ASSESSMENT OF EFFICIENCY OF EARLY DECOMPRESSION OF THE SPINAL CORD IN SPINAL INJURY BASED ON MORPHOLOGICAL AND STATISTICAL ANALYSIS © M. Salkov

Study of the morphogenesis processes in tissues of a damaged spinal cord during different periods of trauma, conducting statistical analysis of surgical treatment during acuity and early periods allow evaluating the effectiveness of early decompression. The aim of this research was to study the processes of morphogenesis in the damaged tissues of spinal cord and to evaluate the development of secondary changes due to prolonged compression. Methods : A comparative morphological study of macro- and micro- preparations of 10 corpses. Causes of death were: an ascending edema of a spinal cord - 4, a brain injury - 1, a heavy polytrauma - 2, somatic complications (a thromboembolic disease, a pneumonia) - 3. Results of surgical treatment of 3 groups of patients in the acuity and early postoperative periods were analyzed. A comparative analysis of 180 observations of surgical treatment of patients with spinal cord and cauda equina trauma in the first 3 days, from 3 to 7 days and 7 days to 3 weeks was conducted. Analysis was performed on the American Spinal Injury Association (ASIA) scale. Correlation between morphological and statistical data is performed. Results : On the basis of the morphological analysis, progression of secondary changes of a spinal cord during prolonged compression was determined, which become irreversible on the 7th-8th day. Secondary trauma is less frank after conducting an early decompression. Based on the dynamics analysis of the operations timing and the ASIA scale neurological data dynamics it was established that the effectiveness of surgical treatment in the first two groups (first 6 days) correspond to 70%, and in the third one (between 7 and 21 days) - 10%. Conclusions : Primary spinal cord injury, after prolonged compression, is accompanied by progressive secondary changes and as a result, irreversible changes in the structure and function of the spinal cord. Morphological study helps to explain the results of the statistical analysis and to determine the most effective surgery timing as a whole. Early intervention may prevent the spread of secondary damage


Introduction
Study of the processes of morphogenesis in the tissues of the damaged spinal cord in different periods of injury, and statistical analysis of surgical treatment in acute and early periods allow assessment of efficiency of early decompression.

Literature review
Spinal cord injury has a biphasic course. Primary spinal cord injury occurs at the moment of injury directly, forming an area of contusion and compression of the medulla. Defects of the local vasculature, causing edema and hemorrhage in well-vascularized gray matter and to a lesser extent in the white matter, are observed. Paralysis of neurons involved in motor, sensory and autonomic function occurs in the area of injury. Secondary disaster occurs after the primary injury and leads to damage and death of neural cells. Generally, the progression of the second phase takes place during the first 24-48 hours. Vascular dysfunction, ischemia, glutamatergic excitotoxicity, inflammation and apoptosis are progressed in this period [1][2][3][4][5][6][7][8][9][10][11][12].

Materials and methods
A comparative morphological study of macro-and micro-slides of 10 bodies who died as a result of spinal cord injury in the cervical region was performed. Causes of death were: an ascending edema of a spinal cord -4, a brain injury -1, a heavy polytrauma -2, somatic complications (a thromboembolic disease, a pneumonia) -3. The results of surgical treatment of 3 groups of patients in the acute and early postsurgical periods were analyzed. A comparative analysis of 180 observations of the surgical treatment of patients with spinal cord and cauda equina injury during the first 3 days, from the 3 rd day to the 7 th day and from the 7 th day up to 3 weeks was performed. Analysis was performed based on the American Spinal Injury Association (ASIA) scale. Correlation between morphological and statistical data was performed. All morphological observations showed spinal cord compression. Intravital level of neurological disorders corresponded ASIA -A. Surgery was not performed in three cases. Decompressive laminectomy with dissection and duraplasty was performed in one case. On a section, laminectomy throughout the cervical spine was performed, the spinal cord was examined, macroscopic slides and block preparations of the damaged region of the spinal cord were prepared, then, microscopic studies -colour-ing all micro-slides with Ehrlich hematoxylin -eosin x7, x40 was conducted.

Results
Researches of preparations for 4, 7, 8, 71 days are indicative. In the study of the slides (preparations) of a patient who died on the 4 th day, the tension of the dura mater was revealed. Upon autopsy the brain was edematous, tense, overlaps the dura mater. In the study of macro-slides, an apparent edema was noted, the brain was wet, and the surface was shiny. Foci of brain detritus and areas of intramedullary hemorrhage were revealed. Tension of the dura mater was revealed. Upon autopsy the brain was edematous, tense, overlaps the dura mater. In the study of macro-slides, an apparent edema was noted, the brain was wet, and the surface was shiny. Foci of brain detritus and areas of intramedullary hemorrhage were revealed (Fig. 1).
The study of the slides (preparations) of a patient who died on the 7 th day showed extension of ascending and descending edema. Macroscopically: shine and wetness of the surface were more apparent; medulla is looser and was significantly damaged during manipulation. Petechial hemorrhages are common throughout the edematous tissue, expansion of pericellular and perivascular spaces was observed. Edema of the cells and fibers, disintegration of the trunks, blood stasis with focal largecell infiltration around the vessels, hemolysis of blood in dilated vessels with necrotic changed wall, foci saturated with hemolyzed erythrocytes were apparent. Areas of edema with disintegration of groups of surviving ganglion cells were imaged. The vessels of the pia mater were full-blooded. Neurons were losing their nucleus; structure of the glial tissue was impaired, inflammatory changes were apparent (Fig. 2). Secondary changes are most apparent in the patient who died on the 71 st day. Upon cutting the dura mater, medulla prolapses beyond its edges. However, the edema was less significant than in previous preparations, the medulla had more ordered structure, with no signs of hemorrhage. Vascular pattern was clearly imaged. Research of micro-slides showed different degree of ischemic changes. A significant amount of plasmoblast in surviving ganglion cells associated with the dead neurocytes appears. The cells had increased Nissl's granulosity. Regressive glial changes were significant, reduction in cellular composition. Serous fluid was in pericellular and perivasal spaces. Formation of ischemic cysts was occurred. Diffuse inflammatory infiltration was revealed in the edematous tissue of the meninges (Fig. 3).
Death of the patient, who died on the 8 th day, was due to pulmonary embolism. Within the 1 st day, decompressive laminectomy of three vertebrae (C4-6) with dissection and duraplasty was performed.
In the study of macro-slides, an apparent edema was noted, the brain was wet, and the surface was shiny. Areas of intramedullary hemorrhage were revealed. Microscopically: the medulla had a spongy form, the increase of tissue fluid in interstitial, pericellular and perivasal spaces. Edema is limited to 3 segments; there is no ascending and descending edema. Petechial hemorrhages and areas of necrobiotic changes in the ganglion cells were widespread. Unlike previous studies, anatomical structure of glia, neurons with the presence of nuclei therein was preserved, the cellular composition was preserved best of all, and the edema was limited, indicating less significant secondary changes (Fig. 4).
On the basis of morphological analysis, the progression of secondary changes of the spinal cord during the prolonged compression, which become irreversible on the 7-8 day, was established.
An analysis of 180 patients who were operated in the Regional Clinical Patients who had surgery within the first 3 days showed improvement noted in 69.6 % (56 cases: cervical injury -36; thoracic injury -12; lumbar injury -8).
Patients who had surgery between the 3 rd and the 7 th days showed improvement noted in 61.7 % (34 cases: cervical injury -16; thoracic injury -10; lumbar injury -8).
90 patients had surgery during the period from the 7 th day up to 3 weeks with an improvement noted in 10 % (cervical injury -49; thoracic injury -19; lumbar injury -22). The reasons of late operation: brain injury, heavy polytrauma, somatic complications.
Morphological studies revealed that the secondary injury was less significant after the early decompression and proves low efficiency of decompression after 7-8 days. An analysis of the surgery timing and dynamics of neurological data on the ASIA scale showed that the efficiency of surgical treatment in the first two groups (first 6 days) reached 70 %, in the third group (between the 7 th and the 21 st days) reached 10 % (Fig. 5).

Discussion
Most clinical studies show the high efficiency of early decompression of the spinal cord, which contributes to the improvement of neurological state [13][14][15][16][17].
The best results are observed in the event of a surgery made within the first 24-48 hours [14,15,25,26]. Mirza et al. show improvement in the recovery of neurological disorders in patients that had surgery within the first 72 hours [27].
The study allows justifying the efficiency of early decompression on the basis of morphological and statistical data obtained. With the increase in the pre-surgical period, the number of unsatisfactory results of neurological recovery that increases sharply during decompression after 6 days from the date of injury rises.
It should be mentioned that a degree of the spinal cord compression not necessarily affected the level of development of secondary changes and neurological disorders. This discrepancy can be explained by a vascular factor causing the secondary injury globalization and is a criterion for further study of the issue.

Conclusions
Primary spinal cord injury, after prolonged compression, is accompanied by progressive secondary chang-es and as a result, irreversible changes in the structure and function of the spinal cord. Morphological study helps to explain the results of the statistical analysis and to determine the most effective surgery timing as a whole. Early intervention may prevent the spread of secondary damage.