JPS6244939B2 - - Google Patents

Description

[Detailed Description of the Invention] Bone tumors of the humerus often cause not only destruction of bone and cartilage, but also widespread invasion of the soft tissues around the shoulder joint, including the rotator cuff.
Since extensive resection of bone and soft tissue is unavoidable, how to restore tissue defects after surgery is a major clinical problem. Based on many years of clinical experience, we have invented a humeral prosthesis head for bone tumors as a new humeral prosthesis material.

In the present invention, the femoral head is made of polycrystalline alumina ceramics and has a spherical shape with a diameter of 2r, r: 17 to 25.
mm, and the elevation angle α is preferably 130° to 140° with respect to the long axis of the stem on the spherical surface facing the scapular fossa.
The opening of the canal-like foramen Ratsupa forms an angle of 135°, and the foramen has a structure that protrudes toward the back of the femoral head.The opening of the canal-like fora Ratsupa has a circular or oval shape. In the case of a circular shape, the diameter is 5 to 20 mm, and in the case of an oval shape, the major axis is 10 to 25 mm, and the minor axis is 3 to 15 mm, and the exit of the small hole is circular with a diameter of 3 to 10 mm.

The long axis of the stem part passes through the center of the femoral head, and the part A corresponding to the diaphysis is made of polycrystalline alumina ceramics and has a cylindrical structure with a diameter of 17 to 23 mm, preferably 20 mm, and the stem part has a cylindrical structure with a diameter of 17 to 23 mm, preferably 20 mm. There are 10 to 20 small holes with a diameter of 1 to 4 mm, preferably 2 mm, penetrating the cylinder, and a part A corresponding to the diaphysis from the apex of the femoral head to the diaphysis.
The distance to the distal end of the tube shall be 60 to 180 mm.

Part B, which corresponds to the intramedullary nail, is made of single crystal alumina ceramics, diameter: 7 to 15 mm, length: 50 to
It has a 150mm cylindrical structure, with grooves in 2 to 4 places on the cylinder to prevent loosening, and the tip of the cylinder has several wings to prevent rotation, making it easy to enter the medullary cavity. It has been processed and processed to have an acute angle.

The artificial humeral head for bone tumors consists of an artificial ligament made of terylene or carbon fiber that is guided from outside the glenoid fossa of the scapula, through the scapular bone marrow, and through a small hole drilled in the center of the glenoid fossa. A structure is adopted in which the artificial ligament is received through the opening of the canal-like small foramen and exits to the dorsal exit, and at this time, a play of about 5 mm inside and outside of the artificial ligament is left between the scapular fossa and the artificial head, and both ends of the artificial ligament are Efforts have been made to make it difficult to fall out by creating a nodule.

By the way, radical surgery for bone tumors in the humerus requires not only resection of the humerus but also extensive resection of soft tissues such as muscles around the shoulder joint that are thought to have been infiltrated by tumor cells, resulting in tissue loss after surgery. Dislocation of the humeral prosthesis is inevitable due to the increased size of the humerus. Therefore, there is a need for an artificial humeral replacement with a built-in dislocation prevention device, and our artificial humeral head for bone tumors meets these expectations.

Regarding the shape of the femoral head of the artificial femoral head, in the shoulder joint, where the original anatomical order has been completely lost due to extensive tissue destruction due to a bone tumor, the shape of the femoral head of the artificial femoral head has been slightly changed by the strength of the deltoid muscles and other muscles that are left behind. However, in order to form a shoulder joint that is easy to move, a spherical shape with a high degree of freedom is considered optimal.In addition, by using an artificial ligament as a dislocation prevention device, it is possible to achieve the seemingly contradictory goals of ease of movement and prevention of dislocation. This makes possible the original form of the joint movement mechanism.

The artificial ligament used here is Terylene or carbon fiber, and Terylene, a type of synthetic polyester, has tissue conductivity comparable to that of carbon fiber, which is currently used worldwide. tissue
It has an elongation rate of 5%, the same as that of living ligaments, and has already been used as a material for artificial blood vessels, and its safety in living bodies has been proven. In particular, Leeds is made from terylene.
-Keio) The artificial ligament is made of terylene with a diameter of 8 to 10μ.
A strand is made from filament (Terylene filament), which is then plain woven into a mesh structure.However, the disadvantage of terylene, which has poor gripping power for tissue-induced new tissue, is best suited for gripping tissue that has proliferated. Appropriate structure, i.e. approx.
This was overcome by using a mesh structure of 2.5mm x 2.5mm, and the excessive elasticity of the mesh structure was also solved by using a plain weave.The warp threads support the stress applied to the ligament, and the weft threads reduce the misalignment of the warp threads. It is fulfilling its role. Furthermore, the artificial ligament has a tube-like structure (tube) with a diameter of 10 mm, and a new ligament with a desired shape is induced. Furthermore, regarding the problem of material fatigue, it has been confirmed in animal experiments that tissue-induced new ligaments acquire strength that exceeds that of the original ligaments before the fatigue phenomenon occurs, and this has already been demonstrated in clinical settings. It has been used for knee joint ligament injuries and excellent results have been reported. Regarding the artificial ligament,
This is a well-known fact, as described in the magazine Knee 8(2): 240-249, 1983.

In addition, several small holes made in part A, which corresponds to the diaphysis of the stem, are used as attachment points for muscles that are free from tumor cell invasion, and after being interrupted and sutured with strong nylon thread, etc. It is designed to serve as a new shoulder joint mobilization muscle. The thickness of the same portion is determined by X-ray measurements of the human humerus.

Part B corresponding to the intramedullary nail is made of single crystal alumina.
Made of ceramics, due to its physical and chemical stability and inertness, it has been proven to cause no harm when implanted in the body for a long period of time, and to have superior mechanical strength to metal screws of the same diameter. , designed to have a thickness that fits the human bone marrow cavity. Of course, highly harmful bone cement is not necessary for anchoring the stem.

Example In an artificial humeral head for bone tumors consisting of a femoral head and a stem, the femoral head is made of polycrystalline alumina ceramics and has a spherical shape with a diameter of 38 mm.
On the spherical surface facing the scapular fossa, the long axis of the stem and 135
A small foramen shaped like a canal of Ratsupa with an elevation angle of ° opens, and the small foramen has a structure that protrudes to the dorsal side of the femoral head. The exit part shall have a circular shape with a diameter of 5 mm, the long axis of the stem part passes through the center of the femoral head, and the part A corresponding to the diaphysis is made of polycrystalline alumina ceramics and has a cylindrical structure with a diameter of 20 mm. It has a structure in which small holes with a diameter of 2 mm are arranged vertically in three rows of five holes that penetrate the cylinder from front to back, and the distance from the apex of the femoral head to the distal end of part A corresponding to the diaphysis is
The length shall be 120mm.

Part B, which corresponds to the intramedullary nail, is made of single crystal alumina.
It has a cylindrical structure made of ceramics with a diameter of 11 mm and a length of 80 mm, and has three grooves to prevent loosening, and the tip of the cylinder is equipped with four-lobed wings to prevent rotation, preventing entry into the medullary cavity. To make it easier, it has been processed and processed into a sharp angle.

The artificial humeral head for bone tumors has a structure in which the Leeds-Keio artificial ligament guided from the scapular fossa is received through the opening of the Ratsupa canal-like foramen, exits to the dorsal exit, and connects to the glenoid fossa of the scapula. A 5 mm play of the artificial ligament is left between the femoral heads of the artificial femoral head, and a tubercle is created at both ends of the artificial ligament where it exits the scapula and the femoral head to prevent it from slipping out. Incidentally, the joint between portion A corresponding to the diaphysis of the stem portion and B corresponding to the intramedullary nail has been slightly devised as shown in FIGS. 1 and 2 to prevent rotation.

We have used the present invention in patients with bone tumors of the humerus, and have succeeded in creating stable and mobile shoulder joints.

It must be said that for patients with humeral bone tumors, whose survival is expected to be extended through early detection and advances in chemotherapy, it is of great significance for them to obtain a shoulder joint that is easy to move and is free from dislocation after tumor removal.

[Brief explanation of the drawing]

FIG. 1: Shows a front view of the artificial bone head of the present invention. The shaded area represents a cross-sectional view of the Ratsupa canal-like ostium. FIG. 2: Shows a view from the inside of the artificial bone head of the present invention. FIG. 3: Shows a top view of the artificial bone head of the present invention. FIG. 4: A diagram showing the present invention and the glenoid fossa of the scapula connected by an artificial ligament.

Claims (1)

[Claims] 1. In a humeral prosthetic head for bone tumors consisting of a femoral head and a stem, the femoral head has a spherical shape, and has an opening of a foramen similar to the canal of Ratsupa on the spherical surface facing the scapular fossa. The foramen exits to the dorsal side of the femoral head,
Through the same small hole, the scapular fossa and the artificial femoral head are connected by an artificial ligament, and the stem part that connects to the femoral head has a part A corresponding to the diaphysis with several small holes and an intramedullary nail. This artificial humeral head for bone tumors is divided into part B, and the femoral head and stem are made of ceramics.