A Morphometric Study of Cadavers for the Anterior Approach to the Lower Lumbar Spine.

AIM: To explore the relationship between the retroperitoneal vasculature and anterior surface of the lower spine, and to establish values for aiding in prediction of the pertinence of anterior approach at the L4-L5 and L5-S1 intervertebral discs. MATERIAL AND METHODS: The study included 13 fresh human cadavers. After exploration of the abdominal cavity and removal of the visceral organs, the vasculature, and anterior spinal surface were revealed beneath the lower extension of the perirenal fascia. Morphometric measurements of the great vessels and the intervertebral discs were obtained. All measurements were analyzed and presented as mean and standard deviation. Differences in the values between sexes were assessed. RESULTS: The anterior height of the L4-L5 and L5-S1 intervertebral disc was 6.8 ± 0.81 mm and 6.7 ± 0.99 mm, respectively. The widths of the aorta, inferior vena cava, right and left common iliac arteries, and right, and left common iliac veins were 16.4 ± 3.58, 20.6 ± 3.36, 11.5 ± 2.32, 11.5 ± 2.43, 14.7 ± 3.13, and 15.5 ± 3.27 mm, respectively. The mean aortic bifurcation angle was 45.5°. The aortic bifurcation was located above the lower endplate of the L4 vertebrae in 53.8% of the cadavers. The area of the interarterial and interiliac trigones was 14.6 ± 5.33 cm < sup > 2 < /sup > and 7.1 ± 4.35 cm2, respectively. No statistically significant differences were noted between the sexes. CONCLUSION: An elaborate radiological examination of the vasculature should be performed prior to surgery to avoid unwanted vascular complications during the anterior approach. Knowing the area of the interarterial and interiliac triangles and the aortic bifurcation location could be aid in assessing the safe working zone.

An updated classification of the anatomical variations of the internal iliac venous drainage system: Surgical implications for anterior lumbar spinal approaches.

BACKGROUND: Advanced pelvic surgery is associated with potential vascular risks. The aim of this study was to complete the existing classification of the anatomical variations of the internal iliac veins encountered on a series of preoperative angio CT with a view to performing anterior lumbar spine surgery. MATERIALS AND METHODS: In this monocentric retrospective study conducted between 2010 and 2020, all preoperative angio CT performed before an anterior lumbar surgery were systematically analyzed. All the abnormalities of the iliac veins were referenced in an updated classification system. RESULTS: 910 patients (431 men and 479 women) with a mean age of 49 years [16-88] were included. Apart from the most common variant in the population (type I), 64 anatomical variations (7.0%) in the iliac veins were reported and classified according to our new classification. The percentage of coverage of the L4-L5 intervertebral disc is 52%, including 32% by the inferior vena cava before the confluence of the common iliac veins. At the level of the L5-S1 intervertebral disc, the coverage is 30% (same distribution between left and right). CONCLUSIONS: Variations of the iliac veins are frequent, and contrary to what one might think, and even if they can represent an anatomical trap during surgery, certain variations do not limit anterior lumbar spine surgery and are not more associated with vascular complications. Nevertheless, these anatomical variations must be known before any advanced pelvic surgery. Depending on their distribution, level L5-S1 is more suitable for ALIF, level L4-L5 for OLIF approaches.

Anatomy of the internal iliac vein around the sacral promontory based on CT three-dimensional (3D) reconstruction.

INTRODUCTION AND HYPOTHESIS: The area around the sacral promontory (SP) is the targeted location of various pelvic operations. We examined the internal iliac vein (IIV) configurations around the SP by computed tomography angiography (CTA) three-dimensional (3D) reconstruction to describe its anatomy and provide accurate anatomical parameters for relevant operations to reduce intraoperative vascular injury. METHODS: We retrospectively studied 2078 CTA 3D model datasets from Nanfang Hospital patients examined for gynecological diseases from December 2009 to October 2020. The IIVs of the above cases were divided into standard and variant IIVs, and variant IIVs were subdivided into different subtypes. To compare the size of the avascular area around the SP between standard and variant IIVs, we selected the two subtypes with the highest variation rate for comparison with the standard IIV type. RESULTS: The most common types of variant IIVs were 5a (5.15%) and 3a (5.05%). The results showed larger values in the standard group than in the 3a and 5a groups for the confluence of common iliac vein (CCIV) height (37.73±12.05 vs. 28.93±10.17 vs. 27.27±7.58 mm, P < 0.05), distance between the iliac vessels (49.47±9.47 mm vs. 37.08±9.36 vs. 37.73±8.94 mm, P < 0.05), and SP exposure width (44.94±6.39 mm vs. 36.83±8.29 vs. 36.93±7.91, P < 0.05). CONCLUSIONS: Variant IIVs may increase the risk of surgery by reducing the avascular area compared with standard IIVs. Therefore, when operating around the SP, special attention should be given to variant IIVs and avoiding vascular injury.

Three-Dimensional in Vivo Anatomical Study of Female Iliac Vein Variations.

OBJECTIVE: To investigate female iliac vein variations by using the computed tomography angiography (CTA) three-dimensional (3 D) reconstruction technique. METHODS: We retrospectively studied 1623 patients undergoing abdominal and pelvic CTA scanning for gynecological diseases from December 2009 to December 2018. Accurate digital 3 D models of the iliac vein were constructed using Mimics 19.0 software and used to study the morphology and variations. Variations in the common iliac vein (CIV), external iliac vein (EIV) and internal iliac vein (IIV) were classified as type I, abnormal number of veins; type II, abnormal communicating branches; or type III, other variations. RESULTS: The overall variation rates of the iliac vein and CIV were 51.57% (837/1623) and 20.33% (330/1623), respectively. The main type of CIV variation was type II. The main type I CIV variation was the absence of the CIV (98.15%), which mostly occurred on the right side (64.81%, 35/54). Type II CIV variation was the most common, with abnormal communicating branches between the left CIV and right IIV (81.78%, 211/258). The overall variation rates of the EIV and IIV were 36.66% (595/1623) and 49.60% (805/1623), respectively, mainly on the right side. The main type of variation was type I. Among them, the division of the IIV into two branches plus convergence with the ipsilateral EIV was the most common (22.98%, 373/1623). CONCLUSION: In this study, approximately half of the patients had iliac vein variations. The preoperative identification of iliac vein variation may reduce vascular injury in pelvic surgery.

Evaluation of iliac venous variations with multidetector computed tomography.

PURPOSE: There are many variations of the iliac vein, and it is aimed to evaluate these variations using multidetector computed tomography (MDCT). METHODS: Pelvic MDCT images of 1071 adult patients (576 males; 495 females; age range 18-94 years; mean age 50.3 years) were retrospectively evaluated. Reconstruction images of the pelvic region in sagittal and coronal planes were evaluated. Except for the usual iliac venous anatomy, all types of iliac vein connections were defined as "iliac venous variation". RESULTS: Of the 1071 patients, 84.2% were considered as type 1 (usual). Different variations were observed in 15.8% of the patients, of whom, 63.9% of were male and 36.1% female, and this gender difference was statistically significant (p < 0.05). The rates of variations detected in the study were type 2 (49.7%), type 3 (29%), type 4 (4.7%), type 5 (6.5%), type 6 (4.8%), type 7 (1.8%) and type 8 (3.6%) respectively. New subtypes that we named as type 3c, type 6f, type 6 × and type 7b were first determined in our study. CONCLUSION: Knowledge and evaluation of iliac venous variations before pelvic surgery or interventional procedures is of importance in preventing possible complications.

Surgical anatomy of the pelvis for total pelvic exenteration with distal sacrectomy: a cadaveric study.

PURPOSE: Intraoperative bleeding from the pelvic venous structures is one of the most serious complications of total pelvic exenteration with distal sacrectomy. The purpose of this study was to investigate the topographic anatomy of these veins and the potential source of the bleeding in cadaver dissections. METHODS: We dissected seven cadavers, focusing on the veins in the surgical resection line for total pelvic exenteration with distal sacrectomy. RESULTS: The presacral venous plexus and the dorsal vein complex are thin-walled, plexiform, and situated on the line of resection. The internal iliac vein receives blood from the pelvic viscera and the perineal and the gluteal regions and then crosses the line of resection as a high-flow venous system. It has abundant communications with the presacral venous plexus and the dorsal vein complex. CONCLUSION: The anatomical features of the presacral venous plexus, the dorsal vein complex, and the internal iliac vein make them highly potential sources of bleeding. Surgical management strategies must consider the anatomy and hemodynamics of these veins carefully to perform this procedure safely.

Identificação pela ultrassonografia vascular da compressão da veia ilíaca comum esquerda em mulheres assintomáticas: ortostatismo pode influenciar o diagnóstico? / Left common iliac vein compression identified by vascular ultrasonography in asymptomatic women: does standing position influence diagnosis?

Resumo Contexto A ultrassonografia vascular é o exame de imagem de escolha para rastreamento inicial da compressão na veia ilíaca comum esquerda, cujo achado assintomático pode ser encontrado em até 25% em algumas casuísticas. Objetivo Identificar, pela ultrassonografia vascular, se há diferença na avaliação da compressão na veia ilíaca comum esquerda em mulheres assintomáticas em decúbito dorsal e ao ortostatismo. Métodos Trata-se de um estudo observacional transversal em 50 mulheres voluntárias, sem sintomas de compressão venosa pélvica. Os parâmetros avaliados pela ultrassonografia vascular em decúbito dorsal e ao ortostatismo foram os diâmetros e as velocidades máximas na veia ilíaca comum esquerda no local do cruzamento com a artéria ilíaca comum direita e antes desse cruzamento, além dos índices de velocidade na veia ilíaca comum esquerda no local do cruzamento. Resultados Foram identificados oito casos de compressão significativa na veia ilíaca comum esquerda na avaliação em decúbito dorsal (16%) e somente dois casos (4%) ao ortostatismo. Os diâmetros na veia ilíaca comum esquerda foram estatisticamente maiores (p = 0,002) no local de cruzamento com a artéria ilíaca comum direita ao ortostatismo, e as velocidades e índices de velocidades foram estatisticamente maiores (p < 0,001) em decúbito dorsal. Não houve identificação de compressão significativa na veia ilíaca comum esquerda em ortostatismo quando os índices de velocidades estavam normais em decúbito dorsal. Conclusão Não houve diferença na detecção de compressão significativa da veia ilíaca comum esquerda ao ortostatismo em relação ao decúbito dorsal; no entanto, o estudo mostrou que pode haver menor compressão anatômica da veia ilíaca comum esquerda em posição ortostática.

Abstract Background Vascular ultrasonography is the imaging exam of choice for initial screening for left common iliac vein compression, which is an asymptomatic finding that can be detected in up to 25% of some patient samples. Objective To determine, using vascular ultrasonography, whether findings of left common iliac vein compression in asymptomatic women are different when assessed in the prone and standing positions. Methods This is a cross-sectional observational study of 50 adult female volunteers with no symptoms of pelvic venous compression. The parameters assessed with vascular ultrasonography in the prone and standing positions were diameters and maximum velocities of the left common iliac vein at the point at which it crosses behind the right common iliac artery and before this point, in addition to left common iliac vein velocity indices at the crossing. Results Eight cases of significant compression of the left common iliac vein were identified when assessed in prone position (16%) and just two cases (4%) were identified in the standing position. Left common iliac vein diameters were statistically larger (p = 0.002) at the point where it crosses behind the right common iliac artery in the standing position and velocities and velocity indices were statistically higher (p < 0.001) in the prone position. No significant compression of the left common iliac vein was identified in the standing position when velocity indices were normal in the prone position. Conclusions There was no difference in detection of significant compression of the left common iliac vein when assessed in the standing position in comparison with assessment in the prone position. However, the study showed that anatomic compression of the left common iliac vein may be reduced in the standing position.

Posterior extrapelvic tributaries to the internal iliac veins: Morphometrics, types, and variants.

BACKGROUND: In the distribution of the veins, it corresponds in the path and by its affluent to their arterial counterpart. For the pelvic surgeon faced with pelvic surgical pathology, the knowledge of the distribution of the venous vessels is especially important in view of novel surgical techniques and current approaches. The majority of the reports are on common iliac vein (CIV) or the inferior vena cava. To the best of our knowledge, there are no papers describing posterior extrapelvic affluents that drain into the internal iliac vein (IIV). OBJECTIVE: The aim of this work was to describe the pattern of the constitution of the IIV in 17 dissection specimens taken at our institution. MATERIALS AND METHODS: We dissected and registered the anatomic variations of the posterior extrapelvic tributaries to the IIVs. RESULTS: Moreover, we describe the presence of a vein here that is, as far as we know, the first report of a vein that is formed from the posterior extrapelvic veins that drain exactly onto the anterior surface of the CIV. We also describe herein the variants that we have found. CONCLUSIONS: The ignorance of the anatomic variations in the posterior extra-pelvic tributaries to the IIVs (internal iliac veins) can lead to fatal consequences in the patients undergoing pelvic surgery.

ANTECEDENTES: En la descripción de los trayectos venosos, estos corresponden casi exactamente a la distribución de su contraparte arterial, como es el caso de la vena iliaca interna. Para el cirujano que se enfrenta a la patología pélvica, el conocimiento de la distribución de los vasos venosos es de particular importancia. Los reportes que describen los grandes vasos venosos pélvicos se enfocan en las venas iliacas comunes o la vena cava inferior. En nuestro conocimiento, no existen ­reportes que describan los afluentes venosos posteriores que drenan a la vena iliaca interna ni las distancias que separan los vasos entre sí. OBJETIVO: Describir el patrón de constitución de la vena iliaca interna en 17 especímenes cadavéricos disecados en nuestra institución. MATERIAL Y MÉTODOS: Se identificaron los trayectos vasculares de los afluentes venosos posteriores extrapélvicos de las venas iliacas primitivas. RESULTADOS: En específico, describimos la presencia de una variante venosa que, hasta donde hemos revisado, es el primer reporte, pues esta vena posterior extrapélvica drena exactamente en la superficie anterior de la vena iliaca común. También describimos otras variantes encontradas. CONCLUSIONES: Conocer las variantes de los afluentes venosos posteriores extrapélvicos es de vital importancia para el cirujano que realiza cirugía pélvica.

Prevalência de compressão da veia ilíaca esquerda em imagens tomográficas de uma população / Prevalence of left iliac vein compression on computed tomography scans from a population

Resumo Contexto A síndrome de May-Thurner (SMT) é a compressão da veia ilíaca esquerda (VIE) entre a artéria ilíaca direita e o corpo vertebral associada à hipertensão venosa crônica unilateral no membro inferior esquerdo. Porém, o achado tomográfico da compressão não necessariamente se reflete em sintomas. Objetivos Avaliar o achado de compressão da veia ilíaca esquerda em tomografias realizadas por outros motivos. Métodos Angiotomografias ou tomografias computadorizadas (TCs) com fase venosa foram analisadas. Foram coletados os dados demográficos e o motivo do exame, quando presente, e foi analisada a relação do diâmetro da veia ilíaca esquerda no ponto de maior compressão com um ponto a montante. Resultados De janeiro a julho de 2016, 590 tomografias foram analisadas, sendo 357 de mulheres e 233 de homens. A compressão da VIE ocorreu em 87 (14,74%) pacientes, dos quais 74 (85,05%) eram mulheres e 13 (14,9%) homens. O diâmetro médio do ponto de maior compressão entre os pacientes que apresentavam VIE < 5 mm foi de 4,4 mm, variando de 2,67 mm a 4,97 mm. O diâmetro no ponto de maior compressão representou até metade do diâmetro na última imagem justaposta ao corpo vertebral (índice de 0,5) em 179 (30,3%) dos pacientes. Conclusões Nosso estudo sugere que a ocorrência de compressão da VIE em TC de pacientes aleatórios, sem conhecimento de insuficiência venosa crônica ou TVP em MIE, é comum. Isso mostra que o achado tomográfico de compressão não necessariamente resulta em sintomas e não deve ser a única razão para tratar um paciente.

Abstract Background May-Thurner syndrome (MTS) is defined as compression of the left iliac vein between the right iliac artery and the lumbar vertebral body in the presence of signs and symptoms of unilateral left chronic venous insufficiency. However, imaging findings of compression are not manifest in symptoms of the syndrome in all subjects. Objectives To evaluate findings of compression in an asymptomatic population. Methods Computed tomography angiographies or venous phase computed tomographies were analyzed. Demographic data and reason for the exam were recorded. Vein diameter was measured at the site of greatest compression and distal of the compression and the ratio between the two diameters was calculated. Results From January to July of 2016, 590 computed tomography scans were analyzed (357 women and 233 men). Left iliac compression was found in 14.74% of patients. Patients with a left iliac diameter below the 5mm threshold had a mean diameter at the site of greatest iliac vein compression of 4.4 mm (range: 2.67 mm-4.97 mm). The ratio between the two measurements was < 0.5 in 30% of patients. Conclusions Our study suggests that iliac vein compression is common among random patients who have had computed tomography for any other reason. This indicates that compression found on tomography images is not the only finding to consider when treating a patient.

Compressões das veias renal e ilíaca comum esquerdas em tomografias computadorizadas: com que frequência são detectadas? / Compression of left renal vein and left common iliac vein on CT scans: how often are they detected?

Resumo Contexto As síndromes de nutcracker e May-Thurner são raras e, apesar de muitas vezes subdiagnosticadas, podem causar sintomas limitantes de gravidade variável. Frequentemente são consideradas diagnóstico de exclusão e não há consenso na literatura quanto a prevalência, incidência e critérios diagnósticos. Objetivos Estimar a frequência da compressão das veias ilíaca comum e renal esquerdas em tomografias computadorizadas de abdome e pelve. Métodos Estudo descritivo, quantitativo e transversal. Para veia renal esquerda, foram considerados como critérios de compressão a relação diâmetro hilar/aortomesentérico > 4 e o ângulo aortomesentérico < 39° e, para veia ilíaca comum esquerda, o diâmetro < 4 mm. Resultados Foram analisadas tomografias computadorizadas de 95 pacientes; destes, 61% eram mulheres e 39% eram homens. A compressão da veia renal esquerda foi encontrada em 24,2% da amostra, com idade média de 48,8 anos, ocorrendo em 27,6% das mulheres e 18,9% dos homens (p = 0,3366). A compressão da veia ilíaca comum esquerda foi detectada em 15,7% da amostra, com idade média de 45,9 anos, ocorrendo em 24,10% das mulheres e 2,7% dos homens (p = 0,0024). Em 7,4% dos pacientes, ambas compressões venosas foram detectadas. Conclusões A compressão da veia renal esquerda ocorreu em mulheres e homens com frequência semelhante, enquanto a compressão da veia ilíaca comum esquerda foi mais frequente em mulheres. Ambas as compressões venosas foram mais frequentemente encontradas em pacientes com idade entre 41 e 50 anos.

Abstract Background The nutcracker and May-Thurner syndromes are rare and, although often underdiagnosed, they can cause limiting symptoms. They are frequently considered only after exclusion of other diagnoses and there is no consensus in the literature on prevalence, incidence, or diagnostic criteria. Objectives To estimate the frequency of compression of the left common iliac vein and left renal vein in CT scans of the abdomen and pelvis. Methods Descriptive, quantitative, cross-sectional study. The criteria used to define compression of the left renal vein were a hilar/aortomesenteric diameter ratio > 4 and aortomesenteric angle < 39° and the criterion for compression of the left common iliac vein was a diameter < 4mm. Results CT scans of 95 patients were analyzed; 61% were women and 39% were men. Left renal vein compression was observed in 24.2% of the sample, with a mean age of 48.8 years, occurring in 27.6% of the women and 18.9% of the men (p = 0.3366). Compression of the left common iliac vein was detected in 15.7% of the sample, with a mean age of 45.9 years, occurring in 24.1% of the women and 2.7% of the men (p = 0.0024). Both veins were compressed in 7.4% of the patients. Conclusions Left renal vein compression was detected in women and men at similar frequencies, whereas left common iliac vein compression was more frequent in women. Both venous compressions were most frequently found in patients aged 41 to 50 years.

The methods for inserting lumbar bicortical pedicle screws from the anatomical perspective of the prevertebral great vessels.

BACKGROUND: At present, bicortical pedicle screws (BPSs) are not used clinically because they carry the potential risk of damaging the prevertebral great vessels (PGVs). The authors observed the anatomical relationship between the PGVs and simulated BPSs at different transverse screw angles (TSAs), exploring the insertion method of the BPS. METHODS: Computed tomography angiography (CTA) images from 65 adults were collected. A total of 4-5 TSAs of the BPSs were simulated on the left and right sides of L1-L5 (L1-L3: 0°, 5°, 10°, 15°; L4-L5: 0°, 5°, 10°, 15°, 20°). There were three types of distances from the anterior vertebral cortex (AVC) to the PGVs (DAVC-PGV); DAVC-PGV < 0.50 cm, DAVC-PGV ≥ 0.50 cm, and DAVC-PGV↑; these distances represented close, distant, and noncontact PGV, respectively. RESULTS: The ratio of every type of PGV was calculated, and the appropriate TSA of the BPS was recommended. In L1, the recommended left TSA of the BPS was 0°, and the ratio of the close PGV was 7.69%, while the recommended right TSA was 0°-10°, and the ratio of the close PGV was 1.54-4.62%. In L2, the recommended left TSA of the BPS was 0° and the ratio of the close PGV was 1.54%, while the recommended right TSA was 0°-15° and the ratio of the close PGV was 3.08-9.23%. In L3, the recommended left TSA was 0°-5°, and the ratio of the close PGV was 1.54-4.62%. In L4, the recommended left TSA was 0°, and the ratio of the close PGV was 4.62%. BPS use was not recommended on the right side of either L3 or L4 or on the either side of L5. CONCLUSIONS: From the anatomical perspective of the PGVs, BPSs were not suitable for insertion into every lumbar vertebra. Furthermore, the recommended methods for inserting BPSs were different in L1-L4.

Anatomical Variations of Iliac Vein Tributaries and Their Clinical Implications During Complex Pelvic Surgeries.

BACKGROUND: During high sacrectomies and lateral pelvic compartment exenterations, isolating the external and internal iliac veins within the presacral area is crucial to avoid inadvertent injury and severe hemorrhage. Anatomical variations of external iliac vein tributaries have not been previously described, whereas multiple classifications of internal iliac vein tributaries exist. OBJECTIVE: We sought to clarify the iliac venous system anatomy using soft-embalmed cadavers. DESIGN: This is a descriptive study. SETTINGS: This study was conducted in Chulalongkorn University, Thailand. PATIENTS: We examined 40 iliac venous systems from 20 human cadavers (10 males, 10 females). INTERVENTIONS: Blue resin dye infused into the inferior vena cava highlighted the iliac venous system, which was meticulously dissected and traced to their draining organs. MAIN OUTCOME MEASURES: Iliac vein tributaries and their valvular system were documented and analyzed. RESULTS: The external iliac vein classically receives 2 tributaries (inferior epigastric and deep circumflex iliac) near the inguinal ligament. However, external iliac vein tributaries in the presacral area were found in 20 venous systems among 15 cadavers (75%). The mean diameter of each tributary was 4.0 ± 0.35 mm, with 72% arising laterally. We propose a simplified classification for internal iliac vein variations: pattern 1 in 12 cadavers (60%) where a single internal iliac vein joins a single external iliac vein to drain into the common iliac vein; pattern 2 in 7 cadavers (35%) where the internal iliac vein is duplicated; and pattern 3 in 1 cadaver (5%) where bilateral internal iliac veins drain into a common trunk before joining the common iliac vein bifurcation. LIMITATIONS: This study is limited by the number of cadavers included. CONCLUSIONS: A comprehensive understanding of previously unreported highly prevalent external iliac vein tributaries in the presacral region is vital during complex pelvic surgery. A simplified classification of internal iliac vein variations is proposed. See Video Abstract at http://links.lww.com/DCR/A900.

Iliolumbar Vein: Anatomy and Surgical Importance During Lateral Transpsoas and Oblique Approaches to Lumbar Spine.

OBJECTIVE: Safe surgical approaches to the anterolateral lumbar spine require a good working knowledge of the anatomy and anatomic variations of this region. As the iliolumbar vein is in the vicinity of both oblique and lateral transpsoas approaches to the lower lumbar spine, the following study was performed to better elucidate its anatomy, variations, and position during such surgical procedures. METHODS: Fifteen (30 sides) fresh frozen adult cadavers underwent dissection of the iliolumbar vein (ILV). The origin, course, variants, relations, and morphometrics of each vein were documented. Fluoroscopy of the vessels was performed. Lastly, anterior oblique and lateral transpsoas approaches to the lumbar spine were carried out in order to evaluate for potential ILV injury. RESULTS: An ILV was found on all but 2 sides (93.3%). It arose as a common trunk from the common iliac vein on 14 sides. Left ILVs tended to have a more distal origin than right ILVs. ILVs had a mean length of 3.7 cm and a mean width of 0.9 cm and were significantly larger on right versus left sides (P < 0.05). Left-sided ILVs tended to have more branches than right-sided veins. The majority of vertical branches of the ILV traveled anterior to the ventral rami of the lumbar spinal nerves, most commonly L4. The ILV and, in particular, its vertical branches coursed next to the L4 and L5 vertebrae. CONCLUSIONS: The ILV should be considered during both oblique and lateral transpsoas approaches to the lumbar spine.

Slc:Hartley guinea pigs frequently possess duplication of the caudal vena cava.

The formation of the caudal vena cava is a complex process involving development, regression, and anastomosis. In mammals, the normal caudal vena cava runs to the right side of the abdominal aorta, while duplication of the caudal vena cava has been identified as a congenital abnormality in both companion animals and humans. The present study demonstrates that Slc:Hartley guinea pigs frequently possess asymptomatic duplicated caudal vena cava. The prevalence was 30% and 24% for males and females, respectively, with no sex-related differences. In accordance with Saad et al. (2012)'s criteria, duplicated caudal vena cava were classified into two distinct variations. The dominant variation was a complete duplication without iliac anastomosis where the left caudal vena cava continued from the left common iliac vein and joined the left renal vein; the left renal vein ran to the right to join the right caudal vena cava. The alternative variation was an incomplete duplication where the left caudal vena cava joined the right infrarenal caudal vena cava at a more cranial point than in normal cases; the renal segment was unchanged. Iliac anastomosis was not found in any cases. Duplicated caudal vena cava neither affected the body weight nor the kidney weight. In conclusion, Slc:Hartley guinea pigs frequently possess asymptomatic duplicated caudal vena cava in the absence of iliac anastomosis and appear to be a novel and useful animal model for duplicated caudal vena cava in animals and humans.

Relationship of blood flow in the common iliac vein to lower urinary tract disease.

PURPOSE: The relationship between blood flow and lower urinary tract disease was explored by measuring blood flow in the common iliac vein to examine the influence of pelvic congestion on lower urinary tract symptoms. METHODS: Color Doppler ultrasonography of the right common iliac vein was performed in 113 men and 60 women, who were outpatients of two Japanese hospitals. Average blood flow velocity and cross-sectional area of the vein were measured, and blood flow volume was calculated. The relationship between these parameters and age or urological diseases was then examined. RESULTS: There was no relation between age and average blood flow velocity or blood flow volume of the common iliac vein in either men or women. However, average common iliac vein blood flow velocity was significantly lower in men with chronic prostatitis and in women with overactive bladder than in other male and female patients, respectively. Common iliac vein blood flow volume was also significantly lower in men with chronic prostatitis than in other male patients. CONCLUSIONS: Men with chronic prostatitis and women with overactive bladder have low blood flow in the common iliac vein, suggesting that pelvic congestion may be related to these two conditions.

The anatomy of the sacral promontory: How to avoid complications of the sacrocolpopexy procedure.

Because of problems with vaginal meshes and the high rate of recurrences of native tissue repair, more and more surgeons treat pelvic organ prolapse with laparoscopic sacrocolpopexy. This surgery requires skilled surgeons. The first step of sacrocolpopexy is the dissection of tissues in front of the sacral promontory to reach the anterior longitudinal ligament. Some complications can occur during this dissection and the attachment of the mesh. This step is dangerous for surgeons because of the proximity of vessels, nerves, and ureters. The lack of knowledge of anatomy can lead to severe complications such as vascular, ureteral, or nerve injuries. These complications can be life-threatening. To show anatomic concerns when surgeons dissect and affix the mesh on the anterior longitudinal ligament, we have developed a video of the promontory anatomy. By reviewing anatomic articles about vessels, nerves, and ureters in this localization, we propose an educational tool to increase the anatomic knowledge to avoid severe complications. In this video, we show an alternative location for dissection and graft fixation when the surgeon believes that mesh cannot be fixed safely on the anterior surface of S1, as currently recommended.

Anatomy of the Internal Iliac Vein: Implications for Uterine Transplant.

STUDY OBJECTIVE: Uterine transplantation has proven feasible since the first live birth reported in 2014. To enable attachment of the uterus in the recipient, long vascular pedicles of the uterine and internal iliac vessels were obtained during donor hysterectomy, which required a prolonged laparotomy to the living donors. To assist further attempts at uterine transplantation, our video serves to review literature reports of internal iliac vein anatomy and demonstrate a laparoscopic dissection of cadaver pelvic vascular anatomy. DESIGN: Observational (Canadian Task Force Classification III). SETTING: Academic anatomic laboratory. Institutional Review Board ruled that approval was not required for this study. INTERVENTION: Literature review and laparoscopic dissection of cadaveric pelvic vasculature, focusing on the internal iliac vein. MEASUREMENTS AND MAIN RESULTS: Although the internal iliac artery tends to have minimal anatomic variation, its counterpart, the internal iliac vein, shows much variation in published studies [1,2]. Relative to the internal iliac artery, the vein can lie medially or laterally. Normal anatomy is defined as some by meeting 2 criteria: bilateral common iliac vein formed by ipsilateral external and internal iliac vein at a low position and bilateral common iliac vein joining to form a right-sided inferior vena cava [2]. Reports show 79.1% of people have normal internal iliac vein anatomy by these criteria [2]. The cadaver dissection revealed internal iliac vein anatomy meeting criteria for normal anatomy. CONCLUSION: Understanding the complexity and variations of internal iliac vein anatomy can assist future trials of uterine transplantation.

A case of double inferior vena cava with renal, ovarian and iliac vein variation.

We encountered a rare case of an anatomic variant of inferior vena cava (IVC) duplication with renal, ovarian and iliac vein variation in an 81-year-old Japanese female cadaver during a student dissection course of anatomy at Aichi Gakuin University School of Dentistry. The two IVCs ran upwards bilaterally to the abdominal aorta. The left IVC joined with the left renal vein (RV) to form a common trunk that crossed anterior to the aorta and ended at the right IVC. We detected a vein [interiliac vein (IiV)] connecting the two IVCs at the level of the aortic bifurcation. The IiV was formed by the union of two tributaries from the left IVC and a tributary from the left internal iliac vein (IIV) and ran obliquely upwards from left to right. Two right ovarian veins, arising separately from the ipsilateral pampiniform plexus, ran vertically in parallel to each other, and each one independently terminated at the right IVC and the right RV. Two right IIVs, connecting each other with small branches, ascended and separately joined the right external iliac vein. The right and left IIVs were connected to each other. These variations cause abnormal drainage, which could lead to clinical symptoms associated with the dysfunction of the vascular and urogenital systems. Here we describe the detailed anatomical features of the area and discuss the related anatomical and developmental aspects.