Extreme/direct lateral interbody fusion (X/DLIF) has been used to treat various lumbar diseases. However, it involves risks to injure the lumbar plexus and abdominal large vessels when it gains access to the lumbar spine via lateral approach that passes through the retroperitoneal fat and psoas major muscle. This study was aimed to determine the distribution of psoas major and abdominal large vessels at lumbar intervertebral spaces in order to select an appropriate X/DLIF approach to avoid nerve and large vessels injury. Magnetic resonance imaging scanning on lumbar intervertebral spaces was performed in 48 patients (24 males, 24 females, 54.2 years on average). According to Moro's method, lumbar intervertebral space was divided into six zones A, I, II, III, IV and P. Thickness of psoas major was measured and distribution of abdominal large vessels was surveyed at each zone. The results show vena cava migrate from the right of zone A to the right of zone I at L1/2-L4/5; abdominal aorta was located mostly to the left of zone A at L1/2-L3/4 and divided into bilateral iliac arteries at L4/5; Psoas major was tenuous and dorsal at L1/2 and L2/3, large and ventral at L3/4 and L4/5. Combined with the distribution of nerve roots reported by Moro, X/DLIF approach is safe via zones II-III at L1/2 and L2/3, and via zone II at L3/4. At L4/5, it is safe via zones I-II in left and via zone II in right side, respectively.

BackgroundMore and more older patients receive the surgery after hip fracture. However, the mortality rate is high. Prognostic nutritional index (PNI) is associated with prognosis in hip fracture patients. In the current study, we proposed a novel prognostic score, named c-reactive protein/PNI ratio (CRP/PNI ratio), for predicting the prognosis for geriatric orthopedic population.MethodsThis is a prospective study. Eighty cases of hip fracture surgery in the elderly population were studied to reveal the relationship between the CRP/PNI ratio and the clinicopathological characteristics of the elderly patients. Clinical data included age, sex, weight, length of stay, duration of surgery, comorbidity, and biological data were collected. The primary endpoint was the 1-year mortality rate.ResultsCox regression and log-rank tests were used to evaluate the correlation of CRP/PNI to the one-year mortality. The one-year mortality rate was low in the patients with a low CRP/PNI ratio (P < 0.001). Univariate and multivariate survival analyses proved that CRP/PNI was an important factor to predict the one-year mortality rate of the geriatric hip fracture surgery patients.ConclusionLow CRP/PNI ratio was significantly associated with low one-year mortality rate in older patients after hip fracture surgery.

The distal tibiofibular syndesmosis is an important structure for ankle stability. The objective of this study was to evaluate the motion of the syndesmosis under different loading patterns and determine the characteristics of the syndesmotic motion. Methods: Six fresh cadaveric lower extremity specimens with the knee reserved were tested in this study. The skin and muscles were removed with all ligaments around the syndesmosis and knee and ankle joint intact. An axial load of 600 N was applied to the specimens with the ankle joint in 10 dorsiflexion, neutral position, and 15 plantar flexion using a universal material testing machine. Then, with the ankle joint positioned neutrally, a combination of 600-N axial and 5-Nm torsional external rotation loading was applied to the specimens. The medial-lateral and anterior-posterior displacement and rotation of the distal fibula relative to the distal tibia were measured. Results: Under the axial loading, the distal fibula tended to move medially and anteriorly and rotate internally with the ankle positioned from the neutral position to 15 plantar flexion. Meanwhile, when the ankle was positioned from the neutral position to 10 dorsiflexion, the distal fibula tended to move laterally and posteriorly and rotate externally. Under the combined loading, with respect to the isolated axial loading, the distal fibula tended to move medially and posteriorly, and rotate externally relative to the distal tibia. Conclusion: Micro motion existed in the syndesmosis. The relative motion of the syndesmosis was correlated to the ankle position and loading patterns.

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