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Michael T Lawton - One of the best experts on this subject based on the ideXlab platform.
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revascularization of the posterior inferior cerebellar artery using the occipital artery a cadaveric study comparing the p3 and p1 recipient sites
Operative Neurosurgery, 2020Co-Authors: Peyton L Nisson, Ali Tayebi Meybodi, Arnau Benet, Xinmin Ding, Ryan Palsma, Michael T LawtonAbstract:BACKGROUND Revascularization of the posterior inferior cerebellar artery (Pica) is tyPically performed with the occipital artery (OA) as an extracranial donor. The p3 segment is the most accessible recipient site for OA-Pica bypass at its caudal loop inferior to the cerebellar tonsil, but this site may be absent or hidden due to a high-riding location. OBJECTIVE To test our hypothesis that freeing p1 Pica from its origin, transposing the recipient into a shallower position, and performing OA-p1 Pica bypass with an end-to-end anastomosis would facilitate this bypass. METHODS The OA was harvested, and a far lateral craniotomy was performed in 16 cadaveric specimens. Pica caliber and number of perforators were measured at p1 and p3 segments. OA-p3 Pica end-to-side and OA-p1 Pica end-to-end bypasses were compared. RESULTS OA-p1 Pica bypass with end-to-end anastomosis was performed in 16 specimens; whereas, OA-p3 Pica bypass with end-to-side anastomosis was performed in 11. Mean distance from OA at the occipital groove to the anastomosis site was shorter for p1 than p3 segments (30.2 vs 48.5 mm; P < .001). Median number of perforators on p1 was 1, and on p3, it was 4 (P < .001). CONCLUSION Although most OA-Pica bypasses can be performed using the p3 segment as the recipient site for an end-to-side anastomosis, a more feasible alternative to conventional OA-p3 Pica bypass in cases of high-riding caudal loops or aberrant anatomy is to free the p1 Pica, transpose it away from the lower cranial nerves, and perform an end-to-end OA-p1 Pica bypass instead.
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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, 2019Co-Authors: Sirin Gandhi, Justin R Mascitelli, Douglas A Hardesty, Michael T LawtonAbstract: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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intracranial to intracranial bypass for posterior inferior cerebellar artery aneurysms options technical challenges and results in 35 patients
Journal of Neurosurgery, 2016Co-Authors: Adib A Abla, Cameron M Mcdougall, Jonathan D Breshears, Michael T LawtonAbstract: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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posterior inferior cerebellar artery reimplantation buffer lengths perforator anatomy and technical limitations
Journal of Neurosurgery, 2016Co-Authors: Ali Tayebi Meybodi, Michael T Lawton, Xuequan Feng, Arnau BenetAbstract:OBJECTIVE Reimplantation of the posterior inferior cerebellar artery (Pica) to the vertebral artery (VA) is a safe and effective bypass option after deliberate Pica sacrifice during the treatment of nonsaccular and dissecting aneurysms at this location. However, the anatomy and limitations of this technique have not been studied. The goal of this study was to define the surgical anatomy and buffer lengths specific to the proximal segment of the Pica related to 2 variations of Pica reimplantation: 1) reimplantation "along-VA" (simulating a dissecting VA aneurysm), and 2) reimplantation "across-VA" (simulating a nonclippable, proximal Pica aneurysm). METHODS Ten cadaver heads (20 sides) were prepared for surgical simulation. Twenty far-lateral approaches were performed. The Pica was mobilized and reimplanted onto the VA according to 2 different paradigms: 1) transposition along the axis of the VA (along-VA) to simulate a dissecting VA, and 2) transposition perpendicular to the axis of the VA (across-VA) to simulate a nonclippable, proximal Pica aneurysm. The buffer lengths provided by mobilization of the artery in each paradigm were measured and the anatomy of perforator branching on the proximal Picas was analyzed. RESULTS The Pica was reimplanted in all surgical simulations. The most common perforating artery on the P1 and P2 segments was the short circumflex type. No direct perforator was found on the P1 segment. The mean buffer length with reimplantation along the VA axis was 13.43 ± 4.61 mm, and it was 6.97 ± 4.04 mm with reimplantation across the VA. The Pica was less maneuverable when it was reimplanted across the VA, due to perforator branches of the Pica (P3 segment). CONCLUSIONS The buffer lengths measured in this study describe the limitations of Pica reimplantation as a revascularization procedure for nonsaccular aneurysms in this location. Pica reimplantation is a revascularization option for dissecting VA aneurysms incorporating the Pica origin that are < 13 mm in length, and for nonsaccular proximal Pica aneurysms that are < 6 mm in diameter. The final decision to reimplant the Pica depends on careful inspection of perforator anatomy that is not visible preoperatively on angiography, as well as an assessment of technical difficulty intraoperatively.
Akira Ogawa - One of the best experts on this subject based on the ideXlab platform.
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treatment of vertebral artery aneurysms with transposition of the posterior inferior cerebellar artery to the vertebral artery combined with parent artery occlusion technical note
Journal of Neurosurgery, 2006Co-Authors: Kuniaki Ogasawara, Yoshitaka Kubo, Nobuhiko Tomitsuka, Masayuki Sasoh, Yasunari Otawara, Hiroshi Arai, Akira OgawaAbstract:The authors describe transposition of the posterior inferior cerebellar artery (Pica) to the vertebral artery (VA) combined with parent artery occlusion for the treatment of VA aneurysms in cases in which a clip could not be applied because of the origin of the ipsilateral Pica. The aneurysm is trapped through a lower lateral suboccipital craniectomy. The Pica is then cut just distal to the aneurysm, and the Pica and VA proximal to the aneurysm are anastomosed in an end-to-end or end-to-side fashion. The surgical procedure was successfully performed in two patients, each of whom had hypoplastic occipital arteries (OAs). The Pica contralateral to the lesion was hypoplastic in one patient and distant to the ipsilateral Pica in the other patient. Mild transient dysphagia developed postoperatively in one patient due to glossopharyngeal and vagus nerve palsy, and the other patient had an uneventful postoperative course. In both patients, postoperative cerebral angiography demonstrated good patency of the transposed Pica. These results show that transposition of the Pica to the VA is a useful procedure for the reconstruction of the Pica when parent artery occlusion is necessary to exclude a VA aneurysm involving the origin of the Pica and when OA-Pica anastomosis or Pica-Pica anastomosis cannot be performed.
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treatment of vertebral artery aneurysms with posterior inferior cerebellar artery posterior inferior cerebellar artery anastomosis combined with parent artery occlusion
Surgical Neurology, 2004Co-Authors: Kuniaki Ogasawara, Yoshitaka Kubo, Yasunari Otawara, Shunsuke Kakino, Nobuhiko Tomizuka, Michiyasu Suzuki, Akira OgawaAbstract:Abstract Background In patients with aneurysms that involve the origin of the posterior inferior cerebellar artery (Pica) and require occlusion of the vertebral artery (VA), revascularization of the Pica is commonly performed. We present six patients with dissecting VA aneurysms who underwent Pica-Pica anastomosis combined with parent artery occlusion. Methods After a lower lateral suboccipital craniectomy and partial resection of the jugular tubercle, anastomoses were performed in a side-to-side fashion at the posterior medullary segment of the Pica. The VA was subsequently occluded by clipping proximal and distal to the aneurysm, and the Pica was occluded by clipping distal to the aneurysm. Results Postoperative cerebral angiography demonstrated patency of the anastomosis and regression of the aneurysm in five of six patients. The remaining patient experienced hemorrhage from contralateral VA dissection and subsequently died. One patient experienced myopathy of the lower extremities secondary to intraoperative fixed board compression and developed permanent lower extremity muscular weakness. The remaining four cases experienced no new neurologic deficits. Conclusion Pica-Pica anastomosis is a useful procedure for reconstruction of the Pica when parent vessel occlusion or trapping is necessary to exclude a VA aneurysm involving the origin of the Pica.
Sera L Young - One of the best experts on this subject based on the ideXlab platform.
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Pica is prevalent and strongly associated with iron deficiency among hispanic pregnant women living in the united states
Appetite, 2018Co-Authors: Lia C H Fernald, Sera L Young, Aditi Roy, Elena FuentesafflickAbstract:Abstract Introduction Anecdotal evidence suggests that Pica occurs among Hispanic women in the United States, especially during pregnancy. However, the prevalence and socio-demographic and biological factors associated with Pica in this population have not been adequately identified. Methods Trained, bilingual study personnel conducted structured interviews at public health clinics in Salinas Valley, California with 187 pregnant Hispanic women in their 2nd or 3rd trimesters of pregnancy. Hemoglobin was measured using Hemocue; concentrations of transferrin receptor (TfR) and alpha-1 acid glycoprotein (AGP) were measured in dried blood spots. Multivariable stepwise regression analyses were conducted with Pica during pregnancy as the dependent variable and individual- and family-level factors as independent variables to identify significant associations. Additionally, multivariable models were built to explore the associations between Pica and iron status (iron deficiency and anemia). Results Half of all participants (51.3%) had ever engaged in Pica, and 37.6% had done so during the current pregnancy. Pica substances included large quantities of ice, frost, raw starches, and various earthen items. Pica during the current pregnancy was significantly associated with higher TfR concentrations [OR: 1.29; 95% CI: 1.11, 1.51] indicative of low iron stores and greater food insecurity [OR: 1.20, 95% CI: 1.03, 1.40]. Women who engaged in Pica during the current pregnancy were more likely to be iron deficient [adjusted OR: 2.58; 95% CI: 1.19, 5.60], but not anemic [adjusted OR: 1.40; 0.60, 3.23]. Conclusions Among pregnant Hispanic women, Pica was prevalent and strongly associated with iron deficiency and food insecurity. Clinicians should screen for Pica during pregnancy in Hispanic populations, and future studies should elucidate the underlying etiology and consequences of engaging in Pica during pregnancy.
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Pica during pregnancy among mexican born women a formative study
Maternal and Child Nutrition, 2015Co-Authors: Janice Lin, Luisa Temple, Celina Trujillo, Fabiola Mejiarodriquez, Lisa G Rosas, Lia C H Fernald, Sera L YoungAbstract:Although Pica, the craving and purposive consumption of non-food substances, is common among many populations, especially during pregnancy, the health consequences are not well understood. Further, very little is known about Pica among Mexican populations in the United States and Mexico. Therefore, we conducted formative research to understand Pica in this understudied population. Our objectives were to identify the frequency and types of Pica behaviours, to understand perceived aetiologies and consequences of Pica and to ascertain if the behaviour was common enough to warrant a larger study. We held nine focus group discussions (three in the Salinas Valley, California; six in Xoxocotla, Morelos, Mexico) with 76 Mexican-born women who were currently pregnant or had delivered within the past 2 years. Earth, adobe, bean stones and ice were the most commonly reported Pica substances. Twenty-eight of the 76 participants (37%) reported ever engaging in Pica; 22 participants (29%) reported doing so during pregnancy. The proportion of women reporting Pica in the United States and Mexico was 43% and 34%, respectively. Women attributed Pica to the overwhelming organoleptic appeal of Pica substances (especially smell and texture) and to micronutrient deficiencies. Perceived consequences of unfulfilled Pica cravings were birthmarks or fetal loss; fulfilled Pica cravings were also thought to be generally harmful to the mother or child, with several women specifying toxic lead, pesticides or ‘worms’. In sum, Pica among Mexican women is common enough to warrant a larger epidemiologic study of its sociodemographic correlates and physiological consequences.
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a meta analysis of Pica and micronutrient status
American Journal of Human Biology, 2015Co-Authors: Diana Miao, Sera L Young, Christopher D GoldenAbstract:Objectives Pica is the craving for and consumption of nonfood items, including the ingestion of earth (geophagy), raw starch (amylophagy), and ice (pagophagy). Pica has long been associated with micronutrient deficiencies, but the strength of this relationship is unclear. We aimed to evaluate the association between Pica behavior and the risk of being anemic or having low hemoglobin (Hb), hematocrit (Hct), or plasma zinc (Zn) concentrations. Methods We systematically reviewed studies in which micronutrient levels were reported by Pica status. We calculated the pooled odds ratio for anemia or weighted mean difference in Hb, Hct, or Zn concentrations between groups practicing or not practicing Pica behaviors. Results Forty-three studies including 6,407 individuals with Pica behaviors and 10,277 controls were identified. Pica was associated with 2.35 times greater odds of anemia (95% CI: 1.94–2.85, P < 0.001), lower Hb concentration (−0.65 g/dl, 95% CI: −0.83 to −0.48 g/dl, P < 0.001), lower Hct concentration (−1.15%, 95% CI: −1.61 to −0.70%, P < 0.001), and lower Zn concentration (−34.3 μg/dl, 95% CI: −59.58 to −9.02 μg/dl, P = 0.008). Statistical significance persisted after excluding outliers and in subgroup analyses by Pica type and life stage. Conclusion Pica is significantly associated with increased risk for anemia and low Hb, Hct, and plasma Zn. Although the direction of the causal relationship between Pica and micronutrient deficiency is unknown, the magnitude of these relationships is comparable to other well-recognized causes of micronutrient deficiencies. Pica warrants greater public health attention; specifically the potential physiological mechanisms underpinning the relationship between Pica and micronutrient deficiencies merit further study. Am. J. Hum. Biol. 27:84–93, 2015. © 2014 Wiley Periodicals, Inc.
Cameron G Mcdougall - One of the best experts on this subject based on the ideXlab platform.
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posterior inferior cerebellar artery patency after flow diverting stent treatment
American Journal of Neuroradiology, 2016Co-Authors: Michael R Levitt, Min S Park, Felipe C Albuquerque, Karam Moon, Mohammad Yashar S Kalani, Cameron G McdougallAbstract:BACKGROUND AND PURPOSE: The rate of Pica occlusion after flow-diverting stent placement for vertebral and vertebrobasilar artery aneurysms is not known. The purpose of this study is to determine the medium-term rate of Pica patency and risk factors for occlusion after such aneurysm treatment. MATERIALS AND METHODS: Patients were identified who had vertebral or vertebrobasilar artery aneurysms and who were treated by placing a flow-diverting stent across the Pica ostium. Demographic and procedural factors associated with stent placement were recorded. Patency of the Pica was evaluated immediately after stent placement and on follow-up angiography. RESULTS: Thirteen patients with vertebral or vertebrobasilar artery aneurysms were treated in the study period, of whom 4 presented with subarachnoid hemorrhage. The average number of devices that spanned the Pica ostium was 1.77 (range, 1–3), with no immediate Pica occlusions. There were no postoperative strokes in the treated Pica territory, although there was 1 contralateral Pica-territory stroke of unclear etiology without clinical sequelae. In 11 patients with follow-up angiography at a mean of 10.6 months (range, 0.67–27.9 months), the Pica patency rate remained 100%. CONCLUSIONS: Flow-diverting stent placement across the Pica ostium in the treatment of vertebral and vertebrobasilar artery aneurysms may not result in immediate or midterm Pica occlusion.
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technical considerations in the endovascular management of aneurysms of the posterior inferior cerebellar artery
Operative Neurosurgery, 2012Co-Authors: Webster R Crowley, Felipe C Albuquerque, Andrew F Ducruet, Richard W Williamson, Cameron G McdougallAbstract:BACKGROUND Aneurysms of the posterior inferior cerebellar artery (Pica) are rare, comprising 0.5% to 3% of intracranial aneurysms. Because their anatomic location relative to the Pica origin is variable, several endovascular techniques are used in their management. OBJECTIVE To evaluate and discuss endovascular techniques for the treatment of Pica aneurysms. METHODS We analyzed our prospectively maintained database to identify Pica aneurysms treated over a 12-year period from 1999 to 2011. RESULTS Twenty patients were assessed angiographically for endovascular treatment. Treatment was successfully performed in 17, but 3 were deemed unsuitable and were referred for surgery. Patients ranged in age from 15 to 82 years (mean, 60.5); 85% (17/20) were women. Thirteen (65%) presented with subarachnoid hemorrhage, and 3 (15%) had been previously treated surgically. Although the aneurysms were located at the Pica origin in 13 (65%), their involvement with the Pica and vertebral artery was variable. Some arose distinctly from the origin, and others incorporated the Pica itself. Five patients were treated for distal Pica aneurysms. Treatment techniques included direct coiling, vertebral artery balloon remodeling with coiling, Pica balloon remodeling with coiling, and parent vessel sacrifice of Pica with either coiling or glue embolization. Complete occlusion was initially achieved in 11 of 17 patients. Of the 6 remaining patients, 3 improved to complete occlusion at follow-up, 2 underwent re-treatment, and 1 remained stable. No patient experienced posttreatment hemorrhage. CONCLUSION A variety of endovascular techniques are required for the management of Pica aneurysms. Specific techniques vary according to the location of the aneurysm in relation to the Pica origin, distal course of the artery, and the vertebral artery. ABBREVIATIONS BRAT, Barrow Ruptured Aneurysm TrialmRS, modified Rankin scorenBCA, n-butyl cyanoacrylatePica, posterior inferior cerebellar arterySAH, subarachnoid hemorrhageVA, vertebral artery.
Adib A Abla - One of the best experts on this subject based on the ideXlab platform.
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revascularization of the anterior inferior cerebellar artery using extracranial and intracranial donors a morphometric cadaveric study
World Neurosurgery, 2019Co-Authors: Alex De Vilalta, Adib A Abla, Ioannis Kournoutas, Pablo Lopez Ojeda, Andreu Gabarros Canals, Vera Vigo, Caleb Rutledge, Ricky Chae, Roberto Rodriguez RubioAbstract:Introduction Anterior inferior cerebellar artery (AICA) aneurysms are rare, accounting for 0.2%–1.3% of all intracranial aneurysms. The standard treatment is often endovascular embolization or neck clipping; however, sacrifice of the parent vessel is sometimes necessary. Addition of revascularization procedures is a subject of controversy. The occipital artery (OA) has been used as a donor for bypass, but recently there has been a trend toward intracranial-intracranial approaches. The posterior inferior cerebellar artery (Pica)-AICA side-to-side bypass may serve as a safe alternative. Objective To characterize the Pica-AICA side-to-side bypass and the OA-AICA end-to-side bypass and review the literature relevant to AICA revascularization. Methods We performed a far-lateral approach on 12 cadaveric specimens and analyzed the regional anatomy. On this basis, we performed either an OA-AICA or a Pica-AICA bypass and took morphometric measurements relevant to the technique. Results Pica-AICA bypass was successful in 6/12 specimens. The length of the flocculopeduncular segment was 42.6 ± 15.8 mm in the specimens in which the bypass was feasible and 26.2 ± 7.2 mm in those in which the bypass was not feasible (P = 0.04). Mean distance between AICA and Pica was 5.3 ± 4 mm in the specimens in which side-to-side bypass was feasible and 11.6 ± 4.2 mm in the specimens in which it was not (P = 0.02). OA-AICA end-to-side bypass was feasible in all the specimens (75% in the flocculopeduncular segment; 25% in the cortical segment). Conclusions This is the first cadaveric study analyzing the Pica-AICA side-to-side bypass for AICA revascularization. Our analyses provide evidence for the feasibility of this bypass and document the anatomic variations that may indicate its use.
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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, 2016Co-Authors: Adib A Abla, Cameron M Mcdougall, Jonathan D Breshears, Michael T LawtonAbstract: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.
