RU2845970C1 - Method for temporary isolation with adipose tissue of subfascial anatomical structures in case of deep wounds of shin - Google Patents

Abstract

FIELD: medical science.

SUBSTANCE: invention refers to medicine, namely to surgery. Mechanically fragmented autologous adipose tissue is placed in a pack of single-layer medical gauze. Mechanically fragmented autologous adipose tissue is separated by pressing method into fragments sized to gauze cells. Surface of the subfascial anatomical structures contacting the environment in deep shin wounds is coated with the smaller autologous fatty tissue fragments obtained by pressing. Layer of medical gauze is applied. Thereafter, the larger autologous fat tissue fragments left in the gauze bag are applied.

EFFECT: method allows to temporarily isolate subfascial anatomical structures with adipose tissue in patients with deep shin wounds, create conditions for tissue regeneration in the wound before its plastic closure, ensure wound process control, reduce risk of complications in staged surgical treatment of shin wounds and increase treatment efficiency.

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Description

The invention relates to medicine, namely to surgery, and can be used in the treatment of deep leg wounds.

A shin wound is a soft tissue injury localized between the knee and ankle joints, characterized by a violation of the integrity of the skin caused by mechanical impact, exposure of tissue to extreme temperatures, or impaired blood circulation and innervation (KR "Open shin wound", 2021). Combat wounds of the lower extremities in modern armed conflicts account for 38 to 90% of all soft tissue injuries, half of which are wounds to the shin and ankle. In 30-35% of wounded with soft tissue injury to the shin, the wound process occurs with infectious complications, impaired function, and an increase in the healing period of more than 6 weeks. Non-combat, long-term non-healing wounds of the shin are diagnosed in 1% of the population over 45 years of age, in 8% of the population over 70 years of age, which constitutes one of the largest nosological groups. For these reasons, the relevance of developing new methods for treating leg wounds is constantly growing.

Especially difficult to treat are (both combat and non-combat) leg wounds characterized by damage to the fascia and subfascial anatomical structures. The fascia of the leg is a connective tissue membrane located under the skin and subcutaneous tissue and performing the function of attaching, enclosing and separating muscles, vessels and nerve bundles. Leg wounds characterized by primary (mechanical, thermal) or secondary (inflammatory, ischemic) damage to the proper (deep) fascia and subfascial anatomical structures are usually classified as deep leg wounds. The deep fascia of the leg (DFCL) is an anatomical structure necessary for mechanical protection of the muscles and tendons of the leg, arteries and veins, nerve trunks of the leg, and bones of the leg. Destruction of the leg's own fascia and damage to the underlying muscles, tendons, nerves, vessels, and bones is associated with a significant deterioration in the prognosis of wound treatment and a sharp decrease in the likelihood of maintaining the anatomical integrity of the limb.

Despite the diversity of tissues and organs located under the deep fascia of the leg, they all have a common structural feature - each of the above-mentioned anatomical structures is covered with connective tissue containing fibroelastic soft, collagen-containing, loose and dense fibrous connective tissues. Tissues with similar histological structure that make up the fascial system of the leg include, in addition to the superficial (subcutaneous) and deep (proper) fascia, epineurium, joint capsules, myofascial extensions, periosteum, adventitia and vascular-nerve membranes, muscle aponeuroses, as well as all intramuscular and intermuscular connective tissues, including endo-, peri- and epimysium. Contact with the external environment of the fascial system of vascular, nerve bundles, muscle tissue located under the deep fascia of the leg increases the risk of complications, reduces the functional and cosmetic results of plastic surgery. Thus, one of the main tasks of surgical treatment of deep leg wounds is rapid isolation from the external environment of subfascially located structures, most of which are covered by connective tissue membranes similar in composition and origin. However, in case of extensive wound defects, gunshot wounds, some types of wound infection, and in the general extremely serious condition of the patient, primary wound plastic surgery is contraindicated and subfascial structures cannot be isolated by skin-fascial flaps or split skin grafts. In such clinical cases, temporary isolation of subfascial tissues is necessary.

A method for isolating subfascially located structures is known, in which a sterile elastic transparent radiopaque tube made of a bioinert synthetic polymer - phthalate-free polyvinyl chloride (Angiplast Private Limited, India) is used to isolate tendons [1]. Isolation with a tube is performed as follows: the tube is cut longitudinally along its entire length, then its proximal end is placed with its inner concave surface on the tendon in the surgical wound and shifted along the surface of the tendon in the proximal direction. As a result, the tube with its concave inner surface covers the surface of the tendon by 2/3 of its diameter. The proximal end and the distal end of the tube with the tendon are stitched with a nodal suture. After 4 weeks, the distal blocking suture is removed and, under local anesthesia, the tube is removed through a 1-1.5 cm incision in the projection of the proximal suture.

The method allows to isolate the damaged tendon in the early post-traumatic period, to ensure the fusion of tendon fibers due to the activation of external fibroblasts of the epitenon and fibroblasts of the tendon itself without increasing the risk of adhesion formation when applying an epitendinous suture.

However, the described method has a number of significant disadvantages:

- it involves contact of a foreign body with the wound surface, which is associated with the risk of immune reactions and mechanical tissue damage;

- the rigid shape of the tube ensures the isolation of anatomical structures of only a strictly defined (linear, cylindrical) shape and diameter;

- when the patient’s own regenerative potential is depleted, there is no possibility of stimulating healing by using local regenerative medicine methods in patients with long-term non-healing (chronic) wounds.

A method for temporary covering of subfascial anatomical structures in leg wounds with honey-soaked dressings is known. After primary surgical treatment of the wound, without using additional antiseptics, a strip of gauze soaked in honey is applied to the bottom of the wound. The gauze serves as a matrix that holds the honey to prolong its contact with the wound. A crepe dressing is applied over the gauze. The frequency of dressing changes is twice a day or once a day. The results of using the method in 10 cases of extensive soft tissue wounds and fractures of the leg bones and in 2 cases of soft tissue wounds with damage to the Achilles tendon are described [2]. In all cases, wound healing and complete coverage of the bone and tendons were observed. The authors claim that the effectiveness of the treatment method increased due to the regenerative potential of honey. The duration of complete wound healing from the moment the honey dressing was applied ranged from four to 15 weeks, depending on the size of the wound.

However, the described method has a number of significant disadvantages:

- it involves the long-term presence of an allogeneic biological substance (honey) in the wound, which is associated with the risk of immune reactions and infectious complications;

- there is no possibility of complete or layer-by-layer rapid removal of the active component of the wound dressing (honey) from the wound due to its fluid consistency;

- the potential of honey as a drug for regenerative medicine has been little studied, therefore this type of local therapy/wound isolation cannot be recommended for widespread use.

It is known from numerous previous studies that autologous adipose tissue placed on the wound surface stimulates tissue regeneration and can isolate the wound surface from the external environment. Adipose tissue is the main substrate in modern regenerative surgery due to its composition and comparatively non-traumatic nature of production. The ability of autologous adipose tissue preparations to stimulate wound healing is substantiated, proven, and does not cause significant discussions at present [3, 4, 5].

Before using adipose tissue as a preparation for stimulating wound healing, it is mechanically or enzymatically processed. Depending on the size of the adipose tissue fragments obtained as a result of processing, the preparations are classified as MLT - millitransplant, MKT - microtransplant, ET - emulsified transplant. MLT contains fragments of adipose tissue sized from 1 to 4 mm; MKT - contains fragments sized 1 mm or less; ET consists of fragments sized 400-600 μm or less. It is known that the main effect of local application of adipose tissue is determined by the size of the adipose tissue fragments it contains. A prerequisite for the survival of fat cells is the highest possible surface-to-volume ratio. Fat tissue grafts with a diameter of less than 1 mm (MLT) have exactly this - high in comparison with grafts of a larger diameter - surface/volume ratio, due to which they vascularize faster upon contact with the blood-supplied tissue, and are more likely to engraft under optimal conditions. MLT most effectively perform the function of regeneration and stimulation of the wound process. At the same time, MLT are most sensitive to unfavorable environmental conditions; in the absence of contact with vascularized tissue, small fragments of fat tissue are resorbed faster than large ones. Comparatively large fragments of fat tissue with a diameter of 1-4 mm vascularize more slowly, but are also resorbed more slowly. Thus, under conditions of contact with the external environment, comparatively large fragments of fat tissue are more stable and better adapted to perform the function of isolating the wound from the external environment [5].

The closest to the proposed method of isolating organs and tissues in the wound bottom is the application of stromal-vascular fraction of adipose tissue to the wound surface [3, 6]. The essence of the method is as follows. In patients with wounds on the shin, under local infiltration (Klein's solution) and intravenous anesthesia, vacuum aspiration of 40-60 ml of subcutaneous adipose tissue is performed through a 5 mm skin incision in the lower third of the anterior abdominal wall. After centrifugation according to S. Coleman for three minutes, the lipoaspirate is divided into three layers: the upper one - free triglycerides, the middle one - adipose tissue and the lower one - infiltration solution with blood. After removal of the upper and lower layers, the adipose tissue is evenly distributed over the wound surface in a layer 5-7 mm thick. Application of adipose tissue to the wound surface allows to temporarily isolate the wound from the external environment and stimulate the formation of the granulation layer.

However, this method has significant disadvantages:

- fragments of adipose tissue, ranging in size from fractions of a millimeter to 4-5 mm in diameter, sensitive to varying degrees to contact with the external environment and capable of vascularization and stimulating regeneration to varying degrees, are located in a disordered manner relative to the wound surface; for this reason, there is a high probability of contact with the wound surface of large fragments that are not capable of rapid vascularization, and contact with the external environment of small fragments that are quickly resorbed under such conditions;

- there is no possibility of layer-by-layer rapid removal of the applied fatty tissue from the wound when it becomes infected and dries out.

The aim of the invention is to improve the healing of leg wounds.

The technical result of the method is temporary isolation of subfascially located anatomical structures in patients with deep leg wounds and creation of conditions for tissue regeneration in the wound before its plastic closure, ensuring control over the course of the wound process, reducing the risk of complications during staged surgical treatment of leg wounds and increasing the effectiveness of treatment.

The technical result is achieved by placing mechanically fragmented autologous adipose tissue in a single-layer medical gauze bag and dividing it into fragments by size corresponding to the gauze cells using a squeezing method; smaller fragments of autologous adipose tissue obtained as a result of squeezing are applied to the wound surface, then a layer of medical gauze, onto which larger fragments of autologous adipose tissue remaining in the gauze bag are applied.

The method is used as follows.

For patients with deep extensive wounds of the shin, in the case of contraindications to one-stage closure of the wound of the soft tissues of the shin for the purpose of preparation for reconstructive plastic surgery aimed at partial closure of the wound defect, or preparation of the recipient wound for one-stage closure, transplantation of mechanically fragmented adipose tissue of the patient to the bottom of the wound (lipotransfer) is used according to the proposed method.

The anterior abdominal wall below the navel is used as a donor area for adipose tissue. Before liposuction, an ultrasound of the anterior abdominal wall is performed to determine the thickness of the subcutaneous adipose tissue layer and the condition of the muscular-aponeurotic layer of the abdominal wall in the intervention area, and to exclude the presence of previously undiagnosed abdominal wall hernias. During the operation, after double treatment of the skin with an antiseptic solution, the subcutaneous tissue is infiltrated with Klein's solution (2% lidocaine solution, 0.9% sodium chloride solution, adrenaline solution in standard proportions). A 3-4 mm long skin incision is made to insert a cannula into the subcutaneous adipose tissue layer. To obtain adipose tissue, cannulas 2-4.0 mm in diameter are used with side openings from 1.5 to 4.0 mm in the largest dimension. Aspiration is performed in a gentle mode using syringes. To collect lipoaspirate, sterile syringes with a volume of 20 to 150 ml are used.

Primary processing of the obtained lipoaspirate is performed using one of two methods: 1) sedimentation (settling) at atmospheric pressure for 15 minutes or more, after which the separated lower layer - liquid fraction and large connective tissue fibers and the upper layer (free triglycerides) are removed, and the fragments of adipose tissue remaining in the middle layer of the lipoaspirate are used to isolate the wound; 2) centrifugation using a laboratory centrifuge (1200 g) for 3 minutes, after which the separated lower layer - liquid fraction and large connective tissue fibers and the upper layer (free triglycerides) are removed, and the fragments of adipose tissue remaining in the middle layer of the lipoaspirate are used to isolate the wound.

The lipoaspirate obtained as a result of primary processing is placed in a bag made of single-layer medical gauze. The industry produces medical gauze made of plain weave from warp and weft cotton threads with a surface density of 36 g/ ^m2 . Medical gauze has a number of threads per 10 ^cm2 for the warp and weft of 121 and 71, respectively, and, therefore, has a cell area of 1 ^mm2 [7, 8]. Then the lipoaspirate is filtered by squeezing through the cells of the medical gauze. The part of the lipoaspirate obtained after squeezing is applied directly to the wound surface. This part consists of fragments of adipose tissue with a diameter of 1 mm or less. Then one layer of medical gauze is placed. The remaining part of the lipoaspirate in the gauze bag, consisting of fragments of adipose tissue with a diameter of more than 1 mm, is applied over the gauze layer. Cover with an atraumatic wound dressing. Three to ten days after lipotransfer, the layer of medical gauze together with the upper layer of adipose tissue is removed and the condition of the tissues at the bottom of the wound is monitored. If granulation appears on the wound surface and there are no contraindications, the wound is closed immediately or after a few days using one of the types of skin grafting - a free split graft or local skin-fascial flaps. Thus, during the entire period of time until the final closure of the wound, the subfascial anatomical structures adjacent to the wound defect are isolated from the external environment.

The method is confirmed by the following examples.

Example No. 1. Patient I. was admitted to the clinic in July of this year with the diagnosis of "Multiple shrapnel wounds of the lower extremities with gunshot multi-fragmentary fractures of both shin bones on both sides under the condition of fixation with an external fixation device (EFD), deep soft tissue wound defects of both shins."

Objectively on admission. Right lower limb: external fixation device "Rod military field kit" (EFK KSVP) on the right shin in the shin-foot configuration. In the upper third of the right shin on the inner surface there is a deep wound defect of soft tissues measuring 6 × 3 × 3.5 cm with jagged edges. At the bottom of the wound there is the internal condyle of the tibia with a violation of the integrity of the cortical layer, areas of necrotic subcutaneous fat, bone tissue; the proper fascia of the shin is destroyed. In the middle third of the shin there is a rounded wound defect 8 cm in diameter, 3 cm deep, with jagged edges, at the bottom of the wound there is the internal edge of the tibia, areas of necrotic subcutaneous fat, perimysium of the gastrocnemius muscle.

Left lower limb: AVF KSVP on the left shin. Extensive deep wound defects of soft tissues on the anterior surface of the shin in the middle third measuring 5x3x3 cm with uneven edges, at the bottom of the wound is the diaphysis of the tibia, muscle tissue of the tibialis muscle. In the lower third of the shin there is an irregularly shaped wound defect measuring 4x4x2 cm, at the bottom of the wound are the tendons of the extensors of the foot, the distal metaepiphysis of the tibia lacking periosteum, areas of necrotic subcutaneous fat, tendon fragments partially covered with peritenun.

Upon admission to the clinic, repeated surgical treatment of the wounds was performed, partial reassembly of the AVF, reposition of the tibia fragments on both sides, installation of a vacuum system on the wounds of the lower extremities. The wounds on the left and right shins decreased by 20% of the area, however, at the bottom of the wounds there remained unclosed fragments of the tibia on both sides, and the tendons of the extensors of the foot on the left side.

In order to isolate critically important subfascial structures (bone tissue, tendons), it was decided to perform autologous fat transplantation on the wounds of both shins. Under tumescent anesthesia, adipose tissue was collected from the anterior abdominal wall in a volume of 300 ml of primary lipoaspirate. After centrifugation of the lipoaspirate, the upper and lower layers were removed. The remaining middle layer of the lipoaspirate was placed in a bag made of single-layer medical gauze, filtered (squeezed) through the cells of the medical gauze. Fragments of adipose tissue smaller than 1 mm were filtered, and those larger remained in the gauze bag. The filtered part of the lipoaspirate, smaller than 1 mm in size, with a volume of 100 ml, was placed on the surface of the exposed bone tissue and tendons. Next, one layer of medical gauze is placed on the surface of the lipofiltrate, and on it a part of the lipoaspirate consisting of fragments of fat more than 1 mm in a volume of 150 ml, which remained in the gauze bag. The lipofiltrate is fixed on top with an atraumatic mesh wound covering, it is fixed to the edges of the wound with interrupted sutures. After 7 days, the gauze between the two layers of lipofiltrate is lifted by the edges, removed together with the upper layer of lipofiltrate. The lower layer of lipofiltrate remained on the wound surface. It is covered with a new wound covering. After another 10 days, during the wound revision, active growth of granulation tissue was detected in the wound bottom under the remaining lipofiltrate. Autodermoplasty was performed with a split skin graft over the granulation tissue and viable remnants of the lipofiltrate. Engraftment was 95% of the graft area.

Example No. 2. Patient F. was admitted to the clinic in June of this year with the diagnosis of "Gunshot shrapnel wound of the left shin with a multi-fragmentary fracture of both bones of the left shin, deep soft tissue wound defects of the left shin."

Objectively on admission. Left lower limb: AVF KSVP on the left shin. Deep wound defect of soft tissues on the anterior surface of the shin in the upper and middle thirds, 25x12 cm in size, up to 7 cm in depth, with jagged edges. In the upper and middle thirds, the wound bottom is covered with granulation tissue. In the lower third of the wound, the bottom is the anterior tibialis muscle with the tendon, the long extensor of the toes with the tendon, the fragmented superior extensor retinaculum, and the proximal and distal fragments of the tibia, which are not covered with granulation tissue. In the lower third of the wound, there is a wound channel up to 8 cm deep, which blindly ends in muscle tissue, the discharge from it is moderate, serous-sanguineous.

Repeated surgical treatment of the wound was performed, reposition of the tibia fragments under the EOP on both sides. Plastic surgery of 60% of the wound defect area in the upper and middle third was performed using two skin-fascial rotation flaps. Considering the presence of contraindications to one-stage closure of the lower third of the wound with an infected wound channel, as well as a high risk of drying out and necrosis of the anatomical structures adjacent to the wound defect, a decision was made to temporarily isolate the bone fragments, muscles, and tendons by transplanting autologous adipose tissue onto the residual wound defect using the proposed method. Under tumescent anesthesia, adipose tissue was collected from the anterior abdominal wall in a volume of 120 ml of primary lipoaspirate. After centrifugation of the lipoaspirate, the upper and lower layers were removed. The remaining middle layer of the lipoaspirate was placed in a single-layer medical gauze bag and filtered (squeezed) through the medical gauze, which, in accordance with GOST, has a cell size of 1 ^mm2 [7, 8]. Fragments of adipose tissue smaller than 1 mm were filtered out, and the rest remained in the gauze bag. The filtered portion of the lipoaspirate with a volume of 50 ml was placed on the surface of the exposed bone tissue, tendons, and muscle tissue. Then one layer of medical gauze was placed on the surface of the lipofiltrate, and a portion of the lipoaspirate from the gauze bag was placed on it. The lipofiltrate was fixed on top with an atraumatic wound dressing. After 5 days, the upper layer of the lipoaspirate, consisting of larger fragments, was removed: the gauze between the two layers of the lipofiltrate was lifted by the edges and removed together with the upper layer of the lipofiltrate. Active growth of granulation tissue at the bottom of the wound was detected, no signs of drying or tissue necrosis under the lipofiltrate were found. After another 3 days, plastic surgery of the residual wound defect was performed using a rotational skin-fascial flap. The postoperative period was uneventful.

Thus, the use of the proposed method of temporary isolation of subfascially located anatomical structures in patients with deep leg wounds allows to exclude contact of bones, tendons, muscles and other anatomical structures with the external environment and with foreign bodies in the period before the wound defect is closed with a skin flap or transplant, to create conditions for tissue regeneration in the wound before its plastic closure, to ensure control over the course of the wound process and, ultimately, to reduce the risk of complications in the staged surgical treatment of leg wounds.

Sources of information

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2. Ahmed, A. A., Eltregy, S., & Kandil, M. I. (2022). Honey dressing: a missed way for orthopedic wound care. International orthopedics, 46(11), 2483-2491. https://doi.org/10.1007/s00264-022-05540-9

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7. GOST 9412-93. Medical gauze.

8. Patent No. 2155251 C1 Russian Federation, IPC D03D 25/00, D03D 1/00, D03D 15/00. Bleached cotton medical gauze: No. 99127656/12: declared 24.12.1999: published 27.08.2000 / I.I. Lyubimov, G.A. Goryunova, A.A. Spasov, V.A. Orlova.

Claims (1)

A method for temporary isolation of subfascial anatomical structures with adipose tissue in deep wounds of the shin, including application of mechanically fragmented autologous adipose tissue to the surface of subfascial anatomical structures in contact with the external environment, characterized in that the mechanically fragmented autologous adipose tissue is placed in a package of single-layer medical gauze, separated by squeezing into fragments according to sizes corresponding to the gauze cells, smaller fragments of autologous adipose tissue obtained as a result of squeezing are applied to the wound surface, then a layer of medical gauze, onto which larger fragments of autologous adipose tissue remaining in the gauze package are applied.