Paraclinoid Aneurysms Research Articles

The extradural minipterional approach for the treatment of paraclinoid aneurysms: a cadaver stepwise dissection and clinical case series

Minipterional (MPT) craniotomy has recently been added to the neurosurgical armamentarium as a less invasive alternative to the pterional craniotomy for the treatment of parasellar lesions. However, its clinical applicability in the treatment of certain complex aneurysms, such as those arising in the paraclinoid region, remains unclear. To illustrate the microsurgical anatomy of a modified extradural MPT approach, which combines a classic MPT craniotomy with an extradural anterior clinoidectomy, and to demonstrate its clinical applicability in the treatment of complex paraclinoid aneurysms. A stepwise extradural MPT approach is illustrated in a cadaver study. Clinical outcome data from a series of 19 patients with 20 paraclinoid aneurysms treated surgically using the extradural MPT approach between 2016 and 2018 were retrospectively collected. In 95% of the cases, complete aneurysm occlusion was achieved. No aneurysm recurrences were seen during follow-up with a median length of 21months. The outcome, according to the modified Rankin Scale, was 0 points in 12 patients (63%), 1 point in 6 patients (32%), and 2 points in 1 patient (5%). Four out of 6 patients (67%) with initial visual symptoms showed improvement following treatment, whereas in two (11%), vision became worse. The extradural MPT approach ensures a sufficiently large exposure of the paraclinoid region that is comparable with conventional approaches with the advantage of being minimally invasive. Our case series demonstrates the feasibility of this approach for the treatment of complex paraclinoid aneurysms.

Anatomical assessment of the endoscopic endonasal approach for the treatment of paraclinoid aneurysms.

Endoscopic endonasal approaches (EEAs) are increasingly being incorporated into the neurosurgeon's armamentarium for treatment of various pathologies, including paraclinoid aneurysms. However, few anatomical assessments have been performed on the use of EEA for this purpose. The aim of the present study was to provide a comprehensive anatomical assessment of the EEA for the treatment of paraclinoid aneurysms. Five cadaveric heads underwent an endonasal transplanum-transtuberculum approach to expose the paraclinoid area. The feasibility of obtaining proximal and distal internal carotid artery (ICA) control as well as the topographic location of the origin of the ophthalmic artery (OphA) relative to dural landmarks were assessed. Limitations of the EEA in exposing the supraclinoid ICA were also recorded to identify favorable paraclinoid ICA aneurysm projections for EEA. The extracavernous paraclival and clinoidal ICAs were favorable segments for establishing proximal control. Clipping the extracavernous ICA risked injury to the trigeminal and abducens nerves, whereas clipping the clinoidal segment put the oculomotor nerve at risk. The OphA origin was found within 4 mm of the medial opticocarotid point on a line connecting the midtubercular recess point to the medial vertex of the lateral opticocarotid recess. An average 7.2-mm length of the supraclinoid ICA could be safely clipped for distal control. Assessments showed that small superiorly or medially projecting aneurysms were favorable candidates for clipping via EEA. When used for paraclinoid aneurysms, the EEA carries certain risks to adjacent neurovascular structures during proximal control, dural opening, and distal control. While some authors have promoted this approach as feasible, this work demonstrates that it has significant limitations and may only be appropriate in highly selected cases that are not amenable to coiling or clipping. Further clinical experience with this approach helps to delineate its risks and benefits.

Overcoming Daunting Challenges of Clipping of Paraclinoid Carotid-Ophthalmic and Superior Hypophyseal Artery Aneurysms: 2-Dimensional Operative Video.

This surgical video emphasizes the nuances that needed to overcome daunting challenges of clipping of paraclinoid carotidophthalmic and superior hypophyseal artery (SHA) aneurysms. To avoid hazardous manipulations, scarifying the ipsilateral SHA under visual evoked potential (VEP) guidance can be done without risk of postoperative visual decline. This technique is associated with better visual outcome.1 A 66-yr-old woman presented with gradually enlarging right paraclinoid carotidophthalmic and SHA aneurysms. The relationship between those aneurysms and the critical neurovascular structures made us facing a daunting challenge to preserve the visual function. To preserve the patency of the ophthalmic artery (oph.A), endovascular intervention was abandoned and a direct clipping surgery was selected. Following VEP settings, exposure of the cervical internal carotid artery for proximal control and right frontotemporal craniotomy, a subfrontal approach was used. To get adequate accessibility and safe maneuverability, the anterior clinoidectomy and unroofing of the optic canal were completed, then, the falciform ligament and the distal dural ring were carefully opened. Under VEP guidance, the oph.A and SHAs were temporarily occluded. VEP had been stable under repeated occlusions. The carotidophthalmic aneurysm was clipped with preservation of the oph.A. Besides, 1 ipsilateral SHA was sacrificed to achieve complete clipping of the SHA aneurysm. Final indocyanine green videoangiography confirmed obliteration of the paraclinoid aneurysms and patency of the oph.A, the other SHA and the tiny arterioles around the optic nerve. The postoperative course was uneventful. There was no evidence of postoperative visual disturbances. The patient has consented to the submission of the case report to the journal.

Factors influencing blood flow resistance from a large internal carotid artery aneurysm revealed by a computational fluid dynamics model.

ABSTRACTHyperperfusion syndrome occurs after treatment of a large or giant cerebral aneurysm. Recently, flow-diverter stent placement has emerged as an effective treatment method for a large cerebral aneurysm, but postoperative ipsilateral delayed intraparenchymal hemorrhage occurs in a minority of cases. The mechanism underlying delayed intraparenchymal hemorrhage is not established, but one possibility is hyperperfusion syndrome. The incidence of delayed intraparenchymal hemorrhage appears to be higher for giant aneurysms; hence, we speculated that large/giant aneurysms may create flow resistance, and mitigation by flow-diverter stent deployment leads to hyperperfusion syndrome and delayed intraparenchymal hemorrhage. The purpose of this study was to identify aneurysm characteristics promoting flow resistance by the analysis of pressure loss in an internal carotid artery paraclinoid aneurysm model using computational fluid dynamics. A virtual U-shaped model of the internal carotid artery siphon portion was created with a spherical aneurysm of various angles, body diameters, and neck diameters. Visualization of streamlines, were calculated of pressure loss between proximal and distal sides of the aneurysm, and vorticity within the aneurysm were calculated. The pressure loss and vorticity demonstrated similar changes according to angle, peaking at 60°. In contrast, aneurysm diameter had little influence on pressure loss. Larger neck width, however, increases pressure loss. Our model predicts that aneurysm location and neck diameter can increase the flow resistance from a large internal carotid artery aneurysm. Patients with large aneurysm angles and neck diameters may be at increased risk of hyperperfusion syndrome and ensuing delayed intraparenchymal hemorrhage following flow-diverter stent treatment.

Limited Indications for Clipping Surgery of Paraclinoid Aneurysm Based on Long-Term Visual Morbidity

Clipping of paraclinoid aneurysm is still challenging because of poor visual morbidity. The extradural temporopolar approach was applied to clip paraclinoid aneurysms, with the expectation of reducing visual morbidity. Factors related to poor visual morbidity were evaluated, to assess the results for clipping of paraclinoid aneurysms. A series of 40 unruptured paraclinoid aneurysms in 38 patients were clipped via extradural temporopolar approach. Preoperative and postoperative states of visual cognitive function and radiological outcomes were investigated. Aneurysms were classified into dorsal type or non-dorsal type, and small (<9 mm) or not-small (≥9 mm), respectively, to identify factors correlated with visual morbidity. Complete clipping rate was 90.0% without any recurrence (mean: 5.2 years). Visual morbidity was unexpectedly high at 28.9%, including 2.7% of blindness immediately after the operation, and 23.7% and 2.7% at the final examination (mean: 3.6 years). Multivariate analysis showed aneurysm size was significantly correlated with worse visual outcome. Visual morbidity was 13.3% and 11.1% for dorsal and the non-dorsal small aneurysms, respectively, and all these cases showed visual field defect limited to the nasal quadrant without decreased visual acuity. In contrast, the non-dorsal not-small aneurysms showed significantly worse visual morbidity (60%) with decreased visual acuity. Clipping via extradural temporopolar approach can achieve durable treatment for small unruptured paraclinoid aneurysms with acceptable visual morbidity. Visual morbidity of the not-small non-dorsal type, however, was poor. The indications for clipping of paraclinoid aneurysm should be limited to small aneurysms, especially the dorsal type in young patients.

Acceso minipterional interfascial simple y combinado, con peeling de fosa media y clinoidectomia anterior extradural. Serie clínica

Introducción: En las últimas dos décadas al acceso pterional clásico descrito por Yasargil se le han realizado modificacionesimportantes en búsqueda de acceder a la base del cráneo, tales como el acceso transcigomático y orbitocigomático; más recientemente, accesos mínimamente invasivos, abordajes keyhole. Es así como se ha descrito el acceso minipterionalcon disección interfascial, el que ha sido combinado con técnicas de la base del cráneo, clinoidectomía anterior extradural,peeling de fosa media y petrosectomía anterior de Kawase, por el equipo de Neurocirugía Vascular y de la base del Cráneodel Instituto de Neurocirugía (INCA), a cargo del Dr. Jorge Mura, logrando resolver patologías complejas por un acceso keyhole. Este trabajo presenta una serie clínica, multicéntrica, realizada por un mismo neurocirujano, y que tiene como objetivo demostrar que el acceso minipterional simple y combinado es reproducible en otros centros, con buenos resultados clínicos. Materiales y Métodos: El autor presenta una serie clínica, de 56 pacientes, tratados en el hospital San Pablo de Coquimbo y Clínica Elqui de La Serena, entre abril de 2017 y agosto de 2018, con un seguimiento prospectivo de los resultados clínicos, los cuales fueron evaluados con la escala de Rankin modificado. Resultados: En un total de 56 casos, predominó el sexo femenino (71%), la edad media fue de 53 años y la patología aneurismática fue lo más frecuente con 45 casos, de estos el 60% fueron aneurismas rotos; el 7% correspondieron a tumores de la base del cráneo y el 12,5% a hidrocefalias no comunicantes resueltas por la apertura de la lámina terminalis. En 9 casos se combinó el acceso minipterional con clinoidectomía anterior extradural y en 3 casos se hizo un peeling de fosa media. El mayor tiempo quirúrgico estuvo asociado al acceso minipterional combinado, ya sea por patología tumoral o aneurismas paraclinoideos. Se obtuvo un resultado neurológico favorable (ERm &lt; 3) en el 87,5% de los pacientes. Conclusión y Discusión: actualmente la evidencia ha dejado de manifiesto que el acceso minipterional tiene ventajas sobre otros accesos keyhole, principalmente por la posibilidad de poder combinarlo con técnicas de base del cráneo, pudiendo resolver patologías que antes no era posible tratar por accesos mínimamente invasivos. El acceso pterional clásico, sin embargo, sigue teniendo indicación en casos seleccionados. Por otra parte, esta serie clínica confirma que el acceso minipterional simple y combinado, es reproducible y que, utilizándolo con un adecuado manejo microquirúrgico, logra buenos resultados en patologías complejas.

Risk factor analysis of ischemic stroke following flow diverter placement for paraclinoid aneurysms

Objective To evaluate risk factors for acute ischemic stroke following treatment of paraclinoid aneurysms using flow diverters. Methods Between September 2015 and July 2018, 205 consecutive patients with 229 paraclinoid aneurysms were treated with Pipeline embolization device (PED) at Department of Interventional Neuroradiology, Beijing Tiantan Hospital, Capital Medical University. The aneurysm size and parent artery size were measured. According to the length, proximal and distal diameter of the parent artery, appropriate size of PED was deployed with or without coiling. Various potential risk factors associated with acute ischemic stroke following PED treatment were documented. Univariate and multivariate logistic regression analyses were applied to identify risk factors. Results Among the 205 patients with 229 paraclinoid aneurysms, 110 aneurysms were treated by PED and 119 aneurysms received PED with coiling, all PED were delivered and implanted successfully. Eighteen (8.8%) patients with 20 aneurysms had acute ischemic stroke after PED deployment. Univariate analysis suggested that ADP inhibition, high MA-ADP value, clopidogrel non-response, application of complex intraoperative techniques, and long operation time were associated with the acute ischemic stroke following PED treatment (all P<0.05). Further multivariate logistic regression analysis showed the clopidogrel non-response (OR=6.161, 95% CI: 1.480-25.649, P=0.012), application of complex intraoperative techniques (OR=8.405, 95% CI: 1.437-49.146, P=0.018) and operation time (OR=1.011, 95% CI: 1.002-1.020, P=0.022) were independent factors for acute ischemic stroke following PED treatment. Conclusions Clopidogrel non-response, application of complex intraoperative techniques and long operation time may increase the risk of ischemic events. Key words: Intracranial aneurysm; Stroke; Factor analysis, statistical; Flow diverter; Paraclinoid

Lower limb weakness with gyrus rectus hematoma: an unusual presentation of paraclinoid aneurysm; a case report with review of literature

Lower limb weakness is usually a feature of ruptured anterior communicating (ACom) aneurysms due to spasm of the anterior cerebral arteries. Paraclinoid aneurysms, in addition to other cardinal features of subarachnoid haemorrhage (SAH), usually present with headache and visual field defects due to compression of the optic pathway. We report a case of left paraclinoid aneurysm presenting with right lower limb weakness and gyrus rectus hematoma without SAH. The aneurysm was long, passing beneath the optic nerve to emerge in the inter-optic cistern, leading to such atypical presentation. The aneurysm was clipped successfully after drilling the clinoid. As per our knowledge, such a clinical presentation of paraclinoid aneurysm has not been reported in the literature till date.

Aneurismas paraclinoideos: experiencia personal de 1 año en el Hospital Regional de Temuco

Se presenta la experiencia personal en el tratamiento de 5 pacientes con 7 aneurismas paraclinoideos tratados quirúrgicamente en el Hospital Regional Temuco durante junio de 2015 y julio de 2016 (13 meses). Todos los pacientes fueron previamente discutidos con neurorradiologo Intervencional local y considerados no favorables para terapia endovascular. En todos ellos se realizó una craneotomía mini pterional con clinoidectomía extradural y exposición de la arteria carótida interna cervical. Cuatro pacientes consultaron con hemorragia subaracnoidea y requirieron cirugía cerebral de urgencia. En 6 aneurismas se realizó clipaje y en 1 trapping. Cuatro pacientes no tuvieron deterioro neurológico y evolucionaron favorablemente mientras que 1 paciente falleció por hipoperfusión secundario al trapping de la carótida supraclinoidea. Se enfatiza el manejo interdisciplinario, el plan preoperatorio y el conocimiento de la neuroanatomía en el tratamiento de esta patología.

A case report of retrograde suction decompression of a large paraclinoid aneurysm

Surgical clipping of large Paraclinoidal IC (Internal carotid) aneurysm pose a great challenge as there are adhesions hindering exposure of aneurysm dome and parent artery . Obtaining adequate visualization of the aneurysm neck is very difficult in these aneurysms, also in the access of proximal control. There are many methods to obtain a proximal control in these aneurysms. Retrograde suction decompression provides adequate visualization of the aneurysm neck and its relation with the optic apparatus. Retrograde suction decompression can be done by many methods. The technique done via open catheterization of superior thyroid artery is readily accessible and provides adequate relaxation of the aneurysm dome enabling complete dissection of the aneurysm from the surrounding important neurovascular structures. In this report of a case of left Paraclinoidal ICA aneurysm which was clipped applying this method, we elaborate on the technique and discuss other methods available for proximal control in these difficult aneurysms.

Microsurgical Treatment of Paraclinoid Aneurysms by Extradural Anterior Clinoidectomy: The Fujita Experience.

Introduction:Paraclinoid aneurysms pose technical difficulty in their approach, mainly because of their close proximity to neurovascular structures, deeper location, and a smaller corridor. Extradural anterior clinoidectomy is a highly beneficial technique in such cases, making more space to deal with these aneurysms. We describe our method of performing extradural anterior clinoidectomy in such patients.Materials and Methods:A total of 33 cases of paraclinoid internal carotid artery aneurysms presenting to Fujita Health University Banbuntane Hospital, Japan, were included. Females comprised the majority with 32 cases; the mean age was 54.8 years (range: 35–74 years). The mean size of the paraclinoid aneurysm was 5.3 mm (range: 3–12 mm).Results:Nine paraclinoid aneurysms were found projecting dorsally, 7 laterally, and 17 medially (Kazuhiko Kyoshim et al's. classification). An immediate complete occlusion rate of 100% was present. Visual disturbance was found in 6.2% of our patients. One of our patients developed permanent loss of vision.Conclusion:Extradural anterior clinoidectomy enables a better exposure to paraclinoid aneurysms. Precise anatomical knowledge along with microsurgical tactics is required to prevent and manage potential complications to achieve good outcomes.

Sidewall Aneurysm Geometry as a Predictor of Rupture Risk Due to Associated Abnormal Hemodynamics.

Background: Hemodynamics play an important role in intracranial aneurysm (IA) initiation, growth, and rupture. Yet there remains no definitive quantitative analysis between abnormal hemodynamics and geometrical risk of IA development.Objective: The present study aims to investigate whether abnormal hemodynamics in IA sacs can be predicted by surrogate geometric markers.Methods: Computational fluid dynamics (CFD) simulations were performed on paraclinoid aneurysms derived from digital subtraction angiography (DSA) of 104 IAs in 104 patients. Four basic IA geometric parameters including maximum height, perpendicular height, maximum width, and neck diameter were measured. Abnormal hemodynamics were defined and quantified as the surface area exposed to low wall shear stress (WSS) and high oscillatory shear index (OSI) using objectively-defined thresholds. Relationships between abnormal hemodynamics and specific geometric parameters were analyzed via multiple linear regression.Results: Adjusting for age, sex, and other clinical characteristics, multiple linear regression revealed a significant relationship (p < 0.001) between abnormal hemodynamics and both maximum width (β ≈ 1.2) and neck diameter (β ≈ −0.4), but not maximum height or perpendicular height. These findings were shown to be independent of the choice of abnormal hemodynamic indicators and threshold levels.Conclusions: Maximum width and neck diameter of IA sacs are robust surrogates of exposure to abnormal hemodynamics. Risk of rupture may be increased with wider aneurysms with narrower necks for paraclinoid aneurysms.

Early and midterm results of treatment of giant internal carotid artery paraclinoid aneurysms with trapping and flow diverters.

Flow diverter devices (FDD) carry risks of postoperative complications when treating aneurysms with wide necks, stenosis, and severe tortuosity of the parent vessel. In this study, we evaluated early and midterm results for the treatment of giant paraclinoid aneurysms managed by trapping and endovascular deployment of FDD. Medical records were analyzed for patients with giant paraclinoid aneurysms treated between July 2008 and December 2017 at National Centre for Neurosurgery with either a flow diverter or by trapping the aneurysm with or without extracranial-intracranial (EC-IC) bypass surgery. We recorded age, sex, clinical presentation, treatment modality, morbidity, and mortality. Clinical outcomes were assessed using a modified Rankin scale (mRS). Among 29 consecutive patients, 13 were treated with FDD, and 16 patients were managed by trapping the aneurysm, where 7/16 cases had preliminary EC-IC bypass. Of 16 trapping patients, six were trapped endovascularly and ten were trapped surgically. During the follow-up period (mean 33months, range 6-96), total exclusion of the aneurysm from the circulation was observed 100% of aneurysms in the trapping group and 84.6% in the FDD group (P = 0.192). Early postoperative morbidity was observed in three (23%) cases in the FDD group, and four (25%) in trapping group (P = 0.525). The FDD group had one (7.7%) fatal complication due to stent occlusion and severe ischemic stroke after threemonths postoperatively, despite appropriate antiplatelet therapy. There were no mortalities in the trapping group (P = 0.149). The rate of mRS 0-2 did not differ significantly across groups at discharge (81.3% vs. 69.2%; P = 0.667), and all patients had mRS 0-2 at follow-up (P = 1.000). FDD deployment for giant paraclinoid aneurysms results in comparable angiographic and clinical outcomes to aneurysm trapping. Despite implementation of modern endovascular treatment methods, aneurysm trapping remains a valuable treatment option in carefully selected patients with giant paraclinoid aneurysms.

Using Falciform Ligament as Surgical Landmark for Diagnosis of Paraclinoid Aneurysms

Using Falciform Ligament as Surgical Landmark for Diagnosis of Paraclinoid Aneurysms

In Reply to “Using Falciform Ligament as Surgical Landmark for Diagnosis of Paraclinoid Aneurysms”

In Reply to “Using Falciform Ligament as Surgical Landmark for Diagnosis of Paraclinoid Aneurysms”

Microsurgical treatment of paraclinoid aneurysms through Dolenc approach

Objective To investigate the surgical skills and clinical efficacy of microsurgical treatment of paraclinoid aneurysms via Dolenc approach. Methods The clinical data of 35 patients with paraclinoid aneurysms operated via Dolenc approach at Department of Neurosurgery, Shiyan Taihe Hospital from September 2014 to May 2018 were analyzed retrospectively. The 35 patients had 38 paraclinoid aneurysms, among which 13 were ruptured aneurysms (Hunt-Hess grade Ⅰ-Ⅲ) and 22 were unruptured.All patients underwent operation via pterional approach and paraclinoid aneurysms were exposed via Dolenc approach. In this study, 24 aneurysms were clipped directly and 11 were clipped and shaped. The intraoperative indocyanine green (ICG) angiography was performed to confirm the efficacy. Results Satisfactory results were achieved in 35 cases. All aneurysms were completely clipped which were confirmed by CT angiography or digital Subtraction angiography examination. Two patients with giant aneurysms developed cerebral infarction and mild hemiplegia on the contralateral side after surgery, which were improved in 1 following rehabilitation treatment. Three patients developed oculomotor nerve palsy which was improved after 3 months. Three patients with ruptured aneurysms had hydrocephalus within 2 months after operation and recovered following ventriculo-peritoneal shunt. All patients were followed up for a period of 1-43 months, with an average of 19±8 months. The GOS (Glasgow outcome scale) grade was Ⅴ in 29 cases, Ⅳ in 5 and Ⅲ in 1 at discharge. Conclusions The removal of anterior clinoid process in extradural space and dissociating distal dural ring via Dolenc approach is favorable for early control of parent artery, may provide a better surgical field for exposing and clipping aneurysms, and thus improve the safety and efficacy of surgical treatment of paraclinoid aneurysms. Key words: Intracranial aneurysm; Microsurgery; Paraclinoid; Dolenc approach

再塞栓時のStent 留置に際し3D Printer が有用だった大型傍鞍部内頸動脈瘤の1 例

再塞栓時のStent 留置に際し3D Printer が有用だった大型傍鞍部内頸動脈瘤の1 例

Hemodynamic Characteristics Associated With Paraclinoid Aneurysm Recurrence in Patients After Embolization.

Objective: To investigate the hemodynamic features before and after embolization of paraclinoidal aneurysms using hemodynamic numerical simulation and the influence of embolization on recurrence after embolization.Methods: From January 2016 to December 2017, we enrolled a total of 113 paraclinoidal aneurysms treated with embolization. They were divided into recurrent group and stable group depending on follow-up results. An aneurysm model was generated based on 3D-DSA before and after embolization. The hemodynamic characteristics were analyzed between two groups using Computational fluid dynamic (CFD).Results: In the recurrent group, the peak systolic WSS, OSI and velocity around the aneurysm neck areas prior to embolization were 20.47 ± 3.04 Pa, 0.06 ± 0.02 and 0.07 ± 0.03 m/s, respectively. These values were 23.50 ± 4.11 Pa, 0.06 ± 0.01 and 0.11 ± 0.02 m/s, respectively in the stable group (P > 0.05). The WSS, OSI, velocity around the same areas in the recurrent group after embolization were 35.59 ± 8.75 Pa, 0.07 ± 0.02 and 0.12 ± 0.03 m/s, respectively (P < 0.01). In the stable group, the WSS, OSI and velocity were 13.08 ± 2.89 Pa, 0.04 ± 0.01 and 0.07 ± 0.02 m/s, respectively (P < 0.01). After embolization, the WSS, OSI and velocity around the aneurysm neck areas in the recurrent group were significantly higher than those in the stable group.Conclusions: High peak systolic WSS, OSI and velocity around aneurysm neck areas after embolization of paraclinoidal aneurysms may be important factors leading to recurrence.

Contralateral Approach to Paraclinoid Aneurysms: Angiographic Analysis and Surgical Results of 12 Patients.

To explore the usefulness of a unilateral approach for clipping multiple aneurysms including a contralateral paraclinoid aneurysm. Between January 2011 and May 2016, the unilateral approach was used to clip a contralateral paraclinoid aneurysm plus additional ipsilateral aneurysms. The records of these patients were analyzed retrospectively. A total of 27 bilateral aneurysms in 12 patients were clipped successfully via a unilateral pterional craniotomy. All patients showed a good recovery (Glasgow Outcome Scale score: 5). Postoperative digital subtraction angiography or computed tomography angiography did not show any residual aneurysm. Of the three patients with preoperative visual symptoms, two showed improvement. No visual function impairment was observed among the others. The contralateral approach remains a safe and reliable treatment option for selected paraclinoid aneurysms and allows to clip additional ipsilateral aneurysm(s). Feasibility depends on the type of paraclinoid aneurysm and other specific related features. It is an alternative approach for experienced neurosurgeons.

The 25th anniversary of the retrograde suction decompression technique (Dallas technique) for the surgical management of paraclinoid aneurysms: historical background, systematic review, and pooled analysis of the literature.

Paraclinoid internal carotid artery (ICA) aneurysms frequently require temporary occlusion to facilitate safe clipping. Brisk retrograde flow through the ophthalmic artery and cavernous ICA branches make simple trapping inadequate to soften the aneurysm. The retrograde suction decompression (RSD), or Dallas RSD, technique was described in 1990 in an attempt to overcome some of those treatment limitations. A frequent criticism of the RSD technique is an allegedly high risk of cervical ICA dissection. An endovascular modification was introduced in 1991 (endovascular RSD) but no studies have compared the 2 RSD variations. The authors performed a systematic review of MEDLINE/PubMed and Web of Science and identified all studies from 1990-2016 in which either Dallas RSD or endovascular RSD was used for treatment of paraclinoid aneurysms. A pooled analysis of the data was completed to identify important demographic and treatment-specific variables. The primary outcome measure was defined as successful aneurysm obliteration. Secondary outcome variables were divided into overall and RSD-specific morbidity and mortality rates. Twenty-six RSD studies met the inclusion criteria (525 patients, 78.9% female). The mean patient age was 53.5 years. Most aneurysms were unruptured (56.6%) and giant (49%). The most common presentations were subarachnoid hemorrhage (43.6%) and vision changes (25.3%). The aneurysm obliteration rate was 95%. The mean temporary occlusion time was 12.7 minutes. Transient or permanent morbidity was seen in 19.9% of the patients. The RSD-specific complication rate was low (1.3%). The overall mortality rate was 4.2%, with 2 deaths (0.4%) attributable to the RSD technique itself. Good or fair outcome were reported in 90.7% of the patients.Aneurysm obliteration rates were similar in the 2 subgroups (Dallas RSD 94.3%, endovascular RSD 96.3%, p = 0.33). Despite a higher frequency of complex (giant or ruptured) aneurysms, Dallas RSD was associated with lower RSD-related morbidity (0.6% vs 2.9%, p = 0.03), compared with the endovascular RSD subgroup. There was a trend toward higher mortality in the endovascular RSD subgroup (6.4% vs 3.1%, p = 0.08). The proportion of patients with poor neurological outcome at last follow-up was significantly higher in the endovascular RSD group (15.4% vs 7.2%, p < 0.01). The treatment of paraclinoid ICA aneurysms using the RSD technique is associated with high aneurysm obliteration rates, good long-term neurological outcome, and low RSD-related morbidity and mortality. Review of the RSD literature showed no evidence of a higher complication rate associated with the Dallas technique compared with similar endovascular methods. On a subgroup analysis of Dallas RSD and endovascular RSD, both groups achieved similar obliteration rates, but a lower RSD-related morbidity was seen in the Dallas technique subgroup. Twenty-five years after its initial publication, RSD remains a useful neurosurgical technique for the management of large and giant paraclinoid aneurysms.