Outcomes using an internal osteotomy and distraction device for corrective osteotomy of distal radius malunions requiring correction in multiple planes

PURPOSE: Many different methods have been proposed for correction of distal radius malunions; however, precise correction of a severe malunion that requires simultaneous adjustment of displacement, angulation, and rotation in multiple planes is difficult. This prospective study measured radiographic and functional outcomes using an adjustable osteotomy, distraction, and fixation system for distal radius malunions that required correction in multiple planes. METHODS: Five consecutive patients with symptomatic distal radius malunions requiring correction in multiple planes were recruited into this study. All patients had correction of the malunion with an adjustable osteotomy, distraction, and fixation device. Radiographic parameters and objective and subjective functional outcomes were measured before surgery and at 3 months, 6 months, and 1 year after surgery. RESULTS: All radiographic measurements improved after surgery. Grip strength, pinch strength, and the Jebsen-Taylor test showed only marginal improvement. Ulnar deviation of the wrist and forearm pronation-supination improved, but the wrist extension-flexion arc did not. The Michigan Hand Outcomes Questionnaire showed improvement in all domains, and significant improvement was seen in the overall, work, aesthetic, and satisfaction domains. The Michigan Hand Outcomes Questionnaire, however, also indicated a substantial amount of residual impairment in all domains, including activities of daily living and pain. CONCLUSIONS: Corrective osteotomy with the adjustable osteotomy, distraction, and fixation device resulted in improvement in distal radius anatomy and function. However, not all improvements were statistically significant, and anatomy and function did not returned to baseline levels. Despite residual disability, patients noted substantial improvement in subjective outcomes. This system is useful for improving anatomy and function in distal radius malunions that require correction in multiple planes, but patients should be informed that they cannot expect to regain normal anatomy or function. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.     

Effects of two anxiolytics on distraction,habituation and dishabitiuation

Rats were engaged in a baseline activity of licking and their distraction to tone stimuli measured by an interruption in licking. Habituation, distraction to a stimulus change and dishabituation (the return of distraction to the original tone) were studied. Ethanol (0.4 and 0.8 g/kg) and chlordiazepoxide (7.5 mg/kg) produced significantly faster habituation, a result that cannot be attributed to changes in the baseline response rate, or to differences in the initial distraction to the tone. All groups showed 24 hr retention to the tone when they were tested in the same state in which they were habituated. There was transfer of habituation between drugged and undrugged states for rats injected with chlordiazepoxide, but rats habituated undrugged showed no retention if tested after injections of ethanol. Chlordiazepoxide impaired the specificity with which the physical parameters were coded, whereas ethanol improved the specificity of coding. Neither drug affected dishabituation.     

牵张成骨区牙移动动物模型的建立

目的:建立双侧下颌骨牵张成骨区快速正畸牙移动的实验动物模型,为其后的系列研究建立可靠的实验平台。方法:选择8只牙列完整的Beagle犬,其中4只犬建立双侧下颌骨牵张成骨动物模型,牵张完成后即刻以150g力远中移动下颌第三前磨牙进入牵张成骨区;另外4只犬拔除双侧下颌第四前磨牙后3个月,以150g力远中移动下颌第三前磨牙。实验中,每周加力1次,拍摄X线片并记录牙移动速率。牙移动8周后,观察实验牙及其牙周组织特点。结果:接受牵张成骨手术的4只犬,双侧下颌骨均被成功延长1cm,前牙出现反合,无实验犬死亡。实验牙借助自制的持续加力装置移动进入牵张成骨区。实验组牙移动显著快于对照组,X线观察实验组牙移动进入牵张成骨区,牙根未见明显吸收。组织学观察压力侧牙槽骨和牙周膜未出现不可逆性损伤。结论:以Beagle犬为实验对象,用成品牵张成骨器借助种植支抗钉和自制的牙移动装置远中移动下颌第三前磨牙,可建立可靠的动物模型。     

Changes after surgically-assisted maxillary expansion (SARME) to the dentoalveolar, palatal and nasal structures by using tooth-borne distraction devices

Different devices are available to aid surgically-assisted maxillary expansion. In this study we have evaluated the changes to the anchoring teeth, the hard palate, and the lower nasal passage made by tooth-borne distraction devices. Thirty-one patients (mean (SD) age 28 (2) years) with deficiencies in the transverse width of the maxilla were examined by computed tomography and cone beam scans before and after operation. The data were analysed with the help of Wilcoxon's signed rank test and Spearman's r correlation. The mean (SD) distraction width was 6.5 (2.3) mm. All anchorage teeth were tilted (p < 0.01). The axes changed by a mean (SD) of 4.8 (0.9)° in the first premolar and 3.1 (0.8)° in the first molar. The nasal isthmus increased by a mean (SD) of 2.5 (0.3) mm. The hard palate adjacent to the anchoring teeth increased anteriorly by a mean (SD) of 2.8 (0.4) mm and posteriorly by 2.7 (0.4) mm. The hard palate was lowered by 1.2 (0.8) mm. There was a significant correlation in the distraction width, with changes in the intercoronal and interapical distances of the anchoring premolars (p < 0.05) and with the interapical distance of the anchoring molars (p < 0.01). There was also a correlation between the distraction width and the overall gain in width of the lower nasal passage (p < 0.05). The results suggested that surgically-assisted maxillary expansion with tooth-borne devices has significant effects on the anchoring teeth, the nasal floor, and the hard palate. Both tilting of the teeth and an evenly distributed movement of the segments were seen.     

听觉分散对手外伤患者换药疼痛的影响

目的 探讨听觉分散对手外伤患者换药疼痛的影响.方法 采用信封抽取随机分组方法,将120例准备换药的手外伤患者分为试验组和对照组,每组60例,试验组换药时戴耳机听音乐,对照组换药时只戴耳机不听音乐,两组患者均由同一名操作者使用相同的换药方法,在安静、一致的环境中完成换药及3次换药前后的疼痛评分,比较两组换药的疼痛程度.结果 试验组换药后的疼痛评分明显低于换药前及对照组,差异均有统计学意义(P＜0.01).结论 听觉分散可有效控制手外伤患者换药时的疼痛.     

Expression and Role of Interleukin-6 in Distraction Osteogenesis

Distraction osteogenesis is a special form of bone healing in which well-controlled distraction stresses and consequent tensile strains within callus tissue induce very efficient new bone formation. Proinflammatory cytokines are involved during the early phase of fracture healing and callus remodeling. Temporal expression patterns of proinflammatory cytokines were assessed in Sprague-Dawley rat tibial models of distraction osteogenesis and acute lengthening, and only interleukin-6 (IL-6) was found to be specifically induced during the distraction phase. IL-6 immunoreactivity was detected not only in hemopoietic cells and osteoblasts but also in the spindle-shaped cells of the fibrous interzone, where most of the tensile strains are concentrated. In vitro study revealed that IL-6 did not affect the proliferation of C3H10T1/2 cells, mouse bone marrow stromal cells (MSCs), or MC3T3-E1 cells; but its blocking antibody reduced the proliferation of C3H10T1/2 cells and MSCs. The mRNA expression of COL1A1 and osteopontin were not changed by IL-6 or its blocking antibody, but the alkaline phosphatase activities of MC3T3-E1 cells were increased by IL-6 and decreased by its blocking antibody. These findings indicate that IL-6 is a proinflammatory cytokine that responds to tensile strain during distraction osteogenesis. IL-6 negatively affects the proliferation of primitive mesenchymal cells, whereas the differentiation of more mature osteoblastic lineage cells is enhanced by IL-6 in vitro. IL-6 appears to be one of the cytokines involved in the complex network of signal cascades evoked during distraction osteogenesis and may differentially affect immature and mature osteoblastic lineage cells.     

Evaluation of recombinant human bone morphogenetic protein-2 in mandibular distraction osteogenesis in rabbits: Effect of dosage and number of doses on formation of bone

We evaluated the dose- and time-dependent response of recombinant human bone morphogenetic protein-2 (rhBMP-2) to the formation of bone in mandibular distraction osteogenesis. Twenty-one adult white New Zealand rabbits (3.0-3.8 kg) were used to establish the mandibular distraction model, 18 of which completed the experiment. Eight rabbits were given rhBMP-2 360 microg and eight 1080 microg; two were given no rhBMP-2. The fluids were injected into the regenerating bone at three different time sequences (days 5, 8, and 11 of active distraction; days 5 and 11 of active distraction; and day 11 of active distraction alone). After four weeks of consolidation, the specimens were harvested and examined radiographically by micro-computed tomography (micro-CT), and histologically. The formation and remodelling of bone in distraction osteogenesis was significantly increased by the addition of rhBMP-2, and the increase was dose-dependent. There was no significant difference between different dosage regimens. A single injection of rhBMP-2 at the end of the distraction phase was as effective as multiple injections.     

Two separate mechanisms underlie auditory change detection and involuntary control of attention

We used behavioral and event-related potential (ERP) measures to study the neural mechanisms of involuntary attention switching to changes in unattended sounds. Our subjects discriminated two equiprobable sounds differing in frequency (fundamental frequency 186 or 196 Hz) while task-irrelevant intensity decrements or increments (-3, -6, -9, +3, +6, or +9 dB, standard intensity 60 dB HL) infrequently occurred in the same sounds. In line with the results of previous studies, discrimination performance deteriorated with increasing magnitude of the task-irrelevant intensity change. However, these distraction effects were dissimilar for intensity increments and decrements: while there were no differences in reaction time (RT) between intensity decrements and increments, hit rates (HR) were lower for large intensity increments than for large decrements. ERPs to task-irrelevant intensity increments and decrements were also distinctly different: the response to intensity increments consisted of an N1 enhancement, mismatch negativity (MMN), and P3a, while the response to intensity decrements consisted only of MMN. These results are consistent with the assumption that two separate mechanisms (indexed by N1 and MMN) underlie auditory change detection. However, the finding that distinct distraction effects were obtained for both intensity decrements and increments but that the P3a is elicited only by the intensity increments seems to suggest that P3a may not be regarded as a general index of attentional shift but rather it is only generated in conditions in which an enhanced N1 is elicited, too.     

The effect of age on involuntary capture of attention by irrelevant sounds: a test of the frontal hypothesis of aging

The aim of this study was to examine the effects of aging on the involuntary capture of attention by irrelevant sounds (distraction) and the use of these sounds as warning cues (alertness) in an oddball paradigm. We compared the performance of older and younger participants on a well-characterized auditory-visual distraction task. Based on the dissociations observed in aging between attentional processes sustained by the anterior and posterior attentional networks, our prediction was that distraction by irrelevant novel sounds would be stronger in older adults than in young adults while both groups would be equally able to use sound as an alert to prepare for upcoming stimuli. The results confirmed both predictions: there was a larger distraction effect in the older participants, but the alert effect was equivalent in both groups. These results give support to the frontal hypothesis of aging [Raz, N. (2000). Aging of the brain and its impact on cognitive performance: integration of structural and functional finding. In F.I.M. Craik & T.A. Salthouse (Eds.) Handbook of aging and cognition (pp. 1-90). Mahwah, NJ: Erlbaum; West, R. (1996). An application of prefrontal cortex function theory to cognitive aging. Psychological Bulletin, 120, 272-292].