Microcirculation measured in patients with limb fractures during stimulation of reparative regeneration

Introduction With advances in the study of bone reparative regeneration there are no methods for early detection of impaired consolidation. Methods for stimulating consolidation processes remain an unresolved question. The development of accessible criteria for assessing impaired fracture consolidation and medications for skeletal muscle tissue repair are challenges of orthopedic trauma care.

The objective was to measure microcirculation in patients with uncomplicated fractures to the long bones of the lower limb, impaired consolidation processes, and stimulation of reparative regeneration.

Material and methods The study included 100 young patients with long bone fractures: group 1 (n = 40) with uncomplicated fractures; group 2 (n = 40) with delayed consolidation; group 3 (n = 20) with established delayed consolidation treated with a bioregulator (peptides from the cerebral cortex). The control group (n = 40) consisted of healthy individuals matched for gender and age. Diagnosis, treatment and rehabilitation were produced according to clinical guidelines. Microcirculation index (MI), shunt index (SI), neurogenic (NT) and myogenic (MT) vascular tone, the amplitude of the endothelial, neurogenic, myogenic and respiratory oscillation ranges were measured using laser Doppler flowmetry on the first, second, fifth, tenth and 90th days after the injury. Statistical processing of the findings was performed using the IBM SPSS Statistics Version 25.0 software package.

Results Patients with normal consolidation showed a progressive increase in PM and active oscillation amplitudes in both limbs, a decrease in NT and MT after two days. Patients with delayed consolidation demonstrated a consistently low perfusion index and increased NT and MT in the injured limb (p < 0.05). Patients treated with the neuropeptide drug showed significantly decreased NT and MT in the injured limb, reaching levels comparable to those in normal consolidation (p < 0.05) after 90 days.

Discussion Long-term hypoperfusion, elevated NT and MT in the injured limb, precapillary spasm, and less efficient blood flow redistribution in patients with impaired consolidation were associated with persistent sympathetic activation, which led to persistent vasoconstriction and perfusion restriction, creating unfavorable conditions for angiogenesis and migration of progenitor cells to the area of regenerative bone formation. The mechanism of action of the peptide bioregulator could be explained by activated neuropeptides and neurotrophic factors, optimization of the balance of excitatory and inhibitory amino acids, and GABAergic effects, which ultimately led to the creation of more favorable local conditions for the completion of osteogenesis.

Conclusion Microcirculation in patients with normal bone reparative processes demonstrated early activation of all regulatory mechanisms, decreased HT and MT as early as the fifth day on the injured side, and rapid restoration of perfusion in the healthy limb. Normalized microcirculation was recorded after ten days of surgery. Prolonged hypoperfusion, prolonged precapillary spasm, and less effective blood flow redistribution, high HT and MT were observed in patients with impaired fracture consolidation. Neuropeptide bioregulator had a significant effect on the regulation of microcirculation at the fracture site through reduced HT, MT, and PSH and could be recommended for stimulating reparative regeneration in patients with impaired fracture healing.

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