Microwave coaptive surgical sealing tool

A coaptive surgical sealing tool may be similar to an ordinary hemostat with long (50, 60, 70 or 80 mm) thin jaws for sliding into the liver parenchyma, without tearing the larger blood vessels. The jaws are spring loaded and are designed for uniform compression, and to avoid closing too quickly. The jaws are capable of sealing a 50, 60, 70 or 80 mm sealing length, in a single bite, although it can also seal shorter lengths as well. The tool can be used with existing ablative therapy microwave generators. The tool may be provided with irrigation and/or suction.

BACKGROUND OF THE INVENTION

Removal of part of the liver (hepatic resection) is often performed to remove a tumor. Blood loss is a serious complication associated with this procedure. Multiple surgical techniques and devices have been developed to minimize blood loss and improve outcomes in hepatic resection. Several studies including a 2009 Cochrane Systematic Review of techniques for liver parenchymal transection have examined the efficacy of different methods of liver resection. Based on this review, the clamp-crush technique was favored due to low cost and with newer techniques such as cavitron ultrasound surgical aspirator (CUSA), hydrojet, and radio frequency dissecting sealer (RFDS) showing no improvement in morbidity or blood transfusion in comparison to the clamp-crush technique.

The clamp-crush technique generally involves crushing the liver parenchyma using a hemostatic clamp tool to expose small vessels and biliary radicals, which are then divided and sealed via radio frequency (RF) energy provided to the jaws of the tool. Various tools have been proposed for this purpose. However, challenges remain in providing a coaptive surgical sealing tool offering superior performance and efficiency in a simple and low-cost design. It is an object of the invention to provide an improved coaptive surgical sealing tool

DETAILED DESCRIPTION OF THE DRAWINGS

A coaptive surgical sealing tool may be similar to an ordinary hemostat with long (50, 60, 70 or 80 mm) thin jaws for sliding into the liver parenchyma, without tearing the larger blood vessels. The jaws are spring loaded and are designed for uniform compression, and to avoid closing too quickly. The jaws are capable of sealing a 50, 60, 70 or 80 mm sealing length, in a single bite, although it can also seal shorter lengths as well. The tool can be used with existing RF/bi-polar cautery generators, including generators the Triad-Covidean Ligasure Generator, the ConMed generator or the Enseal generator. The tool is suitable for open surgery uses, and may also be adapted for laparoscopic surgery. The tool may be provided in different sizes for different caliber of vessels. In view of its simple design, the tool may be supplied at low cost, as either a reusable or single use unit.

In use, the jaws may be closed with a gradual compression process, with a compression spring acting against the closing movement, to prevent tearing of larger blood vessels. The jaws may a slot and/or ridge, to leave a pre-grooved line for transection after the seal has been completed. The tool may reduce parenchymal transection times in excess of 50%. With 55 mm or more of sealing length it can seal more tissue in one bite than any existing device yet it is also versatile enough to seal small lengths of tissue.

As shown inFIG. 1, an example of the tool10has first and second arms12and14pivotally connected via a hinge16. A finger ring18is provided on the back or proximal end of each arm12,14. Each arm12,14has a jaw24in front or distal of the hinge16. A spring26urges the jaws into an open position. A lock tab20may be provided adjacent to each finger ring18, to allow the jaws24to remain clamped or closed, against the force of the spring. The tool10according is similar to a hemostat clamp, and consequently benefits from ergonomic design elements of a hemostat clamp. Hence the tool10provides ease of use when used in open surgery. Connectors22may connect electrodes30on the jaws24to an RF generator.

The jaws24are very thin and easy to slide through the liver parenchyma without disrupting the parenchyma architecture. For example, the jaws may a length AA or 50, 60, 70 or 80 mm, and a width BB of 4, 5, 6 or 7 mm. The spring26helps to prevent accidentally closing down on the parenchyma to quickly which prevents parenchymal disruption. The jaws24may be straight or curved with a radius R of about 3-10 cm. Typically, the curvature of the jaws, if any, is in the downward direction, i.e., about an axis parallel to the axis of the hinge16.

The electrodes30may extend over the full length of each jaw24, or only partially over each jaw24, as shown inFIG. 1. The electrodes30may optionally be removable and separately replaceable.

A low cost embodiment of the tool may be provided by modifying a conventional hemostat clamp having long slender jaws, to include the spring26, the electrodes30and connectors22.

As used for hepatic resection, the surgeon slides the jaws24through the liver parenchyma. With the jaws appropriately positioned around a vessel or biliary radical, the jaws24are slowly closed via the surgeon squeezing the finger rings18towards each other. The electrodes30on the inside of the jaws are clamped or pressed onto opposite sides of the vessel. The spring26acts against this closing movement, helping to provide a slow and controlled movement. With the tool10held momentarily in a fixed position, RF energy is then provided to the electrodes30, sealing the vessel.

The tool may of course also be used for other surgical procedures on other organs apart from the liver.

From 2010-2012, a total of 51 patients underwent >30% liver resection for malignant disease. All patients underwent open laparotomy for hepatic resection. The patient sample was diverse. The majority of patients underwent resection for metastatic disease to the liver; 4 gallbladder cancer with radical liver resection; 1 hepatocellular carcinoma; 3 patients had documented cirrhosis. Procedures included: 7 patients were combined colorectal primary and liver resection; 2 patients underwent second resection for recurrence; 7 patients had additional nanoknife procedures at the time of resection. Post-op adverse events within 30 days of surgery included 0 bile leaks; 1 blood transfusion; 1 return to operating room for colon anastomatic leak; no intra-abdominal abscess. Use of the present tool as described appears to be a safe and effective technique for major hepatic resection with minimal post-operative adverse events.

During use of a bipolar surgical cautery tool, heat generated by the tool tends to result in char forming on the jaws. Char causes the jaws to stick to the tissue being cauterized, making the surgery more difficult. Char also increases the electrical resistance between the jaws, reducing the cautery effect of the tool. Char can be reduced by supplying an irrigation fluid to the cautery site, reducing the need for frequently stopping the procedure to clean char from the jaws.

As shown inFIG. 2, a bipolar surgical cautery tool50may be similar to the tool10shown inFIG. 1and further include irrigation to reduce char. Irrigation may be provided via an irrigation port or fitting52adapted for connection to a source of irrigation fluid, such as saline. The irrigation port52is connected to an irrigation line54on or in the tool leading to the electrode56. The irrigation line54may simply have a single outlet at the electrode56, or it may have multiple outlets58spaced apart along the electrode. The irrigation line54may be provided as a flexible tube attached to the tool50. Alternatively the irrigation line54may be provided as an internal duct leading from the arm12to the electrode56.

As shown inFIG. 4, in another design, one or both arms12may optionally be covered or coated with an insulating material66, such as plastic or rubber, with the irrigation line54formed in insulating material66. The insulating material may also optionally cover one or both finger rings18. As shown inFIG. 5, if the insulating material66is used, the irrigation line54may alternatively be provided as an open flow space between the arm12and the insulating material66.

In use, the source of irrigation fluid connected to the irrigation port52may be linked to the RF generator switch so that irrigation fluid flows onto or out of the electrode56whenever the switch is on. By applying a constant drip or flow of irrigation liquid during cautery, char build up is reduced.

FIG. 3shows a modification of the jaw24where a projection62is provided on the electrode30on the upper jaw and a complementary groove60is provided on the electrode30on the lower jaw. The projection may extend parallel to the longitudinal axis of the arm24and typically has a height of 1-3 mm. Consequently, as the upper and lower jaws are brought together, while the electrodes are cauterizing tissue, they also form a pre-grooved line in the tissue for transection, after the seal has been completed.

Turning toFIG. 6, a tool70may be provided with the same design as the tool50shown inFIG. 2, further including suction for helping to remove excess blood and/or irrigation fluid. The tool70includes a port or fitting72for attachment to a suction source. One or more suction inlets74may be provided on one or both electrodes30or58, with the suction inlets74connected to a suction line76connecting to the suction port72. The suction line76may be designed in the same ways as the irrigation line54described above.

Referring toFIGS. 7 and 8, a microwave coaptive vessel sealing tool80has long tissue and vessel sealing jaws82. An alternate energy form i. e., microwave energy may be applied to the jaws from the microwave generator90, rather than using radio frequency energy, direct current, ultrasound, or other form of energy. Each jaw82, or an electrode on each jaw, is connected to a surgical microwave generator, e. g., of the type currently used for ablative therapies. The microwave coaptive vessel sealing tool80is designed for sustained uniform compression without shearing through the tissue. Gradual pressure may be applied along the jaws resulting in a very good seal of the tissue.

The microwave coaptive vessel sealing tool80may be designed to work like an ordinary hemostat. The closure may be a gradual compression process, protected by a spring or flexure resistance element84loaded mechanism to prevent tearing of larger blood vessels. The spring84may be mounted on or at the pivot connection86attaching the jaws to each other. The jaws may be extremely thin (as thin as the existing needles), for example 1, 2 or 3 mm wide, to allow for sliding it in to the liver parenchyma without tearing any of the vessels or tissues. The tools described above with reference toFIGS. 1-6may also optionally be connected to a microwave generator90instead of an RF energy source.

The tool80may be provided with an insulated covering with an optional inbuilt irrigation channel. If used, the irrigation channel may provide a steady drip of saline when the microwave switch is activated, to help to prevent the tissue from getting charred and keeping the jaws of the tool80clean. Using the tool may leave a pre-grooved line for transection after the seal has been completed. The tool may be capable of reducing parenchymal transection times in excess of 50%. With 55 mm of sealing length, the tool80may seal more tissue in one bite than existing devices, while still being versatile enough to seal small lengths of tissue. The tool80may be inexpensive to allow it to be used with existing microwave generators.

Thus, novel designs and methods have been shown and described. Various changes and substitutions may of course be made without departing from the spirit and scope of the invention. The invention, therefore, should not be limited, except by the following claims and their equivalents.