Spinal anesthesia is a commonly employed technique for lower abdominal surgeries, providing effective anesthesia and analgesia with minimal systemic effects. In cancer patients undergoing such procedures, careful consideration of anesthetic techniques is crucial, given their often-compromised physiological state and the need to minimize postoperative complications. Two approaches to administering spinal anesthesia are Ultrasound (US)-guided and the traditional landmark-based technique.

the aim of the study :To evaluate the efficacy, safety and feasibility of US-guided spinal anesthesia versus the landmark-based technique in cancer patients undergoing lower abdominal surgery.

The traditional landmark method relies on palpating anatomical structures, such as the iliac crests and spinal processes, to guide needle insertion. Although widely used, it can be challenging in patients with anatomical variations, obesity, or previous surgeries, potentially leading to multiple attempts, increased patient discomfort, or complications. On the other hand, Ultrasound (US) imaging has become an increasingly popular tool among anesthesiologists to guide neuraxial blockade. US-guided spinal anesthesia provides real-time visualization of the relevant anatomy, including the spinal canal, ligaments, and surrounding tissues, enabling more accurate needle placement. This technique has gained attention for its potential to improve success rates, reduce complications, and enhance patient comfort, particularly in complex cases such as cancer patients, where precision is vital.

By examining factors such as procedural success rates, patient comfort, complication rates, and overall outcomes, we can better understand the role of ultrasound guidance in optimizing anesthetic care for this vulnerable patient population.

Inclusion Criteria:

• Age >18 years old
• Both sex
• patients with a body mass index (BMI) of 18-40 kg/m2
• American Society of Anesthesiologists (ASA) physical status classification of I to III.

Exclusion Criteria:

• • Patients have a contraindication for regional anesthesia, e.g. coagulopathy.

  • Failed or unsatisfactory intrathecal block.
  • Patients with known hypersensitivity to amide local anesthetics.
  • Local injection site infection or spinal deformity.
  • Severe hypotension.
  • Space occupying lesions of the brain.
  • Hypovolemia.
  • Pregnancy.

Patients will be randomly assigned to receive spinal anesthesia using the surface landmark-guided (landmark group) or preprocedural ultrasound-assisted (ultrasound group) technique using a computer-generated table of random numbers. Group allocation will be concealed by sequentially numbered, sealed opaque envelopes, which are opened only by the attending anesthesiologist immediately before the procedure.