Surgical cutting instrument

A surgical cutting instrument such as for use in intraocular surgery having a handpiece with an elongate probe extending foward from it. The probe has an elongate stationary outer cutter with a port at its tip and an elongate inner cutter with a cutting surface coaxially disposed therein. The interior of the inner cutter communicates with a vacuum source. A spring and diaphragm assembly in the handpiece and powered by a low pressure pump causes the inner cutter to rapidly reciprocate axially in the outer cutter, and body material, such as vitreous material, drawn in through the port by the vacuum source is thereby chopped by the cutting surface and aspirated out of the patient's body through the handpiece. A large adjustment nut on the handpiece allows the size of the port to be easily adjusted. Irrigation fluid can be provided at the surgical site through an infusion cap which is adjustable both longitudinally and rotatably on the handpiece.

BACKGROUND OF THE INVENTION 
The present invention relates to surgical cutting instruments and more 
particularly to surgical cutting instruments used in ophthalmic surgery. 
It further relates to surgical cutting instruments for use in cutting and 
evacuating material from parts and organs of animal and human bodies. It 
also pertains to vitrectomy handpieces for providing irrigating and 
aspirating and cutting functions for cutting and removing vitreous, blood 
clots and other material from the eye during intraocular surgery, and to 
such handpieces which more particularly incorporate reciprocating cutters. 
Many surgical instruments have been designed in the recent past to said 
ophthalmic surgeons in removing vitreous, blood clots, cataracts, lenses 
and other matter from the eye. These instruments typically have an 
elongated probe defining a cutter at the distal end thereof, which is 
inserted into the body, for example into the eye through an incision in 
the cornea or sclera. The probe thereof is typically formed by coaxial 
inner and outer tubes wherein a port is provided in the outer tube 
adjacent the end and the inner tube moves relative thereto, and the inner 
and outer tubes cut the material as it is drawn in through the port. The 
excised tissue is aspirated by suction from the interior of the body part, 
such as the eye, possibly together with fluid, through the central lumen 
of the hollow inner tube, and is collected in a collection vessel. 
It has been found that when the inner tube motion is rotational relative to 
the outer tube that the vitreous and other materials are pulled or sheared 
while being cut. Thus, the current practice is to provide for the inner 
tube to reciprocate longitudinally relative to the outer tube and thereby 
provide a chopping or guillotine type of action to cleanly cut the 
vitreous body. Many methods are known for effecting this reciprocating 
movement of the inner cylinder including utilizing an electric motor or a 
pneumatic actuator positioned in the handpiece, and these include the 
devices disclosed in U.S. Pat. No. 4,246,902, to Martinez, and U.S. Pat. 
No. 4,674,502, the entire contents of both of which are hereby 
incorporated by reference. It is also known to use a bellows positioned in 
the handpiece with the inner cutting tube being secured to the bellows, 
and a means for alternately supplying compressed air and vacuum to the 
bellows. This arrangement is shown for example in U.S. Pat. No. 3,884,238, 
whose entire contents are also hereby incorporated by reference. It is 
further known to include on the surgical cutting tool an infusion sleeve 
or similar means for providing irrigation either during or separately from 
the cutting procedure. This irrigation means can bathe the surgical site 
in a physiological fluid and for ophthalmic surgery can maintain the 
intraocular pressure to prevent the collapse of the eyeball. 
These known cutting instruments though suffer from many disadvantages, 
including the difficulty in assembling them, excessive vibrations created 
by the handpiece, inability to attain cutting speeds greater than 600 cuts 
per minute, lack of suitable means for adjusting the size of the cutting 
and aspirating port, and the presence of outside moving parts on the 
handpiece. Thus, a need has arisen for an improved design for such 
surgical cutting instruments. 
Accordingly, it is a principal object of the present invention to provide 
an improved design for a surgical cutting instrument. 
Another object of the present invention is to provide an improved surgical 
cutting instrument construction which can be easily assembled and is 
designed to be economically disposable after a single use. 
A further object of the present invention is to provide an improved 
construction of a surgical cutting instrument having an infusion component 
which can be easily adjusted. 
A still further object of the present invention is to provide an improved 
surgical cutting instrument design which reduces the vibrations created by 
the handpiece thereof. 
Another object is to provide an improved vitrectomy handpiece having no 
moving parts outside of the body of the handpiece. 
A further object is to provide an improved surgical cutting instrument 
having greater cutting speeds for increased efficiency and safety. 
Other objects and advantages of the present invention will become apparent 
to those persons of ordinary skill in the art from the foregoing 
description taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings a preferred surgical cutting instrument of the 
present invention is illustrated generally at 10. Instrument 10 is shown 
in FIG. 1 to comprise a vitrectomy handpiece illustrated generally at 12 
connected to a low pressure twenty to thirty psi pump illustrated 
schematically at 14 providing a vacuum source 16 and a pressure source 18, 
and an irrigation source 20, such as a BSS bottle located at a 
predetermined height above the surgical site, providing a source of 
irrigation fluid. The bottle 20 is connected by a silicone or PVC tubing 
22 to the infusion fitting 24 on the infusion sleeve 26 portion of the 
infusion cap 28. A logo pad 29 to display the manufacturer's or 
distributor's logo is provided on and along the infusion cap 28. A 
silicone tubing vacuum line 30 is provided from the vacuum source 16 to 
the vacuum fitting 32 of the handpiece 12, and a silicone tubing pressure 
line 34 connects to a pressure line fitting 36. The vacuum fitting 32 and 
the pressure fitting 36 are both attached generally at separate locations 
to the distal end of the end cap 38 of the handpiece 12. 
The end cap 38 which is formed is formed of a medical grade plastic houses 
a diaphragm assembly shown generally at 40 (FIG. 2), and the diaphragm 
assembly 40 is secured to the inner cutting tube 42 which is adapted to 
reciprocate within the outer cutting tube 44. The outer cutting tube 44 
has a side port 46 adjacent its forward tip and has a cutting surface, and 
the inner cutting tube 42 has a cutting surface 47 at its distal tip which 
slides reciprocally relative to the port 46. Inner cutting tube 42 is 
hollow so that when suction is applied to it through the fitting 32, 
vitreous and other matter is drawn into the port 46 and the reciprocating 
inner cutting tube 42 chops the matter drawn into the port 46 in a 
quillotine fashion, and then aspirated out the inner cutting tube 42 
through the vacuum line 30, as illustrated for example in U.S. Pat. No. 
3,776,238, which is hereby incorporated herein. 
Simply explained, the diaphragm assembly 40 is caused to reciprocate back 
and forth by the action of pressurized air through the pressure line 34 
against the diaphragm assembly 40 in a forward direction, and the bias to 
the diaphragm assembly 40 in the opposite rearward direction is caused by 
the compressed bias spring 48 disposed in the chamber 50 of the assembly 
tip and body member 52 and also by the vacuum effect thereon from the 
vacuum source 16. The assembly tip and body member 52 can be also made 
from a medical grade plastic. 
The diaphragm assembly 40 in its retracted position is best illustrated in 
FIG. 2 and in its extended position in FIG. 3. It is seen from those 
figures that the diaphragm assembly 40 which is formed of silicone has a 
proximal expandable and contractable bellows portion 54, an integral 
diaphragm flange 56, and a separate diaphragm hub 58 disposed forward of 
the diaphragm flange 56 and in which the inner cutting tube 42 is secured 
by tube proximal outwardly-flaring flange 60. The bias spring 48 has its 
rearward end seated in the seat 62 formed by the diaphragm hub 58 and its 
forward end positioned against gasket 66. Gasket 66 in turn is sandwiched 
between the bottom of the major hole 68 in the body member 52 and the bias 
spring 48, and is provided to prevent air bubbles from forming in the 
vacuum line 30 by blocking air from passing between the inner and outer 
cutting tubes 42, 44. The diaphragm assembly 40 has a diaphragm passageway 
70 passing longitudinally therethrough as does the diaphragm hub 58 with 
its hub passageway 72, both of which define a passageway communicating the 
interior of the inner cutting tube 42 with the vacuum line 32 and through 
which a vacuum pressure is applied and out through which the cut vitreous 
materials are aspirated. 
Thus, during the reciprocating cycle when the pressure in the pressure line 
34 is not at its peak the spring 48 and the alternating sucking force in 
the pressure line 34 cause the diaphragm assembly 40, and thus the inner 
cutting tube 42 secured thereto and the spring, to be positioned in their 
rearward position, as best illustrated in FIG. 2. In this position the 
port 46 is open so that vitreous material can be sucked therethrough and 
into the tip of the inner cutting tube 42. Then when the pressure in the 
pressure line 34 is increased the pressurized air causes the diaphragm 
bellows portion 54 to expand and the diaphragm hub 58 to be pushed forward 
against the bias of the spring 48. The inner cutting tube 42 secured to 
the hub 58 is thereby caused to move forward so that its cutting surface 
47 passes in front of the port 46 and chops the drawn-in vitreous 
material. This forward position is best illustrated in FIG. 3. As the 
diaphragm moves forward, the air in the chamber 50 is expelled out of the 
body member 52 through relief holes 74, and sucked in through them when 
the diaphragm moves backward. The relief holes 74 are positioned so that 
they cannot be closed off as by the user's fingers or by other means. 
Adjustments to the size of the port 46 can be made by holding the end cap 
38 against rotation and turning clockwise or counterclockwise relative to 
the body member 52 the adjustment nut 76, which is threaded on the aft 
portion of the body member 52 and formed of a medical grade plastic. An 
annular adapter 78 also formed of a medical grade plastic is snap fitted 
tightly to the end cap 38, and thus, as the adjustment nut 76 is turned, 
the adapter 78, the end cap 38 and the diaphragm hub 58 are all moved 
forward or backward depending on the direction in which the adjustment nut 
76 is turned. As the diaphragm hub 58 is moved relative to the body member 
52, the longitudinal normal position of the inner cutting tube 42 relative 
to the outer cutting tube 44 is also adjusted. Due to this design the 
forward and backward movements of the diaphragm assembly 40 can be 
repeated up to eight hundred times a minute, which is considerably greater 
than the six hundred times per minute rate possible with most 
commercially-available surgical cutting instruments. The rotary movement 
of the adapter 78, diaphragm hub 58, and end cap 38 is prevented by 
built-in orientation means. 
The body member 52 has two round dimples 79a, spaced one hundred and eighty 
degrees apart. The adjustment nut 76 has twelve longitudinal lips 79b 
equally spaced on the internal surface between the threads and the distal 
end. The radial distance between two opposite lips is slightly smaller 
than the distance between the dimples. A click can be heard each time the 
adjustment nut 76 is turned thirty degrees in either the clockwise or the 
counterclockwise direction as the lips 79b of adjustment nut 76 are forced 
over the dimples 79a of body member 52. 
The construction of the diaphragm assembly 40 is thus unique in that it 
provides a diaphragm, bellows, sealing and free passageway functions all 
in one unit. It expands and contracts in its bellows portion 54 thereby 
providing flexibility and eliminating the need for any (stainless steel) 
aspiration tubes sticking outside of the end cap 38 as found on many prior 
devices, and in fact no moving parts outside of the body member 52 of the 
vitrectomy handpiece 12 are needed. Also, the very end 80 of the diaphragm 
assembly 40 outside of the body member 52, as shown in FIG. 4, comprises 
an assembly aid to easily thread the diaphragm through the hole in the 
back of the end cap 38, and to be cut off as at location 81 after 
threading the diaphragm through that hole. The diaphragm flange 56 is 
sandwiched between the end cap 38 and the adapter 78 to provide a good 
seal therebetween. It has been found that the diaphragm assembly also 
creates less vibration during its operation than experienced with other 
similar handpieces. 
The infusion cap 28 which is made of a medical grade plastic is adjustable 
in both longitudinal and circular directions relative to the body member 
52, as indicated by the arrows in FIG. 1. An O-ring 82 provides a seal 
against the infusion fluid that comes in through the infusion fitting 24 
and allows firm yet adjustable movements of the infusion cap 28 relative 
to the body member 52. The infusion or irrigation fluid then passes out 
the infusion sleeve 26 and out the coaxial opening 88 at the end of the 
sleeve adjacent the port 46. 
Since no O-rings are needed in the reciprocating drive aspect of this 
instrument 10, reduced drag results, the instrument is easier to operate, 
a lower air pressure of only twenty to thirty psi of pump 14 is needed, 
and no silicone oil is needed. Also because the body parts are snap-fitted 
together, assembly of handpiece 12 is easy and reliable and no adhesives 
or the like are required. 
Although the primary use of the subject surgical cutting instrument 10 is 
for ophthalmic surgery, namely irrigation and aspiration, anterior 
vitrectomy and posterior vitrectomy, surgical uses on or in other parts of 
the body are possible, including liposuction, back surgery, kidney stone 
surgery, gall bladder surgery, orthopedic surgery and reconstructive 
plastic surgeries. An example of a posterior vitrectomy handpiece of the 
present invention is shown in FIGS. 6-8 generally at 90. Handpiece 90 
corresponds generally to handpiece 12 except that it lacks an irrigation 
infusion capability and thus has a body sleeve construction as shown 
generally at 92 in place of the infusion cap 28. 
From the foregoing detailed description it will be evident that there are a 
number of changes, adaptations and modifications of the present invention 
which come within the province of those persons having ordinary skill in 
the art to which the aforementioned invention pertains. However, it is 
intended that all such variations not departing from the spirit of the 
invention be considered as within the scope thereof as limited solely by 
the appended claims.