- Email: [email protected]
Occipital Artery to Middle Cerebral Artery Bypass: Operative Nuances
Technical Note
Occipital Artery to Middle Cerebral Artery Bypass: Operative Nuances Toshikazu Kimura1 and Akio Morita2
BACKGROUND: Superficial temporal artery (STA)emiddle cerebral artery (MCA) anastomosis is a common procedure for vascular neurosurgeons, and it is used in a variety of diseases. However, there are cases in which the STA is absent or is too hypoplastic to be used as a donor for revascularization. Occipital artery (OA)eMCA bypass may be a treatment option in these cases.
-
METHODS: We encountered 4 cases of symptomatic cerebral ischemia in which the STA was absent or unavailable. These cases were treated by revascularization from the OA to the periphery of the MCA.
-
RESULTS: By meticulous dissection of the OA to the level of the superior temporal line, the OA could reach the periphery of the angular artery and be anastomosed to it in the usual fashion. The patency of the donor artery was confirmed by magnetic resonance angiography soon after the operation and 3 years later.
-
CONCLUSIONS: OA-MCA bypass may be a surgical option for cerebral revascularization when the STA is not available.
-
S
uperficial temporal artery (STA)emiddle cerebral artery (MCA) bypass is an established procedure used to treat a variety of diseases, such as cerebral ischemia, complex cerebral aneurysms, and neoplasms. However, in certain cases, the STA is absent or unavailable because of hypoplasia or a previous operation. In these cases, graft bypass is sometimes adapted using the radial artery, saphenous vein, occipital artery (OA), or other vessel, but graft bypass has several limitations, such as a need for complex procedures and the production of multiple surgical scars. In this article, we report use of the OA in
Key words Cerebral ischemia - EC-IC bypass - Moyamoya - OA-MCA bypass - Occipital artery -
Abbreviations and Acronyms DSA: Digital subtraction angiography MCA: Middle cerebral artery MRA: Magnetic resonance angiography OA: Occipital artery STA: Superficial temporal artery
WORLD NEUROSURGERY 108: 201-205, DECEMBER 2017
place of the STA for direct anastomosis and describe the technical nuances of this approach.
MATERIALS AND METHODS Between 2007 and 2015, 187 external-to-internal carotid artery bypasses were performed at our institution to treat moyamoya disease and hemodynamic ischemia because of atherosclerotic steno-occlusive disease of the major cerebral arteries. In ischemic steno-occlusive disease, the surgical indication was determined based on the criteria of the Japanese EC-IC Bypass Trial (JET study),1 assessing the cerebral blood flow using single-photon emission computed tomography with iodine123 N-isopropyl-iodoamphetamine accompanied by acetazolamide challenge when possible. Among the cases, OA-MCA bypass was performed in 4 cases (Table 1). One case involved ischemic moyamoya disease,2 and the other 3 involved atherosclerotic stenoocclusive disease. In the moyamoya case, the frontal branch of the STA had anastomosis with the anterior cerebral artery; hence, the parietal branch of the STA and OA was anastomosed to the M4 portion of the MCA. TECHNICAL NOTE During the operation, the patient was placed in the lateral position, with the head slightly rotated to the contralateral side, and the vertex was slightly elevated to reduce venous pressure. After confirming the course of the OA with Doppler sonography, a curved incision was made along the suboccipital and subgaleal segments of the OA. The OA was dissected from the galea under a microscope, from its periphery to the point where it pierces the splenius capitis muscle (Figure 1A). Retraction with a skin hook to open the incision slightly upward is useful to identify small branches of the OA because they exist in the same loose areolar tissue as the main trunk. Along the main trunk, one large branch can be identified in the subgaleal portion, which
From the 1Department of Neurosurgery, Japanese Red Cross Medical Center, Tokyo; and the 2 Department of Neurosurgery, Nippon Medical University, Tokyo, Japan To whom correspondence should be addressed: Toshikazu Kimura, M.D., Ph.D. [E-mail: [email protected]] Citation: World Neurosurg. (2017) 108:201-205. http://dx.doi.org/10.1016/j.wneu.2017.08.126 Supplementary digital content available online. Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2017 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
201
TECHNICAL NOTE
Table 1. Patient List Age (years)
Sex
Presentation
Preoperative Condition of STA
Single/Double
Site of First Anastomosis
Site of Second Anastomosis
Follow-Up Period (years)
1
54
M
Cognitive disturbance
Hypoplastic/retrograde via OA
Double
Angular
Post. temporal
5.4
2
30
F
Infarction (moyamoya)
Frontal br. fed cortex
STA parietal br. plus single OA
Posterior temporal
3
71
F
TIA
Already used
Double
Angular
Post. temporal
4.4
4
69
F
TIA
Cut in previous operation
Double
Angular
Post. temporal
3.1
Case
5.0
STA, superficial temporal artery; M, male; OA, occipital artery; F, female; Post. temporal, posterior temporal artery; br., branch; TIA, transient ischemic attack.
should be preserved for use as a conduit for rinsing inside the donor artery and for a second anastomosis (Figure 1B). To dissect the suboccipital portion of the OA, the sternocleidomastoid muscle was reflected anteriorly with the skin flap. The splenius capitis muscle was cut along the OA, and the upper part was also reflected anteriorly to make room for the guttering. The descending branches of the OA supplying the suboccipital muscles were dissected and cut after coagulation. Where the main trunk of the OA makes a hairpin curve, the connective tissue between the curve was dissected to stretch the OA during the anastomosis procedure. A concomitant vein was dissected from the OA to enhance the visibility and movability of the OA. By reflecting the longissimus capitis muscle inferiorly, the OA was exposed near the mastoid process. The incision was then extended anteriorly along the superior temporal line from the upper end of the vertical incision to perform the craniotomy. To prevent compression of the donor artery while the patient was lying supine, a gutter was made from the bottom of the craniotomy toward the proximal OA (Figure 1C). After manipulation of the bone, the OA was transected at the peripheral end, and its lumen was rinsed with heparin saline. Because the OA has few branches between the origin at the external carotid artery and the exposed suboccipital segment, heparin saline was injected to fill the proximal lumen, and the OA was occluded with an aneurysm clip to prevent clot formation. The length of the harvested OA was approximately 7 cm, and it was anastomosed to the periphery of the angular artery with intermittent sutures using 10-0 nylon (Figure 1D). Because the recipient artery was a peripheral artery, the diameter was smaller than the usual recipient M4 in STA-MCA bypass. Hence, the arteriotomy had to be a little longer than in the STAMCA bypass to ensure that the vessel walls met correctly. The other branch of the OA was anastomosed to the posterior temporal artery as well (Figures 1E and 1F and Video 1).
RESULTS The postoperative course was uneventful in all 4 cases. Magnetic resonance angiography (MRA) performed 3e5 years after the operation showed patency of the bypass in all 4 cases (Table 1).
202
www.SCIENCEDIRECT.com
Illustrative Cases Case 1. A 54-year-old man presented with dysarthria and confusion. He had a history of cerebral infarction in the right frontal lobe 9 years previously and had been on low-dose aspirin. Magnetic resonance imaging revealed a new infarction in the left basal ganglia and occlusion of the right internal carotid artery, which had already been noted. On digital subtraction angiography (DSA), there was also severe stenosis at the A1 segment of the left anterior cerebral artery. The right MCA area was perfused through a leptomeningeal anastomosis from a posterior cerebral artery. Single photon emission computed tomography showed decreased blood flow in the right parietal lobe. Acetazolamide challenge revealed a compromised vascular reserve in this area. Therefore, cerebral revascularization was recommended. The patient’s right STA was not palpable on physical examination. On DSA, the right OA had developed enough to supply the frontal area (Figure 2A); hence, direct OA-MCA bypass was performed. Postoperative DSA showed a patent bypass (Figure 2B), and the patient returned to his job 5 months after the operation. MRA performed 3 years later showed patency of the bypass (Figure 2C).
Case 3. A 71-year-old woman presented with a transient ischemic attack of motor aphasia and right hemiparesis. She had undergone an STAeanterior cerebral artery bypass for a minor stroke in the anterior cerebral artery region (Figure 1G) and had been taking 100 mg of aspirin daily. Because MRA showed severe stenosis at the M1 portion of the MCA, 75 mg of clopidogrel was added. Because the ischemic attack occurred again and because single photon emission computed tomography showed decreased cerebral blood flow, OA-MCA bypass was performed (Figure 1). Postoperatively, the ischemic attack stopped, and antiplatelet therapy was reduced to 100 mg aspirin only. MRA performed 1 year later revealed patent OA (Figure 1H).
DISCUSSION
STA-MCA bypass is a basic procedure for vascular neurosurgeons that is used to treat a variety of diseases such as cerebral ischemia, complex aneuVideo available at rysms,3 and tumors.4 However, there are cases in WORLDNEUROSURGERY.org which the STA is hypoplastic or aplastic, and in those cases, a graft bypass is sometimes adapted using the radial artery, saphenous vein,5 or OA,6 among others.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2017.08.126
TECHNICAL NOTE
Figure 1. Serial intraoperative pictures of case 1. (A) The subgaleal segment of the occipital artery (OA) lies in the loose areolar tissue (illustration, arrowheads). To harvest enough length, the OA was dissected to the point where it entered the subcutaneous fat layer (arrow). (B) Usually, a branch with a similar size as the main trunk exists, and it was also harvested in this case (arrowheads). (C) A gutter was made for the OA to reach the recipient directly and avoid occlusion by compression of the skin. (D) The harvested OA could reach the periphery of the angular artery (arrow) easily. (E) After double-barrel anastomosis. (F) Indocyanine green video angiography opacified the OA and recipient middle cerebral artery. (G) Preoperative computed tomography angiography. The superficial temporal artery (arrowheads) was used for revascularization of the anterior cerebral artery area. (H) Magnetic resonance angiography (MRA) performed 1 year after the operation revealed patency of the OA (double arrow).
WORLD NEUROSURGERY 108: 201-205, DECEMBER 2017
www.WORLDNEUROSURGERY.org
203
TECHNICAL NOTE
Figure 2. (A) Preoperative digital subtraction angiography (DSA) of case 1 shows occlusion of the superficial temporal artery (STA) (arrowheads) and an anastomosis between the occipital artery (OA) and the periphery of the parietal branch of the STA (arrow). (B) Postoperative DSA shows an OAemiddle cerebral artery (MCA) double-barrel anastomosis. (C) Magnetic resonance angiography (MRA) performed 3 years after the operation. The OA (arrowheads) shows patency.
In graft bypass, however, the procedure becomes more complex because it requires harvesting the graft and performing an additional anastomosis between the initial donor and the graft vessel, which can increase the risk of occlusion of the bypass. In addition, when large vessels are used, especially in ischemic cases, hyperperfusion could become a problem.7 Hence, in the cases presented here, we planned direct OA-MCA bypass. Most likely because it is more cumbersome to harvest the OA than the STA, only 1 case report documenting direct OA-MCA bypass was found in the literature,8 and the case showed that an appropriate OA-STA bypass can maintain patency during long-term follow-up.9 In harvesting the OA as the donor, understanding of the anatomy is essential to reduce trouble in harvesting.10,11 The ascending segment of the OA can be harvested 5e7 cm above the superior nuchal line, and the length of the OA to be harvested depends on how well the OA is developed. Presumably because of STA absence or an insufficient cutaneous blood supply from the STA, the OA was developed well in our 4 cases. To make the anastomosis procedure less difficult and ensure the patency of the bypass, preparation of the donor artery is as important as STA-MCA bypass. First, the OA should be harvested under a microscope to the point where the main trunk enters the subcutaneous fat from the loose areolar tissue layer. With slight magnification, small branches arising from the OA can be identified, coagulated, and cut meticulously, which reduces
REFERENCES 1. JET Study Group. Japanese EC-IC Bypass Trial (JET Study): the second interim analysis. Surg Cereb Stroke. 2002;30:434-437.
204
www.SCIENCEDIRECT.com
mechanical vasospasm and prevents dissection or damage caused by the extraction of such branches. Although care should be taken not to distort the OA, a longer donor artery makes it easier to turn the donor side to ascertain the correctness of each of the stitches of the anastomosis. Second, a gutter should be made to avoid compression of the OA when the patient is lying supine. Third, because the OA has few branches between the origin and the suboccipital segment, the lumen should be well heparinized to prevent clot formation during the anastomosis procedure. Which branch of the MCA is appropriate as the recipient is controversial. Considering the cumbersomeness of preparation of the OA, it might be better to choose the periphery of the posterior temporal artery, as in the case previously reported and in our second case, given that the length of the OA needed to reach the recipient is shorter than the distance to the angular artery. However, in cases of ischemia in the frontal and parietal lobes, as in our cases, it would be better to choose the periphery of the superior trunk as the recipient; the OA can reach it if it is well developed and dissected to the superior temporal line.
CONCLUSIONS The OA can be used as a donor for revascularization of the MCA area when the STA is not available. Meticulous harvesting of the OA is important to make the anastomosis feasible.
2. Kidani N, Kimura T, Ichikawa Y, Usuki K, Morita A. Steroids and immunosuppressant agents do not affect indirect revascularization in quasi-moyamoya disease associated with pure red cell aplasia: a case report. NMC Case Rep J. 2015;2: 12-15.
3. Lawton MT, Hamilton MG, Morcos JJ, Spetzler RF. Revascularization and aneurysm surgery: current techniques, indications, and outcome. Neurosurgery. 1996;38:83-92 [discussion: 92-94].
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2017.08.126
TECHNICAL NOTE
4. Moritake K, Handa H, Yamashita J, et al. STA-MCA anastomosis in patients with skull base tumours involving the internal carotid arteryehaemodynamic assessment by ultrasonic Doppler flowmeter. Acta Neurochir (Wien). 1984;72:95-110.
5. Bisson EF, Visioni AJ, Tranmer B, Horgan MA. External carotid artery to middle cerebral artery bypass with the saphenous vein graft. Neurosurgery. 2008;62(6 suppl 3):1419-1424.
6. Takeuchi S, Koike T, Tanaka R. Anastomosis of the superficial temporal artery to the middle cerebral artery with the interposed occipital artery graft in moyamoya disease: case report. Surg Neurol. 1997;48:615-619.
7. Stiver SI, Ogilvy CS. Acute hyperperfusion syndrome complicating EC-IC bypass. J Neurol Neurosurg Psychiatry. 2002;73:88-89.
bypass: microsurgical anatomy. Neurosurg Focus. 2008;24:E9.
8. Spetzler R, Chater N. Occipital arteryemiddle cerebral artery anastomosis for cerebral artery occlusive disease. Surg Neurol. 1974;2:235-238.
The content of this article was presented as a poster at 15th European Congress of Neurosurgery (EANS) 2014, Prague, Czech Republic. Received 21 June 2017; accepted 18 August 2017
9. Stoll A, Chater N. Long-term patency of occipital artery-middle cerebral artery bypass demonstrated by angiography. Surg Neurol. 1981;16:41-43.
Citation: World Neurosurg. (2017) 108:201-205. http://dx.doi.org/10.1016/j.wneu.2017.08.126 Journal homepage: www.WORLDNEUROSURGERY.org
10. Alvernia JE, Fraser K, Lanzino G. The occipital artery: a microanatomical study. Neurosurgery. 2006;58(1 suppl):ONS114-ONS122 [discussion: ONS114-ONS122].
Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2017 Elsevier Inc. All rights reserved.
11. Ates O, Ahmed AS, Niemann D, Baskaya MK. The occipital artery for posterior circulation
WORLD NEUROSURGERY 108: 201-205, DECEMBER 2017
www.WORLDNEUROSURGERY.org
205
Occipital Artery to Middle Cerebral Artery Bypass: Operative Nuances Toshikazu Kimura1 and Akio Morita2
BACKGROUND: Superficial temporal artery (STA)emiddle cerebral artery (MCA) anastomosis is a common procedure for vascular neurosurgeons, and it is used in a variety of diseases. However, there are cases in which the STA is absent or is too hypoplastic to be used as a donor for revascularization. Occipital artery (OA)eMCA bypass may be a treatment option in these cases.
-
METHODS: We encountered 4 cases of symptomatic cerebral ischemia in which the STA was absent or unavailable. These cases were treated by revascularization from the OA to the periphery of the MCA.
-
RESULTS: By meticulous dissection of the OA to the level of the superior temporal line, the OA could reach the periphery of the angular artery and be anastomosed to it in the usual fashion. The patency of the donor artery was confirmed by magnetic resonance angiography soon after the operation and 3 years later.
-
CONCLUSIONS: OA-MCA bypass may be a surgical option for cerebral revascularization when the STA is not available.
-
S
uperficial temporal artery (STA)emiddle cerebral artery (MCA) bypass is an established procedure used to treat a variety of diseases, such as cerebral ischemia, complex cerebral aneurysms, and neoplasms. However, in certain cases, the STA is absent or unavailable because of hypoplasia or a previous operation. In these cases, graft bypass is sometimes adapted using the radial artery, saphenous vein, occipital artery (OA), or other vessel, but graft bypass has several limitations, such as a need for complex procedures and the production of multiple surgical scars. In this article, we report use of the OA in
Key words Cerebral ischemia - EC-IC bypass - Moyamoya - OA-MCA bypass - Occipital artery -
Abbreviations and Acronyms DSA: Digital subtraction angiography MCA: Middle cerebral artery MRA: Magnetic resonance angiography OA: Occipital artery STA: Superficial temporal artery
WORLD NEUROSURGERY 108: 201-205, DECEMBER 2017
place of the STA for direct anastomosis and describe the technical nuances of this approach.
MATERIALS AND METHODS Between 2007 and 2015, 187 external-to-internal carotid artery bypasses were performed at our institution to treat moyamoya disease and hemodynamic ischemia because of atherosclerotic steno-occlusive disease of the major cerebral arteries. In ischemic steno-occlusive disease, the surgical indication was determined based on the criteria of the Japanese EC-IC Bypass Trial (JET study),1 assessing the cerebral blood flow using single-photon emission computed tomography with iodine123 N-isopropyl-iodoamphetamine accompanied by acetazolamide challenge when possible. Among the cases, OA-MCA bypass was performed in 4 cases (Table 1). One case involved ischemic moyamoya disease,2 and the other 3 involved atherosclerotic stenoocclusive disease. In the moyamoya case, the frontal branch of the STA had anastomosis with the anterior cerebral artery; hence, the parietal branch of the STA and OA was anastomosed to the M4 portion of the MCA. TECHNICAL NOTE During the operation, the patient was placed in the lateral position, with the head slightly rotated to the contralateral side, and the vertex was slightly elevated to reduce venous pressure. After confirming the course of the OA with Doppler sonography, a curved incision was made along the suboccipital and subgaleal segments of the OA. The OA was dissected from the galea under a microscope, from its periphery to the point where it pierces the splenius capitis muscle (Figure 1A). Retraction with a skin hook to open the incision slightly upward is useful to identify small branches of the OA because they exist in the same loose areolar tissue as the main trunk. Along the main trunk, one large branch can be identified in the subgaleal portion, which
From the 1Department of Neurosurgery, Japanese Red Cross Medical Center, Tokyo; and the 2 Department of Neurosurgery, Nippon Medical University, Tokyo, Japan To whom correspondence should be addressed: Toshikazu Kimura, M.D., Ph.D. [E-mail: [email protected]] Citation: World Neurosurg. (2017) 108:201-205. http://dx.doi.org/10.1016/j.wneu.2017.08.126 Supplementary digital content available online. Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2017 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
201
TECHNICAL NOTE
Table 1. Patient List Age (years)
Sex
Presentation
Preoperative Condition of STA
Single/Double
Site of First Anastomosis
Site of Second Anastomosis
Follow-Up Period (years)
1
54
M
Cognitive disturbance
Hypoplastic/retrograde via OA
Double
Angular
Post. temporal
5.4
2
30
F
Infarction (moyamoya)
Frontal br. fed cortex
STA parietal br. plus single OA
Posterior temporal
3
71
F
TIA
Already used
Double
Angular
Post. temporal
4.4
4
69
F
TIA
Cut in previous operation
Double
Angular
Post. temporal
3.1
Case
5.0
STA, superficial temporal artery; M, male; OA, occipital artery; F, female; Post. temporal, posterior temporal artery; br., branch; TIA, transient ischemic attack.
should be preserved for use as a conduit for rinsing inside the donor artery and for a second anastomosis (Figure 1B). To dissect the suboccipital portion of the OA, the sternocleidomastoid muscle was reflected anteriorly with the skin flap. The splenius capitis muscle was cut along the OA, and the upper part was also reflected anteriorly to make room for the guttering. The descending branches of the OA supplying the suboccipital muscles were dissected and cut after coagulation. Where the main trunk of the OA makes a hairpin curve, the connective tissue between the curve was dissected to stretch the OA during the anastomosis procedure. A concomitant vein was dissected from the OA to enhance the visibility and movability of the OA. By reflecting the longissimus capitis muscle inferiorly, the OA was exposed near the mastoid process. The incision was then extended anteriorly along the superior temporal line from the upper end of the vertical incision to perform the craniotomy. To prevent compression of the donor artery while the patient was lying supine, a gutter was made from the bottom of the craniotomy toward the proximal OA (Figure 1C). After manipulation of the bone, the OA was transected at the peripheral end, and its lumen was rinsed with heparin saline. Because the OA has few branches between the origin at the external carotid artery and the exposed suboccipital segment, heparin saline was injected to fill the proximal lumen, and the OA was occluded with an aneurysm clip to prevent clot formation. The length of the harvested OA was approximately 7 cm, and it was anastomosed to the periphery of the angular artery with intermittent sutures using 10-0 nylon (Figure 1D). Because the recipient artery was a peripheral artery, the diameter was smaller than the usual recipient M4 in STA-MCA bypass. Hence, the arteriotomy had to be a little longer than in the STAMCA bypass to ensure that the vessel walls met correctly. The other branch of the OA was anastomosed to the posterior temporal artery as well (Figures 1E and 1F and Video 1).
RESULTS The postoperative course was uneventful in all 4 cases. Magnetic resonance angiography (MRA) performed 3e5 years after the operation showed patency of the bypass in all 4 cases (Table 1).
202
www.SCIENCEDIRECT.com
Illustrative Cases Case 1. A 54-year-old man presented with dysarthria and confusion. He had a history of cerebral infarction in the right frontal lobe 9 years previously and had been on low-dose aspirin. Magnetic resonance imaging revealed a new infarction in the left basal ganglia and occlusion of the right internal carotid artery, which had already been noted. On digital subtraction angiography (DSA), there was also severe stenosis at the A1 segment of the left anterior cerebral artery. The right MCA area was perfused through a leptomeningeal anastomosis from a posterior cerebral artery. Single photon emission computed tomography showed decreased blood flow in the right parietal lobe. Acetazolamide challenge revealed a compromised vascular reserve in this area. Therefore, cerebral revascularization was recommended. The patient’s right STA was not palpable on physical examination. On DSA, the right OA had developed enough to supply the frontal area (Figure 2A); hence, direct OA-MCA bypass was performed. Postoperative DSA showed a patent bypass (Figure 2B), and the patient returned to his job 5 months after the operation. MRA performed 3 years later showed patency of the bypass (Figure 2C).
Case 3. A 71-year-old woman presented with a transient ischemic attack of motor aphasia and right hemiparesis. She had undergone an STAeanterior cerebral artery bypass for a minor stroke in the anterior cerebral artery region (Figure 1G) and had been taking 100 mg of aspirin daily. Because MRA showed severe stenosis at the M1 portion of the MCA, 75 mg of clopidogrel was added. Because the ischemic attack occurred again and because single photon emission computed tomography showed decreased cerebral blood flow, OA-MCA bypass was performed (Figure 1). Postoperatively, the ischemic attack stopped, and antiplatelet therapy was reduced to 100 mg aspirin only. MRA performed 1 year later revealed patent OA (Figure 1H).
DISCUSSION
STA-MCA bypass is a basic procedure for vascular neurosurgeons that is used to treat a variety of diseases such as cerebral ischemia, complex aneuVideo available at rysms,3 and tumors.4 However, there are cases in WORLDNEUROSURGERY.org which the STA is hypoplastic or aplastic, and in those cases, a graft bypass is sometimes adapted using the radial artery, saphenous vein,5 or OA,6 among others.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2017.08.126
TECHNICAL NOTE
Figure 1. Serial intraoperative pictures of case 1. (A) The subgaleal segment of the occipital artery (OA) lies in the loose areolar tissue (illustration, arrowheads). To harvest enough length, the OA was dissected to the point where it entered the subcutaneous fat layer (arrow). (B) Usually, a branch with a similar size as the main trunk exists, and it was also harvested in this case (arrowheads). (C) A gutter was made for the OA to reach the recipient directly and avoid occlusion by compression of the skin. (D) The harvested OA could reach the periphery of the angular artery (arrow) easily. (E) After double-barrel anastomosis. (F) Indocyanine green video angiography opacified the OA and recipient middle cerebral artery. (G) Preoperative computed tomography angiography. The superficial temporal artery (arrowheads) was used for revascularization of the anterior cerebral artery area. (H) Magnetic resonance angiography (MRA) performed 1 year after the operation revealed patency of the OA (double arrow).
WORLD NEUROSURGERY 108: 201-205, DECEMBER 2017
www.WORLDNEUROSURGERY.org
203
TECHNICAL NOTE
Figure 2. (A) Preoperative digital subtraction angiography (DSA) of case 1 shows occlusion of the superficial temporal artery (STA) (arrowheads) and an anastomosis between the occipital artery (OA) and the periphery of the parietal branch of the STA (arrow). (B) Postoperative DSA shows an OAemiddle cerebral artery (MCA) double-barrel anastomosis. (C) Magnetic resonance angiography (MRA) performed 3 years after the operation. The OA (arrowheads) shows patency.
In graft bypass, however, the procedure becomes more complex because it requires harvesting the graft and performing an additional anastomosis between the initial donor and the graft vessel, which can increase the risk of occlusion of the bypass. In addition, when large vessels are used, especially in ischemic cases, hyperperfusion could become a problem.7 Hence, in the cases presented here, we planned direct OA-MCA bypass. Most likely because it is more cumbersome to harvest the OA than the STA, only 1 case report documenting direct OA-MCA bypass was found in the literature,8 and the case showed that an appropriate OA-STA bypass can maintain patency during long-term follow-up.9 In harvesting the OA as the donor, understanding of the anatomy is essential to reduce trouble in harvesting.10,11 The ascending segment of the OA can be harvested 5e7 cm above the superior nuchal line, and the length of the OA to be harvested depends on how well the OA is developed. Presumably because of STA absence or an insufficient cutaneous blood supply from the STA, the OA was developed well in our 4 cases. To make the anastomosis procedure less difficult and ensure the patency of the bypass, preparation of the donor artery is as important as STA-MCA bypass. First, the OA should be harvested under a microscope to the point where the main trunk enters the subcutaneous fat from the loose areolar tissue layer. With slight magnification, small branches arising from the OA can be identified, coagulated, and cut meticulously, which reduces
REFERENCES 1. JET Study Group. Japanese EC-IC Bypass Trial (JET Study): the second interim analysis. Surg Cereb Stroke. 2002;30:434-437.
204
www.SCIENCEDIRECT.com
mechanical vasospasm and prevents dissection or damage caused by the extraction of such branches. Although care should be taken not to distort the OA, a longer donor artery makes it easier to turn the donor side to ascertain the correctness of each of the stitches of the anastomosis. Second, a gutter should be made to avoid compression of the OA when the patient is lying supine. Third, because the OA has few branches between the origin and the suboccipital segment, the lumen should be well heparinized to prevent clot formation during the anastomosis procedure. Which branch of the MCA is appropriate as the recipient is controversial. Considering the cumbersomeness of preparation of the OA, it might be better to choose the periphery of the posterior temporal artery, as in the case previously reported and in our second case, given that the length of the OA needed to reach the recipient is shorter than the distance to the angular artery. However, in cases of ischemia in the frontal and parietal lobes, as in our cases, it would be better to choose the periphery of the superior trunk as the recipient; the OA can reach it if it is well developed and dissected to the superior temporal line.
CONCLUSIONS The OA can be used as a donor for revascularization of the MCA area when the STA is not available. Meticulous harvesting of the OA is important to make the anastomosis feasible.
2. Kidani N, Kimura T, Ichikawa Y, Usuki K, Morita A. Steroids and immunosuppressant agents do not affect indirect revascularization in quasi-moyamoya disease associated with pure red cell aplasia: a case report. NMC Case Rep J. 2015;2: 12-15.
3. Lawton MT, Hamilton MG, Morcos JJ, Spetzler RF. Revascularization and aneurysm surgery: current techniques, indications, and outcome. Neurosurgery. 1996;38:83-92 [discussion: 92-94].
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2017.08.126
TECHNICAL NOTE
4. Moritake K, Handa H, Yamashita J, et al. STA-MCA anastomosis in patients with skull base tumours involving the internal carotid arteryehaemodynamic assessment by ultrasonic Doppler flowmeter. Acta Neurochir (Wien). 1984;72:95-110.
5. Bisson EF, Visioni AJ, Tranmer B, Horgan MA. External carotid artery to middle cerebral artery bypass with the saphenous vein graft. Neurosurgery. 2008;62(6 suppl 3):1419-1424.
6. Takeuchi S, Koike T, Tanaka R. Anastomosis of the superficial temporal artery to the middle cerebral artery with the interposed occipital artery graft in moyamoya disease: case report. Surg Neurol. 1997;48:615-619.
7. Stiver SI, Ogilvy CS. Acute hyperperfusion syndrome complicating EC-IC bypass. J Neurol Neurosurg Psychiatry. 2002;73:88-89.
bypass: microsurgical anatomy. Neurosurg Focus. 2008;24:E9.
8. Spetzler R, Chater N. Occipital arteryemiddle cerebral artery anastomosis for cerebral artery occlusive disease. Surg Neurol. 1974;2:235-238.
The content of this article was presented as a poster at 15th European Congress of Neurosurgery (EANS) 2014, Prague, Czech Republic. Received 21 June 2017; accepted 18 August 2017
9. Stoll A, Chater N. Long-term patency of occipital artery-middle cerebral artery bypass demonstrated by angiography. Surg Neurol. 1981;16:41-43.
Citation: World Neurosurg. (2017) 108:201-205. http://dx.doi.org/10.1016/j.wneu.2017.08.126 Journal homepage: www.WORLDNEUROSURGERY.org
10. Alvernia JE, Fraser K, Lanzino G. The occipital artery: a microanatomical study. Neurosurgery. 2006;58(1 suppl):ONS114-ONS122 [discussion: ONS114-ONS122].
Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2017 Elsevier Inc. All rights reserved.
11. Ates O, Ahmed AS, Niemann D, Baskaya MK. The occipital artery for posterior circulation
WORLD NEUROSURGERY 108: 201-205, DECEMBER 2017
www.WORLDNEUROSURGERY.org
205