The study is to evaluate effectiveness of one-level versus two-level thoracic ESP block on intraoperative and postoperative analgesia in bariatric surgeries and to compare total opioid consumption of both groups.

The prevalence of overweight and obesity is steadily increasing. The epidemic of overweight and obesity presents a major challenge to chronic disease prevention and health across the life course around the world.

Bariatric surgery has proved to be an efficient intervention in the management of obesity. As a result, the number of post-bariatric surgery patients in the population is growing .

Postoperative pain is categorized into acute pain which occur immediately after surgery (up to 7 days) and chronic pain which lasts more than 3 months after the injury . Laparoscopic bariatric surgery often presents significant pain, ranging from moderate to severe, particularly in the immediate time following the operation, it is estimated that 75% of patients experience moderate pain post laparoscopic bariatric surgeries .

Postoperative pain is divided into four types according to cause, Nociceptive Pain is the signal of tissue irritation, impending injury, or actual injury. Neuropathic Pain is the result of the nervous system injury or malfunction, either in the peripheral or in the central nervous system, Psychogenic Pain due to the psychological factors leading to an exaggerated or histrionic presentation of the pain problem, Mixed Category Pain is caused by a complex mixture of nociceptive and neuropathic factors .

Due to the higher risk of respiratory depression, administering opioids to morbidly obese individuals might provide significant challenges when it comes to delivering pain relief .

Acetaminophen is widely considered the cornerstone of perioperative analgesia in the general surgical population.it has been supported by studies and experience in bariatric centers .

Non-steroidal anti-inflammatory drugs (NSAIDs) are components of foundational analgesia for nociceptive pain, which contribute to additional excellent opioid-sparing analgesia. The well-known perioperative concerns with NSAIDs (nephrotoxicity, gastrointestinal (GI) ulceration, and increased bleeding risk) are less likely with cyclooxygenase-2 (COX-2) inhibitors .

Perioperative tramadol side effects in the bariatric surgical population include increased postoperative nausea and vomiting (PONV), serotonin syndrome-inducing interactions (with anti-depressants), and more non-specific intolerance. Despite these, tramadol has been found useful in postoperative pain management after bariatric surgery.

The erector spinae plane block (ESPB) is a kind of paraspinal fascial plane block, which was initially described by Forero et al., (2016). The administration of local anesthetic (LA) occurs in the space between the thoracic transverse processes and the erector spinae muscle. This technique blocks the dorsal and ventral rami of the thoracic and abdominal spinal nerves, resulting in both somatic and visceral sensory blockade. This can potentially provide effective pain relief after abdominal surgery.

ESPB is effective, easy to perform, and can be performed in short time.(13) BUT there is no clear consensus in the studies conducted to determine the optimal level that can be achieved with volume expansion.

Previous reports have mentioned the analgesic effectiveness of one level ESPB in bariatric surgery, but this is the first randomized clinical trial to evaluate the feasibility, efficacy, and safety of two-level bilateral Erector Spinae Plane Block compared to one level in bariatric surgeries.

Inclusion Criteria:

• Patient age ranges 18 to 60 years old
• Obese patients ; Body mass index(BMI) ≥ 35 - 50 kg/m2
• American Society of Anesthesiologists (13) physical status classes II to III
• Patients scheduled for laparoscopic bariatric surgery i.e. sleeve gastrectomy and/or Roux-en-Y gastric bypass (RYGB) surgeries

Exclusion Criteria:

• • Refusal of regional block

  • Patients with neurological, psychological disorders or those lacking cooperation.
  • Patients scheduled for concomitant laparoscopic cholecystectomy or paraumbilical hernia repair or those with history of previous bariatric surgery or obstructive sleep apnea.
  • Patients with anatomic abnormalities at site of injection, skin lesions or wounds at site of proposed needle insertion.
  • Patients with bleeding disorders defined as (INR >1.4) and/ or (platelet count <100,000/µL)
  • Patients with hepatic disease e.g. liver cell failure or hepatic malignancy or hepatic enlargement.
  • Patients who are allergic to amide local anesthetics

included Patient age will range 18 to 60 years, Body mass index(BMI) ≥ 35 - 50 kg/m2, American Society of Anesthesiologists physical status classes II to III, scheduled for laparoscopic bariatric surgery i.e. sleeve gastrectomy and/or Roux-en-Y gastric bypass (RYGB) surgeries, with normal coagulation profile, npt allergic to amide