MRI characteristics of MOG-Ab associated disease in adults: An update

Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS.     

The safety and feasibility of minimal invasive plate osteosynthesis (MIPO) of the posterior aspect of the humerus: A cadaveric study

The aim of this study was to determine the feasibility of applying MIPO of the humerus via the posterior approach and to observe the tension of the radial nerve in different elbow positions. Two separate incisions were made on the posterior aspect of the humerus in ten fresh cadavers (20 humeri). The radial nerve was identified at the proximal incision and the distances through which the nerve could be elevated from the bone with the elbow in flexion and extension were measured. A 10‐hole extra‐articular distal humeral locking compression plate was inserted and fixed through the submuscular tunnel. The tunnel was then explored to identify any entrapment of the radial nerve and to observe the anatomical relationship of the radial nerve to the plate and bone. There was no entrapment of the radial nerve or its branches. The distances through which the radial nerve could be elevated were greater with the elbow in extension than in flexion (P < 0.01). The radial nerve crossed the medial and lateral borders of the posterior surface of the humerus at 80.1–132 mm (average 104.7 mm) and 116.6–175.5 mm (average 142.7 mm) of its total length, respectively. The axillary nerve was located at 38.7–61.7 mm (average 47.9 mm) of total humeral length. MIPO of the humerus using the posterior approach is an alternative option for treating distal humeral shaft fracture. The risk of radial nerve injury can be minimized by careful dissection in the proximal incision. Clin. Anat. 32:176–182, 2019. © 2018 Wiley Periodicals, Inc.     

Identifying the emergence of the superficial peroneal nerve through deep fascia on ultrasound and by dissection: Implications for regional anesthesia in foot and ankle surgery

Regional anesthesia relies on a sound understanding of anatomy and the utility of ultrasound in identifying relevant structures. We assessed the ability to identify the point at which the superficial peroneal nerve (SPN) emerges through the deep fascia by ultrasound on 26 volunteers (mean age 27.85 years ± 13.186; equal male: female). This point was identified, characterized in relation to surrounding bony landmarks (lateral malleolus and head of the fibula), and compared to data from 16 formalin‐fixed human cadavers (mean age 82.88 years ± 6.964; equal male: female). The SPN was identified bilaterally in all subjects. On ultrasound it was found to pierce the deep fascia of the leg at a point 0.31 (±0.066) of the way along a straight line from the lateral malleolus to the head of the fibula (LM‐HF line). This occurred on or anterior to the line in all cases. Dissection of cadavers found this point to be 0.30 (±0.062) along the LM‐HF line, with no statistically significant difference between the two groups (U = 764.000; exact two‐tailed P = 0.534). It was always on or anterior to the LM‐HF line, anterior by 0.74 cm (±0.624) on ultrasound and by 1.51 cm (±0.509) during dissection. This point was significantly further anterior to the LM‐HF line in cadavers (U = 257.700, exact two‐tailed P < 0.001). Dissection revealed the nerve to divide prior to emergence in 46.88% (n = 15) limbs, which was not identified on ultrasound (although not specifically assessed). Such information can guide clinicians when patient factors (e.g., obesity and peripheral edema) make ultrasound‐guided nerve localization more technically challenging. Clin. Anat. 32:390–395, 2019. © 2019 Wiley Periodicals, Inc.     

角膜电刺激对糖尿病大鼠前部缺血性视神经病变模型的影响

观察并评估角膜电刺激对糖尿病大鼠前部缺血性视神经病变（AION）模型的影响。方法：实验 研究。健康雄性Sparague-Dawley大鼠40只，随机分组后抽出8只作为正常大鼠组。余下32只先予 以链脲佐菌素腹腔注射建立糖尿病大鼠模型，将造模成功的大鼠随机抽出8只作为糖尿病组，余下 24只糖尿病大鼠采用孟加拉玫瑰红联合532 nm激光方法建立AION大鼠模型。将24只造模成功的 AION大鼠随机分成3组，每组8只，分别为AION模型组，不予任何处理；电刺激组，予以角膜电刺 激（刺激参数为：电流1 mA，频率20 Hz，波宽1 ms/phase，刺激时间1 h，隔日1次，刺激2周）；假电 刺激组，电极安放位置与电刺激组相同，仅不接通电源。2周后5组大鼠进行眼底照相、光学相干断 层扫描和视觉诱发电位，然后处死，行视网膜及视神经冰冻切片，苏木精伊红染色观察。数据采用 单因素方差分析和LSD-t检验进行分析。结果：正常大鼠组视盘上半部视网膜厚度为（211±13）μm， 糖尿病大鼠组为（206±16）μm，AION模型组为（240±54）μm，假电刺激组为（216±11）μm，电刺 激组为（198±4）μm，5组视盘上半部视网膜厚度差异有统计学意义（F=2.854，P=0.038）。其中AION 模型组视盘上半部视网膜厚度高于正常组、糖尿病组、电刺激组，差异均有统计学意义（P<0.05）； 正常组与糖尿病组差异无统计学意义，AION模型组与假电刺激组未见明显差异。视觉诱发电位示 AION模型组N1潜伏期较电刺激组延长，差异有统计学意义（t=4.1，P<0.001）；AION模型组P1潜伏 期较正常组、糖尿病组、假电刺激组、电刺激组延长，差异均有统计学意义（t=4.1、2.5、2.6、3.2， P<0.05）；电刺激组N1-P1波幅大于假电刺激组，差异有统计学意义（t=4.0，P<0.001）。结论：角膜电 刺激能促进糖尿病大鼠前部缺血性视神经病变模型肿胀的视盘变薄，加速视盘水肿的消退，同时在 一定程度上改善视功能。     

Structures at Risk From an Intermetatarsal Screw for Lapidus Bunionectomy: A Cadaveric Study

The Lapidus bunionectomy is performed to treat hallux valgus. Recurrence of the deformity remains a concern. A transverse intermetatarsal screw spanning the base of the first metatarsal to the base of the second can increase stability. The neurovascular bundle is located within the proximity of this screw. In this study, we assessed the structures at risks with the use of this technique. In 10 specimens, a guide wire was placed, and a 4.0-mm cannulated screw was inserted. The neurovascular bundle was dissected and inspected for direct trauma to the neurovascular bundle, and the proximity of the screw was measured using a digital caliper. Ten cadaveric specimens were used. The dorsalis pedis artery and deep peroneal nerve were free from injury in 9 of 10 specimens. In those 9 specimens, the neurovascular bundle was located dorsal in relation to the screw. The mean distance of the screw to the neurovascular bundle was 7.1 ± 3.3 mm. The mean distance from the screw to the first tarsometatarsal joint (TMTJ) was 14.7 ± 4.3 mm. The mean distance from the screw as it entered the second metatarsal to the second TMTJ was 18.0 ± 7.2 mm. In 1 specimen, the screw was found to be traversing through the neurovascular bundle. The distance from the screw to the first TMTJ was 15.0 mm. The distance of the screw from where it entered the second metatarsal to the second TMTJ was 24.0 mm. Although the intermetatarsal screw avoided the neurovascular cases in most instances, there is some anatomic risk to the neurovascular bundle. Further study is warranted to evaluate clinical results using the intermetatarsal screw for the modified Lapidus procedure.     

甲状腺激素对小鼠面神经损伤轴突再生及神经电生理功能的影响

目的： 探讨甲状腺激素对小鼠面神经损伤轴突再生及神经电生理功能的影响。方法： 将64只小鼠随机分为4组,即假手术组、模型组、甲状腺素组、甲状腺素+LY组,每组16只。除假手术组外,其余组均建立面神经损伤模型。术后苏醒开始干预,甲状腺素组于损伤处皮下注射50 μg/kg中性甲状腺素溶液,甲状腺素+LY组在甲状腺素组基础上腹腔注射600 μg/kg PI3K/AKT通路抑制剂LY294002,假手术组和模型组于损伤处注射生理盐水,每天1次,持续2周。干预结束后进行神经电生理检测,锇酸染色进行再生轴突计数,Western免疫印迹法检测面神经组织中p-AKT、NGF、BDNF蛋白的表达。采用SPSS 21.0软件包对数据进行统计学分析。结果： 假手术组正常神经髓鞘外未见新生轴突。与模型组相比,甲状腺素组和甲状腺素+LY组再生轴突数均升高,甲状腺素组显著高于甲状腺素+LY组（P<0.05）。与假手术组相比,模型组运动神经传导速度（MNCV）和波幅降低,潜伏期延长（P<0.05）;与模型组相比,甲状腺素组和甲状腺素+LY组MNCV、波幅升高,甲状腺素组显著高于甲状腺素+LY组（P<0.05）;与模型组相比,甲状腺素组和甲状腺素+LY组潜伏期缩短,甲状腺素组显著短于甲状腺素+LY组（P<0.05）。与假手术组相比,模型组p-AKT、NGF、BDNF蛋白相对表达量显著升高（P<0.05）;与模型组相比,甲状腺素组p-AKT蛋白相对表达量显著升高,甲状腺素+LY组显著降低（P<0.05）;与模型组相比,甲状腺素组和甲状腺素+LY组NGF、BDNF蛋白相对表达量升高,甲状腺素组显著高于甲状腺素+LY组（P<0.05）。结论： 甲状腺激素可有效促进小鼠面神经损伤轴突再生,改善神经电生理功能,其机制可能是通过促进AKT磷酸化而发挥调控作用。     

Bands of Fontana are caused exclusively by the sinusoidal path of axons in peripheral nerves and predict axon path; evidence from rodent nerves and physical models

The precise cause of the bands of Fontana, striations on peripheral nerves visible to the naked eye, has been the subject of debate for hundreds of years. Some researchers have described them as reflecting the sinuous course of nerve fibres passing through nerves, and others have proposed that endoneurial collagen and sheaths surrounding nerves play a role in their appearance. We hypothesised that the bands are caused exclusively by reflection of light from the surfaces of nerve fibres travelling in phase in sinusoidal waveforms through peripheral nerves. We aligned images of obliquely illuminated nerves with confocal images of axons in those nerves, and the numbers and positions of the bands precisely matched the axonal waves. We also developed three‐dimensional models of nerves with representations of the sinusoidal path of axons at their surface. We observed patterns resembling the bands of Fontana when these models were obliquely illuminated. This provides evidence that the bands of Fontana can be caused by light reflected sinusoidal path of axons alone. We subsequently describe a mechanism of band production based on our observations of both nerves and models. We report that smaller diameter nerves such as phrenic nerves and distal branches of sciatic nerves have shorter band intervals than larger nerves, such as proximal trunks of sciatic nerves, and that shorter band intervals correlate with longer axons per unit length of nerve, which suggests a greater tolerance to stretch. Inspection of banding patterns on peripheral nerves may permit prediction of axon length within nerves, and assist in the interpretation of nerve conduction data, especially in diseases where axon path has become altered.