[Vertebrobasilar insufficiency caused by extravasal compression of the vertebral artery in the second segment]. / Vertebral'no-bazilyarnaya nedostatochnost', vyzvannaya ekstravazal'noi kompressiei pozvonochnoi arterii vo vtorom segmente.

OBJECTIVE: To develop indications for surgical treatment for positional disorders of blood flow in the vertebral-basilar territory caused by the damage to the V2-V3 segment of the vertebral artery (VA). MATERIAL AND METHODS: One hundred and fourteen patients with systemic and non-systemic dizziness were studied. To assess the state of the VA, blood circulation of the posterior cranial fossa and the base of the brain, ultrasound duplex scanning of blood vessels, selective angiography, MRI, single photon emission computed tomography (SPECT) of the brain and neuropsychological testing were performed. Patients were divided into three groups according to the severity of clinical manifestations of vertebrobasilar insufficiency (VBI). RESULTS: According to ultrasound data, patients of the third group with severe VBI had signs of extravasal compression in 94.3% of cases. In the same group, there was an increase in the systolic-diastolic (S/D) ratio by more than 2.5-3 times, as well as an increase in the resistive index (RI) by more than 1.75 units and pulsation index (PI) more than 2.2 units in V2-V3 segments of VA. In 42.9% of patients of the third group, zones of a decrease in the accumulation of 99mTc-ECD by more than 20% were found in the occipital region during the De Klein test. A direct correlation was established between the clinical manifestations of VBI and a decrease in perfusion during SPECT by 20% or more with the De Klein test (r=0.7). We developed an algorithm for diagnosing high-grade VBI with subsequent identification of a causal relationship with extravasal component effects on VA in the second segment. Indications for surgical intervention were determined in 33 patients with clinical manifestations of blood flow decompensation in the posterior cranial fossa. CONCLUSION: Decreased blood flow velocity in the vertebral or basilar artery by more than 50% with a decrease in PI, breath holding index <0.7 in the hypercapnic test, and no increase in blood flow velocity in a phototest and, in addition, the >20% defect of 99mTc-ECD accumulation in the posterior parts of the brain during SPECT with a De Klein test are the criteria for decompensation of blood flow in the vertebral-basilar territory, requiring surgical correction.

[Topographical and anatomical characteristics of the vertebral artery in the third segment].

Lesions of the vertebral arteries (VAs) are encountered in clinical practice comparatively often. They can be manifested by a wide range of signs and symptoms, including transitory ischaemic attacks in the vertebrobasilar basin, ischaemic strokes (IS), and chronic insufficiency of cerebral circulation with the transition into vascular encephalopathy. Surgical management of VA proximal stenoses requires that the surgeon be highly qualified, because it is associated with a high rate of both intra- and postoperative complications (amounting to 10-15%), including ischaemic strokes, thrombosis of the reconstruction zone, haemorrhage, lymphocele, as well as lesions of thephrenic, recurrent, and sympathetic nerves. Therefore, intervention by means of endovascular techniques is currently the main method of treating proximal stenoses of the VA. Along with it, in the presence of tortuosity and loop formations of the VA, surgical intervention on the first segment (VI) of the VA is the only possible option of treatment thereof However, reconstruction of the distal portion of the VA due to complexity of manipulations in the area involved is the least frequently performed operative intervention. The present work deals with the findings obtained in studying the surgical anatomy of the VA in its third segment (V3). in order to determine the variants of the artery's location and possibilities of surgical treatment in arterial pathology in the first (VI) and second (V2) segments. Autopsy was performed on 15 cervical fragments from patients 30 VAs, respectively) having died from causes not associated with cerebrovascular insufficiency. In the dorsal position of the head, we measured the diameter and length of the VA in the spaces between the first and second cervical vertebrae (M +/- m = 4.6 +/- 1.2 mm and 16.4 +/- 1.7 mm, respectively) and between the first cervical vertebra and the edge of the occipital foramen (M +/- m = 4.4 +/- 1.1 mm and 14.7 +/- 2.2 mm, respectively), the diameter of the vertebral canal in the first cervical vertebra (M +/- m = 5.85 +/- 1.1 mm), the presence of the cerebrospinal branches (in 12%), the distance between the transverse processes of the first and second cervical vertebrae (M +/- m = 15.95 +/- 1.05 mm), as well as the distance between the first cervical vertebra and the edge of the occipital foramen (M +/- m = 13.05 +/- 2.5 mm). The average value of the arterial intima thickness amounted to 68.4 +/- 6.3 microm. Noted was a moderate increase in the arterial wall thickness on the left (485.15 +/- 35.35 microm) as compared with that of the right VA (416.25 +/- 1l3.42 microm) (P = 0.12), at the expense of the middle tunic and adventitia. Hence, the most favourable site for surgical management of the VA pathology is the space between the transverse processes of the first and second cervical vertebrae, in which the diameter of the vertebral canal makes it possible to increase the arterial diameter up to 5 mm, while the length and thickness of the wall--to mobilize the artery without resection of the transverse processes, and to adequately establish an anastomosis in order to determine the variants of the artery's location and possibilities of surgical treatment in arterial pathology in the first (VI) and second (V2) segments. Autopsy was performed on 15 cervical fragments from patients 30 VAs, respectively) having died from causes not associated with cerebrovascular insufficiency. In the dorsal position of the head, we measured the diameter and length of the VA in the spaces between the first and second cervical vertebrae (M +/- m = 4.6 +/- 1.2 mm and 16.4 +/- 1.7 mm, respectively) and between the first cervical vertebra and the edge of the occipital foramen (M +/- m = 4.4 +/- 1.1 mm and 14.7 +/- 2.2 mm, respectively), the diameter of the vertebral canal in the first cervical vertebra (M +/- m = 5.85 +/- 1.1 mm), the presence of the cerebrospinal branches (in 12%), the distance between the transverse processes of the first and second cervical vertebrae (M +/- m = 15.95 +/- 1.05 mm), as well as the distance between the first cervical vertebra and the edge of the occipital foramen (M +/- m = 13.05 +/- 2.5 mm). The average value of the arterial intima thickness amounted to 68.4 +/- 6.3 microm. Noted was a moderate increase in the arterial wall thickness on the left (485.15 +/- 35.35 microm) as compared with that of the right VA (416.25-1l3.42 microm) (P = 0.12), at the expense of the middle tunic and adventitia. Hence, the most favourable site for surgical management of the VA pathology is the space between the transverse processes of the first and second cervical vertebrae, in which the diameter of the vertebral canal makes it possible to increase the arterial diameter up to 5 mm, while the length and thickness of the wall--to mobilize the artery without resection of the transverse processes, and to adequately establish an anastomosis.

Surgical management of vertebrobasilar insufficiency due to pathology of the second-third segments of the vertebral artery.

AIM OF THE STUDY: To determine efficacy of surgical management for vertebrobasilar insufficiency (VBI) associated with pathological passage of the vertebral artery (VA) within the bone canal. MATERIALS AND METHODS: Over the period from 2003 to 2008, a total of twenty-five patients with no effect of conservative therapy during 6 months were subjected to reconstruction of the VA in the 3rd segment. The access to the artery was obtained in a manner similar to that used in reconstruction of the carotid arteries, without intersecting the nodding muscle. All the patients were prior to surgery subjected to neuropsychological testing, extra-and intracranial ultrasonographic study with the positional tests, angiography (NMR or digital subtraction angiography). Doppler ultrasonography of the bypass graft, neuropsychological testing, and angiography by the indications were repeated on postoperative day 7 and 3 months after surgery. RESULTS: In the postoperative period according to the VBI scale and Tinneti scale, we revealed significant improvement of the indices on day 7. The improvement of the cognitive functions was not statistically significant (P >0.05). Transcranial Doppler ultrasonography with the De Kleijn test at baseline revealed that five (21%) patients had a complete arrest of blood circulation along one of the VAs, with a decrease in the blood flow along the basilar artery by more than 50%. In the remaining cases, the difference in the volumetric characteristics of the blood stream along the basilar artery averagely amounted to 42.0 +/- 5.4%. Ultrasonographic study performed both in the short- and long-term postoperative periods (on day 7, at 3 months) did not reveal any significant decrease in the bloodflow along the basilar artery during the positional test. CONCLUSIONS: The external-carotid--vertebral transposition improves the blood circulation in the posterior cranial fossa. An operative intervention performed on the 3rd segment of the vertebral artery removes symptomatology of VBI as early as in the immediate postoperative period. Poor surgical outcomes in hypoplasia of the vertebral artery require further studies aimed at investigating the possibilities of surgical correction of VBI in patients presenting with the vascular pathology concerned.