Lallas Costas D, Auge Brian K, Raj Ganesh V, Santa-Cruz Robert, Madden John F, Preminger Glenn M
Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
J Endourol. 2002 Oct;16(8):583-90. doi: 10.1089/089277902320913288.
The ureteral access sheath has positively impacted ureteroscopy by decreasing operative times and increasing success rates. However, as previous studies have suggested that large-caliber endoscopes may cause ureteral ischemia, concern has been raised about the impact of access sheath insertion on ureteral blood flow. We sought to determine whether the access sheath compromises ureteral blood supply and, if so, causes ischemic damage to the ureter during ureteroscopic procedures.
Using a swine animal model, ureteral blood flow was measured with a laser Doppler flowmeter. Eleven ureteral units were randomized into four study groups: those dilated with 10F-12F, 12F-14F, and 14F-16F access sheaths (N = 3 per group) and an undilated control group (N = 2). Blood flow measurements were obtained from the proximal ureter via laser Doppler flowmetry for 70 minutes at 5-minute intervals. Hemodynamic variability was controlled for through intraoperative heart rate and oxygen saturation monitoring, as well as a second Doppler probe that was placed on the animal's skin, from which readings were also taken every 5 minutes. Results were correlated with histopathologic findings.
The control group demonstrated little ureteral blood flow variability over the course of 70 minutes. The study groups that were dilated with sheaths, however, all showed a decrease in ureteral blood flow after access sheath insertion, with the flow in animals dilated with 12F-14F and 14F-16F sheaths dropping below 50% of baseline. This initial drop in blood flow was followed by a gradual increase from nadir toward baseline values over the course of the study. On average, the 14F-16F group reached nadir more quickly and took longer to restore its ureteral blood flow. All animals remained hemodynamically stable throughout the study, showing only minimal variability in heart rate, oxygen saturation, and skin blood flow over the 70-minute experiment. Histologically, there was no evidence of ischemic damage in any of the study groups at 72 hours.
In this animal model, the access sheath does cause a transient decrease in ureteral blood flow. Nonetheless, compensatory mechanisms of the ureteral wall restore blood flow to near-baseline rates and preserve urothelial integrity, suggesting that use of the ureteral access sheath remains a safe adjunct to flexible ureteroscopy. Because the chronic effects of the access sheath have yet to be elucidated, care must be taken in selecting an appropriate-size sheath for each individual case. Preventive measures may be available to help avoid sheath-related ureteral injury in those patients identified as high risk.
输尿管通路鞘通过缩短手术时间和提高成功率，对输尿管镜检查产生了积极影响。然而，正如先前研究表明大口径内镜可能导致输尿管缺血一样，人们对通路鞘插入对输尿管血流的影响也产生了担忧。我们试图确定通路鞘是否会损害输尿管血液供应，如果会，在输尿管镜手术过程中是否会导致输尿管缺血性损伤。
使用猪动物模型，用激光多普勒血流仪测量输尿管血流。将11个输尿管单位随机分为4个研究组：分别用10F - 12F、12F - 14F和14F - 16F输尿管通路鞘扩张的组（每组n = 3）和未扩张的对照组（n = 2）。通过激光多普勒血流仪每隔5分钟从输尿管近端获取血流测量值，共70分钟。通过术中监测心率和血氧饱和度，以及在动物皮肤上放置的第二个多普勒探头（也每隔5分钟读取数据）来控制血流动力学变异性。结果与组织病理学发现相关。
对照组在70分钟内输尿管血流变化很小。然而，用通路鞘扩张的研究组在插入通路鞘后均显示输尿管血流减少，用12F - 14F和14F - 16F通路鞘扩张的动物血流降至基线的50%以下。血流的初始下降之后，在研究过程中从最低点逐渐向基线值增加。平均而言，14F - 16F组达到最低点更快，恢复输尿管血流所需时间更长。在整个研究过程中，所有动物血流动力学均保持稳定，在70分钟的实验中，心率、血氧饱和度和皮肤血流仅有极小的变化。组织学上，在72小时时，任何研究组均无缺血性损伤的证据。
在该动物模型中，输尿管通路鞘确实会导致输尿管血流短暂下降。尽管如此，输尿管壁的代偿机制可使血流恢复至接近基线水平，并保持尿路上皮完整性，这表明使用输尿管通路鞘仍是软性输尿管镜检查的安全辅助手段。由于通路鞘的长期影响尚未阐明，在为每个病例选择合适尺寸的通路鞘时必须谨慎。对于被确定为高危的患者，可能有预防措施来帮助避免与通路鞘相关的输尿管损伤。
