Background/Importance Delayed cerebral ischemia (DCI) is the second-leading cause of death and disability in patients with aneurysmal subarachnoid hemorrhage (aSAH), and is associated with cerebral arterial vasospasm (CAV). Current treatments for CAV are expensive, invasive, and have limited efficacy. Cervical sympathetic block (CSB) is an underappreciated, but potentially highly effective therapy for CAV.
Objective To provide a comprehensive review of the preclinical and human literature pertinent to CSB in the context of CAV.
Evidence review This study followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines. We conducted a literature search using Embase, PubMed, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Scopus and Web of Science until February 2022, to identify abstracts, conference proceedings, and full-text papers pertinent to cervical sympathectomy and CAV in animal/adult patients.
Findings We included six human and six experimental studies. Human studies were mostly prospective observational, except one retrospective and one randomized clinical trial, and used various imaging modalities to measure changes in arterial diameter after the block. Studies that used digital subtraction angiography showed an improvement in cerebral perfusion without change in vessel diameter. Transcranial Doppler studies found an approximately 15% statistically significant decrease in velocities consistent with arterial vasodilatation. Overall, the results suggest an increase in cerebral arterial diameter and neurological improvement in patients receiving a CSB. Animal studies demonstrate that sympathetic system ablation vasodilates cerebral vasculature and decreases the incidence of symptomatic vasospasm.
Conclusions This scoping review suggests that CSB may be a viable option for treatment and prevention of CAV/DCI in patients with aSAH, although the included studies were heterogeneous, mostly observational, and with a small sample size. Further research is needed to standardize the technique and prove its effectiveness to treat patients suffering of CAV/DCI after aSAH.
- nerve block
- neurologic manifestations
- outcome assessment, health care
- critical care
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Contributors Study conception: AMB; Protocol writing: AMB; Systematic literature search and update: librarian non-coauthor. Selection of citations and articles for eligibility: AMB and BDH; Data extraction: AMB; Data analysis/interpretation: AMB, BDH and JJH; Drafting of paper: AMB; Revising of paper: AMB, BDH, JJH, GWA, MT, GKS; Approval of final version: all authors.
Funding This work was in part supported by a generous gift to Dr. Heit from the CNYL Foundation.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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