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

2018 ◽  
Vol 16 (4) ◽  
pp. E119-E120 ◽  
Author(s):  
Sirin Gandhi ◽  
Justin Mascitelli ◽  
Douglas Hardesty ◽  
Michael T Lawton

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

2002 ◽  
Vol 97 (1) ◽  
pp. 219-223 ◽  
Author(s):  
G. Michael Lemole ◽  
Jeffrey Henn ◽  
Sam Javedan ◽  
Vivek Deshmukh ◽  
Robert F. Spetzler

✓ 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.


2020 ◽  
Vol 19 (3) ◽  
pp. E311-E312
Author(s):  
Justin R Mascitelli ◽  
Sirin Gandhi ◽  
Jacob F Baranoski ◽  
Michael J Lang ◽  
Michael T Lawton

Abstract In situ bypasses to the anterior inferior cerebellar artery (AICA) are unusual because, with only one artery in the cerebellopontine angle (CPA), no natural intracranial donors parallel its course. In rare cases, the posterior inferior cerebellar artery (PICA) may have the tortuosity or redundancy to be mobilized to the AICA to serve as a donor. This video demonstrates this p3 PICA-to-a3 AICA in situ side-to-side bypass. A 75-yr-old woman presented with ataxia and hemiparesis from a large thrombotic right AICA aneurysm compressing the brainstem. Strategy consisted of bypass, trapping, and brainstem decompression. Written informed consent for surgery was obtained from the patient. A hockey-stick incision was made to harvest the occipital artery as a backup donor, but its diminutive caliber precluded its use. The bypass was performed through an extended retrosigmoid craniotomy. The aneurysm was trapped completely and thrombectomized to relieve the pontine mass effect. Indocyanine green videoangiography confirmed patency of the bypass, retrograde filling of the AICA to supply pontine perforators, and no residual aneurysmal filling. This unusual in situ bypass is possible when redundancy of the AICA and PICA allow their approximation in the CPA. The anastomosis is performed lateral to the lower cranial nerves in a relatively open and superficial plane. The extended retrosigmoid approach provides adequate exposure for both the bypass and aneurysm trapping. In situ AICA-PICA bypass enables anterograde and retrograde AICA revascularization with side-to-side anastomosis. The occipital artery-to-AICA bypass and the V3 vertebral artery-to-AICA interpositional bypass are alternatives when intracranial anatomy is unfavorable for this in situ bypass.1–6 Used with permission from Barrow Neurological Institute, Phoenix, Arizona.


2020 ◽  
Vol 19 (4) ◽  
pp. E423-E423
Author(s):  
Sirin Gandhi ◽  
Justin R Mascitelli ◽  
Claudio Cavallo ◽  
Ali Tayebi Meybodi ◽  
Michael T Lawton

Abstract Lateral medullary arteriovenous malformations (AVMs) are located in the pia on the lateral medullary surface.1 They are supplied by arterial feeders from the V4 segment of the vertebral artery or posterior inferior cerebellar artery. A 64-yr-old man presented with leg spasms and progressively worsening gait. Angiography demonstrated a lateral medullary AVM. Patient consent was obtained for the surgical treatment of this lesion. Owing to its eloquent location, an occlusion in situ was performed without resection.1,2 This technique relies on the interruption of the arterial blood supply and occlusion of the draining vein to occlude the AVM. Intraoperative neurophysiological monitoring of motor and somatosensory evoked potentials was used, and the elimination of arteriovenous shunt flow was confirmed using indocyanine green videoangiography. Occlusion in situ preserves the flow to the delicate brainstem perforators and is safer than resection in selected cases like this one. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.


2017 ◽  
Vol 126 (2) ◽  
pp. 634-644 ◽  
Author(s):  
Hitoshi Fukuda ◽  
Alexander I. Evins ◽  
Koichi Iwasaki ◽  
Itaro Hattori ◽  
Kenichi Murao ◽  
...  

OBJECTIVE Occipital artery–posterior inferior cerebellar artery (OA-PICA) bypass is a technically challenging procedure for posterior fossa revascularization. The caudal loop of the PICA is considered the optimal site for OA-PICA anastomosis, however its absence can increase the technical difficulty associated with this procedure. The use of the far-lateral approach for accessing alternative anastomosis sites in OA-PICA bypass in patients with absent or unavailable caudal loops of PICA is evaluated. METHODS A morphometric analysis of OA-PICA bypass with anastomosis on each segment of the PICA was performed on 5 cadaveric specimens through the conventional midline foramen magnum and far-lateral approaches. The difficulty level associated with anastomoses at each segment was qualitatively assessed in each approach for exposure and maneuverability by multiple surgeons. A series of 8 patients who underwent OA-PICA bypass for hemodynamic ischemia or ruptured dissecting posterior fossa aneurysms are additionally reviewed and described, and the clinical significance of the caudal loop of PICA is discussed. RESULTS Anastomosis on the caudal loop could be performed more superficially than on any other segment (p < 0.001). A far-lateral approach up to the medial border of the posterior condylar canal provided a 13.5 ± 2.2–mm wider corridor than the conventional midline foramen magnum approach, facilitating access to alternative anastomosis sites. The far-lateral approach was successfully used for OA-PICA bypass in 3 clinical cases whose caudal loops were absent, whereas the midline foramen magnum approach provided sufficient exposure for caudal loop bypass in the remaining 5 cases. CONCLUSIONS The absence of the caudal loop of the PICA is a major contributing factor to the technical difficulty of OA-PICA bypass. The far-lateral approach is a useful surgical option for OA-PICA bypass when the caudal loop of the PICA is unavailable.


2006 ◽  
Vol 105 (5) ◽  
pp. 781-784 ◽  
Author(s):  
Kuniaki Ogasawara ◽  
Yoshitaka Kubo ◽  
Nobuhiko Tomitsuka ◽  
Masayuki Sasoh ◽  
Yasunari Otawara ◽  
...  

✓ 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.


2017 ◽  
Vol 14 (4) ◽  
pp. 422-431 ◽  
Author(s):  
Alessandro Narducci ◽  
Ran Xu ◽  
Peter Vajkoczy

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.


2017 ◽  
Vol 14 (5) ◽  
pp. 563-571 ◽  
Author(s):  
Ken Matsushima ◽  
Satoshi Matsuo ◽  
Noritaka Komune ◽  
Michihiro Kohno ◽  
J Richard Lister

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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