Breast reconstruction using a patient's own abdominal tissue is one of the most common methods for restoring mastectomy defects for breast cancer patients. Despite its increasing popularity and safety, the abdomen remains a major source of postoperative pain. Adequate pain control is important as it has been shown to reduce medical complications, in-hospital death, shortens hospital stay, lessen chronic pain and disability, and in turn lower health-care costs. The current postoperative pain relief protocol consists primarily of a patient-controlled anesthesia device delivering intravenous opioids. Opioids can cause numerous side-effects such as sedation, headache, nausea, vomiting, breathing difficulties, bladder and bowel dysfunction. A promising approach to provide postoperative pain control of the abdominal incision is the newly developed transversus abdominis plane (TAP) peripheral nerve block. Although the TAP block has been found to be an effective pain-relief following major abdominal surgeries, its use has never been studied for breast reconstruction using abdominal tissue. Therefore, the investigators propose to rigorously study the efficacy of a TAP block in reducing postoperative abdominal pain following abdominal tissue breast reconstruction. This study has significant implications in improving both clinical care and health outcomes in patients undergoing this common method of breast reconstruction technique.

1. Statement of Objectives/Specific Aims

The transversus abdominis plane (TAP) block is a newly developed block involving T6-L1 nerves that supply the anterior abdominal wall. Its effectiveness has been reported following major abdominal surgeries, but not following abdominally-based autologous tissue breast reconstruction. Thus, we propose a randomized, double-blind, placebo-controlled trial to evaluate the efficacy of TAP block in improving pain symptomatology following abdominally-based, autologous tissue breast reconstruction.

The primary objective of this study is to compare the mean total opioid consumption in the first postoperative 48 hours between the control and study groups in intravenous morphine equivalent units. By directly blocking the neural afferents, the mean opioid consumption will be significantly lower in the group receiving intermittent local anaesthetic boluses compared to the placebo group through a TAP catheter.

The secondary outcomes of interest are to compare the following parameters:

A. Continuous outcomes i. Total in-hospital cumulative opioid consumption ii. Total in-hospital cumulative anti-nausea consumption iii. Quality of Recovery (QOR) score (0-18) iv. Duration of hospital stay

B. Repeated measures outcomes

In Hospital postoperative measures:

i. Daily pain intensity scores at rest and with movement using a visual pain analogue scale (0-10) ii. Postoperative nausea and vomiting (score of 0-3) iii. Sedation score

Long-term chronic pain, anxiety, function, and quality of life (QOL) measures:

iv. Pain disability index v. Short-form McGill Pain Questionnaire vi. Hospital Anxiety and Depression Scale vii. Short-form 36

C. Time to event outcomes i. Time to first bowel movement ii. Time to ambulation

Hypothesis: Compared to the control group, the TAP block group will have a statistically significant reduction in total in-hospital consumption of opioids, pain scores and side-effects from opioid use such as sedation, nausea, and vomiting. This should also result in a greater QOR score in the TAP block group. Surgical milestones such as time to ambulation, first bowel movement, and duration of hospital stay will also be reduced in the TAP block group. In addition, we hypothesize less acute postoperative pain achieved using the TAP block will result in a reduction in chronic pain and disability, anxiety and depression, and improved QOL in the long-term.

Inclusion Criteria:

-Pre-operative eligibility:

• Patients above the age of 18, no upper age limit
• English-speaking
• Delayed reconstruction (mastectomy already performed) or immediate reconstruction (mastectomy at the same time as reconstruction)
• Reconstruction using abdominal tissues including free MS-TRAM or DIEP

Exclusion Criteria:

• Patient refusal

• Inability to give informed consent

• BMI > 40

• Allergy to Bupivacaine

• Known cardiac or liver disease (contraindicated for Bupivacaine use)

• Patients who will undergo any of the following:

  • Implant breast reconstruction
  • Combined implant and autologous tissue reconstruction
  • Non-abdominally based autologous tissue reconstruction
  • Nonmicrosurgical abdominally based breast reconstruction (pedicled TRAM flap)

• Drug addiction

• Opioid tolerance defined as preoperative opioid use of >50 mg PO morphine equivalent

• Psychiatric illness

The study limitations include the difficulty in capturing data at all points postoperatively. The repeated measure pain scores at rest and with movement were not recorded for all patients (recorded for 75% at rest and 53% with movement).