Giant Middle Cerebral Artery Aneurysm:

Surgical repair by a mixed remodelling technique.

Boris Zurita –Cueva M.D. and Jaime Velasquez MD.

Hospital de la Policia Nacional

Guayaquil-Ecuador.

e-mail:fedez95@gye.satnet.net

For more technical information go to: www/medicosecuador.com/revecuatneurol

Abstract: The key for  treatment of giant intracranial aneurysms is its exclusion  from the circulation and restoration of the normal anatomy. This report  describes the technique of the middle cerebral artery bifurcation reconstruction  using microsuture aneurysmorraphy and clipping. 

Key –Words: Giant aneurysm, Middle cerebral artery, aneurysmorrhaphy.  

Case report and Surgical Technique: 

A 67 year- old  right handed woman presented with complaints of headache and fever fifteen days before admission. She was diagnosed of paludism, but during her stance at the hospital she suddenly presented decreased of level of consciousness that evolves to coma.

On admission the patient  was comatose , with a score of 10 in Glasgow coma scale,  and a right hemiparesis.

Computerized tomography (CT)  revealed a 4cm mass in the left insular region with perilesional oedema and subaracnoid haemorrhage at this site.

Cerebral angiography confirmed the presence of a partially trombosed  giant aneurysm at the left MCA bifurcation.

The patient’s level of consciousness evolves to Glasgow 14 , two weeks  after admission , time when we decided to operate.    

A right pterional approach was performed ,with extensive drilling of orbitary fissure and anterior clinoid process, in order to give space in front and below de aneurysm and expose de M1 segment of the right middle cerebral artery. The we opened  the sylvian fissure in a distal to medial manner. We took care not to close the M1 segment until subpial dissection of the aneurysm was completed. We observed that both M2 segments were incorporated in its wall and originate from the aneurysm dome making impossible the normal clipping procedure of the aneurysm. We tried many times to reconstruct the anatomy of middle cerebral artery with a 20mm clip but the pulse of the dome slipped out the clip. We proceed then to open the aneurysm dome with a Nº11 knife, clipping previously the M1 segment. A microendarterectomy and blood clots evacuation was performed. We proceed with resection of the aneurysm dome and reconstruction  with 8-0 micro suture of the parent artery.  A small neck rest of the aneurysm was created and this was occluded conventionally with the 20mm clip. All the procedure lasted 30 minutes , with two periods of 15 minutes of temporal clipping,  protected with  barbiturate and manitol administration . At the end of the  reconstruction we observed  surprisingly the increased  flow and diameter in both M2.

 segments.

Posoperative course:

The patient experienced an uneventful   postoperative course. The patient´s neurological examination improved slowly ten days after.

The patient returned to her previous activity and now is neurologically intact. The magnetic resonance angiography showed disappearance of the aneurysm and preservation of the  vascular anatomy of the region.

Discussion: 

Giant intracranial aneurysms, defined as greater than 2.5 cm in diameter, represent about 5 % of all intracranial aneurysms and usually originate from carotid artery.

Middle cerebral artery aneurysms represent  13 % of this group. They produce symptoms exerting mass effect, but some debute with subaracnoid haemorrhage) (5,11). Occasionally, they may present with ischemic symptoms related to distal emboli. 

The surgical treatment is a real challenge because the efferent vessels are incorporated at the aneurysm wall.

They have intraluminal clots and their big size make them impossible to clip.

Indirect surgical treatment do not warrant  cure and have high degree of complications. Carotid cervical occlusion has a 27 % of ischemic problems  (7,9,10,12,13). 

Extra-intracranial bypass  and clipping the parent  artery is another alternative. Unfortunately ischemic complications  have been reported even when the vascular bypasses were patent (3,4,6,14,15). 

Wrapping the aneurysms dome  with muscle or muslin does not exclude a new bleeding episode and distal embolization (7). 

Definitive the ideal treatment is aneurysms exclusion of circulation and reconstruction of the normal anatomy of the region  (2,16,17). 

Sundt reconstructed giant aneurysmatic lesions performing a tromboendarterectomy  and clipping (8,18,19). 

We have done a variant of this technique :First we performed de endarterectomy ,then we resect  part of the aneurysm dome , leaving part of it to form later a new artery by microsuture and a standart clip. This technique avoids  the use of booster clips  and secures  the correct reconstruction of the typical middle cerebral artery anatomy .

This technique is reported like a viable option in the management of difficult giant aneurysms of the MCA. We recommended  direct microsurgical approach and reconstruction of this kind of lesion.  

References:

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Figures:   

Fig.1:Angiography shows a giant aneurysm of the left middle cerebral artery

Fig.2: Intraoperative view of the aneurysm. (A transitory clip is in the right M1 segment)

Fig.3 : Complete reconstruction of the middle cerebral artery anatomy. (Observe both M2 segments TS, Ti)

Fig.4 : Posoperative MRI angiography showing patency of both M2 segments and reconstruction of normal anatomy of middle cerebral artery bifurcation (yellow arrow).