Giant intracranial aneurysm surgery: The role of microvascular reconstruction

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Giant Intracranial Aneurysm Surgery : The Role of Microvascular Reconstruction James I . Ausman, M .D., Ph.D., Fernando G . Diaz, M.D., Ph.D., Balaji Sadasivan, F .R.C .S., Marco Gonzeles-Portillo, Jr., M.D ., Ghaus M . Malik, M.D ., and Chandrashekhar E . Deopujari, M .S ., M.Ch. Henry Ford Neurosurgical Institute, Henry Ford Hospital Division, Department of Neurological Surgery, Detroit, Michigan

Austrian J1, Dia¢ FG, Sadasivan B, Gonzales-Portillo M, Malik GM, Deopujari CE . Giant intracranial aneurysm surgery : the role of microvascular reconstruction . Surg Neurol 1990 ;34 : 8-15 .

The surgical management of 62 anterior circulation giant intracranial aneurysms is presented . Women were affected three times as frequently as men . Thirty-two patients presented with local mass effect, which was the most common mode of presentation, while 26 patients had subarachnoid hemorrhage. Three patients presented with transient ischemic attacks and three patients presented with seizures. In 16 cases the giant intracranial aneurysm involved the cavernous sinus and indirect surgery was performed . Ten patients were treated with extracranial-intracranial bypass and gradual occlusion of the proximal internal carotid artery . Six patients were treated with extracranial-intracranial bypass and trapping of the aneurysm (sudden occlusion of internal carotid artery). Sudden occlusion was poorly tolerated, and 50% of the patients developed ischemic complications. In 46 cases of giant intracranial aneurysm without involvement of the cavernous sinus, direct surgery was undertaken . In 31 patients the aneurysm could be clipped without compromise to the surrounding vessels . In 15 patients there was compromise of surrounding vessels or the aneurysm sac was excised and so microvascular reconstruction was needed . Local intracranial reconstruction was preferred whenever feasible. The results of patients who needed reconstruction were similar to those who did not need reconstruction . Overall, 84% of patients had an excellent or good outcome after surgery . The mortality was 5% . KEY WORDS : Giant aneurysm ; Extracranial-intracranial by-

pass ; Microvascular reconstruction ; Subarachnoid hemorrhage ; Surgical treatment ; Carotid artery

Address reprint requests to:James 1. Ausman, M .D., Ph .D ., Department of Neurosurgery, Henry Ford Neurosurgical Institute, 2799 West Grand Boulevard, Detroit, Michigan 48202 . Received December 21, 1989 ; accepted February 13, L990 .

0 1990 by Elsevier Science Publishing Co ., Inc.

Introduction Giant intracranial aneurysms (GlAs) are aneurysms whose outer diameter is greater than 2 .5 cm 115] . The neck of the aneurysm is usually large and may be fragile, due to a hypoplastic wall, or rigid, because of an atheromatous plaque or thrombi [22] . Frequently, the sac is adherent to surrounding vessels and neural structures . The branches of the parent vessel often arise directly from the neck or are incorporated in the aneurysm wall [6] . A variety of surgical techniques are therefore necessary to treat these aneurysms without compromising the adjacent vessels or neural structures . In this report, we present our experience with the surgical management of 62 anterior circulation GIAs . Thirty-one of the patients required microvascular reconstruction . There were two types of microreconstructive procedures performed : the extracranial-intracranial (EC-IC) bypass and intracranial reconstructive procedures such as aneursymorrhaphy, anterior cerebral artery (ACA), and middle cerebral artery (MCA) end-to-end or end-to-side anastomosis, and MCA branch transposition .

Clinical Material Between January 1979 and December 1987, 62 cases of anterior circulation GIAs were surgically treated at Henry Ford Hospital . Table 1 shows the age and sex

Table 1 . Age and Sex Distribution of Patients Age (years) 21-30 31-40 41-50 51-60 61-70 71-80 81-90

Totals

Male

Female

Total

1 1 4 5 2 2 0 15 (24%)

1 3 13 15 10 4 1 47 (76%)

2 4 17 20 12 6 1 62

0090-3019/90/$3 .50



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Table 3 . Cases Requiring Decompression by Clot Evacuation from Within the Aneurysm or Aneurysm Excision and Vascular Reconstruction During Direct Surgery

ophthslc artery Anterlor cerebral artery

Location

Addle cerebral artery

of aneurysm

of

Total no. aneurysms

No. requiring decompression

1(8%) Ophthalmic 13 3 Posterior communicating 0(0%) Carotid bifurcation 3 2(670/,) MCA 22 13(59%) AComA 5 4(80%) 46 20(43%) Total Abbreviations : AComA, anterior communicating artery ; MCA, middle cerebral artery .

Posterior eonnaadeat" artery

Figure 1 . Location of giant intrananial aneurysm .

distribution . There was a predominance of female patients (76%) . The majority of patients presented in the fourth and fifth decade, with the youngest patient aged 23 years and the oldest 82 years . The site and location of the aneurysms are shown in Figure 1 . The clinical presentation that led to the diagnosis is shown in Table 2 . Local mass effect was responsible for the initial symptoms in 32 (51%) patients . Subarachnoid hemorrhage occurred in 24 patients (39%) . Transient ischemic attacks presumably caused by emboli from the aneurysm occurred in three patients (5%) . The GIA was discovered during the investigation of seizures in three patients (5%) . Sixteen patients were treated with proximal ligation of the carotid artery and an EC-IC bypass (indirect surgery) . In 15 cases the GIA was located at the cavernous carotid artery and in one case it was located at the ophthalmic artery . This single case of ophthalmic GIA treated with proximal ligation and EC-IC bypass had been explored at another institution and the GIA was thought to be unclippable because of cavernous sinus involvement . In 10 patients, a superficial temporal artery (STA)-to-MCA bypass (nine cases) or an external carotid artery-to-MCA vein graft anastomosis (one case) was performed . At the same time a Selverstone clamp was placed on the internal carotid artery (ICA) . After the patency of the bypass was checked by angiography, the ICA was gradually occluded over 7-10 days . Transient

neurological deficits occurred in three cases, and so gradual occlusion was done under heparinization in seven cases . In six patients, a STA proximal MCA bypass was performed through a pterional craniotomy . The intracranial ICA and the cervical ICA were then ligated or clipped, resulting in trapping of the aneurysm with abrupt occlusion of the ICA . Forty-six patients were treated with direct surgery of the GIA . In 20 patients (43%), in addition to obliteration of the aneurysm, decompression by clot evacuation from within the aneurysm or aneurysm excision was performed (Table 3) . Fifteen patients (33%) needed microvascular reconstruction . Eleven patients (24%) underwent an EC-IC bypass . Intracranial reconstruction was needed in seven patients (15%). The types of intracranial reconstruction performed included aneurysmorrhaphy, MCA and ACA end-to-end and end-to-side anatomosis, and MCA branch transposition . The outcome from surgery was divided into five groups based on the Karnofsky scale : excellent, good, fair, poor, and dead [7] .

Results Table 4 summarizes the results of indirect surgery . There was no case of permanent neurological deficit as a result of EC-IC bypass and gradual occlusion of the ICA . In

Table 2 . Clinical Presentation of Patients Presentation Location of aneurysm

No . of

cases

SAH

Mass effect

TIA

Seizure

Cavernous carotid 15 2 12 0 Ophthalmic 14 5 8 0 0 0 Posterior communicating 3 3 0 1 1 Carotid bifurcation 3 0 14 6 0 2 MCA 22 0 5 0 0 AComA 5 32 (51%) 3(5%) 3 (5%) Totals 62 24(39%) Abbreviations : AComA, anterior communicating artery ; MCA, middle cerebral artery ; SAH, subarachnoid hemorrhage ; TIA, transient ischemic attack.



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Table 4 . Rerulbr of Indirect Surgery Result at last follow up Type of operation

No. of cases

EC-IC bypass and gradual occlusion of proximal ICA STA-proximal MCA bypass and trapping of aneurysm (abrupt occlusion of proximal ICA) Total

10

9

(I

(

3

I

16

Excellent

Fair

Good

12 (75%)

1 (6%)

I (6%)

Poor 0

Dead 0

1

1(6%)

1(6%)

Abbreviations : EC-IC, extracranial-intracraniah ICA, internal carotid artery ; MCA, middle cerebral artery ; STA, superficial temporal artery .

one patient, the GIA remained patent 10 days after the ICA occlusion, and so a craniotomy and ligation of the intracranial ICA was performed . Three patients with STA proximal MCA bypass and trapping sustained ischemic complications despite a patent bypass . As a result, there was one death, one fair result, and one poor result . The results of direct surgery are summarized in Table 5 . Eighty-five percent of the patients had an excellent or good outcome . The mortality was 4% . Twelve of the 13 patients with ophthalmic GIA had an excellent or good outcome . In one patient the aneurysm ruptured during the craniotomy . The patient died despite clipping of the GIA and prophylactic EC-IC bypass . Two of the three patients with posterior communicating artery GIA had an excellent result . The remaining patient was grade I V preoperatively and, in spite of some improvement after surgery, remained severely disabled . Two of the three patients with carotid bifurcation GIA had an excellent or good outcome . The third patient had excision of the dome of the aneurysm and an aneurysmorrhaphy performed . After this was performed, no blood flow was observed in the MCA . A MCA thrombectomy was performed bur this did not seem to reestablish flow. A STA-MCA bypass was then performed distal to the area of occlusion . This patient sustained a cerebral infarction and was hemiparetic postoperatively . Eighteen of the 23 patients with MCA GIA had a

good or excellent outcome . The single postoperative death in this group was in a patient who was grade IV preoperatively . Microvascular reconstruction was required in 10 cases because of compromise of blood flow in the distal MCA as a result of surgery to obliterate the aneurysm . The reconstruction was performed with good or excellent results in eight cases and fair results in two cases . All five patients with anterior communicating artery giant aneurysms had a good or excellent outcome . In two patients, microvascular reconstruction was necessary and performed with excellent results . Table 6 summarizes the type and outcome of microvascular reconstruction . Among patients who had direct surgery, 80% of patients who underwent vascular reconstruction and 87% of patients who did not need microvascular reconstruction had a good or excellent outcome (Table 7) . Overall, 84% of the 62 patients with GIA had an excellent or good outcome . The mortality was 5%, and 3% had a poor result .

Discussion The best treatment for an intracranial aneurysm is direct surgical clipping of the aneurysm with preservation of the parent vessel. However, this is not always possible and other strategies have to be considered, Proximal carotid ligation reduces the stress on the aneurysm wall

Table 5 . Results of Direct Surgery Location of aneurysm Ophthalmic Posterior communicating Carotid bifurcation MCA AComA Total

No. of cases

Excellent

13

10 2 1 12 4 29 (63%)

3 3 22

5 46

Abbreviations : AComA, anterior communicating artery ; MCA, middle cerebral artery .

Result, of last medical follow up Good Fair 2 0 1 6 1 10 (22%)

0 0 1

4(9%)

Poor 0 1 0 0 0 1 (2%)

Dead 1 0 0 0 2 (4%)



Giant Aneurysm

Table 6.

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Type and Outcome of Vascular Reconstruction

Location of aneurysm

Type of reconstruction

No. of cases

outcome Excellent-2 Died-1 Fair

Ophthalmic

STA-MCA Bypass

3

Carotid bifurcation

Aneurysmorrhaphy, MCA thrombectomy, STA-MCA bypass STA-MCA Bypass

1

Saphenous vein bypass

2

Aneurysmorrhaphy and STA-MCA bypass Aneurysm excision and MCA-MCA end-to-end anastomosis Aneurysm excision and MCA-MCA end-to-end anastomosis and STA-MCA bypass End-to-side MCA branch transposition Aneurysmorrhaphy and Al-A2 end-to-end anastomosis ACA-ACA end-to-side anastomosis

I

MCA

Anterior communicating

Excellent-2 Good-1 Good-1 Fair-1 Excellent

3

Excellent Good

Excellent Excellent Excellent

Abbreviations : ACA, anterior cerebral artery ; MCA, middle cerebral artery ; STA, superficial temporal artery .

and promotes thrombosis of the aneurysm [12) . Although we have treated smaller aneurysms in the cavernous sinus with direct surgery [4), we have not attempted direct surgery on cavernous GIAs because it is technically difficult, it is associated with morbidity and mortality [5], and there is a safer alternate treatment-carotid ligation-available . There are several variations in performing proximal carotid occlusion . Swearingen and Heros [29) reported on common carotid artery ligation in eight patients with GIA with computed tomography (CT) scan thrombosis of seven GIAs after the ligation . Unfortunately, evidence of thrombosis on CT scan does not necessarily mean that the aneurysm is totally obliterated, and rupture of such "thrombosed" aneurysms has been reported [16] . Internal carotid artery ligation should, on theoretical grounds, lead to a higher incidence of cavernous sinus aneurysm thrombosis, as the ICA usually becomes thrombosed up to the ophthalmic artery after ICA ligation . The ischemic complication rate of ICA occlusion is higher than common carotid artery occlusion [20] . Microvascular techniques have been used to perform prophylactic EC-IC bypass procedures and this has re-

duced the ischemic complications from carotid ligation [9,24,25] . Only a minority of patients need an EC-IC bypass before ICA occlusion . However, since there is no reliable way of selecting patients who do not need EC-IC bypass, we feel it is prudent to perform a prophylactic EC-IC bypass in all cases of elective ICA occlusion, especially since the morbidity and mortality associated with EC-IC bypass is low [8] . Embolism has been considered to be a major cause of ischemic complication after carotid ligation with or without an EC-IC bypass (18,19] . Trapping of a cavernous GIA by occlusion of the ICA in the neck and intracranially should reduce embolic complications . In our series, 50% of the six patients developed ischemic complications when trapping was performed immediately after the completion of the EC-IC bypass. The abruptness of the carotid occlusion may have been responsible for the ischemic complications, although there are reports that abrupt occlusion is safe [18,19) . There were three episodes of transient reversible neurologic deficits when gradual occlusion of the ICA was performed after a prophylactic EC-IC bypass [3) . When this was done under heparinization, there were no

Table

7 . Comparison of Results in Patients with Direct Surgery Who Underwent Vascular Reconstruction with Those Who Did Not Need Vascular Reconstruction Results of last follow up Type of direct surgery

No . of cases

With reconstruction Without reconstruction Total

15 31 46

Excellent 9 20 29 (63%)

Good 3 7 10 (22%)

Fair 2 2 4 (9%)

Poor 0 1 1 (2%)



l2

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Ausman et al

Figure 2 . Preoperative and postoperative rightca-

rotid angiography of a patient with a right MCA GIA . Clipping of the aneurysm caused compromise of the parent vessel . An EC-IC bypass was performed. The distal MCA is filled via the superficial temporal artery on the postoperative angiogram .

ischemic complications . When an EC-IC bypass is performed distal to an aneurysm, the change in hemodynamics can cause rupture of the aneurysm [16,211 . In gradual occlusion of the carotid artery, this risk exists until the carotid is occluded and the aneurysm becomes thrombosed . In one patient, the aneurysm remained patent 10 days after proximal carotid ligation and so the aneurysm was trapped by ligating the intracranial ICA .

Figure 3. Preoperative and postoperative right ca-

rotid angiography of a patient with a right MCA GIA . The aneurysm was excised and the MCA reconstructed with an end-to-end anastomosis .

Direct surgery allows for definitive exclusion of the aneurysm from the circulation . This may be by clipping or ligation of the aneurysm, or by excision of the aneurysm and reconstruction of the parent vessel . Clipping is the preferred method, and with improvements in clip design, more GIAs are treatable with clips [141 . Thirtyone patients had clipping of GIAs without compromise of the parent vessels, with 87% having an excellent or good result . In the remaining 15 cases, microvascular



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Figure 4 .

A

(A) Preoperative right and left carotid angiography shows an anterior communicating artery aneurysm that fills via the left ACA . Clipping of the aneurysm compromised the left A2 segment . An end-to-side anastomosis of the left A2 to the right A2 was performed. (B) (Right) Postoperative angiography shows occlusion of the left Al segment proximal to the aneurysm (arrowhead) . (Left) The left A2 segment fills on the right carotid angiography (arrow .

B

reconstruction was needed to correct vascular compromise after the aneurysm was clipped or excised . Even with good angiographic studies, it is not possible to predict which patients will need reconstruction . A decision on whether a GIA can be clipped can only be made intraoperatively after the aneurysm is exposed

and its relationship to nearby vessels defined . We usually use temporary clipping before dissecting the GIA . Besides minimizing the risk of intraoperative rupture, temporary clipping helps collapse the aneurysm and facilitates its dissection . Five minutes before the temporary clips are applied, 1 g/kg of 20% mannitol and 250





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Table 8 .

Results of Operative Treatment of Giant Intracranial Aneurysms

Author Sonntag et al [231 Onuma and Suzuki [171 Drake [61 Yasargil [341 Symon and Vajda [301 Whittle et al [331 Hosobuchi ( 131 Heros [ l 11 Sundrand Piepgras[261 Ausman et al [Present)

No . of

cases

9 24 161 30

36 19 82 28 239 62

mg of thiopentone are administered intravenously . This provides cerebral protection and allows for 30-40 minutes of safe temporary occlusion 127, 281 . In 15 patients, microvascular reconstruction was necessary . There was narrowing of the ICA after clipping of an ophthalmic GIA in three cases . In these patients, a STA-MCA bypass was performed . In a patient with a carotid bifurcation GIA, aneurysm sac excision and aneurysmorrhaphy was performed . The MCA occluded after the aneurysmorrhaphy, and blood flow in the area could not be reestablished despite thrombectomy procedure . A STA-MCA bypass was then performed . In five patients there was compromise of the distal MCA after clipping of the MCA GIA, and so an EC-IC bypass was performed . In four patients, the GIA sac was excised and the MCA was reconstructed . The microanatomical basis for this reconstruction has previously been described [1,2,31,32] . Whenever possible we prefer to perform a local intracranial reconstruction rather than an EC-IC bypass after excision of the aneurysm sac because the procedure takes less time and hence reduces the temporary clip occlusion time . Extracranial-intracranial bypass is not an option when the ACA is compromised . When the anterior communicating artery GIA was excised in two patients, local intracranial reconstruction was necessary . The microanatomical basis for this reconstruction has previously been described [1, 10,351 . The results of the 15 patients requiring microvascular reconstruction were similar to those who did not require microvascular reconstruction, with 84% of the patients having an excellent or good result. The ability to use microvascular reconstruction techniques when necessary allowed us to provide definitive treatment of all anterior circulation GIAs that did not involve the cavernous sinus . Figures 2-4 show examples of microvascular reconstruction in the treatment of GIAs . Table 8 lists the operative results of several series . The results cannot be strictly compared because selection criteria of patients, timing of surgery, and preopera-

Outcome Fair/Poor

Excellent/Good 5 (55%) 12 (50% 115 (71%) 20(67%) 31 (86%) 12(63%) 69 (84% 23(82%) 180 (75%) 52 (84%)

Dead

1

3 (33%)

7 21

5 (21%) 25 (16%)

7

3(10%)

2

3(8%) 1 (5%) 6(7%)

6

3(11%)

14

45 (19%) 3 (5%a)

7

tive grade of the patients in the series listed are different . Our operative results are similar to those listed in Table 8 . Figure 5 describes our present method for treating anterior circulation GIAs and the role of vascular reconstruction in this treatment . In summary, our experience with anterior circulation GIAs suggests that the best treatment for cavernous carotid GIAs is EC-IC bypass followed by gradual occlusion of the ICA under heparinization . Ischemic complications from hypoperfusion appear to be a greater problem than embolization in elective carotid occlusion. By using microvascular reconstruction techniques when

H-

ImoNnCmmda5lnu.?

No-i

~, vatnN

yM'i*

uw

E0 11= i 50% OtrANlen a ICA

I

I

w

Ms

Figure 5 .

Algorithm for anterior circulation GIA surgery .



Giant Aneurysm

necessary, all anterior circulation GIAs that do not involve the cavernous sinus can be treated with direct surgery . The results of patients who need reconstruction are similar to those who do not need reconstruction . Overall, 84% of patients with anterior circulation GIAs had an excellent or good outcome after surgery . The mortality was 5% .

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giant carotid aneurysm after superficial temporal-middle cerebral artery bypass and internal carotid occlusion . Neurosurgery 1985 ;16 :177-84 . 17. Onuma T, Suzuki J . Surgical treatment of giant intracranial aneurysms . J Neurosurg 1979;51 :33-6 . 18. Peerless SJ . Commentary . Neurosurgery 1982 ;10 :571 . 19- Peerless S), Hampf CR . Exrracranial to intracranial bypass in the treatment of aneurysms . Clin Neurosurg 1985 ;32 :114-54 . 20. Sabs AL, Perret GE, Locksley HB, Nishioka H . Intracranial aneurysms and subarachnoid hemorrhage . A cooperative study . Philadelphia : JB Lippincott, 1969. 21 . Scott RM, Liu HC, Yuan R, Adelman L Rupture of a previously unruptured giant middle cerebral artery aneurysm after exrracranial-inrracranial bypass surgery . Neurosurgery 1982 ;10 :600-3 . 22 . Sindou M, Keravel Y . Surgical occlusions of the parent artery for treatment of giant aneurysms in the anterior circulation . In : Kikuchi M, Fukushima T, Watanabe K, eds . Intracranial aneurysms . Niigata: Nishimura, 1986 :258-72 . 23 . Sonntag VHK, Yuan R, Stein BM . Giant intracranial aneurysms ; a review of 13 cases . Surg Neurol 1977 ;8 :81-4 . 24 . Spetzler RF, Schuster H, Roski RA . Elective extracranial-inrracranial bypass in the treatment of inoperable giant aneurysms of the internal carotid artery . J Neurosurg 1980 ;53 :22-7 . 25 . Spetzler RF, Selman W, Carter LP . Elective EC-IC bypass for unclippable intracmnial aneurysms . Neurol Res 1984 ;6 :64-8 . 26 . Sundt TM Jr, Piepgras DG. Surgical management of giant intracranial aneurysms. In : Kikuchi M, PukushimaT, Watanabe K, eds . Intracranial aneurysms. Niigata : Nishimura, 1986:324-35 . 27 . SuaukiJ . Cerebral aneurysms . Experience with 1000 directly operated cases. Tokyo : Neuron Co, 1979:330-65 . 28 . Suzuki J . New brain protective agents and clinical use . In : Suzuki J, ed. Advances in surgery for cerebral stroke . Tokyo : Springer, 1988 . . 29 Swearingen B, Hems R . Common carotid occlusion for unclippable carotid aneurysms : an old but still effective operation . Neurosurgery 1987 ;21 :288-95 . 30 . Symon L, Vajda J . Surgical experiences with giant inrracranial aneurysms . J Neurosurg 1984 ;61 :1009-28. 31 . Umansky F, Games F, Dujovny M, Din FG, AusmanJi, Michandani HG, Berman SK . The perforating branches of middle cerebral artery . J Neurosurg 1985 ;62 :261-8 . 32. Umansky F, Montoya Juarez S, Dujovny M, Ausman JI, Diu FG, Games F, Mirchandani HG, Ray WJ. Microsurgical anatomy of the proximal segments of the middle cerebral artery . J Neurosurg 1984 ;61 :458-67 . 33 . Whittle IR, Dorsch NW, Besser M . Giant intracranial aneurysms : diagnosis, management and outcome . Sung Neurol 1984 ; 21 :218-30. 34 . Yasargil MG . Giant intracranial aneurysms . In : Microneurosurgery . Vol . 11. Stuttgart: George Theime, 1984 :296304 . 35 . Yokoh A, Ausman JI, Dujovny M, Diu FG, Berman SK, Sanders J, Mirchandani HG . Anterior cerebral artery reconstruction . Neurosurgery 1986 ;19 :26-35 .