Preventing Isthmocele After Cesarean Section

Study Overview
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Brief Summary
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Cesarean section accounts for nearly 30% of births in Canada, and is the most commonly performed surgery by Obstetrician Gynecologists. Cesarean scar isthmocele, meaning a defect in the uterine wall at the site of a previous uterine incision, is a common complication of this surgery. While most are likely asymptomatic, isthmoceles can lead to major complications in pregnancy (uterine rupture, invasive placentation, cesarean scar ectopic pregnancy) and outside of pregnancy (abnormal uterine bleeding, infertility and pain). Studies have shown that the method used to suture the uterus at the time of a cesarean section may have an impact on the incidence of post-operative isthmocele formation. Our study is a randomized control trial of the impact of locked vs unlocked uterine closure at cesarean section on the incidence of isthmocele formation. Women undergoing cesarean section will be randomized to have either a locked or unlocked uterine closure. They will then return 6 months after their surgery for a transvaginal ultrasound to evaluate the presence or absence of an isthmocele. This study is a pilot trial. The investigators hope to determine the feasibility of completing a large randomized control trial by recording: a) the number of patient who agree to participate in this study, b) the number of patients who receive the correct intervention and, c) the number of patients who return for their post operative ultrasound. The investigators also plan to assess multiple secondary outcomes. First, the goal is to determine the isthmocele incidence within the study subjects of the pilot trial in order to perform a power calculation for a subsequent larger trial in this area. Another goal is to determine if the uterine closure techniques in this study lead to differences in surgical time, blood loss or the need for intra- or post-operative blood transfusion. Last, the study will collect data on the suture material most commonly used in this study to determine if this requires standardization in the subsequent larger trial.

Detailed Description
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Cesarean section accounts for nearly 30% of all deliveries in Canada, and is the most commonly performed surgery by Obstetrician Gynecologists (OBGYNs) in Canada. Therefore, it is important to understand the short and long-term complications of this procedure. Recently, emphasis has been placed on cesarean scar isthmocele as a long-term complication. An isthmocele is a defect at the cesarean section scar site with a depth of at least 1-2mm. Isthmoceles can lead to major obstetrical complications such as cesarean scar pregnancy, invasive placentation, and uterine rupture. More commonly, patients present with gynecologic symptoms: abnormal uterine bleeding, pain, and infertility. Up to 30-50% of patients with an isthmocele report symptoms when inquired. Isthmoceles have an incidence of 19-88% following cesarean section. This wide range is due to discrepancies in study technique, diagnostic criteria, and patient characteristics. While medical and surgical treatment options are available for cesarean scar isthmocele, our focus should turn to prevention at the time of cesarean section. Evidence suggests double-layer (vs. single-layer) uterine closure decreases the formation of cesarean scar isthmocele and increases residual myometrial thickness (RMT). Additionally, uterine closure with a locked suturing technique may result in greater isthmocele depth and size, and a thinner RMT at the cesarean scar site. To our knowledge however, no study has determined the impact of a locked vs. unlocked double-layer closure technique on isthmocele prevention. Locked sutures, believed to be more hemostatic, may cause tissue necrosis and impair wound healing. Interestingly, evidence does not support reductions in operative blood loss with locked closure techniques. The hypothesis is that unlocked double-layer uterine closure can reduce isthmocele formation and thus improve longterm maternal outcomes without impacting operative blood loss or other short-term surgical outcomes.

Official Title
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The PICS Trial: A Pilot Randomized Controlled Trial of Non-Locked vs. Locked Uterine Closure at Cesarean Section for Prevention of Uterine Isthmocele Formation

Conditions
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Cesarean Section Complications, Uterine Scar Diverticulum, Uterine Scar From Previous Cesarean Delivery

Intervention / Treatment
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* Procedure: Non-Locking Uterine Closure
* Procedure: Locked Uterine Closure


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Women undergoing their first cesarean section Exclusion Criteria: previous uterine hysterotomy (caesarean section, myomectomy, etc.) known uterine anomalies active labour known bleeding disorder maternal connective tissue disorders

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants will be randomized to either locked or non-locked uterine closure at the time of cesarean section.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Locked Uterine Closure<br>Participants will undergo two-layer closure of the hysterotomy site at the time of cesarean section. The first layer will use a running & locking technique. The second layer will be performed based on surgeon preference. | Procedure: Locked Uterine Closure<br>* The first layer of the two-layer uterine closure will be sutured with a running & locking technique. The second layer can be locking or non-locking.<br>|
| Experimental: Non-Locking Uterine Closure<br>Participants will undergo two-layer closure of the hysterotomy site at the time of cesarean section. The first layer will use a running & non-locking technique. The second layer will be performed based on surgeon preference, but cannot be of a locking technique. | Procedure: Non-Locking Uterine Closure<br>* The first layer of the two-layer uterine closure will be sutured with a running & non-locking technique. The second layer cannot be of a locking technique.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants Enrolled | Number of potential participants approached who actually enrolled in the trial | 6 months | 
| Number of Participants that Cross-Over | Number of participants who cross-over to the other study arm (i.e. who receive the incorrect uterine closure technique) | 6 months | 
| Number of Participants Lost to Follow Up | Number of participants enrolled in the trial who do not present for their follow up ultrasound at 6 months. | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of Isthmocele | The presence of an isthmocele (minimum 2 mm x 2 mm) identified on a transvaginal ultrasound 6 months after the cesarean section | 6 months | 
| Estimated Blood Loss | Number of mL of blood lost at the time of cesarean section | Through surgery completion (estimated 1 hour) | 
| Change in Hemoglobin | Change in Hgb from pre-operative measurement to Hgb measurement on post-operative day #1 | 24 hours | 
| Operative Time | Length of surgery (minutes) | Through surgery completion (estimated 1 hour) | 
| Number of Blood Transfusions | Number of intraoperative and post-operative blood transfusions given to each participant | Throughout hospital stay (estimated 48 hours) | 
| Additional Hemostatic Sutures | Number of additional hemostatic sutures placed in the uterus for each participant | Start to end of surgery | 
| Suture Material | Type of suture material used for hysterotomy closure | 6 months | 
| Use of Additional Oxytocin in Units | Number of units of additional oxytocin given to each participant as a uterotonic agent (beyond usual dose of intraoperative oxytocin) | Throughout hospital stay (estimated 48 hours) | 
| Use of Ergotamine in mg | Number of mg Ergotamine used as a uterotonic agent, if required | Throughout hospital stay (estimated 48 hours) | 
| Use of Hemabate in mg | Number of mg Ergotamine used as a uterotonic agent, if required | Throughout hospital stay (estimated 48 hours) | 
| Use of Misoprostol in mcg | Number of mcg Misoprostol used as a uterotonic agent, if required | Throughout hospital stay (estimated 48 hours) |