Версия для печати Shchedrenok V.V., Zakhmatova T.V., Moguchaya O.V.

PATHOLOGY OF VERTEBRAL ARTERY IN TRAUMA OF THE CERVICAL SPINE

North-Western Federal Medical Research Center named after V.A. Almazov,
North-Western Federal Medical University named after I.I. Mechnikov, Saint Petersburg, Russia

Spine and spinal cord injury (SSCI) is an important problem with its high rate, the continuous increasing during the last 20-30 years and involving the working age population. The social and economic significance of such injuries is determined by the significant losses relating to temporary disability, common persistent loss of earning capacity and need for long term and high tech treatment [1, 3-8, 11-16]. Among all SSCI, the proportion of cervical spinal injuries is 35-37 %, with prevailing injuries to the lower cervical spine (2/3 of the injuries). Among patients with polytrauma, cervical spinal injuries are encountered in 2-10 %, with complicated cases in 60 %. Multiple vertebral injuries are identified in 14-60 % [1, 3, 4, 6, 11, 15, 16].
The vertebral artery is characterized by the anatomic and topographic features of its course. These features determine the significant probability of compression: high mobility of the cervical vertebrae, the significant sizes of the reserve spaces in the vertebral artery and the variety of possible compressed agents raging from traumatic hernia of the intervertebral disks and fragments of destructed ligaments to the parts of the bodies and the arcs of the vertebrae [3-7, 11, 16]. The modern magnetic resonance imaging (MRI) and spiral computer tomography (SCT) give the possibility to estimate not only the level, but also features and degrees of injury to the main component of the spinal column – the spine motional segment (SMS), the spinal cord, vessels and the roots of the spinal nerves, the surrounding tissues [6-11]. Currently, the ultrasonic techniques for the vascular system are being widely implemented into medical practice. It is determined by their availability, safety and economic efficiency. The use of color duplex scanning (CDS) provides the possibility for acquisition of sufficiently objective and reliable data about presence or absence of vascular bed pathology, changes in vascular walls and lumena (both inborn and acquired), allows clarifying the features of the course of the arteries, diagnosing stenosis and occlusions and presence of extravasal influence (particularly, influence on the vertebral arteries), calculating the lineal and volumetric components of blood flow velocity at the extra- and intracranial levels [7, 9, 14].
The objective of the study – to carry out the clinical and radial comparisons in diagnostics of vertebral artery pathology in cervical spine injury with use of the optimized protocols of visualization.
The tasks of the study: 1) to perform the comparative analysis of the main orthopedic and neurologic syndromes, the features and degrees of neurologic deficiency and life activity disorders by means of using the standard scales, 2) to conduct the comparative analysis of the results of radial diagnostics (radiology, SCT, MRI, CDS) with estimation of intensity of disk medullary, disk radicular compression syndromes, estimation of changes in blood flow through the vertebral arteries, 3) to determine and to analyse the ultrasonic features of the vertebral artery by means of the quantitative segmental estimation of hemodynamics in combination with assessment of local vertebrogenic influences, systemic hemodynamic significance and summary volumetric blood flow with the aim of description of the ultrasonic syndromes of the vertebral artery, 4) to optimize the system diagnostics of presence or absence of extravasal compression, intensity of irritative factors and intensity of blood flow compensation in the vertebral artery with use of the ultrasonic technique and estimation of the diagnostic information capacity of CDS as compared to the angiographic techniques.

MATERIALS AND METHODS

The study is based on the analysis of the results of the complex examination and the follow-up of 198 patients with traumatic cervical spine injuries who were treated in Saint Petersburg Hospital of Saint Martyr Elisabeth and in Russian Scientific Research Neurosurgery Institute named after A.L. Polenov in 2010-2016. The randomized heterogenic combined sample was used as a method for formation of the sampling population. There were more men (76.3 %) than women, the mean age was 38.9 ± 1. The main causes of SSCI were road traffic accidents (38.4 %), home injury (33.3 %) and diving (19.7 %). Single SSCI was in 121 cases (61.1 %), associated injury – in 77 cases (38.9 %).
The complex clinical and radiologic examination included the analysis of the neurologic and orthopedic status with use of the various standardized objective scales, the X-ray examination of the cervical spine, MRI and/or SCT for the cervical spine and the spinal cord, CDS for the brachiocephalic vessels. Optimization of the protocols for SCT and MRI consisted in the use of morphometry of various parameters of the spine motional segment such as the vertebral artery channel, the facet joints, intervertebral foramena, intervertebral and spinal channels. Optimization of the CDS protocol involved the quantitative estimation of compression and irritation of the vertebral artery and the blood flow analysis.
The X-ray course was conducted with use of the digital X-ray device Easy Diagnost Eleva (Philips) with two X-ray tubes, the telecontrolled digital X-ray diagnostic device KRT-OKO and ARTs-1 (Electron) and the X-ray diagnostic mobile device C-duga RTS 612 (Electron). The radial diagnostics was conducted with two computer tomographic scanners Aquilion 64 and Aquilion 16 Toshiba, Brilliance 6S Philips, 1.5T magnetic resonance scanners Signa Exite GE, Excelerat Vantage Atlas Toshiba, Intera Philips and with the ultrasonic scanners EUB 5500 Hitachi and Vivid S6 GE.
The statistical analysis of the results was conducted with Statistica 7 (StatSoftInc.) for Windows XP. The statistical analysis included the calculation of the extensive coefficients (%), which characterize the relationship between the parts and the integral, mean arithmetic values (M) and errors in mean (m) through the amplitude of the variational series. The possibility of the incorrect rejection of the null hypothesis was tested with χ²-test. The difference was statistically significant with p < 0.05. The diagnostic efficiency of the radial techniques was estimated during the process of the statistical analysis. The information capacity of the diagnostic methods was estimated with the common objective parameters (the operational characteristics): sensitivity, specificity and diagnostic accuracy [2, 6, 9].
All patients gave their written consent according to the requirements of Helsinki declare of World Medical Association.

RESULTS AND DISCUSSION

The table 1 shows the distribution of the patients with cervical spine injuries. Single injuries were in 121 cases (61.1 %) and associated injuries in 77 cases (38.9 %).
The dominating pattern of the injuries (the table 1) and requirement for additional studies (the table 2) were estimated after the preliminary examination. The angiographic examination included SCT-angiography (SCT-AG) and catheter digital angiography (AG).

Table 1. Distribution of patients with cervical spinal injury according to presence of injuries to other anatomical regions (n = 198)

Anatomical region of injury		Number of patients
		Abs.	%
Single injury		121	61.1
Associated injury	Traumatic brain injury (TBI)	53	26.8
	TBI, injuries to chest, pelvis, limbs and other spinal segments	15	7.6
	Injuries to chest, pelvis, limbs and other spinal segments	9	4.5
Total		198	100

Table 2. Distribution of patients according to examination techniques (n = 198)

Examination technique	%
Plain X-ray	69.7
SCT	79.3
MRI	59.6
SCT-AG	36.9
Catheter digital AG	7.6
CDS	100.0

The table 3 shows the distribution of the patients according to the main ultrasonic syndromes. The most common condition was the venous discirculation both in isolated form and in combination with other syndromes.

Table 3. Distribution of patients according to main ultrasonic syndromes (n = 198)

Ultrasonic syndromes	Number of patients
	Абс.	%
Tortuosity with insignificant hemodynamics	22	11.1
Deformation with local hemodynamic significance	48	29.3
Extravasal compression	16	9.1
Irritative influence	53	25.8
Dissection and thrombosis	20	10.1
Extravasal influence at level of V3-segment	27	8.6
Venous discirculation	126	63.6

The complex spiral computer tomography included the examination of several regions (the brain, facial bones, the cervical and thoracolumbar spine, the chest organs, pelvic bones) and was conducted for 23.2 % of the patients with abdominal SCT in 7.1 %. The low traumatic potential was provided with the single-moment positioning the patients on the tomographic table, regardless of the number of the examined regions.
The surgical interventions (the table 4) were conducted for 139 patients (70.2 %), with anterior decompressive stabilizing surgery and anterior microdiscectomy with spinal stabilization (56.8 %) in most cases (79 cases).

Table 4. Distribution of patients according to patterns of surgical interventions

Character of surgical intervention	Number of cases
	Abs.	%
Anterior decompressive stabilizing surgery	59	42.4
Anterior microdiscectomy with spinal stabilization	20	14.4
Anterior microdiscectomy with spinal stabilization	3	2.2
Anterior decompression, posterior spondylodesis	13	9.4
Posterior spondylodesis	25	18
Open reduction of dislocation fracture	14	10
Occipitospondylodesis	5	3.6
Total	139	100

The table 5 shows the diagnostic information capacity of the various methods, where Se – sensitivity, Sp – specificity, Ac – accuracy. The results of the study have shown the high information capacity of CDS, with similar values as compared to the angiographic techniques.

Table 5. The indices of information efficiency of diagnostic techniques for  spinal cord injury (n = 198)

Examination technique	Information capacity (%)
	Ac	Se	Sp
X-ray imaging	58.2*	63.7*	55.6*
SCT	91.5	93.8	89.1
MRI	62.7*	68.5*	57.3*
SCT-AG, AG	89.4	91.3	87.4
CDS	86.9	88.3	85.3

Note: * - statistically significant differences as compared to SCTТ

10 patients died as result of SSCI. The mortality was 5.1 %. The causes of death were ascendant spinal cord edema (4 cases), respiratory insufficiency (5) and cardiovascular insufficiency (1).
The optimization of the examination of the patients with morphometry during SCT, MRI and CDS provides the data for multi-level estimation of the bone and soft tissue structures of SMS (including the vertebral artery channel) and of the vascular and neural structures including the vertebral artery. It improves the short term and long term results of surgery. The good (significant improvement) and fine (full disappearance of the symptoms) results were achieved in 54.5 % and 65.2 % correspondingly (p = 0.00001).

DISCUSSION

Computer tomography is still of great importance despite of development of magnetic resonance imaging. It is determined by more wide availability and higher economic efficiency of SCT as compared to MRI, absence of artefacts from metal constructs, more sparing conditions for a patient which are associated with lower time of scanning that is especially important for agitated patients with traumatic brain injury and polytrauma. The literature findings show the higher information capacity owing to the engineering and technical improvements in multi-slice SCT that allow intensifying the spatial and time resolution during examination of bone structures [10]. SSCI with ultrasonic syndromes of the vertebral artery pathology, even in case of absent neurological disorders, was considered as a complicated injury owing to the fact that the vertebral artery lesion shows the rude changes in SMS. It is necessary to note that in some cases radiography and SCT in “bone mode” can visualize injuries in view of fractures and fissures with projection transecting the vertebral artery channel [7].
The uniform clinical and orthopedic neurological syndrome appears in different injuries to the cervical spine. It is determined by deformation and destruction of SMS structures including the vertebral artery channel. The ultrasonic changes in the course and hemodynamics of the vertebral artery were observed in 93.9 % of the patients with SSCI. Development of local hemodynamically significant vertebrogenic influences on the vertebral artery is directly related to the degree of decrease in the cross-sectional area of its channel (p = 0.04). The relationships between neurological symptoms, intensity of pain syndrome and limitations in vital activity were not found after use of the standard scales and estimation of the ultrasonic syndromes (p = 0.06; p = 0.2 and p = 0.95 correspondingly). It allows making the conclusion that the main clinical symptoms do not depend on changes in blood flow in the vertebral artery and are not determined by decrease in blood flow in the vertebral-basilar basin.
It was found that the main ultrasonic syndromes indicating the vertebral artery pathology were deformation of the course with local hemodynamic significance, compression with systemic deficiency of blood flow, irritative influences, dissection and thrombosis, extravasal influences at the level of V3-segment and venous discirculation in the vertebral-basilar basin. The use of CDS allows clear clarification of the level, characteristics and intensity of pathologic changes of the vertebral artery and need for additional contrast methods of the examination including the techniques with radiation load.
Optimization of the protocol of CDS consisted in segmental quantitative qualimetry of changes in the vertebral artery with estimation of the indices of compression and irritation of the vertebral artery and compensation of blood flow in the artery. It significantly increased the diagnostic information capacity of the technique: accuracy was 86.9 %, sensitivity – 88.3 %, specificity – 85.3 %.

CONCLUSION

1. Color duplex scanning should be considered as the obligatory technique for the cervical spine injuries which is the most available, safe, highly informative and is able to determine the characteristics, location and severity of lesion of the vertebral arteries.
2. Cervical spine injuries cause the uniform clinical, orthopedic and neurological syndrome, which is determined by deformation or destruction of the structures of the spinal motion segment including the vertebral artery channel. Development of local hemodynamically significant vertebrogenic influences on the vertebral artery is directly related to the degree of stenosis, which is calculated on the basis of morphometry of cross sectional area of its channel.
3. During planning the volume of surgical treatment for spine and spinal cord injury one should consider the characteristics (dissection, compression, thrombosis) and severity of injuries to the vertebral arteries; according to ultrasonic examination, the values of such injuries are closely associated with a type of a spinal fracture.
4. Optimization of the protocol of CDS examination should consist in segmental quantitative estimation of changes in blood flow in the vertebral artery with assessment of the indices of compression, irritation and compensation of blood flow that significantly increases the diagnostic efficiency of the technique.

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