Arthroscopic shaver with rotatable collet and slide aspiration control valve

A rotatable surgical shaver handpiece having a rotating elongated inner member within a fixed outer member is provided with a means for varying the cutting window orientation of the outer tubular member. The window orientation is adjusted by providing a rotatable collet assembly which has a hollow, outer, longitudinally movable body to which the outer hub member is keyed. The outer collet member is concentrically situated about an inner collet body and is fixed to an annular, toothed locking surface which is movably biased against an identical toothed locking surface fixed to the inner collet body. The teeth have sloped sides and are shallow such that the pre-loaded force compressing the two locking surfaces together is easily overcome by rotating the outer collet body to cause the teeth of one locking surface to slide along the teeth of the mating locking surface. In another embodiment, the invention is provided with a blade recognition means for identifying a code associated with a particular blade assembly regardless of the window orientation of the outer tubular member of the blade assembly. In another embodiment of the invention the handpiece is provided with an extruded body fitted with a longitudinally slidable aspiration control switch.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a surgical handpiece for use during endoscopic 
surgical procedures for driving an elongated rotatable surgical instrument 
and aspirating material from the surgical work site. More particularly, 
this invention relates to a method for manufacturing the handpiece and a 
means for enabling the orientation of the instrument attached to the 
handpiece to be angularly adjusted relative to the axis of the handpiece. 
The invention also relates to a surgical handpiece having a novel, 
longitudinally activated aspiration control valve. 
2. Description of the Prior Art 
Surgical handpieces have long been used to house the mechanical and 
electrical components necessary to operate a variety of powered surgical 
instruments attached to the handpiece. While some such instruments are 
used in open surgical procedures, the use of surgical cutting instruments 
has also become well accepted in performing closed surgery such as 
arthroscopic or more generally endoscopic surgery. The terms 
"arthroscopic" and "endoscopic" may be used interchangeably herein and are 
intended to encompass arthroscopic, endoscopic, laparoscopic, 
hysteroscopic or any other similar surgical procedures performed with 
elongated instruments inserted through small openings in the body. In such 
surgery, access to the surgical site is gained by one or more portals and 
instruments used in the surgical procedure must be elongated to permit the 
distal ends of the instruments to reach the surgical site. Surgical 
cutting instruments for use in closed surgery are commonly referred to as 
"shavers" or "blades" and comprise an assembly composed of a rotatable 
inner member situated within a non-rotatable outer member. Such shavers 
conventionally have an elongated outer tubular member terminating at a 
distal end having an opening in the side and/or end wall to form a cutting 
port or window. An elongated inner tubular member is concentrically 
disposed in the outer tubular member and has a distal end disposed 
adjacent the opening in the distal end of the outer tubular member. The 
distal end of the inner tubular member has a surface or edge for engaging 
tissue via the opening in the distal end of the outer tubular member and 
in many cases cooperates with the opening to shear or cut tissue. The 
inner and outer tubular members both have hubs at their proximal ends to 
enable the shaver blade assembly to be attached to a handpiece to 
facilitate manipulation of the shaver blade as well as to provide power to 
the inner tubular member so it can be rotatably driven at its proximal 
end. The drive mechanism is normally a small electric motor situated in 
the handpiece and controlled by a foot switch, a finger actuated switch on 
the handpiece or switches on a console supplying power to the handpiece. 
The distal end of the inner tubular member can have various configurations 
depending upon the surgical procedure to be performed and the opening of 
the distal end of the outer tubular member has a configuration to 
cooperate with the particular configuration of the distal end of the inner 
tubular member. Cut tissue and irrigating fluid are aspirated through the 
hollow lumen of the inner tubular member to be collected via a tube 
communicating with the handpiece. 
In such instruments, the cutting window at the distal end of the outer 
member is often fixed at a given angular orientation relative to the 
handpiece. The hub at the proximal end of the outer member is keyed to fit 
in a receiving collet having a keyway facing in only a particular 
orientation which necessarily causes the cutting window to face in a 
predetermined direction. The choice of where to position the keyway 
relative to other features on the handpiece is made during manufacture. 
However, in certain surgical procedures the surgeon may prefer to have the 
cutting window face in different directions relative to the handpiece, 
particularly if the handpiece has control switches or is shaped in a way 
which interferes with its use in certain window orientations. 
While some mechanisms are known by which the angular orientation of the 
cutting window is adjustable, such mechanisms are often cumbersome and are 
difficult to operate during the course of an endoscopic surgical 
procedure. One known cutting window orientation adjustment method involves 
simply providing multiple keyways (or bayonet locking mechanisms), 
removing the shaver blade and reinserting the hub into the collet in a 
different position. Another known method utilizes a single keyway to fix 
the window relative to the collet and means to enable the collet itself to 
be unlocked and turned without removing the blade. This method, utilized 
for example on a APS High Speed Arthrotome manufactured by Hall Surgical, 
Carpinteria, Calif., requires a procedure in which the handpiece body and 
collet are each held, moving the collet distally a certain distance 
relative to the body, turning the collet to orient the window as desired 
and then releasing the collet to lock it in place relative to the body. 
While not necessarily detrimental in an open surgical procedure, this type 
of adjustment may in some instances be awkward to perform during the 
course of an arthroscopic procedure. An easier window orienting mechanism 
would be desirable. 
While the ability to select the cutting window orientation is desirable, 
doing so with existing shaver blades destroys the blade recognition 
feature utilized in many arthroscopic shaver systems. This feature relies 
on encoding the blades with discrete magnets embedded in the hub of the 
outer tubular member and reading the position of these magnets with 
sensors in the handpiece. This information is used to control the speed of 
the drive motor and to perform other identification functions understood 
by those skilled in the art. Rotating the outer tubular member in order to 
orient the cutting window moves the magnets in the hub away from the 
sensors, thus providing inaccurate information to the control system 
operating the handpiece. It would be desirable to have the ability to 
orient the cutting window of a shaver blade without compromising the 
ability of the control system to read the code associated with the blade 
in use. 
The ability to control the orientation of the cutting window should be 
considered in conjunction with the necessity for the surgeon to control 
the degree to which irrigating fluid and tissue debris is aspirated from 
the surgical work site. This is generally accomplished by providing the 
surgeon with a handpiece having an easily accessible aspiration control 
valve. Thus, the surgeon could hold the handpiece comfortably with the 
aspiration control button in a selected orientation while being able to 
orient the cutting window as desired. While aspiration controls for shaver 
blade handpieces are known, they are often either expensive to manufacture 
or difficult to use because the design of these controls is greatly 
dependent upon the manufacturing process utilized for the body of the 
handpiece. For example, one known finger activated suction control valve 
utilizes a single, longitudinally extending lever pivoted at the surface 
of an elongated handpiece about an axis perpendicular to the longitudinal 
axis of the handpiece. The lever is rotatable in a plane parallel to the 
axis. Another example utilizes a similar lever near the distal end of the 
handpiece but pivoted about an axis parallel to the longitudinal axis of 
the handpiece. This lever is rotatable in a plane perpendicular to the 
axis. In each of these examples the user must employ a side-to-side, 
lateral type of finger motion to manipulate the suction control valve. 
Many surgeons prefer a suction control valve having an ergonomically more 
normal motion such as a forward/backward, longitudinal type of finger 
motion particularly if the handpiece is small and held like a pencil. One 
known forward/backward valve is in the form of a lever extending outwardly 
from the axis of the handpiece, the radially inner end of the lever 
attached to a rotatable apertured plug situated in a transverse channel 
drilled through the distal end of an axially aligned aspiration channel in 
a handpiece. The plug has a bore which, by rotation of the plug about its 
axis, is aligned in either an open or closed position by the 
forward/backward motion of the lever. Known handpieces having such a 
transverse control valve are expensive and difficult to manufacture. 
Prior art surgical shaver handpieces are generally machined from bar stock 
in view of the desire to minimize the number of throughbores and openings 
which must be sealed. This necessitates the use of the aforementioned 
transverse aspiration control valves. Even in those instances where 
handpieces have a main throughbore for the motor, blade, etc. and another 
parallel throughbore for the aspiration channel, the aspiration control 
valves are only laterally adjustable. 
It is consequently an object of this invention to produce a surgical shaver 
handpiece having a simplified longitudinally actuable aspiration control 
valve which is less costly and difficult to manufacture than known units. 
It is another object of this invention to produce a surgical shaver 
handpiece in which aspiration control may be achieved by a longitudinally 
movable slide switch. 
It is yet another object of this invention to produce a surgical shaver 
handpiece having a simplified longitudinally actuable aspiration control 
valve with a combination seal/bearing unit to support and seal the valve. 
It is also an object of this invention to produce a surgical shaver 
handpiece in which the orientation of the cutting window of the outer 
member is easily adjustable without disengaging the blade from the 
handpiece. 
It is yet another object of this invention to produce a surgical shaver 
handpiece in which the orientation of the cutting window may be changed 
while retaining the ability of the control system to read the code 
associated with the blade in use in any window orientation. 
SUMMARY OF THE INVENTION 
These and other objects of this invention are achieved by the preferred 
embodiment disclosed herein which is a surgical instrument for driving an 
elongated surgical tool having an inner member rotatably situated within 
an outer member, the outer member having a cutting window facing at least 
partially in a direction transverse to the axis. The instrument comprises 
a housing with a drive means within the housing to drive the inner member 
of the tool. A releasable collet means at the distal end of the housing 
receives the surgical tool and holds it longitudinally fixed relative to 
the drive means. The collet means is adapted to receive the outer member 
of the tool in a predetermined angular orientation relative to the axis of 
the housing. A rotation enabling means is provided for enabling rotation 
of the collet means in order to vary the predetermined angular orientation 
of the outer member. The rotation enabling means comprises a detent means 
to retain the collet in a selected position, the detent means being 
manually rotatable without being first manually urged longitudinally. The 
detent means comprises a first locking plate having a first locking 
surface facing in a distal direction and a second locking plate having a 
second locking surface facing in a proximal direction. The first and 
second locking surfaces engage each other to prevent relative rotation 
between the first and second locking plates. A hollow, outer cylindrical 
collet member is fixedly secured to the first locking plate and has a 
keyway for fixing the position of the outer member. A spring means is 
interposed between the outer collet member and the second locking plate 
for selectively maintaining the first and second locking surfaces in 
engagement. 
The invention is also embodied in an elongated surgical handpiece having a 
body with a proximal end and a distal end and the method of manufacturing 
same. The handpiece has a longitudinally aligned first bore extending 
between the proximal end and the distal end for containing a motor for 
driving a surgical instrument and a longitudinally aligned second bore, 
parallel to the first bore, for providing an aspiration conduit for 
aspirating material from the distal end to the proximal end. The method 
comprises the steps of providing an extrudable material, extruding the 
extrudable material with the first and second bores extending through the 
body and forming an oblique aspiration channel extending from said second 
bore distally to said first bore. The method further comprises providing a 
longitudinally movable aspiration control valve having an elongated pin 
sized to be axially received in the distal end of the second bore and 
sufficiently elongated to selectively occlude the oblique aspiration 
channel. A slide body is adapted to slidably retain the pin within the 
second bore and to seal the distal end of the second bore. 
The invention is also embodied in a surgical instrument for driving a 
rotatable surgical tool, the instrument comprising a housing having a 
drive means for driving the tool and a releasable collet means for 
receiving the tool and holding it fixed to the drive means. The collet 
means is adapted to receive the tool in a predetermined angular 
orientation relative to the housing. The instrument has a means for 
enabling rotation of the tool to vary the predetermined angular 
orientation and a recognition means for identifying the tool regardless of 
its angular orientation relative to the housing.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIGS. 1 through 5 there is shown a surgical shaver 
handpiece 10 constructed in accordance with the principles of this 
invention. Handpiece 10, constructed in a modular fashion to facilitate 
its assembly and repair, comprises a body 12 having a distal end 14, a 
proximal end 16, a collet assembly 18, a motor/seal assembly 20 and a 
cable assembly 22. As best seen in FIGS. 5 and 6, body 12 has two 
parallel, longitudinally extending throughbores: bore 24 is the main 
channel for receiving the motor/seal assembly 20 and collet assembly 18 
and bore 26 is an aspirating channel which is provided with a slidable 
suction control valve 28 at the distal end 14 of body 12 and a tubing 
adapter 30 at the proximal end 16. An oblique aspiration communication 
channel 27 extends distally from bore 26 to bore 24. 
As best seen in FIG. 6, body 12 has a tear-drop shape which, in the 
preferred embodiment, is formed by extruding an extrudable material 
(aluminum, plastic, etc.) with throughbores 24 and 26. Oblique channel 27 
and the annular grooves, threads and internal component receiving channels 
must be machined into body 12 after the extrusion step, but these are 
relatively minor manufacturing steps which are also employed in prior art 
non-extruded units. All known prior art handpieces are more expensive and 
time consuming to produce because they are machined entirely from a single 
bar of material. An additional advantage to extrusion is that, as will be 
understood below, it facilitates the use of a simplified slide aspiration 
control valve 28. 
The rotatable self-locking collet mechanism in handpiece 10 comprises 
collet assembly 18 which is shown in more detail in FIGS. 7a, b and c. As 
will be understood below, collet assembly 18 serves to secure handpiece 10 
to a shaver blade assembly, best seen in FIG. 14. 
Collet inner body 100 is formed from an integral, hollow piece of material 
having a distal cylindrical portion 102, an intermediate cylindrical 
portion 104, a shoulder 106 and a proximal threaded portion 108. 
Cylindrical portion 102 is provided with three ball detents 110 equally 
spaced around the periphery of cylindrical portion 102 (only one ball 
detent is shown in FIG. 7a). Cylindrical portion 104 is provided with 
three pin receiving apertures 112 (only one of which is shown) equally 
spaced around the periphery of cylindrical portion 104, the purpose of 
which will be explained below. Shoulder 106 is sized to smoothly abut 
collet body 100 against the distal opening 14 of handpiece body 12. 
Cylindrical threaded portion 108 is received in distal end 14 and secures 
the mounting of collet assembly 18 to handpiece body 12. 
Locking plate 120, best seen in FIGS. 7 and 13, is an annular ring having 
three equally spaced pin receiving apertures 122, a smooth proximally 
facing rear surface 124 and a toothed distally facing front surface 126. 
Locking ring 120 has an internal aperture 128 having a diameter sufficient 
to enable it to slide along intermediate cylindrical portion 104. An 
identical locking ring 130 is provided with three pin receiving apertures 
132, a distally facing rear surface 134 and a proximally facing front 
surface 136. The central aperture of locking ring 130 is also sized to be 
received on intermediate portion 104 although locking ring 130 is fixed to 
portion 104 by pins 113 inserted through pin apertures 132 and into 
apertures 112, as best seen in FIG. 8. 
As shown in FIG. 7b, once locking rings 120 and 130 are assembled onto 
collet body 100, a cylindrical pre-loading spring 140, sized to be 
received on cylindrical portion 102, is abutted against the distally 
facing rear surface of locking ring 130 and ball retaining ring 142 is 
then abutted against the distally facing side of spring 140. Balls 144 are 
then inserted into ball detents 110 as shown in FIGS. 7c and 9 and the 
entire assembly is held together by hollow, cylindrical outer collet body 
member 150 which is pinned via pins 153 to three equally spaced pin 
receiving apertures 152 to corresponding apertures 122 in locking ring 
120, as best seen in FIG. 10. Pre-loading spring 140 serves to cam balls 
144 into the locked position and also to urge locking plate 120 against 
locking plate 130 (note they are spaced in FIG. 7c for clarity). Thus, it 
will be understood that while outer collet body 150 is normally biased 
distally by spring 140, thereby causing the toothed surfaces of locking 
rings 120 and 130 to engage, collet body 150 may be caused to move 
rearwardly (proximally) in the direction of arrow A by mere rotation. The 
mechanical advantage of the locking rings allows direct turning of the 
outer collet body without pulling it proximally or pushing it distally. It 
will be understood that turning the collet body 150 causes the facing 
front surfaces of the locking rings to disengage, thereby enabling 
relative rotation of the locking rings. 
Outer collet body 150, best seen in FIGS. 11 and 12, has a hollow interior 
154 and an internal shoulder 156 which engages the distal side of ball 
retainer 142. A distal axially aligned aperture 158 is sized to receive a 
shaver blade assembly and is provided with a keyway 160 adapted to engage 
a corresponding key 192 on a shaver blade 172 best seen in FIG. 16. 
Referring briefly to FIG. 14, shaver blade assembly 172 comprises an 
elongated inner blade 174 and an elongated outer blade 176. Inner blade 
174 comprises an elongated tubular member 178 having a cutter 180 at its 
distal end and a hub 182 at its proximal end. Hub 182 includes a drive 
tang 184 to engage drive connection 185 of motor/seal assembly 120 (best 
seen in FIG. 5) to drive the inner member. Outer blade 176 comprises an 
elongated tubular member 186 having a cutting window 188 at its distal end 
and a hub 190 at its proximal end. Hub 190 includes a key tang 192 which 
fits into the keyway of the outer collet body member. 
Referring to FIGS. 13a and 13b, a detailed view of locking ring 120 shows 
that it has a central aperture 128 and a plurality of annularly arranged 
shallow teeth 125. The sides 126, 127 of adjacent teeth are separated by 
angle A which in the preferred embodiment is on the order of 119.degree.. 
The shallow design of the teeth enables the locking rings to be easily 
rotated relative to one another without first having to push outer collet 
body longitudinally rearwardly to disengage the teeth. The teeth of one 
locking ring slide along the teeth of the other locking ring merely by 
manually rotating the outer collet body. The annular array of 24 teeth 
enables the collet to be adjustable throughout 360.degree. in increments 
of 15.degree.. 
A slide aspiration control valve 28, best seen in FIGS. 1, 4, and 15a and 
15b, comprises a three sided slide body 194 having an end wall 195, an 
arcuate side wall 196 which has an inner surface 197 shaped to conform to 
the arcuate outer surface 198 of body 12 adjacent channel 26 as best seen 
in FIG. 6. End wall 195 has a pin 199 extending perpendicularly therefrom, 
pin 199 adapted to engage the distal end of throughbore 26 as best seen in 
FIG. 5. End wall 195 is provided with a pair of apertures 200 and 201 to 
receive pre-loaded springs (not shown) for maintaining the slide body in 
position in detent pairs 202a, 202b and 203a and 203b formed into the top 
of body 12. A combination cylindrical seal/bearing 205, best seen in FIG. 
16, is situated at the distal end of bore 26 and cooperates with pin 199 
to seal bore 26. Pin 199 is slidable in seal/bearing 205 has an oblique 
end face 206 and oriented in alignment with oblique channel 27 to 
facilitate the flow of aspirated fluid from bore 24 through oblique 
channel 27 to bore 26. It will be understood that the various positions of 
slide 28 in FIGS. 1, 2 and 3 correspond to various degrees of opening of 
the port or aperture formed by the intersection of channels 26 and 27. 
FIGS. 17 and 18 show an alternate embodiment of the invention in which a 
shaver blade handpiece is provided with a blade recognition feature 
suitable for identifying a coded blade in all angular positions relative 
to the housing. Handpiece 300 is identical to handpiece 10 in all respects 
other than the structure of the distal end 302 related to blade 
recognition. The distal end 302 Of handpiece 300 is provided with an 
aperture 304 in its side wall through which a hub pick-up lever 306 
extends inwardly. Hub pick-up lever 306 is attached to the bottom of a 
sliding magnet carrier 316 held within housing 308 secured to the outside 
of housing 300. Hub pick-up lever 306 has a distal end 310 situated 
internally within handpiece 300 in order to contact the proximal end of 
outer hub 311 of a blade assembly. Hub pick-up 306 is attached at its 
proximal end 312 to magnet carrier 316 which supports a magnet 318 and 
slides within a longitudinally extending channel 320 in magnet housing 308 
against the bias of spring 322. Also situated in magnet housing 308 are 
reed switches or Hall sensors 324 and 326 which are spaced longitudinally 
along channel 320. It will be understood that as hub pick-up 306 is 
longitudinally moved to varying degrees by its interaction with the 
proximal end of the outer hub of a blade assembly, the magnet 318 will be 
placed proximally to either switch/sensor 324, switch/sensor 326 or 
beyond. The position of magnet 318 relative to switches/sensors 324 and 
326 represents the code identifying the particular blade assembly, which 
code may be defined and communicated via wires 328 to a control console 
(not shown). The particular embodiment described in FIGS. 17 and 18 
requires the length of the outer hub 311 of each blade assembly to vary as 
a function of the code to be associated with a particular blade assembly. 
Yet another alternative embodiment of a blade recognition system is shown 
in FIG. 19 wherein an annular indicator is situated on the exterior 
surface of the hub of a blade assembly. Such an annular indicator would be 
longitudinally fixed and would be recognized by an associated sensor fixed 
within the housing of the handpiece regardless of the angular orientation 
of the outer hub to the handpiece. This arrangement would not require 
changes in the lengths of the hubs of the outer tubular members from one 
type of blade to the next. The code would be represented by the presence 
or absence of the annular indicator in the annular band sensed by a 
particular sensor on the housing. In FIG. 19, only the distal end of 
handpiece 400 is shown in engagement with the proximal end 402 of a blade 
assembly (not shown) having an outer hub 404. The unpictured portions of 
handpiece 400 and the blade assembly are identical to similar components 
previously discussed and need not be further described. Hub 404 comprises 
annular indicators 406 and 408 spaced longitudinally along the external 
surface of hub 404. Housing 400 has sensors 410 and 412 situated in 
proximity to the positions that annular indicators 406 and 408, 
respectively, will be in when hub 404 is fully seated in the handpiece. 
Sensors 406 and 408 are connected in a conventional manner by wires 414 to 
a control system. The number and spacing of the annular indicators may be 
varied provided there is a sensor situated to sense the presence or 
absence of an indicator at a defined position on the hub. For example, an 
array of any number of sensors similar to 410 and 412 could be provided to 
read the code defined by the presence or absence of annular indicators in 
any of the positions corresponding to (i.e. proximate) to the sensors. If 
annular indicators 406 and 408 are magnetic (for example, flexible 
magnetic strips or more rigid annular magnets) the sensors 410, 412 could 
be reed switches or Hall sensors. If indicators 406,408 are metal rings, 
sensors 410, 412 could be eddy current sensors. If an annular indicator 
other than a magnet or metal is used, for example, a light reflective 
surface, the sensor would necessarily be receptive to emanations from the 
indicator. One example of such an annular non-magnetic, non-metallic 
indicator may include an annular band on the surface of hub 404 which may 
contain an optically readable code. The code, repeated about the 
periphery, could be illuminated by a light source in the handpiece and the 
reflected light could be detected by a detector properly positioned in the 
handpiece. 
It will be understood by those skilled in the art that numerous 
improvements and modifications may be made to the preferred embodiment of 
the invention disclosed herein without departing from the spirit and scope 
thereof.