Mechanism of sternotomy dehiscence

Casha, Aaron; Manche, Alexander; Gatt, Ruben; Duca, Edward; Gauci, Marilyn; Schembri-Wismayer, Pierre; Camilleri-Podesta, Marie-Therese; Grima, Joseph N.

doi:10.1093/icvts/ivu184

Cited by 33 publications

(31 citation statements)

References 20 publications

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“…An ellipsoid with coronal radius 12 cm, sagittal radius 11 cm, vertical height 21 cm, and thickness 2 cm was used to produce a finite element analysis (FEA) computer model. This model, based on published methods using the mean dimensions of seven rib cages that were statistically significantly similar to an ellipsoid with the above dimensions, mimicked the front and side of the chest above the widest point of the rib cage, the equator of the ellipsoid being equivalent to the widest part of the cage between the sixth and seventh ribs (Casha et al, ; Casha et al, ) (Fig. ).…”

Section: Methodsmentioning

confidence: 99%

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Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures

et al. 2015

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The human rib cage resembles a masonry dome in shape. Masonry domes have a particular construction that mimics stress distribution. Rib cortical thickness and bone density were analyzed to determine whether the morphology of the rib cage is sufficiently similar to a shell dome for internal rib structure to be predicted mathematically. A finite element analysis (FEA) simulation was used to measure stresses on the internal and external surfaces of a chest-shaped dome. Inner and outer rib cortical thickness and bone density were measured in the mid-axillary lines of seven cadaveric rib cages using computerized tomography scanning. Paired t tests and Pearson correlation were used to relate cortical thickness and bone density to stress. FEA modeling showed that the stress was 82% higher on the internal than the external surface, with a gradual decrease in internal and external wall stresses from the base to the apex. The inner cortex was more radio-dense, P < 0.001, and thicker, P < 0.001, than the outer cortex. Inner cortical thickness was related to internal stress, r = 0.94, P < 0.001, inner cortical bone density to internal stress, r = 0.87, P = 0.003, and outer cortical thickness to external stress, r = 0.65, P = 0.035. Mathematical models were developed relating internal and external cortical thicknesses and bone densities to rib level. The internal anatomical features of ribs, including the inner and outer cortical thicknesses and bone densities, are similar to the stress distribution in dome-shaped structures modeled using FEA computer simulations of a thick-walled dome pressure vessel. Fixation of rib fractures should include the stronger internal cortex.

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Section: Methodsmentioning

confidence: 99%

“…The chest resembles a hollow ellipsoid shell in shape (Casha et al, ) (Fig. ) and can also be considered as a load‐bearing shell structure, or dome, implying advantages of low weight and high strength (Huerta, ).…”

Section: Introductionmentioning

confidence: 99%

Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures

et al. 2015

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“…Intramuscular forces were calculated as the vectors of both circumferential and axial chest wall forces at right angles to the ribs at the mid-axillary line using a thin-wall FEA ellipsoid pressure vessel model with 12 cm coronal radius, 11 cm sagittal radius and 21 cm vertical height, following established procedures (Casha, 2014). The model assumed isotropy, with the chest wall modeled as a homogenous elastic material with properties chosen to correspond to the upper-bound limit defined by the rule of mixtures for a composite of matrix and fiber:…”

Section: Calculation Of Intramuscular Forcesmentioning

confidence: 99%

“…The chest wall has been modeled as a pressure vessel to obtain measurements of the rib forces at the mid‐axillary line using a validated model (Casha, ) (Fig. ).…”

Section: Introductionmentioning

confidence: 99%

External rib structure can be predicted using mathematical models: An anatomical study with application to understanding fractures and intercostal muscle function

et al. 2015

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As ribs adapt to stress like all bones, and the chest behaves as a pressure vessel, the effect of stress on the ribs can be determined by measuring rib height and thickness. Rib height and thickness (depth) were measured using CT scans of seven rib cages from anonymized cadavers. A Finite Element Analysis (FEA) model of a rib cage was constructed using a validated approach and used to calculate intramuscular forces as the vectors of both circumferential and axial chest wall forces at right angles to the ribs. Nonlinear quadratic models were used to relate rib height and rib thickness to rib level, and intercostal muscle force to vector stress. Intercostal muscle force was also related to vector stress using Pearson correlation. For comparison, rib height and thickness were measured on CT scans of children. Rib height increased with rib level, increasing by 13% between the 3rd and 7th rib levels, where the 7th/8th rib was the widest part or "equator" of the rib cage, P < 0.001 (t-test). Rib thickness showed a statistically significant 23% increase between the 3rd and 7th ribs, P = 0.004 (t-test). Intercostal muscle force was significantly related to vector stress, Pearson correlation r = 0.944, P = 0.005. The three nonlinear quadratic models developed all had statistically significant parameter estimates with P < 0.03. External rib morphology, in particular rib height and thickness, can be predicted using statistical mathematical models. Rib height is significantly related to the calculated intercostal muscle force, showing that environmental factors affect external rib morphology.

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“…1,2 The presence of significant complications of sternal bone healing after MS is rare but can be serious and lengthy. 3,4 Besides clinical examination, chest radiography (X-rays) and computer tomography are the standard of care for the analysis of sternal bone. [5][6][7] Sternal healing problems can cause typical clinical signs, such as sternal click and/or evidence of sternal instability on physical exam, coughing, or respiration.…”

Section: Introductionmentioning

confidence: 99%

Sternal Anomalies in Asymptomatic Patients after Median Sternotomy and Potential Influencing Factors

Biefer

Sündermann

Alkadhi

et al. 2017

Thorac cardiovasc Surg

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Mechanism of sternotomy dehiscence

Cited by 33 publications

References 20 publications

Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures

Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures

External rib structure can be predicted using mathematical models: An anatomical study with application to understanding fractures and intercostal muscle function

Sternal Anomalies in Asymptomatic Patients after Median Sternotomy and Potential Influencing Factors

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