TECHNICAL NOTE Repair of a Tear at the Base of a Blisterlike Aneurysm with Suturing and an Encircling Clip: Technical Note Kiyoyuki Yanaka, M.D., Ph.D., Kotoo Meguro, M.D., Tadao Nose, M.D., Ph.D. Department of Neurosurgery (KY, TN), Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki, and Department of Neurosurgery (KM), Tsukuba Medical Center, Tsukuba, Ibaraki, Japan OBJECTIVE: An aneurysm can produce large defects in the parent vessel if the aneurysm tears at the neck of the vessel. The authors present a technique to repair a tear at the base of a blister-like aneurysm encountered during microsurgical clipping of an anterior wall aneurysm of the internal carotid artery. METHODS: The repair technique involved suturing and covering the aneurysm with an encircling aneurysm clip. A large tear had destroyed the vessel’s tubular structure, and repair was not sufficient using an encircling clip alone. Two microsuture stitches were placed on the tear, so that a split artery re-formed a tubular structure. The lesion was then covered with Surgicel (Ethicon, Inc., Somerville, NJ) and fibrin glue. When the Surgicel and fibrin glue were applied, the temporary clip on the distal internal carotid artery was removed for a moment, allowing retrograde blood flow to provide the counterforce necessary to maintain the vessel’s tubular structure. An encircling clip was then applied to cover the entire circumference of the lesion. RESULTS: This method required only a short occlusion time for arterial repair, thus helping avoid ischemic complications. The patient awoke with transient hemiparesis, but recovery was prompt. CONCLUSION: This technique is useful for repairing an aneurysmal tear at its base, especially if the tear is large. (Neurosurgery 50:218–221, 2002) Key words: Aneurysm, Blister-like aneurysm, Clip, Internal carotid artery, Suturing, Wrapping A neurysms can produce large defects in the parent vessel if the aneurysm tears at the neck of the vessel. Vascular perforation can accidentally occur while arteries are manipulated during neurosurgery. Suturing or wrapping with hemostatic clips has been used to repair tears at the base of an aneurysm or to repair surgical damage to large intracranial vessels (2, 3, 12, 20). Several cases have been reported that describe successful arterial repair by suturing or vessel wrapping (9, 10, 19); however, disas218 trous outcomes have been reported in other cases owing to ischemia using such repair techniques (1, 13). Aneurysms arising from the anterior wall of the internal carotid artery (ICA), known as blood blister-like aneurysms, have been reported to have extremely thin, fragile walls with a marked tendency to rupture during microsurgery in the acute stage (1). Recently, we experienced an intraoperative arterial tear at the base of a blister-like aneurysm; the tear was successfully treated with Neurosurgery, Vol. 50, No. 1, January 2002 suturing and the application of an encircling clip. This technique required only a short period of occlusion. Aneurysmal rupture at the neck of the vessel does occur occasionally and can be treated using this same strategy. CASE REPORT A 46-year-old woman experienced a sudden-onset headache followed by loss of consciousness; she was transferred to our hospital by ambulance. Her neurological symptoms were unremarkable except for drowsiness. A computed tomographic scan showed a thin but diffuse subarachnoid hemorrhage predominantly on the right side. Angiographic studies performed on the day of onset demonstrated a faint bulge on the anteromedial wall of the right ICA (Fig. 1). With the aid of intraoperative angiography, a right pterional craniotomy was performed on the day of onset. The sylvian fissure was opened widely and the right frontal lobe was carefully elevated to expose the right ICA. The supraclinoid portion of the ICA was sclerotic. An extremely thin-walled aneurysm was seen on the anteromedial wall of the C1 segment (Fig. 2A), it and ruptured at its base during dissection. After temporary clips were applied on the proximal ICA and just before the ICA bifurcation, a curved Sugita clip was applied parallel to the arterial wall so that the clip blades could catch the arterial wall beyond the lesion (Fig. 2B). The clip controlled the bleeding from the base of the aneurysm, but the aneurysm then FIGURE 1. Preoperative right carotid angiogram, right anterior oblique view, showing a faint bulge on the anteromedial wall of the right ICA. Repair at the Base of a Blister-like Aneurysm FIGURE 2. Illustrations of suturing and clipping procedure. A, an aneurysm is seen on the anteromedial wall of the ICA. B, a curved clip is applied parallel to the arterial wall. C, the aneurysm is separated from its base. D, two temporary clips are applied to control bleeding. E, two nylon sutures are placed on the tear so that the split ICA re-forms a tubular structure. F, the lacerated arterial wall is covered with Surgicel and fibrin glue. The temporary clip on the distal ICA is removed to expand the lesion with retrograde blood flow. G, an encircling clip is placed to reinforce the entire lesion. An, aneurysm; PcomA, posterior communicating artery; AchoA, anterior choroidal artery; F, frontal lobe; T, temporal lobe. separated from its base with the clip intact (Fig. 2C). This separation created a large tear on the ICA that could not be repaired with any type of clip. Temporary clips were again applied to the ICA, with one clip just distal to the origin of the posterior communicating artery and one clip just proximal to the origin of the anterior choroidal artery (Fig. 2D). Two 8-0 nylon suture stitches were then placed on the tear so that the split ICA re-formed a tubular structure (Fig. 2E). The lacerated wall was then covered thinly with Surgicel (Ethicon, Inc., Somerville, NJ) and fibrin glue to completely seal the ICA. When the fibrin glue was applied, the temporary clip on the distal ICA was removed for a moment to expand the lesion with retrograde blood flow (Fig. 2F). An encircling clip with a Teflon liner (Heifetz clip No. 659-125; Mizuho Ika-Kogyo Co., Tokyo, Japan), 3.5 mm in diameter, was placed to reinforce the entire lesion (Fig. 2G). The total time of ischemia was approximately 19 minutes. Intraoperative angiography demonstrated a slight narrowing of the ICA, but the anterior and the middle cerebral arteries were well visualized (Fig. 3). Histological examination of the tissue corresponding to the aneurysmal dome revealed a simple blood clot with FIGURE 3. Intraoperative right carotid angiogram confirming the disappearance of the aneurysm and the patency of both the right middle and anterior cerebral arteries. fibrin, indicating that the wall of the aneurysm consisted of a hematoma and was not derived from the true arterial wall. Upon recovery, the patient exhibited a slight left hemiparesis. Angiography 10 days after surgery demonstrated moderate vasospasm in the right middle cerebral and posterior communicating arteries (Fig. 4). The patient made a prompt recovery and had returned to normal activities by 3 months after surgery. Neurosurgery, Vol. 50, No. 1, January 2002 219 FIGURE 4. Postoperative right carotid angiograms showing complete obliteration of the aneurysm. A, anteroposterior view; B, lateral view. Vasospasm on the middle cerebral and posterior communicating arteries is also demonstrated. DISCUSSION The usefulness of suturing and then applying an encircling clip to repair a tear at the base of an aneurysm is demonstrated. This method required only a short period of temporary occlusion of the ICA for arterial repair, thus helping to avoid ischemic complications. Aneurysms arising from the anterior wall of the ICA are rare, reportedly comprising 0.3 to 1% of all intracranial aneurysms (1). These have been classified into two groups: blister-like aneurysms and saccular-type aneurysms (9). They also have been described as distal medial wall aneurysms (19), dorsal ICA aneurysms (8), superior wall of the ICA aneurysms (3), and ICA trunk aneurysms (9). The aneurysms are generally located on the C1 or C2 segment of the ICA, project anteromedially, and are not related to the arterial bifurcation. The walls of blister-like aneurysms are extremely thin and fragile, with a marked tendency to rupture at the base during surgical treatment (1, 8). In a cadaveric study, it was demonstrated that these lesions are focal wall defects covered with thin fibrous tissue and are therefore not true aneurysms (3). Various neurosurgical tactics have been proposed to treat blister-like aneurysms. Careful dissection is recommended during surgery. If clipping is attempted, the clip should be applied with the clip blades parallel to the parent artery and catching the arterial wall beyond the lesion (5, 8). However, application of a clip that intentionally narrows the ICA 220 Yanaka et al. was reported to result in severe ischemic complications (9). Some authors have recommended wrapping to reinforce the fragile transitional zone rather than clipping (3, 8, 13). However, Ogawa et al. (9) demonstrated that wrapping did not prevent rebleeding and was associated with a high incidence of postoperative bleeding and death. Therefore, the treatment of this type of aneurysm requires special consideration. Several methods have been used to treat accidental vascular perforation. Because simple compression of a vessel covered with Surgicel and cottonoid is ineffective against a powerful bloodstream, several hemostatic clips act as a graft that is both carried and held in place by the clip providing a sutureless hemostasis. The clip can be applied quickly in the face of uncontrolled bleeding (7). Ishiwata et al. (4) reported on a Silastic encircling clip that can be tailored with scissors in the operating room. However, such clips cannot be applied if the tear is large and the vessel’s tubular structure is lost. Another method of achieving permanent hemostasis is the use of wrapping materials. Other reports have described the successful use of this method with materials such as gauze, muscle, muscle fascia, cellulose fabric, and Gore-Tex (W.L. Gore & Associates, Inc., Flagstaff, AZ) (8, 13, 14). Ogilvy et al. (10) reported another technique using Hemashield material (Boston Scientific/Medi-Tech, Natick, MA) in conjunction with a clip. Abe et al. (1) reported two cases in which wrapping with a strip of gauze could not prevent the growth of aneurysms. It appeared that wrapping with a strip of gauze was not sufficient to reinforce the very fragile aneurysm wall. Also, it is often difficult to select the most appropriate wrapping material and to cover the entire lesion with that wrapping material. Other reports have described refined microvascular suturing techniques for vessel repair (19). Okuchi et al. (11) reported the case of a blister-like aneurysm in which the laceration of the arterial wall was repaired with nylon thread. The total occlusion time for arterial repair was 50 minutes, resulting in a massive cerebral infarction. The suturing technique is often complicated by uncontrolled bleeding, the position of the vessel, and the friable vessel wall (7). In addition, such methods often require long periods of occlusion of the offending vessel and the clinical result is often less than optimal. Patients with disastrous outcomes due to ischemia during suturing have also been reported (1, 13). The repair of a tear on the ICA can be very difficult because the working space is deep and limited. Merely applying an encircling clip on the tear may not effectively achieve homeostasis. With a large tear, the tubular structure of the blood vessel can be lost, preventing the use of a clip. If the edges of the tear are far apart and fragile, manipulation with a suture or forceps would likely increase the size of the tear. In addition, if the vessel repair method is limited to suturing, the occlusion time of the ICA can become quite long. Under the above circumstances, we placed two 8-0 nylon microsuture stitches in the blood vessel to re-form the tubular structure rather than completely sealing the tear. This procedure took a fraction of the time that completely suturing the tear would have required. The lesion was then covered with Surgicel and fibrin glue. The temporary clip on the distal ICA was removed for a moment so that the retrograde blood flow could provide the counterforce necessary to maintain the vessel’s tubular structure. The collapsed vessel then returned to a tubular form suitable for the application of an encircling clip. An encircling clip was applied, covering the entire circumference of the blood vessel. This combined suture/encircling clip method may have resulted in a shorter occlusion time than suturing alone, thus avoiding potentially disastrous ischemic complications. Finally, the patency of the ICA was confirmed by intraoperative angiography. We have used angiography in the intraoperative assessment of various cerebrovascular procedures (15–18). This method was effective for confirming the patency of cerebral arteries during cerebral revascularization. We used the same suture/encircling clip technique in another patient during the microsurgical clipping of a ruptured aneurysm arising from the bifurcation of the left superior cerebellar artery and Neurosurgery, Vol. 50, No. 1, January 2002 the basilar artery. When approaching the aneurysm, we retracted the ICA backward to create a working space between the ICA and the optic nerve. The retractor slipped and tore the ICA wall, resulting in a massive hemorrhage. The tear was repaired using the suture/ encircling clip technique, and a good outcome was achieved. Therefore, this technique can be widely applied to repair accidental vessel damage. The Heifetz encircling clip was used in both patients. Such metal clips may be useful, provided that the segment of the ICA is free of branches or that the branch can be preserved using the window of the clip graft. Kawase et al. (6) recently developed a thin, flexible Silastic sheet for arterial repair (Vascwrap; Mizuho Ika-Kogyo Co.). The sheet is flexible and semitransparent, allowing observation of the area of perforation. It can also be easily tailored with scissors to prevent sacrificing a branching vessel. Such a device can be a useful alternative tool for vascular repair. It will benefit surgeons to have this type of clip or wrapping material (which is not generally available in modern aneurysm clip trays) available during surgery. In addition, suturing in a deep field requires long microsuture forceps and a microneedle holder. These surgical instruments should be prepared and available in the operating room. Although the situation described in this article does not occur often, a proper strategy to address such a problem can mean the difference between a good neurological outcome and an intraoperative catastrophe. Aneurysmal rupture at the neck of the vessel does occur occasionally and can be treated using the described suture/encircling clip strategy. ACKNOWLEDGMENT We are grateful to Ayuko Akagi of Brand of Cain (Sinjuku, Tokyo, Japan) for providing professional medical illustrations. Received, June 18, 2001. Accepted, July 26, 2001. Reprint requests: Kiyoyuki Yanaka, M.D., Ph.D., Department of Neurosurgery, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan. Email: kyanaka@md.tsukuba.ac.jp Repair at the Base of a Blister-like Aneurysm REFERENCES 1. Abe M, Tabuchi K, Yokoyama H, Uchino A: Blood blister-like aneurysms of the internal carotid artery. J Neurosurg 89:419–424, 1998. 2. Heifetz MD: A new intracranial aneurysm clip: Technical suggestion. J Neurosurg 30:753, 1969. 3. Ishikawa T, Nakamura N, Houkin K, Nomura M: Pathological consideration of a “blister-like” aneurysm at the superior wall of the internal carotid artery: Case report. Neurosurgery 40: 403–406, 1997. 4. 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Yanaka K, Tsuboi K, Fujita K, Aoki K, Takeuchi S, Anno I, Nose T: Distal anterior choroidal artery aneurysm associated with an arteriovenous malformation: Intraoperative localization and treatment. Surg Neurol 53:546–551, 2000. 19. Yaşargil MG: Microneurosurgery: Clinical Considerations, Surgery of the Intracranial Aneurysms and Results. Stuttgart, Georg Thieme, 1984, Vol II, pp 58–59. 20. Yokoo A, Sugita K, Kobayashi S, Matsuo K: A simple hemostatic method using a metal shield for injury of a major cerebral artery. J Neurosurg 57:323–327, 1982. COMMENTS The authors describe the expert management of an intraoperative misadventure during treatment of a blister-like aneurysm of the internal carotid artery. Although the precise pathophysiology of these unusual lesions is poorly understood, all who have dealt with them agree that they are potentially treacherous. The authors describe an elegant technique for successfully managing this intraoperative complication. The primary point of the article, however, is that the neurosurgeon managing these and other complex neurovascular disorders must remain flexible and creative. Particularly when dealing with blisterlike aneurysms, no single strategy is uniformly effective. In my own experience, most of these are best treated by encircling clips such as the Sundt clip graft, as there is often no reasonable neck at which a standard aneurysm clip can be used. If the aneurysm occurs adjacent to or opposite the origin of a perforating artery, the encircling clip will compromise the perforating vessel and is not a suitable solution. As pointed out by the authors, a variety of wrapping materials have been described; however, the long-term efficacy of wrapping remains questionable. When approaching these difficult lesions, the neurosurgeon should be prepared before the beginning the operation to remain highly flexible in dealing with a potential intraoperative catastrophe. This would include having encircling clips, wrapping materials, and a variety of aneurysm clips available. Preparations for performing an extracranial-to-intracranial bypass should also be made. Daniel L. Barrow Atlanta, Georgia Neurosurgery, Vol. 50, No. 1, January 2002 221 The amassed literature on blisterlike dorsal medial carotid aneurysms, this article included, should be enough evidence that traditional dissection and attempts at clip ligation carry an unacceptable morbidity. As the authors state in the Discussion, when faced with nothing more than a blood clot on the surface of the carotid artery, some form of sling (or, as I call it, “diaper”) secured with an aneurysm clip should be the primary strategy. If one is lucky enough to have Sundt’s so-called clip grafts handy, then certainly this technology should be utilized in a preemptive way. Steven L. Giannotta Los Angeles, California The authors present a surgical technique for treating a blister-like aneurysm. We have termed such aneurysms dorsal internal carotid artery aneurysms (1– 3). Clipping is difficult because these aneurysms are usually wide-based and thin-walled (1). The various surgical management protocols for these fragile aneurysms that we discussed (1) did not include the method that the authors describe in this article. In our cases, the edges of the torn artery were thin and often pathological with a dissecting nature, so that approximation by suture was difficult. The authors were fortunate to achieve their goal of forming a tubular vessel. The idea of this procedure is interesting and may be worth trying, but success should not be expected in all cases. Shigeaki Kobayashi Kazuhiro Hongo Tetsuyoshi Horiuchi Matsumoto, Japan 1. Kobayashi S, Hongo K, Shigeta H, Goel A: Dorsal internal carotid artery aneurysms, in Kobayashi K, Goel A, Hongo K (eds): Neurosurgery of Complex Tumors and Vascular Lesions. London, Churchill Livingstone, 1997, pp 37–46. 2. Kobayashi S, Kyoshima K, Orz Y: Blister-like aneurysms. J Neurosurg 89:419–424, 1998. 3. Nakagawa F, Kobayashi S, Takemae T, Sugita K: Aneurysms protruding from the dorsal wall of the internal carotid artery. J Neurosurg 65:303– 308, 1986.