Surgery for paraclinoidal carotid artery aneurysms

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 < .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.

The avoidance of microsurgical complications in the extradural anterior clinoidectomy to paraclinoid aneurysms

OBJECTIVE

Paraclinoid segment internal carotid artery (ICA) aneurysms have historically been a technical challenge for neurovascular surgeons. The development of microsurgical approach, advances in surgical techniques, and endovascular procedures have improved the outcome for paraclinoid aneurysms. However, many authors have reported high complication rates from microsurgical treatments. Therefore, the present study reviews the microsurgical complications of the extradural anterior clinoidectomy for treating paraclinoid aneurysms and investigates the prevention and management of observed complications.

METHODS

Between January 2004 and April 2008, 22 patients with 24 paraclinoid aneurysms underwent microsurgical direct clipping by a cerebrovascular team at a regional neurosurgical center. Microsurgery was performed via an ipsilateral pterional approach with extradural anterior clinoidectomy. We retrospectively reviewed patients' medical charts, office records, radiographic studies, and operative records.

RESULTS

IN OUR SERIES, THE CLINICAL OUTCOMES AFTER AN IPSILATERAL PTERIONAL APPROACH WITH EXTRADURAL ANTERIOR CLINOIDECTOMY FOR PARACLINOID ANEURYSMS WERE EXCELLENT OR GOOD (GLASGOWS OUTCOME SCALE : GOS 5 or 4) in 87.5% of cases. The microsurgical complications related directly to the extradural anterior clinoidectomy included transient cranial nerve palsy (6), cerebrospinal fluid leak (1), worsened change in vision (1), unplanned ICA occlusion (1), and epidural hematoma (1). Only one of the complications resulted in permanent morbidity (4.2%), and none resulted in death.

CONCLUSION

Although surgical complications are still reported to occur more frequently for the treatment of paraclinoid aneurysms, the permanent morbidity and mortality resulting from a extradural anterior clinoidectomy in our series were lower than previously reported. Precise anatomical knowledge combined with several microsurgical tactics can help to achieve good outcomes with minimal complications.

Use of intracranial stenting to secure unstable liquid embolic casts in wide-neck sidewall intracranial aneurysms

BACKGROUND

Onyx HD 500 (eV3, Irvine, CA) is a high-viscosity liquid embolic agent that has recently been approved in the United States as a humanitarian use device for the treatment of wide-neck sidewall intracranial aneurysms. Preliminary evidence suggest that liquid embolic agents can provide improved angiographic results with a lower incidence of recanalization compared to coil embolization.

OBJECTIVE

To report unstable Onyx casts and how to deal with them.

METHODS

We report 4 cases of intracranial aneurysms treated with Onyx HD 500 in which, after the aneurysm was successfully obliterated, the Onyx cast was noted to have 1 of 2 types of embolic cast instability. In all 4 cases, an intracranial stent or vascular reconstruction device (VRD) was placed across the Onyx cast at the aneurysm orifice and the cast was stabilized.

CONCLUSION

This series is the first published description of Onyx HD 500 aneurysm cast instability. It is also the first report of using a stent or vascular reconstruction device rescue technique to secure an unstable Onyx cast and represents a new indication for these devices.

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.

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.

RESULTS, OUTCOMES, AND FOLLOW-UP OF REMNANTS IN THE TREATMENT OF OPHTHALMIC ANEURYSMS

OBJECTIVE

Ophthalmic aneurysms present unique challenges to a vascular team. This study reviews the 16-year experience of a multidisciplinary neurovascular service in the treatment, complications, outcomes, and follow-up of patients with ophthalmic aneurysms from 1990 to 2005.

METHODS

A retrospective analysis of prospectively collected data of 134 patients with 157 ophthalmic aneurysms is presented. Subgroup analysis is performed based on treatment and clinical presentation of the patients.

RESULTS

Clinical outcomes are reported using the Glasgow Outcome Scale. A “good” outcome is defined as a Glasgow Outcome Scale score of 4 or 5, and a “poor” outcome is defined as a Glasgow Outcome Scale score of 1 to 3. Outcome was related to patient age (P = 0.0002) and aneurysm size (P = 0.046). Outcomes for patients with ruptured aneurysms were related to hypertension (P &lt; 0.0001) and clinical admission grade (P = 0.001). In patients with unruptured aneurysms, a good clinical outcome was noted in 103 (92.7%) of 111 patients at discharge and 83 (94.3%) of 88 patients at the time of the 1-year follow-up evaluation. Complete clipping was attained in 89 (79.5%) of 112 patients with angiographic follow-up. Patients with aneurysm remnants from both coiling and clipping had a low risk of regrowth, and there were no rehemorrhages. One of 25 patients with angiographic follow-up (average, 4.3 ± 4.1 years) after “complete” clipping showed recurrence of the aneurysm.

CONCLUSION

Despite the difficulties presented by ophthalmic aneurysms, these lesions can be successfully managed by a multidisciplinary team. Imaging follow-up of patients is important, as there is a risk of aneurysm regrowth after either coiling or clipping.

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.

Long-term surgical results with aneurysms involving the ophthalmic segment of the carotid artery

Object

Because of the anatomical complexity of the paraclinoid region, the surgical treatment of aneurysms arising in the C6 segment of the internal carotid artery is extremely challenging. The authors' aim in this study was to describe the extended clinical follow-up and assess the short-term and long-term effectiveness of surgical treatment for these aneurysms, focusing on the clinical outcome and degree of aneurysm occlusion and recurrence.

Methods

The authors retrospectively analyzed the clinical records for patients treated surgically between 1973 and 2004 at the University of Rome, “La Sapienza.” Aneurysms were classified into the following 3 groups according to the site where they arose: the anteromedial, anterior or anterolateral, and posteromedial wall of the C6 segment.

Results

Of the 108 aneurysms in 104 patients treated, 63 (58%) were large or giant. Eighty-eight aneurysms in 84 patients were clipped, 16 underwent a high-flow bypass, 2 were trapped, 1 was wrapped, and 1 was left untreated. The mean follow-up was 126 months; 47 patients had a follow-up of > 10 years. Of the 88 aneurysms that were clipped, 6 (6.8%) had an incomplete occlusion that required an immediate reoperation in 1 case and at 2 years in another. Overall 6 patients (5.8%) had surgery-related permanent complications.

Conclusions

Mortality and morbidity rates depend mainly on the patient's preoperative Hunt and Hess grade subarachnoid hemorrhage, whereas surgical morbidity principally reflects excessive manipulation of the optic nerve or ischemic problems due to excessive temporary trapping undertaken without adequate neuroprotection. In expert hands, surgery (clipping and bypass procedures) is a definitive treatment for C6 aneurysms and has an acceptable complication rate.

Loss of visual evoked potential following temporary occlusion of the superior hypophyseal artery during aneurysm clip placement surgery. Case report

The authors report a case in which a 62-year-old woman with a history of subarachnoid hemorrhage due to a ruptured aneurysm was found to have a de novo paraclinoid aneurysm in the right internal carotid artery during a routine medical examination. Surgical clip placement was performed via a contralateral pterional approach under visual evoked potential (VEP) monitoring. The superior hypophyseal artery (SHA) was found to originate from the aneurysm body. The artery was temporarily occluded prior to application of the clip to the aneurysm neck. The VEP signal was lost 3 minutes after the SHA was occluded, and the potentials gradually recovered 10 minutes after the artery was released. The disappearance of VEP signal was reproducible with SHA occlusion. The clip was applied to the aneurysm body to preserve the origin of the SHA. The patient did not have any deterioration of vision after surgery. Intraoperative VEP monitoring can be used to help determine whether the SHA can be sacrificed safely.

Endoscopic endonasal clipping of an unsecured superior hypophyseal artery aneurysm

✓Paraclinoidal aneurysms, especially superior hypophyseal artery (SHA) aneurysms (with medial projection), can be challenging to access via a pterional craniotomy and damage to the optic nerve can occur during surgery. The authors have previously reported on endonasal clipping and aneurysmorrhaphy of a vertebral artery aneurysm following proximal and distal protection of the aneurysm using partial coil embolization. To the best of the authors' knowledge no unprotected aneurysm has been clipped using an endonasal approach.

The 56-year-old woman in this report was found to have two unruptured aneurysms: an anterior communicating artery (ACoA) aneurysm and an SHA aneurysm. An endoscopic endonasal, transplanar–transsellar approach was used to successfully clip the SHA aneurysm. Proximal and distal control was obtained endonasally prior to successful clip occlusion of the aneurysm. The ACoA aneurysm was clipped via a pterional craniotomy during the same anesthetic session. This report shows that it is possible to successfully clip a medially projecting, paraclinoidal aneurysm using an endonasal approach. Such cases must be chosen with extreme caution and only performed by surgeons with significant experience with both endoscopic endonasal approaches and neurovascular surgery.

Surgical anatomy of the anterior clinoid process

We studied the surgical anatomy of the anterior clinoid process (ACP) and its adjacent structures in cadaver heads. We paid special attention to the anatomical relationships between the ACP and adjacent structures to determine the surgical landmarks for safe anterior clinoidectomy. Thirty-five cadaver heads were dissected and the ACP regions were examined in 55 skull sides. We observed that in eight sides the ACP had been pneumatized from the sphenoid sinus. The caroticoclinoid foramen was revealed in only eight sides. The extra-ocular nerves ran forward to the superior orbital fissure at the inferolateral aspect of the ACP, with the oculomotor nerve being closest. The posterolateral area of the carotico-oculomotor membrane was thin and incomplete in nine sides. The study clarified the anatomical relationship between the ACP and its surrounding structures, and identified the major variations experienced. We used these to identify anatomical landmarks to assist the surgeon in the planning of a safe and effective anterior clinoidectomy.

Large ophthalmic segment aneurysms with anterior optic pathway compression: assessment of anatomical and visual outcomes after endosaccular coil therapy

Object

The optimal therapy for ophthalmic segment aneurysms with anterior optic pathway compression (AOPC) is undecided. Surgical results have been described, but the results of endovascular coil therapy have not been well documented.

Methods

The authors retrospectively reviewed data obtained in all patients who harbored unruptured ophthalmic segment aneurysms with AOPC who underwent endovascular coil therapy at their institution. They analyzed baseline and outcome visual function, aneurysm features, extent of aneurysm closure, internal carotid artery (ICA) occlusion, additional interventions, and neurological outcome.

In 17 patients (16 women), age 38 to 83 years, there were 28 affected eyes. All aneurysms were greater than 10 mm in diameter. In the initial procedures 16 of 17 patients received endosaccular coils and the ICA was preserved; in one patient the aneurysm was trapped and the ICA occluded. Patients then underwent follow up for a mean of 2.90 years (range 1 month–11.2 years) after the last procedure. One patient died of subarachnoid hemorrhage (SAH) 1 month postoperatively and thus no follow-up data were available for this case. Vision worsened in six patients, stabilized in four, and improved in six. Twelve patients underwent 13 subsequent procedures, including endovascular ICA occlusion in seven, repeated coil therapy in five, and optic nerve decompression in one; vision improved in 83% of these cases after ICA occlusion. A second patient died of SAH 5 months after repeated coil treatment. At the final follow up, vision had improved in eight patients (50%), stabilized in four (25%), and worsened in four (25%). In 16 patients with follow-up studies, aneurysm closure was complete in eight (50%) and incomplete in eight (50%).

Conclusions

The authors found that in patients with ophthalmic segment aneurysms causing chronic AOPC, endosaccular platinum coil therapy, with ICA preservation, may not benefit vision and that additional procedures may be needed. Evaluation of their results suggests that endovascular trapping of the aneurysm and sacrifice of the ICA appear to result in good visual, clinical, and anatomical outcomes.

Clinical manifestations and surgical results for paraclinoid cerebral aneurysms presenting with visual symptoms

BACKGROUND

Clipping a paraclinoid aneurysm is difficult if the patient has a visual disturbance. Visual function sometimes deteriorates postoperatively for patients with a large aneurysm. In this study, we report the long-term follow-up of patients with visual impairments attributed to optic nerve compression when paraclinoid aneurysms are surgically treated.

METHODS

Seventeen patients with optic nerve impairment induced by compression of paraclinoid ICA aneurysms were treated. All of the aneurysms were large, including 6 giant aneurysms. The aneurysms displayed partial thrombosis or calcification of the aneurysmal wall in 6 cases.

RESULTS

Direct surgery such as neck clipping or wrapping of the aneurysm was performed in 9 aneurysms and indirect procedures in 8 others (ICA occlusion, 1; ICA occlusion + bypass, 7). Of 17 patients, 11 (65%) showed improvement in several dysfunctions of visual acuity or visual field. Of 6 patients, whose vision had not recovered well, 5 underwent direct surgery. Moreover, these 5 patients had an intra-aneurysmal thrombosis or calcification of the aneurysmal wall. Nevertheless, 1 patient whose aneurysm with partial thrombosis was treated via indirect procedure had good recovery of vision.

CONCLUSIONS

Direct clipping is the treatment of choice for patients with a mass effect on the optic nerve due to paraclinoid aneurysm. However, it is difficult to achieve sufficient decompression of the optic nerve when the aneurysm is accompanied by partial thrombosis or calcification of the aneurysmal wall. In those cases, an indirect procedure seems to be a relatively safe, effective treatment.

Intracranial Aneurysms: an Overview

The outcome of intracranial aneurysms remains disastrous despite progress in diagnosis, management, care, and follow-up. This article discusses the pathology, the etiologies, the epidemiology and the classifications of intracranial aneurysms.

Surgical anatomy of the ophthalmic artery: its origin and proximal course

OBJECTIVE

We examined the surgical anatomy of the ophthalmic artery (OA) by dissection of cadaver heads, evaluating the anatomic relationships between the origin of the OA and both its proximal course and surrounding structures. In addition, we demonstrated the surgical application of these anatomic features for safe surgical exploration of this region.

METHODS

Through anatomic dissection, the origin of the OA was examined in both sides of 25 formalin-fixed and 10 fresh cadaver specimens. The following parameters were evaluated: the location of the origin of the OA in relation to the dural rings, the topographic relationship of the paraclinoid region, and the location of the dural penetrating point of the OA in the optic canal.

RESULTS

The OA originated from the internal carotid artery within the intradural space in 49% of cases, just above the upper dural ring in 37%, at the clinoid segment in 7%, and within the cavernous sinus in 6%. The dural penetrating point of the OA was anterior to the falciform ligament, and thereby in the optic canal, in 74% of cases, ventral to the falciform ligament in 19%, and posterior to the falciform ligament in 7%. The anterior circumference point of the upper dural ring, the point at which the upper dural ring intersects the anterior edge of the internal carotid artery, was more anterior to the falciform ligament in 40% of cases and ventral and posterior to the falciform ligament in 16.4% and 43.6%, respectively.

CONCLUSION

Our anatomic findings demonstrate anatomic variation of the OA in terms of its region of origin. Several anatomic points that were noteworthy during surgical exploration of this region are discussed.

Microneurosurgical management of carotid-ophthalmic aneurysms

OBJECTIVE

To evaluate the management of carotid-ophthalmic segment aneurysms (COA) with modern microneurosurgical techniques and instruments.

METHOD

Sixty patients with COA undergoing microsurgical clipping between March 1994 and June 2002 in the Department of Neurosurgery, Tiantan Hospital, Beijing, were analyzed retrospectively. Neuroimaging included digital subtraction angiography (DSA), MRI, CT, three-dimensional CT angiography and three-dimensional DSA. From 1998, intraoperative Doppler ultrasound monitoring and endoscope-assisted techniques were used.

RESULT

All aneurysms were completely obliterated without either recurrence or death. The morbidity rate of surgery prior to 1998 was 21.7%, which decreased to 13.7% after 1998 (mean 18.3% for the whole study period).

CONCLUSION

Preoperative planning based on neuroimaging is very valuable. Advances in neuroimaging, endoscope-assisted techniques and intraoperative Doppler ultrasound monitoring are useful to decrease postoperative complications. Microneurosurgical techniques are optimal for the management of COA with ever lessening morbidity.

Conventional microsurgical treatment of paraclinoid aneurysms: state of the art with the use of the selective extradural anterior clinoidectomy SEAC

Surgical treatment of paraclinoid aneurysms is considered to be difficult due to their complicated anatomical location in the vicinity of important neural, vascular and bony structures. We present our clinical experience of the past 10 years of conventional microsurgical treatment of 81 paraclinoid aneurysms in 75 patients with the use of selective extradural anterior clinoidectomy SEAC and discuss the method of therapy option by reviewing recent reports on results of endovascular coiling method and the combination of these with conventional microsurgical therapy. The favorable surgical results with the use of SEAC and no recurrence of the treated aneurysm after clipping procedure in our series indicate that direct surgery can still be a standard technique for paraclinoid aneurysms in view of the fact that the endovascular aneurysm coiling methods are still associated with a considerable percentage of incomplete occlusion and present the problem of coil packing.

Computer simulation of flow dynamics in paraclinoidal aneurysms

SUMMARY

Endovascular treatment, which is very useful method especially for paraclinoidal aneurysms, has the limitations of coil compaction and recanalization, which are difficult to predict. We tried to understand flow dynamic features, one of the important factors of such problems, using computer flow dynamics (CFD) simulations. CFD simulations were made in paraclinoidal aneurysm model of different size and protruded directions. Flow patterns, flow velocities and pressure are analyzed. Although the pressure on the aneurismal orifice is highest in the aneurysm protruding vertically - upward, the flow velocity is highest in the superior-medial protruding one. Significant difference is not observed in either flow patterns, flow velocities or pressures on the aneurismal orifices between the sizes of aneurismal sac. Among paraclinoidal aneurysms, an aneurysm protruding to superior-medially receives the most severe haemodynamic stresses at the orifice and the aneurysm size does not cause significant differences in the aspect of flow dynamics. It should be considered in the treatment of such aneurysms.

MRI location of the distal dural ring plane: anatomoradiological study and application to paraclinoid carotid artery aneurysms

The distal dural ring plane (DDRP) separates the intradural from the extradural paraclinoid internal carotid artery. The purpose of this study was to evaluate its position with MR imaging. The protocol used a T2-weighted sequence in two orthogonal planes: diaphragmatic (DIA-P) and carotid (CAR-P). The DDRP passes through four anatomoradiological reference points (RefP). We developed on a cadaveric model a correlation method supported by correlation lines and angles (CA) projecting the RefP toward the DDRP. RefP were correlated to the DDRP in 65-84% of cases in the DIA-P and 60-76% of cases in the CAR-P. CA were identified and correlated to the DDRP, respectively, in 87% and 60% of cases in the DIA-P, and 60% and 51% of cases in the CAR-P (failure often related to a lack of visibility of just one RefP). A higher tissular contrast in living subjects allowed the identification of CA in 90% and 80% of cases, respectively, in the DIA-P and the CAR-P. We propose that CA, when identified, should be considered as an approximation of the inferior radiological limit of the DDRP curve. In difficult angiographical cases, this MRI protocol could help to locate paraclinoid aneurysms on both sides of the cavernous sinus roof.

Large paraclinoid aneurysm with a calcified neck treated by tailored multimodality procedures

A 68-year-old woman presented with a large paraclinoid aneurysm with a calcified neck causing visual symptoms. Direct clipping was hazardous because of severe calcification of the neck. Endovascular internal trapping was difficult because of the short distance between the neck and the origin of the posterior communicating artery. Proximal occlusion was likely to be less effective because of large collateral back flow to the aneurysm via the ophthalmic artery (OphA). The aneurysm was successfully treated by a combination of a high-flow bypass, intraoperative coil embolization of the parent artery including the origin of the OphA, and clipping of the internal carotid artery distal to the aneurysm. Paraclinoid aneurysms may be difficult to treat by the simple application of direct clipping, endovascular coiling, or trapping. Multimodality procedures can be tailored to treat such aneurysms.

Temporary Aneurysm Orifice Balloon Occlusion as an Alternative to Retrograde Suction Decompression for Giant Paraclinoid Internal Carotid Artery Aneurysms: Technical Note

OBJECTIVE:

Giant paraclinoid carotid artery aneurysms frequently require the temporary interruption of local circulation to facilitate safe clip occlusion. Owing to the brisk retrograde blood flow through the ophthalmic artery and cavernous branches, the simple trapping of the aneurysm by cervical internal carotid artery clamping and intracranial distal clipping may not adequately soften the lesion. Retrograde suction decompression aspiration of this collateral supply by a catheter introduced into the cervical internal carotid artery is a popular method to achieve aneurysm deflation. With a large collateral supply, the method is not effective enough. The advent of relatively long and maneuverable soft balloons allows temporary occlusion of the aneurysm orifice.

METHODS:

We applied this method in two instances of giant carotid ophthalmic aneurysms. In both instances, a 15- to 20-mm-long and 4-mm-wide occlusion balloon was inserted in the internal carotid artery at the level of the aneurysm before craniotomy. After craniotomy and dissection of the aneurysm neck, the balloon was inflated under intraoperative angiographic control.

RESULTS:

The aneurysm became soft enough in both cases without tapping and aspiration to allow safe clip occlusion. In the first case, the postoperative course was uneventful and visual acuity improved. A known additional infraclinoid part of the aneurysm was eliminated endovascularly 5 months later using balloon-protected injection of vinyl alcohol copolymer (Onyx; Micro Therapeutics, Inc., Irvine, CA). In the second case, a postoperative symptomatic vasospasm developed 15 hours after surgery. Hypertensive therapy resulted in the disappearance of symptoms and an otherwise uneventful course with improvement of vision.

CONCLUSION:

This preliminary experience suggests that this new method is a feasible alternative to retrograde suction decompression.

Surgery for carotid dural ring aneurysms

BACKGROUND

Carotid aneurysms of the paraclinoid segment are usually located in the intradural space, but can infrequently straddle the intra- and extradural space.

CASE DESCRIPTION

We present 2 cases of unruptured carotid dural ring aneurysms with an aneurysmal sac that straddled the distal dural ring. Each paraclinoid aneurysm projected superiorly from the anterior surface of the internal carotid artery with a relatively flattened dome and central indentation on angiography. The aneurysmal domes were circumscribed by the distal dural ring and straddled the intra- and extradural space. After broad opening of the distal dural ring, aneurysms were successfully obliterated by clip application in parallel with the internal carotid artery.

CONCLUSION

These cases underscore the significance of an aneurysmal dome indentation on angiographic images as a reflection of aneurysmal circumscription by the distal dural ring. Aneurysms that straddle the intra- and extradural space may require broad opening of the distal dural ring for adequate control and clipping.

Balloon-assisted microvascular clipping of paraclinoid aneurysms

✓ Paraclinoid aneurysms represent a significant surgical challenge. Multiple techniques have been developed to maximize the effectiveness and safety of excluding these aneurysms from the cerebral circulation. Endovascular balloons have been used for proximal control of parent arteries during the treatment of aneurysms. In this report the authors describe the technique of navigating an endovascular balloon across the neck of paraclinoid aneurysms in four patients to gain proximal control, improve the accuracy of clip placement, and reduce the risk of distal embolization of intraluminal thrombus.

Six consecutive patients with giant or complex aneurysms of the ophthalmic or paraclinoid internal carotid artery that were not amenable to endovascular obliteration were retrospectively analyzed. In all six patients, the aneurysm was exposed and dissected for microsurgical clipping, and attempts were made to navigate a nondetachable, compliant silicone balloon across the neck of the aneurysm. If successfully placed, the balloon was inflated during clip placement. In four patients, the balloon was successfully navigated across the neck of the aneurysm and was inflated during clip application. Internal carotid artery tortuosity precluded navigation of the balloon into the intracranial circulation in two patients. All aneurysms were completely excluded from the parent vessel according to postoperative angiography studies. No complication occurred as a direct result of the endovascular portion of the procedure.

Endovascular balloon stenting of complex paraclinoid aneurysms during microvascular clipping may provide an adjunctive therapy that facilitates safe and accurate clip placement.

Extracorporeal femoral to carotid artery perfusion in selective brain cooling for a giant aneurysm

Giant partially thrombosed intracranial aneurysms are a challenge to treat surgically, and they are also unsuitable for coil embolization. The current options for treatment include extracranial-intracranial bypass followed by parent artery occlusion or direct surgical occlusion in which deep hypothermic circulatory arrest is used. The authors report the use of another approach in the treatment of a giant anterior circulation aneurysm: selective brain cooling accomplished by extracorporeal perfusion. This facilitated direct surgery on a 4.2-cm, partially thrombosed aneurysm of the middle cerebral artery (MCA). A brain temperature of 22 degrees C was achieved after 20 minutes of perfusion with blood cooled using an extracorporeal technique of femoral-common carotid artery perfusion. This was followed by a 20-minute period of surgical trapping of the MCA, then evacuation and clip occlusion of the aneurysm. During the period of selective brain cooling the patient's core body temperature was maintained above 35 degrees C. This technique of selective brain cooling may be a useful alternative to currently available surgical and endovascular methods of treatment for giant aneurysms.

Unruptured paraclinoid aneurysms: a management strategy

OBJECT

To elucidate an optimal managenent strategy for unruptured paraclinoid aneurysms, the authors retrospectively reviewed their experience in the treatment of 100 patients who underwent 112 procedures for111 paraclinoid aneurysms performed using direct surgery and/or endovascular treatment.

METHODS

Between 1997 and 2002, 111 unruptured paraclinoid aneurysms categorized according to a modified al-Rodhan classification (Group la, 30 anterior wall lesions; Group lb, 25 ventral paraclinoid lesions; Group IL 18 true ophthalmic artery lesions; Group III, 37 carotid cave lesions; and Group IV, one transitional lesion) were treated by direct surgery (35 lesions) and/or endovascular treatment (77 lesions) (one aneurysm was treated by both procedures). In lesions in Groups Ia, Ib, II, and III that were treated by endovascular treatment, complete aneurysm obliteration was achieved in 50, 65, 50, and 78%, respectively, and the combined transient and permanent morbidity rates due to cerebral embolic events were 20, 25, 20, and 13.9%, respectively. Overall, the transient morbidity rate after endovascular treatment was 14.3% and the permanent morbidity rate was 6.5%. Notably, permanent visual deficits caused by retinal embolism occurred after endovascular treatment in two patients with Group II aneurysms. Direct surgery was mainly performed in Groups Ia (20 lesions), Ib (five lesions), and II (eight lesions), with complete neck clip occlusion achieved in 80, 80, and 71.4%, respectively; the transient and permanent morbidity rates associated with aneurysms treated by surgery were 8.6 and 2.9%, respectively.

CONCLUSIONS

Endovascular therapy for superiorly projecting paraclinoid aneurysms (Groups Ia and II) is associated with lower rates of complete obliteration than direct surgery, and with rates of cerebral embolic events comparable to those of endovascular treatment in the other groups. Furthermore, endovascular treatment for Group II aneurysms entails additional risks of retinal embolism. Therefore, direct surgery is recommended for the treatment of paraclinoid aneurysms projecting superiorly. For other groups, especially for Group III, endovascular treatment is the acceptable first line of therapy.

Endovascular treatment of paraclinoid aneurysms: experience with 73 patients

OBJECTIVE

Aneurysms arising from the internal carotid artery in close relation to the clinoid process have been called paraclinoid aneurysms. The surgical management of these aneurysms poses technical challenges, and such patients are frequently referred for endovascular treatment. We reviewed our experience with endovascular coil embolization of paraclinoid aneurysms to evaluate the safety and efficacy of this treatment modality.

METHODS

From December 1993 to May 2002, 70 patients underwent endovascular procedures with detachable coils for 73 paraclinoid aneurysms (8 ruptured, 65 unruptured) at the University of Pittsburgh Medical Center and the University of Texas Southwestern Medical Center. A retrospective review of the medical records, outpatient charts, and operative reports was performed. Angiographic outcome was determined at the end of each procedure and by review of follow-up angiograms. Clinical assessments and outcomes are reported according to the Glasgow Outcome Scale (GOS).

RESULTS

Immediate angiographic outcomes for 73 paraclinoid aneurysms demonstrated complete occlusion in 53 (72.6%), near-complete occlusion in 6 (8.2%), and partial occlusion in 14 (19.2%). Nine aneurysms required more than one coiling session to complete treatment; 8 of these aneurysms required two sessions and 1 required four, for a total of 84 endovascular procedures. Follow-up angiograms could be obtained in 49 patients with 52 paraclinoid aneurysms. During the follow-up period, 6 aneurysms demonstrating partial occlusion and 3 demonstrating near-complete occlusion showed spontaneous progression of thrombosis to complete occlusion. Twelve aneurysms initially demonstrating complete occlusion (5 aneurysms), near-complete occlusion (3 aneurysms), or partial occlusion (4 aneurysms) showed coil compaction requiring retreatment. Of these 12 aneurysms that demonstrated coil compaction, 3 were treated with surgery and 9 with coil repacking. The final angiographic outcomes, determined on the last available follow-up angiograms of 49 aneurysms, excluding 3 surgically clipped aneurysms, showed complete occlusion in 43 (87.8%), near-complete occlusion in 3 (6.1%), and partial occlusion in 3 (6.1%). The angiographic follow-up period ranged from 4 to 54 months (mean, 13.9 mo). Morbidity and mortality rates related to 84 endovascular procedures were 8.3 and 0%, respectively. There were no recurrent or new subarachnoid hemorrhages in 63 patients in whom clinical follow-up could be performed during a mean clinical follow-up period of 14.4 months. The final clinical outcomes demonstrated a GOS score of 5 (good recovery) in 56 patients (88.9%), a GOS score of 4 (moderate disability) in 2 (3.2%), and a GOS score of 3 (severe disability) in 1 (1.6%). Four patients (6.3%) died of unrelated causes. The average period of hospitalization was 17.8 days in patients with acutely ruptured aneurysms and 3.5 days in patients with unruptured or retreated aneurysms.

CONCLUSION

The results of this study indicate that endovascular treatment is a safe and effective therapeutic alternative in ruptured and unruptured paraclinoid aneurysms. The endovascular treatment may also confer a positive impact in terms of the length of hospital stay.

[Giant supratentorial intracranial aneurysms. Analysis of 22 cases]

INTRODUCTION

Giant intracranial aneurysms represent 2 to 5% of all aneurysms. They are well characterized from the anatomical and clinical point of view. Their natural history shows its potential lethality. Surgical treatment of giant aneurysms is a challenge for neurosurgeons.

MATERIAL AND METHODS

Twenty-two patients were operated on through pterional craniotomy, specialized neuroanesthesia and microneurosurgical technics. Auxiliary methods like transitory clipping and retrograde decompression-suction technique were applied. Patients were followed at intensive care units and they were evaluated three months after the operation. Nineteen patients were in the fourth and sixth decade of life. Seventeen were females. Aneurysms were located at middle cerebral artery bifurcation; paraclinoidal carotid artery; proximal anterior cerebral artery and carotid bifurcation. Ninety one percent of aneurysms were clipped. Retrograde decompression-suction technique was performed in thirteen cases.

RESULTS

Seventeen patients had good outcome and one patient died (4.5%). There were 6 postoperative complications and in four disappeared three months later.

CONCLUSIONS

Giant aneurysms were operated on following main neurosurgical rules helped by auxiliar procedures to reduce aneurysms size and wall, aneurysms tension. New knowledge about giants aneurysms and the development of new techniques will permit better results.

Radiometric analysis of paraclinoid carotid artery aneurysms

OBJECT

Classification of paraclinoid carotid artery (CA) aneurysms based on their associated branching arteries has been confusing because superior hypophyseal arteries (SHAs) are too fine to appear opacified on cerebral angiograms. The authors performed a retrospective radiometric analysis of surgically treated paraclinoid aneurysms to elucidate their angiographic and anatomical characteristics.

METHODS

A retrospective analysis was made of 85 intradural paraclinoid aneurysms in which the presence or absence of branching arteries had been determined at the time of surgical clipping. The lesions were classified as supraclinoid, clinoid, and infraclinoid aneurysms based on their relation to the anterior clinoid process on lateral angiograms of the CA. The direction of the aneurysms were measured according to angles formed between the medial portion of the horizontal line crossing the aneurysm sac and the center of the aneurysm neck on anteroposterior angiograms. Branching arteries were associated with 68 aneurysms, of which 28 were ophthalmic artery (OphA) lesions (32.9%) and 40 were SHA ones (47.1%); associated branching arteries were absent in 17 aneurysms (20%). Twenty-five aneurysms (29.4%) were located at the supraclinoidal level, 46 (54.1%) at the clinoidal, and 14 (16.5%) at the infraclinoidal. The majority of aneurysms identified at the supraclinoidal level were OphA lesions (44%) or those unassociated with branching arteries (48%), with mean directions of 57 degrees or 67 degrees, respectively. At the clinoidal level, the mean directions of aneurysms were 76 degrees in six lesions unassociated with branching arteries (13%), 43 degrees in 16 OphA lesions (35%), and -11 degrees in 24 SHA ones (52%). All aneurysms at the infraclinoidal level arose at the origin of the SHAs, with a mean direction of -29 degrees, and most of these were embedded in the carotid cave.

CONCLUSIONS

Aneurysms arising from the SHA can be distinguished from those not located at an arterial division by cerebral angiography, because SHA lesions are usually located at the medial or inferomedial wall of the internal carotid artery at the clinoidal or infraclinoidal level. Their distribution correlates well with the reported distribution of SHA origins. The carotid cave aneurysm is a kind of SHA lesion that originates at the most proximal intradural CA.

Surgical repair of clinoidal segment carotid artery aneurysms unsuitable for endovascular treatment

OBJECTIVE

Clinoidal segment carotid artery aneurysms are surgically challenging lesions. The aneurysm neck originates proximal to the distal dural ring, and the aneurysms typically are larger. Therefore, endovascular techniques are often considered to be the primary treatment option. Treatment techniques and results for 40 clinoidal segment carotid artery aneurysms that were considered unsuitable for contemporary endovascular intervention are analyzed in this report.

METHODS

Forty aneurysms in 33 female and 3 male patients were treated surgically. Fifteen patients had bilateral aneurysms; of these patients, four underwent bilateral craniotomies. Twenty-seven aneurysms were 10 to 14 mm in size, eight were 15 to 24 mm, and five were more than 25 mm. The most common presentation was visual loss, which occurred in 13 patients. Seven patients presented with subarachnoid hemorrhage.

RESULTS

Thirty-seven aneurysms were directly repaired with clipping, two were trapped with bypass, and one was trapped without bypass. The complication rate was 10%, with one major stroke, two minor strokes, and one successfully treated brain abscess.

CONCLUSION

Surgical treatment of clinoidal segment carotid artery aneurysms can produce acceptable outcomes. Specific preoperative and intraoperative techniques facilitate improved surgical results for aneurysms that are not treatable with contemporary endovascular techniques.

Results after surgical and endovascular treatment of paraclinoid aneurysms by a combined neurovascular team

OBJECTIVE

Advances in surgical and endovascular techniques have improved treatment for paraclinoid aneurysms. A combined surgical and endovascular team can formulate individualized treatment strategies for patients with paraclinoid aneurysms. Patients who are considered to be at high surgical risk can be treated endovascularly to minimize morbidity. We reviewed the clinical and radiographic outcomes of 238 paraclinoid aneurysms treated by our combined surgical and endovascular unit.

METHODS

From 1991 to 1999, the neurovascular team treated 238 paraclinoid aneurysms in 216 patients at the Massachusetts General Hospital. The modality of treatment for each aneurysm was chosen based on anatomic and clinical risk factors, with endovascular treatment offered to patients considered to have higher surgical risks. One hundred eighty aneurysms were treated by direct surgery, 57 were treated by endovascular occlusion, and one was treated by surgical extracranial-intracranial bypass and endovascular internal carotid artery balloon occlusion. Locations were transitional, 12 (5%); carotid cave, 11 (5%); ophthalmic, 131 (55%); posterior carotid wall, 38 (16%); and superior hypophyseal 46 (19%). Lesions contained completely within the cavernous sinus were excluded from this analysis.

RESULTS

Using the Glasgow Outcome Scale (GOS), overall clinical outcomes were excellent or good (GOS 5 or 4), 86%; fair (GOS 3), 7%; poor (GOS 2), 4%; and death (GOS 1), 3%. Among the surgically treated patients, 90% experienced excellent or good outcomes (GOS 5 or 4), 6% had fair outcomes (GOS 3), 2% had poor outcomes (GOS 2), and 3% died (GOS 1). Among the endovascularly treated patients, 74% had excellent or good outcomes (GOS 5 or 4), 12% had fair outcomes (GOS 3), 10% had poor outcomes (GOS 2), and 4% died (GOS 1). The overall major and minor complication rate from surgery was 29%, with a 6% surgery-related permanent morbidity rate and a mortality rate of 0%. The overall major and minor complication rate from endovascular treatment was 21%, with a 3% endovascular-related permanent morbidity rate and a 2% mortality rate. Visual outcomes for patients who presented with visual symptoms were as follows: improved, 69%; no change, 25%; worsened, 6%; and new visual deficits, 3%. In general, angiographic efficacy was lower in the endovascular treatment group.

CONCLUSION

A combined team approach of direct surgery and endovascular coiling can lead to good outcomes in the treatment for paraclinoid aneurysms, including high-risk lesions that might not have been treated in previous surgical series.

Endovascular treatment of paraclinoid aneurysms

BACKGROUND

Paraclinoid aneurysms include those that are distal to the cavernous segment of the internal carotid artery and proximal to the posterior communicating artery. The purpose of this study was to review our experience with the endovascular treatment of this group of aneurysms, which are difficult to treat surgically.

METHODS

Between June 1994 and April 1999, 66 patients (56 female, 10 male) with a mean age of 50.1 years (range 13-75, median 51) underwent endovascular treatment for 71 paraclinoid aneurysms. The mean size of the dome was 8.9 mm (range 3-25 mm, median 7) and the of neck was 3.8 mm (range 1.4-8 mm, median 4). Thirteen patients presented with acute subarachnoid hemorrhage, and 4 with previous subarachnoid hemorrhage. Six aneurysms produced mass effect with visual symptoms, 4 presented with transient ischemic attacks, and 44 were incidental. Nine patients had had previous unsuccessful surgery. All procedures were performed under general anesthesia and with systemic heparinization.

RESULTS

Ninety endovascular procedures were performed on 71 aneurysms: GDC coiling in 78 (including 45 with the remodeling technique), permanent balloon occlusion in 9, and 3 had both GDC coiling and permanent balloon occlusion. In ten aneurysms it was not possible to place coils in the lumen of the aneurysm with the available technology and balloon occlusion was not indicated. Five of these were treated surgically and 5 remain untreated. All patients had immediate post procedure angiography. Of the 61 aneurysms that were treated, 46 (75%) have angiographic follow-up of 6 months or more. Morphological outcome following endovascular therapy for 61 aneurysms at last available follow-up showed > 95% occlusion in 52/61 (85.2%) and <95% in 9/61 (14.8%). Eight patients required surgery, 2 for partial coiling, 2 for refilling of a neck remnant, 2 for persistent mass effect and 2 for coil protrusion. In the 90 procedures performed, 2 (2.2%) patients had major permanent deficits (1 monocular blindness, 1 hemiparesis), 1 (1.1%) had a minor visual field cut, and 2 (2.2%) patients died from major embolic events.

CONCLUSION

Properly selected paraclinoid aneurysms can be successfully treated by endovascular technology. The morbidity and mortality rate of the endovascular approach in our experience is equal to or better than the published surgical series of similar aneurysms. We recommend that the endovascular approach be given primary consideration in the treatment of paraclinoid aneurysms.

Microsurgical anatomic features and nomenclature of the paraclinoid region

OBJECTIVE

We describe the detailed microsurgical anatomic features of the clinoid (C5) segment of the internal carotid artery (ICA) and surrounding structures, clarify the anatomic relationships of structures in this region, and emphasize the clinical relevance of these observations. Furthermore, because the nomenclature of the paraclinoid region is confusing and lacks standardization, this report provides a glossary of terms that are commonly used to descibe the anatomic features of the paraclinoid region.

METHODS

The region surrounding the anterior clinoid process was observed in 70 specimens from 35 formalin-fixed cadaveric heads. Detailed microanatomic dissections were performed in 10 specimens. Histological sections of this region were obtained from the formalin-fixed cadaveric specimens.

RESULTS

The clinoid segment of the ICA is the portion that abuts the clinoid process. This portion of the ICA can be directly observed only after removal of the clinoid process. The dura of the cavernous sinus roof separates to enclose the clinoid process. The clinoid segment of the ICA exists only where this separation of dural layers is present. Because the clinoid process does not completely enclose the ICA in most cases, the clinoid segment is shaped more like a wedge than a cylinder. The outer layer of the dura (dura propria) is a thick membrane that fuses with the adventitia of the ICA to form a competent ring that separates the intradural ICA from the extradural ICA. The thin inner membranous layer of the dura loosely surrounds the ICA throughout the entire length of its clinoid segment. The most proximal aspect of this membrane defines the proximal dural ring. The proximal ring is incompetent and admits a variable number of veins from the cavernous plexus that accompany the ICA throughout its clinoid segment.

CONCLUSION

The narrow space between the inner dural layer and the clinoid ICA is continuous with the cavernous sinus via an incompetent proximal dural ring. This space between the clinoid ICA and the inner dural layer contains a variable number of veins that directly communicate with the cavernous plexus. Given the inconstancy of the venous plexus surrounding the clinoid ICA, we think that categorical labeling of the clinoid ICA as intracavernous or extracavernous cannot be justified.

A combined transorbital-transclinoid and transsylvian approach to carotid-ophthalmic aneurysms without retraction of the brain

A series of 138 patients with 143 carotid-ophthalmic aneurysms (COAs) have been treated by direct surgical approach over the past 15 years. In 5 cases the COAs were bilateral and in 15 cases either one or more aneurysms were associated with a COA. Of the 143 COAs, 87 were small, 41 large and 15 were giant. Seventy-four COAs bled, while 69 were diagnosed either incidentally or else manifested themselves through neurological deficits resulting from compression of the adjacent structures by the aneurysms. Visual deficits were diagnosed in all the patients with large/giant COAs and in 27 patients with small COAs. Of the whole series of patients operated on for COAs, 2 died after surgery. Two patients had endocrinological deficits, 2 had hemiparesis, 36 had the same visual deficits as prior to surgery, whereas in 47 patients the visual function improved. Of all the 138 patients, 96 remained without neurological deficits, and the 36 patients with the same visual deficits as preoperatively also showed no neurological deficits after surgery and hence they were able to resume their previous way of life. Vasospasm did not occur in patients with COA(s) only, but was observed in 6 out of 15 patients with multiple aneurysms where subarachnoid hemorrhage (SAH) had occurred due to a rupture of an aneurysm other than the COA. There has been a major change in the surgical approach to COAs, from the classical pterional intradural approach to the transorbital-transclinoid and transsylvian approach which is described in this report. The latter approach provides ample space for proximal and distal control of the internal carotid artery (ICA) and makes it possible to deal with demanding large/giant COAs safely. In the series presented, there was no case of premature rupture of the aneurysm. Moreover, since we started using the described approach to COAs, retraction of the brain has not been necessary, regardless of the size of the aneurysm.

Clinoid and paraclinoid aneurysms: surgical anatomy, operative techniques, and outcome

BACKGROUND

Paraclinoid or ophthalmic segment aneurysms arise from the internal carotid artery (ICA) between the roof of the cavernous sinus and the origin of the posterior communicating artery. Clinoid aneurysms arise between the proximal and distal carotid dural rings. The complex anatomy of clinoid and paraclinoid ICA aneurysms often makes them difficult to treat by microsurgery. The natural history of these aneurysms varies, based on their location and anatomic relationships. Accurate preoperative assessment of the origin of these aneurysms is therefore a critical aspect of their management.

METHODS

The authors reviewed 35 clinoid and paraclinoid ICA aneurysms operated in 28 patients and classify them according to their anatomic location and angiographic pattern. The operative techniques, surgical outcomes, and indications for surgery are reviewed.

RESULTS

Based on surgical anatomy and angiographic patterns, the aneurysms were classified into two categories: clinoid segment and paraclinoid (ophthalmic) segment. The clinoid segment aneurysms consisted of medial, lateral and anterior varieties. The paraclinoid aneurysms could be classified topographically into medial, posterior and anterior varieties, or based on the artery of origin into ophthalmic, superior, hypophyseal, and posterior paraclinoid aneurysms. Ophthalmic aneurysms were most common (40%), followed by posterior ICA wall aneurysms (29%), superior hypophyseal aneurysms (14%), and clinoid aneurysms (17%). Twenty patients (71%) had single aneurysms. Of the remaining eight, six had bilateral aneurysms and two had unilateral multiple aneurysms. Of the 35 aneurysms, 32 were clipped satisfactorily, as confirmed by intraoperative or postoperative angiography. One small broad-based aneurysm was wrapped, and two others were treated by trapping and bypass techniques. Three patients who had bilateral aneurysms underwent successful clipping of four contralateral, left-sided aneurysms via a right frontotemporal, transorbital approach. On follow-up (mean, 39 months), 25 patients were in excellent condition (returned to their prior occupation), two were in good condition (independent, but not working), and one died postoperatively of vasospasm.

CONCLUSION

Our increased knowledge of anatomy and refinements in operative techniques have greatly improved the surgical treatment of clinoid and paraclinoid aneurysms.

A combined microsurgical skull-base and endovascular approach to giant and large paraclinoid aneurysms

BACKGROUND

The treatment of giant and large paraclinoid aneurysms remains challenging. To improve exposure, facilitate the dissection of aneurysms, assure vascular control, reduce brain retraction and temporary occlusion time, enable simultaneous treatment of associated lesions, and achieve more successful treatment of "difficult" (atherosclerotic and calcified) aneurysms, we combined the skull-base approach with endovascular balloon occlusion of the internal carotid artery (ICA) and suction decompression of the aneurysm.

METHODS

Sixteen female patients were treated, eight with giant aneurysms and eight with large aneurysms. Eight aneurysms occurred on the right side and eight on the left. Eight patients had an additional aneurysm; five were clipped during the same procedure. Three patients had infundibular arterial dilation. One patient had an associated hemangioma of the ipsilateral cavernous sinus. The cranio-orbital-zygomatic approach was used for all patients. The anterior clinoid was drilled, and the optic nerve was decompressed, dissected, and mobilized. Transfemoral temporary balloon occlusion of the ICA in the neck was followed by placement of a temporary clip proximal to the posterior communicating artery. Suction decompression was then applied. All aneurysms were then successfully clipped, except one that had a calcified neck and wall that could not be collapsed. Intraoperative angiography performed in 13 of 15 patients with clipped aneurysms confirmed obliteration of the aneurysm and patency of the blood vessels.

RESULTS

Postoperative results were good in 14 patients. One patient had right-sided hemiplegia and expressive aphasia, which improved after rehabilitation. One patient with an additional basilar tip aneurysm clipped simultaneously died on the fifth postoperative day because of intraventricular hemorrhage. The origin of bleeding could not be determined on autopsy. Surgical difficulties and morbidity stemmed mainly from a severely calcified or atherosclerotic aneurysmal neck.

CONCLUSION

The combination of skull-base approaches and endovascular balloon occlusion coupled with suction decompression is a successful option for the treatment of these challenging aneurysms.

Surgery of a large paraclinoid aneurysm with the support of coil embolization

SUMMARY

An attempt was made to clip the neck of a large paraclinoid aneurysm with the support of a balloon catheter, using a trapping-evacuation technique. The clip applied to the neck slipped off because of blood pressure through the posterior communicating artery which arose from the dome of the aneurysm. Therefore, using portable digital subtraction angiography (DSA) equipment, we placed interlocking detachable coils (IDCs) in the aneurysm for the purpose of reducing the intraaneurysmal pressure. Although the aneurysm was eventually trapped with two clips, this case indicates the supportive role of intravascular intervention in aneurysmal surgery when clipping an aneurysm or immediately after clip failure.

Unusual aneurysms of the distal internal carotid artery

BACKGROUND

Supraclinoid carotid aneurysms have traditionally been classified according to their relation to the major carotid branches, but considerable variation exists with respect to site of origin, projection, and relationship to the skull base. Distal internal carotid aneurysms with a superior or medial projection are uncommon vascular lesions, with an unusually high incidence of operative complications.

METHODS

Surgical experience with five patients suffering from subarachnoid hemorrhage due to ruptured aneurysms of the dorsomedial wall of the distal internal carotid artery is presented, with emphasis on their angiographic appearance, anatomical features, and operative management.

RESULTS

All five patients underwent surgical clipping. Intra-operative rupture occurred in two cases, with avulsion of the aneurysm from the internal carotid artery in both. A third patient experienced recurrent subarachnoid hemorrhage three days after uneventful surgery, due to the clip shearing off of the parent vessel.

CONCLUSIONS

Distal internal carotid aneurysms do not conform to the usual principles of aneurysm formation and are unique in their dorsomedial location unrelated to an arterial bifurcation. Although their anatomy is straightforward and exposure is not restricted by bone or dural structures of the skull base, they possess extremely fragile necks which make surgical management particularly hazardous.

Open surgery of giant paraclinoid aneurysms improved by intraoperative angiography and endovascular retrograde suction decompression

In three consecutive cases of giant left sided paraclinoid aneurysms we employed an endovascular retrograde suction decompression technique in combination with intra-operative angiography. A double-lumen balloon catheter was placed in the left internal carotid artery by the transfemoral route. After balloon inflation and placement of a temporary clip distal to the aneurysm blood was aspirated and the aneurysm collapsed. Thus further dissection of the aneurysm could easily be achieved and clips could be placed. Afterwards real-time digital subtraction angiography was performed. Intra-operative angiography led to clip repositioning in all cases either due to a clip induced stenosis of the parent vessel, or because of incomplete aneurysm obliteration. Afterwards successful clipping could be confirmed in all cases. Outcome was excellent in one case, good in the other. The third case, extremely complicated by an accompanying craniopharyngioma, showed a satisfactory outcome, but presented new neurological deficits.

Contralateral and ipsilateral microsurgical approaches to carotid-ophthalmic aneurysms

OBJECTIVE

The vicinity of carotid-ophthalmic aneurysms to the roof of the cavernous sinus, to the anterior clinoid process, and to the optic nerve or the optic chiasm requires well-defined surgical techniques. Although microsurgical techniques with ipsilateral direct approaches to these aneurysms have been described in detail, studies about contralateral strategies for the microsurgical treatment of carotid-ophthalmic aneurysms are rare and are mainly confined to case reports. The aim of this study is to describe how to decide on the ipsilateral and contralateral microsurgical approaches to such aneurysms and to demonstrate the surgical techniques for the ipsilateral and contralateral exposure of carotid-ophthalmic aneurysms.

METHODS

In a series of 51 patients with 58 aneurysms of the ophthalmic segment of the internal carotid artery, nine patients with 10 aneurysms (4 large aneurysms, 6 small aneurysms) were treated via a contralateral microsurgical approach after careful preoperative planning. Preoperative planning was based on the analysis of clinical and radiographic data, including cranial computed tomography, magnetic resonance imaging, magnetic resonance angiography, and conventional cerebral angiography.

RESULTS

The postoperative results were good in 38 (75%) of the patients, fair in 2 (4%), and poor in 3 (6%); 8 (15%) of the patients died after surgery. The postoperative follow-up was 4 months to 10 years. Postoperatively, 15 of 19 patients with uni- or bilateral visual deficits or visual field defects improved, 3 of the 19 patients experienced postoperative impairment of visual function, and 1 of the 19 patients had an unchanged visual field deficit. Visual impairment or unchanged visual function was observed in patients who underwent ipsilateral approaches, which was possibly caused by inappropriate intraoperative retraction of the optic nerve or chiasm. In all patients presenting with preoperative visual deficits who were treated via contralateral approaches, visual function improved in the postoperative course.

CONCLUSION

Giant carotid-ophthalmic aneurysms that are eligible for surgical treatment as well as small and large aneurysms dislocating the optic nerve or the chiasm superomedially or medially should be approached via ipsilateral craniotomies. It is recommended that small and large aneurysms of the carotid-ophthalmic segment originating medially, superomedially, or superiorly, displacing the optic nerve or the chiasm superiorly, superolaterally, or laterally, be approached via contralateral craniotomies.