We studied different types of the vascular response to direct intraoperative low-frequency electrical stimulation of the sciatic nerve after autoneuroplasty of its tibial portion and analyzed their effects on the limb function recovery. Rats (n=20) underwent 40-min intraoperative electrical stimulation, and hemodynamics in the leg was recorded by photoplethysmography. Functional recovery of the tibial nerve was assessed using a walking path analysis within 12 weeks after surgery. Three types of the vascular response to electrical stimulation were identified: the absence of pronounced hemodynamic changes during the electrostimulation session, hyperkinetic type of hemodynamics, and venous outflow disturbances. In rats demonstrating vascular responses of types I and II during the postoperative period, the functional index of the tibial nerve partially recovered within 12 weeks; in type III, no recovery was observed. It was concluded that the type of hemodynamics during intraoperative electrical stimulation of the damaged nerve subjected to autoneuroplasty affects further restoration of the motor function of the limb.

Introduction World literature data indicate the involvement of inflammatory cells in the pathogenesis of palmar fascial fibromatosis. However, there are no data on possible changes in peripheral blood leukocyte indices in patients with Dupuytren's contracture (DC) in comparison with healthy people. Aim To assess the diagnostic significance of neutrophil-lymphocyte (N/L) and lymphocyte-monocyte (L/M) indices of peripheral blood in patients with CD. Materials and methods 162 medical records of patients admitted for surgical treatment were retrospectively studied. To compare the results of their peripheral blood tests with the norm, anonymous leukocytograms of 110 apparently healthy individuals (control) were used. Results In the group of healthy people and in patients with DC, sexual dimorphism of the absolute content of neutrophils was expressed. In DC males, a statistically significant decrease in the absolute content of lymphocytes (p = 0.05) was found, and in females, a significant increase in the absolute content of monocytes (p = 0.00) compared with the control, while in patients with DC there was no gender-related difference in these indicators, typical for healthy people. N/L ratio was elevated in DC males compared with controls (p = 0.05) and a subgroup of DC females (p = 0.01), but according to the results of ROC analysis, N/L ratio turned out to be diagnostically useless. For the model "L/M – degree of contracture" AUC 0.945, CI 0.918-0.970, p = 0, Se 90.12, Sp 93.21; optimal threshold L/M 3.102. In patients with low L/M (≤ 3.0), the frequency of lesions in both hands and the frequency of grade III-IV contractures are higher by 27.75 % (p = 0.02) and 27.15 % (p = 0.03), respectively than in the high L/M subgroup. Discussion The multidirectional changes in the content of lymphocytes and monocytes in males and females is consistent with the literature data on dual gender-specific ways of regulating the immune system in healthy people and in patients with various diseases. Conclusion The findings of the studied sample of patients show that the lymphocyte-monocyte index is a useful additional laboratory indicator for identifying a risk group for severe fascial fibromatosis. It can be used in clinical practice at no additional cost along with the well-known Dupuytren diathesis criteria to identify a risk group for progression of Dupuytren's contracture.

Introduction World literature data indicate the involvement of mast cells in the pathogenesis of Dupuytren's disease. There is no information on the content of mast cells in the pathologically altered palmar fascia of patients depending on the severity of the contracture. Purpose To study changes in the number, location and degranulation activity of mast cells in the palmar aponeurosis with Dupuytren's contracture of varying severity. Material and methods Histopathological study of surgical material from 52 patients (49 men and 3 women) with Dupuytren's contracture (age range 35-78 years, mean age 59.12 ± 1.25 years) using histomorphometry of epoxy semi-thin sections stained with methylene blue – the main fuchsin. Patients were divided into two groups: group 1 with 1‑2 (n = 16) and group 2 with 3-4 (n = 36) grades of the contracture. Results In group 2, the location of mast cells among contractilely altered collagen fibers of dense connective tissue was recorded more often than in group 1. In group 2, compared with group 1, the following significantly increased: the median number density of mast cells – by 33.79 % (p = 0.0508), the median area of mast cells – by 48.40 % (p = 0.0008) and the index mast cell degranulation – by 94.68 % (p = 0.00000001). Discussion Along with a change in the typical location of mast cells, objective evidence of an increase in their number, activation and degranulation in patients with severe contractures was obtained. Conclusion The obtained results indicate the role of mast cells in the progression of Dupuytren's contracture and expand the understanding of potential therapeutic targets.

ЦЕЛЬ ИССЛЕДОВАНИЯ Выявить особенности повреждений кожи как органа при травматической отслойке покровных тканей тела человека в случае наезда колесом автомобиля. МАТЕРИАЛ И МЕТОДЫ Проанализирован операционный материал от 5 пациентов с отслойкой покровных тканей, оперированных в сроки 1—7 сут после травмы. Возраст пациентов варьировал от 22 до 69 лет: до 30 лет — 2 человека, от 31 до 50 лет — 3 человека. В гистотопографических срезах отслоенных тканей исследовали эпидермис, дерму, подкожную клетчатку и находящиеся в ней артерии, венулы, капилляры, а также поверхностную фасцию бедра. РЕЗУЛЬТАТЫ В сериях поперечных срезов перфорантных артерий встречаются проходимые участки с незначительным количеством тромботических масс в просвете сосудистого русла, а также артерии в состоянии спазма с участками обтурирующего тромбоза. Просветы подкожных вен и вен субдермального сосудистого сплетения тромбированы. В сериях поперечных срезов перфорантных артерий встречаются проходимые участки с незначительным количеством тромботических масс в просвете. Подкожные вены и вены субдермального сосудистого сплетения тромбированы. Выявлены многочисленные микроскопические тканевые щели между слоями эпидермиса, между эпидермисом и дермой, в сосочковом слое дермы, между дермой и подкожной жировой клетчаткой, в подкожной жировой клетчатке, между подкожной жировой клетчаткой и поверхностной фасцией с разрушением субпапиллярного, дермального и субдермального сосудистых сплетений, нарушением иннервации кожи, межклеточных и клеточно-стромальных взаимодействий. ВЫВОД Впервые установлен многоуровневый характер повреждений самой кожи как органа и кровоснабжающих ее сосудистых сплетений при травматической отслойке покровных тканей.

The effect of ageing on the morphofunctional features of nerves and the process of their posttraumatic regeneration has been studied in details. However, it is not known, whether there are differences of the neuroregeneration potential in the young, adult and mature experimental animals.The aim of the study was to evaluate histomorphometrical parameters of the rat sciatic nerve regeneration after cutting and microsurgical suturing depending on their age.Materials and Methods. The study included 15 white laboratory Wistar rats aged 5–6 (young), 8–10 (adult) and 12 months (mature). The sciatic nerve was transected at the level of the middle third of the thigh with microsurgical scissors and sutured with six epi-perineural stitches in the animals. In 4 months the animals were euthanized. Sections of sciatic nerves distal to the levels of sutures were put into araldite, semi-thin slices (0.5–1.0 mkm) were obtained for histomorphometric analysis. Thirteen intact animals were selected as control. Statistical processing was performed using nonparametric methods.Results. The numerical density of endoneural vessels in nerves of operated rats was higher than that in the intact ones, but in mature animals it was significantly lower than in young and adult ones (p<0.001). The numerical density of endoneural cells nuclei in young experimental animals did not differ from that of the intact ones, but in animals from the adult and mature groups it was more than four times higher than in animals from the young group (p<0.001). The numerical density of regenerating myelinated nerve fibers in animals of the young and adult groups did not differ from that of the intact nerve, in animals of the mature group it increased in 2.5 times (p<0.001). The numerical density of degenerating myelinated fibers in the operated animals of experimental groups was higher than in the intact group (two times, six times and 11 times higher, respectively). The diameter distribution of the regenerating myelinated fibers in animals of all groups differed from that of the intact control animals.Conclusions. The data obtained demonstrate a significant decrease in the regenerative potential of Schwann cells and neurons in adult and mature animals compared with the young ones.

The purpose of the study was to determine the capabilities of scanning electron and light microscopy in detecting fungi in surgical material from the patients with Dupuytren's contracture. Material and Methods. The fragments of palmar aponeurosis from 27 patients with Dupuytren's contracture were examined. Paraffin sections stained with hematoxylin-eosin and Periodic Schiff-Methenamine Silver were digitized using AxioScope.A1 microscope (Carl Zeiss Micro Imaging GmbH, Germany). For examination in JSM-840 scanning electron microscope (Jeol, Japan), the samples were dehydrated after fixation, soaked in camphene, dried, and silver sprayed in the IB-6 ionizer (Eiko, Japan). Results. In paraffin sections stained with methenamine-silver, the signs of mycotic microbiota were detected only in 2 (7.4%) of 27 patients, and with the use scanning electron microscopy - in 16 patients (59%). The morphological phenotypes and ultrastructure of intercellular contacts of yeast-like fungi were similar to Candida albicans. In all cases, the budding cells were detected. The destruction of the connective tissue of the palmar aponeurosis was observed in the form of loosening, stratification, and cavities formation (the zones of lysis). Conclusion. The scanning electron microscopy allowed to evaluate the ultrastructure of fungal cells and their interaction with surrounding tissues in the surgical material from the patients with Dupuytren's contracture. A higher percentage of detection of fungal invasion compared to the Periodic Schiff-Methenamine staining was associated with a higher resolution and the ability of a larger area of tissue samples analysis.

Aim– to investigate the patterns of cutaneous microcirculation and their relationship with structural vascular changes in palmar hypoderm in patients with Dupuytren’s disease.Material and methods. In 26 patients with Dupuytren’s contracture aged between 45 and 70 years, the microcirculation of palmar skin was assessed before the planned surgical treatment using ultrasound pulsed Doppler (Minimax-Doppler K, SP Minimax, St. Petersburg, Russia) with a high-frequency sensor of 20 MHz and laser Doppler flowmetry (BLF21, Transonic Systems Inc., USA). The local 3-minute arterial ischemic test was performed in all patients by putting the occlusion cuff on the forearm. Histological analysis of intra-operative tissue specimens was done using light microscopy (Carl Zeiss Primo Star microscope with 3.1 MP UCMOS video camera) MicroCapture Ver 6.6 program was used for data acquisition.Results. The normocirculatory type of hemodynamics (1) was found in 17 % of observations; hyperemic (2) – in 19 %, congestive-spastic (3) – in 42 %, and congestive-static (4) – in 21 %. Histologically type 1 was characterized with initial signs of constrictive arterial remodeling and capillary occlusion, 2 – with marked hyperemia of the microcirculatory bed and diapedesis of blood cells, inflammatory perivascular infiltrates, 3 – with significant narrowing and deformations of lumens in small arteries and hyalinosis of arterioles, 4 – with pronounced polymorphism of capillary loops, significant changes in arteries and veins.Discussion. Hyperemic type of microcirculation reflects high activity of autoimmune inflammation. Congestic-spastic type indicates a significant decrease in the reactivity of precapillary microvessels. Congestic-stasic type is accompanied by the most pronounced constrictive vascular remodeling and denervation of the vascular bed.Conclusion. Dupuytren’s contracture is characterized with predominance of pathological types of microcirculation in palmar skin, which must be taken into account in individualized protocols of additive therapy.

For the purpose of comparative analysis of the clinical course of fascial fibromatosis and tissue composition of the palmar aponeurosis in patients of different age groups сase reports and histological surgical material from 179 Dupuytren's contracture patients treated in 2014-2018 were analyzed. Patients were distributed in age groups: the 1st - younger than 50 years, the 2nd - 50-65 years, the 3rd - over 65 years old. In all groups four variants of Dupuytren's contracture clinical course were noted: swift, fast, benign and deffered. The rates of third-fourth levels of contracture in age groups were 50, 54 and 76% respectively. In groups 2 and 3 the volume per cents of hyperplastic connective tissue and adipocytes in palmar aponeurosis were decreased though body mass indexes were increased in comparison with group 1 (p<0,005). The signs of fat tissue vascularity and perivascular inflammatory infiltration were most pronounced in group 1, in group 3 per cent of vessels with adventitial fibrosis was significantly increased. The obtained data may be used for age-oriented treatment protocols and individual prognosis of fascial fibromatosis recurrence and spread.

Relevance. Dupuytren’s disease (palmar fascial fibromatosis) affects primarily palmar and digital fascia and results in progressive wrist deformity in many patients and often with bilateral involvement. Absence of corresponding data on the patients with severe wrist deformities along with their treatment issues is the ground for targeted research of pathomorphology of advanced disease stages.Purpose of the study — to identify features of ultrastructure of fibromatosis nodules and bands in palmar aponeurosis of patients with Dupuytren’s disease of grade III-IV.Materials and Methods. The authors analyzed medical histories and surgical material of 20 patients aging 42–77 years. Segments from medial portion of pretendinous cord of IV digit were cut for examination under scanning electron microscope (JSM-840, Jeol, Japan).Results. Irrespective of disease history (from 1 to 20 years) fibrbous-fibrillar network and fine cylindrical collagen fibers prevailed in nodules of pretendinous cord which formed semicircular and circular end coils. Empty lacunae, functionally active fibroblasts and close cellular pairs were observed in nodules. Bands differed from nodules by lesser cellularity and less content of fine fibers, orientation of thick fibers mainly along one axis, straightening segments of undulated twisting and separate twisted and tightly interwoven fiber fragments.Conclusion. In Dupuytren’s disease of grade III-IV nodules maintain the role of active contractile centers. Despite relatively small cellularity of pathologically altered tissues there is a potential for progressing, propagation and recurrence of fibromatosis.

Purpose To reveal a possible effect of platelet-rich plasma (PRP) on healing and histostructure of extended fasciocutaneous flaps with axial blood supply Materials and methods A flap based on the superficial inferior epigastric artery (SIEA) and extended to the cranial side according to a template with an area of 18 cm2 was produced in 24 rats. After one-and-half hour femoral artery clipping for temporary ischemia, it was re-perfused and re-planted at the site of SIEA origination. After the operation, six microinjections of platelet-rich plasma (0.1 ml) were performed subdermally that were equally distributed on the flap. Comparison group had injections of saline in the similar number and zones. Control group had flaps without injections. Reference norm sites were skin contralateral areas. Twelve days after the operation, the animals are euthanized. Methods of the study were computer planimetry, histomorphometry, and immunohistochemistry. Results When compared with the control and placebo groups, a more than ten-fold reduction in the area of epidermal defects that were associated with delayed wound healing and necrotic complications was achieved. Polymorphic cell infiltration of the dermis decreased 1.7 times under the conditions of PRP microinjections when compared with the control group. Numerical density of capillaries in the subpapillary plexus doubled, and the number of dermal papillae increased 1.5 times. Discussion Enhancement of capillarization of the superficial skin structures proceeded with inhibition of inflammatory reactions and was probably caused by direct action of growth factors of platelets on endothelial cells. Conclusion PRP microinjections are able to effectively prevent partial necrosis of the extended fasciocutaneous flap based on axial blood supply, accelerate epithelization of the wound along the flap perimeter, and maintain the normal plasticity of the epidermis. There was no significant effect of the drug on the state of deep flap structures (subcutaneous fat and skin appendages).

Цель.Выявление возможного влияния субдермальных инъекций церебролизина на показатели приживления и гистоморфометрические характеристики биологической модели продлённого кожно-фасциального лоскута с осевым кровоснабжением.Материалы и методы.У 29 крыс на основе поверхностной нижней эпигастральной артерии (SIEA) сформирован лоскут, продлённый в краниальную сторону по шаблону площадью 18 см 2 , и после 90-минутного клипирования бедренной артерии у места отхождения SIEA реплантирован.После операции выполнены субдермальные микроинъекции церебролизина (по 0,1 мл) -четыре в межангиосомной зоне (группа Cer 1) и в количестве шести с равномерным распределением по площади лоскута (группа Сer 2).Группы сравнения (Comp 1 и 2) -аналогичные инъекции физиологического раствора.Негативный контроль -лоскуты без инъекций.Условная норма -контралатеральные участки кожи.Через 12 дней после операции животные эвтаназированы.Методы: компьютерная планиметрия, гистоморфометрия, иммуногистохимия.Результаты.В группах Cer 1 и 2 по сравнению с негативным контролем и плацебо достоверно уменьшены относительные площади дефектов эпидермиса, связанные с частичным некрозом лоскута либо замедленным раневым заживлением (2,15 % и 0,23 % против 13,72 % и 11,33 % соответственно).В Cer 1 отмечена гиповаскуляризация гиподермы, истончение эпидермиса и дермы.В Сer 2 по сравнению с контролем и Cer 1 выявлены наибольшие толщина и капилляризация дермы и гиподермы, а также толщина эпидермиса и численная плотность придатков кожи.Обсуждение.Выраженное уменьшение полиморфноклеточной инфильтрации дермы и гиподермы в опытных группах свидетельствует, что стимулированный субдермальными микроинъекциями церебролизина ангиогенез в дерме протекал на фоне торможения воспалительных реакций и был обусловлен прямым действием на эндотелиальные клетки.Вывод.Для оптимизации приживления кожно-фасциальных лоскутов с осевым кровоснабжением в случаях, когда их площадь превышает территорию кровоснабжающей артерии, целесообразно применение микроинъекций церебролизина, равномерно распределённых по всей площади лоскута, включая его ангиосомную и межангиосомную зоны.Ключевые слова: васкуляризованный кожно

A flap on the basis of the superficial inferior epigastric artery (SIEA) extended cranially was formed in 24 rats and replanted after 90-minute femoral artery clipping at the point of SIEA embranchment. Mexidol was injected intramuscularly 30 or 60 minutes before the operation with repeated injection in 2 hours after it (E1 or E2 groups). Control (C) - injections of physiological solution. Methods: ultrasound flowmetry, computer-assisted planimetry of digital images of outer and inner flaps surfaces, histomorphometry, immunohistochemistry. 12 days after surgery in E1 and E2 the per cent area of epidermal defects significantly smaller than in C. The vascular pattern in inter-angiosome zone provide evidence that in E2 the intussusceptive mechanism of angiogenesis was predominant, resulting in increased in comparison with placebo and E2 capillarity of skin vascular plexuses, better liability of skin appendages and hypodermal fat tissue.

The study purpose was to identify histological changes in the peripheral nerves and determine functional significance of subclinical neuropathy in experimental simulation of lower leg fractures. We simulated a tibial shaft fracture in 24 dogs under anesthesia and performed osteosynthesis using an Ilizarov apparatus. After 7, 14, 20, 3537, and 50 days of fixation using the apparatus and 30, 6090, and 120 days after removal of the apparatus, the dogs were euthanised. Electromyography was performed before fracture and within the main phases of the experiment. Samples of the sciatic, peroneal, and tibial nerves were studied histologically using computer morphometry of semithin araldite sections. After 37 days of fixation, the amplitude of M-responses of the tibialis anterior and gastrocnemius muscles decreased by 70% compared to the baseline value, increased after removal of the apparatus, but not restored. There were no sighs of nerve damage by bone fragments or wires. The fraction of degenerating myelinated fibers in the studied nerves was less than 13%. Reorganization of the Remak bundles led to a temporary increase in the number density of nerve fibers. Along with axonal atrophy, the peroneal nerve was characterized by demyelination-remyelination, and the tibial nerve was characterized by hypermyelination. The dynamics of numerical density of endoneurial blood vessels was also different. Despite minor sharp degenerative changes in myelinated fibers, persistent axonal atrophy, demyelination, and retrograde changes were not compensated for up to 120 days after removal of the apparatus. Correlations between the morphometric parameters of myelinated fibers and the M-response amplitude indicated a causal role of subclinical neurological changes in functional outcomes of fractures.

Introduction. There are no studies on vascular pathomorphological changes in persons constituting the risk group on the hand finger traumatic abjunctions and wounds in the available literature, although there is evidence suggesting a significant influence of this factor on the results of revascularizing reconstructive-and-restorative surgeries. Purpose. To reveal and analyze possible pre-existing vascular pathomorphological changes in persons with traumatic finger abjunctions and wounds with a circular saw and milling-machine. Materials and Methods. The authors investigated the operation material from 26 men with open injuries of the hand who engaged in mechanized physical labor and subjected to active or passive smoking using the methods of light microscopy of paraffin and epoxide semi-thin sections. Results. They determined the frequency (50%) and the variants of obliterating arterial involvements of the hand fingers: adaptive neointimal hyperplasia, atherosclerosis, Hammer-syndrome, vasculites. The frequency of pathomorphological changes in vessels is reliably higher in patients above 30 comparing with those at the age from 22 to 30 years. Conclusion. A variety of arterial obliterating involvements of the hand fingers in patients from the risk group on the hand finger abjunctions and wounds evidences about the need to investigate operation material histologically. This approach will allow clarifying the outcome prognosis of revascularizing surgery, as well as the protocol of postoperative management of patients.

Цель. С целью выявления морфологических и гистоморфометрических изменений поверхностного малоберцового нерва при удлинении голени автодистрактором в режиме 1 мм за 60 приемов в течение 12 часов ежесуточно проведены опыты на 12 собаках. Методы. Участки поверхностного малоберцового нерва исследовали через 28 суток дистракции, через 30 суток фиксации голени в аппарате и через месяц после демонтажа аппарата в поперечных аралдитовых полутонких срезах, окрашенных метиленовым синим и основным фуксином. Результаты. Фиброз и повышение клеточности эпиневрия выражены в конце дистракции и фиксации. Выраженная гистологически документированная нейропатия малоберцового нерва (1 опыт из 12 – 8,3 %) выявлена в опыте с облитерацией просветов наиболее крупных эпиневральных артерий и большинства эндоневральных капилляров, а также некробиотическими изменениями части из них. У остальных животных, наряду с увеличением количества сосудистых пучков в эпиневрии, выражена гиперваскуляризация эндоневрия, процентная доля деструктивно изменённых миелиновых волокон (МВ) в исследуемые сроки составила 4,0±0,84 %, 3,3±0,08 % и 2,40±0,55 % соответственно (в интактном контроле – 1,92±0,31 %). Изменения размерных характеристик МВ наиболее выражены на этапе дистракции, распределения МВ по диаметрам – на этапе фиксации. Через 30 дней после снятия аппарата качественные и количественные структурные параметры малоберцового нерва у 11 животных из 12 не отличаются от интактного нерва. Заключение. Риск развития нейропатии малоберцового нерва при изученном способе удлинения голени обусловлен срывом компенсаторно-приспособительных возможностей эпиневрального сосудистого русла. У большинства животных важные для функции проводимости структурные характеристики нервных волокон меняются незначительно и восстанавливаются к концу опыта. Ключевые слова: оперативное удлинение голени, малоберцовый нерв, гистологические исследования.

The experiment was aimed at studying thestructural reorganization of the knee joint synoviumin dogs with modeling of primary osteoarthrosis(MOP) and tibial lengthening (TL). The methods oflight microscopy and histomorphometry of semithinepoxy sections were used to assess the thicknessof synovial surface layer, number of synoviocytelayers, characterize the cells, to measure thenumerical density of vessels, and to define thechanges of the nerves and cell composition of thesubsynovial layer. In MOP-group, thepredominance of type А synoviocytes,hypovascularity and irreversible changes in thenerves of subsynovial sheath were observed. InTL-group, the diversity of type В synoviocyte formsand sizes, hypervascularity of subsynovial layerand signs of its re-innervation were detected. It isconcluded that the hyperplastic synoviopathy ispossible in cases of both hypo- andhypervascularization of subsinovial layer.

A sustained decrease in the M-response amplitudes of m. gastrocnemius and m. tibialis anterior was revealed during experimental orthopedic shin lengthening in dogs using Ilizarov external fixator with an automated drive (distraction 3 mm/day in 120 steps). Transverse contraction of intrafascicular content (by 13.2%), endoneural hypervascularization (by 28-95%), axonal degeneration and myelin decompactization, and destructive changes of no more than 5% fibers were detected in the tibial nerve. In the peroneal nerve, the contraction reached 17.3%. Endoneurium hypovascularization (by 12%), axonal degeneration and demyelinization, and destructive changes of more than 20% fibers were detected in 6 of 9 experiments.

To assess the effect of orthopedic lengthening on proliferative activity of chondrocytes in the articular cartilage, dosed tibial lengthening by 28 mm was performed in 15 dogs at the rate of I mm/day divided into 4 sessions. Experiment time-points - 28 days of distraction, 30 days of fixation in the apparatus and 30 days after the apparatus removal. Methods of light microscopy of paraffin sections, immunohistochemistry, histomorphometry of semithin epoxide sections were used. At the end of distraction, the preferential concentration of Ki-67 marker was detected in the upper layers of the intermediate zone, while focal distribution was noted in the superficial and deep zones of articular cartilage of femoral condyles. Upon completion of lengthening, a stable increase in the number of chondrocytes was noted in the superficial and intermediate zones but not in the deep cartilage zone as com ared with the intact group (n=5).

The experiments on the elongation of the tibia in 18 dogs were performed for 10 days using the Ilizarov apparatus with an automatic drive providing the pace of 3 mm/day for 120 moves (group 1) and 180 moves (group 2). The impact of fractionation of distraction on the structure of the peroneal nerve was estimated. In group 1, perineurium micro-injuries and endoneural blood vessel destruction were detected. In group 2, perineurium preserved its integrity and fine-lamellar structure, endoneural blood vessels were also preserved, however, the decrease in the total area of nerve fiber bundles was more pronounced. Morphometric analysis of the preserved myelinated nerve fibers 60 days after the cessation of distraction indicated less marked axonal atrophy and better myelination in group 2.