Method for replacing bone diaphyseal defect of humerus with custom antelateral plate in combination with vascularized fibular graft

Abstract

FIELD: traumatology; orthopedics.SUBSTANCE: used to replace a bone diaphyseal defect of the humerus with an individual antelateral plate in combination with a vascularized fibular graft. The essence of the invention lies in a one-stage reconstruction of the diaphyseal defect of the humerus by means of an anatomically contoured anterolateral personalized plate in combination with a vascularized fibular autograft using microsurgical techniques with the use of 3D technologies, including manufacturing on a 3D printer individually for the patient based on Dicom files obtained during CT.EFFECT: method ensures the maximum reduction in the risk of non-union of the fibular bone graft by creating optimal biomechanical conditions that are created when using an individual antelateral plate as part of the reconstruction of an extensive defect in the diaphysis of the humerus.4 cl, 18 dwg, 2 ex

Description

[0001] The invention relates to medicine, namely to orthopedics, traumatology, and can be used for various etiologies of acquired defects of the humerus, including post-traumatic, post-gunshot lesions, as well as defects caused by oncological processes.

[0002] Reconstruction of diaphyseal defects of long tubular bones, including the humerus, is among the most challenging tasks in reconstructive surgery. Most surgeries used to reconstruct segmental bone defects involve lengthy treatment periods, often with unpredictable outcomes, and are subjectively poorly tolerated by patients.

[0003] Despite the enormous progress in surgical techniques, the results of treating bone defects are often unpredictable. In the context of a large number of patients with severe injuries to the musculoskeletal system, this becomes a serious problem, and finding a solution to it is especially urgent, which leads to the need to search for new methods of treating this category of patients and adhere to a personalized approach to treatment.

[0004] There are several treatment methods.

[0005] One of the most reliable and time-tested methods for restoring defects of long tubular bones, particularly the humerus, remains the bilocal compression-distraction osteosynthesis according to Ilizarov, based on the principles of controlled regeneration [1-3]. The principle of the technique is based on the formation of controlled compression-distraction effects in the area of ​​bone fragments and the staged movement of the graft to replace the defect [4]. The use of the Ilizarov bone transport technique allows not only to replace the bone defect, but also to simultaneously correct the deformity of the limb. However, along with undeniable advantages, this method is characterized by a number of significant limitations: it requires long-term wearing of an external fixation apparatus, on average at least 1 year, which is difficult for patients to tolerate, causes severe discomfort, multiple surgical interventions and requires long-term medical monitoring of the patient.

[0006] A modified technology for filling a humeral defect using Ilizarov compression-distraction osteosynthesis and a non-vascularized fibula autograft (patent RU 2743971 C1) is known. In this technology, the bone defect is replaced with an autograft obtained from a fragment of the patient's fibula diaphysis, it is processed externally, giving it a cylindrical shape, transverse canals are drilled in the autograft, incisions are made in the area of ​​the tubular bone diaphysis defect, the proximal end of the autograft is immersed in the medullary canal of the proximal fragment of the tubular bone, and the distal end of the autograft is immersed in the medullary canal of the distal fragment.The tubular bone is fixed in an anatomically correct position with an external fixator. An osteotomy is performed on the longer bone fragment of the tubular bone. The isolated fragment is secured with an external fixator and gradually displaced along the autograft, creating a distraction regenerate until it contacts the opposing fragment of the tubular bone. The external fixator provides compression of the tubular bone fragments (Fig. 1). This approach reduces treatment time, but patients still require regular dynamic monitoring and face the inconvenience associated with prolonged use of an external fixator. It is also worth noting the lack of blood supply to the autograft bone, which increases the risk of nonunion and infectious complications.

[0007] The introduction of modern methods of reconstructive microsurgery into clinical practice, in particular the transplantation of a complex fibular graft, has significantly expanded the possibilities of treating patients with defects of long tubular bones [5].

[0008] Method RU 2617092 C1 is known, which involves harvesting a vascularized fibular graft. This method differs from previously presented methods in that the fibular graft is rotated 180° to telescope the proximal end of the graft into the medullary canal of the distal humeral fragment, and the distal end of the graft into the medullary canal of the proximal humeral fragment. The recipient bed vessels, including the radial artery, are then isolated and anastomosed with the graft vessels in a vein-artery-vein sequence. In this description of the fibular graft fixation method, the osteosynthesis method with a plate and screws is mentioned only in general terms, without specific technical details (Fig. 2).According to the team of authors, this method has a significant drawback: standard fixation structures are not adapted to the individual anatomical features of the patient and the area of ​​the bone defect, which does not allow for achieving complete stability for the formation of bone callus, which, in turn, requires prolonged immobilization of the limb.

[0009] A prior art method, RU 2735994, is known. This method for treating humeral defects involves replacing the humeral defect with free, non-vascularized bone autografts from the fibula and ilium, or with allografts. The isolated fibula autograft is telescopically inserted into the humeral defect area, followed by fixation with a splinting, extra-articular distal humeral plate with angularly stable screws. The next step involves harvesting the autograft from the iliac crest, dividing it into two equal parts, placing spongy-cortical bone autografts along the limb axis, and then mechanically augmenting the bone fragments and grafts with a small, straight plate with angularly stable screws. According to the authors, this method has a number of significant drawbacks.The main drawback is that two plates must be placed to achieve the required stability. This approach requires a more aggressive surgical approach, requiring extensive soft tissue dissection, which negatively impacts vascularization of the surgical site. Furthermore, the lack of an intrinsic blood supply to the bone grafts used is an additional risk factor, increasing the likelihood of nonunion and infectious complications. The extra-articular distal humeral plate, which is difficult to fixate in fractures of the distal humeral shaft, is particularly challenging in the metaphyseal transition zone between the shaft and the supracondylar processes.

[0010] The aim of the authors' work is to identify a highly effective surgical approach for the one-stage reconstruction of an extensive humeral shaft defect. The proposed method minimizes the risk of fibular bone graft nonunion by creating optimal biomechanical conditions using a custom-made antelateral plate during reconstruction of an extensive humeral shaft defect. The stability achieved with this design allows for early patient rehabilitation. Reducing treatment time and subsequent clinical follow-up by minimizing postoperative complications and eliminating the need for repeat surgeries ultimately leads to a significant reduction in the medical and social burden on healthcare facilities.

[0011] The essence of the invention lies in a one-stage reconstruction of the diaphyseal defect of the humerus by means of an anatomically contoured anterolateral personalized plate in combination with a vascularized fibular autograft using microsurgical techniques with the use of 3D technologies, including manufacturing on a 3D printer individually for the patient based on Dicom files obtained during CT.

[0012] The active development of additive manufacturing in medicine creates the preconditions for highly individualized treatment of extensive tubular bone defects [6-9]. 3D technologies make it possible to design various types and kinds of implants, with various fixation methods, and made of different materials.

[0013] Preoperative planning includes the construction of a virtual model of the defect area and the healthy limb based on the patient's CT scan, assessment of the viability of bone and soft tissues with determination of the optimal resection zone (Fig. 10), the possibility of limb length restoration. Determination of the fibula graft with the construction of a template for bone filing (Fig. 11). Modeling of an anatomically contoured personalized antelateral humeral plate (Fig. 3) with all the properties to create the required fixation rigidity, namely, a spoon-shaped configuration of the proximal part of the plate to ensure its tight adaptation to the proximal fragment of the humerus. Fixation in the proximal fragment is performed with locking screws with a diameter of 2.7 to 4.0 mm with a polyaxial direction, the number of which varies depending on the size of the defect (Fig. 4). The screws in the proximal humerus have a polyaxial orientation.The most proximal screws (first-row screws) are placed no higher than the edge of the greater tuberosity to prevent contact with the rotator cuff tendons. They are positioned perpendicular to the plate plane and oriented toward the superior pole of the humeral head. The second-row screws are oriented at an angle of 100-110 degrees to the humeral head and are parallel to each other. The third-row screws have a more acute insertion angle—130-145 degrees relative to the plate axis. If there is intact bone tissue distal to the third row, a fourth row of screws may be inserted; each row is inserted strictly perpendicular to the plate, one screw per row.

[0014] At the transition zone from the proximal fragment to the bone defect, the plate is slightly tapered, following the anatomical contours. The defect area is provided with locking holes for 2.7-3.5 mm screws, the number of which varies from 2 to 4 depending on the defect's extent. The defect area is replaced with a free vascularized fibular autograft that fits tightly to the proximal and distal humeral fragments.

[0015] The graft is fixed with screws into specially designed holes in the monocortical arrangement.

[0016] At the transition area of ​​the bone defect to the distal section, the plate has an anatomically adapted curve at an angle of 35-45 degrees, ensuring its smooth transition from the lateral surface to the anterior part of the distal humeral fragment, adapting to the unique anatomical features of the bone. A key feature of fixation in the distal section is the orientation of the plate end to the medial epicondyle of the humerus. The distal segment is provided with locking holes for 3.0-4.0 mm screws, the number of which is determined by the size of the distal fragment. In the distal humerus, the screws are installed strictly perpendicular (90°) to the plate with bicortical fixation. The three lower screws are oriented in the anteroposterior direction, which is due to the anatomical curvature of the bone. As the transition to the curvature zone occurs, the direction of the screws is adjusted while maintaining their perpendicularity to the plane of the plate (Fig. 5).The plate is tapered at both ends and minimized to ensure a smooth transition from the bone to the plate at their junctions (Fig. 14). At the final stage of modeling, the screw lengths required for fixation are indicated for each mounting hole (Fig. 15).

[0017] The constructed model of the future product, together with the anatomical models of the humerus fragments and the isolated fragment of the fibula (Fig. 12), is made of non-sterilizable plastic using FDM technology for the final evaluation of the design (Fig. 3).

[0018] The plate is manufactured from titanium alloy powder using SLM, and the templates are made from autoclavable photopolymer resin using DLP. A bioactive coating is applied to the plate surface to provide antibacterial protection.

[0019] The method for replacing the diaphyseal bone defect of the humerus using a 3D individual plate and a composite fibular graft is carried out as follows.

[0020] After induction of combined anesthesia, the patient is placed in a supine position with the upper limb to be operated on placed on a surgical table. Careful preoperative markings are performed, followed by standard preparation of the surgical field with antiseptic solutions on the upper limb and the contralateral lower limb (hydraulic dilation).

[0021] After applying a pneumatic tourniquet, an incision is made along the outer surface of the lower leg according to the preoperative markings. The fibula is delicately exposed, with resection of the planned diaphyseal segment. The anterior tibial artery and accompanying vein are also exposed. The surgical wound is temporarily covered with an aseptic dressing.

[0022] A contoured incision is made along the lateral surface of the upper arm, with excision of scar tissue. Bone fragments are explored, with non-viable areas resected. A custom-designed 3D titanium plate is fixed to the proximal and distal fragments using standard techniques. The brachial artery and associated veins are exposed.

[0023] After the recipient site is prepared, the final vascularized bone autograft is harvested and the vascular pedicle is transected. The graft is carefully processed: excess soft tissue is removed, and the vascular bed is flushed with a heparinized solution.

[0024] The fibula bone fragment is precisely adapted to the humeral defect and secured with screws under the plate. Under microscopic magnification (×15), precise end-to-end vascular anastomoses are created between the graft vessels and the brachial artery and veins (Fig. 6).

[0025] After careful hemostasis, the surgical wounds are sutured layer by layer. In the area of ​​graft harvesting, if there is significant soft tissue tension, a split-thickness skin autograft is additionally used to prevent compartment syndrome. Both limbs are immobilized with polymer splints.

[0026] The essence of the invention and the claimed technical result have been verified and are also confirmed by specific clinical cases.

[0027] Clinical Case No. 1

[0028] Patient K, a male born in 1989, sustained a shrapnel wound to the right shoulder. An external fixator was installed, and the wounds were debrided. Radiographs were taken on admission (Fig. 7). After 3 months, the device was removed, and the patient was discharged for outpatient treatment with the aim of healing the wounds from the Shantz rods (Fig. 8). Next, the patient underwent plastic surgery using a non-free thoracodorsal flap to augment the soft tissue component of the shoulder. A cement spacer was placed in the bone defect to restore limb length and maintain space for a fibular graft (Fig. 9). During the preoperative planning of the reconstructive intervention, CT scanning of both upper extremities was performed, based on the results of which a 3D computer model of the right upper extremity was created. The surgeon, together with the design engineer, designed a custom antelateral plate to replace the bone defect of the humerus (Fig. 10-12).The surgery was performed using the technique described above. Postoperative radiographs show restoration of limb length and filling of the bone defect, in accordance with preoperative planning (Fig. 13).

[0029] Clinical Case No. 2

[0030] Patient S., a male born in 1993, sustained a shrapnel wound to the left shoulder. During the previous stages of treatment, a shoulder-forearm external fixation device was installed, and wound debridement was performed. After wound healing, the first stage of humeral bone defect repair was performed using the Masquelet technique with an intramedullary nail. Two months later, the patient was admitted to the traumatology and orthopedics center for further treatment. Upon examination, a fistula tract with moderate serous exudation was visible on the outer surface of the left shoulder at the junction of the upper and middle thirds. Perifocally, the skin was hyperemic with a cyanotic tint and infiltrated. Radiography of the left shoulder was performed in two projections (Fig. 16).In preparation for the final reconstructive procedure, radical excision of the fistula tract was performed, the previously inserted intramedullary nail and bone cement were removed, the cavity was thoroughly debridemented, and a new cement spacer with antibiotic was placed. The soft tissue defect was replaced with a non-free thoracodorsal musculocutaneous flap. A shoulder-forearm external fixation device (AVF) was installed (Fig. 17). After 6 weeks, the device was removed to allow the wounds from the Schanz nails to heal.

[0031] During the preoperative planning stage of the reconstructive procedure, CT scans of both upper extremities were performed, which allowed the creation of a 3D computer model of the left upper extremity. The surgeon, in collaboration with a design engineer, designed a custom anterolateral plate to fill the humeral bone defect (Fig. 18). The surgical procedure was performed using the technique described above. Postoperative radiographs show the bone defect has been filled, in accordance with the preoperative planning.

[0032] The essence of the proposed invention is explained in graphic materials:

[0033] Fig. 1 - method for replacing a defect of the humerus, patent (RU 2743971 C1);

[0034] Fig. 2 - method for replacing a humeral bone defect, patent (RU 2617092 C1), fixation of the fibular transplant with a standard plate and screws;

[0035] Fig. 3 - plastic models of the humerus, individual plate, fibular transplant;

[0036] Fig. 4 - preoperative planning of plate fixation to the proximal fragment of the humerus;

[0037] Fig. 5 - preoperative planning of plate fixation to the distal fragment of the humerus;

[0038] Fig. 6 - creation of vascular anastomoses under microscopic magnification;

[0039] Fig. 7 - patient K., radiographs upon admission to the clinic;

[0040] Fig. 8 - patient K., radiographs after dismantling the AVF;

[0041] Fig. 9 - Patient K., radiographs after replacement of the soft tissue defect of the left shoulder with a non-free thoracodorsal musculocutaneous flap with installation of a cement spacer;

[0042] Fig. 10 - patient K., virtual preoperative planning;

[0043] Fig. 11 - virtual determination of the resection level of the fibula;

[0044] Fig. 12 - patient K., virtual preoperative planning of the final version of surgical treatment;

[0045] Fig. 13 - patient K., radiographs after replacement of the bone diaphyseal defect of the humerus with a custom ante-lateral plate in combination with a vascularized fibular transplant;

[0046] Fig. 14 - narrowing at the edges of the plate;

[0047] Fig. 15 - marking of the lengths of screws provided for fixing for each mounting hole;

[0048] Fig. 16a - X-ray of patient S. at the time of admission - direct projection,

[0049] Fig. 16b - radiograph of patient S. at the time of admission - lateral projection;

[0050] Fig. 17 - X-ray of patient S. after surgery;

[0051] Fig. 18 - X-ray of patient S. after replacement of the bone diaphyseal defect of the humerus with a custom ante-lateral plate in combination with a vascularized fibular graft.

[0052] Sources of information

[0053] 1. Ilizarov G.A. The importance of a complex of optimal mechanical factors in the regenerative process during transosseous osteosynthesis / / Experimental-theoretical and clinical aspects of transosseous osteosynthesis: Proceedings of the All-Union symposium with the participation of foreign specialists. Kurgan, 1984. P. 8-49.

[0054] 2. Barawi O. Treatment of humeral defects using the Ilizarov method. Genius of Orthopedics. 2016;(2):36-39. https: / / doi.org / 10.18019 / 1028-4427-2016-2-36-39.

[0055] 3. Aktuglu, K., Erol, K. & Vahabi, A. Ilizarov bone transport and treatment of critical-sized tibial bone defects: a narrative review. J OrthopTraumatol 20, 22 (2019).

[0056] 4. Shastov A.L., Kononovich N.A., Gorbach E.N. The problem of replacing post-traumatic defects of long bones in domestic traumatological and orthopedic practice (literature review) / / Genius of Orthopedics. 2018. Vol. 24. No. 2. P. 252-257.

[0057] 5. Tkachenko MV, Khominets VV, Ivanov BC Remote result of free skin-bone fibular flap transplantation in a wounded patient with a gunshot defect of the diaphyseal bones of the forearm. Traumatology and Orthopedics of Russia. 2018;24(1): 123-128.

[0058] 6. Hoang D, Perrault D, Stevanovic M. Surgical applications of three-dimensional printing: a review of the current literature. Ann Transl Med 2016;4(23):456.

[0059] 7. Gorbatov PO, Niftullaev AE, Novikov RM Precision personalized implants for replacing bone defects in the treatment of patients with osteooncology / / Modern problems of science and education. - 2016. - No. 6. - P. 247.

[0060] 8. Voloshin V.P., Oshkukov S.A., Galkin A.G. Replacement of an extensive diaphyseal defect of the femur using additive technologies. Bulletin of the Ivanovo Medical Academy 2020;25№2: 51-56.

[0061] 9. Akshaya S, Rowlo РК, Dukle A, Nathanael AJ. Antibacterial Coatings for Titanium Implants: Recent Trends and Future Perspectives. Antibiotics (Basel). 2022 Nov 29;11(12):1719.

Claims

1. A method for replacing a bone diaphyseal defect of the humerus with a custom antelateral plate in combination with a vascularized fibular graft, characterized in that it includes preoperative planning for constructing a virtual model of the defect area and the healthy limb based on a CT scan of the patient, determining the fibular graft with constructing a template for filing the bone, modeling an anatomically contoured custom antelateral plate on the humerus, the proximal part of which has a spoon-shaped configuration adapted to the anatomical contours of the proximal fragment of the humerus, and contains four rows of holes for fixation with locking screws with a diameter of 2.7 to 4.0 mm with a polyaxial direction, the number of which varies depending on the size of the defect;In the area with a bone defect, the plate contains locking holes for screws with a diameter of 2.7-3.5 mm, from 2 to 4 in number, depending on the length of the defect; in the distal segment, the plate contains locking holes for screws with a diameter of 3.0-4.0 mm, the number of which is determined by the size of the distal fragment; in the transition zone from the proximal fragment to the area of ​​​​the bone defect, the plate has a narrowing that follows the anatomical contours; in the transition area from the bone defect to the distal section, the plate is curved at an angle of 35-45 degrees with a transition from the lateral surface to the anterior part of the distal fragment of the humerus; the plate is made on a 3D printer individually for the patient based on DICOM files obtained by CT; Combined anesthesia of the patient is performed, preoperative markings are performed, the surgical field is treated with antiseptic solutions in the projection of the upper limb and contralateral lower limb;The fibula is isolated and the planned diaphyseal segment is resected, including the anterior tibial artery and accompanying vein; an incision is made on the lateral surface of the upper limb with excision of cicatricial tissue, a revision of the bone fragments is performed with resection of non-viable areas; an individual 3D-modeled titanium plate is fixed to the proximal and distal fragments; in the proximal fragment, fixation is performed with locking screws from 2.7 to 4.0 mm in diameter with a polyaxial direction, located in 4 rows, while the screws of the first row are inserted perpendicular to the plane of the plate and oriented towards the upper pole of the humeral head, not higher than the edge of the greater tubercle; the screws of the second row are placed parallel to each other and oriented at an angle of 100-110 degrees to the humeral head; the third row screws are inserted at an angle of 130-145 degrees relative to the plate axis;If there is intact bone tissue distal to the third row, a fourth row of screws is installed, each of which is inserted perpendicularly (at an angle of 90°) to the plane of the plate, one screw per row; the plate is fixed in the distal section, orienting the end of the plate to the medial epicondyle of the humerus, while in the distal section of the humerus, the screws are inserted bicortically and perpendicular to the plate, while the three lower screws are oriented in the anteroposterior direction; the brachial artery and accompanying vein are isolated; after completion of the preparation of the recipient zone, vascularized bone autograft is collected by crossing the vascular pedicle, hydraulic dilation is performed, the bone fragment of the fibula is adapted in the area of ​​the humerus defect and fixed under the plate; end-to-end vascular anastomoses are performed between the vessels of the graft and the brachial artery with veins;perform layer-by-layer suturing of surgical wounds.

2. The method according to paragraph 1, characterized in that the area of ​​collection of the vascularized bone autograft is covered with a split skin autograft.

3. A custom-made antelateral plate for fixation to the proximal and distal fragments of the humerus, characterized in that the proximal part of the plate has a spoon-shaped configuration adapted to the anatomical contours of the proximal fragment of the humerus and contains four rows of holes for fixation with locking screws with a diameter of 2.7 to 4.0 mm, the number of which varies depending on the size of the defect; in the area with a bone defect, the plate contains locking holes for screws with a diameter of 2.7-3.5 mm, in a number of 2 to 4, depending on the length of the defect; in the distal segment, the plate contains locking holes for screws with a diameter of 3.0-4.0 mm, the number of which is determined by the size of the distal fragment; in the transition zone from the proximal fragment to the area of ​​the bone defect, the plate has a narrowing that follows the anatomical contours;In the area of ​​transition from the bone defect to the distal section, the plate is bent at an angle of 35-45 degrees with a transition from the lateral surface to the anterior part of the distal fragment of the humerus; the plate is manufactured on a 3D printer individually for the patient based on DICOM files obtained during CT.

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