# US 7,608,077 B2 · Method and apparatus for spinal distraction and fusion

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- Number: US 7,608,077 B2
- Document ID: US7608077B2
- Status: Granted
- Kind: B2
- Application number: 11/189,943
- Filed: 2005-07-26
- Published: 2005-11-24
- Granted: 2009-10-27
- Earliest claimed: 2000-02-16
- Assignees: TranS1 Inc.
- Inventors: Andrew H. Cragg; Robert L. Assell; Eugene A. Dickhudt
- Web page: https://patentgrep.com/patent/US7608077B2

## CPC

- A61F 2/4611: {of spinal prostheses}
- A61B 17/1671: {for the spine}
- A61B 17/1757: {for the spine}
- A61B 17/32002: {with continuously rotating, oscillating or reciprocating cutting instruments}
- A61B 17/70: Spinal positioners or stabilisers, e.g. stabilisers comprising fluid filler in an implant
- A61F 2/441: {made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel}
- A61F 2/4465: {having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine}
- A61F 2/4601: {for introducing bone substitute, for implanting bone graft implants or for compacting them in the bone cavity}
- A61B 17/320725: {with radially expandable cutting or abrading elements (A61B17/32075 takes precedence)}
- A61B 17/66: {Alignment}, compression or distraction mechanisms
- A61B 17/7055: {connected to sacrum, pelvis or skull}
- A61B 17/7061: {for stabilising vertebrae or discs by improving the condition of their tissues, e.g. using implanted medication or fluid exchange (intraosseous injection devices A61B17/3472)}
- A61B 17/8811: {characterised by the introducer tip, i.e. the part inserted into or onto the bone}
- A61B 2017/00004: {(bio)absorbable, (bio)resorbable or resorptive}
- A61B 2017/00261: {Discectomy}
- A61B 2017/00557: {inflatable (A61B2017/22051 takes precedence)}
- A61B 2017/00734: {battery operated}
- A61B 2017/00867: {shape memory effect}
- A61B 2017/2905: {flexible}
- A61B 2017/320012: {Brushes}
- A61B 2017/320733: {with a flexible cutting or scraping element, e.g. with a whip-like distal filament member}
- A61B 2017/564: {Methods for bone or joint treatment}
- A61F 2/30723: {Plugs or restrictors for sealing a cement-receiving space (tools for inserting plugs A61F2/4614; sealing collars for use during cementing A61B17/8808)}
- A61F 2/442: {Intervertebral or spinal discs, e.g. resilient (non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455)}
- A61F 2/4455: {for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages (intervertebral discs A61F2/442)}
- A61F 2002/2817: {Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]}
- A61F 2002/2835: {Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material}
- A61F 2002/30092: {using shape memory or superelastic materials, e.g. nitinol}
- A61F 2002/30233: {Stepped cylinders, i.e. having discrete diameter changes}
- A61F 2002/30235: {tubular, e.g. sleeves}
- A61F 2002/3055: {for adjusting length}
- A61F 2002/30563: {having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers}
- A61F 2002/30593: {hollow}
- A61F 2002/30677: {Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body}
- A61F 2002/30774: {internally-threaded}
- A61F 2002/30784: {Plurality of holes}
- A61F 2002/3085: {with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface}
- A61F 2002/30859: {having threaded portions of different pitches}
- A61F 2002/30879: {Ribs}
- A61F 2002/448: {comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants}
- A61F 2210/0014: using shape memory or superelastic materials, e.g. nitinol
- A61F 2230/0069: cylindrical
- A61F 2310/00023: Titanium or titanium-based alloys, e.g. Ti-Ni alloys
- A61F 2310/00796: Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
- A61F 2310/00976: Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

The invention provides an implantable spinal distraction/fusion rod with varied thread pitch and diameters along different portions of its length that it is capable of distracting two or more vertebral bodies relative to each other and/or facilitating the procedure of fusing the vertebral bodies together from within the spine. The present invention also provides for methods of using the rod to distract and/or fuse two or more vertebral bodies from within the spine.

## Claims

### Claim 1

An axially-extending implantable rod for adjusting a distance between two adjacent vertebral bodies in a spine, said rod comprising:
an elongated body dimensioned for implantation along an axis extending from an access point on the anterior surface of the sacrum and for maintaining the distance between the two adjacent vertebral bodies;
a first section near a leading end of the rod that has a first threading for engaging with a first vertebral body, the first threading comprising a first major diameter and a first minor diameter;
a second section near a trailing end of the rod that has a second threading for engaging with a second vertebral body that is located inferiorly relative to the first vertebral body, the second threading comprising a second major diameter and a second minor diameter;
an intermediate section extending between the distal and proximal sections, the intermediate section being sized and configured for maintaining the distance between the two vertebral bodies;
a central lumen extending axially from the trailing end into the body; and
at least one transverse aperture extending through the wall of the intermediate section and in communication with the lumen;
wherein the first major diameter of the first threading is less than the second major diameter of the second threading;
wherein a first thread pitch in the first section is finer relative to a second thread pitch in the second section such that advancement of the first section distally into the first vertebral body by rotation causes an increase in distance between the first and second vertebral bodies.

### Claim 2 (depends on 1)

The implantable rod according to claim 1, wherein the rod includes a central lumen extending axially from the trailing end into the body, the at least one side aperture being in communication with the lumen and the body being substantially solid in the first section.

### Claim 3 (depends on 1)

The implantable rod according to claim 1, wherein a ratio of the axial length of the second threading to the second minor diameter is within the range of approximately 1.27 to 3.53.

### Claim 4 (depends on 1)

The implantable rod according to claim 1, wherein the first section further comprises a first minor diameter, and a ratio of the axial length of the first threading to the first minor diameter is within the range of approximately 2.12 to 5.29.

### Claim 5 (depends on 1)

The implantable rod according to claim 1, wherein the second major diameter is within the range of from about 10 mm to about 15 mm.

### Claim 6 (depends on 1)

The implantable rod according to claim 1, wherein the first major diameter is no greater than about 98% of the second major diameter.

### Claim 7 (depends on 1)

The implantable rod according to claim 1, wherein the elongated body has a length within the range of from about 1.25 inches to about 2.25 inches.

### Claim 8 (depends on 1)

The implantable rod according to claim 1, wherein each of the first threading and the second threading has an axial length within the range of from about 0.5 inches to about 1.25 inches.

### Claim 9 (depends on 1)

The implantable rod according to claim 1, wherein the intermediate section has an axial length within the range of from about 0.25 inches to about 0.5 inches.

### Claim 10 (depends on 1)

The implantable rod according to claim 1, wherein the elongated body comprises stainless steel.

### Claim 11 (depends on 1)

The implantable rod according to claim 1, wherein the elongated body comprises titanium.

### Claim 12 (depends on 1)

The implantable rod according to claim 1, wherein the elongated body comprises a bioabsorbable material.

### Claim 13 (depends on 1)

The implantable rod according to claim 1, wherein the elongated body comprises a lumen extending axially at least part way through the length of the elongated body.

### Claim 14 (depends on 13)

The implantable rod according to claim 13, wherein the elongated body further comprises a plurality of side apertures in connection with the lumen.

### Claim 15

The implantable rod according to any preceding claim, wherein each of the first threading and the second threading extends counterclockwise around the body.

### Claim 16 (depends on 1)

The implantable rod according to any of claim 1, wherein each of the first threading and the second threading extends clockwise around the body.

### Claim 17 (depends on 1)

The implantable rod according to claim 1, wherein each of the first threading and the second threading are self tapping.

### Claim 18 (depends on 1)

The implantable rod according to claim 1, wherein the second major diameter is within the range of from about 12 mm to about 13 mm.

### Claim 19 (depends on 1)

The implantable rod according to claim 1, wherein the first major diameter is about 9 mm.

### Claim 20 (depends on 1)

The implantable rod according to claim 1, wherein the second thread pitch is within the range of from about 10 to about 15 turns per inch.

### Claim 21 (depends on 1)

The implantable rod according to claim 1, wherein the first thread pitch is within the range of from about 10 to about 20 turns per inch.

### Claim 22 (depends on 1)

The implantable rod according to claim 1, wherein the first thread pitch is at least about 105% finer than the second thread pitch.

### Claim 23 (depends on 1)

The implantable rod according to claim 1, wherein the first thread pitch is at least about 110% finer than the second thread pitch.

### Claim 24 (depends on 1)

The implantable rod according to claim 1, wherein the first thread pitch is at least about 125% finer than the second thread pitch.

### Claim 25 (depends on 1)

The implantable rod according to claim 1, further comprising a releasable coupling, for releasably engaging a rotatable driver tool.