3D打印个体化导板与机器人辅助在成人退变性脊柱侧凸椎弓根螺钉置钉中的应用比较

【摘要】 目的：比较3D打印个体化导板与机器人辅助置钉在成人退变性脊柱侧凸（adult degenerative scoliosis,ADS）矫形手术中的应用效果。方法：对2020年1月~2022 年12月在本科室住院接受矫形手术治疗的18例ADS患者进行回顾性分析,其中男性3例,女性15例,年龄46~73岁,平均63.2±8.2岁。共置入椎弓根螺钉236枚,根据辅助置钉方式分为两组,3D打印个体化导板组（3D打印组,11例,置入142枚椎弓根螺钉）和机器人辅助组（机器人组,7例,置入94枚椎弓根螺钉）。术后均进行至少6个月随访。术前测量并比较顶椎旋转角、侧凸Cobb角;术后1周采用Gertzbein-Robbins分类标准对所有椎弓根螺钉进行判断分类,对比两组患者螺钉置入的准确性和满意度;分析比较两组患者的手术时间和并发症发生率。结果：3D打印组年龄（63.6±9.0岁）、性别（男/女：2/9）、平均置钉数量（12.91±3.83枚）、侧凸Cobb角（40.36°±11.82°）、顶椎旋转角（30.27°±7.25°）分别与机器人组[年龄（62.6±7.3岁）、性别（男/女：1/6）、平均置钉数量（13.43±3.60枚）、侧凸Cobb角（38.14°±12.84°）、顶椎旋转角（29.86°±9.65°）]比较,均无统计学意义（P>0.05）。机器人组较3D打印组手术时间长（354.29±53.73min vs. 282.27±73.87min）,差异有统计学意义（P<0.05）。置钉结果统计,3D打印组共置入142枚椎弓根螺钉,其中A类128枚,B类10枚,C类4枚;机器人组共置入椎弓根螺钉94枚,其中A类86枚,B类5枚,C类3枚;两组患者均未出现D、E两类;3D打印组置钉准确率（90.14%）及满意度（97.18%）,分别与机器人组置钉准确率（91.49%）及满意度（96.81%）比较均无统计学差异（P>0.05）。并发症发生率,3D打印组（36.36%）与机器人组（57.14%）比较无显著差异（P>0.05）。结论：两种辅助置钉方式均可以协助脊柱外科医师进行ADS患者的精准置钉,但3D打印个体化导板置钉用时更短。     

机器人辅助皮质骨轨迹螺钉内固定术治疗腰椎退行性疾病的置钉准确率及学习曲线分析

【摘要】 目的：评估骨科机器人辅助皮质骨轨迹（cortical bone trajectory,CBT）螺钉内固定技术在腰椎退行性疾病中应用的置钉准确率、皮质接触情况以及该技术的学习曲线。方法：回顾性分析2019年10月~2021年4月应用“天玑”骨科手术机器人辅助置入CBT螺钉治疗45例L4-5退行性疾病患者的资料,其中男性27例,女性18例,年龄64.3±6.9岁,腰椎间盘突出症8例,腰椎管狭窄症28例,退变性腰椎滑脱症9例。按患者接受手术日期先后顺序平均分为A、B、C三组,每组15例。统计手术时间、出血量,术前及术后6个月时进行VAS和JOA评分,采用ln曲线回归分析方法分析手术时间随手术例数变化的趋势,术后通过CT评估置钉准确率及皮质接触层数,随访期间通过X线片及CT观察螺钉松动、椎间融合、融合器沉降及移位情况。结果：患者均顺利完成手术,手术时间140~195min（163.5±11.3min）,出血量140~265ml（210.0±28.9ml）。共置入166枚螺钉,螺钉可接受率为97%（161/166）,平均总皮质骨接触层数为4.9±0.6层,平均椎弓根皮质骨接触层数为3.3±0.6层。B、C组手术时间及出血量较A组减少,差异有统计学意义（P＜0.05）,B、C组之间无统计学差异（P＞0.05）。手术时间（y）随着手术例数（x）的增加而减少[y=-10.243ln（x）±192.89,R2=0.637,P＜0.001],并在B、C组达到相对稳定。三组置钉准确率、皮质接触层数无统计学差异（P＞0.05）。术后6个月时腰痛VAS评分由术前4.8±0.7分降至1.9±0.6分（P＜0.001）,腿痛VAS评分由术前7.5±0.7分降至1.8±0.6分（P＜0.001）,JOA评分由术前11.3±1.8分升至23.3±1.6分（P＜0.001）。随访期间41例发生融合,1例融合器移位,未出现螺钉松动和融合器沉降。结论：机器人辅助下CBT螺钉内固定术治疗腰椎退行性疾病置钉准确率高,确保螺钉与皮质之间充分接触,安全性高。随着手术例数的增加其手术时间以及出血量逐渐减少,并在15台后趋于稳定。     

3D打印体外导板辅助经皮椎弓根螺钉固定术治疗胸腰椎骨折的临床疗效观察

【摘要】 目的：观察3D打印体外导板辅助经皮椎弓根螺钉固定术治疗胸腰椎骨折的临床疗效。方法：回顾性分析2017年8月~2020年8月行经皮椎弓根螺钉固定手术的47例胸腰椎骨折患者的临床资料,男13例,女34例;年龄21~69岁。均为单节段损伤,T12 11例,L1 26例,L2 7例,L3 2例,L4 1例。22例术前制作3D打印个体化体外导板,模拟置钉,术中辅助置钉（导板组）;25例采用X线透视辅助下徒手置钉（徒手组）。对比两组手术时间、置钉时间、术中X线透视次数、术中出血量、术后并发症;采用Neo分级标准评价两组手术置钉等级,计算置钉准确率;在术前、术后X线片上测量骨折椎体前缘高度和Cobb角,计算椎体矢状面指数,评价骨折复位及矫正情况;术前和术后1d、7d及1年时进行疼痛视觉模拟评分（visual analogue scale,VAS）评分、日本骨科协会（Japanese Orthopedics Association,JOA）评分和Oswestry功能障碍指数（Oswestry disability index,ODI）评定。结果：导板组手术时间、置钉时间、术中X线透视次数、术中出血量分别为63.57±12.18min、23.69±3.63min、15.26±4.15次、48.82±13.72ml;徒手组分别为85.56±16.27min、41.36±8.12min、26.93±6.93次和74.35±18.64ml;导板组均少于徒手组,差异有统计学意义（P<0.05）。导板组0级置钉119枚,1级置钉3枚,置钉准确率为97.54%;徒手组0级置钉128枚,1级置钉10枚,2级置钉1枚,置钉准确率为92.09%,导板组置钉准确率高于徒手组,差异有统计学意义（P<0.05）。术后两组的椎体前缘高度、椎体矢状面指数和Cobb角与术前相比均有显著性改善（P＜0.05）;两组同时间点比较均无统计学差异（P＞0.05）。两组术后VAS评分、JOA评分和ODI与术前比较均有显著性改善,差异有统计学意义（P<0.05）,两组间同时间点比较均无统计学差异（P＞0.05）。两组患者术后伤椎均达到骨性愈合,均未出现术后并发症。结论：3D打印体外导板辅助经皮椎弓根螺钉固定术治疗单节段胸腰椎骨折可取得良好效果,与徒手经皮椎弓根螺钉固定术相比能够显著性提高置钉准确率,并缩短手术时间、减少术中辐射暴露。     

引导通道辅助下经皮椎弓根置钉与传统经皮椎弓根置钉的比较

目的 :比较引导通道辅助下经皮椎弓根置钉与传统透视下经皮椎弓根置钉的手术时间、射线暴露时间和置钉准确性。方法:70例无神经症状的胸腰椎骨折患者,随机分为A、B两组,A组35患者采用传统透视下经皮置入椎弓根螺钉,共置入180枚椎弓根螺钉;B组35例患者采用引导通道辅助下经皮置入椎弓根螺钉,共置入178枚椎弓根螺钉,均由同一术者完成置钉。记录两组椎弓根置钉时间、射线暴露时间,术后连续2次复查手术节段CT对两组病例置钉准确性进行评估并分级。比较两组患者单枚椎弓根螺钉置钉时间、射线暴露时间和置钉准确性。结果:两组患者年龄、体重指数、合并疾病、骨折类型、性别比例均无统计学差异(P0.05)。A组单枚椎弓根螺钉平均置钉时间为14.11±3.32min,B组为11.35±2.82min,两组比较差异有统计学意义(P=0.0042)。A组平均射线暴露时间为12.07±3.06s,B组为8.06±2.15s,两组比较差异有统计学意义(P=0.0031)。A组155枚(86.11%)螺钉为A级置钉,23枚螺钉(12.78%)为B级置钉,1枚螺钉(0.56%)为C级置钉,1枚螺钉(0.56%)为D级置钉;B组156枚螺钉(87.64%)为A级置钉,20枚螺钉(11.24%)为B级置钉,1枚螺钉(0.56%)为C级置钉,1枚螺钉(0.56%)为D级置钉,两组比较差异无统计学意义(P0.05)。结论 :引导通道辅助下经皮椎弓根置钉与传统经皮椎弓根置钉具有相同的准确性,但能明显减少置钉时间及辐射暴露时间。     

3D导航引导与徒手椎板关节突螺钉置钉在单节段腰椎融合手术中的应用比较

目的 比较3D导航引导与徒手椎板关节突螺钉置钉在单节段腰椎融合手术中的疗效。方法 纳入2020年1月至10月我院骨科收治的拟行单节段腰椎融合手术的病人30例,按参与研究的奇偶顺序分为两组,3D导航组15例,行3D导航引导下椎板关节突螺钉置钉,徒手置钉组15例,行徒手椎板关节突螺钉置钉。统计两组病人的术中透视次数、操作时间、术中失血量及24 h引流量,拔除引流管后统计并对比两组的置钉准确性,分别于术后第1、3、7天测量两组的红细胞沉降率（ESR）及C反应蛋白（CRP）水平,同时对比两组的日本矫形外科协会（JOA）评分改善情况及椎间融合情况。结果 两组病人均顺利完成手术,未予以输血。3D导航组的术中透视次数、手术时间、术中失血量及引流量分别为（2.43±0.25）次、（110.86±10.75） min、（150.45±23.46） mL、（83.87±10.63） mL,徒手置钉组分别为（6.52±1.21）次、（152.37±13.45） min、（213.68±34.68） mL、（156.84±15.67） mL,3D导航组各项手术指标均优于徒手置钉组（P＜0.05）;3D导航组的置钉准确性显著优于徒手置钉组（100% vs. 73.33%,P＜0.05）;术后第1、3、7天时,3D导航组的ESR、CRP均较徒手置钉组显著降低（P＜0.05）;末次随访时,3D导航组的JOA改善率为75.00%,稍高于徒手置钉组的72.41%,但两组对比,差异无统计学意义（P＞0.05）。随访期间,两组均达到良好椎间融合,无椎间融合期移位、螺钉断裂、松动或移位等情况出现。结论 3D导航引导与徒手椎板关节突螺钉置钉均可有效改善单节段腰椎融合手术病人的JOA评分,但与徒手置钉相比,3D导航引导下椎板关节突螺钉置钉可改善病人手术指标,提升置钉准确性,降低术后ESR和CRP,可作为腰椎椎板关节突螺钉置钉的优先选择方案。     

机器人辅助与徒手置钉在腰椎翻修术早期结果比较

[目的]比较Renaissance机器人系统辅助椎弓根螺钉置入与徒手椎弓根螺钉置入在腰椎翻修手术中的安全性及准确性。[方法]回顾性分析2018年1月~2018年12月在本院行腰椎后路翻修手术的病例69例,其中使用Renaissance机器人系统辅助椎弓根螺钉置入共31例,使用传统徒手椎弓根螺钉置入38例。记录临床资料,并根据术后CT对螺钉精度进行Gertzbein Robbins分级,比较螺钉置入准确性。[结果]两组患者手术时间、术后出血量及手术相关并发症等差异无统计学意义(P0.05)。机器人组术中出血量、术中透视次数显著少于徒手组(P0.05)。机器人辅助组共置入螺钉152枚,术后CT评估显示:A级置钉137枚,B级置钉11枚,C级置钉4枚,没有D、E级置钉,置钉准确率97.37%。徒手组共置入螺钉194枚,术后CT评估显示:A级置钉129枚,B级置钉48枚,C级置钉15枚,D级置钉2枚,没有发现E级置钉,置钉准确率91.24%。在螺钉精度分级及螺钉准确性方面,机器人组优于徒手组,差异具有统计学意义(P0.05)。[结论]与徒手置钉技术相比,Renaissance机器人系统辅助椎弓根螺钉置入在腰椎翻修手术中具有置钉精度高、且术中出血及术中透视次数少的优势。     

保留小关节囊的改良椎弓根螺钉固定技术在腰椎外科手术中的应用

【摘要】 目的：与传统后正中入路腰椎椎弓根螺钉内固定对比,研究一种减少剥离范围、保留小关节囊置入腰椎椎弓根螺钉的技术,以减少腰椎后正中入路椎弓根螺钉内固定的手术损伤。方法：对2008年3月～2011年12月收治的需行单节段腰椎间盘切除、椎板减压及椎间植骨融合经椎弓根螺钉内固定手术治疗的210例患者,根据患者的手术当日日期为单双号,将患者分为A组和B组,A组采用传统后正中入路（自正中口剥离至双侧小关节外侧）行腰椎减压融合手术（PLIF）100例,B组采用新技术（自正中切口剥离至小关节突内缘,保护小关节囊）行腰椎减压融合手术（PLIF）110例,其中A组年龄为48.4±0.7岁,男56例,女44例,B组年龄为47.3±0.9岁,男63例,女47例。比较两组的手术时间、术中出血量、术后引流量及置钉准确率。结果：手术均顺利完成,手术时间A组为143±12min,B组为120±13min,B组明显少于A组（P<0.05）;术中出血量A组为280±10ml,B组为170±7.5ml,B组明显少于A组（P<0.05）;术后引流量A组为216±10ml,B组为125±8ml,B组明显少于A组（P<0.05）;两组间年龄、性别、置钉准确率无显著性差异（P>0.05）。经平均19个月随访,A组融合率96.0％,B组融合率93.6％,两组间差异无显著性（P＞0.05）。结论：与传统后正中入路腰椎椎弓根螺钉内固定相比,保留小关节囊的改良腰椎椎弓根螺钉内固定技术是一种新的微创手术技术,具有创伤小、对椎旁组织损伤小、手术时间短、出血量少、引流量少的优点。     

3D打印导航模板与计算机导航辅助置入C_2椎弓根和侧块螺钉的对比研究

目的比较3D打印导航模板辅助C_2椎弓根和侧块螺钉置钉与计算机导航辅助置钉准确性和安全性的差异,探讨3D打印导板在C_2螺钉置钉中的应用价值。方法纳入我院采用C_2椎弓根螺钉和C_2侧块螺钉后路内固定患者64例,根据辅助螺钉置入方法的不同分为3D打印导航模板置钉组(A组)和计算机导航置钉组(B组),其中A组又分A1(导板置入C_2椎弓根螺钉)、A2(导板置入C_2侧块螺钉)两个亚组;B组又分B1(导航置入C_2椎弓根螺钉)、B2(导航置入C_2侧块螺钉)两个亚组。A组:纳入我院2015年6月至2018年9月采用3D打印导板置钉患者32例,其中男21例,女11例;年龄27～64岁,平均(47.2±11.1)岁。B组:纳入我院2014年1月至2018年9月采用计算机导航置钉患者32例,其中男19例,女13例;年龄25～60岁,平均(45.6±10.4)岁。所有患者术前均行颈椎X线、CT、MRI及CTA。记录并比较两组患者疾病类型、置钉时间、术中出血量、术中透视次数、术前、术后3 d、术后6个月的VAS评分及JOA评分。所有患者术后均行颈椎CT平扫,按照Hlubek等提出的新的C_2螺钉分级标准、根据CT结果分别记录并比较两组的置钉准确率及相关并发症的发生率。结果两组中A组置钉时间、术中透视次数均优于B组,差异有统计学意义(P0.05),术中出血量比较差异无统计学意义(P0.05)。两组术前视觉模拟评分(visual analogue scale,VAS)和日本矫形外科协会(Japanese orthopedic association,JOA)评分差异无统计学意义(P0.05),术后3 d及术后6个月两组的VAS评分和JOA评分较术前均明显改善,差异有统计学意义(P0.05),组间比较差异无统计学意义(P0.05)。两组中A组共置入C_2螺钉64枚,A级置钉精确率为95.31%,其中A1组共置入52枚,A级置钉精确率为96.15%;A2组共置入12枚,A级置钉精确率为91.67%。B组共置入C_2螺钉64枚,A级置钉精确率为84.38%,其中B1组共置入50枚,A级置钉精确率为84.00%;B2组共置入14枚,A级置钉精确率为85.71%。A组与B组置钉准确率差异有统计学意义(P=0.041),A1组与B1组置钉精确率差异有统计学意义(P=0.039);A2组与B2组置钉精确率差异无统计学意义(P=0.636)。两组均无置钉相关的血管、神经并发症发生。结论虽然3D打印导航模板与计算机导航辅助置入C_2椎弓根、侧块螺钉均能提供较高的准确性、安全性和临床疗效,但导板技术在C_2椎弓根螺钉置入准确率方面更优于导航技术。     

不同手术次序全内镜下腰椎融合术治疗腰椎退变性疾病的疗效比较

【摘要】 目的：比较不同手术次序全内镜下腰椎融合术治疗腰椎退变性疾病的临床效果。方法：回顾性分析2019年10月~2021年10月在我院行全内镜下腰椎融合术治疗的64例腰椎退变性疾病患者的资料,男29例,女35例,年龄40~79岁（59.7±13.5岁）;病程1~10年（3.1±1.6年）,体质量指数（body mass index,BMI）10~31kg/m2（25.3±3.1kg/m2）;退变性腰椎滑脱伴椎管狭窄20例,腰椎间盘突出伴退变性椎管狭窄21例,退变性椎管狭窄伴腰椎不稳18例,退变性侧凸伴椎管狭窄5例;单节段病变59例,双节段病变5例。其中38例采用C型臂X线机辅助下定位标记-置入导丝-内镜下减压植骨融合-经皮置钉的手术顺序（A组）;26例采用C型臂X线机辅助下定位标记-内镜下减压植骨融合-置入导丝-经皮置钉的手术顺序（B组）。两组患者的年龄、性别、BMI、病程和病变节段均无显著性差异（P>0.05）。比较两组的围手术期指标（手术时间、术中透视次数、术中出血量、术后引流量、术后卧床时间、住院时间、并发症）,按Gertzbein-Robbins等的标准评估椎弓根螺钉置入的准确性,术前和术后1年时随访的腰腿痛视觉模拟评分（visual analogue scale,VAS）、Oswestry功能障碍指数（Oswestry disability index,ODI）和腰椎前凸角、椎间隙高度、手术节段前凸角,观察术后1年时的椎间融合情况。结果：两组患者均顺利完成手术,两组手术时间、术中透视次数有统计学差异（A组189.6±35.4min、13.1±3.5次,B组210.4±33.5min、15.9±5.4次,P＜0.05）;术中出血量、术后引流量、术后卧床时间、住院时间和并发症发生率均无统计学差异（A组57.5±16.3ml、110.8±55.0ml、2.0±1.2d、7.3±1.2d和7.89%;B组60.4±18.8ml、119.8±49.0ml、2.2±0.9d、7.4±2.2d和19.23%）（P>0.05）。A组置钉优良率（91.8%）优于B组（77.8％）（P＜0.05）。两组术后1年时的VAS评分（A组1.9±1.0分,B组1.8±1.0分）、ODI[A组（27.6±7.2）%,B组（26.8±6.7）%]与术前VAS评分（A组6.7±1.5分,B组6.4±1.6分）、ODI[A组（72.4±11.2.2）%,B组（73.5±13.6）%]比较均有显著性改善（P＜0.05）,两组同时间点比较比较均无显著性差异（P>0.05）。两组术后1年的腰椎前凸角、椎间隙高度、手术节段前凸角（A组36.2°±6.5°、15.8±2.4mm、11.4°±1.4°;B组32.9°±6.5°、15.3±2.0mm、11.2°±1.1°）与术前（A组21.6°±6.5°、12.6±2.0mm、8.5°±1.9°;B组22.2°±7.7°、12.3±2.0mm、8.0°±1.9°）比较均有显著性差异（P＜0.05）,两组同时间点比较均无显著性差异（P>0.05）。两组术后1年椎间融合率均为100％。结论：两种手术顺序全内镜下腰椎融合术治疗腰椎退变性疾病均确切可行,但采用C型臂辅助下定位标记-置入导丝-内镜下减压植骨融合-经皮置钉的顺序手术时间更短,透视次数更少,置钉优良率更高。     

改良3D打印导板辅助颈椎椎弓根螺钉置钉的准确性研究

【摘要】 目的：探讨改良3D打印导板辅助颈椎椎弓根螺钉置钉的准确性。方法：回顾性分析2016年1月~2023年1月在我院行颈椎后路椎弓根螺钉内固定手术的60例患者的临床资料,其中男30例,女30例,年龄58.7±13.8岁（17~84岁）;根据颈椎后路手术是否使用导板辅助置钉分为导板组及徒手置钉组。导板组（30例）采用改良3D打印导板辅助颈椎椎弓根置钉,徒手置钉组（30例）采用角度尺辅助颈椎弓根置钉,两组患者年龄、性别、术前诊断无统计学差异（P＞0.05）。所有患者术后1周行颈椎CT扫描,按照Kaneyama标准判断椎弓根置钉准确性：0级,螺钉完全处于椎弓根中,没有穿破骨皮质;1级,螺钉穿破皮质<螺钉直径的50％;2级,螺钉穿破皮质≥螺钉直径的50％但没完全穿出;3级,完全穿出骨皮质。记录椎弓根置钉准确率（0级+1级螺钉占比）及因螺钉误置导致的血管神经损伤、切口感染、脑脊液漏、螺钉松动断裂等并发症。结果：导板组共置入椎弓根螺钉152枚,其中0级74枚,1级68枚,2级10枚,3级0枚,置钉准确率93.4%;徒手置钉组共置入椎弓根螺钉136枚,其中0级53枚,1级61枚,2级18枚,3级4枚,置钉准确率83.8%,导板组置钉准确率高于徒手置钉组（P＜0.05）。所有患者均未出现因椎弓根螺钉误置导致的血管神经损伤、切口感染及脑脊液漏等相关并发症。所有患者随访5～29个月（14.2±7.7个月）,无内固定松动、断裂等并发症。结论：改良3D打印导板辅助颈椎椎弓根置钉可提高置钉精准度。     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.