JPH07102B2 - Spinal fixation thread - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a spinal fixation thread.

(Prior Art) Conventionally, in the treatment of fractures of the spine, scoliosis, kyphosis, deformity, etc., a fixation technique using a Rookie rod has been known as one of the spinal fixation methods. The patient's spinal column is fixed under the arches through the arches to maintain the corrective position. However, there is a possibility that the spinal cord may be erroneously pressed when the stainless wire is fixed during the operation, or the spinal cord may be damaged by the stump of the wire remaining in the spinal canal after the operation. However, there is a case where a metal reaction occurs due to the contact between the subcutaneous tissue and the stainless steel wire, or when microwave treatment is performed, electromagnetic waves are concentrated and heat is generated, which may cause burns. Careful attention is required on this occasion.

In order to prevent such defects of stainless steel wire,
It is recommended to use a fastener (Partridge bands) that has a retaining portion at one end of a nylon band that is commercially available for treating bone fractures and that has a smaller size and is used as a strap. [JBO'Brien et al., Clinical Ort
hopaedics and Related Researh 203: 168−171 (198
6)) (Problems to be solved by the invention) However, since the above-mentioned strap has a relatively small strength per unit thickness, it needs to be fairly thick, which may result in a large area occupied by the strap in the spinal canal. It is unavoidable, and since the strap is rigid, it remains a nerve risk as in the case of the stainless wire described above.

In recent years, a method of fixing the upper cervical vertebra using a silk suture has been reported. (Tamikazu Amago, New Clinical Orthopedics, Vol. 4-A, pages 257-277, Kanehara Publishing. 1984) However, this method is limited to cervical spine fixation, and requires strict external fixation with a cast after surgery However, silk sutures and conventional sutures made of polypropylene, polyester, or synthetic fibers such as nylon are not satisfactory for fixing the spine, particularly in terms of knot strength.

(Means for Solving Problems) The inventors of the present invention have been able to provide a material that does not have the inconvenience of the above-mentioned stainless wire or nylon strap and effectively fixes the spine regardless of the patient's age or spine site. As a result of intensive studies, the inventors have found that the ultrahigh molecular weight polyethylene fiber or the aramid fiber is extremely tough and highly flexible, and thus is useful as a material for orthodontic fixation and completed the present invention.

That is, the present invention is a spinal fixation yarn characterized by being braided with a synthetic fiber having a tensile strength (g / d) of 16 or more.

Examples of the fibers satisfying the above-mentioned strength include the above-mentioned ultra high molecular weight polyethylene and aramid fiber.

Ultra high molecular weight polyethylene (hereinafter sometimes abbreviated as PE)
Is a high-density polymer characterized by high elasticity and high strength, and can be obtained, for example, from Mitsui Petrochemical Co., Ltd. under the trade name of Techmilon. Aramid fiber (hereinafter AM
Is an aromatic polyamide fiber characterized by having high strength and high modulus. It is a generic name named by the US Federal Commerce Commission and is sold by the DuPont Company under the product name Kevlar. Has been done.

The properties of both fibers are shown in Table 1, and because they have extremely high strength and elasticity as compared with other synthetic fibers, they are suitable as spinal fixation materials, but are commercially available multifilaments. When used as a material for orthopedic orthodontic fixation, problems such as multifilament flapping and fluffing occur, so it is desirable to use in braided form.

(Example) In the case of PE multifilament, one core is used as the core, 12 cores are used for the outer circumference, and in the case of the AM multifilament, one core is used as the core and 8 cores are used for the outer circumference, and each is braided by a conventional method.
It was made into a braided yarn with a thickness of No. (0.50 to 0.599 m / m). In addition, a conventional silk braid and a stainless steel wire having the same number are prepared, and the length of the braided yarn according to the present invention is 10
Ten tensile testers (RTM-100 type, manufactured by Toyo Baldwin Co., Ltd.) were used to test each of 10 pieces at 0 mm crosshead speed of 100 mm / min. The results are shown in Table 2 as an average value.

Further, when the spine is fixed using the above-mentioned four kinds of threads, the fixing force of the silk blade is insufficient and there is a concern that the strength will decrease with time. On the other hand, the PE system and the AM system were able to tie up to the desired point, and the knot was small, and the spine could be fixed properly.

(Effect of the invention) As described above, the spinal fixation yarn according to the present invention has a tensile strength (g / g)
d) is braided with 16 or more synthetic fibers, has flexibility similar to conventional surgical sutures made of nylon, polyester, polypropylene, etc., and is used for conventional surgical sutures. Gamma-ray sterilization and EOG sterilization are applicable, and since it has extremely high strength, it is most suitable for spinal fixation. Moreover, unlike the stainless wire, it does not hinder radiography, so it is easy to determine the bone union after surgery, and the nodule work is simple.
In addition, since the knot can be accurately knotted and the knot strength is large, there is almost no trouble after the operation, which is a great effect.

Claims (3)

[Claims] 1. A spinal fixation yarn braided with a synthetic fiber having a tensile strength (g / d) of 16 or more. 2. The spinal fixation yarn according to claim 1, wherein the synthetic fiber is an ultra high molecular weight polyethylene fiber. 3. The spinal fixation yarn according to claim 1, wherein the synthetic fiber is an aramid fiber.