Author contribution: Minasov BSh — study concept and design, data analysis and interpretation, manuscript editing; Yakupov RR — material collection, morphological assessment, primary data processing; Akbashev VN — statistical processing, visualization of results, manuscript writing; Shchekin VS — literature review, morphology data interpretation; Vlasova AO — preparing illustrations, morphometry analysis, manuscript proofreading; Minasov TB — preparing illustrations, discussion; Karimov KK — material collection, clinical follow-up of patients; Akhmeldinova AA — drawing up inclusion/exclusion criteria, coordination of ethical approval.

Compliance with ethical standards: the study was approved by the Ethics Committee of the Bashkir State Medical University (protocol No. 3 dated 12 March 2025) and conducted in accordance with the World Medical Association Declaration of Helsinki (2013 revision). All patients submitted the informed consent to participation in the study.