The objective of this study is to compare the postoperative analgesic effect of bupivacaine injection via ultrasound-guided erector spinae block versus transmuscular quadratus lumborum block in patients undergoing abdominal cancer surgery

Surgical trauma activates numerous receptors leading to severe postoperative pain. Therefore, effective pain management is a priority of care and a patient right .

Postoperative pain may cause tachycardia, hypertension, increased cardiac work, nausea, vomiting, ileus. Also if it is inadequately managed may lead to detrimental Cardiovascular effects, pulmonary dysfunction, immune system, neuro-endocrine and metabolic effects, gastrointestinal, urinary dysfunction, coagulation system , cognitive dysfunction and also have psychological, economic and social adverse effects Good postoperative analgesia can prevent morbidity associated with abdominal surgeries by allowing pain-free, early ambulation and decreasing the risks of long hospital stay, thromboembolism, and other poor outcomes.

Adequate pain treatment is an important component of modern perioperative care and essential for a fast recovery. Choosing the optimal analgesic modality remains a topic of debate especially in major abdominal surgeries.

Various techniques have been tried to replicate the analgesic efficacy of TEA. They include transversus abdominis plane analgesia (TAP), rectus sheath analgesia (RS), wound infusion analgesia (WI) and transmuscular quadratus lumborum (TQL) analgesia.

However each of these techniques has specific limitations that prevent them from being the analgesic technique of choice for all open abdominal surgeries.

The ultrasound (US)-guided erector spinae plane block (ESPB) was initially described by Forero et al.It as a relatively new technique, originally described to manage thoracic pain when performed at the T5 vertebra level, but it has also been successfully used for abdominal analgesia when performed at T7 level.

ESPB gained wide attention as it is a faster procedure that carries a lower risk of hypotension, can be used in patients with coagulopathy, easy to perform, and requires less training.

ESPB provides extensive, potent unilateral analgesia, performed by local anesthetic injection in the plane between the erector spinae muscle and the TP. The local anesthetic diffuses into the paravertebral space through spaces between adjacent vertebrae and blocks both the dorsal and ventral rami of the thoracic spinal nerves.

Bilateral ESPB performed at low thoracic levels provides satisfactory analgesia for abdominal surgeries in case reports and series describing abdominal exploration, cesarean section, ventral hernia repair, and abdominoplasty.

As LA widely spreads cranially and caudally when ESPB is performed, we think that ESPB can effectively be used as an analgesic method for abdominal surgeries.

The ultrasound-guided (USG) quadratus lumborum block QLB was first described by Rafael Blanco in a presentation at ESRA 2007 at the XXVI Annual ESRA Congress in Valencia, Spain. Blanco described a potential space posterior to the abdominal wall muscles and lateral to the quadratus lumborum muscle (QL) where Local anesthetics (LA) can be injected. This technique provides analgesia after abdominal surgeries due to spread of LA from its lumbar deposition cranially into the thoracic paravertebral space (TPVS) where lateral and anterior cutaneous branches from Th7 to L1 nerves can be blocked. This was proved later by Carney et al. who found traces of contrast agent in the TPVS following the block.

Quadratus lumborum block (QLB) under ultrasound has been one of the interfascial plane blocks being popularized in regional anesthesia over the last few years given the vast number of indications in a variety of abdomino-pelvic surgeries in pediatrics and adults. In clinical studies, it also has been shown to have opioid sparing effects and prolonged post-operative analgesia than more conventional procedures like TAP blocks.

Several approaches have been described for QLB. Lateral QLB (or QLB-1) where local anesthetic is injected at the anterolateral border of the QL muscle. Posterior QLB (or QLB-2) where LA is injected at the junction of QL muscle with the transversalis fascia., Another novel approach is the transmuscular QLB (or QLB-3), where the needle is advanced through the QL muscle, penetrating the ventral proper fascia of the QL muscle and LA is finally injected between the QL muscle and Psoas Major (PM) muscle. It is thought that this approach (QLB-3) does not result in redundant antero-lateral spread of the LA.

Inclusion Criteria:

1. Patients subjected to abdominal cancer surgery.
2. The enrolled age will be from 18 years to 70 years.
3. ASA I-II and NYHA I-II.

Exclusion Criteria:

1. ASA physical status >II, and NYHA >II.
2. Patient refusal.
3. body mass index >40 kg/m2.
4. preoperative opioid consumption.
5. a local infection at the incision site.
6. a history of hematological disorders or coagulation abnormality.
7. previous abdominal surgeries, severe hepatic or renal impairment
8. Anomalies of vertebral column.
9. Pregnant women.
10. Hypersensitivity to any of used drugs.
11. chronic pain.