Elsevier

Surgical Neurology

Volume 67, Issue 5, May 2007, Pages 457-464
Surgical Neurology

Aneurysm
Microsurgical treatment of unruptured intracranial aneurysms. A consecutive surgical experience consisting of 450 aneurysms treated in the endovascular era

https://doi.org/10.1016/j.surneu.2006.08.069Get rights and content

Abstract

Background

With the progressive refinement of endovascular techniques, fewer IAs are being treated with open microsurgery. There is limited information regarding the impact of this trend on the ability of younger neurosurgeons to achieve proficiency in the surgical management of IAs. We describe a consecutive series of patients with unruptured IAs treated by a neurosurgeon initiating a dedicated cerebrovascular practice in the “endovascular era.”

Methods

We retrospectively reviewed the records of all patients who had undergone surgical repair of a saccular IA by one neurosurgeon upon completion of neurosurgical training in July 1997 until April 2005. Patients with ruptured IAs were excluded from review.

Results

Of the 1450 patients with IAs treated during this period, 376 underwent microsurgical repair of 450 unruptured IAs. Microsurgical aneurysm neck clipping was possible in most cases, although distal revascularization with proximal occlusion was used in many of the more complicated aneurysms. Major complications occurred in 6 (1.60%) patients, and 1 (0.27%) patient died. At the time of 6-month follow-up, 4 (1.06%) patients were left with a new focal neurologic deficit related to surgery.

Conclusions

Despite the growing role of endovascular therapy in the management of IAs, it is possible for young neurovascular surgeons to achieve acceptable results with open microsurgical treatment of IAs. The factors that were deemed important in achieving success in this series included a collaborative approach with endovascular colleagues, careful surgical judgment, continual reanalysis of personal results, and early support from experienced mentors.

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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