Mechanical breakup unit for biochemically reactive fluid...

Details Mechanical breakup unit for biochemically reactive fluid... Mechanical breakup unit for biochemically reactive fluid...

2000-09-26

2004-12-28

Chin, Christopher L. (Department: 1641)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

Reexamination Certificate

active

06835186

ABSTRACT:

TECHNICAL FIELD
This invention relates to a mechanical breakup unit (MBU) for atomizing biochemically reactive fluids, and more particularly, a MBU in a medical fluid delivery device for separately atomizing fibrinogen and thrombin contained in separate containers to form fibrin on a surface.
BACKGROUND ART
One of the major problems in intra-abdominal surgery is the avoidance of post-operative adhesions. It is well-known that adhesions contribute to pain, immobility, retarded wound healing, and in particular to intestinal obstruction which may even be life-threatening. In the field of gynecological surgery, post-surgical adhesions involving female reproductive organs may result in infertility.
Each surgical procedure necessarily produces various forms of trauma where the abdominal cavity or other human cavity is opened. Physiologically, the process of wound closure then starts when bleeding ceases upon formation of a hemostatic clot at the areas of blood vessel injury. The clot, at first comprising mainly platelets, is solidified by a natural fibrin network resulting from the activation of an enzyme cascade involving thrombin, factor XIII and calcium. Further steps on the way to the sealing of the wound are retraction of the hemostatic clot, invasion of various cell types including fibroblasts into the wound area and eventually the lysis of the fibrin network. Adhesions are thought to begin forming when the fibrin clot covering an injury comes into contact with an adjacent surface and the new connective tissue produced by the fibroblasts attaches the two surfaces together.
This sometimes painful condition may often require a further operative procedure for removing/lysing the adhesions, called adhesiolysis, which, like the first operation, introduces the risk of forming additional adhesions.
Accordingly, the prevention of adhesion formation is medically important. Among the different approaches for prevention of adhesion formation, one involves the use of materials as a physical or bio-mechanical barrier for the separation or isolation of traumatized tissues during the healing process. Both synthetic materials and natural materials have been used as a barrier to adhesion formation. Some permanent inert implants, like GoreTex® surgical membranes consisting of expanded polytetra-fluoroethylene (PTFE) generally require a second operative procedure to remove them, while others, such as surgical membranes of oxidized regenerated cellulose, are biodegradable but are thought to elicit an inflammatory response ultimately leading to adhesion formation (A. F. Haney and E. Doty,
Fertility and Sterility,
60, 550-558, 1993).
Fibrin sealants/glues are well-known in the art for use in hemostasis, tissue sealing and wound healing, and have been commercially available outside the United States for more than a decade. Fibrin glues have not been used for anti-adhesion purposes. Further, the practice of changing the concentrations of thrombin and fibrinogen to achieve a fibrin film having a desired pore size has also not been practiced.
Fibrin glues mimic the last step of the coagulation cascade and are usually commercialized as kits comprising two main components. The first component is a solution comprising fibrinogen and factor XIII, while the second component is a thrombin calcium solution. After the mixing of components, the fibrinogen is proteolytically cleaved by thrombin and thus converted into fibrin monomers. Factor XIII is also cleaved by thrombin into its activated form (FXIIIa). FXIIIa cross links the fibrin monomers to form a three-dimensional network commonly called “Fibrin Gel.”
Previous attempts to provide a thrombin and fibrinogen delivery device are known. For example, one such device is disclosed in U.S. Pat. No. 4,978,336 to Capozzi et al. which discloses a dual syringe system. A device made by the assignee of the '336 patent, Hemaedics, Inc., is sold under the tradename DUOFLO. The distal end of each syringe is attached to a common manifold having a mixing chamber. Fibrinogen and thrombin solutions are mixed in the manifold 14 prior to application to a wound or other surface. The manifold has a discharge tip for delivering the mixed solution onto a surface. A shortcoming of this device is the propensity for the tip to clog with solid fibrin being formed during brief interruptions in the application process—such interruptions are common in medical procedures. The likelihood of this occurring increases as the thrombin concentration increases especially thrombin concentrations of greater than 20 IU/ml. The '336 patent acknowledges the clogging problem and suggests solving the problem by replacing the clogged tip. (Col. 3, line 4-Col. 4, line 2). However, replacing clogged tips is impractical and unacceptable for minimally invasive surgeries where a cavity of an animal body is accessed through a small surgical opening.
Other techniques teach applying beads of a solution of thrombin and calcium adjacent in contact with a solution of fibrinogen and Factor XIII on a surface. In such a case, the thrombin and fibrinogen react primarily along interfacing surfaces while the remaining portions of the solutions are generally isolated from one another by the solid fibrin formed between them. Thus, there is inadequate mixing of the solutions to provide for a suitable fibrin film. Further, the unreacted fibrinogen is now available to react with thrombin supplied by the body to promote the formation of adhesions.
U.S. Pat. No. 4,631,055 discloses another thrombin and fibrinogen delivery device having two syringes mounted in a holding frame in a parallel spaced relationship. A conical portion of a distal end of each syringe is inserted into a connecting head. In one embodiment of the '055 patent, mixing of fluids contained in each syringe occurs inside the connecting head and in another embodiment the mixing of the fluids occurs outside the mixing head. The connecting head also includes a channel to supply medicinal gas under pressure. The medicinal gas contacts the fluids at a mouth of the connecting head and conveys the fluids contained in the syringes to a surface.
Product literature commenting on a dual syringe device for delivering fibrinogen and thrombin and sold by the assignee of the '055 patent, reports that the device operates at gas pressures of about 30-65 psi. If such devices are not properly used, the momentum of the pressurized gas, especially when conveying entrained fluids, could cause damage to tissue being treated by this device.
Two known devices in the prior art are disclosed in U.S. Pat. Nos. 5,368,563 to Lonneman et al. and 5,582,596 to Fukunaga et al. The '563 patent discloses a large sprayer assembly in FIGS. 1-9 having a lateral feed conduit connecting two syringe connections to two mechanical breakup units. The syringes may contain separately a solution of fibrinogen and a solution of thrombin which are mixed to produce fibrin. The '563 patent does not concern itself, however, with the possibility of unreacted fibrinogen. Further, due to the lateral feed requirements of the disclosed device, laparoscopic use of the preferred embodiment of the sprayer assembly device shown in FIGS. 1-9 is not possible. In fact, FIG. 10 teaches an alternate embodiment, showing the invention in conjunction with, for example, a catheter for possible laparoscopic procedures. In the alternate embodiment the spray assembly using the MBU is replaced with an intermediate plate 94 having multiple fluid paths (96, 98, 100, and 102) and a sprayer plate 104 with exit ports 106 and 108. The exit ports 106 and 108 are disclosed as analogous to the ports 72 and 74 of the MBU sprayer assembly (FIG. 9). However, the disclosed laparoscopic embodiment lacks the spin chamber, sloped walls, and other dimensional requirements provided by the present invention to achieve the proper circumjacent spray pattern of the two fluids, thereby substantially eliminating the occurrence of unreacted fibrinogen.
Likewise, the '596 patent relates to a dual fluid applicator assembly.

Affiliated with

Also associated with

Rating

Mechanical breakup unit for biochemically reactive fluid... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Mechanical breakup unit for biochemically reactive fluid..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mechanical breakup unit for biochemically reactive fluid... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3305417