Object: degenerative diseases of the lumbar spine and their surgical treatment. Aim: to investigate structural and functional changes in the paravertebral muscles in patients with degenerative diseases of the lumbar spine and to study the effect of these changes on the results of surgical treatment. Methods: clinical; computer tomography, biomechanical, ultrasonographic, electromyographic, biochemical, experimental modeling, histological, statistical. Dependence between structural changes in paravertebral muscles, the course of diseases and the results of surgical treatment of patients with degenerative lesions of the lumbar spine (instability of vertebral segments, hernias of intervertebral discs, spondylolisthesis and stenosis spinal canal) has been proved for the first time. Basing on the studies of CT X-ray density of muscle, connective and adipose tissues of the paravertebral muscles of the lumbar spine, a method of studying and assessment of quantitative composition of muscle, connective and adipose tissues was developed. Using the CT data and the developed software, it was discovered for the first time that the percentage of muscle tissue decreases with the age of a person while the connective and adipose tissue increases. It was discovered that patients with degenerative diseases of the lumbar spine have an increased amount of adipose tissue in paravertebral muscles, but first of all in m. erector spine and m. multifidus comparing to healthy people. It has been proved that degenerative changes in paravertebral muscles correlate directly with disorders in other structures of the lumbar spine and progress depending on the diagnosis in the following order: instability of vertebral segments – hernias of intervertebral disks – spondylolisthesis – stenosis of the spinal canal. It was detected that the reduced functioning of paravertebral muscles prior to the treatment reduces even more after it and is slowly restored within three years after the surgical treatment. Ultrasonographic study helped to discover for the first time an increase in echogenicity and a disorder of the echostructure of paravertebral muscles of patients with degenerative diseases of the lumbar spine compared with healthy people while the highest incidence was indicated in cases of stenosis and spondylolisthesis. Scientific knowledge on the morphological features of paravertebral muscles of patients with degenerative diseases of the spine has been supplemented. It has been proved that dystrophic changes in muscle are more evident in m. multifidus of patients with spondylolisthesis and stenosis of the spinal canal. Detected destructive changes in the structure of myofibrils and mitochondria were the most common manifestation in patients with a diagnosis of "stenosis of the spinal canal". Reduced activity of the creatinephosphokinase in serum with a lower content of creatinephosphate in the muscle tissue of patients with various degenerative diseases of the lumbar spine was detected. Positive effect of physical activity on the structural and functional features of paravertebral muscle and the formation of posterior spine fusion in case of using a transpedicular fixation of vertebrae LIV–LV was proved basis of experimental studies. The clinical signs allowing prediction of less satisfactory recovery of the patient's working ability after surgery were detected: older age (over 48 years), longer duration of the disease (more than 6-7 years), longer period of exacerbation (over 2–2,5 months), spondylolisthesis and stenosis of the spinal canal, Osvestery index over 78 % before the surgery. Method of determining the structure of paravertebral muscles by means of CT and the developed software (patent 111269 UA) has been developed. Algorithms allowing prediction of the results of surgical treatment of patients with degenerative diseases of the lumbar spine was developed basing on the evaluation of the preoperative condition of the patient and the structural features of the paravertebral muscles. Clinical and electromyographic researches of the functions of paravertebral muscles helped to determine features of their restoration after surgery caused by degenerative diseases of the lumbar spine, which will provide an opportunity to substantiate the rehabilitation roadmap. Diagnostic value of activity of creatinephosphokinase in serum for evaluation of paravertebral muscles was determined. The developed transpedicular device for fixation of vertebrae of rats and the method of spondylodesis (patent 94502 UA). The results of the study were introduced into the scientific process of the Kharkiv Medical Academy of Postgraduate Education and clinical practice of the Sytenko Institute of Spine and Joint Pathology, KNP "City Clinical Hospital for Emergency and Emergency Medical Care named prof. O.I. Meshchaninov" Kharkiv City Council, KNP "Regional Clinical Traumatological Hospital" of Kharkiv City Council. Тraumatology and Orthopaedics.
