Trends in Literature on Cerebral Bypass Surgery: A Systematic Review

Abstract

<b><i>Introduction:</i></b> Ever since the beginning of cerebral bypass surgery, the role of the bypass has been debated and indications have changed over the last 5 decades. This systematic literature research analysed all clinical studies on cerebral bypass that have been published from January 1959 to January 2020 for their year of publication, country of origin, citation index, role of and indication for bypass, bypass technique, revascularized territory, flow capacity, and title (for word cloud analysis per decade). <b><i>Methods:</i></b> A systematic literature research was conducted using PubMed, Web of Science, EMBASE, and SCOPUS databases. All studies that have been published until January 1, 2020, were included. <b><i>Results:</i></b> Of 6,013 identified studies, 2,585 were included in the analysis. Of these, <i>n</i> = 1,734 (67%) studies addressed flow-augmentation bypass and <i>n</i> = 701 (27%) addressed flow-preservation bypass. The most common indication reported for flow augmentation is moyamoya (<i>n</i> = 877, 51%), followed by atherosclerotic steno-occlusive disease (<i>n</i> = 753, 43%). For flow preservation, the most common indication is studies reporting on cerebral aneurysm surgery (<i>n</i> = 659, 94%). The increasing popularity of reporting on these bypass operations almost came to an end with the FDA approval of flow diverters for aneurysm treatment in 2011. Japan is the country with the most bypass studies (cumulatively published 933 articles), followed by the USA (630 articles) and China (232 articles). <b><i>Discussion/Conclusion:</i></b> Clinical studies on cerebral bypass surgery have become increasingly popular in the past decades. Since the introduction of moyamoya as a distinct pathologic entity, Asian countries in particular have a very active community regarding this disease, with an increasing number of articles published every year. Studies on bypass for chronic steno-occlusive disease peaked in the 1980s but have remained the main focus of bypass research, particularly in many European departments. The number of reports published on these bypass operations significantly decreased after the FDA approval of flow diverters for aneurysm treatment in 2011.

Application of individual brain connectome in chronic ischemia: mapping symptoms before and after reperfusion

“…Bypass surgery is effective for the treatment of chronic steno‐occlusive vasculopathy (CSOV) by reducing the risk of future stroke, reducing frequency of transient ischemic attacks, and improving long‐term cognitive function and activities of daily living. 1 , 2 , 3 The surgery is recommended to be performed as soon as it can be reasonably scheduled after the acute phase. 4 , 5 Nevertheless, not all patients benefit from this gold‐standard surgery due to postoperative ischemia, hyperperfusion syndrome (HPS) and other unknown reasons.…”

Association of Bypass Surgery and Mortality in Moyamoya Disease

“…Extracranial to intracranial bypass surgery for flow augmentation in MMD has been performed mostly in Asian countries due to its pathological entity, and research is increasing every year. 7 To our knowledge, only one Japanese trial has revealed that bypass surgery in adult patients with hemorrhagic moyamoya reduces recurrent bleeding or related death or severe disability with marginal significance. 8 Regarding patients with ischemic or asymptomatic MMD, there have been no randomized trials.…”