The laproscopic trocar which takes the form of an elongated cannula through which to be inserted an elongated sharp pointed instrument. The tip of the instrument includes screw threads with the rear portion of the instrument including a crank assembly. Rotation of the crank assembly causes gradual penetration of the instrument through a patient's abdominal wall.

BACKGROUND OF THE INVENTION 
The field of this invention relates to medical instruments and more 
particularly to a laproscopic trocar which is in common use to penetrate a 
patient's abdominal wall with a minimum incision and permit the performing 
of certain surgical procedures through the cannula of the trocar. 
The surgical procedure of a laparoscopy is in common use at the present 
time. Such a surgical procedure normally employs the use of a trocar which 
is comprised of a cannula or sleeve through which is inserted a sharp 
pointed tool. This tool is to effect penetration of the abdominal wall 
thereby permitting the cannula to be inserted through the abdominal wall 
and remain in place and permit any one of several different types of 
instruments to be inserted through the cannula to perform surgical 
procedures within the patient's abdomen. Normally this type of procedure 
is frequently employed upon women to perform any one of numerous surgical 
procedures upon the female organs. 
The primary advantage to a laparoscopy is that only a small incision is 
required and a wide range of surgical procedures can be completed through 
the use of a laproscopic trocar. 
However, there are certain disadvantages to the conventional type of 
laproscopic trocar. The primary disadvantage is that a initial force is 
usually required in the inserting of the trocar. At times a significant 
force is required to achieve initial penetration through the abdominal 
wall and once initial penetration has been obtained, the trocar is easily 
insertable. As a result the physician is strenuously forcing to obtain 
insertion of the trocar and after initial insertion the trocar penetrates 
deeply into the persons abdomen. It is not at all unusual that this deep 
penetration results in an unnecessary injury within the patient's abdomen. 
Common types of such injuries are aortic and iliac artery lasceration. 
Also injuries to the internal organs are common. 
SUMMARY OF THE INVENTION 
The subject of this invention comprises a modification of a conventional 
laproscopic trocar structure wherein an elongated sharp pointed 
penetrating instrument is to be inserted through the elongated hollow 
cannula of the trocar. The instrument is to be telescopingly movable 
within the cannula. The sharp pointed end of the instrument includes a 
series of screw threads with the inner end of the instrument including a 
crank assembly. The sharp pointed end of the instrument, after being 
placed within the cannula, is to be placed into physical contact with the 
patient's abdominal wall. A slight pressure is to be applied against the 
instrument forcing such into snug contact with the abdominal wall. 
Subsequent rotation of the instrument causes the sharp point of the 
instrument to penetrate the abdominal wall with the screw threads 
permitting gradual entry of the instrument into the peritoneal cavity. The 
instrument is then withdrawn leaving in place the cannula. Various types 
of surgical and observation type instruments are to be insertable through 
the cannula permitting various types of surgical operations to be 
performed within the patient's abdomen. 
The primary objective of this invention is to construct a laproscopic 
trocar which is to be gradually inserted through the abdominal wall 
thereby eliminating the potential hazard in the employment of a 
conventional laproscopic trocar. 
A further objective of this invention is to modify the penetration 
instrument of the laproscopic trocar and to permit the penetrating 
instrument to be used on existing trocar equipment thereby not requiring 
the altering of substantial trocar structure.

DETAILED DESCRIPTION OF THE SHOWN EMBODIMENT 
Referring particularly to FIG. 1 there is illustratedly depicted the use of 
a prior art type of laproscopic trocar 10. The trocar 10 includes the use 
of a cannula or sleeve 12 within which is telescopingly received a sharp 
pointed instrument 14. The instrument 14 at the inner end thereof includes 
an enlarged section to facilitate manual grasping of the instrument 14. 
The outer end of the instrument 14 is sharp pointed to include a knife 
edge 16 to facilitate penetration through the abdominal wall 18 of the 
patient. The instrument 10 includes appropriate valving assembly 20 for 
the entry and release of gas within the peritoneal cavity. The 
construction of the valving assembly 20 is deemed to be conventional and 
forms no specific part of this invention. 
Referring particularly to FIGS. 2-5 there is shown the trocar 22 of this 
invention which is basically similar in construction to trocar 10 in that 
the cannula 24 is identical as well as the valve assembly 26. However, the 
sharp pointed instrument 28 not only includes a sharp pointed outer end 30 
but also includes a series of helical ridges forming a screw thread 
arrangement 32. 
Fixedly secured to the inner end of the instrument 28 is a crank wheel 34. 
Attached to the crank wheel 34 adjacent the periphery thereof there is a 
pin 36. A handle 38 is rotatably mounted on the pin 36. 
To operate the laproscopic trocar 22 of this invention the physician fully 
inserts the sharp pointed instrument 28 within the cannula 24 to the 
position shown in FIG. 2 of the drawing. The physician then places the 
point 30 against the patient's abdominal wall 18 and exerts a slight 
pressure against the wall 18 with the result that the point 30 makes an 
initial incision within the abdominal wall 18. The physician then holds 
fixed the cannula 24 and grasps the handle 38. The physician then rotates 
the wheel 34 which in turn causes rotation of the instrument 28. This 
rotation of the instrument 28 as well as the slight pressure toward the 
abdominal wall 18 produces a gradual cutting through the abdominal wall 
18. This cutting action is facilitated through the use of the screw 
threading assembly 32. 
Upon the tip of the instrument 28 having completely penetrated the 
abdominal wall 18 and being located within the peritoneal cavity, the 
forwardmost portion of the cannula 24 also extends within the cavity. The 
physician then removes the instrument 28 leaving the cannula 24 in 
position and therefore the cannula 24 is ready to have conducted 
therethrough other instruments to perform surgical operations within the 
peritoneal cavity. 
Reference is to be had to FIG. 5 wherein a modified form of tip 40 is shown 
of the instrument 28. The modification regarding the tip 40 relates to the 
having the screw threaded assembly 42 having a series of sharp pointed 
helical ridges adjacent the very tip 30 and then a series of smoothly 
controured helical ridges spaced from the sharp point 30. 
Within the embodiment shown in FIG. 3 the helical ridges 32 are all sharply 
pointed. It may be desirable to interpose alternatingly with the sharp 
pointed ridges a series of smoothly contoured ridges to minimize the 
tearing of the tissue as the instrument 28 penetrates the abdominal wall 
18. It is also considered to be within the scope of this invention that 
all of the helical ridges 42 be smoothly contoured rather than just some 
of the ridges 42.