青少年L5滑脱患者脊柱-骨盆矢状面形态的特征及临床意义

目的:研究青少年L5滑脱患者的脊柱-骨盆矢状面形态,分析不同类型滑脱的矢状面参数特征及临床意义。方法:回顾性分析2010年1月～2019年12月在我院就诊的资料完整的青少年L5滑脱患者36例,男、女各18例,平均年龄14.1±2.5岁(10～18岁);按照Wiltse滑脱分型分为峡部裂组28例和发育不良组8例;按照Meyerding分度标准分为轻度滑脱组32例(Ⅰ度29例、Ⅱ度3例)和重度滑脱组4例(Ⅲ度2例、Ⅳ度2例)。在站立位全长脊柱侧位片上测量脊柱-骨盆矢状面参数。其中滑移参数包括:滑脱率(slip rate,SR)、滑脱角(slip angle,SA);骨盆矢状面参数包括:骨盆入射角(pelvic incidence,PI)、骨盆倾斜角(pelvic tilt,PT)、腰骶角(lumbosacral angle,LSA)、骶骨平台角(sacral table angle,STA);脊柱矢状面参数包括:胸椎后凸角(thoracic kyphosis,TK)、腰椎前凸角(lumbar lordosis,LL)和矢状垂直偏距(sagittal vertical axis,SVA)。对比研究峡部裂组和发育不良组以及轻度和重度滑脱患者的脊柱-骨盆矢状面参数特点和相关临床意义。结果:峡部裂组SR=(13.7±8.1)%,PT=15.7°±8.3°,LSA=105.9°±11.8°,STA=102.8°±6.5°;发育不良组SR=(42.4±27.8)%,PT=34.2°±9.6°,LSA=78.7°±11.2°,STA=76.4°±9.5°;两组相比具有显著的统计学差异(P0.05)。轻度滑脱组SR=(14.4±7.8)%,PT=18.1°±10.4°,LSA=102.1°±15.5°,STA=99.9°±10.8°;重度滑脱组SR=(65.0±19.6)%,PT=33.9°±11.1°,LSA=77.4°±6.7°,STA=77.7°±8.8°,两组相比具有显著的统计学差异(P0.05)。峡部裂组SA=2.6°±13.1°,PI=54.6°±9.0°,TK=23.5°±15.5°,LL=-53.0°±18.3°;发育不良组SA=11.2°±10.5°,PI=60.8°±14.5°,TK=21.5°±14.3°,LL=-45.3°±15.9°;两组相比无统计学差异(P0.05)。轻度滑脱组SA=3.3°±12.6°,PI=55.3°±10.4°,TK=24.0°±13.1°,LL=-52.7°±17.4°;重度滑脱组SA=14.5°±12.8°,PI=61.0°±12.2°,TK=14.8°±3.7°,LL=-40.0°±20.0°,两组相比无统计学差异(P0.05)。结论:青少年L5滑脱中,发育不良性多为重度滑脱,而峡部裂性多为轻度滑脱。发育不良性重度滑脱容易出现矢状面失衡和滑脱进展,其脊柱-骨盆矢状面呈现躯干前倾,骶骨垂直和骨盆后倾的形态。     

青少年L5/S1发育不良性滑脱患者的骶骨矢状面形态

目的 :研究青少年L5/S1发育不良性滑脱患者的骶骨矢状面形态。方法 :回顾性分析2002年5月~2016年3月入院手术治疗的13例青少年L5/S1发育不良性滑脱患者,男2例,女11例,年龄12.2±3.1岁(9~18岁)。以年龄匹配的30例正常青少年为对照组。在站立位全脊柱侧位X线片上测量骶骨形态、姿势等参数。采用独立样本t检验对滑脱组和对照组以及滑脱组内低度发育不良亚组和高度发育不良亚组的各参数进行对比分析。结果:滑脱组患者中,10例存在S1上终板拱顶样改变,6例L5椎体楔形变,9例L5-S1后凸成角畸形。其腰骶角、骶骨平台角和S1指数均显著低于对照组;骶骨形态也异于对照组,骶骨角和S1上角显著小于对照组,骶骨头端(S1)曲度减小,然而骶骨的整体后凸角度显著大于对照组(Cobb法:50.1°±10.6°比18.1°±10.4°;Ferguson法:40.5°±9.9°比23.1°±11.5°)。滑脱组矢状面平衡显著大于对照组(46.5±42.3mm比-25.6±21.8mm),且其骨盆入射角、L5入射角、骨盆倾斜角、骨盆矢状面厚度均显著大于对照组(P0.01),而骶骨倾斜角却显著小于对照组(P0.05)。滑脱组呈现出躯干明显前倾、骨盆后旋、骶骨直立的姿态。滑脱组中高度发育不良8例,低度发育不良5例。高度发育不良组与低度发育不良组相比,其滑脱程度、骶骨后凸角及矢状面轴向垂直距离均显著增大[(67.3±18.6)%比(45.4±12.5)%;45.8°±8.4°比32.2°±5.1°;52.6±24.7mm比21.6±9.5mm(P0.05)。结论:青少年L5/S1发育不良性腰椎滑脱患者除腰骶局部发育不良外,骶骨呈明显后凸形态。因躯干前倾,骨盆后旋和骶骨垂直化以代偿矢状面失衡,而这些异常形态受发育不良程度影响。     

马凡综合征伴脊柱畸形患者脊柱-骨盆矢状面的形态特征

目的:探索马凡综合征伴脊柱畸形患者脊柱-骨盆矢状面的形态特征。方法:收集以脊柱畸形来我院就诊的马凡综合征患者35例,男18例,女17例,年龄10~20岁,平均14.4±2.3岁。在站立位全脊柱侧位X线片上测量脊柱及骨盆矢状面参数,包括:(1)胸椎后凸角(thoracic kyphosis,TK),(2)胸腰段后凸角(thoracolumbar kyphosis,TL),(3)腰椎前凸角(lumbar lodorsis,LL),(4)骨盆入射角(pelvic incidence,PI),(5)骨盆倾斜角(pelvic tilt,PT),(6)骶骨倾斜角(sacral slope,SS),(7)矢状面平衡(sagittal vertical axis,SVA)。定义顶椎在T12、L1或者T12/L1椎间盘,后凸角度10°的后凸为胸腰段后凸;顶椎在L1/2椎间盘或以下椎体、椎间盘,后凸角度10°的后凸为腰椎后凸。采用Sponseller分型方法对患者脊柱矢状面形态进行分型,比较不同分型患者脊柱-骨盆矢状面形态。结果:本组患者在冠状面上以胸腰双弯(40.0%)、单胸弯(22.8%)以及三弯(20.0%)最常见,最大Cobb角43°~165°,平均75.2°±26.0°。在脊柱矢状面上,TK为-25°~73°(19.0°±24.1°),其中胸椎后凸正常者(20°≤TK≤50°)10例(28.6%);胸椎后凸增大患者(TK50°)5例(14.3%);胸椎后凸减小者(0°≤TK20°)13例(37.1%);另有7例(20.0%)患者表现为胸椎前凸。TL为-25°~73°(14.0°±19.0°);LL为-17°~70°(37.1°±23.3°);SVA为-9.0~7.2cm(-2.0±4.3cm)。15例(42.9%)患者表现为胸腰段后凸或腰椎后凸(9例ⅡA型,6例ⅡB型),5例患者表现为后凸区明显的椎体楔形变。骨盆矢状面上,PI为25°~74°(40.1°±12.7°);PT为-12°~34°(6.9°±9.6°);SS为14°~68°(33.3°±12.6°)。Sponseller分型Ⅰ型患者TK、LL、PI、SS明显大于Ⅱ型患者,而Ⅱ型患者TL明显大于Ⅰ型患者。未见腰椎滑脱现象。结论:马凡综合征伴脊柱畸形患者脊柱-骨盆矢状面形态差异较大,手术医生应该根据不同分型制定不同的手术策略。     

L_4 退变性滑脱患者脊柱-骨盆矢状面参数的特点与相关性分析

[目的]探讨L4退变性滑脱患者脊柱-骨盆矢状面参数的特点及各参数之间的相关性。[方法]回顾性分析2011年1月~2014年6月间44例L4单节段退变性滑脱患者的临床资料,并选取41例健康志愿者做为对照。在站立位脊柱侧位X线片上进行矢状面参数的测量(包括骨盆入射角PI、骨盆倾斜角PT、骶骨倾斜角SS、腰椎前凸角LL、矢状面轴向垂直距离SVA及T1骨盆角TPA等)。按PI大小进行分组对比,并观察腰椎矢状面曲度的Roussouly分型。[结果]DS组的PI、PTNC组,SSNC组(P0.05);两组的LL、SVA及TPA差异无统计学意义(P0.05)。在DS组中进一步发现:正常PI亚组的PT、TPA均大于NC组及大PI亚组的相应值,而SS均小于NC组及大PI亚组(P0.05)。按Roussouly分型,NC组中1~4型所占比例分别为9.8%、56.1%、26.8%和7.3%;DS组中1~4型的比例分别为4.5%、25%、43.2%和27.3%。相关性分析显示:两组中均可见PI与PT、SS存在密切相关性(P0.05);而TPA与PI、PT、LL及SVA之间有密切相关性(P0.05)。[结论]L4退变性滑脱患者较正常人群的骨盆入射角更大,且存在骨盆后倾的代偿机制;T1骨盆角是评价患者整体矢状面平衡的理想指标。     

儿童发育不良性重度腰椎滑脱手术复位后脊柱-骨盆矢状位序列改变

目的 :评估手术复位对儿童L5发育不良性重度滑脱患者脊柱-骨盆矢状位序列的影响。方法:回顾性分析13例行手术复位治疗的儿童L5发育不良性重度滑脱患者,其中男2例,女11例。均行减压复位内固定融合术。手术时年龄11.5±2.4岁(7~15岁)。采用配对样本t检验比较术前、末次随访时的滑脱程度(slip degree)、腰椎前凸角(lumbar lordosis,LL)、Boxall滑脱角(Boxall′s slip angle,BSA)、SDSG发育不良性腰骶角(Spinal Deformity Study Group dysplastic lumbosacral angle,SDSG-dys LSA)、骨盆投射角(pelvic incidence,PI)、骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacral slope,SS)的差异,评估手术复位后脊柱-骨盆矢状位序列的变化。结果:随访20.6±21.9个月(3~64个月),滑脱程度由术前的(76.01±15.65)%改善至末次随访时的(17.57±16.64)%(P0.01),滑脱复位程度为(58.44±16.31)%,其中4例Ⅲ度滑脱患者完全复位。11例患者行S1上终板拱顶样部分切除,平均切除程度为(30.16±14.54)%。术前、末次随访时的LL分别为74.75°±18.11°、57.77°±14.83°,BSA分别为48.98°±16.01°、19.56°±18.70°,SDSG-dys LSA分别为19.78°±20.19°、-1.72°±19.04°,SS分别为28.68°±23.21°、41.13°±15.67°,末次随访时均较术前有显著性改变(P0.05);PI分别为65.64°±19.88°、73.20°±18.85°,PT分别为36.88°±11.68°、32.03°±11.76°,末次随访时较术前无显著性改变(P0.05)。C7铅垂线距骶骨后上角距离(sagittal vertical axis,SVA)较术前减小。末次随访时10例后倾型骨盆患者中2例(20%)转变为平衡型骨盆。结论:手术复位可改善儿童L5发育不良性重度滑脱患者脊柱-骨盆矢状位序列,矫正腰骶部后凸畸形,改善骶骨-骨盆矢状位序列。     

青少年L5/S1峡部裂性腰椎滑脱患者脊柱-骨盆矢状面形态分析

目的探讨青少年L_5/S_1峡部裂性腰椎滑脱患者的脊柱-骨盆矢状面形态改变。方法回顾性分析2009年10月—2017年1月收治的29例青少年L_5/S_1峡部裂性腰椎滑脱患者影像学资料,以30例年龄匹配的正常青少年影像学资料作为对照。在站立位全脊柱侧位X线片上测量滑脱角(SA)、滑脱距离(SD)、骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)、骨盆矢状面厚度(SPT)、L_5入射角(L_5I)、腰椎前凸角(LL)、胸椎后凸角(TK)、脊柱矢状位平衡(SVA)、骶骨平台角(STA)、S_1指数、腰骶角(LSA)等脊柱-骨盆矢状面参数,并计算滑脱率(SP),比较滑脱组与对照组以及低滑脱(SP≤17%)与高滑脱(SP17%)亚组之间的差异,并采用Pearson相关检验分析SP与各影像学参数的相关性。结果滑脱组SA为-4.5°±9.6°,SD为(7.1±3.6)mm,SP为(22.2±11.1)%。滑脱组的LSA、STA、S_1指数小于对照组,PI、PT、SS、SPT、L_5I、SVA及LL大于对照组,差异均有统计学意义(P0.05);2组TK差异无统计学意义(P0.05)。高滑脱亚组的SA、TK、LSA、STA及S_1指数均显著小于低滑脱亚组,PI、PT、SS、SPT、L_5I和SVA均大于低滑脱亚组,差异均有统计学意义(P0.05);2个亚组的LL差异无统计学意义(P0.05)。滑脱组PI、PT、SPT、L_5I、LL与SP呈正相关,TK、LSA、STA及S_1指数与SP成负相关,SS、SVA与SP无明显相关性。结论腰骶部先天发育不良可能是青少年峡部裂性腰椎滑脱发生的始动因素。受滑脱程度影响,其脊柱-骨盆矢状面形态显著异常,表现出腰椎前凸增大、躯干前倾,同时骨盆后旋、屈髋屈膝等异常代偿姿势。     

高度发育不良性腰椎滑脱复位程度与脊柱-骨盆矢状位参数变化的关系

目的 :分析高度发育不良性腰椎滑脱(high dysplastic developmental spondylolisthesis,HDDS)的手术复位程度与脊柱-骨盆矢状位参数变化的关系,以了解复位至何种程度能够显著改善术后脊柱-骨盆矢状位序列。方法:回顾性分析2007年3月～2019年4月在我院骨科接受手术治疗的35例HDDS患者,滑脱节段均为L5,年龄14.9±5.9岁(9～35岁)。均行减压、部分复位或完全复位、椎弓根螺钉内固定融合术。随访42.5±33.1个月(3～120个月)。依据术后末次随访时的Dubousset腰骶角(Dubousset lumbosacral angle,Dub-LSA)将患者分为70°(7例)、70°～79.9°(8例)、80°～89.9°(4例)及≥90°(16例)四组,依据末次随访时滑脱的Meyerding分度将患者分为Ⅲ度及以上(5例)、Ⅱ度(6例)、Ⅰ度以内(24例)三组,分别对比各组的术前、末次随访时脊柱-骨盆参数的变化。结果:滑脱率术前为(66.7±22.5)%(35%～100%),末次随访时为(18.9±20.9)%(0%～72%);DubLSA术前为61.9°±14.7°,末次随访时82.1°±17.3°。末次随访时Dub-LSA越大、滑脱程度越低,脊柱-骨盆矢状位参数较术前改善越明显;直至Dub-LSA≥90°和滑移程度在Ⅰ度以内时,骨盆倾斜角(pelvic tilt,PT)和骶骨倾斜角(sacral slope,SS)均有显著性改善,由后倾型骨盆转变为平衡型骨盆的比例显著增加。Dub-LSA≥90°组术前与末次随访时PT分别为36.4°±6.5°与27.2°±4.9°(P0.001)、SS分别为33.5°±9.1°与42.1°±9.3°(P0.001)、平衡型骨盆比例分别为0%(0/16)与43.8%(7/16)(P=0.007),末次随访时与术前比较均有统计学差异。末次随访时滑脱程度在Ⅰ度以内组,术前与末次随访时PT分别为38.9°±8.6°与30.6°±7.4°(P0.001)、SS分别为31.4°±11.5°与41.2°±8.7°(P0.001)、平衡型骨盆比例分别为0%(0/24)与29.2%(7/24)(P=0.009),末次随访时与术前比较均有统计学差异。结论:将HDDS患者的Dub-LSA复位至≥90°和将滑移复位至Ⅰ度以内能够显著改善脊柱-骨盆矢状位参数,并且能够将部分(43.8%)后倾型骨盆改善为平衡型骨盆。     

退变性腰椎侧凸脊柱-骨盆矢状位影像学特点

目的 :观察退变性腰椎侧凸(DLS)患者脊柱-骨盆矢状位影像学特点,探讨脊柱-骨盆矢状位参数变化对DLS发生的影响。方法:回顾性分析103例DLS患者术前资料,男36例,女67例,年龄62.6±7.4(43~78)岁,并选取139例正常青年人群作为正常青年对照组,145例单纯颈椎病患者作为成年对照组,在脊柱全长正侧位X线片上测量各组冠状位、矢状位参数,包括L3倾斜角、侧凸Cobb角、冠状位平衡(CVA)、腰椎前凸角(LL)、矢状位平衡(SVA)、胸椎后凸角(TK)、骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)等,采用独立样本t检验比较DLS组与两对照组的各矢状位参数,并用Pearson相关分析DLS组各参数间相关性。结果:DLS组PI为50.4°±10.2°,显著高于正常青年对照组(45.1°±9.6°,P0.01)和成年对照组(46.9°±9.1°,P0.01)。与青年及成年对照组相比,DLS组LL、SS较小(P0.01),PT、SVA较大(P0.01);TK小于成年对照组(P0.01)。DLS组中合并退变性腰椎滑脱者37例(占35.9%),PI为53.1°±8.8°;无退变性腰椎滑脱者66例,PI为48.9°±10.6°,二者相比有统计学差异且均显著高于正常青年对照组(P0.05)。DLS组侧凸Cobb角与PT显著相关(P0.05),余冠状位参数与矢状位参数间未发现相关性;LL、PI、SS、PT两两之间显著相关(P0.01),LL、PT与TK显著相关(P0.01),SS与TK显著相关(P0.05),LL与SVA显著相关(P0.01)。结论 :DLS患者PI高于正常青年及颈椎病患者,高PI可能参与了DLS的发病机制;DLS患者退变、侧凸的腰椎仍存在调节矢状位平衡的能力。     

儿童SDSG 5/6型发育不良性腰椎滑脱患者手术治疗后骨盆平衡情况变化

目的 :探讨在儿童重度发育不良性腰椎滑脱伴不平衡型骨盆[即脊柱畸形研究学组(Spinal Deformity Study Group,SDSG)分型5和6型]患者中手术复位及重建腰骶前凸对骨盆平衡的影响。方法 :回顾性分析2015年2月～2019年2月手术治疗的23例儿童重度发育不良性腰椎滑脱患者,男2例,女21例,年龄9.6±2.4岁。均为L5滑脱,术前均伴有骨盆后倾。SDSG分型5型21例,6型2例。均行减压复位腰骶后凸矫正内固定融合术。测量术前及术后1年随访时脊柱骨盆矢状面相关参数,包括骨盆入射角(pelvic incidence,PI)、骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacral slope,SS)、L5倾斜角(L5 slope,L5S)、腰椎前凸角(lumbar lordosis,LL)、滑脱程度(slip percentage,SP)、SDSG发育不良腰骶角(SDSG dysplastic lumbosacral angle,SDSG-dys LSA)、Boxall′s滑脱角(Boxall′s slip angle,BSA)、Dubousset′s腰骶角(Dub-LSA)、腰骶后凸角(kyphotic Cobb angle,k-Cobb)。根据术后1年时骨盆旋转情况分为术后平衡型骨盆组和不平衡型骨盆组,对比两组患者后凸改善、滑脱复位率及近端固定椎的差异。结果:随访26±11个月(13～48个月),术后1年时PI无显著性改变(P0.05),SS及Dub-LSA较术前均有显著性增加(P0.05);PT、L5S、LL、SP、SDSG dys-LSA及BSA较术前均有显著性减少(P0.05);k-Cobb由术前11.6°±12.8°改善至-11.5°±16.3°(P0.05);滑脱复位率为(85.5±16.4)%。术后1年时23例患者中有5例(22%)骨盆改善为平衡型,骨盆平衡组患者滑脱复位率显著性高于不平衡组(90.9%vs. 76.2%,P0.05),两组腰骶后凸改善及近端固定椎位置无显著性差异(P0.05)。结论 :手术治疗儿童SDSG5/6型发育不良性腰骶滑脱可有效改善脊柱-骨盆矢状位序列,部分患者可从不平衡型骨盆改善为平衡型骨盆,且骨盆平衡的改善与滑脱复位相关。     

后凸型低度退变性腰椎滑脱脊柱-骨盆矢状面形态特点及临床意义

目的 :探讨退变性腰椎滑脱节段呈后凸形态对滑移参数和脊柱-骨盆矢状面形态的影响及临床意义。方法:回顾性分析2013年1月～2016年4月在我院就诊的165例Ⅰ～Ⅱ度L4/5退变性滑脱患者,其中男29例,女136例,年龄42～72岁(平均54.3±11.9岁)。根据站立位全脊柱侧位X线片滑脱节段椎间隙的形态将患者分为后凸型滑脱组和非后凸型滑脱组。测量的滑脱参数包括滑脱率、滑脱角、前/后椎间隙高度及滑脱节段滑脱率、滑脱角活动度;矢状面参数包括骨盆入射角、骨盆倾斜角、骶骨倾斜角、胸椎后凸角、腰椎前凸角、矢状面垂直距离;同时通过疼痛视觉模拟评分(visual analogue scale/score,VAS)和Oswestry功能障碍指数(Oswestry disability index,ODI)评估患者生活质量。采用独立样本t检验比较两组之间影像学和生活质量评估指标的差异。结果:21(12.7%)例为后凸型滑脱,其年龄显著高于非后凸型滑脱组(60.7±13.6 vs 53.4±11.9,P0.05)。后凸型滑脱组滑脱角明显低于非后凸型滑脱组(-3.2°±2.4°vs 7.3°±4.3°,P0.001),而滑脱率明显高于非后凸型滑脱组[(22.4±4.4)%vs (18.9±3.8)%,P0.001]。后凸型滑脱组前方椎间隙高度显著低于非后凸型滑脱组(P0.001),而后方椎间隙高度显著高于非后凸型滑脱组(P0.01)。后凸型滑脱组滑脱节段滑脱率和滑脱角活动度均显著高于非后凸型滑脱组(P0.001)。后凸型滑脱组骨盆倾斜角和矢状面垂直距离明显高于非后凸型滑脱组(P0.01),而骶骨倾斜角和腰椎前凸角明显低于非后凸型滑脱组(P0.05)。两组之间骨盆入射角和胸椎后凸角无统计学差异(P0.05),而后凸型滑脱组骨盆入射角-腰椎前凸角显著高于非后凸型滑脱组(P0.001)。后凸型滑脱组VAS腰痛、腿痛评分和ODI显著高于非后凸型滑脱组(P0.05)。结论:L4/5退变性滑脱患者中约12.7%的患者为后凸型滑脱,较非后凸型滑脱患者表现出更为明显的腰椎前凸角丢失、骨盆后旋和躯干前倾,并导致生活质量降低。     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.