Rapid Increase in Neural Conduction Time in the Adult Human Auditory Brainstem Following Sudden Unilateral Deafness

Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.     

Dorsal suspension for Morton’s neuroma: A comparison with neurectomy

BackgroundThe purpose of this study was to investigate and compare the clinical outcomes of dorsal suspension with those of neurectomy for the treatment of Morton’s neuroma.MethodsWe conducted a retrospective study of dorsal suspension and neurectomy group. The dorsal suspension was performed by dorsal transposition of neuroma over the dorsal transverse ligament after neurolysis. The visual analog scale (VAS), the Foot and Ankle Ability Measure (FAAM), postoperative satisfaction, and complications were evaluated.ResultsBoth groups reported significant pain relief, and there were no significant differences between the groups with respect to postoperative pain. The postoperative FAAM outcomes showed no significant between-group differences. Satisfaction analysis showed ‘excellent’ and ‘good’ results in the dorsal suspension and neurectomy groups (95% and 77.7%, respectively). Complications of numbness and paresthesia reported in the dorsal suspension group (5% and 5%, respectively) were significantly fewer than those of neurectomy group (61.1% and 33.3%, respectively) (both, p < .05).ConclusionsWith its favorable results, dorsal suspension can be another operative option for the treatment of Morton’s neuroma.Level of Evidence: Level III, retrospective comparative case series.     

听神经瘤术中耳蜗电图监测与听力保护

目的：评价耳蜗神经电位活动直接监护在听神经瘤手术中对保护听力的作用。方法：听神经瘤手术中施行耳蜗电图监护。结果：１６例听神经瘤手术中施行耳蜗电图监护者，术后听力保留５例（３１％），其中４例为有效听力保留。肿瘤在２厘米以下者听力保留为３８％（５／１３）。结论：听神经瘤手术过程中采用耳蜗电图监护，能敏感地反应即时的听神经功能状况，给术者及时的反馈信息，有助于听力保护     

近端/远端复合肌肉动作电位振幅比率在术后面神经功能评估上的价值

目的 探讨近端/远端复合肌肉动作电位振幅比率在术后面神经肿瘤侵犯段功能评估上的价值和对早期面神经修复的指导意义。方法 比较术末面神经近端/远端复合肌肉动作电位振幅比率和术后2周、6个月患侧面神经功能的H-B分级之间的关系。结果 术后6个月面神经H-B分级恢复到Ⅰ-Ⅱ级者,术末近端/远端复合肌肉动作电位振幅比率均>0.3。结论 术末面神经近端/远端复合肌肉动作电位振幅比率是判断术后面神经远期功能,特别是肿瘤侵犯段功能的重要指标,为术中直接修复面神经提供了指导依据。     

两种MRI序列对听神经瘤成象的比较与评价

为选择中等场强的ＭＲＩ听神经瘤成像最佳序列。收集手术和病理证实的听神经瘤１３５例，分析序列Ⅰ、Ⅱ对内听道中心层面、三叉神经显示率及ＭＲ征象的显示情况。结果：序列Ｉ择内听道中心层面及三叉神经的显示均优于序列Ⅱ，序列Ⅱ在显示肿瘤内囊变、出血、不肿优于序列Ｉ；对肿瘤钙化、肿瘤血管、脑干移位的观察，两者相仿。结果显示：序列Ｉ在中等场经下作为听神经瘤成像的首选序列，并中运用到小脑角区ＭＲＩ成像。     

听神经瘤的MRI诊断(20例报告)

回顾分析了20例22个听神经瘤的MRI表现。MRI检查采用0.35T超导MT/S成像系统,常规行冠状面T_1加权及横断面T_(1-)T_2加权成像。据瘤体大小将病灶分成4组,包括限于内听道者1例,1-2cm者2例,2.1-3cm者8例,大于3cm者11例,结果表明,T_1加权像对听神经瘤的诊断价值较大,主要依据是CP角内出现与听神经根部相连的肿块或听神经明显增粗;大于2cm的听神经瘤多可发生囊变、出血及脑干、Ⅳ脑室受压。除可发现位于内听道内的微小肿瘤外,MRI在肿瘤囊变、出血、周围结构受压情况、肿瘤供血血管及肿瘤与周围粘连情况的显示上均具有一定的优越性。     

HISTOLOGICAL COMPARISON OF THE THIRD INTERDIGITAL NERVE IN PATIENTS WITH MORTON'S METATARSALGIA AND CONTROL PATIENTS

This study compares the histology of the plantar-digital nerve supplying the third web space in asymptomatic patients with those who have clinically diagnosed Morton's metatarsalgia. Despite several studies concentrating on the histological changes in the interdigital nerve, the relevance of these changes is a matter of contention while the exact pathological process responsible for the symptoms has not been determined. The histological findings in control patients were identical to Morton's patients with the exception of demyelination, which was more common in the Morton's group. This suggests that the characteristic nodule and fibrotic changes seen in the interdigital nerves of patients with Morton's neuroma cannot account for the symptoms and that the changes seen in the neurovascular bundle are degenerative in origin and are found in asymptomatic patients.     

伽玛刀治疗听神经瘤(附98例分析)

目的 评价伽玛刀治疗听神经的效果。方法 应用OUR旋转式伽玛刀治疗听神经98例。肿瘤直径512～29．7min．平均18.8mm。采用多个放射中心联合照射，周边等剂量曲线为45％-70％，边缘剂量10-13Gy。结果 81例获14。84个月随访，平均39个月。MRI示41例（50．6％）肿瘤缩小，38例（46.9％）无变化，2例（2．5％）增大；25例（30.9％）肿瘤中心失增强。无面瘫和面部麻木，听力保留率59.2％。结论 伽玛刀对听神经瘤有较高的肿瘤控制率，并能保留有用听力，对面神经、三又神经损伤小，是小至中等大小听神经瘤可供选择的治疗方法，及术后残余和复发肿瘤的重要辅助治疗手段。