Comparison of Oblique Subcostal, Posterior or Dual Transversus Abdominis Plane Block in Laparoscopic Cholecystectomy
Comparison of Oblique Subcostal, Posterior or Dual Transversus Abdominis Plane Block in Laparoscopic Cholecystectomy
The aim of the study is to evaluate the difference of postoperative analgesic effects and
 opioid consumption between ultrasound-guided unilateral oblique subcostal, posterior, or dual
 TAP blocks in patients undergoing laparoscopic cholecystectomy for cholelithiasis.
Laparoscopic cholecystectomy is one of the most frequent operations. Laparoscopic
 cholecystectomy is a less invasive technic that provides early mobilization and reduces
 hospitalization time thus preferred to laparotomy often. There is a minimum of 4 trochar
 incisions on the right side of the abdomen at epigastric, umbilical, midclavicular subcostal,
 and anterior axillary subcostal regions in laparoscopic cholecystectomy. Some patients have a
 drainage tube at the middle/lower right abdomen. Thus the right side of the abdomen is the
 target side for abdominal wall blocks.

 Most patients complain of moderate pain after surgery which requiring opioids, mostly in the
 upper abdomen, lower abdomen, and shoulder. The pain has three components; somatic pain at
 the anterior abdominal wall, visceral pain caused by pneumoperitoneum and referred shoulder
 pain. Preventing postoperative pain is important for reducing respiratory complications and
 hospitalization time also improve patient satisfaction. Opioids are preferred less due to
 their side effects like nausea-vomiting and respiratory depression although which is
 preferable for moderate and severe pain. Transversus abdominis plane (TAP) block is the most
 preferred abdominal wall block to provide effective postoperative pain control for reducing
 perioperative analgesic requirements like opioids.

 TAP block was first described by Rafi by anatomic landmark technic then by Hebbard with
 ultrasonographic guidance. TAP block is a regional technic and a plan block that blocks the
 thoracolumbar nerves that innervate the anterior and lateral abdominal wall and passes in
 between the muscles' internal oblique and transversus abdominis. External oblique, internal
 oblique, and transversus abdominis muscles are displayed sequentially by ultrasonography. A
 hypoechoic, spindle-shaped separation of the fascia by hydrodissection technic is performed
 by local anesthetic injection in between the internal oblique muscle (or rectus abdominis)
 and transversus abdominis muscle. Dermatomal spread is differentiated with subcostal, oblique
 subcostal, and posterior approaches.

 In oblique subcostal TAP block, anesthetic solution spreads across the location of T6-L1
 nerves thus suitable for surgeries at both superior and inferior the umbilicus. Some other
 studies show that posterior TAP block can block the T5 to L1 thoracolumbar nerves thereby
 spreading into paravertebral space. The paravertebral spread of the posterior TAP block
 suggests that the analgesic efficacy will be long-lasting by blocking the thoracolumbar
 sympathetic chain and will spread to a wider dermatomal area. In this study, the
 investigators aimed to compare the analgesic efficacy and opioid-sparing effects of oblique
 subcostal, posterior, and dual TAP blocks in patients undergoing laparoscopic
 cholecystectomy. Taking the advantage of the paravertebral extension of the posterior
 approach and the wide spread of the oblique subcostal approach on the anterior abdominal
 wall, it's supposed to be the dual TAP block will result in lower pain scores.

 All patients will have general anesthesia. For premedication midazolam 0.03mg/kg will be used
 for all patients. At the induction of the anesthesia, patients will receive propofol 2 mg/
 kg, fentanyl 2 μg/kg, and rocuronium 0.6 mg/ kg IV. After enough muscle relaxation patients
 will be orotracheally intubated. General anesthesia will be maintained with sevoflurane and
 air/O2 mixture. The end-tidal carbon dioxide partial pressure will be maintained between 32
 and 36 mmHg by adjusting the pressure-controlled mechanical ventilation. All patients will
 receive tramadol 1mg/kg, paracetamol 1gr, and ondansetron 8mg intravenously before skin
 closure. Postoperatively ultrasound-guided right oblique subcostal and posterior TAP blocks
 will be performed on all patients. Postoperatively starting from at the postoperative care
 unit (0th hour) then 2nd,4th, 6th, 8th, 12th and 24th hours pain intensity by numerical
 rating scale (NRS) at rest and with motion, sensory dermatomal involvement by pinprick test,
 Ramsey sedation scales, nausea and vomiting scores, and rescue analgesic medication
 requirements will be recorded. Besides heart rate, blood pressure, respiratory rate,
 peripheric oxygen saturation, mobilization time, side effects if there are any will be
 recorded at the aforementioned hours. Patients with NRS≥4 will receive dexketoprofen 50mg as
 rescue analgesic medication. If NRS≥7 tramadol 100mg will be administered.

 The study will start after getting written informed consent from patients who are informed
 about the study and potential risks. The study is a prospective, clinical, randomized
 controlled, quadruple-blinded, and monocenter study. Participation of the 60 patients
 undergoing laparoscopic cholecystectomy had been planned. Patients will be randomized into
 three groups of 20 patients each.
Inclusion Criteria:

 -  Patients undergoing elective laparoscopic cholecystectomy for cholelithiasis

 -  ASA (American Society of Anesthesiologists) I-II

 Exclusion Criteria:

 -  Patient refusal

 -  Perforation of the gallbladder

 -  Patients with acute cholecystitis

 -  History of the previous gallbladder surgery

 -  Pregnancy

 -  Morbid obesity

 -  Psychiatric disorder

 -  Epilepsia

 -  Renal insufficiency

 -  Coagulopathy

 -  Patients known allergic to drugs used for study