DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0064] I. Introduction and Environment

[0065] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.

[0066] II. Tissue Closure System 2

[0067] Referring to the drawings in more detail, the reference numeral 2 generally designates a tissue closure treatment system embodying the present invention. As shown in FIG. 1 , the system 2 is adapted for use on a patient 4 with an incision or wound 6 , which can be closed by a stitch line 8 consisting of sutures 10 , staples or other suitable medical fasteners.

[0068] A patient interface 12 consists of an optional deep drain 14 connected to a deep drain negative pressure source 15 associated with a deep drainage reservoir 17 and an external patient interface 16 including a primary fluid transfer component FTC. 1 comprising a strip of rayon or other suitable porous material, an underdrape 20 generally covering FTC. 1 and including a slot 20 a, a secondary fluid transfer component FTC. 2 comprising a hydrophobic sponge and an overdrape 24 .

[0069] A fluid handling subsystem 26 includes the deep drain negative pressure source 15 and a surface drain negative pressure source 28 , which can be combined for applications where a common negative pressure source and a collection receptacle are preferred. The negative pressure sources 15 , 28 can operate either manually or under power. Examples of both types are well-known in the medical art. For example, a manually operable portable vacuum source (MOPVS) is shown in U.S. Pat. No. 3,115,138, which is incorporated herein by reference. The MOPVS is available from Zimmer, Inc. of Dover, Ohio under the trademark HEMOVAC®. Bulb-type actuators, such as that shown in U.S. Pat. No. 4,828,546 (incorporated herein by reference) and available from Surgidyne, Inc. of Eden Prairie, Minn., can be used on smaller wounds, for shorter durations or in multiples. Moreover, power-actuated vacuum can be provided by vacuum assisted closure equipment available under the trademark THE VAC® from Kinetic Concepts, Inc. of San Antonio, Tex. Still further, many health-care facilities, particularly hospitals and clinics, are equipped with suction systems with sources of suction available at wall-mounted outlets.

[0070] A finite capacity reservoir 30 is fluidically connected to the negative pressure source 28 and is adapted to discharge to a waste receptacle 32 . A shut-off valve 34 is associated with the reservoir 30 and is adapted to automatically discontinue drainage when the reservoir 30 is filled to a predetermined volume.

[0071] An optional autotransfusion subsystem 36 can be connected to the deep drain 14 and is adapted for reinfusing the patient 4 with his or her own blood. U.S. Pat. No. 5,785,700 discloses such an autotransfusion system with a portable detachable vacuum source, which is available from Zimmer, Inc. and is incorporated herein by reference.

[0072] FIG. 2 shows an incision 6 forming first and second separated tissue portions 38 a,b with incision edges 40 a,b. The incision 6 extends from and is open at the skin 42 , through the deep dermal layer 44 and the subcutaneous layer 46 , to approximately the fascia 48 . A deep drain tube 50 is placed in a lower part of the incision 6 and penetrates the skin 42 at an opening 52 .

[0073] FIG. 3 shows the incision edges 40 a,b secured together by sutures 54 forming a stitch line 56 at the skin surface 42 . As an alternative to sutures 54 , various other medical fasteners, such as staples, can be used. FIG. 4 shows sutures 55 placed in the deep dermal layer 44 below the skin surface 42 .

[0074] FIG. 5 shows application of FTC. 1 on top of the stitch line 8 . FTC. 1 preferably comprises a suitable porous wicking material, such as rayon, which is well-suited for wicking the fluid that exudes along the stitch line 8 . Rayon also tends to dry relatively quickly, and thus efficiently transfers fluid therethrough. The underdrape 20 is placed over FTC. 1 and the adjacent skin surface 42 . Its slot 20 a is generally centered along the centerline of FTC. 1 and directly above the stitch line 8 . FTC. 1 and the underdrape 20 can be preassembled in a roll or some other suitable configuration adapted to facilitate placement on the stitch line 8 in any desired length. FIG. 6 shows FTC. 1 and the underdrape 20 in place.

[0075] The secondary fluid transfer component FTC. 2 is shown installed in FIG. 7 . It preferably comprises a suitable hydrophobic foam material, such as polyurethane ether (PUE), which comprises a reticulated, lattice-like (foam) material capable of being collapsed by vacuum force (negative pressure) in order to exert positive “shrink-wrap” type compression on skin surface and still maintain channels that allow passage of fluid. As shown, its footprint is slightly smaller than that of the underdrape 20 , thus providing an underdrape margin 20 b. The wicking layer of FTC. 1 can, as an alternative, be sized equal to or almost equal to the footprint of FTC. 2 . This configuration lends itself to prefabrication as an individual, pre-assembled pad that can be employed by simply removing a releasing layer backing from an adhesive lined underdrape. This configuration also lends itself to easy total removal and replacement of the central part of the assembly without removing drape already adhered to skin if removal and replacement is the desired clinical option rather then staged removal or prolonged single application.

[0076] FIG. 8 shows the overdrape 24 applied over FTC. 2 and the underdrape 20 , with a margin 24 a extending beyond the underdrape margin 22 b and contacting the patient's skin surface (dermis) 42 . FIGS. 9 and 10 show a patch connector 58 mounted on FTC. 2 and comprising a hydrophobic foam (PUE) material core 58 a sandwiched between drape layers 58 b. A vacuum drain tube 60 includes an inlet end 60 a embedded in the foam core 58 a and extends between the drape layers 58 b to an outlet end 60 b connected to the surface drainage negative pressure source 28 .

[0077] FIG. 1 a shows FTC. 3 removed, e.g. by cutting away portions of the overdrape 24 to provide an overdrape opening 54 . In addition, the overdrape 24 can be slit at 55 to further ventilate FTC. 2 . Draining FTC. 2 under negative pressure, and further drying it with air circulation ( FIG. 11 a ) can provide significant healing advantages by reducing the growth of various microbes requiring moist environments in FTC. 2 . Such microbes and various toxins produced thereby can thus be evaporated, neutralized and otherwise prevented from reentering the patient. Microbe control can also be accomplished by introducing antiseptics in and irrigating various components of the patient interface 12 , including the drapes 20 , 24 ; FTC. 1 ; FTC. 2 ; and FTC. 3 .

[0078] FIG. 11 b shows the patient interface 12 removed along underdrape perforated tear lines 56 and slit lines 59 in overdrape 24 . It will be appreciated that substantially the entire patient interface 12 , except for underdrape and overdrape margins 20 b, 24 a can thus be removed to provide access to the stitch line 8 and the dermis 42 for visual inspection, evaluation, cleaning, stitch removal, dressing change (e.g., with prepackaged patient interface 12 a as shown in FIG. 11 c ), consideration of further treatment options, etc. For example, the overdrape 24 can be slit to around the perimeter or footprint of FTC. 2 to permit removing the same. Preferably FTC. 2 is easily releasable from the underdrape 20 and FTC. 1 whereby FTC. 2 can be grasped and lifted upwardly to facilitate running a scalpel through the overdrape 24 and into a separation between the underside of FTC. 2 and the underdrape 20 . The FTC. 1 can then optionally be removed by tearing the underdrape 20 along its tear lines 56 and removing same as shown in FIG. 11 b.

[0079] FIG. 11 c shows a prepackaged patient interface 12 a adapted for initial or “dressing change” application. Optionally, the rayon strip FTC. 1 can have the same configuration or “footprint” as the foam sponge FTC. 2 , thus eliminating the underdrape 20 . The prepackaged patient interface 12 a can be sterilely packaged to facilitate placement directly on a stitch line 8 . Alternatively, the patient interface components can be prepackaged individually or in suitable groups comprising subassemblies of the complete patient interface 12 . For example, the underdrape/FTC. 1 and the overdrape/FTC. 2 subassemblies respectively can be prepackaged individually. Various sizes and component configurations of the patient interface can be prepackaged for application as indicated by particular patient conditions. Preferably, certain sizes and configurations would tend to be relatively “universal” and thus applicable to particular medical procedures, such as TJRs, whereby patient interface inventory can be simplified. Alternatively, the individual components can be assembled in various sizes and configurations for “custom” applications.

[0080] FIGS. 12 a - d show alternative connecting fluid transfer components FTC. 3 a - d for connecting FTC. 2 to the surface drainage negative pressure source 28 . FTC. 3 a ( FIG. 12 a ) shows a patch connector with a similar construction to FTC. 3 and adapted for placement at any location on the overdrape 24 . FTC. 3 a is provided with a Leur lock connector 62 . FTC. 3 b ( FIG. 12 b ) comprises a strip of hydrophobic (PUE) foam material partially covered by an overdrape 64 , which can be configured as a wrap around a patient's limb or extremity 66 . FTC. 3 c ( FIG. 12 c ) is an elbow-type connector. FTC. 3 d ( FIG. 12 d ) is a bellows-type elbow connector, which is adapted to accommodate deflection of the vacuum drain tube 60 .

[0081] FIGS. 12 e,f show an alternative construction of FTC. 2 a with multiple, removable wedges 57 formed therein and adapted for accommodating articulation, such as joint flexure. The flexibility of FTC. 2 a can thus be considerably enhanced for purposes of patient comfort, mobility and flexibility. Such wedges can extend transversely and/or longitudinally with respect to FTC. 2 a. FTC. 2 a functions in a similar manner with and without the wedges 57 in place or removed.

[0082] FIG. 12 g shows a modified patient interface 312 with the underdrape 20 placed below FTC. 1 . This configuration permits removing FTC. 1 without disturbing the underdrape 20 . FIG. 12 h shows a further modified patient interface 412 with FTC. 1 having the same configuration or footprint as FTC. 2 , whereby they can be fabricated and bonded together. In this configuration the underdrape 20 can be omitted.

[0083] III. Treatment Method

[0084] FIGS. 13 a - c comprise a flowchart for a method embodying the present invention. From start 70 the method proceeds to patient diagnosis and evaluation at 72 and treatment plan at 74 . Deep drains 14 are installed at 76 as necessary, and the incision is sutured at 78 . Surface interface components 12 are applied at 80 and connected to the external components (i.e., negative pressure sources 15 , 28 ) at 82 . The collection reservoir capacity is preset at 84 based on such factors as nature of wound/incision, blood flow, etc.

[0085] Phase 1

[0086] Deep drainage occurs at 86 and active surface drainage occurs at 88 , both being influenced by the negative pressure sources 15 , 28 . The negative pressure source 28 causes the PUE foam FTC. 2 to partially collapse, which correspondingly draws down the overdrape 24 and exerts a positive, compressive force on the closed wound or incision 6 . In the closed environment of the patient interface 12 , such force is effectively limited to ambient atmosphere. This limiting control feature protects the patient from excessive force exerted by the patient interface 12 . The steady force of up to one atmosphere applied across the closed wound or incision 6 functions similarly to a splint or plaster cast in controlling edema and promoting healing.

[0087] A “Reservoir Full” condition is detected at 90 and branches to an interrupt of the surface drainage negative pressure at 92 , after which the reservoir contents are inspected and disposed of at 94 . If surface bleeding is detected by visual inspection at decision box 96 , the method branches to a “Discontinue Active Surface Drainage” step at 98 . If the suture line is actively draining at decision box 100 , the method loops to the active surface drainage step 88 and continues, otherwise active surface drainage discontinues at 98 , i.e. when the wound/incision is neither bleeding nor exuding fluids.

[0088] Phase 1 is generally characterized by deep drainage (interactive or passive) and active surface drainage under the influence of manual or powered suction. The normal duration is approximately two to three days, during which time post-operative or post-trauma swelling normally reaches its maximum and begins to recede.

[0089] Phase 2

[0090] FIG. 13 b shows Phase 2 commencing with a “Staged Component Removal?” decision box 102 . An affirmative decision leads to independently deactivating and removing components at 103 , including discontinuing active suction at 104 , which transforms the hydrophobic PUE foam (FTC. 2 ) internal pressure from negative to positive and allows the collapsed FTC. 2 to reexpand at 106 , potentially increasing surface composite pressure from ambient to positive. Preferably this transition occurs without applying undue pressure to the surface from the decompressed, expanding FTC. 2 . During Phase 1, negative pressure (i.e., suction/vacuum) tends to compress FTC. 2 and correspondingly contracts the overdrape 24 , adding to the compression exerted by FTC. 2 . When the application of negative pressure discontinues, either manually or automatically, FTC. 2 re-expands against the constraints of the overdrape 24 , and in an equal and opposite reaction presses against the skin 42 , particularly along the stitch line 8 . FTC. 2 can thus automatically transform from ambient to positive pressure simply by discontinuing the application of the vacuum source.

[0091] The positive pressure exerted on the skin 42 continues to compress and stabilize tissue along the suture line 8 (step 108 ) in order to reduce swelling and cooperates with the operation of FTC. 1 and FTC. 2 to continue drainage by evaporation at the suture line 8 at step 110 . A negative determination at decision box 102 leads to interface removal at 112 and, unless treatment is to be terminated, stitch line inspection and treatment at 113 and interface replacement at 114 , which can involve all or part of the patient interface 12 . The method then proceeds to Phase 3.

[0092] Phase 3

[0093] FIG. 13 c shows Phase 3 of the treatment method wherein deep drainage is discontinued and the tube(s) is removed at 118 . The overdrape 24 and FTC. 2 are removed at 120 , 122 respectively. The underdrape 2 Q and FTC. 1 are preferably configured to permit visual inspection of the suture line 8 therethrough at 124 . When the suture line 8 has closed sufficiently, the underdrape 20 and FTC. 1 are removed at 126 and the treatment ends at 128 . Alternatively and if indicated by the patient's condition, all or part of the interface 12 can be replaced in Phase 3 and treatment continued.

[0094] IV. Alternative Embodiment Tissue Closure System 202

[0095] FIG. 14 schematically shows a tissue closure system 202 comprising an alternative embodiment of the present intention, which includes a microprocessor or controller 204 , which can be connected to one or more sensors 206 coupled to the patient interface 12 for sensing various conditions associated with the patient 4 . The microprocessor 204 can be programmed to operate a solenoid 208 coupled to a valve 210 associated with the reservoir 30 and controlling fluid flow induced by a negative pressure source 228 through its connection to the patient interface 12 .

[0096] FIG. 15 shows the tissue closure system 202 with the microprocessor 204 connected to multiple sensors 206 a,b,c each of which is associated with a flow control component, such as a valve, 210 a,b,c respectively. Each flow control component 210 a,b,c is associated with a respective negative pressure source 228 a,b,c, which in turn controls fluid discharge into canisters or reservoirs 212 a,b,c respectively. For example, the patient interface 12 can comprise an external patient interface 16 as described above and a pair of deep drainage tubes 50 a,b. The patient interface 12 includes an optional supply component 214 , which can comprise one or more fluid reservoirs, pumps (manual or powered) and associated controls, which can connect to the microprocessor 204 for system control. The supply component 214 optionally takes to one or more of the tubes 50 , 60 for delivering fluid to the patient through the deep drainage tubes 50 or through the external patient interface 16 . Such fluids can comprise, for example, antibiotics, and aesthetics, irrigating agents, growth factor, and any other fluid beneficial in promoting healing, countering infection and improving patient comfort.

[0097] The methodology of the treatment with the alternative embodiment tissue closure system 202 is shown in FIG. 16 and generally involves modified pretreatment 230 and Phase 1 procedures. From “Start” the method proceeds to a diagnosis/evaluation step 234 , a treatment plan step 236 , deep drain installation 238 , suturing at 240 , external interface component application 242 , microprocessor programming 244 and connection of the application components at 246 , such as connection of the tubing. Phase 1 commences with deep drainage at 248 , active suction interface at 250 and a “Suture Line Actively Draining?” decision box 252 . If the suture line is actively draining, the method loops back to the active suction interface step 250 , otherwise (negative determination at 252 ) it proceeds to Phase 2.

[0098] V. Applications

[0099] Without limitation on the generality of useful applications of the tissue closure systems 2 and 202 of the present invention, the following partial list represents potential patient conditions and procedures, which might indicate application of the present invention.

[0100] Over closed tissue separations, such as surgical incisions.

[0101] Over joints where the incision is subject to movement and stretching, such as arthrotomy, reconstructive proceedures, cosmetic procedures, flaps, scar revisions, Total Joint Replacement (TJR) procedures, i.e., hip, knee, elbow, shoulder and foot.

[0102] Any wound in an area of thick or unstable subcutaneous tissue, where splinting of skin and subcutaneous tissue might reduce dehiscence of deep sutures.

[0103] Wounds over reconstructive procedures in which irregular cavities are created. These include resection of tumors, implants, bone, and other tissues. Changes in length and geometry of limbs, and changes in size, position, and contour of bones and other deep structures.

[0104] Wounds in which elimination and prevention of dead space is important.

[0105] Treatment of hematomas and seromas.

[0106] Amputation stumps.

[0107] Abdominal, thoracic, flank, and other wounds in which splinting of the wound might assist closing and mobilizing the patient during the postoperative interval.

[0108] Wounds in areas of fragile or sensitive skin, where repeated removal and replacement of tape or other adhesives might produce pain, irritation, or blistering of skin in the vicinity of the wound. Also where dressing changes might produce shear or displacement of tissue so as to compromise primary wound healing.

[0109] Wounds in cases where the patient wishes to bathe before the skin has healed sufficiently to allow protection from contamination with bath or shower water.

[0110] Wounds subject to contamination with feces, urine, and other body fluids.

[0111] Pediatric, geriatric, psychiatric, and neurologic patients, and other patients likely to disturb dressings and wounds.

[0112] Patients with multiple consultants and care givers, where repeated inspection of the wound might compromise healing.

[0113] Deep closure and surface sutures and staples.

[0114] Any clean surgical or traumatic incision, open, or fully or partially closed by sutures, or where the skin edges can be apposed to a gap no wider than the width of the negative pressure zone of the dressing, i.e. where the maximum separation is less than or equal to the width of FTC. 1 (rayon strip).

[0115] In cosmetic and reconstructive surgery, the systems and methods of the present invention can control and conceal the effects of early bleeding, exudation, ecchymosis, and edema of the wound.

[0116] In surgery on the limbs, where compression and drainage by this method might eliminate or reduce the need for circumferential compressive wrapping.

[0117] Tissue separations that are prone to protracted drainage, such as hip and knee incisions, and tissue separations in patients with health conditions, such as diabetes, that tend to inhibit healing. Shortened hospital stays might result from swelling reduction and control of drainage.

[0118] VI. Case Studies

[0119] General concept: sequential surface application of foam material (FTC. 2 ) to surgical site and other wounds. Air-drying at the suture line is facilitated by the rayon strip (FTC. 1 ).

[0120] Phase 1: deep drainage (drain tube(s)), active or passive; active suction applied to surface PUE foam (placed on top of surgical incision, drains bleeding and exudate from suture line); active suction compresses PUE foam, thus applying positive compression to the entire dissection field; adhesive-lined film underdrape with an MVTR of 3-800 on skin underlying PUE foam; rayon (or other suitable porous wicking material) strip on suture line; similar type of adhesive film overdrape (MVTR of 3-800) overlying PUE foam material.

[0121] Duration: approximately 2-3 days, i.e. effective time for active drainage from incision/stitch line to cease and for suture line to dry and heal.

[0122] Phase 2: Remove active suction by cutting off (elbow) connector and leave FTC. 2 in place. Released from suction, FTC. 2 expands against the overdrape and exerts positive pressure differential on the operation site. May maintain continued mild compression throughout Phase 2; residual drainage function through rayon strip and into FTC. 2 provides continued drying of suture line. Deep drain tubes remain in place during Phase 2 for active deep drainage.

[0123] Duration: approximately three days, i.e. days 3-6 after operation.

[0124] Phase 3: remove overdrape and FTC. 2 ; leave underdrape and rayon strip in place; visually observe wound healing progress; transparency desirable.

[0125] Duration: several (e.g., up to three) weeks.

[0126] Clinical trial confirmation: Closure of surgical site in upper chest area in patient with severe healing problems showed excellent results and rapid wound healing.

[0127] Subcuticular (subepidermal) sutures avoid conflict with rayon strip and need for early suture removal, or pressure on skin sutures beneath compressive black sponge.

[0128] Option: use pressure transducer for interface pressure mapping of wound site and automate control and monitor pressures, flow, etc.

[0129] VII. Alternative Embodiment Tissue Closure System 302 .

[0130] A tissue closure system 302 comprising an alternative embodiment of the present invention is shown in FIGS. 17 - 22 . The system 302 is adapted for closing a wound 304 with an undermined area 306 just above the fascia and an upper tissue separation 308 located primarily in the dermis and in the subcutaneous layer. A wedge-shaped internal fluid transfer component (foam piece) 310 is located in the tissue separation area 308 and is installed between side drapes 312 located on either side of the wound 304 . An external fluid transfer component (foam piece) 314 is placed on top of the internal component 310 and the side drapes 312 , and is covered by an outer drape 316 . An optional innermost foam piece 330 can be located in and sized to fit the undermined area 306 and can transfer fluid and gradient forces to and from the internal foam piece 310 .

[0131] A reclosable access panel 318 is placed over an opening formed in the outer drape 316 and includes an adhesive-coated perimeter 320 surrounding an adhesive-free center area 322 with a reclosable seal strip 324 extending longitudinally down the centerline thereof. The seal strip 324 includes a rib or bead 326 , which is releasably captured in a channel 328 ( FIG. 20 ).

[0132] In operation, the reclosable access panel 318 is adhesively secured around its perimeter 322 to the outer drape 316 and provides access to the foam pieces 310 , 314 of the dressing system 302 . For example, the foam pieces 310 , 314 can be changed ( FIGS. 21 and 22 ), treatments can be applied and wound healing progress can be visually monitored.

[0133] VIII. Alternative External Dressing 402 .

[0134] FIGS. 23 - 27 show an external dressing 402 , which can be premanufactured or preassembled and used for various wound treatment and closure applications. The dressing 402 includes a foam piece 404 partially enclosed in a rayon covering 406 , which includes an open top 408 secured to an upper perimeter 410 of the foam piece 404 , for example, by sutures, staples, adhesive or some other suitable mechanical fastener as shown at 412 . The dressing 402 is preferably preassembled with an outer drape 414 including a foam-covering central portion 416 and a perimeter, patient-contact skirt portion 418 . A tucked margin 420 is formed at the intersection of the drape portions 416 , 418 and partially underlies the foam piece 404 in order to protect the skin and prevent the formation of low-pressure, vacuum voids around the edge of the foam piece 404 whereat blistering could otherwise occur. In operation, the dressing 402 can be easily changed by cutting around the margin 420 , removing the foam piece 404 and the drape outer portion 416 . The wound can thus be inspected, cleaned, debrided, treated, etc. and a new dressing 402 put in place. The patient-contact skirt portion 418 of the original dressing can remain in place.

[0135] FIG. 23 shows a fluid flow (discharge) directional arrow 421 from an elbow coupling 417 and a discharge tube 419 . Alternatively, fluid could be injected into the dressing 402 through the tube 419 and the coupling 417 . Hydraulic/pneumatic compressive force arrows 423 are shown in FIG. 23 and represent the downward (i.e. into patient) forces, which can be established by compressing the foam piece 404 under suction and then releasing the negative pressure differential, thus transitioning the dressing to a positive pressure differential. In a positive pressure differential mode of operation, the dressing 402 controls edema by pressing the foam piece 404 against the tissue adjacent to the wound. There are many potential medical benefits from controlling edema in this manner. For example, healing is promoted, scar tissue is minimized and patient discomfort can be reduced.

[0136] FIG. 24 shows the external dressing 402 used in conjunction with an internal foam piece 422 , which is located below the dermis at the top of the subcutaneous layer. The internal foam piece 422 is adapted for applying a pressure differential within the subcutaneous layer whereby tissue growth and closure are promoted. The inside/outside configuration of the dressing system shown in FIG. 24 can rehabilitate and make pliable a wound edge 424 that has contracted and become hard, immobile and edematous by applying pressure differentials across the external and internal foam pieces 404 , 422 , such as compression (positive pressure differential) for edema control.

[0137] FIG. 25 shows the wound confined to the dermis 426 with another internal foam piece 428 in place. The subcutaneous layer is substantially healed. FIG. 26 shows the external foam piece 404 in place alone for drawing the wound edges 430 together at the epidermis. FIG. 27 shows the external foam piece 404 covered on the sides and bottom by the rayon covering 406 , leaving an open top 408 .

[0138] IX. Alternative Embodiment Dressing System 502

[0139] FIG. 28 shows yet another alternative embodiment internal/external dressing system configuration 502 with an external foam piece 504 similar to the foam piece 404 described above and an internal foam assembly 506 located in the dermis and in the subcutaneous layer. The assembly 506 consists of a proximate internal foam piece 508 , which can be located at the bottom of the subcutaneous layer on top of the fascia in an undermined cavity 510 formed by the wound, and a distal internal foam piece 412 located primarily in the dermis and the subcutaneous layer portions of the wound between the external foam piece 504 and the proximate internal foam piece 508 .

[0140] The dressing system configuration 502 can be configured and reconfigured as necessary to accommodate various wound configurations in various stages of healing. For example, the proximate internal foam piece 508 can be removed when the undermined cavity 510 closes. Likewise, the distal internal foam piece 512 can be removed when the subcutaneous layer and the dermis have healed. Moreover, the foam pieces 504 , 508 and 512 can be replaced with different sizes of foam pieces as necessary in connection with dressing changes and as the wound configuration changes. Such sizes and configurations can be chosen to optimize the beneficial effects of pressure gradients (both positive and negative), fluid control, edema control, antibacterial measures, irrigation and other treatment protocols. Still further, the access panel 318 described above can be used in conjunction with the dressing system 502 in order to provide access to the foam pieces thereof and to the wound itself.

[0141] FIG. 29 shows the internal/external dressing system 502 compressed under the vacuum effects of an external vacuum source with the drape 316 drawn tightly down on the compressed outer foam piece 504 . Thus compressed, the system 502 is adapted to transfer positive pressure differential, compressive forces to the area of the wound.

[0142] X. Alternative Embodiment Dressing Assembly 602

[0143] FIGS. 30 - 37 show a reclosable, preassembled external dressing assembly 602 comprising an alternative embodiment of the present invention. The dressing assembly 602 includes a foam piece 604 , which can be completely covered in rayon 606 or some other suitable material with the desired absorbent and/or wicking capabilities. The foam piece 604 also includes a core 605 comprising a suitable material, such as polyurethane, hydrophobic foam. Alternatively, other foam materials with hydrophobic or hydrophilic properties can be utilized. Various sizes and shapes of the foam piece 604 can also be employed, including cutting and trimming it to size during the course of a medical procedure.

[0144] The foam piece 604 is removably placed in a reclosable sheath 608 including a bottom panel 610 selectively covered by removable, adhesive backing strips 612 , 614 and 616 forming a central opening 618 . As shown in FIG. 31, a central opening 618 in the bottom panel 61 0 is initially covered by the center backing strip 614 . Removing the center backing strip 614 exposes the foam piece 604 through the opening 618 . The reclosable sheath 608 also includes a top panel 620 with a reclosable seal strip 622 extending from end-to-end and generally longitudinally centered. The seal strip 622 can be similar in construction to the reclosable seal strip 324 described above. The top panel 620 also includes fluid ports 324 , 326 , which can comprise, for example, Leur lock connectors or some other suitable fluid connection device.

[0145] The sheath 608 can comprise polyethylene or some other suitable material chosen on the basis of performance criteria such as permeability, flexibility, biocompatibility and antibacterial properties. Various permeable and semi-permeable materials are commonly used as skin drapes in medical applications where healing can be promoted by exposure to air circulation. The sheath 608 can be formed from such materials for applications where continuous vacuum suction is available and the dressing 602 is not required to be airtight.

[0146] According to an embodiment of the method of the present invention, a dressing assembly 602 can be premanufactured, or custom-assembled from suitable components for particular applications. In a premanufactured version, the dressing 602 is preferably presterilized and packaged in sterile packaging.

[0147] A common application of the dressing 602 is on a recently-closed surgical incision for controlling bleeding and other fluid exudate. For example, the dressing 602 can be placed on the patient with its bottom panel opening 618 located over a stitch line 636 ( FIG. 36 ). The center backing strip 614 is peeled from the bottom panel 610 to expose the opening 618 and the adhesive 628 on the bottom panel 610 ( FIG. 33 ). The opening 618 provides a fluid transfer, which can also be provided by constructing the sheath bottom panel 610 from a permeable material, or by providing other passage configurations therethrough. The dressing 602 can then be placed on the patient, with the bottom panel adhesive providing temporary fixation. The side backing strips 612 , 616 can then be removed, as shown in FIG. 32 , and the bottom panel 610 completely secured to the patient.

[0148] The fluid ports 624 , 626 are adapted for either extraction or infusion of fluids, or both, depending on the particular treatment methodology. For extraction purposes a vacuum source can be attached to one or both of the ports 624 , 626 , and can comprise a mechanical, powered pressure differential source, such as wall suction. Alternatively, hand-operated mechanical suction can be provided, such as a suction bulb 630 ( FIG. 33 ) or a Hemovac device available from Zimmer Corp. of Warsaw, Ind. Such hand-operated suction devices can accommodate patient mobility and tend to be relatively simple to operate. Powered suction and fluid pump devices can be preprogrammed to provide intermittent and alternating suction and infusion, and to automatically respond to patient condition feedback signals. As shown in FIG. 33 , the application of a negative pressure differential (suction) collapses the sheath 608 onto the foam piece 604 . The various dynamic fluid forces and fluid movement effects described above can thus be brought into operation and controlled.

[0149] FIG. 34 shows the sheath 608 further collapsing on the foam piece 604 as a result of evacuation from both of the fluid ports 24 , as indicated by the fluid flow arrows 632 . The ambient air pressure force arrows 634 show the application of this force, which tends to collapse the sheath 608 onto the foam piece 604 .

[0150] FIG. 35 shows opening the seal strip 622 for access to the interior of the dressing 602 . The foam piece 604 can then be removed, as shown in FIG. 36 , whereby the stitch line 636 can be visually inspected and/or treated. The foam piece 604 can be flipped over or replaced, as necessary. FIG. 37 shows a cross-section of the foam piece 604 , which can be completely covered in rayon or some other suitable wicking material 606 in order to accommodate placement of either side against the stitch line 636 .

[0151] XI. Alternative Embodiment Dressing Assembly 702

[0152] FIGS. 38 - 40 show a dressing assembly 702 comprising an alternative embodiment of the present invention and including a foam piece 704 comprising any suitable hydrophobic or hydrophilic foam material. The foam piece 704 is selectively and removably located in a sheath 708 , which can be similar to the sheath 608 described above. A liner 706 can comprise a piece of rayon or some other suitable material adapted to wick fluid from the stitch line 636 into the foam piece 704 , and further adapted to isolate the patient from direct contact with the foam piece 704 . The liner 706 can be sized to lay flat against the bottom panel of the sheath 708 .

[0153] In operation, the dressing assembly 702 is adapted to utilize readily available components, such as the foam piece 704 and the liner 706 , in a dressing adapted for wound inspection, wound treatment and component change procedures, all without having to remove the sheath or disturb its adhesive attachment to the patient. FIG. 39 shows removing the foam piece 704 , which can be flipped over for reuse or replaced. FIG. 40 shows removing the liner 706 , which can also be easily replaced. With the liner 706 removed, the stitch line 636 is exposed for stitch removal, inspection, treatment, irrigation and other procedures. The sheath 708 can then be reclosed and vacuum-assisted and/or other treatment can resume.

[0154] XII. Alternative Embodiment Dressing Assembly 802

[0155] A dressing assembly 802 comprising an alternative embodiment of the present invention is shown in FIG. 41 and includes a foam piece 804 in a sheath 806 adapted for opening and closing through a reclosable seal strip 808 . The sheath 806 includes an upper drape portion 810 , which can comprise a suitable semi-permeable or impervious drape material. The sheath 806 includes a perimeter 812 , which can be provided with an optional adhesive perimeter seal 813 adapted for providing a relatively fluid-tight seal around the sheath 806 . The perimeter seal 813 can be relatively narrow in order to minimize patient discomfort, skin maceration, etc. A bottom panel 814 comprises a suitable wicking material, such as rayon, and extends to the sheath perimeter 812 . The materials comprising the dressing 802 can be chosen for permeability or occlusiveness, biocompatibility, hydrophobic or hydrophilic reaction to liquids, bacteriastatic and antimicrobial properties, and other performance-related properties and criteria.

[0156] In operation, the dressing 802 is placed on the patient over a wound or stitch line. The perimeter adhesive 813 can provide temporary fixation and sealing. A strip of tape 816 can be placed over the sheath perimeter 812 for securing the sheath 806 in place. Fluid is transferred through the wicking material layer 814 to the foam piece 804 for evacuation through suitable fluid connectors, as described above, which can be attached to a vacuum source. Moreover, the dressing 802 is adapted for providing a positive pressure gradient, also as described above. The seal strip 808 permits access to the foam piece 804 for flipping over or changing, as indicated.

[0157] The foam piece 804 , the drape upper portion 810 and the wicking material layer 814 can be assembled for independent movement whereby the only attachment among these components occurs around the perimeter 812 where the drape upper portion 810 is connected to the wicking material layer 814 . Such independent freedom of movement permits the dressing assembly 802 to reconfigure itself and conform to the patient and various applied forces, such as pressure gradients. The individual components can thus expand and contract independently of each other without distorting the other components or interfering with the performance and comfort of the dressing assembly 802 .

[0158] It is to be understood that while certain embodiments and/or aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments/aspects.