A Trial Comparing Surgeon-administered TAP Block With Placebo After Midline Laparotomy in Gynecologic Oncology

Study Overview
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Brief Summary
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Multimodal opioid-sparing analgesia is recommended in order to prevent post-operative complications and shorten length of stay. Administration by the surgeon of local anesthetics in the abdominal wall after surgery for a suspected gynaecological malignancy will be studied. Eighty women above the age of 18 and undergoing a midline laparotomy for a suspected gynecologic malignancy will be recruited. Half of these women will received a Transversus Abdominis Plane (TAP) block using local anesthetics, and half will receive a placebo (saline water). The primary outcome studied will be the total dose of opioid in morphine equivalents received in the postoperative period. The primary hypothesis is that surgeon-performed TAP blocks reduce the need for opioids after surgery. Secondary outcomes including postoperative pain scores, postoperative nausea and vomiting rates, time to flatus, incidence of clinical ileus and time to discharge from hospital will also be recorded.

Detailed Description
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Multimodal opioid-sparing analgesia is recommended in order to prevent post-operative complications and shorten length of stay. While ultrasound-guided Transversus Abdominis Plane (TAP) block has been shown to reduce postoperative opioid use, the time and expertise needed to perform it can be a barrier to administering the procedure. A surgeon-administered TAP block has been described, but has yet to be evaluated with a randomized controlled study in gynecology oncology patients undergoing a midline laparotomy. The investigators hypothesize that surgeon-administered TAP blocks may decrease total opioid use in the first 24 hours. Eighty women above the age of 18 and undergoing a midline laparotomy for a suspected gynecologic malignancy will be recruited to undergo bilateral surgeon-administered TAP blocks with either 40ml of 0.25% bupivacaine or an equal volume of saline administered equally over both sides, prior to fascial closure. Exclusion criteria include inability to give informed consent, presence of contraindications or sensitivities to drugs specified in the protocol, pre-existing truncal sensory disturbance, history of chronic opioid use, infections at the injection site, significant adhesions on the anterior or lateral abdominal wall preventing access to the injection site, patients receiving neuraxial anesthesia (Epidural, Spinal) or local wound infiltration. The primary outcome studied will be the total dose of opioid in morphine equivalents received in the postoperative period. Secondary outcomes including postoperative pain scores, postoperative nausea and vomiting rates, time to flatus, incidence of clinical ileus and time to discharge from hospital will also be recorded. Sample size calculation was based on a meta-analysis by Johns for use of TAP blocks in abdominal surgeries, that reported morphine equivalents mean at 24h as 20.6mg for the TAP group and 44.3mg for the control group (mean difference of 23mg in 24h), with a standard deviation of 14mg. To find a clinically significant decrease in opioid use of 20%, our primary outcome, with a 2-tailed analysis and power of 80%; the investigators would need 36 patients in each group. To account for potential dropouts and protocol violations, as well as secondary analyses, the investigators will recruit a total of 80 patients (40 in the TAP block group and 40 controls). Differences in characteristics between treatment and control groups will be analysed using the chi-square test for dichotomous data, independent samples Student's t-test for parametric continuous variables, and Mann-Whitney U test for non-parametric continuous data. Test of normality will be performed using the Shapiro-Wilk test. If there is significant (>10%) missing data, data will be imputed by predictive mean matching. Subgroup analysis by type of incision (infraumbilical vs supraumbilical) will be performed. Missing data and patterns will be assessed monthly by the data manager. Remedial measures, including retraining of staff, will be used as needed to minimize missing data. The investigators plan for an intention-to-treat analysis.

Official Title
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A Double-blinded Randomized Trial Comparing Surgeon-administered Transversus Abdominis Plane (TAP) Block With Placebo After Midline Laparotomy in Gynecologic Oncology

Conditions
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Genital Neoplasm Malignant Female, Surgical Procedure, Unspecified

Intervention / Treatment
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* Procedure: Surgeon-administered transversus abdominis plane (TAP)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 18 and above undergoing elective gynecologic oncology surgery for a suspected malignancy using a midline laparotomy incision. Exclusion Criteria: Patients unable to give informed consent Patients with contraindications or sensitivities to drugs specified in the protocol Pre-existing truncal sensory disturbance History of chronic opioid use (daily use > 3 months) Infections at the injection site Significant adhesions on the anterior abdominal wall preventing access to the injection site Concurrent, non-abdominal surgical procedure performed at the same time Patients receiving neuraxial anesthesia/analgesia (epidural, spinal) or local wound infiltration

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Eighty women above the age of 18 and undergoing a midline laparotomy for a suspected gynecologic malignancy will be randomized to undergo a bilateral surgeon-administered Tranversus abdomens plane block with either 40ml of 0.25% bupivacaine or an equal volume of saline administered equally over both sides (placebo), prior to fascial closure. Forty patient will receive bupivacaine, and 40 patients will receive the placebo.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bupivacaine<br>Administration of 20ml of bupivacaine 0.25% on each side, for a total of 40ml. | Procedure: Surgeon-administered transversus abdominis plane (TAP)<br>* Prior to fascial closure, the rectus muscle is gently elevated superiorly and the surgeon identifies its lateral border; the nerves that supply the anterior abdominal wall travel through the myofascial plane between internal oblique and transversus abdominis muscles, 2 fingerbreadths above the iliac crest. Access to this plane can easily be achieved by inserting a blunted needle through the parietal peritoneum; there is an appreciable loss of resistance ('one pop') and the correct plane is entered. After careful aspiration to ensure no vascular injury has occurred, 20 mL 0.25% bupivacaine or 20 mL of normal saline is injected slowly. The same procedure is repeated on the other side.<br>|
| Placebo Comparator: Saline<br>Administration on 20ml of normal saline on each side, for a total of 40ml. | Procedure: Surgeon-administered transversus abdominis plane (TAP)<br>* Prior to fascial closure, the rectus muscle is gently elevated superiorly and the surgeon identifies its lateral border; the nerves that supply the anterior abdominal wall travel through the myofascial plane between internal oblique and transversus abdominis muscles, 2 fingerbreadths above the iliac crest. Access to this plane can easily be achieved by inserting a blunted needle through the parietal peritoneum; there is an appreciable loss of resistance ('one pop') and the correct plane is entered. After careful aspiration to ensure no vascular injury has occurred, 20 mL 0.25% bupivacaine or 20 mL of normal saline is injected slowly. The same procedure is repeated on the other side.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total dose of opioid (in morphine equivalents) received in the postoperative period |  | 24 hours after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative pain scores | Numerical Pain Rating Scale, from 0 to 10. The scale is composed of 0 (no pain at all) to 10 (worst imaginable pain). | at 4, 8, 12, 16, 20, 24, 30, 36, 42 and 48 hours after surgery | 
| Postoperative nausea and vomiting rates | As defined by the Simplified Postoperative Nausea and Vomiting (PONV) impact scale | postoperative day 1 | 
| Time to flatus | In hours | During admission | 
| Incidence of clinical ileus | as a surgeon's diagnosis of postoperative ileum, including diagnosis on abdominal x-ray, return to nothing-by-mouth status, or (re)insertion of a nasogastric tube. | During admission | 
| Time to discharge from hospital | In hours | During admission | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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randomized controlled trial, Transversus Abdominis Plane block