RU2796438C1 - Method for distraction lengthening of the stump of the metacarpal bone - Google Patents

Abstract

FIELD: medicine; reconstructive surgery of the hand.

SUBSTANCE: invention can be used for distraction lengthening of the metacarpal stump. To implement the method, a hollow cylindrical spacer with a groove is used. The spacer is modeled at the preoperative stage and is made according to a matrix created using 3D printing technologies. After osteotomy, a spacer made of bone cement with an antibiotic with a solid end is put on the proximal end of the distal fragment of the metacarpal bone, an axial wire is inserted intramedullarily, the proximal end of which is bent in a U-shape and inserted into the spacer groove. The spacer is put on with the end with a groove on the proximal fragment of the metacarpal bone. Distraction is performed. After the distraction is completed, the resulting osteogenic capsule is dissected longitudinally, the pin and spacer are removed. The distraction defect is plasty with a cortical-spongy allograft.

EFFECT: method provides conditions for bone graft consolidation and restructuring, reduces the risk of graft resorption, non-union and pathological fracture due to the use of a spacer with an antibiotic and the creation of a tissue reserve at the end of the stumps.

1 cl, 6 dwg, 1 ex

Description

The present invention relates to medicine, namely to reconstructive surgery of the hand, and can be used for distraction lengthening of the metacarpal stump.

To reconstruct a lost finger, distraction elongation of the metacarpal bone stump is often used, which consists in its osteotomy, subsequent gradual axial extension of the distal fragment using an external fixation device, and replacement of the resulting defect with an avascular bone graft. However, in this case, long periods of fusion and restructuring of the graft, its fractures and the formation of a false joint due to insufficient stimulation of bone formation are often noted. Known methods of stimulating bone formation according to the Masquelet method, which consist in the formation of an osteoinductive membrane before bone grafting, by placing a cement spacer in a bone defect with enveloping their ends (Gamal Ayouba, Francois Lemonne, Noufanangue Kanfitine Kombate et al. Insert of nailing associated with the Masquelet technique in recjnstraction of bone defect // J. Orthop.2019 Dec, Vol.31; No. 20; p. 228-231).

A known method of replacing a bone defect, which consists in placing a spacer of bone cement in the defect of the tibia, in performing after 6-8 weeks the second stage of the operation, consisting in osteotomy and moving using the Ilizarov apparatus into the formed osteogenic capsule of the blood-supplied bone graft and performing its osteosynthesis in zone of the formed osteoinductive membrane (Borzunov D.Yu., Mokhovikov D.S., Kolchin S.I., Gorbach E.N. Combined use of non-free bone grafting according to Ilizarov and Masquelet technique in the rehabilitation of patients with acquired bone defects and false joints // Genius of Orthopedics, 2020, Volume 26, No. 4, pp. 532-538).

The method has the following disadvantages:

1) the spacer is placed in an already formed defect, the displacement of the bone segment is performed after the preliminary preparation of the osteoinductive capsule, which prolongs the treatment time;

2) the method is not applicable for end bone defects, in particular the stumps of the metacarpal bones;

3) the spacer is formed by hand, not precision, which makes it impossible to create a spacer (implant) with the specified geometric parameters;

4) the spacer does not allow the distraction of the implant together with the bone fragment, and therefore, the osteogenic capsule is formed only in the area of its location;

5) the spacer does not contain an internal cavity (axial hole), which does not allow it to be inserted into the end of the fragment to be displaced and form an osteogenic capsule that covers the entire graft and overlaps the zone of osteosynthesis of the graft and fragments, as well as to preserve the resulting bone regenerate.

A known method for manufacturing an implant for replacing a defect in the tubular bone (Mitrofanov A.I., Al Delamy O.K., Al Yarns V.S. Replacement of a tibial defect under conditions of an osteoinductive membrane. Orthopedic genius, 2019, volume 25, No. 2, p. 239-242), which consists in manually creating an implant from bone cement with reinforcing it with a Kirschner wire, the ends of which are inserted into the bone marrow canal, moving a fragment of the fibula into the bone defect by the next stage and covering it with the formed osteogenic capsule.

An individual implant made of a bone-substituting substance, made using 3D printing technology, is known to replace defects in long tubular bones (Karyakin N.N., Gorbatov P.O., Novikov A.E., Niftullaev R.M. Surgical treatment of patients with tumors of long tubular bones of the upper extremities using individual implants from bone-replacing material created using 3D printing technologies // Genius of Orthopedics, 2017, vol. 23, no. 3, pp. 323-330).

The disadvantages of the method:

1) the implant does not have a central hole, which does not allow it to be inserted into the bone fragment and form an osteogenic capsule that overlaps the joint area of the bone fragments and closes the graft, as well as stimulate the formation of bone regenerate;

2) there is no possibility of distraction of the spacer together with the bone fragment;

3) the implant cannot be used for end defects of the metacarpal stumps.

As a prototype, the "Method for lengthening the short stump of the metacarpal bone" (RF patent 2120246 dated March 14, 1995) was chosen, which consists in osteotomy of the metacarpal bone stump, axial displacement of its distal fragment on the skin-vascular feeding legs and bone grafting of the resulting defect with a cortical-spongy transplant.

However, the method has the following disadvantages:

1) there is a danger of prolapse of the end of the distal fragment of the metacarpal bone;

2) there are unfavorable conditions for the restructuring and consolidation of the avascular graft, especially in conditions of a scarred bed, which can lead to fractures, infection of the graft and the formation of a false joint;

3) there is no stimulation of bone formation in the zone of contact of the ends of the graft with bone fragments of the metacarpal bone;

4) graft osteosynthesis by the insertion method is not applicable for severe osteoporosis of bone fragments.

The task is to improve the method.

EFFECT: improved conditions for consolidation and restructuring of the bone graft, reduced risk of resorption, non-union and pathological fracture of the graft.

The technical result is achieved by the fact that in the method, including transverse osteotomy of the metacarpal bone, axial movement of the distal fragment using an external fixation device, bone grafting of the distraction defect, osteosynthesis of bone fragments, a supply of tissues is preliminarily created at the end of the stumps; at the stage of preoperative planning, a hollow spacer 1 mm thick and 1.5 cm long is modeled so that the cross section of the spacer corresponds to the cross section of the distracted metacarpal bone at a distance of 0.5 cm from the site of the planned transverse osteotomy; a mold is made on a 3D printer for the subsequent manufacture of a spacer from bone cement with an antibiotic; in the spacer made intraoperatively, a groove 1 cm long and 2 mm wide is made; further, at the elongation stage, the spacer is put on with its solid end on the proximal end of the distal fragment of the metacarpal bone, an axial wire is inserted intramedullarily, the proximal end of which is bent in a U-shape, the short branch of the wire is inserted into the groove of the spacer until it stops with the bending area in the end edge of the closed part of the groove and the proximal end of the distal fragment, put the spacer with the end with a groove on the proximal fragment of the metacarpal bone, distract the distal fragment together with the cement spacer. After the distraction is completed, the resulting osteogenic capsule is dissected longitudinally along the entire length of the distraction defect and the ends of the bone fragments, the pin and spacer are removed, the plastic of the distraction defect is performed with a cortical-spongy allograft, while the distraction regenerates formed are preserved, the formed osteogenic capsule is sutured tightly over the entire length of the cortically - spongy allograft and the area of its contacts with fragments of the metacarpal bones.

The method is illustrated by drawings, where in Fig. 1 shows the hand before surgery; in fig. 2 - hand after transplantation of the skin-fat flap on the ends of the stumps of the metacarpal bones; in fig. 3 is a drawing of the appearance of a bone cement spacer containing an antibiotic; in fig. 4 - hand after the installation of the spacer of the metacarpal bone, passing the intramedullary wire with a U-shaped bent end through the spacer and the distal fragment of the metacarpal bone; in fig. 5 - hand after distraction of the distal fragment of the metacarpal bone together with the spacer; in fig. 6 - bone grafting of a distraction defect with a cortical-spongy graft with covering it and the ends of metacarpal bone fragments with an osteogenic membrane.

The proposed method is carried out as follows.

On the end surface of the stump of the metacarpal bones (Fig. 1) create a supply of tissue at the end of the stump, for this excised scars and transplanted skin-fat flap 1 (Fig. 2). Distraction lengthening of the stumps is performed after the engraftment of the flap. At the stage of preoperative planning, a clinical and radiological diagnosis is established, computed tomography of the damaged hand is performed when scanning with a minimum step (most often no more than 1 mm) of the coordinate table in high-resolution mode with the patient in a stationary position throughout the acquisition of a complete set of tomograms. From the array of tomographic data, information is selected by setting the cutoff level to restore the image of the bone structures of the hand of a certain density. At the stage of preoperative planning, the osteotomy area and the necessary dimensions of the distal metacarpal bone fragment to be displaced and its cross section at the osteotomy level are determined. At the stage of preoperative planning, a hollow spacer 1 mm thick and 1.5 cm long is modeled so that the cross section of the spacer corresponds to the cross section of the distracted metacarpal bone at a distance of 0.5 cm from the site of the planned transverse osteotomy. A mold is made on a 3D printer for the subsequent manufacture of a spacer from bone cement with an antibiotic.

A groove (3) 1 cm long and 2 mm wide is cut in the intraoperatively made spacer (2) (Fig. 3). Perform the first stage of the operation - the lengthening of the metacarpal bone. A crescent-shaped incision is made on the dorsal surface of the metacarpal bone. The extensor tendons are retracted to the side. Allocate the region of the middle third of the metacarpal bone. Using an oscillatory saw, a transverse osteotomy of the metacarpal bone is performed along its middle. The manufactured spacer (2) is put with a solid end on the proximal end of the distal fragment of the metacarpal bone. Through the distal fragment of the metacarpal bone pass intramedullary Kirschner wire (4). The proximal end of the spoke is bent in a U-shape, the short jaw of the spoke is inserted into the groove (3) of the spacer until it stops with the bending area in the end edge of the closed part of the groove and the proximal end of the distal fragment. The distal end of the needle is brought out. The end of the spacer with a groove is put on the proximal fragment of the metacarpal bone. Impose the device for external fixation (Fig. 4). The distal end of the intramedullary pin is fixed to the screw rods (5) of the device. The postoperative wound is sutured. 5 days after the operation, a gradual distraction of the distal fragment is carried out together with a cement spacer, 1 mm per day. After the distraction of the distal fragment of the metacarpal bone is completed, 8 weeks after the operation, the second stage of the operation is performed. At the same time, the external fixation apparatus is removed, an incision is made along the postoperative scar. The extensor tendons are mobilized, taken aside. The formed osteogenic capsule (6) is isolated, which is dissected longitudinally along the entire length of the distraction defect and the ends of the metacarpal bone fragments. The intramedullary wire (4) and the spacer (2) are removed with the distraction regenerate (7) preserved (Fig. 5). The plasty of the distraction defect is performed with a cortical-spongy allograft (8), the transverse dimensions of which do not exceed the outer diameter of the spacer. At the same time, the formed distraction regenerates (7.9) are preserved in the region of the distal and proximal fragments of the metacarpal bone. Perform osteosynthesis of bone fragments and cortical-spongy allograft (8) spokes (Fig. 6). The resulting osteogenic capsule (6) is sutured with interrupted absorbable sutures over the cortical-spongy allograft (8) and its area of contact with fragments of the metacarpal bones. The capsule is covered with extensor tendons. The subcutaneous tissue and skin over the osteogenic capsule are sutured in layers. The hand is fixed with a plaster splint until the bone fragments are consolidated with the graft.

Clinical example

Patient A., aged 22, was admitted to the clinic of the Federal State Budgetary Educational Institution of Higher Education "PIMU" of the Ministry of Health of Russia about the stumps of the first, second, third, fourth fingers at the level of the proximal thirds of the main phalanges, the stump of the fifth finger at the level of the distal third of the main phalanx of the left hand. The patient was injured at work on 10/19/2021 as a result of the fact that the brush got into the rotating mechanism of the machine. Due to crushing of 1-5 fingers, primary surgical treatment of wounds was urgently performed, stumps of all fingers were formed. In the postoperative period, necrosis of skin flaps at the ends of the finger stumps was noted. After performing necrectomy, soft tissue defects were formed measuring 2 cm by 6 cm. Upon admission to the clinic, there were thin, ulcerative scars soldered to the underlying bones on the ends of the stumps of the fingers, and there was no grip of the hand. Previously, the defects on the end surface of the stumps of 2-4 fingers and the first finger were replaced by plasty with the Filatov stem (04/06/2022 and 05/17/2022). Upon re-admission on September 21, 2022, the first stage of distraction lengthening of the stumps of the first and second metacarpal bones was performed in order to restore the function of the bilateral grip of the hand. Before the operation, the necessary dimensions of the cross section of the first and second metacarpal bones at the level of their middle were determined. After that, a spacer of a hollow cylindrical shape was modeled so that its cross section corresponded to the cross section of the distracted metacarpal bone at a distance of 0.5 cm from the site of transverse osteotomy, the spacer length was 1.5 cm, and the wall was 1 mm thick. With the help of additive technologies, a mold was made on a 3D printer and a spacer made of bone cement containing gentamicin was made from it. A half-open through longitudinal rectangular groove 2 mm wide and 1 cm long was sawn through the spacer. During the operation, crescent-shaped incisions were made on the dorsal surface of the first and second metacarpal bones. Performed transverse osteotomy of the metacarpal bones at the level of their middle. The manufactured spacer is put on with a solid end on the proximal end of the distal fragment of the metacarpal bone. A Kirschner wire was passed through the distal fragment of the metacarpal bone and the axial hole of the spacer. The proximal end of the pin is bent in a U-shape, the short jaw of the pin is inserted into the groove of the spacer until it stops with the bending area in the end edge of the closed part of the groove and the proximal end of the distal fragment. The distal end of the spoke is brought out. The second end of the spacer is put on the proximal fragment of the metacarpal bone. A similar intervention was performed on the first metacarpal bone. An external fixation device was applied. The distal ends of the intramedullary wires are fixed to the screw rods of the apparatus. After the operation, a gradual distraction of fragments of the metacarpal bones was performed at a rate of 1 mm per day. The bone fragments were diluted by 35 mm, after which the second stage of distraction lengthening was performed on November 15, 22. At the same time, the external fixation device was removed, an incision was made along the postoperative scar. The extensor tendons are mobilized, set aside. It was noted that a hypervascular osteogenic capsule was formed throughout the distraction defect with a 0.5 cm extension to the ends of the bone fragments. The formed osteogenic capsule was isolated, which was dissected longitudinally throughout the distraction defect and the ends of the metacarpal bone fragments. The capsule throughout its entire length has the same wall thickness of 2 mm. In the region of the proximal end of the distal fragment, there is an endosteally located bone regenerate 1.5 cm long. In the region of the end face of the proximal fragment, there are marginal lamellar bone regenerates 1 cm long and a mature regenerate in the form of a spike with a bone structure. Removed intramedullary wires and spacers. The plasty of the distraction defect was performed with a cortical-spongy allograft, the transverse dimensions of which did not exceed the outer diameter of the spacer, and the length corresponds to the size of the resulting distraction defect. At the same time, the resulting distraction regenerates in the region of the distal and proximal fragments were preserved. Osteosynthesis of bone fragments and grafts with wires was performed. The resulting osteogenic capsule was sutured with interrupted absorbable sutures over the grafts and the area of their contact with fragments of the metacarpal bones. The subcutaneous tissue and skin over the osteogenic capsule were sutured in layers. The hand was fixed with a plaster splint for 4 weeks. The wounds healed by first intention. After the splint is removed, consolidation of bone fragments with grafts is noted according to the type of primary healing. The function of the two-sided grip of the hand has been restored. The ends of the stumps have adequate soft tissue coverage, with no signs of prolapse of the ends of the stumps of the fingers.

Advantages of the method: 1) an osteogenic membrane is formed throughout the entire distraction defect with the transition to the distal and proximal fragments of the metacarpal bone; 2) prevention of infectious complications is achieved, since the spacer contains the antibiotic gentamicin, and the resulting capsule is sutured over the graft, which allows it to be completely isolated from surrounding tissues; 3) endosteal and periosteal bone formation of bone fragments of the metacarpal bone is stimulated, the resulting distraction regenerate is preserved during plasty with a bone graft; 4) the method allows to surround (wrap) the graft with an osteogenic membrane from all sides along its entire length with overlapping of the area of contact between the graft and the fragment of the metacarpal bone, which optimizes the conditions for its consolidation and restructuring and together improves reparative regeneration of bone tissue in the distraction defect; 5) the creation of a preliminary supply of tissues at the end of the stumps ensures the prevention of prolapse of the distal ends of the stumps, improving their blood circulation; 6) the method is applicable for lengthening several metacarpal bones by the required amount.

Claims (1)

A method for distraction lengthening of the metacarpal bone stump, including transverse osteotomy of the metacarpal bone, axial displacement of the distal fragment using an external fixation device, bone grafting of the distraction defect, osteosynthesis of bone fragments, characterized in that a reserve of tissues is preliminarily created at the end of the stump; at the stage of preoperative planning, a hollow spacer 1 mm thick and 1.5 cm long is modeled so that the cross section of the spacer corresponds to the cross section of the distracted metacarpal bone at a distance of 0.5 cm from the site of the planned transverse osteotomy; a mold is made on a 3D printer for the subsequent manufacture of a spacer from bone cement with an antibiotic; in the spacer made intraoperatively, a groove 1 cm long and 2 mm wide is made; further, at the elongation stage, the spacer is put on with its solid end on the proximal end of the distal fragment of the metacarpal bone, an axial wire is inserted intramedullarily, the proximal end of which is bent in a U-shape, the short branch of the wire is inserted into the groove of the spacer until it stops with the bending area in the end edge of the closed part of the groove and the proximal end of the distal fragment, the spacer is put on the proximal fragment of the metacarpal bone with the end with a groove, the distal fragment is distracted together with the cement spacer; after the distraction is completed, the resulting osteogenic capsule is cut longitudinally along the entire length of the distraction defect and the ends of the bone fragments, the pin and spacer are removed, the plastic of the distraction defect is performed with a cortical-spongy allograft, while the distraction regenerates formed are preserved, the formed osteogenic capsule is sutured tightly over the entire length of the graft and the area of its contacts with fragments of metacarpal bones.

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