Treatment Strategies for Complex Internal Carotid Artery (ICA) Aneurysms: Direct ICA Sacrifice or Combined with Extracranial-to-Intracranial Bypass

Sacrificing Internal Carotid Artery-External Carotid Artery-Radial Artery-Middle Cerebral Artery Bypass for the Treatment of Complex Intracranial Artery Cavernous Sinus Aneurysms

The treatment of complex intracranial aneurysms has always been a great challenge in neurosurgery. Craniotomy has a high risk of clipping, there is a risk of rupture at any time, endovascular embolization is relatively low risk, but expensive and easy to relapse, the best treatment needs to be further discussed. Cavernous sinus aneurysms with pituitary adenomas are rare. This case reports a case of complex intracranial aneurysms. Chief complaints are: (1) blepharoptosis with blurred vision for 1 year, (2) headache for 3 days, and (3) digital subtraction angiography showed right internal carotid artery cavernous sinus aneurysm. Combined with the patient's condition and family condition, the external carotid artery-radial artery-middle cerebral artery bypass was selected. After surgical treatment, the symptoms of the patients were improved, the postoperative recovery was good, and the condition was stable. After follow-up, the patient's brain computed tomography showed intra-aneurysm thrombosis.

Reconstructive endovascular treatment of petrous ICA pseudoaneurysm in skull base osteomyelitis: a hidden catastrophe

Skull base osteomyelitis can be more life-threatening in immunocompromised patients and patients with diabetes. Here, we present a case of a petrous internal carotid artery pseudoaneurysm resulting from skull base osteomyelitis in a diabetic male in his 50s. This case report highlights the need to be conscious of the various complications associated with skull base osteomyelitis, be proficient in detecting them and treat them as early as possible for better outcomes. After adequate control of the disease process with medical treatment, immediate management of the aneurysm with balloon angioplasty and stenting was done. Acknowledging the trivial nasal and ear bleed, radiological evaluation is necessary to rule out rare complications like pseudoaneurysms in a diagnosed case of skull base osteomyelitis. In the discussion, we have cited the various treatment methods and similar cases of pseudoaneurysm caused by osteomyelitis. Currently, the patient continues to live a disease and disability-free life.

Superficial Temporal Artery-Middle Cerebral Artery Bypass Combined with Internal Carotid Ligation in Treating Complex Internal Carotid Aneurysms. The Willis Polygon Score is an Effective Solution for Developing Countries

OBJECTIVE

Internal carotid complex aneurysms (ICCAs) management is challenging. Ligating the internal carotid artery (ICA) combined with Superficial Temporal Artery-Middle Cerebral Artery (STA-MCA) anastomosis is an effective treatment option. Balloon test occlusion (BTO) assessments for preoperative decision-making are unaffordable in developing countries. This article discusses the study of Willis polygon (WP) segments as an option and suggests a score for decision-making. Herein, we report the outcomes of a series of patients treated for ICCA aneurysms at a single institution.

METHODS

From September 2016 to December 2020, we conducted a retrospective cohort study that analyzed data from patients with ICCAs. Among them, 9 patients received treatment involving ICA ligation combined with STA-MCA anastomosis. Partial or total carotid ligation was determined by using the WP score (WPS).

RESULTS

All Patients underwent STA-MCA anastomosis, in addition to total ICA ligation in 7 patients and partial ICA ligation in 2 patients with a WPS of 7 and 5, respectively. Patients with partially ligated carotid arteries were referred to an overseas neurointerventional center 12 months after surgery. As the BTO test was negative, they underwent ICA occlusion by coiling. Postoperative clinical outcomes did not change in 8/9 patients. In 1 patient, we reported a minor parietal stroke; the patient recovered completely after 6 months. Total aneurysm exclusion by thrombosis was achieved in 7/9 patients after total ICA ligation alone and in 2/9 patients after partial ICA ligation combined with coiling.

CONCLUSIONS

Limited access to endovascular assessment techniques such as BTO poses challenges in managing ICCAs. The WPS for decision-making appears to be a simple and safe option. In addition to STA-MCA bypass surgery, total or partial ICA ligation may be proposed depending on the WPS. After 12 months, patients with low WPS who underwent partial ICA ligation combined with bypass had postoperative normal BTO.

Proximal Internal Carotid Artery Occlusion and Extracranial-Intracranial Bypass for Treatment of Fusiform and Giant Internal Carotid Artery Aneurysms

OBJECTIVE

To discuss the treatment of intracranial fusiform and giant internal carotid artery (ICA) aneurysms via revascularization based on our institutional experience.

METHODS

An institutional review board-approved retrospective analysis was performed of patients with unruptured fusiform and giant intracranial ICA aneurysms treated from November 1991 to May 2020. All patients were evaluated for extracranial-intracranial (EC-IC) bypass and ICA occlusion.

RESULTS

Thirty-eight patients were identified. Initially, patients failing preoperative balloon test occlusion were treated with superficial temporal artery (STA)-middle cerebral artery (MCA) bypass and concurrent proximal ICA ligation. We then treated them with STA-MCA bypass, followed by staged balloon test occlusion, and, if they passed, endovascular ICA coil occlusion. We treat all surgical medically uncomplicated patients with double-barrel STA-MCA bypass and concurrent proximal ICA ligation. The mean length of follow-up was 99 months. Symptom stability or improvement was noted in 85% of patients. Bypass graft patency was 92.1%, and all surviving patients had patent bypasses at their last angiogram. Aneurysm occlusion was complete in 90.9% of patients completing proximal ICA ligation. Three patients experienced ischemic complications and 4 patients experienced hemorrhagic complications.

CONCLUSIONS

Not all fusiform intracranial ICA aneurysms require intervention, except when life-threatening rupture risk is high or symptomatic management is necessary to preserve function and quality of life. EC-IC bypass can augment the safety of proximal ICA occlusion. The rate of complete aneurysm occlusion with this treatment is 90.9%, and long-term bypass graft-related complications are rare. Perioperative stroke is a major risk, and continued evolution of treatment is required.

Deliberate Parent Artery Sacrifice Guided by Intraoperative Neurophysiological Monitoring During Complex Surgical Clipping of a Ruptured Anterior Communicating Artery Aneurysm

Aneurysms arising from the anterior communicating artery (ACOA) are the most common intracranial aneurysms encountered. Most aneurysms can be treated with surgical clipping or endovascular coiling; however, there are times when parent vessel sacrifice (PVS) is necessary such as aneurysms with fragile necks or large/giant aneurysms. Application of intraoperative neurophysiological monitoring (IONM) can assist in guiding permissive temporary vessel occlusion during complex aneurysm clippings. However, to-date there is no literature that describes how IONM can be used as a predictor of post-operative neurological status when PVS is employed or as a guide to determine whether PVS is safe. We present a case where IONM guided the sacrifice of the A1 and anterior communicating arteries after 2 hours and 25 min of temporary vessel occlusion. No attenuation was noted in the IONM at any point during the procedure, and the IONM predicted the patient would awake neurologically intact.

Giant Aneurysm Management

The treatment of giant aneurysms has always been a challenge in the field of neurovascular disease. Giant aneurysms are larger in size and are associated with thrombosis development and the calcification of the aneurysmal wall and neck, which often interfere with direct clipping. Most giant aneurysms have a wide neck with an incomplete thrombus, making complete embolization almost impossible. Giant aneurysms of different sites have entirely different hemodynamic characteristics. Moreover, aneurysms at the same site may exhibit very different hemodynamics among different individuals. Therefore, careful assessment of each case is required before and during treatment to develop and carry out an individualized treatment plan.

Lesion Trapping with High-Flow Bypass for Ruptured Internal Carotid Artery Blood Blister-Like Aneurysm Has Little Impact on the Anterior Choroidal Artery Flow: Case Series and Literature Review

OBJECTIVE

To examine the relationship between trap location and cerebral infarction in the anterior choroidal artery (AChA) region and associated risks in ruptured internal carotid artery blood blister-like aneurysm (BLA) treatment with high-flow bypass and lesion trapping.

METHODS

We included 26 patients diagnosed with BLAs and treated with high-flow bypass and trapping. We examined clinical characteristics including age, aneurysm trap location, final prognosis, cerebral infarction on postoperative magnetic resonance imaging, and modified Rankin Scale score at discharge. We also searched the literature for similar studies.

RESULTS

The modified Rankin Scale score at discharge was 0-2 in 20 patients, 3-5 in 2 patients, and 6 in 2 patients. In 19/26 patients (73.1%), the trapped segment was between the posterior communicating (PcomA) and the ophthalmic arteries. In 2 patients (7.7%), the trapped segment included the PcomA and the AChA; in 4 patients (15.4%), the trapped segment was within the PcomA. In these patients, the PcomA was occluded, and blood from the high-flow bypass flowed out to the AChA alone. No patient showed cerebral infarction. Our systematic review identified 70 patients. Of all 96 patients, 12 had AChA cerebral infarction; however, the infarction affected the prognosis of only 2 patients.

CONCLUSIONS

When treating BLAs with high-flow bypass and lesion trapping, the frequency of AChA cerebral infarction is low even when the PcomA is occluded, leaving the AChA as the only outflow vessel during high-flow bypass. However, PcomA occlusion may be associated with risks when treating patients with advanced arteriosclerosis near C1-2.

A Hybrid Strategy for Patients With Complex Cerebral Aneurysm: STA-MCA Bypass in Combination With Endovascular Embolization

Objective: This work aims to present our experience of patients with complex cerebral aneurysm treated with a hybrid approach: superficial temporal artery–middle cerebral artery (STA–MCA) bypass in combination with endovascular exclusion of the aneurysm.

Method: Patients with aneurysms deemed unclippable and uncoilable were included. All patients were treated with a hybrid approach. After STA–MCA bypass, the parent artery was temporarily occluded. If the intraoperative motor evoked potential (MEP) and somatosensory evoked potential (SEP) waveforms remain normal and last for 30 min, the aneurysm and te parent artery will be embolized permanently with detachable balloons or coils.

Results: A total of 20 patients with 22 aneurysms were included in this study. There were 13 women and 7 men, with an average age of 42.5 years. Intraoperative angiography showed the good patency of all the STA grafts, and neither SEP nor MEP abnormalities were detected. After the parent artery and the aneurysm were occluded, the intraoperative angiography showed an immediately successful exclusion of the aneurysm in 20 aneurysms and immediate contrast stasis in two. All patients recovered uneventfully without ischemic or hemorrhagic complication. Angiography at 6-month follow-up showed the total obliteration in 20 aneurysms. Two aneurysms showed residuals and were recoiled. All STA grafts showed a good patency, and the mean graft flow was 124.2 ml/min.

Conclusion: STA–MCA bypass in combination with endovascular exclusion is an appropriate option for patients with complex cerebral aneurysms that are not amenable to direct surgical clipping or endovascular embolization.

[Anatomical bases of brain revascularization: choosing an extra-intracranial bypass option]

Surgical brain revascularization is an important treatment for acute or chronic ischemia, intracranial aneurysms and skull base tumors. Individual anatomy of brain vessels should be clearly understood for this procedure. Variants of collateral cerebral blood flow in patients with cerebrovascular diseases depend on individual characteristics of circle of Willis and reserve mechanisms of collateral circulation. These anatomical variations require careful preoperative planning to choose the optimal revascularization option.

The Rate of Symptomatic Ischemic Events after Passing Balloon Test Occlusion of the Major Intracranial Arteries: Meta-Analysis

BACKGROUND

Balloon test occlusion is a widely used method for predicting tolerance of vessel occlusion in the treatment of aneurysms, fistulae, and head and neck neoplasms. However, the false-negative rate is variably reported due in part to the diversity of perfusion monitoring methods.

OBJECTIVE

To evaluate the rate of symptomatic ischemic events after a negative balloon test occlusion and determine whether perfusion monitoring methods contribute to differences in these rates.

METHODS

PubMed was systematically searched for studies between 1990 and 2020 that reported rates of ischemic outcomes of parental vessel occlusion in patients who passed balloon test occlusion. A generalized linear mixed model meta-analysis was performed. Results were expressed as the rate of symptomatic ischemic events after parental vessel occlusion without vessel bypass in patients who passed balloon test occlusion.

RESULTS

Thirty-two studies met the inclusion criteria. The overall pooled rate of ischemic events after passing balloon test occlusion was 3.7% (95% confidence interval [CI]: 1.7-7.8). This rate was 3.8% (95% CI: 1.1-12.8) when monitored with angiography, 2.2% (95% CI: 0.4-10.2) when monitored by a form of computed tomography, and 5.3% (95% CI: 1.2-20.4) when monitored by 2 or more methods of perfusion assessment. The complication rate of balloon test occlusion was 0.8% (95% CI: 0.2-2.7).

CONCLUSIONS

Balloon test occlusion results in a low rate of subsequent ischemic events, without conclusive evidence of variation between methods of perfusion assessment. The choice of method should focus on reduction of complication risk, experience of the interventional team, and avoidance of prolonged test occlusion times.

Early and midterm results of treatment of giant internal carotid artery paraclinoid aneurysms with trapping and flow diverters

BACKGROUND

Flow diverter devices (FDD) carry risks of postoperative complications when treating aneurysms with wide necks, stenosis, and severe tortuosity of the parent vessel. In this study, we evaluated early and midterm results for the treatment of giant paraclinoid aneurysms managed by trapping and endovascular deployment of FDD.

METHODS

Medical records were analyzed for patients with giant paraclinoid aneurysms treated between July 2008 and December 2017 at National Centre for Neurosurgery with either a flow diverter or by trapping the aneurysm with or without extracranial-intracranial (EC-IC) bypass surgery. We recorded age, sex, clinical presentation, treatment modality, morbidity, and mortality. Clinical outcomes were assessed using a modified Rankin scale (mRS).

RESULTS

Among 29 consecutive patients, 13 were treated with FDD, and 16 patients were managed by trapping the aneurysm, where 7/16 cases had preliminary EC-IC bypass. Of 16 trapping patients, six were trapped endovascularly and ten were trapped surgically. During the follow-up period (mean 33 months, range 6-96), total exclusion of the aneurysm from the circulation was observed 100% of aneurysms in the trapping group and 84.6% in the FDD group (P = 0.192). Early postoperative morbidity was observed in three (23%) cases in the FDD group, and four (25%) in trapping group (P = 0.525). The FDD group had one (7.7%) fatal complication due to stent occlusion and severe ischemic stroke after three months postoperatively, despite appropriate antiplatelet therapy. There were no mortalities in the trapping group (P = 0.149). The rate of mRS 0-2 did not differ significantly across groups at discharge (81.3% vs. 69.2%; P = 0.667), and all patients had mRS 0-2 at follow-up (P = 1.000).

CONCLUSIONS

FDD deployment for giant paraclinoid aneurysms results in comparable angiographic and clinical outcomes to aneurysm trapping. Despite implementation of modern endovascular treatment methods, aneurysm trapping remains a valuable treatment option in carefully selected patients with giant paraclinoid aneurysms.

Incision of the anterior petroclinoidal fold during clipping for securing the proximal space of an internal carotid artery-posterior communicating artery aneurysm: a technical note

Surgical clipping of an internal carotid artery (ICA)-posterior communicating artery (ICPC) aneurysm is often difficult in cases involving limited space to insert a clip at the proximal aneurysm neck hidden by the tent. In such cases, we perform incision of the anterior petroclinoidal fold to secure the proximal space for clip insertion. Between April 2013 and March 2018, we treated 89 ICPC aneurysm cases by clipping. Incision of the anterior petroclinoidal fold was performed in 15 of the 89 cases (16.8%). Fast imaging employing steady-state acquisition (FIESTA) magnetic resonance imaging (MRI) can indicate the locations of the aneurysm and tent and can help assess the need for tent incision. We widely dissected the distal sylvian fissure and sufficiently exposed around the aneurysmal space. We coagulated and cut the anterior petroclinoidal fold supra between the ICA and proximal neck of the aneurysm using a low-power bipolar system and needles or micro-scissors with care to avoid injury around structures such as the ICA, aneurysm, and oculomotor nerve. When using this strategy, we often select the Yasargil FT717 clip that has a curve along the skull base because of easy insertion. All cases showed complete aneurysm exclusion on three-dimensional computed tomography angiography, and there was no cerebral infarction, neurological deficit (such as hemiparesis), or oculomotor nerve palsy. Therefore, our strategy of incision of the anterior petroclinoidal fold during clipping for securing the proximal space of an ICA aneurysm is effective and safe.

Interval growth in an ICA bifurcation aneurysm treated with balloon occlusion, and possible contribution of vasa vasorum hypertrophy

We present a rare case of an ICA aneurysm recurrence despite treatment with ICA balloon occlusion. There was evidence of ICA recanalization bypassing the balloons on a catheter angiogram follow-up 1 year post-procedure. Although initially stable in size, at 5 years after the original procedure, the aneurysm demonstrated evidence of enlargement and on angiography there was further enlargement of the recanalized ICA around the occluding balloons. We postulate that this has been caused by increasing antegrade flow through hypertrophied vasa vasorum in response to persistently increased demand for blood flow by the ipsilateral hemisphere; this indirectly may have also contributed to some extent to the aneurysm enlargement.

Does Universal Bypass before Carotid Artery Occlusion Obviate the Need for Balloon Test Occlusion: Personal Experience with Extracranial-Intracranial Bypass in 23 Patients

Aim

Carotid artery ligation carries a potential risk of ischemic complications even in patients with good collaterals and adequate cross-circulation. Preoperative assessment through balloon test occlusion (BTO) is technically challenging and not feasible in all patients. We analyze our experience with universal bypass without performing detailed cerebrovascular reserve (CVR) studies in 23 patients before carotid artery ligation.

Patients and Methods

This was a retrospective analysis of the case records of 23 patients who underwent cervical carotid artery ligation for various indications since January 2009.

Results

The study included 21 patients with cavernous carotid aneurysms, one patient with a large fusiform petrous carotid aneurysm, and one patient with recurrent glomus jugulare encasing the cervical internal carotid artery. The initial 12 patients underwent preoperative BTO with hypotensive challenge. All patients underwent a bypass procedure followed by carotid artery ligation irrespective of the BTO findings. Patients who successfully completed a BTO underwent a low-flow superficial temporal artery to middle cerebral artery bypass. A high-flow extracranial-intracranial bypass using a saphenous vein graft from external carotid artery to middle cerebral artery was done in all patients who either failed the BTO or did not undergo BTO. We had two operative mortalities and one poor outcome. All the other patients had a good recovery with a Glasgow outcome score of 5 at the last follow-up. Graft patency rates were 81.1% in both the low-flow and high-flow groups.

Conclusion

Universal high-flow bypass is safe, effective, and should be preferred in all patients before carotid artery ligation. It obviates the need for detailed CVR assessment, especially in centers with limited resources.

Intraoperative Test Occlusion as Adjustment of Extracranial-to-Intracranial Bypass Strategy for Unclippable Giant Aneurysm of the Internal Carotid Artery

BACKGROUND

There is still a controversy for low-flow extracranial-intracranial or high-flow extracranial-intracranial bypass with proximal occlusion in the treatment of unclippable giant internal carotid artery aneurysms.

CASE DESCRIPTION

A 61-year-old woman presented with a 1-month history of double vision. Neuroimages revealed an unclippable giant internal carotid artery aneurysm located from the cavernous sinus to proximal site of the posterior communicating artery. Ipsilateral A1 of the anterior cerebral artery was hypoplastic, and posterior communicating artery was patent. Intraoperative proximal test occlusion at cervical internal carotid artery under neurophysiological monitoring, instead of preoperative balloon test occlusion, was performed to assess whether low-flow bypass was sufficient. The monitoring was unchanged during test occlusion, and the aneurysm was successfully trapped without high-flow bypass. Neither ischemic lesion nor neurologic deficits were found postoperatively.

CONCLUSIONS

Intraoperative proximal test occlusion is useful to decide on the surgical procedure of revascularization in patients with unclippable internal carotid aneurysm.

Proximal Middle Cerebral Artery Aneurysms: Microsurgical Management and Therapeutic Results

BACKGROUND

Management of proximal (M1) middle cerebral artery (MCA) aneurysms can be challenging. Because of the diversity of aneurysm morphology and location of M1 aneurysms, the surgical strategy should be tailored to each individual case, especially for complex cases. We assessed the safety and efficacy of an algorithmic strategy for the management of M1 aneurysms.

METHODS

A prospective single-center study of M1 aneurysms treated with microsurgery was performed. Our algorithmic strategy was determined by the location and complexity (e.g., size, shape) of the aneurysms. The surgical modalities included neck clipping, aneurysm resection and/or trapping, and proximal occlusion with revascularization. The clinical and radiographic data were analyzed.

RESULTS

From January 2007 to March 2017, 92 proximal MCA aneurysms in 92 patients were treated microsurgically. Aneurysm treatment techniques included clipping in 55, proximal occlusion in 21, aneurysm resection in 11, and trapping in 4. Bypass techniques included 2 anterior temporal artery reconstructions, 5 middle cerebral bifurcation reconstructions, 4 parent artery reanastomoses, 2 interpositional bypasses, 25 high-flow bypasses, and 7 medium-flow bypasses. Overall, good outcomes (modified Rankin scale score, 0-2) were seen in 49 of 92 patients (53.3%) at discharge and in 79 of 91 (86.8%) at the last follow-up visit. On the latest angiogram, 78 of 90 aneurysms (86.7%) had been completely occluded without a remnant. Bypass patency was confirmed in 38 of 43 bypass procedures.

CONCLUSIONS

Our present treating strategy might provide a benefit for patients with proximal MCA aneurysms.

Cerebral revascularization for the management of complex intracranial aneurysms: a single-center experience

OBJECTIVE

Because simple intracranial aneurysms (IAs) are increasingly treated endovascularly, neurovascular surgery has become focused on complex IAs that may require deconstructive aneurysm therapy with concomitant surgical bypass. The authors describe the decision-making process concerning cerebral revascularization and present outcomes that were achieved in a large case series of complex IAs managed with cerebral revascularization and parent artery occlusion.

METHODS

The authors retrospectively reviewed the medical records, including neuroimaging studies, operative reports, and follow-up clinic notes, of all patients who were treated at the National Brain Aneurysm Center between July 1997 and June 2015 using cerebral revascularization as part of the management of an IA. They recorded the location, rupture status, and size of each IA, as well as neurological outcome using the modified Rankin Scale (mRS), aneurysm and bypass status at follow-up, and morbidity and mortality.

RESULTS

The authors identified 126 patients who underwent revascularization surgery for 126 complex, atheromatous, calcified, or previously coiled aneurysms. Ninety-seven lesions (77.0%) were unruptured, and 99 (78.6%) were located in the anterior circulation. Aneurysm size was giant (≥ 25 mm) in 101 patients, large (10-24 mm) in 9, and small (≤ 9 mm) in 16 patients. Eighty-four low-flow bypasses were performed in 83 patients (65.9%). High-flow bypass was performed in 32 patients (25.4%). Eleven patients (8.7%) underwent in situ or intracranial-intracranial bypasses. Major morbidity (mRS score 4 or 5) occurred in 2 (2.4%) low-flow cases and 3 (9.1%) high-flow cases. Mortality occurred in 2 (2.4%) low-flow cases and 2 (6.1%) high-flow cases. At the 12-month follow-up, 83 (98.8%) low-flow and 30 (93.8%) high-flow bypasses were patent. Seventy-five patients (90.4%) undergoing low-flow and 28 (84.8%) high-flow bypasses had an mRS score ≤ 2. There were no statistically significant differences in patency rates or complications between low- and high-flow bypasses.

CONCLUSIONS

When treating challenging and complex IAs, incorporating revascularization strategies into the surgical repertoire may contribute to achieving favorable outcomes. In our series, low-flow bypass combined with isolated proximal or distal parent artery occlusion was associated with a low rate of ischemic complications while providing good long-term aneurysm control, potentially supporting its wider utilization in this setting. The authors suggest that consideration should be given to managing complex IAs at high-volume centers that offer a multidisciplinary team approach and the full spectrum of surgical and endovascular treatment options to optimize patient outcomes.

Rationale for graft selection in patients with complex internal carotid artery aneurysms treated with extracranial to intracranial high-flow bypass and therapeutic internal carotid artery occlusion

OBJECTIVE After internal carotid artery (ICA) sacrifice without revascularization for complex aneurysms, ischemic complications can occur. In addition, hemodynamic alterations in the circle of Willis create conditions conducive to the formation of de novo aneurysms or the enlargement of existing untreated aneurysms. Therefore, the revascularization technique remains indispensable. Because vessel sizes and the development of collateral circulation are different in each patient, the ideal graft size to prevent low flow-related ischemic complications (LRICs) in external carotid artery (ECA)-middle cerebral artery (MCA) bypass with therapeutic ICA occlusion (ICAO) has not been well established. Authors of this study hypothesized that the adequate graft size could be calculated from the size of the sacrificed ICA and the values of MCA pressure (MCAP) and undertook an investigation in patients with complex ICA aneurysms treated with ECA-graft-MCA bypass and therapeutic ICAO. METHODS In the period between July 2006 and January 2016, 80 patients with complex ICA aneurysms were treated with ECA-MCA bypass and therapeutic ICAO. Preoperative balloon test occlusion (BTO) was performed, and the BTO pressure ratio was defined as the mean stump pressure/mean preocclusion pressure. Low flow-related ischemic complications were defined as new postoperative neurological deficits and ipsilateral cerebral blood flow reduction. Initial MCAP (iMCAP), MCAP after clamping the ICA (cMCAP), and MCAP after releasing the graft (gMCAP) were intraoperatively monitored. The MCAP ratio was defined as gMCAP/iMCAP. Based on the Hagen-Poiseuille law, the expected MCAP ratio ([expected gMCAP]/iMCAP) was hypothesized as follows: (1 - cMCAP/iMCAP)(graft radius/ICA radius)² + (cMCAP/iMCAP). Correlations between the BTO pressure ratio and cMCAP/iMCAP, and between the actual and expected MCAP ratios, were evaluated. Risk factors for LRICs were also evaluated. RESULTS The mean BTO pressure ratio was significantly correlated with the mean cMCAP/iMCAP (r = 0.68, p < 0.0001). The actual MCAP ratio correlated with the expected MCAP ratio (r = 0.43, p < 0.0001). If the expected MCAP ratio was set up using the BTO pressure ratio instead of cMCAP/iMCAP (BTO-expected MCAP ratio), the mean BTO-expected MCAP ratio significantly correlated with the expected MCAP ratio (r = 0.95, p < 0.0001). During a median follow-up period of 26.1 months, LRICs were observed in 9 patients (11%). An actual MCAP ratio < 0.80 (p = 0.003), expected MCAP ratio < 0.80 (p = 0.001), and (M₂ radius/graft radius)² < 0.49 (p = 0.002) were related to LRICs according to the Cox proportional-hazards model. CONCLUSIONS Data in the present study indicated that it was important to use an adequate graft to achieve a sufficient MCAP ratio in order to avoid LRICs and that the adequate graft size could be evaluated based on a formula in patients with complex ICA aneurysms treated with ICAO.

Awake High-Flow Extracranial to Intracranial Bypass for Complex Cerebral Aneurysms: Institutional Clinical Trial Results

OBJECTIVE

Assess the potential added benefit to patient outcomes of "awake" neurological testing when compared with standard neurophysiologic testing performed under general endotracheal anesthesia.

METHODS

Prospective study of 30 consecutive adult patients who underwent awake high flow extracranial to intracranial (HFEC-IC) bypass. Clinical neurological and neurophysiologic findings were recorded. Primary outcome measures were the incidence of stroke/cerebrovascular accident (CVA), length of stay, discharge to rehabilitation, 30-day modified Rankin scale score, and death. An analysis was also performed of a retrospective control cohort (n = 110 patients who underwent HFEC-IC for internal carotid artery (ICA) aneurysms under standard general endotracheal anesthesia).

RESULTS

Five patients (16.6%) developed clinical awake neurological changes (4, contralateral hemiparesis; 1, ipsilateral visual changes) during the 10-minute ICA occlusion test. These patients had 2 kinks in the graft, 1 vasospasm, 1 requiring reconstruction of the distal anastomosis, and 1 developed blurring of vision that reversed after the removal of the distal permanent clip on the ICA. Three of these 5 patients had asynchronous clinical "awake" neurological and neurophysiologic changes. Two patients (7%) developed CVA. Median length of stay was 4 days. Twenty-eight of 30 patients were discharged to home. Median modified Rankin scale score was 1. There were no deaths in this series. Absolute risk reduction in the awake craniotomy group (n = 30) relative to control retrospective group (n = 110) was 7% for CVA, 9% for discharge to rehabilitation, and 10% for graft patency.

CONCLUSIONS

Temporary ICA occlusion during HFEC-IC bypass for ICA aneurysms in conjunction with awake intraoperative clinical testing was effective in detecting a subset of patients (n = 3, 10%) in whom neurological deficit was not detected by neurophysiologic monitoring alone.

Treatment of complex intracranial aneurysm: Case report of the simultaneous use of endovascular and microsurgical techniques

Background:

The surgical treatment of complex intracranial aneurysms (CIAs) represents a significant challenge to the skill and expertise of the neurosurgeon. The natural history of complex cerebrovascular lesions is especially unfavorable because of the pressure effect on adjacent areas, the risk of embolism in the presence of intraluminal thrombi, and the possibility of hemorrhage through leakage or rupture of the aneurysm. The surgical strategy must be customized for each case in order to maximize the treatment effectiveness and the safety of the patient.

Case Description:

A 68-year-old woman presented with a 10-month history of atypical headaches but no other neurological symptoms. Computed tomography scan and digital subtraction angiography revealed an unruptured saccular aneurysm on the M1 segment of the right middle cerebral artery. The lesion was 21 mm in length in its largest diameter and with an undefined neck (extensive involvement of the walls of the afferent vessel). Craniotomy was performed in order to expose the lesion and allow microsurgical dissection of the neck of the aneurysm and its adjacent structures. A balloon catheter was navigated via the internal carotid artery to a position alongside the aneurysm neck. With the balloon fully inflated, the aneurysm was punctured and drained, and a guide clip was located at the neck of the aneurysm. Additional clips were applied using a similar procedure to ensure the exclusion of the aneurysm.

Conclusion:

The patient recovered without complications and complete occlusion of the CIA was confirmed on follow-up angiography. A modified Rankin score of 0 was attributed to the patient 6 months after treatment. A multidisciplinary perspective is important in planning and executing the treatment of CIAs.

Coiling of a Ruptured Large Internal Carotid Artery Aneurysm via Extracranial-Intracranial Saphenous Vein Bypass Graft Just After Proximal Ligation of the Internal Carotid Artery

BACKGROUND

Combined direct and endovascular surgery has been performed to treat large to giant internal carotid artery (ICA) aneurysms. This report describes successful treatment of a large ICA aneurysm by coiling of the aneurysm via an extracranial-intracranial saphenous vein (SV) graft just after bypass and ICA proximal ligation.

CASE DESCRIPTION

A 66-year-old woman presented with a left ICA supraclinoid aneurysm with progressive visual field defect and impaired visual acuity in the left eye. While waiting for scheduled surgery, she experienced a subarachnoid hemorrhage. An extracranial-intracranial high-flow bypass using an SV graft and proximal ligation of the ICA were performed. Coiling of the aneurysm was immediately performed successfully via the SV bypass graft. The patient experienced no new neurologic deficit after this treatment. Follow-up radiologic evaluations using magnetic resonance imaging and magnetic resonance angiography revealed complete aneurysm occlusion.

CONCLUSIONS

Aneurysm coiling via an extracranial-intracranial SV bypass graft could offer an alternative when an antegrade access route to the ICA is not used because of prior parent artery ligation.

Open and endovascular repair of aneurysms affecting the distal extracranial internal carotid artery: case series

Objective:

Three cases of internal carotid artery aneurysm affecting the distal cervical segment were retrospectively reviewed.

Methods:

Two patients underwent open surgical repair requiring petrous segment exposure for bypass of the affected segment using a Fisch type A lateral skull base approach. The third patient underwent endovascular stenting.

Results:

There were no cerebrovascular complications post-operatively. Both open repair patients experienced temporary lower cranial nerve palsies. One required facial nerve grafting. All patients had patent grafts at follow up. The stent graft patient had a small endoleak at six months.

Conclusion:

Endovascular and open approaches both have advantages and disadvantages. Treatment needs to be tailored to the lesion and the patient. An open surgical approach is difficult but well established. Endovascular treatment of these lesions is a relatively recent technique, and new cases need to be continually reported with a view to attaining long-term data.

Application of intraoperative motor evoked potential monitoring during giant internal carotid artery aneurysm surgery using prolonged temporary occlusion

BACKGROUND

Clipping and bypass surgery are common therapeutic options for the management of giant internal carotid artery (ICA) aneurysms. However, potential ischemic risks may be exaggerated by prolonged temporary occlusion (PTO) during the surgery. Monitoring motor-evoked potentials (MEPs) is a sensitive technique for detecting potential ischemia intraoperatively. This preliminary study was designed to evaluate the effectiveness of applying MEP monitoring during giant ICA aneurysm surgery using PTO.

METHODS

From July 2009 to July 2012, 11 patients with giant ICA aneurysms who could not pass the preoperative hemodynamic evaluations were enrolled in this study. MEP monitoring was utilized intraoperatively in all cases. Clipping was performed if there were no significant MEP changes under PTO. A variant extracranial-to-intracranial (EC-IC) bypass was performed if there was reproducible loss of MEP signals after PTO or unclippable anatomic features.

RESULTS

Five patients underwent clipping alone and six underwent bypass. There were no significant differences in baseline clinical data between the two groups. The overall percentage of patients with good outcomes (Glasgow Outcome Score ≥4) improved from 72.7 % (8/11) postoperatively to 90.9 % (10/11) after 26.0 ± 9.5 months of follow-up. There were no significant differences between the clipping and bypass groups regarding short- and long-term outcomes (p = 0.545 and p = 1.000).

CONCLUSIONS

MEP monitoring is useful for evaluating the safety of PTO, surgical strategy, and outcomes of giant ICA aneurysm surgery. Direct clipping during safe PTO under intraoperative MEP monitoring is applicable for giant ICA aneurysms. Its use achieved favorable outcomes by indicating the need for bypass surgery.

Donor Selection in Flow Replacement Bypass Surgery for Cerebral Aneurysms: Quantitative Analysis of Long-term Native Donor Flow Sufficiency

BACKGROUND:

Graft selection in extracranial-intracranial bypass surgery for cerebral aneurysms has traditionally been based on clinical impression and operator preference. However, decision making can be optimized with a donor selection algorithm based on intraoperative flow data.

OBJECTIVE:

To present long-term follow-up and quantitative assessment of flow sufficiency for native donors selected in this manner.

METHODS:

Patients with bypass for anterior circulation intracranial aneurysms using only a native donor (superficial temporal artery) selected on the basis of an intraoperative flow algorithm over a 10-year period were retrospectively studied. Intracranial hemispheric and bypass flows were assessed preoperatively and postoperatively when available with quantitative magnetic resonance angiography.

RESULTS:

Twenty-two patients with flow data were included (median aneurysm size, 22 mm). The intraoperative flow offer (cut flow) of the superficial temporal artery was sufficient in these cases relative to the flow demand in the sacrificed vessel (59 vs 28 mL/min) to warrant its use. Bypass flow averaged 81 mL/min postoperatively (n = 19). Bypass flows were highest in the immediate postoperative period but remained stable between the intermediate and final follow-up (40 vs 52 mL/min; P = .39; n = 8). Mean ipsilateral hemisphere flows were maintained after bypass (299 vs 335 mL/min; P = .42; n = 7), and remained stable over intermediate and long-term follow-up. Ipsilateral hemispheric flows remained similar to contralateral flows at all time points.

CONCLUSION:

Despite a relative reduction in bypass flow over time, hemispheric flows were maintained, indicating that simple native donors can carry sufficient flow for territory demand long term when an intraoperative flow-based algorithm is used for donor selection.

Extracranial to intracranial by-pass anastomosis: Review of our preliminary experience from a low volume center in Egypt

Background:

Cerebral revascularization is a useful microsurgical technique for the treatment of steno-occlusive intracranial ischemic disease, complex intracranial aneurysms that require deliberate occlusion of a parent artery and invasive skull base tumors. We describe our preliminary experience with extracranial-to-intracranial by-passes at a low volume center; and discuss clinical indications and microsurgical techniques, challenges in comparison to large advanced referral centers.

Materials and Methods:

Twenty-seven patients with hemodynamic ischemia or complex aneurysms or skull base tumors were operated at Cairo University Hospitals in the period between May 2009 and June 2014. All patients operated by a low flow by-pass were operated through a superficial temporal artery to middle cerebral artery (MCA) anastomosis. All patients chosen for a high flow by-pass were operated using a radial artery graft interposed between the MCAs distally and the common or the external carotid artery proximally. Patency was confirmed at the end of surgery using appearance on the table and confirmed after surgery by transcranial color-coded duplex or computed tomography angiography. All patient data were prospectively collected and retrospectively analyzed at the end of surgery.

Results:

Nineteen patients (70.4%) were operated upon for flow augmentation and eight patients (29.6%) were operated upon for flow replacement. A total of 30 anastomoses were performed. All except one were patent which gives a patency rate of 96.3%. There was one death in the present series resulting from a hyperperfusion syndrome. 89.5% of patients with hemodynamic ischemia stopped having symptoms after surgery. All but one patient operated for hemodynamic ischemia showed a considerable cognitive improvement after surgery. None of the patients operated upon for flow replacement showed improvement of oculomotor nerve function in spite of adequate intraoperative decompression. All patients treated for flow replacement showed the absence of recurrence on follow-up.

Conclusion:

Our initial results for both low and high flow by-pass procedures in our low volume center indicate that such complex surgical procedures are possible with results comparable to those obtained in other larger referral centers throughout the world. This procedure not only represents a more definitive treatment when compared to other endovascular or radiation treatments but is also much less costly when compared to other treatment modalities.

Rescue Bypass for Revascularization After Ischemic Complications in the Treatment of Giant or Complex Intracranial Aneurysms

BACKGROUND

Surgical trapping or endovascular deconstruction commonly is used for the treatment of giant or complex intracranial aneurysms. Preoperative balloon test occlusion and cerebral blood flow studies and intraoperative neurophysiologic monitoring can indicate whether sufficient collateralization exists or whether revascularization is needed. Hemodynamic insufficiency can occur, however, despite passing these tests, necessitating posttreatment revascularization.

METHODS

We conducted a retrospective review of patients who underwent surgical or endovascular parent vessel occlusion for the management of giant or complex intracranial aneurysms and subsequently required rescue bypass for symptoms of hemodynamic insufficiency. Pre- and postrevascularization functional status was measured with the modified Rankin Scale.

RESULTS

During a 15-year period from 1997 to 2012, a rescue bypass was performed in 5 patients each harboring a giant or complex intracranial internal carotid artery (ICA) aneurysm that was treated with surgical trapping or endovascular deconstruction in a previous procedure. All bypasses were extracranial-to-intracranial and included cervical ICA to middle cerebral artery, subclavian to middle cerebral artery, and cervical ICA to supraclinoid ICA anastomoses via either a saphenous vein or radial artery graft. Functional outcome at time of last follow-up was improved in each patient (improvement in modified Rankin Scale of 1-3 points).

CONCLUSIONS

Ischemic complications must always be anticipated in the treatment of giant or complex intracranial aneurysms, even if pre- and intraoperative blood flow studies indicate sufficient collateralization. Here we show that extracranial-to-intracranial bypass is an effective option to rescue unanticipated hemodynamic insufficiency after parent vessel occlusion. This study emphasizes the need for cerebrovascular surgeons to maintain proficiency in complex bypass techniques.

Prevention of Retrograde Blood Flow Into Large or Giant Internal Carotid Artery Aneurysms by Endovascular Coil Embolization with High-Flow Bypass: Surgical Technique and Long-Term Results

BACKGROUND

Recanalization has been reported in large or giant aneurysms of the internal carotid artery (ICA) addressed by high-flow bypass and endovascular treatment. Aneurysmal recanalization may be attributable to retrograde blood flow into the aneurysm through the ICA branches, such as the ophthalmic artery or the meningohypophyseal trunk, or through the surgically created bypass. We modified the endovascular treatment of aneurysms to prevent retrograde flow and evaluated the long-term efficacy of our method.

METHODS

We used a hybrid operative/endovascular technique to treat 5 patients with large or giant aneurysms arising from the C2-C4 segment of the ICA who presented with visual symptoms due to the mass effect of the aneurysm. To prevent retrograde flow into the aneurysm our modified endovascular treatment involves coil embolization of the aneurysmal orifice and the ICA, including the origin of the ophthalmic artery and meningohypophyseal trunk, and placement of a high-flow bypass using a radial artery graft.

RESULTS

During the 5- to 12-year follow-up period, 4 aneurysms disappeared, and the other decreased in size. There were no subarachnoid hemorrhages. All bypass grafts remained patent. Visual preservation was achieved in 2 patients; 1 patient manifested visual improvement. Although 2 patients experienced transient neurological deficits we encountered no permanent complications in this series. The final modified Rankin scale of the 5 patients was 0 or 1.

CONCLUSIONS

Prevention of retrograde flow into the aneurysm by coil embolization with high-flow bypass is a safe and effective method. It prevents the recanalization of large or giant ICA aneurysms.

Technical failure of giant supraclinoid aneurysm after internal carotid artery occlusion. A report of three cases

We describe three cases of technical failure in patients with giant supraclinoid aneurysm treated with internal carotid artery (ICA) occlusion. Case 1 was a 65-year-old woman who presented with a two-month history of headache accompanied by blurred vision of the left eye. Case 2 was a 43-year-old woman who presented with a six-month history of headache accompanied by blurred vision of the right eye. Case 3 was a 21-year-old man admitted due to headache and blurred vision of the left eye, accompanied by left oculomotor nerve palsy for three months. Cerebral angiography revealed giant supraclinoid aneurysms in these patients. All of them were treated with ICA occlusion. One case had recurrent headache symptoms after the first procedure and was retreated. Two cases suffered from post-procedural intracranial hemorrhagic complications. Before ICA occlusion for giant supraclinoid aneurysm, balloon occlusion test was used to evaluate the collateral anastomosis between the external carotid artery (ECA) and the ICA, and still plays an important role in preventing treatment failure.

Technical Failure of Giant Supraclinoid Aneurysm after Internal Carotid Artery Occlusion

We describe three cases of technical failure in patients with giant supraclinoid aneurysm treated with internal carotid artery (ICA) occlusion.

Case 1 was a 65-year-old woman who presented with a two-month history of headache accompanied by blurred vision of the left eye. Case 2 was a 43-year-old woman who presented with a six-month history of headache accompanied by blurred vision of the right eye. Case 3 was a 21-year-old man admitted due to headache and blurred vision of the left eye, accompanied by left oculomotor nerve palsy for three months. Cerebral angiography revealed giant supraclinoid aneurysms in these patients. All of them were treated with ICA occlusion.

One case had recurrent headache symptoms after the first procedure and was retreated. Two cases suffered from post-procedural intracranial hemorrhagic complications.

Before ICA occlusion for giant supraclinoid aneurysm, balloon occlusion test was used to evaluate the collateral anastomosis between the external carotid artery (ECA) and the ICA, and still plays an important role in preventing treatment failure.

EC-IC bypass for cavernous carotid aneurysms: An initial experience with twelve patients

AIMS

Need for performing a bypass procedure prior to parent artery occlusion in patients with good cerebral vascular reserve is controversial. We analyze our experience of 12 giant internal carotid artery aneurysms treated with extracranial-intracranial (EC-IC) bypass and proximal artery occlusion.

MATERIALS AND METHODS

Retrospective analysis of the case records of all complex carotid aneurysms operated in our institute since January 2009.

RESULTS

The study included eleven cavernous carotid aneurysms and one large fusiform cervical carotid aneurysm reaching the skull base. Preoperative assessment of cerebral vascular reserve was limited to Balloon test occlusion with hypotensive challenge. Eleven patients who successfully completed a Balloon test occlusion (BTO) underwent low flow superficial temporal artery to middle cerebral artery (STA-MCA) bypass, while one patient with a failed BTO underwent a high flow bypass using a saphenous vein graft. Parent artery ligation was performed in all patients following the bypass procedure. Check angiogram revealed thrombosis of the aneurysm in all patients with a graft patency rate of 81.8%. We had one operative mortality, probably related to a leak from the anastomotic site. The only patient who had a high flow bypass developed contralateral hemispheric infarcts and remained vegetative. All the other patients had a good recovery and with a Glasgow outcome score of 5 at last follow-up.

CONCLUSION

We feel that combining EC-IC bypass prior to parent vessel occlusion helps in reducing the risk of post operative ischemic complications especially in situations where a complete mandated cerebral blood flow studies are not feasible.

Surgical strategies for aneurysms deemed unclippable and uncoilable

Although most cerebral aneurysms can nowadays be successfully treated either by standard clipping or sole coiling, a subset of aneurysms may not be amenable to standard clipping or coiling and require alternative treatment options. Surgical options, other than clipping and/or endovascular options other than sole coiling, may be the optimal treatment plan for some complex aneurysms. Surgical strategies for such complex aneurysms include parent artery occlusion, revascularization procedures and flow redirection. In this article, we review which factors are predictive of failure of conventional aneurysm treatment options; summarize key information needed to orient treatment decision; and discuss surgical options for unclippable and uncoilable aneurysms.