SURGICAL INSTRUMENT FOR PROVIDING
SUCTION AND IRRIGATION
This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/116,537 filed Jan. 19,1999, fully incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to surgical instruments and in particular, to an electrosurgical laparoscopic instrument that provides suction and irrigation.
Surgical instruments are available that provide irrigation fluid and suction force to irrigate and evacuate the tissue at a surgical site or area where a surgical procedure is being performed. One example of such an instrument is an electrosurgical laparoscopic instrument 10, FIG. 1, which com- 20 prises a housing enclosure (or cannula) 12 having a distal end 16 and an electrode 18 extending from the distal end 16. The housing 12 forms a lumen or passageway 19 and is typically constructed of stainless steel with a Teflon shrink wrap insulation. The electrode 18 includes an insulated electrode connector 20 that extends into the stainless steel tube housing 12 and is attached to a portion of the inner surface 22 of the housing 12. In use, the laparoscopic instrument 10 is passed through a trocar. ^
According to one application of this instrument 10, the tip of the electrode 18 is used to dissect a gallbladder from the liver. Energy is applied through the surgical instrument 10 to the electrode 18 to assist in coagulation and cauterization during this dissection procedure. The passageway 19 allows 35 for suction/irrigation of fluids through the housing 12, which is controlled, for example, by a trumpet valve. This type of electrosurgical laparoscopic instrument is described in greater detail in U.S. Pat. No. 5,261,905, incorporated herein by reference. 40
One problem with this type of electrosurgical laparoscopic instrument 10 as well as other surgical instruments that provide suction/irrigation is that the passageway 19 is obstructed by the electrode 18 or other surgical tool disposed at the distal end 16 of the instrument 10. In the electrosur- 45 gical laparoscopic instrument 10, the electrode 18 includes a mounting portion 24 mounted within the passageway 19, for example, by welding to the inner surface 22. The mounting of the electrode 18 thus obstructs the passageway 19 and results in separate flow regions 19a, 19b, FIGS. 2 and 50 3, on either side of the mounting portion 24 of the electrode 18. As a result, the surgical instrument is unable to provide full flow of irrigating fluid during irrigation and does not provide a full passageway for suction of fluid and tissues.
Another drawback of mounting the electrode 18 or other 55 type of tool to the inner surface 22 within the passageway 19 of the housing 12 is the difficulty involved in cleaning the instrument. Tissue and other debris will often become lodged against the mounting portion 24 of the electrode 18 or other tool located within the passageway 19. Proper 60 cleaning of surgical instruments is important to allow the instruments to be reused safely. The rigid tools commonly used to free debris and clear the passageways within the instruments often cause damage to the instruments. For example, the insulation around the housing 12 may break or 65 become damaged, resulting in an unsafe electrosurgical instrument that cannot be reused or repaired.
A further drawback of the obstructed passageway is the inability to pass other surgical devices, such as, for example, a biopsy needle, through the passageway 19 at the distal end 16 of the surgical instrument 10 with the housing 12 acting as a guide. This capability would allow other surgical procedures, such as a biopsy procedure, to be performed at the surgical site more easily and less invasively without having to remove the instrument 10.
One attempt at solving this problem might be to weld the electrode 18 or tool to the outside of the housing 12. However, this increases the diameter unevenly and creates two outside diameters (ODs) on the cannula or housing 12, making it difficult to pass the cannula or housing 12 through a trocar. Further, the trocar typically includes a silicone seal that should fit snugly around the cannula to prevent site leakage. If the electrode 18 is welded to the outer surface of the cannula or housing 12, the electrode 18 might damage the seal or prevent the seal from fitting snug around the smaller OD of the cannula. A channel or dimple can be formed in the housing 12 to receive the electrode 18 and make the OD consistent, but this will affect the inside diameter (ID) and cause a partial obstruction within the passageway.
A further disadvantage of this electrosurgical laparoscopic instrument 10 and other such surgical instruments is the attachment between the electrode 18 and the inner surface 22 of the housing 12. One way of attaching the electrode 18, FIG. 4, to the inner surface 22 of the housing 12 is by laser welding the edges 26a, 26b of the mounting portion 24 by applying the laser generally in the direction of arrows 28. The laser welding, however, only welds the portions of the edges 26a, 26b that touch the inner surface 22 of the housing 12. If the edges 26a, 26b have any irregularities such as a non-linear edge 30a or a burr 30fc caused, for example, by stamping the electrode 18, the edges 26a, 26b may have insufficient contact with the inner surface and may not be adequately welded. Thus, welding the electrode 18 to the inner surface 22 of the housing 12 can result in a weak attachment, possibly causing the electrode 18 to fall out, for example, during cleaning. The same problem with the strength/durability of the attachment occurs when the electrode is welded or otherwise secured to the outside surface of the housing 12.
A further problem occurs as a result of the passage of electrical current through an electrode 18 that is welded to the inside or outside surface of the housing 12. The gaps that form between the electrode 18 and the housing 12 may cause arcing or capacitive coupling to other insulated uninsulated areas.
Some electrosurgical instruments have the electrode formed integrally with the housing. In these instruments, however, certain tip shapes and geometries are not possible, such as a ball-shaped tip that has a diameter larger than the wall of the cannula.
Accordingly, a surgical instrument is needed that provides full flow irrigation and suction, that can be properly cleaned without damaging the instrument and safely reused, and that allows passage of another instrument or pharmaceuticals through the passageway. In particular, a need exists for an electrosurgical instrument having an electrode that is mounted as part of the wall of the housing to provide a substantially unobstructed passageway, to provide a stronger attachment between the electrode and the housing, to improve electrical contact, and to provide a number of different tip shapes.
SUMMARY OF THE INVENTION
The present invention features a surgical instrument comprising an elongated housing having a proximal end, a distal