Anatomical Variations Research Articles

Minimally invasive redo tricuspid valve replacement in patient with persistent left superior vena cava.

The management of cardiopulmonary bypass (CPB) is still challenging in certain circumstances, especially for patients with anatomical variations. This challenge is even harder for reoperations, which are associated with increased morbidity and mortality risk. We describe a minimally invasive, beating-heart redo tricuspid valve replacement in a 71-years old woman with persistent left superior vena cava. Preoperative planning via CT-scan, teamwork and custom-made management of CPB are crucial for reoperations with anatomical variations. The perfusionist has a pivotal role in constructing and managing the CPB. We describe a strategy achieving the benefits of minimally invasive endoscopic and beating-heart surgery (avoidance of resternotomy risk and associated morbidity, right ventricular protection) in reoperative tricuspid surgery with persistent upper left vena cava.

The Relationship Between the Retromandibular Vein and the Extratemporal Segment of the Facial Nerve: A Prospective Cadaveric Study of 24 Hemifaces.

Anatomical preservation and functional integrity of the facial nerve (FN) are the main concerns of parotid surgery. Even though a variety of anatomical landmarks have been proposed and widely utilized, temporal or permanent postoperative FN palsy is stilla significant comorbidity of parotid surgery. Therefore, the literature must fully elucidate the consistency of the anatomical relationship between the FN and the retromandibular vein (RMV). We conducted a cadaveric study of 24 hemifaces to map the relationship between the FN and the RMV. Threedistinct patterns were identified.Fourteen of the hemifaces were males, and 10 were females. Thirteen cadaveric dissections were performed on the right side and 11 on the left side. Our study found three distinct patterns and proposed a classification system. Type I (66.7%) is when the nerve lies exclusively lateral to the RMV. Type II (29.2%) is when the FN lies superficial to the RMV, but its mandibular branch lies deep to the anterior branch of the RMV, and type III (4.1%) is when the FN lies exclusively medial to the RMV. The FN and RMV relationship is not constant, and surgeons should be aware of every anatomical variation. Especially in cases where the FN is estimated to lie more in-depth to the level of the RMV, a retrograde approach may be required to avoid a FN injury.

Agenesis of the Celiac Trunk, A Rare Vascular Variant: A Case Report

Vascular anatomical variants of the abdomen are very frequent. Knowledge of these variants is of paramount importance in clinical practice, particularly in surgery, because of the related therapeutic implications. Agenesis of the celiac trunk is one of the rare anatomical variants of the abdominal aorta. A limited number of cases have been reported in the medical literature. We report a case of agenesis of the celiac trunk, with separate emergence of its three branches directly from the abdominal aorta, discovered incidentally during a computed tomography (CT)scan performed as part of extension assessment of gallbladder adenocarcinoma.

Anatomical Markers Associated With the Presence of Intracranial Aneurysms in Individuals Screened for Aneurysms

BACKGROUND Hemodynamic stress is linked to the development of intracranial aneurysms (IAs) and may be influenced by anatomic variation of intracranial arteries. We assessed diameters and bifurcation angles of intracranial arteries forming the circle of Willis in a cohort of individuals screened for the presence of IAs. METHODS Individuals with and without IAs identified at screening with magnetic resonance angiography were compared. Diameters and bifurcation angles of the following arteries were measured using semiautomatic methods: A1 and A2 segments of the anterior cerebral artery, M1 and M2 segments of the middle cerebral artery, P1 segments of the posterior cerebral artery, posterior communicating artery (Pcom), internal carotid artery, vertebral artery, and basilar artery. We employed univariate general linear models to assess group differences. This included subgroup comparisons between individuals with IAs at specific locations and matched controls, and comparisons on group level between individuals with and without IAs, corrected for age and sex. RESULTS In 94 of the 1049 individuals (9.0%) included, IAs were detected. Individuals with middle cerebral artery IAs had wider ipsilateral M2–M2 bifurcation angles compared with controls (121±25° versus 97±19°; P <0.01). Individuals with anterior communicating artery IAs showed smaller angles for the A1–A2 bifurcation (106±16° versus 120±17°; P = 0.02), while those with Pcom IAs had wider Pcom–C7 bifurcation angles (147±14° versus 127±17°; P = 0.02) and smaller diameters below the ipsilateral internal carotid artery top (2.86±0.36 mm versus 3.10±0.33 mm; P = 0.03) compared with controls. CONCLUSION We found associations between wider M2–M2 bifurcation angles or narrower A1–A2 bifurcation angles and IA presence, consistent with prior literature. Moreover, we uncovered previously unexplored associations, including wider Pcom–C7 bifurcation angles and smaller internal carotid artery diameters in individuals with Pcom IAs. Future research should explore the potential of these markers in predicting IAs in at‐risk populations during follow‐up screenings.

Pulmonary Arterial Anatomical Patterns: a Classification Scheme Based on Lobectomy and 3D-CTBA.

Preoperative evaluation of pulmonary vascular and tracheal routes and variations is of great importance to the surgeon. Three-dimensional computed tomography bronchography and angiography (3D-CTBA) has evolved in recent years with the optimization of 3D reconstruction techniques and artificial intelligence. We aim to apply CT angiography and Exoview 3D reconstruction technology to assess patients' pulmonary arterial tree and its anatomical variants and to try to summarize a set of anatomical typing of the pulmonary arterial tree that is relatively easy and conducive to promoting teaching based on surgical habits of lobectomy. A total of 358 patients hospitalized in the Department of Thoracic Surgery of the First Affiliated Hospital of Soochow University between July 2020 and August 2021 were included in this study. We carefully analyzed the site of emanation, alignment, and number of branches of the pulmonary artery according to a uniform classification method in conjunction with the two-dimensional CT images and transformed them into 3D reconstruction models. Different types of pulmonary artery were observed in 358 cases. We evaluated the complete pulmonary artery tree and counted the number and frequency of major arteries of the pulmonary based on the surgical habits of anatomical lobectomy. The 3D-CTBA technique enables us to adequately assess the anatomy of the pulmonary arteries. Moreover, we provide a practical classification scheme of pulmonary arterial anatomical patterns based on lobectomy and 3D-CTBA. Our data can be used by clinicians in the teaching of pulmonary artery anatomy and the preoperative preparation for anatomical lobectomy.

Simulative investigation of the required level of geometrical individualization of the lumbar spines to predict fractures.

Injury mechanisms of the lumbar spine under dynamic loading are dependent on spine curvature and anatomical variation. Impact simulation with finite element (FE) models can assist the reconstruction and prediction of injuries. The objective of this study was to determine which level of individualization of a baseline FE lumbar spine model is necessary to replicate experimental responses and fracture locations in a dynamic experiment.Experimental X-rays from 26 dynamic drop tower tests were used to create three configurations of a lumbar spine model (T12 to L5): baseline, with aligned vertebrae (positioned), and with aligned and morphed vertebrae (morphed). Each model was simulated with the corresponding loading and boundary conditions from dynamic lumbar spine experiments. Force, moment, and kinematic responses were compared to the experimental data. Cosine similarity was computed to assess how well simulation responses match the experimental data. The pressure distribution within the vertebrae was used to compare fracture risk and fracture location between the different models.The positioned models replicated the injured spinal level and the fracture patterns quite well, though the morphed models provided slightly more accuracy. However, for impact reconstruction or injury prediction, the authors recommend pure positioning for whole-body models, as the gain in accuracy was relatively small, while the morphing modifications of the model require considerably higher efforts. These results improve the understanding of the application of human body models to investigate lumbar injury mechanisms with FE models.

A detailed review of the spinal accessory nerve and its anatomical variations with cadaveric illustration.

The spinal accessory nerve, considered part of the eleventh cranial nerve, provides motor innervation to sternocleidomastoid and trapezius. A comprehensive literature review and two cadaveric dissections were undertaken. The spinal accessory nerve originates from the spinal accessory nucleus. Its rootlets unite and ascend between the denticulate ligament and dorsal spinal rootlets. Thereafter, it can anastomose with spinal roots, such as the McKenzie branch, and/or cranial roots. The spinal accessory nerve courses intracranially via foramen magnum and exits via jugular foramen, within which it usually lies anteriorly. Extracranially, it usually crosses anterior to the internal jugular vein and lies lateral to internal jugular vein deep to posterior belly of digastric. The spinal accessory nerve innervates sternocleidomastoid, receives numerous contributions in the posterior triangle and terminates within trapezius. Its posterior triangle course approximates a perpendicular bisection of the mastoid-mandibular angle line. The spinal accessory nerve contains sensory nociceptive fibres. Its cranial nerve classification is debated due to occasional non-fusion with the cranial root. Surgeons should familiarize themselves with the variable course of the spinal accessory nerve to minimize risk of injury. Patients with spinal accessory nerve injuries might require specialist pain management.

An atlas of anatomical variants of the human calcaneus.

The usefulness of anatomical variation is determined by the knowledge of why nonmetric traits appear. Clear descriptions of the traits are a necessary task, due to the risk of confusing anatomical variants and evidence of trauma. Numerous interpretations of the appearance of calcaneal anatomical variants add to the need of an anatomical atlas of calcaneal nonmetric traits. We have analyzed a total of 886 calcanei; 559 belong to different modern and pre-Hispanic samples, and 327 bones were studied from a reference collection from Athens. In this study, we present the anatomical variations that exist on the calcaneus bone, some of which have rarely been mentioned in previous research. The standardization of methods proposed may be useful to experts working in human anatomy, physical anthropology as well as comparative morphology, due to usefulness of this information during surgery, and bioanthropology to observe and study the lifestyle of past populations.

Venous anomalies: an underrecognized but important cause of venous thromboembolism

AbstractAnatomical variants, such as May-Thurner syndrome (MTS) and inferior vena cava (IVC) variants, are underrecognized causes of deep venous thrombosis (DVT), despite affecting management. We aimed to identify the proportion of anatomical variants in proximal lower limb DVT. A retrospective cohort study was performed with cases of acute proximal DVT from 2014 to 2021 identified from ICD-10 codes. We identified 4731 DVTs and included 1268 proximal DVTs. Thirty-six (2.84%) had an anatomical variant (25 MTS and 11 IVC variants), with a rate of 14.39% in females <50 years old. Compared with nonvariant DVTs, they were more likely to be unprovoked (81% vs 23%), younger (median age, 37 vs 63 years), female (67% vs 37%), and have postthrombotic syndrome (22% vs 9%). Variants frequently received thrombolysis (58% vs 1%) or angioplasty (47% vs 0%) and indefinite anticoagulation (83% vs 40%). Further investigation for variants should be considered for high-risk patients, as variants affect management.

Aberrant origin of the left vertebral artery: clinical case and scientific literature

The variants in the origin of the trunks of the aortic arch are very heterogeneous. Among them, it is worth highlighting the variants that involve the origin of the vertebral artery and more specifically the left vertebral artery. We present the case of a 62-year-old patient in whom an aberrant vertebral artery was incidentally described in a computed tomography for oncological evaluation. This anatomical variant is asymptomatic in up to 5% of cases and can give rise to clinical problems of a vascular nature.

Anatomy of the Cavernous Sinus

The cavernous sinus is the crossroad of veins from various embryological origins, including the brain, eye, pituitary gland, dura, and cranium. Embryologically, the cavernous sinus is mainly formed from the pro-otic sinus; secondary anastomosis between the cavernous sinus and primitive tentorial sinus results in various anatomical variations in the drainage patterns of the superficial middle cerebral vein. Moreover, connections between the cavernous sinus and basal vein via the uncal vein, bridging vein, and petrosal vein from the superior petrosal sinus may exist. Retrograde drainage from the cavernous sinus into the cerebral veins is often observed in arteriovenous shunts involving the cavernous sinus, such as dural and carotid-cavernous fistulas, which are primarily treated using transvenous embolization. Understanding the anatomy of the cavernous sinus and its associated veins is essential for safe and reliable endovascular treatment.

Vascular Anatomy of the Middle Cerebral Artery and Cerebral Large Vessel Occlusion

The middle cerebral artery divides into the cortical and perforating branches that supply blood to the extensive cerebral cortex and basal ganglia. In addition to an understanding of the normal vessel diameter and length, endovascular physicians should be familiar with anatomical variations. Understanding the perfusion territory is important for accurate diagnosis of the disease type.

Endodontic management of a maxillary first molar with three roots and six root canals

Variations in the root canal anatomy of a maxillary first molar are often challenging to diagnose and treat; thus, clinicians must have a thorough knowledge of the same. This case report highlights the successful nonsurgical endodontic management of a maxillary first molar with an unusual morphology of three roots and six root canals. A total of six root canals (mesiobuccal [MB] 1, MB2, MB3, distobuccal [DB] 1, DB2, and palatal) were detected after initiating root canal therapy and access cavity preparation. Conventional root canal treatment was completed, and postoperative cone-beam computed tomography scanning was done to verify the total number of canals and ensure the adequacy of root canal fillings. Managing such cases with rare variations in the root canal systems could be arduous and thus, clinicians should be well-versed in the methods to identify and manage such complexities to facilitate the successful outcomes of endodontic treatment.

Acroparesthesias: An Overview.

Acroparesthesia is a symptom characterized by a subjective sensation, such as numbness, tingling, prickling, and reduced sensation, affecting the extremities (fingers and toes). Despite its frequency, data regarding its diagnostic approach and management are scarce. The etiological diagnosis of acroparesthesia is sometimes challenging since it can be due to abnormality anywhere along the sensory pathway from the peripheral nervous system to the cerebral cortex. Acroparesthesia can reveal several diseases. It can be associated with rheumatic complaints such as arthritis or myalgia. Further cautions are required when paresthesia is acute (within days) in onset, rapidly progressive, severe, asymmetric, proximal, multifocal, or associated with predominant motor signs (limb weakness) or severe dysautonomia. Acroparesthesia may reveal Guillain-Barré syndrome or vasculitis, requiring rapid management. Acroparesthesia is a predominant symptom of polyneuropathy, typically distal and symmetric, often due to diabetes. However, it can occur in other diseases such as vitamin B12 deficiency, monoclonal gammopathy of undetermined significance, or Fabry's disease. Mononeuropathy, mainly carpal tunnel syndrome, remains the most common cause of acroparesthesia. Ultrasonography contributes to the diagnosis of nerve entrapment neuropathy by showing nerve enlargement, hypoechogenic nerve, and intraneural vascularity. Besides, it can reveal its cause, such as space-occupying lesions, anatomical nerve variations, or anomalous muscle. Ultrasonography is also helpful for entrapment neuropathy treatment, such as ultrasound-guided steroid injection or carpal tunnel release. The management of acroparesthesia depends on its causes. This article aimed to review and summarize current knowledge on acroparesthesia and its causes. We also propose an algorithm for the management of acroparesthesia.

Colon Volume by Computed Tomography and Scintigraphic Colonic Transit in Constipated Patients With or Without Redundant Colon

Redundant colon, also referred to as "dolichocolon," is an anatomical variant associated with elongation and redundancy thought to be associated with constipation, abdominal pain, and distention.1,2 Diagnosis requires radiological visualization of the non-dilated colon in situ via barium enema or abdominopelvic computed tomography (CT). Colonic redundancy is based on 3 criteria: sigmoid loop displaced cranially relative to the iliac crests (type 1); transverse colon caudal to the iliac crests (type 2); and redundant loops at the hepatic or splenic flexure (type 3).2 Rarely, dolichocolon may meetall 3 criteria.2.

Descripción y prevalencia de la disyunción del anillo mitral y el ventrículo: ¿variante de la normalidad o patológica?

Introduction and objectivesThe aim of this study was to investigate a new variation of the atrial wall-mitral annulus-ventricular wall junction along the mural mitral leaflet and commissures: the ventricular mitral annular disjunction (v-MAD). This new variant is characterized by spatial displacement of the mitral leaflet hinge line by more than 2mm toward the left ventricle. MethodsWe examined a cohort of autopsied human hearts (n=224, 21.9% females, 47.9±17.6 years) from patients without known cardiovascular disease to identify the presence of v-MAD. ResultsMore than half (57.1%) of the hearts showed no signs of MAD in the mural mitral leaflet or mitral commissures. However, v-MAD was found in 23.6% of cases, located within 20.1% of mural leaflets, 2.2% in superolateral commissures, and 1.3% in inferoseptal commissures. V-MAD was not uniformly distributed along the mitral annulus circumference, with the most frequent site being the P2 scallop (19.6% of hearts). The v-MAD height was significantly greater in mural leaflets than in commissures (4.4 mm±1.2 mm vs 2.1 mm±0.1 mm; P<.001). No specific variations in mitral valve morphology or anthropometrical features of donors were associated with the presence or distribution of v-MADs. Microscopic examinations revealed the overlap of the thin layer of atrial myocardium over ventricular myocardium in areas of v-MAD. ConclusionsOur study is the first to present a detailed definition and morphometric description of v-MAD. Further studies should focus on the clinical significance of v-MAD to elucidate whether it represents a benign anatomical variant or a significant clinical anomaly.

Adrenal Vein Sampling: Tips and Tricks.

Adrenal vein sampling (AVS) is the standard method for distinguishing unilateral from bilateral sources of autonomous aldosterone production in patients with primary aldosteronism. This procedure has been performed at limited specialized centers due to its technical complexity. With recent advances in imaging technology and knowledge of adrenal vein anatomy in parallel with the development of adjunctive techniques, AVS has become easier to perform, even at nonspecialized centers. Although rare, anatomic variants of the adrenal veins can cause sampling failure or misinterpretation of the sampling results. The inferior accessory hepatic vein and the inferior emissary vein are useful anatomic landmarks for right adrenal vein cannulation, which is the most difficult and crucial step in AVS. Meticulous assessment of adrenal vein anatomy on multidetector CT images and the use of a catheter suitable for the anatomy are crucial for adrenal vein cannulation. Adjunctive techniques such as intraprocedural cortisol assay, cone-beam CT, and coaxial guidewire-catheter techniques are useful tools to confirm right adrenal vein cannulation or to troubleshoot difficult blood sampling. Interventional radiologists should be involved in interpreting the sampling results because technical factors may affect the results. In rare instances, bilateral adrenal suppression, in which aldosterone-to-cortisol ratios of both adrenal glands are lower than that of the inferior vena cava, can be encountered. Repeat sampling may be necessary in this situation. Collaboration with endocrinology and laboratory medicine services is of great importance to optimize the quality of the samples and for smooth and successful operation. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Successful Thrombolysis in Artery of Percheron Infarction: Grabbed an Extremely Rare Opportunity

Artery of Percheron (AOP) is an uncommon anatomical variation in the posterior circulation neurovasculature. It is a single artery arising from P1 segment of posterior cerebral artery (PCA) which supplies bilateral paramedian thalami and the rostral midbrain and as a result, occlusion of it leads to bilateral thalamic and mesencephalic infarction. Due to very low incidence (ranges from 0.1% to 2% of all ischemic strokes) and varied presentation, the diagnosis of AOP infarction requires strong clinical and radiological suspicion and hence, AOP infarction is often missed and patients are rarely thrombolysed. Here we discuss a patient with acute altered sensorium who recovered completely in short time following treatment with intra-venous thrombolysis for bilateral medial thalamic ischemic stroke due to AOP occlusion.

A Case of Quadrivial Pattern of Right Upper Lobe Bronchus

Abstract The knowledge of the tracheobronchial tree is fundamental for a bronchoscopist, especially for diagnostic, therapeutic, and surgical options that are under consideration. Among all lobes, the right upper lobe (RUL) has a relatively high incidence of tumor and airspace diseases. Most bronchial anomalies are on the right side. Bifurcation is the most common anatomical variation. Quadrification has a very low prevalence. We report the case of a 54-year-old male who came with complaints of hemoptysis and showed a quadrivial type of bronchial division of RUL during a bronchoscopic examination after which three-dimensional computed tomography bronchography showed a supernumerary lateral or axillary segment bronchus. Awareness of this variant may explain otherwise confusing findings and its clinical implication is important for every pulmonologist.

Screening Publicly Available CT Datasets of the Head for Potential Use in Studying Normal and Pathological Issues Related to Nasal Airflow

Objective: The purpose of this study was two-fold. First, we wanted to develop optimized strategies for evaluating publicly available CT datasets for use in simulated studies of airflow. Second, we sought to generate 3D models of the nasal cavity from these CT datasets and perform Computation Fluid Dynamics (CFD) modeling of airflow in the generated models. This work lays the groundwork for future investigations into studying diversity in airflow patterns and rates, analyzing microparticle and odorant deposition, how anatomical variations relate to difference in airflow and pathologies, and the role of comparative CFD analyses in surgical planning. Methods: 490 CT scans were downloaded from the CQ500 repository dataset and evaluated for effectiveness in building digital models of the nasal airway. Scans were digitally dissected and analyzed in 3D Slicer to determine eligibility for model creation and simulation. Eligible scans were further edited in 3D Slicer. All ethmoid air cells, sinuses and recesses were removed, as it was determined these areas do not contribute to the airflow we want to study. These reconstructed models made in 3D Slicer were further refined using the program MeshMixer. Once editing was completed in MeshMixer, STL files were imported back into 3D Slicer to be overlayed with the original STL file created directly from the CT scan to verify anatomical accuracy. Any inaccuracies were removed with further editing in MeshMixer. Models were then imported into Salome, where they were converted into “solid models” for CFD analysis. All CFD was performed in OpenFOAM, and results were visualized using ParaView. Results: Five models have been reconstructed and are being subjected to CFD analysis. To be a strong candidate for modeling, the CT scan had to include at least 230 slices, show all anatomy relevant to the study including turbinates, ethmoid air cells, the cribriform plate and olfactory region, nasal vestibules, and the nasopharynx, and display adequate detail. Of the five final models, four were deemed anatomically normal and all relevant anatomy was intact. One of the five models displayed a deviated septum. The four “normal variants” were used to predict normal patterns of airflow using Computational Fluid Dynamics (CFD). The results of these models compared with the deviated septum model show severe limitation of airflow in the deviated model, together with compensatory flow on the more open side of the airway. Relatively simple digital "corrections" were applied, which effectively recovered normal airflow. Conclusion: CT scans from the publicly available CQ500 repository dataset are effective in creating digital models of the nasal airway to be used for CFD. Computational modeling was shown to be a useful tool in understanding how nasal morphology contributed to the diversity in airflow patterns and rates, microparticle and odorant deposition. Thus far 5 CT scans out of 490 specimens were eligible for modeling; however, due to time constraints of the study, these were the only scans that were utilized. Four of these models were “normal variants” while the scan with a deviated septum was a “pathological variant.” One of the normal models is currently being run in the OpenFOAM CFD program and shows promising results with similar airflow patterns through both the left and right airways. All other models will also be analyzed in this CFD program and more rounds of CFD will be run to compare airflow dynamics for normal and pathological variants. This work provides insights into how a broad, comparative sample of subjects can be used in surgical planning and in understanding the physiological consequences of potential surgical interventions. Burrell College. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.