Anatomical variations of the sacro-iliac joint: a computed tomography study.

PURPOSE: To identify, describe, and compare the prevalence of sacroiliac joint anatomical variants. METHODS: A retrospective study was performed on computed tomography scans. Joint space was measured, and variants were classified as accessory joint, ileosacral complex, bipartite bony plate, semicircular defect, iliac bony plate, and ossification centers. RESULTS: 400 scans were analyzed. Mean age was 49 years, 180 men (45%), and 220 women (55%). 209 (52.2%) patients presented an anatomical variant with higher prevalence in women (65.4% vs 36.2%), and those older than 40 years of age (60% vs 40%). Mean joint space was similar bilaterally (right 2.41 ± 0.65 mm vs. left 2.37 ± 0.65 mm). Prevalence was: 19.8% accessory joint, 6.5% ileosacral complex, 12.3% bipartite bony plate, 8% semicircular defect, 5% iliac bony plate, and 0.8% for ossification centers. CONCLUSION: Prevalence of anatomical variants of the SIJ is higher in the Hispanic population, women, and those older than 40 years.

Occipital condyle screw fixation viability according to age and gender anatomy: A computed tomography-based analysis.

OBJECTIVE: To assess the Occipital condyle morphology in an all-age population of Northeastern Mexico, and determine age and gender related changes for surgical viability. METHODS: A total of 175 consecutive HRCT scans were included and divided into 5 age groups. The condylar length, width, height, sagittal angle, anterior, posterior and medial intercondylar distances, and intercondylar angle of the OC were measured. RESULTS: Mean condylar length, width, and height in total population were 20.58 mm, 9.42 mm, and 9.02 mm, respectively. Differences were observed in most morphometric parameters when comparing age groups. Significant intergender differences in total population were observed in most parameters, when individualizing each age group the height remained significant in all. The group with the least height measurement was aged 5-9 years, this however, could allow the OC screw (≥6.5 mm) placement. CONCLUSION: Differences in most morphometric parameters of OC were observed between age groups and gender, particularly patients with 5-9 years. However, all groups presented a minimum height that allows the placement of a standard screw. A preoperative imaging study is always recommended due to the variability and complexity of the region.

Gynecological influencing factors on the rectovaginal septum's morphology.

INTRODUCTION AND HYPOTHESIS: The objective was to determine the mean morphometric characteristics of the rectovaginal septum (RVS) and its variations in correlation with the number of pregnancies, method of delivery, parity, and estrogenic exposure. METHODS: An observational, cross-sectional, retrospective, descriptive, and comparative study was carried out. Pelvic MRI of Hispanic women (≥15 years of age) from the northeast of Mexico were obtained. Age and obstetric and gynecological history were registered and the sample women were categorized by their variables. Length and thickness measurements were standardized. RESULTS: A total of 102 MRI studies were included, with a mean age of 41; 24.5% were nulligravida, the rest primi- or multigravida. Vaginal delivery was the most common type (49.35%), 16.88% had a cesarean section, and 31.17% had mixed delivery. 74.5% of the women were premenopausal. The mean RVS length was 73.2 ± 15.3 mm, with a thickness of 2.8 ± 1.7, 2.2 ± 1.2, and 2.5 ± 1.3 mm for the upper, middle, and lower thirds respectively. There were tendencies to increase the length of the RVS, and the thickness of the upper and middle thirds in the non-pregnancy and the at-least-one-pregnancy groups; to increase the length and middle-third thickness in those with mixed delivery, and increased upper- and lower-third thickness in those with only a cesarean section. Multiparous women with vaginal delivery had significantly longer and thicker RVS than primiparous. Premenopausal women had significantly longer RVS with a tendency to lose thickness toward postmenopause. CONCLUSIONS: The morphology of RVS can be modified by different factors such as age, number of pregnancies, number of births, and estrogenic exposure. This structure should be evaluated and taken into account in preoperative management and surgical technique planning.

Origin variations of the superior thyroid, lingual, and facial arteries: a computed tomography angiography study.

PURPOSE: To determine the anatomical variations and morphology of the external carotid artery (ECA) and its anterior branches. METHODS: Using computed tomography angiography (CTA), the origin, internal diameter, and surface laterality emergence of the superior thyroid (STA), lingual (LA), and facial (FA) arteries were evaluated retrospectively evaluated and classified. The bifurcation level of the common carotid artery (CCA) in relation to the cervical vertebrae and disc was also determined. RESULTS: A total of 76 CTA were included in the study. STA originated from the carotid bifurcation (CB) (type I), CCA (type II) and ECA (type III) in 20.4 (31/152), 17.1 (26/152) and 50.7% (77/152) cases, respectively. Also 10.5% (16/152) arose from a shared trunk with LA as a thyrolingual trunk (TLT) (type IVa), and absent in 1.3% (2/152). LA originated in the CB in only one case. A linguofacial trunk (LFT) was present in 14.5% (22/152). Mean diameters of STA, LA and FA were 1.70, 1.95 and 2.45 mm, respectively. Meanwhile, surface laterality were predominately from anteromedial, medial, and anterior, respectively. CB was mainly on C3 or C3-C4 (55.9% of cases). CONCLUSIONS: STA origin below the ECA is a common finding. Our population presented the highest percentage of TLT (10.5%) and high CB (9.8%) in literature. Considering these variations are important to prevent complications in neck surgical procedures.

Avoiding iatrogenic injuries to the vertebral artery: A morphometric study of the vertebral artery-free dissection area.

OBJECTIVE: To determine the area of a safety window that excludes the vertebral artery for the safe access of the occipital condyle screws during occipitocervical fixation. METHODS: This study included 138 cervical computed tomography angiograms. Six measurements per side were made in each imaging study. These measurements are from the vertebral artery to (A) the mastoid process, (B) the mastoid incisura, (C) the posterior condylar fossa, (D) the occipital condyle in its midline, and (E) the medial border of the condyle. We also measured from the tip of the mastoid process to the lower border of the occipital condyle on its lateral side (F). RESULTS: A total of 276 areas from 138 individuals were included, of which 51.4 % were men. The mean age was 54.2 ±â€¯18.63 years. The mean variable measurements (mm) for all the population were 21 ±â€¯4, 16 ±â€¯3, 6 ±â€¯2, 3 ±â€¯2, 2 ±â€¯1 and 35 ±â€¯4 for variables A-F, respectively. We found significant differences between sex when we compared measurements A (p = 0.003), C (p = 0.001), D (p = 0.000) and F (p = 0.000). The incidence rate of dominance for the vertebral artery was 18.8 % and 30.4 % for right and left respectively. CONCLUSION: Women had significantly smaller measures than men. This could indicate a higher risk of iatrogenic injury secondary to a smaller vertebral artery-free area. Results may guide surgeons in the pre-surgical planning aiming to reduce the risk of iatrogenic injuries to the vertebral artery.

Anatomical variations of the acromial and coracoid process: clinical relevance.

PURPOSE: The acromial and coracoid process morphology is of clinical relevance due to associations with functional limitations and shoulder pathology. Our objective was to describe the anatomical characteristics of the acromial and coracoid process using computed tomography (CT). METHODS: Descriptive, observational, transversal and retrospective study. A total of 155 CT of patients without shoulder pathology, of both genders, and indistinct age were evaluated and grouped by age: Group 1 < 25 years; group 2 25-40 years; group 3 > 40 years. The following parameters were evaluated: Acromial type (AcT), vertical coracoid distance (VCD), acromial tilt (AT), acromial projection (AP), critical shoulder angle (CSA), type of the subcoracoid outlet (TSO), and the area of the subcoracoid outlet (ASO). RESULTS: Statistically significant differences were found between men and women for VCD (14.44 ± 4.79 vs. 11.76 ± 4.00 mm; p < 0.001) and AP (3.66 ± 4.71 vs. 1.62 ± 4.99 mm; p < 0.05) as well as between age groups 1 and 3 for AT (35.08 ± 11.53 vs. 28.41 ± 6.60; p < 0.05) and ASO (398.99 ± 153.91 vs. 255.56 ± 124.58 mm2; p < 0.001). An unexpected high ASO variation was identified with 11% of S-shaped acromion and 1.3% clock-shaped TSO. CONCLUSION: The age group between 25-40 years had the most uniform distribution of data. There is a high morphological variability present in an asymptomatic population, which should be considered in the clinical assessment such as shoulder impingement syndrome.

Anatomical variants of anterior cerebral arterial circle: a study by multidetector computerized 3D tomographic angiography / Variantes anatómicas de la región anterior del circulo arterial cerebral: estudio por angiotomografía computarizada 3D

One of the most common causes of stroke is rupture of aneurysms whose approach requires knowledge of anatomical variants. The aim of this study was to determine the prevalence of anatomical variants of the anterior cerebral artery (ACA) and the anterior communicating artery (AComA) by 3D computed tomography angiography (3D CTA) in Mexican individuals. A retrospective, observational, cross-sectional descriptive study of 283 patients, independent of sex or age, in which morphometric measurements of cerebral vessels were evaluated using contrasted 3D CTA from a period of two years was performed. We found at least one "atypical" variant in a third of the study population (33.93 %). The most common "atypical" variant was the absence of the AComA (14.1 %). A significant association between the hypoplastic variant of the right A1 segment and hypoplasia of the left A1 and the right A2 was found, while hypoplasia of the left A1 was associated with hypoplasia of the right A2. There is a difference in the prevalence of anatomical variants of the ACA-AComA complex in Mexican population in relation to other populations. The typical variant is the most prevalent form in the study population. However, the presence of atypical variants represents an important number that should be taken into account in clinical and surgical procedures.

Una de las causas más frecuentes de accidente cerebrovascular es la ruptura de aneurismas cuyo abordaje requiere el conocimiento de las variantes anatómicas. El presente estudio tuvo como objetivo determinar la prevalencia de variantes anatómicas de la Arteria Cerebral Anterior (ACA) y la Arteria Comunicante Anterior (AComA) mediante angiotomografías computarizadas 3D (angioTAC 3D) de individuos mexicanos. Se realizó un estudio retrospectivo, observacional, transversal y descriptivo en el que se evaluaron angioTAC contrastados con reconstrucción 3D de 283 pacientes, sin considerar género ni edad, obtenidas durante un periodo de dos años a los que se les realizaron mediciones morfométricas en los vasos de interés. Se encontró al menos una variante "atípica" en un tercio de la población estudiada (33,93 %). La variante "atípica" más común fue la ausencia de AComA (14,1 %). Se encontró asociación significativa entre la variante hipoplásica del segmento A1 derecha y la hipoplasia de A1 izquierda y A2 derecha; mientras que la hipoplasia de A1 izquierda se asoció a la variante hipoplasia de A2 derecha, encontrándose mayor tendencia de aparición de aneurismas en función del menor diámetro del segmento A2 derecho de la ACA. Existe diferencia en la prevalencia de variantes anatómicas del complejo ACA-AComA en población mexicana con respecto a otras poblaciones. La variante típica constituye la forma más prevalente en la población estudiada. Sin embargo, la presencia de variantes atípicas representa una cifra importante que deberá tomarse en cuenta en procedimientos clínicos y quirúrgicos.

Morphological Analysis of Bronchial Arteries and Variants with Computed Tomography Angiography.

The aim of our study was to determine the prevalence of anatomical variants of bronchial arteries using computed tomographic angiography in a population of northeastern Mexico. An observational, transversal, descriptive, comparative, retrospective study was performed using 139 imaging studies of Mexican patients in which we evaluated the following parameters from the left and right bronchial arteries: artery origin, branching pattern, arterial ostium, vertebral level of origin, diameter, and mediastinal trajectory. The anatomies of the bronchial arteries were similar in both genders, except distribution for vertebral origin level (p 0.006) and the diameter (p 0.013). Left and right arteries were similar, except for the mediastinal trajectory in reference to the esophagus (p < 0.001) as well as the arterial diameter (p < 0.001) and lumen diameter.

Perineural spread-susceptible structures: a non-pathological evaluation of the skull base.

Perineural spread adenoid cystic carcinoma can alter the dimension of foramina and canals of the skull base. The objective of this study was to determine the range of normal variation of the foramina and canals of both hemicranium. We analyzed 200 individuals with no alterations of the skull base in a retrospective manner using high-resolution computed tomography. We measured the short and long axis diameters of the foramen rotundum (FR), foramen ovale (FO), stylomastoid foramen (SMF), pterygoid canal (PTC), internal auditory canal (IAC), and the facial nerve canal in its labyrinthine portion (LPFC) to calculate the area in each hemicranium, compare them and obtain the normal range of asymmetry. Parametric and non-parametric comparison tests were realized. The structures that had the lowest range of asymmetry were the LPFC (0.00-0.79 mm2) and the FR (0.00-2.12 mm2). The one that had the highest asymmetry range was the FO (0.00-9.16 mm2). Significant differences were found in the FO (p = 0.01) and the IAC (p = 0.00) in the gender comparison. We determined a normal asymmetry range of the susceptible foramina and canals of the skull base. This study reports a useful and objective measure to differentiate anatomical from pathological variations of the foramina and canals of the skull base by age and gender. Our results establish a basis for future studies that evaluate this range as a diagnostic tool of metastasis in the skull base as a complement of other imaging techniques.

An age- and gender-related three-dimensional analysis of rotator cuff transverse force couple volume ratio in 304 shoulders.

PURPOSE: The rotator cuff transverse force couple (RCTFC) is fundamental in the shoulder biomechanics, as the balance of its muscle components (the subscapularis relative to the infraspinatus and teres minor) provides stability to the joint. The chronic progression of rotator cuff tears usually present alterations in muscle volume, along with atrophy and compensatory hypertrophy, which can be determined using imaging techniques. The aim of this study was to quantify RCTFC muscle volume in a large sample taking into account the age and gender of the participants involved. METHODS: An observational, retrospective, cross-sectional, descriptive and comparative study was conducted, evaluating thoracic computed tomography scans from 152 patients (304 shoulders) of indistinct gender, with ages ranging between 18 and 85 years. The RCTFC muscle volume was quantified with an oblique/multiplanar segmentation technique. Measuring time was also documented. RESULTS: We observed that muscle volume decreases among the different age (p < 0.04) and gender (p < 0.001) groups. However, the RCTFC volume ratio remained constant at 1.02 ± 0.18 without significant differences throughout all age and gender groups evaluated (p > 0.298). CONCLUSION: The decrease in the RCTFC muscle volume is proportional during the different stages of life, maintaining a constant ratio between its components (physiological RCTFC muscle atrophy). The time-saving segmentation method and volume ratio formula proposed in this study contribute to the management and understanding of rotator cuff tear/pathology.

Pelvimetry by reformatted computed tomography in 290 female pelvis: morphometric variations regarding age / Pelvimetría mediante tomografía computadorizada reformada sobre 290 pelvis femeninas: variaciones morfométricas de acuerdo a la edad

The Mexican government passed a new reform of article 11 of the General Law in 2014 regarding Women's Access to a Life Free of Violence, which states that a cesarean section may not be performed if a vaginal birth is viable. Cesarean sections are excessively indicated in Northen Mexico, using the diagnosis of cephalopelvic disproportion due to a narrow pelvis. Currently, there is no standardized morphometry of the female pelvis in a Mexican population to establish adequate diagnostic parameter. Our study measures the pelvic diameters of the birth canal using abdominopelvic computed tomography (CT). Two hundred and ninety CT from Mexican women between the ages of 18 and 50 were collected and 3D reformatted in order to morphologically measure the pelvic diameters of clinical relevance. Measurements were conducted by two diagnostic imaging specialists. The mean and standard deviation of the measured diameters were: anatomical conjugate diameter (ACD) 11.65±0.99 cm, the obstetric conjugate diameter (OCD) 11.73±0.98 cm, diagonal conjugate diameter (DCD) 12.49±0.98 cm and Interspinous distance (ISD) 10.41±0.78 cm. Significant differences were found in all four mean diameters in between the 20­29 age groups versus the >40, as well as between the 30­39 groups versus the >40. Our study shows that as Mexican women get older, the mean pelvic diameters become narrower.

El Gobierno mexicano aprobó una nueva reforma del artículo 11 de la Ley General del 2014, relativa al acceso de las mujeres a una Vida Libre de Violencia, que establece que una cesárea no se puede realizar si un parto vaginal es viable. Los partos por cesárea son indicados excesivamente en el norte de Mexico, con el diagnóstico de desproporción céfalo-pélvica debido a una estrechez de la pelvis. Actualmente, no existe una morfometría estandarizada de la pelvis femenina en una población mexicana para establecer parámetros de diagnóstico adecuado. Nuestro estudio mide los diámetros pélvicos del canal de parto mediante tomografía compudotarizada (TC) abdomino-pélvica. Se usaron 290 TC de mujeres mexicanas entre 18 y 50 años, los que fueron reformateados en 3D para medir morfológicamente los diámetros pélvicos de relevancia clínica. Las mediciones fueron realizadas por dos especialistas en diagnóstico por imagen. La Media y DE de los diámetros medidos fueron: diámetro anatómico conjugado (DAC) 11,65±0,99 cm, diámetro obstétrico conjugado (DOC) 11,73±0,98 cm, diámetro diagonal conjugado (DDC) 12,49±0,98 cm y distancia interespinosa (DIE) 10,41±0,78 cm. Se encontraron diferencias significativas en las Medias de los cuatro diámetros entre los grupos de 20­29 años de edad frente a las >40 años, así como entre los grupos de 30­39 años frente a los >40 años. Nuestro estudio muestra que a medida que las mujeres mexicanas avanzan en edad, los diámetros pélvicos medios son más estrechos.

Morphometric assessment of the lumbar pedicle isthmus by reformatted CT: variations according to age and gender

This work aims to determine the morphometric characteristics of the lumbar pedicle isthmus with surgical relevance to transpedicular procedures using reformatted computed tomography (CT) and to determine the possible variations in the diameters between genders and age groups. Observational, cross-sectional, descriptive and comparative anatomical studies were carried out. We analyzed 200 CT studies of Mexican patients of known age and gender. The images were analyzed using specialized software for reformatting that could determine cortical and endosteal diameters and cortical thickness at the level of the pedicle isthmus. The mean and standard deviation for each measurement parameter were determined, and a parametric correlation test was performed to compare the variations between the age groups of the same gender. Significant differences in the pedicle diameters between men and women were evident for most of the age groups (p <0.05). The cortical and endosteal pedicle width showed an increase from L1 to L5; the reverse was observed for cortical and endosteal pedicle height. No significant differences were evident with respect to age in the horizontal and vertical diameters for most of the generated study groups. The lateral cortical bone had the lowest scores of the study. The mean values of the morphometric characteristics of the pedicle isthmus obtained in this study will be helpful to conclusively define the pedicle dimensions and to improve the transpedicular approach to the lumbar spine

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