多发颈椎不连综合征的影像学特点与外科诊疗策略

【摘要】 目的：分析多发颈椎不连综合征（multilevel cervical disconnection syndrome,MCDS）的影像学特点及外科诊疗策略。方法：2004年3月~2021年6月,我院收治MCDS患者共7例,男性3例,女性4例;年龄5~46岁（中位年龄12岁）。7例MCDS患者中,平均椎体发育不良节段数3.6±1.3个节段,平均椎弓不连节段数5.7±1.5个节段,局部后凸角平均-92.2°±20.2°,C2-7 Cobb角平均-68.6°±31.0°,T1倾斜角（T1 slope,T1S）平均-12.5°±12.5°,后凸顶点位于C4节段1例,C5节段5例,T1节段1例;术前改良日本骨科学会评分（mJOA评分）8.5~14分（平均12.6±2.1分）,其中1例患者伴有吞咽困难。记录患者预矫形方式及手术方式,入院时、预矫形后、术后及末次随访影像学参数,神经功能及并发症。结果：1例术前接受颅骨牵引,3例接受平衡悬吊牵引,3例接受联合牵引,经术前牵引预矫形后,局部后凸角矫正率为60.8%。1例接受手术松解、Halo-vest外固定治疗,1例接受前路矫形内固定手术,1例接受后路矫形固定融合术,4例接受前-后联合手术治疗,手术固定6.0±2.1个节段,2例患者出现术后神经系统并发症,接受翻修手术。术后随访时间6~84个月（41.2±32.0个月）,末次随访局部后凸角平均-27.9°±11.6°,矫正率69.7%,C2-7 Cobb角平均-13.3°±28.4°,T1S平均4.9°±17.9°;术后mJOA评分10.5~17分（15.7±2.3分）,改善率78.3%。对比手术前后临床及影像学指标,mJOA评分、C2-7后凸角、局部后凸角及T1S有统计学差异。结论：MCDS影像学上主要表现为前方椎体发育不良伴多节段椎弓不连,继发严重后凸畸形。治疗策略可采取术前牵引预矫形并前路多节段椎体切除重建、后路长节段固定融合。     

颈前路经椎间隙行钩椎关节松解治疗退变性颈椎后凸畸形的疗效分析

【摘要】 目的：探讨颈前路减压植骨融合内固定术中行钩椎关节松解治疗退变性颈椎后凸畸形的疗效。方法： 回顾性分析2017年1月~2019年1月在我院行颈前路减压植骨融合内固定术且在术中经椎间隙行钩椎关节松解治疗的41例退变性颈椎后凸畸形患者,其中男17例,女24例;年龄64.8±9.7岁。僵硬性后凸24例,非僵硬性后凸17例,对僵硬性颈椎后凸畸形患者行双侧钩椎关节切除松解。手术节段为2个节段的患者3例（C3~C4,1例;C4~C6,2例）,3个节段患者28例（C3~C6,11例;C4~C7,17例）,4个节段患者10例（C3~C7,10例）。术前及末次随访通过日本骨科学会（Japanese Orthopaedic Association,JOA）评分、颈椎功能障碍指数（neck disability index,NDI）、颈痛及根性疼痛的视觉模拟评分法（visual analogue scale,VAS）评分评估患者神经功能变化。收集患者术前及末次随访时颈椎X线片,测量C2~C7 Cobb角、手术节段Cobb角及C2~C7矢状位轴向垂直距离（sagittal vertical axis,SVA）。采用配对样本t检验对手术前后神经功能及影像学资料进行统计分析,并统计患者术后并发症发生情况。结果：所有患者手术顺利,手术时间124~210min（162.5±28.6min）,术中出血量70~200ml（121.1±34.2ml）,随访时间35.5±7.7个月（24~48个月）。所有患者术后神经功能均得到明显改善,术前JOA评分10.7±2.4分,末次随访15.6±1.3分,差异有统计学意义（P＜0.05）,改善率（75.5±27.4）%（0~100%）;术前NDI为24.4±7.9分,末次随访8.7±3.9分,差异有统计学意义（P＜0.05）,改善率（65.7±21.4）%（30%~100%）;术前VAS评分4.3±1.9分,末次随访1.9±1.3分,差异有统计学意义（P＜0.05）。患者颈椎矢状面参数明显改善,术前颈椎整体Cobb角（C2~C7）为-16.5°±5.3°,末次随访10.2°±5.1°（P＜0.05）;SVA由术前33.2±13.7mm改善至末次随访时17.5±7.8mm（P＜0.05）;手术节段Cobb角术前为-19.8°±5.7°,末次随访为11.3°±2.2°（P＜0.05）。围手术期并发症4例,颈部血肿1例,声音嘶哑1例,轻度吞咽困难2例,患者经保守治疗后症状缓解;18例患者在末次随访时出现邻近节段退变的影像学表现。结论：采用颈前路减压植骨融合内固定术并在术中经椎间隙行钩椎关节松解治疗退变性颈椎后凸畸形可以获得满意的临床效果,重建颈椎曲度及颈椎矢状位平衡。     

颈椎椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术治疗多节段压迫性颈脊髓病合并退变性颈椎后凸的中长期疗效

【摘要】 目的：观察颈后路椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术治疗多节段压迫性颈脊髓病合并退变性颈椎后凸患者的中长期疗效。方法：回顾性分析2008年3月~2019年9月，采用颈后路单开门椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术治疗的18例多节段脊髓受压的慢性颈脊髓病合并退变性颈椎后凸患者，其中男11例，女7例，年龄52.3±8.1岁；颈椎后纵韧带骨化症（ossification of posterior longitudinal ligament，OPLL）合并慢性颈脊髓病5例，脊髓型颈椎病13例。减压节段：17例为C3~C7，1例为C3~T1，术中固定融合3.8±1.0个椎体。12例患者出院时（术后2周左右）复查颈椎MRI，11例患者获得随访，随访时间2.1~13.5年（10.5±2.8年）。在术前、出院时颈椎侧位X线片上测量后凸节段Cobb角，在颈椎MRI上测量脊髓前缘角及改良K线，末次随访时在X线片上评估手术固定节段骨性融合及后凸矫形角度丢失情况。术前及末次随访时进行JOA评分及颈痛VAS评分。结果：18例患者术前后凸节段的局部Cobb角为6.6°±6.5°后凸，术后2周为3.8°±8.0°前凸，有显著性差异（P<0.01）； 术前C2~C7颈椎Cobb角为1.3°±9.4°前凸，术后2周为5.8°±7.0°前凸，无显著性差异（P＞0.05）。12例患者颈椎MRI上测量脊髓前缘角术前为11.1°±4.2°后凸，术后2周为1.3°±5.2°后凸，有显著性差异（P<0.01）；C2~C7节段脊髓前缘角术前为6.5°±4.4°后凸，术后2周为1.1°±6.3°前凸，有显著性差异（P<0.01）。7例（39%）患者术后出现C5神经根麻痹，均在术后1~4个月内完全恢复。术后末次随访11例患者颈椎侧位X线片显示手术固定节段均获骨性融合，后凸矫形角度无丢失；颈椎MRI显示脊髓无受压，正中矢状位片显示脊髓前缘角无丢失。11例患者JOA评分术前8.0±2.8分，末次随访时15.6±0.9分，有显著性差异（P<0.01），JOA评分改善率（83±14）%；颈痛VAS评分术前为2.2±3.0分，末次随访时为1.1±1.2分，术前与末次随访时相比无显著性差异（P>0.05）。结论：对于合并有退变性颈椎后凸的多节段受压的慢性压迫性颈脊髓病，采用椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术可以获得长期稳定、良好的脊髓功能改善的效果。     

双椎体截骨术矫正强直性脊柱炎重度胸腰椎后凸畸形

【摘要】 目的：观察双椎体经椎弓根楔形截骨矫正强直性脊柱炎重度胸腰椎后凸畸形的治疗效果。方法：2009年5月～2010年12月我院采用双椎体经椎弓根楔形截骨、椎弓根螺钉内固定术治疗强直性脊柱炎重度胸腰椎后凸畸形患者18例,均为男性,年龄19～47岁,平均34.8岁。术前全脊柱最大后凸Cobb角70°~108°（82.6°±17.5°）,顶椎均位于胸腰段;胸椎后凸角46°~67°（55.2°±15.3°）,胸腰段后凸角25°~43°（32.4°±12.6°）,腰椎前凸角-37°~-11°（-19.5°±10.3°）;站立位颌眉角43°～130°（67.2°±21.9°）;侧位X线片上C7铅垂线距S1后上角的距离为11～35cm（18.3±14.8cm）。采用Bridwell-Dewald脊柱疾患疼痛及功能评定标准进行手术前后疗效评价。结果：手术时间为5.3±1.0h（3.7～6.9h）,术中出血量1887.5±850.9ml（600～3000ml）。术中硬膜破裂4例,术后伤口表浅感染1例,一侧下肢神经症状1例,经治疗后均恢复良好。随访24～48个月,平均33.5个月。术后1周时测量,全脊柱最大后凸Cobb角矫正到21.3°±4.2°,颌眉角改善到9.3°±12.8°,C7铅垂线距S1后上角的距离改善到3.0±4.7cm;术后1周全脊柱最大后凸Cobb角、胸椎后凸角、胸腰段后凸角、腰椎前凸角、颌眉角和C7铅垂线距S1后上角距离均较术前明显改善（P<0.05）。末次随访时,上述指标与术后1周比较差异无统计学意义（P>0.05）;X线片显示所有患者内固定位置良好。患者能平视行走,末次随访时疼痛、工作限制情况及社交限制情况较术前明显改善（P<0.05）。结论：对强直性脊柱炎严重胸腰椎后凸畸形患者,应用双椎体经椎弓根楔形截骨术治疗是一种安全、有效的方法,可较好地恢复脊柱矢状位生理曲度。     

后路全脊椎截骨矫形术治疗重度胸腰椎角状后凸/侧后凸的中远期效果观察

【摘要】 目的：评价中重度胸腰椎角状后凸/侧后凸畸形行后路全脊椎截骨矫形术患者的中远期影像学和临床疗效。方法：总结2004年5月～2016年6月于我院行后路全脊椎截骨矫形术（posterior vertebral column resection,PVCR）的68例中重度胸腰椎角状后凸/侧后凸患者的临床资料,其中男性37例,女性31例,平均年龄36.89±15.38岁。45例患者术前存在下肢神经症状,Frankel分级A级1例,B级2例,C级9例,D级33例。病因诊断：结核性后凸50例,先天性后凸18例。所有患者均行手术前后和随访时的后凸局部和全脊柱X线、CT、MRI检查,确定后凸顶点,并测量后凸角度。对合并侧凸的21例患者测量侧凸角度。在全脊柱X线片上评价患者的矢状位和冠状位平衡状况。临床评价包括下肢神经功能的Frankel分级,生活质量的Oswestry功能障碍指数（Oswestry disability index,ODI）,腰背部疼痛的视觉模拟评分（visual analogue score,VAS）,以及患者的手术治疗满意度（patient satisfactory index,PSI）。将患者依照年龄、后凸病因、后凸严重程度（后凸角度）、后凸顶椎节段、术前Frankel分级和有无并发症分组,进行影像学和临床结果比较,并对随访ODI评分改善率的影响因素进行多元回归分析。结果：患者平均随访时间为41.47±4.68个月（36～96个月）。患者术前平均后凸角度94.14°±22.57°（60.0°～155.2°）,术后减少至31.92°±16.79°,末次随访时为34.60°±18.09°,后凸矫正率为（64.26±15.13）%。21例同时伴有侧凸的患者术前平均侧凸角度37.36°±26.19（12.0°～107.0°）,术后减少至13.21°±14.72°,末次随访时为14.33°±14.93°,侧凸矫正率为（69.70±28.44）%。末次随访时,30例患者Frankel分级改善,3例患者从A级或B级提高到C级,5例患者从C级提高到D级,1例患者从C级提高到E级,21例患者从D级提高到E级。术后平均ODI改善率为（48.82±33.99）%,平均VAS改善率为（64.03±21.42）%;患者PSI为91.2%。对后凸矫正率、ODI改善率的单因素分析结果提示,后凸角度小于95°和年龄小于35岁时,后凸矫正率更高;当患者角状后凸顶点位于T10或以下,术前双下肢无神经症状,或围手术期无并发症发生时,其临床改善率更高。多因素回归分析结果发现,术前后凸角越小,随访时后凸角矫正度数越大,术前Frankel分级为D或E级,其ODI改善率越高。中远期发生内固定失败6例（8.8%）,均行翻修手术。结论：后路全脊椎截骨矫形术是治疗胸腰椎中重度角状后凸/侧后凸畸形的一种有效、安全的方法,中长期随访结果发现患者可获得满意的畸形矫正效果以及良好的神经功能改善。     

改良式颈前路椎间盘切除减压融合术治疗退变性颈椎后凸患者的疗效分析

【摘要】 目的：探讨颈前路经椎间隙扩大减压融合术（anterior trans-intervertebral space decompression and fusion,ATIDF）治疗退变性颈椎后凸患者的临床疗效。方法：回顾性分析2017年6月～2019年6月在我科接受ATIDF手术治疗的65例退变性颈椎后凸患者的临床资料。其中男性37例,女性28例;年龄63.4±11.2岁（35～85岁）,病程18.2±8.4个月（4~28个月）。接受两节段ATIDF患者16例（C3~C5 7例、C4~C6 9例）,三节段ATIDF患者38例（C3~C6 18例、C4~C7 20例）,四节段ATIDF（C3~C7）患者11例。纳入患者中僵硬型后凸患者35例（53.85%）,柔韧性后凸患者30例（46.15%）;僵硬型后凸患者在减压时均采用了部分钩椎关节切除。分别于术前、术后第2天及末次随访时采用日本骨科学会（Japanese Orthopedic Association,JOA）评分、颈椎功能障碍指数（neck disability index,NDI）及疼痛视觉模拟评分（visual analogue scale,VAS）对患者的神经功能和疼痛情况进行评估;拍摄颈椎正侧位及动力位X线片评价颈椎曲度（C2~C7 Cobb角）、手术节段Cobb角、手术节段椎间隙高度、C2~C7矢状位轴向垂直距离（sagittal vertical axis,SVA）,并计算后凸的矫正率。采用颈椎MRI平扫和CT评估患者神经减压情况和植骨融合情况。记录纳入患者随访期间相关并发症出现情况。结果：纳入患者随访时间为33.5±5.4个月（24~50个月）。手术时间为158.2±31.4min（105~215min）,术中出血量为117.6±36.3ml（65~200ml）。纳入患者均取得了满意的神经功能改善,术后和末次随访时JOA评分、NDI和VAS评分均较术前明显改善（P＜0.05）。所有纳入患者术后颈椎后凸角度均取得一定程度的改善,后凸矫正率为147.43%。术后第2天和末次随访时C2~C7 Cobb角、手术节段局部Cobb角较术前明显增加（P＜0.05）,SVA较术前明显改善（P＜0.05）。手术节段的平均椎间隙高度从术前的2.14±1.53mm增加至术后第2天的5.94±3.11m（P=0.001),末次随访时为5.36±2.47mm（P=0.001)。随访期间有8例（12.31%）患者出现颈部轴性症状,术后第2天有33例（50.77%）患者主诉吞咽困难,3例（4.62%）患者出现C5神经根麻痹,经对症处理后均改善。结论：ATIDF治疗退变性颈椎后凸可取得满意的临床疗效和后凸矫正,对于存在严重椎间隙狭窄、钩椎关节增生的僵硬型颈椎后凸具有良好的矫形和减压作用。     

退变性脊柱侧凸的选择性手术治疗

【摘要】 目的 评价选择性手术治疗退变性脊柱侧凸的临床疗效。 方法 2005年1月~2009年9月共手术治疗22例患者。记录所有患者术前、术后3个月及末次随访时的Oswestry功能评分;记录实施内固定治疗患者术前、术后3个月及末次随访时的侧凸Cobb角、腰椎前凸角以及融合时间。 结果 平均随访19个月（8~36个月）。椎管减压3例;椎管减压并内固定植骨融合术19例,其中长节段固定6例。Oswestry功能评分术前为39.25±10.47,术后3个月为13.85±7.73,末次随访时为17.95±6.18。实施内固定的患者侧凸Cobb角术前为21.05°±8.51°,术后3个月为12.13°±4.83°,末次随访时为14.03°±5.25°;腰椎前凸角术前为 14.40°±14.72°,术后3个月为26.62°±11.48°,末次随访时为24.27°±11.03°;术后6个月,均达到骨性融合。上述各组术后3个月及末次随访的数据与术前比较差异均有统计学意义（P＜0.05）。 结论 退变性脊柱侧凸的治疗主要以缓解症状为目的,依据不同的临床及影像学表现制定个体化治定方案能够取得满意的临床疗效。     

重度僵硬型脊柱侧凸的一期后路Ponte截骨置钉二期后路矫形术

 目的 探讨一期后路Ponte截骨置钉二期后路矫形在治疗重度僵硬型脊柱侧凸中的疗效及安全性。方法 回顾性分析2010年6月至2012年12月接受一期后路Ponte截骨二期后路矫形治疗的Cobb角大于100°的僵硬型脊柱侧凸患者24例,男9例,女15例;年龄14~30岁,平均（21.4±4.1）岁。术前冠状面主弯Cobb角106°~156°,平均125.8°;后凸角59°~141°,平均100.1°。一期后路Ponte截骨松解、置钉,术后Halo-股骨髁上牵引,再行二期后路置棒矫形融合术。比较术前站立位、后路松解牵引后仰卧位、术后及末次随访的冠状面主弯Cobb角。结果 术前仰卧Bending位主弯侧凸柔韧性为14.8%±7.5%;后路松解牵引后主弯侧凸柔韧性为29.1%±9.9%;较术前平均提高14.3%,差异有统计学意义。后路矫形术后主弯Cobb角平均74.4°±14.5°,矫正率平均41.0%±8.1%;与术前仰卧Bending位和松解牵引后比较矫正率分别提高了26.2%和11.9%,差异有统计学意义。术后随访15~36个月,平均（24.0±5.9）个月。末次随访时主弯Cobb角平均丢失1.4°。术后后凸角平均53.0°±13.7°,较术前（100.1°±23.7°）明显改善,矫正率平均46.1%±11.9%,末次随访时无矫正丢失。牵引中1例发生左侧股骨髁上钉道感染,2例发生左下肢静脉血栓。结论 后路Ponte截骨松解+Halo-股骨髁上牵引能够使重度僵硬型脊柱侧凸患者获得满意的矫正率,但应注意下肢静脉血栓形成的风险。     

一期前后路联合手术在治疗颈椎疾病中的应用

目的探讨一期前后路联合手术在颈椎疾病治疗中的适应证和作用。方法对22例颈椎术后继发僵硬后凸畸形、多节段颈椎管狭窄、后纵韧带钙化、严重骨折脱位和颈椎结核患者行一期前后路联合减压、植骨融合、内固定手术。结果22例随访13～32个月(平均15.6个月),植骨均已融合,内固定物无松动、断裂。除2例完全截瘫无恢复外,余20例JOA评分由术前9.3分(5～13分)增加到13.4分(8～17分);7例颈椎术后继发僵硬后凸畸形患者C2～C7Cobb角由术前后凸18.4°(11.5°～21.5°),术后恢复为前凸8.2°(4.0°～12.5°)。术后短期并发症均逐渐恢复;1例食管瘘患者经手术修补也顺利愈合。结论一期前后联合手术减压充分,能较好重建颈椎稳定性。     

不对称经椎弓根截骨矫治成人先天性脊柱侧后凸畸形

【摘要】 目的：分析应用不对称经椎弓根截骨技术矫治成人先天性脊柱侧后凸畸形的临床疗效。方法：2009年9月~2013年10月采用不对称经椎弓根截骨矫治成人先天性脊柱侧后凸畸形患者16例,男9例,女7例。年龄18～42岁,平均23.6岁。均有腰背痛,无神经受压症状。16例患者脊柱侧凸Cobb角43°~97°,后凸Cobb角15°~70°。侧凸畸形和后凸畸形顶椎均位于同一节段,其中顶椎位于胸椎10例、腰椎6例。于术前、术后及末次随访时在X线片上测量脊柱冠状面主弯Cobb角、矢状面后凸角、冠状面平衡及矢状面平衡,比较术前、术后及末次随访时影像学参数评估手术矫形效果。于术前、末次随访时填写SRS-22问卷量表,评估患者术后的生活质量变化。结果：手术融合节段5~12个,平均7.23个节段。手术时间3~7h,平均4.26h。术中出血量700～2500ml,平均1265ml。1例L1部位截骨患者术后出现双下肢痛觉过敏,急诊手术探查发现截骨部位硬脊膜皱褶,脊髓受压,对截骨部位椎板切开减压,术后症状明显好转,术后3个月随访神经症状消失。2例患者术后出现一侧胸腔积血,紧急行胸腔闭式引流术,1周后拔除引流管。15例患者获得6～48个月（平均13.4个月）随访。获得随访的15例患者冠状位主弯Cobb角术前为58.67°±20.36°（43°～97°）,术后为20.32°±8.76°（8°～37°）,末次随访时为21.76°±8.34°（10°～41°）,术后与术前比较差异有统计学意义（P<0.01）,矫正率为50.76%~82.36%,平均为65.36%,末次随访时与术后比较丢失率为2.45%。术前矢状位后凸角度为45.62°±16.26°（15°～70°）,术后为16.35°±16.87°（-20°～40°）,末次随访时为18.27°±13.92°（-15°～40°）,术后与术前比较差异有统计学意义（P<0.01）,矫正率为50.97%~79.32%,平均为64.16%,末次随访时与术后比较丢失率为4.2%。15例患者中,6例术前存在冠状面失平衡,术后均恢复平衡;4例术前存在矢状面失平衡,术后3例恢复平衡,1例仍为失平衡。SRS-22问卷量表总得分由术前66.47±12.35分（49～79分）提高至末次随访时的84.13±6.42分（76～92分）（P<0.01）。15例患者均获得骨性融合,无假关节形成或内固定断裂。结论：应用不对称经椎弓根截骨技术矫治先天性脊柱侧后凸畸形,可获得较好的矫形效果,显著改善患者躯体外观及躯体平衡,同时明显改善患者的生活质量。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.