:Acta Ndurochirurgica
Acta Neurochir (Wien) (1991) 112:13-18
9 Springer-Verlag 1991 Printed in Austria
Treatment of Proximal Vertebral Artery Stenosis Vertebral to Subclavian Transposition A. Ogawa, T. YosMmoto, and Y. Sakurai 1 Division of Neurosurgery, Institute of Brain Diseases, Tohoku University, School of Medicine, Sendal, and 1Department of Neurosurgery, Stroke Center, Sendai National Hospital, Sendai, Japan
Summary
Materials (Table 1)
For vascular reconstruction ill cases of atherosclerotic stenosis at the origin of the vertebral artery, we use vertebral to subclavian artery transposition. We discuss the advantages and effectiveness of such treatment based on a study of 32 cases. We have experienced neither surgical mortality nor morbidity and the outcome at the time of discharge has been favourable. Follow-up revealed no deaths, however, three cases exhibited symptoms of cerebral ischaemia. One had a supratentorial completed stroke, and the other two hat TIA or RIND, but without any notable lesion in the angiograms. There were no cases of cerebral infarction of the posterior fossa. We believe that this method should be the first choice for treatment of cases udthout lesions of the subclavian artery for the following reasons: serious operative complications have not been encountered, surgical invasion is minimal, temporary occlusion of the common carotid artery is unnecessary, the operation can be done by occluding only the vertebral artery, and unlike various bypass operations, anastomosis is required at only one location and is consequently technically uncomplicated. Following anastomosis the cerebral blood pathway is physiological.
As a rule, we perform vertebral to subclavian transposition in cases with symptoms of cerebral ischaemia indicative of TIA, RIND or minor completed stroke of the vertebrobasilar arterial system, when certain angiographic findings, described below, are also obtained. In all cases four-vessel angiography indicated stenosis at the origin of the vertebral artery. Surgical treatment was decided upon (i) when the contralateraI vertebral artery was occluded or hypoplastic or it ended at the posterior inferior cerebellar artery, and the radius of the origin of the vertebral artery was reduced up to 50% or (ii) when both vertebral arteries were visible, but the stenosis of the vertebral artery on the dominant side was greater than 70%. A total of 32 cases (22 male, 10 female), mean age 63 (44-73 years) were treated with vertebral to subclavian transposition. For three cases with compression of the vertebral artery due to a spur between C4-5 and/or C5-6, removal of the C5 and/or C6 transverse process and opening of the transverse foramen (transverse foraminectomy) was done at the same time. Postoperative angiograms were obtained in all cases and the patency of the transposition was observed. Surgical complications and postoperative conditions seen at discharge as well as any recurrence of ischaemic symptoms between the time of discharge and long-term follow-up were also studied. On discharge from the hospital, the condition of each patient was determined and they were classified into one of the following five categories; excellent: normal, without neurological deficits, good: mild neurological deficits, but able to return to normal social life, fair: normal social life not possible, but unassisted domestic life possible, poor: assistance required in domestic life, and dead.
Keywords: Cerebral ischaemia; vertebral artery reconstruction; vertebral to subclavian transposition; vertebrobasilar insufficiency.
Introduction Vertebral to carotid transposition, in which anastomosis of the vertebral artery to the common carotid artery is done, has become the treatment of choice for vascular reconstruction in cases of arteriosclerotic stenosis at the origin of the vertebral artery 13-17'24, 35. For lesions at this site, however, we use vertebral to subclavian transposititon, in which anastomosis of the vertebral artery to the subclavian artery is done 28' 29. In the present report, we discuss our surgical technique and the advantages and effectiveness of this treatment in the light of a study of 32 clinical cases.
Surgical Method (Fig. 1) A supraclavicular approach is used. The sternal head of the sternocleidomastoid muscle is ligated at the tendon of the sternum, cut and turned back there. The approach is made from the triangular region formed by the sternocleidomastoid muscle laterally, the sternothyroid and sternohyoid muscles medially, and the clavicle. The subclavian artery, vertebral artery, internal thoracic artery, thyreocervical trunk and costocervical trunk were dissected completely.
TIA
RIND
TIA
RIND, mCST
TIA, raCST
TIA
TIA
T1A
25. 69 M
26.73 M
27.60 M
28.70 M
29, 66 M
30.62 M
31.67 M
32. 67 M
kinking elongation
95% sten,
70% sten.
95% stere
80% stem
80% sten.
occlusion
90% sten.
90% sten.
kinking
50% stem
coiling
(It VA kink by C5-6 spur)
70% sten.
70% sten.
90% sten.
70% sten.
occlusion
80% sten.
90% sten.
60% sten.
elongation
(It VA kink by Cs~ spur)
80% sten.
kinking
70% sten.
elongation
80% sten.
70% sten.
95% sten.
50% sten.
60% sten.
70% sten.
70% sten.
60% sten,
it VA
Angiographic findings
elongation
other
hypoplasia
occlusion
hypoplasia
undominant
occlusion
hypoplasia
90% sten.
70% sten
80% sten.
hypoplasia
8g% sten.
30% sten.
occlusion
undominant
30% stem
50% sten. 90% sten.
hypoplasia
hypoplasia
rt IC sten.
rt IC occl,
It IC occl.
rt IC occl.
(rt VA kink by C~_6spur)
kinking,
30% sten.
90% sten.
30% sten.
hypop~asia
30% sten.
70% sten.
30% sten.
30% sten.
occlusion
30% sten.
60% sten.
hypoplasia
rt VA
(-)
(-)
(- )
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
brachial nerve palsy
(-)
(-)
(-)
(-)
(-)
(-)
(-)
It.
It.
It,
It.
It.
lt.
ft.
It.
It.
It.
it.
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
with transverse foraminectomy
It.
It.
It.
lt.
rt.
It.
It.
It.
with transverse foraminectomy
It.
with transverse foraminectomy
It,
rt.
It.
it.
It.
rt.
It.
It.
It.
It.
It.
(-)
complications
It.
Postoperative
Operation side
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
patency
Angiographic
Ex
Ex
Ex
G
Ex
Ex
Ex
Ex
Ex
Ex
Ex
G
Ex
Ex
Ex
G
Ex
G
Ex
Ex
Ex
Ex
Ex
Ex
Ex
Ex
Ex
Ex
Ex
Ex
Ex
Ex
on discharge
Outcome
Ex (Sin)
Ex (ly)
Ex (ly)
G (lylm)
Ex (ly3m)
Ex (ly5m)
Ex (lyl0m)
Ex (lyl0m)
F (lyl lm)
Ex (2y2m)
Ex (2y7m)
Ex (2y9m)
Ex (2yl0m)
Ex (2yl tm)
Ex (2yl lm)
G (3ylm)
Ex (3ylm)
G (3y4m)
Ex (3y5m)
Ex (3y5m)
Ex (3y7m)
Ex (3y7m)
Ex (3y9m)
Ex (4y)
Ex (4y)
Ex (4ylm)
Ex (4yTm)
Ex (4y7m)
Ex (5yl m)
Ex (5y)
Ex (6y)
Ex (6y2m)
at follow-up
Outcome
T I A : t r a n s i e n t i s c h a e m i c a t t a c k , R I N D : reversible i s c h a e m i c n e u r o l o g i c a l deficit. m C S T : m i n o r c o m p l e t e d s t r o k e , VA: v e r t e b r a l a r t e r y , sten.: stenosis.
RIND
24.61 M
TIA
19.65 F
TIA
TIA
18.72 M
TIA
mCST
17.58 M
23.55 M
TIA
16.69 M
22. 63 M
mCST
15.61 M
RIND
TIA
14. 68 F
TIA
TIA
13.52 M
21.74 F
TIA
12. 72 F
20. 59 M
mCST
11.55 F
TIA, mCST
7. 65 F
RIND
TIA, RIND
6.44 M
10.65 M
TIA
5. 56 F
TIA
TIA
4. 58 M
TIA
TIA
3.72 M
9.53 F
TIA
8. 62 M
TIA
I. 46 F
Symptom
Clinical Summary of 32 Pat&nts Undergoing Vertebral to Subclavian Transposition
2. 60 M
Case
T a b l e 1.
(+) CST by It I~ stenosis (ly6m)
lesion
(+) TIA (Sm and ly) no angiographic
(+) Rind (2y) no angiographic lesion
during follow-up
Ischaemic symptoms
>
p~
r-.
9
.~
15
A. Ogawa et al.: Treatment of Proximal Vertebra1 Artery Stenosis
Table 2. Summary of Surgical Complications, Vascular Patency and Follow-up Results
Surgical complications Horner's syndrome transient brachial nerve palsy Surgical mortality Angiographic patency Ischaemic symptoms during follow-up
Fig, 1. Surgical view and completion of vertebral to subclavian transposition
Dissection of the vertebral artery peripherally proceeds as far as the transverse process of the sixth cervical vertebra. Immediately prior to temporary vascular occlusion, 500 ml mannitol, 500 mg vitamin E and 500 mg of phenytoin (the Sendal cocktail) are adminstered by intravenous drip to prevent ischaemic brain damage27, 36~0,42, 45, 46 Aneurysm clips are used for occluding each
frequently 1/32
3.1%
0/32
0%
32/32
100%
3/32
9.4%
branching arteries, but the subclavian artery is occluded with vascular clamps. To prevent any disturbance of the operative field, we ihave designed damps with a 90 ~ bend for use in this operation. In anticipation of accidental bleeding during the operation, we also, put a vessel tape around the proximal portion of the subclavian artery. Ligation and/or clipping of the vertebral artery is done as far proximally as possible. To cut the subclavian artery, a vascular punch with a similar diameter of the vertebral artery is used. The vertebral artery is cut on a slight angle, and anastomosis to the subclavian artery using 7-0 nylon thread is done under a surgical microscope. After placing two stay sutures on the deepest (contralateral) side of the wall of the cut artery running suturing of each I/3 of the entire circumference is carried out. Then a third stay suture is put in place and the remaining suturing is easy and the vascular lumen is rinsed with heparin-added pyhsiological saline. When all air in the lumen has been replaced, temporary occlusion is released.
Fig. 2. Pre- and postoperative angiograms. Left: Preoperative angiogram, demonstrating marked stenosis at the origin of the vertebral artery. Right: Postoperative angiogram, showing completion of vertebral to subclavian transposition and disappearance of stenosis
16
Results (Tables 1 and 2) In postoperative angiograms, the anastomosis was found to be patent and satisfactory vascular dilatation was obtained in all cases (Fig. 2). The condition of the patients on discharge was excellent in 28 cases and good in 4 cases. There were no fair or poor outcomes and no deaths. Horner's syndrome was seen postoperatively in almost all cases, but in most the symptoms were transient. In one case undergoing removal of the transverse process, there was transient brachial nerve palsy, but no other new neurological symptoms were found. Follow-up study was possible in all cases between 5 and 74 months postoperatively (mean follow-up of 37 months). The condition of the patients at followup was excellent in 28 cases, good in 3 and fair in 1, without any deaths during the follow-up period. Three patients had experienced symptoms of cerebral ischaemia during the follow-up period. Two of these patients had no notable lesion on the angiograms. The symptoms were TIAs or RIND and no further ischaemic events were experienced. In one case, 18 months after the vertebral to subclavian transposition, severe stenosis of the left internal carotid artery without an obvious vascular lesion was seen and there was supratentorial infarction. It was diagnosed as a completed stroke with fight hemiparesis and aphasia. Discussion
Vascular reconstruction for atherosclerotic stenosis at the origin of the vertebral artery was first reported by Crawford et al. in 19581~ and by Cate et al. in 19596 using endarterctomy. Subsequently, many reports appeared, and endarterectomy for vascular reconstruction in this region became the current treatment 8' 9, 12, 19, 20, 22, 23~ 25, 26, 33, 41, 44. There have been reports on endarterectomy after arteriotomy of the subclavian artery or the vertebral artery. Since, in comparison with the subclavian or the carotid arteries, the arterial wall of the vertebral artery is much thinner and weaker when undertaking endarterectomy, there have been relatively numerous reports of endarterectomy following arteriotomy of the subclavian artery 41. However, when performing endarterectomy using a subclavian arteriotomy, especially for cases with an earlier branching vertebral artery, there are many cases in which endarterectomy using a supraclavicular approach is difficult and thoracotomy, sternotomy or clavicotomy is required. In view of the greater invasiveness of thoracotomy, sternotomy or clavicotomy, transposition is technically an easier operation, postoperative patency
A. Ogawa et al.: Treatment of Proximal Vertebral Artery Stenosis
of the arteries is good, and this technique has recently become dominant. On the other hand, there have been many reports on anastomosis of vessels in this region. In 1959, DeBakey et al.ll reported a bypass operation with anastomosis between the subclavian and the vertebral arteries using a venous graft. Thereafter, similar bypass techniques were devised, including side-to-side anastomosis of the common carotid and vertebral arteries 15, a bypass using a graft between the common carotid and vertebral arteries 4, side-to-side anastomosis of the subclavian and vertebral arteries 32' 43, external carotid to vertebral artery anastomosis 7' 21, 3o, anastomosis of the thyrocervical trunk and the vertebral artery 8' 31 and internal carotid to vertebral artery anastomosis I. In 1976, Comier et al. 8' 9 described four cases of vertebral to carotid transposition, in which the common carotid artery was anastomosed to the vertebral artery among 172 cases of vascular reconstruction for vascular lesions of the vertebral artery, subclavian artery, and the inominate artery. In 1972, Edwards e t a L reported sideto-side anastomosis of the vertebral artery and common carotid artery and found postoperative bleeding due to stretching of the vertebral artery. They later reported that vertebral to carotid transposition should be performed 14' 15. Not only vascular surgeons, Diaz e t a l J 3 and Spetzlar et al. 35 and others have since reported a relatively large series from neurosurgeons, and vertebral to carotid transposition has become the predominant vascular reconstruction for lesions at the origin of the vertebral artery. On the other hand, one main reason this surgical procedure has become predominant is that it progressed from the surgical reconstruction of the vertebral artery accompanied with the vascular lesions of the large arteries, such as the aorta, the inominate artery and the subclavian artery. When there is no stenosis of the subclavian artery, its use as the donor artery appears to present no problems. One of the advantages of vertebral to subclavian transposition is the simplicity of the approach and the small amount of invasiveness which it entails. We have not had any cases, including those with early branching of the vertebral artery from the subclavian artery, in which thoracotomy, sternotomy or clavicotomy has been required. All cases have been operated upon using the supraclavicular approach. Moreover, since elongation of the subclavian artery due to arteriosclerosis was found in many of these patients, technical difficulties in the anastomosis due to shortness of the vertebral artery were not experienced. Another advantage of this method is that temporary occlusion of the c o m -
A. Ogawa et aL: Treatment of Proximal Vertebral Artery Stenosis
17
m o n carotid artery in addition to occlusion of the vertebral artery is not required, as it is in vertebral to carotid transposition. Therefore, it is possible to perform the surgery with a minimum of vascular occlusion. Moreover, in comparison with a variety of bypass techniques, transposition involves only one anastomosis and the technique is relatively simple. Provided that there is no stenosis of the subclavian artery, the blood pathway after anastomosis is physiological. Therefore, we have concluded that, in cases where a stenotic vascular lesion of the subclavian artery is not found, vertebral to subclavian anastomosis is the first choice for stenosis at the origins of the vertebral artery. In the present series there were no cases of ischaemic complications due to temporary occlusion during surgery. Prior to temporary occlusion, we administer 500 ml mannitol, 500 mg Vitamin E and 500 mg phenytoin (the Sendai cocktail) and use cross clamping. M a n y previous studies on the brain protective effects of the Sendai cocktail have been reported 27' 36-4o 42, 45, 46. The duration of the cross clamping required for this operation is of the order of 30 minutes. We believe that temporary occlusion of the vertebral artery, under the administration of brain protective substances immediately prior to occlusion, is, in fact, safe. Although shunt techniques have also been reported for vascular reconstruction in this region 31" 34, they are complex, require incision of the vertebral artery, which is in any case thin and weak, and seem not to be better alternatives in so far as they entail greater risks than the present technique. As for the surgical complications occurring in this series, the transient brachial nerve palsy was due to the removal of the transverse process and there were no notable complications other than Horner's syndrome due to the vertebral to subclavian transposition itself. Since dissection of the origin of the vertebral artery entails perivascular sympathectomy in this region, the appearance of H o m e r ' s syndrome is thought to be inevitable. There were, however, almost no postoperative complaints concerning this syndrome, and it is not considered to be a significant clinical problem. There have also been reports of lymphorrhea and recurrent nerve palsy as a complication of this operation, but we have not found this in our present series. We conclude, therefore, that in vertebral to subclavian transposition, since there is no need ~0 dissect the c o m m o n carotid artery and the approach is made from a more lateral direction, this technique is safe also from the perspective of complications. Serious sequelae do not arise following vertebral to subclavian transposition. We have not experienced
morbidity or mortality in our series, and we find the operation to be relatively easy. In our postoperative follow-up study, there have been no cases of recurrence of ischaemia in the posterior fossa. Cerebral ischaemia of the vertebro-basilar system is not rare 5' 47, and the importance of the involvement of extracranial vertebral artery lesions has previously been noted 18. For these reasons, we believe that the vertebral to subclavian transposition for lesions at the origin of the vertebral artery is an effective therapeutic technique. It is, however, true that we do not yet have a sufficient understanding of the natural course of ischaemia of the vertebral artery system and questions concerning indications for surgical treatment remain unanswered. Further study of these problems is thus much needed.
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