Far Lateral Approach for Clipping of a Posterior Inferior Cerebellar Artery Aneurysm

Abstract Objectives To describe a far lateral approach for microsurgical clipping of a ruptured posterior inferior cerebellar artery (PICA) aneurysm involving the hypoglossal nerve, with emphasis on the microsurgical anatomy, and technique. Design A far lateral craniotomy is performed in the lateral decubitus position and the transverse and sigmoid sinuses were exposed. After opening the dura, sutures are placed to allow gentle mobilization of the sinuses. The ipsilateral cerebellar tonsil is mobilized and the PICA is followed to its junction with the vertebral artery. Hypoglossal nerve rootlets are draped over the dome of the aneurysm. Mobilization of the PICA and the hypoglossal nerve away from the lateral medulla allows microsurgical clipping of the aneurysm neck. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The senior authors performed the surgery. The video was edited by Drs. V.N. and J.B. Chart review and literature review were performed by Drs. W.M. and J.B. Outcome Measures Outcome was assessed with successful clip occlusion and postoperative neurological function. Results There was complete clip occlusion of the PICA aneurysm with no postoperative neurological deficits. The patient was discharged home after an uneventful hospital course. Conclusion The far lateral approach provides an adequate corridor to the ventrolateral brainstem for microsurgical treatment of PICA aneurysms. An adequate understanding of the relevant microsurgical anatomy is the key to safe and effective clipping in this region.The link to the video can be found at: https://youtu.be/yhjKRIG5H74.

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Microsurgical anatomy of the posterior spinal artery via a far-lateral transcondylar approach

Journal of Neurosurgery Spine ◽

10.3171/2008.12.spine08289 ◽

2009 ◽

Vol 10 (3) ◽

pp. 228-233 ◽

Cited By ~ 11

Author(s):

Hakan Seçkin ◽

Özkan Ateş ◽

Andrew M. Bauer ◽

Mustafa K. Başkaya

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Lateral Approach ◽

Microsurgical Anatomy ◽

Posterior Spinal Artery ◽

Transcondylar Approach ◽

Cerebellar Artery ◽

Far Lateral Approach ◽

Close Proximity ◽

Far Lateral ◽

Clinically Significant

Object The posterior spinal artery (PSA) is a clinically significant vessel that may frequently be encountered during the far-lateral transcondylar approach. There have been a limited number of reports on the specific origin of the PSA in the literature. The aim of this study was to demonstrate the origin of the PSA. Methods Thirteen cadaveric heads (26 sides) were injected with colored silicon. A bilateral far-lateral transcondylar approach was performed on each side. In every specimen the site of the origin of the PSAs, as well as their course, branching pattern and anastomoses, external diameters, and neighboring vascular and nervous structures were recorded. Microanatomical dissections were performed using the surgical microscope. In addition, 8 surgical cases in which the far-lateral approach was used were collected prospectively to record the course and origin of the PSA. Altogether, a total of 34 sides were analyzed for their PSA origin and course. Results In the cadaveric specimens, the PSA was found to originate from the vertebral artery (VA) in 25 sides (96%). In 13 specimens (50%) the PSA originated from the V4 segment of the VA intradurally. In 12 specimens (46%) the PSA originated from the V3 segment of the VA extradurally. In 1 specimen (4%), in whom the posterior inferior cerebellar artery (PICA) had an early origin from the VA extradurally at the C-1 level, the PSA originated from the PICA. Of the 8 surgical cases, 2 patients had extradural origin of the PSA from the V3 segment of the VA, whereas 6 patients had intradural origin of the PSA from the V4 segment. Conclusions Although the usual origin of the PSA is from the VA either intra- or extradurally, its origin is closely related to the origin of the PICA. The PSA originates from the PICA in cases in which the PICA originates extradurally from the VA. In the far-lateral transcondylar approach, the dura is opened in close proximity to the VA. Knowledge of the origin and course of the PSA is critically important when executing the far-lateral approach to avoid its injury.

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Contralateral far-lateral approach for clipping of a ruptured vertebral artery–posterior inferior cerebellar artery aneurysm

Neurosurgical FOCUS ◽

10.3171/foc.2008.25.12.e9 ◽

2008 ◽

Vol 25 (6) ◽

pp. E9 ◽

Cited By ~ 11

Author(s):

Taryn McFadden Bragg ◽

Edward A. M. Duckworth

Keyword(s):

Computed Tomography ◽

Vertebral Artery ◽

Posterior Inferior Cerebellar Artery ◽

Artery Aneurysm ◽

Lateral Approach ◽

Cerebellar Artery ◽

Far Lateral Approach ◽

Far Lateral ◽

The Right ◽

Pica Aneurysms

Numerous nuanced approaches have been used to access posterior inferior cerebellar artery (PICA) aneurysms for microsurgical clipping. The authors report the case of a patient with a right vertebral artery (VA)–PICA aneurysm that was reached via a contralateral far-lateral approach. The wide-necked saccular/fusiform aneurysm arose from the lateral aspect of the right V4 segment just proximal to the PICA origin, anterior to the jugular tubercle at the level of the hypoglossal canal. Computed tomography angiograms demonstrated the size and configuration of the aneurysm, and 3D reconstructions revealed the tortuosity of the right VA, defining its location just left of the midline adjacent to the lower clivus. A contralateral far-lateral approach to VA–PICA aneurysms should be considered when aneurysms cross the midline. Computed tomography angiography with volume rendering and interactive software capabilities can help identify the relationship of such an aneurysm to an individual's particular skull base osseous anatomy and is paramount in selecting the optimal microsurgical approach.

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Treatment of an Anterior Inferior Cerebellar Artery Aneurysm With Microsurgical Trapping and In Situ Posterior Inferior Cerebellar Artery to Anterior Inferior Cerebellar Artery Bypass: Case Report

Operative Neurosurgery ◽

10.1093/ons/opx275 ◽

2017 ◽

Vol 15 (4) ◽

pp. 418-424 ◽

Cited By ~ 6

Author(s):

Bryan S Lee ◽

Alex M Witek ◽

Nina Z Moore ◽

Mark D Bain

Keyword(s):

Artery Bypass ◽

Posterior Inferior Cerebellar Artery ◽

Significant Risk ◽

Artery Aneurysm ◽

Lateral Approach ◽

Anterior Inferior Cerebellar Artery ◽

Parent Vessel ◽

Cerebellar Artery ◽

Far Lateral Approach

Abstract BACKGROUND Anterior inferior cerebellar artery (AICA) aneurysms are rare lesions whose treatment can involve microsurgical and/or endovascular techniques. Such treatment can be challenging and may carry a significant risk of neurological morbidity. OBJECTIVE To demonstrate a case involving a complex AICA aneurysm that was treated with a unique microsurgical approach involving trapping the aneurysm and performing in Situ bypass from the posterior inferior cerebellar artery (PICA) to the distal AICA. The nuances of AICA aneurysms and revascularization strategies are discussed. METHODS The aneurysm and the distal segments of AICA and PICA were exposed with a retrosigmoid and far lateral approach. A side-to-side anastomosis was performed between the adjacent caudal loops of PICA and AICA. The AICA aneurysm was then treated by trapping the aneurysm-bearing segment of the parent vessel between 2 clips. RESULTS A postoperative angiogram demonstrated a patent PICA-AICA bypass and complete occlusion of the AICA aneurysm. There were no complications, and the patient made an excellent recovery. CONCLUSION The combination of parent vessel sacrifice and bypass remains an excellent option for certain difficult-to-treat aneurysms. This case involving PICA-AICA bypass to treat an AICA aneurysm serves as an example of the neurosurgeon's ability to develop unique solutions that take advantage of individual anatomy.

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The role of alternative anastomosis sites in occipital artery–posterior inferior cerebellar artery bypass in the absence of the caudal loop using the far-lateral approach

Journal of Neurosurgery ◽

10.3171/2015.11.jns151385 ◽

2017 ◽

Vol 126 (2) ◽

pp. 634-644 ◽

Cited By ~ 3

Author(s):

Hitoshi Fukuda ◽

Alexander I. Evins ◽

Koichi Iwasaki ◽

Itaro Hattori ◽

Kenichi Murao ◽

...

Keyword(s):

Posterior Fossa ◽

Posterior Inferior Cerebellar Artery ◽

Technical Difficulty ◽

Foramen Magnum ◽

Lateral Approach ◽

Difficulty Level ◽

Occipital Artery ◽

Cerebellar Artery ◽

Far Lateral Approach ◽

Far Lateral

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.

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Technical strategies to approach aneurysms of the vertebral and posterior inferior cerebellar arteries

Neurosurgical FOCUS ◽

10.3171/foc.2005.19.2.5 ◽

2005 ◽

Vol 19 (2) ◽

pp. 1-5 ◽

Cited By ~ 16

Author(s):

Niklaus Krayenbühl ◽

Carlos A. Guerrero ◽

Ali F. Krisht

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Cranial Nerves ◽

Foramen Magnum ◽

Lateral Approach ◽

Anatomical Location ◽

Microsurgical Anatomy ◽

Far Lateral Approach ◽

Far Lateral ◽

Pica Aneurysms ◽

Lower Cranial Nerves

Object Aneurysms of the vertebral artery (VA) and proximal posterior inferior cerebellar artery (PICA) are rare and challenging lesions, as they are located in front of the brainstem and surrounded by the lower cranial nerves. Many different approaches have been described for their treatment, and have yielded different results. With the use of different examples of lesions, the authors describe their surgical strategy in the management of VA and PICA aneurysms. Methods The far-lateral approach was used, and the potential of its different extensions according to the specific anatomical location and configuration of different types of aneurysms is emphasized. Conclusions With the present knowledge of the microsurgical anatomy in the region of the foramen magnum, the far-lateral approach can be tailored to the specific anatomical and morphological configuration of an aneurysm in this region with good surgical results.

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Far-lateral approach for surgical treatment of fusiform PICA aneurysm

Neurosurgical FOCUS ◽

10.3171/2015.v1.focus14549 ◽

2015 ◽

Vol 38 (videosuppl1) ◽

pp. Video10 ◽

Cited By ~ 2

Author(s):

William T. Couldwell ◽

Jayson A. Neil

Keyword(s):

Evoked Potential ◽

Posterior Inferior Cerebellar Artery ◽

Motor Evoked Potential ◽

Lateral Approach ◽

Cerebellar Artery ◽

Far Lateral Approach ◽

Vessel Patency ◽

Far Lateral ◽

Evoked Potential Monitoring ◽

Pica Aneurysms

Ruptured fusiform posterior inferior cerebellar artery (PICA) aneurysms can be technically challenging lesions. Surgeons must be ready to employ a variety of strategies in the successful treatment of these aneurysms. Strategies include complex clip techniques including clip-wrapping or trapping and revascularization. The case presented here is of a man with subarachnoid hemorrhage from a fusiform ruptured PICA aneurysm. The technique demonstrated is a far-lateral approach and a clip-wrap technique using muslin gauze. The patient was given aspirin preoperatively in preparation for possible occipital–PICA bypass if direct repair was not feasible. It is the authors' preference to perform direct vessel repair as a primary goal and use bypass techniques when this is not possible. Vessel patency was evaluated after clip-wrapping using intraoperative Doppler. Intraoperative somatosensory and motor evoked potential monitoring is used in such cases. The patient recovered well.The video can be found here: http://youtu.be/iwLqufH47Ds.

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Trapping and P2-P3 Posterior Inferior Cerebellar Artery Reanastomosis for Treatment of a Ruptured Fusiform Aneurysm: Application of Fourth-Generation Technique: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opab338 ◽

2021 ◽

Author(s):

Tyler T Lazaro ◽

Visish M Srinivasan ◽

Patrick C Cotton ◽

Jacob Cherian ◽

Jeremiah N Johnson

Keyword(s):

Posterior Inferior Cerebellar Artery ◽

Lateral Approach ◽

Fourth Generation ◽

Cerebellar Artery ◽

Far Lateral Approach ◽

Close Proximity ◽

Far Lateral ◽

Pica Aneurysms ◽

Distal Artery

Abstract Aneurysms of the posterior inferior cerebellar artery (PICA) represent the second most common posterior circulation aneurysm and commonly have complex morphology. Various bypass options exist for PICA aneurysms,1-6 depending on their location relative to brainstem perforators and the vertebral artery, and the presence of nearby donor arteries. We present a case of a man in his late 40s who presented with 3 d of severe headache. He was found to have a fusiform right P2-segment PICA aneurysm. Preoperative angiogram demonstrated the aneurysm and a redundant P3 caudal loop that came in close proximity to the healthy P2 segment proximal to the aneurysm. The risks and benefits of the procedure were discussed with the patient, and they consented for a right far lateral approach craniotomy with partial condylectomy for trapping of the aneurysm with bypass. The aneurysm was trapped proximally and distally. The P3 was transected just distal to the aneurysm and brought toward the proximal P2 segment, facilitated by a lack of perforators on this redundant distal artery. An end-to-side anastomosis was performed. Postoperative angiogram demonstrated exclusion of the aneurysm and patent bypass. The patient recovered well and remained without any neurological deficit at 6-mo follow-up. This case demonstrates the use of a “fourth-generation”5,7,8 bypass technique. These techniques represent the next innovation beyond third-generation intracranial-intracranial bypass. In this type 4B reanastomosis bypass, an unconventional orientation of the arteries was used. Whereas reanastomosis is typically performed end-to-end, the natural course of these arteries and the relatively less-mobile proximal P2 segment made end-to-side the preferred option in this case. Fourth-generation bypass techniques open up more configurations for reanastomosis, using the local anatomy to the surgeon's advantage. The patient consented to the described procedure and consented to the publication of their image.

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Far-Lateral Approach Without Drilling the Occipital Condyle for Vertebral Artery–Posterior Inferior Cerebellar Artery Aneurysms

Neurosurgery ◽

10.1093/neuros/nyw136 ◽

2017 ◽

Vol 81 (2) ◽

pp. 268-274 ◽

Cited By ~ 11

Author(s):

Pablo Seoane ◽

Samuel Kalb ◽

Justin C. Clark ◽

Juan C. Rivas ◽

David S. Xu ◽

...

Keyword(s):

Vertebral Artery ◽

Glasgow Outcome Scale ◽

Posterior Inferior Cerebellar Artery ◽

Lateral Approach ◽

Occipital Condyle ◽

Cerebellar Artery ◽

Far Lateral Approach ◽

Scale Scores ◽

Far Lateral ◽

Pica Aneurysms

Abstract BACKGROUND: The far-lateral transcondylar surgical approach is often used to clip vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms. The role of condyle resection during this approach is controversial. OBJECTIVE: To evaluate patient outcomes in patients with VA–PICA aneurysms in whom drilling the occipital condyle was not necessary. METHODS: Between May 2005 and December 2012, a total of 56 consecutive patients with incidental or ruptured VA–PICA aneurysms underwent surgery with a far-lateral approach without condylar resection. Clinical presentation, surgical reports, presurgery and postsurgery radiological examinations, and clinical follow-up reports were assessed. Anatomic aneurysm location was analyzed through angiography or computed tomography angiography. We compared postsurgical Glasgow Outcome Scale scores, modified Rankin Scale scores, and morbidity in 2 groups: those with aneurysms in the anterior medullary segment and those with aneurysms in the lateral medullary segment. RESULTS: The predominant presentation was subarachnoid hemorrhage in 34 patients (60.7%). Most aneurysms (n = 27 [48.2%]) were located in the lateral medullary segment of the PICA, followed by the anterior medullary segment (n = 25 [44.6%]). Total aneurysm occlusion was achieved in 100% of patients, and bypass techniques were necessary in 3 patients (5.4%). Fifty-two patients (92.8%) had Glasgow Outcome Scale scores of 4 or 5 postsurgery. CONCLUSIONS: A far-lateral approach that leaves the occipital condyle intact is adequate for treating most patients with VA–PICA aneurysms.

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