Surgical instrument for setting large diameter burr holes

Abstract

A device and method for eliminating subdural hematomas with a reduced recurrence rate, avoiding the use of general anesthesia and allowing treatment with reduced risk to those affected. The device includes a precision cutting tool used to create a uniform diameter within an existing hole in a target area of ​​a subject, thereby maximizing the diameter-to-depth ratio of the hole and simultaneously removing material in both radial and axial directions. The method includes establishing an initial hole to facilitate placement of a port within an implant hole in the target area of ​​a subject.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This non-provisional application claims priority to U.S. Provisional Patent Application No. 63 / 478,779, entitled "SYSTEMS AND DEVICES FOR LARGE BURR HOLE INTRACRANIAL ACCESS AND EVACUATION," filed January 6, 2023, by the same inventors.

[0002] The present invention relates generally to systems, devices, and methods for providing intracranial access, and more particularly to devices and methods for creating large diameter burr holes having a constant diameter throughout to enable placement of large diameter ports and improve surgical outcomes. [Background technology]

[0003] Chronic subdural hematoma (CSDH) is a debilitating condition that affects a significant proportion of the population, particularly middle-aged and older adults, both in the United States and worldwide. CSDH involves the collection of blood between the arachnoid and dura mater layers on the brain surface and can occur due to rupture of venous, arterial, and capillary networks. This rupture can be caused by traumatic events and the use of antiplatelet and anticoagulant medications. CSDH can also cause weakness, speech impairment, seizures, impaired consciousness, and death. While the current global annual incidence of CSDH ranges from 1 to 5 cases per 100,000 people, CSDH disproportionately affects middle-aged and older adults, with annual incidence rates as high as 58 cases per 100,000 people in those over 70 years of age. Furthermore, intracranial hematoma (IPH) is the most common form of hemorrhagic stroke, occurring at a rate of 24.6 per 100,000 people per year. By 2030, it is estimated that 19% of the U.S. population will be over 65 years of age, increasing the projected number of people affected by CSDH. Between 1998 and 2007, the annual hospitalization rate for treatment of inpatient subdural hematomas increased from 39 per 100,000 (per capita) to 41.6 per 100,000 (per capita), with the current estimated cost of such hospitalizations being $1.6 billion annually. CSDH is projected to become the most common condition requiring neurosurgical intervention by 2030.

[0004] Subdural hematomas are typically treated by creating a burr hole in the patient's head and attaching a port to the patient's skull. However, these ports often have a small internal lumen, e.g., 5 mm or less. These smaller lumens are prone to clogging, and the small diameter of the internal lumen typically results in an inability to completely remove the hematoma. Therefore, the recurrence rate of CSDH can be as high as approximately 28%.

[0005] Until the present invention, it seemed impossible to secure larger ports in the minimal bone thickness available within the skull due to the lack of precision of the burr holes, and although attempts were made, larger ports did not have good pull-out strength, leading to unintentional port removal.

[0006] Therefore, there is a need for a surgical instrument that allows for the setting of large diameter burr holes and the placement of large diameter ports to improve the outcome of surgical procedures. However, in light of a general review of the state of the art at the time the present invention was made, it was not obvious to one skilled in the art how the shortcomings of the prior art could be overcome.

[0007] All referenced publications are incorporated herein by reference in their entirety. Furthermore, to the extent that the definition or usage of a term in a reference incorporated herein by reference is inconsistent with or contradicts the definition of that term set forth herein, the definition of that term set forth herein shall apply and the definition of that term in the reference shall not apply.

[0008] Although certain aspects of the prior art have been discussed to facilitate disclosure of the present invention, the applicant does not in any way deny these technical aspects, and it is envisioned that the claimed invention may include one or more of the aspects of the prior art discussed herein.

[0009] The present invention may address one or more of the problems and deficiencies of the prior art discussed above. However, it is contemplated that the present invention may prove useful in addressing other problems and deficiencies in some technical areas. Accordingly, the claimed invention should not necessarily be construed as limited to addressing any of the specific problems or deficiencies discussed herein.

[0010] Where a document, statute, or article of knowledge is referenced or discussed in this specification, such reference or discussion does not constitute an admission that the document, statute, or article of knowledge, or any combination of the foregoing, was publicly available, known to the public, part of the common general knowledge, or otherwise constitutes prior art under applicable provisions of law or was known to be relevant to any attempt to solve any problem(s) involved in this specification, as of the priority date. Summary of the Invention

[0011] The long-existing but heretofore unmet need for surgical instruments and methods for creating large diameter burr holes, enabling the placement of large diameter ports, and improving the outcomes of surgical procedures is now met by a new, useful, and non-obvious invention.

[0012] The present invention includes devices and methods for creating large diameter burr holes to enable placement of large diameter ports within a patient. In some embodiments, the device includes a precision cutting tool having a distal end and an opposing proximal end, with a body extending between the proximal and distal ends. The proximal end is fixed or attachable to a rotatable coupling on the drill face, while the cutting structure is adjacent the distal end.

[0013] The cutting structure includes a plurality of radial cutting edges and a plurality of nose cutting edges. Each of the plurality of radial cutting edges extends radially outward, and each of the plurality of nose cutting edges extends distally outward at a distal end of the precision cutting tool. In some embodiments, the plurality of radial cutting edges includes five or more radial cutting edges and / or the plurality of nose cutting edges includes five or more nose cutting edges. The precision cutting tool may further include a plurality of helical flutes, each of the plurality of helical flutes coupled to one of the plurality of radial cutting edges and / or one of the plurality of nose cutting edges.

[0014] In some embodiments, each of the radial cutting edges of the precision cutting tool includes a rake angle of about -20° to about 20°, at least one diametric secondary rake angle of about 3° to about 30°, and / or a phase width face having an arc length of about 0.1 mm to about 0.6 mm. Additionally, each of the nose cutting edges of the precision cutting tool includes a rake angle of about -20° to about 20°, at least one clearance face having a clearance angle of about 3° to about 30°, and at least one clearance face having a clearance angle of about 3° to about 30°.

[0015] The cutting structure may further include a central recessed area disposed at the distal end of the surgical instrument and / or have an outer diameter of about 7 mm or greater.

[0016] Some embodiments of the precision cutting tool include a safety stop a predetermined distance from the distal end of the precision cutting tool, which may be at the distal end of the removable cover when the removable cover is operably engaged with the surgical instrument.

[0017] The present invention may further include a method for creating a large-diameter burr hole to enable placement of a large-diameter port within a patient. The method includes setting an initial hole to create an implantation hole. The step of setting the initial hole includes rotating a precision cutting tool within the initial hole. The precision cutting tool includes a cutting structure having a plurality of radial cutting edges extending radially outward, each of the plurality of radial cutting edges coupled to one of a plurality of helical flutes extending along the body of the precision cutting tool. The cutting structure also includes a plurality of nose cutting blades extending distally outward at a distal end of the precision cutting tool, each of the plurality of nose cutting blades coupled to one of the plurality of helical flutes. The plurality of radial cutting edges and the plurality of nose cutting blades are configured to remove a volume of material from a bone of a subject to create the implantation hole.

[0018] These and other important objects, advantages and features of the present invention will become apparent as the disclosure proceeds.

[0019] The invention accordingly comprises the features of construction, combination of elements and arrangement of parts exemplified in the disclosure which follows, the scope of the invention being indicated in the appended claims.

[0020] For a more complete understanding of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view of a precision cutting tool according to one embodiment of the present invention; [Figure 2] FIG. 1 is a perspective view of one embodiment of a precision cutting tool with the cover removed. [Figure 3] 1 is a cross-sectional view of one embodiment of a precision cutting tool. [Figure 4] FIG. 1 is a cross-sectional enlarged side view of the distal end of one embodiment of a precision cutting tool. [Figure 5] FIG. 1 is an end view of the distal end of one embodiment of a precision cutting tool. [Figure 6] FIG. 1 is a perspective end view of the distal end of one embodiment of a precision cutting tool. [Figure 7] FIG. 1 is a cross-sectional view of a distal end of one embodiment of a precision cutting tool. [Figure 8] FIG. 1 is a cross-sectional view of a nose cutting edge of one embodiment of a precision cutting tool. DETAILED DESCRIPTION OF THE INVENTION

[0022] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

[0023] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification and the appended claims, the word "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0024] All numerical designations, such as measurements, efficiencies, physical properties, forces, and other designations, including ranges, are approximations that are varied by increments of 1.0 or 0.1 as appropriate. It should be understood, even if not always explicitly stated, that all numerical designations are preceded by the word "about" or "approximately." As used herein, "approximately" or "about" refers to being within an acceptable error range for a particular value as determined by one of ordinary skill in the art, which range will depend in part on how the value is measured or determined. For example, the word "about" can refer to ±10% of the numerical value.

[0025] As used herein, "subject" or "patient" is used to describe a human or other animal to which treatment is administered.

[0026] As used herein, "target area" is used to describe an area of ​​a subject requiring medical attention, such as the skull of a subject experiencing symptoms due to a subdural hematoma.

[0027] The present invention includes surgical instruments and methods for creating large burr holes in a patient using the instruments. In some cases, the created burr holes allow for non-surgical (e.g., bedside) evacuation of subdural hematomas with reduced recurrence rates, avoiding the use of general anesthesia and allowing treatment with reduced risk to those affected. The improved surgical instruments and methods of use are described in more detail below. Although the present invention is described herein with respect to cranial procedures, the system, its components, and methods of use can be used for other anatomical locations on a patient and / or for performing other procedures, including non-surgical procedures.

[0028] As explained above, placing a port in an implantation hole larger than 5 mm was prone to error, making it impossible for the port to securely remain in the bone. One contributing factor to this problem was the skull's minimal thickness, ranging from about 4.7 mm to about 14.7 mm, with an average thickness of about 8.6 mm. It was determined that this minimal thickness required an extremely precise hole to securely implant the port within the skull. More specifically, the implantation hole required a previously unachieved level of precision with respect to perpendicular orientation to the implantation site, interior wall configuration, and uniform internal diameter. Accordingly, the present invention includes a precision cutting tool designed to achieve these requirements.

[0029] Referring now to the figures, one embodiment of the present invention includes a precision cutting tool 100. In some embodiments, the precision cutting tool 100 is configured to set an initial hole created by an initial cutting tool, thereby creating an implantation hole.

[0030] The precision cutting tool 100 is made of a material that is hard enough to cut bone and tissue, hi some embodiments, the precision cutting tool 100 is made from a hard metal such as stainless steel, carbon steel, titanium, tungsten carbon, combinations thereof, or similar materials of similar hardness.

[0031] 1-3, precision cutting tool 100 includes a proximal end 102, a distal cutting end 104, and a body portion 106 extending therebetween. Proximal end 102 may be configured to be received by a coupling receptacle of a drill or may be permanently secured to a rotating element of the drill. When configured to be received by a coupling receptacle of a drill, proximal end 102 is designed with a coupling 108, such as the depicted Hudson coupling, that is selectively receivable and securable within the coupling receptacle of the drill.

[0032] Some embodiments include a cover 110 that at least partially surrounds the precision cutting tool 100. The cover 110 has a length shorter than the length of the precision cutting tool 100 so that the proximal end 102 can be received by a coupling receiver of a drill, while a portion 112 of the distal cutting end 104 remains exposed to engage and cut bone. The distal-most end 114 of the cover 110 acts as a safety stop to prevent further penetration of the precision cutting tool 100 beyond the length of the exposed distal end 112. Alternatively, some embodiments rely on a ledge disposed between the proximal and distal ends 102, 104 of the precision cutting tool 100 to function as a safety stop. In another embodiment, an annulus is disposed between the proximal and distal ends 102, 104 of the precision cutting tool 100. It should be appreciated that any stop element, such as a terminal edge, shelf, annulus, and similar mechanical element, can be used in combination with the precision cutting tool 100 so long as the stop element has a diameter larger than the diameter of the exposed portion 112 of the precision cutting tool 100.

[0033] Additionally, the cover 110 can be attached to the precision cutting tool 100 in such a way that it can spin independently of the precision cutting tool 100. As a result, the cover 110 can remain stationary while the precision cutting tool 100 rotates, thereby preventing damage to the patient's skin and hair during use.

[0034] In one embodiment, exposed portion 112 is approximately 5 mm in length, requiring the target area (such as the skull) to be at least 6 mm thick to avoid complete penetration of the inner cranium, although it should be appreciated that varying lengths of exposed portion 112 may be used depending on the thickness of the bone. For example, in one embodiment, sufficient engagement can be achieved with a depth of approximately 2 mm, and thus, in one embodiment, exposed portion 112 is approximately 2 mm in length. Other lengths of exposed portion 112, including 3 mm, 3.5 mm, 4 mm, and 4.5 mm, are contemplated herein for achieving sufficient engagement with the target area of ​​the subject. In some embodiments, exposed portion 112 is approximately 2 mm to 6 mm in length. In some embodiments, exposed portion 112 is approximately 2 mm to 14 mm in length.

[0035] To achieve alternative lengths for the exposed portion 112, some embodiments include multiple covers having different lengths. Additionally, one or more of the covers 110 may be detachable, as best depicted in FIG. 2 . In such embodiments, the cover 110 includes one or more sections that are detachable from one another via mechanical, magnetic, or other attachment mechanisms. The depicted embodiment of the cover 110 includes two sides, with the first side 116 having one or more receptacles 118 dimensioned to receive cantilever snaps 120 on the second side 122. The cantilever snaps 120 can flex with force into and out of the receptacles 118. Again, alternative mechanisms can be employed to secure the one or more sections of the cover 110 around the body portion 106.

[0036] As best depicted in FIG. 3 , one or more covers 110 include one or more inwardly extending protrusions 124. The body portion 106 of the precision cutting tool 100 includes a protrusion receiver 126 configured to receive the protrusions 124 and help hold the cover 110 in position relative to the distal cutting end 104 of the precision cutting tool 100. The depicted receiver 126 is in the form of an annular groove to receive the annular protrusion 124. However, alternative retention structures are contemplated, including, but not limited to, separate semicircular protrusions and receivers.

[0037] Some embodiments of the precision cutting tool 100 include a shoulder 127 configured to contact the proximal end of the cover 110, thereby preventing proximal translation of the cover 110 relative to the body portion 106. Similar to the projection receiving portion 126, the shoulder 127 ensures that the cover 110 provides the necessary safety stop during use.

[0038] 4-8 , the exposed portion 112 (also referred to as the "cutting structure") of the precision cutting tool 100 includes a plurality of radial cutting edges 130 and a plurality of helical flutes 128 adjacent the distal end 104 of the precision cutting tool 100 such that the plurality of radial cutting edges 130 are configured to interact with the interior sidewalls defining the initial hole when inserted into the initial hole. The radial cutting edges 130 are oriented generally parallel to the central axis of rotation of the precision cutting tool 100. Thus, when inserted into the initial hole, the radial cutting edges 130 remove material from the sidewalls of the initial hole as the precision cutting tool 100 rotates.

[0039] Rather than using spiral flutes that are substantially parallel to the interior sidewalls that define the initial hole or that are substantially perpendicular to the interior sidewalls that define the initial hole, the plurality of spiral flutes 128 of the precision cutting tool 100 extend in a generally spiral pattern around at least the outer periphery of the cutting structure of the precision cutting tool 100. The radial cutting edges 130 and spiral flutes 128 are such that the precision cutting tool 100 is configured to remove a minimal amount of material radially within the initial hole, with the spiral flutes 128 and radial cutting edges 130 functioning similar to a reaming tool to set the diameter of the hole to a very precise and uniform diameter.

[0040] As best depicted in FIG. 7 , the plurality of radial cutting edges 130 include a rake angle γ of approximately 2°, although the rake angle γ can be approximately -20° to 20°. To ensure that the radial cutting edges 130 are strong enough to create minimal debris during cutting, the plurality of radial cutting edges 130 also include one or more flanks 132 on the bar surface trailing each of the cutting edges 130. Some embodiments include a phase width surface 132a and a secondary flank surface 132b in different planes as depicted. The phase width surface 132a is depicted as having an arc length Δ of approximately 0.24 mm, and the secondary flank surface 132b is depicted as having a secondary rake angle relative to the diameter α of approximately 24°, although the phase width can have an arc length of approximately 0.1 mm to 0.6 mm, and the secondary rake angle relative to the diameter can be approximately 3° to 30°.

[0041] The combination of the rake and / or clearance angles ensures that the multiple radial cutting edges 130 precisely set the initial hole and minimize the increase in diameter of the initial hole by removing a minimal amount of material. Additionally, these characteristics allow the multiple radial cutting edges 130 to create a substantially uniform diameter from the insertion end of the initial hole to the termination end of the initial hole.

[0042] To establish a uniform diameter, the cutting structure has an outer diameter established by the radial cutting edges 130. The outer diameter of the cutting structure is larger than the outer diameter of the initial cutting tool and / or initial hole. In some embodiments, the outer diameter of the cutting structure is between about 7 mm and 16 mm. In some embodiments, the outer diameter of the cutting structure is at least 7 mm. In some embodiments, the outer diameter of the cutting structure is roughly 14 mm.

[0043] The larger the outer diameter disclosed above relative to the cutting depth (i.e., the length of the cutting structure from the safety stop to the distal tip), the greater the diameter-to-depth ratio, where the diameter is equal to or greater than the length of the cutting structure from the safety stop to the distal tip. For example, if the length of the cutting structure from the safety stop to the distal tip is 3 mm, non-limiting examples of diameter-to-depth ratios include 6:3, 7:3, 14:3, 15:3, and even 20:3. As another example, if the length of the cutting structure from the safety stop to the distal tip is 5 mm, the diameter-to-depth ratio can be 6:5, 7:5, 14:5, 15:5, and even 20:5.

[0044] The cutting structure of the precision cutting tool 100 also includes a plurality of nose cutting edges 134 disposed at the distal end 104 of the precision cutting tool 100 such that each of the plurality of spiral flutes 128 terminates in a respective individual nose cutting edge 134. As best depicted in FIG. 7 , each of the plurality of nose cutting edges 134 includes a rake angle β and a clearance / play angle θ to create a cutting surface similar to an end mill tool. In one embodiment, these angles of the plurality of nose cutting edges 134 are greater than the angles of the helical orientation of the plurality of spiral flutes 128, although it should be recognized that varying the angles between the plurality of nose cutting edges 134 and the plurality of spiral flutes 128 is contemplated herein, so long as sufficient depth in the initial hole is achieved when modified by the precision cutting tool 100. 7, the rake angle β of the plurality of nose cutting edges 134 is approximately -9°, and the clearance angle θ1 and play angle θ2 of the plurality of nose cutting edges 134 are approximately 5° and 10°, respectively. In one embodiment, the rake angle β of the plurality of nose cutting edges 134 is approximately -20° to 20°, and the clearance angle θ1 and play angle θ2 of the plurality of nose cutting edges 134 are approximately 3° to 45°.

[0045] To ensure that the nose cutting edge 134 is strong enough to create minimal debris during cutting, one or more flanks are provided on the bar surface trailing the cutting edge 134. Some embodiments include at least one flank 136a and at least one clearance surface 136b in different planes, with corresponding clearance angles θ1 between about 3° and 30°, and clearance angles θ2 between about 3° and 30°. Some embodiments include three or more flanks in different planes.

[0046] The rake and clearance / play angles of the nose cutting edges 134 together create a cutting surface that is dedicated to removing material axially toward the end of the initial hole, such as the subject's skull surface. Together, the radial cutting edges 130 and nose cutting edges 134 remove minimal material radially and axially to precisely set the diameter and depth of the initial hole for receiving and securing a port within the initial hole. As a result, the initial hole is modified into an implantation hole that provides intracranial access with sufficient depth to ensure that a port inserted into the implantation hole will not be unintentionally dislodged, for example. Furthermore, the spiral nature of the spiral flutes 128 is such that material removed by the radial cutting edges 130 and nose cutting edges 134 is removed from the implantation hole, and the removed material is pushed out from the end as more material is removed and moves through the spiral of the spiral flutes 128.

[0047] The distal end 104 of the precision cutting tool 100 further includes a central recessed area 138 relative to the distal protrusion of the nose cutting edge 134. The recessed area 138 is countersunk so that the distal end 104 has sufficient space to receive bone fragments as they are cut from the hole and is also less likely to sink into the patient's tissue.

[0048] 5-7, the precision cutting tool 100 includes nine nose cutting edges 134 and nine radial cutting edges 130 that result in nine helical flutes 128 to create a precise embedment hole. Some embodiments may have five or more nose cutting edges 134 and five or more radial cutting edges 130 that result in five or more corresponding helical flutes 128 to achieve an embedment hole precise enough to securely receive a port. In some embodiments, the number of helical flutes 128 corresponds to the number of nose cutting edges 134 and / or the number of radial cutting edges 130.

[0049] The present invention further includes a method for setting a large diameter burr hole in a patient. The method includes setting a pilot hole in the patient at a target location, such as the patient's head, to an implantation hole having a precise diameter. The step of setting the pilot hole includes rotating a precision cutting tool within the pilot hole. The precision cutting tool may be designed according to the precision cutting tool 100 described herein.

[0050] The advantages set forth above and those made apparent from the preceding description are effectively attained. Since several changes can be made in the above-described constructions without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

[0051] It should also be understood that the following claims are intended to cover all of the general and specific features of the invention described herein, as well as all statements of the scope of the invention that may be said to fall between the two as a matter of language.

Claims

1. 1. A surgical instrument for creating a large diameter burr hole in a patient, comprising: a proximal end opposite the distal end, with a body extending between the proximal end and the distal end; adjacent the distal end; a plurality of radial cutting edges each extending radially outward; a plurality of nose cutting edges each extending distally outward at the distal end of the surgical instrument; Including, The outer diameter is approximately 7 mm or more. Cutting structure and A surgical instrument comprising:

2. The surgical instrument of claim 1 , further comprising a central recessed area disposed at the distal end of the surgical instrument.

3. The surgical instrument of claim 1 , wherein the plurality of radial cutting edges comprises five or more radial cutting edges.

4. The surgical instrument of claim 1 , wherein the plurality of nose cutting edges comprises five or more nose cutting edges.

5. The surgical instrument of claim 1 , further comprising a plurality of helical flutes, each coupled to one of the plurality of radial cutting edges.

6. The surgical instrument of claim 1 , further comprising a plurality of spiral flutes each connected to one of the plurality of nose cutting edges.

7. The surgical instrument of claim 1 , wherein each of the radial cutting edges includes a rake angle of from about −20° to about 20°.

8. The surgical instrument of claim 1 , wherein each of the radial cutting edges includes a clearance angle of from about 3° to about 30°.

9. The surgical instrument of claim 1 , wherein each of the nose cutting edges includes a rake angle of from about −20° to about 20°.

10. The surgical instrument of claim 1 , wherein each of the nose cutting edges includes at least one clearance surface having a clearance angle of from about 3° to about 45°.

11. 10. The precision cutting tool of claim 1, further comprising a safety stop at a predetermined location from the distal end of the precision cutting tool, thereby establishing a maximum penetration depth of the precision cutting tool.

12. The surgical instrument of claim 11 , wherein the safety stop is a distal end of the removable cover when the removable cover is fixedly attached to the surgical instrument.

13. The surgical instrument of claim 1 , wherein the proximal end is fixed to or attachable to a rotatable connection on a drill surface.

14. 1. A precision cutting tool for creating a large diameter burr hole in a patient, comprising: a proximal end opposite the distal end, with a body extending between the proximal end and the distal end; a plurality of helical flutes extending along at least a portion of the body of the precision cutting tool; a plurality of radial cutting edges extending radially outward, each of the radial cutting edges being connected to one of the plurality of spiral flutes; a plurality of nose cutting edges extending distally outward at the distal end of the precision cutting tool, each nose cutting edge being coupled to one of the plurality of helical flutes; Including, The plurality of radial cutting edges and the plurality of nose cutting edges are configured to remove a quantity of material from the patient's bone to create an implantation cavity. Cutting structure and A precision cutting tool comprising:

15. 15. The precision cutting tool of claim 14, wherein the precision cutting tool includes at least five radial cutting edges and at least five helical flutes.

16. The precision cutting tool of claim 14, further comprising a central recessed area disposed at the distal end of the precision cutting tool.

17. The precision cutting tool of claim 14 , wherein the plurality of radial cutting edges comprises five or more radial cutting edges.

18. 15. The precision cutting tool of claim 14, wherein the plurality of nose cutting edges comprises five or more nose cutting edges.

19. 15. The precision cutting tool of claim 14, further comprising a plurality of helical flutes, each connected to one of the plurality of radial cutting edges.

20. 15. The precision cutting tool of claim 14, further comprising a plurality of helical flutes, each connected to one of the plurality of nose cutting edges.

21. 15. The precision cutting tool of claim 14, wherein each of the radial cutting edges includes a rake angle of about -20° to about 20°.

22. 14. The precision cutting tool of claim 13, wherein each of the radial cutting edges includes a clearance angle of about 3° to about 30°.

23. 15. The precision cutting tool of claim 14, wherein each of the nose cutting edges includes a rake angle of about -20° to about 20°.

24. 15. The precision cutting tool of claim 14, wherein each of the nose edges includes at least one flank surface having a clearance angle of from about 3° to about 45°.

25. 15. The precision cutting tool of claim 14, further comprising an outer diameter of the cutting structure of about 7 mm or greater.

26. 15. The precision cutting tool of claim 14, further comprising a safety stop at a predetermined location from the distal end of the precision cutting tool, thereby establishing a maximum penetration depth of the precision cutting tool.

27. 15. The precision cutting tool of claim 14, further comprising a safety stop, said safety stop being a distal end of said removable cover when said removable cover is fixedly attached to said precision cutting tool.

28. 15. The precision cutting tool of claim 14, wherein the proximal end is fixed or attachable to a rotatable connection on a drill surface.

29. 1. A method for establishing a large diameter burr hole in a patient, the method comprising: and creating an initial hole in the patient to create an implantation hole, the creating the initial hole comprising rotating a precision cutting tool within the initial hole, the precision cutting tool comprising: a proximal end opposite the distal end, with a body extending between the proximal end and the distal end; a plurality of helical grooves extending along at least a portion of the body; a plurality of radial cutting edges extending radially outward, each of the radial cutting edges being connected to one of the plurality of spiral flutes; a plurality of nose cutting edges extending distally outward at the distal end of the precision cutting tool, each nose cutting edge being connected to one of the plurality of spiral flutes; Including, The plurality of radial cutting edges and the plurality of nose cutting edges are configured to remove a quantity of material from the patient's bone to create an implantation cavity. Cutting structure and Including, method.

30. 30. The method of claim 29, wherein the precision cutting tool includes at least five radial cutting edges and at least five helical flutes.

31. 30. The method of claim 29, wherein the precision cutting tool further comprises a central recessed area disposed at the distal end of the precision cutting tool.

32. 30. The method of claim 29, wherein the plurality of radial cutting edges comprises five or more radial cutting edges.

33. 30. The method of claim 29, wherein the plurality of nose cutting edges comprises five or more nose cutting edges.

34. 30. The method of claim 29, wherein the precision cutting tool further comprises a plurality of helical flutes, each flute connected to one of the plurality of radial cutting edges.

35. 30. The method of claim 29, wherein the precision cutting tool further comprises a plurality of helical flutes, each flute connected to one of the plurality of nose cutting edges.

36. 30. The method of claim 29, wherein each of the radial cutting edges includes a rake angle of about -20 degrees to about 20 degrees.

37. 30. The method of claim 29, wherein each of the radial cutting edges includes a clearance angle of about 3 degrees to about 30 degrees.

38. 30. The method of claim 29, wherein each of the nose cutting edges includes a rake angle of about -20 degrees to about 20 degrees.

39. 30. The method of claim 29, wherein each of the nose cutting edges includes at least one flank having a clearance angle of about 3 degrees to about 30 degrees.

40. 30. The method of claim 29, wherein the cutting structure further comprises an outer diameter of about 7 mm or greater.

41. 30. The method of claim 29, wherein the precision cutting tool further comprises a safety stop located a predetermined distance from the distal end of the precision cutting tool, thereby establishing a maximum penetration depth of the precision cutting tool.

42. 30. The method of claim 29, wherein the precision cutting tool further comprises a safety stop, the safety stop being a distal end of the removable cover when the removable cover is fixedly attached to the precision cutting tool.

43. The proximal end of the precision cutting tool is secured to or attached to a rotatable connection on a drill surface.

30. The method of claim 29, wherein the

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