髂骨螺钉松动四种翻修技术的生物力学比较

目的:比较松质骨填塞钉道、增加螺钉长度、传统聚甲基丙烯酸甲酯(polymethylmethacrylate,PMMA)强化钉道和外板开窗PMMA强化钉道四种方法翻修松动髂骨螺钉后的固定强度,探讨髂骨螺钉松动的理想补救手段。方法:8具成人防腐尸体骨盆标本,经双能X光吸收法测定骨密度后,将直径7.5mm髂骨短钉(长度为70mm)分别置入左右髂骨(A组),通过MTS材料实验机向螺钉尾部施加100～300N垂直循环载荷2000次后,测试髂骨螺钉的轴向拔出力。用松质骨紧密填塞两侧钉道后,在左侧钉道内置入短钉(B组),右侧钉道置入长度为100mm的髂骨长钉(C组),重复上述测试。将左侧钉道内注满PMMA后,再次置入髂骨短钉(D组);将另1枚髂骨短钉置入右侧钉道,以螺钉中点为中心沿螺钉轴线的髂骨外板处开窗,高度20mm、长度40mm、深度至内板皮质,灌注PMMA(E组);D组和E组重复上述测试。记录各组髂骨螺钉的轴向最大拔出力并进行比较。结果:8具标本的骨密度为0.75～0.91g/cm2,平均为0.85±0.05g/cm2。A～E组的最大拔出力分别为1174±542N、261±89N、769±317N、1954±623N和1820±659N,D组与E组比较无显著性差异(P0.05),D组与E组显著高于A、B和C组(P0.05),C组显著高于B组(P0.05),B组和C组显著低于A组(P0.05)。结论:松质骨填塞钉道和增加螺钉长度不能恢复髂骨螺钉的锚定强度;外板开窗PMMA强化和传统PMMA强化后置钉可使髂骨螺钉获得更高的锚定强度;从微创角度,外板开窗PMMA强化可能成为髂骨螺钉松动的理想补救手段。     

直入式注入聚甲基丙烯酸甲酯骨水泥强化椎弓根钉内固定治疗骨质疏松性胸腰椎骨折

目的 探讨应用直入式注入聚甲基丙烯酸甲酯(PMMA)骨水泥强化椎弓根钉内固定治疗骨质疏松性胸腰椎骨折的疗效.方法 2009年1月至2010年2月应用直入式注入PMMA骨水泥强化椎弓根钉内固定治疗14例骨质疏松性胸腰椎骨折患者,男9例,女5例;年龄50～72岁,平均61岁.临床疗效采用视觉模拟(VAS)疼痛评分、Frankel分级方法进行评定,应用X线片评估术后内固定效果.结果 14例患者中13例术后获6～22个月(平均18.4个月)随访,1例失访.VAS评分由术前平均7.9分降至术后平均1.2分,7例合并有神经损伤的患者Frankel分级术后平均改善1.2级,58枚椎弓根钉中54枚行直入式注入PMMA骨水泥强化,术后所有患者均未出现与骨水泥渗漏相关的神经损伤症状和体征.X线片示椎弓根螺钉未发生松动及脱出,周围无透亮线出现.后凸角由术前平均21.8°改善至术后平均10.3°,末次随访后凸角平均为14.3°,平均后凸角矫正丢失40°.结论 应用直入式注入PMMA骨水泥强化椎弓根钉内固定治疗骨质疏松性胸腰椎骨折可获得满意的临床疗效.

Abstract：

Objective To explore clinical outcomes of direct injection of polymethylmethacrylate (PMMA) to augment pedicle screw fixation for osteoporotic thoracolumbar fractures. Methods From January 2009 to February 2010, 14 patients with osteoporotic thoracolumbar fracture underwent spinal decompression and instrumentation with PMMA augmentation of pedicle screw by direct injection. They were 9 men and 5 women, aged from SO to 72 years (average, 61 years). The clinical outcomes were evaluated by the visual analog scale (VAS) and the Frankel scale. Radiologic findings were documented to assess postoperative internal fixation. Results All but one of the patients obtained a mean follow-up of 18. 4 months (from 6 to 22 months). The mean VAS scores of the patients improved from 7. 9 to 1. 2 points (P < 0. 01). Postoperatively, Frankel grading for the 7 patients with neurologic deficit improved by 1. 2 grades. Totally 54 of the 58 screws were augmented with PMMA. There was neither neurologic deterioration nor symptomatic cement leakage after surgery. X-ray plain films revealed no screw loosening, pullout or bright lines around screws. On average,kyphotic deformity was improved from 21. 8° preoperatively to 10. 3° postoperatively (P <0. 01), and returned to 14. 3° at the final follow-up. The average loss of kyphosis correction was 4°. Conclusion Pedicle screw fixation after vertebral augmentation with PMMA by direct injection can gain a satisfactory clinical outcome for patients with osteoporotic thoracolumbar fracture.     

Time course of activated coagulation time at various sites during continuous haemodiafiltration using nafamostat mesilate

Objective: To determine the adequate site of activated coagulation time (ACT) measurement during continuous haemodiafiltration (CHDF) using nafamostat mesilate. Design: Prospective, consecutive, clinical study. Setting: An intensive care unit of a general hospital. Patients: Ten patients with acute organ failure including kidney, lung and liver, caused by sepsis after major surgery. Interventions: A CHDF circuit with a haemofilter made of polymethylmethacrylate membrane was primed with 50 mg nafamostat in 500 ml saline, and was started at a circuit flow rate of 100 ml/min. Continuous injection of 0.5 mg/kg per h nafamostat, 700 ml/h of dialysis fluid and 1000 ml/h of filtrate fluid was set. Measurements and results: The circuit pressure at the inlet and outlet of the circuit were monitored, and ACT was measured every 2 h at the site of nafamostat injection, outlet, patient's artery and inlet until 24 h. A value of standard deviation of ACT at each site was regarded as the variation value of ACT. The circuit pressure did not change significantly. The ACT did not change significantly at any measurement site. The variation value of ACT at the inlet of the circuit was significantly lower than that at the site of nafamostat injection. Conclusions: The ACT value at the inlet of the circuit may be adequate to monitor anticoagulation during CHDF using nafamostat. Received: 9 July 1998 Final revision received: 28 January 1999 Accepted: 15 February 1999     

Polymethylmethacrylate bone cements and additives: A review of the literature

Polymethylmethacrylate (PMMA) bone cement technology has progressed from industrial Plexiglass administration in the 1950s to the recent advent of nanoparticle additives. Additives have been trialed to address problems with modern bone cements such as the loosening of prosthesis, high post-operative infection rates, and inflammatory reduction in interface integrity. This review aims to assess current additives used in PMMA bone cements and offer an insight regarding future directions for this biomaterial. Low index (< 15%) vitamin E and low index (< 5 g) antibiotic impregnated additives significantly address infection and inflammatory problems, with only modest reductions in mechanical strength. Chitosan (15% w/w PMMA) and silver (1% w/w PMMA) nanoparticles have strong antibacterial activity with no significant reduction in mechanical strength. Future work on PMMA bone cements should focus on trialing combinations of these additives as this may enhance favourable properties.     

磷酸钙骨水泥在椎体成形术中的实验研究

目的 :模仿椎体成形术观察磷酸钙骨水泥 /聚甲基丙烯酸甲酯植入椎体后与椎体界面间的组织学差异。方法 :将PMMA和CPC植入到犬椎体 ,通过X线、CT、光镜、扫描电镜观察 2种材料与椎体界面间的微观结构变化。结果 :PMMA与椎体之间的结合是单纯的机械连接未能达到生物机械固定 ,CPC与骨界面间无排异反应的表现 ,是直接的骨小梁与生物材料之间的生物连接。结论 :磷酸钙骨水泥是椎体成形术中的一种比较理想的替代材料     

经皮椎体成形术治疗骨质疏松性椎体压缩骨折

目的　探讨椎体成形术治疗骨质疏松性椎体压缩骨折的早期临床效果。方法　对 1 8例骨质疏松性椎体压缩骨折病人的2 0个椎体 ,经皮椎弓根向椎体内穿针并注入聚甲基丙烯酸甲酯 (PMMA)。结果　 1 8例病人平均每个椎体注入骨水泥 6 5ml,X线检查骨水泥充盈良好 ,骨折复位满意。术后 1 2h至 3d ,疼痛明显减轻或消失 ,应用视觉模拟评分法测试疼痛缓解 81 % ,术中术后无明显并发症出现。对 1 6例病人随访 3～ 6个月 ,疼痛未复发 ,椎体形态未见改变。结论　经皮椎体成形术治疗骨质疏松性椎体压缩骨折 ,能够迅速缓解疼痛 ,增加椎体的稳定性 ,是安全有效的微创技术     

椎体成形术中心肺功能变化的实验研究

目的:观察椎体成形术中的血液动力学和血气变化及是否发生肺脂肪栓塞。方法:将聚甲基丙烯酸甲酯注入到犬的L2椎体,记录术前、术后颈动脉血压和血气分析值,并将肺组织作病理检查。结果:平均2.6ml的骨水泥注入到椎体后(5±2)s导致颈动脉压下降,持续(150±35)s,并可导致血二氧化碳分压增高和pH值减小,氧分压减低,肺脏病理检查可见到小血管内有脂肪滴。结论:椎体成形术中注射骨水泥可能引起血压下降和肺脂肪栓塞,是椎体成形术的潜在并发症。     

骨静脉造影在椎体成形术治疗症状性椎体血管瘤中的价值探讨

目的 评价经皮椎体成形术(PVP)治疗症状性椎体血管瘤的安全性、临床疗效,探讨术中先行椎体骨静脉造影是否能降低骨水泥(PMMA)渗漏的发生及提高临床疗效.方法 2001年3月至2010年1月,南京东南大学附属中大医院放射科治疗椎体血管瘤患者45例共53节,均有不同程度胸背部或腰背部疼痛,其中马尾受压瘫痪1例,椎体压缩骨折3例.分为两组:A组为先行椎体骨静脉造影后再注入PMMA共23例27节椎体;B组为直接注入PMMA 22例26节.PVP后1～3 dCT复查观察PMMA分布及有无椎体周围渗漏.比较两组疗效、PMMA渗漏情况、注入量、手术成本及术中X线辐射时间.结果 PVP技术成功率100%,PMMA平均注入量3.96 ml.随访6个月～5年,除A组初期1例无效外,余44例术后1周疼痛均有改善,术后1、3个月疼痛进一步减轻,6个月及1年疗效均保持稳定,CR、PR和NR分别为84.5%、13.3%、2.2%.6个月时,A组有效率为95.7%,B组为100%,两组比较差异无统计学意义(P=0.323).CT证实PMMA椎旁渗漏共有8节,均无临床症状,其中A组有6节,B组有2节(P=0.140).A组平均注入PMMA量为3.70 ml,B组为4.23 ml(P=0.157);A组平均手术费用为7.24千元/节,B组为5.84千元/节(P=0.000),B组比A组节省约1.4千元/节;A组平均X线照射时间为13.28 min,B组为8.78 min(P=0.000),B组比A组减少约4.5 min.结论 PVP为椎体血管瘤安全、有效的治疗方法;技术要领为经血管瘤侧椎弓根穿刺,PMMA应完全充填血管瘤并部分超出其边缘;椎体骨静脉造影不能提高PVP疗效和安全性,相反增加了手术成本和X线照射时间.     

早期综合干预联合左甲状腺素钠治疗妊娠合并甲状腺功能减退症的临床研究

目的 探讨早期综合干预联合左甲状腺素钠治疗妊娠合并甲状腺功能减退症的临床效果及其对生化指标的影响。方法 将2012年1月至2016年12月遵化市人民医院收治的194例妊娠合并甲状腺功能减退症病人按随机数字表法分为研究组(97例)和对照组(97例),对照组病人给予早期综合干预治疗,研究组病人给予早期综合干预联合左甲状腺素钠治疗。观察两组病人治疗后分娩结局(妊娠终止、自然分娩、阴道助产、剖宫产)、母婴结局(产后出血、宫缩乏力、胎儿窘迫及新生儿窒息)以及预后效果,同时检测治疗前后相关生化指标[游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、促甲状腺刺激激素(TSH)、人绒毛膜促性腺激素(hCG)和脂联素(ADPN)]和社会支持评定量表(SSRS)评分变化。结果 联合治疗后研究组病人妊娠终止率(5.15%比22.68%)、剖宫产率(6.19%比26.80%)、产后出血率(10.31%比35.05%)、宫缩乏力率(9.28%比36.08%)、胎儿窘迫率(11.34%比34.02%)及新生儿窒息率(10.31%比31.96%)低于治疗后的对照组(χ² 值依次=12.43、14.97、16.93、19.87、14.23、13.64,均P<0.001),自然分娩率68(70.10%)、总有效率93(95.88%)高于治疗后的对照组[30(30.93%)、71(73.20%)](均P<0.05),而治疗后两组病人阴道助产率比较差异无统计学意义 (P>0.05);治疗后两组病人生化指标(FT3、FT4、hCG和ADPN)和SSRS评分高于治疗前,而TSH低于治疗前(P<0.05);与治疗后对照组相比,治疗后研究组病人生化指标(FT3、FT4、hCG和ADPN)和SSRS评分升高,而TSH降低(P<0.05)。结论 早期综合干预联合左甲状腺素钠可有效改善妊娠合并甲状腺功能减退症病人分娩结局、母婴结局、生化指标以及预后。