Category Archives: Vascular

Seven Bypasses: Tenets and Techniques for Revascularization

Seven Bypasses: Tenets and Techniques for Revascularization

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Seven Bypasses: Tenets and Techniques for Revascularization is the third book in a trilogy of bravura, technical nuance, and strategy by master neurosurgeon Michael Lawton. Like his first two books on aneurysms and AVMs, Seven Bypasses provides unparalleled firsthand insights and guidance on complex pathologies in vascular neurosurgery. The fundamentals of microsurgical anastomosis and the craft of bypass surgery are explored in depth with clinical pearls in every chapter.

Lawton eloquently reveals the art of cerebral revascularization in exquisite, metaphorical detail. The surgeon performing bypass surgery is like an architect envisioning and building a beautiful structure. A bypass is designed to fit the patient’s unique anatomy; blueprints designate anastomotic sites, connections, and conduits; the anastomoses are constructed; and the bypass is brought to life with pulsations, flow, and reperfusion. The book highlights Lawton’s aesthetic, which has evolved from the common STA-MCA bypasses to IC-IC bypasses and elaborate arterial reconstructions.

Key Highlights

  • Stepwise discussion of the three anastomoses that form the building blocks of all bypasses: end-to-side, side-to-side, and end-to-end anastomoses
  • Ten tenets delineate nuances of bypass: dexterity, preparing donors and recipients, establishing a working zone, temporary arterial occlusion, arteriotomy, suturing technique, tissue handling, knot tying, patency, and aneurysm occlusion
  • Step-by-step guidance on the seven bypasses: EC-IC bypass, EC-IC interpositional bypass, arterial reimplantation, in-situ bypass, reanastomosis, IC-IC interpositional bypass, and combination bypass
  • Strategies and algorithms for aneurysms organized by specific anatomical sites, including the MCA and the Sylvian cistern, ACA and the interhemispheric cistern, basilar artery and the basal cisterns, and PICA and the cisterna magna
  • More than 1,500 radiographs, operative photographs, and exquisite illustrations drawn by artist Kenneth Xavier Probst elucidate anatomy, surgical principles, and clinical cases

Dr. Lawton has bequeathed a remarkable treasure of knowledge to current and future generations of neurosurgeons and their patients. The Seven series is destined to be an enduring classic for residents, fellows, and neurosurgeons specializing in the treatment of cerebrovascular disease, and for those who believe that manual dexterity and technical skill still matter.

Update: Desmopressin


Desmopressin, sold under the trade name DDAVP among others, is a medication used to treat diabetes insipidus, bedwetting, hemophilia A, von Willebrand disease, and high blood urea levels.

In hemophilia A and von Willebrand disease, it should only be used for mild to moderate cases.

It may be given in the nose, by injection into a vein, by mouth, or under the tongue.

More potent and longer acting than vasopressin.

In patients with central diabetes insipidus DI, desmopressin is the drug of choice.

A synthetic analogue of antidiuretic hormone (ADH), desmopressin is available in subcutaneous, IV, intranasal, and oral preparations.

Generally, it can be administered 2-3 times per day. Patients may require hospitalization to establish fluid needs. Frequent electrolyte monitoring is recommended during the initial phase of treatment.

Alternatives to desmopressin as pharmacologic therapy for DI include synthetic vasopressin and the nonhormonal agents chlorpropamide, carbamazepine, clofibrate (no longer on the US market), thiazides, and nonsteroidal anti-inflammatory drugs (NSAIDs). Because of side effects, carbamazepine is rarely used, being employed only when all other measures prove unsatisfactory. NSAIDs (eg, indomethacin) may be used in nephrogenic DI, but only when no better options exist. In central DI, the primary problem is a hormone deficiency; therefore, physiologic replacement with desmopressin is usually effective. Use a nonhormonal drug for central DI if response is incomplete or desmopressin is too expensive.


Desmopressin (DDAVP) is a well-known hemostatic agent, and recent guidelines already suggest its use in individuals exposed to antiplateletdrugs.

Francoeur et al. hypothesized that DDAVP administration in patients with SAH at admission would be associated with lower risks of intracranial aneurysm rebleeding.

They performed an observational cohort study of patients enrolled in the Columbia University SAH Outcome Project between August 1996 and July 2015. They compared the rate of rebleeding between patients who were and those who were not treated with DDAVP. After adjustment for known predictors, logistic regression was used to measure the association between treatment with DDAVP and risks of rebleeding.

Among 1639 patients with SAH, 12% were treated with DDAVP. The main indication for treatment was suspected exposure to an antiplatelet agent. The overall incidence of rebleeding was 9% (1% among patients treated with DDAVP compared with 8% among those not treated). After adjustment for antiplatelet use and known predictors, treatment with DDAVP was associated with a 45% reduction in the risks of rebleeding (adjusted OR 0.55, 95% CI 0.27-0.97). DDAVP was associated with a higher incidence of hyponatremia but not with thrombotic events or delayed cerebral ischemia.

Treatment with DDAVP was associated with a lower risk of rebleeding among patients with SAH. These findings support further study of DDAVP as first-line therapy for medical hemostasis in patients with SAH 1).

Desmopressin seems to be an effective and accepted as well as frequently adopted measure to antagonize the aspirin effect on platelet function during various major surgical procedures 2).

Bilateral inferior petrosal sinus sampling (IPSS) with desmopressin is a sensitive approach in the diagnosis of Cushing’s disease (CD) and has moderate accuracy in tumour lateralization, making it an alternative choice to IPSS with CRH 3).


Francoeur CL, Roh D, Schmidt JM, Mayer SA, Falo MC, Agarwal S, Connolly ES, Claassen J, Elkind MSV, Park S. Desmopressin administration and rebleeding in subarachnoid hemorrhage: analysis of an observational prospective database. J Neurosurg. 2018 Feb 2:1-7. doi: 10.3171/2017.7.JNS17990. [Epub ahead of print] PubMed PMID: 29393750.


Korinth MC, Gilsbach JM, Weinzierl MR. Low-dose aspirin before spinal surgery: results of a survey among neurosurgeons in Germany. Eur Spine J. 2007 Mar;16(3):365-72. Epub 2006 Sep 5. PubMed PMID: 16953446; PubMed Central PMCID: PMC2200713.


Feng M, Liu Z, Liu X, Zhang X, Bao X, Yao Y, Deng K, Xing B, Lian W, Zhu H, Lu L, Wang R. Tumour lateralization in Cushing’s disease by inferior petrosal sinus sampling with desmopressin. Clin Endocrinol (Oxf). 2018 Feb;88(2):251-257. doi: 10.1111/cen.13505. Epub 2017 Nov 27. PubMed PMID: 29080355.

Ophthalmic artery aneurysm surgery

Ophthalmic artery aneurysm surgery

The ophthalmic artery aneurysms can treated safe and effective through a frontolateral approach 1).

The most important risk associated with clipping ophthalmic artery aneurysms is a new visual deficit. Meticulous microsurgical technique is necessary during anterior clinoidectomy, aneurysm dissection, and clip application to optimize visual outcomes, and aggressive medical management postoperatively might potentially decrease the incidence of delayed visual deficits. As the results of endovascular therapy and specifically flow diverters become known, they warrant comparison with these surgical benchmarks to determine best practices 2).

For ophthalmic artery aneurysm treatment if necessary, the ophthalmic artery may be sacrificed without worsening of vision in the vast majority.

Surgery is technically demanding because these aneurysms are often large and may extend into the cavernous sinus 3) 4) 5) 6) 7) 8).

Care must be taken to avoid optic nerve injury caused by the retraction and/or the heat of the drill 9).

For unruptured intracranial aneurysm, drill off anterior clinoid process via an extradural approach before opening dura to approach aneurysm neck maybe safe. Not for ruptured.

Cutting the falciform ligament early decompresses the optic nerve, and helps minimize worsening of visual impairment from surgical manipulation.

In most cases, a side angled clip can be placed paralell to the parent artery along the neck of the aneurysm 10).

Contralateral approach

Case series


Kamide et al. retrospectively reviewed results from microsurgical clipping of 208 OphA aneurysms in 198 patients.

Patient demographics, aneurysm morphology, clinical characteristics, and patient outcomes were recorded and analyzed.

Despite 20% of these aneurysms being large or giant in size, complete aneurysm occlusion was accomplished in 91% of 208 cases, with OphA patency preserved in 99.5%. The aneurysm recurrence rate was 3.1% and the retreatment rate was 0%.

Good outcomes (modified Rankin Scale score 0-2) were observed in 96.2% of patients overall and in all 156 patients with unruptured aneurysms. New visual field defects (hemianopsia or quadrantanopsia) were observed in 8 patients (3.8%), decreased visual acuity in 5 (2.4%), and monocular blindness in 9 (4.3%). Vision improved in 9 (52.9%) of the 17 patients with preoperative visual deficits.

The most important risk associated with clipping OphA aneurysms is a new visual deficit. Meticulous microsurgical technique is necessary during anterior clinoidectomy, aneurysm dissection, and clip application to optimize visual outcomes, and aggressive medical management postoperatively might potentially decrease the incidence of delayed visual deficits. As the results of endovascular therapy and specifically flow diverters become known, they warrant comparison with these surgical benchmarks to determine best practices 11).


The clinical data of 95 patients with carotid ophthalmic artery aneurysms treated via frontolateral approach in the last 1.5 years in Beijing Tiantan Hospital and Beijing Anzhen Hospital were analyzed retrospectively.Before the operation, digital subtraction angiogram (DSA) was performed among all patients.The patients were divided into two groups by the lateral approach.According to preoperative classification, surgical characteristics and prognosis were summarized.

Ninety-five cases of ophthalmic aneurysms were divided into type Ⅰ of 44 cases (46.3%), type Ⅱ of 34 cases (35.7%) and type Ⅲ of 17cases (17.9%), according to the results of DSA.The diameter of aneurysm was <10 mm (35 cases), 10-25 mm (34 cases), and >25 mm (26 cases). In the 17 cases of subarachnoid hemorrhage (SAH), 8 cases were ruptured carotid-ophthalmic artery aneurysms.Among those 95 patients, 93 were clipped successfully, 2 was trapped.Multiple aneurysms in 5 cases were treated in one surgical session through the same approach.No aneurysm residual was found after postoperative CTA review.Ipsilateral vision of 3 cases were decline.Cerebral infarction was appeared in 9 cases.All the others had a good recovery.

The carotid-ophthalmic artery aneurysms could be well exposed. Microsurgery through frontolateral approach has the advantages such as minimal invasion, less effect on the patients’ look and simple procedure.The frontolateral approach is safe and effective in surgery for ophthalmic segment of the internal carotid artery aneurysms 12).

Case reports

Rustemi et al. illustrated the first case of indocyanine green videoangiography (ICG-VA) application in an optic penetrating ophthalmic artery aneurysm treatment. A 57-year-old woman presented with temporal hemianopsia, slight right visual acuity deficit, and new onset of headache. The cerebral angiography detected a right ophthalmic artery aneurysm medially and superiorly projecting. The A1 tract of the ipsilateral anterior cerebral artery was elevated and curved, being suspicious for an under optic aneurysm growth. Surgery was performed. Initially the aneurysm was not visible. ICG-VA permitted the transoptic aneurysm visualization. After optic canal opening, the aneurysm was clipped and transoptic ICG-VA confirmed the aneurysm occlusion. ICG-VA showed also the slight improvement of the optic nerve pial vascularization. Postoperatively, the visual acuity was 10/10 and the hemianopsia did not worsen.

The elevation and curve of the A1 tract in medially and superiorly projecting ophthalmic aneurysms may be an indirect sign of under optic growth, or optic splitting aneurysms. ICG-VA transoptic aneurysm detection and occlusion confirmation reduces the surgical maneuvers on the optic nerve, contributing to function preservation 13).

1) , 12)

Wang JT, Kan ZS, Wang S. [Surgical management of ophthalmic artery aneurysms via minimally invasive frontolateral approach]. Zhonghua Yi Xue Za Zhi. 2017 Apr 18;97(15):1179-1183. doi: 10.3760/cma.j.issn.0376-2491.2017.15.014. Chinese. PubMed PMID: 28427127.
2) , 11)

Kamide T, Tabani H, Safaee MM, Burkhardt JK, Lawton MT. Microsurgical clipping of ophthalmic artery aneurysms: surgical results and visual outcomes with 208 aneurysms. J Neurosurg. 2018 Jan 26:1-11. doi: 10.3171/2017.7.JNS17673. [Epub ahead of print] PubMed PMID: 29372879.

Hosobuchi Y. Direct surgical treatment of giant intracranial aneurysms. J Neurosurg. 1979;51(6):743–756.

Sundt T M Jr, Piepgras D G. Surgical approach to giant intracranial aneurysms. Operative experience with 80 cases. J Neurosurg. 1979;51(6):731–742.

Almeida G M, Shibata M K, Bianco E. Carotid-ophthalmic aneurysms. Surg Neurol. 1976;5(1):41–45.

Kattner K A, Bailes J, Fukushima T. Direct surgical management of large bulbous and giant aneurysms involving the paraclinoid segment of the internal carotid artery: report of 29 cases. Surg Neurol. 1998;49(5):471–480.

Nutik S L. Ventral paraclinoid carotid aneurysms. J Neurosurg. 1988;69(3):340–344.

Nutik S. Carotid paraclinoid aneurysms with intradural origin and intracavernous location. J Neurosurg. 1978;48(4):526–533

Kumon Y, Sakaki S, Kohno K, Ohta S, Ohue S, Oka Y. Asymptomatic, unruptured carotid-ophthalmic artery aneurysms: angiographical differentiation of each type, operative results, and indications. Surg Neurol. 1997 Nov;48(5):465-72. PubMed PMID: 9352810.

Day AL. Clinicoanatomic features of supraclinoid aneurysms. Clin Neurosurg. 1990;36:256-74. Review. PubMed PMID: 2403885.

Rustemi O, Cester G, Causin F, Scienza R, Della Puppa A. Indocyanine Green Videoangiography Transoptic Visualization and Clipping Confirmation of an Optic Splitting Ophthalmic Artery Aneurysm. World Neurosurg. 2016 Jun;90:705.e5-705.e8. doi: 10.1016/j.wneu.2016.03.010. Epub 2016 Mar 12. PubMed PMID: 26979923.

Update: Unruptured intracranial aneurysm treatment score

Unruptured intracranial aneurysm treatment score

see also PHASES score.

The unruptured intracranial aneurysm treatment score (UIATS) was published in April 2015 as a multidisciplinary consensus regarding treatment of unruptured intracranial aneurysms (UIA).

Etminan et al. endeavored to develop an unruptured intracranial aneurysm treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in Unruptured intracranial aneurysm (UIA) management and research.

An international multidisciplinary (neurosurgery, neuroradiology, neurology, clinical epidemiology) group of 69 specialists was convened to develop and validate the UIATS model using a Delphi consensus. For internal (39 panel members involved in identification of relevant features) and external validation (30 independent external reviewers), 30 selected UIA cases were used to analyze agreement with UIATS management recommendations based on a 5-point Likert scale (5 indicating strong agreement). Interrater agreement (IRA) was assessed with standardized coefficients of dispersion (vr*) (vr* = 0 indicating excellent agreement and vr* = 1 indicating poor agreement).

The UIATS accounts for 29 key factors in UIA management. Agreement with UIATS (mean Likert scores) was 4.2 (95% confidence interval [CI] 4.1-4.3) per reviewer for both reviewer cohorts; agreement per case was 4.3 (95% CI 4.1-4.4) for panel members and 4.5 (95% CI 4.3-4.6) for external reviewers (p = 0.017). Mean Likert scores were 4.2 (95% CI 4.1-4.3) for interventional reviewers (n = 56) and 4.1 (95% CI 3.9-4.4) for noninterventional reviewers (n = 12) (p = 0.290). Overall IRA (vr*) for both cohorts was 0.026 (95% CI 0.019-0.033).

This novel UIA decision guidance study captures an excellent consensus among highly informed individuals on UIA management, irrespective of their underlying specialty. Clinicians can use the UIATS as a comprehensive mechanism for indicating how a large group of specialists might manage an individual patient with a UIA 1)

A tertiary center with focus on vascular neurosurgery, aimed to investigate whether there treatment decision-making in patients with UIA has been in accordance with the published UIATS. A retrospective analysis of patients admitted to the center with UIA was performed. UIATS was applied to all identified UIA. Three decision groups were defined: (a) UIATS favoring treatment, (b) UIATS favoring observation, and © UIATS inconclusive. These results were then compared to our clinical decisions. Spearman’s rank-order correlation (ρ) was run to determine the relationship between the UIATS and our clinical decisions. Cases of discrepancies between UIATS and our clinical decisions were then examined for complications, defined as periprocedural adverse events in treated aneurysms, or aneurysm rupture in untreated aneurysms. Ninety-three patients with 147 UIA were included. A total of 118/147 (80.3%) UIA were treated. In 70/118 (59.3%), UIATS favored treatment, in 18/118 (15.3%), it was inconclusive, and in 30/118 (25.4%), it favored observation. A total of 29/147 (19.7%) UIA were not treated. In 15/29 (51.7%), UIATS favored observation, in 9/29 (31%), it favored treatment, and in 5/29 (17.2%), it was inconclusive (ρ = 0.366, p < 0.01). Discrepancies between UIATS and our clinical decisions did not correlate with complications (ρ = 0.034, p = 0.714). Our analysis shows that our more intuitive clinical decision-making has been in line with UIATS. Our treatment decisions did not correlate with an increased rate of complications 2).

The purpose of the study of Ravindra et al. was to compare the unruptured intracranial aneurysm treatment score (UIATS) recommendations with the real-world experience in a quaternary academic medical center with a high volume of patients with unruptured intracranial aneurysms (UIAs).

All patients with UIAs evaluated during a 3-year period were included. All factors included in the UIATS were abstracted, and patients were scored using the UIATS. Patients were categorized in a contingency table assessing UIATS recommendation versus real-world treatment decision. The authors calculated the percentage of misclassification, sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve. RESULTS A total of 221 consecutive patients with UIAs met the inclusion criteria: 69 (31%) patients underwent treatment and 152 (69%) did not. Fifty-nine (27%) patients had a UIATS between -2 and 2, which does not offer a treatment recommendation, leaving 162 (73%) patients with a UIATS treatment recommendation. The UIATS was significantly associated with treatment (p < 0.001); however, the sensitivity, specificity, and percentage of misclassification were 49%, 80%, and 28%, respectively. Notably, 51% of patients for whom treatment would be recommended by the UIATS did not undergo treatment in the real-world cohort and 20% of patients for whom conservative management would be recommended by UIATS had intervention. The area under the ROC curve was 0.646.

Compared with the authors’ experience, the UIATS recommended overtreatment of UIAs. Although the UIATS could be used as a screening tool, individualized treatment recommendations based on consultation with a cerebrovascular specialist are necessary. Further validation with longitudinal data on rupture rates of UIAs is needed before widespread use 3).


Etminan N, Brown RD Jr, Beseoglu K, Juvela S, Raymond J, Morita A, Torner JC, Derdeyn CP, Raabe A, Mocco J, Korja M, Abdulazim A, Amin-Hanjani S, Al-Shahi Salman R, Barrow DL, Bederson J, Bonafe A, Dumont AS, Fiorella DJ, Gruber A, Hankey GJ, Hasan DM, Hoh BL, Jabbour P, Kasuya H, Kelly ME, Kirkpatrick PJ, Knuckey N, Koivisto T, Krings T, Lawton MT, Marotta TR, Mayer SA, Mee E, Pereira VM, Molyneux A, Morgan MK, Mori K, Murayama Y, Nagahiro S, Nakayama N, Niemelä M, Ogilvy CS, Pierot L, Rabinstein AA, Roos YB, Rinne J, Rosenwasser RH, Ronkainen A, Schaller K, Seifert V, Solomon RA, Spears J, Steiger HJ, Vergouwen MD, Wanke I, Wermer MJ, Wong GK, Wong JH, Zipfel GJ, Connolly ES Jr, Steinmetz H, Lanzino G, Pasqualin A, Rüfenacht D, Vajkoczy P, McDougall C, Hänggi D, LeRoux P, Rinkel GJ, Macdonald RL. The unruptured intracranial aneurysm treatment score: a multidisciplinary consensus. Neurology. 2015 Sep 8;85(10):881-9. doi: 10.1212/WNL.0000000000001891. Epub 2015 Aug 14. PubMed PMID: 26276380; PubMed Central PMCID: PMC4560059.

Hernández-Durán S, Mielke D, Rohde V, Malinova V. The application of the unruptured intracranial aneurysm treatment score: a retrospective, single-center study. Neurosurg Rev. 2018 Feb 1. doi: 10.1007/s10143-018-0944-2. [Epub ahead of print] PubMed PMID: 29388120.

Ravindra VM, de Havenon A, Gooldy TC, Scoville J, Guan J, Couldwell WT, Taussky P, MacDonald JD, Schmidt RH, Park MS. Validation of the unruptured intracranial aneurysm treatment score: comparison with real-world cerebrovascular practice. J Neurosurg. 2017 Oct 6:1-7. doi: 10.3171/2017.4.JNS17548. [Epub ahead of print] PubMed PMID: 28984518.

NeuroEndovascular Challenges: Frontiers in Neurosurgery Volume 1

NeuroEndovascular Challenges: Frontiers in Neurosurgery Volume 1

by Simone Peschillo

List Price: $94.00


Remarkable advances have been made in embolization of cerebral aneurysms, arteriovenous malformations and stroke treatment during the past decades. Endovascular techniques are less invasive than other forms of neurosurgery. However, endovascular neurosurgery is becoming more complicated as the technology is becoming more sophisticated. Frontiers in Neurosurgery is an ebook series which triggers principle issues that still fuel debate in neurosurgery. The series is intended as a reference for practicing endovascular neurosurgeons, vascular neurosurgeons, interventional neurologists and neuroradiologists who have a solid knowledge of neuroangiography. The first volume of this series brings reviews on a variety of challenges that neuroendovascular surgeons can face such as: – Devices for Neuroendovascular Treatment – Dual Antiplatelet Therapy in Neuroendovascular Procedures – Endovascular Reperfusion Management for Acute Ischemic Stroke – Spinal Vascular Pathology – Anesthesia Options for Endovascular Neurosurgery … and much more.