Mechanics of Uterosacral Ligaments: Current Knowledge, Existing Gaps, and Future Directions

Roles and mechanisms of biomechanical-biochemical coupling in pelvic organ prolapse

Pelvic organ prolapse (POP) is a significant contributor to hysterectomy among middle-aged and elderly women. However, there are challenges in terms of dedicated pharmaceutical solutions and targeted interventions for POP. The primary characteristics of POP include compromised mechanical properties of uterine ligaments and dysfunction within the vaginal support structure, often resulting from delivery-related injuries. Fibroblasts secrete extracellular matrix, which, along with the cytoskeleton, forms the structural foundation that ensures proper biomechanical function of the fascial system. This system is crucial for maintaining the anatomical position of each pelvic floor organ. By systematically exploring the roles and mechanisms of biomechanical-biochemical transformations in POP, we can understand the impact of forces on the injury and repair of these organs. A comprehensive analysis of the literature revealed that the extracellular matrix produced by fibroblasts, as well as their cytoskeleton, undergoes alterations in patient tissues and cellular models of POP. Additionally, various signaling pathways, including TGF-β1/Smad, Gpx1, PI3K/AKT, p38/MAPK, and Nr4a1, are implicated in the biomechanical-biochemical interplay of fibroblasts. This systematic review of the biomechanical-biochemical interplay in fibroblasts in POP not only enhances our understanding of its underlying causes but also establishes a theoretical foundation for future clinical interventions.

Case report: Emergency management of unilateral herniation of bowel and a bilateral defect of the broad ligament in a resource limited setting

INTRODUCTION

Broad ligament herniation is a rare type of internal hernia, presenting as a diagnostic challenge. An exploratory laparotomy can be performed to definitively diagnose and treat the defect.

CASE PRESENTATION

A 36-year-old female, with no known comorbids and no significant past medical and surgical history presented with acute abdominal pain, multiple episodes of vomiting, and absolute constipation. After clinical and radiologic investigations, the diagnosis of an internal herniation of small bowel to the broad ligament was suspected. An emergent exploratory laparotomy was then performed. Intra-operatively it was found that she had a bilateral defect to the broad ligament and a unilateral broad ligament hernia (BLH). Postoperatively she remained vitally stable and was discharged home.

CLINICAL DISCUSSION

We report a rare case of a unilateral broad ligament hernia with a bilateral defect. Diagnosis of BLH is associated with diagnostic uncertainty mainly due to its rarity and nonspecific presentation.

CONCLUSION

Although broad ligament herniation is rare, it is a significant cause of intestinal obstruction and may result in complications if not attended to timely. Early diagnosis and management is necessary to minimize associated morbidity and mortality that can occur as a consequence of bowel ischemia and necrosis.

Diagnostic Value of Dynamic Magnetic Resonance Imaging (dMRI) of the Pelvic Floor in Genital Prolapses

Pelvic organ prolapse is a chronic disease resulting from a weakening of the musculoskeletal apparatus of the pelvic organs. For the diagnosis of this pathology, it is insufficient to conduct only a clinical examination. An effective diagnostic tool is the method of dynamic magnetic resonance imaging (MRI) of the pelvic floor, which allows a comprehensive assessment of the anatomical and functional characteristics of the walls of the pelvis and pelvic organs. The aim of the study was to analyze the literature data on the possibilities and limitations of using dynamic MRI in pelvic organ prolapse. The widespread use of the dynamic MRI method is due to the high quality of the resulting image, good reproducibility, and the maximum ability to display the characteristics of the pelvic floor. Dynamic MRI of the small pelvis allows a comprehensive assessment of the anatomical and functional features of the pelvis, excluding the effect of ionizing radiation on the body. The method is characterized by good visualization with high resolution and excellent soft tissue contrast. The method allows for assessing the state of the evacuation function of visualized structures in dynamics. Simultaneous imaging of all three parts of the pelvic floor using dynamic MRI makes it possible to assess multicompartment disorders. The anatomical characteristics of the state of the pelvic organs in the norm and in the event of prolapse are considered. The technique for performing the method and the procedure for analyzing the resulting images are described. The possibilities of diagnosing a multicomponent lesion are considered, while it is noted that dynamic MRI of the pelvic organs provides visualization and functional analysis of all three parts of the pelvis and often allows the choice and correction of tactics for the surgical treatment of pelvic organ prolapse. It is noted that dynamic MRI is characterized by a high resolution of the obtained images, and the advantage of the method is the ability to detect functional changes accompanying the pathology of the pelvic floor.

Ex Vivo Uniaxial Tensile Properties of Rat Uterosacral Ligaments

This manuscript presents new experimental methods for testing the ex vivo tensile properties of the uterosacral ligaments (USLs) in rats. The USL specimens ([Formula: see text]) were carefully dissected to preserve their anatomical attachments, and they were loaded along their main in vivo loading direction (MD) using a custom-built uniaxial tensile testing device. During loading, strain maps in both the MD and the perpendicular direction (PD) were collected using the digital image correlation technique. The mean (± S.E.M.) maximum load and displacement at the maximum load were [Formula: see text] N and [Formula: see text] mm, respectively. The USLs were found to be highly heterogeneous structures, with some specimens experiencing strains in the MD that were lower than [Formula: see text] and others reaching strains that were up to [Formula: see text] in the intermediate region. At 0.5 kPa stress, a value reached by all the specimens, the mean strain in the MD was [Formula: see text] while at 5 kPa stress, a value achieved only by 9 out of the 21 specimens, the mean strain increased to [Formula: see text]. Under uniaxial loading, the specimens also elongated in the PD, with strains that were one order of magnitude lower than the strains in the MD; at the 0.5 kPa stress, the mean strain in the PD was recorded to be [Formula: see text] and, at the 5 kPa stress, the strain in the PD was [Formula: see text]. The directions of maximum principal strains remained almost unchanged with the increase in stress, indicating that little microstructural re-organization occurred due to uniaxial loading. This study serves as a springboard for future investigations on the supportive function of the USLs in the rat model by offering guidelines on testing methods that capture their complex mechanical behavior.

Bilateral medial sacrospinous ligament suture for apical suspension through natural spaces: A single-center study with low perioperative complications

Sacrospinous ligament fixation (SSLF) is one of the most used native tissue approaches for apical suspension with a high rate of perioperative complications. This study aimed to review cases undergoing a modified SSLF and assess its perioperative adverse events. It was a retrospective study of 168 consecutive patients undergoing modified transvaginal SSLF at a single tertiary center from 2017 to 2021. The sutures were placed on the sacrospinous ligament (SSL) approaching the sacrum through natural spaces under direct vision. Moreover, it was performed bilaterally. Patient demographics and perioperative complications were reviewed. The median age was 65 years, and 85.7% (144/168) had stage III-IV prolapse. Among the 168 patients undergoing this modified SSLF, 161 were for uterovaginal prolapse, and seven were for posthysterectomy vaginal vault prolapse. 83.9% (135/161) patients were concomitant with hysterectomy, and 70.2% (118/168) were with anteroposterior colporrhaphy. The median operation time was 82 min (interquartile range [IQR], 61-100 min), and the median intraoperative blood loss was 50 ml (IQR, 30-50 ml). Two cases had pelvic hematoma, and both were cured after expectant treatment. No patient required a homologous blood transfusion, and none complained about buttock or lower limb pain 2 weeks postoperatively. Nor did injury of the ureters, bladder, or rectum occur intraoperatively. This modified transvaginal SSLF procedure was safe and had no severe perioperative complications.

Transcriptome and metabolome analyses reveal the interweaving of immune response and metabolic regulation in pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

The pathogenesis of pelvic organ prolapse (POP) remains unknown. Herein, we aim to reveal the molecular profile of POP by transcriptomic and metabolomic analysis.

METHODS

We selected 12 samples of uterosacral ligaments (USLs) from 6 POP patients and 6 controls for transcriptomic and metabolomic analyses. Differentially expressed genes (DEGs) were identified using the R package edgeR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using clusterProfiler, and a protein-protein interaction (PPI) network was constructed using STRING and visualized in Cytoscape. Metabolomic profiling was performed by a liquid chromatography-tandem mass spectrometry system.

RESULTS

Transcriptomic analysis identified 487 DEGs between the POP and control groups. Functional enrichment analysis revealed that they were mostly related to immune response terms, including "adaptive immune response," "T cell differentiation," and "T cell activation." In addition, PTPRC, LCK, CD247, IL2RB, CD2, CXR5, JUN, CD3E, IL2RG, and PRF1 were the 10 nodes with the highest node degrees in the PPI network. Metabolomic profiling revealed 290 differentially expressed metabolites, which significantly enriched in "glycerophospholipid metabolism," "nicotinate and nicotinamide metabolism," "glycine, serine, and threonine metabolism," "arginine and proline metabolism," "pyrimidine metabolism," and "purine metabolism." Finally, integrated analysis revealed that the DEGs involved in these significantly enriched metabolic pathways included NT5C1A, GMPR, SDS, ALAS2, CARNS1, PYCR1, P4HA3, PGS1, and NMRK2.

CONCLUSIONS

Our findings demonstrate that the immune response and metabolic regulatory pathways are intertwined in POP and might provide new therapeutic targets.

In-plane and out-of-plane deformations of gilt utero-sacral ligaments

The uterosacral ligaments (USLs) are supportive structures of the uterus and apical vagina. The mechanical function of these ligaments within the pelvic floor is crucial not only in normal physiological conditions but also in reconstructive surgeries for pelvic organ prolapse. Discrepancies in their anatomical and histological description exist in the literature, but such discrepancies are likely due to large variations of these structures. This makes mechanical testing very challenging, requiring the development of advanced methods for characterizing their mechanical properties. This study proposes the use of planar biaxial testing, digital image correlation (DIC), and optical coherence tomography (OCT) to quantify the deformations of the USLs, both in-plane and out-of-plane. Using the gilts as an animal model, the USLs were found to deform significantly less in their main direction (MD) of in vivo loading than in the direction perpendicular to it (PD) at increasing equibiaxial stresses. Under constant equibiaxial loading, the USLs deform over time equally, at comparable rates in both the MD and PD. The thickness of the USLs decreases as the equibiaxial loading increases but, under constant equibiaxial loading, the thickness increases in some specimens and decreases in others. These findings could contribute to the design of new mesh materials that augment the support function of USLs as well as noninvasive diagnostic tools for evaluating the integrity of the USLs.