scholarly journals The Retroacetabular Angle Determines the Safe Angle for Screw Placement in Posterior Acetabular Fracture Fixation

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Ayman M. A. Tadros ◽  
Thomas R. Oxland ◽  
Peter O’Brien

Introduction. A method for the determination of safe angles for screws placed in the posterior acetabular wall based on preoperative computed tomography (CT) is described. It defines a retroacetabular angle and determines its variation in the population. Methods. The retroacetabular angle is the angle between the retroacetabular surface and the tangent to the posterior acetabular articular surface. Screws placed through the marginal posterior wall at an angle equal to the retroacetabular angle are extraarticular. Medial screws can be placed at larger angles whose difference from the retroacetabular angle is defined as the allowance angles. CT scans of all patients with acetabular fractures treated in our institute between September 2002 to July 2007 were used to measure the retroacetabular angle and tangent. Results. Two hundred thirty one patients were included. The average (range) age was 42 (15–74) years. The average (range) retroacetabular angle was 39 (30–47) degrees. The average (range) retroacetabular tangent was 36 (30–45) mm. Conclusions. Placing the screws at an average (range) angle of 39 (33–47) degrees of anterior inclination with the retroacetabular surface makes them extraarticular. Angles for medial screws are larger. Safe angles can be calculated preoperatively with a computer program.

2019 ◽  
Vol 12 (S 01) ◽  
pp. S39-S44
Author(s):  
Michael Okoli ◽  
Kevin Lutsky ◽  
Michael Rivlin ◽  
Brian Katt ◽  
Pedro Beredjiklian

Abstract Introduction The purpose of this study is to determine the radiographic dimensions of the finger metacarpals and to compare these measurements with headless compression screws commonly used for fracture fixation. Materials and Methods We analyzed computed tomography (CT) scans of the index, long, ring, and small metacarpal bones and measured the metacarpal length, distance from the isthmus to the metacarpal head, and intramedullary diameter of the isthmus. Metacarpals with previous fractures or hardware were excluded. We compared these dimensions with the size of several commercially available headless screws used for intramedullary fixation. Results A total of 223 metacarpals from 57 patients were analyzed. The index metacarpal was the longest, averaging 67.6 mm in length. The mean distance from the most distal aspect of the metacarpal head to the isthmus was 40.3, 39.5, 34.4, and 31 mm for the index, long, ring, and small metacarpals, respectively. The narrowest diameter of the isthmus was a mean of 2.6, 2.7, 2.3, and 3 mm for the index, long, ring, and small metacarpals, respectively. Of 33 commercially available screws, only 27% percent reached the isthmus of the index metacarpal followed by 42, 48, and 58% in the long, ring, and small metacarpals, respectively. Conclusion The index and long metacarpals are at a particular risk of screw mismatch given their relatively long lengths and narrow isthmus diameters.


2020 ◽  
Vol 49 (1) ◽  
pp. 367-381
Author(s):  
Robel K. Gebre ◽  
Jukka Hirvasniemi ◽  
Iikka Lantto ◽  
Simo Saarakkala ◽  
Juhana Leppilahti ◽  
...  

AbstractThe incidence of low-energy acetabular fractures has increased. However, the structural factors for these fractures remain unclear. The objective of this study was to extract trabecular bone architecture and proximal femur geometry (PFG) measures from clinical computed tomography (CT) images to (1) identify possible structural risk factors of acetabular fractures, and (2) to discriminate fracture cases from controls using machine learning methods. CT images of 107 acetabular fracture subjects (25 females, 82 males) and 107 age-gender matched controls were examined. Three volumes of interest, one at the acetabulum and two at the femoral head, were extracted to calculate bone volume fraction (BV/TV), gray-level co-occurrence matrix and histogram of the gray values (GV). The PFG was defined by neck shaft angle and femoral neck axis length. Relationships between the variables were assessed by statistical mean comparisons and correlation analyses. Bayesian logistic regression and Elastic net machine learning models were implemented for classification. We found lower BV/TV at the femoral head (0.51 vs. 0.55, p = 0.012) and lower mean GV at both the acetabulum (98.81 vs. 115.33, p < 0.001) and femoral head (150.63 vs. 163.47, p = 0.005) of fracture subjects when compared to their matched controls. The trabeculae within the femoral heads of the acetabular fracture sides differed in structure, density and texture from the corresponding control sides of the fracture subjects. Moreover, the PFG and trabecular architectural variables, alone and in combination, were able to discriminate fracture cases from controls (area under the receiver operating characteristics curve 0.70 to 0.79). In conclusion, lower density in the acetabulum and femoral head with abnormal trabecular structure and texture at the femoral head, appear to be risk factors for low-energy acetabular fractures.


2019 ◽  
Vol 30 (6) ◽  
pp. 539-543
Author(s):  
Mahmoud Badran ◽  
Osama Farouk ◽  
Ayman Kamal ◽  
Hossam Abubeih ◽  
Mohamed Khaled

Orthopedics ◽  
2016 ◽  
Vol 39 (6) ◽  
pp. e1104-e1111 ◽  
Author(s):  
Swapnil B. Shah ◽  
Theodore T. Manson ◽  
Jason W. Nascone ◽  
Marcus F. Sciadini ◽  
Robert V. O'Toole

2017 ◽  
Vol 157 (4) ◽  
pp. 731-736
Author(s):  
Noel Ayoub ◽  
Andrew Thamboo ◽  
Peter H. Hwang ◽  
Evan S. Walgama

Objective A radioanatomic study of surgically relevant variations in the greater palatine canal (GPC) on computed tomography (CT) was performed to determine susceptibility during endoscopic endonasal procedures. Study Design Blinded radioanatomic analysis. Setting Tertiary university hospital. Subjects and Methods Fifty consecutive paranasal CT scans (100 sides) were analyzed. Measurements were standardized to landmarks such as the inferior turbinate (IT) and floor of the nasal cavity (FNC) to assess variability and vulnerability of the nerve. Measurements included (1) incidence of maxillary sinus pneumatization posterior to the GPC, (2) distance from the posterior wall of the maxillary sinus to the GPC at the IT and FNC, (3) width of bone containing the GPC, (4) incidence of medial GPC dehiscence, and (5) angle of the GPC extending from the IT to FNC. Results Ninety-one percent of maxillary sinuses were pneumatized posterior to the GPC. The distance from the posterior wall of the maxillary sinus to the GPC was 2.8 ± 1.7 mm (range, –2.3 to 5.9) at the posterior attachment of the IT and 4.1 ± 3.1 mm (range, –6.3 to 11.9) at the FNC. The width of bone containing the GPC was 3.3 ± 1.3 mm (range, 1-8.9), and the medial bony GPC was dehiscent in 38% of cases. In the sagittal plane, the angle of the GPC between the IT and the FNC was 31.9 ± 6.9 degrees (range, 10.8-45). Conclusion The GPC has considerable anatomic variability relative to important surgical landmarks in endoscopic procedures. Preoperative review of CTs to assess vulnerability may prevent postoperative complications.


2020 ◽  
Vol 7 (2) ◽  
pp. 76-80
Author(s):  
V. Alekseeva ◽  
V. Gargin

DETERMINATION OF THE STRUCTURE OF THE WALLS OF THE FRONTAL SINUS ACCORDING TO SPIRAL COMPUTED TOMOGRAPHY Alekseeva V., Gargin V. The anatomical structure of the frontal sinus is of key importance for the development of its inflammation and the development of complications with spread to neighboring organs and tissues (orbital phlegmon, brain abscesses, meningitis). The aim of our study was to compare the density and thickness of the bone tissue of the unchanged frontal sinus and in various forms of chronic inflammation. Materials and methods. We observed 121 patients with various forms of chronic frontal sinusitis: 56 with chronic hyperplastic (mucosal hyperplasia (up to 6 mm) and 33 patients with chronic purulent-polypous frontal sinusitis, manifested by a total and subtotal decrease in sinus pneumatization according to spiral computed tomography (SCT). 32 SCT samples were selected to form a comparison group without any abnormalities of the paranasal sinuses. Results. The maximum density typical for the lower wall of the frontal sinus under physiological conditions and was found to be 107.96 ± 201.64Hu, the minimum for the posterior wall in purulent-polypous frontal sinusitis was -103.74 ± 195.37Hu. The bone thickness both in the posterior region and in the region practically does not depend on the degree of the severity of pathological changes in it and is 1.0006 ± 0.538 mm, 0.91 ± 0.26 mm, 0.82 ± 0.169 mm under physiological conditions , with mucosal hyperplasia and with purulent-polypous frontal sinusitis in the posterior wall, respectively. In the region of the lower wall, 4.05 ± 2.04 mm, 2.32 ± 1.16 mm, and 4.002 ± 1.16 mm, respectively, according to the above order. Conclusion. It can be assumed that the larger the change in PNSs, the lower the bone density. This in turn affects the prediction of possible complications during surgical treatment of chronic frontal sinusitis. Key words: frontal sinus, computed tomography, bone thickness, bone density   Резюме. ВИЗНАЧЕННЯ МОРФОЛОГІЧНОЇ СТРУКТУРИ СТІНОК ЛОБНОЇ ПАЗУХИ ЗА ДОПОМОГОЮ СПІРАЛЬНОЇ КОМП'ЮТЕРНОЇ ТОМОГРАФІЇ Алєксєєва B.B., Гаргін B.B. Анатомічна будова лобної пазухи має ключове значення для виникнення запальних процесів та розвитку ускладнень із поширенням на сусідні органи та тканини (формування флегмони орбіти, абсцесів мозку, менінгіту). Метою нашого дослідження було порівняння щільності та товщини кісткової тканини лобної пазухи в фізіологічних умовах та при різних формах хронічного запального процесу. Матеріали та методи. Під спостереженням було 89 пацієнтів з різними формами хронічного фронтального синуситу: 56 - з хронічним гіперпластичним фронтальним синуситом (гіперплазією слизової оболонки до 6 мм) та 33 пацієнти з хронічним гнійно-поліпозним фронтальним синуситом, що при проведенні спіральної комп’ютерної томографії (СКТ) проявлявся тотальним і субтотальним зниженням пневматизації. Контрольна група - 32 СКТ людей з фізіологічним станом навколоносових пазух. Результати. Максимальна щільність кісткової тканини була визначена в області нижньої стінки лобної пазухи та становила - 107.96 ± 201.64 Hu, мінімальна - в області задньої стінки при гнійно-поліпозному лобному синуситі - -103.74 ± 195.37 Hu. Товщина кісток практично не залежала від ступеня виразності патологічних змін у ній і становить в області задньої стінки - 1.0006 ± 0.538 мм, 0.91 ± 0.26 мм, 0.82 ± 0.169 мм у фізіологічних умовах, при гіперплазії слизової оболонки і при гнійно-поліпозному фронтальному синуситі. В області нижньої стінки 4.05 ± 2.04 мм, 2.32 ± 1,16 мм та 4.002 ± 1.16 мм відповідно. Висновки. Можна припустити, що щільність кісткової тканини залежить від ступеня виразності патологічних змін в лобній пазусі. Це в свою чергу впливає на прогнозування розвитку ускладнень. Ключові слова: лобна пазуха, спіральна комп'ютерна томографія, товщина кісток, щільність кісток.   Резюме. ОПРЕДЕЛЕНИЕ МОРФОЛОГИЧЕСКОЙ СТРУКТУРЫ СТЕНОК ЛОБНОЙ ПАЗУХИ С ПОМОЩЬЮ СПИРАЛЬНОЙ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ Алексеева B.B., Гаргин B.B. Анатомическое строение лобной пазухи имеет ключевое значение для возникновения воспалительных процессов и развития осложнений с распространением на соседние органы и ткани (формирование флегмоны орбиты, абсцессов мозга, менингита). Целью нашего исследования было сравнение плотности и толщины костной ткани лобной пазухи в физиологических условиях и при различных формах хронического воспалительного процесса.Материалы и методы. Под наблюдением находилось 89 пациентов с различными формами хронического фронтального синусита: 56 - с хроническим гиперпластическим фронтальным синуситом (гиперплазией слизистой оболочки до 6 мм) и 33 пациента с хроническим гнойно-полипозным фронтальным синуситом, что при проведении спиральной компьютерной томографии (СКТ) проявлялся тотальным и субтотальным снижением пневматизации. Контрольная группа - 32 СКТ людей с физиологическим состоянием околоносовых пазух.Результаты. Максимальная плотность костной ткани была определена в области нижней стенки лобной пазухи в физиологических условиях и составила - 107.96 ± 201.64 Hu, минимальная - в области задней стенки при гнойно-полипозном лобном синусите - -103.74 ± 195.37 Hu. Толщина костей практически не зависила от степени выраженности патологических изменений в ней и составляла в области задней стенки - 1.0006 ± 0.538 мм, 0.91 ± 0.26 мм, 0.82 ± 0.169 мм в физиологических условиях, при гиперплазии слизистой оболочки и при гнойно-полипозном фронтальном синусите. В области нижней стенки 4.05 ± 2.04 мм, 2.32 ± 1.16 мм и 4.002 ± 1.16 мм, соответственно. Выводы. Можно предположить, что плотность костной ткани зависит от степени выраженности патологических изменений в лобной пазухе. Это в свою очередь влияет на прогнозирование возможности развития осложнений. Ключевые слова: лобная пазуха, спиральная компьютерная томография, толщина костей, плотность костей.


2000 ◽  
Vol 122 (5) ◽  
pp. 673-677 ◽  
Author(s):  
Andrew P. Lane ◽  
Robert A. Buckmire ◽  
Suresh K. Mukherji ◽  
Harold C. Pillsbury ◽  
Scott D. Meredith

Carcinomas originating in the retromolar trigone (RMT) are uncommon and characterized by early spread. Determination of mandibular invasion is significant for planning therapy and determining prognosis. For oral cavity cancers in general, CT is reasonably accurate in assessing bone invasion. However, there is a paucity of information specifically addressing the value of CT in the RMT. In this study, the records of patients with biopsy-proven RMT carcinomas treated between 1984 and 1998 were reviewed with attention to preoperative CT scans and histopathologic findings during surgery. Half of the patients who were treated with primary resection had mandibular invasion. Bone invasion was not identified radiographically in 27% of patients with preoperative CT scans. The sensitivity of CT for bone involvement in RMT cancers was 50%, with a negative predictive value of 61.1%. The positive predictive value was 91.1%. These findings suggest that CT is a useful, but potentially inaccurate, predictor of bone invasion in the RMT.


2000 ◽  
Vol 122 (5) ◽  
pp. 673-677 ◽  
Author(s):  
Andrew P. Lane ◽  
Robert A. Buckmire ◽  
Suresh K. Mukherji ◽  
Harold C. Pillsbury ◽  
Scott D. Meredith

Carcinomas originating in the retromolar trigone (RMT) are uncommon and characterized by early spread. Determination of mandibular invasion is significant for planning therapy and determining prognosis. For oral cavity cancers in general, CT is reasonably accurate in assessing bone invasion. However, there is a paucity of information specifically addressing the value of CT in the RMT. In this study, the records of patients with biopsy-proven RMT carcinomas treated between 1984 and 1998 were reviewed with attention to preoperative CT scans and histopathologic findings during surgery. Half of the patients who were treated with primary resection had mandibular invasion. Bone invasion was not identified radiographically in 27% of patients with preoperative CT scans. The sensitivity of CT for bone involvement in RMT cancers was 50%, with a negative predictive value of 61.1%. The positive predictive value was 91.1%. These findings suggest that CT is a useful, but potentially inaccurate, predictor of bone invasion in the RMT.


2019 ◽  
Vol 27 (3) ◽  
pp. 230949901985983 ◽  
Author(s):  
F Pease ◽  
AJ Ward ◽  
AJ Stevenson ◽  
JL Cunningham ◽  
O Sabri ◽  
...  

Stable, anatomical fixation of acetabular fractures gives the best chance of successful outcome, while penetration of the acetabular articular surface with screws is associated with poor outcomes. Spring plates are an alternative to interfragmentary lag screws when penetration is a concern. A mechanical study comparing fracture stability and construct stiffness of three fixation methods for posterior wall acetabular fractures with transverse comminutions was performed. The three fixation methods tested were a posterior wall rim plate, a posterior wall buttress plate with separate lag screws and a posterior wall plate with two spring plates. Nine samples were tested, three for each fixation method. Two-dimensional motion analysis was used to measure fracture fragment displacement and construct stiffness. After two 6000 cycle-loading protocols, to a maximum 1.5 kN, the mean fracture displacement was 0.154 mm for the rim plate model, 0.326 mm for the buttress plate and 0.254 mm for the spring plate model. Mean maximum displacement was significantly less for the rim plate fixation than the buttress plate ( p = 0.015) and spring plate fixation ( p = 0.02). The rim plate was the stiffest construct 10,962 N/mm, followed by the spring plate model 5637 N/mm and the buttress plate model 4882 N/mm. Based on data obtained in this study, where possible a rim plate with interfragmentary lag screws should be used for isolated posterior wall fractures as this is the stiffest and most stable construct. When this method is not possible, spring plate fixation is a safe and a superior alternative to a posterior buttress plate method.


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