Shabshin Nogah, Ougortsin Vlad, Zoizner Gil, Gefen Amit
Department of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer 52621, affiliated to Sackler Faculty of Medicine-Tel Aviv University, Ramat Aviv, Tel Aviv, Israel.
Clin Biomech (Bristol). 2010 Jun;25(5):402-8. doi: 10.1016/j.clinbiomech.2010.01.019. Epub 2010 Feb 25.
Deep tissue injury is the new acceptable term for deep pressure ulcers. Deep tissue injury of the buttocks is typically caused by sustained soft tissue deformations under the ischial tuberosities. Wheelchair users are at high risk, and although usually laterally tilted, the effect of tilts on tissue deformations is unknown. This has brought us to investigate buttocks tissue compressive deformations between the ischial tuberosities and skin during sitting in various body tilts, utilizing weight-bearing Magnetic resonance imaging (MRI).
Ten healthy volunteers underwent sitting MRI, in six postures including neutral with/without weight-bearing, 10 degrees and 20 degrees lateral-tilts, and 20 degrees and 40 degrees anterior tilts. Studies utilized a coronal T1-weighted sequence. Images were evaluated for thickness of tissues between the skin and the lowest point of the ischial tuberosity, of fat between the skin and the gluteus muscle and of muscle between the ischial tuberosity and fat. Measurements in weight-bearing positions were compared to the non-weight-bearing for calculation of compressive tissue deformations in each trunk tilt. Statistical analysis was obtained utilizing multiple pairwise t-tests with Bonferroni corrections.
Muscle and soft tissue compressive deformations, from highest to lowest, were 20 degrees -lateral-tilt (87%, 72%), lateral-10 degrees (85%, 70%), anterior-20 degrees (79%, 67%), anterior-40 degrees (74%, 64%), and neutral (72%, 59%). For the fat, highest was anterior-tilts (42%), followed by lateral-20 degrees -tilt (41%), lateral-10 degrees (39%) and neutral (35%).
For lateral tilts, the higher the angle was, the higher the compressive deformation was. However, the most profound change in compressive deformation occurred at the small angle tilts.
深部组织损伤是深部压疮的新认可术语。臀部深部组织损伤通常由坐骨结节下持续的软组织变形引起。轮椅使用者风险较高，尽管通常向一侧倾斜，但倾斜对组织变形的影响尚不清楚。这促使我们利用负重磁共振成像（MRI）研究不同身体倾斜姿势下坐姿时坐骨结节与皮肤之间臀部组织的压缩变形情况。
10名健康志愿者接受坐姿MRI检查，姿势包括负重和不负重的中立位、10度和20度侧倾、20度和40度前倾。研究采用冠状面T1加权序列。评估皮肤与坐骨结节最低点之间组织的厚度、皮肤与臀肌之间脂肪的厚度以及坐骨结节与脂肪之间肌肉的厚度。将负重位的测量值与非负重位进行比较，以计算每个躯干倾斜角度下的组织压缩变形。采用带有Bonferroni校正的多重成对t检验进行统计分析。
肌肉和软组织的压缩变形从高到低依次为：20度侧倾（87%，72%）、10度侧倾（85%，70%）、20度前倾（79%，67%）、40度前倾（74%，64%）和中立位（72%，59%）。对于脂肪，最高的是前倾（42%），其次是20度侧倾（41%）、10度侧倾（39%）和中立位（35%）。
对于侧倾，角度越高，压缩变形越高。然而，压缩变形最显著的变化发生在小角度倾斜时。
