JPH0563512U - Curved chisel - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] Safe and easy cutting of cancellous bone in the vertebral body. The curved chisel 16 includes a shaft 1, a cutting portion 2 provided at one end of the shaft 1, and a handle 3 provided at the other end of the shaft 1. A root portion of the cutting portion 2 has a curved portion A having a predetermined radius of curvature, and a tip of a straight portion B connected to the curved portion A is provided with a cutting edge so that the vertebral body can be cut when cutting the cancellous bone of the vertebral body. It can be inserted smoothly into the back, avoiding the adjacent spinal nerve and epidural venous plexus, and the cutting edge does not cut into the spinal nerve and epidural venous plexus.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a curved chisel, and more particularly to a curved chisel suitable for correction of scoliosis and kyphoscoliosis due to spinal deformity.

[0002]

[Prior Art]

 Humans have 32 vertebrae from just below the head to below the waist. The vertical connection of these vertebrae is called the vertebral column, and they are classified into five parts from the top, the cervical vertebra, the thoracic vertebra, the lumbar vertebra, the sacral vertebra, and the tail vertebra. The shape of the spine is slightly different for each part, but it is common in that there is a round vertebral body on the abdominal side and an arcuate arch on the back side.

As shown in FIG. 16, the spine L 1 includes spinous processes 23, vertebral arches 21, lateral processes 4, 4, pedicles 5, 5 and vertebral bodies 6. A vertebra 7 is formed by the vertebral arch 21 and the vertebral body 6, and the vertebra 7 accommodates a spinal nerve 9 which is surrounded by a dura 8. Further, the spine L1 is surrounded by the back muscles 10 and 10 and the psoas muscles 11 and, and near the abdominal side of the vertebral body 6, there are an aorta 12 and an inferior vena cava 13.

By the way, an intervertebral disc is interposed between the vertebral bodies 6 in order to avoid direct contact between the vertebral bodies, but the elasticity of the intervertebral disc decreases as the age increases. As a result, the vertebral body 6 is deformed. This deformation of the vertebral body 6 causes a disease in which the spinal column S bends abnormally, that is, a high degree of scoliosis / kyphoscoliosis (see FIG. 17).

In order to correct severe scoliosis / kyphoscoliosis, osteotomy of the spine L 1 around the entire periphery of the spinal nerve 9 is required, and the spinal nerve 9 has osteophytes, ossification lesions, etc. Even if it is compressed by, the osteotomy of the spine L1 around the entire periphery of the spinal nerve 9 is necessary to remove the compression.

Conventionally, corrective surgery for scoliosis and kyphoscoliosis, which requires osteotomy of the spine L1, has been performed from both the abdominal side and the back side.

[0007]

[Problems to be solved by the device]

 The site to be operated is a place where important blood vessels such as the spinal nerve or aorta, the inferior vena cava, or the epidural venous plexus that control movement and perception are intermingled. There is a problem that corrective surgery for scoliosis and kyphoscoliosis is difficult because it is necessary to cut the bone, remove the periosteum, cut the bone, and particularly cut the cancellous bone.

The present invention has been made in view of such circumstances, and an object thereof is to provide a curved chisel capable of safely and easily cutting cancellous bone of a vertebral body.

[0009]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the bending chisel of the present invention comprises a shaft portion, a cutting portion provided at one end of the shaft portion, and a handle portion provided at the other end of the shaft portion. In the curved chisel for cutting cancellous bone, it is characterized in that the root portion of the cutting portion has a curved portion having a predetermined radius of curvature, and a linear portion extending linearly is connected to the root portion.

[0010]

[Action]

 As described above, the root portion of the cutting portion has a curved portion with a predetermined radius of curvature, and the straight portion that extends straight is connected to this root portion.Therefore, when inserting the cutting portion into the vertebral body, It can be inserted smoothly into the central vertebral body avoiding the spinal nerve and epidural venous plexus adjacent to the body, and the cancellous bone can be easily cut without the cutting edge cutting into the spinal nerve or epidural venous plexus. ..

[0011]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. 1a is a side view showing a curved chisel according to an embodiment of the present invention, FIG. 1b is a sectional view of the curved chisel, and FIG. 2 is a plan view thereof. The curved chisel 16 of the present invention has a cylindrical shaft 1, a cutting portion 2 is provided at the tip of the shaft 1, and a handle 3 is provided at the root of the shaft 1. The cross section of the cutting part 2 is flat (FIG. 1b), and the cross section of the shaft 1 is circular. As shown in FIG. 1a, the base of the cutting portion 2 with respect to the shaft 1 has a curved portion A 1 having a radius of curvature of, for example, 20 R (mm), and the curved portion A 2 has an imaginary line X 1 parallel to the axis of the shaft 1. A straight line portion B extending at a predetermined angle θ, for example, an angle of 15 ° ± 2 ° is connected. At the tip of the straight portion B, for example, a right- or left-curved blade edge 2a having a length of 7 (mm) is provided (FIG. 2). FIG. 2b shows a case where the cutting edge is right-curved. An oblique flat surface 2d is formed on the cutting edge 2a, a curved surface 2c is connected to this flat surface 2d, and the curved surface 2b faces the curved surface 2c. The cutting edge 2a is provided at the intersection of the curved surface 2b and the inclined flat surface 2d. A seam J is provided in the middle of the shaft 1, and the shaft 1 is welded to the seam J. A plurality of grooves 1a along the axis are formed in the root portion of the shaft 1, and the root portion of the shaft 1 is driven and joined to the connecting hole 3a of the handle 3.

Next, a case where this curved chisel is used for corrective surgery for kyphosis will be described with reference to FIGS. 3 to 15. As shown in FIG. 3, most of the vertebra L1 between both vertebrae L2 and L3 is removed by removing the vertebral body pieces C and D, and the vertebral body pieces C and D are left. Try to overlap D.

First, as shown in FIG. 4, the spine L1 is incised from the back side, the back muscles 10, 10 on both sides are opened laterally, and the vertebral arch 21, spinous process 23, and lateral processes 4, 4 are exposed. .. Next, after the transverse projections 4 and 4 are cut into bones, as shown on the left side of FIG. As shown on the right side of the figure, the retractor 14 is inserted and the psoas muscle 11 is deployed to secure the visual field.

After the periosteum on the outer periphery of the vertebral body 6 is separated by the dissector 22, the psoas muscles 11 and 11 are expanded to both sides by the two retractors 14 and 14 to secure the visual field (FIG. 6), and the spinous process 23 and The pedicle 21 is cut to expose the dura 8 (FIGS. 6 and 7). There is an epidural venous plexus 15 between the dura 8 and the vertebral body 6, and if this site is damaged, it will bleed and it will be difficult to secure a visual field.

Next, the pedicles 5, 5 and part of the vertebral body 6 are cut (FIG. 8), and the aorta 12 and the inferior vena cava 13 are protected by the two retractors 14, 14. The inside of the vertebral body 6 is cut off by cutting the cancellous bone 6c with the curved chisel 16 leaving the entire cortical bone 6a on the back side of the vertebral body 6 and a part of the cortical bone 6b on the abdominal side (FIGS. 8 and 9). It is dug up to form a hollow state.

As described above, the root of the cutting portion 2 of the curved chisel 16 has the curved portion A having a predetermined radius of curvature, and the straight portion B connected to the curved portion A is provided with the cutting edge, so When cutting the cancellous bone 6c in the body 6, the spinal nerve 9 and the epidural venous plexus 15 adjacent to the vertebral body 6 can be avoided and smoothly inserted into the interior of the vertebral body 6. That is, according to the curved chisel 16, the cutting edge of the cutting portion 2 can be inserted deep into the vertebral body 6 without cutting into the spinal nerve 9 or the epidural venous plexus 15, and the cancellous bone 6c can be cut safely and easily. it can.

Further, the cortical bone 6a on the back side adjacent to the epidural venous plexus 15 described above is cut. A corneal bone cutting chisel 17 is inserted from the side of the cortical bone 6a (FIGS. 10 and 11) to cut the cortical bone 6a so as not to damage the epidural venous plexus 15. After peeling the cortical bone 6a from the epidural venous plexus 15, burrs 6d and 6d remain as shown in FIG. 12, and then the burrs 6d and 6d of the cortical bone 6a are removed by the deburring chisel 18 (see FIG. 12). After deburring, the plate-shaped vertebral body piece C and the vertebral body piece D (FIG. 13) extending from the cortical bone 6b to the open state are joined as shown in FIG. 14 to correct the curvature. Finally, in order to maintain this corrected state, the vertebrae L2 and L3 above and below the vertebral body pieces C and D are connected by a fixing device (FIG. 15).

This fixing device is composed of screws 19a and 19b that are driven into the vertebrae L2 and L3 and a rod 20 that connects the outer ends of these screws 19a and 19b. Is provided with a female screw, and a male screw is threaded on the outer periphery of the rod 20. The screws 19a and 19b are embedded in the vertebrae L2 and L3, respectively, and the rod 20 is screwed onto the heads of the screws 19a and 19b to fix and hold the vertebral body pieces C and D in contact with each other to bend the spinal column S. To correct.

[0019]

[Effect of the device]

 As described above, according to the curved chisel of the present invention, when cutting the cancellous bone of the vertebral body, it can be smoothly inserted deep into the vertebral body while avoiding the spinal nerve and the epidural venous plexus. The cancellous bone can be cut safely and easily without the cutting edge of the cutting member cutting into the spinal nerve or epidural venous plexus.

[Brief description of drawings]

1a is a side view of a curved chisel according to one embodiment, and FIG. 1b is a sectional view taken along line Ib-Ib of FIG. 1a.

2a is a plan view of a curved chisel, and FIG. 2b is an enlarged plan view of a cutting edge of the curved chisel.

FIG. 3 is an explanatory diagram of a curved correction state.

FIG. 4 is a transverse cross-sectional view of the spine when the back side is incised.

FIG. 5 is a transverse cross-sectional view of the spine showing the use of the dissector and retractor.

FIG. 6 is a transverse cross-sectional view of the spine when the psoas muscle is deployed by the retractor.

FIG. 7 is a side view of the spine in the state of FIG.

FIG. 8 is a transverse cross-sectional view of the spine showing a state in which the pedicle and a part of the vertebral body are cut off.

FIG. 9 is a transverse cross-sectional view of the spine showing osteotomy of the cancellous bone of the vertebral body with a curved chisel.

FIG. 10 is a transverse cross-sectional view of a spine showing osteotomy of cortical bone of a vertebral body with a flea for cutting cortical bone.

FIG. 11 is a longitudinal cross-sectional view of a spine showing osteotomy of cortical bone of a vertebral body with a flea for cutting cortical bone.

FIG. 12 is a longitudinal sectional view of the spine showing deburring of cortical bone with a chisel for deburring.

FIG. 13 is a longitudinal sectional view of the spine after deburring.

FIG. 14 is a side view showing a joined state of the cervical body piece on the neck side and the vertebral body piece on the leg side.

FIG. 15 is an explanatory view showing a mounting state of a fixing tool for correcting a curvature.

FIG. 16 is a transverse cross-sectional view of the spine.

FIG. 17 is an explanatory diagram illustrating typical kyphosis of the spinal column.

[Explanation of symbols]

 1 ... Shaft 2 ... Cutting part 3 ... Handle 16 ... Curved chisel A ... Curved part B ... Straight part

Claims (1)

[Scope of utility model registration request] 1. A curved chisel for cutting cancellous bone of a vertebral body, comprising a shaft portion, a cutting portion provided at one end of the shaft portion, and a handle portion provided at the other end of the shaft portion. A curved chisel characterized in that a root portion of the portion has a curved portion with a predetermined radius of curvature, and a linear portion extending linearly is connected to the root portion.