VATS Extraction of a Migrating Kirschner Wire Into the Mediastinum and Lung

IntroductionKirschner wires (K-wires) and Steinman pins have been used to fix fractures of the thorax, perhaps less frequently nowadays because of the appearance of better devices such as titanium plates and screws. Migration of these metallic wires and pins into different intrathoracic structures has been reported and may lead to catastrophic events. It is very important to follow up with these patients as long as the wires and pins remain in place.Here the authors report a case of a K-wire transmediastinal migration into the left upper lobe.Case ReportAn asymptomatic 46-year-old man fell down at his workplace and sought medical consultation because of the accident. In the emergency department, a chest radiograph revealed that a K-wire used to fix a right clavicular fracture 34 years previously had migrated through the anterior mediastinum and into the left upper lobe (Figure 1).A chest computed tomography (CT) showed that the K-wire migrated through the anterior mediastinum into the left upper lobe (Figures 2A and 2B). In addition, a chest CT showed that the K-wire was encroaching on the left brachiocephalic vein, posing a risk to extraction of the foreign body (Figure 3A), and that it was anterior to the aortic arch (Figure 3B).Once the diagnosis was made, extraction of the K-wire was planned through a left video-assisted thoracoscopic (VATS) approach as shown in Figures 4-8 and Videos 1 and 2. The patient was intubated with a single lumen endotracheal tube and CO2 insufflation was used (6 – 8 mmHg/4L/min).The patient’s postoperative recovery was uneventful, and he was discharged on the third postoperative day.DiscussionThe migration of K-wires and Steinman pins used for thoracic osteosynthesis has been reported to occur from the immediate postoperative period to many years after the surgery (1). In the present case, the migration was diagnosed 34 years after the osteosynthesis of a right clavicular fracture. The migration of these metallic foreign bodies has been described to occur to the mediastinum, trachea, lungs, aorta, pulmonary artery, innominate vein, pericardium, heart, esophagus, and spinal cord, leading to fatal complications (1)The mechanisms of migration are speculative and perhaps multifactorial: a) great freedom of shoulder movements with traction of the muscles on the metallic wires or pins; b) negative intrathoracic pressure; c) respiratory movements; d) gravitational forces; and e) local bone resorption making the wires and pins loose (1, 2).Zhang and colleagues (3) reported an interesting case of migration of a K-wire not bent over at the distal end, used to fix a right third rib fracture, into the right ventricle. The patient was asymptomatic and the diagnosis was made during a routine examination. There was no pain or other symptoms or signs, and the echocardiogram did not show pericardial effusion, although it did display the K-wire inside the right ventricle. The foreign body was removed through a median sternotomy on cardiopulmonary bypass. As in this report (3), the authors’ patient was asymptomatic and the diagnosis of the migrating K-wire was incidental. There was no chest pain, cough, or hemoptysis.Zhang and colleagues mentioned that the most common primary site of fixation from where the migration occurred into the heart was the sternoclavicular joint followed in order by the clavicle, the acromioclavicular joint, and the proximal humerus (3). Intracardiac migration has also been reported from the pelvic bone, the femur, and the finger (3). In the latter scenarios, peripheral intravascular embolization to the heart may be the explanation (4).The surgical approach to removing the foreign body depends on its anatomic location. Sternotomy, thoracotomy, or preferably thoracoscopy have been successfully used (4). Martins and colleagues (5) reported a 50-year-old woman who had a left humerus fracture fixed with K-wires. Sixteen years later, a chest CT demonstrated that one of the wires had migrated to the left lung. The K-wire was successfully removed by a VATS approach.In the case discussed here, a left VATS approach with a single lumen endotracheal tube and CO2 insufflation was used. The surgical team was prepared for a sternotomy if necessary. Another surgical strategy discussed was to remove the K-wire through a cervicotomy like in a transcervical thymectomy, using the Cooper’s sternal retractor and simultaneous videothoracoscopic control, which would allow the authors a good visualization of the brachiocephalic trunk and innominate vein, since encroaching on these vascular structures was a concern. In addition, through the cervicotomy, a partial sternotomy could be easily performed if necessary. The final decision was to start with videothoracoscopy with sternotomy capability arranged.It is important to emphasize that patients who have such orthopedic pins and wires must be followed up with chest radiographs as long as they have these devices in place. They must be removed as soon as any dislocation is detected or when the treatment of the fracture is concluded.View the rest of this article at: http://www.ctsnet.org/article/vats-extraction-migrating-kirschner-wire-mediastinum-and-lung

引言：克氏钢丝（K-wires）和斯坦曼针（Steinman pins）曾用于胸廓骨折的固定，尽管由于钛板和螺钉等更佳设备的出现，其使用频率可能有所降低。这些金属钢丝和针的迁移至不同的胸腔内结构已有报道，并可能导致灾难性事件。在钢丝和针仍在原位的情况下，对患者进行跟踪随访至关重要。在本研究中，作者报告了一例K钢丝经纵隔迁移至左侧上肺叶的病例。病例报告：一名46岁的无症状男性在工作场所摔倒后寻求医疗咨询。在急诊科，胸部X光片显示，用于固定34年前右侧锁骨骨折的K钢丝已通过前纵隔迁移至左侧上肺叶（图1）。胸部计算机断层扫描（CT）显示K钢丝已通过前纵隔迁移至左侧上肺叶（图2A和2B）。此外，胸部CT显示K钢丝正侵犯左侧锁骨下静脉，存在移除异物时的风险（图3A），并且位于主动脉弓前方（图3B）。一旦确诊，计划通过左侧视频辅助胸腔镜（VATS）手术取出K钢丝，如图4-8和视频1和2所示。患者通过单腔气管插管进行气管插管，并使用CO2充气（6-8 mmHg/4L/min）。患者术后恢复顺利，于术后第三天出院。讨论：用于胸骨固定术的K钢丝和斯坦曼针的迁移已报道从术后即刻至手术多年后发生（1）。在本例中，迁移发生在右侧锁骨骨折固定术后的34年后。这些金属异物的迁移已描述为可能迁移至纵隔、气管、肺、主动脉、肺动脉、无名静脉、心包、心脏、食管和脊髓，导致致命并发症（1）。迁移的机制尚不确定，可能是多因素导致的：a）肩部运动幅度大，肌肉对金属钢丝或针的牵引；b）胸腔内负压；c）呼吸运动；d）重力作用；e）局部骨吸收使钢丝和针松动（1, 2）。张等（3）报道了一例未在远端弯曲的K钢丝的迁移案例，该钢丝用于固定右侧第三肋骨骨折。患者无症状，诊断是在常规检查中发现的。没有疼痛或其他症状或体征，超声心动图未显示心包积液，尽管它显示了右心室内的K钢丝。异物是通过心肺转流下的胸骨正中切口取出的。正如本报告（3）中所述，作者的患者无症状，迁移的K钢丝的诊断是偶然发现的。没有胸痛、咳嗽或咯血。张等提到，最常见的固定原发部位是锁骨胸锁关节，其次是锁骨、肩锁关节和近端肱骨（3）。来自骨盆骨、股骨和手指的心内迁移也有报道（3）。在后一种情况下，可能是由于外周血管栓塞至心脏（4）。移除异物的手术方法取决于其解剖位置。胸骨切开术、胸腔切开术或更倾向于胸腔镜手术已被成功应用（4）。马丁斯等（5）报道了一位50岁的女性，她的左肱骨骨折用K钢丝固定。16年后，胸部CT显示其中一根钢丝已迁移至左肺。通过VATS方法成功取除了K钢丝。在本讨论的病例中，使用单腔气管插管和CO2充气进行了左侧VATS手术。手术团队准备必要时进行胸骨切开术。另一种讨论的手术策略是通过颈切开术移除K钢丝，类似于经颈纵隔甲状腺切除术，使用库珀胸骨牵开器和同时视频胸腔镜控制，这可以使作者获得对锁骨下干和锁骨下静脉的良好可视化，因为侵犯这些血管结构是一个关注点。此外，通过颈切开术，如果需要，可以轻松进行部分胸骨切开术。最终的决定是先进行具有胸骨切开术能力的视频胸腔镜手术。重要的是强调，只要患者体内有这种骨科针和钢丝，就必须通过胸部X光片进行随访。一旦发现任何移位或骨折治疗结束时，就必须立即取出这些装置。请访问http://www.ctsnet.org/article/vats-extraction-migrating-kirschner-wire-mediastinum-and-lung查阅本文的其余部分。