Abstract:
A headless, flexible, two-part, semi-flexible trocar is formed from two semi-circular sections to form a hollow tubular body having a flared proximal end and a tapered distal end. The sections may temporarily move with respect to one another to increase the diameter of the tubular structure. A top portion protruding beyond the body may readily be trimmed as desired to allow a greater range of motion for an optical or surgical instrument within the body cavity. A valve/fulcrum within the tubular structure helps control the optical or surgical instruments. When tissue needs to be removed from the body cavity, the stem of the trocar may be expanded to allow passage of the tissue being removed, which stretches the incision. The insufflation gas is injected into the body cavity at a point other than through the trocar, which further optimizes intraoperative optics while minimizing tissue trauma.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    (NOT APPLICABLE) 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    (NOT APPLICABLE) 
       BACKGROUND OF THE INVENTION 
       [0003]    The invention pertains to trocars and, more particularly, to flexible, low to no profile, two-piece, expandable trocars facilitating single incision laparoscopic surgery (SILS) allowing both instrument insertion/egress and having access for achieving pneumoperitoneum. 
         [0004]    Laparoscopic surgical techniques are both well known and widely practiced for performing a wide variety of surgical procedures. The major advantage of laparoscopic procedures is that no large incision needs to be made into a patient, thereby greatly reducing patient recovery time and typically, post-operative pain. In some cases, simple procedures performed laparoscopically may be done either on an outpatient basis, or with a limited hospitalization. SILS limits these smaller incisions to a single incision at the umbilicus. SILS is further pushing what typically has been an inpatient procedure to be completed as an outpatient basis. Such procedures previously typically required a multi-day hospitalization when conventional surgical techniques were used. 
         [0005]    Laparoscopic surgery typically utilizes multiple trocars through multiple small incisions for the insertion of a camera and surgical instruments, as well as introduction of materials such as sutures, repair meshes, and the like required for the specific surgical procedures. One or more additional trocars may be used to inflate the abdomen or other body cavity to facilitate the surgery being performed. The camera provides an image on a monitor which is used by the surgeon to guide his or her manipulation of the instruments. 
         [0006]    It has been observed that patient discomfort is proportional to the diameter of the trocars utilized for the surgery, large diameter trocars resulting in more discomfort, and small diameter trocars resulting in less discomfort. It has also been recognized that a puncture or incision made by a small diameter, for example, a 5 mm trocar may be virtually self healing, requiring no suture to close the puncture or incision (i.e., fascial defect) upon withdrawal of the trocar. This provides additional incentive to utilize small diameter trocars whenever possible. 
         [0007]    Conventional trocars utilized for laparoscopic procedures are typically substantially rigid and include a head disposed at the proximal end of a stem or shaft. A port and sometimes a valve are included to allow insufflation of the abdomen (i.e., the inflation with carbon dioxide or a similar gas). Insufflation of the abdomen during laparoscopic surgery creates a working space for visualization and performing surgery. While the abdominal cavity has been chosen to illustrate the use of the novel trocar of the invention, it will be noted that the novel trocar may be used in other body cavities as well. 
         [0008]    An opening in the trocar head allows the insertion of an optical device (e.g., a camera), surgical tools, or materials. However, the rigid head and the fixed diameter of conventional trocars present several problems. In particular, in SILS, the necessity of placing two 5 mm large-headed trocars in close proximity inserted through a single incision severely restricts movements of instruments inserted therethrough and interferes with successful completion of surgical procedures. A single millimeter difference in range of motion at the umbilicus translates to centimeters in range of motion at the operative site based on fulcrum mechanics. One problem is that rigid adjacent large-headed trocars contact one another, thereby limiting range of motion and severely restricting surgical instrument movement. 
         [0009]    In addition, the introduction of gas at the primary port (i.e., one of the adjacent trocars of the prior art) may interfere with clear laparoscopic imaging necessary for safety. 
         [0010]    It would, therefore, be desirable to provide a trocar that would provide improved access to a body cavity for performance of laparoscopic surgery and would move the gas insertion point away from the incision and working area. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    In an exemplary embodiment, a flexible expandable trocar includes a pair of semicircular pieces fitted one into another to obtain a required range of diameters. No head is provided. Rather, a flared end facilitates insertion of surgical instruments and/or optical elements into the body cavity. A top portion protruding from the body may readily be trimmed substantially flush with the patient&#39;s skin to allow the surgeon even greater range of motion for the surgical instruments. When tissue needs to be removed from the body cavity, the stem of the trocar may be temporarily expanded to allow passage of the tissue being removed. The expandability of the novel trocar design also allows the insertion of surgical instruments larger than the 5 mm instruments typically used. This provides the surgeon access to all available laparoscopic instrumentation to safely and efficiently complete the intended laparoscopic intervention (i.e., 10 mm graspers, laparoscopic staplers, specimen retrieval pouches). This temporary expansion may stretch the incision minimizing the requisite larger incision of the larger diameter trocar of the prior art. The insufflation gas may be injected into the body cavity at a different point than through the trocar. This is done using a device similar in construction to an “angiocath.” The size of the opening in the body wall left by this device is so small that no stitches are required at the completion of the surgery. No suturing translates to less wound complications, less cost, and greater intraoperative efficiency. At these puncture sites, patients rarely even realize that an additional body intrusion has taken place, and no post operative pain has been reported. Further, the performance of optical instruments benefits from moving the insufflation gas port away from the trocar as fogging and other effects caused by inserting insufflation gas at the trocar are eliminated. 
         [0012]    It is therefore an object of the invention to provide a trocar that allows a greater range of movement for surgical instruments and/or optical elements. 
         [0013]    It is another object of the invention to provide a headless trocar that allows insufflation gas to be inserted away from the trocar. 
         [0014]    It is still another object of the invention to provide a trocar formed from two semicircular pieces that fit one within the other. 
         [0015]    It is an additional object of the invention to provide a trocar whose stem may temporarily be diametrically expanded to facilitate removal of tissue from a surgical site and insertion and removal of large diameter instruments that may not require an enlargement of the incision. 
         [0016]    It is a further object of the invention to provide an improved trocar having a fulcrum within its stem and away from the head to improve manipulability of surgical instruments, optimizing the fulcrum advantage of single incision surgery. 
         [0017]    It is a still further object of the invention to provide an improved trocar using a tiny insufflation port inserted into a patient away from the trocar. 
         [0018]    It is still further object of invention that a slotted temporary cannula conducts the insufflation catheter through the abdominal wall allowing its removal while leaving the insufflation catheter in place. 
         [0019]    It is an object of invention that the bivalve or quad valve mechanism of the trocar is of a sponge nature to cleanse the optical lens and to apply an anti-fog liquid to the lens. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0021]      FIG. 1  is a side elevational, schematic view of a trocar and obturator of the prior art; 
           [0022]      FIG. 2   a  is a perspective view showing two semicircular pieces poised one above the other in a position to be formed into a trocar stem in accordance with the invention; 
           [0023]      FIG. 2   b  is an end elevational, schematic view of the semicircular pieces of  FIG. 2   a;    
           [0024]      FIG. 2   c  is an end elevational, schematic view of the two semicircular pieces of  FIG. 2   a  formed into an expandable circular structure; 
           [0025]      FIG. 3   a  is a side elevational view of a trocar in accordance with the invention formed from two semicircular pieces; 
           [0026]      FIG. 3   b  is an end elevational view of the trocar of  FIG. 3   a;    
           [0027]      FIG. 3   c  is a perspective schematic view of the two halves of the trocar of  FIG. 3   a  showing a flared end thereof and prior to assembly; 
           [0028]      FIG. 3   c ′ is a perspective schematic view of the two halves of the trocar of  FIG. 3   c  assembled into a complete trocar; 
           [0029]      FIG. 3   d  is a side elevational, schematic view of ribs of the trocar of  FIG. 3   a  disposed in a spiral configuration; 
           [0030]      FIGS. 3   e  and  3   f  are top plan, schematic views of two embodiments of a valve/fulcrum of the trocar of  FIG. 3   a;    
           [0031]      FIGS. 3   g  and  3   h  are side elevational, schematic views of two additional alternate embodiments of a valve/fulcrum of the trocar of  FIG. 3   a;    
           [0032]      FIG. 4  is a side elevational view of the trocar of  FIG. 3   a  with an obturator inserted therein; 
           [0033]      FIG. 5   a  is a simplified schematic system diagram of an arrangement suitable for injecting insufflation gas into a body cavity away from the trocar of  FIG. 3   a;    
           [0034]      FIGS. 5   b  and  5   c  show alternate embodiments of an inserter that may be split along its major axis for removal from a catheter; and 
           [0035]      FIG. 6  is a schematic plan view of an abdominal region of a patient with a pair of trocars inserted through the umbilicus and with a remotely located gas insertion port. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    The disadvantages of one-piece, rigid, headed trocars of the prior art have been discussed hereinabove. The trocar of the invention overcomes all of the disadvantages presented by such prior art trocars. The novel trocar is formed from two semicircular sections that mate to form a trocar whose diameter is temporarily expandable as the two semicircular sections move with respect to one another. 
         [0037]    Further, the elimination of the trocar head allows a greater range of movement for surgical instruments and/or optical elements, thereby allowing access to a larger surgical field. An excess length of the trocar extending outside a patient&#39;s body may, when desired, readily be trimmed to allow even more range of motion for surgical instruments. 
         [0038]    The elimination of the trocar head with its gas port yields the advantage that the insufflation gas may be injected into the body cavity of interest remotely from the site of the trocar. This eliminates the problem of fogging of optical elements caused when insufflation gas is injected through the stern of the trocar as is done in trocars of the prior art. 
         [0039]    Referring first to  FIG. 1 , there is shown a side elevational view of a trocar of the prior art, generally at reference number  100 . Trocar  100  has a head  102  coaxially attached to a hollow stem  104  having a distal tip  106 . A series of ridges  108  are disposed on an outer circumference of hollow stem  104 . A gas injection port  110  forms a part of the head  102 . An obturator having a tip  112   a,  a handle  112   b,  and a shaft  112   c  is shown inserted in trocar  100 . A central opening  114  in head  102  allows access to the hollow interior, not specifically identified, in stem  104 . 
         [0040]      FIG. 2   a  shows a perspective view with two semicircular sections  204   a,    204   b  poised one above the other in a position to be formed into a trocar stem in accordance with the invention, generally at reference number  202 . An upper semicircular section  204   a  is poised above a lower semicircular section  204   b , semicircular section  204   b  being inverted with respect to semicircular section  204   a . Arrows  212  indicate the direction of movement of semicircular sections  204   a ,  204   b  toward each other. When engaged, major outside surface  206  of semicircular section  204   a  contacts major interior surface  208  of semicircular section  204   b.  The sections  204   a,    204   b  are generally formed of a thin polymeric material, although other materials may be suitable, and the invention is not meant to be limited to a particular material, which is flexible and resilient to provide for slight expansion while enabling retraction to their original shapes. 
         [0041]      FIGS. 2   b  and  2   c  show end elevational, schematic views of the semicircular pieces  204   a,    204   b  of  FIG. 2   a  poised one above the other, and engaged with one another, respectively. In addition to arrows  212  indicating the direction of vertical motion, arrows  214  indicate the direction of horizontal motion (i.e., the squeezing compression of one of semicircular sections  204   a,    204   b ). 
         [0042]    As seen in  FIG. 2   c , semicircular section  204   a  has been compressed and inserted into semicircular section  204   b  such that major outer surface  206  engages major inner surface  208 . As semicircular pieces  204   a,    204   b  are made from a resilient material and both have relatively thin cross sections, material memory of the compressed semicircular section  204   a  creates an outward pressure against major inside surface  208 . The surfaces  206 ,  208  may circumferentially slide against each other when pressure is exerted on major inside surface  208  and an inside surface of semicircular section  204 . Such pressure may be exerted from inside the stem of a trocar  200  ( FIG. 3   a ) when tissue must be withdrawn from within a body cavity or when a larger tool such as a stapler or the like is inserted through the trocar  200 . That is, when assembled, the trocar stem may be sized to accommodate a 5 mm tool or camera or the like. There are times during a surgical procedure when a larger tool must be inserted through the trocar or when tissue or the like must be extracted, and rather than inserting a larger diameter trocar, the expandable trocar of the invention is capable of accommodating the larger object, for example a stapler having a diameter of 10 mm. As the object is inserted into the trocar, the semicircular pieces  204   a,    204   b  separated slightly to expand the inside diameter of the trocar, while maintaining the insufflated gas defining the surgical working space. When the object is removed, the resilient nature of the semicircular pieces  204   a,    204   b  causes the pieces to contract on themselves and return to the original diameter. In an abdominal procedure especially, the abdominal wall is resilient and capable of slight expansion so that a wider incision will not be necessary. In the event that the semicircular pieces  204   a,    204   b  are inadvertently separated, the abdominal wall or the like will contain the pieces so that the procedure can be finished and the trocar(s) can be safely removed. The larger diameter extractions and insertion of larger diameter tools such as a 10 mm staple typically occur at the very end of surgery, and separation of the semicircular pieces  204   a,    204   b  would be of no consequence. 
         [0043]      FIG. 3   a  shows a side elevational, schematic view of the trocar including a flared proximal end  216  and a narrowed tip  218 .  FIGS. 3   c  and  3   c ′ show a perspective schematic view of two halves  204   a,    204   b  of trocar  200  of  FIG. 3   a  prior to assembly. The two trocar halves  204   a,    204   b  are joined by moving the two halves  204   a,    204   b  together as shown by arrow  254 .  FIG. 3   c ′ shows trocar  200  after halves  204   a,    204   b  are assembled.  FIGS. 3   c  and  3   c ′ show more detailed views of flared proximal end  216  of trocar  200 . The flared design is important to assist the surgeon with “threading” a long 5 mm instrument to and through a small orifice. 
         [0044]    A series of ribs  215  are disposed circumferentially around the outside surface of the stem formed from semicircular sections  204   a,    204   b.  Ribs  215  may be disposed either parallel to one another or at an acute angle compared to an axis perpendicular axis to the major axis of trocar  200  to one another. In other embodiments, ribs  215  may be continuous spirals.  FIG. 3   d  is a side elevational, schematic view of ribs  215  disposed in a spiral pattern along a portion of trocar  200 . The ribs  215  generally serve to secure the trocar in place during the procedure by engaging the abdominal wall or the like. With the spiral pattern, the trocar may be rotated to adjust its position in the patient. 
         [0045]    A demarcation line  228  shows the break between semicircular sections  204   a,    204   b.  A line  220  shows one possible location of an edge of semicircular section  204   b  inserted into semicircular section  204   a.    
         [0046]    A valve/fulcrum  210  is disposed within a hollow region, not specifically identified, of the stem of trocar  200  perpendicular to the major axis thereof. Valve/fulcrum  210  is typically formed from a thin, resilient, impermeable material and is typically disposed approximately between flared proximal end  216  and tip  218  of the trocar  200 . It will be recognized that valve/fulcrum  210  may be placed elsewhere along the major axis of trocar  200  to meet a particular operating requirement. 
         [0047]    Valve/fulcrum  210  serves two major purposes. First, valve/fulcrum  210  serves as at least a partial seal to minimize outflow of the insufflation gas from the body cavity into which trocar  200  is inserted. That is, the valve extends across the interior channel in the trocar to prevent gas outflow. Its second function is to provide a fulcrum that assists a surgeon in controlling surgical instruments inserted through trocar  200  into the body cavity. 
         [0048]    Valve/fulcrum  210  may be implemented in several manners. In a first embodiment (see  FIG. 3   e ), a thin flap is formed in two sections, a first of which is attached to an inside surface  208  of semicircular piece  204   b,  a second of which is attached to an analogous inside surface (not specifically identified) of semicircular piece  204   a.  Line  250  shows the split between two sections of valve/fulcrum  210 . 
         [0049]    One important design consideration for valve/fulcrum  210  is that it not “slime” the tip of an optical element inserted into the body cavity. Such “sliming” regularly occurs by current trocar designs when residue builds up on valve/fulcrum  210  from surgical instruments being withdrawn from the body cavity therethrough stalling and interrupting surgical progress. Safe laparoscopic surgery is predicated on the quality of visualization, the same as driving a car. One solution (see  FIG. 3   g ) to the “sliming” problem may include using a two-layer structure for valve/fulcrum  210  wherein a fabric layer  266  is added to the thin, resilient, impermeable layer  264  whose sole function is to wipe the end of an optical instrument as it passes inwardly (i.e., toward the body cavity). Yet another novel solution to the “sliming” problem is to form valve/fulcrum  210  from a sponge or sponge-like material  268  (see  FIG. 3   h ). The sponge material  268  may be treated either at the time of manufacture or at the time of use with an anti-fog or other chemical treatment to help improve the functioning of any optical element inserted into a body cavity through trocar  200 . In an alternate embodiment (see  FIG. 3   f ), an additional split  252  is added to the first split  250 . 
         [0050]    The diameters of various sections of trocar  200  may be seen in  FIG. 3   a . The diameter of tip  218  is shown at reference number  224 , the diameter of the sleeve at reference number  222 , the outside diameter of ribs  215  at reference number  226 , and the diameter of flared proximal end  216  at reference number  230 . The relationship of these diameters may readily be seen in  FIG. 3   b . It will also be noted in  FIG. 3   b  that ribs  215  may not extend over the entire surface of semicircular section  204   a,    204   b.  Rather, edge portions of semicircular sections  204   a,    204   b  may be devoid of ribs  215  to facilitate the mating of the two semicircular sections  204   a  and  204   b.  Generally, the ribs  215  assist in securing the trocar within the body wall. 
         [0051]      FIG. 4  shows a side elevational, schematic view of the trocar  200  of  FIG. 3   a  with an obturator inserted therein. The obturator has a handle  232 , a tip  234 , and a shaft  236 . Handle  232  has a recess  238  formed therein, sized and configured to accept an outer edge of flared proximal end  216  of trocar  200  therewithin. By capturing the outer edges of flared proximal end  216 , more stability is provided to trocar  200 , especially as it is inserted into a body cavity. Conventional practice is to insert trocars into body cavities with obturators in place as shown in  FIG. 4 . 
         [0052]      FIG. 5   a  shows a simplified schematic system diagram of an arrangement suitable for injecting insufflation gas into a body cavity remotely from trocar  200 , generally at reference number  300 . Apparatus  300  is similar to an angiocath believed to be well known to persons of skill in the medical arts. A thin, biluminal catheter  302  having a balloon  304  proximate its distal end  306  is adapted for insertion through the wall of a body cavity  308 , for example, the abdominal cavity of a patient, typically using an inserter  310 . Balloon  304  is selectively inflated and deflated by an inflation syringe  312  in combination with a valve mechanism  314  through a tube  316  connected to a first lumen (not shown) of biluminal catheter  302  at a junction  318 . A gas port  320  is connected to a second lumen (not shown) of biluminal catheter  302  at junction  318  by a tube  322 . It is desirable to minimize the length of the tube  322  to minimize flow resistance. 
         [0053]    Once inserted into the body cavity in which laparoscopic surgery is to be performed, balloon  304  of biluminal catheter  302  may be inflated, and slotted inserter  310  may be withdrawn. Once balloon  304  is inflated, biluminal catheter  302  may be drawn back until inflated balloon  304  seals against the inner surface  324  of the body cavity wall  308 . This forms a relatively vapor tight seal. The puncture through body cavity wall  308  through which biluminal catheter  302  was inserted closes around an outer surface of the biluminal catheter  302 . Once this seal is formed, insufflation gas, typically CO 2  may be injected into the body cavity from gas port  320  via a second lumen of the biluminal catheter  302 . 
         [0054]    Referring to  FIGS. 5   b  and  5   c , the slotted insertion  310  is of no further use during the laparoscopic surgery once biluminal catheter  302  is inserted through body cavity wall. Consequently, it would be desirable to get inserter  310  out of the way. To accomplish this, inserter  310  may be formed with a slit  326  along a major axis thereof that allows biluminal catheter  302  to separate inserter  310  along slit  326  by exerting pressure on thinned region  332  from within inserter  310  allowing inserter  310  to readily be removed from biluminal catheter  302 . 
         [0055]    In  FIG. 5   c , an alternate embodiment of a mechanism for separating inserter  310  along a major axis thereof is shown. A tab  328  may be attached to a filament  330  embedded in thinned region  332  of inserter  310 . Filament  330  is shown vertically offset from thinned region  332  for clarification. In practice, filament  330  is preferably coincident with a center of thinned region  332 . It will be recognized that a thinned region  332  may be sufficient to remove inserter  310  without need of pull tab  328  and filament  330 . 
         [0056]      FIG. 6  is a schematic representation of a portion of a human abdomen, generally at reference number  350 . A pair of trocars  200   a,    200   b  is shown inserted into an abdominal cavity, preferably through a single incision in the umbilicus. A gas injection point  252  is shown displaced from umbilicus  250 . 
         [0057]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.