Variability In Vascular Anatomy Research Articles

The anatomical feasibility of anterior intra- and extra-bifurcation approaches to L5-S1: an anatomic study based on lumbar MRI

BACKGROUND CONTEXTThe anterior approach at L5-S1 has many advantages, however, vascular complications are challenging for spinal surgeons who may not be familiar with the variability of vascular anatomy. There are three different anterior approaches (intra-bifurcation approach and extra-bifurcation: left-, and right-sided prepsoas approaches) described in previous studies to respond to the variability of anterior vascular anatomy for reduction in vascular injury, while no guidance for the choice of approach preoperatively. PURPOSETo analyze the anatomical feasibility of three anterior approaches to access the L5-S1 disc space according to a practical framework. STUDY DESIGNRetrospective study. PATIENT SAMPLELumbar magnetic resonance imaging (MRI) from patients who visited our outpatient clinic were reviewed, with 150 cases meeting the inclusion criteria. OUTCOME MEASURESThe following radiographic parameters were measured on axial T2-weighted MRI at the lower endplate of L5 and the upper endplate of S1: width of the vascular corridor, position of the left and right common iliac vein (CIV), and presence of perivascular adipose tissue (PAT). Moreover, we designed a safe line to evaluate the feasibility of left- and right-sided prepsoas approaches. Cases of lumbosacral transitional vertebrae were identified. METHODSThe feasibility of the intra-bifurcation approach was determined by the width of the vascular corridor, presence of PAT, and the position of the CIV. The feasibility of the prepsoas approach was determined by the relative position of the CIV to the safe line, presence of PAT, and the intersection point of the CIV and vertebral body. RESULTSSixty-eight percent, 64.7%, and 75.3% cases allowed the intra-bifurcation, left-, and right-sided prepsoas approach to L5-S1, respectively. The cases in this study had at least one of three anterior approaches to access L5-S1 disc space, and 74% of cases had more than one anatomical feasibility of anterior approach. The right-sided prepsoas approach was feasible in the majority of cases because of the vertical course of the right CIV with a significantly higher proportion of presence of PAT. Patients with lumbosacral transitional vertebrae (24 cases) may prefer the prepsoas approaches, and only six cases (25.0%) were determined to be feasible for the intra-bifurcation approach. CONCLUSIONSOur study proposes a practical framework to determine whether the three different anterior approaches are feasible access at L5-S1. According to the framework, all cases had the anatomical feasibility of using an anterior approach to access L5-S1, and three-fourths of cases had a replaceable anterior approach when encountering intraoperative difficulties.

Transradial Versus Transfemoral Approach for Endovascular Thrombectomy of Left Anterior Circulation Stroke With Bovine Arch

Transradial Versus Transfemoral Approach for Endovascular Thrombectomy of Left Anterior Circulation Stroke With Bovine Arch

EP.FRI.265 Laparoscopic Right Hemicolectomy with Complete Mesocolic Excision for a T4 Caecal Tumour with Associated Phlegmon

Abstract A 67-years-old female presented with right lower abdominal pain and raised inflammatory markers. A computed tomography scan showed marked inflammatory changes with collections adjacent to terminal ileum. Patient was managed with intravenous antibiotics initially. Subsequent colonoscopy showed a bulky 8cm caecal pole tumour involving ileocaecal valve. Histopathology confirmed a diagnosis of moderately differentiated adenocarcinoma. Staging CT was negative for distant metastases. The patient subsequently proceeded to laparoscopic right hemicolectomy with complete mesocolic excision (CME). Intraoperatively the ileocolic vein was clipped just at the level of its confluence with superior mesenteric vein. The ileocolic artery was divided at its origin form superior mesenteric artery followed by division of right colic artery. The caecal mass was dissected off the abdominal wall. Proximally small bowel was resected 25cm form the ileocaecal valve and distally colon was divided up till mid transverse point. The specimen was extracted through a 9 cm Pfannenstiel incision. An intracorporeal isoperistaltic ileocolic side to side anastomosis was performed using a novel technique.1 The patient made full recovery and proceeded to adjuvant chemotherapy. Histology showed moderately differentiated T4 adenocarcinoma with tumour free lymph nodes. This case demonstrates intraoperative steps of laparoscopic complete mesocolic excision. CME is now becoming a standard due to improved oncological outcomes as it yields higher number of resected lymph nodes and better tumour clearance margins. This approach can be challenging due to variability in vascular anatomy, however, in experienced hands it is feasible and safe resulting in extensive lymphadenectomy and better oncological radicality. 1.https://www.ncbi.nlm.nih.gov/pubmed/28833963/

A Novel Augmented Reality-Based Navigation System in Perforator Flap Transplantation - A Feasibility Study.

In perforator flap transplantation, dissection of the perforator is an important but difficult procedure because of the high variability in vascular anatomy. Preoperative imaging techniques could provide substantial information about vascular anatomy; however, it cannot provide direct guidance for surgeons during the operation. In this study, a navigation system (NS) was established to overlie a vascular map on surgical sites to further provide a direct guide for perforator flap transplantation. The NS was established based on computed tomographic angiography and augmented reality techniques. A virtual vascular map was reconstructed according to computed tomographic angiography data and projected onto real patient images using ARToolKit software. Additionally, a screw-fixation marker holder was created to facilitate registration. With the use of a tracking and display system, we conducted the NS on an animal model and measured the system error on a rapid prototyping model. The NS assistance allowed for correct identification, as well as a safe and precise dissection of the perforator. The mean value of the system error was determined to be 3.474 ± 1.546 mm. Augmented reality-based NS can provide precise navigation information by directly displaying a 3-dimensional individual anatomical virtual model onto the operative field in real time. It will allow rapid identification and safe dissection of a perforator in free flap transplantation surgery.

Surgical anatomy of the common iliac veins during para-aortic and pelvic lymphadenectomy for gynecologic cancer

ObjectiveCompression of the left common iliac vein between the right common iliac artery and the vertebrae is known to be associated with the occurrence of left iliofemoral deep vein thrombosis (DVT). In this study, we described the variability in vascular anatomy of the common iliac veins and evaluated the relationship between the degree of iliac vein compression and the presence of DVT using the data from surgeries for gynecologic cancer.MethodsThe anatomical variations and the degrees of iliac vein compression were determined in 119 patients who underwent systematic para-aortic and pelvic lymphadenectomy during surgery for primary gynecologic cancer. Their medical records were reviewed with respect to patient-, disease-, and surgery-related data.ResultsThe degrees of common iliac vein compression were classified into three grades: grade A (n=28, 23.5%), with a calculated percentage of 0%-25% compression; grade B (n=47, 39.5%), with a calculated percentage of 26%-50% compression; and grade C (n=44, 37%), with a calculated percentage of more than 50% compression. Seven patients (5.9%) had common iliac veins with anomalous anatomies; three were divided into small caliber vessels, two with a flattened structure, and two had double inferior vena cavae. The presence of DVT was associated with the elevated D-dimer levels but not with the degree of iliac vein compression in this series.ConclusionAlthough severe compression of the common iliac veins was frequently observed, the degree of compression might not be associated with DVT in surgical patients with gynecologic cancer. Anomalous anatomies of common iliac veins should be considered during systematic para-aortic and pelvic lymphadenectomy in the gynecologic cancer patients.

Abstract WP258: ZBTB7C Is Associated With Severity Of Infarction In Cerebral Ischemia

Background Stroke is a complex disease that is affected by multiple genetic and environmental factors. We utilize the variability in inbred mouse strains to evaluate the genetic basis of susceptibility to cerebral infarction. Methods To identify candidate genes that contribute to this variability in susceptibility, we performed a strain survey on 33 inbred strains of mice using a permanent middle cerebral artery occlusion model. Variability in vascular anatomy was determined by examining the circle of Willis in 22 strains of mice. Infarct volume was obtained and a genome-wide association mapping was performed on 118,019 SNPs using efficient mixed-model association (EMMA) to account for population structure and genetic relatedness in inbred mice. Candidate genes from mice were validated in 34 patients with M1 occlusions from the Genes Associated with Stroke Risk and Outcomes Study (GASROS) and the STOP Stroke Study Results Two SNPs reached genome-wide significance (rs32249495 p=2.08x10-7 and rs3694965 p=2.17x10-7) and two were suggestive (rs31924033 5.61x10-6 and rs3677406 9.46x10-6). Thirty-eight genes were identified to be within 500kb of these four SNPs, corresponding to twenty-four orthologous human genes. SNPs associated with the human orthologs were validated in patients with M1 occlusions. Of these, one SNP (rs1944586, p=1.06x10-4) corresponding to the ZBTB7C gene was significant after adjusting for multiple testing. In vitro analysis demonstrated upregulation of ZBTB7C expression in endothelial cells under hypoxic conditions. Conclusion ZBTB7C may be part of a novel genetic pathway that modulates the severity of cerebral infarction and may serve as a new target for therapeutic intervention in cerebral ischemia.

Superior and inferior gluteal artery perforators: In-vivo anatomical study and planning for breast reconstruction

Gluteal artery perforator (GAP) flaps have gained popularity in autologous breast reconstruction, however substantial variability in vascular anatomy has limited their more widespread utilisation. While previous anatomical studies have been limited by specimen numbers and study design, computed tomographic angiography (CTA) can demonstrate in-vivo vascular anatomy in large numbers. We thus undertook an anatomical study with the use of CTA, the largest such study in the literature, and present a clinical series utilising CTA to plan GAP flaps. Eighty consecutive patients (160 gluteal regions) underwent pre-operative CTA, with superior and inferior gluteal artery perforators (SGAPs and IGAPs) assessed for location, size and course. The utility of pre-operative CTA is explored in a series of seven consecutive patients undergoing autologous breast reconstruction. There were an average of 11 SGAPs per region (range 6-17), with mean diameter 0.6mm (range 0.3-2.4) and SGAPs >0.8mm diameter identified in every region. In contrast, there were nine IGAPs per region (range 5-14), with mean diameter 0.4mm (range 0.3-1.6) and IGAPs >0.8mm diameter identified in 95% of regions. Individual SGAP and IGAP territories were different between sides and between individuals, with the central tissue variably supplied by either system. In a clinical series, CTA was found to aid operative planning and correlate with operative findings. There are regularly abundant SGAPs and IGAPs identifiable per gluteal region, and while many are diminutive in size, the identification of suitable perforators with CTA may aid operative planning for gluteal flap harvest.

Cardiac arrest cerebral ischemia model in mice failed to cause delayed neuronal death in the hippocampus

Global cerebral ischemia models for genetically engineered mice are of particular importance for the study of delayed neuronal death, but have been complicated by variability of vascular anatomy. Here we developed a 5-min cardiac arrest model that was not affected by vascular anatomy, and evaluated the hippocampal neuronal injury in BL/6 and SV129 mice. Despite prolonged anoxic depolarization for approximately 7 min, however, no consistent ischemic neuronal injury was noted in the CA1 sector of the hippocampus in both strains. Thus, our observations suggested that murine hippocampal neurons are relatively resistant to ischemia compared with those in other rodents.

Hepatic pseudotumour — Caudate lobe sparing in fatty liver

Due to the large variability in vascular anatomy of the caudate lobe, this part of the liver may give rise to puzzling phenomena in imaging technics. We present a case of generalized fatty liver in which the enlarged caudate lobe was displayed as a hypoechoic area masquerading in ultrasonography as a hepatic tumour.