Unruptured Paraclinoid Aneurysm Treatment Effects on Visual Function: Systematic Review and Meta-analysis

An overview of decision-making in cerebrovascular treatment strategies: Part I - unruptured aneurysms

Introduction

Unruptured intracranial aneurysm treatment has evolved over the last two centuries, starting from the introduction of aneurysm ligation and clipping, up until the inception of endovascular treatment and further advancements in both fields.

Research question

The wide variety of aneurysm presentations and possible treatment modalities, complicates the understanding of decision-making for the treatment of a given aneurysm. The goal of this article is to provide an overview of the best available evidence concerning unruptured intracranial aneurysm decision-making and identify insights and hiatuses, as well as providing a scaffold to surpass the subjectiveness of decision-making.

Materials and methods

A literature review was performed for the most impactful articles on decision-making in unruptured intracranial aneurysm treatment, to provide an overview on current practice.

Results

Two groups of decision-altering factors were identified; patient-related and aneurysm-related factors. A summary is presented of the general evidence, and the influence of age, aneurysmal mass-effect, as well as size, morphological aspects and specific anatomical locations on decision-making.

Discussion and conclusion

Decision-making for an unruptured intracranial aneurysm often comes down to combining these different patient- and aneurysm-related factors. In this paper, an evidence-based overview is provided into these different factors which alter management of unruptured saccular aneurysms.

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.

Visual Evoked Potential Can Predict Deterioration of Visual Function After Direct Clipping of Paraclinoid Aneurysm With Anterior Clinoidectomy

BACKGROUND

The role of visual evoked potential (VEP) in direct clipping of the paraclinoid internal carotid artery (ICA) aneurysm remains uncertain.

OBJECTIVE

To examine whether intraoperative neuromonitoring with VEP can predict deterioration of visual function after direct clipping of the paraclinoid ICA aneurysm with anterior clinoidectomy.

METHODS

Among consecutive 274 patients with unruptured cerebral aneurysm, we enrolled 25 patients with paraclinoid ICA aneurysm treated by direct clipping after anterior clinoidectomy with intraoperative neuromonitoring with VEP in this study. We evaluated the visual acuity loss (VAL) and visual field loss (VFL) before surgery, 1 month after surgery, and at the final follow-up.

RESULTS

The VAL at 1 month after surgery (VAL1M) and VAL at the final follow-up (Final VAL) were significantly related to the reduction rate of VEP amplitude at the end of surgery (RedEnd%), more than 76.5%, and the maximal reduction rate of VEP amplitude during surgery (MaxRed%), more than 66.7% to 70%. The VFL at 1 month after surgery (VFL1M) and the VFL at the final follow-up (Final VFL) were significantly related to MaxRed% more than 60.7%.

CONCLUSION

VAL1M, Final VAL, VFL1M, and Final VFL could be significantly predicted by the value of RedEnd% and MaxRed% in direct clipping of Al-Rodhan group Ia, Ib, and II paraclinoid ICA aneurysms with anterior clinoidectomy.

Direct Clipping of Paraclinoid Aneurysm in Conjunction with Extradural Anterior Clinoidectomy: Technical Nuance and Functional Outcome

Objective Because of their anatomical features, treatment for paraclinoid aneurysms has remained to be challenging. Thus, the aim of this report is to prove the validity of our surgical method for unruptured paraclinoid aneurysms, together with surgical videos.

Study Design Between August 2017 and November 2019, we were able to perform surgical clipping for 11 patients with unruptured paraclinoid aneurysm using a completely unified method. This study investigated the effect of surgery on multiple measures, including visual impairment, brain contusion, temporalis muscle atrophy, and multiple neurocognitive functions.

Results Of the 67 unruptured aneurysms treated at our hospital, 17 were identified to be paraclinoid aneurysm, and 11 of them were treated by direct clipping using anterior clinoidectomy. Three were ophthalmic artery aneurysms, three were superior hypophyseal artery aneurysms, and five were anterior carotid wall aneurysms without branch projection. Only one patient had asymptomatic mild enlargement of the Marriott blind spots postoperatively. No brain contusion and temporalis muscle atrophy were observed in any cases. Only the Trail Making test (TMT) showed a significant worsening in the acute postoperative period: mean pre- and postoperative TMT scores were 59.1 ± 29.1 and 72.7 ± 37.3 for Part A (p = 0.018) and 80.5 ± 35.5 and 93.8 ± 39.9 for Part B (p = 0.030), respectively. However, it improved in the chronic phase.

Conclusion We can conclude that our surgical method is safe and can be considered an acceptable treatment. Although surgical stress can cause temporary executive dysfunction shortly after surgery, this decline is temporary.

Clipping Ophthalmic Segment Artery Aneurysms Using a Modified Subdural Dolenc Approach: Classification and Experience Sharing

BACKGROUND

Ophthalmic segment artery aneurysms (OSAs) are difficult to clip; therefore, improvement of the surgical method is of great significance to the prevention of complications, and the classification of the aneurysms is essential to formulate a reasonable surgical plan.

OBJECTIVE

To explore the strategies and effects of surgery for OSAs using a modified subdural Dolenc approach.

METHODS

The clinical data of 38 patients (12 men and 26 women, aged 48-73 years) with OSA were analyzed retrospectively. A total of 44 aneurysms were identified, 40 of which were OSAs. The 40 aneurysms were divided into types Ia1 (n = 2), Ia2 (n = 2), Ib (n = 6), IIa (n = 4), IIb (n = 4), IIIa (n = 0), IIIb (n = 4), IIIc (n = 16), and IV (n = 2) based on preoperative images. Thirty-nine OSAs were operated successfully through pterional craniotomy combined with the modified subdural Dolenc approach, and 1 aneurysm was clipped through the contralateral approach. Clinical outcomes were evaluated using the Glasgow Outcome Scale (GOS).

RESULTS

Thirty-nine OSAs were clipped, and one was wrapped. Visual dysfunction, headache, and dizziness improved after the operation in 18 patients. One patient had new visual impairment, and there were no deaths. At discharge, the GOS score was 5 in 36 cases, 4 in 1 case, and 3 in 1 case. Thirty-seven patients had a GOS score of 5, and 1 patient had a score of 3 at 6 months after the operation.

CONCLUSION

The modified subdural Dolenc approach (Zheng approach) for clipping OSAs may be associated with less trauma and good postoperative outcomes.

Predictor of Visual Impairment Following Paraclinoid Aneurysm Surgery: Special Consideration of Surgical Microanatomy Related to Paraclinoid Structures

BACKGROUND

Microsurgical clipping with extradural anterior clinoidectomy (EDAC) for paraclinoid aneurysm is an established technique with good angiographic outcomes, although postoperative worsening of visual acuity remains a concern. Multiple reports show visual acuity deteriorating after clipping, yet the cause remains unclear.

OBJECTIVE

To analyze results of asymptomatic paraclinoid aneurysm surgeries treated with EDACs, specifically focusing on the microanatomy of paraclinoid structure dissection. This determined the causes of delayed visual impairment and microsurgical indications.

METHODS

Results of the treatment with EDAC of 94 patients with cerebral aneurysm and normal preoperative visual acuity but also full visual fields were retrospectively analyzed.

RESULTS

The mean aneurysm size was 6.2 (±3.3) mm. Clipping was performed in 87 cases and trapping in 7 cases. Complete angiographic occlusion was observed in 91 patients. In 26 cases, a postoperative visual deficit occurred. A total of 20 cases exhibited partial visual field deficits, including 5 who were asymptomatic. Visual deficits were only detectable by postoperative ophthalmologic testing. Six showed light perception impairment or blinding. Of the 15 patients with symptomatic partial visual field deficits, 5 showed improvement at follow-up. Visual deficits persisted in 22 patients at the last follow-up. Multivariate logistic regression analysis revealed that medial projecting aneurysm (adjusted odds ratio [OR]: 10.43) and the opening of the carotidoculomotor membrane (adjusted OR: 5.19) were significantly related to visual impairment.

CONCLUSION

Excess dissection of carotidoculomotor membranes causes postoperative delayed visual worsening. For treating small, asymptomatic paraclinoid aneurysms, carotidoculomotor membranes should not be opened, and microsurgical clipping should not be performed for preoperative asymptomatic medial projecting aneurysms.

Visual Outcomes after Surgery for Paraclinoid Aneurysms: A Fujita Experience

INTRODUCTION

The surgical strategies for clipping of paraclinoid aneurysms are diverse. These aneurysms are unique in their location, as they closely abut the anterior clinoid process (ACP) and the optic nerve. The ultimate goal of clipping encompasses the exposure of neck of the aneurysm which is seldom complete without the manipulation of optic nerve and the ACP. This manipulation may result in disturbances of vision postoperatively. We analyze our results of visual outcomes in the surgery for paraclinoid aneurysms in this retrospective study.

MATERIALS AND METHODS

All patients with paraclinoid aneurysms who underwent surgery from June 2014 to June 2019 were included in the study. Surgical procedure was uniform in all patients which included anterior clinoidectomy and clipping of aneurysms as per the Bantane protocol. Glasgow Outcome Scale as well as vision was assessed at discharge and at 1 month and 6 months.

RESULTS

There were 77 cases of paraclinoid aneurysms operated during the abovementioned period. All patients had no symptoms related to vision preoperatively. Visual deterioration was noted in two patients. All patients were discharged with a good outcome on the Glasgow Outcome Scale.

CONCLUSION

Paraclinoid aneurysm has a good outcome when treated with surgery. The visual deterioration following surgery can be minimized with extradural anterior clinoidectomy and careful handling of the vessels and nerve.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.