Elsevier

World Neurosurgery

Volume 83, Issue 3, March 2015, Pages 345-350
World Neurosurgery

Peer-Review Report
Indications and Results of Direct Cerebral Revascularization in the Modern Era

https://doi.org/10.1016/j.wneu.2014.10.013Get rights and content

Background

There has been a progressive decrease in the indications for cerebral revascularization during the past 30 years, particularly with the advance of endovascular techniques. Our objective was to define indications for and evaluate outcomes of patients treated with bypass surgery in the modern endovascular era.

Methods

We retrospectively reviewed the charts of all patients who underwent direct cerebral revascularization procedures between January 2006 and March 2013.

Results

In total, 121 patients underwent 131 direct microsurgical revascularization procedures. The indications for bypass surgery were moyamoya angiopathy (40 patients, 47 bypasses), complex aneurysms (54 patients, 56 bypasses), and occlusive vascular disease (27 patients, 28 bypasses). Revascularization resulted in improvement of symptoms in 77.5% of patients with moyamoya angiopathy (mean clinical follow-up 18.8 months) and 55.5% of patients with occlusive vascular disease (mean clinical follow-up 10.4 months). Among the aneurysm patients treated with revascularization, 81.5% had a favorable outcome (Glasgow Outcome Scale score 4–5) at long-term follow-up (mean clinical followup 18.5 months).

Conclusions

Although microvascular cerebral revascularization is no longer performed as commonly as in the past, it remains an essential part of the skill set required to treat select vascular pathologies. Complex aneurysms are the single largest indication for direct bypass procedures. Moyamoya disease is by far the largest indication if indirect bypass procedures are included in the analysis. In experienced hands, the morbidity and mortality of patients undergoing cerebral revascularization procedures are low and long-term outcomes generally excellent.

Introduction

Microvascular bypass surgery was introduced by Yaşargil in 1970 (30) and rapidly became a mainstay in the treatment of patients with intracranial ischemia. However, improvements in medical management and the publication of results from the extracranial-intracranial (EC-IC) bypass trial and subsequent Carotid Occlusion Surgery Study trial have dampened enthusiasm for the use of bypasses for intracranial ischemias 2, 23. At the same time, advances in chemotherapy combined with better and more precise radiation techniques have reduced the use of cerebral revascularization for treating complex skull base tumors (15). The introduction and refinement of endovascular techniques that began in the 1990s also led to a decrease in the use of bypass techniques for giant and complex aneurysms, where revascularization and trapping was once the definitive treatment 14, 16, 17, 18.

Cerebral revascularization remains the primary treatment in certain neurovascular diseases, such as moyamoya angiopathy, but these cases are uncommon, and patients are rarely treated outside of major tertiary care centers 4, 7, 13, 27. The changes in the aforementioned practice paradigms outlined and the decrease in the use of bypass techniques beget 2 important and related questions: What are the current indications for cerebral revascularization? With a decreasing number of bypass procedures being performed, do the results of microvascular bypass surgery remain comparable to historical controls?

To address these questions, we retrospectively reviewed all direct cerebral revascularization procedures performed at our center in the modern endovascular era (2006−2013) to evaluate indications for their use and the outcome of patients, with special emphasis on the rates of morbidity and mortality associated with the use of bypass.

Section snippets

Patient Population

Between January 2006 and March 2013, 121 consecutive patients underwent direct microsurgical cerebral revascularization alone or in combination with other procedures. Patients with penetrating intracranial trauma were excluded from this analysis. Medical records, neurological examinations, and radiographic studies were reviewed retrospectively. Pre- and postoperative neurological function was evaluated via Glasgow Outcome Scale (GOS) scores. Patients undergoing cerebral revascularization in

Results

Altogether, 121 patients (75 female, 46 male) with a mean age of 46.6 years (range, 1−87 years) underwent 131 direct cerebral revascularization procedures. The indications for revascularization and overall patient characteristics are summarized in Table 1. In total we performed 47 (35.9%) revascularization procedures for 40 patients with moyamoya disease, 56 (42.7%) procedures for 54 patients with complex aneurysms, and 28 (21.4%) procedures for 27 patients with occlusive vascular disease

Discussion

Advances in the medical management of patients with cerebral ischemia, targeted therapies for malignancies, and expanding endovascular techniques have resulted in a significant decrease in the indications for microvascular cerebral revascularization. As an example, we previously reported the results of our experience in 18 patients who underwent carotid artery occlusion and bypass for malignancies involving the skull base (15). In contrast to this previous report, we did not perform a single

Conclusion

The introduction of more effective medical therapies, targeted chemotherapeutics and novel radiation, and endovascular techniques has changed the traditional paradigm of and indications for cerebral revascularization. Whereas bypass surgery has been used since its inception as a mainstay for treating intracranial occlusive disease and was widely used as an adjunct in the treatment of skull base tumors and aneurysms, the numbers of cases in which these techniques are still used are diminishing.

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