BACKGROUND Carotid endarterectomy (CEA) and carotid artery stenting (CAS) represent options to treat many patients with carotid stenosis. Although randomized trial data are plentiful, estimated rates of morbidity and mortality for both CEA and CAS have varied substantially. OBJECTIVE To evaluate rates of adverse outcomes after CAS and CEA in a large national database. METHODS We analyzed 84 191 adult patients undergoing elective, nonemergent CAS (n = 81 361) or CEA (n = 2830), from 2011 to 2018, in the American College of Surgeons’ National Surgical Quality Improvement Program database. Odds of adverse outcomes (30-d rates of stroke, myocardial infarction (MI), cardiac arrest, prolonged length of stay (LOS), readmission, reoperation, and mortality) were evaluated in propensity-matched (n = 2821) cohorts through logistic regression. RESULTS In the propensity-matched cohorts, CAS had increased odds of periprocedural stroke (odds ratio [OR] 1.97, 95% CI 1.32-2.95) and decreased odds of cardiac arrest (OR 0.33, 95% CI 0.13-0.84) and 30-d reoperation (OR 0.59, 95% CI 0.44-0.80) compared to CEA. Relative odds of MI, prolonged LOS, discharge to destination other than home, 30-d readmission, or 30-d mortality were statistically similar. In the unmatched patient population, rates of adverse outcomes with CEA were constant over time; however, for CAS, rates of stroke increased over time. In both the matched and unmatched patient cohorts, patients 70 yr and older had lower rates of post-procedural stroke with CEA, but not with CAS, compared to younger patients. CONCLUSION In a propensity-matched analysis of a large, prospectively collected, national, surgical database, CAS was associated with increased odds of periprocedural stroke, which increased over time. Rates of MI and death were not significantly different between the 2 procedures.

In Chiari Malformation Type I (CM1), low-lying tonsils obstruct the cisterna magna at the foramen magnum, thereby compromising the essential juncture between the cranial and spinal compartments. The anatomical obstruction of the cisterna magna inhibits bi-directional CSF flow as well as CSF pulse pressure equilibration between the intracranial compartment and the intraspinal compartment in response to instances of increased intracranial pressure. Less understood, however, are the roles of the spinal cord suspension structures at the craniocervical junction which lend viscoelastic support to the spinal cord and tonsils, as well as maintain the anatomical integrity of the cisterna magna and the dura. These include extradural ligaments including the myodural bridges (MDBs), as well as intradural dentate ligaments and the arachnoid framework. We propose that when these elements are disrupted by the cisterna magna obstruction, tonsillar pathology, and altered CSF dynamics, there may arise a secondary pathophysiology of compromised and dysfunctional cranio-spinal suspension in CM1. We present intraoperative images and videos captured during surgical exposure of the craniocervical junction in CM1 to illustrate this proposal.

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