Title of Invention	"A VERTEBRAL BODY DRILL"
Abstract	This invention titled as "Ravidev's drilling apparatus" relates to a surgical device for drilling vertebral bodies for anterior spinal cord decompression and fusion in patients with spinal problems. In the known art the traditional device (as used for Cloward's cervical procedure) is very cumbersome, not completely safe and has limitations in applicability. In the present invention there is no need to hammer the prongs and long sheath into the vertebrae as a tweaking cap with a lock ring is provided to adjust the drilling length of bur and a check ring is provided to check the forward movement of drill. Check ring diameter is adjustable according to the vertebral width exposed and available at surgery. A grip and a T-handle are provided for a stabilized, less cumbersome and unaided drilling force. These features make it a safer, less invasive and versatile device that provides better precision and facilitates in-process control while drilling.

Title of Invention

"A VERTEBRAL BODY DRILL"

Abstract

This invention titled as "Ravidev's drilling apparatus" relates to a surgical device for drilling vertebral bodies for anterior spinal cord decompression and fusion in patients with spinal problems. In the known art the traditional device (as used for Cloward's cervical procedure) is very cumbersome, not completely safe and has limitations in applicability. In the present invention there is no need to hammer the prongs and long sheath into the vertebrae as a tweaking cap with a lock ring is provided to adjust the drilling length of bur and a check ring is provided to check the forward movement of drill. Check ring diameter is adjustable according to the vertebral width exposed and available at surgery. A grip and a T-handle are provided for a stabilized, less cumbersome and unaided drilling force. These features make it a safer, less invasive and versatile device that provides better precision and facilitates in-process control while drilling.

Full Text	FIELD OF INVENTION A vertebral body drill relates to a surgical apparatus for drilling vertebral bodies at the anterior spinal operations for spinal cord decompression in the patients of cervical cord compression. BRIEF DESCRIPTION OF RELATED ART The cloward's apparatus known in prior art consists of a drilling shaft fitted in a brace. There is also a drill-guarding sheath that has sharp prongs at its distal end. There is a stop at the drilling shaft that stops the forward movement of drill by abutting with the proximal end of the drill-guarding sheath. Position of the stop is adjusted on the shaft to make a drill hole just equal to the anterior-posterior diameter of vertebral bodies. Drill-guarding sheath is fixed to the vertebral bodies by hammering its prongs into the vertebral bodies. Drill-guarding sheath is stabilized in place by holding it with a cross bar. Drilling shaft is then rotated through the sheath to make a hole in the vertebral bodies till the stop abuts with the sheath and stops further movement of drill. Drilling shaft and drill-guarding sheath is then removed from the vertebral bodies and decompression of spinal cord is accomplished through the hole made by drill. The demerits of conventional Cloward's apparatus are that:- (i) It is very cumbersome, as it has a brace, a drill guarding sheath, and a cross bar to hold the drill guarding sheath. (ii) It is not completely safe because sharp prongs of the drill-guarding sheath are hammered into the vertebral bodies. Hammering of sheath can damage the spinal cord by producing jerk trauma particularly in the degenerative spine. (iii) Sharp prongs of sheath create holes in the adjacent vertebral bodies. These holes weaken the vertebrae particularly in the elderly and is osteoporosis, and thus add to the weakening produced by drilling. (iv) An assistant is required for stabilizing the drill-guarding sheath by holding it with a cross bar. (v) The sheath is prone to become oblique instead of perpendicular to the anterior vertebral surface whenever there is - uneven anterior vertebral surface, incorrect neck positioning or uneven stabilization by the inadvertent hand movements of the assistant. That obliquity of the drill-guarding sheath may lead to uneven cutting of the vertebrae. (vi) The drill-guarding sheath does not allow the intermittent inspection of the hole while drilling, hence bleeding from the bone cannot be controlled promptly and bone cutting can not be readjusted. OBJECT OF THE INVENTION The object of the invention is to obviate the aforesaid demerits and to provide a safe and simple device for performing anterior cervical spine surgery. STATEMENT OF THE INVENTION Accordingly, the present invention provides a vertebral body drill apparatus for use in anterior spinal operation characterized in that the said body drill apparatus comprising: a shaft (3) having a handle (1) at its proximal end, said shaft being provided with external threads (8) and internal threads (9) at a segment (4) near its distal end; screwable burrs (11) having different size and shape removably provided with external threads at its proximal end for screwing into the internal threads of the shaft; a cylindrical adjustable cap (6) moveably provided on the external threads of the said shaft to cover or expose the underlying burr; a locking ring (5) moveably provided on the external threads of the said shaft for locating the locking ring above a proximal end of the cylindrical adjustable cap for locking the movement of the said adjustable cap; a stop ring (7) provided near a distal end of the said adjustable cap for stopping forward movement of burr. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The invention will be understood more clearly from the following description wherein one embodiment of the invention has been described for an example with the help of accompanying drawings in which salient constructional features have been shown by suitable numerals. Fig.l- shows the composite diagram of the vertebral body drill fitted with a flat burr. Fig.2- shows the drilling shaft after removing the burr, the adjustable cap and the locking ring. Fig.3- shows the internal features of the distal segment of the drilling shaft in a longitudinal sectional view along the line X marked in figure-2. Fig.4- shows the internal features of the adjustable cap in a longitudinal sectional view. Fig.5- shows a pointed burr. Fig.6- shows a flat burr. In all the figures, like numerals represent the like parts. Referring to the figures 1 to 6, the vertebral body drill (fig.l) according to this invention comprises of a drilling shaft (3) having a handle (1) fixed at its proximal end and a cylindrical grip (2) mounted near its proximal end. Distal end of drilling shaft (3) has a hollow segment (4) containing external threads (8) on its surface and internal threads (9) inside its lumen. External threads (8) on the surface of the distal end of drilling shaft holds a locking ring (5) and a cylindrical adjustable cap (6); both are movable up or down on these threads. Adjustable cap is having internal threads (10) in the lumen of its proximal portion to move on the external threads (8) of the drilling shaft in a manner that its downward movement covers and upward movement exposes the underlying burr. Locking ring (5) is also having threads in its inner surface to move on the external threads (8) of the drilling shaft. Locking ring (5) locks the upward movement of adjustable cap (6) at the measured position. A stop ring (7) is provided on the distal margin of the adjustable cap to stop the forward movement of drill on completion of drilling. Pointed burr (fig.5) and flat burr (fig.6) are provided in different diameters for drilling the vertebral bodies with the vertebral body drill. Each of the burrs is having a proximal segment of threads (11) to fit into the internal threads (9) of the drilling shaft. Working of the Invention: Inter-vertebral disc level to be operated is surgically exposed and depth of the disc space is measured. Drilling shaft (3) is fitted with a pointed burr (fig.5) and then adjustable cap (6) is moved down to cover the burr so that only distal 5mm of pointed burr is exposed for drilling. Adjustable cap is locked in this position by locking ring (5) so that it may not move upwards while drilling. The purpose of the pointed burr is to make a preliminary slot for subsequent drilling with the flat burr. The drilling shaft thus fitted with the pointed burr is placed at the inter-vertebral level, stabilized by the grip (2) and rotated by means of handle (1). Forward movement of drilling shaft beyond 5mm is checked by the stop ring (7) so burr cannot make a hole deeper than 5mm. Now pointed burr is removed and drilling shaft is fitted with a flat burr (fig.6). Adjustable cap is moved down to cover the flat burr till the exposed portion of the burr is equivalent to the depth of inter-vertebral disc space. Adjustable cap is now locked in this position by locking ring (5) so that it may not move upwards while drilling. Drilling shaft thus fitted with the flat burr is placed into the preliminary vertebral slot, stabilized by the grip (2) and rotated by means of handle (1). Forward movement of drilling shaft beyond measured depth is prevented by stop ring (7) hence burr can not make a hole deeper than the depth of inter-vertebral space. The pointed and the flat burrs are provided in different diameters to fulfill various requirements. Advantages:- The vertebral body drill according to this invention is safer as it is provided with an adjustable cap as a novel feature that needs not to be hammered into the vertebral bodies. Hence there is no chance of transmitted jerk trauma to spinal cord. There are no sharp pointed prongs in the vertebral body drill hence no chance of damage to the adjacent neurovascular structures, furthermore holes are not created in the vertebra hence no chance of weakening of vertebra. This vertebral body drill allows intermittent inspection of the hole during the process of drilling so bleeding from the vertebra can be controlled instantaneously; furthermore measurement and direction of the drilling can be readjusted to ensure a hole of appropriate depth and direction. There is no need to place a drill guarding sheath on the anterior vertebral surface hence no chance of deflection of the drilling shaft by the anteriorly projecting osteophytes and no assistance is needed for stabilizing the sheath. The adjustable cap with its stop ring is sleeker than the sheath and prongs of the conventional apparatus hence excessive retraction of surrounding structures is avoided and drilling can be easily performed even if there is narrow neck space e.g. C7-T1 level. It is non-cumbersome as brace and sheath are not needed. WE CLAIM: 1. A vertebra] body drill apparatus for use in anterior spinal operations, characterized in that the said body drill apparatus comprising: a shaft (3) having a handle (1) at its proximal end, said shaft being provided with external threads (8) and internal threads (9) at a segment (4) near its distal end; screwable burrs (11) having different size and shape irremovably provided with external threads at its proximal end for screwing into the internal threads of the shaft; a cylindrical adjustable cap (6) moveably provided on the external threads of the said shaft to cover or expose the underlying burr; a locking ring (5) moveably provided on the external threads of the said shaft for locating the locking ring above a proximal end of the cylindrical adjustable cap for locking the movement of the said adjustable cap; a stop ring (7) provided near a distal end of the said adjustable cap for stopping forward movement of burr. 2. A vertebral body drill apparatus as claimed in claim 1, wherein the shaft is provided with a grip (2) near its proximal end. 3. A vertebral body drill apparatus as claimed in claim 1, wherein the adjustable cap is provided with internal threads at its proximal end. 4. A vertebral body drill apparatus as claimed in claim 1, wherein the cylindrical adjustable cap and the stop ring are formed as a single unit or detachable parts. 5. A vertebral body drill apparatus as claimed in claim 1, wherein all the parts are made of stainless steel. 6. A vertebral body drill apparatus substantially as herein described with references to figures 1 to 6 of the accompanying drawings.

Full Text

FIELD OF INVENTION
A vertebral body drill relates to a surgical apparatus for drilling vertebral bodies at the anterior spinal operations for spinal cord decompression in the patients of cervical cord compression.
BRIEF DESCRIPTION OF RELATED ART
The cloward's apparatus known in prior art consists of a drilling shaft fitted in a brace. There is also a drill-guarding sheath that has sharp prongs at its distal end. There is a stop at the drilling shaft that stops the forward movement of drill by abutting with the proximal end of the drill-guarding sheath. Position of the stop is adjusted on the shaft to make a drill hole just equal to the anterior-posterior diameter of vertebral bodies. Drill-guarding sheath is fixed to the vertebral bodies by hammering its prongs into the vertebral bodies. Drill-guarding sheath is stabilized in place by holding it with a cross bar. Drilling shaft is then rotated through the sheath to make a hole in the vertebral bodies till the stop abuts with the sheath and stops further movement of drill. Drilling shaft and drill-guarding sheath is then removed from the vertebral bodies and decompression of spinal cord is accomplished through the hole made by drill. The demerits of conventional Cloward's apparatus are that:-
(i) It is very cumbersome, as it has a brace, a drill guarding sheath, and a cross bar to hold the drill guarding sheath.
(ii) It is not completely safe because sharp prongs of the drill-guarding sheath are hammered into the vertebral bodies. Hammering of sheath can damage the spinal cord by producing jerk trauma particularly in the degenerative spine.
(iii) Sharp prongs of sheath create holes in the adjacent vertebral bodies. These holes weaken the vertebrae particularly in the elderly and is osteoporosis, and thus add to the weakening produced by drilling.
(iv) An assistant is required for stabilizing the drill-guarding sheath by holding it with a cross bar.
(v) The sheath is prone to become oblique instead of perpendicular to the anterior vertebral surface whenever there is - uneven anterior vertebral surface, incorrect
neck positioning or uneven stabilization by the inadvertent hand movements of the assistant. That obliquity of the drill-guarding sheath may lead to uneven cutting of the vertebrae.
(vi) The drill-guarding sheath does not allow the intermittent inspection of the hole while drilling, hence bleeding from the bone cannot be controlled promptly and bone cutting can not be readjusted.
OBJECT OF THE INVENTION
The object of the invention is to obviate the aforesaid demerits and to provide a safe and simple device for performing anterior cervical spine surgery.
STATEMENT OF THE INVENTION
Accordingly, the present invention provides a vertebral body drill apparatus for use in anterior spinal operation characterized in that the said body drill apparatus comprising: a shaft (3) having a handle (1) at its proximal end, said shaft being provided with external threads (8) and internal threads (9) at a segment (4) near its distal end; screwable burrs (11) having different size and shape removably provided with external threads at its proximal end for screwing into the internal threads of the shaft; a cylindrical adjustable cap (6) moveably provided on the external threads of the said shaft to cover or expose the underlying burr; a locking ring (5) moveably provided on the external threads of the said shaft for locating the locking ring above a proximal end of the cylindrical adjustable cap for locking the movement of the said adjustable cap; a stop ring (7) provided near a distal end of the said adjustable cap for stopping forward movement of burr.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention will be understood more clearly from the following description wherein one embodiment of the invention has been described for an example with the help of accompanying drawings in which salient constructional features have been shown by suitable numerals.
Fig.l- shows the composite diagram of the vertebral body drill fitted with a flat burr.
Fig.2- shows the drilling shaft after removing the burr, the adjustable cap and the locking
ring.
Fig.3- shows the internal features of the distal segment of the drilling shaft in a
longitudinal sectional view along the line X marked in figure-2.
Fig.4- shows the internal features of the adjustable cap in a longitudinal sectional view.
Fig.5- shows a pointed burr.
Fig.6- shows a flat burr.
In all the figures, like numerals represent the like parts.
Referring to the figures 1 to 6, the vertebral body drill (fig.l) according to this invention
comprises of a drilling shaft (3) having a handle (1) fixed at its proximal end and a
cylindrical grip (2) mounted near its proximal end. Distal end of drilling shaft (3) has a
hollow segment (4) containing external threads (8) on its surface and internal threads (9)
inside its lumen. External threads (8) on the surface of the distal end of drilling shaft
holds a locking ring (5) and a cylindrical adjustable cap (6); both are movable up or down
on these threads. Adjustable cap is having internal threads (10) in the lumen of its
proximal portion to move on the external threads (8) of the drilling shaft in a manner that
its downward movement covers and upward movement exposes the underlying burr.
Locking ring (5) is also having threads in its inner surface to move on the external threads
(8) of the drilling shaft. Locking ring (5) locks the upward movement of adjustable cap
(6) at the measured position. A stop ring (7) is provided on the distal margin of the
adjustable cap to stop the forward movement of drill on completion of drilling. Pointed
burr (fig.5) and flat burr (fig.6) are provided in different diameters for drilling the
vertebral bodies with the vertebral body drill. Each of the burrs is having a proximal
segment of threads (11) to fit into the internal threads (9) of the drilling shaft.
Working of the Invention: Inter-vertebral disc level to be operated is surgically
exposed and depth of the disc space is measured. Drilling shaft (3) is fitted with a pointed
burr (fig.5) and then adjustable cap (6) is moved down to cover the burr so that only
distal 5mm of pointed burr is exposed for drilling. Adjustable cap is locked in this
position by locking ring (5) so that it may not move upwards while drilling. The purpose
of the pointed burr is to make a preliminary slot for subsequent drilling with the flat burr.
The drilling shaft thus fitted with the pointed burr is placed at the inter-vertebral level, stabilized by the grip (2) and rotated by means of handle (1). Forward movement of drilling shaft beyond 5mm is checked by the stop ring (7) so burr cannot make a hole deeper than 5mm. Now pointed burr is removed and drilling shaft is fitted with a flat burr (fig.6). Adjustable cap is moved down to cover the flat burr till the exposed portion of the burr is equivalent to the depth of inter-vertebral disc space. Adjustable cap is now locked in this position by locking ring (5) so that it may not move upwards while drilling. Drilling shaft thus fitted with the flat burr is placed into the preliminary vertebral slot, stabilized by the grip (2) and rotated by means of handle (1). Forward movement of drilling shaft beyond measured depth is prevented by stop ring (7) hence burr can not make a hole deeper than the depth of inter-vertebral space. The pointed and the flat burrs are provided in different diameters to fulfill various requirements. Advantages:- The vertebral body drill according to this invention is safer as it is provided with an adjustable cap as a novel feature that needs not to be hammered into the vertebral bodies. Hence there is no chance of transmitted jerk trauma to spinal cord. There are no sharp pointed prongs in the vertebral body drill hence no chance of damage to the adjacent neurovascular structures, furthermore holes are not created in the vertebra hence no chance of weakening of vertebra. This vertebral body drill allows intermittent inspection of the hole during the process of drilling so bleeding from the vertebra can be controlled instantaneously; furthermore measurement and direction of the drilling can be readjusted to ensure a hole of appropriate depth and direction. There is no need to place a drill guarding sheath on the anterior vertebral surface hence no chance of deflection of the drilling shaft by the anteriorly projecting osteophytes and no assistance is needed for stabilizing the sheath. The adjustable cap with its stop ring is sleeker than the sheath and prongs of the conventional apparatus hence excessive retraction of surrounding structures is avoided and drilling can be easily performed even if there is narrow neck space e.g. C7-T1 level. It is non-cumbersome as brace and sheath are not needed.

WE CLAIM:
1. A vertebra] body drill apparatus for use in anterior spinal operations, characterized in
that the said body drill apparatus comprising:
a shaft (3) having a handle (1) at its proximal end, said shaft being provided with external threads (8) and internal threads (9) at a segment (4) near its distal end;
screwable burrs (11) having different size and shape irremovably provided with external threads at its proximal end for screwing into the internal threads of the shaft;
a cylindrical adjustable cap (6) moveably provided on the external threads of the said shaft to cover or expose the underlying burr;
a locking ring (5) moveably provided on the external threads of the said shaft for locating the locking ring above a proximal end of the cylindrical adjustable cap for locking the movement of the said adjustable cap;
a stop ring (7) provided near a distal end of the said adjustable cap for stopping forward movement of burr.
2. A vertebral body drill apparatus as claimed in claim 1, wherein the shaft is provided
with a grip (2) near its proximal end.
3. A vertebral body drill apparatus as claimed in claim 1, wherein the adjustable cap is
provided with internal threads at its proximal end.
4. A vertebral body drill apparatus as claimed in claim 1, wherein the cylindrical
adjustable cap and the stop ring are formed as a single unit or detachable parts.
5. A vertebral body drill apparatus as claimed in claim 1, wherein all the parts are made
of stainless steel.
6. A vertebral body drill apparatus substantially as herein described with references to
figures 1 to 6 of the accompanying drawings.

Documents:

288-del-2001-abstract.pdf

288-del-2001-claims.pdf

288-del-2001-correspondence-others.pdf

288-del-2001-correspondence-po.pdf

288-del-2001-description (complete).pdf

288-del-2001-drawings.pdf

288-del-2001-form-1.pdf

288-del-2001-form-13.pdf

288-del-2001-form-19.pdf

288-del-2001-form-2.pdf

288-del-2001-form-26.pdf

288-del-2001-form-3.pdf

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Patent Number

230362

Indian Patent Application Number

288/DEL/2001

PG Journal Number

11/2009

Publication Date

13-Mar-2009

Grant Date

26-Feb-2009

Date of Filing

13-Mar-2001

Name of Patentee

DR. RAVI DEV

Applicant Address

225, RAJENDRA NAGAR, LUCKNOW-226004, UTTAR PRADESH, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	RAVI DEV	225, RAJENDRA NAGAR, LUCKNOW, UTTAR PRADESH, INDIA.

PCT International Classification Number

A61 B17/56

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA