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The tandem bypass: subclavian artery-to-middle cerebral artery bypass with dacron and saphenous vein grafts. Technical case report.
The Tandem Bypass: Subclavian Artery-to-Middle Cerebral Artery Bypass with Dacron and Saphenous Vein Grafts. Technical Case Report. Kurtis I. Auguste, A.B., Alfredo Quin ˜ ones-Hinojosa, M.D., and Michael T. Lawton, M.D. Department of Neurological Surgery, University of California, San Francisco School of Medicine, San Francisco, California
Auguste KI, Quin ˜ ones-Hinojosa A, Lawton MT. The “tandem bypass”: subclavian artery-to-middle cerebral artery bypass with Dacron and saphenous vein grafts. Technical case report. Surg Neurol 2001;56:164 –9. BACKGROUND
Fusiform or dolichoectatic intracranial aneurysms often cannot be managed with conventional surgical or endovascular techniques, and instead require trapping and revascularization techniques. On rare occasions in elderly patients, extracranial sites used for anastomosing the bypass have been previously repaired with synthetic vascular prostheses. This circumstance in an elderly subarachnoid hemorrhage patient led to a novel bypass procedure, the tandem bypass: a long extracranial-tointracranial bypass with two grafts of different materials assembled in series. CASE DESCRIPTION
A 71-year-old man with carotid artery atherosclerotic disease and a previous vascular reconstruction (subclavian artery-to-internal carotid artery Dacron interposition graft) presented with a subarachnoid hemorrhage from a dolichoectatic supraclinoid ICA aneurysm. The aneurysm was treated with trapping and distal revascularization. The final construct was a subclavian artery-to-middle cerebral artery bypass, with the graft being the previous Dacron prosthesis and a long saphenous vein. The vein graft was anastomosed end-to-side to the Dacron graft proximally, and end-to side to the middle cerebral artery distally. Subsequently, inflow to the aneurysm was occluded with clips on the Dacron graft beyond the proximal anastomosis of the vein graft, and outflow from the aneurysm was occluded with clips on the supraclinoid ICA. CONCLUSIONS
The tandem bypass, which uses prosthetic graft material and saphenous vein in succession, is a technically straightforward technique in patients who need extraAddress reprint requests to: Dr. Michael T. Lawton, Department of Neurological Surgery, University of California, San Francisco, 505 Parnassus Avenue, M-780, San Francisco, CA 94143-0112. Received November 22, 2000; accepted April 10, 2001. 0090-3019/01/$–see front matter PII S0090-3019(01)00484-0
cranial-to-intracranial bypasses and who also have preexisting carotid reconstructions or lack sufficient saphenous vein to complete a long bypass. © 2001 by Elsevier Science Inc. KEY WORDS
Cerebral revascularization, intracranial aneurysm, dolichoectatic, fusiform, subarachnoid hemorrhage, vascular anastomosis, tandem bypass.
nlike saccular aneurysms, fusiform or dolichoectatic aneurysms defy management with conventional surgical techniques because of their unusual anatomy and lack of a neck for clip or coil occlusion [6 –9,11,13,14]. These aneurysms often have thick, atherosclerotic walls [2–5] but nonetheless present frequently with subarachnoid hemorrhage in older patients [1,4,10,12]. Ruptured dolichoectatic aneurysms require treatment, and often the treatment requires proximal occlusion with revascularization to preserve blood flow to distal territories. When these aneurysms involve the proximal internal carotid artery, the proximal end of the bypass typically is connected extracranially in the neck. This combination of dolichoectatic aneurysms, elderly patients, and the need for cervical carotid artery bypass occasionally intersects with diffuse peripheral vascular disease and previous vascular repairs involving the cervical carotid artery, repairs that rely increasingly on synthetic vascular prostheses. We encountered one such patient who required a cervical carotid artery-to-middle cerebral artery bypass for a ruptured dolichoectatic supraclinoid internal carotid artery aneurysm, and who previously had his ipsilateral common carotid artery replaced
U
© 2001 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
The Tandem Bypass
Surg Neurol 165 2001;56:164 –9
Preoperative axial computed tomography scan (A) and T1-weighted magnetic resonance image (B) reveal thick subarachnoid hemorrhage in the left sylvian and ambient cisterns from rupture of the internal carotid artery aneurysm.
1
with a Dacron graft. Although the technical feasibility of suturing a saphenous vein into the prosthesis for the proximal anastomosis was never in question, no such undertaking had been reported previously for an extracranial-to-intracranial bypass. Therefore, we report our experience in this case with the tandem bypass: a Dacron graft in series with a saphenous vein graft as part of a long extracranial-to-intracranial bypass.
Case Report PRESENTATION A 71-year-old man presented to an outside emergency room with a sudden severe headache, confusion, and somnolence. His medical history was notable for peripheral vascular disease and coronary artery disease. Two years before this admission, his symptomatic left common carotid artery atherosclerotic disease was treated with a subclavian artery-to-internal carotid artery bypass using a Dacron interposition graft. On neurological exam, his eyes were closed but opened in response to pain. He tracked objects in his visual field, with intact extraocular muscle movements. His pupils were equal, round, and reactive to light. His grimace was symmetric. Gag and corneal reflexes were present. He localized pain with the left upper extremity, slightly flexed the right upper extremity, and withdrew both lower extremities symmetrically. Computed tomography (CT) scan and magnetic
resonance (MR) imaging demonstrated subarachnoid hemorrhage in the left carotid and sylvian cisterns, and hydrocephalus (Figure 1A,B). A cerebral angiogram demonstrated a dolichoectatic supraclinoid ICA aneurysm extending from the ophthalmic artery to the internal carotid artery bifurcation (Figure 2), which corresponded to the location of the subarachnoid blood. The midbasilar artery had some dolichoectatic dilatation, without aneurysmal changes, and no other aneurysms were identified. The patient was then transferred to our institution 5 days after his hemorrhage and taken to surgery 7 days after his hemorrhage. SURGICAL INTERVENTION A ventriculostomy was inserted into the right lateral ventricle and the patient was taken to the operating room. The aneurysm was exposed through a pterional approach, with mobilization of the temporalis muscle antero-inferiorly. The pterion and medial sphenoid ridge were drilled extensively and the dura was opened in a flap based on the pterion. The sylvian fissure was split and the internal carotid artery was exposed. The fusiform, dolichoectatic morphology of the aneurysm seen on angiography was confirmed by direct inspection (Figure 3A), and any attempt at direct clipping was abandoned. The alternative strategy was to revascularize the left middle cerebral artery (MCA) territory first with a saphenous vein bypass graft from the cervical carotid artery to the M2 MCA, and then to trap the aneurysm. The reconstructed cervical carotid artery was exposed through the previous incision in
166 Surg Neurol 2001;56:164 –9
Auguste et al
(A) Preoperative digital subtraction angiography demonstrates the Dacron graft from the subclavian artery to the internal carotid artery (ICA) on the left. Selective ICA injections demonstrate a dolichoectatic ICA aneurysm in the (B) anteroposterior and (C) lateral views.
2
the neck, with the Dacron graft lying deep to the sternocleidomastoid muscle and medial to the external jugular vein. The graft was followed rostrally to its anastomosis to the cervical ICA, which was too high for an anastomosis directly to the ICA. A 4-cm segment of the graft was prepared for the proximal saphenous vein anastomosis. The left saphenous vein was harvested through an incision that extended from the inguinal ligament down to the medial aspect of the left knee. The 30-cm segment of vein was marked with a Garrett line to prevent twisting, flushed with heparinized saline, and dilated at a pressure of 80 mm Hg. The sylvian fissure was split widely to expose the MCA bifurcation. The larger of the two M2 branches (frontal) was selected for the distal end-to-side anastomosis. The patient was given barbiturates, with the dose titrated to electroencephalographic burst suppression. Temporary clips were placed along a 1.5 cm segment of the MCA. The MCA frontal branch was perforated with a 27-gauge needle and the arteriotomy was extended with microscissors. The vein was anastomosed to the arteriotomy with a running 9-0 monofilament nylon suture (Figure 3B). The temporary clips were removed and retrograde filling of the vein up to the first valve and brisk arterial pulsations in the vein were observed. A 28 French chest tube was used to tunnel from the inferior aspect of the pterional incision to the cervical incision. A notch in the zygoma was drilled before tunneling. The saphenous vein was then placed in the tubing and pulled through to the cervical region. The proximal end of the saphenous
vein graft was sized for an end-to-side anastomosis to the Dacron graft. The patient was placed back into barbiturate-induced burst suppression and clamps were placed on the Dacron graft proximally and distally. A 1 cm opening was made in the Dacron graft (Figure 3C). The vein graft was spatulated so as to enlarge the orifice of the vein graft. The back wall of the anastomosis was sutured with 7-0 prolene run in continuous fashion to the other end of the arteriotomy (Figure 3D). The front wall of the anastomosis was completed with a second suture run continuously (Figure 3E). The clamps were removed from the Dacron graft and bypass flow to the MCA territory was established. The Dacron material was easily manipulated and handled the sutures well. Two Sugita aneurysm clips were placed on the Dacron graft just beyond the anastomosis to proximally occlude the aneurysm and remove any stump from the distal portion of the Dacron graft (Figure 4A). The distal supraclinoid ICA was exposed and occluded with a Sugita aneurysm clip placed just proximal to the anterior choroidal artery. This clip distally occluded the aneurysm and completed the trapping (Figure 4 B,C). The posterior communicating artery was clip occluded as it exited the aneurysm, leaving its branches to be supplied by vertebrobasilar flow. POSTOPERATIVE COURSE Postoperatively the patient became progressively more awake and arousable. He localized briskly with his upper extremities bilaterally and intermit-
The Tandem Bypass
Surg Neurol 167 2001;56:164 –9
(A) Intraoperative photographs demonstrate the dolichoectatic morphology of the proximal internal carotid artery (ICA) aneurysm. (B) The completed distal end-to-side anastomosis between the saphenous vein and the middle cerebral artery is shown, using a running suture. (C) An approximately 1-cm length of the Dacron graft was opened for the proximal anastomosis site. (D) The completed back wall of the proximal anastomosis can be seen as the front wall is being sutured. (E) The completed proximal end-to-side anastomosis is shown.
3
tently followed commands. He required placement of a ventriculoperitoneal shunt and was extubated 2 weeks postoperatively, after which he answered simple questions appropriately and interacted with family. During the next 5 months, the patient gradually returned to his baseline level of neurological function before his hemorrhage, performing activities of daily living independently and without difficulty. One year later, he had no residual neurological deficits or symptoms. He reported a higher
level of activity at last follow-up than before his hemorrhage.
Discussion The “tandem bypass” is described in this technical case report to treat a ruptured dolichoectatic proximal ICA aneurysm. The tandem bypass is composed of two graft conduits made of different mate-
168 Surg Neurol 2001;56:164 –9
Auguste et al
(A) Postoperative distal subtraction angiography of the proximal anastomosis is seen in the anteroposterior view. Note the contoured occlusion of the distal Dacron graft to eliminate a stump. (B) Intracranial lateral and (C) anteroposterior views demonstrate the distal anastomosis. Filling from the tandem bypass is both anterograde in the distal middle cerebral artery (MCA) territory and retrograde to supply the distal internal carotid artery and anterior cerebral artery. The aneurysm has been trapped with clips and no longer fills.
4
rials connected in series to bridge the donor and recipient sites. The subclavian artery-to-middle cerebral artery bypass has been described previously [15]. The novelty of this case is the previous common carotid replacement with a Dacron graft, which required that the cranial bypass be connected to this pre-existing prosthesis. To our knowledge, there are no published reports of extracranial-to-intracranial tandem bypasses such as this one. The use of two graft conduits in this tandem bypass is due to the fact that the carotid atherosclerotic disease and the intracranial aneurysm presented at different times. Had they presented simultaneously, a long saphenous vein graft from the subclavian artery to the MCA could have been used instead. It is somewhat surprising, considering that atherosclerotic disease and dolichoectatic aneurysms typically co-exist in older patients, that prior carotid artery repairs with vascular prostheses have not interfered more with the management of intracranial aneurysms with revascularization techniques. We did not find the Dacron graft to be difficult to manipulate. The material is firm but easily opened with standard surgical blades and scissors. Because of its firmness, the linear arteriotomy was widened to create an elliptical orifice into the vein graft before suturing the anastomosis. Standard 7-0 prolene suture, which is the usual suture for a similar anastomosis to a native carotid artery, was used without bending of the needle. An end-to-side anas-
tomosis was performed not because the distal ICA flow needed to be preserved, but because of the mismatch between the diameters of the Dacron graft and the proximal saphenous vein. The distal graft was occluded with aneurysm clips after the end-to-side anastomosis was completed, with care to contour the occlusion and eliminate any stump which could act as an embolic source. Although our strategy to manage this aneurysm with a tandem bypass and trapping of the aneurysm worked well, other options were available. The cervical ICA distal to the Dacron graft was considered as a proximal anastomosis site, but was high under the angle of the mandible and would have introduced some tortuosity into the vein graft’s course. The vein graft could have been anastomosed proximally to the subclavian artery, but this would have required a deep dissection in a scarred field, as well as a longer saphenous vein graft with increased risk to long-term patency. The petrous ICA is a potential proximal anastomosis site, with the advantage of a shorter vein graft and potentially longer patency. However, his ICA had an atherosclerotic appearance angiographically, which can sometimes make the artery less amenable to suturing. Another alternative would be to use the contralateral cervical ICA as the proximal site and run the graft across the neck. The graft would then be draped over the larynx without much soft tissue to protect it, and would have been susceptible to increased torque with head rotation. The tandem bypass seemed to be the best alternative, and it proved to be techni-
The Tandem Bypass
Surg Neurol 169 2001;56:164 –9
cally straightforward. Simple Hunterian ligation, or proximal carotid sacrifice without trapping or bypass, was not considered because it would not provide adequate protection against rerupture.
9. 10.
Conclusion The tandem bypass is a useful technique in patients with previous carotid artery repairs. Dacron is an accommodating recipient of saphenous vein grafts and should not impede the planned surgical revascularization. Furthermore, the tandem bypass might be useful in patients who do not have sufficient saphenous vein to complete a long bypass procedure.
11. 12. 13. 14. 15.
REFERENCES 1. Anson JA, Lawton MT, Spetzler RF. Characteristics and surgical treatment of dolichoectatic and fusiform aneurysms. J Neurosurg 1996;84:185–93. 2. Courville CB. Arteriosclerotic aneurysms of the circle of Willis. Some notes on their morphology and pathogenesis. Bull L A Neurol Soc 1962;27:1–13. 3. Dandy WE. Intracranial arterial aneurysms. New York: Hafner, 1944. 4. Hayes WT, Bernhardt H, Young JM. Fusiform arteriosclerotic aneurysm of the basilar artery. Five cases including two ruptures. Vasc Surg 1967;1:171– 8. 5. Housepian EM, Pool JL. A systematic analysis of intracranial aneurysms from the autopsy file of the Presbyterian Hospital, 1914 to 1956. J Neuropathol Exp Neurol 1958;17:409 –23. 6. Lawton MT, Hamilton MG, Morcos JJ, Spetzler RF. Revascularization and aneurysm surgery: current techniques, indications, and outcome. Neurosurgery 1996;38:83–94. 7. Lawton MT, Spetzler RF. Surgical management of giant intracranial aneurysms: experience with 171 patients. Clin Neurosurg 1995;42:245– 66. 8. Lawton MT, Spetzler RF. Surgical strategies for giant
intracranial aneurysms. Neurosurg Clin N Am 1998;9: 725– 42. Lawton MT, Spetzler RF. Surgical strategies for giant intracranial aneurysms. Acta Neurochir Suppl 1999; 72:141–56. Little JR, St. Louis P, Weinstein M, Dohn DF. Giant fusiform aneurysm of the cerebral arteries. Stroke 1981;12:183– 8. Newell DW, Skirboll SL. Revascularization and bypass procedures for cerebral aneurysms. Neurosurg Clin N Am 1998;9:697–711. Nishizaki T, Tamaki N, Takeda N, Shirakuni T, Kondoh T, Matsumoto S. Dolichoectatic basilar artery: a review of 23 cases. Stroke 1986;17:1277– 81. Onesti ST, Solomon RA, Quest DO. Cerebral revascularization: a review. Neurosurgery 1989;25:618 –29. Spetzler RF, Carter LP. Revascularization and aneurysm surgery: current status. Neurosurgery 1985;16: 111– 6. Spetzler RF, Rhodes RS, Roski RA, Likavec MJ. Subclavian to middle cerebral artery saphenous vein bypass graft. J Neurosurg 1980;53:465–9.
COMMENTARY
This article describes the authors’ experience with saphenous vein graft bypass between the middle cerebral artery and a Dacron prosthesis that had been implanted 2 years previously to treat a left common carotid artery atherosclerotic lesion. This case report is valuable because it shows that the Dacron prosthesis can be used as a recipient in later revascularization surgery. However, because long-term follow-up is not available at this point, this type of tandem bypass should be considered a last resort. Takashi Yoshimoto, M.D., Ph.D. Department of Neurosurgery Tohoku University Sendai, Japan
ne must never be in haste to end a day. There are too few of them in a lifetime.
O
—Dale Coleman
Auguste KI, Quin ˜ ones-Hinojosa A, Lawton MT. The “tandem bypass”: subclavian artery-to-middle cerebral artery bypass with Dacron and saphenous vein grafts. Technical case report. Surg Neurol 2001;56:164 –9. BACKGROUND
Fusiform or dolichoectatic intracranial aneurysms often cannot be managed with conventional surgical or endovascular techniques, and instead require trapping and revascularization techniques. On rare occasions in elderly patients, extracranial sites used for anastomosing the bypass have been previously repaired with synthetic vascular prostheses. This circumstance in an elderly subarachnoid hemorrhage patient led to a novel bypass procedure, the tandem bypass: a long extracranial-tointracranial bypass with two grafts of different materials assembled in series. CASE DESCRIPTION
A 71-year-old man with carotid artery atherosclerotic disease and a previous vascular reconstruction (subclavian artery-to-internal carotid artery Dacron interposition graft) presented with a subarachnoid hemorrhage from a dolichoectatic supraclinoid ICA aneurysm. The aneurysm was treated with trapping and distal revascularization. The final construct was a subclavian artery-to-middle cerebral artery bypass, with the graft being the previous Dacron prosthesis and a long saphenous vein. The vein graft was anastomosed end-to-side to the Dacron graft proximally, and end-to side to the middle cerebral artery distally. Subsequently, inflow to the aneurysm was occluded with clips on the Dacron graft beyond the proximal anastomosis of the vein graft, and outflow from the aneurysm was occluded with clips on the supraclinoid ICA. CONCLUSIONS
The tandem bypass, which uses prosthetic graft material and saphenous vein in succession, is a technically straightforward technique in patients who need extraAddress reprint requests to: Dr. Michael T. Lawton, Department of Neurological Surgery, University of California, San Francisco, 505 Parnassus Avenue, M-780, San Francisco, CA 94143-0112. Received November 22, 2000; accepted April 10, 2001. 0090-3019/01/$–see front matter PII S0090-3019(01)00484-0
cranial-to-intracranial bypasses and who also have preexisting carotid reconstructions or lack sufficient saphenous vein to complete a long bypass. © 2001 by Elsevier Science Inc. KEY WORDS
Cerebral revascularization, intracranial aneurysm, dolichoectatic, fusiform, subarachnoid hemorrhage, vascular anastomosis, tandem bypass.
nlike saccular aneurysms, fusiform or dolichoectatic aneurysms defy management with conventional surgical techniques because of their unusual anatomy and lack of a neck for clip or coil occlusion [6 –9,11,13,14]. These aneurysms often have thick, atherosclerotic walls [2–5] but nonetheless present frequently with subarachnoid hemorrhage in older patients [1,4,10,12]. Ruptured dolichoectatic aneurysms require treatment, and often the treatment requires proximal occlusion with revascularization to preserve blood flow to distal territories. When these aneurysms involve the proximal internal carotid artery, the proximal end of the bypass typically is connected extracranially in the neck. This combination of dolichoectatic aneurysms, elderly patients, and the need for cervical carotid artery bypass occasionally intersects with diffuse peripheral vascular disease and previous vascular repairs involving the cervical carotid artery, repairs that rely increasingly on synthetic vascular prostheses. We encountered one such patient who required a cervical carotid artery-to-middle cerebral artery bypass for a ruptured dolichoectatic supraclinoid internal carotid artery aneurysm, and who previously had his ipsilateral common carotid artery replaced
U
© 2001 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
The Tandem Bypass
Surg Neurol 165 2001;56:164 –9
Preoperative axial computed tomography scan (A) and T1-weighted magnetic resonance image (B) reveal thick subarachnoid hemorrhage in the left sylvian and ambient cisterns from rupture of the internal carotid artery aneurysm.
1
with a Dacron graft. Although the technical feasibility of suturing a saphenous vein into the prosthesis for the proximal anastomosis was never in question, no such undertaking had been reported previously for an extracranial-to-intracranial bypass. Therefore, we report our experience in this case with the tandem bypass: a Dacron graft in series with a saphenous vein graft as part of a long extracranial-to-intracranial bypass.
Case Report PRESENTATION A 71-year-old man presented to an outside emergency room with a sudden severe headache, confusion, and somnolence. His medical history was notable for peripheral vascular disease and coronary artery disease. Two years before this admission, his symptomatic left common carotid artery atherosclerotic disease was treated with a subclavian artery-to-internal carotid artery bypass using a Dacron interposition graft. On neurological exam, his eyes were closed but opened in response to pain. He tracked objects in his visual field, with intact extraocular muscle movements. His pupils were equal, round, and reactive to light. His grimace was symmetric. Gag and corneal reflexes were present. He localized pain with the left upper extremity, slightly flexed the right upper extremity, and withdrew both lower extremities symmetrically. Computed tomography (CT) scan and magnetic
resonance (MR) imaging demonstrated subarachnoid hemorrhage in the left carotid and sylvian cisterns, and hydrocephalus (Figure 1A,B). A cerebral angiogram demonstrated a dolichoectatic supraclinoid ICA aneurysm extending from the ophthalmic artery to the internal carotid artery bifurcation (Figure 2), which corresponded to the location of the subarachnoid blood. The midbasilar artery had some dolichoectatic dilatation, without aneurysmal changes, and no other aneurysms were identified. The patient was then transferred to our institution 5 days after his hemorrhage and taken to surgery 7 days after his hemorrhage. SURGICAL INTERVENTION A ventriculostomy was inserted into the right lateral ventricle and the patient was taken to the operating room. The aneurysm was exposed through a pterional approach, with mobilization of the temporalis muscle antero-inferiorly. The pterion and medial sphenoid ridge were drilled extensively and the dura was opened in a flap based on the pterion. The sylvian fissure was split and the internal carotid artery was exposed. The fusiform, dolichoectatic morphology of the aneurysm seen on angiography was confirmed by direct inspection (Figure 3A), and any attempt at direct clipping was abandoned. The alternative strategy was to revascularize the left middle cerebral artery (MCA) territory first with a saphenous vein bypass graft from the cervical carotid artery to the M2 MCA, and then to trap the aneurysm. The reconstructed cervical carotid artery was exposed through the previous incision in
166 Surg Neurol 2001;56:164 –9
Auguste et al
(A) Preoperative digital subtraction angiography demonstrates the Dacron graft from the subclavian artery to the internal carotid artery (ICA) on the left. Selective ICA injections demonstrate a dolichoectatic ICA aneurysm in the (B) anteroposterior and (C) lateral views.
2
the neck, with the Dacron graft lying deep to the sternocleidomastoid muscle and medial to the external jugular vein. The graft was followed rostrally to its anastomosis to the cervical ICA, which was too high for an anastomosis directly to the ICA. A 4-cm segment of the graft was prepared for the proximal saphenous vein anastomosis. The left saphenous vein was harvested through an incision that extended from the inguinal ligament down to the medial aspect of the left knee. The 30-cm segment of vein was marked with a Garrett line to prevent twisting, flushed with heparinized saline, and dilated at a pressure of 80 mm Hg. The sylvian fissure was split widely to expose the MCA bifurcation. The larger of the two M2 branches (frontal) was selected for the distal end-to-side anastomosis. The patient was given barbiturates, with the dose titrated to electroencephalographic burst suppression. Temporary clips were placed along a 1.5 cm segment of the MCA. The MCA frontal branch was perforated with a 27-gauge needle and the arteriotomy was extended with microscissors. The vein was anastomosed to the arteriotomy with a running 9-0 monofilament nylon suture (Figure 3B). The temporary clips were removed and retrograde filling of the vein up to the first valve and brisk arterial pulsations in the vein were observed. A 28 French chest tube was used to tunnel from the inferior aspect of the pterional incision to the cervical incision. A notch in the zygoma was drilled before tunneling. The saphenous vein was then placed in the tubing and pulled through to the cervical region. The proximal end of the saphenous
vein graft was sized for an end-to-side anastomosis to the Dacron graft. The patient was placed back into barbiturate-induced burst suppression and clamps were placed on the Dacron graft proximally and distally. A 1 cm opening was made in the Dacron graft (Figure 3C). The vein graft was spatulated so as to enlarge the orifice of the vein graft. The back wall of the anastomosis was sutured with 7-0 prolene run in continuous fashion to the other end of the arteriotomy (Figure 3D). The front wall of the anastomosis was completed with a second suture run continuously (Figure 3E). The clamps were removed from the Dacron graft and bypass flow to the MCA territory was established. The Dacron material was easily manipulated and handled the sutures well. Two Sugita aneurysm clips were placed on the Dacron graft just beyond the anastomosis to proximally occlude the aneurysm and remove any stump from the distal portion of the Dacron graft (Figure 4A). The distal supraclinoid ICA was exposed and occluded with a Sugita aneurysm clip placed just proximal to the anterior choroidal artery. This clip distally occluded the aneurysm and completed the trapping (Figure 4 B,C). The posterior communicating artery was clip occluded as it exited the aneurysm, leaving its branches to be supplied by vertebrobasilar flow. POSTOPERATIVE COURSE Postoperatively the patient became progressively more awake and arousable. He localized briskly with his upper extremities bilaterally and intermit-
The Tandem Bypass
Surg Neurol 167 2001;56:164 –9
(A) Intraoperative photographs demonstrate the dolichoectatic morphology of the proximal internal carotid artery (ICA) aneurysm. (B) The completed distal end-to-side anastomosis between the saphenous vein and the middle cerebral artery is shown, using a running suture. (C) An approximately 1-cm length of the Dacron graft was opened for the proximal anastomosis site. (D) The completed back wall of the proximal anastomosis can be seen as the front wall is being sutured. (E) The completed proximal end-to-side anastomosis is shown.
3
tently followed commands. He required placement of a ventriculoperitoneal shunt and was extubated 2 weeks postoperatively, after which he answered simple questions appropriately and interacted with family. During the next 5 months, the patient gradually returned to his baseline level of neurological function before his hemorrhage, performing activities of daily living independently and without difficulty. One year later, he had no residual neurological deficits or symptoms. He reported a higher
level of activity at last follow-up than before his hemorrhage.
Discussion The “tandem bypass” is described in this technical case report to treat a ruptured dolichoectatic proximal ICA aneurysm. The tandem bypass is composed of two graft conduits made of different mate-
168 Surg Neurol 2001;56:164 –9
Auguste et al
(A) Postoperative distal subtraction angiography of the proximal anastomosis is seen in the anteroposterior view. Note the contoured occlusion of the distal Dacron graft to eliminate a stump. (B) Intracranial lateral and (C) anteroposterior views demonstrate the distal anastomosis. Filling from the tandem bypass is both anterograde in the distal middle cerebral artery (MCA) territory and retrograde to supply the distal internal carotid artery and anterior cerebral artery. The aneurysm has been trapped with clips and no longer fills.
4
rials connected in series to bridge the donor and recipient sites. The subclavian artery-to-middle cerebral artery bypass has been described previously [15]. The novelty of this case is the previous common carotid replacement with a Dacron graft, which required that the cranial bypass be connected to this pre-existing prosthesis. To our knowledge, there are no published reports of extracranial-to-intracranial tandem bypasses such as this one. The use of two graft conduits in this tandem bypass is due to the fact that the carotid atherosclerotic disease and the intracranial aneurysm presented at different times. Had they presented simultaneously, a long saphenous vein graft from the subclavian artery to the MCA could have been used instead. It is somewhat surprising, considering that atherosclerotic disease and dolichoectatic aneurysms typically co-exist in older patients, that prior carotid artery repairs with vascular prostheses have not interfered more with the management of intracranial aneurysms with revascularization techniques. We did not find the Dacron graft to be difficult to manipulate. The material is firm but easily opened with standard surgical blades and scissors. Because of its firmness, the linear arteriotomy was widened to create an elliptical orifice into the vein graft before suturing the anastomosis. Standard 7-0 prolene suture, which is the usual suture for a similar anastomosis to a native carotid artery, was used without bending of the needle. An end-to-side anas-
tomosis was performed not because the distal ICA flow needed to be preserved, but because of the mismatch between the diameters of the Dacron graft and the proximal saphenous vein. The distal graft was occluded with aneurysm clips after the end-to-side anastomosis was completed, with care to contour the occlusion and eliminate any stump which could act as an embolic source. Although our strategy to manage this aneurysm with a tandem bypass and trapping of the aneurysm worked well, other options were available. The cervical ICA distal to the Dacron graft was considered as a proximal anastomosis site, but was high under the angle of the mandible and would have introduced some tortuosity into the vein graft’s course. The vein graft could have been anastomosed proximally to the subclavian artery, but this would have required a deep dissection in a scarred field, as well as a longer saphenous vein graft with increased risk to long-term patency. The petrous ICA is a potential proximal anastomosis site, with the advantage of a shorter vein graft and potentially longer patency. However, his ICA had an atherosclerotic appearance angiographically, which can sometimes make the artery less amenable to suturing. Another alternative would be to use the contralateral cervical ICA as the proximal site and run the graft across the neck. The graft would then be draped over the larynx without much soft tissue to protect it, and would have been susceptible to increased torque with head rotation. The tandem bypass seemed to be the best alternative, and it proved to be techni-
The Tandem Bypass
Surg Neurol 169 2001;56:164 –9
cally straightforward. Simple Hunterian ligation, or proximal carotid sacrifice without trapping or bypass, was not considered because it would not provide adequate protection against rerupture.
9. 10.
Conclusion The tandem bypass is a useful technique in patients with previous carotid artery repairs. Dacron is an accommodating recipient of saphenous vein grafts and should not impede the planned surgical revascularization. Furthermore, the tandem bypass might be useful in patients who do not have sufficient saphenous vein to complete a long bypass procedure.
11. 12. 13. 14. 15.
REFERENCES 1. Anson JA, Lawton MT, Spetzler RF. Characteristics and surgical treatment of dolichoectatic and fusiform aneurysms. J Neurosurg 1996;84:185–93. 2. Courville CB. Arteriosclerotic aneurysms of the circle of Willis. Some notes on their morphology and pathogenesis. Bull L A Neurol Soc 1962;27:1–13. 3. Dandy WE. Intracranial arterial aneurysms. New York: Hafner, 1944. 4. Hayes WT, Bernhardt H, Young JM. Fusiform arteriosclerotic aneurysm of the basilar artery. Five cases including two ruptures. Vasc Surg 1967;1:171– 8. 5. Housepian EM, Pool JL. A systematic analysis of intracranial aneurysms from the autopsy file of the Presbyterian Hospital, 1914 to 1956. J Neuropathol Exp Neurol 1958;17:409 –23. 6. Lawton MT, Hamilton MG, Morcos JJ, Spetzler RF. Revascularization and aneurysm surgery: current techniques, indications, and outcome. Neurosurgery 1996;38:83–94. 7. Lawton MT, Spetzler RF. Surgical management of giant intracranial aneurysms: experience with 171 patients. Clin Neurosurg 1995;42:245– 66. 8. Lawton MT, Spetzler RF. Surgical strategies for giant
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COMMENTARY
This article describes the authors’ experience with saphenous vein graft bypass between the middle cerebral artery and a Dacron prosthesis that had been implanted 2 years previously to treat a left common carotid artery atherosclerotic lesion. This case report is valuable because it shows that the Dacron prosthesis can be used as a recipient in later revascularization surgery. However, because long-term follow-up is not available at this point, this type of tandem bypass should be considered a last resort. Takashi Yoshimoto, M.D., Ph.D. Department of Neurosurgery Tohoku University Sendai, Japan
ne must never be in haste to end a day. There are too few of them in a lifetime.
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—Dale Coleman