Have cranio-vertebral junction anomalies been overlooked as a cause of vertebro-basilar insufficiency?

Dynamic imaging of the craniovertebral junction is mandatory in patients with posterior circulation strokes

INTRODUCTION

The course of the vertebral artery after exiting from the C1 foramen transversarium and prior to entering the dura lends itself to compression in C1-2 instability. However, atlantoaxial dislocation presenting with vertebrobasilar insufficiency and posterior circulation stroke (PCS) is rare.

METHODS

In this retrospective study, we identified 96 patients with PCS who had complete radiological data. Ten (10.4%) patients had craniovertebral junction (CVJ) anomalies, of which six underwent surgery and four were managed conservatively. The clinical and functional outcomes were measured in the two groups.

RESULTS

Left-sided strokes were seen in 7/10 patients, the majority of whom had left dominant vertebral arteries. The mean age at presentation in those with CVJ anomalies was 27.2 ± 12.8 years that was significantly lower than those without CVJ anomalies, 52.2 ± 14.5 years (p ≤ 0.001). The etiologies of PCS in those < 50 years were CVJ anomalies (30%), atherosclerosis (30%) and vasculitis (27%); however, the overwhelming majority of strokes in the > 50 year age group was atherosclerosis (91%). Postoperatively, there were no recurrent strokes in the operated patients, who also obtained significant clinical improvement on the modified Rankin Scale, Nurick Scale and modified McCormick Scale as compared to those who did not undergo surgery.

CONCLUSION

Early diagnosis and surgical treatment of CVJ instability prevent recurrent strokes and improve outcomes in patients with PCS. Physicians and spine surgeons need to be sensitized regarding CVJ anomalies as a cause of PCS enabling early diagnosis with dynamic imaging particularly in the younger age group. These slides can be retrieved under Electronic Supplementary Material.

Medullary Infarction Leading to Locked-In Syndrome Following Lumbar Puncture in a Patient with Basilar Invagination

BACKGROUND

Lumbar puncture is a common procedure that can be safely performed in most patients. Certain populations may have increased risk for complications following lumbar puncture, but the significance of basilar invagination is often underappreciated.

CASE DESCRIPTION

A 45-year-old woman with basilar invagination received multiple lumbar punctures in the workup of acute meningitis. Preprocedural computed tomography was obtained. Following lumbar puncture, the patient developed locked-in syndrome. Magnetic resonance imaging obtained several days later demonstrated severe compression and infarction of the medulla and inferior cerebellum by the odontoid process and ectopic cerebellar tonsils. The patient was transferred but at this point, surgical decompression was not possible. She did not regain significant neurologic function.

CONCLUSIONS

Basilar invagination is a risk factor for devastating neurologic complications following lumbar puncture. Awareness of this complication and prompt recognition of its occurrence may prevent future morbidity of lumbar puncture in patients with basilar invagination.

Rotational vertebral artery occlusion in a patient with basilar invagination

Basilar invagination (BI) is a congenital or acquired craniovertebral junction (CVJ) anomaly with odontoid process superiorly migrating into the foramen magnum. Compression of neural structures is the most relevant complication of BI. However BI is also a rare cause of ischemic stroke. In this case we reported a 30-year-old female with BI who developed recurrent ischemic stroke in posterior circulation. Before the onset of ischemic stroke, she didn't present neck pain or clinical signs of lower cranial nerve dysfunction, brainstem compression or transient ischemic attack. At first she suffered from sudden onset of left-sided hemidysesthesia. Magnetic resonance imaging from a local hospital revealed an acute infarction in the right thalamus. Cerebral MR angiography was unremarkable at that time. The tip of the odontoid process had protruded into the foramen magnum and could be observed at the level of the lower medulla, but unfortunately it was ignored by the clinicians and the radiologists. She was given antiplatelet therapy and the sensory disturbance disappeared gradually. However she experienced a recurrence in the pontine and midbrain region 2 months later. At this time she was transferred to our hospital, and reconstructed computed tomography of cervical spine demonstrated basilar invagination, atlanto-axial dislocation, and atlanto-occipital assimilation. Computed tomographic angiography (CTA) revealed a dominant right vertebral artery (VA) and a redundant loop in its third segment. Dynamic cerebral angiogram demonstrated that the patient had a Bow Hunter's type phenomenon, with dynamic occlusion of the right dominant VA during contralateral head turn. This case highlighted the necessary of hemodynamic evaluation in asymptomatic basilar invagination.

Complications of transoral and transnasal odontoidectomy: a comprehensive review

BACKGROUND

Odontoidectomy has been considered an effective way to treat anterior cervicomedullary compression in patients presenting with craniocervical joint anomalies. The transoral and transnasal routes have been described for anterior decompression surgery. However, to date, a comprehensive review of the complications from this procedure is lacking in the extant medical literature. Therefore, herein, we review this specific literature as a resource for surgeons.

METHODS

A comprehensive review of the literature via online search engines was performed.

CONCLUSION

The most reported complications for odontoidectomy are CSF leakage, postoperative craniocervical instability, velopharyngeal insufficiency, wound dehiscence, pulmonary issues, meningitis, and death. To our knowledge, this is the first comprehensive review of complications of odontoidectomy. Increased awareness of the more common complications associated with this procedure may help in the care of patients in the future.

Profile of patients with craniovertebral junction anomalies with posterior circulation strokes

BACKGROUND

Craniovertebral junction (CVJ) anomalies are rare and treatable risk factors for posterior circulation strokes (PCSs). Most of the literature comprises case reports and from varied specialities.

METHODS

Chart review of patients with PCS with CVJ anomalies admitted in a single tertiary stroke care unit. We describe their clinical profile, investigative findings, and therapeutic outcomes.

RESULTS

We saw 7 patients (6 males, mean age 20.1 ± 12.0 years), all previously undiagnosed during the 6-year period. Three patients had a combination of atlantoaxial dislocation (AAD), basilar invagination (BI) and Klippel-Feil anomalies, 2 patients had os odontoideum with AAD, and 1 patient each had isolated AAD and BI. Clinically, they presented with first or recurrent episodes of stroke with neck pain. Examination revealed noticeable skeletal markers and neurologic deficits involving the arterial territory. Routine stroke risk factors were absent. X-ray of CVJ was abnormal and diagnostic in all the patients. Other imaging modalities had their own contributions for identifying associated defects, demonstrating pathophysiology, and management of these patients. Acute care with anticoagulation and supportive measures helped in recovery of all of them. Posterior fusion was done in 4 patients, and 2 patients are awaiting the surgery. During follow-up all patients have improved and none had recurrences.

CONCLUSIONS

In case of a young patient with PCS (first/recurrent) in the absence of routine risk factors for stroke, careful physical examination and imaging with basic X-ray may help in the diagnosis CVJ abnormalities, which may be effectively managed by a multidisciplinary team to prevent recurrences.

Thalamic syndrome as the heralding manifestation of atlantoaxial dislocation

In India, Atlantoaxial dislocation (AAD) is the commonest skeletal craniovertebral junction (CVJ) anomaly, followed by occipitalisation of atlas and basilar invagination. The usual presentation is progressive neurological deficit (76-95% cases) involving the high cervical cord, lower brainstem and cranial nerves. The association between vertebro-basilar insufficiency and skeletal CVJ anomalies is well recognised and angiographic abnormalities of the vertebrobasilar arteries and their branches have been reported; however, initial presentation of CVJ anomaly as thalamic syndrome due to posterior circulation stroke is extremely rare. Here, we report one such rare case of thalamic syndrome as the initial presentation of CVJ anomaly with AAD.

The diagnosis of vertebrobasilar insufficiency using transcranial Doppler ultrasound

Background. Vertebrobasilar insufficiency (VBI) is a hemodynamic posterior circulation transient ischemic attack (TIA) caused by intermittent vertebral artery occlusion that is induced by a head rotation or extension. VBI may result from large vessel atherosclerotic disease, dissection, cervical compressive lesions, and subclavian steal phenomenon. Diagnostic transcranial Doppler (TCD) of VBI disease and hemodynamic posterior circulation TCD monitoring in symptomatic positions might prove a useful tool in establishing the diagnosis. Patient and Material/Method. A 50-year-old Caucasian man presented with a one-year history of episodic positional vertigo and ataxic gait that were induced by a neck extension and resolved by an upright position or a neck flexion. Computed tomography angiogram (CTA) and TCD confirmed the presence of VBI where no blood flow was detected through posterior cerebral arteries in the symptomatic position (head extension position). Conclusion. TCD is a promising noninvasive technique that might have a role as a diagnostic test in VBI.