Middle cerebral artery aneurysm case series
A study of Gou et al. from the Beijing Neurosurgical Institute, included 285 cases of middle cerebral artery aneurysm surgery with MEP monitoring. The effects of MEP changes on postoperative motor function were assessed, and the key time point for minimizing the incidence of postoperative motor dysfunction was found through receiver operating characteristic (ROC) curve analysis. Motor dysfunction was significantly associated with the occurrence of MEP changes, and patients with irreversible changes were more likely to suffer motor dysfunction than were those with reversible changes. The critical duration of MEP changes that minimized the risk of postoperative motor dysfunction was 8.5 min. This study revealed that MEP monitoring is an effective method for preventing ischemic brain injury during surgical treatment of MCA aneurysm and proposes a critical cutoff for the duration of MEP deterioration of 8.5 min for predicting postoperative motor dysfunction 1).
Esposito et al. from the Department of Neurosurgery, Clinical Neuroscience Center Zurich, report on a consecutive case-series of 50 patients who received clipping of 54 ruptured/unruptured middle cerebral artery aneurysm (MCA-aneurysms) by means of lateral supraorbital approach (LS) or minipterional craniotomy. The distance between MCA (M1)-origin and the aneurysmal neck is key to select the approach: LS was used for MCA-aneurysm located <15mm of the M1-origin and MP for MCA-aneurysms located ≥15mm of the M1-origin.
11 out of 50 patients presented with subarachnoid hemorrhage (10 ruptured MCA aneurysms). Overall, 59 aneurysms were successfully clipped (54 of the MCA). The mean distance between the M1-origin and the aneurysmal neck was 10.1-mm (range: 4-17mm) for patients treated by LS and 20-mm (range: 15-30mm) for MP. All but one MCA aneurysms were successfully treated. At last follow-up (mean 14 months), no reperfusion of the clipped aneurysms was observed.
The strategy for selecting the keyhole approach based on the depth of the aneurysm within the Sylvian fissure is efficient and safe. They suggest the use of LS approach when the aneurysm is located <15mm from the M1-origin and MP approach when the aneurysm is located ≥15mm from the M1-origin 2).
Eighteen intracranial aneurysms, including 13 unruptured and 5 ruptured aneurysms, were treated with LVIS Jr stent-assisted coil embolization.
A total of 18 stents were successfully delivered to the target aneurysms, and the technical success rate was 100%. There was complete occlusion in 8 (44.4%) of 18 cases, neck remnants in 7 (38.9%) cases, and partial occlusion in 3 (16.7%) cases. In-stent thrombosis occurred in 1 case, and the symptoms disappeared after transvenous tirofiban injection. The modified Rankin Scale score at discharge was 0 in 14 patients, 1 in 3 patients, and 2 in 1 patient.
The LVIS Jr stent provided excellent trackability and deliverability and is safe and effective for the treatment of wide-necked MCA aneurysms with tortuous and smaller parent vessels 3).
Clinical and radiological data of 103 patients interdisciplinary treated for unruptured MCA aneurysms over a 5-year period were analyzed in endovascular (n = 16) and microsurgical (n = 87) cohorts. Overall morbidity (Glasgow Outcome Score <5) after 12-month follow-up was 9 %. There was no significant difference between the two cohorts. Complete or “near complete” aneurysm occlusion was achieved in 97 and 75 % in the microsurgical, respective endovascular cohort. A “complex” aneurysm configuration had a significant impact on complete aneurysm occlusion in both cohorts, however, not on clinical outcome. Treatment of unruptured MCA aneurysms can be performed with a low risk of repair using both approaches. However, the risk for incomplete occlusion was higher for the endovascular approach in this series 4).
Five hundred forty-three patients with 631 MCA aneurysms were managed with a “clip first” policy, with 115 patients (21.2%) referred from the Neurointerventional Radiology service and none referred from the Neurosurgical service for endovascular management.
Two hundred eighty-two patients (51.9%) had ruptured aneurysms and 261 (48.1%) had unruptured aneurysms. MCA aneurysms were treated with clipping (88.6%), thrombectomy/clip reconstruction (6.2%), and bypass/aneurysm occlusion (3.3%). Complete aneurysm obliteration was achieved with 620 MCA aneurysms (98.3%); 89.7% of patients were improved or unchanged after therapy, with a mortality rate of 5.3% and a permanent morbidity rate of 4.6%. Good outcomes were observed in 92.0% of patients with unruptured and 70.2% with ruptured aneurysms. Worse outcomes were associated with rupture (P = .04), poor grade (P = .001), giant size (P = .03), and hemicraniectomy (P < .001).
At present, surgery should remain the treatment of choice for MCA aneurysms. Surgical morbidity was low, and poor outcomes were due to an inclusive policy that aggressively managed poor-grade patients and complex aneurysms. This experience sets a benchmark that endovascular results should match before considering endovascular therapy an alternative for MCA aneurysms 5).
Ogilvy et al., reviewed 65 middle cerebral aneurysms in 62 patients operated on over a 5-year interval where a choice of operative approach was made based on preoperative evaluation of available radiological studies.
The superior temporal gyrus was used when intraparenchymal hematoma was present in the temporal lobe or when the length of the middle cerebral artery trunk was long (average length 2.44 +/- 0.41 SE cm). This approach was used in 20 operations on 22 aneurysms. The sylvian fissure approach was used in cases where the middle cerebral artery main trunk was short (1.32 +/- 0.41 SE cm) or the direction of the aneurysm was favorable. This approach was used in 38 operations. In 4 operations (5 aneurysms) we combined the two approaches to remove clot, obtain adequate exposure, and secure control of the proximal MCA.
In most cases of MCA aneurysms the decision as to which surgical approach to use is made preoperatively depending on the presence of intraparenchymal clot, size of aneurysm, direction of aneurysm, and length of the proximal middle cerebral artery 6).