Department of Urology, University of Pittsburgh, Pittsburgh, PA.
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA.
Am J Obstet Gynecol. 2021 Jan;224(1):78.e1-78.e7. doi: 10.1016/j.ajog.2020.07.005. Epub 2020 Jul 21.
Stress urinary incontinence carries a significant healthcare burden for women worldwide. Single incision slings are minimally invasive mesh devices designed to treat stress urinary incontinence. For prolapse repair, meshes with higher porosity and lower structural stiffness have been associated with improved outcomes.
In this study, we compared the higher stiffness, lower porosity Altis sling with the lower stiffness, higher porosity Solyx sling in an ovine model. We hypothesized that SIS-B would have a negative impact on the host response.
A total of Altis and Solyx single incision slings were implanted suburethrally into sheep according to the manufacturer's instructions on minimal tension. The mesh-urethral-vaginal complex and adjacent ungrafted vagina (no mesh control) were harvested en bloc at 3 months. Masson's trichrome and picrosirius red staining of 6 μm thin sections was performed to measure interfiber distance and tissue integration. Smooth muscle contractility to a 120 mM KCl stimulus was performed in an organ bath to measure myofiber-driven contractions. Standard biochemical assays were used to quantify glycosaminoglycan, total collagen, and elastin content, and collagen subtypes. Bending stiffness was performed in response to a uniaxial force to define susceptibility to folding/buckling. Statistical analysis was performed using Mann-Whitney, Gabriel's pairwise post hoc, Wilcoxon matched-pairs, and chi-square tests.
The animals had similar ages (3-5 years), parity (multiparous), and weights (45-72 kg). Trichrome cross sections showed that the Altis sling buckled in a "C" or "S" shape in most samples (8 of 11), whereas buckling after Solyx sling implantation was observed in only a single sample (1 of 13; P=.004). Tissue integration, as measured by the presence of collagen or smooth muscle between the mesh fibers on trichrome 4× imaging, was increased in samples implanted with the Solyx sling compared with the Altis sling (P<.05). Total collagen content decreased significantly with both products when compared with the ungrafted vagina consistent with stress shielding. There was no difference in the 2 groups with regard to glycosaminoglycan or elastin content. The Altis sling mesh tissue complex demonstrated significantly higher amounts of both collagen types I and III than the Solyx sling-implanted tissue and the ungrafted control. Smooth muscle contractility in response to 120 mM KCl was decreased after implantation of both slings compared with the sham (P=.011 and P<.01), with no difference between mesh types (P=.099). Bending stiffness in the Altis sling was more than 4 times lower than in the Solyx, indicating an increased propensity to buckle (0.0186 vs 0.0883).
The structurally stiffer Altis sling had decreased tissue integration and increased propensity to buckle after implantation. Increased collagen types I and III after the implantation of this device suggests that these changes may be associated with a fibrotic response. In contrast, the Solyx sling largely maintained a flat configuration and had improved tissue integration. The deformation of the Altis sling is not an intended effect and is likely caused by its lower bending stiffness. Both meshes induced a decrease in collagen content and smooth muscle contractility similar to previous findings for prolapse meshes and consistent with stress shielding. The long-term impact of buckling warrants further investigation.
压力性尿失禁给全球女性带来了巨大的医疗负担。单切口吊带是一种微创网片装置，旨在治疗压力性尿失禁。对于脱垂修复，具有更高孔隙率和更低结构刚度的网片与改善的结果相关。
在这项研究中，我们在绵羊模型中比较了更高刚度、更低孔隙率的 Altis 吊带和更低刚度、更高孔隙率的 Solyx 吊带。我们假设 SIS-B 会对宿主反应产生负面影响。
根据制造商的最小张力说明，将 Altis 和 Solyx 单切口吊带完全植入尿道下。在 3 个月时，整块采集网片-尿道-阴道复合体和相邻未移植阴道（无网片对照）。对 6μm 薄切片进行 Masson 三色和 picrosirius 红染色，以测量纤维间距离和组织整合。在器官浴中进行 120mM KCl 刺激的平滑肌收缩，以测量肌纤维驱动的收缩。使用标准生化测定法定量糖胺聚糖、总胶原和弹性蛋白含量以及胶原亚型。在响应单轴力时进行弯曲刚度，以确定对折叠/弯曲的易感性。使用 Mann-Whitney、Gabriel 的成对事后、Wilcoxon 配对检验和卡方检验进行统计分析。
动物的年龄（3-5 岁）、产次（多胎）和体重（45-72kg）相似。三色交叉切片显示，在大多数样本中（11 个中的 8 个），Altis 吊带呈“C”或“S”形弯曲，而在 Solyx 吊带植入后，仅在单个样本中观察到弯曲（13 个中的 1 个；P=.004）。与 Altis 吊带植入物相比，Solyx 吊带植入物的组织整合度（通过网片纤维之间存在胶原或平滑肌来测量）增加（P<.05）。与未移植阴道相比，两种产品的总胶原含量均显著降低，这与应力屏蔽一致。糖胺聚糖或弹性蛋白含量在两组之间没有差异。与 Solyx 吊带植入组织和未移植对照组相比，Altis 吊带网片组织复合物显示出明显更高水平的 I 型和 III 型胶原。与 sham 相比，两种吊带植入物后对 120mM KCl 的平滑肌收缩均降低（P=.011 和 P<.01），但网片类型之间无差异（P=.099）。Altis 吊带的弯曲刚度比 Solyx 吊带高 4 倍以上，表明其弯曲的倾向更大（0.0186 与 0.0883）。
结构更硬的 Altis 吊带在植入后组织整合度降低，弯曲倾向增加。该装置植入后 I 型和 III 型胶原增加表明这些变化可能与纤维化反应有关。相比之下，Solyx 吊带在很大程度上保持平坦的形态，并具有更好的组织整合度。Altis 吊带的变形不是预期的效果，很可能是由于其较低的弯曲刚度造成的。两种网片都导致胶原含量和平滑肌收缩性降低，类似于先前对脱垂网片的发现，与应力屏蔽一致。弯曲的长期影响值得进一步研究。
