 that may be touched by a surgeon or a patient, the sheet 30 allows a sterile environment to be achieved to reduce risk of contamination and infection. [0055] Alternative embodiments of the invention are depicted in the subsequent figures wherein like reference numerals are used to denote like parts. Figures 3A and 3B show a drape 46 similar to the drape 28 except that double-sided tape 48 is used instead of single-sided tape to attach the sheet 30 to the CT scanner 14.

[0056] Figure 4 shows an embodiment of a drape 50 consisting of a sterile flexible sheet 52 having front and rear edges 56, 58. The sheet is made of polypropylene fabric and low-tack adhesive 54 applied to an entire one side thereof. The adhesive 54 replaces the single and double-sided tape in the embodiments described above and can be used to attach an entire one side of the sheet 52 to the tunnel 22.

[0057] Figures 5A and 5B depict further alternative drapes 53, 55 comprising sterile flexible sheets 57, 59, respectively. The low-tack adhesive 54 can be present on portions of the sheets 57, 59 as spaced-apart bands of adhesive 54. As shown in Figure 5C, the sheet 57 can be present in a roll (not shown) of a plurality of flexible sheets 60, the roll comprising perforations 62 between adjacent sheets 57 thereby, permitting separation of one sheet from an adjacent sheet in the roll 60.

[0058] Figures 6A and 6B depict a further embodiment of a drape 64 comprising a sterile flexible sheet 66 made of clear polyethylene fabric and attachment members in the form of double-sided tape 48 and a collapsible and expandable spring-like element in the form of flexible and resilient plastic rods 68, 70 that spring or bow outwardly (expand radially) to cause the drape 64 to assume a somewhat semi-cylindrical shape with an outer profile that is complementary to an inner profile of the tunnel 22 of the gantry 16. Thus, the drape 64 can be placed inside the gantry tunnel 22 with each rod 68, 70 on either side of the tunnel 22 and automatically expanded to cause the front and rear edges 72, 74 of the sheet 66 to indirectly engage the front and rear funnels 18, 20 the gantry 16, respectively, to provide a sterile barrier in the upper portion of the tunnel 22. It will be appreciated that, prior to and after use, the drape 64 can assume a compact, collapsed configuration for ease of handling and space efficiencies.

[0059] As best seen with reference to Figure 6B (though not completely shown), the rods 68, 70 are contained in tubular retainers 76, 78, formed one at each edge 72, 74 of the flexible sheet 66. The tubular retainers 76, 78 are formed by folding the front and rear edges 72, 74 of the sheet 66 towards a middle of the sheet 66 and affixing the front and rear edges 72, 74 to the sheet 66 by (in this embodiment) adhesive. [0060] As shown in Figures 7A, 7B and 7C, single-sided tape 36 can be used instead of double- sided tape 48. Alternatively, depending on the degree of flex provided by the rods themselves, there need not be any adhesive or tape used at all, as shown in Figures 8A, 8B, and 8C.

[0061] Referring to Figure 8D, the front and rear funnels 18, 20 of the CT scanner 14 can be modified to include retainers 76, 78 configured and dimensioned to releasably retain a respective one of the rods 68, 70, whereby the sheet 66 can be placed inside the tunnel 22 and the rods 68, 70 expanded and made to engage the retainers 76, 78 and be releasably attached or mounted thereto. In this embodiment, the retainers 76, 78 each are in the form of an arcuate lip having a shape conforming to the shape of the rods 68, 70 to facilitate retention of the rods 68, 70 thereon.

[0062] The drapes and/or sheets according to the present invention can be pre-sterilized and then folded for storage (all the while maintaining sterility) within a sterile packaging. The sterile packaging is not opened until the drape or sheet is put into use, and only then opened under acceptable and/or desirable sterile conditions.

[0063] Referring to Figure 9, a kit of parts 80 (shown schematically) comprising a drape 82 according to the invention and biopsy needle 84 is shown. The drape 82 and biopsy needle 84 are for use in a surgical procedure such as a biopsy conducted under an imaging examination. The drape 82 and biopsy needle 84 are contained in sterile compartments 86, 88, respectively of a package 90. Though not shown, other articles for use in the surgical procedure may be included in the package such as surgical gloves, a surgical gown, etc. and the package 90 can be modified to accommodate these additional items.

[0064] While only specific combinations of the various features and components of the present invention have been discussed herein, it will be apparent to those of skill in the art that desired subsets of the disclosed features and components and/or alternative combinations of these features and components can be utilized, as desired.

[0065] Furthermore, numerous modifications can be made to the embodiments described above. For example, the drape can be used in a variety of imagining machines that have gantries such as MRI machines, CT scanners, gamma ray machines, and the like. The springlike elements or rods of the drape can be made of a variety of different materials other than plastic that function to be outwardly springed or to bow out, including metal, carbon fiber, and combinations thereof. However, if made of metal, then the drape would not be useful in MRI machines for which the use of metal is prohibited.

[0066] To facilitate or improve engagement of the drape to the inner surfaces of the tunnel of a gantry, additional spring-like elements can be added along the length of the drape. To avoid interference with the x-rays, the elements positioned inside the tunnel should be made of plastic or some other material that will not appear under an imaging beam. Furthermore, alternative or additional attachment members can be used to enhance attachment of the side edges or front and rear edges of the sheet to the patient table or inner surface of the tunnel, such as single- sided tape, double-sided tape, low-tack adhesive, Velcro™, ties, snaps, hooks and loops, ties, and the like. These attachment members can be positioned along and proximate to the front, rear and/or side edges of sheets according to the invention.

[0067] The material of the sterile flexible sheet can be varied provided that the material does not interfere with the imaging beam. In some embodiments, the sheet can be made of high quality polyethylene fabric. The sheet can also be packaged and/or sold separately or together with the attachment members.

[0068] It will now be understood that the sheet or drape and imaging machine are

complementary to each other. Thus, the various components and dimensions of the sheet or drape are chosen to correspond with the complementary parts on the imaging machine. Thus, for example, the rods 68, 70 will have a curvature and diameter that is complementary to the curvature and diameter of the funnels 18, 20 and the sheet width (length of the front and rear edges) will be sized to match the size of the tunnel (or gantry aperture). Ideally, the sheet width will be slightly greater than ½ the circumference of the gantry tunnel. In this way, the drape will not substantially reduce the diameter of the tunnel 22 after assembly. The length of the side edges of the sheet will correspond to the length or depth of the tunnel. It will be appreciated that the side edges will have a length that exceeds the length of depth of the tunnel by about 10 to about 20 cm to provide end portions that can attach to the gantry outside of the tunnel (e.g. to the gantry front and rear funnels).

[0069] The sheet can also be constructed in different shapes and sizes to complement different configurations, shapes and sizes of imaging machines. For example, the sheet can have one end that is closed and an opening at an opposite end depending on the type of imaging machine with which it is to be used.

[0070] For example, a head CT scanner can have a gantry tunnel diameter of about 12.5 inches (about 31.8 cm) and a gantry tunnel length or depth of about 17.2 inches (about 43.6 cm). Other CT scanners can have gantry tunnel diameters that are about 33.5 inches (85 cm) and a tunnel length or depth of about 27 inches (68.5 cm). A commercially available combined CT scanner and PET scanner has a gantry tunnel that is about 187 cm in length (depth). Most CT scanners have diameters that range from about 30 to about 100 cm, about 50 to about 90 cm, about 60 to about 85 cm, or about 70 to about 85 cm. The average diameter of a common type of CT scanner is about 70 cm, or about 72 cm, and up to about 78 cm. Therefore, the front and rear edges of the sheet can have lengths ranging from half the circumference of the gantry tunnel plus about 10 to about 20 cm. That is, the front and rear edges of the sheet can independently be up to about 180, 165, 155, 145, 140, 130, or 120 cm in length. Furthermore, the length of the front and rear edges of the sheet can independently be from about 55, 85, 105, or 115 cm, and up to about 260, 240, 220, and 200 cm. Combinations of these values and all values in between are expressly contemplated herein.

[0071] The length (or depths) of the tunnels of gantries can range from about 40 to about 2000 cm, and can be about 96, 125, 150, 173, 185, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 and 1000 cm. Therefore, the length of the side edges of the sheet can range from about 60 to about 2040, or from about 100 to about 1040 cm. It can also be about 106, 126, 146, 166, 186, 206, 226, 520, 540, 560, 580, 600, 620, 640, 660, 680, 700, 720, 740, 760, 780, 800, 820, 840, 860, 880, 900, 920, 940, 960, 980, 1000, 1020, or 1040 cm.

[0072] The sheet need not be rectangular, or if it is rectangular, it need not be a perfect rectangle and can have front and rear edges that are wider than the width of the sheet at a location between the front and rear edges.

[0073] Furthermore, the location of the retainers on the imaging machine need not necessarily be limited to the respective distal ends (front and rear ends) of the machine but need only result in the ability to assemble the drape or sheet to the machine while leaving a suitable and appropriately substantially sterile passageway within tunnel. In another variation of the foregoing, the drape or sheet can be made of a rigid material, or an outwardly springed material to allow the drape to attach to the machine.

[0074] Numerous other modifications to the embodiments described above can be made within the scope of the invention herein described and claimed below.