Endovascular Treatment and Microsurgical Clipping for the Management of Paraclinoid Intracranial Aneurysms: A Systematic Review and Meta-Analysis

OBJECTIVE

We aimed to compare the efficacy and safety of microsurgical clipping versus endovascular treatment (EVT) for paraclinoid aneurysms.

METHODS

A systematic search for studies including patients with paraclinoid aneurysms treated with a microsurgical or endovascular technique was conducted in 6 databases from inception to February 2022. Efficacy outcomes included complete angiographic occlusion at last follow-up, favorable functional outcome, and recurrence of the aneurysm. For safety, we assessed a composite of intraoperative and postoperative complications. Data were pooled using a random-effects model.

RESULTS

A total of 95 studies including 6711 patients, 3029 in the surgical group and 3682 in the EVT group were found. Pooled rates of complete occlusion were 94% (95% CI 91%-96%; I2 = 0%) in the surgical group and 69% (95% CI 63%-74%; I2 = 79%) in the EVT group, respectively. The favorable functional outcome rate was 86% (95% CI 76%-92%; I2 = 72%) with surgical treatment and 95% (95% CI 92%-97%; I2 = 61%) with EVT. The rate of aneurysm recurrence with surgical treatment was 1% (95% CI 0%-4%; I2 = 0%) and 12% (95% CI 9%-16%; I2 = 57%) with EVT. The composite safety outcome rate in the surgical group was 24% (95% CI 18%-30%; I2 = 90%) and 10% (95% CI 8%-13%; I2 = 71%) in the EVT group.

CONCLUSIONS

Our findings suggest that microsurgical clipping seems to have a higher efficacy than EVT in terms of angiographic occlusion and aneurysm recurrence; however, EVT seems to be safer in terms of intraoperative and postoperative complications. Considering the heterogeneity and low-level evidence of the data available, further prospective randomized studies are warranted to confirm our findings.

Management of an Uncommon Complication: Anterior Choroidal Artery Occlusion by Posterior Clinoid Process Detected Through Intraoperative Monitoring After Clipping of Paraclinoid Aneurysm: 2-Dimensional Operative Video

Despite technological advances in endovascular therapy, surgical clipping of paraclinoid aneurysms remains an indispensable treatment option and has an acceptable profile risk. Intraoperative monitoring of motor and somatosensory evoked potentials has proven to be an effective tool in predicting and preventing postoperative motor deficits during aneurysm clipping.1,2 We describe the case of a 61-yr-old Japanese woman with a history of hypertension and smoking. During follow-up for bilateral aneurysms of ophthalmic segment of the internal carotid artery (ICA), left-sided aneurysm growth was detected. A standard pterional approach with extradural clinoidectomy was used to approach the aneurysm. After clipping, a significant intraprocedural change in motor evoked potential (MEP) amplitude was observed despite native vessel patency was confirmed through micro-Doppler and indocyanine green video angiography.3-5 After extensive dissection of the sylvian fissure and exposure of the communicating segment of ICA, the anterior choroidal artery was found to be compressed and occluded by the posterior clinoid because of an inadvertent shift of the ICA after clip application and removal of brain retractors. Posterior clinoidectomy was performed intradurally with microrongeur and MEP amplitude returned readily to baseline values. Computed tomography (CT) angiogram demonstrated complete exclusion of the aneurysm, and magnetic resonance imaging (MRI) was negative for postoperative ischemic lesions on diffusion weighted images. The patient tolerated the procedure well and was discharged home on postoperative day 3 with modified Rankin Scale (mRS) 0. The patient signed the Institutional Consent Form to undergo the surgical procedure and to allow the use of her images and videos for any type of medical publications.

Unruptured Paraclinoid Carotid Aneurysms Occur More Frequently in Younger Ages

Purpose

We investigated the age distribution of cerebral saccular aneurysms in various locations to clarify the differences by location and discuss the mechanism of formation.

Materials and Methods

We retrospectively assessed clinical material obtained from 1,252 unruptured aneurysms treated with endovascular embolization between 2004 and 2019. Age, sex, laterality, and size were investigated by the location of aneurysms, classified as cavernous internal carotid artery (ICA), paraclinoid ICA, supraclinoid ICA, anterior communicating artery, anterior cerebral artery, middle cerebral artery, basilar artery complex, and posterior inferior cerebellar artery. Paraclinoid aneurysms were subclassified into 3 patterns according to their projecting direction: S-type, with superior protrusion; M-type, with medial protrusion; and P-type, with posteroinferior protrusion.

Results

There was no significant difference by location for sex, laterality, and size. The mean age of patients with paraclinoid aneurysms (56.5 years old) was significantly lower than that of other aneurysm patients (64.3 years old). Notably, 40% of the patients with M-type aneurysms were <50 years old. This percentage was significantly higher than that of aneurysms at other locations (P<0.05).

Conclusion

We found a young female predominance for patients with paraclinoid carotid aneurysms. This study may suggest that congenital factors contribute to paraclinoid aneurysm formation as well acquired factors, such as hemodynamic stress, atherosclerotic wall damage, and local inflammation.

Microsurgical Clipping Techniques and Outcomes for Paraclinoid Internal Carotid Artery Aneurysms

BACKGROUND

Microsurgical clipping of paraclinoid aneurysms presents unique technical challenges because of the anatomical complexity of the paraclinoid region.

OBJECTIVE

To analyze microsurgical clipping techniques, complications, and outcomes associated with paraclinoid aneurysms, with a focus on clip selection and clipping technique according to aneurysm location.

METHODS

From 1997 to 2016, 231 unruptured paraclinoid aneurysms from 216 patients were treated using microsurgical clipping. We retrospectively reviewed patient records to analyze clinical outcomes.

RESULTS

A total of 80 aneurysms (34.6%) were treated with simple clipping. Among them, fenestrated clips were used with superior hypophyseal artery (SHA) aneurysms, but curved clips were used with most other aneurysms. A total of 151 aneurysms (65.6%) were treated using multiple clips, including tandem clipping for ophthalmic artery (OphA) aneurysms, tandem angled-fenestrated clipping for SHA and ventral carotid aneurysms, stacked clipping for dorsal carotid aneurysms, and various techniques for clinoidal segment/carotid cave aneurysms. Postoperative angiography was performed in 214 aneurysms (92.6%), and complete obliteration was confirmed in 195 aneurysms (91.1%). Using the modified Rankin Scale (mRS), overall functional outcome was good (mRS 0-2) in 99.6% of patients, although 30 cases (13.0%) showed new postoperative visual deficits.

CONCLUSION

Surgical clipping of paraclinoid aneurysms is an excellent treatment modality with good clinical outcomes and acceptable complication rates, particularly in centers with large experience in the microsurgical management of cerebrovascular disorders. Appropriate clip selection and clipping techniques are required to perform complete and safe clipping.

Intra- and extradural anterior clinoidectomy: anatomy review and surgical technique step by step

PURPOSE

The complex relations of the paraclinoid area make the surgical management of the pathology of this region a challenge. The anterior clinoid process (ACP) is an anatomical landmark that hinders the visualization and manipulation of the surrounding neurovascular structures, hence in certain surgical interventions might be necessary to remove it. We reviewed the anatomical relationships that involve the paraclinoid area and detailed the step-by-step techniques of intra and extradural clinoidectomy in cadaveric specimens.

MATERIALS AND METHODS

A literature review was done describing the most relevant anatomic relationships regarding the anterior clinoid process. Extradural and intradural clinoidectomy techniques were performed in six dry bone heads and in ten previously injected cadaverous specimens with colored latex (Sanan et al. in Neurosurgery 45:1267-1274, 1999) and each step of the procedure was recorded using photographic material. Finally, an analysis of the anatomical exposure achieved in each of the techniques used was performed.

RESULTS

The main advantage of the intradural clinoidectomy technique is the direct visualization of the neurovascular structures adjacent to the ACP when drilling, at the same time, opening the Sylvian fissure will allow the direct visualization of the ACP variants. The main advantage offered by the extradural technique is that the dura protects adjacent eloquent structures while drilling. Among the disadvantages, it is noted that the same dura that would protect the underlying structures also prevents the direct visualization of these neurovascular structures adjacent to the ACP.

CONCLUSION

We reviewed the anatomy of the paraclinoid area and made a step-by-step description of the technique of the anterior clinoidectomy in its intra- and extradural variants in cadaveric preparations for a better understanding.

Progressive Orbitotomy and Graduated Expansion of the Supraorbital Keyhole: A Comparison with Alternative Minimally Invasive Approaches to the Paraclinoid Region

BACKGROUND

Various minimally invasive approaches, such as supraorbital (SO), minipterional (MPT), and translateral orbital (TLO), can access the paraclinoid region. Studies have described these approaches individually but have not directly compared all of them in the same anatomic specimen.

METHODS

Using virtual reality models generated from computed tomography studies of living subjects, we simulated TLO, MPT, and variations of SO approaches, without and with removal of the orbital rim and sphenoid wing. We measured the area of freedom (AOF), distance, and angle of attack to 4 paraclinoid targets: anterior clinoid process, optic foramen, lateral superior orbital fissure, and maxillary strut.

RESULTS

For superiorly positioned targets, such as anterior clinoid process and optic foramen, MPT provided a larger AOF compared with the supraorbital approach. However, with progressive drilling of the orbital roof and lesser wing of the sphenoid, the SO corridor AOF was equivalent to MPT at the anterior clinoid process and larger at the optic foramen (P = 0.003). To the lateral superior orbital fissure, TLO had the most limited AOF, and MPT had the greatest (P < 0.01 for all comparisons). For the maxillary strut, MPT, TLO, and SO with orbitotomy and sphenoidectomy all provided a similar AOF.

CONCLUSIONS

For surgical targets in the paraclinoid region, MPT provided a greater AOF and shorter distance compared with TLO and limited SO approaches. With progressive enlargement of the SO corridor, SO with orbitotomy and sphenoidectomy matched and occasionally superseded the AOF of MPT. However, the AOF to inferomedial targets such as the maxillary strut was similar among all approaches.

Surgical clipping of a non-ruptured ophthalmic aneurysm through an extradural micropterional keyhole approach

BACKGROUND

Clipping continues to be one of the treatment strategies for ophthalmic artery aneurysms not amenable for stenting or coiling, or when long-term treatment durability is a concern. However, crescent development of endovascular techniques demands minimal invasiveness in the transcranial approaches while ensuring satisfactory results.

METHODS

We describe an extradural micropterional keyhole approach (eMKA) to the paraclinoid region and highlight the key anatomical elements of this surgical approach.

CONCLUSION

The eMKA is a minimally invasive approach that provides access to the paraclinoid region using an extradural corridor. Therefore, it is suitable for clipping of ophthalmic artery aneurysms and other paraclinoid aneurysms.

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

BACKGROUND

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.

METHODS

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).

RESULTS

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 33 months, 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 three months 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).

CONCLUSIONS

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.

Comparison of Stent-Assisted Coil Embolization and the Pipeline Embolization Device for Endovascular Treatment of Ophthalmic Segment Aneurysms: A Multicenter Cohort Study

BACKGROUND

Stent-assisted coil embolization and flow diversion with the Pipeline embolization device (PED) are both effective endovascular treatment options for ophthalmic segment aneurysms (OSAs) of the internal carotid artery. Here we present a large comparative cohort study.

METHODS

A multicenter, retrospective cohort comparison study of consecutively treated OSAs was conducted at 2 academic institutions in the United States comparing stent-coiling (between 2007 and 2015) and PED (between 2011 and 2016).

RESULTS

A total of 62 of OSAs were treated with stent-coiling and 106 were treated with the PED. The stent-coiling-treated aneurysms were larger, although the maximum diameter was not significantly different between the 2 groups (P = 0.05). The median duration of follow-up was 22.5 months for the stent-coiling group and 8.7 months for the PED group (P = 0.0002). Complete occlusion at last follow-up was achieved in 75.9% of aneurysms in the stent-coiling group and in 81.1% of aneurysms in the PED group (P = 0.516). The retreatment rate was higher with stent-coiling, but the difference did not reach statistical significance (P = 0.062). A good functional outcome was achieved in 96.6% of patients in the stent-coiling group and in 94.7% of those in the PED group (P = 0.707). The rate of neurologic complications was 4.8% in the stent-coiling group and 9.4% in the PED group (P = 0.376).

CONCLUSION

Stent-coiling and the PED were equally effective for treating OSAs. There were no significant differences in terms of procedural complications, angiographic, functional, and visual outcomes. PED may be more favorable for multiple adjacent OSAs.

Clinical and radiogical outcomes of endovascular detachable coil embolization in paraclinoid aneurysms : a 10-year experience

OBJECTIVE

Direct surgical clipping of paraclinoid aneurysms poses technical challenges to even very experienced neurosurgeons, making endovascular treatment an alternative treatment modality in many centers. We have therefore retrospectively evaluated the safety and efficacy of endovascular detachable coil embolization of paraclinoid aneurysms.

METHODS

From June 1997 to June 2007, 65 patients underwent endovascular detachable coiling for 67 paraclinoid aneurysms (of which 9 were ruptured and 58 were unruptured) in our institute. Their medical records, radiological images and readings, and operation records were reviewed retrospectively.

RESULTS

After the initial embolization procedure, complete occlusion was achieved in 29 (43.3%) of the aneurysms treated by endovascular detachable coiling. Six aneurysms required retreatment, with two each requiring one, two, or three additional endovascular procedures. Fifty-five (82.1%) aneurysms were measured by three-dimensional time of flight (TOF) magnetic resonance images (MRI) or transfemoral cerebral angiography (TFCA) at a mean follow-up of 29.7 months (range from 4 to 94 months), with 39 aneurysms (70.9%) showing complete occlusion. Thromboembolic events (3.8%) were the most frequent complication. Rupture did not occur during or after any of the procedures. According to the Glasgow Outcome Scale (GOS), 98.4% of the patients treated by coil embolization had a score of 4 or 5.

CONCLUSION

Our results indicate that endovascular detachable coiling is a safe and effective treatment modality in paraclinoid aneurysms.