改良V-Y外眦开大成形术的临床应用

目的：探讨改良V-Y外眦开大成形新术式。方法：将Y形切口线设计在睑缘灰线，板层劈开上下睑，并在切口末端增加两条垂直于睑缘的辅助切口线，切开睑板及睑结膜；部分或完全切断外眦韧带，充分分离使外眦呈“游离状态”。在无张或微张力的情况下外移外眦。结果：102例外眦开大成形术99例达到预期效果，开大外眦达1．5～5mm。结论：改良V-Y外眦开大成形术相比传统手术，保留了外眦外形结构，术后外眦无变形，远期回缩轻微，是目前比较理想的合乎美学原理的外眦开大成形术式。     

Predictive value of retinal function by the Purkinje test in patients scheduled for cataract surgery in Kinshasa, DR Congo

AIM: To assess the retinal function in patients with dense cataracts in resource poor settings in Kinshasa, DR Congo. METHODS: In a tertiary eye care center, the Purkinje entoptic test was performed as part of the ophthalmological examination in 98 eyes in patients with cataract, using a penlight. Totally 92 cataract patients including 86 patients suffered from unilateral and 6 from bilateral cataracts were included in the study. The investigator asked the patients about their perception of the vascular pattern most commonly described as a leafless or dead tree. Visual acuity≥6/60 was considered an indication of good visual function and visual acuity<6/60 of poor function. Following small incision cataract surgery, best corrected visual acuity (BCVA) was determined and compared with the preoperative findings. RESULTS: Out of 98 eyes, there were 80 (81.6%) where the Purkinje entoptic phenomenon was reported by the patients. After cataract surgery, out of the 80 eyes, there were 75 (93.8%) with a BCVA of better than 6/60, whereas in 5 eyes (6.2%), BCVA was 6/60 or less. Out of the 18 eyes (18.4%) where no Purkinje tree was recognized, there were 14 (77.8%) with BCVA of better than 6/60, whereas in 4 (22.2%) BCVA was 6/60 or less. CONCLUSION: The Purkinje entoptic test is successfully used for preoperative assessment of retinal function in patients with dense cataract. However, further investigation and refinement of the test is necessary to validate the method for use in sub-Saharan conditions.     

Microsurgical anatomy of the abducens nerve

The aim of this study is to demonstrate and review the detailed microsurgical anatomy of the abducens nerve and surrounding structures along its entire course and to provide its topographic measurements. Ten cadaveric heads were examined using ×3 to ×40 magnification after the arteries and veins were injected with colored silicone. Both sides of each cadaveric head were dissected using different skull base approaches to demonstrate the entire course of the abducens nerve from the pontomedullary sulcus to the lateral rectus muscle. The anatomy of the petroclival area and the cavernous sinus through which the abducens nerve passes are complex due to the high density of critically important neural and vascular structures. The abducens nerve has angulations and fixation points along its course that put the nerve at risk in many clinical situations. From a surgical viewpoint, the petrous tubercle of the petrous apex is an intraoperative landmark to avoid damage to the abducens nerve. The abducens nerve is quite different from the other nerves. No other cranial nerve has a long intradural path with angulations and fixations such as the abducens nerve in petroclival venous confluence. A precise knowledge of the relationship between the abducens nerve and surrounding structures has allowed neurosurgeon to approach the clivus, petroclival area, cavernous sinus, and superior orbital fissure without surgical complications. Clin. Anat. 25:1030–1042, 2012. © 2012 Wiley Periodicals, Inc.     

Full colour reproduction of figures originally submitted in colour

Case reports on three patients who underwent vitrectomy assisted t-PA injection for the management of branch retinal vein occlusion. Three-port, 20-gauge vitrectomy was performed under local anesthesia. After posterior vitreous detachment and fluid-air exchange, 50 μ g t-PA/0.5 ml were injected in the eye. All patients were instructed for strict supine position for 6 hours. Main outcome measure was visual acuity. Three patients with branch vein occlusion (BVO) were studied, with duration of symptoms less than 25 days, and mean follow-up period of 18.8 months. Although no intraoperative complications were noticed, no one showed any significant improvement of vision. One patient required a second operation for the management of intravitreal hemorrhage, and another developed an epiretinal membrane. Vitrectomy assisted t-PA injection does not seem to improve the course of branch retinal vein occlusion in this small case series. Future research on intravitreal thrombolysis needs to be focused on additional mechanical approaches and modalities that can facilitate the access of the drug into the vascular lumen.     

Preliminary Risk assessment for Acrylamide and Peripheral Neuropathy

Acrylamide (ACM) is a high-volume industrial chemical with diverse uses in manufacturing, construction and laboratory research. ACM is a well-established neurotoxic agent causing peripheral neuropathy with impairment in the arms and legs of exposed workers, most thoroughly studied in Swedish tunnel workers exposed to ACM grouting. A quantitative risk assessment was performed to assess ACM risk to workers. Using data from a published paper investigating peripheral neuropathies in Chinese chemical workers, estimates of exposure response for vibration perception threshold and nerve conduction velocities were calculated, based on hemoglobin adducts and air concentrations as exposure metrics. The benchmark dose procedure was applied in order to calculate excess risks of impairment, defined as adverse performance exceeding the 95^th percentile in unexposed populations, at various concentrations of airborne ACM exposure. Under the assumptions in this risk assessment, after three years of inhalation exposure at 0.3 mg/m³, the excess attributable impairment manifest in vibration perception and nerve conduction velocity is estimated to occur in 1-2% of workers. For 10 years at 0.3 mg/m³ ACM inhalation (equivalent to 3 years at 1.0 mg/m³) the excess prevalence of impairment would be 2-14% of workers, assuming the effect continues to accrue linearly in time. Using published data, the risks of impairment from peripheral neuropathy attributable to exclusively airborne ACM exposure can be predicted for exposure periods less than 10 years. The risks associated with dermal and airborne ACM exposures can be estimated by characterizing working process environments using ACM Hb-adduct levels and possibly monitored with urinary biomarkers.     

Intraoperative lateral rectus electromyographic recordings optimized by deep intraorbital needle electrodes

ObjectiveWe demonstrate the advantages and safety of long, intraorbitally-placed needle electrodes, compared to standard-length subdermal electrodes, when recording lateral rectus electromyography (EMG) during intracranial surgeries.MethodsInsulated 25 mm and uninsulated 13 mm needle electrodes, aimed at the lateral rectus muscle, were placed in parallel during 10 intracranial surgeries, examining spontaneous and stimulation-induced EMG activities. Postoperative complications in these patients were reviewed, alongside additional patients who underwent long electrode placement in the lateral rectus.ResultsIn 40 stimulation-induced recordings from 10 patients, the 25 mm electrodes recorded 6- to 26-fold greater amplitude EMG waveforms than the 13 mm electrodes. The 13 mm electrodes detected greater unwanted volume conduction upon facial nerve stimulation, typically exceeding the amplitude of abducens nerve stimulation. Except for one case with lateral canthus ecchymosis, no clinical or radiographic complications occurred in 36 patients (41 lateral rectus muscles) following needle placement.ConclusionsIntramuscular recordings from long electrode in the lateral rectus offers more reliable EMG monitoring than 13 mm needles, with excellent discrimination between abducens and facial nerve stimulations, and without significant complications from needle placement.SignificanceLong intramuscular electrode within the orbit for lateral rectus EMG recording is practical and reliable for abducens nerve monitoring.     

腹外斜肌的神经入肌点定位与肌内神经分布研究

目的　对人腹外斜肌的神经入肌点定位和肌内神经染色观察，为其临床应用提供形态学资料。 方法　成尸11具定位神经入肌点和5具行Sihler’s 肌内神经染色。 结果　腹外斜肌受下8对肋间神经外侧肌支支配，各个肌齿的神经入肌点距离相应肌齿起端中点(1.54±0.33)cm，位于锁骨中线与第5肋下缘的交界处至腋后线与第11肋下缘交界处的连线上。Sihler’s染色显示支配腹外斜肌的肋间神经外侧肌支入肌后分出小分支分布到各肌齿的起端1/3，然后约在各肌齿的近、中1/3交界处分出2支二级神经分支，即上支与下支，它们分出小分支分布到各肌齿的中间1/3，相邻两个肌齿的上支与下支在各肌齿中远部形成“U”形吻合，从“U”形吻合弓上分出小分支分布到各肌齿的止端1/3。在腹外斜肌上半部，各肌齿的神经分支分布到相应的肌齿，但在腹外斜肌下半部，上一肌齿的远侧下份是由下一肌齿的神经分支(上支)分布。 结论　①为临床上腹壁局部麻醉和术后切口疼痛的神经阻滞提供指导意义；②腹外斜肌中远部从上至下形成“波浪形”的神经分支密集区；③腹部手术切口建议不要超过四个肌齿。     

双台阶水平井钻井实时跟踪系统应用研究——以哈得油田HD10-HX井为例

哈得油田石炭系中泥岩段薄砂层油藏埋藏深、油层薄,且受岩性控制层状边水未饱和,采用以地质导向为基础的双台阶水平井钻井技术。 为了对双台阶水平井钻井质量进行有效评价,研制了一套完善的双台阶水平井钻井实时跟踪系统。该系统充分结合导眼井及邻井的地质、钻井、录井、测井及随钻测井等多种资料,实现双台阶水平井钻井的实时跟踪,对井眼轨迹位移及钻遇地层进行实时分析,计算钻遇率。利用该系统在哈得油田某井区双台阶水平注水井HD10-HX井现场进行了初步的钻井实时跟踪分析应用,获得了较好的应用效果。