磁性矫正器治疗槌状指畸形的实验研究

目的:探讨槌状指畸形磁性矫正器治疗槌状指畸形的可行性。方法:将新鲜尸体手指标本植入相应大小的永磁铁钉,观察其伸指和屈指效果,分析此方法治疗槌状指畸形的可行性。结果:5例手指标本剔除皮肤、筋膜等软组织,保留手指伸、屈指肌腱,置入永磁铁钉后,根据Dargan功能评定法评定手指关节功能:优3例,良1例,可1例,差0例,优良率为80%。15例手指标本在保留所有组织后,模拟临床进行手术,采用掌侧入路植入相应大小的永磁铁钉,根据Dargan功能评定法评定术后患指关节功能:优10例,良4例,可0例,差1例,评分优良率为93.3%。所有标本术后的屈指活动范围与术前无区别。结论:槌状指畸形磁性矫正器治疗槌状指畸形具有可行性。     

16-bit CT图像读取金属植入物CT值的应用

目的 探讨16-bit CT图像在读取金属植入物CT值中的应用价值。方法 于模体中间分别插入一圆柱形铝棒、钛合金棒和不锈钢棒,对模体进行CT扫描,对图像重建获得12-bit和16-bit CT图像。分析并比较3种金属棒的12-bit和16-bit图像及其CT值。结果 对于同种金属棒,12-bit图像和16-bit图像显示效果基本相同。铝棒周围未显示出伪影;钛合金棒周围有较明显的放射状伪影;不锈钢棒周围有严重伪影。3种金属棒内部的显示无明显差异。12-bit和16-bit图像中,铝棒的最大CT值分别为2 159 HU和2 150 HU,平均CT值分别为2 026 HU、2 021 HU;钛合金棒的最大CT值分别为3 071 HU和6 950 HU,平均CT值分别为3 071 HU、5 957 HU;不锈钢棒的最大CT值分别为3 071 HU和12 060 HU,平均CT值分别为3 071 HU、9 397 HU。结论 16-bit的CT图像能够显示体内金属植入物的CT值分布,分辨出铝、钛合金或不锈钢的金属植入物。     

Optimal side of implant for single-lead VDD pacing: right-sided versus left-sided implantation

BACKGROUND: Atrial undersensing occurs in a considerable number of patients with single-lead VDD pacing. This study tried to determine the role of implant side in maintenance of the VDD mode in patients with isolated atrioventricular (AV) block. METHODS: Eighty-two patients with isolated AV block (46 females; mean age, 58 +/- 17 years) received a single-lead VDD pacemaker (Medtronic Kappa, n = 70 and St. Jude Medical Affinity, n = 12). The patients were randomly assigned to one of two implantation groups (group I: right-sided VDD and group II: left-sided VDD). In each group, the P-wave amplitudes were determined at implantation, predischarge, 2-month, and 6-month follow-up. At each follow-up visit, stored event histograms of pacemaker were also retrieved. The atrial sensing measurements were compared between two groups. RESULTS: Implantation was easier from right side (1.7 +/- 1.0 vs 2.8 +/- 1.7 attempts, P = 0.001). Implant P-wave was higher in group I compared to group II (4.2 +/- 1.7 vs 2.7 +/- 1.0 mV, P < 0.0001). During follow-up, higher P-wave amplitudes were obtained in group I both at predischarge (2.6 +/- 1.3 vs 1.4 +/- 1.1 mV, P < 0.0001), 2-month (2.8 +/- 1.8 vs 1.3 +/- 1.0 mV, P < 0.0001), and 6-month (2.9 +/- 1.7 vs 1.3 +/- 0.9 mV, P < 0.0001) evaluations but remained stable throughout the 6 months in both groups. After implantation, VDD function was better maintained in group I than group II (100% vs 90%, P = 0.026). Incidence of atrial undersensing was lower in group I than group II (P = 0.026) in last follow-up visit. CONCLUSIONS: Implant side has a significant influence on atrial sensing performance in single-lead VDD pacing. Thus, right-side implantation should be the preferred approach for the implantation of VDD single-lead systems.     

Epidermoid carcinoma of the anal canal

During the past ten years, substantial progress has been made in the knowledge of the natural history of epidermoid carcinoma of the anal canal and of the response of the disease to radiotherapy alone or combined with chemotherapy. At the present time, the main problem in the management of this tumor concerns identification of the best modalities to achieve local control and preservation of anal function. From a series of 276 cases, followed for more than three years, the necessity for a careful pretreatment evaluation was stressed. This included a systematic search for pelvic metastatic lymph nodes by palpation and CT scan. All patients were treated initially by irradiation except those who underwent groin dissection for inguinal node metastasis or colostomy for complete anal obstruction. Three groups of patients have been identified: 1) unresectable or disseminated tumors (33 cases), 2) resectable tumors but not suitable for sphincter conservation (21 cases) treated by radiochemotherapy and delayed surgery, and 3) resectable tumors suitable for sphincter conservation (222 cases) which were treated by a split-course regimen combining a short course of carefully planned external beam irradiation (19 days) followed by an iridium 192 implant after a two-month rest. In this group, which represents 80 percent of the whole series, 80 percent of patients have had their cancer controlled and 90 percent of controlled patients have retained normal anal function. The use of chemotherapy during the first days of irradiation is advisable in all cases to reinforce the efficacy of treatment and increase the chance of anal preservation. Results of the split-course regimen, combining external beam and interstitial irradiation, demonstrate a clear superiority over external beam irradiation alone, especially for large infiltrating tumors, which represent the majority of cases.     

Effects of Femoral Component Size on Proximal Tibial Strain With Anatomic Graduated Components Total Knee Arthroplasty

Survivorship in total knee arthroplasty (TKA) is multifactorial and dependent upon alignment, ligament balance, patient characteristics, and implant factors. The contribution of each factor leading to implant loosening is not well known. This study defined the effect of femoral component sizing relative to tibial size on loading patterns in the proximal tibia. Changes in strain were measured in tibiae implanted with appropriately sized metal-backed tibial components loaded with 2 sizes of femoral components. Significant increases of shear strain up to 126% were measured in peripheral regions of the tibia when loaded with a larger vs a smaller femoral component. Increased peripheral loading in the proximal tibia could predispose to a higher risk of cancellous overload and failure. Limiting stress concentrations in the periphery of the proximal tibia by considering sizing relationships between femoral and tibial components may decrease osseous strains and the likelihood of bony overload in TKA.     

Accuracy of Implant Positioning for Minimally Invasive Total Knee Arthroplasty in Patients With Severe Varus Deformity

Minimally invasive surgery (MIS) in total knee arthroplasty (TKA) reportedly yields decreased patient morbidity and a rapid return of function, but how much deformity can be accepted for MIS-TKA remains unclear. This study investigated 238 knees from 218 consecutive patients who underwent MIS-TKA. Patients were divided into groups with tibiofemoral mechanical axis (TFM) 195° or greater and TFM less than 195°, then clinical and radiographic results were compared. Similar improvements in knee score at 3 months postoperatively were obtained in the both groups, whereas radiographic accuracy of the coronal alignment in the TFM ≥195° group was inferior to that in TFM <195° group. Postoperative TFM was significantly worsened in patients with lateral bowing angle of the femoral shaft (LBFS) 4° or greater, and 53% of patients in the TFM ≥195° group displayed LBFS 4° or greater, explaining the inferior radiographic accuracy in this group compared with the TFM <195° group. These results indicate that use of MIS techniques decreases radiographic accuracy, particularly in patients with severe genu varum and increased LBFS.     

慢性局限型牙周炎患者牙种植修复长期疗效的临床观察

目的：观察慢性局限型牙周炎患者经完善的牙周治疗后,再行牙种植修复后的远期疗效。方法：对21例局部牙缺失、临床曾诊断为慢性局限型牙周炎但病情控制良好的患者,共植入43颗种植体。二期修复负载后随访5年。结果：有4例5颗种植体骨整合失败、拔除,38颗种植体骨整合良好,总成功率为88.37%;需要GBR/ERE技术支持的种植体成功率为76.92%,其他为93.33%。负载5年后,全景片上测量分析种植体周围边缘骨吸收为（1.33±0.22）mm,需要GBR/ERE技术支持的骨吸收量为（1.60±0.30）mm,高于牙周炎轻者的（1.02±0.32）mm。结论：在慢性局限型牙周炎病情得到良好控制的情况下,行牙种植修复长期效果良好,但是牙周炎的严重程度影响种植体的成功率及承载年限。     

小型猪上颌窦内提升穿破上颌窦粘膜同期植入种植体的骨结合情况的研究

目的观察上颌窦内提升术中窦底粘膜穿通对同期植入的种植体骨结合的影响,以及生物膜的应用效果。方法试验用小型猪3只,X线确定上颌窦底位置,全麻下拔除小型猪双侧上颌相应位置的牙,6个种植位点随机分为3组,实验A组穿破窦底同期植入种植体,实验B组穿破窦底粘膜加生物膜同期植入种植体,对照组窦底粘膜完整。术后6个月观察大体标本,做X线检查,做带种植体的骨磨片,观察种植体的骨结合情况及窦底的愈合情况。结果大体标本显示种植体无松动,A组种植体暴露在上颌窦内,B组与对照组窦底粘膜完整。X线显示3组的种植体周围的骨质均匀,没有阴影。骨磨片镜下观察骨结合情况,3组没有差别。结论上颌窦底粘膜的穿通对种植体骨结合没有影响,窦底粘膜穿通后加生物膜有利于窦底粘膜的愈合。