Decision Making in Surgery for Nonsaccular Posterior Inferior Cerebellar Artery Aneurysms With Special Reference to Intraoperative Assessment of Collateral Blood Flow and Neurophysiological Function

Abstract BACKGROUND Posterior inferior cerebellar artery (PICA) aneurysms represent a challenging pathology. PICA sacrifice is often necessary, due to the high proportion of nonsaccular aneurysms that can be found in this location. Several treatments are available, but the infrequency of these aneurysms and the increasing number of endovascular techniques have limited the development of a standardized algorithm for cases in which open surgery is indicated. OBJECTIVE We present our series of nonsaccular PICA aneurysms, in the attempt to define an algorithm for their surgical management. METHODS We retrospectively reviewed the operation database, identifying patients harboring nonsaccular PICA aneurysms who were surgically treated at our institution from 2007 to 2016. RESULTS During a 9-yr period, 17 patients harboring 18 nonsaccular PICA aneurysms were surgically treated at our institution. Fourteen (7.7%) aneurysms were located within the proximal PICA (including those located at the vertebral artery–PICA junction), and 4 were located distally. We performed PICA revascularization in 8 (57.1%) cases of proximal aneurysms (n = 4, PICA–PICA bypass; n = 4, occipital artery–PICA bypass). We based our decision whether to perform bypass on intraoperative test occlusion with indocyanine green (ICG) videoangiography and neurophysiological monitoring. In no cases, bypass was necessary for distal aneurysms. CONCLUSION For nonsaccular PICA aneurysms, in which vessel occlusion is often necessary, it is possible to adopt a selective use of revascularization techniques. Intraoperative occlusion test with ICG videoangiography and neurophysiological monitoring provides reliable indications, allowing real-time assessment of collateral circulation.

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Intracranial Bypass of Posterior Inferior Cerebellar Artery Aneurysms: Indications, Technical Aspects, and Clinical Outcomes

Operative Neurosurgery ◽

10.1093/ons/opx064 ◽

2017 ◽

Vol 13 (5) ◽

pp. 586-595 ◽

Cited By ~ 8

Author(s):

David J. Bonda ◽

Mohamad Labib ◽

Jeffrey M. Katz ◽

Rafael A. Ortiz ◽

David Chalif ◽

...

Keyword(s):

Cranial Nerve ◽

Posterior Inferior Cerebellar Artery ◽

Surgical Techniques ◽

Occipital Artery ◽

Traumatic Aneurysm ◽

Surgical Clipping ◽

Bypass Patency ◽

Cerebellar Artery ◽

Diseased Segment ◽

Pica Aneurysms

Abstract BACKGROUND: For some posterior inferior cerebellar artery (PICA) aneurysms, there is no constructive endovascular or direct surgical clipping option. Intracranial bypass is an alternative to a deconstructive technique. OBJECTIVE: To evaluate the clinical features, surgical techniques, and outcome of PICA aneurysms treated with bypass and obliteration of the diseased segment. METHODS: Retrospective review of PICA aneurysms treated via intracranial bypass was performed. Outcome measurements included postoperative stroke, cranial nerve deficits, gastrostomy/tracheostomy requirement, bypass patency, modified Rankin scale (mRS) at discharge, and mRS at 6 mo. RESULTS: Seven patients with PICA aneurysms treated with intracranial bypass were identified. Five had fusiform aneurysms (4 ruptured, 1 unruptured), 1 had a giant partially thrombosed saccular aneurysm (unruptured), and 1 had a dissecting traumatic aneurysm (ruptured). Two aneurysms were at the anteromedullary segment, 4 at the lateral medullary segment, and 1 at the tonsillomedullary segment. Three patients underwent PICA-to-PICA side to side anastomoses, 2 PICA-to-PICA reanastomosis, 1 vertebral artery-to-PICA bypass, and 1 occipital artery-PICA bypass. Six out of 7 aneurysms were obliterated surgically and 1 with additional endovascular occlusion after the bypass. All bypasses were patent intraoperatively; 2 were later demonstrated occluded without radiological signs or symptoms of stroke. No patients had new cranial nerve deficit postoperatively. With the exception of 1 death due to pulmonary emboli 3 mo postoperatively, all others remain at a mRS ≤ 2. CONCLUSION: Constructive bypass and aneurysm obliteration remains a viable alternative for treatment of PICA aneurysms not amenable to direct surgical clipping or to a vessel-preserving endovascular option.

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Surgical Management of Fusiform Aneurysms of the Peripheral Posteroinferior Cerebellar Artery

Neurosurgery ◽

10.1227/01.neu.0000084162.29616.43 ◽

2003 ◽

Vol 53 (4) ◽

pp. 831-835 ◽

Cited By ~ 37

Author(s):

Eric S. Nussbaum ◽

Alejandro Mendez ◽

Paul Camarata ◽

Leslie Sebring

Keyword(s):

Medical Records ◽

Occipital Artery ◽

Pica Pica ◽

Acute Hydrocephalus ◽

Cerebellar Artery ◽

Acute Subarachnoid Hemorrhage ◽

Pica Aneurysms ◽

Individualized Management ◽

Lost To Follow Up

Abstract OBJECTIVE To describe the management and outcomes of seven patients with fusiform aneurysms of the peripheral posteroinferior cerebellar artery (PICA). METHODS Medical records and neuroimaging studies of seven patients who underwent surgical treatment of fusiform aneurysms of the peripheral PICA were reviewed. Average follow-up time was 1.5 years, and no patient was lost to follow-up. RESULTS All patients presented with acute subarachnoid hemorrhage, and most had acute hydrocephalus. All underwent surgery, which entailed distal revascularization in six of the seven patients. Revascularization techniques included occipital artery–PICA bypass, side-to-side PICA-PICA anastomosis, and aneurysm excision with direct end-to-end PICA reanastomosis. Outcome was good in six patients and fair in one. CONCLUSION Fusiform, peripheral PICA aneurysms are rare lesions. Distal revascularization was used in most cases because of the uncertain adequacy of collateral supply. Careful, individualized management allows for a good outcome in the majority of cases.

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Reimplantation Bypass Using One Limb of a Double-Origin Posterior Inferior Cerebellar Artery for Treatment of a Ruptured Fusiform Aneurysm: Case Report

Operative Neurosurgery ◽

10.1093/ons/opaa016 ◽

2020 ◽

Vol 19 (3) ◽

pp. E314-E319 ◽

Cited By ~ 1

Author(s):

Michael J Lang ◽

Joshua S Catapano ◽

Gabriella M Paisan ◽

Stefan W Koester ◽

Tyler S Cole ◽

...

Keyword(s):

Case Report ◽

Scale Score ◽

Clinical Presentation ◽

Posterior Inferior Cerebellar Artery ◽

Pica Pica ◽

Fisher Grade ◽

Cerebellar Artery ◽

Pica Aneurysms ◽

Double Origin ◽

Variant Anatomy

Abstract BACKGROUND AND IMPORTANCE Posterior inferior cerebellar artery (PICA) aneurysms are uncommon, and aneurysms associated with anatomical PICA variants are even rarer. Although often treated endovascularly, aneurysms associated with anatomical PICA variants may not be suitable for endovascular intervention because of the risk of compromise of brainstem perforators and may be more amenable to open techniques. This case report describes the successful treatment of an aneurysm associated with a double-origin PICA (DOPICA) by distally reimplanting one of the PICA limbs. CLINICAL PRESENTATION A 78-yr-old man with a Hunt-Hess grade III, Fisher grade IV subarachnoid hemorrhage secondary to a ruptured distal right PICA aneurysm associated with a DOPICA was treated with PICA-PICA bypass and trapping of the aneurysm. This is the first reported case in the literature of successful bypass of a DOPICA-associated aneurysm. Radiographically, the bypass remained patent with successful obliteration of the aneurysm, and at discharge from the hospital, the patient had a Glasgow Coma Scale score of 15 and modified Rankin Scale score of 3. CONCLUSION This case demonstrates a novel reimplantation bypass for a ruptured aneurysm that exploits this rare variant anatomy of a DOPICA.

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Variations of Occipital Artery-Posterior Inferior Cerebellar Artery Bypass: Anatomic Consideration

Operative Neurosurgery ◽

10.1093/ons/opx152 ◽

2017 ◽

Vol 14 (5) ◽

pp. 563-571 ◽

Cited By ~ 2

Author(s):

Ken Matsushima ◽

Satoshi Matsuo ◽

Noritaka Komune ◽

Michihiro Kohno ◽

J Richard Lister

Keyword(s):

Artery Bypass ◽

Posterior Inferior Cerebellar Artery ◽

Jugular Foramen ◽

Occipital Artery ◽

Parent Artery ◽

Microsurgical Anatomy ◽

Main Trunk ◽

Cerebellar Artery ◽

Cerebellomedullary Fissure ◽

Pica Aneurysms

Abstract BACKGROUND Advances in diagnosis of posterior inferior cerebellar artery (PICA) aneurysms have revealed the high frequency of distal and/or dissecting PICA aneurysms. Surgical treatment of such aneurysms often requires revascularization of the PICA including but not limited to its caudal loop. OBJECTIVE To examine the microsurgical anatomy involved in occipital artery (OA)-PICA anastomosis at various anatomic segments of the PICA. METHODS Twenty-eight PICAs in 15 cadaveric heads were examined with the operating microscope to take morphometric measurements and explore the specific anatomy of bypass procedures. RESULTS OA bypass to the p2, p3, p4, or p5 segment was feasible with a recipient vessel of sufficient diameter. The loop wandering near the jugular foramen in the p2 segment provided sufficient length without requiring cauterization of any perforating arteries to the brainstem. Wide dissection of the cerebellomedullary fissure provided sufficient exposure for the examination of some p3 segments and all p4 segments hidden by the tonsil. OA-p5 bypass was placed at the main trunk before the bifurcation in 5 hemispheres and at the larger hemispheric trunk in others. CONCLUSION Understanding the possible variations of OA-PICA bypass may enable revascularization of the appropriate portion of the PICA when the parent artery must be occluded. A detailed anatomic understanding of each segment clarifies important technical nuances for the bypass on each segment. Dissection of the cerebellomedullary fissure helps to achieve sufficient exposure for the bypass procedures on most of the segments.

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Far Lateral Craniotomy for Posterior Inferior Cerebellar Artery–Posterior Inferior Cerebellar Artery Bypass and Trapping of Posterior Inferior Cerebellar Artery Aneurysm: 3-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opy201 ◽

2018 ◽

Vol 16 (4) ◽

pp. E119-E120 ◽

Cited By ~ 2

Author(s):

Sirin Gandhi ◽

Justin Mascitelli ◽

Douglas Hardesty ◽

Michael T Lawton

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Morphological Characteristics ◽

Occipital Artery ◽

Parent Artery ◽

Pica Pica ◽

Cerebellar Artery ◽

Patient Consent ◽

Far Lateral ◽

In Situ Bypass

Abstract Posterior inferior cerebellar artery (PICA) aneurysms account for 3% to 4% of all intracranial aneurysms with an unusually high predilection towards a nonsaccular morphology making microsurgical clipping or endovascular reconstruction of the parent artery difficult. The management of these complicated aneurysms may require revascularization procedures for flow preservation with aneurysm trapping. Recently, there is an increasing inclination towards intracranial–intracranial (IC-IC) bypasses over traditional extracranial donors. This video demonstrates a side-to-side PICA–PICA in situ bypass with trapping of an unruptured incidental right p1-PICA aneurysm. Radiological lesion progression and presence of dysplastic morphological characteristics prompted surgical management. The aneurysm was not amenable to clip reconstruction due to the dysplastic PICA segment and lack of a discernable neck. Institutional Review Board approval and patient consent were sought. With patient in three-quarter-prone position, a right far lateral craniotomy was performed. A left-to-right p3-p3 PICA bypass was completed. The aneurysm was clipped along with proximal PICA at its takeoff from vertebral artery. Indocyanine green videoangiography revealed complete occlusion of aneurysm and proximal PICA and a patent anastomosis with distal right PICA flow. Postoperatively, patient recovered with no new neurological deficits. Dolichoectatic posterior circulation aneurysms are not readily amenable to clip reconstruction. PICA–PICA in situ bypass is an elegant alternative to existing extracranial–intracranial revascularization constructs (occipital artery to PICA).1 There is lower neurological morbidity associated with IC-IC bypass vs PICA reimplantation due to the deep surgical corridor and its proximity to lower cranial nerves. Additionally, in this patient endovascular occlusion posed a higher risk of thrombotic complications and postprocedural cerebellar edema with brainstem compression.2

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Dissecting aneurysms of the posterior inferior cerebellar artery: retrospective evaluation of management and extended follow-up review in 6 patients

Journal of Neurosurgery ◽

10.3171/jns/2008/109/7/0023 ◽

2008 ◽

Vol 109 (1) ◽

pp. 23-27 ◽

Cited By ~ 35

Author(s):

Eric S. Nussbaum ◽

Michael T. Madison ◽

Mark E. Myers ◽

James Goddard ◽

Tariq Janjua

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Occipital Artery ◽

Management Protocol ◽

Cerebellar Artery ◽

Acute Subarachnoid Hemorrhage ◽

Pica Aneurysms ◽

Proximal Occlusion ◽

Individualized Management ◽

Dissecting Aneurysms

Object The authors report the management protocol and successful outcomes in 6 patients with dissecting aneurysms of the posterior inferior cerebellar artery (PICA). Methods Medical records and neuroimaging studies of 6 patients who underwent surgical treatment of dissecting PICA aneurysms were reviewed. The mean follow-up duration was 1.8 years. No patient was lost to follow-up review. Results Four patients presented with acute subarachnoid hemorrhage and 2 with PICA ischemia. All patients underwent surgery, which entailed proximal occlusion with distal revascularization in 3 cases and circumferential wrap/clip reconstruction in 3 cases. The revascularization techniques used were occipital artery–PICA bypass and PICA–PICA anastomosis. Delayed follow-up angiography was performed in all cases. In patients treated with proximal occlusion, delayed angiography showed minimal retrograde opacification of the dissected segments. The 3 patients treated with wrap/clip reconstruction showed unexpectedly significant normalization of their lesions on angiographic studies. Outcome was good in all cases. Conclusions Dissecting PICA aneurysms are rare lesions with an apparent propensity for bleeding. Individualized management including distal revascularization with PICA sacrifice or circumferential wrap/clip reconstruction to reinforce the dissected segment produced good outcomes. Patients treated with aneurysm wrapping may show dramatic angiographic improvement of the dissected segment.

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Intracranial-to-intracranial bypass for posterior inferior cerebellar artery aneurysms: options, technical challenges, and results in 35 patients

Journal of Neurosurgery ◽

10.3171/2015.5.jns15368 ◽

2016 ◽

Vol 124 (5) ◽

pp. 1275-1286 ◽

Cited By ~ 41

Author(s):

Adib A. Abla ◽

Cameron M. McDougall ◽

Jonathan D. Breshears ◽

Michael T. Lawton

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Endovascular Coiling ◽

Pica Pica ◽

Lower Cranial Nerve ◽

Complex Aneurysms ◽

Cerebellar Artery ◽

Ischemic Complications ◽

Pica Aneurysms ◽

Vascular Neurosurgery

OBJECT Intracranial-to-intracranial (IC-IC) bypasses are alternatives to traditional extracranial-to-intracranial (EC-IC) bypasses to reanastomose parent arteries, reimplant efferent branches, revascularize branches with in situ donor arteries, and reconstruct bifurcations with interposition grafts that are entirely intracranial. These bypasses represent an evolution in bypass surgery from using scalp arteries and remote donor sites toward a more local and reconstructive approach. IC-IC bypass can be utilized preferentially when revascularization is needed in the management of complex aneurysms. Experiences using IC-IC bypass, as applied to posterior inferior cerebellar artery (PICA) aneurysms in 35 patients, were reviewed. METHODS Patients with PICA aneurysms and vertebral artery (VA) aneurysms involving the PICA’s origin were identified from a prospectively maintained database of the Vascular Neurosurgery Service, and patients who underwent bypass procedures for PICA revascularization were included. RESULTS During a 17-year period in which 129 PICA aneurysms in 125 patients were treated microsurgically, 35 IC-IC bypasses were performed as part of PICA aneurysm management, including in situ p3-p3 PICA-PICA bypass in 11 patients (31%), PICA reimplantation in 9 patients (26%), reanastomosis in 14 patients (40%), and 1 V3 VA-to-PICA bypass with an interposition graft (3%). All aneurysms were completely or nearly completely obliterated, 94% of bypasses were patent, 77% of patients were improved or unchanged after treatment, and good outcomes (modified Rankin Scale ≤ 2) were observed in 76% of patients. Two patients died expectantly. Ischemic complications were limited to 2 patients in whom the bypasses occluded, and permanent lower cranial nerve morbidity was limited to 3 patients and did not compromise independent function in any of the patients. CONCLUSIONS PICA aneurysms receive the application of IC-IC bypass better than any other aneurysm, with nearly one-quarter of all PICA aneurysms treated microsurgically at our center requiring bypass without a single EC-IC bypass. The selection of PICA bypass is almost algorithmic: trapped aneurysms at the PICA origin or p1 segment are revascularized with a PICA-PICA bypass, with PICA reimplantation as an alternative; trapped p2 segment aneurysms are reanastomosed, bypassed in situ, or reimplanted; distal p3 segment aneurysms are reanastomosed or revascularized with a PICA-PICA bypass; and aneurysms of the p4 segment that are too distal for PICA-PICA bypass are reanastomosed. Interposition grafts are reserved for when these 3 primary options are unsuitable. A constructive approach that preserves the PICA with direct clipping or replaces flow with a bypass when sacrificed should remain an alternative to deconstructive PICA occlusion and endovascular coiling when complete aneurysm occlusion is unlikely.

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Far-Lateral Craniotomy for Posterior Inferior Cerebellar Artery to Occipital Artery Bypass: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opz261 ◽

2019 ◽

Vol 17 (6) ◽

pp. E234-E235

Author(s):

Benjamin K Hendricks ◽

Robert F Spetzler

Keyword(s):

Artery Bypass ◽

Video Recording ◽

Posterior Inferior Cerebellar Artery ◽

Careful Consideration ◽

Occipital Artery ◽

Institutional Review Board Approval ◽

Institutional Review ◽

Cerebellar Artery ◽

Far Lateral ◽

Pica Aneurysms

Abstract Posterior inferior cerebellar artery (PICA) aneurysms are infrequent compared with other intracranial aneurysms and are more commonly distal in origin (35% of PICA aneurysms are distal vs 6.5% of other aneurysms). This makes PICA aneurysms a surgical challenge that requires careful consideration of the patient's angiographic anatomy and perfusion needs before deciding on the appropriate intervention. This patient had a highly calcified left PICA p2 segment aneurysm, which was not favorable for endovascular intervention. An end-to-side anastomosis of the occipital artery to the p3 PICA segment was performed. This anastomosis was achieved with 11-0 suture. A permanent clip was then placed along the vertebral artery occluding both the proximal PICA and the aneurysm. Indocyanine green angiography was performed to demonstrate bypass and PICA patency. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

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Surgical clipping of a ruptured posterior inferior cerebellar artery aneurysm

Neurosurgical FOCUS ◽

10.3171/2015.v1.focus14554 ◽

2015 ◽

Vol 38 (videosuppl1) ◽

pp. Video12

Author(s):

M. Yashar S. Kalani ◽

Peter Nakaji ◽

Joseph M. Zabramski ◽

Robert F. Spetzler

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Cranial Nerves ◽

Artery Aneurysm ◽

Posterior Circulation ◽

Endovascular Techniques ◽

Surgical Clipping ◽

Cerebellar Artery ◽

Posterior Circulation Aneurysms ◽

Pica Aneurysms ◽

Lower Cranial Nerves

Posterior circulation aneurysms are commonly treated with endovascular techniques. In select cases, microsurgery remains an essential tool for treating these lesions. We present a case of a ruptured posterior inferior cerebellar artery (PICA) aneurysm approached via a craniotomy. Given the labyrinth of neurovascular bundles present in the posterior fossa, surgical exposure of PICA aneurysms can be challenging. This video demonstrates the steps of the craniotomy, subarachnoid dissection, mobilization of the vertebral artery and lower cranial nerves, and clipping of the aneurysm.The video can be found here: http://youtu.be/fQSxQj7oL0U.

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