Unilateral approach for bilateral clipping of posterior communicating artery aneurysms in a hybrid operating room: A technical note.

Bilateral posterior communicating (pComm) artery aneurysms represent only 2% of mirror intracranial aneurysms. Usually, these are surgically approached through bilateral craniotomies for clipping. We present the case of a 50-year-old female presenting with headache and horizontal diplopia. Neurological examination revealed a left oculomotor palsy, with no other neurological deficits. Imaging studies revealed bilateral aneurysmatic lesions in both internal carotid arteries (ICA). A conventional left pterional approach was planned in order to treat the symptomatic aneurysm, and, if deemed feasible, a contralateral clipping through the same approach. The procedure was performed in a hybrid operating room (HOR), performing an intraoperative digital subtraction angiography (DSA) and roadmapping assistance during dissection and clipping. Transoperatively, a post-fixed optic chiasm was identified, with a wide interoptic space, which allowed us to perform the contralateral clipping through a unilateral approach. This technique for clipping bilateral pComm aneurysms can be performed when the proper anatomical features are met.

Evaluación morfológica y variaciones del circulo arterial cerebral: un estudio con material cadavérico en una muestra de población colombianas / Morphological evaluation and variations of the cerebral arterial circle: a study with cadaveric material in a Colombian population sample

RESUMEN: El círculo arterial cerebral (CAC) mencionado también como polígono de Willis es una red de anastomosis vascular situado en la base del cerebro, constituido por ramas de la arteria carótida interna (ACI) y del sistema vertebro-basilar. Este estudio evaluó la morfología de las arterias que conforman el CAC en una muestra de individuos colombianos. Previa canalización de la ACI y de la arteria vertebral (AV), se perfundió con resina poliéster (palatal 85 % y estireno 15 %) los lechos vasculares del CAC de 70 encéfalos extraídos de cadáveres a quienes se les practicó necropsia en el Instituto de Medicina Legal de Bucaramanga, Colombia. La arteria comunicante anterior (ACoA) se observó en 68 encéfalos (97,1 %), con ausencia en 2 de las muestras (2,9 %); en promedio su diámetro fue de 1,91?1,04 mm y su longitud 2,21?0,97 mm respectivamente. Asimismo, se encontró hipoplasia en 6 muestras (8,4 %). La arteria comunicante posterior (ACoP) estuvo ausente en 2 de las muestras (5,7 %); su longitud fue 11,63?2,12 mm, mientras que su calibre fue de 1,21?0,58 mm, siendo ligeramente mayor en el lado derecho, sin diferencias estadísticamente significativas con relación al lado de presentación (p= 0,763). Se encontró hipoplasia de la ACoP en forma bilateral en 19 de las muestras (27,1 %) y unilateral en 15 muestras (21,4 %). En 8 muestras (20 %) de 35 CAC evaluados se observó configuración fetal. La incidencia de hipoplasia de la ACoP y de configuración fetal encontrados en el presente estudio, se ubican en el segmento superior de lo reportado en la literatura. Estas expresiones morfológicas han sido consideradas como coadyuvantes en el desarrollo de accidentes cerebro-vasculares (ACV).

SUMMARY: The cerebral arterial circle (CAC), also referred to as the polygon of Willis is a network of vascular anastomoses located at the base of the brain, consisting of branches of the internal carotid artery (ICA) and the vertebrobasilar system (VBS). This study evaluated the morphology of the arteries forming the CAC in a sample of Colombian individuals. After cannulation of the ICA and the vertebral artery (VA), the vascular beds of the ACC of 70 brains extracted from cadavers at the Institute of Legal Medicine of Bucaramanga, Colombia, were perfused with polyester resin (85 % palatal and 15 % styrene). The anterior communicating artery (ACoA) was observed in 68 brains (97.1 %), with absence in 2 of the samples (2.9 %); on average its diameter was 1.91?1.04mm and its length 2.21?0.97mm respectively. Likewise, hypoplasia was found in 6 samples (8.4 %). The posterior communicating artery (ACoP) was absent in 2 of the samples (5,7 %); its length was 11.63?2.12mm, while its caliber was 1.21?0.58mm, being slightly larger on the right side, with no statistically significant differences in relation to the side of presentation (p= 0.763). Hypoplasia of the ACoP was found bilaterally in 19 of the samples (27.1 %) and unilaterally in 15 samples (21.4 %). Fetal configuration was observed in 8 samples (20 %) of 35 CACs evaluated. The incidence of ACoP hypoplasia and fetal configuration found in the present study are in the upper segment of those reported in the literature. These morphological expressions have been considered as coadjuvants in the development of cerebrovascular accidents (CVA).

Surgery of a Posterior Communicating Artery Aneurysm with Fetal-Type Circulation

Inadvertent occlusion of a fetal-type posterior communicating artery in aneurysm surgery could result in posterior circulation infarction and neurological morbidity. The case of a patient with an unruptured posterior communicating artery aneurysm with lateral projection and a fetal-type posterior communicating artery is presented. The utility of the carotid-oculomotor window as a surgical corridor to safely find the fetaltype posterior communicating artery is discussed.

A oclusão da artéria comunicante posterior do tipo fetal em cirurgia de aneurisma pode resultar em infarto da circulação posterior e morbidade neurológica. Apresentamos o caso de um paciente com aneurisma não roto da artéria comunicante posterior com projeção lateral e uma artéria comunicante posterior do tipo fetal. Discutimos a utilidade da janela carótida-oculomotora como um corredor cirúrgico para encontrar com segurança a artéria comunicante posterior do tipo fetal.

"True" posterior communicating aneurysms: Three cases, three strategies.

BACKGROUND: The authors provide a review of true aneurysms of the posterior communicating artery (PCoA). Three cases admitted in our hospital are presented and discussed as follows. CASE DESCRIPTIONS: First patient is a 51-year-old female presenting with a Fisher II, Hunt-Hess III (headache and confusion) subarachnoid hemorrhage (SAH) from a ruptured true aneurysm of the right PCoA. She underwent a successful ipsilateral pterional craniotomy for aneurysm clipping and was discharged on postoperative day 4 without neurological deficit. Second patient is a 53-year-old female with a Fisher I, Hunt-Hess III (headache, mild hemiparesis) SAH and multiple aneurisms, one from left ophthalmic carotid artery and one (true) from right PCoA. These lesions were approached and successfully treated by a single pterional craniotomy on the left side. The patient was discharged 4 days after surgery, with complete recovery of muscle strength during follow-up. Third patient is a 69-year-old male with a Fisher III, Hunt-Hess III (headache and confusion) SAH, from a true PCoA on the right. He had a left subclavian artery occlusion with flow theft from the right vertebral artery to the left vertebral artery. The patient underwent endovascular treatment with angioplasty and stent placement on the left subclavian artery that resulted in aneurysm occlusion. CONCLUSION: In conclusion, despite their seldom occurrence, true PCoA aneurysms can be successfully treated with different strategies.

[Endovascular coiling of a «true¼ posterior communicating artery aneurysm]. / Tratamiento endovascular de un aneurisma «verdadero¼ de la arteria comunicante posterior.

True posterior communicating artery aneurysms originate exclusively from the wall of this artery and should be differentiated from aneurysms of the posterior communicating segment of the distal carotid artery. As these lesions are rare, their anatomical relationships have been poorly described; likewise, reports concerning their endovascular treatment are extremely rare and the technical aspects poorly detailed. A case of a patient with a true aneurysm of the left posterior communicating artery treated by endovascular coiling is presented. A literature review was also conducted to illustrate the anatomical and technical details relevant to achieving its successful treatment.

The distance between the posterior communicating arteries and their relation to the endoscopic third ventriculostomy in adults: An anatomic study.

BACKGROUND: The diencephalic leaf of the Liliequist's membrane is a continuous structure that should be perforated in the endoscopic third ventriculostomy. Its lateral borders are penetrated by the third cranial nerve and the posterior communicating arteries. The most important complication of endoscopic third ventriculostomy is the vascular injury, such as the posterior communicating artery. The purpose of this study is to measure the distance between posterior communicating arteries located below the third ventricle floor and anterior of the mammillary bodies. METHODS: In this observational prospective study 20 fresh brains from cadavers were utilized to measure the distance between the posterior communicating arteries in April 2008 at the Death Check Unit of our Institution. A digital photograph of the posterior communicating arteries was taken and the distance between the arteries was measured. The measurement was analyzed using descriptive statistics. RESULTS: In the descriptive analysis of the 20 specimens, the posterior communicating arteries distance was 9 to 18.9 mm, a mean of 12.5 mm, median of 12.2 mm, standard deviation of 2.3 mm. CONCLUSION: The detailed knowledge of vascular structures involved in the endoscopic third ventriculostomy as to the posterior communicating arteries distance provides a safe lateral vascular border when performing such procedure.

Biometría de las Arterias Comunicantes Posteriores y Cerebrales Posteriores en su Segmento Precomunicante (P1) en el Círculo Arterial del Cerebro (Willis) / Biometrics of the Posterior Communicating Artery and the Posterior Cerebral Artery in its Precommunicating Segment (P1) of the Arterial Circle of Brain (Willis)

El conocimiento anatómico y clínico preciso del círculo arterial del cerebro, se hace cada vez más necesario, por la compleja relación neural que presentan las diversas arterias que entran en su formación y además por su gran variabilidad. Utilizamos 36 encéfalos humanos frescos, provenientes de especímenes autopsiados adultos, cuyos datos bioantropológicos fueron previamente registrados. El calibre de las aa. comunicantes posteriores fue, en promedio, de 1,08 mm (DE 0,45 ) en ambos lados y su longitud de 17,51 mm( DE 7,9) en el lado derecho y de 16,9 mm (DE 8,0 ) en el lado izquierdo. La ACP en el segmento P1 presentó un calibre de 2,56 mm (DE 077) en el lado derecho y de 2,32 mm (DE 0,64) en el lado izquierdo. La longitud de estas arterias correspondió a 9,43 mm (DE 8,92) en el lado derecho y de 8,82 mm (DE 7,33 ) en el lado izquierdo. Las dimensiones observadas demuestran variabilidad que consideramos interesante de considerar en la anatomía quirúrgica.

The anatomical and clinical anatomy of the arterial circle of brain knowledge , is each time more necessary by cause of the complex neural relation of its components and great variability. Thirty six unfixed brain were obtained at autopsy from adult individuals without signs of cerebrovascular disease and the specimens had registered bioanthropological data. The caliber of the posterior communicating arteries corresponds to 1.08 mm (S.D. 0.45) mean both sides and the longitude to 17.51 mm (S.D. 7.9 ) in the right side and 16.9 mm (S.D. 8.0) in the left side. The P1 segment of the posterior cerebral artery presented a caliber of 2.56 mm (S.D. 0.77) in the right side and of 2.32 mm (S.D. 0.64) in the left side. The length of these arteries corresponded to 9.43 mm (S.D.8.92) in the right side and of 8.82 mm (S.D. 7.33) in the left side. The observed dimensions present variability that we considered interesting to chirurgical anatomy.