Despite the accumulated experience in the use of surgical approaches in the treatment of AK in Europe and Russia, such operations have not previously been performed in the Republic of Belarus. In this regard, we found it interesting to share the experience of our own observation of the patient with the successful result of surgical treatment of AK.
Kimmerle’s anomaly (AK) is anatomically characterized by changes in the posterior arch of the atlas, ossification of the oblique atlantooccipital ligament passing over the vertebral groove in the body of the C1 vertebra. In this case, a bony bridge is formed, which turns the groove of the vertebral artery into a vaulted hole through which the artery of the same name passes. According to the International Classification of Diseases of the tenth revision, this pathology is coded as G99.2 – “compression syndrome of the anterior spinal or vertebral artery.” Currently, most researchers attribute AK to one of the variants of anomalies of the craniovertebral region (CVR). The true frequency of AK is unknown, since in most cases it is not clinically manifested or is masked by diagnoses of other diseases.
In 1923. H. Hayek described a bony bridge extending from the posterior edge of the articular process of the atlas to the posterior edge of its arch, which formed an abnormal bony canal. A. Kimmerle was the first to draw attention to the fact that this change can lead to disorders of cerebral circulation. Later, Saupe, Brocher, H. Krayenbuhl and MG Yasargil, when studying radiographs of the cervical spine, found this pathology in patients with vascular disorders in the vertebrobasilar arterial system (VBBA). Since that time, this Atlas anomaly began to be described in the literature under the eponymous term – Kimmerle anomaly.
In the scientific literature, two anatomical variants of AK are traditionally distinguished. The first is characterized by the presence of a bony arch connecting the articular process of the atlas with its posterior arch. In the second version, AK is represented by a bony arch between the articular process of the atlas and its transverse process. This pathology can be unilateral or observed on both sides of the first cervical vertebra. In addition, AK can be complete and incomplete (intermittent). With complete AK, the abnormal bone arch looks like a semicircle, but incomplete when the bone arch is an arcuate outgrowth. According to A.A. Lucika, H. Kratenbuhl, MG Yasargil, the posterior bridge of the atlas over the PA is found only in 10-15.5% of cases. The lateral bridge on spondylograms or spiral computed tomography (SCT) is much less common, as a result of which there are only a few reports about it. When detecting AK, it should be borne in mind that this form of anomaly occurs in 30% of healthy people. At the same time, however, in patients with clinical dysfunction in VBBA (cochleovestibular disorders, ataxia, visual disturbances, etc.) or with myofascial pain in the cervico-occipital region, AK is found only in 7.6% of cases.
The pathogenesis of insufficiency of acute and chronic forms of circulatory disorders in VBBA in the presence of AK appears to be multifactorial. At the same time, it is believed that the development of clinical symptoms caused by this bone anomaly is based on the discrepancy between the nerve elements of the spinal cord and vertebral tissues. These include the occipitalization of the atlant or the remnants of the protoatlant with progressive growth, gradual calcification of the atlantooccipital membrane with microdamages or microbleeds obtained during KVO injuries. It should be borne in mind that microtrauma can be caused during the twisting of the vertebral artery on the lateral mass of the Atlanta in the presence of ponticulus posticus… In another opinion, this pathology is considered as a congenital malformation. One way or another, but as a result of osteo-ligamentous changes in the KVO, PA does not pass in the groove of the atlas arch, as it should be in the norm, but in the hole formed on the one hand by the groove, and on the other, by the ossified atlanto-occipital ligament, which forms a kind of bone bridge. It limits the free movement of the PA and the occipital nerve when moving the head, especially when turning or bending it. However, to date, no direct correlation has been established between the presence of AK and its clinical symptoms. It is generally accepted in the specialized literature that AK acquires clinical significance due to the addition of other etiological factors from other anatomical formations of the KVO.
A.A. Lutsik et al. attach paramount importance to cicatricial degeneration of the artery wall and periarterial tissue due to prolonged traumatization of the PA in the AK region, which leads to the development of intimal damage, early formation of atherosclerotic plaques, narrowing the vessel lumen and / or the formation of its dissection. As a result, sharp movements of the head can provoke the process of destabilization of the hemodynamics of the PA and turn into a source of circulatory disorders in the distal VBBA. Thus, the pathogenesis of hemodynamic disorders in VBBA in AK is etiologically determined by the development of a complex compression-stenosing and (or) irritative effect, as a result of which there is a decrease in volumetric blood flow both along the PA and along the anterior spinal artery.
The clinical manifestations of AK are diverse as they vary from a long asymptomatic course to the formation of a pronounced neurological deficit. With AK, one or both vertebral arteries (PA) and periarterial plexuses, which form the main pathogenetic core of the disease, can be involved in the pathological process. The initial manifestations of AK are characterized by a variety of non-specific neurological symptoms, which include episodes of systemic and (or) non-systemic dizziness, autonomic dysfunction, headaches, transient changes in vision, and neck pain, which creates difficulties in determining the main etiological factor. These patients are followed for a long time with various diagnoses, such as migraine, cephalalgia, tension headache, VSD, etc. from different specialists,