RU2675339C2 - Combined annular drilling for blind holes in bone tissue - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention relates to medicine. Combined circular drill for blind holes in the bone tissue contains a working part and a shank. Working part is a tubular body, made slotted in the form of petals with cutting gears on the ends. Working part consists of two coaxial and symmetrically arranged tubular two-petal housings one in the other. Cases are fixed with the help of flanges made on them on the end surface of a tubular shank with an external thread for a driven rotating handle that interacts with an axially transverse cross beam and a helical spring placed inside the shank with radial protrusions on the pushers. Pushers are installed in diametrically made along the entire length of the grooves on the outer surface of the inner tubular body, at the ends facing the cutting gears of which there are cut-off cutters in the form of figured elastic plates with curvilinear ends bent to the center with cutting gears at the ends located in the notches on the end curved surfaces of the petals of the inner case adjacent to the inner curvilinear surfaces of the annular shoulders at the ends of the petals of the outer tubular housing with cutting triple blades.EFFECT: invention provides for obtaining blind annular holes and a separated from the bone tissue hollow core that is integral throughout the depth of drilling in the bone tissue of the neck and the femoral head.1 cl, 12 dwg

Description

The invention relates to medical equipment and can be used in orthopedics and traumatology in the surgical treatment of aseptic necrosis of the femoral head at an early stage of the disease, i.e. until the cartilage layer breaks, according to the method of fenestrating osteotomy, based on bone autoplasty of the necrosis focus with healthy bone tissue in the form of a hollow cylindrical core obtained (cut) from the same proximal part of the neck and femoral head and rotated 180 degrees.

A known design of a reversible annular drill, containing a housing of a zigzag annular profile with external and internal chip discharge grooves and cutting teeth at the intersection of grooves with oppositely directed blades (RF patent No. 2377101, IPC B23B 51/04).

A ring drill is known that has a hollow body with chip discharge grooves and cutting teeth with blades made on both sides of each tooth, which have different front angles in plan and are arranged alternately relative to each other at the same or different height along the axis of the drill (RF patent No. 2287407, IPC B23B 51/04).

Known medical instruments are trephines, which are a single or multi-blade ring drill, consisting of a tubular body with cutting teeth at the end, designed to cut bone fragments during rotational-translational working movement (GOST 25725-89 “Medical Instruments”; www.innomed .net, Orthopedic Instruments, p. 46).

An annular drill (RF patent No. 2460613 dated 09/10/2012, IPC B23B 51/04) containing a tubular body in the form of petals with cutting teeth on the end parts separated by longitudinal slots of variable width and a hollow shank was taken as a prototype.

The main disadvantage inherent in both analogues and the prototype is that when drilling blind holes in the femoral head, it is impossible to ensure the separation in the whole form of the obtained cylindrical core from the bone tissue and cartilage layer without an additional tool and without damage to the latter.

The expected technical results from the invention are:

- the ability to separate from the bone tissue of the femoral head of the obtained cylindrical bone core;

- maintaining the integrity of the bone core;

- performing the core separation operation in a section as close as possible to the cartilaginous layer without damaging it.

The achievement of these results is due to the fact that in the combined annular drill for bone tissue containing the working part, which is a tubular body made slotted in the form of petals with cutting teeth at the ends, and the shank, the working part consists of two coaxially and symmetrically located one in another tubular two-petal cases fixed with flanges made on them on the end surface of the tubular shank with an external thread for a rotary drive handle, inter acting by means of an axially movable transverse traverse and a coil spring located inside the shank, with radial protrusions on the pushers installed in diametrically made along the entire length of the grooves on the outer surface of the inner tubular body, on which the cutting teeth are fixed with cutting cutters in the form of curly elastic plates with curved ends bent to the center of the drill with cutting teeth at the ends located in the cutouts on the end curved surfaces ях of the petals of the inner casing adjacent to the inner curved surfaces of the annular flanges at the ends of the petals of the outer tubular casing with cutting technical teeth.

Between the totality of the claimed features of the invention and the expected technical results obtained using the present invention, there is a causal relationship, namely, that the design of the annular drill detachable cutters located near the top of the drill and made in the form of curly plates with bent and extendable to the center of the drill ends with a curved shape with cutting teeth at the ends, provides separation from the bone tissue of the femoral head and its cartilaginous layer of an integral deleterious core maximum possible length without the use of additional tools.

In FIG. 1 shows a sectional view of a drill design; in FIG. 2 is a view along arrow A in FIG. one; in FIG. 3 is a section AA in FIG. one; in FIG. 4 is a section along BB in FIG. one; in FIG. 5 is a section along BB in FIG. one; in FIG. 6 is a section along G-D in FIG. one; in FIG. 7 - design of a cutting tool; in FIG. 8 is a view along arrow D in FIG. 7; in FIG. 9 is a location diagram of a lesion of bone tissue of the femoral head with necrosis; in FIG. 10 is a diagram of the drilling of the neck and femoral head; in FIG. 11 is a diagram of core segments (branches) from bone tissue and cartilage layer; in FIG. 12 is a form of the obtained bone core and annular blind cavity.

The combined annular drill includes a working part that directly performs shaping of the blind hole and the length of the bone core, and a shank for fixing the drill and transmitting torque.

The working part of the drill (Fig. 1) is a tubular prefabricated slotted construction with an outer diameter of d ₁ and an inner d ₂ , consisting of two-leaf tubular housings located axially symmetrically in one another - inner 1 and outer 2, attached with flanges 3 and 4 to the bottom of the shank 5 (Fig. 2 and 4).

On the outer end surfaces of the petals 6 and 7 (Fig. 3) of the outer tubular body formed by its walls and inner annular beads 8 (Fig. 1), cutting teeth 9 are made, having three blades: one end 10 with a front γ ₁ = 0 and rear α ₁ corners and two lateral - outer 11, located on a diameter of d ₃ , and inner 12, located on a diameter of d ₄ , with front angles γ ₂ = 0 and rear α ₂ (Fig. 2). The difference between the diameters d ₁ and d ₃ , as well as d ₂ and d ₄ , ensures the formation of radial gaps, eliminates the contact of the surfaces of the working part of the drill with bone tissue, reduces the friction moment and the magnitude of the driving torque applied to the shank.

The inner surfaces of the 13 flanges on the petals of the outer tubular body are made curved with a radius of curvature equal to the radius of curvature r of the ends 14 of width k and thickness δ with cutting teeth 15 at the ends of the cutting tools 16 in the form of curly elastic plates (Fig. 7, 8), fixed with visors 17 in the holes of the pushers 18, which are installed in the longitudinal grooves 19, made in one diametrical plane on the outer cylindrical surface of the inner tubular body. The teeth of the cutting incisors are bred alternately in different directions symmetrically with respect to the plane of their location, which increases the width of the annular cut and reduces the magnitude of the friction forces that occur when the surfaces of the ends of the incisors come in contact with bone tissue.

The ends of the pushers located inside the shank are provided with radial visors 20 for interacting with elements of the drive mechanism for their movement.

The end surfaces of the petals 21 and 22 of the inner tubular body (Fig. 3) are curved, paired with the inner curved surfaces of the beads on the petals of the outer tubular body and contain grooves of width k and depth δ for the bent ends of the cutting tools.

The mechanism of movement (extension) of the pushers with cutting tools for separating the cylindrical bone core obtained by drilling consists of a round drive handle 23 mounted with a thread on the outer surface of the shank and interacting with the pusher visors through the ends 25 of the transverse traverse 26 and screw springs 27 (Figs. 1 and 5). To return the pushers to their original position in the stop nut 28, a figured ring 29 freely mounted on the shank is intended with elastic radial tabs 30 located in the slots 31 (Fig. 6).

The bone shavings formed during the drilling of the blind hole and the segments of the obtained core are removed from the cutting zone with the help of cone-shaped dividing lobes of both tubular bodies converging to the shank of the cuts 32.

Using the proposed design of a combined ring drill for surgical treatment of necrosis of the femoral head (Fig. 9) according to the method based on bone autoplasty, is implemented as follows.

In the initial position, the drive round handle 23 is in a position that provides the contact of the transverse beam 26 with the restrictive nut 28 (Fig. 1), and the pushers 18 with the cutters 16 are retracted with the help of the petals 30 of the figured ring 29 into the longitudinal grooves 19 on the inner tubular body 1 .

The blind annular hole in the femoral head is drilled to the maximum possible depth (Fig. 10), which excludes the contact of the cutting teeth with the cartilaginous layer, which is controlled by an electron-optical transducer.

After reaching the required drilling depth, the rotation of the drill is stopped even without removing the drill from the hole obtained, by rotating the handle 23, the traverse 26 is moved, the coil spring 27 is compressed, the pushers 18 are moved and the ends of the cutting cutters 16 are extended from the grooves on the end of the inner tubular body until it contacts the core (Fig. 11). The rotation of the drill is resumed, the torque M _{p is created,} and the process of cutting the cutters into the core body is carried out with the feed forces F created by the elastic deformation energy stored in the spring 27 during compression, until the core is separated from the bone tissue adjacent to the cartilaginous layer (Fig. 12). The maximum value of the cut-in (depth of cut) of the cutting tools in the core body, diameter d _to , is limited by the displacement of the pushers H (Fig. 1), which excludes the mechanical contact of the cutting teeth 15 of the cutting tools 16 with each other. Then the drill along with the integral core is removed from the resulting hole.

Claims (1)

A combined annular drill for blind holes in bone tissue containing a working part, which is a tubular body, made slotted in the form of petals with cutting teeth at the ends, and a shank, characterized in that the working part consists of two tubular coaxially and symmetrically located in each other two-petal cases fixed with flanges made on them on the end surface of a tubular shank with an external thread for a rotary drive handle interacting by means of axially movable transverse traverse and a coil spring located inside the shank, with radial protrusions on the pushers installed in diametrically made along the entire length of the grooves on the outer surface of the inner tubular body, on the ends of the cutting teeth of which are fixed cutters in the form of curly elastic plates with curved ends bent toward the center of the drill with cutting teeth at the ends located in cutouts on the end curved surfaces of the petals of the inner corpus adjacent to the inner curved surfaces of the annular flanges at the ends of the petals of the outer tubular body with cutting three-blade teeth.

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