后路椎体间融合术后融合器脱出的原因及其翻修术

目的：探讨后路椎体间融合术后融合器脱出的原因及其翻修方法。方法：10例后路椎体间融合术后融合器脱出行翻修术的病例，其中腰椎滑脱症5例，腰椎管狭窄症3例，腰椎间盘突出症2例。手术节段为L4／54例，L5／S1 3例，L4／5＋L5／S1 3例；融合器应用BAK（旋入型）7例，聚醚醚酮矩形融合器（PEEK）2例，钛金属矩形融合器1例。于首次术后1～90d内行翻修术。就其脱出原因，再次手术方法及疗效进行分析。结果：融合器脱出的原因：矩形融合器中2例型号太小，1例放置位置偏后；旋入型融合器1例定位错误，其余大都因两枚融合器之间发生碰撞挤压所致。翻修术后获得完整随访资料者8例，随访时间10-36个月，平均17个月，均得到融合，无融合器再次移位或脱出以及内同定的断裂，1例伴有足下垂者遗留患足背伸肌力减弱，其余病例神经症状消除。结论：后路腰椎椎体间融合术后融合器脱出的可能原因有融合器型号偏小导致椎间隙撑开不够，放置位置偏后，两枚融合器不对称或距离太近发生碰撞等。早期、积极的手术翻修能取得较好的疗效。     

椎弓根螺钉联合椎间植骨融合器治疗腰椎滑脱症的远期疗效分析

[目的]探讨椎弓根螺钉系统联合椎间植骨融合器治疗峡部不连性腰椎滑脱症的远期疗效。[方法]自1996年10月~2002年10月本组收治峡部不连性腰椎滑脱症105例,随访资料齐全者86例。所有患者均行椎弓根螺钉系统复位滑脱,椎间植骨融合器行椎间融合固定。62例患者中1枚融合器从后斜向前呈45°植入,24例为2枚融合器从后向前垂直植入。随访测定固定节段的椎体间有无移位、滑脱有无复发,比较术前、术后2周及随访时固定椎间隙高度与近端第2椎间隙高度比值的变化。[结果]随访2~8年,平均35个月。根据NaKai评分标准,本组优56例,良13例,可17例,优良率为80.23%。Ⅰ度腰椎滑脱19例术后全部解剖复位;Ⅱ度腰椎滑脱51例中5例遗留Ⅰ度滑脱;Ⅲ度腰椎滑脱16例中4例留有Ⅰ度滑脱。末次随访时使用1枚融合器或2枚融合器所固定的椎间隙高度与近端第2椎间隙高度的比值与术后2周时的比值相比有所减低,滑脱无复发。[结论]椎弓根螺钉加椎间植骨融合器治疗腰椎滑脱症手术疗效满意,显著提高融合率,预防神经根管狭窄、神经卡压的发生,减少术后断钉和滑脱复发等问题。     

下腰椎失稳合并椎管狭窄症的手术治疗

目的：观察下腰椎失稳合并椎管狭窄症患者经椎弓根螺钉系统及椎体融合器治疗的效果。方法：采用后路减压，椎弓根螺钉系统内固定，椎体间融合器BAK融合。结果：术后随访1年一4年3个月(平均2年4个月)，椎体间骨性融合率1年89．6％，2年2个月100％，临床症状消失满意率92％。结论：采用椎管减压、椎弓根螺钉系统加椎间融合器固定，可使滑脱失稳的椎体部分或全部复位，保证脊柱骨性融合，达到脊柱稳定、解除症状的目的。     

颈椎椎体次全切除钛网钉板系统的临床应用

目的探讨颈椎前路椎体次全切除钛网钉板植骨融合的临床效果。方法自2001年3月～2003年3月间应用颈前路椎体次全切除钛网植骨融合及钉板固定治疗颈椎管狭窄性疾病22例，其中4例患者行2椎体次全切除3节椎间隙减压手术。术后观察减压、固定、融合及神经功能恢复情况，并行X线摄片或CT扫描检查。结果患者获6～12个月随访，神经功能得到不同程度改善，无加重情况。椎间隙高度无丢失、无成角，均获得骨性融合。术后3d在颈围领固定下下床活动，4周后可恢复较轻工作。结论此术式可避免传统手术方法的缺点，即不取自体髂骨，融合率高，稳定性好，并减压彻底，疗效好，是一种值得推广的新技术。     

A simple and inexpensive metabolic cage for mice

An inexpensive and easily constructed metabolic cage for mice is presented. This apparatus can reliably monitor food and fluid consumption, as well as urine and fecal output, in a relatively non-intrusive manner.     

颈椎前路椎体间微创融合器的生物力学实验研究

目的评价植入镍钛记忆合金微创融合器(NiTi-TFC/C)的颈椎节段的稳定性及压缩力学性能。方法采集24只羊颈椎标本随机分为4组,每组6份,四组处理分别为:单取髓核组、自体髂骨植骨组、微创融合器组和钛制融合器组(InterFix)。所有标本进行前路减压,并对后3组进行椎间融合术。分别对各组标本进行生物力学测试并进行比较。结果微创融合器组与钛制融合器组在强度、刚度及扭转力学等方面无显著性差异(P>0.05)。而微创融合器组与自体髂骨植骨组具有显著性差异(P<0.05)。最大承载力为12050N。结论该微创融合器强度大、刚度高、抗扭转能力强,具有良好的抗压能力,为颈椎融合提供新型的融合装置。     

Walking modality affects respiratory muscle action and contribution to respiratory effort

We hypothesized that walking at increased speed or increasing gradient might have different effects on chest wall kinematics and respiratory muscle power components, and contribute differently to respiratory effort sensation. We measured the volumes of chest wall compartments by optoelectronic plethysmography, esophageal, gastric and transdiaphragmatic (P _di) pressures, and the sensation of the respiratory effort by a Borg scale in five normal subjects walking both at ascending gradient with constant speed (AG) and at ascending speed with constant gradient (AS). Chest wall kinematics, evaluated by displacement of chest wall compartments, did not show any significant difference between AS and AG. Muscle power, calculated as the product of mean flow and mean pressure, increased similarly, but its partitioning into pressure and velocity of shortening differed in the two modes. A greater increase in the pressure developed by the abdominal muscles (P _abm) (4.06-fold), and in the velocity of shortening of both rib cage inspiratory muscles (v _rcm,i) (2.01-fold) and the diaphragm (v _di) (1.90-fold) was associated with a lower increase in the pressure developed by the rib cage inspiratory muscles (P _rcm,i) (1.24-fold) and P _di (0.99-fold) with AG. Instead, with AS, a lower increase in P _abm (2.12-fold), v _rcm,i (1.66-fold) and v _di (1.54-fold) was associated with a greater increase in P _rcm,i (1.56-fold) and P _di (1.97-fold). A combination of P _abm and v _di during AG (Wald ²=23.19, P<0.0000), with the addition of P _rcm,i during AS (Wald ²=29.46, P<0.0000), was the best predictor of Borg score. In conclusion, the general strategy adopted by respiratory centers during different walking modes does not differ in terms of ventilation, chest wall kinematics, and respiratory muscle power production, whereas it does in terms of partitioning of power into pressure and velocity of shortening, and respiratory muscle contribution to respiratory effort sensation. Combinations of different patterns of flow and pressure generation made the respiratory effort sensation similar during AS and AG modes.     

Tissue cages for study of experimental streptococcal infection in rabbits. II. Humoral and cell-mediated immune response to erythrogenic toxins

Infection of rabbits with erythrogenic toxin producing streptococcal strains caused a marked increase of humoral antibodies, which was detected by immunoprecipitation and ELISA. An antibody response directed towards the erythrogenic toxin type A was demonstrated by fused rocket immunoelectrophoresis. All toxinogenic reference strains produced ET type A under in vivo conditions despite that this toxin was not always demonstrated under in vitro conditions. The infection resulted in an increase of mitogenic response of peripheral lymphocytes to the initial nonspecific mitogenic erythrogenic toxins, whereas the Con A stimulation was depressed starting 14 days after infection and lasting during a period of 90 days. Since a normal antibody response was evoked, it seems likely that the T helper cell function was not affected.     

Tissue cages for study of experimental streptococcal infection in rabbits. I. Production of erythrogenic toxins in vivo

Tissue cages implanted subcutaneously were used to infect rabbits with erythrogenic toxin (ET) producing streptococci. The in-vivo production of ET was followed during the infection by immunoprecipitation analyses of the tissue cage fluid (TCF). ET types A and C were mainly detected during the first week of infection, but, as late as 4 weeks after the inoculation, ET was occasionally found in TCF. The nonspecific mitogenic activity of ET on human lymphocytes was also used as a biological marker to recognize ET in TCF. Mitogenic activity was detected in 90% of samples during the first week. In order to characterize the mitogenic material released by growing streptococci, TCF was electrofocused in polyacrylamide gel. The eluates of sliced gels were checked for mitogenic activity and compared with a purified ET preparation containing ET types A and C. It could be verified that ET type A was produced under in-vivo conditions by strains NY-5 and SF130, while ET type C was produced by strain T18. Differences between production of toxins in vitro and in vivo might be of significance for the understanding of the pathogenetic mechanisms in streptococcal infection.     

Compartmental Analysis of Breathing in the Supine and Prone Positions by Optoelectronic Plethysmography

Optoelectronic plethysmography (OEP) has been shown to be a reliable method for the analysis of chest wall kinematics partitioned into pulmonary rib cage, abdominal rib cage, abdomen, and right and left side in the seated and erect positions. In this paper, we extended the applicability of this method to the supine and prone positions, typically adopted in critically ill patients. For this purpose we have first developed proper geometrical and mathematical models of the chest wall which are able to provide consistent and reliable estimations of total and compartmental volume variations in these positions suitable for clinical settings. Then we compared chest wall (CW) volume changes computed from OEP( V _CW) with lung volume changes measured with a water seal spirometer (SP) ( V _SP)in 10 normal subjects during quiet (QB) and deep (DB) breathing on rigid and soft supports. We found that on a rigid support the average differences between V _SP and V _CW were –4.2% ± 6.2%, –3.0% ± 6.1%, –1.7% ±7.0%, and –4.5% ± 9.8%, respectively, during supine/QB, supine/DB, prone/QB, and prone/DB. On the soft surface we obtained –0.1% ± 6.0%, –1.8% ± 7.8%, 18.0% ± 11.7%, and 10.2% ± 9.6%, respectively. On rigid support and QB, the abdominal compartment contributed most of the V _CW in the supine (63.1% ± 11.4%) and prone (53.5% ± 13.1%) positions. V _CW was equally distributed between right and left sides. In the prone position we found a different chest wall volume distribution between pulmonary and abdominal rib cage (22.1% ± 8.6% and 24.4% ± 6.8, respectively) compared with the supine position (23.3% ± 9.3% and 13.6% ± 3.0%). © 2001 Biomedical Engineering Society. PAC01: 8763Lk, 8719Uv