Comparison of Efficacy of Unilateral Transversus Abdominis Plane (TAP) Block Versus Bilateral Transversus Abdominis Plane (TAP) Block in Patients Undergoing Laparoscopic Cholecystectomy.

1. INTRODUCTION:

Laparoscopic cholecystectomy (LC) is the gold standard procedure for individuals with symptomatic gallstone disease. Although LC is a minimally invasive procedure with very less morbidity, early post-operative pain still a significant issue.1 Adequate pain control is therefore necessary to improve clinical outcomes, patient satisfaction and to ensure early mobility of the patients. Pain after laparoscopic cholecystectomy can be broadly classified into 3 categories: (a) somatic pain due to skin incisions; (b) Visceral pain due to intra-abdominal gallbladder dissection and; (c) reflected visceral pain or referred pain to the tip of right shoulder. Out of these, the somatic pain from port site incisions is the most troublesome for patients. Various methods have been tried to reduce post-operative pain after LC, one of which is the Transversus abdominis plane (TAP) block. TAP block is a regional anesthesia technique used for post-operative analgesia in abdominal surgeries. TAP block was first described by Rafi et al in 2001, as a regional block, in which local anesthesia is injected through triangle of petit to achieve analgesia of the T6 to L1 thoracolumbar nerves as they pass through the plane between internal oblique and transversus abdominis muscles.5,7,8 This blocks the sensory nerves in the anterolateral abdominal wall. Unilateral TAP block has been used as a part of multimodal analgesia in LC, with favorable results. However, half of the port site incisions in LC are located in the midline, i.e. the subxiphoid epigastric and the umblical ports. So, whether a unilateral TAP block alone provides adequate analgesia or not, cannot be stated as a fact. Although literature compares unilateral vs bilateral TAP in a variety of different surgical procedures, such as cesarean section and laparoscopic shockwave lithotripsy10,11 only one study is available to compare unilateral TAP versus bilateral TAP in LC.

Thus, the rationale of this study is that more research needs to be done to compare unilateral and bilateral TAP blocks in LC so as to establish which of the two is more efficient in providing adequate analgesia and eliminating the need for post-operative intravenous opioids. This will help us to better understand the role of in TAP block in LC. It is expected that this will help in reducing the need and dosage for postoperative IV opioids thus reducing post-operative nausea and vomiting (PONV), improve patient satisfaction and allow early mobilization of the patient. Mayo hospital Lahore is one of the largest government sector hospitals of Punjab with a dedicated surgical facility well equipped to deal with large numbers of patients with symptomatic gallstones. This makes this hospital an ideal set-up for conducting this research. 2. OBJECTIVE:

Primary objective of this study is to compare unilateral and bilateral TAP blocks in terms of efficacy in terms of mean duration of postoperative analgesia and the need and amount of post- operative IV opioids needed. Secondary objectives include comparison of both blocks in terms of PONV, the need and amount of ondensetron, and patient satisfaction. 3. OPERATIONAL DEFINITIONS:

1. TRANVERSUS ABDOMINIS PLANE (TAP) BLOCK: