IHU-Strasbourg, Institute of Image-Guided Surgery, Strasbourg, France.
Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy.
Surg Endosc. 2019 Oct;33(10):3200-3208. doi: 10.1007/s00464-018-6603-4. Epub 2018 Nov 19.
Endoscopic submucosal dissection allows for "en bloc" removal of early gastrointestinal neoplasms. However, it is technically demanding and time-consuming. Alternatives could rely on energy-based techniques. We aimed to evaluate a predictive numerical model of thermal damage to preoperatively define optimal laser settings allowing for a controlled ablation down to the submucosa, and the ability of confocal endomicroscopy to provide damage information.
A Nd:YAG laser was applied onto the gastric mucosa of 21 Wistar rats on 10 spots (total 210). Power settings ranging from 0.5 to 2.5W were applied during 1-12 s, with a consequent energy delivery varying from 0.5 to 30 J. Out of the 210 samples, a total of 1050 hematoxilin-eosin stained slides were obtained. To evaluate thermal injury, the ratio between the damage depth (DD) over the mucosa and the submucosa thickness (T) was calculated. Effective and safe ablation was considered for a DD/T ratio ≤ 1 (only mucosal and submucosal damage). Confocal endomicroscopy was performed before and after ablation. A numerical model, using human physical properties, was developed to predict thermal damage.
No full-thickness perforations were detected. On histology, the DD/T ratio at 0.5 J was 0.57 ± 0.21, significantly lower when compared to energies ranging from 15 J (a DD/T ratio = 1.2 ± 0.3; p < 0.001) until 30 J (a DD/T ratio = 1.33 ± 0.31; p < 0.001). Safe mucosal and submucosal ablations were achieved applying energy between 4 and 12 J, never impairing the muscularis propria. Confocal endomicroscopy showed a distorted gland architecture. The predicted damage depth demonstrated a significant positive linear correlation with the experimental data (Pearson's r 0.85; 95% CI 0.66-0.94).
Low-power settings achieved effective and safe mucosal and submucosal ablation. The numerical model allowed for an accurate prediction of the ablated layers. Confocal endomicroscopy provided real-time thermal damage visualization. Further studies on larger animal models are required.
内镜黏膜下剥离术可实现早期胃肠肿瘤的整块切除。然而，该技术要求高、耗时。替代方法可能依赖于基于能量的技术。我们旨在评估一种热损伤的预测数值模型，以便术前确定最佳激光设置，从而实现可控的黏膜下消融，并评估共聚焦内镜提供损伤信息的能力。
在 21 只 Wistar 大鼠的胃黏膜上应用 Nd:YAG 激光，共进行 10 个点的治疗（共 210 个点）。在 1-12 秒内应用 0.5-2.5W 的功率设置，相应的能量传递范围为 0.5-30J。在 210 个样本中，共获得了 1050 张苏木精-伊红染色切片。为了评估热损伤，计算损伤深度（DD）与黏膜和黏膜下层厚度（T）的比值。当 DD/T 比值≤1 时（仅为黏膜和黏膜下层损伤），认为是有效和安全的消融。在消融前后进行共聚焦内镜检查。使用人体物理特性开发了一种数值模型来预测热损伤。
未发现全层穿孔。组织学上，0.5J 时的 DD/T 比值为 0.57±0.21，与 15J（DD/T 比值=1.2±0.3；p<0.001）至 30J（DD/T 比值=1.33±0.31；p<0.001）的能量范围相比显著降低。应用 4-12J 能量可实现安全的黏膜和黏膜下层消融，从不损伤固有肌层。共聚焦内镜显示腺体结构扭曲。预测的损伤深度与实验数据呈显著正线性相关（Pearson r 0.85；95%CI 0.66-0.94）。
低功率设置可实现有效的、安全的黏膜和黏膜下层消融。数值模型可实现对消融层的准确预测。共聚焦内镜可实时显示热损伤。需要在更大的动物模型上进行进一步研究。
