连续双节段Bryan人工颈椎间盘置换术后异位骨化的长期研究

【摘要】 目的：对连续双节段Bryan人工颈椎间盘置换术后异位骨化的长期观察研究。方法：回顾性分析我科2004年1月~2011年12月行连续双节段人工颈椎间盘置换术的患者21例,其中男性15例,女性6例;年龄33~72岁,平均50.4±8.8岁。C3/4、C4/5间盘置换5例,C4/5、C5/6间盘置换14例,C5/6、C6/7间盘置换2例。随访时间96~156个月,平均随访116.5±19.6个月。记录患者术前、术后3个月及末次随访时改良日本骨科协会评分（modified Japanese Orthopaedic Association,mJOA）、视觉模拟评分法（visual analogue scale,VAS）评分,末次随访时在颈椎动力位X线片中测量人工颈椎间盘活动度,颈椎侧位X线片中测量颈椎曲度,采用McAfee分级法在颈椎侧位及动力位X线片上对人工颈椎间盘的异位骨化情况进行评估。结果：患者术前mJOA评分14.0±2.0分。术后3个月时mJOA评分15.2±1.8分,末次随访时mJOA评分16.8±1.2分,均较术前有统计学差异（P＜0.05）。术前VAS评分5.1±1.7分。术后3个月时VAS评分1.9±1.4分,末次随访时VAS评分0.9±0.8分,均较术前有统计学差异（P＜0.05）。术前颈椎曲度为平均16.7°±6.6°,末次随访时颈椎曲度为15.7°±7.3°,无统计学差异（P=0.25）。上位节段活动度为6.23°±10.13°,下位节段活动度为3.76°±4.81°,有统计学差异（P=0.025）。至末次随访时16例发生异位骨化,发生率为76.2%。根据McAfee分级,21例患者42个节段中,Ⅰ级5个节段,Ⅱ级5个节段,Ⅲ级14个节段,Ⅳ级7个节段,发生Ⅲ级以上HO的概率为50%,上位节段发生Ⅲ级和Ⅳ级HO的概率为38.0%,下位节段发生Ⅲ级和Ⅳ级HO的概率为61.9%。结论：长期随访发现行连续双节段Bryan人工颈椎间盘置换术后异位骨化发生率较高,且下位节段发生严重HO的概率明显增加。     

Bryan颈椎人工椎间盘置换术后长期疗效随访研究

目的：观察评估Bryan颈椎人工椎间盘置换术后长期疗效。 方法：本研究评估我院Bryan颈人工椎间盘置换术后患者长期临床疗效及影像学结果,采用mJOA、VAS、及NDI分别评价术前、术后1周、术后2年及末次随访临床效果并进行比较,末次随访时Odom’s分级评估临床疗效;X线侧位片及颈椎过屈过伸位片上采用Cobb法评估术前术后颈椎曲度、颈椎ROM,MRI T2加权相上根据Miyazaki分级标准评估Bryan人工椎间盘置换术后邻近节段退变,X线及CT上根据McAfee评估标准评价异位骨化（HO）发生情况。 结果：本研究共纳入患者20例,男性15例,女性5例,平均年龄43.85±3.70岁,平均随访时长88.5±16.29月,其中单节段9例,双节段11例,C3/4 2例、C4/5 9例、C5/6 15例、C6/7 5例;（1）mJOA、VAS、NDI评分术后较术前均明显改善,末次随访时Odom’s标准评级优（8例）,良（8例）,可（2例）,差（2例）;（2）FSU Cobb角、C2-7 Cobb角术前分别为2.33±4.08°、18.78±6.68°,末次随访为3.21±6.56°、15.61±6.73°,两者之间均无统计学差异（p=0.405,p=0.082）;FSU ROM术前为8.94±3.19°,术后早期及末次随访分别为9.47±3.81°、9.34±4.13°,术前术后比较均无统计学差异（p>0.05）,而C2-C7 ROM、上下邻近节段ROM术后均下降（p<0.05）;HO发生率为74.2%,其中严重HO（Ⅲ级或Ⅳ级）发生率为22.6%;末次随访时ASD发生率为46.5%,无症状性ASD发生。 结论：Bryan颈人工椎间盘置换术治疗颈椎退变性疾病可以取得持久稳定的临床效果,尽管异位骨化发生率较高,但大部分保留手术节段活动,同时邻近节段仍可见退变,但均无临床症状。     

Bryan颈椎人工椎间盘置换术后10年随访结果

目的 :观察Bryan颈椎人工椎间盘置换术后10年随访结果和并发症。方法:纳入在我院骨科行Bryan颈椎人工椎间盘置换术且获得长期随访、临床和影像学资料均完整的60例患者,其中神经根型颈椎病15例,脊髓型颈椎病41例,混合型颈椎病(脊髓型+神经根型)4例。47例患者为单节段置换,12例为双节段置换,1例为3节段置换。随访时间为124.0±8.3个月(117～150个月)。采用mJOA评分和VAS评分分别评估脊髓型颈椎病和神经根型颈椎病临床疗效,分析二次手术的原因和二次手术方案;颈椎屈伸位X线片评估末次随访时节段活动度情况,采用McAfee异位骨化分级观察末次随访时异位骨化情况。结果:脊髓型颈椎病患者术前mJOA评分为13.4±2.2分,末次随访时为15.8±1.1分(P0.05)。神经根型颈椎病患者术前上肢VAS评分为5.7±2.2分,末次随访时为0.7±0.9分(P0.05);术前颈痛VAS评分为4.7±2.2分,末次随访时为1.0±1.0分(P0.05)。混合型颈椎病患者术前m JOA评分为13.3±3.6分,末次随访时为15.4±1.1分;术前上肢VAS评分为4.3±2.6分,末次随访时为1.0±1.4分;术前颈痛VAS评分为2.8±1.5分,末次随访时为2.5±1.9分。7例患者接受了二次手术治疗,其中6例为手术节段异位骨化(包括初次手术单节段椎间盘置换术5例,双节段置换术1例;二次手术时3个节段异位骨化分级为Ⅲ级,4个节段为Ⅳ级)导致的新症状而行手术节段二次手术,1例为邻椎病行后路单开门椎管扩大成形术。74个手术节段的术前活动度为7.0°±2.9°,末次随访时活动度为4.6°±4.1°(P0.05)。末次随访时74个手术节段中有53个节段出现异位骨化,根据Mc Afee异位骨化分级,其中5个节段为Ⅱ级,21个节段为Ⅲ级,27个节段为Ⅳ级。结论:Bryan颈椎人工椎间盘置换术后随访10年取得了较好的疗效,但异位骨化的发生率较高,降低了手术节段的活动度,严重的异位骨化会导致手术节段出现新的神经症状而被迫行二次手术。     

Bryan颈椎人工椎间盘置换术的长期疗效观察

目的 评估Bryan颈椎人工椎间盘置换术的长期疗效。方法 对2004年12月至2008年8月于我院行Bryan颈椎人工椎间盘置换术的20例病人进行回顾性分析,男15例,女5例,平均年龄为（43.85±3.70）岁,其中单节段9例,双节段11例,C_3/4 2例、C_4/5 9例、C_5/6 15例、C_6/7 5例。①收集并比较其术前、术后1周、术后2年及末次随访的改良日本骨科协会（modified Japanese Orthopaedic Association, mJOA）评估治疗分数、疼痛视觉模拟量表（visual analogue scale, VAS）评分、颈椎功能障碍指数（neck disability index, NDI）以及Odom''s分级。②通过其术前、术后早期及末次随访时的X线侧位片及颈椎过屈过伸位片,评估其颈椎曲度、颈椎活动度（ROM）。③MRI T2加权像上根据Miyazaki分级标准评估Bryan人工椎间盘置换术后邻近节段的退变情况。④通过X线片及CT片根据McAfee标准评价异位骨化的发生情况。结果 ①术前及末次随访时的mJOA评分分别为（13.30±2.83）分、（15.25±2.07）分,VAS评分分别为（4.10±3.81）分、（1.55±1.53）分,NDI分别为（11.45±9.52）分、（6.00±4.78）分,所有评价指标末次随访时较术前均有显著改善,差异均有统计学意义（P均＜0.05）。末次随访时Odom''s分级为优8例,良8例,可2例,差2例。②脊柱功能单位（FSU）曲度及C₂~C₇曲度：术前分别为2.33°±4.08°、18.78°±6.68°,术后早期为4.12°±6.43°、20.00°±9.98°,末次随访时分别为3.21°±6.56°、15.61°±6.73°。FSU ROM及C₂~C₇ ROM：术前分别为9.15°±2.80°、47.28°±9.75°,术后早期为9.27°±3.83°、40.81°±14.66°,末次随访分别为9.37°±3.97°、42.03°±10.97°。3个时间点的FSU曲度及FSU ROM比较,差异均无统计学意义（P均＞0.05）,但C₂~C_{7 ROM术后较术前明显减少,与邻近节段ROM变化趋势一致。末次随访时,43个邻近节段中46.5%发生邻近节段退变（adjacent segment degeneration, ASD）,以C5/6最为常见,但均无临床表现;末次随访时31个手术节段中有23例（74.2%）发生异位骨化,其中严重异位骨化（Ⅲ、Ⅳ级）发生率为22.6%,C5/6最为常见。结论 Bryan颈椎人工椎间盘置换术治疗颈椎退变性疾病可以取得持久稳定的临床效果,尽管异位骨化发生率较高,但大部分保留手术节段活动,同时邻近节段仍可见退变,但均无临床症状。}     

人工颈椎间盘置换术治疗颈椎病的中长期临床疗效

【摘要】 目的：回顾性分析人工颈椎间盘置换术（artificial cervical disc replacement，ACDR）治疗颈椎病的中长期临床疗效及并发症发生情况。方法：2009年5月～2015年5月在我科接受ACDR治疗的68例颈椎病患者纳入本研究。其中男性32例，女性36例；年龄39.1±6.2岁（23～55岁）。脊髓型颈椎病42例，神经根型颈椎病19例，混合型颈椎病7例。术前病程9.5~21.5个月（14.5±6.3个月）。52例接受单节段ACDR，16例接受两节段ACDR。人工椎间盘为Discover假体。采用日本矫形外科学会（Japan Orthopedic Association，JOA）评分法、疼痛视觉模拟评分法（visual analogue scale/score，VAS）和颈椎功能障碍指数（neck disability index，NDI）对患者的神经功能和临床症状情况进行评估；术前、术后及末次随访时采用颈椎X线片评估患者颈椎曲度（C2-C7 Cobb角），采用颈椎过屈过伸位X线片测量手术节段的活动度，在侧位X线片上观察手术节段的邻近节段骨赘形成情况，采用骨赘形成分级判断邻近节段的退变情况。末次随访时采用颈椎CT平扫+三维重建和McAfee分级法评估手术节段异位骨化（heterotopic ossification，HO）情况。记录患者术后轴性症状等并发症发生情况。结果：随访78~132个月（98.3±17.2个月），随访期间JOA评分、VAS评分和NDI均获得了良好改善，末次随访时与术前比较均有显著性差异（P＜0.05）。术后第二天，纳入患者的颈椎曲度与术前比较有统计学差异（12.5°±3.9° vs 9.3°±5.5°, P=0.044），末次随访时的颈椎曲度与术前比较无统计学差异（10.3°±4.2° vs 9.3°±5.5°，P=0.181）。手术节段的活动度术前为6.5°±3.4°，术后第2天为8.7°±2.8°（P=0.001），术后1年随访时为8.2°±3.8°，术后2年随访时为7.5°±4.1°，术后5年随访时为5.3°±4.8°，末次随访时为4.5°±2.7°，末次随访时与术前和术后1年时比较均明显降低（P=0.021，P=0.019）。末次随访时头侧和尾侧相邻节段骨赘形成分级分别加重0.46和0.41级。术后1年随访时轴性症状发生率为4.41%（单节段组2例、两节段组1例），术后5年以后随访无颈部疼痛等主诉。末次随访时有46例（67.65%）患者、51个（60.71%）手术节段发生不同程度的HO，两节段组患者HO的发生率明显高于单节段组患者（81.25% vs 63.46%，P=0.048）。结论：ACDR治疗颈椎病具有较好的中长期临床疗效，但伴随随访时间延长HO发生率趋于增加，且并未明显获得防止邻近节段退变的优势。     

ProDisc-C人工颈椎间盘置换术后中长期随访病例的异位骨化情况分析

【摘要】目的：观察ProDisc-C人工颈椎间盘置换术后中长期影像学随访结果。方法：2006年6月～2008年11月我院骨科行单节段ProDisc-C人工颈椎间盘置换术治疗患者中,36例患者获得中长期随访,男22例,女14例,平均年龄44.7±8.1岁（27~62岁）。所有患者过伸过屈位X线片上采用McAfee分级评估假体置换节段异位骨化发生情况和异位骨化位置,采用White方法测量术前和末次随访的置换节段活动度,侧位X线片上采用Kellgren-Lawrence分级评估手术节段术前退变情况,分析其与末次随访时异位骨化的关系。结果：平均随访时间为108.6±27.0个月。36个手术节段术前活动度为9.0°±3.6°,末次随访时活动度为6.4°±3.2°,较术前明显降低（P＜0.05）。36个手术节段中有25个（69.4%）节段出现异位骨化,根据McAfee异位骨化分级,其中Ⅰ级异位骨化1个节段,Ⅱ级6个节段,Ⅲ级14个节段,Ⅳ级4个节段。出现异位骨化的25个节段中,异位骨化主要位于假体后方者11例,异位骨化主要位于假体前方者14例。手术节段术前退变Kellgren-Lawrence分级与异位骨化无明显相关性（P＞0.05）。结论：ProDisc-C人工颈椎间盘置换术后中长期随访异位骨化发生率高,降低了置换节段的活动度。     

Bryan颈椎人工椎间盘置换术后5年随访结果

目的:观察Bryan颈椎人工椎间盘置换术后5年随访结果。方法:我院从2003年12月开展Bryan颈椎人工椎间盘置换术,术后达到5年的患者共70例,其中57例获得57～69个月(平均60个月)随访。单节段置换47例,双节段置换9例,3节段置换1例。C3/4 5例、C4/5 10例、C5/6 45例、C6/7 8例。术前和末次随访时进行mJOA、VAS、NDI评分,末次随访时进行Odom′s分级评估临床疗效;术前和末次随访时,在过伸过屈侧位X线片上测量置换节段活动度,在侧位X线片上采用McAfee异位骨化分级方法评定异位骨化情况,在MRIT2加权像上采用Miyazaki颈椎间盘退变分级方法评定相邻节段椎间盘退变情况,在MRI中矢状位T2加权像上测量相邻节段突出椎间盘对椎管的侵占率。结果:(1)mJOA评分术前为13.4±1.9分,末次随访时16.1±1.1分,平均改善率为75.0%;上肢痛VAS评分术前为3.3±1.9分,末次随访时0.9±1.2分;颈肩痛VAS评分术前为3.0±1.5分,末次随访时1.6±1.4分;NDI评分术前为14.8±8.6分,末次随访时5.7±4.2分;以上指标末次随访时与术前比较均有统计学差异(P<0.05)。末次随访时Odom′s分级优21例,良27例,可7例,差2例。(2)28例患者获得X线随访,术前置换节段活动度为6.9°±3.0°,末次随访时为7.2°±3.7°,无统计学差异(P>0.05);末次随访时,30个手术节段中12个(40%)出现异位骨化,其中3个(10%)节段丧失活动度。(3)25例患者获得MRI随访,末次随访时50个相邻节段中7个(14%)椎间盘退变分级加重1级,但无相关临床症状出现;相邻节段突出椎间盘对椎管侵占率的年度平均增幅为0.3%～0.5%。结论:Bryan颈椎人工椎间盘置换术后平均5年随访的临床和影像学结果满意,手术节段活动度得到较好保留,相邻节段退变发生率较低,无相邻节段疾病发生。     

相邻双节段颈椎人工椎间盘置换术疗效的初步观察

目的:探讨相邻双节段颈椎人工椎间盘置换术后颈椎曲度及临床功能的变化.方法:2004年4月-2007年1月收治因颈椎病行相邻双节段颈椎人工椎间盘置换术患者23例,其中使用Bryan人工椎间盘17例,术前颈椎曲度不良12例:使用Prodisc-C人工椎间盘6例,术前颈椎曲I度不良4例.统计并分析患者术前和术后3、12及24个月时颈椎运动范围、颈椎中立位曲度、手术节段Cobb角、手术节段是否发生异位骨化、手术邻近节段是否发生退变、术后Odom评分、JOA脊髓功能评分及颈肩痛VAS评分.结果:术后3、12及24个月时患者的颈椎活动范围、颈椎中立位曲度、手术节段Cobb角与术前比较无显著性差异(P＞0.05).术前颈椎曲度不良的患者使用Bryan人工椎间盘置换后局部后凸加重(P＜0.05);而使用Prodisc-C者得到改善(P＜0.05).所有患者的Odom、JOA和VAS评分较术前改善明显(P＜0.05).2例患者术后出现手术节段的异位骨化,1例出现邻近节段椎间盘退变.结论:相邻双节段颈椎人工间盘置换术基本保留了颈椎的曲度和运动功能,Prodisc-C颈椎人工椎间盘对曲度不良患者有一定的矫正作用.     

颈椎前路Hybrid术式治疗相邻双节段颈椎病的中长期疗效分析

【摘要】 目的：观察颈椎前路Hybrid术式治疗相邻双节段颈椎病的中长期临床疗效、影像结果及Bryan人工颈椎间盘置换节段的在体运动功能状态。方法：回顾性分析2010年7月～2013年12月于我院行颈椎前路相邻双节段Hybrid手术的患者,置换节段采用Bryan人工颈椎间盘,融合节段采用MC+椎间融合器,纳入末次随访时置换节段活动度（range of motion,ROM）＞5°的43例患者,其中男性23例、女性20例,年龄49.1±5.6岁。脊髓型颈椎病26例,神经根型颈椎病6例,混合型颈椎病11例。术后随访84~119个月（95.43±8.21个月）,采用日本骨科协会（Japanese Orthopaedic Association,JOA）颈椎评分、颈椎功能障碍指数（neck disability index,NDI）、疼痛视觉模拟评分（visual analogue scale,VAS）及Odom分级评估临床疗效。收集术前与末次随访时的颈椎中立侧位和动力位X线片,对比术前与末次随访时的颈椎整体ROM及曲度（C2-C7）、手术节段曲度、置换节段屈伸旋转中心（flexion and extension-center of rotation,FE-COR）及ROM、手术相邻节段ROM;末次随访时,观察邻近节段退变（adjacent segment degeneration,ASD）发生情况、融合节段融合情况,测量置换节段平移距离与关节突关节解剖参数：上关节突高度（height of superior articular process,HSAP）、关节突关节间隙倾斜度（orientation of zygapophyseal joint spaces,OZJS）和上关节突关节面长度（length of superior articular surface,LSAS）,分析置换节段FE-COR与各项随访指标的相关性。结果：末次随访时,JOA评分较术前显著性升高（9.26±3.38 vs 15.21±1.42,P＜0.05）,改善率为（80.23±13.80）%,NDI、颈痛VAS评分及双上肢痛VAS评分均较术前显著性降低（34.12±8.96 vs 7.21±4.32,P＜0.05;5.77±2.28 vs 1.72±0.96,P＜0.05;5.26±2.67 vs 1.14±0.83,P＜0.05）,改善率分别为（80.03±10.52）%、（69.85±13.44）%和（78.84±15.89）%。Odom分级优24例、良12例、可7例,优良率为83.72%。颈椎整体曲度、手术节段曲度分别由术前的14.76°±8.04°、4.78°±5.86°增加至末次随访的20.62°±9.06°、6.75°±4.65°（P＜0.05）,颈椎整体ROM、置换节段FE-COR及ROM、手术相邻节段ROM与术前比较均无统计学差异（P＞0.05）。81个纳入研究的手术相邻节段（上位43个、下位38个）7个节段发生ASD（8.64%）,分属于7例患者（7/43,16.28%）,1例患者融合节段未获得骨性融合,但处于稳定状态（ROM＜2°）,其余患者融合节段均获得骨性融合,未发现与FE-COR横坐标（X）相关的随访指标（|r|＜0.5或P＞0.05）,FE-COR纵坐标（Y）与同节段ROM、平移距离呈负相关（r=-0.674,P＜0.05;r=-0.792,P＜0.05）,与HSAP呈正相关（r=0.754,P＜0.05）,与其他随访指标无显著相关性（|r|＜0.5或P＞0.05）。结论：颈椎前路相邻双节段Hybrid手术患者7年以上随访的临床与影像学结果满意,无证据显示融合节段对置换节段运动功能状态产生明显影响。     

单节段人工颈椎间盘置换术后小关节退变的长期临床研究

【摘要】 目的：分析人工颈椎间盘置换（artificial cervical disc replacement，ACDR）术后颈椎小关节退变的危险因素，评价其对颈椎节段运动和临床疗效的影响。方法：回顾性分析我科2003年1月~2008年1月行单节段Bryan人工颈椎间盘ACDR术的颈椎退行性疾病患者70例，其中男性43例，女性27例；术后随访时间129±14（105~165）个月；年龄55.7±8.4（37~76）岁。术前、术后及末次随访时通过颈椎动力位X线片测量手术节段活动度和颈椎整体活动度；术前、末次随访时通过CT影像根据颈椎小关节定量评分系统评估颈椎小关节退变程度。术前及末次随访同时进行日本骨科协会（Japanese Orthopaedic Association，JOA）评分及颈椎功能障碍指数量表（neck disability index，NDI）评估患者临床症状，在末次随访时进行Odom标准评价分级和颈痛的视觉模拟评分（visual analogue scale，VAS）。结果：术前小关节无或轻度退变患者41例，中度退变患者28例，重度退变患者1例；末次随访时，小关节轻度退变患者16例，中度患者退变35例，重度关节退变患者19例。通过斯皮尔曼双变量相关性检验发现小关节退变与性别、年龄有相关性。高龄、男性是小关节退变增加的危险因素，手术节段与小关节退变程度无相关性。患者术前和末次随访时手术节段活动度不存在统计学差异（9.7°±4.5° vs 8.7°±5.4°，P>0.05），术前和末次随访时颈椎整体活动度不存在统计学差异（46.5°±15.2° vs 46.1°±13.0°，P>0.05）。患者术前及末次随访时小关节退变评分具有统计学差异（1.5±0.8分 vs 2.6±1.2分，P<0.05）；术前与末次随访时JOA评分具有统计学差异（13.5±1.9分 vs 16.5±1.4分，P<0.05）；术前与末次随访时NDI存在统计学差异（0.27±0.08 vs 0.16±0.10，P<0.05）。末次随访时Odom分级为优秀的有35例患者，为良好的有29例，为尚可的有6例，没有分级为差的患者，末次随访时VAS评分为3.47±1.55分。ACDR术后末次随访小关节退变程度与手术节段活动度呈负相关（r=-0.392，P=0.001），与整体活动度也呈负相关（r=-0.388，P=0.001），与JOA评分、NDI、Odom分级、VAS评分无显著性相关（P>0.05）。结论：高龄和男性是ACDR术后小关节退变的危险因素，小关节的退变程度与患者术后的颈椎活动度存在负相关，小关节退变程度与临床症状的缓解程度无关。     

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.