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

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.

Download Full-text

Cerebral revascularization performed using posterior inferior cerebellar artery—posterior inferior cerebellar artery bypass

Journal of Neurosurgery ◽

10.3171/jns.2002.97.1.0219 ◽

2002 ◽

Vol 97 (1) ◽

pp. 219-223 ◽

Cited By ~ 54

Author(s):

G. Michael Lemole ◽

Jeffrey Henn ◽

Sam Javedan ◽

Vivek Deshmukh ◽

Robert F. Spetzler

Keyword(s):

Artery Bypass ◽

Posterior Inferior Cerebellar Artery ◽

Surgical Techniques ◽

Cerebral Revascularization ◽

Pica Pica ◽

Content Type ◽

Cerebellar Artery ◽

In Situ Bypass ◽

Fine Print

✓ Cerebral revascularization is often required for the surgical treatment of complex intracranial aneurysms. In certain anatomical locations, vascular anatomy and redundancy make in situ bypass possible. The authors present four patients who underwent revascularization performed using the rarely reported posterior inferior cerebellar artery (PICA)—PICA in situ bypass after their aneurysms had been trapped. At Barrow Neurological Institute, between 1991 and the present, four male patients underwent PICA—PICA bypasses to treat aneurysms involving the vertebral artery, the PICA, or both. The mean age of these patients was 34 years (range 5–49 years). Follow-up studies revealed patent bypasses and no evidence of infarction. Patient outcomes were excellent or good. Multiple surgical techniques have been described for revascularization of at-risk cerebral territories. Often, the blood supply must be derived from extracranial sources through a mobilized pedicle or interposited graft. Certain anatomical locations such as the vertebrobasilar junction, the anterior circle of Willis, and the middle cerebral artery bifurcation are amenable to in situ bypass because there is vessel redundancy or proximity to the contralateral analogous vessel. The advantages of an in situ bypass include one suture line, a short bypass distance, and a close match with the caliber of the recipient graft. Although technically challenging, this technique can be successful and should be considered for appropriate candidates.

Download Full-text

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

Operative Neurosurgery ◽

10.1093/ons/opx141 ◽

2017 ◽

Vol 14 (4) ◽

pp. 422-431 ◽

Cited By ~ 1

Author(s):

Alessandro Narducci ◽

Ran Xu ◽

Peter Vajkoczy

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Neurophysiological Monitoring ◽

Occipital Artery ◽

Pica Pica ◽

Endovascular Techniques ◽

Vessel Occlusion ◽

Cerebellar Artery ◽

Pica Aneurysms ◽

Intraoperative Test ◽

Time Assessment

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.

Download Full-text

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.

Download Full-text

Endovascular Coiling for Saccular Vertebral Artery-Posterior Inferior Cerebellar Artery (VA-PICA) Aneurysms: Morphological Considerations Based on a Single Center Experience of Endovascular Coiling as the First Line Therapy

Surgery for Cerebral Stroke ◽

10.2335/scs.42.95 ◽

2014 ◽

Vol 42 (2) ◽

pp. 95-102

Author(s):

Tomosato YAMAZAKI ◽

Noriyuki KATO ◽

Hiromichi KASUYA ◽

Hisayuki HOSOO ◽

Makoto SONOBE

Keyword(s):

Vertebral Artery ◽

Posterior Inferior Cerebellar Artery ◽

Endovascular Coiling ◽

Single Center ◽

First Line ◽

Single Center Experience ◽

First Line Therapy ◽

Line Therapy ◽

Cerebellar Artery ◽

Pica Aneurysms

Download Full-text

Surgical Management and Outcomes of Aneurysms of Posterior Inferior Cerebellar Artery: Location-Based Approaches with Review of Literature

Journal of Neurosciences in Rural Practice ◽

10.1055/s-0039-3399486 ◽

2020 ◽

Vol 11 (01) ◽

pp. 034-043

Author(s):

Harsh Deora ◽

Nitish Nayak ◽

Priyadarshi Dixit ◽

V. Vikas ◽

K. V. L. Narasinga Rao ◽

...

Keyword(s):

Surgical Management ◽

Posterior Inferior Cerebellar Artery ◽

Lower Cranial Nerve ◽

Common Location ◽

Neurosurgical Society ◽

Cranial Nerve Palsies ◽

Cerebellar Artery ◽

Far Lateral Approach ◽

Pica Aneurysms

Abstract Background Posterior inferior cerebellar artery (PICA) is a tortuous, variable, and uncommon site for aneurysms. Surgical management of PICA aneurysms involves careful selection of approach based on the location of the aneurysm and meticulous dissection of the neurovascular structures and perforators. Materials and Methods We did a retrospective review of all the PICA aneurysms operated at our institute in the past 10 years along with the site, presentation, and approach used for the same. Preoperative World Federation of Neurosurgical Society scores and follow-up modified Rankin scores (mRS) were also evaluated. During the same period, data for intervention cases of PICA aneurysm were also collected with follow-ups for a comparative analysis. Results A total of 20 patients with 21 PICA aneurysms were reviewed. All the reviewed cases presented with subarachnoid hemorrhage, and the most common location was the lateral medullary segment and vertebral artery (VA)–PICA junction. Midline approaches were used for distal PICA cases, with far-lateral approach reserved for anterior medullary/VA–PICA junction. No lower cranial nerve palsies were recorded at follow-up. Four cases needed cerebrospinal fluid diversion and two developed cerebellar infarcts. All cases were mRS 0 to 2 at follow-up. Conclusion Our series compares well with some of the larger surgical series of PICA aneurysms. This may be due to early referral patterns and early surgery (<24 hours) policy at our institution. Anatomical knowledge of PICA anatomy and sound perioperative management are keys to good outcomes in these cases.

Download Full-text

Operative Nuances of Side-to-Side In Situ Posterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Bypass Procedure

Operative Neurosurgery ◽

10.1227/neu.0b013e3181f7420e ◽

2010 ◽

Vol 67 (suppl_2) ◽

pp. ons471-ons477 ◽

Cited By ~ 1

Author(s):

Miikka Korja ◽

Chandranath Sen ◽

David Langer

Keyword(s):

Indocyanine Green ◽

Indocyanine Green Angiography ◽

Posterior Inferior Cerebellar Artery ◽

Posterior Circulation ◽

Treatment Modalities ◽

Bypass Operation ◽

Pica Pica ◽

Bypass Procedure ◽

Cerebellar Artery

ABSTRACT BACKGROUND: An intracranial posterior circulation revascularization procedure in the form of a side-to-side in situ posterior inferior cerebellar artery (PICA)-PICA bypass operation was introduced in 1991. This elegant and apparently low-risk operation is performed infrequently. Thus, the operative nuances used in this procedure have not been well reported, limiting the scope of treatment modalities of vertebral artery-PICA aneurysms and vertebral dissections. OBJECTIVE: To repair an incidental right-sided PICA aneurysm noted in a 51-year-old woman in magnetic resonance imaging and subsequent angiography. METHODS: The patient underwent side-to-side in situ PICA-PICA bypass surgery. RESULTS: Immediate indocyanine green angiography suggested that the PICA distal to the aneurysms was filling in a retrograde fashion through the bypass. On the following day, the patient was taken for coil embolization of the aneurysm. However, angiography images revealed that the aneurysm was spontaneously thrombosed, the proximal PICA was patent, and the PICA distal to the aneurysms was filling in a retrograde fashion, as suspected in intraoperative indocyanine green angiography. No further treatments were done. The patient recovered fully. CONCLUSION: We describe in detail the preoperative evaluation, decision process, and operative techniques for a side-to-side in situ PICA-PICA bypass operation, which is a relatively safe and elegant posterior circulation bypass procedure.

Download Full-text

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

Download Full-text

Onyx embolization in distal dissecting posterior inferior cerebellar artery aneurysms

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2014-011622 ◽

2015 ◽

Vol 8 (5) ◽

pp. 501-506 ◽

Cited By ~ 7

Author(s):

Ajit S Puri ◽

Francesco Massari ◽

Samuel Y Hou ◽

Juan Diego Lozano ◽

Mary Howk ◽

...

Keyword(s):

Diagnostic Imaging ◽

Posterior Inferior Cerebellar Artery ◽

Clinical Results ◽

Endovascular Coiling ◽

Parent Artery ◽

Small Series ◽

Cerebellar Artery ◽

Mild Disability ◽

Pica Aneurysms

BackgroundDissecting aneurysms located along the distal segments of the posterior inferior cerebellar artery (PICA) are extremely rare, accounting for only 0.5–0.7% of all intracranial aneurysms. Treatment of these aneurysms is challenging, both surgically and endovascularly. We present our preliminary experience and clinical data utilizing Onyx as an embolization agent in the treatment of these lesions with proximal parent artery preservation.Methods7 consecutive ruptured peripheral PICA aneurysms, in 7 patients, were treated with superselective Onyx embolization at our institutions. According to the anatomical classification of Lister et al, these aneurysms were located in the lateral medullary segment (n=1), tonsillomedullary segment (n=1), and the telovelotonsillary segment (n=5) of the PICA. Technical feasibility, procedure related complications, angiographic results, follow-up diagnostic imaging, and clinical outcome were evaluated.ResultsIn all cases, endovascular treatment was successful, with complete occlusion of the aneurysm with proximal parent artery preservation at the final postprocedural angiogram. Procedure related complications were not observed. One patient with a poor clinical condition at admission died during the initial hospital stay due to extensive subarachnoid and intraventricular hemorrhage. No rebleeding or recanalization was noted during follow-up. Two patients had a residual moderate to severe disability at follow-up. Favorable outcomes, with no or mild disability, were observed in four of the surviving patients.ConclusionsAngiographic, diagnostic imaging, and clinical results of our small series indicate that Onyx embolization of dissecting distal PICA aneurysms with parent artery preservation is an effective option with acceptable morbidity and mortality rate, in those cases in which surgical clipping or endovascular coiling of the aneurysmal sac is not suitable.

Download Full-text