Microvascular Doppler Ultrasonography Research Articles

Use of intraoperative microvascular Doppler during subinguinal microsurgical varicocelectomy in children reduces complications.

This study assessed the impact of intraoperative microvascular Doppler ultrasonography (MDU) during microsurgical subinguinal varicocele correction in children. Nineteen patients who underwent intraoperative MDU during subinguinal microsurgical varicocelectomy between 2021 and 2023 were included in this study. Each patient's age, varicocele side, clinical examination findings, preoperative ultrasonography results, intraoperative findings, spermatic artery counts and findings in terms of MDU use, postoperative complications, and results were evaluated. All varicoceles were on the left side and the average age of the patients was 15.2 years. The indications for varicocelectomy were testicular hypotrophy (n = 10) and scrotal pain or fullness (n = 9). When a surgical microscope was used, testicular artery pulsation was detected in only five patients, whereas it was detected in all cases when MDU was used. In 16 cases, a single testicular artery was identified, and two arteries were identified in three cases. Additionally, in a case where a spermatic vein was suspected, it was not ligated due to the detection of pulsation with an arterial pattern using MDU. Two to three lymphatic channels were isolated and preserved, an average of 7.5 vessels were ligated, and five external spermatic veins were identified and ligated. There were no complications, and six of the patients with testicular hypotrophy showed signs of the catch-up growth phenomenon. The use of MDU during subinguinal microsurgical varicocelectomy in children not only increases the success rate but also minimizes complications such as hydrocele and recurrence.

Intraoperative Hemodynamics of Parasylvian Cortical Arteries for Predicting Postoperative Symptomatic Cerebral Hyperperfusion after Direct Revascularization in Patients with Moyamoya Disease: A Preliminary Study.

Objective. The search for methods by which to predict the risks of cerebral hyperperfusion syn-drome (CHS) in adults with moyamoya disease (MMD), including those utilizing new biomarkers, still deserves further research. The objective of this study was to investigate the association between the hemodynamics of parasylvian cortical arteries (PSCAs) and postoperative CHS. Methods. A consecutive number of adults with MMD who had undergone direct bypass between September 2020 and December 2022 were recruited. Intraoperative microvascular doppler ultrasonography (MDU) was performed to evaluate the hemodynamics of PSCAs. The intraoperative flow direction, mean value of velocity (MVV) of recipient artery (RA) and bypass graft were recorded. According to flow direction after bypass, RA was divided into entering sylvian (RA.ES) and leaving sylvian (RA.LS) subtypes. Univariate, multivariate, and ROC analyses of the risk factors for postoperative CHS were performed. Results. A total of 16 (15.09%) cases in 106 consecutive hemispheres (101 patients) sat-isfied the postoperative CHS criteria. According to univariate analysis, advanced Suzuki stage, MVV of RA before bypass, and fold increase of MVV in RA.ES after bypass were significantly associated with postoperative CHS (p < 0.05). Multivariate analysis indicated that left-operated hemisphere (OR (95%CI), 4.58 (1.05-19.97), p = 0.043), advanced Suzuki stage (OR (95%CI), 5.47 (1.99-15.05), p = 0.017), and fold increase of MVV in RA.ES (OR (95%CI), 1.17 (1.06-1.30), p = 0.003) were statistically significantly associated with the occurrence of CHS. The cut-off value of fold increase of MVV in RA.ES was 2.7-fold (p < 0.05). Conclusions. Left-operated hemisphere, advanced Suzuki stage, and postoperative fold increase of MVV in RA.ES were potential risk factors for postoperative CHS. Intraoperative MDU was useful for evaluating hemodynamics and predicting CHS.

Microvascular Doppler ultrasound in children with acute pyelonephritis

To compare the diagnostic performance of microvascular Doppler ultrasonography (MVUS) to B-mode and con-ventional colour Doppler US (CDUS) for detecting acute pyelonephritis (APN) lesions in children. An IRB-approved retrospective study was performed. From July 2018 to January 2019, 41 APN lesions in 28 children (15 boys, 13 girls; age range, 1-196 months; mean age, 53 months) who underwent 99mTc‒dimercaptosuccinic acid renal scintig-raphy (DMSA) or contrast-enhanced computed tomography (CECT) and US including B-mode, CDUS, and MVUS were enrolled in this study. Three paediatric radiologists independently reviewed the B-mode, CDUS and MVUS images for the DMSA or CECT-proven APN lesions and evaluated the lesion visibility, lesion distinguishability and diagnostic confidence between the MVUS and CDUS images. A total 41 of APN lesions were verified by DMSA (41 lesions) or CECT (3 lesions) during the same hospitalization period with renal US. Among 41 APN lesions, 52.8% was visible on B-mode, 85.4% on CDUS, and 94.3% on MVUS (p<0.001). Comparing the extent and margins of the lesions, MVUS had better results than CDUS in 41.5% of the lesions, CDUS had better results in 6.5% and they were equal in 52% (p<0.001). The diagnostic con-fidence of the APN lesions was higher for MVUS than CDUS in 36.6%, higher for CDUS than MVUS in 4.9%, and equal in the remaining 58.5% (p<0.05). The interobserver agreement was fair to moderate. MVUS showed improved detectability of hypoperfused areas in paediatric APN and provided higher diagnostic confidence.

Comparison of 3D intraoperative digital subtraction angiography and intraoperative indocyanine green video angiography during intracranial aneurysm surgery.

During the last decade, improvements in real-time, high-resolution imaging of surgically exposed cerebral vasculature have been realized with the successful introduction of intraoperative indocyanine green video angiography (ICGVA) and technical advances in intraoperative digital subtraction angiography (DSA). With the availability of 3D intraoperative DSA (3D-iDSA) in hybrid operating rooms, the present study offers a contemporary comparison for rates of accuracy and discordance. In this retrospective study of prospectively collected data, 140 consecutive patients underwent microsurgical treatment of intracranial aneurysms (IAs) in a hybrid operating room. Variables analyzed included patient demographics, aneurysm-specific characteristics, intraoperative ICGVA and 3D-iDSA findings, and the need for intraoperative clip readjustment. The authors defined the discordance rate of the two modalities as a false-negative finding that necessitated clip repositioning after 3D-iDSA. In 120 patients, ICGVA and 3D-iDSA were used to evaluate 134 IA obliterations. Of 215 clips used, 29 (14%) were repositioned intraoperatively, improving the surgical result in all 29 patients (24%). Repositioning was prompted by visual inspection and microvascular Doppler ultrasonography in 8 (28%), ICGVA in 13 (45%), and 3D-iDSA in 7 (24%) patients. Clip repositioning was needed in 7 patients (6%) based on 3D-iDSA, yielding an ICGVA accuracy rate of 94%. Five (71%) of the ICGVA-3D-iDSA discordances that prompted clip repositioning occurred at the anterior communicating artery complex. A combination of vascular monitoring techniques most often achieved correct intraoperative interpretation of complete IA occlusion and parent artery integrity. Compared with 3D-iDSA imaging, ICGVA demonstrated high accuracy. Despite the relatively low discordance rate, iDSA was confirmed to be the gold standard. Improved imaging quality, including 3D-iDSA, supports its routine use in IA surgery, obviating the need for postoperative DSA.

The Special Considerations in the Surgical Management of Proximal Anterior Cerebral Artery Aneurysms

Proximal anterior cerebral artery (A1) aneurysms are difficult to clip because of their frequent proximity to perforators, location behind the parent artery, or adherence to surrounding structures. We retrospectively reviewed a consecutive series of patients with A1 aneurysms and report the clinical status, radiologic findings, treatment methods, and outcome. This series included 19 male and 12 female patients with a mean age of 50 years. The morphology of the A1 aneurysms was fusiform in 2 patients and saccular in the remaining 29 patients. Multiple aneurysms were presented in 9 patients (29.0%). On admission, 26 patients (83.9%) presented with subarachnoid hemorrhage, 3 of whom had an additional intracerebral hematoma. All surgeries were performed with a standard pteriomal craniotomy. The mean Glasgow Outcome Scale score at final follow-up was 4.8 (interquartile range, 5, 5), with 26 patients (83.9%) rated as 5. The mean follow-up time was 38.5 months (range, 12-60 months). A1 aneurysms are rare but have their own complex characteristics and are difficult to treat. Meticulous analysis of the relevant angiographs is needed for their diagnosis. An important consideration in surgery is the preservation of perforators and prevention of rupture. Wide opening of the sylvian fissure and temporary control of the parent artery can facilitate dissection of the A1 aneurysms dome. Multiple intraoperative monitoring methods, such as microvascular Doppler ultrasonography and somatosensory and motor evoked potential monitoring, can reduce the relevant complications of surgery.

Application of microvascular Doppler ultrasonography in microsurgical varicocelectomy

From January 2015 to June 2016, 107 patients with varicocele underwent microsurgical varicocelectomy in the First Affiliated Hospital of Xiamen University. The clinical outcomes of microsurgical varicocelectomy with (n=56) or without (n=51) microvascular Doppler ultrasonography were compared. All patients were treated successfully by both methods and no postoperative complications such as testicular atrophy and/or hydrocele were found during 12 months postoperative follow-up. For the group without microvascular Doppler, accidental artery ligation occurred in 2 cases and the internal spermatic vessels were unidentifiable in 4 cases, and recurrence occurred in one case. By contrast, no artery injury or ligation occurred during the operation with microvascular Doppler, and no recurrence occurred postoperatively. Microvascular Doppler ultrasonography, which is reliable for discerning arteries and veins, can effectively and safely assist microsurgical varicocelectomy for treatment of varicocele. Key words: Varicocele; Ligation; Microscopy, acoustic

Concomitant unruptured intracranial aneurysms and ischemic cerebrovascular diseases: a surgical experience of 31 cases

Objective: To summarize the clinic experience of preventing cerebral ischemic events during perioperative period in patients which concomitant unruptured intracranial aneurysms and ischemic cerebrovascular diseases. Methods: The clinical materials of 31 consecutive patients with concomitant unruptured intracranial aneurysms and ischemic cerebrovascular diseases from April 2010 to April 2014 were retrospectively reviewed.A total of 35 aneurysms were detected, and all of them were unruptured aneurysms.Among them, 17 cases were located on the ipsilateral side of artery stenosis or occlusion, and 18 cases were detected in the contralateral side. Minimal invasive surgical approaches such as small pterional approach and lateral sub-frontal approach were adopted.The better management of perioperative blood pressure was performed. Intraoperative electroencephalogram and somatosensory evoked potential monitoring, indocyanine green video angiography and/or microvascular Doppler ultrasonography were regularly used to guarantee the safety of the surgery. The follow-up by digital subtraction angiography or computed tomography angiography were made. Results: All of 35 aneurysms were clipped. Major infarction occurred in one patient with posterior communicating artery aneurysm concomitant with common cervical carotid artery stenosis.Large bone flap was resected and dural-matter were got enlarged to tolerate the edema period.Paralysis and aphasia accompanied at discharge.Minor infarction in posterior limb of internal capsule occurred in one patient.Twenty-nine patients were favorable with Glasgow Outcome Scale (GOS) score 5 at discharge, one patient with minor neurological defect (GOS 4), and one patient with severe neurological defect (GOS 3). The follow-up period was 6 to 40 months.Four patients were lost.The modified Rankin scale (MRS) of last follow-up were 0-1 in 25 patients, 2 in one patient and 3 in one patient.Third months after operation, 3 cases were performed carotid artery stenosis, 1 patients were performed carotid endarterectomy. Conclusion: Reinforcing the management of perioperative blood pressure, adjusting the perioperative blood coagulation function, and combine application of intraoperative monitoring technology can effectively prevent the occurrence of cerebral ischemia.

Early retreatment after surgical clipping of ruptured intracranial aneurysms.

Although a rerupture after surgical clipping of ruptured intracranial aneurysms is rare, it is associated with high morbidity and mortality. The causes for retreatment and rupture after surgical clipping are not clearly defined. From a prospectively maintained database of 244 patients who had undergone surgical clipping of ruptured intracranial aneurysms, we selected patients who experienced retreatment or rerupture within 30days after surgical clipping. Aneurysm occlusions were examined by microvascular Doppler ultrasonography and indocyanine green video-angiography. Indications for retreatment included rerupture and partial occlusion. We analyzed the characteristics and causes of early retreatment. Six patients (2.5%, 95% CI 0.9 to 5.3%) were retreated within 30days after surgical clipping, including two patients (0.8%, 95% CI 0.1 to 2.9%) who experienced a rerupture. The retreated aneurysms were found in the anterior communicating artery (AcomA) (n=5) and basilar artery (n=1). Retreatment of the AcomA (7.5%) was performed significantly more frequently than that of other arteries (0.56%) (p<0.01). A laterally projected AcomA aneurysm (17.4%) was more frequently retreated than were other aneurysm types (2.3%). Cases of laterally projecting AcomA aneurysms tended to result from an incomplete clip placed using a pterional approach from the opposite side of the aneurysm projection. Despite developments, the rates of retreatment and rerupture after surgical clipping remain similar to those reported previously. Retreatment of the AcomA was significantly more frequent than was retreatment of other arteries. Patients underwent retreatment more frequently when they were originally treated for lateral type aneurysms using a pterional approach from the opposite side of the aneurysm projection. The treatment method and evaluation modalities should be considered carefully for AcomA aneurysms in particular.

A simple bracing technique to correct kinking of arterial branches to avoid ischemic sequelae during neurovascular surgery.

Background:During microscopic procedures for neurovascular disease, we sometimes encounter kinking of arterial branches resulting in ischemic sequelae. A simple and useful technique that involves inserting a small, ball-like prosthesis made of oxidized cellulose or shredded Teflon with fibrin glue that corrects the arterial branch kinking and avoids subsequent compromise is reported.Methods:Between January and December 2014, three patients developed arterial kinking during microscopic procedures, including two in the caudal loop of the posterior inferior cerebellar artery during microvascular decompression for glossopharyngeal neuralgia and one in a branch of the middle cerebral artery (MCA) during clipping for an unruptured MCA aneurysm. Blood flow insufficiency was confirmed by microvascular Doppler ultrasonography (MDU) and indocyanine green (ICG) videoangiography. The prosthesis, which was made of shredded Teflon in two cases and oxidized cellulose in one case, was inserted into the crotch of the kinked arteries to correct the kinking of the arteries and restore the proper vascular shape and normal blood flow.Results:The small, ball-shaped prosthesis corrected the kinked arteries and maintained the proper shape, which was confirmed by ICG videoangiography and MDU during the operation and three-dimensional computerized tomography angiography postoperatively. Postoperatively, the patients did not manifest any ischemic sequelae related to the kinked arteries.Conclusion:The insertion of prostheses with fibrin glue into the crotch of a kinked artery for repair is considered a simple and useful method for correcting a kinked artery that avoids ischemic sequelae.

Individualized surgical treatment of complex middle cerebral artery aneurysms

To summarize individualized surgical treatment strategies for complex middle cerebral artery (MCA) aneurysms. Twenty patients with complex MCA aneurysms treated by microsurgery in Chinese People's Liberation Army General Hospital between December 2009 and November 2012 were retrospectively analyzed. There were 12 male and 8 female patients, with a mean age of 43 years (range: 14-58 years). Giant aneurysms (size > 2.5 cm) were found in 6 cases, wide-neck aneurysms in 7 cases and serpentine ones in 3 patients. Important perforators were involved in aneurysm neck in 2 cases. Important branches originated from aneurysms in 6 patients. Two patients harbored recurrent aneurysms after coiling. Individualized surgical strategies were planned according to preoperative imaging. A frontotemporal approach was routinely used. Intraoperative somatosensory evoked potential monitoring, indocyanine green videoangiography and microvascular Doppler ultrasonography were regularly used. A postoperative digital subtraction angiography (DSA) or computed tomography angiography (CTA) was performed to verify the efficacy of treatment and patency of bypass vessels. Of the 20 cases, 7 aneurysms were clipped with clipping and reconstruction of parent artery with multiple clips, 3 M1 segment aneurysms were proximally occluded with extra-intracranial high-flow revascularization, 2 aneurysms were treated with aneurysmectomy with superficial temporal artery to middle cerebral artery low-flow revascularization, 1 aneurysm was treated with aneurysmectomy with superficial temporal artery to middle cerebral artery low-flow revascularization and branch side-to-side anastomosis, 2 aneurysms were treated with aneurysmectomy and re-anastomosis of parent artery, 1 aneurysm was treated with aneurysmectomy and re-anastomosis of parent artery and reinplantation of lenticulostriate artery, 3 bilateral MCA aneurysms were clipped by unilateral approach, and 1 was trapped. Nineteen patients were favorable with Glasgow Outcome Scale score 4-5 at discharge, and 1 patient died of cardiac infarction one week after surgery. The mean clinical follow-up was 20 months (range: 6-39 months). During follow-up, no bleeding occurred. DSA or CTA confirmed absence of aneurysm in 14 cases and residual neck in 2 patients. The other 3 patients were lost to follow-up. Individualized, multi-modality surgical treatment strategies are effective and safe solution for treatment of complex MCA aneurysms. Revascularization remains imperative surgical technique.

Essentials in intraoperative indocyanine green videoangiography assessment for intracranial aneurysm surgery: conclusions from 295 consecutively clipped aneurysms and review of the literature

Indocyanine green (ICG) videoangiography (VA) in cerebral aneurysm surgery allows confirmation of blood flow in parent, branching, and perforating vessels as well as assessment of remnant aneurysm parts after clip application. A retrospective analysis and review of the literature were conducted to determine the current essential advantages of ICG-VA in aneurysm surgery. The authors retrospectively evaluated all aneurysm cases treated with the aid of intraoperative ICG-VA at a single institution between 2007 and 2013. They also analyzed the literature published since the initial description of ICG-VA in 2003. Two hundred forty-six procedures were performed in 232 patients harboring 295 aneurysms. The patients, whose mean age was 54 years, consisted of 159 women and 73 men. One hundred twenty-four surgeries were performed after subarachnoid hemorrhage, and 122 were performed for incidental aneurysms. Single aneurysms were clipped in 185 patients, and multiple aneurysms were clipped in 47 (mean aneurysm diameter 6.9 mm, range 2-40 mm). No complications associated with ICG-VA occurred. Intraoperative microvascular Doppler ultrasonography was performed before ICG-VA in all patients, and postoperative digital subtraction angiography (DSA) studies were available in 121 patients (52.2%) for retrospective comparative analysis. In 22 (9%) of 246 procedures, the clip position was modified intraoperatively as a consequence of ICG-VA. Stenosis of the parent vessels (16 procedures) or occlusion of the perforators (6 procedures), not detected by micro-Doppler ultrasonography, were the most common problems demonstrated on ICG-VA. In another 11 procedures (4.5%), residual perfusion of the aneurysm was observed and one or more additional clips were applied. Vessel stenosis or a compromised perforating artery occurred independent of aneurysm location and was about equally common in middle cerebral artery and anterior communicating artery aneurysms. In 2 procedures (0.8%), aneurysm puncture revealed residual blood flow within the lesion, which had not been detected by the ICG-VA. In the postoperative DSA studies, unexpected small (< 2 mm) aneurysm neck remnants, which had not been detected on intraoperative ICG-VA, were found in 11 (9.1%) of 121 patients. However, these remnants remained without consequence except in 1 patient with a 6-mm residual aneurysm dome, which was subsequently embolized with coils. In a large cohort of consecutive patients, ICG-VA proved to be a helpful intraoperative tool and led to a significant intraoperative clip modification rate of 15%. However, small, < 2-mm-wide neck remnants and a 6-mm residual aneurysm were missed by intraoperative ICG-VA in up to 10% of patients. Results in this study confirm that DSA is indispensable for postoperative quality assessment in complex aneurysm surgery.

The clinical diagnosis and treatment of blood-blister-like cerebral aneurysms in supra-clinoid segment of internal carotid artery

To study the clinical characteristics, surgical principles and treatment options of blood-blister-like cerebral aneurysms in supra-clinoid segment of internal carotid artery. Twelve blood-blister-like aneurysms were retrospectively studied including 4 open-surgery cases and 8 endovascular-treated cases from November 2008 to December 2012. Patients comprised 8 female and 4 male patients, whose mean age was 46.6 (range 38-56) years. Eleven patients presented with severe headache as the primary symptom, and 1 patient was found with aneurysm incidentally. Preoperative Hunt-Hess graded 0 in 1 patient, graded I in 5 patients, graded II in 4 patients, and graded III in 2 patients. By DSA examinations, 4 blood-blister-like aneurysms located in anterior wall and 8 in medial-anterior wall of supra-clinoid segment of internal carotid artery. Open surgical treatment included direct clipping, trapping, or wrapping and interventional treatment included stent-assisted coiling or simple stent placement. Intra-operative electroencephalogram and somatosensory evoked potentials monitoring was regularly used. Microvascular Doppler ultrasonography and indocyanine green videoangiography were used to assess blood flow in parent and branch vessels. The patients were followed up at 6 months by CT angiography (CTA) examination in outpatient clinic. For 4 open surgeries, 2 aneurysms were directly clipped, 1 was trapped and 1 was wrapped. The patient underwent trapping paralyzed postoperatively. For endovascular treatment, 6 patients were coiled assisted with stents and 2 patients were treated with simple stent placement. All the patients were followed with a mean follow-up time of 16 months (range, 6-61 months). At 6 months follow-up, 3 out of 4 surgical treated patients had good outcome and 1 was moderately severe disabled by modified Rankin scale; 1 patient underwent wrapping recurred and was transferred to endovascular treatment. Of the 6 patients treated with stent-assisted coiling, 4 patients were recurrent and coil replacements were performed. Two patients with simple stent placement had no recurrences. Blood-blister-like aneurysm is a special type of complex cerebral aneurysm. Comprehensive understanding of blood-blister-like aneurysm is the key to successful treatment.Open surgery is difficult procedure with high risk and complications while stent-assisted coiling has a high recurrent rate. To date, neither is the safe and effective treatment option.

Clinical application of intraoperative perfusion CT in carotid endarterectomy

Objective To explore the clinical application of intraoperative perfusion computed tomography (PCT) in carotid endarterectomy (CEA).Methods 11 patients with moderate or severe carotid stenosis (the degree of stenosis greater than 70％ in 8 patients,50％ ～70％ in 3 patients) who underwent CEA in the operating room equipped with intraoperative CT were recruited prospectively from March to July 2012.PCT was performed twice in all cases before and after CEA.The color-coded parameter maps and quantitative data of cerebral blood flow (CBF),cerebral blood volume (CBV) and time to peak (TTP) were calculated,and the relative parameter values of rCBF,rCBV,rTTP based on comparison between operation side and contralateral side were acquired.The PCT parameters before and after CEA were compared.Combined with conventional monitoring methods such as somatosensory evoked potential(SSEP),microvascular doppler ultrasonography (MDU),the role of PCT were assessed.Results All the parameters in anterior communicating artery territory had no significant changes (P ＞ 0.05).In middle cerebral artery territory,only the TTP increased in operation side than in contralateral side while no difference was found in the CBF and CBV before CEA.After CEA,the CBF and CBV increased and TFP decreased in operation side than in contralateral side,and the rCBF and rCBV increased and rTTP decreased obviously comparison with those before CEA (P ＜ 0.05).Of the 11 patients,PCT parameters were improved in all cases.Three patients with the CBF increased more than 70％ after CEA were found.SSEP was normal and MDU abnormal in all cases.The routine CT scan revealed no cerebral hemorrhage.Conclusions Intraoperative PCT could sensitively detect the cerebral hemodynamic changes immediately after CEA through rCBF,rCBV and rTTP.Intraoperative PCT could be an important and adjuvant monitoring method in CEA. Key words: Carotid stenosis; Endarterectomy; Intraoperative perfusion CT

Patterns in neurosurgical adverse events: open cerebrovascular neurosurgery

As part of a project to devise evidence-based safety interventions for specialty surgery, we sought to review current evidence concerning the frequency of adverse events in open cerebrovascular neurosurgery and the state of knowledge regarding methods for their reduction. This review represents part of a series of papers written to consolidate information about these events and preventive measures as part of an ongoing effort to ascertain the utility of devising system-wide policies and safety tools to improve neurosurgical practice. The authors performed a PubMed search using search terms "cerebral aneurysm", "cerebral arteriovenous malformation", "intracerebral hemorrhage", "intracranial hemorrhage", "subarachnoid hemorrhage", and "complications" or "adverse events." Only papers that specifically discussed the relevant complication rates were included. Papers were chosen to be included to maximize the range of rates of occurrence for the reported adverse events. The review revealed hemorrhage-related hyperglycemia (incidence rates ranging from 27% to 71%) and cerebral salt-wasting syndromes (34%-57%) to be the most common perioperative adverse events related to subarachnoid hemorrhage (SAH). Next in terms of frequency was new cerebral infarction associated with SAH, with a rate estimated at 40%. Many techniques are advocated for use during surgery to minimize risk of this development, including intraoperative neurophysiological monitoring, but are not universally used due to surgeon preference and variable availability of appropriate staffing and equipment. The comparative effectiveness of using or omitting monitoring technologies has not been evaluated. The incidence of perioperative seizure related to vascular neurosurgery is unknown, but reported seizure rates from observational studies range from 4% to 42%. There are no standard guidelines for the use of seizure prophylaxis in these patients, and there remains a need for prospective studies to support such guidelines. Intraoperative rupture occurs at a rate of 7% to 35% and depends on aneurysm location and morphology, history of rupture, surgical technique, and surgeon experience. Preventive strategies include temporary vascular clipping. Technical adverse events directly involving application of the aneurysm clip include incomplete aneurysm obliteration and parent vessel occlusion. The rates of these events range from 5% to 18% for incomplete obliteration and 3% to 12% for major vessel occlusion. Intraoperative angiography is widely used to confirm clip placement; adjuncts include indocyanine green video angiography and microvascular Doppler ultrasonography. Use of these technologies varies by institution. A significant proportion of these complications may be avoidable through development and testing of standardized protocols to incorporate monitoring technologies and specific technical practices, teamwork and communication, and concentrated volume and specialization. Collaborative monitoring and evaluation of such protocols are likely necessary for the advancement of open cerebrovascular neurosurgical quality.

Revascularization for Complex Cerebral Aneurysms

Complex cerebral aneurysms may require indirect treatment with revascularization. This manuscript describes various surgical revascularization techniques together with clinical outcomes. Thirty-two consecutive patients with complex cerebral aneurysm were managed from November 2005 to October 2008. Techniques used for revascularization were high-flow bypass, low-flow bypass, branch artery reimplantion, and primary reanastomosis. Physiologic and anatomic monitoring technologies, including electroencephalography, somatosensory evoked potential monitoring, microvascular doppler ultrasonography, and/or indocyanine green videoangiography were used intraoperatively to assess both brain physiology and vascular anatomy. Patient outcome was determined using the Glasgow Outcome Scale at discharge and at a mean of 12 months post operation (range 6-25 months). Two cervical carotid aneurysms (6%) were resected followed by primary reanastomosis, 21 aneurysms (66%) were trapped following saphenous vein high-flow bypasses, five (16%) were clipped after superficial temporal or occipital artery low-flow bypasses, and four (12%) middle cerebral branch arteries were reimplanted. Of the 32 patients at discharge, 29 (91%) had a Glasgow Outcome Scale of four or five, two (6%) had severe disability, and one (3%) died. Cerebral revascularization remains an effective and reliable procedure for treatment of complex cerebral aneurysms. Low morbidity and mortality rates reflect the maturity of patient selection and surgical technique in the management of these lesions.

The analysis of intracranial aneurysms undergoing surgical treatment

To study the surgical principles and treatment options of intracranial aneurysms. One hundred and thirty nine patients with intracranial aneurysms were retrospectively studied, including 80 open-surgery cases and 59 endovascular-treated cases from January to December in 2009. Open surgical methods included clipping, trapping or wrapping and interventional methods included simple coiling or stent-assisted coiling. Intra-operative electroencephalogram and somatosensory evoked potentials monitoring were regularly used. Microvascular doppler ultrasonography and indocyanine green videoangiography were used to assess blood flow in parent and branch vessels. Seventy-three aneurysms were directly clipped, 6 were trapped and 1 was wrapped. Thirty-three aneurysms were coiled and 26 were coiled assisted with stents. At discharge, 71 of the 80(88.8%) surgical treated patients had Glasgow Outcome Scale score of 4 or 5 points, 3 points in 6 patients (7.5%), 2 points in 1 patient (1.2%), and 1 point in 2 patients (2.5%). Fifty-four out of 59 cases underwent endovascular treatment scored 4 or 5 points (91.5%) and 3 points in 5 patients (8.5%). Surgical clipping and endovascular coiling are two major treatment choices for intracranial aneurysms. The treatment option should be individualized based on the patients' specific conditions, which could have a safe, effective and durable outcome.

Microsurgical management of large and giant paraclinoid aneurysms

Background Because of the complex topographic anatomical relationship between vascular, dural and bone structures, paraclinoid aneurysms, especially those of larger size, remain a great challenge for vascular neurosurgeons. We present our microneurosurgical experience of 51 consecutive patients with large and giant paraclinoid aneurysms to scrutinize our personal strategies related to surgical treatment. Methods Fifty-one patients with large or giant paraclinoid underwent micorneurosurgical aneurysm treatment. Operative strategies were planned according to preoperative state-of-the-art imaging studies, and a pterional-transsylvian approach was routinely used. Proximal control of the internal carotid artery (ICA) was achieved by exposure of the cervical portion of the vessel. Intraoperative electroencephalogram and somatosensory evoked potential monitoring, indocyanine green (ICG) videoangiography and/or microvascular Doppler ultrasonography (MDU) were regularly used. A postoperative digital subtraction angiography or computed tomography angiography was performed to verify the efficacy of treatment. Results Forty-three large and giant paraclinoid aneurysm necks (84%) were directly clipped, seven unclippable aneurysms (14%) were trapped with extra-intracranial high-flow revascularization, and one aneurysm (2%) was treated with only ICA proximal Hunterian ligation. Two patients (4%) died in the early postoperative period. In 84% of the patients, the Glasgow Outcome Scale score was 4 or 5 at discharge. At the 6-month follow-up examination, the Rankin Outcome Scale score was 0-2 in 90% of patients. Conclusions Temporary parent vessel occlusion, retrograde suction decompression, endoaneurysmectomy, parent vessel clip reconstruction, and bypass vascular anastomosis are essential techniques to treat complex paraclinoid aneurysms. The combined use of electrophysiological monitoring, MDU, intraoperative ICG videoangiography, and endoscopy can substantially improve microsurgical outcome.

Surgical management of large and giant intracavernous and paraclinoid aneurysms

Due to their location, large and giant intracavernous and paraclinoid aneurysms remain a challenge for vascular neurosurgeons. We identified characteristics, surgical indications and treatment strategies of large and giant intracavernous and paraclinoid aneurysms in 36 patients. The pterional approach was routinely used. The cervical internal carotid artery was exposed for proximal control of parent vessel and retrograde suction decompression. Paraclinoid aneurysms were directly clipped, intracavernous pseudoaneurysm was repaired and the intracavernous aneurysms were trapped with extracranial-intracranial bypass of saphenous vein graft. Intraoperative electroencephalogram (EEG) and somatosensory evoked potential (SSEP) monitoring were used to detect cerebral ischemia during the temporary occlusion of parent arteries. Microvascular Doppler ultrasonography was used to assess blood flow of the parent and branch vessels. Endoscopy was helpful particularly in dealing with internal carotid artery posterior wall aneurysms. Postoperative digital subtraction angiography (DSA) was performed in 33 of the 36 patients. Thirty-two paraclinoid aneurysms were directly clipped, 1 intracavernous pseudoaneurysm was repaired and the other 3 intracavernous aneurysms were trapped with revascularization. Except for two patients who died in the early postoperative stage, 34 patients' follow-up was 6 - 65 months (mean 10 months) and a Glasgow Outcome Scale score of 4 to 5 at discharge. At the 6-month follow-up examination, Rankin Outcome Scale scores were 0 to 2 in 32 patients. EEG and SSEP monitoring changed in six patients. Twelve clips were readjusted when insufficient blood flow in parent and branch vessels was detected. Three posterior wall aneurysms were clipped. Intracavernous aneurysms not amenable to endovascular treatment should be treated surgically and surgical treatment is the first option for paraclinoid aneurysms. The temporary parent vessel occlusion, retrograde suction decompression, endoaneurysmectomy, parent vessel reconstruction, vascular anastomosis, electrophysiological monitoring, Doppler ultrasonography and endoscopy are essential techniques in the treatment of the large and giant intracavernous and paraclinoid aneurysms.

術中モニタリングの有用性と問題点 蛍光脳血管撮影と連続的ドップラー血流検査を用いた脳動脈瘤手術における穿通枝血流不全のモニタリング

We investigated the usefulness of fluorescein cerebral angiography (FAG) and microvascular Doppler ultrasonography (MDU) for detecting the blood flow insufficiency in the perforating arteries during aneurysm surgery. FAG was performed to confirm the patency of perforating arteries located deeply in the surgical field. After aneurysm clipping, the target arteries were illuminated using a beam from the pencil-type probe with a blue light-emitting diode at its tip. After intravenous administration of 5 ml of 10% fluorescein sodium, fluorescence in the vessels was clearly observed through a microscope and recorded on videotape. The excellent image quality and spatial resolution facilitated intraoperative real-time assessment of the patency of the perforating arteries and branches such as the posterior communicating artery, anterior choroidal artery, lenticulostriate artery, recurrent artery of Heubner, hypothalamic artery or posterior thalamoperforating artery. Although MDU has generally been used in aneurysm surgery to assess the blood flow velocity before and after clipping, the complexity of keeping the MDU probe on the target vessel at the appropriate angle and degree of compression makes the detection of changes in flow velocity difficult. To overcome this problem, we continuously measured the blood flow velocity by MDU during aneurysmal clipping. The continuous MDU monitoring during aneurysm clipping enabled us to detect slight blood flow changes in real time. The findings of this study suggest that the monitoring methods introduced here are safe and reliable for detecting intraoperative blood flow insufficiency in the perforating arteries and facilitate the prevention of unexpected postoperative cerebral infarction.

Intraoperative microvascular Doppler ultrasonography monitoring in intracranial aneurysm surgery

To evaluate the reliability of intraoperative microvascular Doppler ultrasonography (MDU) in cerebral aneurysm surgery. MDU was conducted among 46 patients with 51 cerebral aneurysms undergoing 47 operations to examine the blood flow velocity in the aneurysmal sac and in the adjacent vessels before and after aneurysm clipping. MDU verified 6 cases of stenosis or occlusion of an adjacent vessel induced by clip positioning that had escaped detection by visual inspection (12.76%, 6/47). In addition, MDU demonstrated that one out of the 51 aneurysms failed to be occluded (1.96%). The incidence of stenosis, occlusion of adjacent vessel, and aneurysm failing to be occluded was closely correlated with the size of aneurysm, and such conditions were prone to occur in anterior communicating artery (ACoA) and internal carotid artery (ICA) aneurysms. MDU should be used routinely in cerebral aneurysm surgery, especially in cases of giant aneurysms and aneurysms without obvious neck. In cases of ACoA and ICA aneurysms, MDU is more useful.