Diagnosis, Management, and Clinical Outcomes of Tandem Thoracic and Lumbar Stenosis: A Systematic Literature Review and Case Series.

BACKGROUND: A scarcity of data has been reported on tandem thoracic lumbar stenosis, which might be related to either the rarity or underdiagnosis of the condition. We have presented a systematic review of the clinical presentation, diagnosis, and treatment patterns for patients with symptomatic tandem thoracic and lumbar stenosis. METHODS: A PubMed/MEDLINE search was performed to find reports of patients with symptomatic tandem thoracic and lumbar stenosis. RESULTS: The review identified 10 studies with a total of 48 patients with tandem thoracic and lumbar stenosis. Most patients (n = 41; 85%) had had tandem stenosis diagnosed at the initial investigation, with 71% of the reports citing ossification of the ligamentum flavum as a contributing etiology. A few patients (n = 7; 15%) had had thoracic lesions diagnosed after neurologic deterioration that had occurred after lumbar surgery for previously suspected isolated lumbar stenosis. Surgical management varied from isolated thoracic decompression, staged decompression, and simultaneous decompression. Most patients (n = 41; 87%) showed improved neurologic status after surgery. CONCLUSION: Ossification of the ligamentum flavum might play a key role in the pathogenesis of the condition. Most patients with tandem thoracic and lumbar stenosis will show improvement after surgical decompression. Although the limited evidence available has raised concerns regarding neurologic deterioration after initial lumbar decompression in patients with coexisting thoracic stenosis, the data are insufficient to definitively determine an optimal surgical strategy. Further research is needed to identify the optimal diagnostic and management criteria for patients with symptomatic tandem thoracic and lumbar stenosis.

Relationship between middle cerebral parent artery asymmetry and middle cerebral artery aneurysm rupture risk factors.

OBJECTIVE: The exact pathophysiological mechanisms underlying cerebral aneurysm formation remain unclear. Asymmetrical local vascular geometry may play a role in aneurysm formation and progression. The object of this study was to investigate the association between the geometric asymmetry of the middle cerebral artery (MCA) and the presence of MCA aneurysms and associated high-risk features. METHODS: Using a retrospective case-control study design, the authors examined MCA anatomy in all patients who had been diagnosed with an MCA aneurysm in the period from 2008 to 2017 at the University Hospitals Cleveland Medical Center. Geometric features of the MCA ipsilateral to MCA aneurysms were compared with those of the unaffected contralateral side (secondary control group). Then, MCA geometry was compared between patients with MCA aneurysms and patients who had undergone CTA for suspected vascular pathology but were ultimately found to have normal intracranial vasculature (primary control group). Parent vessel and aneurysm morphological parameters were measured, calculated, and compared between case and control groups. Associations between geometric parameters and high-risk aneurysm features were identified. RESULTS: The authors included 247 patients (158 cases and 89 controls) in the study. The aneurysm study group consisted of significantly more women and smokers than the primary control group. Patients with MCA bifurcation aneurysms had lower parent artery inflow angles (p = 0.01), lower parent artery tortuosity (p < 0.01), longer parent artery total length (p = 0.03), and a significantly greater length difference between ipsilateral and contralateral prebifurcation MCAs (p < 0.01) than those in primary controls. Type 2 MCA aneurysms (n = 89) were more likely to be associated with dome irregularity or a daughter sac and were more likely to have a higher cumulative total of high-risk features than type 1 MCA aneurysms (n = 69). CONCLUSIONS: Data in this study demonstrated that a greater degree of parent artery asymmetry for MCA aneurysms is associated with high-risk features. The authors also found that the presence of a long and less tortuous parent artery upstream of an MCA aneurysm is a common phenotype that is associated with a higher risk profile. The aneurysm parameters are easily measurable and are novel radiographic biomarkers for aneurysm risk assessment.

Potential Deep Brain Stimulation Targets for the Management of Refractory Hypertension.

Hypertension is the single greatest contributor to human disease and mortality affecting over 75 million people in the United States alone. Hypertension is defined according to the American College of Cardiology as systolic blood pressure (SBP) greater than 120 mm Hg and diastolic blood pressure (DBP) above 80 mm Hg measured on two separate occasions. While there are multiple medication classes available for blood pressure control, fewer than 50% of hypertensive patients maintain appropriate control. In fact, 0.5% of patients are refractory to medical treatment which is defined as uncontrolled blood pressure despite treatment with five classes of antihypertensive agents. With new guidelines to define hypertension that will increase the incidence of hypertension world-wide, the prevalence of refractory hypertension is expected to increase. Thus, investigation into alternative methods of blood pressure control will be crucial to reduce comorbidities such as higher risk of myocardial infarction, cardiovascular accident, aneurysm formation, heart failure, coronary artery disease, end stage renal disease, arrhythmia, left ventricular hypertrophy, intracerebral hemorrhage, hypertensive enchaphelopathy, hypertensive retinopathy, glomerulosclerosis, limb loss due to arterial occlusion, and sudden death. Recently, studies demonstrated efficacious treatment of neurological diseases with deep brain stimulation (DBS) for Tourette's, depression, intermittent explosive disorder, epilepsy, chronic pain, and headache as these diseases have defined neurophysiology with anatomical targets. Currently, clinical applications of DBS is limited to neurological conditions as such conditions have well-defined neurophysiology and anatomy. However, rapidly expanding knowledge about neuroanatomical controls of systemic conditions such as hypertension are expanding the possibilities for DBS neuromodulation. Within the central autonomic network (CAN), multiple regions play a role in homeostasis and blood pressure control that could be DBS targets. While the best defined autonomic target is the ventrolateral periaqueductal gray matter, other targets including the subcallosal neocortex, subthalamic nucleus (STN), posterior hypothalamus, rostrocaudal cingulate gyrus, orbitofrontal gyrus, and insular cortex are being further characterized as potential targets. This review aims to summarize the current knowledge regarding neurologic contribution to the pathophysiology of hypertension, delineate the complex interactions between neuroanatomic structures involved in blood pressure homeostasis, and then discuss the potential for using DBS as a treatment for refractory hypertension.