The sizer-dissector for aneurysm clip selection: technical note

OBJECTIVE: Appropriate clip selection frequently becomes a matter of trial and error because of inadequate dissection of the pathway for each clip blade. To facilitate selection of the proper clip size, a series of dissectors have been designed that mimic the exact caliber of each category of Sugita clips. METHODS: Three lines of sizer-dissectors reflecting the wire size of the most commonly used Sugita clips were developed by attaching a single aneurysm clip blade to a rounded microdissector handle. Each sizer-dissector is scaled in millimeters and is available in straight and angled configurations. Once dissection is presumed to be complete, the device is passed through the pathway of the intended aneurysm clip blades, and the clip with the appropriate caliber and length for permanent occlusion is selected. RESULTS: During dissection and clip ligation of 83 aneurysms, the sizer-dissector was used to select the blade length in 16 lesions and the blade caliber in 5 lesions. There were no complications associated with deployment of the device. CONCLUSION: By use of the sizer-dissector before attempting clip placement, clip selection is facilitated, safety is enhanced, and clip wastage is reduced.     

Origin of the Drake fenestrated aneurysm clip

The development of the Drake fenestrated aneurysm clip is a study in the history of ideas. This communication outlines the conception and solution of a surgical problem involved with the clipping of large basilar tip aneurysms. Dr. Charles G. Drake's ability to modify old ideas and experiment with new ones was instrumental to the conceptual idea of a fenestrated clip. Dr. Frank H. Mayfield and Mr. George Kees, Jr. played essential roles in bringing the idea to a reality. The development of the fenestrated clip has added substantially to the armamentarium of the aneurysm surgeon in dealing with large and complex aneurysms.     

Clinical experience with the use of a temporary clip for intracranial aneurysm surgery. Analysis of eighteen cases

Summary Although the use of a temporary clip in intracranial aneurym surgery has been proposed by several Neurosurgeons in the past, its use today is not generally accepted. Modern surgical techniques have contributed to safer exposure and direct attack on the aneurysm. However, aneurysm surgery continues to be a challenge to the Surgeon and occasionally demands the use of a temporary clip.Eighteen cases operated on with the use of a temporary clip have been analysed. The occlusion time of the feeding vessel and location of the temporary clip have been related to the outcome. There was no relationship between occlusion time of the feeding vessel and outcome in this material, whereas location of the temporary clip seemed to be of importance for the outcome in cases with aneurysms located in the middle cerebral artery.     

Presurgical planning of feeder resection with realistic three-dimensional virtual operation field in patient with cerebellopontine angle meningioma

Background

To devascularize meningiomas, the precise location of tumor attachment must be known. However, when a cerebellopontine angle (CPA) meningioma is in contact with many surrounding structures, it can be difficult to distinguish the most vascularized attachment (MVA) from other contact surfaces.

Objective

To validate the usefulness of a virtual operation field (VOF) of a CPA meningioma by high-spatial-resolution three-dimensional computer graphics (hs-3DCG).

Methods

Presurgical simulation with VOF was performed for eight CPA meningiomas to assess the MVA and the appropriate route to the main feeder. For hs-3DCG, the necessary preoperative radiographic images were fused. A hybrid model of volume and surface rendering was created from the fused images. The simulation results were compared with the operative results, and the MVA estimation rate was compared between VOF and contrast-enhanced fast imaging employing steady-state acquisition.

Results

By using VOF, the point at which the main feeder penetrated the tumor was estimated in all cases, and using this information, the MVA was detected. All patients underwent resection of the main feeder in the same way as simulated preoperatively. Estimation rates of MVA were 37.5 % in CE-FIESTA and 100 % in VOF (p?=?0.02, Fisher’s exact test).

Conclusion

The hs-3DCG method was of sufficiently high quality to enable VOF of CPA meningioma. This method may facilitate estimation of MVA and the main feeder penetration point, and may aid in the determination of the most appropriate approach to the main feeder.     

Biocompatibility analysis of the Sundt-Kees booster clip and the Drake aneurysm clip. Technical note

A combination of the Sundt-Kees reinforcing aneurysm clip applied to a Drake aneurysm clip in a piggyback fashion was studied for possible defects due to corrosion and or tissue toxicity. These two clips, which are made of similar metal (301 stainless steel), showed little or no defects when immersed in 5% saline or when implanted in rats for 6 months. This study demonstrates that clips made of similar metals can be used piggyback in patients without ill effects provided that they are carefully handled to avoid any abrasion or misbends which could conceivably lead to corrosion.     

Revisit of aneurysm clip closing forces: comparison of titanium versus cobalt alloy clip

Although closing force of cobalt alloy clip is well studied, there is only little information of titanium alloy clip available in the literature. In the present study, we examined and compared closing forces of various types and points of cerebral titanium and cobalt aneurysm clips for cerebral aneurysms. Straight, temporary, bayonet, angled, and fenestrated titanium or cobalt alloy clips were tested by measuring the closing forces at various points along their blade length. Closing forces of all the tested clips linearly increased from tip to base of clip blades. Sugita Titanium II clips had bigger closing forces than Elgiloy clips in all type clips except for the temporary clips. The closing forces of Sugita Titanium II and Yasargil titanium clips were similar in straight permanent type clip although there were some differences in closing forces between other types of Sugita and Yasargil clips. Our data showed that the closing forces differed depending not only on manufacturers but also on materials and shapes.     

Evolution of the crossed-action intracranial aneurysm clip. Technical note

The helical coiled-spring aneurysm clip with crossed legs evolved from clips designed by Mayfield and Scoville. The problems encountered during its development stimulated an evaluation of metals used in neurosurgery, the creation of implant standards, and the use of metals with greater strength and tissue compatibility; these metals later proved to be safe during magnetic resonance imaging.     

Migration of an aneurysm clip to the sacral subarachnoid space

Case report  A 33-year-old woman was admitted for evaluation of vertigo. An unruptured fusiform aneurysm of left distal posterior inferior cerebellar artery was found and presumed to be the cause of her vertigo. The aneurysm was clipped using three clips and then the vertigo was relieved. However, she developed low back pain 53 months after the operation. On plain radiographic examination, a right-angled clip was found at the sacral level. Cerebral angiography revealed two clips remaining at the previous location and previous aneurysm was no longer visualized. Her symptom of back pain was resolved spontaneously over 2 weeks, and she is doing well without any particular inconvenience for following 72 months. Discussion  Clip loosening and migration is an extremely rare event in aneurysm surgery. If the aneurysm is secured and symptoms related to a migrated clip is resolved, the removal of one does not seem to be mandatory.     

Computed tomographic angiography in the evaluation of clip placement for intracranial aneurysm

Summary   Background. Computed tomographic angiography (CTA) has been shown to reliably detect aneurysms pre-operatively. The aim of this study was to compare the ability of post-operative CTA to detect aneurysmal remnants in connection with clip placement compared with digital subtraction angiography (DSA). Furthermore, special attention was paid to identifying factors influencing the image quality of CTA. Method. Between January 2005 and January 2006 a total of 76 patients with intracranial aneurysms were treated in our department. Thirty-two patients with a total of 33 clipped aneurysm were included in this study. All patients underwent CTA and DSA after surgery. Two investigators, each blinded to the classifications of the other, assessed image quality and clip placement. Findings. In three patients aneurysmal remnants could be detected with CTA and DSA. One 2-mm aneurysmal remnant was not clearly identified on CTA; two small (<2-mm) aneurysmal remnants were definitely not seen on CTA. A single titanium clip was used for aneurysmal clipping in 26 patients, two clips were needed in six patients and one aneurysm required three clips being used. Overall, use of one titanium clip tended to result in better image quality. In addition, clip-gantry angles between 30° and 60° tended to yield better image quality. Conclusion. Post-operatively, CTA can be recommended as a reliable non-invasive diagnostic tool only with optimal image quality and with this criterion up to 66% of the aneurysms can be evaluated. Titanium artefacts, especially in the important zone (<2 mm) around the clip in which small aneurysmal remnants can occur, can render adequate evaluation impossible. CTA image quality depends on the number of titanium clips used, but clip-gantry-angle does not significantly influence the image quality. Correspondence: Ioannis Pechlivanis, Department of Neurosurgery, Ruhr-University of Bochum, Knappschaftskrankenhaus, In der Schornau 23-25, 44892 Bochum, Germany.     

Migration of a Heifetz aneurysm clip to the cauda equina causing lumbar radiculopathy. Case report

A case is reported in which a Heifetz aneurysm clip, applied for the treatment of an aneurysm of the posterior inferior cerebellar artery, slipped and migrated into the cauda equina resulting in lumbar radiculopathy. Related reports are discussed briefly.