Open nephrectomy is associated with substantial postoperative pain, pain relief in patients undergoing this procedure is usually provided either by thoracic epidural analgesia (EA) or systemic analgesics. EA is a very useful option for the management of postoperative pain in patients undergoing abdominal surgeries, but the risks and contraindications linked to EA like hypotension ,headache ,nerve damage or infection may limit its use. Systemic analgesics in the form of opioid analgesics may give rise to side effects like nausea ,vomiting ,constipation, allergy or drowsiness and often provide insufficient analgesia. Hence, other methods of postoperative pain management are desired. Sensory level target according to the incision site Flank(T9-T11) , Thoraco-abdominal (T7-T12 ) and Trans-abdominal (T6-T10).~Ultrasound (US) guided erector spinae plane (ESP) block is one of the interfascial plane blocks that target the dorsal and ventral rami of the spinal nerves. Although there is no sufficient evidence for the spread of local anesthetic to the ventral rami, recent anecdotal reports demonstrated effective postoperative analgesia after thoracic and lumbar surgeries affecting both the ventral and dorsal rami .According to a previous study, Erector Spinae Plane block has allowed a reduction in opioid consumption and excellent pain control in partial nephrectomy.~Paravertebral block (PVB) is a technique where a local anesthetic is deposited into a space found on both sides of the spine, called the paravertebral space. It is a block with a dermatomal distribution of pain relief depending on the level of the spine at which the block is sited and the quantity and type of deposited local anesthetic.~PVB is effective for pain relief in the thoracic, abdominal and limb regions .
the study aims to compare the analgesic efficacy of erector spinae plane block versus thoracic paravertebral block after open nephrectomy surgery.