AneurysmMicrosurgical treatment of unruptured intracranial aneurysms. A consecutive surgical experience consisting of 450 aneurysms treated in the endovascular era
Introduction
Over the past decade, several major factors have reduced the number of IAs treated with open microsurgical repair. The progressive refinement of endovascular techniques, including the introduction of balloon-assisted and stent-supported coiling, has substantially increased the percentage of aneurysms treated with coil embolization rather than with open surgery [1], [14], [28], [30], [31], [34], [40]. In the presence of acute SAH, results from the ISAT suggested that endovascular therapy may be associated with a lower morbidity as compared with open surgery [33]. In addition, based on the results of the ISUIA, smaller unruptured aneurysms appear to carry a more benign natural history than previously appreciated, further tempering enthusiasm for open microsurgery in this setting [18].
As fewer surgeons perform fewer open microsurgical procedures for IAs, general competence and comfort levels with this operation decline. Within academic training programs, these procedures have become less common; as a result, resident experience has become more limited. In recent years, the neurosurgical job market has increasingly emphasized the importance of endovascular skills, driving neurosurgical trainees with an interest in cerebrovascular disease toward endovascular fellowships. It is difficult to assess the subtle but definite impact that this trend has had and will have on the ability of younger neurosurgeons to become proficient in the surgical management of IAs. At the present time, however, there are many IAs that cannot be treated satisfactorily using available endovascular techniques [14], [27], [30], [43], [46]. In addition, there are many lesions that are still best managed with open microsurgery, assuming that an acceptable risk profile can be achieved. This study was performed to evaluate the outcomes achieved by a neurosurgeon initiating a dedicated cerebrovascular practice in the “endovascular era” and to assess how this practice has been affected by the decreasing number of IAs treated with open surgery.
Section snippets
Materials and methods
From July 1997 through April 2005, our institute's neurovascular service treated a total of 1450 patients with IAs, including 760 unruptured IAs. During that period, a single neurosurgeon (ESN) repaired 450 unruptured IAs in 376 patients (140 men and 236 women). The patients' ages ranged from 22 to 84 years. Of all the patients, 290 had a single aneurysm whereas 86 had multiple lesions. There were 314 (70%) small (maximal diameter, <1 cm), 99 (22%) large (maximal diameter, 1–2.5 cm), and 37
Results
Aneurysm locations and sizes are summarized in Table 1. Microsurgical neck clipping was achieved in 381 (85%) cases. Thirty-three patients underwent distal revascularization with proximal occlusion, including superficial temporal artery–to-MCA bypass in 25, SVG in 6, and radial artery graft in 2. Proximal occlusion was performed surgically at the same setting as the bypass in 25 cases and endovascularly in a delayed fashion in 5. Five patients with complex aneurysms underwent preliminary
Management philosophy
The appropriate management of unruptured IAs remains controversial. Although it appears that these lesions do not bleed often, when they do, the consequences are severe and potentially life-threatening [17], [22], [23], [44], [45], [53], [54], [57], [58]. Annual rupture rates ranging from 0.05% to 2.3% have been reported in contemporary series [18], [23], [35], [36], [52], [58]. Presumably, the true incidence lies somewhere between these estimates, with most series suggesting a rupture rate
Conclusions
We have presented a large consecutive series of patients with unruptured IAs treated by a single neurosurgeon. The acceptable morbidity and mortality rates in this complex group of patients support the idea that young neurosurgeons can become proficient in the surgical management of even very complicated IAs despite the decreasing percentage of aneurysms being treated with open surgery. Of equal importance is that it appears that this proficiency can be achieved without putting patients at
Acknowledgments
We thank Jody Lowary, Nancy Mattsen, Jane Monita, Sandy Bartz, and Char Martins for their excellent nursing assistance in the management and follow-up evaluation of the study patients. We also thank Dr Donald Erickson for providing expert surgical assistance during our early experience and Dr Leslie Nussbaum for providing assistance with the preparation of this manuscript. Finally, we thank Dr Ira Kasoff for his invaluable surgical advice.
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