Perspectives Commentary on: Microsurgical Clipping of Unruptured Middle Cerebral Artery Bifurcation Aneurysms: Incidence of and Risk Factors for Procedure-Related Complications by Chung et al. World Neurosurg 2015 http://dx.doi.org/10.1016/j.wneu.2015.01.023
Middle Cerebral Artery Bifurcation Aneurysms: When and How to Treat Asymptomatic Unruptured Aneurysms Samuel Kalb and Robert F. Spetzler
M
anagement of unruptured asymptomatic cerebral aneurysms is one of the most highly controversial and most discussed topics in vascular neurosurgery. The increasing availability and use of imaging modalities, including computed tomography with and without angiography, magnetic resonance imaging, magnetic resonance angiography, and digital subtraction angiography, has resulted in an increased number of diagnosed unruptured aneurysms. This trend has led more patients to ask if their vascular lesion should be treated and if so when should such treatment be done.
The current medical literature shows conflicting data regarding the natural history of unruptured cerebral aneurysms and the risks associated with their management. In 2003, the International Study of Unruptured Intracranial Aneurysms (ISUIA) (11) showed that aneurysms in the anterior circulation measuring 1 (5). At the present time, it is possible to decide whether the patient is a candidate for treatment on the basis of an overall assessment of clinical and radiographic risk factors, which we believe provides more than enough information for the neurovascular surgeon. However, one last piece of this divisive decision is still missing—a factor that, in many instances, provides a great enough burden to elect to treat despite scientific evidence and objective data provided to the patient. This missing element is
Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Robert F. Spetzler, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015). http://dx.doi.org/10.1016/j.wneu.2015.04.008
www.WORLDNEUROSURGERY.org
1
PERSPECTIVES
the patient’s psychosocial profile after being informed that he or she harbors an intracranial aneurysm. The daily functional life of these individuals is overshadowed by constant awareness and distress that make them feel like a “ticking time bomb.” The ensuing anxiety is often the defining factor that convinces asymptomatic patients to pursue treatment of the aneurysm. From the surgeon’s standpoint, these phenomena should be heavily weighed and understood because more recent studies have demonstrated that the quality of life in such patients could be compromised, as indicated by poorer functioning outcomes on most psychosocial measures (1, 9). The decision to treat an asymptomatic unruptured MbifA is best determined conjointly by the patient and the neurosurgeon. The next important question is, “How are we treating?” Historically, microsurgical clipping has been the management of choice for an MbifA because the peripheral location makes it easily amenable to clipping. Additional factors (e.g., giant size, wide necks, major arterial branches, frequent need for reconstruction) make these aneurysms ideal for clipping. However, it would be imprudent to ignore the evolving role of endovascular treatment for all intracranial aneurysms, which has now expanded to include MbifAs. At first, endovascular management of these aneurysms was limited by the same factors that made surgical clipping more feasible, but it was also limited by an increased risk of symptomatic thromboembolic complications to eloquent cortical areas. However, significant technologic advances in the endovascular field have made treatment feasible for vascular lesions previously considered unmanageable or for which treatment was contraindicated. Improvements in sheaths, guide catheters, distal access catheters, microcatheters, compliant balloons, and self-expanding stents, including pipeline embolization devices, have allowed many of these aneurysms with unfavorable aneurysmal necks or morphology to be treated by endovascular means (4). The current literature on endovascular treatment of MbifAs has documented occlusion rates of 83%e96%, with complication rates as high as 20%. Most of these studies included ruptured and unruptured aneurysms. In 2011, Vendrell et al. (10) reported a complete occlusion rate of 71%, a partial treatment rate of 29%, and a recurrence rate of 14.6% in a series of 52 unruptured complex aneurysms treated with stent-
REFERENCES 1. Bonares MJ, de Oliveira Manoel AL, Macdonald RL, Schweizer TA: Behavioral profile of unruptured intracranial aneurysms: a systematic review. Ann Clin Transl Neurol 1:220-232, 2014. 2. Dashti R, Hernesniemi J, Niemela M, Rinne J, Porras M, Lehecka M, Shen H, Albayrak BS, Lehto H, Koroknay-Pal P, de Oliveira RS, Perra G, Ronkainen A, Koivisto T, Jaaskelainen JE: Microneurosurgical management of middle cerebral artery bifurcation aneurysms. Surg Neurol 67: 441-456, 2007. 3. Dolati P, Pittman D, Morrish WF, Wong JH, Sutherland GR GR: The frequency of subarachnoid hemorrhage from very small cerebral aneurysms (
Middle Cerebral Artery Bifurcation Aneurysms: When and How to Treat Asymptomatic Unruptured Aneurysms Samuel Kalb and Robert F. Spetzler
M
anagement of unruptured asymptomatic cerebral aneurysms is one of the most highly controversial and most discussed topics in vascular neurosurgery. The increasing availability and use of imaging modalities, including computed tomography with and without angiography, magnetic resonance imaging, magnetic resonance angiography, and digital subtraction angiography, has resulted in an increased number of diagnosed unruptured aneurysms. This trend has led more patients to ask if their vascular lesion should be treated and if so when should such treatment be done.
The current medical literature shows conflicting data regarding the natural history of unruptured cerebral aneurysms and the risks associated with their management. In 2003, the International Study of Unruptured Intracranial Aneurysms (ISUIA) (11) showed that aneurysms in the anterior circulation measuring 1 (5). At the present time, it is possible to decide whether the patient is a candidate for treatment on the basis of an overall assessment of clinical and radiographic risk factors, which we believe provides more than enough information for the neurovascular surgeon. However, one last piece of this divisive decision is still missing—a factor that, in many instances, provides a great enough burden to elect to treat despite scientific evidence and objective data provided to the patient. This missing element is
Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Robert F. Spetzler, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015). http://dx.doi.org/10.1016/j.wneu.2015.04.008
www.WORLDNEUROSURGERY.org
1
PERSPECTIVES
the patient’s psychosocial profile after being informed that he or she harbors an intracranial aneurysm. The daily functional life of these individuals is overshadowed by constant awareness and distress that make them feel like a “ticking time bomb.” The ensuing anxiety is often the defining factor that convinces asymptomatic patients to pursue treatment of the aneurysm. From the surgeon’s standpoint, these phenomena should be heavily weighed and understood because more recent studies have demonstrated that the quality of life in such patients could be compromised, as indicated by poorer functioning outcomes on most psychosocial measures (1, 9). The decision to treat an asymptomatic unruptured MbifA is best determined conjointly by the patient and the neurosurgeon. The next important question is, “How are we treating?” Historically, microsurgical clipping has been the management of choice for an MbifA because the peripheral location makes it easily amenable to clipping. Additional factors (e.g., giant size, wide necks, major arterial branches, frequent need for reconstruction) make these aneurysms ideal for clipping. However, it would be imprudent to ignore the evolving role of endovascular treatment for all intracranial aneurysms, which has now expanded to include MbifAs. At first, endovascular management of these aneurysms was limited by the same factors that made surgical clipping more feasible, but it was also limited by an increased risk of symptomatic thromboembolic complications to eloquent cortical areas. However, significant technologic advances in the endovascular field have made treatment feasible for vascular lesions previously considered unmanageable or for which treatment was contraindicated. Improvements in sheaths, guide catheters, distal access catheters, microcatheters, compliant balloons, and self-expanding stents, including pipeline embolization devices, have allowed many of these aneurysms with unfavorable aneurysmal necks or morphology to be treated by endovascular means (4). The current literature on endovascular treatment of MbifAs has documented occlusion rates of 83%e96%, with complication rates as high as 20%. Most of these studies included ruptured and unruptured aneurysms. In 2011, Vendrell et al. (10) reported a complete occlusion rate of 71%, a partial treatment rate of 29%, and a recurrence rate of 14.6% in a series of 52 unruptured complex aneurysms treated with stent-
REFERENCES 1. Bonares MJ, de Oliveira Manoel AL, Macdonald RL, Schweizer TA: Behavioral profile of unruptured intracranial aneurysms: a systematic review. Ann Clin Transl Neurol 1:220-232, 2014. 2. Dashti R, Hernesniemi J, Niemela M, Rinne J, Porras M, Lehecka M, Shen H, Albayrak BS, Lehto H, Koroknay-Pal P, de Oliveira RS, Perra G, Ronkainen A, Koivisto T, Jaaskelainen JE: Microneurosurgical management of middle cerebral artery bifurcation aneurysms. Surg Neurol 67: 441-456, 2007. 3. Dolati P, Pittman D, Morrish WF, Wong JH, Sutherland GR GR: The frequency of subarachnoid hemorrhage from very small cerebral aneurysms (
