Abstract:
A disposable laparoscopic smoke evacuation system. The system utilizes a small fan unit and filter housed in a single disposable housing adapted to be connected between two laparoscopic surgical instrument assemblies via tubing and powered by batteries or available AC power.

Description:
FIELD OF THE INVENTION 
     The invention relates to surgical procedures and, more specifically, to a device and method for obtaining a smoke-free environment within the surgical field during laparoscopy. 
     BACKGROUND OF THE INVENTION 
     Laparoscopy is a fast growing surgical modality widely used in the treatment of certain prevalent physical ailments. Laparoscopy entails the introduction of an endoscope, light source and surgical instruments through ports formed in the patient&#39;s abdomen. In order to facilitate the procedure, the patient&#39;s abdominal cavity is inflated with a suitable gas to give the surgeon additional working area and minimize obstruction. Generally, laparoscopy avoids the risks of laparotomy, which requires the surgeon to open the abdomen and carry out the required procedure by his or her direct viewing. 
     The laparoscopic procedure is designed to avoid the surgical complications involved in a conventional laparotomy by allowing a surgeon to view the target site without opening up the patient&#39;s abdominal cavity. In a diagnostic laparoscopic procedure, only one channel is required through the patient&#39;s abdominal wall into the patient&#39;s abdominal cavity, into which the surgeon positions the laparoscope (laparoscopic camera) needed for viewing the underlying and overlying abdominal tissues and/or potential surgical field. 
     However, when the laparoscopic procedure requires tissue removal by ablation, several channels through the abdominal wall are required. These include a channel for the laparoscopic camera needed for viewing the surgical field, a channel for the laser or electrosurgical instrument used to burn the target tissue, a channel for insufflation (introduction of CO 2  gas into the patient&#39;s cavity to expand the patient&#39;s cavity) with CO 2  gas, and a means for withdrawal of gas and smoke. Note that insufflation with a suitable gas is required during the laparoscopic procedure so as to provide both increased cavity volume and optimal visual conditions during the surgical procedure. A smoke clearing system is usually employed in order to maintain both the visual clarity and proper abdominal pressure within the expanded cavity during the procedure. 
     A common procedure for positioning the laparoscopic assembly in the patient&#39;s abdominal cavity includes first making an incision into the patient&#39;s abdominal wall through which a large gauge needle is inserted. A suitable gas, typically CO 2 , is then introduced into the patient&#39;s abdominal cavity through the needle. The needle is then replaced with a trocar, which is then removed leaving behind a sleeve, or cannula, through which a laparoscope is introduced into the abdominal cavity. In order to perform laser or electrosurgery one or two additional small incisions are made in the abdominal wall over the surgical site and cannula/trocar assemblies positioned accordingly. These cannula/trocar assemblies may be used for the positioning of the insufflation tube as well as any other surgical instruments that may be required for the particular laparoscopic procedure. 
     A laparoscopic procedure typically requires a surgeon to employ either electrosurgery or laser surgery within the confined space of the patient&#39;s abdominal cavity. This surgery typically involves tissue burning or ablation. This tissue burning leads to the creation of smoke. Surgical smoke within the confines of a patient&#39;s abdominal cavity reduces the surgeon&#39;s view of the surgical site, increases the patient&#39;s hematocrit levels, and causes delays in the surgery while the smoke is cleared from the laparoscopic field. Efficient removal of the smoke is thus a necessity for the surgical team during the laparoscopic procedure. 
     One method for removing smoke from the laparoscopic field is described in U.S. Pat. No. 4,735,603. This patent describes an elaborate and complex system for re-circulating and cleansing the smoke-laden gas produced inside a patient&#39;s abdominal cavity during a laparoscopic procedure. The system consists of a CO 2  gas pump that pumps gas into the patient&#39;s abdominal cavity by way of a solenoid control valve and a filter of such pore size as to remove bacteria size debris. Gas and smoke within the cavity are then evacuated by a return line, through a smoke clearing filter, a solenoid control valve, and a fluid trap before returning to the pump. A separate control module monitors the system for pressure variations and allegedly adjusts the pressure accordingly. The overall target cavity pressure is between 16-20 mm of Hg relative to atmospheric pressure. If the pressure exceeds 25 mm Hg or falls below 10 mm Hg the central control module closes the solenoid valves, which isolates the patient from the continued actions of the pump and allows the pressure to adjust accordingly. This system is large, cumbersome and can be costly. 
     Other laparoscopic smoke removal systems include: (1) suction devices which permit some air to be removed from the patient&#39;s cavity but require an equal input of gas back into the patient; (2) removal of smoke by opening a stopcock on one of the trocars, thus allowing the insufflation gas, laden with smoke, to be carried directly into the operating room; or (3) use of an adapted probe which can be inserted into the trocar for direct removal of smoke from the surgical site. Generally, the present systems are bulky, non-disposable, of complex design, are costly, and relatively large in size. Some devices also require connections to a house vacuum system within the surgical room. As such, it is unlikely that hospitals or health care offices that do not engage in numerous laparoscopic procedures will be able to justify the purchase of a conventional smoke removal system. 
     There is thus a need for a cost-effective solution to the removal of surgical smoke during a laparoscopic procedure. 
     There is also a need for a disposable, pre-sterilized smoke evacuation system that can be economically obtained and utilized by hospitals that do not routinely engage in laparoscopic procedures. It is with the above-referenced problems in mind that the present invention was developed. 
     SUMMARY OF THE INVENTION 
     The present invention is a smoke evacuation system utilizing a disposable inline gas pump/fan and filter apparatus comprising a housing defining an interior chamber and an inlet port and an outlet port. There is preferably an inline fan unit positioned in the interior chamber and a filter positioned in the interior chamber. The fan unit is preferably positioned between the inlet port and the filter. The apparatus has a power supply operably connected to the fan unit wherein the fan unit draws smoke-laden air from the patient&#39;s body cavity through the inlet port, past the fan, and pushes air through the filter, and the cleansed air is passed through the outlet port. Thereafter the cleansed air is re-introduced into the patient&#39;s cavity. 
     The present invention is connected between two laparoscopic cannula/trocar assemblies and works to eliminate surgical smoke and vapor, which has been created by the laser or other surgical devices, from the patient&#39;s abdominal, or other expanded body cavity during a laparoscopic procedure. The present invention comprises a small, portable, and disposable smoke clearing device which houses at least a fan unit and a filter media. Attached on one end of the smoke clearing device is a first flexible hollow tube attached to one of the cannula/trocar assemblies. Attached on the opposite end of the smoke clearing device is a second flexible hollow tube attached to the other cannula/trocar assembly, or other surgical device, inserted into the patient&#39;s abdominal or other body cavity. 
     The smoke clearing device is operated during a laparoscopic procedure to draw smoke from the surgical site out of the abdominal cavity, through the filter media, and return filtered gas back into the abdominal cavity. The present invention can best be understood by reference to the drawings and the detailed description below, wherein like parts are designated with like numerals throughout. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic sectional view of a laparoscopic surgical site showing the input and evacuation cannula tubes, insufflation tube, electrosurgical instrument, and smoke clearing device in accordance with the present invention. 
     FIG. 2 is a perspective view of the smoke clearing device of the present invention. 
     FIG. 3 is a section taken along line  3 — 3 ′ of FIG. 2 of the components of the filter system in the smoke clearing device of the present invention. 
     FIG. 4 is a section showing an alternative embodiment of the present invention. 
     FIG. 5 is a cross-sectional view of a power supply for the present invention. 
     FIG. 6 is a section showing another alternative embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the present invention is embodied in a smoke clearing device,  10  which includes a rigid housing  12 , preferably defining three internal chambers (shown in later Figures). The housing  12  may be made out of a variety of materials, such as a metal or a plastic, as long as the material facilitates the device&#39;s use and is preferably disposable. The housing  12  preferably has a generally rectangular box shape or it may have a generally cylindrical hollow shape, preferably with rounded corners. The housing  12  contains an inlet port  14  at one end, i.e., on one side and an outlet port  16  at the other end, i.e., on the opposite side. One end of an inlet tube  18  is connected to the inlet port  14 . One end of an outlet tube  20  is connected to the outlet port  16 . This tubing is preferably conventional sterile flexible plastic tubing. It is envisioned that conventional Luer lock structures  22  will be used to connect the tubes  18  and  20  to the housing  12 , but other locking structures could alternatively be used. 
     The patient&#39;s inner cavity, such as the abdominal cavity, is shown as  24  and the patient&#39;s skin is schematically shown as  25  in FIG.  1 . The patient&#39;s tissue which is to be removed is shown as  26 , with the surgical smoke shown and indicated as  26   a ,  26   b  and  26   c . Three trocars containing laparoscopic surgical instrument clusters  28 ,  30  and  32  extend through the patient&#39;s skin  25  into the cavity  24 . 
     These groups of instruments are representative of the type of instruments that are typically used in laparoscopic surgery. Each instrument cluster includes a cannula/trocar for introducing the instrument into the patient&#39;s cavity and maintaining a seal to the cavity  24  to preclude gas escape from the cavity  24 . Each cannula/trocar has a single channel or passage along its length that allows instruments to be inserted into the body while maintaining the intra-abdominal pressure created by insufflation. Instrument cluster  28  is a single channel instrument cluster which serves to house the laser instrument  34  and direct the laser beam to the operating site. An annular channel  36  around the instrument  34  within the trocar serves as an annular egress passage from near the operating site for gas to be drawn around the laser instrument  34  and out of the patient&#39;s cavity to the smoke clearing device  10  of the present invention. 
     Instrument assembly  30  serves as a channel for the fiber optic laparoscopic camera and light  38  and also provides an annular inlet passage for the insufflation gas from an insufflator  40 . The insufflator  40  may be a compressed gas cylinder and regulator valve assembly or a pump which supplies an initial volume of CO 2  gas. The other instrument assembly  32  provides both a channel  42  for the return of filtered re-circulated gas from the smoke clearing device  10  and may also may include an additional surgical instrument  44  which may be used for manipulating, dissecting or ablating tissues. 
     The outlet tubing  20  is connected at one end to the outlet port  16  of the device  10 . The other end of the outlet tubing  20  is secured to the trocar/cannula of the instrument assembly  32  via a Luer lock assembly  22  to a valved port  46  on the trocar. Preferably a valved port  46  is provided with the Luer lock, although the valve portion may be omitted in some applications. The trocars have seals and flapper valves (not shown) within them to form a positive seal around the inserted instrument to maintain positive pressure within the body cavity  24  and preclude gas leakage from the cavity  24 . Regardless of the presence or absence of a valved port, the connection between the tubing  20  and the instrument assembly  32  is to be sealed to outside air sources. 
     Similarly, the inlet tubing  18  is connected at one end to the inlet port  14  of the device  10 . The other end of the inlet tubing  18  is secured to the trocar/cannula of the instrument assembly  28  via another Luer lock assembly  22  preferably to a valved port  46  on the trocar of the assembly  28 . Again, the trocar has seals and flapper valves (not shown) within it to form a positive seal around the inserted instrument to maintain positive pressure within the cavity  24  and preclude gas leakage from the cavity  24 . 
     During the laparoscopic procedure, gas from the patient&#39;s body cavity  24  is directed, as shown by the arrows, through the channel  36 , out the port  46  in the instrument assembly  28 , and through tubing  18  to the smoke clearing device  10 . The unfiltered gas will then enter the smoke clearing device  10 , be filtered, and will be returned to the patient&#39;s cavity  24  by way of the laparoscopic instrument assembly  32 . 
     The laparoscopic port valve  46  allows for the smoke clearing device  10  to maintain a continuous flow of smoke out of the patient&#39;s cavity  24 , or if preferred, to adjust the flow by simply manually conforming the valve so as to adjust the port diameter. Thus, it is within the scope of the present invention to be able to use the laparoscopic valve  46  on the instrument assembly  28  in a manner so as to control the suction pressure developed by the smoke clearing device  10 . Note that the valve  46  is preferably designed not to close all the way so as to avoid undue vacuum pressure being drawn within the suction tubing  18  and/or in the smoke clearing device  10 . Where a smaller level of suction is required the user has the ability to adjust the valve  46  so as to regulate the volume of gas being pulled toward the smoke clearing device. Alternatively, the valve  46  on the instrument assembly  32  may be throttled to adjust the flow rate through the device  10  back into the patient&#39;s abdominal cavity  24 . 
     The tubing  20  is connected to the outlet port  16  of the smoke clearing device  10  preferably using a Luer lock assembly  22 . The other end of the tubing  20  runs to the cannula/trocar of instrument assembly  32  where it is fitted into a valved port  46  via another Luer lock assembly  22 . Again, and throughout this specification, all references to Luer locks herein are exemplary only. Any suitable connection mechanism may be utilized. The valved port  46  on the instrument assembly  32  communicates with an annular channel  42  which directs the returning gas back into the patient&#39;s cavity  24 . 
     The insufflator  40  is connected to the trocar/cannula of instrument assembly  30  via tubing  48 . The tubing  48  connects to a port  46  in the two chamber instrument assembly  30  by another Luer lock assembly  22 . The cannula of the instrument assembly  30  extends through the patient&#39;s abdominal wall  25  into the cavity  24 . The first or central channel provides a path for the laparoscopic camera and light  38  utilized to view the surgical field. The annular channel  49  around the laparoscope  38  provides a path for the CO 2  gas from the insufflator  40  into the patient&#39;s cavity  24 . 
     As illustrated by arrows, the smoke clearing device  10  directs the flow of surgical smoke ( 26 A,  26 B and  26 C) created during a laparoscopic procedure from the target site  26 , through passage  36  in the laparoscopic assembly  28 , through the laparoscopic port  46 , into the tubing  18  and into the smoke clearing device  10 . After flowing through the filter in device  10  the gas is returned to the target site by passing through tubing  20  and down the channel  42  of the cannula of the instrument assembly  32  to the cavity  24 . Thus, the present embodiment is part of a closed system whereby the insufflation gas is filtered and re-circulated to maintain a constant level of gas in the patient&#39;s cavity  24 . 
     There are connections between the laparoscopic assembly port and tubing, between the tubing and the smoke clearing inlet port, between the smoke clearing outlet port and tubing, and between tubing and the one channel cannula port. Each connection is preferably accomplished using a Luer lock as above described, but other known connections are envisioned. Each connection is envisioned as being sealed, but easily detachable when appropriate. FIG. 1 shows one embodiment of a surgical set up using the present invention. However, the present invention is not limited to a particular set up, and can be used with more or fewer instruments and tubing, depending on the surgeon&#39;s needs and the particular laparoscopic task at hand. 
     Note that the tubing is provided in a sterile form so as to limit the likelihood of infection at the surgical site. Additionally, these tubes preferably have smooth interior surfaces thereby reducing friction between the surgical smoke and the tubing walls, and are designed to be able to resist collapse from the forces exerted by the fan suction. The tubes may be constructed out of any of the plastic or rubber compositions commonly used for similar medical supplies. 
     FIG. 2 is a top view of the smoke clearing device  10 . As indicated above, the device includes a rigid housing  12  defining an intermediate interior chamber  62  (shown in FIG.  3 ). A fan unit  54  is positioned within the intermediate interior chamber  64 , as is a filter  56  (all shown in FIG.  3 ). A power source  58  is shown in communication with device  10 . 
     FIG. 3 is a sectional view of one preferred embodiment of the smoke clearing device  10 . The inlet end wall of the device  10  has an inlet port  14  connected to tubing  18  by a Luer lock  22 . The smoke clearing device housing  12  preferably defines three chambers  62 ,  64 , and  66 , each of which is defined by the walls of the smoke clearing device housing  12  and by one of either the filter  56  or the fan mounting structure  68 . 
     The anterior chamber  62  is defined by the smoke clearing device housing  12  and the fan mounting structure  68  supporting the fan unit  54 . The anterior chamber  62  is continuous with the intermediate interior chamber  64 , which is defined by the housing  12  of the smoke clearing device  10  and, at one end, the fan mounting structure  68  supporting the fan unit  54 , and on the other end the filter  56 . There is also an exhaust chamber  66  defined by the smoke clearing device housing  12  and one face of the filter  56 . The interior wall surfaces of the smoke clearing device housing  12  are preferably smooth so as to reduce friction on the flow of gas. Gas flow, delivered by the action of the fan unit  54 , enters the smoke clearing device  10  through the inlet port  14 , travels through the anterior chamber  62  through the fan mounting structure  68 , through the fan unit  54 , to the intermediate interior chamber  64 , through the filter  56 , and out of the device  10  by way of the outlet port  16  in the end wall of the exhaust chamber  66 . 
     The inline fan unit  54  is preferably positioned directly in the flow path of gas through the smoke clearing device  10 . This direct, in-flow-path positioning provides for the maximum creation of vacuum pressure for sucking the surgical smoke from the patient&#39;s cavity  24  and advancing it through the smoke clearing filter  56 . The fan blades  55  are driven by a fan motor  57  which is contained within a fan motor housing. The fan unit  54  is attached to the smoke filter device by way of a fan mounting structure  68 . The fan mounting structure  68  is a narrow web support which is positioned in a plane normal to the base and longitudinal axis of the smoke filtering device  10  and spans the interior of the device so that the fan unit is stabilized through attachments to both the top and bottom of the device and/or its sides. The fan mounting structure  68  must have open space for the smoke to pass through. The fan mounting structure  68  preferably has a skeletal configuration so as to minimize restriction to gas flow such as a criss-cross or X-configuration of legs extending between the top and bottom of the smoke clearing device housing  12  or simply a series of three or more support legs extending transversely from the fan motor body to the outer walls of the housing  12 . 
     It will be appreciated that the exact position of the fan unit  54  within the smoke clearing device  10  may be embodied in a number of configurations. For example, the fan unit can be positioned adjacent to the inlet port  14  in chamber  62  of the smoke clearing device  10 , or it can be adjacent the filter  56 , as is shown in FIG.  3 . The fan unit  54  also may be positioned after or downstream of the filter  56 , rather than before the filter  56  or it may also be positioned between the two filters as illustrated in FIG.  6 . Additionally, the fan unit  54  may have any number of fan blades as long as the fan unit  54  is still of an effective capability to efficiently remove the surgical smoke generated during a procedure. 
     The fan unit  54  may be adjustable in speed. This would give the surgical personnel the ability to adjust the amount of suction applied to the laparoscopic field in a manner other than closing the laparoscopic port valve  46  as described above. Thus, dependent upon the amount of anticipated smoke or the volume of gas needed to be filtered, the appropriate fan speed could be selected. 
     The fan speed also may be adjusted depending on the type of filter which needs to be used. For example, if a filter with very small pores is used, the differential pressure generated across the filter will be higher and the fan speed may need to be increased accordingly. Alternatively, if a large pore size is used, the speed could be reduced. Finally, as the filter becomes clogged with contaminants the speed could be increased. 
     The surgical smoke is drawn through the inlet port  14  of the smoke clearing device  10  and into the anterior chamber  62  by the suction created by the fan unit  54 . The fan unit  54  pulls the smoke through the blades  55  and pushes it into the intermediate interior chamber  64 . Once on the front or downstream side of the fan unit  54 , the smoke laden air is forced through the filter  56 , into the exhaust chamber  66 , and finally out of the smoke clearing device by way of outlet port  16 . 
     FIG. 3 illustrates one embodiment of the filter system of the present invention. Smoke-laden gas is directed through a filter  56  located in the posterior chamber portion of the smoke clearing device  10 . Preferably the filter  56  has a filtration capacity ranging from HEPA to ULPA specifications and is commercially available from a supplier such as Buffalo Filters, Buffalo, N.Y. The filter  56  is preferably held in place in the smoke clearing device  10  by a pair of spaced peripheral ribs  70  and  72  which project inward from the exterior walls of the smoke clearing device&#39;s housing  12 . It is envisioned that the filter  56  is sealed to the inner edges of the ribs  70  and  72  in the smoke clearing device housing  12  so that no unfiltered air is allowed to pass through the device  10  without first being cleansed. Additionally, the filter  56  may come in a variety of widths and dimensions as long as the desired level of air cleansing is accomplished. 
     A filter access door  74  may optionally be provided in one of the side walls  80  of the housing  12 . The filter access door  74  permits changing of the filter  56  as the differential pressure builds up across the filter due to buildup of contaminants. This door  74  preferably has a handle  76  of conventional design and may be hinged at hinge  78 . The door  74  is preferably sealed by a suitable gasket material (not shown) to prevent gas leakage or air entry into the system during use. As is shown in FIGS. 2 and 3, the door  74  permits the filter  56  to be slid out of the housing  12  and easily replaced. 
     An alternative embodiment of the filtering system illustrated in FIG. 3 is shown in FIG. 4, and includes a pre-filter  82  positioned before the primary filter  56 . It is envisioned that the pre-filter  82  will have the exact same dimensions and orientation as does the primary filter  56 . The pre-filter  82  has a larger diameter filter pore and is hydrophilic in nature. The pre-filter  82  would remove the larger smoke particles, particulates, and water vapor. The pre-filter  82  reduces the prevalence of filter clogging particulates in the primary filter  56 . Once the surgical smoke has passed through the pre-filter  82 , it enters the primary filter  56 , which removes any remaining particulate debris from the air flow. Other embodiments are envisioned which may include adding additional filters in various configurations. Thus, there could be a single filter or a plurality of filters, depending upon the particular application. In addition, the fan unit  54  may be reverse driven to pull gas through the filter  56  in a direction opposite the arrows shown in FIGS. 3 and 4. In this instance, the tubing  18  and  20  would simply be connected in reverse, i.e., swapped between inlet port  14  and outlet port  16  so that the surgical smoke passes first through the filter or filters before reaching the fan unit. 
     The power source  58  is preferably contained in a separate compartment  84  attached to the outside of the smoke clearing device housing  12 . As shown in FIG. 5, the power source  58  preferably comprises a set of DC batteries  86  connected in series or parallel. A rocker, push button, or slide power switch  88  is positioned on the power source compartment  84  so that the user can electrically turn the device  10  on and off when appropriate. The smoke clearing device  10  is preferably turned “on” by depression of the switch and turned “off” by a second depression of the same switch. Alternatively, the switch can also be of a sliding configuration incorporating a variable power function that varies power to the fan to permit adjustment of fan speed and thus suction, flow rate, and gas throughput. 
     It can be appreciated that the power source  58  may also be comprised of two or more rechargeable DC or other type of batteries connected in series or in parallel. In this embodiment, a standard charging base, which contains a cord and plug to receive energy from a standard hospital wall electric outlet, would also be appropriate. Any other suitable power source which could power the device  10  may also be used. 
     The smoke clearing device  10  is self contained. Thus, the present invention eliminates any need for connection to a hospital vacuum system, or for that matter, a hospital power supply. As such, the device  10  may be used at health care facilities which do not contain in-house vacuum systems. Additionally, the device is advantageous in settings which do contain house vacuum systems where it is preferred that the in-house vacuum not be exposed to the surgical material introduced through the laparoscopic procedure. 
     The device  10  may also be configured with a clip device on the housing  12  and/or on the tubing  18  and  20  for securing the device  10  and tubing to the surgical drapes over the patient&#39;s body. Thus, from the foregoing description it can be appreciated that the present invention provides a sterile, portable, convenient, and relatively inexpensive alternative to those relatively cumbersome smoke evacuation systems of the prior art. It is also envisioned that the entire smoke clearing device could be packaged sterilely and sold in a sterile surgical kit form, which includes the housing with fan unit and filter(s) installed, tubing, and Luer locks (or other suitable tubing fasteners) in a sterile package. The power supply, in the kit form, could also include batteries in a separate package for installation and/or replacement during surgery as may be required. 
     Another alternative embodiment of the filtering system of the present invention, similar to the embodiment shown in FIG. 4 in many respects, is illustrated in FIG. 6 in which fan unit  54  is positioned between pre-filter  82  and primary filter  56 . 
     The present invention is not intended to be limited to the particular embodiments illustrated but is intended to cover all such alternatives, modifications, and equivalents as may be included within the spirit and broad scope of the invention as defined by the following claims. All patents, patent applications, and printed publications referred to herein are hereby incorporated by reference in their entirety. The scope of the present invention is defined by the following claims.