The Effect of Perineal Wound Infection on the Anal Sphincter

Study Overview
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Brief Summary
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Perineal injury following childbirth can result in complications such as wound infection. The perineum has closely related anatomical structures including the external genital organs and the anal triangle which contains the anal sphincter muscles. Therefore as wound infection can extend and as muscles of the perineum sit in such close proximity to each other, the anal sphincter muscles could potentially be affected. This could also potentially include cases of perineal injury where the anal sphincter was not injured. However ultrasound has never been used to investigate this. Endoanal ultrasound is the gold standard diagnostic tool in the assessment of obstetric anal sphincter injury. The anal sphincter can also be visualised using multiplanar transperineal ultrasound(three/four-dimensional. Therefore both modalities could be used. However, it has been shown that transperineal ultrasound has a high positive predictive value and therefore is able to correctly identify an intact anal sphincter, but low positive predictive value; meaning poor detection of sphincter defects. Therefore, although it cannot completely substitute endoanal ultrasound (the gold standard in investigating obstetric anal sphincter injuries), it provides and adjunct/alternative for women who cannot tolerate endoanal ultrasound. The investigators plan to perform an observational study to evaluate to the natural history of perineal wound infections. Patients will be assessed weekly with endoanal ultrasound and/or transperineal ultrasound until the wound infection has resolved and the wound has clinically healed. If a bacterial wound swab has not been taken prior to recruitment or wound swab results are not available, one will be taken to detect the causative organisms. Appropriate antibiotics will then be given to cover the detected organism. Bacterial burden and will also be measured weekly using the MolecuLight i:X; a bacterial autofluorescence camera which captures the presence and load of bacteria. In wounds that have superficially dehisced; exact wound measurements including wound surface area, depth, volume and healing progress will be precisely measured using the Silhouette® 3D camera

Official Title
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A Prospective Observational Study Evaluating the Sonographic Appearance of the Anal Sphincter in Women With Perineal Wound Infection Following Vaginal Delivery.

Conditions
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Obstetric Trauma, Perineum; Injury, Perineal Infection, Anal Sphincter Injury

Intervention / Treatment
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* Diagnostic Test: Three-dimensional Endoanal Ultrasound
* Diagnostic Test: Transperineal Ultrasound(multiplanar)
* Diagnostic Test: The MolecuLight i:X: Bacterial autofluorescence camera
* Device: Silhouette® 3D camera: Three-dimensional wound measuring camera


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Women with childbirth related perineal injury and wound infection Women over 18 years of age Ability to understand and read the patient information sheet (in English) Ability to give informed consent Exclusion Criteria: Vulnerable Adult Fetal or neonatal death or poor neonatal outcome Women who are in an immunosuppressive state (e.g human immunodeficiency virus or pharmacologically induced immunodeficiencies by chemotherapy or steroids) Inability to give consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Three-dimensional Endoanal Ultrasound|Three-dimensional endoanal ultrasound is the gold standard diagnostic tool in the assessment of obstetric anal sphincter injury. The anorectal transducer is inserted directly into the anal canal which allows assessment of the anal sphincter complex. Patients will be assessed at weekly intervals with until the wound infection has resolved and the wound has clinically healed.|
|Diagnostic Test: Transperineal Ultrasound(multiplanar)|If endoanal ultrasound is declined or not tolerated, the anal sphincter will also be assessed using three-/four-dimensional (3D/4D) transperineal ultrasound with the probe placed externally on the area of the fourchette. Patients will be assessed at weekly intervals with until the wound infection has resolved and the wound has clinically healed.|
|Diagnostic Test: The MolecuLight i:X: Bacterial autofluorescence camera|The bacterial load of the perineal wound will be measured every week using the MolecuLight i:X. This is a system, which uses fluorescent illumination to capture and document the presence of bacteria. Patients will be assessed at weekly intervals with until the wound infection has resolved and the wound has clinically healed. These findings will be supported by microbiological analysis of the wound fluid with swab culture and sensitivity.|
|Device: Silhouette® 3D camera: Three-dimensional wound measuring camera|For wound that have superficially dehisced, the wound surface area, depth, volume and healing progress will be precisely measured using the Silhouette® 3D camera. This is a system that uses 3D laser technology to track wound healing progression.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in sphincter defect 3-point radial angle | Endoanal ultrasound and/or transperineal ultrasound will be performed to assess involvement of the anal sphincter. Anal sphincter defects will measured on both modalities with a 3-point angle, with the angle vertex in the middle of the anal canal. The 3D volume will be assessed at the deep, superficial, and subcutaneous levels for defects. A change in radial angle size will be measured. On transperineal ultrasound the extent of the defect will be measured circumferentially using a 3-point radial angle(0 degrees being no defect). A change in radial angle size will be measured. | Baseline until wound infection resolved and wound healed, or up to 16 weeks | 
| Change in sphincter defect Stark Score | On endoanal ultrasound, anal sphincter defects will also be scored using a validated Starck score which accounts for depth, length and size of the defect for both internal and external anal sphincter, with a range from 0 being no defect to 16 being maximal defect. Therefore, a change in this score will be measured. | Baseline until wound infection resolved and wound healed, or up to 16 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in bacterial fluorescence patterns | The bacterial load of the perineal wound will be measured every week using the MolecuLight i:X. This is a system, which uses fluorescent illumination to capture and document the presence of bacteria. | Baseline until wound infection resolved and wound healed, or up to 16 weeks | 
| Change in wound dimensions | Change in total wound size using the Silhouette® 3D camera. | Baseline until wound infection resolved and wound healed, or up to 16 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obstetric Anal Sphincter Injury, Childbirth related perineal trauma, Perineal wound infection, Endoanal ultrasound, Transperineal ultrasound, 3D Ultrasound, 4D Ultrasound