Augmentation cystoplasty using decellularized vermiform appendix in rabbit model

An International Consensus Survey among Pediatric Surgeons on the Role of Appendectomy in Malrotation

Introduction

Ladd's procedure, originally described in 1936 for the treatment of malrotation, does not traditionally include appendectomy as a standard step. We conducted a multinational survey to investigate the current consensus on the role of appendectomy in Ladd's procedure.

Methodology

An anonymous online survey was distributed to pediatric surgeons worldwide. The survey collected demographic data and explored surgical preferences related to the management of malrotation. Open-ended questions were used to assess the opinions regarding the necessity of appendectomy, decision-making factors, and complications associated with appendectomy during Ladd's procedure.

Results

A total of 343 responses were received from 46 countries. Of the respondents, 319 (93%) were consultants and 24 (7%) were residents/trainees. When asked about the choice between open and laparoscopic Ladd's procedure, 292 (85%) preferred open surgery. Overall, 184 (53%) respondents favored appendectomy in both open and laparoscopic Ladd's procedure. Furthermore, 172 (50%) surgeons advocated for appendectomy in all malrotation cases, citing concerns about potential future appendicitis. While differences existed between all comparisons, none of them reached statistical significance. The factors influencing the decision to preserve the appendix included the risk of postoperative complications and the potential future use of the appendix as a surgical conduit. The surgical complications following appendectomy included surgical site infections in 14 (33%) patients, adhesive obstruction in 13 (31%) patients, intrabdominal abscesses in 10 (24%) patients, and fecal fistulas in 5 (12%) patients.

Conclusion

The majority of surgeons aim to perform appendectomy in all malrotation cases, considering the potential risks and benefits of this approach. These findings offer valuable insights for clinical practice and may inform future guidelines and decision-making algorithms.

Appendectomy as part of Ladd's procedure: a systematic review and survey analysis

BACKGROUND

Ladd's Procedure has been the surgical intervention of choice in the management of congenital intestinal malrotation for the past century. Historically, the procedure included performing an appendectomy to prevent future misdiagnosis of appendicitis, since the location of the appendix will be shifted to the left side of the abdomen. This study consists of two parts. A review of the available literature on appendectomy as part of Ladd's procedure and then a survey sent to pediatric surgeons about their approach (to remove the appendix or not) while performing a Ladd's procedure and the clinical reasoning behind their approach.

METHODS

The study consists of 2 parts: (1) a systematic review was performed to extract articles that fulfill the inclusion criteria; (2) a short online survey was designed and sent by email to 168 pediatric surgeons. The questions in the survey were centered on whether a surgeon performs an appendectomy as part of the Ladd's procedure or not, as well as their reasoning behind either choice.

RESULTS

The literature search yielded five articles, the data from the available literature are inconsistent with performing appendectomy as part of Ladd's procedure. The challenge of leaving the appendix in place has been briefly described with minimal to no focus on the clinical reasoning. The survey demonstrated that 102 responses were received (60% response rate). Ninety pediatric surgeons stated performing an appendectomy as part of the procedure (88%). Only 12% of pediatric surgeons are not performing appendectomy during Ladd's procedure.

CONCLUSION

It is difficult to implement a modification in a successful procedure like Ladd's procedure. The majority of pediatric surgeons perform an appendectomy as part of its original description. This study has identified gaps in the literature pertaining to analyze the outcomes of performing Ladd's procedure without an appendectomy which should be explored in future research.

Augmentation cystoplasty in dogs: A comparative study of different tunica vaginalis grafts

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Tunica vaginalis allograft and sheep tunica vaginalis decellularized extracellular matrix successfully rebuilt the bladder wall with minor complications in dogs.

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Sheep tunica vaginalis xenograft has disappointing results in the canine model since the bladders became contracted with decreased capacity.

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Tunica vaginalis grafts represent a simple and low-cost choice for augmentation cystoplasty in dogs.

In veterinary practice, numerous urological disorders that cause bladder dysfunction necessitate augmentation cystoplasty (AC). The purpose of this study is to evaluate the dog tunica vaginalis allograft (DTVA), sheep tunica vaginalis xenograft (STVX) and sheep tunica vaginalis decellularized extracellular matrix (STVDEM) as graft materials for urinary bladder (UB) reconstruction following a 45±5% cystectomy model in dogs. In this study, 18 adult apparently healthy mongrel dogs of both sexes were divided into three groups (6 dogs each): the DTVA group, the STVX group, and the STVDEM group. The evaluation of the AC in different groups was carried out using clinical, hematological, serum biochemical, urine, ultrasonographic, retrograde positive cystogram, and histopathological analysis all over the study period of 12 weeks. The dogs in all groups survived the procedures, except three dogs died from both STVX and DTVA groups. The mean bladder capacity indicated that the DTVA and STVX groups had regained 82.22% and 68.62%, respectively, of their preoperative baseline capacity. Interestingly, the STVDEM group's bladder capacity increased to 113.70%. Although histological analysis revealed that the three grafts successfully rebuilt the bladder wall, the STVDEM demonstrated well-organized and well-differentiated epithelial and muscular tissues that resembled, but were not identical to, native UB tissues. As a result, STVDEM is proposed as an ideal and potential acellular graft for UB reconstruction in dogs, whereas DTVA and STVX could be employed in emergencies requiring UB reconstruction.

Regeneration of muscular wall of the bladder using a ureter matrix graft as a scaffold

We investigated a method for bladder augmentation in rats using a decellularized ureter graft. We used 16 rats divided into two groups of eight. After partial cystectomy, the bladders in group 1 were grafted with a 1 cm² patch of human decellularized ureter. Rats in group 2 were untreated controls. Biopsies of the graft were taken at 1, 3 and 9 months postoperatively for histological investigation. Total removal of cells and preservation of extracellular matrix (ECM) was confirmed in the decellularized ureter. Histological examination after 1 month revealed few cells at the border of the graft. Three months after the operation, the graft was infiltrated by vessels and smooth muscle and the mucosal lining was complete. All bladder wall components resembled native bladder wall by 9 months after implantation. CD34, CD31, α-smooth muscle actin, S100, cytokeratin AE1/AE3 and vimentin were detected 9 months after the operation. We demonstrated the potential of decellularized biocompatible ureteric grafts for use as a natural collagen scaffold for bladder repair in rats.

In-vivo regeneration of bladder muscular wall with whole decellularized bladder matrix: A novel hourglass technique for duplication of bladder volume in rabbit model

OBJECTIVE

To determine histological aspects of decellularized bladder graft to achieve a double-sized bladder by novel hourglass technique; using rabbit models.

METHODS

Sixteen rabbit bladders were decellularized and underwent laboratory investigations. After making a laparotomy incision and exposure of bladders in another 16 rabbits (partial detrusor myomectomy), they were separated into two groups. The fundus of the decellularized scaffold was anastomosed to the fundus of the native bladder via the serosal layer, and the omentum and a double-J stent were placed in the decellularized bladder by no direct contact with the urine (Group A, n=8). In group B (n=8), the bladder was augmented applying the decellularized bladder that was in contact with the urine. After 6 months, the omentum was brought out of the neck of the engineered bladder and the anastomosis was opened. Biopsies were taken at 1, 3, and 9 months postoperatively.

RESULTS

Cell removal with preservation of extracellular matrix structure was confirmed in decellularized bladders. Histological examination after 1 month demonstrated few cells at the border of the grafts. After 3 months, the region of the graft was indistinguishable from the natural bladder with continuity of transitional epithelium of natural bladder on the decellularized grafted scaffolds. The organization of muscle layers was similar to native bladder muscle layers after 9 months. IHC staining markers were highly expressed after 9 months. Interestingly, bladders had a high fibrosis grade in group B compared with hourglass technique.

CONCLUSION

We confirmed that decellularized bladder may be a reliable scaffold and viable material for bladder augmentation.

Use of the extracellular matrix from the porcine esophagus as a graft for bladder enlargement

INTRODUCTION

Some patients with diseases that involve increased bladder pressure or low-capacity bladders may need bladder enlargement surgery. In current techniques for bladder enlargement, autologous tissue such as small intestine or colon tissue is used to perform cystoplasties, which is far from ideal for these patients. In search of biomaterials with appropriate regeneration and safety profiles, tissue engineering has resulted in preclinical studies with acellular matrices in animal models that have yielded positive preliminary results with respect to the urothelial cell and smooth muscle repopulation; these studies have primarily been performed with matrices originating from the bladder or intestinal submucosa.

OBJECTIVE

The aim of the study was to assess an extracellular matrix device derived from the porcine esophagus for augmentation cystoplasty in an animal model.

STUDY DESIGN

Seven male Wistar rats weighing 357-390 g were subjected to augmentation cystoplasty with a circular segment of the acellular matrix from the porcine esophagus. Daily postoperative follow-up was performed with evaluation of changes in body weight, behavior, and wound status.

RESULTS

During follow-up, there were no complications associated with the process. Three specimens were sacrificed at day 30, and three, at day 60. Necropsy was performed, with a description of the macroscopic findings and a morphological study. Epithelialization was observed, with different stages of mucosal development in all specimens analyzed. Repopulation of smooth muscle cells, mixed inflammatory infiltrate, and vascular neoformation were identified in the matrices.

DISCUSSION

The urothelium and fibers of the smooth muscle were observed inside the implanted matrix. Additional investigations in larger animal models that allow urodynamic evaluation of the bladder with the matrix implanted are needed. However, to compare the results of this study model with those reported in the literature, a matrix derived from an organ different from the bladder was used because it could prevent the use of an intestinal segment in augmentation cystoplasty.

CONCLUSION

The acellular porcine esophagus matrix offers positive results regarding the repopulation of the urothelium and smooth muscle when used in augmentation cystoplasty in a murine model.

Decellularized human fetal intestine as a bioscaffold for regeneration of the rabbit bladder submucosa

PURPOSE

We aim to report a method to create a natural acellular scaffold from human fetal small intestine for augmentation cystoplasty in rabbits.

METHODS

Fetal intestines were decellularized by immersion in a hypotonic solution. The success of this protocol was evaluated by histological analysis, scanning electron microscopy and measurement of collagen and sulfated glycosaminoglycan of the acellular tissues. Eight mature rabbits were selected and acellular scaffolds were implanted on the exposed urothelium. Urodynamic studies and cystography were performed after six months. At 14, 120 and 180days animals were sacrificed and augmented bladders were resected.

RESULTS

Histological analysis revealed formation of muscular layer and blood vessels in implanted scaffolds similar to normal bladder. These findings demonstrate the effective seeding of scaffold by host bladder cells. The tissue architecture of recellularized scaffold was similar to the native bladder.

CONCLUSIONS

Fetal intestine acellular matrix could be an exceptional scaffold for bladder augmentation cystoplasty and may pave the road for future studies in order to be used for clinical application.

A novel technique for simultaneous whole-body and multi-organ decellularization: umbilical artery catheterization as a perfusion-based method in a sheep foetus model

The aim of this study was to develop a method to generate multi-organ acellular matrices. Using a foetal sheep model have developed a method of systemic pulsatile perfusion via the umbilical artery which allows for simultaneous multi-organ decellularization. Twenty sheep foetuses were systemically perfused with Triton X-100 and sodium dodecyl sulphate. Following completion of the whole-body decellularization, multiple biopsy samples were taken from different parts of 21 organs to ascertain complete cell component removal in the preserved extracellular matrices. Both the natural and decellularized organs were subjected to several examinations. The samples were obtained from the skin, eye, ear, nose, throat, cardiovascular, respiratory, gastrointestinal, urinary, musculoskeletal, central nervous and peripheral nervous systems. The histological results depicted well-preserved extracellular matrix (ECM) integrity and intact vascular structures, without any evidence of residual cellular materials, in all decellularized bioscaffolds. Scanning electron microscope (SEM) and biochemical properties remained intact, similar to their age-matched native counterparts. Preservation of the collagen structure was evaluated by a hydroxyproline assay. Dense organs such as bone and muscle were also completely decellularized, with a preserved ECM structure. Thus, as shown in this study, several organs and different tissues were decellularized using a perfusion-based method, which has not been previously accomplished. Given the technical challenges that exist for the efficient generation of biological scaffolds, the current results may pave the way for obtaining a variety of decellularized scaffolds from a single donor. In this study, there have been unique responses to the single acellularization protocol in foetuses, which may reflect the homogeneity of tissues and organs in the developing foetal body.