Surgical treatment for the aberrant internal carotid artery in the middle ear with pulsatile tinnitus

Many previous reports have indicated that pulsatile tinnitus caused by an aberrant internal carotid artery (ICA) should not be treated surgically because of the risk of infection or aneurysm formation. We herein describe a case of aberrant ICA treated by middle ear surgery for which we introduced a novel approach. An 84-year-old man was presented with a one-year history of tinnitus in his right ear. Otoscopic examination demonstrated a whitish mass in the antero-inferior quadrant of the tympanic membrane associated with rhythmic pulsation. Images obtained by CT, MRI and MRA revealed protrusion of the ICA into the tympanic cavity, making contact with the tympanic membrane. Surgery to separate the tympanic membrane from the ICA was performed in order to relieve the pulsatile tinnitus. After the operation, the patient's aural activity was preserved and the tinnitus did not recur within a follow-up period of one year. In the present case, delicate middle ear surgery was effective for relief of the tinnitus. When treating patients with aberrant IAC showing features similar to the present case, the surgical approach we have described is worth attempting.     

机械加载对慢性脑缺血大鼠学习记忆障碍的改善作用

摘要：目的 探讨脉冲式机械加载对慢性脑缺血大鼠学习记忆能力的改善作用。方法 27只健康雄性SD大鼠 按随机数字表法分为假手术组（Sham组）、血管性痴呆模型组（VD组）和脊柱加载治疗组（VD+L组），每组9只。Sham 组仅分离双侧颈总动脉但不结扎；VD组分离双侧颈总动脉后永久性结扎建立VD模型；VD＋L组建立模型后每天接 受脊柱机械加载治疗，共5周。Morris水迷宫测试大鼠学习记忆能力；HE染色及尼氏染色观察大鼠大脑皮质及海马 组织的病理改变；免疫组织化学技术检测神经胶质纤维酸性蛋白（GFAP）的表达。结果 与VD组相比，VD+L组大 鼠逃避潜伏期明显缩短，穿越平台次数和停留平台象限时间显著增加，加载后明显改善神经元形态结构和存活状 态，海马锥体细胞明显增多，并抑制了海马及皮质中GFAP的表达。结论 机械加载可以明显改善慢性脑缺血后大 鼠的学习记忆障碍、保护缺血后神经元，该治疗作用可能与机械加载减轻海马和皮质神经元病理损伤、抑制胶质细 胞的活化有关。     

Elution kinetics,antimicrobial activity,and mechanical properties of 11 different antibiotic loaded acrylic bone cement

Antibiotic-loaded acrylic bone cements (ALABC) spacers are routinely used in the treatment of prosthetic joint infections. The objectives of our study were to evaluate different ALABC for elution kinetics, thermal stability, and mechanical properties. A 10 or 20% mixture (w/w) beads of medium viscosity bone cement (DePuy, Inc) and vancomycin (VAN), gentamycin (GM), daptomycin (DAP), moxifloxacin (MOX), rifampicin (RIF), cefotaxime (CTX), cefepime (FEP), amoxicillin clavulanate (AmC), ampicillin (AMP), meropenem (MER), and ertapenem (ERT) were formed and placed into wells filled with phosphate-buffered saline. Antibiotic concentrations were determined using high-performance liquid chromatography. Antimicrobial activity was tested against Micrococcus luteus ATCC 9341 or Escherichia coli ATCC 25922. AmC, AMP, and FEP concentration rapidly decreased after day 2, being almost undetectable at day 4. Sustained and high elution rates were observed with VAN, GM, MOX, and RIF for the 30-day duration of the experiment. DAP, MER, ERT, and CTX elution rates constantly decreased from day 4. All antibiotics tested retained antimicrobial activity proving thermal stability. Mechanical properties of ALABC were maintained except when RIF was used.     

Fatigue analysis of restored teeth longitudinally cracked under cyclic loading

ObjectiveTo investigate the fatigue behavior of restored teeth, in particular the mechanisms of longitudinal dentinal cracking under cyclic mechanical loading, using finite element analysis (FEA) and the stress-life (S-N) approach.MethodsTen root-filled premolars restored with resin composites were subjected to step-stress cyclic loading to produce longitudinal cracks. Fracture loads and number of cycles completed at each load level were recorded. FEA was used to predict the stress amplitude of each component under the global cyclic load. Both intact and debonded conditions were considered for the dentin-composite interface in the FEA. The predicted stress concentrations were compared with the fracture patterns to help elucidate the failure mechanisms. The S-N approach was further used to predict the lifetimes of the different components in the restored teeth. Cumulative fatigue damage was represented by the sum of the fractions of life spent under the different stress amplitudes.ResultsLongitudinal cracks were seen in ~50% of the samples with a mean fracture load of 770 ± 45 N and a mean number of cycles to failure of 32,297 ± 12,624. The longitudinal dentinal cracks seemed to start near the line angle of the cavity, and propagated longitudinally towards the root. The sum of fractions of life spent for the dentin-composite interface exceeded 1 after ~7000 cycles when that for dentin was much lower than 1, indicating that interfacial debonding would occur prior to dentin fracture. This was supported by micro-CT images showing widened interfacial space in the cracked samples. In the debonded tooth, FEA showed dentinal stress concentrations at the gingival wall of the cavity, which coincided with the longitudinal cracks found in the cyclic loading test. The sum of fractions of life spent for dentin was close to 1 at ~30,000 cycles, similar to the experimental value.SignificanceDebonding of the dentin-composite interface may occur prior to longitudinal cracking of dentin in root-filled teeth under cyclic loading. The approximate time of occurrence for these events could be estimated using fatigue analysis with stresses provided by FEA. This methodology can therefore be used to evaluate the longevity of restoration designs for root-filled teeth.     

Gastric and masticatory performances in full‐arch immediate loading rehabilitated patients

Full‐arch immediate loading implant rehabilitations provide patients with compromised dentition an effective treatment to improve their aesthetic and function. Aim of this prospective cohort study was to investigate the correlation between masticatory ability and gastric emptying rates among these patients. Ten subjects (five men and five women) with compromised dentition were tested in two occasions: before treatment and 30 days after the immediate loading rehabilitation. Masticatory ability was evaluated using the sieves test, and the gastric half emptying time (T_1/2) was assessed by means of the ¹³C‐octanoic acid breath test. A statistically significant increment (P < 0·005) in masticatory ability was found only in reference to the particles smaller than or equal to 4·75 mm, whereas the gastric emptying rate showed a statistically significant reduction between pre‐ and post‐treatment (P = 0·003). A moderate negative correlation (rho = 0·64, P = 0·048) between the percentage change in masticatory ability and the percentage change in gastric emptying rate was evidenced. Patients with compromised dentition rehabilitated with full‐arch immediate implant prostheses present a significant improvement of the gastric process.