Surgical needle assembly and apparatus for attachment on a surgical needle assembly

A needle assembly for hand-held use in performing medical procedures having a first needle having a hollow shaft, the shaft having a pointed tip having a surface disposed at a predetermined angular relation to the longitudinal axis of the shaft; a second needle dimensioned for close-fitting removable insertion within the shaft; locking means for retaining the first and second needle in a fixed attitude relative to each other; and guide means adapted to indicate the attitude of deployment of the tip during use of the needle assembly in medical procedures. Also, an apparatus adapted for attachment on a conventional needle assembly for indicating the disposition of the tip thereof and for manipulating the needle assembly in an operative environment.

FIELD OF THE INVENTION 
The present invention relates to a needle assembly for use in medical 
procedures and the like and more particularly to such an assembly adapted 
for intervening within human intervertebral disc tissue for the 
introduction of diagnostic and therapeutic fluids therein. 
DESCRIPTION OF THE PRIOR ART 
The medical profession has long sought effective methods in the diagnosis 
and treatment of herniated vertebral discs, and particularly such 
herniations located in the lumbar region of the spine. The therapeutic 
course chosen for a given patient may be conservative, aggressive, or a 
combination of both. Among the more conservative forms of treatment are 
confining the patient to bed, restricting the patient's activities, and 
providing analgesic therapy for relief from pain. The more aggressive 
course of therapy often involves surgical intervention to remove the 
herniated disc in whole or in part. 
Such methods, while indicated in a number of situations, suffer from a 
variety of drawbacks and inadequacies. Restriction of the patient to bed 
forces the patient to refrain from work, recreation, and other normal 
daily activities which may require ambulation. The inconveniences and 
hardships occasioned by such confinement of the patient are myriad. 
Analgesic therapy, although effective in some cases in alleviating lower 
back and leg pain, is more often directed toward an amelioration of 
symptoms rather than a prevention of their cause. Surgical techniques, 
such as laminectomies and the like, are frequently resorted to only after 
more passive therapeutic methods have been exhausted, and the 
post-operative course of the patient is frequently attended by prolonged 
periods of discomfort, pain, and immobility required to permit healing. It 
is also well known that such surgery often necessitates the use of 
anesthesia, the risks of such use being preferably avoided. 
Relatively recent in origin is a technique known as chemonucleolysis which 
was developed for use primarily in treating herniated discs. The technique 
is well known as being associated with few of the known drawbacks commonly 
associated with the traditional therapeutic methods. In essence, the 
chemonucleolysis technique involves the insertion of a needle into the 
tissue of the herniated portion of the intervertebral disc to permit the 
delivery of an enzyme, such as chymopapain or the like to the operative 
site to digest or shrink the extruded tissue. It is desirable that the 
enzyme be injected only into the extruded disc material and, therefore, 
precise deployment of the needle tip is necessary to insure accurate and 
controlled delivery of the fluid enzyme carrier. 
In diagnosed situations in which chemonucleolysis is indicated, the need 
for surgery and a protracted post-operative convalescent course are often 
obviated. Patients treated using this technique frequently are permitted 
to become ambulatory on the same day on which the treatment occurs, and 
post-treatment back and leg pain is usually minimized. Further, the 
patient can more readily resume normal daily activities, including the 
performance of work. 
The surgical needle assemblies known in the prior art and employed in 
performing the technique of chemonucleolysis are commonly comprised of two 
needles: a first, outer needle or cannula; and a second, inner needle or 
stylet. The cannula has an elongated, tubular shaft having an interior 
bore of predetermined diameter throughout its length. At one end, the 
cannula has a beveled tip providing an apertured surface disposed in 
predetermined angular relation to the longitudinal axis of the shaft. 
Fluid transmitted through the bore is known to tend to follow a flow path 
relative to the longitudinal axis substantially corresponding to the 
angular disposition of the apertured surface upon exit therefrom. At the 
opposite end, the cannula has a hub portion providing a cavity of greater 
diameter than that of the bore. The stylet has an elongated shaft 
dimensioned for slidable insertion within the bore of the cannula and 
mounts a neck portion adapted to be received within the cavity of the 
cannula hub portion when the stylet shaft is inserted within the cannula 
bore. Remote from the stylet hub portion is its tip, the tip commonly 
being beveled similarly to the beveled tip of the cannula, whereby the 
respective beveled tips provide facing surfaces which lie in a 
substantially common plane when the shaft of the stylet is fully inserted 
within the bore of the cannula. An embossed portion of the stylet hub 
portion is sometimes provided to engage a similarly dimensioned notch or 
groove in the hub portion of the cannula, thus providing a means for 
insuring insertion of the stylet within the cannula in a predetermined 
attitude relative to it. In some needle assemblies, the cannula or stylet 
may be grooved, embossed, or otherwise marked with a form of indicium 
intended to remain in fixed, known relation to the angular disposition of 
the beveled tips, such indicia being adapted to remain outside of the 
bodily tissues during the performance of the technique, whereby reference 
may be had thereto in order to ascertain the direction in which the facing 
surfaces of the tips are disposed when such is not visible. 
The needles heretofore known in the art suffer a number of drawbacks and 
deficiencies. For instance, in view of the aforementioned tendency of 
fluids to follow a substantially known flow path relative to the 
longitudinal axis of the needle shaft, in performing chemonucleolysis and 
related intervertebral disc therapy, it has been known that it would be 
desirable to be able precisely and accurately to deploy the beveled tip in 
a predetermined attitude within a predetermined region of the spinal disc 
tissue, whereby the fluid can accurately and controlledly be introduced 
primarily into the tissue to be treated. Moreover, in passing the tip of 
the needle through the bodily tissues surrounding the spinal disc, it is 
often necessary to maneuver the tip around and over various bony 
prominences of the vertebrae themselves as well as portions of the spinal 
nerves eminating from the spinal canal. It has been found that the beveled 
tip of the conventional needle assemblies acts much in a fashion of the 
curved tip portion of a snow ski or the like: that is, the tip has a 
tendency to ride away from material encountered by its surface. Such 
tendency may most advantageously be exploited by the user of the needle 
assembly only if means are provided for both instantaneously determining 
the disposition of the surface of the beveled tip and for transmitting 
directed force precisely to manipulate the beveled tip throughout a wide 
range of attitudes. However, such means have heretofore not been known in 
the prior art and, therefore, the full benefits of intradiscal therapeutic 
techniques such as chemonucleolysis have been difficult, if not 
impossible, to obtain employing conventional needle assemblies. 
Further, in many procedures employing a dual needle assembly, the assembly 
is first inserted as a unit, the inner needle being then grasped by its 
head or neck portion and withdrawn to permit the injection of fluids 
through the outer needle via a syringe or the like. Inasmuch as 
chemonucleolysis and like procedures are commonly performed employing 
sterile technique, grasping the head portion may present a potential 
contamination risk. 
Subsequent to such injection, the inner needle is reinserted, and the 
assembly is left in place for a predetermined period of time. However, it 
has been found that the fluid so injected often creates back pressure on 
the assembly, resulting in displacement of the inner needle and consequent 
leakage of fluid from the treated area. Insofar as applicant is aware, no 
needle assembly known in the art provides means for preventing such 
displacement. 
Therefore, it has long been known that it would be desirable to have a 
needle assembly adapted to permit the precise and accurate delivery of 
fluids into predetermined bodily tissue areas and which provides the user 
thereof with means for continuously and simultaneously determining the 
disposition of the tip of the assembly within the bodily tissue and for 
precisely manipulating the tip for the directed movement thereof through 
such tissue. Further, it has long been known that it would be desirable to 
have a needle assembly which can securely and selectively be deployed in a 
locked attitude to prevent accidental or casual disengagement of the 
assembly components. 
OBJECTS AND SUMMARY OF THE INVENTION 
Therefore, it is an object of the present invention to provide an improved 
surgical needle assembly having a longitudinal axis and a tip disposed in 
predetermined angular relation thereto for hand-held and manipulated 
insertion within bodily tissues and which is capable of being so 
manipulated and inserted with a precision heretofore unobtainable. 
Another object is to provide such an assembly which provides means capable 
for permitting continuous and reliable ascertainment by a user thereof of 
the attitude of deployment of the tip when such is inserted within bodily 
tissues and is not visible. 
Another object is to provide such an assembly having means for retaining 
the component needles thereof against accidental disengagement thereof 
when deployed in an operative attitude. Another object is to provide such 
an assembly which can be employed with minimal risk of contamination 
during use thereof in medical procedures. 
Another object is to provide such an assembly which is adapted for use in 
medical procedures requiring the delivery of fluids into bodily tissues 
and which is adapted to minimize the possibility of accidental leakage of 
such fluids from such bodily tissues when the assembly is inserted within 
the tissues. 
Another object is to provide such an assembly of such durable construction 
as virtually to preclude damage thereto or deterioration thereof during 
its lifetime. 
Another object is to provide such an assembly which enables the full 
exploitation of therapeutic procedures such as chemonucleolysis which 
require extremely accurate, directionally controlled transmission of 
fluids into bodily tissues. 
Another object is to provide such an assembly which is characterized by 
ease of deployment, simplicity of construction, and which can be sold at a 
nominal price. 
Another object is to provide such an assembly which is compact and capable 
of being effectively held and manipulated in one hand by the user thereof. 
Another object is to provide an apparatus which can be deployed upon a 
conventional needle assembly to provide such assembly with many of the 
manipulative advantages obtained by the preferred embodiment. 
Another object is to provide such an apparatus which can be deployed in a 
known relation to the longitudinal axis of a conventional needle assembly 
having an angularly disposed tip whereby the attitude of deployment of 
such a tip within bodily tissues can be ascertained by reference to such 
guide member. 
Another object is to provide such an apparatus which can be constructed so 
inexpensively as to be disposable after single uses thereof. 
Further objects and advantages are to provide improved elements and 
arrangements thereof in an assembly and guide member for the purposes 
described which are dependable, economical, durable and fully effective in 
accomplishing their intended purposes.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Surgical Needle Assembly 
Referring more particularly to the drawings, the needle assembly embodying 
the principles of the present invention is shown in perspective in FIG. 1 
and is designated generally by the numeral 10. As shown therein, the 
needle assembly generally provides a first needle, or cannula 11, and a 
second needle, or stylet 12. 
As can best be seen in FIGS. 2 and 3, the cannula 11 has an elongated shaft 
20 of predetermined length measured along a longitudinal axis 21. The 
shaft provides a passage or bore 22 of predetermined diameter extending 
axially therethrough from a hub end portion 23 to a delivery end portion 
24, substantially coincident with the longitudinal axis. 
As can best be seen by reference to FIGS. 2, 3 and 4, the delivery end 
portion 24 has an outer edge 30 and an inner edge 31 disposed in a 
substantially common plane and defining a pointed tip 32 having a surface 
33 bounding an aperture 34. The surface 33 is disposed in predetermined 
angular relation to the longitudinal axis 21. Although the angle, or 
bevel, of the surface 33 may be varied, it is preferable that the surface 
be disposed at an angle ranging from about 22.degree. to about 30.degree. 
in relation to the longitudinal axis 21, for use of the assembly in 
performing techniques such as chemonucleolysis and the like. 
The hub end portion 23 of the shaft 20 mounts a hub 40 dimensioned to be 
grasped in the fingers of a user thereof. The hub provides a substantially 
cylindrical wall 41 bounding a cavity 42 communicating between the bore 22 
of the shaft 20 and an exterior opening 43 bounded by an endmost shoulder 
portion 44. 
The hub 40 providing a locking channel 50 of substantially L-shaped 
configuration cut within the wall 41. The locking channel has a primary 
slot 51 disposed substantially parallel to the longitudinal axis 21 and 
extending from the shoulder portion 44 incompletely toward the hub end 
portion 23 of the shaft 20. Continuous with and substantially 
perpendicular to the primary slot is a secondary slot 52 disposed 
circumferentially approximately one-quarter of the distance around the 
wall 41 of the hub 40. the secondary slot has a terminus 53. 
The stylet 12 provides an elongated, solid shaft 60 of predetermined length 
substantially symmetrical about a longitudinal axis 61. The shaft has a 
first end portion 62 and an opposite, second end portion 63. The first end 
portion 62 terminates in a tip 64 having a surface 65 disposed in 
predetermined angular relation to the longitudinal axis 61. In the 
preferred embodiment of the present invention, the angle defined by the 
surface of the tip 65 and the longitudinal axis 61 is substantially equal 
to that defined by the surface 33 of the tip 32 of the cannula shaft 20 
and the longitudinal axis 21 of the cannula shaft. It is preferable that 
the shaft 60 be dimensioned for close-fitting, removable insertion within 
the bore 22 of the cannula, whereby the bore can be substantially occluded 
by the insertion of the stylet shaft therein. 
The second end portion 63 of the stylet shaft 60 mounts a handle member 70. 
The handle member provides a neck portion 71 and a head portion 72. The 
neck portion is dimensioned for substantially close-fitting removable 
insertion within the cavity 42 of the hub 40. A shoulder-engaging portion 
73 is provided intermediate the neck portion 71 and the head portion 72, 
whereby upon substantially complete insertion of the neck portion within 
the cavity 42, the shoulder-engaging portion 73 is disposed substantially 
in close-contact with the shoulder 44 of the hub 40, and the head portion 
72 is disposed substantially external of the cavity 42. 
A locking post or pin 80 is mounted on the neck portion 71 substantially 
perpendicularly to the longitudinal axis 61 of the shaft 60. The locking 
pin is dimensioned closely to be received within the locking channel 50 
upon insertion of the neck portion 71 within the cavity 42 of the hub, and 
is adapted tensively to be retained in captured relation within the 
terminus 53 of the secondary slot 52 upon disposition therein. 
Mounted on the head portion 72 is a substantially transversely projecting 
arm or guide member 90. In the preferred embodiment of the present 
invention, the guide member has a substantially flat portion 91, disposed 
substantially perpendicularly to the longitudinal axis of the stylet shaft 
60, and a substantially curved portion 92, both portions providing a 
scored surface 93. The curved portion extends substantially outwardly, 
curving rearwardly away from the head portion 72. As can best be seen by 
reference to FIGS. 3 and 4, the guide member 90 is deployed in a fixed, 
predetermined relation to the locking pin 80 and the surface 65 of the tip 
64 of the shaft 60. In the preferred embodiment, the guide member 90 is 
aligned with the locking pin 80 and projects remotely from the surface 65 
of the tip 64 relative to the longitudinal axis 61. Thus, the disposition 
of the surface of the tip relative to the longitudinal axis can be 
determined continuously by reference to the disposition of the guide 
member 90. 
Alternative means for lockably engaging the cannula 11 and stylet 12 in an 
operative attitude are illustrated in FIGS. 10, 11, 12 and 13. As shown 
therein, the locking pin 80 is removed from the neck portion 71 of the 
stylet 12. The shoulder-engaging portion 73 mounts a locking member 100 
having a tongue portion 103 of predetermined length extending 
substantially parallel to the longitudinal axis 61 and spaced from the 
neck portion 71. The tongue portion 103 provides a depending tab 106 
disposed normally to the longitudinal axis and, together with the tongue 
portion and the shoulder-engaging portion 73, the tab defines a notch 108 
of predetermined dimensions. Preferably, the tongue portion 103 is 
disposed approximately 90.degree. about the longitudinal axis from the 
curved portion 92 of the guide member 90. It is desirable that the locking 
member be constructed of resilient metal, plastic or other suitable 
material. 
The shoulder portion 44 of the hub 40 of the cannula 11 is replaced by a 
substantially rectangular flange 110 having substantially rounded corners 
113 and four edges 115. Three of the edges are dimensioned to extend from 
the wall 41 in the manner of a lip. A fourth edge 117 is substantially 
linear and has a portion substantially tangential with the curvature of 
the wall 41. The fourth edge 117 provides an indicator slot 118 for 
alignment of the locking member 100 in the operation of the needle 
assembly 10, as is described in greater detail below. 
The wall 41 is scored to define a substantially flat groove 119 of 
predetermined dimensions disposed substantially perpendicularly to the 
longitudinal axis 21 and further disposed substantially perpendicularly to 
the fourth edge 117. Preferably, the flange 110 has a thickness in a 
longitudinal dimension adapted to permit the substantially close-fitting 
capturing thereof within the notch 108 of the locking member 100. Further, 
the groove 119 of the wall 41 is dimensioned for disposition of a portion 
of the tab 106 of the locking member 100 therein when the needle assembly 
10 is disposed in an operative attitude. 
As is described in greater detail hereafter, the needle assembly 10 finds 
greatest utility in permitting accurate deploymen of the tip 32 within 
soft tissue, such as intervertebral discs 120 while avoiding environmental 
anatomical sturctures, such as bony prominences 121, spinal nerves 122 and 
the like, such as are illustrated in FIG. 9. 
APATUS FOR ATTACHMENT ON A NEEDLE ASSEMBLY 
The apparatus of the present invention is designated generally by the 
numeral 150 in FIGS. 7 and 8. As shown therein, the apparatus, or cap 
member 150, is adapted to be deployed on the head portion 151 of a 
conventional surgical needle 152, shown fragmentarily in FIG. 8. It is 
preferable, although not necessary, that the cap member be constructed of 
a suitable synthetic material having moderate resiliency, thus enabling 
low production costs and permitting the cap member to be disposable after 
use. The cap member provides a body portion 155 and a guide portion 157. 
The body portion has walls 160 which can be configured as needed 
substantially closely to conform to the configuration of the head portion 
151 of a particular surgical needle for which the cap member is designed. 
The walls 160 define a cavity 163 bounded by a lip 166 dimensioned to 
permit the cap member 150 to be removably snap-fitted upon the head 
portion 151 in capturing relation thereto. 
The guide portion 157 of the cap member 150 is constructed substantially 
similarly to the guide member 90 of the needle assembly 10 of the 
preferred embodiment. The guide portion provides a substantially flat 
section 170 unitary with and surmounting the walls 160 and a curved 
extending section 172 projecting outwardly and away from the body portion 
155. Thus, the cap member 150 can be deployed upon the head portion 151 of 
a conventional surgical needle to dispose the extending section 172 in a 
predetermined relation to the longitudinal axis thereof, and can enable 
the user of a conventional surgical needle to manipulate it substantially 
in the fashion of the improved needle assembly 10 of the present 
invention, as is described in greater detail below. The extending section 
172 provides a surface 175 which is scored to afford an enhanced degree of 
friction upon engagement of a user's finger thereby. 
OPERATION 
The operation of the described embodiment of the present invention is 
believed readily apparent and is briefly summarized at this point. 
In assembling the needle assembly 10 prior to use in a medical procedure 
such as the chemonucleolysis technique referred to previously, the cannula 
11 can be grasped manually by the user thereof while the stylet 12 is also 
manually grasped. The tip 64 of the stylet is introduced through the 
exterior opening 43 of the hub 40 of the cannula and is then passed 
through the hub cavity 42 and inserted into the bore 22 of the cannula. 
The shaft 60 of the stylet is then passed through the bore 22. As the neck 
portion 71 is brought into proximity with the exterior opening 43, the 
locking pin 80 is aligned with the primary slot 51 of the locking channel 
50. As the shaft is continued to be passed through the bore 22, the 
locking pin 80 is passed along the locking channel primary slot 51 until 
the neck portion 71 is fully inserted within the cavity 42 of the hub and 
engages same. The stylet 12 is then manually rotated about its 
longitudinal axis 61 to carry the locking pin 80 along the secondary slot 
52 into engagement with the terminus 53 of the locking channel. The needle 
assembly 10 is thereby deployed in a locked attitude wherein the shafts 20 
and 60 of the cannula 11 and the stylet 12, respectively, are disposed 
substantially coaxially. Further, in the locked attitude, the curved 
portion 92 of the guide member 90 is disposed in a predetermined 
relationship to the disposition of the surface 33 of the tip 32 of the 
cannula. The surface 33 and the curved portion 92 are thereby disposed 
substantially diametrically oppositely of each other about the 
longitudinal axes. 
In the locked attitude, the needle assembly 10 can be manipulated as a 
unit, whereby manipulative force applied to the guide member 90, the hub 
40, or the head portion 72 of the stylet will cause simultaneous resulting 
movement of both the stylet and the cannula. 
The assembly 10 can be selectively disengaged by grasping the curved 
portion 92 of the guide member 90 and applying rotational force to the 
stylet about its longitudinal axis, whereby the locking pin 80 is moved 
along the locking channel 50. 
In performing medical procedures involving the delivery of fluids into 
bodily tissues, the needle assembly 10 is first deployed in the locked 
attitude prior to insertion of the tip 32 into the tissues. 
For purposes of manipulating the needle assembly as it is directed through 
the bodily tissues, the guide member 90 may be most advantageously 
employed by the user of the needle assembly by placing the index finger of 
the hand used to grasp the assembly against the surface 93 of the guide 
member, thereby permitting the index finger simultaneously to assist in 
the manipulation and application of force to the needle assembly and to 
act as a tactile means of sensing the direction of deployment of the 
surface 33 of the tip 32. As has been discussed above, the angular nature 
of the surface 33 causes the tip to plane away from tissue encountered 
thereby. As shown in FIG. 9, the tip 32 can thus be deployed within an 
intervertebral disc 120 after having been passed through bodily tissues 
and circumventing bony prominences 121 and spinal nerves 122. Thus, it can 
be readily appreciated that visualization of the progress of the tip of 
the assembly through the bodily tissues by use of fluroscopic or other 
radiologic imaging devices can be coordinated with great facility with the 
tactily indicated orientation of the needle assembly guide member 90. 
Further, it may be readily seen that minute changes in the course of the 
tip through the bodily tissues can be effected easily and continuously 
without interruptions for visual checks of the indicator means on the 
needle assembly. Thus, not only is the maneuverability of the needle 
assembly increased, but the precision of deployment of the tip is enhanced 
for the user thereof as well. 
Further, the novel means provided for maintaining the needle assembly in a 
locked attitude insures that back pressure from fluid injected into the 
bodily tissues will not cause the stylet to be forced from the bore of the 
cannula with possible resulting leakage and loss of therapeutic fluids. 
Deployment of the needle assembly 10 incorporating the alternative locking 
means illustrated in FIGS. 10, 11, 12 and 13, is substantially similar to 
that of the needle assembly described immediately above. That is, 
preliminarily, the tip 64 of the stylet is introduced through the exterior 
opening 43 of the hub 40 of the cannula and is then passed through the hub 
cavity 42 and inserted into and through the bore 22 of the cannula. As the 
neck portion 71 is brought into proximity with the exterior opening 43, 
the locking member 100 and, more particularly, the tab 106 thereof, are 
aligned with the indicator slot 118 of the flange 110. The stylet is 
passed axially until the neck portion 71 is fully inserted within the 
cavity 42 of the hub. The stylet is then rotated about its longitudinal 
axis 61 in the direction of the portion of the wall 41 bearing the groove 
119. The tongue portion 103 of the locking member 100 is thus caused to 
ride up and over the rounded corner 113 disposed between the fourth edge 
117 and the edge 115 corresponding to the portion of the wall 41 bearing 
the groove 119. Upon overcoming the corner, the tongue portion 103 and tab 
106 of the locking member 100 resiliently rebound to dispose the edge 115 
within the notch 108 and with the tab tightly inserted within the groove 
119. Thus, the entire needle assembly 10 can be manipulated about the 
longitudinal axis as a unit without disengagement of the stylet and 
cannula either rearwardly due to back pressure or the like, or due to 
rotary forces directed tangentially to the longitudinal axis. The needle 
assembly can then be utilized in the manner described above. 
The operation of the apparatus 150 of the present invention is also 
believed apparent. To utilize the apparatus, the body portion 155 is 
snap-fittingly deployed on the head portion 151 of a conventional needle 
assembly 152 with the head portion captured within the cavity 163. The 
curved, extending portion 172 is utilized to greatest advantage by 
deploying it in known relation about the longitudinal axis to the beveled 
tip of the needle assembly. Thereafter, the needle assembly is adapted to 
be employed substantially in the manner described above, although it is 
recognized that the advantages obtained by the locking means of the needle 
assembly 10 of the present invention may be lacking. 
Thus, the apparatus of the present invention described herein provides a 
means by which conventional needle assemblies can be adapted to obtain 
many of the manipulative advantages afforded by the preferred embodiment. 
Of course, although the needle assembly of the present invention is 
described in reference to its applicability to techniques such as 
chemonucleolysis, it is believed that the needle assembly will provide 
great advantage in a wide variety of medical procedures wherein the 
precise placement of needle tips and/or controlled delivery of fluids into 
bodily tissues is desirable. Therefore, the needle assembly of the present 
invention provides a markedly-improved device which can be accurately 
manipulated and maneuvered through bodily tissues to deliver fluids into 
such tissues with a precision and ease of manipulation heretofore not 
known in the art. 
Although the invention has been herein shown and described in what are 
conceived to be the most practical and preferred embodiments, it is 
recognized that departures may be made therefrom within the scope of the 
invention, which is not to be limited to the illustrative details 
disclosed.