第2747期:What should you do if you cut off your finger?(2)

Surprisingly, severed tissues can survive for a few hours without these resources. And keeping them cool further slows the rate of tissue death, generally giving surgeons a 6-to-12-hour window for reattachment. But once the tissues die, reconnecting them won’t bring them back to life.令人惊讶的是，断裂的组织即使没有这些资源，也能存活几个小时。而将其保持低温则能进一步减缓组织坏死的速度，通常可以为外科医生争取 6 到 12 小时的再植时间。但一旦组织死亡，即使重新连接，也无法让它们“复活”。This tight timeline is especially challenging for surgeons. Due to the issues we’ve already mentioned, reattachment operations are fairly uncommon. So most hospitals don’t have the tools and expertise required to tackle these time-sensitive procedures. And even if they do, nerve repair is extremely tricky. With perfectly clean cuts, surgeons can attempt to stitch nerves back together directly. And when a cut is ragged, they may try to create nerve conduits— tunnels between nerve ends that can allow the nerves to reconnect over time. But neither these, nor any other surgical options, reliably restore movement and sensation.这紧迫的时间限制对外科医生来说尤其具有挑战性。由于前面提到的种种问题，再植手术相当罕见，因此大多数医院并没有应对这种时间敏感型手术所需的工具和专业技术。即便具备条件，神经修复也是极其棘手的工作。在切口整齐的情况下，外科医生可以尝试直接将神经缝合；而如果切口参差不齐，他们可能会尝试制作“神经导管”——一种连接神经断端的隧道，使神经能够随着时间重新连接。但无论是这些方法还是其他手术手段，都无法确保可靠地恢复肢体的运动和感觉。All these obstacles make it highly unlikely that a lost limb can be reattached. However, medical technology has developed another dependable solution for amputation: prosthetics. Today, prostheses come in countless forms to replace numerous body parts. Prosthetic legs are excellent for walking and running. Prosthetic arms have historically struggled to replicate our hands’ fine motor movements. However, new myoelectric prostheses can detect electrical activity in nearby muscles and then translate those signals into relatively precise movements.所有这些障碍使得断肢能够成功再植的可能性极低。然而，医学技术发展出了另一种可靠的截肢解决方案——假肢。如今，假肢的形式多种多样，可以替代人体的不同部位。假肢腿在行走和跑步方面表现出色；而假肢手臂在历史上一直难以复制人手的精细运动。然而，新的肌电假肢可以检测邻近肌肉的电活动，并将这些信号转化为相对精确的动作。But perhaps the most dramatic development in prosthetic technology is transcutaneous osseointegration. First successfully performed in 1990, this procedure surgically anchors a metal implant into the bone of the remaining limb. The bone then grows into the crevices of the metal, creating a permanent connection. These implants extend through a portal in the skin, and can be attached to any prosthesis, which solves a handful of common prosthetic issues. Where traditional prosthetics can be heavy, providing a direct skeletal connection makes their weight feel more natural. Osseointegrated prosthetics are also less likely to irritate the skin where they attach, and they can offer more sensation by transmitting forces like vibration through the implant to the bone.或许，假肢技术中最引人注目的发展是“经皮骨整合”技术。该技术于 1990 年首次成功实施，它通过手术将金属植入物固定在残肢的骨骼中，随后骨骼会长入金属的缝隙中，从而形成永久连接。这些植入物会穿出皮肤的开口，并可以连接到任何假肢上，从而解决了许多传统假肢的常见问题。传统假肢可能较为笨重，而直接的骨骼连接能让重量感更加自然。经皮骨整合假肢也不易刺激与之接触的皮肤，并且能够通过将震动等力量从植入物传递到骨骼，为使用者提供更多的感知。Even with all these new technologies, not everyone wants to replace or reattach a lost limb. After an amputation, some people opt to rely on their remaining limbs, with or without the help ofmobilityaids and other adaptive equipment.即便有了这些新技术，并不是每个人都希望替换或再植失去的肢体。截肢后，有些人选择依靠剩余的肢体生活，无论是否借助助行器或其他适应性设备。