[Variants of clinical course of Dupuytren's contracture and palmar aponeurosis tissue composition in patients of different age groups.]

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.

Morphofunctional Changes in the Tibial and Peroneal Nerves in Shin Lengthening Using High Speed Daily Distraction Technique.

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.

[CHANGES OF THE SUPERFICIAL PERONEAL NERVE IN RELATION TO THE FREQUENCY OF HIGH-FRACTIONAL AUTODISTRACTION IN ORTHOPEDIC LENGTHENING OF THE TIBIA IN DOGS WITH A DAILY RATE OF 3 mm].

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.

Experimental study of the etiology and pathogenesis of sciatic neuropathy under conditions of therapy for ischium fractures.

Surgical (with external fixation device; series I) and conservative (series II) treatment of experimental unilateral transverse fracture of the body and ramus of ischium was carried out in 35 mongrel dogs. Roentgenometry, pathological, and histological studies showed sciatic nerve injury in both series, a complication of the fracture emerging at the moment of primary lesion. Further damage to the nerve due to its compression in an anatomical narrowings with fibrous degenerative tissues and bone fragments under conditions of conservative therapy, tunnel neuropathy, was paralleled by more pronounced destructive changes persisting for one year after the experiment.

[Age-related dynamics of morphometric parameters of tibial nerve in dogs].

The morphometric study of the tibial nerve was performed in 10 mongrel puppies aged 2, 4 and 10-11 months and of 7 adult dogs aged 1-3 years. It was demonstrated that during the process of growth of the animals the numerical density of nerve fibers (NF) and endoneural microvessels decreased, while the proportion of soft-tissue component and the values of all the dimensional characteristics of myelin NF significantly increased. Both the processes of myelin NF differentiation and the appearance of mature large-caliber NF at the age of 10 months resulted in the increase of system heterogeneity accompanied by an increment of entropy. The myelin NF population in adult dogs was characterized by high values of organization and redundancy, and, therefore, it is more deterministic and stable, with greater reliability of information transmission along the nerve trunks as communication channels.