To estimate the efficacy of the ultrasound guided ESP block for postoperative pain control in open knee surgeries under general anesthesia.

Postoperative pain is a major concern after knee surgeries. It is severe in 60% of patients and moderate in 30%. When inadequately treated, it intensifies reflex responses, which leads to cause serious complications, such as cardiovascular, pulmonary or urinary problems, thromboembolism, increased oxygen consumption, hyperdynamic circulation and hinders early physical therapy. Generally it has been assumed that adequate postoperative pain relief may reduce these complications, and improve general postoperative outcome.

In the last decade Improvements in pain management techniques have had a major impact on the practice of knee surgeries. Although there are a number of treatment options for postoperative pain, a gold standard has not been established. Patient-controlled analgesia (PCA), epi¬dural analgesia and lumbar plexus and/or sciatic blocks are the commonly used routes for pain relief after joint surgery .Each of those options has advantages and disadvantages. PCA has fewer technical problems, uniform and sustained analgesia with autonomy, however it might lead to respiratory depression, nausea and vomiting. Epidural analgesia is an efficient route for postoperative analgesia ; however it is associated with technical failures, hypotension, urinary retention, and ileus, motor block that limits ambulation, unrecognized compartment syndromes, and spinal hematoma secondary to anticoagulation.

The ultrasound-guided erector spinae plane (ESP) block is a recently described regional anesthetic technique for providing thoracic analgesia when performed at the level of T5 transverse process. Local anesthetic is injected into the fascial plane deep to the erector spinae muscle, and spreads craniocaudally over several levels can lead to effective analgesia and sensory block from T2 to T9. Local anesthetic also penetrates anteriorly through the intertransverse connective tissue and enters the thoracic paravertebral space where it can potentially block not only the ventral and dorsal rami of spinal nerves but also the rami communicantes that transmit sympathetic fibers.

ESP advantages include its simplicity, easy identifiable ultrasonographic landmarks and an endpoint for injection and low risk for serious complications as injection is into tissue plane that is distant from pleura, major blood vessels and discrete nerves.

There is clinical report of two cases shows the ESP block may be a safe, simple and effective technique for analgesia following surgery around the knee.

However, confirmation of the efficacy of ESP block in knee surgeries needs more investigation.

Inclusion Criteria:

• • Patients aged from 18 to 60 years old.

  • Genders eligible for study: both sexes.
  • ASA I-II.
  • Undergo knee surgery.
  • BMI from 18 to 35 kg/m2.

Exclusion Criteria:

• • Patient refusal.

  • Patients with difficulty in evaluating their level of pain.
  • Contraindications to regional anesthesia (Bleeding disorders e.g. INR>1.5, PC<70%, platelet count<100 × 109, Use of any anti-coagulants, local infection, etc.).
  • Known allergy to local anesthetics.