As dimensões ósseas da pelve podem estar relacionadas à gênese dos prolapsos de órgãos pélvicos? Uma revisão sistemática de estudos observacionais para avaliação de risco e prognóstico / Can the bone dimensions of the pelvis be related to the genesis of pelvic organ prolapses? A systematic review of observational studies for risk assessment and prognosis

Objetivo: Averiguar qual o papel desempenhado pelas dimensões ósseas da pelve em relação à gênese do prolapso de órgãos pélvicos por meio de publicações dos últimos quinze anos. Métodos: Trata-se de uma revisão sistemática de estudos ob- servacionais para avaliação de risco e prognóstico por meio de um levantamento bibliográfico virtual de artigos científicos publicados em revistas digitais entre os anos 2007 e 2022, nas bases de dados PubMed, BVS e ScienceDirect. Resultados: Uma área pélvica anterior mais ampla e um maior diâmetro interespinhoso foram caracterizados como possíveis causas para prolapso de órgãos pélvicos. A maior parte dos estudos contou com mensurações ósseas diversificadas, nas quais as demais dimensões não apresentaram significância estatística. Conclusão: Os estu- dos avaliados nesta revisão sugerem uma nova medida do assoalho pélvico rela- cionada a mulheres com prolapso, com apresentação de uma maior área anterior, em grande parte influenciada pelo diâmetro interespinhoso, o qual leva a um au- mento da carga sobre o assoalho pélvico. Porém, ainda assim, urge a necessidade de mais estudos para corroborar nossos achados.

Objective: To investigate the role played by the bone dimensions of the pelvis in relation to the genesis of pelvic organ prolapses through publications from the last fifteen years. Methods: This is a systematic review of obser- vational studies for risk assessment and prognosis through a virtual bibliographic survey of scientific articles published in digital journals between 2007 and 2022, in PubMed, BVS and ScienceDirect databases. Results: A wider anterior pelvic area and a larger interspinous diameter were characterized as possible causes for pelvic organ prolapses. Most of the studies have diversified bone measurements, in which the other dimensions weren't statistically significant. Conclusion: The studies evaluated in this review suggest a new measure- ment of the pelvic floor related to women with prolapse, with a larger anterior area, largely influenced by the interspinous diameter, which leads to an increased load on the pelvic floor. However, even so, there is an urgent need for further studies to corroborate our findings.

A comparative study of visual assessment between dry bone, 2-dimensional photograph, and deep learning methods in sex classification on the auricular area of the os coxae in a Thai population / Un estudio comparativo de la evaluación visual entre el hueso seco, la fotografía bidimensional y los métodos de aprendizaje profundo en la clasificación del sexo en el área auricular del hueso coxal en una población tailandesa

SUMMARY: Sex assessment is an important process in forensic identification. A pelvis is the best skeletal element for identifying sexes due to its sexually dimorphic morphology. This study aimed to compare the accuracy of the visual assessment in dry bones as well as 2D images and to test the accuracy of using a deep convolutional neural network (GoogLeNet) for increasing the performance of a sex determination tool in a Thai population. The total samples consisted of 250 left os coxa that were divided into 200 as a 'training' group (100 females, 100 males) and 50 as a 'test' group. In this study, we observed the auricular area, both hands-on and photographically, for visual assessment and classified the images using GoogLeNet. The intra-inter observer reliabilities were tested for each visual assessment method. Additionally, the validation and test accuracies were 85, 72 percent and 79.5, 60 percent, for dry bone and 2D image methods, respectively. The intra- and inter-observer reliabilities showed moderate agreement (Kappa = 0.54 - 0.67) for both visual assessments. The deep convolutional neural network method showed high accuracy for both validation and test sets (93.33 percent and 88 percent, respectively). Deep learning performed better in classifying sexes from auricular area images than other visual assessment methods. This study suggests that deep learning has advantages in terms of sex classification in Thai samples.

RESUMEN: La evaluación del sexo es un proceso importante en la identificación forense. La pelvis es el mejor elemento esquelético para identificar sexos debido a su morfología sexualmente dimórfica. Este estudio tuvo como objetivo comparar la precisión de la evaluación visual en huesos secos, así como imágenes 2D y probar la precisión del uso de una red neuronal convolucional profunda (GoogLeNet) para aumentar el rendimiento de una herramienta de determinación de sexo en una población tailandesa. Las muestras consistieron en 250 huesos coxales izquierdos, los que fueron dividi- das de la siguiente manera: 200 como un grupo de "entrenamiento" (100 mujeres, 100 hombres) y 50 como un grupo de "prueba". En este estudio, observamos el área auricular, tanto de forma práctica como fotográfica, para una evaluación visual y clasificamos las imágenes utilizando GoogLeNet. Se analizó la confiabilidad intra-interobservador para cada método de evaluación visual. Además, las precisiones de validación y prueba fueron del 85, 72 por ciento y 79,5, 60 por ciento, para los métodos de hueso seco y de imágenes 2D, respectivamente. Las confiabilidades intra e interobservador mostraron un acuerdo moderado (Kappa = 0.54 - 0.67) para ambas evaluaciones visuales. El método de red neuronal convolucional profunda mostró una alta precisión tanto para la validación como para los conjuntos de prueba (93,33 por ciento y 88 por ciento, respectivamente). El aprendizaje se desempeñó mejor en la clasificación de sexos a partir de imágenes del área auricular que otros métodos de evaluación visual. Este estudio sugiere que el aprendizaje profundo tiene ventajas en términos de clasificación por sexo en muestras tailandesas.

Pelvic incidence is not associated with the development of hip osteoarthritis.

AIMS: Pelvic incidence (PI) is considered an important anatomical parameter for determining the sagittal balance of the spine. The contribution of an abnormal PI to hip osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the relationship between PI and hip OA, and the difference in PI between hip OA without anatomical abnormalities (primary OA) and hip OA with developmental dysplasia of the hip (DDH-OA). METHODS: In this study, 100 patients each of primary OA, DDH-OA, and control subjects with no history of hip disease were included. CT images were used to measure PI, sagittal femoral head coverage, α angle, and acetabular anteversion. PI was also subdivided into three categories: high PI (larger than 64.0°), medium PI (42.0° to 64.0°), and low PI (less than 42.0°). The anterior centre edge angles, posterior centre edge angles, and total sagittal femoral head coverage were measured. The correlations between PI and sagittal femoral head coverage, α angle, and acetabular anteversion were examined. RESULTS: No significant difference in PI was observed between the three groups. There was no significant difference between the groups in terms of the category distribution of PI. The DDH-OA group had lower mean sagittal femoral head coverage than the other groups. There were no significant correlations between PI and other anatomical factors, including sagittal femoral head coverage, α angle, and acetabular anteversion. CONCLUSION: No associations were found between mean PI values or PI categories and hip OA. Furthermore, there was no difference in PI between patients with primary OA and DDH-OA. From our evaluation, we found no evidence of PI being an independent factor associated with the development of hip OA. Cite this article: Bone Joint J 2021;103-B(11):1656-1661.

Development of a three-dimensional computer model of the canine pelvic limb including cruciate ligaments to simulate movement.

Gait analysis as subjective visual assessment forms the foundation of the veterinarian's lameness examination. Pelvic limb lameness is frequently seen in dogs and the stifle joint with its cruciate ligaments, is a main cause of lameness due to cruciate ligament deficiency. In this study, we developed an open-source three-dimensional musculoskeletal pelvic limb model of a 30 kg Labrador Retriever including cruciate ligaments, simulating the gait cycle of the walking movement with the open-source programs NMSBuilder (Institutio Ortopedico Rizzoli, Bologna, Italy) and OpenSim (National Center for Simulation in Rehabilitation Research (NCSRR), Stanford, CA, USA). The computer model generated muscle activations based on motion data. The computed activations were similar to experimental electromyogram data. Highest joint torque was in extension/flexion in the stifle joint at 54 Nm at 14% of the gait cycle with cruciate ligaments. Highest stifle joint reaction force was 408 N at 16% of the gait cycle and was reduced after adding cruciate ligaments. Especially the cranial cruciate ligament loads up to 102 N (34% body weight). Cranial cruciate ligament forces increase with stifle extension and decrease with stifle flexion. On the contrary, the caudal cruciate ligament loads up to 27 N (9% body weight) during the swing phase with a flexed stifle joint. The model was validated with electromyogram data. The model's predictions are plausible because joint torques and forces match the applied ground reaction forces in curve progression and in timing. This model forms a basis for further investigations into stifle surgery after cruciate ligament deficiency.

Evaluation of margins in pelvic lymph nodes and prostate radiotherapy and the impact of bladder and rectum on prostate position.

PURPOSE: The aims of this study were: determination of the CTV to PTV margins for prostate and pelvic lymph nodes. Investigation of the impact of registration modality (pelvic bones or prostate) on the CTV to PTV margins of pelvic lymph nodes. Investigation of the variations of bladder and rectum over the treatment course. Investigation of the impact of bladder and rectum variations on prostate position. PATIENTS AND METHODS: This study included 15 patients treated for prostate adenocarcinoma. Daily kilo voltage images and weekly CBCT scans were performed to assess prostate displacements and common and external iliac vessels motion. These data was used to calculate the CTV to PTV margins using Van Herk equation in the setting of a daily bone registration. We also compared the CTV to PTV margins of pelvic lymph nodes according to registration method; based on pelvic bone or prostate. We delineated bladder and rectum on all CBCT scans to assess their variations over treatment course at 4 anatomic levels [1.5cm above pubic bone (PB), superior edge, mid- and inferior edge of PB]. RESULTS: Using Van Herk equation, the prostate CTV to PTV margins (bone registration) were 8.03mm, 5.42mm and 8.73mm in AP, ML and SI direction with more than 97% of prostate displacements were less than 5mm. The CTV to PTV margins ranged from 3.12mm to 3.25mm for external iliac vessels and from 3.12mm to 4.18mm for common iliac vessels. Compared to registration based on prostate alignment, bone registration resulted in an important reduction of the CTV to PTV margins up to 54.3% for external iliac vessels and up to 39.6% for common iliac vessels. There was no significant variation of the mean bladder volume over the treatment course. There was a significant variation of the mean rectal volume before and after the third week of treatment. After the third week, the mean rectal volume seemed to be stable. The uni- and multivariate analysis identified the anterior wall of rectum as independent factor acting on prostate motion in AP direction at 2 levels (superior edge of, mid PB). The right rectal wall influenced the prostate motion in ML direction at inferior edge of PB. The bladder volume tends toward significance as factor acting on prostate motion in AP direction. CONCLUSIONS: We recommend CTV to PTV margins of 8mm, 6mm and 9mm in AP, ML and SI directions for prostate. And, we suggest 4mm and 5mm for external and common iliac vessels respectively. We also prefer registration based on bony landmarks to minimize bowel irradiation. More CBCT scans should be performed during the first 3weeks and especially the first week to check rectum volume.

Relationship of aortic bifurcation with sacropelvic anatomy: Application to anterior lumbar interbody fusion.

INTRODUCTION: Various sacropelvic parameters such as the pelvic Incidence (PI) are used to predict ideal lumbar lordosis and aid surgical planning. The objective of this study was to establish the relationship between the location of the aortic bifurcation from the sacral promontory and sacropelvic measures including the PI. MATERIALS AND METHODS: One hundred sixty five computed tomography (CT) scans obtained for major trauma including the entire spine were identified. Sacropelvic parameters including PI, sacral anatomic orientation, pelvic thickness (PTH), and sacral table angle were measured. Aortic bifurcation was identified on sagittal and coronal imaging and the distance from the sacral promontory (bifurcation-promontory distance [BPD]) measured (mm). RESULTS: Mean age of the cohort was 44.3 years (SD 18.5; range 16-88 years); 61.8% male. The mean PI was 49.2° (SD 10.2°; range 30°-80°). The mean BPD was 66.4 mm (SD 13.1 mm; range 38.3-100 mm). In the majority, the bifurcation was at the level of the L4 vertebral body (72.7%). Only age (r = -.389; p < .0001) and PTH (r = .172; p = .027) correlated with the BPD to a significant degree. PI did not correlate with BPD (r = .061; p = .435). Linear regression analysis provided the following predictive equation: BPD = 34.3 mm + 0.30 × PTH. CONCLUSION: This study demonstrates a lack of any meaningful correlation between sagittal pelvic parameters and the distance of the aortic bifurcation from the sacral promontory. Surgical planning for fusion surgery in the lumbar spine should include assessment of spinopelvic parameters and if anterior access to the lumbar disc(s) necessary, vascular anatomy should be carefully assessed independent of these measures.

Is there a correlation between fragility fractures of the pelvis (FFP) and the morphology of the true pelvis in geriatric patients?

PURPOSE: There has been no prior study to demonstrate the relationship between the occurrence of fragility fractures of the pelvis and its morphology. The aim of this study was to investigate the effect of pelvic morphology on fragility fractures of the pelvis caused by low-energy trauma in elderly female patients. MATERIALS AND METHODS: As a normal pelvis group, 643 female patients over 65 years of age who underwent pelvic CT were collected. Using three-dimensional multiplanar reconstruction (3D-MPR) function of RadiAnt software, the DT (diameter of transverse true pelvis)/DS (diameter of sagittal true pelvis) values of normal pelvis were measured. Sorted in ascending order, the mean DT/DS value of normal pelvis was 1.13 ± 0.09. The values corresponding to the 25th percentile and the 75th percentile were 1.06 and 1.18, respectively. We arbitrarily named DT/DS values of 1.06 or less corresponding to lower than 25th percentile as 'Circle types', and DT/DS values of 1.18 or higher corresponding to higher than 75th percentile as 'Ellipse types'. Total of 76 female patients over 65 years of age who underwent 3D reconstructions of pelvic CT scans with fragility fractures of the pelvis, who fell into the criteria corresponding to FFP classification type II, were studied separately. Of the 76 female FFPs, two were FFP type IIa, 32 were FFP type IIb, and 42 were FFP type IIc. Their DT/DS was measured. RESULTS: Based on the above mentioned criteria, we classified the pelvis shape of 76 patients with fragility fracture of the pelvis type II. 33 patients (43.4%) were classified as circle types and eight patients (10.5%) were classified as ellipse types. The odds ratio of "circle type" for fragility fractures of pelvis type II was 4.1. CONCLUSION: With digital reconstruction and 3D measurement of normal adult pelvic CT scans, this study obtained a series of DT/DS values describing the shape of true pelvises. Circle-type true pelvis was found to be more common in patients with fragility fracture of the pelvis type II.

Automatic Characterization of Pelvic and Sacral Measures from 200 Subjects.

BACKGROUND: An understanding of pelvic and acetabular morphology and orientation is required for accurate surgical reconstruction of the hip and spine, as well for component placement in a total hip arthroplasty. Our objectives were to develop an automated system for measuring pelvic and sacral orientations utilizing computed tomographic (CT) scans and to characterize these measures across 200 asymptomatic subjects. METHODS: An automated feature recognition algorithm was created to identify acetabular and pelvic orientation across 200 scans generated for non-musculoskeletal conditions. Three-dimensional models were generated from CT data to serve as inputs to the algorithm. Acetabular orientation was defined by comparing a plane fit to the acetabular rim with the anterior pelvic plane. Pelvic inclination, pelvic tilt, and sacral slope were defined as the angles between landmarks identified across the pelvis: pubic tubercles, acetabular center, left and right anterior superior iliac spines, and sacral plate. RESULTS: The mean sacral slope was 36.49°, the mean pelvic tilt was 15.60°, and the mean pelvic incidence was 52.05°. The mean sacropubic angle was 32.48° and the mean pelvic-Lewinnek angle was 8.93°. Significant differences between male and female subjects were observed in the sacral slope (mean difference, 4.72°; p < 0.05), pelvic tilt α (mean difference, 4.17°; p < 0.05), pelvic tilt γ (mean difference, 3.06°; p < 0.05), and the pelvic-Lewinnek angle (mean difference, 1.76°; p < 0.05). The comparison of acetabular orientation measures with those in a prior study of the same cohort yielded intraclass correlation coefficients (ICCs) all above 0.97. The validation of sacral orientation via manual measurement also yielded ICC values all at or above 0.97. CONCLUSIONS: Our algorithm showed a high degree of consistency in acetabular orientation measures with respect to a prior study of the same cohort. The measures of pelvic orientation were found to be accurate and reliable when compared with manual measurements of the same data set. All measurements of pelvic orientation were consistent with the means reported in the literature. CLINICAL RELEVANCE: An accurate and reproducible, automated technique for determining pelvic and acetabular orientation provides a way to characterize these measures as an aid in clinical diagnosis and preoperative planning.

Morphometric, anatomic and radiographic study of bone of the pelvic limb of endangered Patagonian huemul deer (Hippocamelus bisulcus) / Estudio morfométrico, anatómico y radiográfico de los huesos del miembro pélvico del huemul patagónico en peligro de extinción (Hippocamelus bisulcus)

Currently, the Patagonian huemul (Hippocamelus bisulcus) is endangered. Anatomical studies focused on understanding the anatomy of the deer most threatened by extinction in South America is a challenge for anatomists, veterinarians and biologists. Research carried out for its conservation has focused mainly on its ecology and pathology, leaving gaps in anatomical knowledge, which is basic and important for a comprehensive understanding of this species. Gross anatomy and radiography of the skeleton of the pelvic limb was performed in three adult Patagonian huemul. Bone specimens of three skeletally mature Patagonian huemul deer were used for gross osteological and radiographic studies. This study was conducted to reveal the morphometric and morphological features of the ossa membri pelvini of the Patagonian huemul. The main findings suggest the presence of powerful extensor muscles in the coxofemoral, femorotibial and tarsal joints, useful during walking, jogging and propulsion in deer. In general, the MNF of Patagonian huemul differ in position with respect to domestic ungulates. In addition, the presence of a notch or obturator canal was observed, with variability in morphology and development among the specimens.

Actualmente, el Huemul Patagónico (Hippocamelus bisulcus) está en peligro de extinción. Los estudios morfológicos centrados en comprender su anatomía han sido un desafío para morfólogos, veterinarios y biólogos. Investigaciones enfocadas en su conservación, se han centrado principalmente en su ecología, patología y en la descripción de sus principales agentes infecciosos, dejando vacíos en el conocimiento anatómico básico, y por ende, su comprensión morfofisiológica. El objetivo de este estudio fue describir la anatomía, morfometría y radiología macroscópica normal y detallada del ossa membri pelvini en tres especímenes de Huemul Patagónico, incluida una interpretación funcional como referencia para uso clínico y conservacionista, investigación biomédica y fines de enseñanza. Los principales hallazgos sugieren la presencia de potentes músculos extensores en las articulaciones coxofemoral, femorotibial y tarsal, útiles durante la marcha, el trote y la propulsión en los ciervos. En general, los forámenes nutricios principales del Huemul patagónico difieren en posición con respecto a los ungulados domésticos. Además, se observó la presencia de una muesca o canal obturador, con variabilidad morfológica y de desarrollo entre los especímenes.

A comparative study of sagittal spinal-pelvic parameters between patients with adolescent idiopathic scoliosis and healthy controls / Un estudio comparativo de los parámetros sagitales de la columna vertebral-pélvic entre pacientes adolescentes con escoliosis idiopática y controles sanos

This study aimed to investigate the sagittal spinal-pelvic morphological changes, as well as the relationship between pelvic anatomical changes and the spinal-pelvic plane in patients with adolescent idiopathic scoliosis (AIS), in order to provide guidelines for orthopedic surgery in AIS. X-ray data were collected for retrospective analysis from 30 patients diagnosed as AIS in the Departments of Radiology at the Second Affiliated Hospital of Inner Mongolia Medical University and the Inner Mongolia International Mongolian Medical Hospital from April 2014 to November 2018, along with 30 normal adolescents as control. Pelvic parameters, including pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS), a spinal parameter, lumbar lordosis (LL), and anatomical parameters, including sacral width (SW) and femoral head- sacrum distance (FH-S), were measured. The spinal-pelvic parameters were compared between AIS patients and normal controls and also between male and female AIS patients. Pearson correlation was performed to analyze correlation between spinal-pelvic parameters and between spinal-pelvic parameters and anatomical parameters in both AIS patients and normal controls. PT was significantly lower in AIS patients than in normal controls (P < 0.05), whereas no significant difference was found in the other spinal-pelvic parameters, i. e. , LL, PI, and SS. There was a significant difference in PT between sexes in AIS patients. SS was significantly correlated with LL in EIA patients (P < 0.05, r > 0.5). SS was significantly correlated with LL and PI, and PT with LL, PI, and SS in normal controls (all P < 0.05), and there was no significant correlation between the other sagittal spinal-pelvic parameters (P > 0.05). FH-S was significantly correlated with LL, PI, SS, and PT in AIS patients (all P < 0.05). AIS affects some of the sagittal spinalpelvic parameters and anatomical parameters. In AIS, there is a significant correlation between the spinal-pelvic parameters, and the anatomical parameter is significantly correlated with multiple spinal-pelvic parameters.

Este estudio tuvo como objetivo investigar los cambios morfológicos sagitales de la columna vertebral-pélvica, así como la relación entre los cambios anatómicos pélvicos y el plano espinal-pélvico en pacientes con escoliosis idiopática adolescente (EIA), con el fin de proporcionar pautas para la cirugía ortopédica en AIS. Se obtuvieron los datos de rayos X para el análisis retrospectivo de 30 pacientes diagnosticados como EIA en los Departamentos de Radiología del hospital Second Affiliated Hospital of Inner Mongolia Medical University y el hospital Inner Mongolia International Mongolian Medical Hospital, desde abril de 2014 hasta noviembre del 2018, junto con 30 adolescentes normales como control. Se midieron los parámetros pélvicos, que incluyeron incidencia pélvica (IP), inclinación pélvica (P) y pendiente sacra (PS), un parámetro espinal, lordosis lumbar (LL) y parámetros anatómicos, que incluyeron el ancho sacro (AS) y la distancia del sacro cabeza femoral (FH-S). Los parámetros espinalpélvicos se compararon entre los pacientes con EIA y los controles normales, como también entre pacientes con EIA masculinos y femeninos. La correlación de Pearson se realizó para analizar la correlación entre los parámetros espinal-pélvicos y entre los parámetros espinal-pélvicos y los parámetros anatómicos tanto en pacientes con EIA como en controles normales. PT fue significativamente menor en pacientes con EIA que en los controles normales (P <0,05), mientras que no se encontraron diferencias significativas en los otros parámetros espinal-pélvicos, i. mi. , LL, PI y SS. Hubo una diferencia significativa en PT en pacientes de ambos sexos con EIA. SS se correlacionó significativamente con LL en pacientes con EIA (P <0,05, r> 0,5). SS se correlacionó significativamente con LL y PI, y PT con LL, PI y SS en controles normales (todos P <0,05), y no hubo correlación significativa entre los otros parámetros sagitales de la columna vertebral-pélvica (P> 0,05) FH-S se correlacionó significativamente con LL, PI, SS y PT en pacientes con EIA (todos P <0,05). EIA afecta algunos de los parámetros sagitales de la columna vertebral-pélvica y los parámetros anatómicos. En EIA, existe una correlación significativa entre los parámetros espinal-pélvicos, y el parámetro anatómico se correlaciona significativamente con múltiples parámetros espinales-pélvicos.

Pelvic Obliquity Correction in Distraction-Based Growth Friendly Implants.

DESIGN: Multicenter retrospective review. OBJECTIVE: To evaluate radiographic outcomes and complication rates of patients treated with distraction based implants and pelvic fixation with either screws (sacral-alar-iliac [SAI] screws or iliac screws) or hooks (S hook iliac fixation). SUMMARY OF BACKGROUND DATA: Multiple options exist for pelvic fixation in distraction-based growing rod systems; however, limited comparative data are available. METHODS: Early-onset scoliosis (EOS) patients of all diagnoses with distraction-based implants that had pelvic fixation from 2000 to 2013 were reviewed from two EOS multicenter databases. Patients were divided into two groups by type of pelvic fixation: (1) screw group (SAI screws or iliac screws) or (2) S hooks. Exclusion criteria were as follows: index instrumentation ≥10 years old and follow up <2 years. A total of 153 patients met the inclusion criteria. Mean age at index surgery was 6.1 years (range 1.0-9.9 years) and mean follow-up was 4.9 years. RESULTS: Pelvic fixation in the 153 patients was as follows: screw group = 42 and S hook group = 111. When comparing patients with >20° of initial pelvic obliquity, the screw group had significantly more correction; mean 26° ± 13° for the screw group versus mean 17° ± 7° in the S hook group (p = .039). There was no significant difference in change in T1-S1 length (40 vs. 39 mm, p = .89) or correction of Cobb angle (30° vs. 24°, p = .24). The total complication rate for the screw group was 14% (6/42) versus 25% (28/111) in the S hook group, though this did not achieve significance (p = .25). The most common complications were device migration (13), implant failure (8), and implant prominence (4) for S hooks and implant failure (3), implant prominence (2), and device migration (1) for the screw group. CONCLUSION: In distraction-based growth-friendly constructs, pelvic fixation with screws achieved better correction of pelvic obliquity than S hooks. Complications were almost twice as common with S hooks than screws, though this did not reach statistical significance.

The Influence of Pelvic Tilt on the Anteversion Angle of the Acetabular Prosthesis.

The concept of the "safe area" of the acetabular prosthesis has a long history and has been recognized by many scholars. It is generally believed that postoperative hip dislocation rate is low, when the acetabular anteversion angle is placed in the range of 15° ± 10°. Despite this, hip dislocation is a common complication after total hip arthroplasty. In recent years, more and more scholars have paid attention to the influence of pelvic tilt on the acetabular anteversion angle. The concept of acetabular anteversion changes as the pelvic tilt changes, and is challenging the traditional acetabular prosthesis "safe area." This study summarized the potential influencing factors of pelvic tilt and discussed the influence of the phenomenon on the anteversion angle of total hip arthroplasty (THA) acetabular prosthesis based on the literature review. We conclude that from the supine position to standing, followed by sitting, the pelvis tends to move backward. Pelvic sagittal activity, lumbar disease (ankylosing spondylitis), lumbar fusion (lumbar fusion, spine-pelvic fusion), and other factors related to the tilt are THA risk factors for postoperative dislocation and revision. With the change of body position, the degree of acetabular anteversion is directly related to the degree of pelvic tilt. The acetabular anteversion varies greatly, which leads to increased hip prosthesis wear and even hip dislocation. The lateral X-ray of the spine and pelvis is recommended in supine, standing, and sitting positions before THA. In addition, the pelvic tilt should be regarded as a reference of the acetabular prosthesis in the preoperative planning of THA.

Sagittal balance of the spine.

The static sagittal balance of the normal spine is a physiological alignment of the spine in the most efficient manner by the muscular forces. During gait, this balance is constantly thwarted by single-foot support. This analysis involves the study of parameters which are now well defined. The pelvic incidence is constant, and the sacral slope and the pelvic tilt are positional. The cervical parameters are the upper (O-C2) and lower cervical curvatures (C2-C7), the C7 slope, the spino-cranial angle and the vertical cervical offset. At the thoracic and lumbar level, they are, respectively, kyphosis and lordosis. The OD-HA (odontoid hip axis) angle is the most efficient parameter to analyse the global balance. The average values of these parameters are reported with the new 3D measurements by Le Huec et al. The relationship between these different parameters was analysed, and Roussouly proposed his classification of the different spine shape. Ageing makes it possible to show compensation mechanisms at three levels: spinal, pelvic and lower limbs. Understanding these different data allows for better planning of the surgical management of the patients. Global evaluation of the entire spine and the measurement of the aforementioned parameters allow to determine the extent of the correction to be performed during surgery. Taking these parameters into account also enables us to understand the complications involved in this type of surgery: transitional syndromes or junctional syndromes. Integration of these parameters into the study of gait is an area still under investigation. These slides can be retrieved under Electronic Supplementary Material .

Evaluation of anatomical pelvic parameters between normal, healthy men and women using three-dimensional computed tomography: a cross-sectional study of sex-specific and age-specific differences.

BACKGROUND: Sagittal spinal balance and standing posture are affected by pelvic morphology, especially pelvic incidence (PI). However, it is not difficult to identify the hip center because of overlap of the pelvis, image contrast, and soft tissue artifacts. Measurements of PI are not always suitable in all patients, especially those with osteoarthritis of the hip joint whose femoral head is nonspherical, subluxed, or dislocated. We measured PI, pelvic tilt (PT), and sacral slope (SS) as anatomical parameters using a novel three-dimensional measurement in order to compare the pelvic morphology between normal, healthy men and women. METHODS: In this cross-sectional study, we evaluated 108 Japanese subjects (55 men, 53 women) without low back or knee pain. We used the three-dimensional pelvis model adjusted to the anterior pelvic plane and measured the pelvic parameters. The subjects were stratified by age (< 50 versus ≥ 50 years) and sex. Intraobserver and interobserver reliabilities were calculated with intraclass correlation coefficients. RESULTS: There was no significant difference in PI, anatomical-PT, and anatomical-SS between sexes. There was a strong correlation between PI and anatomical-SS in men and women (R = 0.790 and 0.715, respectively). Values of anatomical-PT were lower, and values of anatomical-SS were greater among older subjects than among younger subjects; the value of PI was similar between younger and older subjects. Intraobserver and interobserver mean absolute differences were about 2 mm and 2°, respectively; the intraclass correlation coefficient was > 0.87. CONCLUSIONS: We found a strong correlation between PI and anatomical-SS in men and women. This novel measurement concept may be useful to estimate PI from anatomical-SS because the measurements of PI are not always suitable in all patients, especially those with osteoarthritis of the hip joint whose femoral head is not spherical or whose femoral head is subluxed or dislocated. This is the first report to describe the relationship between PI, anatomical-PT, and anatomical-SS as morphologic parameters with a high interclass correlation coefficient for intraobserver and interobserver reliabilities.

Predictive formula of ideal lumbar lordosis and lower lumbar lordosis determined by individual pelvic incidence in asymptomatic elderly population.

PURPOSE: This study aimed to obtain reference values of lumbar lordosis (LL) and lower LL (LLL) from normal asymptomatic groups, determine the relationship between them and pelvic incidence (PI), and establish the predictive formula for ideal LLL in the elderly Korean population. METHODS: Standing plain lateral radiographs of the whole spine, including the pelvis, were analyzed in asymptomatic adult male volunteers without back pain or prior surgery involving the spine or lower extremity. Volunteers with scoliosis, spondylolisthesis, segmental disk space narrowing, and/or compression fractures in the radiographs were excluded. The following parameters were measured: LL, LLL, and pelvic parameters including PI. The values of PI-LL and PI-LLL were calculated, and the formula using stepwise multiple regression analysis was made. A P value of < 0.05 was considered statistically significant. RESULTS: The study participants included 150 volunteers. All were male participants with an average age of 64.1 ± 6.4. The average value of height, weight, and body mass index was 167.0 ± 5.5 cm, 67.3 ± 9.8 kg, and 24.1 ± 3.1 kg/m2, respectively. The average LL was - 57.5° ± 9.0°, LLL was - 41.7° ± 7.0°, and PI was 48.6° ± 8.6°. The formula was established as follows: PI-LL = 0.38 × PI - 27.61 (R2 = 0.172), PI-LLL = 0.77 × PI - 28.69 (R2 = 0.516), ideal LL = 0.62 × PI + 27.61 (R2 = 0.348), and ideal LLL = 0.225 × PI + 28.63 (R2 = 0.083). CONCLUSIONS: The ideal values of PI-LL and PI-LLL were inconsistent, and they have a positive correlation with PI in asymptomatic elderly population. Our data would be helpful as a normal reference value of ideal LL and LLL according to PI. These slides can be retrieved under Electronic Supplementary Material.

Three-dimensional analysis of acetabular orientation using a semi-automated algorithm.

Understanding the morphology of the acetabulum is necessary for preoperative evaluation in hip surgery. The purpose of this study was to (1) establish a novel method for measuring three-dimensional (3D) acetabular orientation, (2) quantify the reliability of this method, and (3) describe relevant characteristics of three-dimensional (3D) acetabular orientation among normal Asian subjects. Computed tomography (CT) scans of the pelvis that had been performed for suspected non-musculoskeletal conditions were obtained from 200 subjects (60 males, 140 females). A novel method was developed to measure 3D acetabular orientation with a semi-automatically determined pelvic coordinate system based on the anterior pelvic plane (APP). To quantify the robustness of our method, we analyzed the results obtained from 20 patients at different times and with different raters and pelvic poses in the same CT volume. To determine morphological differences of the acetabulum by age and sex, we analyzed the parameters of 200 CT volumes. Each intraclass correlation coefficient (ICC) values for intra- and inter-observer reliability were over 0.975 and 0.945, demonstrating high reliability. Furthermore, agreement between the angles determined from the original volume and the rotated volume was nearly perfect (ICCs > 0.956). Multiple linear regression analysis with age and sex as covariates indicated that acetabular inclination was not significantly associated with age (p = 0.687) or sex (p = 0.09). There was also no evidence that acetabular anteversion was associated with age (p = 0.383) or sex (p = 0.53). Our method showed excellent reliability for determining acetabular orientation, as it is robust, fast, and easily applicable to larger populations. In addition, the results of the analysis of acetabular orientation by age and sex can be used as a reference in various diagnostic procedures in orthopedics.

Pelvic incidence measurement using a computed tomography data-based three-dimensional pelvic model.

OBJECTIVES: To introduce a new method of pelvic incidence (PI) measurement based on three-dimensional (3D) pelvic models reconstructed from CT images and to report the normal distribution of PI in normal pelvic anatomy. METHODS: CT images of 320 subjects with normal pelvic anatomy who visited the Radiology Department between 2006 and 2017 were retrospectively selected and saved in Digital Imaging and Communications in Medicine (DICOM) format. A computerized method was employed to determine the bony landmarks required for the measurement of PI. To quantify the method's accuracy and reliability, the intraclass correlation coefficient (ICC) was calculated. A subgroup of 30 DICOM files was randomly selected to perform a validation study. Three independent testers performed all procedures. All measurements were performed twice independently by the three testers on all 10 subjects with an interval of 2 weeks. Independent samples t tests were used to identify statistically significant differences in the PI value between sexes. Pearson correlation coefficient was employed to determine the relationship between PI and age. RESULTS: PI measurement using the new method resulted in an excellent intraobserver reliability (0.9612, range 0.8917-0.9893; p < 0.001) and interobserver reliability (0.9867, range 0.9611-0.9964; p < 0.001). PI was significantly different between sexes, with larger PI in women (p = 0.019). PI was significantly larger in the 40-80-year age group (45.94 ± 9.08°) than the < 40-year age group (43.50 ± 7.39°). We did not find any linear correlation between PI and age in the male (r = 0.140, p = 0.105) or female subgroup (r = 0.119, p = 0.107). A weak correlation between PI and age overall was observed (r = 0.142, p = 0.011). CONCLUSION: Accurate PI measurement could be achieved by a CT data-based 3D pelvic model.

Evaluation of the correlation between prostatic displacement and rectal deformation using the Dice similarity coefficient of the rectum.

To estimate the relationship between the three-dimensional (3D) displacement error of the prostate and rectal deformation for reduction of deviation between the planned and treatment dose, using multiple acquisition planning CT (MPCT) and the Dice similarity coefficient (DSC) for rectal deformation for treatment of patients with prostate cancer. The 3D displacement error between the pelvic bone and a matching fiducial marker was calculated using MPCT in 24 patients who underwent prostate volumetric-modulated arc therapy for prostate cancer. We calculated the 3D displacement error between the pelvic bone and a matching fiducial marker on MPCT. The correlation of the 3D displacement error with the DSC of the rectum, calculated from MPCT images, was evaluated based on deformable image registration. The 3D displacement error of the prostate showed a slight correlation between MPCT and cone-beam computed tomography (adjusted r2 = 0.241). The 3D displacement error, based on the pelvic bone and a fiducial marker on MPCT images, showed a moderate correlation with the DSC of the rectum (adjusted r2 = 0.645) and was improved by a mean of 3.94 mm, based on MPCT, during the treatment period. The 3D displacement error on MPCT correlates with the 3D displacement error of daily cone-beam computed tomography; optimal selection of MPCT can potentially facilitate on-board setup of prostate patients to enable more accurate radiotherapy. The advance information of the 3D displacement error and rectal deformation is useful for optimal planning CT that can minimize the deviation between the planned dose and the treatment dose in patients receiving treatment for prostate cancer.

Symmetry Matching of the Medial Acetabular Surface-A Quantitative Analysis in View of Patient-Specific Implants.

OBJECTIVE: To quantify intrapelvic surface symmetry in reference to a preshaped suprapectineal acetabular implant. METHODS: In this cross-sectional study, an anatomically preshaped acetabular fracture implant was fitted on 3D surface models of 516 pelvises from a preexisting bone database using a software tool for automated implant fitting (SOMA, Stryker Orthopaedic Modeling and Analytics) of a CAD model of the implant. The distances between bone and the reference implant were measured at 2310 reference points for each hemipelvis. RESULTS: The average distance between the left hemipelvis and the plate was 1.98 mm (median, 10% percentile: 1.45, 90% percentile: 2.78) and 2.0 mm (median, 10% percentile: 1.45, 90% percentile: 2.92) between the right hemipelvis and the plate. There was no significant difference between the 2 hemipelvises (median absolute pairwise delta: 0.25 mm; 10% percentile: 0.04, 90% percentile: 0.82; Wilcoxon, P = 0.064). CONCLUSIONS: With regard to the periacetabular surface of the inner pelvis, the pelvis can be considered sufficiently symmetric for using the mirrored contralateral hemipelvis as a template for patient-specific implants in acetabular fracture fixation.

Variations in pelvic dimensions: An anatomical and computed tomography study.

The anterior pelvic plane (APP) is a useful anatomical reference with both clinical and research applications in orthopedic surgery and rehabilitation medicine. It is used as a marker for computer-assisted total hip replacement and image-guided assessment of the hip center in clinical gait analysis. Despite its common use, no published data exist on the variations in height and width in an adult population. The aim of this study was to determine the range of dimensions for the anterior pelvic plane found in the Scottish adult population. Thirty-five human cadavers and 100 pelvic computed tomography (CT) scans were examined. Pelvic height and width were measured, and the ratios were determined. The mean width and height for combined cadaver and CT pelves were found to be 238.0 mm (SD 20.1, range 188.3-273.8) and 92.7 mm (SD 10.5, range 71.2-114.7), respectively. The mean width-to-height ratio for all pelves was 2.59 (SD 0.31, range 1.73-3.50). There were no statistically significant differences in means between males and females. The variations of APP dimensions within an adult population are presented. These will be of value in the validation of algorithms for computer navigation and hip joint center calculation in total hip arthroplasty and gait analysis. Furthermore, differences in dimensions between cadaveric and CT measurements have been shown which may have implications for further research and the validity of reference data dependent on data-point acquisition. Clin. Anat. 31:981-987, 2018. © 2018 Wiley Periodicals, Inc.