Anatomical Variations Research Articles

A preliminary study of tracheal morphology in mixed-breed dog cadavers: Anatomical variation of tracheal cartilaginous rings

A preliminary study of tracheal morphology in mixed-breed dog cadavers: Anatomical variation of tracheal cartilaginous rings

Revisiting morphology of xiphoid process of the sternum in human: a comprehensive anatomical study.

The xiphoid process (XP) in animals such as sheep and rats are well known to have cartilage called xiphoidal cartilage (XC). In humans, the cartilage in the xiphoid process is considered an anatomical variant and is not well understood. The aim of this study was to investigate the morphology of the XP. A total of twenty embalmed European descendant cadaveric sterna (aged 52 to 98 years) were used. Transilluminated XPs and midsagittal sections of XPs were used to examine the bone and cartilage. Subsequently, a sagittally-sectioned XP was harvested for histology and stained with Masson's trichrome. The results of the transillumination and histological examinations were compared qualitatively. The dark area visible in transilluminated XPs was consistent with the bony part in the midsagittal XP sections, which contained bone marrow; the bright area was consistent with the cartilage part in the midsagittal XP sections. This was all demonstrated histologically. Most of the XPs (85%) had some portion of cartilage. The XP was classified into four types based on its proportions of bone and cartilage: Type I, no ossification (< 1/3 ossification) 45%; Type II, minor ossification (1/3 - 1/2 ossification) 20%; Type III, major ossification (1/2-2/3 ossification) 20%; Type IV, complete ossification (> 2/3 ossification) 15%. Most of the XPs (85%) had bone and cartilage, which could have been overlooked in studies using skeletons or CT. Previous studies probably underestimated or overestimated the size of the XP. The XC needs to be considered as normal anatomy.

Symptomatic and Morphometric Analysis of Lumbosacral Transitional Vertebrae: Assessments by Age and Gender

Aim: Lumbosakral transitional vertebrae (LSTV) are anatomical variations where a vertebra exhibits characteristics of both lumbar and sacral vertebrae. This study aims to assess anatomical changes in LSTV patients by measuring intervertebral disc height (IVDh), vertebral foramen anteroposterior diameter (FVAPd), and intervertebral foramen height (FIVh), with consideration of age and gender differences. Materials and Methods: This retrospective study included 274 patients diagnosed with LSTV. All MRI images were acquired with a 1.5T MRI machine and a 32-channel lumbar coil. The presence of LSTV, forming the morphological data, was identified from coronal and sagittal reformat images and was classified as either lumbarization or sacralization. Morphometric data (IVDh, FIVh and FVAPd) were acquired from axial, sagittal, and coronal planes using both soft tissue and bone window settings. Results: The mean patient age was 41.6±13.0 years, with a female majority (55.8%). LSTV was predominantly lumbarization (96.4%), with sacralization in the remaining cases. The overall mean FVAPd was 11.2±2.4 mm, mean IVDh was 9.1±1.8 mm, and mean FIVh was 18.8±2.4 mm on the right and 19.1±2.4 mm on the left. IVDh levels were consistent across age groups, while FVAPd values were similar between genders. Patients aged 40 and under had higher FVAPd and FIVh levels, and male patients had higher IVDh and FIVh levels compared to females. Conclusions: The morphometric characteristics of LSTV may vary according to age and gender. Considering these factors in accurately identifying the anatomical variations of LSTV may play a significant role in determining appropriate treatment and management strategies.

Deep Quasi-Recurrent Self-Attention with Dual Encoder-Decoder in Biomedical CT Image Segmentation.

Developing deep learning models for accurate segmentation of biomedical CT images is challenging due to their complex structures, anatomy variations, noise, and unavailability of sufficient labeled data to train the models. There are many models in the literature, but the researchers are yet to be satisfied with their performance in analyzing biomedical Computed Tomography (CT) images. In this article, we pioneer a deep quasi-recurrent self-attention structure that works with a dual encoder-decoder. The proposed novel deep quasi-recurrent self-attention architecture evokes parameter reuse capability that offers consistency in learning and quick convergence of the model. Furthermore, the quasi-recurrent structure leverages the features acquired from the previous time points and elevates the segmentation quality. The model also efficiently addresses long-range dependencies through a selective focus on contextual information and hierarchical representation. Moreover, the dynamic and adaptive operation, incremental and efficient information processing of the deep quasi-recurrent self-attention structure leads to improved generalization across different scales and levels of abstraction. Along with the model, we innovate a new training strategy that fits with the proposed deep quasi-recurrent self-attention architecture. The model performance is evaluated on various publicly available CT scan datasets and compared with state-of-the-art models. The result shows that the proposed model outperforms them in segmentation quality and training speed. The model can assist physicians in improving the accuracy of medical diagnoses.

A retrospective study: Long term prognosis in adults with PA-VSD-MAPCAs

BackgroundPulmonary Atresia, Ventricular Deptal Defect, and Major Aortopulmonary Collateral Arteries (PA-VSD-MAPCAs) is a congenital cyanotic heart defect with poor prognosis. Due to its complex and highly variable anatomy, the best treatment plan is not clear. We aimed (1) to investigate the survival of PA-VSD-MAPCAs patients according to the underlying original anatomy and treatment strategy, and (2) to evaluate life expectancy between patients with or without severe hypoplastic native pulmonary arteries (NPAs) after surgical versus non-surgical treatment. MethodsA prospectively established database of 169 PA-VSD-MAPCAs patients treated and followed up at University Hospitals Leuven was accessed. Patients were divided into three groups according to the treatment strategy. Kaplan-Meier survival curves were plotted, and Log Rank tests were used for comparison. ResultsThe overall mean survival for patients with PA-VSD-MAPCAs was 38.5 years (95%-CI: 33.1–43.9). Patients with complete intracardiac repair had the longest mean survival of 43.8 years (95%-CI: 38.1–49.6) versus the other groups (p < 0.001). A longer mean event-free survival time was found in patients with normal, well-developed NPAs (p = 0.047). Finally, patients with poorly developed or absent NPAs had worse survival rates when a surgical approach was followed. Systemic-pulmonary shunt placement or unifocalisation had limited effect on prognosis in the absence of total repair (p = 0.167). ConclusionsPatients with PA-VSD-MAPCAs who underwent complete intracardiac repair and/or with well-developed native pulmonary arteries had the best prognosis. Our analyzed data suggest that incomplete surgical repair resulted in survival rates comparable to those seen with a non-surgical approach.

Patient-specific mechanical analysis of pedicle screw insertion in simulated osteoporotic spinal bone models derived from medical images.

Biomechanical study. To investigate the mechanical characteristics of bone models created from medical images. Recent advancements in three-dimensional (3D) printing technology have affected its application in surgery. However, a notable gap exists in the analyses of how patient's dimorphism and variations in vertebral body anatomy influence the maximum insertional torque (MIT) and pullout strength (POS) of pedicle screws (PS) in osteoporotic vertebral bone models derived from medical images. Male and female patients with computed tomography data were selected. Dimensions of the first thoracic (T1), fourth lumbar (L4), and fifth lumbar (L5) vertebrae were measured, and bone models consisting of the cancellous and cortical bones made from polyurethane foam were created. PS with diameters of 4.5 mm, 5.5 mm, and 6.5 mm were used. T1 PS were 25 mm long, and L4 and L5 PS were 40 mm long. The bone models were secured with cement, and the MIT was measured using a calibrated torque wrench. After MIT testing, the PS head was attached to the machine's crosshead. POS was then calculated at a crosshead speed of 5 mm/min until failure. The L4 and L5 were notably larger in female bone models, whereas the T1 vertebra was larger in male bone models. Consequently, the MIT and POS for L4 and L5 were higher in female bone models across all PS diameters than in male bone models. Conversely, the MIT for T1 was higher in male bone models across all PS; however, no significant differences were observed in the POS values for T1 between sexes. The mechanical properties of the proposed bone models can vary based on the vertebral structure and size. For accurate 3D surgical and mechanical simulations in the creation of custom-made medical devices, bone models must be constructed from patientspecific medical images.

Computed tomographic characteristics of anatomical variations of external and internal jugular veins in dogs.

The external jugular vein (EJV) has been commonly used for clinical procedures in veterinary medicine, while the internal jugular vein (IJV) has been used mainly for research. Limited literature regarding anatomical variants in both EJV and IJV is available. The objectives of this descriptive retrospective study were to identify the number of dogs with variations of the jugular veins in canine patients undergoing CT of the head and neck and characterize these variations. Of 1000 dogs, 193 dogs (19.3%) had anatomical variations. Six types of anatomical variations were identified. The most common Type I was the absence of the linguofacial vein (72.0%, n=139), with the lingual, facial, and maxillary veins entering the EJV at a common branching point. Type II described a variable course of the EJV and IJV, which in some dogs resulted in the absence of the EJV (14.0%, n=27). Type III was a variable anastomotic loop formed by the linguofacial or maxillary vein cranial or at the junction of the EJV (4.2%, n=8). In Type IV, the EJV was either suspected to be aplastic or markedly reduced in diameter compared with the contralateral side just distal to its formation (3.6%, n=7). Type V was found in only six dogs (3.1%) with unilateral differences in the diameter of the IJV. Six of 193 dogs had a combination of more than one variation (Type VI, 3.1%). Type I was significantly observed more frequently in meso- and dolichocephalic breeds. Type II was significantly observed more frequently in brachycephalic breeds.

Impact of the Aortomitral Positional Anatomy on Atrioventricular Conduction Disorder Following Mitral Valve Surgery.

Variations in the aortomitral positional anatomy, including aortic root rotation appear to be related to variations in the location of the conduction system, including the bundle of His. However, little is known about their clinical significance. This study included 147 patients with normal ECGs who underwent mitral valve surgery. The aortomitral anatomy was classified using preoperative 3-dimensional transesophageal echocardiography, and postoperative conduction disorders, including atrioventricular block and bundle branch block, were analyzed. Variations classified as aortomitral appearance were designated as having a center appearance (85.7%, n=126/147) or lateral appearance (14.3%, n=21/147) on the basis of whether the aortic root was located at the center or was shifted to the left fibrous trigone side. Subsequently, those with a center appearance, aortic root rotation was classified as having a center rotation (83.3% [n=105/126]), in which the commissure of the left and noncoronary aortic leaflet was located at the center, lateral rotation (14.3% [n=18/126]), rotated to the left trigone side, or medial rotation (2.4% [n=3/126]), rotated to the right. The incidence of 3-month persistent new-onset conduction disorder was higher in the lateral appearance than the center appearance group (21.1% versus 5.0%; P=0.031) and higher in the lateral rotation than in the center or medial rotation groups (29.4% versus 1.0% versus 0.0%, respectively; P<0.001). Aortomitral variations can be classified using 3-dimensional transesophageal echocardiography. Lateral appearance and lateral rotation are risk factors for conduction disorders in mitral valve surgery.

Carotid artery stenting in unfavorable vascular anatomy: Effect of embolic protection filter use on periprocedural complications

ObjectiveTo investigate the effect of embolic protection device (EPD) use on periprocedural complications in patients with carotid artery stenosis with anatomical variations. MethodThe study retrospectively evaluated 185 patients who consecutively underwent carotid artery stenting between November 2020 and December 2023. Forty-four patients with difficult anatomical structures, anatomical variations in the common carotid artery (CCA) and internal carotid artery (ICA) (tortuosity, kinking, or coiling), and a CCA-ICA angle of >60 degrees were included in the sample. The patients were divided into two groups according to the use of EPD filters during the procedure and compared in terms of periprocedural events. ResultsOf the 44 patients included in the study, 24 (54.5 %) were male, and the mean age of all patients was 68.7 ± 8.7 years. Comorbidities were present in 93.2 % (n = 41) of the patients. The most common comorbidity was hypertension (n = 32, 72.8 %). The CCA-ICA angle was ≥60 degrees in 45.4 % (n = 20) of all patients. ICA tortuosity was detected in 27.2 % (n = 12) of the patients, ICA kinking in 13.6 % (n = 6), ICA coiling in 6.8 % (n = 3), and CCA tortuosity in 6.8 % (n = 3). Procedure-related periprocedural events developed in 38.6 % (n = 17) of the patients. Postprocedural mortality occurred in two patients, secondary to myocardial infarction in one and COVID-19 pneumonia in the other. There was no significant difference between the filter and non-filter groups in relation to periprocedural events (p = 0.638). Major stroke did not occur in either group. Minor neurological events occurred in 15 % (n = 3/20) of the patients in the filter group and 16.7 % (n = 4/24) of those in the non-filter group. The incidence of vasospasm was statistically higher in patients using filters compared to those without filters (30 % vs. 0 %; P = 0.005, respectively). ConclusionEvaluation of vascular anatomy before carotid artery stenting is important to decide on the technical procedure to be applied in the procedure. The use of EPD in unfavorable anatomy does not reduce periprocedural neurological events. Instead, it results in technical difficulties, prolongs the duration of procedure, and leads to arterial vasospasm. Considering the high periprocedural events in this study, carotid endarterectomy may be a better alternative to endovascular treatment in patients with unfavorable carotid artery anatomy.

Development and validation of a novel vault prediction formula based on structural parameters of the anterior and posterior chambers

BackgroundAccurate prediction of postoperative vault in implantable collamer lens (ICL) implantation is crucial; however, current formulas often fail to account for individual anatomical variations, leading to suboptimal visual outcomes and necessitating improved predictive models. We aimed to verify the prediction accuracy of our new predictive model for vaulting based on anterior and posterior chamber structural parameters.MethodsThis retrospective observational study included 137 patients (240 eyes) who previously underwent ICL surgery. Patients were randomly divided into the model establishment (192 eyes) or validation (48 eyes) groups. Preoperative measurements of the anterior and posterior chamber structures were obtained using Pentacam, CASIA2 anterior segment optical coherence tomography (AS-OCT), ultrasound biomicroscopy, and other devices. Stepwise multiple linear regression analysis was used to evaluate the relationship between the vault and each variable (WL formula). The Friedman test was performed for the vaulting prediction results of the WL, NK (Ver. 3), and KS formulas (Ver. 4) in CASIA2 AS-OCT, as well as the Zhu formula and vault measurements. The proportions of prediction error within ± 250 μm per formula were compared.ResultsThe predicted vault values of the WL, NK, KS, and Zhu formulas and vault measurements were 668.74 ± 162.12, 650.85 ± 248.47, 546.56 ± 128.99, 486.56 ± 210.76, and 716.06 ± 233.84 μm, respectively, with a significant difference (χ2 = 69.883, P = 0.000). Significant differences were also found between the measured vault value and Zhu formula, measured vault value and KS formula, WL formula and Zhu formula, WL formula and KS formula, NK formula and KS formula, and NK formula and Zhu formula (P < 0.001) but not between other groups. The proportions of prediction error within ± 250 μm per formula were as follows: WL formula (81.3%) > NK formula (70.8%) > KS formula (66.7%) > Zhu formula (54.2%).ConclusionsThe WL formula, which considers the complexity of the anterior and posterior chamber structures, demonstrates greater calculation accuracy, compared with the KS (Ver. 4) and Zhu formulas. The proportion of absolute prediction error ≤ 250 μm is higher with the WL formula than with the NK formula (ver. 3). This enhanced predictive capability can improve ICL sizing decisions, thereby increasing the safety and efficacy of ICL implantation surgeries.

Exploratory Study of Biomechanical Properties and Pain Sensitivity at Back-Shu Points.

Hypersensitive acupoints in specific body areas are associated with corresponding internal or visceral disorders. Back-shu points are clinically significant for the diagnosis of visceral organ disease, according to the biomechanical characteristics of the acupoints. In this study, we assessed the biomechanical characteristics and pain sensitivities of five back-shu points linked to five visceral organs in healthy participants. The study included 48 volunteer participants. A myotonometry was used to assess muscle tone and muscle stiffness at five back-shu points associated with visceral organs. Pressure was monitored using a microcontroller and a force sensor. Pain sensitivity was assessed in response to deep pressure pain produced by a constant force. Substantial differences in muscle tone and stiffness were observed at the five back-shu points; muscle tone was highest at BL15, whereas muscle tone and muscle stiffness were lowest at BL23. Moreover, pain sensitivity was significantly different among the acupoints; pain sensitivity was highest at BL23. There was a significant negative correlation between muscle tone and pain sensitivity. We found significant differences in muscle tone, muscle stiffness, and pain sensitivity among five back-shu points associated with visceral organs, which may be attributable to anatomical variations at each point. Our findings suggest that differences at back-shu points should be considered to ensure the accurate diagnosis of visceral disease.

Prevalence and topography of bifid and trifid mandibular canal in Turkish Western Anatolia Population: evaluation of the inferior alveolar canal with CBCT.

Various anatomical variations of the inferior alveolar canal increase the incidence of surgical complications; Therefore, this study aimed to evaluate the frequency and configuration of bifid and trifid mandibular canals using cone beam computed tomography (CBCT) in the Turkish subpopulation. The inferior alveolar canal was evaluated on 1014 hemi-mandibles in the CBCT (I-CAT 3D Imaging System) images of 513 patients. The frequency and configuration of the bifid and trifid mandibular canal (MC) were examined. The relationship between bifid MC configuration and dental status and age groups was analyzed. The distance of the accessory canal to the buccal and lingual walls and the alveolar crest was measured. The diameter of the main canal and accessory canal was measured and its relationship with dental status and age groups was evaluated. Bifid MC was found in 266 hemi-mandibles (24.7%) and 212 (41.3%) of 513 patients. The most common type of bifid MC was the retromolar canal (87 sides), followed by the forward canal without confluence (41; 4%) and the dental canal (34; 3.4%). 10 of the dental canals were opening to the 1st molar, 14 of the 2nd molars, and 10 of the 3rd molars. The number of retromolar foramina was 1 on 56 sides, 2 on 15 sides, and 3 on 4 sides. Forward canal without confluence was more common in edentulous patients than in dentulous patients, while the dental canal was more common in dentulous patients. The main canal diameter was 3.53 ± 0.97mm and the bifid MC diameter was 1.82 ± 0.70mm. Distance of the bifid MC to the lingual wall was higher in the > 64years group than in the 18-39years group (p = 0.022). Distance of the bifid MC to the alveolar crest was lower in the > 64years group compared to the 18-39years group and 40-64years group (p = 0.015). The main canal diameter was higher in the 40-64years group than in the 18-39years group (p = 0.012). Bifid MC has a high prevalence, occurring in almost one in two patients. Dental and retromolar types, which are close to the teeth, are more common, and this increases the possibility of complications. CBCT is the most accurate imaging technique used to detect and define these variations.

Evaluation of the relationship between anatomical variations of the sinonasal cavity and chronic rhinosinusitis through ct scan at a tertiary care center in central India

Evaluation of the relationship between anatomical variations of the sinonasal cavity and chronic rhinosinusitis through ct scan at a tertiary care center in central India

Anomalous origin of Left Main coronary artery from right sinus presenting as non-ST elevation ACS: A case Report

Congenital anomalies of the coronary arteries are a cause of sudden cardiac death. Of the known anatomic variants, anomalous origination of a coronary artery from an opposite sinus of Valsalva (ACAOS) remains a major clinical issue and a challenging condition to treat. Congenital coronary anomalies are likely to be under-recognized, as completing an anatomic assessment in a very large portion of the population would seem unfeasible. However, we present a case report with image of a 54-year-old female presented with acute non-ST elevation ACS for which she underwent diagnostic angiography of the coronary system which revealed a common origin of both right and left main coronary artery from right sinus of Valsa.

ANATOMICAL VARIATIONS IN A FINITE ELEMENT NERVE MODEL OF THE HUMAN FOOT

The nerves in the foot offer a significant role in controlling the movement and correct loading of the foot by providing continuous feedback to the central nervous system. The health importance in the anatomical variations of nerves, such as the locations, the lengths, the communicating branches, and the distance between the adjacent nerve terminals between individuals have given prominence to anatomists as well as physiologists. A previously developed one-dimensional (1D) model of the nerve was extended to determine different anatomical variations in the nerves of the foot, as a realistic anatomical-based variant nerve model of the human foot is not available. The model was verified against experimental data from the literature for communicating branches and distances of various area of the human foot. For instance, the simulated distances of the communicating branches of the plantar nerves and medial dorsal cutaneous nerve (MDCN) division proximal to the first digital space were found to be 43.3 mm and 112.3 mm, respectively, which was in general agreement with the experimental distances of 8-56 mm and 96-116.74 mm, respectively. The developed nerve variant model provides a platform for future studies of the various geometrical and efficient concerns of neurovascular diseases such as diabetic neuropathies by determining the parameters of nerve conduction studies.

Development of a correction coefficient for radiographic evaluation of the alveolar bone crest: a pilot study.

To analyze the differences in cusp height on radiographs, establishing proportional relationships between cusp and alveolar bone crest (ABC) measurements. The goal of this study was to develop a correction coefficient by considering this proportion. Twenty-one artificial teeth, molars and premolars, and bovine ribs were used. Interproximal radiographs were taken with the aid of a positioner. The vertical angles used were: 0°, + 5°, and + 10°, and processed using three spatial resolutions measured in line pairs per mm (lp/mm): 20, 25 and 40. The Perio filter was applied to each image, in addition to the original one. Combinations of angle, resolution, and filter were made. Eighteen images were analyzed by three specialists, resulting in 252 measurements for each evaluator, totaling 756 measurements. The overall variability of the measurements can be explained mainly by the variation in tooth anatomy. The 0° 25 lp/mm Perio filter method was the closest one to the actual clinical scenario for both cusps and ABC. The correction factor managed to explain 71.45% of the errors. The variation in vertical angulation interferes with cusp and ABC measurements, and the angulation at 0º and spatial resolution of 25 lp/mm showed better results. The use of correction coefficients allowed approaching actual measurement values. More accurate ABC height measurements are essential even in radiographic exams that do not meet the standard of excellence because the need to repeat radiographic exams is then eliminated.

The Retromandibular Vein and Its Relation With Facial Nerve Branches: Practical Implications of an Anatomic Variation.

The Retromandibular Vein and Its Relation With Facial Nerve Branches: Practical Implications of an Anatomic Variation.

Anatomical differences of the vertebrobasilar artery between normal subjects and patients with cerebral infarction.

Previous studies have reported various anatomical differences in the cerebral artery between healthy subjects and patients with posterior circulation cerebral infarction. In particular, basilar artery angulation has been associated with posterior circulation cerebral infarction. We compared anatomical variations and the degree of anterior and lateral vertebrobasilar artery angulation and deviation to compare the incidence of cerebral infarction of healthy subjects and patients with posterior circulation cerebral infarction. We compared basilar artery anatomy using brain magnetic resonance angiography in 97 patients who underwent brain magnetic resonance angiography during health checkups at our hospital and in 92 patients diagnosed with posterior circulation cerebral infarction between 2012 and 2022. Anatomical variations, including fetal-type posterior cerebral artery, hypoplastic P1 segment, vertebrobasilar dolichoectasia, and dominant vertebral artery, as well as the degree of anterior and lateral deviation and angulation, were evaluated. Correlations between these variations and the occurrence of cerebral infarction were analyzed. The prevalence of hypoplastic P1 was significantly differences in patients with posterior circulation cerebral infarction (odds ratio: 5.655). Furthermore, patients with posterior circulation cerebral infarction exhibited more acute anterior and lateral angulation, as well as lateral deviation. Hypoplastic P1 and more acute anterior or lateral angulation of the vertebrobasilar artery are associated with increased frequency of cerebral infarction.

Enhancing Forensic Diagnostics: Structured Reporting of Post-Mortem CT versus Autopsy for Laryngohyoid Complex Fractures in Strangulation.

The purpose of this study was to establish a standardized structured workflow to compare findings from high-resolution, optimized reconstructions from post-mortem computed tomography (pmCT) with autopsy results in the detection of fractures of the laryngohyoid complex in strangulation victims. Forty-two strangulation cases were selected, and pmCT scans of the laryngohyoid complex were obtained. Both pmCT scans and autopsy reports were analyzed using a structured template and compared using Cohen's kappa coefficient (κ) and the McNemar test. The study also compared the prevalence of ossa sesamoidea and non-fusion of the major and minor horns of the hyoid bone between both diagnostic methods. The detection of fractures showed a very good correlation between autopsy and pmCT results (κ = 0.905), with the McNemar test showing no statistically significant difference between the two methods. PmCT identified 28 sesamoid bones, 45 non-fusions of the major horns, and 47 non-fusions of the minor horns of the hyoid bone, compared to four, six, and zero, respectively, identified by autopsy (p < 0.0001). Autopsy and pmCT findings correlate well and can be used in a complementary manner. PmCT is superior to autopsy in identifying dislocations and detecting anatomical variations in the laryngohyoid complex, which can lead to misinterpretations during autopsy. Therefore, we do not advocate replacing autopsy with pmCT but propose using a structured workflow, including our standardized reporting template, for evaluating lesions in the laryngohyoid complex.

Right hepatectomy in absence of the left portal vein using the porto-rex shunt procedure

Abstract Objectives Exact knowledge of the portal vein (PV) anatomy is essential for any hepatobiliary procedure. Absence of the portal bifurcation with the complete blood flow to the left lobe coming from the right portal vein (RPV) is an extremely rare anatomical variation. Case presentation In this situation, a solitary metachronous colorectal liver metastasis with suspected infiltration of the RPV and the right bile duct was detected in a 51-year-old male patient. Neither percutaneous ablation nor stereotactic radiotherapy were considered indicated due to the close proximity to the central structures. Hence, a surgical two-step procedure was scheduled. First, a porto-rex shunt with an 8 mm PTFE graft to maintain the portal blood flow to the left lobe was performed. In addition, the RPV was ligated during the same procedure. After recovery, the procedure was completed with a right hepatectomy. The final pathological report confirmed invasion of the right bile duct and the RPV and resection margins were tumor-free. Conclusion This case shows that careful preoperative assessment of vascular anatomy is critical. The use of the porto-rex shunt allowed a potentially curative resection in an otherwise irresectable situation.