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Internal Thoracic Artery to Vertebral Artery Bypass Surgery: A Cadaveric Feasibility Study
Original Article
Internal Thoracic Artery to Vertebral Artery Bypass Surgery: A Cadaveric Feasibility Study Paul J. Schmitt1, Juan J. Altafulla1-3, Shogo Kikuta2, Graham Dupont2, Joe Iwanaga2,4, Stephen Monteith1, Zachary Litvack1, Aaron S. Dumont5, R. Shane Tubbs2,6
OBJECTIVE: Posterior circulation strokes account for over one quarter of all ischemic strokes. The frequency of vertebral artery origin stenosis (VAOS) in patients with vertebrobasilar insufficiency (VBI) has been estimated to be as high 26%e32%, and VAOS is the direct cause of posterior circulation strokes in 9% of patients. This association could have a significant genetic component. This study examines the feasibility of the internal thoracic artery (ITA) as a donor vessel for revascularization in patients with VAOS.
-
METHODS: Ten sides from 5 fresh-frozen white cadaveric necks derived from 3 women and 2 men were used in this study. The mean age of the cadavers at death was 77.2 years (range, 68e88 years). The subclavian artery, vertebral artery, and ITA were dissected. The length and diameter (proximal and distal) of the V1 segment and the length and diameter of the ITA were recorded. Finally, the ITA was transposed to the V1 segment of the vertebral artery (VA1).
-
RESULTS: The mean length of the VA1 and its diameter at the proximal and distal parts were 35.51 and 3.69 mm, respectively. The mean length and diameter of the ITA were 26.53 and 3.27 mm, respectively. Rerouting the ITA to the VA1 was feasible without tension on all sides.
-
CONCLUSIONS: This study indicates that the ITA is anatomically and hemodynamically an excellent option for bypass surgery in a VAOS scenario. We present convincing and reproducible data to aid neurosurgeons in choosing the procedure best suited to their patients.
-
Key words - Internal mammary artery - Revascularization - Transposition - Vascular - V1 segment Abbreviations and Acronyms ITA: Internal thoracic artery VA: Vertebral artery VA1: V1 segment of vertebral artery VAOS: Vertebral artery origin stenosis
INTRODUCTION
T
he internal thoracic artery (ITA), also known as the internal mammary artery, has gained popularity as the vessel of choice for coronary artery bypass, mainly because it has exhibited improved results and survival with minimal complications. This approach has left a substantial number of patients free of cerebrovascular and cardiac events while reducing the need for repeat revascularization.1 Nevertheless, in the setting of vertebral artery origin stenosis (VAOS), no universally accepted management algorithm for symptomatic patients has yet been established. Although endoluminal revascularization with angioplasty and/or stenting has seen a surge in popularity, there is still a role for surgical management. There are several options for surgical revascularization of the proximal vertebral artery (VA). Typically, the procedure can include any combination of VA endarterectomy (although this is rarely performed as a stand-alone procedure), vertebral to carotid transposition, and vertebral to carotid bypass with a free graft.2-6 The aim of this study is to determine whether the ITA is a feasible donor in cases of VAOS treated with in situ bypass grafting. MATERIALS AND METHODS Ten sides from 5 fresh-frozen white cadavers derived from 3 women and 2 men were used in this study. The mean age of the cadavers at death was 77.2 years (range, 68e88 years). The V1 segment of vertebral artery (VA1) was traced to where it enters the transverse foramen of the cervical vertebrae. The length and diameter of the VA1 at the proximal part (point of bifurcation from the subclavian artery) and the distal part (point of entry to the transverse foramen) were measured. The ITA was followed distally from its origin from the subclavian artery to the point where it passed under the clavicle; special care was taken not to perforate
From the 1Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, USA; 2Seattle Science Foundation, Seattle, Washington, USA; 3Department of Anatomical Sciences, St. George’s University, St. George’s, Grenada; 4Department of Neurosurgery, Tulane University, New Orleans, Louisiana, USA; 5Division of Gross and Clinical Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan; and 6 Neurosurgery Department, Hospital Santo Tomas, Panama To whom correspondence should be addressed: Joe Iwanaga, D.D.S., Ph.D. [E-mail: [email protected]] Citation: World Neurosurg. (2019) 130:e722-e725. https://doi.org/10.1016/j.wneu.2019.06.203 Journal homepage: www.journals.elsevier.com/world-neurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
e722
www.SCIENCEDIRECT.com
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.06.203
ORIGINAL ARTICLE PAUL J. SCHMITT ET AL.
Figure 1. Transposing the internal thoracic artery to the V1 segment of the vertebral artery. (A) Subclavian, vertebral, and internal thoracic arteries exposed. (B) Internal thoracic artery cut at the distal part. (C) Internal
the parietal pleura. The available length of the ITA and its diameter were measured. Next, the ITA was cut at the most distal part available. Subsequently, the distal edge of the ITA was transposed to any part of the VA1 to confirm the feasibility of revascularization without tension (Figures 1 and 2). RESULTS Among the 10 sides, the VA entered the C6 transverse foramen in 9 and C5 in 1. The mean length of the VA1 and its diameter at the proximal and distal parts were 35.51 mm (range, 21.7e53.1 mm), 3.41 1.20 mm (range, 2.11e5.76 mm), and 3.69 1.36 mm (range, 2.52e6.74 mm), respectively. The mean length and diameter of the ITA were 26.53 6.89 mm (range, 17.18e37.36 mm) and 3.27 0.41 mm (range, 2.67e3.91 mm). On all sides, rerouting the ITA to the VA1 was feasible without tension. There were no significant sex and side differences. No previous scars or pathology were found in the dissected area.
INTERNAL THORACIC TO VERTEBRAL ARTERY BYPASS SURGERY
thoracic artery transposed to the vertebral artery. 1 represents the vertebral artery, 2 represents the internal thoracic artery, and 3 represents the subclavian artery.
however, medical treatment followed by stenting would be the most common steps taken. The behavior of the stenosed VA differs from that of a carotid artery in that less stenosis is required before clinical manifestations are noted.6 Similarly, the efficacy of interventions such as medical management and stenting, as they are applied to carotid occlusive disease, is not as predictable in the vertebrobasilar circulation. Although there is growing enthusiasm for endovascular management of vertebrobasilar insufficiency, the results of randomized trials comparing stenting with medical management have been inconsistent.9-14
DISCUSSION Posterior circulation strokes account for over one quarter of all ischemic strokes.6 The frequency of VAOS in patients with vertebrobasilar insufficiency has been estimated to be as high as 26%e32%, and VAOS is the direct cause of posterior circulation strokes in 9% of patients. This association could have a significant genetic component.7 Although the natural history of VAOS is not entirely understood, there is evidence that it is an independent risk factor for posterior circulation stroke and early mortality.8,9 Similar to carotid stenosis, VAOS can be treated with medical management (antiplatelet agents), surgical revascularization (endarterectomy and/or bypass), and endovascular intraluminal revascularization (angioplasty and/or stenting). There is currently no consensus on the best treatment modality;
WORLD NEUROSURGERY 130: e722-e725, OCTOBER 2019
Figure 2. Schematic drawing of the transposition of the internal thoracic artery to the V1 segment of the vertebral artery.
www.journals.elsevier.com/world-neurosurgery
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ORIGINAL ARTICLE PAUL J. SCHMITT ET AL.
INTERNAL THORACIC TO VERTEBRAL ARTERY BYPASS SURGERY
VAOS The increase in stroke risk in patients with VAOS is probably attributable to a combination of hemodynamically significant arterial narrowing and embolic events. Whether posterior circulation strokes are primarily caused by artery-to-artery embolization or hypoperfusion remains unclear. The presence of VAOS is not universal in patients with vertebrobasilar insufficiency. Although VAOS entails a morbidity and mortality burden, its overall impact on the incidence of posterior circulation stroke could have been overestimated in previous series.8 The intraprocedural complications of endovascular treatment of VAOS include vessel injury, dissection, and thromboembolic events. The most common long-term complication is in-stent restenosis. The technical challenges of stenting the VAOS are inherent in the anatomic difficulties of stenting a vessel origin. Landing a stent in the VAOS requires that part of the stent extend into the parent vessel, obstructing the distal subclavian artery or hindering future endovascular access if treatment of restenosis becomes necessary. The highly elastic vertebral origin, coupled with the mobility of the vessel, could contribute to the high rates of in-stent restenosis in stented VAOS.15
ITA to the recipient vessel makes it a great option for posterior circulation revascularization.16 With this procedure, we aim to avoid common complications such as subclavian steal syndrome, injury and stenosing of a major vessel (common carotid), and Horner syndrome.17-19 Our measurements demonstrate that the ITA can be transposed to the V1 segment to serve as the donor vessel in an in situ bypass for VAOS because it shares hemodynamic properties and diameter (3.27 mm of internal thoracic vs. 3.69 and 3.41 mm of proximal and distal V1 segments, respectively) and the 2 are in proximity to each other. Finally, Otsuka et al.20 mentioned ITA grafts have higher longterm patency and increased survival rates when compared with great saphenous vein grafting. Additionally, ITA grafts are superior at 1 and 5 years compared with percutaneous stenting procedures. These authors also commented on the resistance of the ITA to atherosclerosis and that this might be because of characteristics such as having fewer fenestrations, lower permeability at intercellular junction permeability, and greater production of nitric oxide by the endothelium.20
ITA as a Donor Vessel Microsurgical revascularization for the treatment of VAOS has been well described.2,3,6,7,9 The technique described herein would primarily serve as an alternative when more traditional means of surgical revascularization are not possible. Flexibility, the ability to resist kinking and squashing, the ability to stretch, tensile and shear strength, and vessel diameter and length are key characteristics shared by V1 segments and the ITA. The proximity of the
REFERENCES 1. Sajja LR, Mannam G. Internal thoracic artery: anatomical and biological characteristics revisited. Asian Cardiovasc Thorac Ann. 2015;23: 88-99. 2. Berguer R, Bauer RB. Vertebral artery reconstruction. A successful technique in selected patients. Ann Surg. 1981;193:441-447. 3. Brasiliense LB, Albuquerque FC, Spetzler RF, Hanel RA. Advances and innovations in revascularization of extracranial vertebral artery. Neurosurgery. 2014;74(suppl 1):S102-S115. 4. Diaz FG, Ausman JI, de los Reyes RA, et al. Surgical reconstruction of the proximal vertebral artery. J Neurosurg. 1984;61:874-881. 5. Hanel RA, Brasiliense LB, Spetzler RF. Microsurgical revascularization of proximal vertebral artery: a single-center, single-operator analysis. Neurosurgery. 2009;64:1043-1050 [discussion: 1051]. 6. Rangel-Castilla L, Kalani MY, Cronk K, Zabramski JM, Russin JJ, Spetzler RF. Vertebral artery transposition for revascularization of the
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www.SCIENCEDIRECT.com
CONCLUSIONS Based on this study, the ITA is anatomically and hemodynamically an excellent option for bypass surgery in a VAOS scenario. We present convincing and reproductible data to aid neurosurgeons in choosing the procedure best suited to their patients. ACKNOWLEDGMENTS The authors thank those who donated their bodies for anatomic research.
posterior circulation: a critical assessment of temporary and permanent complications and outcomes. J Neurosurg. 2015;122:671-677. 7. Gordon Perue GL, Narayan R, Zangiabadi AH, et al. Prevalence of vertebral artery origin stenosis in a multirace-ethnic posterior circulation stroke cohort: Miami Stroke Registry (MIAMISR). Int J Stroke. 2015;10:185-187. 8. Thompson MC, Issa MA, Lazzaro MA, Zaidat OO. The natural history of vertebral artery origin stenosis. J Stroke Cerebrovasc Dis. 2014;23:e1-e4. 9. Al-Ali F, Barrow T, Duan L, et al. Vertebral artery ostium atherosclerotic plaque as a potential source of posterior circulation ischemic stroke: result from borgess medical center vertebral artery ostium stenting registry. Stroke. 2011;42: 2544-2549. 10. Coward LJ, McCabe DJ, Ederle J, et al. Long-term outcome after angioplasty and stenting for symptomatic vertebral artery stenosis compared with medical treatment in the Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS): a randomized trial. Stroke. 2007;38: 1526-1530.
11. Compter A, van der Worp HB, Schonewille WJ, et al. Stenting versus medical treatment in patients with symptomatic vertebral artery stenosis: a randomised open-label phase 2 trial. Lancet Neurol. 2015;14:606-614. 12. Stayman AN, Nogueira RG, Gupta R. A systematic review of stenting and angioplasty of symptomatic extracranial vertebral artery stenosis. Stroke. 2011; 42:2212-2216. 13. Sun X, Ma N, Wang B, et al. The long term results of vertebral artery ostium stenting in a single center. J Neurointerv Surg. 2015;7:888-891. 14. SSYLVIA Study Investigators. Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial Arteries (SSYLVIA): study results. Stroke. 2004;35:1388-1392. 15. Albuquerque FC, Fiorella D, Han P, Spetzler RF, McDougall CG. A reappraisal of angioplasty and stenting for the treatment of vertebral origin stenosis. Neurosurgery. 2003;53:607-614 [discussion: 614-616]. 16. Sarkar S, Schmitz-Rixen T, Hamilton G, Seifalian AM. Achieving the ideal properties for vascular bypass grafts using a tissue engineered
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.06.203
ORIGINAL ARTICLE PAUL J. SCHMITT ET AL.
approach: a review. Med Biol Eng Comput. 2007;45: 327-336. 17. Bohmfalk GL, Story JL, Brown WE, Marlin AE. Subclavian steal syndrome. Part 1: proximal vertebral to common carotid artery transposition in three patients, and historical review. J Neurosurg. 1979;51:628-640. 18. Borhani Haghighi A, Edgell RC, Cruz-Flores S, Zaidat OO. Vertebral artery origin stenosis and its treatment. J Stroke Cerebrovasc Dis. 2011;20: 369-376.
INTERNAL THORACIC TO VERTEBRAL ARTERY BYPASS SURGERY
19. Ziyal IM, Sekhar LN, Chandrasekar K, Bank WO. Vertebral artery to common carotid artery bypass in Takayasu’s disease with delayed cerebral ischemia. Acta Neurochir (Wien). 1999;141: 655-659. 20. Otsuka F, Yahagi K, Sakakury K, Vimani R. Why is the mammary artery so special and what protects it from atherosclerosis? Ann Cardiothorac Surg. 2013;2:519-526. Conflict of interest statement: The authors declare that the article content was composed in the absence of any
WORLD NEUROSURGERY 130: e722-e725, OCTOBER 2019
commercial or financial relationships that could be construed as a potential conflict of interest. Received 5 April 2019; accepted 27 June 2019 Citation: World Neurosurg. (2019) 130:e722-e725. https://doi.org/10.1016/j.wneu.2019.06.203 Journal homepage: www.journals.elsevier.com/worldneurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
www.journals.elsevier.com/world-neurosurgery
e725
Internal Thoracic Artery to Vertebral Artery Bypass Surgery: A Cadaveric Feasibility Study Paul J. Schmitt1, Juan J. Altafulla1-3, Shogo Kikuta2, Graham Dupont2, Joe Iwanaga2,4, Stephen Monteith1, Zachary Litvack1, Aaron S. Dumont5, R. Shane Tubbs2,6
OBJECTIVE: Posterior circulation strokes account for over one quarter of all ischemic strokes. The frequency of vertebral artery origin stenosis (VAOS) in patients with vertebrobasilar insufficiency (VBI) has been estimated to be as high 26%e32%, and VAOS is the direct cause of posterior circulation strokes in 9% of patients. This association could have a significant genetic component. This study examines the feasibility of the internal thoracic artery (ITA) as a donor vessel for revascularization in patients with VAOS.
-
METHODS: Ten sides from 5 fresh-frozen white cadaveric necks derived from 3 women and 2 men were used in this study. The mean age of the cadavers at death was 77.2 years (range, 68e88 years). The subclavian artery, vertebral artery, and ITA were dissected. The length and diameter (proximal and distal) of the V1 segment and the length and diameter of the ITA were recorded. Finally, the ITA was transposed to the V1 segment of the vertebral artery (VA1).
-
RESULTS: The mean length of the VA1 and its diameter at the proximal and distal parts were 35.51 and 3.69 mm, respectively. The mean length and diameter of the ITA were 26.53 and 3.27 mm, respectively. Rerouting the ITA to the VA1 was feasible without tension on all sides.
-
CONCLUSIONS: This study indicates that the ITA is anatomically and hemodynamically an excellent option for bypass surgery in a VAOS scenario. We present convincing and reproducible data to aid neurosurgeons in choosing the procedure best suited to their patients.
-
Key words - Internal mammary artery - Revascularization - Transposition - Vascular - V1 segment Abbreviations and Acronyms ITA: Internal thoracic artery VA: Vertebral artery VA1: V1 segment of vertebral artery VAOS: Vertebral artery origin stenosis
INTRODUCTION
T
he internal thoracic artery (ITA), also known as the internal mammary artery, has gained popularity as the vessel of choice for coronary artery bypass, mainly because it has exhibited improved results and survival with minimal complications. This approach has left a substantial number of patients free of cerebrovascular and cardiac events while reducing the need for repeat revascularization.1 Nevertheless, in the setting of vertebral artery origin stenosis (VAOS), no universally accepted management algorithm for symptomatic patients has yet been established. Although endoluminal revascularization with angioplasty and/or stenting has seen a surge in popularity, there is still a role for surgical management. There are several options for surgical revascularization of the proximal vertebral artery (VA). Typically, the procedure can include any combination of VA endarterectomy (although this is rarely performed as a stand-alone procedure), vertebral to carotid transposition, and vertebral to carotid bypass with a free graft.2-6 The aim of this study is to determine whether the ITA is a feasible donor in cases of VAOS treated with in situ bypass grafting. MATERIALS AND METHODS Ten sides from 5 fresh-frozen white cadavers derived from 3 women and 2 men were used in this study. The mean age of the cadavers at death was 77.2 years (range, 68e88 years). The V1 segment of vertebral artery (VA1) was traced to where it enters the transverse foramen of the cervical vertebrae. The length and diameter of the VA1 at the proximal part (point of bifurcation from the subclavian artery) and the distal part (point of entry to the transverse foramen) were measured. The ITA was followed distally from its origin from the subclavian artery to the point where it passed under the clavicle; special care was taken not to perforate
From the 1Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, USA; 2Seattle Science Foundation, Seattle, Washington, USA; 3Department of Anatomical Sciences, St. George’s University, St. George’s, Grenada; 4Department of Neurosurgery, Tulane University, New Orleans, Louisiana, USA; 5Division of Gross and Clinical Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan; and 6 Neurosurgery Department, Hospital Santo Tomas, Panama To whom correspondence should be addressed: Joe Iwanaga, D.D.S., Ph.D. [E-mail: [email protected]] Citation: World Neurosurg. (2019) 130:e722-e725. https://doi.org/10.1016/j.wneu.2019.06.203 Journal homepage: www.journals.elsevier.com/world-neurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
e722
www.SCIENCEDIRECT.com
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.06.203
ORIGINAL ARTICLE PAUL J. SCHMITT ET AL.
Figure 1. Transposing the internal thoracic artery to the V1 segment of the vertebral artery. (A) Subclavian, vertebral, and internal thoracic arteries exposed. (B) Internal thoracic artery cut at the distal part. (C) Internal
the parietal pleura. The available length of the ITA and its diameter were measured. Next, the ITA was cut at the most distal part available. Subsequently, the distal edge of the ITA was transposed to any part of the VA1 to confirm the feasibility of revascularization without tension (Figures 1 and 2). RESULTS Among the 10 sides, the VA entered the C6 transverse foramen in 9 and C5 in 1. The mean length of the VA1 and its diameter at the proximal and distal parts were 35.51 mm (range, 21.7e53.1 mm), 3.41 1.20 mm (range, 2.11e5.76 mm), and 3.69 1.36 mm (range, 2.52e6.74 mm), respectively. The mean length and diameter of the ITA were 26.53 6.89 mm (range, 17.18e37.36 mm) and 3.27 0.41 mm (range, 2.67e3.91 mm). On all sides, rerouting the ITA to the VA1 was feasible without tension. There were no significant sex and side differences. No previous scars or pathology were found in the dissected area.
INTERNAL THORACIC TO VERTEBRAL ARTERY BYPASS SURGERY
thoracic artery transposed to the vertebral artery. 1 represents the vertebral artery, 2 represents the internal thoracic artery, and 3 represents the subclavian artery.
however, medical treatment followed by stenting would be the most common steps taken. The behavior of the stenosed VA differs from that of a carotid artery in that less stenosis is required before clinical manifestations are noted.6 Similarly, the efficacy of interventions such as medical management and stenting, as they are applied to carotid occlusive disease, is not as predictable in the vertebrobasilar circulation. Although there is growing enthusiasm for endovascular management of vertebrobasilar insufficiency, the results of randomized trials comparing stenting with medical management have been inconsistent.9-14
DISCUSSION Posterior circulation strokes account for over one quarter of all ischemic strokes.6 The frequency of VAOS in patients with vertebrobasilar insufficiency has been estimated to be as high as 26%e32%, and VAOS is the direct cause of posterior circulation strokes in 9% of patients. This association could have a significant genetic component.7 Although the natural history of VAOS is not entirely understood, there is evidence that it is an independent risk factor for posterior circulation stroke and early mortality.8,9 Similar to carotid stenosis, VAOS can be treated with medical management (antiplatelet agents), surgical revascularization (endarterectomy and/or bypass), and endovascular intraluminal revascularization (angioplasty and/or stenting). There is currently no consensus on the best treatment modality;
WORLD NEUROSURGERY 130: e722-e725, OCTOBER 2019
Figure 2. Schematic drawing of the transposition of the internal thoracic artery to the V1 segment of the vertebral artery.
www.journals.elsevier.com/world-neurosurgery
e723
ORIGINAL ARTICLE PAUL J. SCHMITT ET AL.
INTERNAL THORACIC TO VERTEBRAL ARTERY BYPASS SURGERY
VAOS The increase in stroke risk in patients with VAOS is probably attributable to a combination of hemodynamically significant arterial narrowing and embolic events. Whether posterior circulation strokes are primarily caused by artery-to-artery embolization or hypoperfusion remains unclear. The presence of VAOS is not universal in patients with vertebrobasilar insufficiency. Although VAOS entails a morbidity and mortality burden, its overall impact on the incidence of posterior circulation stroke could have been overestimated in previous series.8 The intraprocedural complications of endovascular treatment of VAOS include vessel injury, dissection, and thromboembolic events. The most common long-term complication is in-stent restenosis. The technical challenges of stenting the VAOS are inherent in the anatomic difficulties of stenting a vessel origin. Landing a stent in the VAOS requires that part of the stent extend into the parent vessel, obstructing the distal subclavian artery or hindering future endovascular access if treatment of restenosis becomes necessary. The highly elastic vertebral origin, coupled with the mobility of the vessel, could contribute to the high rates of in-stent restenosis in stented VAOS.15
ITA to the recipient vessel makes it a great option for posterior circulation revascularization.16 With this procedure, we aim to avoid common complications such as subclavian steal syndrome, injury and stenosing of a major vessel (common carotid), and Horner syndrome.17-19 Our measurements demonstrate that the ITA can be transposed to the V1 segment to serve as the donor vessel in an in situ bypass for VAOS because it shares hemodynamic properties and diameter (3.27 mm of internal thoracic vs. 3.69 and 3.41 mm of proximal and distal V1 segments, respectively) and the 2 are in proximity to each other. Finally, Otsuka et al.20 mentioned ITA grafts have higher longterm patency and increased survival rates when compared with great saphenous vein grafting. Additionally, ITA grafts are superior at 1 and 5 years compared with percutaneous stenting procedures. These authors also commented on the resistance of the ITA to atherosclerosis and that this might be because of characteristics such as having fewer fenestrations, lower permeability at intercellular junction permeability, and greater production of nitric oxide by the endothelium.20
ITA as a Donor Vessel Microsurgical revascularization for the treatment of VAOS has been well described.2,3,6,7,9 The technique described herein would primarily serve as an alternative when more traditional means of surgical revascularization are not possible. Flexibility, the ability to resist kinking and squashing, the ability to stretch, tensile and shear strength, and vessel diameter and length are key characteristics shared by V1 segments and the ITA. The proximity of the
REFERENCES 1. Sajja LR, Mannam G. Internal thoracic artery: anatomical and biological characteristics revisited. Asian Cardiovasc Thorac Ann. 2015;23: 88-99. 2. Berguer R, Bauer RB. Vertebral artery reconstruction. A successful technique in selected patients. Ann Surg. 1981;193:441-447. 3. Brasiliense LB, Albuquerque FC, Spetzler RF, Hanel RA. Advances and innovations in revascularization of extracranial vertebral artery. Neurosurgery. 2014;74(suppl 1):S102-S115. 4. Diaz FG, Ausman JI, de los Reyes RA, et al. Surgical reconstruction of the proximal vertebral artery. J Neurosurg. 1984;61:874-881. 5. Hanel RA, Brasiliense LB, Spetzler RF. Microsurgical revascularization of proximal vertebral artery: a single-center, single-operator analysis. Neurosurgery. 2009;64:1043-1050 [discussion: 1051]. 6. Rangel-Castilla L, Kalani MY, Cronk K, Zabramski JM, Russin JJ, Spetzler RF. Vertebral artery transposition for revascularization of the
e724
www.SCIENCEDIRECT.com
CONCLUSIONS Based on this study, the ITA is anatomically and hemodynamically an excellent option for bypass surgery in a VAOS scenario. We present convincing and reproductible data to aid neurosurgeons in choosing the procedure best suited to their patients. ACKNOWLEDGMENTS The authors thank those who donated their bodies for anatomic research.
posterior circulation: a critical assessment of temporary and permanent complications and outcomes. J Neurosurg. 2015;122:671-677. 7. Gordon Perue GL, Narayan R, Zangiabadi AH, et al. Prevalence of vertebral artery origin stenosis in a multirace-ethnic posterior circulation stroke cohort: Miami Stroke Registry (MIAMISR). Int J Stroke. 2015;10:185-187. 8. Thompson MC, Issa MA, Lazzaro MA, Zaidat OO. The natural history of vertebral artery origin stenosis. J Stroke Cerebrovasc Dis. 2014;23:e1-e4. 9. Al-Ali F, Barrow T, Duan L, et al. Vertebral artery ostium atherosclerotic plaque as a potential source of posterior circulation ischemic stroke: result from borgess medical center vertebral artery ostium stenting registry. Stroke. 2011;42: 2544-2549. 10. Coward LJ, McCabe DJ, Ederle J, et al. Long-term outcome after angioplasty and stenting for symptomatic vertebral artery stenosis compared with medical treatment in the Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS): a randomized trial. Stroke. 2007;38: 1526-1530.
11. Compter A, van der Worp HB, Schonewille WJ, et al. Stenting versus medical treatment in patients with symptomatic vertebral artery stenosis: a randomised open-label phase 2 trial. Lancet Neurol. 2015;14:606-614. 12. Stayman AN, Nogueira RG, Gupta R. A systematic review of stenting and angioplasty of symptomatic extracranial vertebral artery stenosis. Stroke. 2011; 42:2212-2216. 13. Sun X, Ma N, Wang B, et al. The long term results of vertebral artery ostium stenting in a single center. J Neurointerv Surg. 2015;7:888-891. 14. SSYLVIA Study Investigators. Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial Arteries (SSYLVIA): study results. Stroke. 2004;35:1388-1392. 15. Albuquerque FC, Fiorella D, Han P, Spetzler RF, McDougall CG. A reappraisal of angioplasty and stenting for the treatment of vertebral origin stenosis. Neurosurgery. 2003;53:607-614 [discussion: 614-616]. 16. Sarkar S, Schmitz-Rixen T, Hamilton G, Seifalian AM. Achieving the ideal properties for vascular bypass grafts using a tissue engineered
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.06.203
ORIGINAL ARTICLE PAUL J. SCHMITT ET AL.
approach: a review. Med Biol Eng Comput. 2007;45: 327-336. 17. Bohmfalk GL, Story JL, Brown WE, Marlin AE. Subclavian steal syndrome. Part 1: proximal vertebral to common carotid artery transposition in three patients, and historical review. J Neurosurg. 1979;51:628-640. 18. Borhani Haghighi A, Edgell RC, Cruz-Flores S, Zaidat OO. Vertebral artery origin stenosis and its treatment. J Stroke Cerebrovasc Dis. 2011;20: 369-376.
INTERNAL THORACIC TO VERTEBRAL ARTERY BYPASS SURGERY
19. Ziyal IM, Sekhar LN, Chandrasekar K, Bank WO. Vertebral artery to common carotid artery bypass in Takayasu’s disease with delayed cerebral ischemia. Acta Neurochir (Wien). 1999;141: 655-659. 20. Otsuka F, Yahagi K, Sakakury K, Vimani R. Why is the mammary artery so special and what protects it from atherosclerosis? Ann Cardiothorac Surg. 2013;2:519-526. Conflict of interest statement: The authors declare that the article content was composed in the absence of any
WORLD NEUROSURGERY 130: e722-e725, OCTOBER 2019
commercial or financial relationships that could be construed as a potential conflict of interest. Received 5 April 2019; accepted 27 June 2019 Citation: World Neurosurg. (2019) 130:e722-e725. https://doi.org/10.1016/j.wneu.2019.06.203 Journal homepage: www.journals.elsevier.com/worldneurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
www.journals.elsevier.com/world-neurosurgery
e725