Aneurysms of the ophthalmic segment. A clinical and anatomical analysis

Optic pathway infarct after Onyx HD 500 aneurysm embolization: visual pathway ischemia from superior hypophyseal artery occlusion

We report a case of visual deterioration after Onyx HD 500 embolization of a left 7 mm superior hypophyseal artery (SHA) aneurysm. After the procedure, the patient experienced a right incongruous homonymous hemianopia, and MRI showed an infarct of the ipsilateral optic chiasm/tract but no evidence of aneurysm mass effect or embolic cortical infarcts. The optic pathway ischemia is believed to be secondary to Onyx penetration and occlusion of an SHA branch near the aneurysm neck. Caution is advised when using liquid embolic agents to treat SHA aneurysms as SHA occlusion may lead to visual deficits.

Could the types of paraclinoid aneurysm be used as a criterion in choosing endovascular treatment? Neuro-radiologists' view

BACKGROUND

The type of paraclinoid aneurysm has been used to decide management methods. Our aim was to assess the relation of the types of paraclinoid aneurysms and outcomes after endovascular treatment and the efficiency of present endovascular techniques.

METHODS

A retrospective analysis was performed on patients with saccular paraclinoid aneurysms that had more than 6 months of angiographic follow-up or recurrence within this period after endovascular treatment from January 2009 to December 2010. Paraclinoid aneurysms were classified into two types and then further into four subtypes by a modified classification method. A classification-based microcatheter shaping method was used in the procedure. The significant risk factors of angiographic results were determined through correlation analysis and logistic regression analysis by SPSS 17.0.

RESULTS

There were 64 aneurysms in 56 patients; 28 aneurysms belonged to Type I, while 36 were Type II. A total of 12 aneurysms were managed with coil embolization, and 52 with stent-assisted coiling technique. Our classification-based microcatheter shaping method was successful in all cases. Coil protrusion happened in two cases without severe complications. Recurrence were found in 13 (20.3 %) aneurysms followed up at 12.42 ± 3.78 (mean±SD) months after treatment. The correlation between aneurysm types and immediate angiographic result or follow-up angiographic results did not reach statistical significance. Aneurysm types were not the risk factor of recurrence.

CONCLUSIONS

The types of paraclinoid aneurysm had not been significant correlated with outcomes of endovascular treatment. Fundus size was the significant risk factor of recurrence after endovascular treatment. A classification-based microcatheter shaping method may be used in endovascular treatment paraclinoid aneurysms. The present endovascular techniques are safe and effective.

Endovascular methods for the treatment of intracranial cerebral aneurysms

This article briefly discusses the clinical features, natural history, and epidemiology of intracranial cerebral aneurysms, along with current diagnostic imaging techniques for their detection. The main focus is on the basic techniques used in endovascular coiling of ruptured and nonruptured saccular intracranial cerebral aneurysms. After a discussion of each technique, a short review of the results of each form of treatment is given, concentrating on reported large case series. Specific complications related to the endovascular treatment of saccular intracranial aneurysms are then discussed.

Anatomical configuration of the Sylvian fissure and its influence on outcome after pterional approach for microsurgical aneurysm clipping

Background:

The sylvian fissure (SF) is the anatomical pathway used in a pterional approach, which leads to most aneurysms. There are four different anatomical variants of the SF described. In the present retrospective study the four different categories of the SF were studied in order to evaluate any correlation of these variants to surgical outcome.

Methods:

Patients treated for intracranial aneurysms by a pterional transsylvian approach during 2003-2012 (N = 237) were included in the study. The SF category was determined by analysis of preoperative computed tomography (CT) scanning. Patients were grouped into unruptured intracranial aneurysms (UIA) and ruptured intracranial aneurysms with subarachnoid hemorrhage (SAH) according to the Hunt and Hess grades. Brain edema, vasospasms, ischemic lesion rate, and outcome were evaluated for possible correlation with SF anatomical variants.

Results:

Postsurgically brain edema formation correlated significantly with more complex anatomical variants of the SF in patients with UIAs and in patients with Hunt and Hess 1 and 2. Ischemia rate, vasospasms, or clinical outcome was not negatively affected though.

Conclusion:

The classification of the SF as proposed by Yasargil is more than a pure anatomical observation. In this retrospective study, we show that the anatomical variants of the SF can be associated to postoperative complications like formation of brain edema or ischemic lesions Preoperative knowledge of the SF anatomy and possibly consecutive adapted extend of the surgical approach can decrease procedure-related morbidity.

Toward an endovascular internal carotid artery classification system

SUMMARY

Does the world need another ICA classification scheme? We believe so. The purpose of proposed angiography-driven classification is to optimize description of the carotid artery from the endovascular perspective. A review of existing, predominantly surgically-driven classifications is performed, and a new scheme, based on the study of NYU aneurysm angiographic and cross-sectional databases is proposed. Seven segments - cervical, petrous, cavernous, paraophthlamic, posterior communicating, choroidal, and terminus - are named. This nomenclature recognizes intrinsic uncertainty in precise angiographic and cross-sectional localization of aneurysms adjacent to the dural rings, regarding all lesions distal to the cavernous segment as potentially intradural. Rather than subdividing various transitional, ophthalmic, and hypophyseal aneurysm subtypes, as necessitated by their varied surgical approaches and risks, the proposed classification emphasizes their common endovascular treatment features, while recognizing that many complex, trans-segmental, and fusiform aneurysms not readily classifiable into presently available, saccular aneurysm-driven schemes, are being increasingly addressed by endovascular means. We believe this classification may find utility in standardizing nomenclature for outcome tracking, treatment trials and physician communication.

Angiographic characteristics of ruptured paraclinoid aneurysms: risk factors for rupture

BACKGROUND

The diagnosis and treatment of unruptured paraclinoid aneurysms has been increasing with the recent advent of diagnostic tools and less invasive endovascular therapeutic options. Considering the low incidence of rupture, investigation of the characteristics of ruptured paraclinoid aneurysm is important to predict rupture risk of the paraclinoid aneurysms. The objective of this study is to evaluate probable factors for rupture by analyzing the characteristics of ruptured paraclinoid aneurysms.

METHODS

A total of 2,276 aneurysms (1,419 ruptured and 857 unruptured) were diagnosed and treated endovascularly or microsurgically between 2001 and 2011. Among them, 265 were paraclinoid aneurysms, of which 37 were ruptured. Removing 12 blister-like aneurysms, 25 ruptured and 228 unruptured saccular aneurysms were included and the medical records and radiological images were retrospectively analyzed.

RESULTS

Of 25 aneurysms, 16 (64.0%) were located in the superior direction. Five were inferior located lesions (20%) and four were medially located lesions (16.0%). Laterally located lesions were not found. The mean size of aneurysms was 9.4 ± 5.6 mm. Ten aneurysms (40.0%) were ≥ 10 mm in size. Thirteen aneurysms (52.0%) were lobulated. The superiorly located aneurysms were larger than the other aneurysms (10.3 ± 5.8 mm vs. 7.7 ± 4.9 mm) and more frequently lobulated (ten of 16 vs. three of nine). In a comparative analysis, the ruptured aneurysms were located more in the superior direction compared with unruptured aneurysms (64 vs. 23.2%, p < 0.0001). Large aneurysms (36.0 vs. 7.9%, p < 0.0001), longer fundus diameter (mean 9.4 ± 5.6 vs. 4.8 ± 3.3 mm, p = 0.001), dome-to-neck ratio (mean 1.8 ± 0.9 vs. 1.2 ± 0.5, p < 0.0001), and lobulated shape aneurysms were more likely to be ruptured aneurysms (13 of 25 ruptured aneurysms, 52.0%, p = 0.001).

CONCLUSIONS

Rupture risk of the paraclinoid aneurysm is very low. However, superiorly located paraclinoid aneurysms appear more likely to rupture than other locations. Angiographically, more conservative indication for the treatment of paraclinoid aneurysm should be recommended except for superior located lesions.

Endoscopic endonasal transplanum approach to the paraclinoid internal carotid artery

Objective To investigate the relevance of an endoscopic transnasal approach to the surgical treatment of paraophthalmic aneurysms. Setting Binasal endoscopic transplanum surgery was performed. Participants Seven cadaver heads were studied. Main Outcome Measures (1) Dimensions of the endonasal corridor, including the operative field depth, lateral limits, and the transplanum craniotomy. (2) The degree of vascular exposure. (3) Surgical maneuverability and access for clip placements. Results The mean operative depth was 90 ± 4 mm. The lateral corridors were limited proximally by the alar rim openings (29 ± 4 mm) and distally by the distance between the opticocarotid recesses (19 ± 2 mm). The mean posteroanterior distance and width of the transplanum craniotomy were 19 ± 2 mm and 17 ± 3 mm, respectively. Vascular exposure was achieved in 100% of cases for the clinoidal internal carotid artery (ICA), ophthalmic artery, superior hypophyseal artery, and the proximal ophthalmic ICA. Surgical access and clip placement was achieved in 97.6% of cases for vessels located anterior to the pituitary stalk (odds ratio [OR] 73.8; 95% confidence interval [CI] 7.66 to 710.8; p = 0.00). Conclusion The endoscopic transnasal approach provides excellent visualization of the paraclinoid region vasculature and offers potential surgical alternative for paraclinoid aneurysms.

Safety of drilling for clinoidectomy and optic canal unroofing in anterior skull base surgery

BACKGROUND

Skull base drilling is a necessary and important element of skull base surgery; however, drilling around vulnerable neurovascular structures has certain risks. We aimed to assess the frequency of complications related to drilling the anterior skull base in the area of the optic nerve (ON) and internal carotid artery (ICA), in a large series of patients.

METHODS

We included anterior skull base surgeries performed from 2000 to 2012 that demanded unroofing of the optic canal, with extra- or intradural clinoidectomy and/or drilling of the clinoidal process and lateral aspect of the tuberculum sella. Data was retrieved from a prospective database and supplementary retrospective file review. Our IRB waived the requirement for informed consent. The nature and location of pathology, clinical presentation, surgical techniques, surgical morbidity and mortality, pre- and postoperative vision, and neurological outcomes were reviewed.

RESULTS

There were 205 surgeries, including 22 procedures with bilateral optic canal unroofing (227 optic canals unroofed). There was no mortality, drilling-related vascular damage, or brain trauma. Complications possibly related to drilling included CSF leak (6 patients, 2.9 %), new ipsilateral blindness (3 patients, 1.5 %), visual deterioration (3 patients, 1.5 %), and transient oculomotor palsy (5 patients, 2.4 %). In all patients with new neuropathies, the optic and oculomotor nerves were manipulated during tumor removal; thus, new deficits could have resulted from drilling, or tumor dissection, or both.

CONCLUSION

Drilling of the clinoid process and tuberculum sella, and optic canal unroofing are important surgical techniques, which may be performed relatively safely by a skilled neurosurgeon.

Visual outcomes for surgical treatment of large and giant carotid ophthalmic segment aneurysms: a case series utilizing retrograde suction decompression (the “Dallas technique”)

Object

The authors report their results in a series of large or giant carotid ophthalmic segment aneurysms clipped using retrograde suction decompression.

Methods

A retrospective review of clinical data and treatment summaries was performed for 18 patients with large or giant carotid artery ophthalmic segment aneurysms managed operatively via retrograde suction decompression. Visual outcomes, Glasgow Outcome Scale (GOS) scores, and operative complications were determined. Postoperative angiography was assessed.

Results

During a 17-year period, 18 patients underwent surgery performed using retrograde suction decompression. The mean aneurysm size was 26 mm. Three patients presented with subarachnoid hemorrhage. Fourteen of 18 patients presented with visual symptoms. Eleven (79%) of these 14 patients experienced visual improvement and the remaining 3 (21%) experienced worsened vision after surgery. Of 3 patients without visual symptoms and a complete visual examination before and after surgery, 1 had visual worsening postoperatively. One aneurysm required trapping and bypass, and all others could be clipped. Postoperative angiography demonstrated complete occlusion in 9 of 17 clipped aneurysms and neck remnants in the other 8 clipped aneurysms. One (5.5%) of 18 patients experienced a stroke. Eighteen patients had a GOS score of 5 (good outcome), and 1 patient had a GOS score of 4 (moderately disabled). There were no deaths. There was no morbidity related to the second incision or decompression procedure. Prolonged improvement did occur, and even in some cases of visual worsening in 1 eye, the overall vision did improve enough to allow driving.

Conclusions

Retrograde suction decompression greatly facilitates surgical clipping for large and giant aneurysms of the ophthalmic segment. Visual preservation and improvement occur in the majority of these cases and is an important outcome measure. Developing endovascular technology must show equivalence or superiority to surgery for this specific outcome.

Microsurgical treatment of ophthalmic segment aneurysms

Ophthalmic segment aneurysms refer to superior hypophyseal artery aneurysms, true ophthalmic artery aneurysms, and their dorsal variant. Indications for treatment of these aneurysms include concerning morphological features, large size, visual loss, or rupture. Although narrow-necked aneurysms are ideal endovascular targets, more complex and larger lesions necessitating adjunctive stent or flow-diversion techniques may be suitably treated with long-lasting, effective clip ligation instead. This is particularly relevant in the consideration of ruptured ophthalmic segment aneurysms. This article provides a depiction of microsurgical treatment of ophthalmic segment aneurysms with an accompanying video demonstration. Emphasis is placed on microsurgical anatomy, the intradural anterior clinoidectomy and clipping technique. The intradural anterior clinoidectomy, demonstrated in detail in our Supplementary video, provides significant added exposure of the ophthalmic segment of the internal carotid artery, allowing for improved aneurysm visualization. In the management of superior hypophyseal artery aneurysms, emphasis is placed on identifying and preserving superior hypophyseal artery perforators, using serial fenestrated straight clips rather than a single right-angled fenestrated clip to obliterate the aneurysm. Post-clipping indocyanine green dye angiography is a crucial tool to confirm aneurysm obliteration and the preservation of the parent vasculature and adjacent superior hypophyseal artery perforators. With careful attention to the nuances of microsurgical clipping of ophthalmic segment aneurysms, rewarding results can be obtained.

Unruptured non-branching site aneurysms located on the anterior (dorsal) wall of the supraclinoid internal carotid artery: aneurysmal characteristics and outcomes following endovascular treatment

BACKGROUND

This study was undertaken to evaluate the aneurysmal characteristics and clinico-radiological outcomes of unruptured non-branching site aneurysms located on the anterior (dorsal) wall of the supraclinoid internal carotid artery (ICA).

METHODS

The data of 34 patients that underwent endovascular treatment for 36 unruptured ICA anterior wall aneurysms were reviewed. ICA anterior wall aneurysms were defined as aneurysms that projected superiorly from the anterior wall of the ICA ophthalmic (n = 35) or communicating (n = 1) segment on lateral angiograms, without any branch vessel relationship. In addition, aneurysmal characteristics and treatment outcomes were compared with those of 60 unruptured aneurysms originating from the posterior (ventral) wall of the ICA ophthalmic segment.

RESULTS

Patients with an ICA anterior wall aneurysm frequently had a mirror aneurysm on the contralateral side (14.7 % versus 3.3 %) or another ICA aneurysm (35.3 % versus 15 %). Two of the 36 ICA anterior wall aneurysms exhibited ICA narrowing suggestive of dissection, and another five had dysplastic ICA dilatation around the neck. Stent-assisted embolization was more frequently performed for ICA anterior wall aneurysms (66.7 % versus 36.7 %) because of unfavorable dome/neck (mean, 1.21) and aspect (mean, 1.15) ratios, and because of microcatheter instability associated with superior aneurysmal projections against the abrupt curvature of the carotid siphon. Procedure-related thromboembolic complications occurred in three patients in the anterior aneurysm group, but no patient deteriorated clinically. Immediate radiological outcomes were more unfavorable for ICA anterior wall aneurysms (residual sac, 36.1 % versus 16.7 %). Nevertheless, rates of recanalization (2.9 % versus 5.2 %) and progressive occlusion (24.7 % versus 8.1 %) during follow-up slightly favored ICA anterior wall aneurysms. Two stent-treated ICA anterior wall aneurysms developed asymptomatic ICA steno-occlusion (8.3 %).

CONCLUSIONS

Stent-assisted embolization is safe and effective for the treatment of unruptured ICA anterior wall aneurysms exhibiting unfavorable aneurysmal geometries and projections for coil embolization.

Visual sequelae after consensus-based treatment of ophthalmic artery segment aneurysms: the Johns Hopkins experience

BACKGROUND

To determine the anatomic and visual outcomes of patients with ophthalmic artery segment aneurysms treated at The Johns Hopkins Hospital using a consensus-based treatment algorithm.

METHODS

Retrospective record review of a prospectively accrued case series of 88 patients (101 aneurysms) treated between January 2004 and July 2009. Presenting symptoms and aneurysm parameters were recorded for all subjects. Treatment strategy for all patients was determined by consensus among neurosurgeons, neurointerventionalists, neurologists, and neuroophthalmologists meeting to review the clinical cases on a weekly basis. Final clinical outcomes (aneurysm control, functional status, and vision) were ascertained from in-house examinations, medical records, telephone interviews, or a combination of these methods. Risk factors for visual or other complications were evaluated.

RESULTS

An optic neuropathy was present in at least 30 (34%) of 88 patients after treatment. Presumed new visual loss occurred in 24 (27%) of these patients. The remaining 6 patients had preexisting optic neuropathy-related visual loss that worsened after treatment. No patient with a preexisting optic neuropathy improved following treatment.

CONCLUSION

Ophthalmic artery segment aneurysms present a treatment challenge because of their anatomic complexity and relationship to critical neural structures, particularly the visual sensory pathway. We have adopted a consensus-based treatment approach in an effort to optimize patient outcomes and aneurysm control. Although our approach resulted in durable treatment of the aneurysm, a sizable proportion of patients experienced new vision loss after treatment, and no patient with preexisting visual loss related to their aneurysm experienced visual improvement after treatment. We recommend that all patients with ophthalmic artery aneurysms receive careful and thorough preprocedural counseling to ensure they are aware of the risks and benefits of treatment regardless of the method used.

Meningeal layers around anterior clinoid process as a delicate area in extradural anterior clinoidectomy : anatomical and clinical study

Objective

Removal of the anterior clinoid process (ACP) is an essential process in the surgery of giant or complex aneurysms located near the proximal internal carotid artery or the distal basilar artery. An extradural clinoidectomy must be performed within the limits of the meningeal layers surrounding the ACP to prevent morbid complications. To identify the safest method of extradural exposure of the ACP, anatomical studies were done on cadaver heads.

Methods

Anatomical dissections for extradural exposure of the ACP were performed on both sides of seven cadavers. Before dividing the frontotemporal dural fold (FTDF), we measured its length from the superomedial apex attached to the periorbita to the posterolateral apex which connects to the anterosuperior end of the cavernous sinus.

Results

The average length of the FTDF on cadaver dissections was 7 mm on the right side and 7.14 mm on the left side. Cranial nerves were usually exposed when cutting FTDF more than 7 mm of the FTDF.

Conclusion

The most delicate area in an extradural anterior clinoidectomy is the junction of the FTDF and the anterior triangular apex of the cavernous sinus. The FTDF must be cut from the anterior side of the triangle at the periorbital side rather than from the dural side. The length of the FTDF incision must not exceed 7 mm to avoid cranial nerve injury.

Intradural endoscope-assisted anterior clinoidectomy: a cadaveric study

OBJECTIVE

The anterior clinoid process (ACP) is critically related to the clinoidal portion of the internal carotid artery (ICA). The deep location of the ACP makes treatment of vascular and neoplastic lesions related to the ACP challenging. Removal of the ACP is advocated to facilitate treatment of such lesions. However injury to the clinoidal ICA remains a potential and dreadful complication of ACP removal. The aim of this study was to demonstrate an endoscopic assisted technique to perform intradural removal of the ACP via a pterional approach with continuous visualization of the clinoidal ICA.

METHODS

Sixteen bilateral pterional dissections were performed in 8 glutaraldehyde embalmed, colored silicone injected, adult cadaveric heads. Using a standard pterional approach, we performed drilling of the ACP in 2 stages. Stage 1 consisted of extradural microscopic removal of the sphenoid ridge so as to gain access to the origin of the ACP. Stage 2, the endoscopic stage, consisted of intradural endoscopic removal of the ACP and mobilization of the clinoidal segment of the ICA. We used 2.7 mm, 0° and 30° angled endoscopes.

RESULTS

In all the specimens we were able to remove the ACP while at the same time continuously visualizing the clinoidal ICA. The exposure of the clinoidal ICA and of adjoining neuro-vascular structures including the intracranial optic nerve was excellent and was accomplished with minimal frontal lobe retraction. Mobilization of the clinoidal ICA led to unhindered exposure of the parasellar region.

CONCLUSIONS

Endoscopic assisted ACP removal with continuous ICA visualization was feasible in our model. Continuous visualization of the clinoidal ICA should theoretically decrease the risk of inadvertent ICA injuries. Clinical studies to validate this laboratory study are necessary.

Open and endovascular treatment of unruptured carotid-ophthalmic aneurysms: clinical and radiographic outcomes

BACKGROUND

Aneurysms of the carotid-ophthalmic artery present unique challenges to cerebrovascular neurosurgeons given their proximity to vital anatomic structures.

OBJECTIVE

To report our experience with a combined-modality treatment of unruptured carotid-ophthalmic aneurysms over a 12-year period.

METHODS

A retrospective review of 161 patients who underwent open, endovascular, or combined treatment of 170 aneurysms from January 1997 to July 2009 was conducted. Medical records, operative reports, office notes, and follow-up angiograms were reviewed to obtain data on patient demographics, angiographic results, and clinical outcomes.

RESULTS

One hundred forty-seven aneurysms were treated via endovascular techniques; 17 aneurysms (10%) were treated with microsurgical clip ligation; and 6 aneurysms (3.5%) were treated with a combined approach. Of the aneurysms treated via an endovascular approach alone, 81.6% of aneurysms had evidence of ≥ 95% occlusion on initial angiogram. There was a 1.4% rate of major complications associated with the initial procedure. Twenty-six of these aneurysms (18.9%) required further intervention on the basis of early angiographic results. Major complications occurred after 6 of 23 open microsurgical procedures (26.1%), including 2 instances of permanent visual loss. Nine clipped patients had long-term angiographic follow-up; none required further intervention.

CONCLUSION

Endovascular treatment of carotid-ophthalmic aneurysms with modern endovascular techniques can be performed safely and efficaciously in the elective setting.

Superior hypophyseal artery aneurysms have the lowest recurrence rate with endovascular therapy

BACKGROUND AND PURPOSE

Given the challenges posed by surgical clipping, endovascular techniques have been increasingly used to treat SHA aneurysms. The purpose of this study was to assess the safety and efficacy of endovascular techniques in the treatment of SHA aneurysms.

MATERIALS AND METHODS

Medical charts and initial and follow-up angiograms were reviewed retrospectively for all patients treated with endovascular procedures at our institution between January 2006 and February 2011.

RESULTS

We identified 87 patients with SHA aneurysms who were treated with endovascular techniques. Of these patients, 79 were women and only 8 were men (90.8% female predominance). Thirty-five patients were treated with coil embolization; 45, with stent-assisted coiling; 4, with balloon-assisted coil embolization; and 3, with a flow-diversion technique. Minor complications occurred in 2 patients (2.2%). None of the patients had a major complication. The mortality and permanent morbidity rates related to the procedure were 0%. Imaging follow-up was available for 89.4% of patients (DSA in 65, MRA in 11 patients) at a mean time point of 10.4 months (range, 6-60 months). Of the 76 patients with available follow-up, 3 patients had a recurrence (3.9%) and only 1 required further intervention (1.3%). Stent-assisted coiling was associated with lower recurrence rates than simple coil embolization.

CONCLUSIONS

SHA aneurysms have the lowest recurrence rate with endovascular treatment compared with aneurysms in other locations by using historical data. Because of its safety and efficacy, endovascular therapy should be considered the procedure of choice for the treatment of SHA aneurysms.

Long-term visual outcome and aneurysm obliteration rate for very large and giant ophthalmic segment aneurysms: assessment of surgical treatment

BACKGROUND

Standard endovascular therapy has shown little success in treatment of very large and giant ophthalmic segment aneurysms. We hypothesize that surgical treatment of these aneurysms yields better results in terms of visual function and aneurysm obliteration.

METHODS

The Toronto Brain Vascular Malformation Study Group database was analyzed to retrieve patients treated surgically for very large (>15 mm) and giant aneurysms of the ophthalmic segment of the carotid artery. Preoperative data and postoperative long-term outcomes with specific consideration for visual function and aneurysm obliteration were evaluated.

RESULTS

Of the 257 patients with ophthalmic and paraophthalmic aneurysms, 38 patients had very large or giant aneurysms. Twenty-one underwent surgical treatment; 19 had direct clipping; 1 had trapping, and 1 underwent trapping and bypass. Fifteen patients had unruptured and six had ruptured aneurysms. The mean follow-up period was 88 months. Six (28%) aneurysms had a small residual neck remnant. Of the 12 patients with documented preoperative visual deficit, 9 (75%) improved, 2 (16%) remained stable, and 1 (8%) worsened. Two patients had mild to moderate new visual deficit. Thus, the surgery-related visual complications were 14%. Eighteen patients (86%) had a good or excellent outcome (GOS IV and V). Presentation with prior visual deficit and poor neurological function were predictors of worse visual and clinical outcome, respectively (P = 0.02 and 0.01).

CONCLUSIONS

There is considerable surgery-related risk for optic pathways during treatment of very large and giant ophthalmic segment aneurysms. Surgery, however, seems to be the treatment of choice in terms of overall visual outcome and aneurysm obliteration as compared to the current endovascular results in this subset of patients.

Cerebral aneurysms with intrasellar extension: a systematic review of clinical, anatomical, and treatment characteristics

Object

Intrasellar aneurysms are rare lesions that often mimic pituitary tumors, potentially resulting in catastrophic outcomes if they are not appropriately recognized. The authors aimed to characterize the clinical and anatomical details of this poorly defined entity in the modern era of neuroimaging and open/endovascular neurosurgery.

Methods

A PubMed literature review was conducted to identify all studies reporting noniatrogenic aneurysms with intrasellar extension, as confirmed by CT or MR imaging and angiography. Clinical, anatomical, and treatment characteristics were analyzed.

Results

Thirty-one studies reporting 40 cases of intrasellar aneurysms were identified. Six patients (15%) presented with aneurysmal rupture. Patients with unruptured aneurysms presented with the following signs and symptoms: headache (61%), visual field cuts/decreased visual acuity (61%), endocrinopathy (57%), symptomatic hyponatremia (21%), and cranial nerve paresis (other than optic nerve) (18%). The most common endocrine abnormalities were hyperprolactinemia and hypogonadism. Eight aneurysms (20%) were diagnosed in conjunction with a pituitary adenoma. Aneurysms could be categorized into 2 primary anatomical groups as follows: 1) cavernous/clinoid segment internal carotid artery (ICA) (infradiaphragmatic) aneurysms with medial extension into the sella; and 2) suprasellar (supradiaphragmatic) aneurysms originating from the ophthalmic segment of the ICA or from the anterior communicating artery, with inferomedial extension into the sella. The mean diameters of infradiaphragmatic and supradiaphragmatic aneurysms were 14.5 and 21.8 mm, respectively. Infradiaphragmatic aneurysms were much more likely to present with endocrinopathy, whereas supradiaphragmatic ones presented more commonly with visual disturbances. Aneurysms with infradiaphragmatic growth were generally treated using either endovascular techniques or surgical trapping and bypass, while supradiaphragmatic aneurysms were more often treated by surgical clipping.

Conclusions

Aneurysms with intrasellar extension typically present due to mass effect on surrounding structures, and they can be classified as infradiaphragmatic cavernous or clinoid segment ICA aneurysms, or supradiaphragmatic ophthalmic ICA or anterior communicating artery aneurysms. Varying approaches exist for treating these complex aneurysms, and intervention strategies depend substantially on the anatomical subtype.

Complications of anterior clinoidectomy through lateral supraorbital approach

OBJECTIVE

We reviewed the surgical complications from our recent experience in vascular and tumor patients who underwent anterior clinoidectomy through the lateral supraorbital (LSO) approach.

METHODS

Between June 2007 and January 2011, a total of 82 patients with neoplastic and vascular lesions underwent anterior clinoidectomy by the senior author (J.H.) through the LSO approach. We analyzed the operative videos paying particular attention to the surgical technique used for removal of the anterior clinoid process (ACP) and compared the microsurgical nuances to postoperative complications related to anterior clinoidectomy.

RESULTS

Forty-five patients were treated for aneurysms; 35 patients for intraorbital, parasellar, and suprasellar tumors; and 2 patients for carotid-cavernous fistulas. Intradural anterior clinoidectomy was performed in 67 (82%) cases; in 15 (18%) cases an extradural approach was used. In 51 (62%) cases, ACP was removed completely, whereas in the remaining 31 (38%) a tailored anterior clinoidectomy was performed. Four (5%) patients had new postoperative visual deficits and 3 (4%) experienced a worsening of preoperative visual deficits. Twelve (15%) patients improved their preoperative visual deficits after intradural anterior clinoidectomy. Ultrasonic bone device is a useful tool but may damage the optic nerve when performing anterior clinoidectomy. There was no mortality in our series.

CONCLUSION

Anterior clinoidectomy can be performed through an LSO approach with a safety profile that is comparable to other approaches. Ultrasonic bone dissector is a useful tool but may lead to injury of the optic nerve and should be used very carefully in its vicinity.

Influence of surgical or endovascular treatment on visual symptoms caused by intracranial aneurysms: single-center series and systematic review

Object

Intracranial aneurysms of the anterior circulation might become symptomatic by causing visual deficits. The influence of treatment modality on improvement is still unclear. The objective of this study was to analyze the recovery of visual deficits caused by the mass effect of intracranial aneurysms after surgical clipping or endovascular treatment.

Methods

Between June 1999 and December 2009, 20 patients with unruptured intracranial aneurysms causing visual dysfunction due to compression of the optical nerve were treated at the authors' institution. Visual deficits were recorded at admission and at follow-up. To evaluate a larger number of patients, MEDLINE was searched for published studies involving visual disturbance caused by an aneurysm. A multivariate analysis was performed to find independent predictors for favorable visual outcome.

Results

Nine (75%) of 12 patients treated surgically achieved improvement of visual symptoms, compared with 3 (38%) of 8 patients treated endovascularly. A literature review, including the current series, revealed a total of 165 patients with UIAs causing visual dysfunction. Surgical treatment was associated with a significantly higher rate of visual improvement (p = 0.002) compared with endovascular treatment. According to the multivariate analysis, surgical clipping was the only variable significantly associated with improvement of visual outcome (p = 0.02).

Conclusions

Aneurysm-related visual dysfunction developed from direct mechanical compression may improve after surgical clipping and endovascular coiling. However, based on the present series combined with pooled analysis of data from the literature, the only factor significantly associated with improvement of visual dysfunction was surgical clipping.

Combined microneurosurgical and endovascular "trapping-evacuation" technique for clipping proximal paraclinoidal aneurysms

A method is described in which a combined endovascular and microneurosurgical approach is used for clipping aneurysms of the proximal paraclinoidal segment of the internal carotid artery. By temporary occlusion of the cervical carotid artery and continuously retrograde sucking of blood from the distal vessel via a double lumen ballon catheter, clip application to large and critically located aneurysms is facilitated applying decompression to the trapped arterial segment under intraoperative somatosensory-evoked potential (SEP) monitoring.

Computer-generated microsurgical anatomy of the paraclinoid area

To represent multiple microstructures, including perforators, dura, and cranial nerves, and to allow understanding of the three-dimensional relations of the paraclinoid area, we made a computer graphics model. The source of the input data is a variety of publications showing the detailed anatomy of the paraclinoid area. To produce the model, we traced such data, input selected points for each structure, smoothed the lines with a spline program, and added depth using wire-framing and color alterations. The computer graphic model of the paraclinoid area showing perforators, dural ring, optic nerve, and so forth, was made using a paint method for hidden line removal. It can be rotated and viewed from any direction and thus allows understanding of the relations of the area. Using our method, it may be possible to obtain a more detailed model of various anatomies including the skull base, and such data would be useful for preoperative simulation to understand relative regional relations for a specific case and as a new navigational system for open microneurosurgery. Concepts and technical details of the method are described.

[Paraclinoid region: descriptive anatomy and radiological correlations with MR imaging]

OBJECTIVE

The paraclinoid region has a complex anatomy. The purpose of this study was to depict in details its anatomical landmarks and their radiological translations with magnetic resonance imaging (MRI).

MATERIAL AND METHOD

Ten anatomical specimens (20 paraclinoid regions) were prepared, then dissected and further analyzed with MRI in order to describe their important radio-anatomical structures (dural folds, osseous surfaces, arteries and nerves) along with their course and measurements, and the reference points of the carotid distal dural ring. The paraclinoid MR protocol consisted in a T2 high-resolution sequence with thin and contiguous slices acquired in a coronal (diaphragmatic) and sagittal oblique (carotid) plane. Reproducibility in living subjects was evaluated on 15 patients (30 paraclinoid regions). Statistical comparison was made between laboratory and MR measurements obtained on cadavers.

RESULTS

A detailed description of paraclinoid anatomy and structures was provided. Its landmarks were satisfactorily identified with the dedicated MR protocol. Reproducibility in living subjects was obtained. No statistical difference was found between laboratory and MR measurements.

CONCLUSION

This study provides a precise description of paraclinoid anatomical structures and their radiological correlations. This paraclinoid MR protocol allows locating paraclinoid lesions in comparison with the cavernous sinus roof, which is of paramount importance for the management of paraclinoid carotid artery aneurysms.

Microneurosurgical Management of Ophthalmic Segment of the Internal Carotid Artery Aneurysms

BACKGROUND:

Surgical clipping of ophthalmic segment aneurysms is more technically challenging than other anterior circulation aneurysms.

OBJECTIVE:

To analyze whether surgical clipping is an effective treatment for ophthalmic segment aneurysms with good clinical outcomes and acceptable complication rates.

METHODS:

From 1994 to 2009, a total of 86 aneurysms of the ophthalmic segment of the internal carotid artery were surgically clipped in 80 patients. We retrospectively reviewed the records of these patients to analyze the clinical outcome.

RESULTS:

Of the 86 aneurysms, 68 (79%) were large or giant. Cranial base modification was required in 28 operations. Drilling of the anterior clinoid process was performed in 49 operations. The mean follow-up was 27.38 months. Of the 80 patients, 76 were assessable for clinical outcome. At the last follow-up, 5 patients had a Glasgow Outcome Scale (GOS) score of 1, 4 had a GOS score of 3, 10 had a GOS score of 4, and 57 had a GOS score of 5. Thus, the clinical outcome was good (GOS scores of 5 and 4) in the majority (88%) of patients. Of the 15 patients who presented with visual problems before surgery, 77% showed improvement after surgical clipping. The overall visual morbidity rate was 2.5%. Outcome assessment indicated that infarcts (P = .000), hydrocephalus (P = .001), and poor grade (P = .000) were significant negative predictors of outcome.

CONCLUSION:

Surgical clipping is an effective treatment for ophthalmic segment of the internal carotid artery aneurysms with excellent or good clinical outcome. Infarcts, hydrocephalus, and poor grade were significant negative predictors of outcome. Surgical clipping may facilitate improvement in vision by decompression of the visual apparatus.

Peripheral ophthalmic artery aneurysm

Generally speaking, the term "ophthalmic aneurysms" refers to carotid-ophthalmic aneurysms, which arise from the internal carotid artery (ICA) wall at or around the origin of the ophthalmic artery (OA). In contrast, aneurysms arising from the OA stem or its branches, separate from the ICA are called peripheral OA aneurysms (POAAs). POAAs are a rare entity, which clinical features and natural course are not fully understood. A comprehensive literature review of reported aneurysms involving each segment of the OA was undertaken. The demographics, aetiology, clinical manifestations and treatment of reported POAAs are discussed. Of 35 retrieved cases, ten involved the intracranial segment, two were fusiform aneurysms in the optic canal, 17 arose from the intraorbital segment, and 6 involved either the lacrimal or the anterior ethmoidal branches. In 34 cases, clinical details were available; 18 patients experienced moderate to severe visual impairment including blindness, while seven patients had improvement in visual acuity as a result of surgical treatment. The present clinical review reveals that aneurysms of the OA stem and lacrimal branch are potentially threatening to visual acuity, while intracranial segment and anterior ethmoidal aneurysms can rupture and cause subarachnoid or intraparenchymal haemorrhage. Surgical intervention is mandatory in symptomatic cases to prevent visual deterioration or treat aneurismal rupture; alternatively, for small incidental POAAs "watchful waiting" may be indicated.

Intradural Clinoidectomy and Postoperative Headache in Patients Undergoing Aneurysm Surgery

BACKGROUND:

The incidence of severe, chronic postoperative headache in patients undergoing elective surgery for unruptured aneurysms is unknown. In addition, no clear risk factors have been identified for the development of postoperative headache.

OBJECTIVE:

To evaluate intradural drilling of the anterior clinoid process as a mechanism for the development of postoperative headache after open aneurysm repair.

METHODS:

A retrospective review of 128 patients undergoing open surgical treatment for unruptured, proximal carotid aneurysms treated at the University of Texas Southwestern Medical Center between January 2004 and December 2007. Patients who required intradural drilling of the anterior clinoid process were compared with patients in whom additional drilling was not necessary. The presence of postoperative headache and the duration and severity were noted.

RESULTS:

In 28% of patients who underwent surgery with intradural clinoidectomy severe headache developed vs 7% of patients without clinoidectomy. This result was statistically significant (P &lt; .05, Fisher exact test).

CONCLUSION:

Intradural drilling of the anterior clinoid process was associated with an increased incidence of postoperative headache compared with no resection. This implicates either the dural manipulation necessary to expose the clinoid and optic strut or the introduction of bone dust into the subarachnoid space as potential risk factors for postoperative headache.

Transarterial embolization of traumatic carotid-superior hypophyseal arterial cavernous fistula. A case report

A 26-year-old man presented with symptoms of progressive bilateral exophthalmos and swelling of the eyelids after a severe head injury. Angiography confirmed a direct carotid-superior hypophyseal arterial (SHA) cavernous fistula with petrosal sinus and intracavernous sinus drainage. Successful transarterial coil embolization of the fistula was performed with resolution of the patient's symptoms. To our knowledge, post-traumatic arteriovenous fistula between SHA and the cavernous sinus has not been previously reported. We hereby demonstrate an effective, minimally invasive method of occluding a rare fistula by transarterial embolization.

Distinction between Intradural and Extradural Aneurysms Involving the Paraclinoid Internal Carotid Artery with T2-Weighted Three-Dimensional Fast Spin-Echo Magnetic Resonance Imaging

OBJECTIVE

The precise intra- vs. extradural localization of aneurysms involving the paraclinoid internal carotid artery is critical for the evaluation of patients being considered for aneurysm surgery. The purpose of this study was to investigate the clinical usefulness of T2-weighted three-dimensional (3-D) fast spin-echo (FSE) magnetic resonance (MR) imaging in the evaluation of unruptured paraclinoid aneurysms.

METHODS

Twenty-eight patients with unruptured cerebral aneurysms in their paraclinoid regions were prospectively evaluated using a T2-weighted 3-D FSE MR imaging technique with oblique coronal sections. The MR images were assessed for the location of the cerebral aneurysm in relation to the dural ring and other surrounding anatomic compartments, and were also compared with the surgical or angiographic findings.

RESULTS

All 28 aneurysms were identified by T2-weighted 3D FSE MR imaging, which showed the precise anatomic relationships in regards to the subarachnoid space and the surrounding anatomic structures. Consequently, 13 aneurysms were determined to be intradural and the other 15 were deemed extradural as they were confined to the cavernous sinus. Of the 13 aneurysms with intradural locations, three superior hypophyseal artery aneurysms were found to be situated intradurally upon operation.

CONCLUSION

High-resolution T2-weighted 3-D FSE MR imaging is capable of confirming whether a cerebral aneurysm at the paraclinoid region is intradural or extradural, because of the MR imaging's high spatial resolution. The images may help in identifying patients with intradural aneurysms who require treatment, and they also can provide valuable information in the treatment plan for paraclinoid aneurysms.

Temporary balloon occlusion during the surgical treatment of giant paraclinoid and vertebrobasilar aneurysms

PURPOSE

We propose the combined neurosurgical-endovascular treatment with the balloon occlusion of parent artery during surgery of giant paraclinoid and vertebrobasilar aneurysms, which are unsuitable for a pure endovascular or surgical approach.

METHODS

Between January 2003 and December 2007, we treated surgically 15 giant aneurysms (11 paraclinoid and four vertebrobasilar) with the combined approach of surgery and endovascular intraoperative technique.

FINDINGS

Complete aneurysm occlusion was achieved in all 15 aneurysms, as confirmed by intraoperative angiographic control. In one paraclinoid aneurysm, a small recurrence became evident 1 year after surgery and needed coil embolisation.

CONCLUSIONS

The temporary balloon occlusion technique is useful and improves the safety of the unavoidable exposure of the parent artery in the surgical treatment of giant paraclinoid and vertebrobasilar aneurysms.

Intraoperative monitoring of visual evoked potential: introduction of a clinically useful method

Object

To obtain a clinically useful method of intraoperative monitoring of visual evoked potentials (VEPs), the authors developed a new light-stimulating device and introduced electroretinography (ERG) to ascertain retinal light stimulation after induction of venous anesthesia.

Methods

The new stimulating device consists of 16 red light–emitting diodes embedded in a soft silicone disc to avoid deviation of the light axis after frontal scalp-flap reflection. After induction of venous anesthesia with propofol, the authors performed ERG and VEP recording in 100 patients (200 eyes) who were at intraoperative risk for visual impairment.

Results

Stable ERG and VEP recordings were obtained in 187 eyes. In 12 eyes, stable ERG data were recorded but VEPs could not be obtained, probably because all 12 eyes manifested severe preoperative visual dysfunction. The disappearance of ERG data and VEPs in the 13th eye after frontal scalp-flap reflection suggested technical failure attributable to deviation of the light axis. The criterion for amplitude changes was defined as a 50% increase or decrease in amplitude compared with the control level. In 1 of 187 eyes the authors observed an increase in intraoperative amplitude and postoperative visual function improvement. Of 169 eyes without amplitude changes, 17 manifested improved visual function postoperatively, 150 showed no change, and 2 worsened (1 patient with a temporal tumor developed a slight visual field defect in both eyes). Of 3 eyes with intraoperative VEP deterioration and subsequent recovery upon changing the operative maneuver, 1 improved and 2 exhibited no change. The VEP amplitude decreased without subsequent recovery to 50% of the control level in 14 eyes, and all of these developed various degrees of postoperative deterioration of visual function.

Conclusions

With the strategy introduced here it is possible to record intraoperative VEPs in almost all patients except in those with severe visual dysfunction. In some patients, postoperative visual deterioration can be avoided or minimized by intraoperative VEP recording. All patients without an intraoperative decrease in the VEP amplitude were without severe postoperative deterioration in visual function, suggesting that intraoperative VEP monitoring may contribute to prevent postoperative visual dysfunction.

Vascular anatomy: the head, neck, and skull base

Knowledge of the anatomy of the vasculature of the head and neck from the thorax to the skull base is critical to the approach to diagnosis and treatment of cerebrovascular disease. Awareness of the anatomic variations that may be encountered, common and uncommon, is necessary to avoid diagnostic pitfalls and to avert therapeutic disasters. Careful anatomic analysis and understanding of collateral pathways and dangerous anastomoses facilitates cross-sectional and angiographic diagnosis and the development of surgical and endovascular treatment strategies.

Microsurgical experience with supraorbital keyhole operations on anterior circulation aneurysms

OBJECTIVE

Conventional pterional approach is a commonly used neurosurgical technique for the treatment of cerebral aneurysms. However, this technique requires more extensive brain exposure than other key hole approaches and is sometimes associated with surgical traumatization or cosmetic problems. The aim of this study was to compare the postoperative outcome between pterional and supraorbital keyhole approaches in the patients with anterior circulation aneurysms.

METHODS

The authors reviewed patients with anterior circulation aneurysms who underwent aneurysm clipping via pterional or supraorbital keyhole approach at a single institute over a period of 2 years. Ninety-eight patients harboring 108 aneurysms were included in this study. Various outcomes were recorded, which included clinical grade, cosmetic problems, patients' satisfaction and complications such as chewing discomfort, frontal muscle weakness, hyposmia, infection.

RESULTS

The supraorbital approach exhibited a shorter operation time compared with the pterional approach. Complications such as chewing discomfort occurred less frequently in the supraorbital approach group. Moreover, the cosmetic outcome was significantly better in the supraorbital group than in the pterional group.

CONCLUSION

The supraorbital keyhole approach reduced intra- and postoperative complications, including chewing discomfort and cosmetic disturbances, compared with the conventional pterional approach.

PREOPERATIVE PREDICTIVE VALUE OF THE NECESSITY FOR ANTERIOR CLINOIDECTOMY IN POSTERIOR COMMUNICATING ARTERY ANEURYSM CLIPPING

OBJECTIVE

Resection of the anterior clinoid process (ACP) for the clipping of an internal carotid–posterior communicating artery aneurysm is rarely needed. However, preoperative awareness of the necessity of anterior clinoidectomy is essential for safe clipping of the lesions. We investigated the preoperative predictive value for anterior clinoidectomy in treating internal carotid–posterior communicating artery aneurysms.

METHODS

We retrospectively reviewed all patients with a posterior communicating artery aneurysm treated with clipping in the past 5 years. Only the patients who underwent both computed tomographic angiography and 4-vessel digital subtraction angiography were included in this study. We measured several angles and distances on these images, and compared the parameters measured between an anterior clinoidectomy group and a non–anterior clinoidectomy group. A P value of less than 0.05 was considered significant.

RESULTS

We examined 94 cases of posterior communicating artery aneurysms treated with clipping. The ACP was resected in 6 of the 94 cases. In the anterior clinoidectomy group, there were 3 factors that were statistically significant. First, the calculated real distance between the ACP and the aneurysmal neck was shorter (mean, 4.4 ± 0.7 versus 7.2 ± 1.4 mm). Second, the angle between vertical line to cranial base and communicating segment of the internal carotid artery (ICA) was larger (mean, 62.5 ± 4.6 versus 50.9 ± 10.7 degrees). Third, the angle between the communicating segment and the ophthalmic segment of the ICA was smaller (mean, 66.5 ± 15.1 versus 84.6 ± 20.4 degrees).

CONCLUSION

The anterior clinoidectomy group showed a more tortuous course of intracranial ICA around the ACP than the nonclinoidectomy group. Therefore, measurement of the distal ICA angle is helpful in predicting the necessity of anterior clinoidectomy.

Endovascular retrograde suction decompression as an adjunct to surgical treatment of ophthalmic aneurysms: analysis of risks and clinical outcomes

OBJECTIVE

Endovascular retrograde suction decompression with balloon occlusion of the internal carotid artery is a useful adjunct in the surgical treatment of ophthalmic aneurysms. This technique helps establish proximal control, facilitates intraoperative angiography, and may aid dissection by evacuating blood and softening the aneurysm. Although the technical aspects of this procedure have been described, the published data on its safety are scant. This study analyzed 2 groups of patients who underwent craniotomies for treatment of ophthalmic aneurysms, comparing a group who received suction decompression with a group who did not.

METHODS

A retrospective analysis of prospectively collected data on 118 craniotomies for ophthalmic aneurysms performed from 1990 to 2005 is presented. A group of 63 patients treated with endovascular suction decompression during surgery is compared with 55 patients who did not undergo this technique.

RESULTS

In our overall analysis of ophthalmic aneurysms, the clinical outcome was statistically related to aneurysm size (P = 0.046). The endovascular suction decompression group in this study had overall larger aneurysms (P < 0.0001) compared with the other group. There was no statistical difference between the 2 groups in rates of complications, stroke, new visual deficit, or death. The clinical outcomes were statistically similar at discharge and at 1 year.

CONCLUSION

Endovascular balloon occlusion and suction decompression did not increase the complication rate in a large cohort of craniotomy patients with ophthalmic aneurysms. This technique may be used to augment surgical capabilities without significantly increasing the operative risk.