Fusion surgery for recurrent cerebellar infarctions due to bilateral atlantoaxial rotational vertebral artery occlusion

Embolic stroke induced by rotational persistent 1st intersegmental artery compression

A 45-year-old man suffered multiple cerebral infarctions in the vertebrobasilar artery territory, followed by second stroke against conservative treatment. Radiological examinations revealed intra-arterial defect in left persistent 1st intersegmental artery (PFIA) at C1 level, suggesting mural thrombus, and mechanical compression of left PFIA at the level with head rotation to the right clearly revealed by reconstructed 3-dimensional radiological images, but no findings of atlantoaxial instability. One month after the second stroke, posterior fixation was performed. Postoperative course was uneventful without subsequent stroke for 24 months. This unique case demonstrated that PFIA might associate with cerebral stroke as a clinical condition of bow hunter's stroke even in middle age. Reconstructed 3-dimensional radiological images might be useful for clear demonstration of the pathophysiology in this complex clinical entity.

Ischemic Stroke Secondary to Dynamic Vertebral Artery Stenosis: Case Report and Review of the Literature

Ischemic stroke secondary to dynamic vertebral artery stenosis or occlusion, also known as “bow hunter's syndrome,” is a rare stroke mechanism. We report a case of a 24-year-old man with multiple hereditary exostosis (MHE) diagnosed at childhood. His first presentation to a neurologist was due to neck pain and clinical syndrome suggestive of ischemia in the vertebrobasilar territory. A therapeutic occlusion was done successfully without complication. The patient was discharged two days later on aspirin alone. In follow up one year later he continued to be symptom free. Moreover, this stroke mechanism has been reported extensively in the literature in isolation or secondary to many underlying diseases. In total, there are 168 cases reported in the published English literature, in either case reports or small series. In this review, we found that by far, vertebral artery occlusion at the atlanto-axial (C1-2) level dominated most reported cases. The most frequent presentation that led to further investigation was syncope or pre-syncope provoked by head rotation to one side. To our knowledge, there is no previous report of any stroke syndrome related to MHE before our case. In this paper, we report the first case secondary to MHE and review the literature up to date since the first reported case in 1952.

Rotational vertebral artery occlusion ("bow hunter syndrome")

PURPOSE

To review the literature, analyze and discuss diagnostic and treatment options for the Bowhunter Syndrome. A clinical case of idiopathic rotatory C1-C2 subluxation causing dynamic vertebral artery occlusion is presented.

METHODS

Literature review between 1960 and 2019, discussion of diagnostic methods and treatment options. Description of diagnostic and treatment methods in the aforementioned case.

RESULTS

We present a patient with dynamic left vertebral artery occlusion associated with idiopathic rotatory C1-C2 subluxation. A dynamic Angio-CT showed rotatory C1-C2 subluxation with significant flow reduction at the left vertebral artery at the exit of the C2 transverse foramen until the V3 segment when the head rotated towards the right. Due to clinical and radiological worsening in the following months, posterior C1-C2 arthrodesis was performed, with the disappearance of the symptoms. There are 193 cases reported with dynamic vertebral artery occlusion, but in only two, the etiology was primary rotational atlantoaxial instability. The most prevalent etiology was degenerative.

CONCLUSION

Rotatory vertebral artery occlusion is a rare condition presented mostly in adults, aged 50-70 years. Vertebrobasilar insufficiency is triggered by the rotation of the head to the contralateral side of the dominant vertebral artery. Dynamic subtraction angiography is considered the diagnostic gold-standard method, but dynamic Angio-CT scan, Angio-MRI, or Doppler ultrasonography are less invasive options. The treatment options are conservative or surgical. Endovascular surgery is another option in specific cases.

Posterior atlantoaxial fusion using a C2 transverse foramen-penetrating screw: A technical note

Background:

Although recent development of screw instrumentation techniques for rigid fixation of the atlantoaxial joint has increased surgical options, patients in whom screws of any type cannot be safely placed are sometimes encountered. We present a unique surgical technique for C1-2 transarticular screw placement utilizing a novel trajectory.

Methods:

A 35-year-old male with a history of Down's syndrome and cognitive dysfunction with hyperkinesis spontaneously developed rapid onset of tetraparesis and gait disturbance. Radiographs of the cervical spine revealed atlantoaxial subluxation (AAS) that could not be reduced. Computed tomography (CT) of the head showed multiple subacute cerebral infarctions in the territory of the right vertebral artery (VA). Three-dimensional CT angiography of the craniovertebral junction additionally confirmed right VA occlusion at the C2/3 level, a left C2 origin of the posterior inferior cerebellar artery, and hypoplasia of the bilateral C2 pedicles/C2 lamina. Because traditional screw-placement was not feasible, we performed a unique atlantoaxial fusion utilizing a C2 transverse foramen-penetrating screw with iliac bone grafting performed under neuronavigation.

Results:

The postoperative course was uneventful, and the patient regained the ability to ambulate, returning to his previous level of function. The CT of the cervical spine 12 months postoperatively showed rigid bony C1-C2 fusion, without recurrence of stroke.

Conclusion:

We introduced a novel C1-C2 transarticular screw-placement technique in which the trajectory went through the ipsilateral VA foramen due to already extent VA occlusion.

Complications, Readmissions, and Reoperations in Posterior Cervical Fusion

STUDY DESIGN

Retrospective cohort study of the American College of Surgeons National Surgical Quality Improvement Program database from 2011 to 2012.

OBJECTIVE

Minimizing the morbidity of posterior cervical fusion can be improved with identification of patient risk factors.

SUMMARY OF BACKGROUND DATA

Posterior cervical fusion is an effective technique for treating a variety of pathology. Stability and neurological improvement have been well documented. The increasing frequency of these procedures necessitates further investigation into the factors that may negatively impact perioperative care.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program was queried for all patients undergoing posterior cervical fusion in 2011 and 2012. Preoperative and intraoperative variables were investigated for correlation to complications, readmissions, prolonged intubation, reintubation, and reoperation. A frailty-based score was used to assess preoperative risk. Regression models for prediction were performed.

RESULTS

The study identified 5627 patients of posterior cervical fusion in 2011 and 2012. Of these, 2029 patients (36.1%) had any of our identified complications. Transfusion was the most common in 1482 (26.3%) patients. Excluding transfusion, the complication rate was 9.8%. Prolonged intubation greater than 48 hours occurred in 83 (1.5%) patients. Reintubation occurred in 72 (1.3%) patients. Readmission occurred in 398 (7.8%) patients. Reoperation was necessary in 273 (4.9%) patients with postoperative infection being the most common reason. The frailty-based score was shown to be predictive of any of the above events (P < 0.0001). The majority of patients (54.9%) in the group that had complications was found to have a frailty score of 1 or higher.

CONCLUSION

The predictors for any event included female sex, increased surgical time, combined anterior-posterior procedures, preoperative inpatient status, diabetes, smoking, American Society of Anesthesiologists class 3 or higher, and increasing age. The frailty-based score is a viable option to predict morbidity in posterior cervical fusion.Level of Evidence: 3.

Juvenile Cerebral Infarction Caused by Bow Hunter's Syndrome during Sport: Two Case Reports

We report two cases of juvenile cerebral infarction caused by bow hunter's syndrome (BHS) during sport. Case 1 was a 17-year-old male who developed a partial visual field defect after playing basketball. BHS was diagnosed because cervical ultrasonography demonstrated occlusion of the vertebral artery when the neck was rotated. After C1-2 posterior fixation was performed, his symptoms resolved. Case 2 was an 18-year-old male with recurrent visual disturbance after playing handball. Cerebral infarction occurred repeatedly despite antiplatelet therapy. After 3 years, vertebral artery dissection was diagnosed and stenting was performed, but his symptoms did not resolve. BHS was diagnosed when he was examined at our department. C1-2 posterior fixation was performed and his symptoms resolved. In these two cases, BHS was caused by sporting activity. For accurate diagnosis and treatment of BHS, neuroimaging with cervical rotation is mandatory.

Posterior atlantoaxial fusion as treatment option for extracranial vertebral artery dissecting aneurysm: a case report and literature review

Symptomatic extracranial vertebral artery (VA) dissection may need surgery. We describe such a case successfully treated with atlantoaxial fusion based on its rare dynamic angiographic findings. A 27-year-old woman suffered from repeated brainstem and cerebellar infarctions from a left extracranial VA dissecting aneurysm. Dynamic angiography showed the dissecting aneurysm of the V3 segment in the neutral head position, and deflation of the aneurysm during rightward head rotation. She underwent posterior atlantoaxial fusion, and the lesion was repaired with no subsequent ischemia. Posterior atlantoaxial fusion can be an option for some extracranial VA dissections with preserving its anterograde blood flow.

Advances in the Pathogenesis, Diagnosis and Treatment of Bow Hunter's Syndrome: A Comprehensive Review of the Literature

Bow hunter's syndrome (BHS), also known as rotational vertebral artery (VA) occlusion syndrome, is a rare yet treatable type of symptomatic vertebrobasilar insufficiency resulting from mechanical occlusion or stenosis of the VA during head and neck rotation or extension. The symptoms of BHS range from transient vertigo to posterior circulation stroke. The underlying pathology is dynamic stenosis or compression of the VA by abnormal bony structures with neck rotation or extension in many cases, such as osteophyte, disc herniation, cervical spondylosis, tendinous bands or tumors. Imaging approaches, such as Doppler sonography, computed tomography and angiography, as well as magnetic resonance imaging and angiography, are widely used in the diagnosis and evaluation of this syndrome. Digital subtraction angiography with head rotation remains the gold standard diagnostic method. Conservative management, surgery and endovascular procedures are the three major treatment methods for BHS, whereas some symptomatic patients may need operative treatment including surgery and endovascular procedures when conservative management is not adequate.

Rheumatoid arthritis-induced lateral atlantoaxial subluxation with multiple vertebrobasilar infarctions

STUDY DESIGN

Case report.

OBJECTIVE

To highlight the probability that lateral atlantoaxial subluxation (AAS) exists in patients with rheumatoid arthritis (RA) and induces vertebrobasilar infarctions that are more foregrounded than compressive myelopathy.

SUMMARY OF BACKGROUND DATA

Although lateral subluxation is a well-known subtype of AAS, a case of cerebral ischemia associated with lateral AAS has not been reported before.

METHODS

A 52-year-old male with a 6-year history of RA had a sudden onset of visual field defect and mild right cerebellar ataxia. Head magnetic resonance imaging revealed acute multiple infarctions in the vertebrobasilar area, and magnetic resonance angiography revealed stenosis of the left vertebral artery (VA). Lateral radiograph of the cervical spine in the neutral position revealed atlanto-occipital assimilation and anterior AAS. T2-weighted sagittal images on cervical magnetic resonance imaging revealed high signal intensity in the spinal cord at C1-C2. Cerebral angiography revealed right VA occlusion and severe stenosis of the left V3 segment of VA. Three-dimensional computed tomography angiography of the craniovertebral junction revealed lateral AAS, which was due to severe erosive changes of the facet joints, and the left V3 portion was stenosed by a bony component. During conservative therapy, the patient experienced left occulomotor nerve palsy due to a second stroke.

RESULTS

Two months later, the patient underwent occipitocervical posterior fusion with an iliac bone graft. His postoperative course was uneventful, and the left VA stenosis disappeared. At the 45-month follow-up, he had no further infarctions. Bony fusion was radiologically confirmed, and 3-dimensional computed tomography angiography revealed good patency of the affected left VA.

CONCLUSION

In patients with RA, the potential risk of AAS should be recognized. Lateral AAS in particular may induce cerebral ischemia by positional VA occlusion in advanced stages of the disease.

LEVEL OF EVIDENCE

N/A.