Ultrasound imaging has revolutionized the practice of regional anesthesia in that the operator can visualize and identify the paravertebral space, needle during its passage through the tissues, as well as deposition and spread of local anesthetic into the desired spaces. The usage of ultrasound may facilitate more rapid block onset and prolong duration with the added advantage of decrease in drug dosage, reduction in incidence of local anesthetic toxicity, increase success rate, reduction in procedure pain and better patient satisfaction.

Paravertebral block targets drug delivery to the site of pain, thus decreasing opioids use. It can provide greater overall comfort with lower pain scores and greater tolerance of physical activity during the initial postoperative period.

Ultrasound imaging has revolutionized the practice of regional anesthesia in that the operator can visualize and identify the paravertebral space, needle during its passage through the tissues, as well as deposition and spread of local anesthetic into the desired spaces. The usage of ultrasound may facilitate more rapid block onset and prolong duration with the added advantage of decrease in drug dosage, reduction in incidence of local anesthetic toxicity, increase success rate, reduction in procedure pain and better patient satisfaction.

To the best of researchers' knowledge, evaluation of unilateral ultrasound guided paravertebral block as perioperative analgesia for lower limb-sparing surgery in adult cancer patients was not investigated before.

Inclusion Criteria:

1. Physical status ASA II and III.
2. Age ≥ 18 and ≤ 65 Years.
3. Body mass index (BMI): > 20 kg/m2 and < 40 kg/m2.
4. Patient undergoing lower limb-sparing surgery for cancer surgeries under general anesthesia.

Exclusion Criteria:

1. Patient refusal.
2. Known sensitivity or contraindication to local anesthetics.
3. History of psychological disorders and/or chronic pain.
4. Coagulopathies with INR ≥1.5: hereditary (e.g. hemophilia, fibrinogen abnormalities & deficiency of factor II) - acquired (e.g. impaired liver functions with PC less than 60 %, vitamin K deficiency & therapeutic anticoagulants drugs).
5. Significant liver or renal insufficiency.
6. Localized infection at the site of block.

Until ending the investigator's work

sealed opaque envelopes prepared by an assistant blinded about the study targets and chosen by patient him/herself, allocated into two groups