Surgical attachment instrument and method

[0001] The present invention relates generally to surgical instruments and in particular to surgical instruments for dissecting bone and other tissue.

[0002] During various surgical procedures, it is necessary to dissect bone or other tissue. Many conventional surgical instruments used for the dissection of bone or other tissue employ pneumatic or electrical motors to rotate a cutting element. In their most basic form, such surgical instruments typically include a motor having a rotary shaft, a dissection tool having a cutting or abrading element that is moved by the rotating shaft of the motor, and a coupling arrangement for connecting the dissection tool to the rotary shaft. The dissection tool often has a small shaft diameter in relation to its length. The shaft may bend or flail in use if not adequately supported or protected. The risk of bending is heightened when the shaft is used with a motor that is designed to reach speeds in excess of 72,000 rpm.

[0003] To support and/or protect a dissection-tool shaft, an attachment or tube may be provided that engages the motor and receives a portion of the dissection-tool shaft. Some attachments or tubes may remain stationary relative to the motor. An example of a stationary attachment is disclosed in detail in co-pending patent application Ser. No. 10/200,683, filed Jul. 22, 2002, the disclosure of which is incorporated by reference.

[0004] Other attachments or tubes may move axially or telescope relative to the motor, thereby allowing the surgeon to vary the distance that the distal end of the tube extends from the motor, and hence vary the distance that the distal end of the dissection-tool shaft extends from the distal end of the tube. Thus, the portion of the dissection-tool shaft received and supported and/or protected by the tube may be varied as desired or needed. For example, a decrease in the portion of the dissecting-tool shaft received by the tube may be required to accommodate spatial constraints associated with the surgical area. An example of a telescoping attachment is disclosed in detail in co-pending patent application Ser. No. 10/326,178, filed Dec. 20, 2002, the disclosure of which is incorporated by reference.

[0005] However, problems may arise during the operation of a surgical instrument having a typical attachment or tube. For example, the stiffness of the tube may not be sufficient to provide adequate stability to the cutting or abrading element, especially in light of the dissection-tool shaft being subjected to various static and/or dynamic loads during normal dissection operation. Also, due in part to vibration, any threadably engaged components of the attachment may disengage from each other during normal dissection operation.

[0006] In addition to the foregoing, for telescoping attachments, many configurations require one or more components to be added to the attachment to provide the telescoping functionality. These components may interfere with the surgeon's line of sight to the surgical area during the dissection operation. Also, it may be difficult for the surgeon to telescope the attachment in an incremental and repeatable manner.

[0007] Therefore, what is needed is a surgical attachment instrument that overcomes one or more of the above-described problems.

[0008]

TABLE 1
United States Patent	Publication		application
Publication No.	Date	Inventor	Ser. No.
2002/0151902	Feb. 17, 2002	Riedel et al.	10/102,762
2002/0165549	Nov. 7, 2002	Owusu-Akyaw et al.	10/135,608
2003/0023256	Jan. 30, 2003	Estes et al.	10/200,683
2003/0163134	Aug. 28, 2003	Riedel et al.	10/164,867
2003/0229351	Dec. 11, 2003	Tidwell et al.	10/164,880
2004/0122460	Jun. 24, 2004	Shores et al.	10/326,178

[0009] All patent publications listed in Table 1 are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and Claims set forth below, many of the devices and methods disclosed in the patent publications of Table 1 may be modified advantageously by using the teachings of the present invention.

[0010] In one embodiment, a surgical attachment instrument includes a housing adapted to be coupled to a motor. A tubular member is coupled to and extends from the housing at a predetermined distance. The predetermined distance may be adjusted in repeatable increments so that the tubular member telescopes relative to the housing in an incremental and repeatable manner. Further, the tubular member may be locked so that longitudinal movement of the tubular member relative to the housing is prevented. Means for adjusting and locking the tubular member are provided without appreciably increasing the surgical attachment instrument's interference with the surgeon's line of sight to the surgical area.

[0011] Further, a coupling connects the tubular member and the housing, and an arcuate member is concentrically disposed between the coupling and the housing. At least a portion of the arcuate member extends in a channel formed in the housing to resist disengagement of the coupling from the housing during operation of the surgical attachment instrument. Still further, the tubular member extends around at least two adjacent bearing assemblies that support a shaft adapted to be coupled to the motor. A spacer extends between the two adjacent bearing assemblies and is lockingly engaged with the tubular member to stabilize the shaft.

[0012] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It is understood that various embodiments of the present invention may overcome one or more of the above-described problems. It is further understood that the detailed description is intended for the purpose of illustration only and is not intended to limit the scope of the invention.

[0031] Referring to FIG. 1, the reference numeral 10 refers, in general, to a dissection tool assembly used to dissect human bone or other tissue. For example and as shown, the dissection tool assembly 10 may be used during a neurological operation on a human patient A to dissect a portion of the patient's bone or other tissue B in order to provide access to the brain or other neurological structures.

[0032] Referring to FIG. 2, the dissection tool assembly 10 includes a surgical attachment instrument 12 having an attachment housing 14. A pneumatic motor 16 having a distal portion 16a is coupled to a cavity portion 14a formed in the housing 14 so that the distal portion is disposed in the cavity portion. The motor 16 is connected to a hose assembly 18 that supplies pressurized air to the motor and vents low-pressure exhaust air away from the surgical area. The motor 16, the hose assembly 18 and the coupling of the motor 16 to the housing 14 are disclosed in detail in co-pending patent application Ser. No. 10/200,683, filed Jul. 22, 2002, the disclosure of which is incorporated by reference.

[0033] A dissection tool 20 includes a shaft 22 and a surgical element such as a dissection head 24 connected to the distal end of the shaft. The shaft 22 is disposed through the surgical attachment instrument 12, and is inserted in and coupled to the distal portion 16a of the motor 16. This coupling of the shaft 22 to the motor 16 is disclosed in detail in the above-incorporated patent application.

[0034] Referring to FIGS. 3 through 5D, the surgical attachment instrument 12 further includes a coupling 26 having an external threaded portion 26a and a circumferentially-extending channel 26b formed in the coupling adjacent to the threaded portion. A protrusion 26c extends out of the channel 26b. A ring 26d extends around the coupling 26 and is disposed adjacent to the channel 26b. Opposing through-openings 26e and 26f are formed in the channel 26b. A groove 26g is formed in the proximal end portion of the coupling 26 and a pair of markings 26h and 26i are printed or formed near the distal end of the coupling, the marking 26h indicating a “locked” position and the marking 26i indicating an “unlocked” position, as will be further described. A bore 26j longitudinally extends through the coupling 26.

[0035] A tubular member 28 includes a bore 28a and a plurality of grooves 28b formed in the wall of the bore at the proximal end of the tubular member. Transverse index markings 29a through 29e are printed or formed in the tubular member 28. Arrow markings 30a through 30c are also printed or formed in the tubular member 28 perpendicular to and through the index markings 29a through 29e. A plurality of crimps 31a, 31b and 31c are formed in the tubular member 28 so that each crimp includes a protrusion portion extending from the inner wall of the tubular member 28. A plurality of transversely-extending locking channels 32a, 32b, 32c, 32d and 32e are formed in the proximal end portion of the tubular member 28. The longitudinal (or axial) spacing between the channels 32a and 32b, 32b and 32c, 32c and 32d, and 32d and 32e are substantially equal and correspond to the spacing between the index marks 29a and 29b, 29b and 29c, 29c and 29d, and 29d and 29e, respectively.

[0036] As more clearly shown in FIG. 4, locking detents 34a through 34e are formed in the tubular member 28 at the ends of the channels 32a through 32e, respectively. Likewise, positioning detents 36a through 36e are formed in the tubular member 28 at the opposing ends of the channels 32a through 32e, respectively. The depth of each detent 34a through 34e, and each detent 36a through 36e, is greater than the depth of each channel 32a through 32e, respectively. A longitudinally-extending positioning channel 38 is formed in the proximal end portion of the tubular member 28 and extends from the detent 36a to the detent 36e, passing through the detents 36b through 36d. The channel 38 is not continuous, but instead is interrupted by the detents 36a through 36e because the depth of the channel is less than the depth of each detent 36a through 36e.

[0037] The foregoing arrangement of the channels 32a through 32e, the detents 34a through 34e, the detents 36a through 36e and the channel 38 is replicated on the surface of the tubular member 28 opposite the surface shown in FIGS. 3 and 4 so that, if the tubular member 28 shown in FIG. 4 was rotated 180 degrees, the view with respect to these replicated channels and detents would be identical to that of FIG. 4. These replicated channels and detents are referred to by corresponding prime reference numerals (the detents 34a′, 34b′, 34c′, 34d′ and 34e′ are shown in FIG. 5B).

[0038] Bearing assemblies 40a, 40b, 40c and 40d are disposed in the bore 28a of the tubular member 28. Spacers 42a, 42b and 42c are also disposed in the bore 28a so that the spacer 42a is positioned between the bearing assemblies 40a and 40b, the spacer 42b is positioned between the bearing assemblies 40b and 40c, and the spacer 42c is positioned between the bearing assemblies 40c and 40d. Channels 42a′, 42b′ and 42c′ are formed in the spacers 42a, 42b and 42c, respectively. As clearly shown in FIG. 5C, the spacers 42a through 42c are positioned in the bore 28a so that the protrusion portions of the crimps 31a, 31b and 31c extend into the channels 42a′, 42b′ and 42c′, respectively, and lockingly engage the spacers.

[0039] A stop 44 is connected to the distal end of the tubular member 28 and a portion of the stop is positioned in the bore 28a. A plug 46 having a pair of channels 46a and 46b is positioned in the bore 28a near the proximal end of the tubular member 28 so that the channels are associated the grooves 28b. The plug 46 applies a force against the bearing assembly 40a and is positioned in the bore 28a so that, due to the fixed position of the stop 44, clamping forces are applied to the bearing assemblies 40a through 40d and the spacers 42a through 42c. The channels 46a and 46b and the grooves 28b are filled with an adhesive such as epoxy so that the plug 46 is fixed within the bore 28a, thereby maintaining the aforementioned clamping forces. The plug 46, the bearing assemblies 40a through 40d, the spacers 42a through 42c and the stop 44 form a substantially continuous bore 48 (shown in FIG. 5B).

[0040] A bore 50 of varying cross-section extends through the housing 14, from the cavity portion 14a and to the distal end of the housing. Balls 52a and 52b are received by the openings 26e and 26f, respectively. A keeper spring 54 is disposed in the channel 26b of the coupling 26 and in a channel 50a formed in the inner wall of the bore 50, contacting and applying inwardly-directed radial forces on the balls 52a and 52b. An arcuate member 56 partially extends about the proximal end portion of the coupling 26. The arcuate member 56 includes a tab 56a that is disposed in the groove 26g.

[0041] When the dissection tool assembly 10 is in its assembled condition shown in FIGS. 5A through 5D, the coupling 26 is disposed in the bore 50 and is threadably engaged with the housing 14 via the threaded portion 26a so that the distal end of the housing is adjacent to or abuts the ring 26d. The outer surfaces of the housing 14 and the ring 26d are substantially flush. It is understood that an adhesive such as epoxy may be applied to the threaded portion 16a. The tubular member 28 is slidably engaged with the coupling 26 so that the balls 52a and 52b are seated in the opposing detents 34e and 34e′, respectively, and the distal end of the tubular member 28 extends from the housing 14 at a predetermined distance. The outer diameter of the coupling 26 decreases from the ring 26d to the distal end of the coupling so that, at the distal end, the difference between the outer diameters of the coupling and the tubular member 28 is relatively small.

[0042] The shaft 22 of the dissection tool 20 extends through the bore 48 and, as discussed above, is inserted in the distal portion 16a of the motor 16 which, in turn, is positioned within the cavity portion 14a of the housing 14 (motor not shown). The dissection head 24 and the distal portion of the shaft 22 extend out from the tubular member 28. The tubular member 28 is in a “locked” position, as indicated by the alignment of the arrow marking 30c with the marking 26h shown in FIG. 5A, because the tubular member 28 is unable to move relative to the coupling 26, as will be further described in detail below.

[0043] In operation, the motor 16 receives high-pressure air via the hose assembly 18 to rotate a rotor shaft (not shown in the Figures) that is coupled with the shaft 22 of the dissection tool 20, as disclosed in detail in the above-incorporated patent application. Due to this coupling, the shaft 22 rotates, thereby rotating the dissection head 24, which may be applied against bone or other human tissue to cut or dissect the bone or tissue. Low-pressure exhaust air exits the motor 16 through an exhaust passage in the hose assembly 18.

[0044] During this time, the dissection tool assembly 10 is in its assembled condition described above and the shaft 22 rotates in the bores 48 and 50. The bearing assemblies 40a through 40d support the rotating shaft 22. Due to the above-described clamping forces, the spacers 42a, 42b and 42c limit any movement of the bearing assemblies 40a through 40d relative to the bore 28b of the tubular member 28, providing increased stability to the shaft 22.

[0045] The locking engagement of the crimps 31a, 31b and 31c with the channels 42a′, 42b′ and 42c′, respectively, facilitates the binding of the wall of the bore 28b to the spacers 42a, 42b and 42c, respectively, thereby limiting any movement of the spacers relative to the bore 28b. This serves to better stabilize the shaft 22 while the dissection head 24 is dissecting the bone or tissue, during which time the dissection tool assembly 10 is subjected to a variety of static and/or dynamic (shock or vibrating) loads in a variety of directions. The binding of the wall of the bore 28b to the spacers 42a through 42c also increases the stiffness of the tubular member 28, providing increased stability to the shaft 22, especially when the coupling 26 or the tubular member 28 is subjected to static or dynamic transverse loading.

[0046] The adhesive applied to the threaded portion 26a prevents the coupling 26 from disengaging from the housing 14 while the dissection tool assembly 10 is undergoing the above-described static and dynamic loading. The arcuate member 56 secondarily prevents the coupling 26 from disengaging from the housing 14, as will be further described in detail below.

[0047] As noted above and during operation, the tubular member 28 is in a “locked” position where the tubular member 28 is unable to move in a longitudinal direction relative to the coupling 26, the housing 14 and the tool 20. It is understood that a “locked” position during operation of the dissection tool assembly 10 is desirable in order to prevent any unwanted axial movement of the tubular member 28, relative to the coupling 26 and the shaft 22, that might interfere with the surgeon's line of sight or the cutting operation of the dissection head 24, thereby possibly increasing the risk of harm to the human patient.

[0048] As shown in FIGS. 5B and 5D, the tubular member 28 is prevented from moving longitudinally relative to the coupling 26 because the balls 52a and 52b are seated in the detents 34e and 34e′, respectively. If the surgeon attempts to move the tubular member 28 in a direction towards the dissection head 24, the tubular member 28 will remain substantially in position due to the contact between the walls of the detents 34e and 34e′ and the substantially immobile balls 52a and 52b extending through the through-openings 26e and 26f, respectively. It is understood that the tubular member 28 is prevented from moving relative to the coupling 26 when the ball 52a is seated in any one of the detents 34a through 34e, and the ball 52b is seated in any one of the detents 34a′ through 34e′.

[0049] The keeper spring 54 prevents the balls 52a and 52b from falling out of the through-openings 26e and 26f, respectively. The keeper spring 54 holds the balls 52a and 52b in place due to the spring's application of inwardly-directed radial forces on the balls. The protrusion 26c limits the rotation of the keeper spring 54 about the coupling 26 in the channel 26b to the extent that the location of the split in the keeper spring 54 does not correspond to the location of the through-openings 26e and 26f (split shown in FIG. 3).

[0050] As shown in FIGS. 5A and 5B, the distal portion of the shaft 22 is exposed to view, extending out from the tubular member 28 as far as possible while remaining in a “locked” position as described above. The alignment of the distal end of the coupling 26 with the index marking 29e further indicates this condition of maximum shaft 22 extension and the corresponding maximum insertion of the tubular member 28 into the coupling 26. In order for the tubular member 28 to protect and/or support a greater amount of the distal portion of the shaft 22, the tubular member is moved axially in a direction towards the dissection head 24, relative to the coupling 26, the housing 14 and the tool 20.

[0051] To so move the tubular member 28, the motor 16 is adjusted so that the shaft 22 of the tool 20 ceases to rotate. The tubular member 28 is then rotated counterclockwise (as viewed in FIGS. 3 and 4) about its longitudinal axis while the coupling 26 remains stationary. Rotation of the tubular member 28 results in the rotation of the channel 32e (FIG. 5D) towards the ball 52a. The difference between the depths of the detent 34e and the channel 32e is sized so that the channel 32e is able to slide underneath the ball 52a. The keeper spring 54 resists the sliding of the channel 32e and the corresponding outwardly-directed radial movement of the ball 52a, providing tactile and/or acoustic feedback to the surgeon that indicates that the channel is indeed underneath the ball 52a. It is understood that the operation of the tubular member 28 with respect to the ball 52b, and the corresponding channels and detents referred to by prime reference numerals, is identical to the foregoing, and is also identical to the below-described operation with respect to the ball 52a, and therefore will not be described.

[0052] Referring to FIGS. 6A through 6C, rotation of the tubular member 28 is continued so that the channel 32e continues to slide against the ball 52a until the ball 52a falls into the detent 36e, assisted by the force applied on the ball by the keeper spring 54. The falling of the ball 52a from the channel 32e and into the detent 36e, and the corresponding decrease in loading on the keeper spring 54, provides both acoustic and tactile feedback to the surgeon, indicating that the ball is indeed in the detent 36e and in an “unlocked” position. The alignment of the arrow 30c with the marking 26i provides further confirmation of this “unlocked” position. The contact between the ball 52a and the wall of the detent 36e prevents the tubular member 28 from further counterclockwise rotation.

[0053] A longitudinally-directed force is applied to the tubular member 28 so that the tubular member is moved axially in the direction towards the dissection head 24, during which time the channel 38 slides along underneath the ball 52a. As the detents 34d, 34c and 34b also slide underneath the ball 52a during this movement, the ball drops down into each detent, providing acoustic and tactile feedback to the surgeon as to the extent of the tubular member 28's movement. The movement of the index markings 29a through 29e relative to the coupling 26 further indicates the extent of the tubular member 28's movement. The tubular member 28 continues to be moved axially until the detent 36a slides underneath the ball 52a and the ball drops into the detent. Contact between the ball 52a and the wall of the detent 36a prevents further axial movement of the tubular member 28 in the direction towards the dissection head 24.

[0054] The tubular member 28 is placed in a “locked” position by rotating the tubular member 28 in a clockwise direction (as viewed in FIGS. 3 and 4). During this rotation and referring to FIGS. 7A through 7C, the detent 34a rotates towards the ball 52a while the channel 32a slides underneath the ball. The ball 52a falls into the detent 34a, providing acoustic and tactile feedback to the surgeon, indicating that the ball is indeed in the detent 34a and in a “locked” position. At this point, the tubular member 28 protects and/or supports the greatest amount of the distal portion of the shaft 22 while still being in a “locked” position, as indicated by the alignment of the distal end of the coupling 26 with the index marking 29a, and the alignment of the arrow 30a with the marking 26h. Normal operation of the motor 16, and the corresponding rotation of the shaft 22 and the dissection head 24, may now resume.

[0055] Instead of axially moving the tubular member 28 until the ball 52a falls into the detent 36a, it is understood that the movement of the tubular member 28 may be stopped at any point along the channel 38. If the tubular member 28 movement is stopped when the ball 52a is located in the detents 36b, 36c and 36d, the acoustic and tactile feedback of the ball 52a falling into any one of these detents indicates to the surgeon that the tubular member 28 may be locked with respect to its current position relative to the coupling 26 and the shaft 22. The alignment of one of the index markings 29a through 29e with the distal end of the coupling 26 further indicates to the surgeon that the tubular member 28 may be placed in a “locked” position. Regardless of which detent 36a through 36e the ball 52a is seated in, the procedure for locking the tubular member 28 is identical to the above-described procedure. Further, rotation of the shaft 22 and the dissection head 24 may safely resume as long as the tubular member 28 is locked, that is, the ball 52a is seated in one of the detents 34a through 34e.

[0056] It is understood that the tubular member 28 may be unlocked in the above-described manner, moved axially in either direction with respect to the coupling 26, and then locked in the above-described manner. Thus, the tubular member 28 may be selectively adjusted so that it telescopes in and out of the coupling 26, towards and away from the dissection head 24 in discrete, repeatable, and indexed increments. Further, this selective adjustment may be carried out without an appreciable increase in the surgical attachment instrument 12's interference with the surgeon's line of sight to the surgical area. This lack of interference is due in part to the outer surfaces of the housing 14 and the ring 26d being substantially flush, and the decrease in the outer diameter of the coupling 26 from the ring to the distal end of the coupling. This lack of interference is further due in part to the positioning of the balls 52a and 52b and the keeper spring 54 within the housing 14.

[0057] As noted above, the arcuate member 56 prevents the threaded portion 26a of the coupling 26 from disengaging from the housing 14. Referring to FIGS. 8A through 9B, with continuing reference to FIG. 3, a recess 58 having walls 58a and 58b is formed in the wall of the bore 50, and a recess 60 is formed in a wall 58b of the recess 58. The recess 60 includes two walls 60a and 60b and a channel 62 is formed in the wall 60b. When the dissection tool assembly 10 is in its assembled condition, the edge of the arcuate member 56 opposing the tab 56a is contacting the wall 60a. A portion of the arcuate member 56 is crumpled and extends into the channel 62 formed in the wall 60b (most clearly shown in FIG. 9B). It is understood that the material of the arcuate member 56 is softer than the material of the coupling 26 and the housing 14.

[0058] In operation, the arcuate member 56 initially has an L-shaped cross-section, before the coupling 26 is fully engaged with the housing 14, as shown in FIG. 9A. During assembly, as the coupling 26 is threadably engaged with the housing 14 via the threaded portion 26a, the proximal end of the coupling 26 moves axially towards the wall 58a and the arcuate member 56 moves towards and engages the wall 60a. The threaded engagement of the coupling 26 with the housing 14 is continued so that the proximal end of the coupling 26 continues to move towards the wall 58a. Due to the interfering engagement between the arcuate member 56 and the wall 60a, a portion of the arcuate member crumples and is forced upwards into the channel 62, as shown in FIG. 9B. During the normal operation of the dissection tool assembly 10, the threaded portion 26a of the coupling 26 is prevented from disengaging from the housing 14 due in part to the contact between the crumpled portion of the arcuate member 56 and the walls of the channel 62.

[0059] During disassembly, a predetermined amount of torque applied to the coupling 26 will either break or severely damage the arcuate member 56 so that the coupling may be disengaged from the housing 14. The partial circumferential extension of the arcuate member 56 enables the arcuate member to be easily removed from the coupling 26 and/or the channel 62. The broken or damaged arcuate member 56 may be discarded and a new arcuate member may be used when re-assembling the coupling 26 and the housing 14.

[0060] It is understood that variations may be made in the foregoing without departing from the scope of the disclosure. These variations include the following:

[0061] 1. The ball 52b may be removed from the dissection tool assembly 10, along with the corresponding channels 32a′ through 32e′ and 38′, and the detents 34a′ through 34e′ and 36a′ through 36e′.

[0062] 2. The number of balls may be increased to three or more, along with a corresponding increase in the channels and detents formed in the tubular member 28.

[0063] 3. The spacers 42a through 42c may be in the form of resilient components such as elastomer or helical springs. For such embodiments, it is understood that the crimps 31a through 31c and the corresponding channels 42a′ through 42c′ may be removed.

[0064] 4. The position of the plug 46 in the bore 28a may be varied.

[0065] 5. Instead of using an adhesive in conjunction with the channels 46a and 46b and the grooves 28b, the plug 46 may be connected to the tubular member 28 by other means such as, for example, with fasteners.

[0066] 6. In addition to the pneumatic motor 16, other types of motors using electricity or other motive forces may be used with the dissection tool assembly 10. It is understood that, if other types of motors are employed, the hose assembly 18 may be removed from the dissection tool assembly 10.

[0067] 7. In addition to the dissection head 24, other types of dissection heads may be connected to the distal end of the shaft 22. Further, in addition to dissection heads, other types of surgical elements may be connected to the distal end of the shaft 22 such as, for example, polishing elements.

[0068] 8. The number of bearing assemblies and spacers in the tubular member 28 may be varied.

[0069] 9. The design of the keeper spring 54 may be modified so that there is one keeper spring engaging each ball 52a and 52b. Also, the keeper spring 54 may be in the form of other types of resilient members such as, for example, a helical spring.

[0070] 10. Any foregoing spatial references, such as “upper,” “between,” “front,” “right side,” “side,” “above,” “beneath,” etc., are for the purpose of illustration only and do not limit the specific spatial orientation of the structure described above.

[0071] The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, therefore, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the invention or the scope of the appended claims. For example, the present invention is not limited to instruments and methods for telescoping an attachment tube, stabilizing a rotating shaft in connection with a dissection tool assembly, or connecting different components of a dissection tool assembly. The present invention is also not limited to instruments and associated methods for dissecting bone or other tissue per se, but may find further application in other operations such as, for example, dental procedures. The present invention further includes within its scope the methods of making, assembling and using the dissection tool assembly 10 described hereinabove.

[0072] It is intended that the scope of the disclosure be defined by the claims appended hereto and their equivalents. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts a nail and a screw are equivalent structures.