Dataset Information

Validation of an ovine vesicovaginal fistula model.

ABSTRACT:

Introduction and hypothesis

A representative, large animal model of vesicovaginal fistulas is needed for the training of surgeons and for the development of new surgical techniques and materials for obstetric fistula repair.

Methods

The safety, feasibility, and reproducibility of vesicovaginal fistula creation were studied in 4 adult female sheep. A 1-cm fistula was created between the vagina and the bladder through a transvaginal approach. The defect was allowed to heal for 8 weeks and the animals were then euthanized. The primary outcome was the fistula patency. Secondary outcomes were fistula size, urogenital dimensions, urodynamic evaluation, histology (inflammation, vascularization, collagen deposition) and biomechanical characteristics of the fistula edge (stress at break, maximum elongation, and stiffness).

Results

The transvaginal creation of a vesicovaginal fistula was safe. All animals survived the surgical procedure and follow-up period, without complications. Three of the four animals demonstrated a patent vesicovaginal fistula after 8 weeks. Baseline data are provided of the urogenital dimensions and the urodynamic, histological, and biomechanical characteristics of the model.

Conclusions

The ewe is a safe, feasible, and reproducible model for vesicovaginal fistulas. The model can help to study new techniques and materials to boost surgical innovation for vesicovaginal fistula repair.

SUBMITTER: Maljaars LP

PROVIDER: S-EPMC9569284 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature

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Publications

Validation of an ovine vesicovaginal fistula model.

Maljaars Lennart P LP Jeffery Stephen T ST Scholten Marlou M Kaestner Lisa L Jere Khumbo K Bezuidenhout Deon D Guler Zeliha Z Roovers Jan-Paul W R JWR

International urogynecology journal 20220919 11

<h4>Introduction and hypothesis</h4>A representative, large animal model of vesicovaginal fistulas is needed for the training of surgeons and for the development of new surgical techniques and materials for obstetric fistula repair.<h4>Methods</h4>The safety, feasibility, and reproducibility of vesicovaginal fistula creation were studied in 4 adult female sheep. A 1-cm fistula was created between the vagina and the bladder through a transvaginal approach. The defect was allowed to heal for 8 wee ...[more]

PMID: 36121458

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Project description:Study objectiveTo establish face and construct validity for a novel variation of American College of Obstetrics and Gynecology "Flowerpot Model" for transvaginal hysterectomy (TVH) surgical simulation with improved vesicovaginal dissection during surgical education simulation.DesignCross-sectional face and construct validation study using the "Flowerpot Model." The vesicovaginal dissection plane was modified to include additional felt and balloon materials to simulate the bladder.SettingSingle academic center.ParticipantsFourteen residents and fellows, postgraduate year (PGY) 2 to 6, subdivided into junior (n = 8) with ≤10 prior TVH surgeries and senior groups (n = 6) with >10 prior TVH surgeries performed.InterventionsAll subjects watched a brief introductory video and then were filmed simulating a TVH.Measurements and main resultsFor face validity, subjects completed an anatomic checklist and pre/post simulation satisfaction survey. For construct validation, 2 independent, blinded expert surgeons (M.A. and J.M.) graded films using the Global Rating Scale of Operative Performance (GRS). Primary outcome was mean GRS between groups. The junior group consisted of PGY 2 to 3 with ≤ 10 prior TVH, median 7.5 (interquartile range [IQR] 6.75) and senior group PGY 3 to 6 with >10 TVH, median 19 (IQR 10) (p <.01). Subjects were "satisfied" or "very satisfied" with bladder and anterior peritoneal fold simulation (92%) and found vesicovaginal dissection "realistic" (100%). GRS score was significantly different between groups (juniors, 19.5 [IQR 5] vs seniors, 28.5 [IQR 8.5]; p = .048). Intergrader correlation was high (ρ = 0.87, p <.01). Surgeon volume of prior TVH was not significantly correlated to average GRS score, ρ = 0.49 (p = .10). The model improved comfort and confidence scores in the junior group more than senior group (p = .04), but senior group still had higher post simulation confidence scores than the junior group (p = .02).ConclusionFace and construct validity with the modified Flowerpot Model was demonstrated. This low fidelity model is capable of simulation of a TVH with a novel vesicovaginal dissection. Prior surgical experience was not correlated to GRS score or time to procedure completion.

Project description:OBJECTIVE:To develop a risk score to identify women with vesicovaginal fistula at high risk of residual urinary incontinence after surgical repair. METHODS:We conducted a prospective cohort study among 401 women undergoing their first vesicovaginal fistula repair at a referral fistula repair center in Lilongwe, Malawi, between September 2011 and December 2014, who returned for follow-up within 120 days of surgery. We used logistic regression to develop a risk score to identify women with a high likelihood of residual urinary incontinence, defined as incontinence grade 2-5 within 120 days of vesicovaginal fistula repair, based on preoperative clinical and demographic characteristics (age, number of years with fistula, human immunodeficiency virus status, body mass index, previous repair surgery at an outside facility, revised Goh classification, Goh vesicovaginal fistula size, circumferential fistula, vaginal scaring, bladder size, and urethral length). The sensitivity, specificity, and positive and negative predictive values of the risk score at each cut point were assessed. RESULTS:Overall, 11 (3%) women had unsuccessful fistula closure. Of those with successful fistula closure (n=372), 85 (23%) experienced residual incontinence. A risk score cut point of 20 had sensitivity of 82% (95% confidence interval [CI] 72-89%) and specificity 63% (95% CI 57-69%) to potentially identify women with residual incontinence. In our population, the positive predictive value for a risk score cut point of 20 or higher was 43% (95% CI 36-51%) and the negative predictive value was 91% (95% CI 86-94%). Forty-eight percent of our study population had a risk score 20 or greater and, therefore, would have been identified for further intervention. CONCLUSION:A risk score of 20 or higher was associated with an increased likelihood of residual incontinence with satisfactory sensitivity and specificity. If validated in alternative settings, the risk score could be used to refer women with a high likelihood of postoperative incontinence to more experienced surgeons.

Dataset Information

Validation of an ovine vesicovaginal fistula model.

Introduction and hypothesis

Methods

Results

Conclusions

Publications

Validation of an ovine vesicovaginal fistula model.

Similar Datasets

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