SOFT Block Versus Spinal Anesthesia in Patients Undergoing Surgery for Fixation of Open Tibial Fractures Using Ilizarov External Fixator

After the approval of medical ethical committee of Ain Shams University, this prospective parallel group double blinded study will be conducted over 60 patients between the age of 35-57 years old, ASA physical status I and II, scheduled for fixation of open tibial fractures using iIlizarov external fixator. at Ain Shams University hospitals in 2018-2019, After written informed consent is obtained.

Refusal to participate, inability to communicate with the investigators or hospital staff, obesity (body mass index>40 kg/m2), patients undergoing bilateral surgery, patients with coagulopathies ,renal insufficiency (creatinine>1.5 mg/dL), American Society of Anesthesia (ASA) III-IV, patients with any contraindication to regional anesthesia , patients with unstable vital data and patients with head or chest trauma will be excluded.

Preanesthetic check will be done at night of surgery. After an intravenous (IV) cannula will be secured , and midazolam 0.05 mg/kg i.v. will be given to all patients before transfer to the operating room where standard monitoring devices as ECG,Non invasive blood pressure and pulse oximetry will be placed. Then, patients will be randomly allocated by sealed envelope technique to receive either spinal anesthesia or SOFT block. In spinal anesthesia group, patients will receive spinal anesthesia with hyperbaric bupivacaine 0.5% (7.5-10mg). This will be administered via a 25-G spinal needle at L4-L5 or L3-L4 with the patient in the sitting position under complete aseptic conditions.

In SOFT group, patients will receive SOFT block where patients will be positioned in supine position,under aseptic conditions, a linear US probe will be placed on the inguinal crease to show the femoral nerve and vessels. Using an in-plane technique, a 12-cm stimulating block needle will be introduced medial to the femoral vein and advanced 1-3 cm below and parallel to the skin. Then, It will be redirected toward the fibres of the femoral nerve, where 15 mL of bupivacaine 0.25% will be injected. To block the obturator nerve, the probe will be shifted medially, superior to the needle, and directed cranially to identify the pectineus muscle . The needle will be then withdrawn to the subcutaneous tissue and redirected using an out-of-plane technique toward the deep surface of the pectineus, where 10 mL of bupivacaine 0.25%will be injected.[4 ] To locate the sciatic nerve, we will use the curvilinear probe, directed it inferior to the needle, and tilted the probe to get the clearest image of the sciatic nerve.The needle will be inserted then withdrawn subcutaneously and directed by an in-plane technique toward the sciatic nerve deep to the inferior border of the quadratus femoris muscle. Then 20 mL of bupivacaine 0.25% will be injected after needle elicited muscle twitches using 1 mA current.

Sensory level will be evaluated by loss of pinprick sensation (20-gauge hypodermic needle).