| Objective: To study the3-9ribs and the geometry of rib-transverseprocess combined area among normal adults, and explore the CT measuringmethod of rib and rib-transverse process combined area, this paper providesgeometric morphometric parameters for anatomic plate design. Provide thebasis for flail chest patients and make the total thoracoscopic rib fracturefixation possible.Methods: Choose20patients(patients with chest CT scans in ourhospital from May2012to July,10male cases,10female cases; the Hannationality; height167cm-180cm; age16-58years old; average37years old),and exclude the traumatic and other diseases led to rib shape and densityanomalies. After having the general chest CT scan, make three-dimensionalimage of thoracic bone by using reconstruction techniques in the ADW4.4platform. Make the appropriate rotation, and observe the ribs and costalgroove running, then make sure the position of costal head、tubercle、costo-chondral junction（CCJ）and angulus custae. Finally, analyze andmeasure the geometric shape of the ribs and rib-transverse process combinedarea.1. Measure the RTL、RTT and RTH of rib-transverse process combinedarea.2. Measure the geometric morphology and cross-sectional geometry ofribs: take costal tubercle（0%）-CCJ （100%） as the standard length of the rib,and divide into4sections. Segmentation points are expressed withpercentages（respectively25%、50%、75%）, where in the tubercle of rib andcostal angle point for5%points. The ribs are divided into three zonesrespectively:（1zone）rib head-37.5%,（2zone）25%-75%, and（3zone）50%at-100%. Therefore, it can meet needs of designing different types of ribfixation plate. The general geometry includes different sections of ribcurvature （Rc） and ribs on the long axis of retroversion angles （Ra）. Ribs along its long axis in the coronal plane spread after the bending degree of theunrolled angle （Ua）（the value measurement and the rib12.5%-87.5%range）;3. To reduce the measurement errors, we divide the above4sections into8sections, measuring the quantitative indexes of rib section geometric shape,including the height（h）、inner surface height（lh）、width（w）、the corticalthickness of both sides（tin, tout） and medullary cavity area（Am）, to get the ribsection morphological changes. Then, determine the inner surface morphologyof ribs, including the costal groove position, to provide evidences for placinginternal fixation of the plate.4. To provide basic data for further study ofthoracoscopic optimal chest wall opening, measure the rib spacing of twoadjacent（rib spacing）.Results: Ribs display irregular arc, forming three-dimensional thoracicstructures. Costal groove starts from the lower head of rib, goes to the lateraltubercle of rib till the inner lower side, and disappears at the75%part,through which the intercostal nerve go. The length of rib-transverse processcombined area is20.79±1.62mm, thickness is16.04±1.45mm, inner surface ofthe rib height is8.80±1.55mm, the maximum values of general curved rubs onlong axis occur in the ribs of the first section（both rib head-37.5%section） inwhich the third rib is the longest(20.24±2.86m-1), the eighth rib in the secondsection is the shortest(6.14±0.96m-1), but its difference with seventh rib in thesecond section(6.17±1.21m-1) has no statistically significance（p＞0.05）. Thebending degree of the first, the second and the third section are17.69±2.17m-1,8.64±2.89m-1,8.25±1.69m-1. The rib curvature of7-9rib is the largest in thesecond section, and the rib curvature of3-6rib is the largest in the thirdsection（p＜0.05）. Each rib has a retroversion angle along its longitudinal axis,and its numerical value is30-50degrees. The rib unrolled angle decreasesgradually from the3-5rib while changes its direction from the6-10rib andincreases gradually. The cross-sectional area of marrow cavity taken along therib backbone interception, raging from the back27.59mm2to the front55.91mm2. Medial cortical thickness is1.06±0.24mm, lateral corticalthickness is1.22±0.38mm, the tubercle of rib,5%section outer cortical thickness was significantly higher than that in cortical thickness. Comparedwith other numbers of other interceptions, its difference has no statisticalsignificance（p＞0.05）. Rib height is12.52±1.94mm, inner surface height9.11±1.98mm, and width is7.40±1.63mm.Conclusions:1Multi-slice spiral CT three-dimensional reconstruction ofrib can accurately display the morphological characteristics, and measure itsgeometric features, which provide useful imaging measurement method forclinical utility so that the rib anatomy research becomes simple and accurate.2At the same time, the morphological parameters provide basis for designinginternal fixation plate of rib fracture and related instrument, which is expectedto promote the advancement of treatment modality, making the completion ofthoracoscopic rib fracture internal fixation possible. Furthermore, it laysfoundation for applying biodegradable osteosynthesis plate to thoracic fixationof rib fractures. |
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