Bilateral Bi-level Erector Spine Plane Block as a Component of General Anesthesia in Surgical Correction of Spinal Deformations

The study will involve patients for whom are indicated a surgical correction of spinal deformations.

The control group will include patients who will undergo surgery under general anesthesia. The study group will include patients who will undergo surgery under general anesthesia using a bilateral bi-level Erector spine plane block.

Stages of the study: preoperative period, onset of anesthesia (induction of anesthesia), maintenance of anesthesia, end of anesthesia, 6th and 12th hours after surgery, 1st, 3rd, 5th day after surgery.

All patients will be given the same preparation for surgery: 5-7 days before the procedure - erythropoietin (50-75 IU / kg) subcutaneously once; iron 100 mg iv daily; thiamine hydrochloride (50 mg), pyridoxine hydrochloride (50 mg), cyanocobalamin (0.5 mg) and ascorbic acid (500 mg) orally, daily. The condition of the cardiovascular and respiratory systems will be assessed by auscultation and percussion of the heart and lungs, the results of electrocardiography, echocardiography, spirometry will by also estimate, vascular Doppler of the lower extremities and neck will by also performed.

Blood tests will be taken before and after surgery (haemoglobin, erythrocytes, leukocytes, colour index, haematocrit, leukocyte formula, erythrocyte sedimentation rate, blood glucose, coagulogram, electrolytes, creatinine, urea, albumin, bilirubin, transaminases, cortisol, testosterone, c-reactive protein).

Patients will be given recommendations on proper nutrition before surgery (solid food is allowed 6 hours before surgery and 150 ml of sweet clear liquid 2 hours before surgery), hospitalization will take place on the day of surgery.

All patients will have two peripheral veins cannulated and a urethral catheter will be installed before surgery. In patients with scoliotic spinal deformity, a central venous catheter will be inserted into the right jugular vein under ultrasound guidance prior to surgery. Antibiotic prophylaxis will be performed two hours before the skin incision. Mechanical bowel preparation and premedication with sedatives will not be performed.

All patients in the operating room will receive paracetamol, dexketoprofen, ondansetron, diphenhydramine, dexamethasone, atropine, tranexamic acid. For induction of anesthesia - propofol, thiopental, fentanyl, atracurium besylate, suxamethonium iodide. After preoxygenation - intubation of the trachea in an improved position and further rotation on the abdomen with specific placement of the patient to prevent compression of the abdominal cavity. In patients with scoliotic spinal deformity in the abdominal position will be used a lung recruitment manoeuvre (gradual increasing in positive end-expiratory pressure and inspiratory pressure with assessment of tidal volume and lung pliability), and subsequent protective ventilation and supporting Driving Pressure 12-14 cm H2O.

The operation will be performed under general inhalation anesthesia with sevoflurane and dexmedetomidine infusion. In patients undergoing neuromonitoring, relaxants will be administered only for tracheal intubation.

Intraoperatively, all patients will be monitored for electrocardiography, respiratory rate, body temperature, systolic, diastolic and mean blood pressure, heart rate, pulse oximetry.

During the operation, an assessment of blood loss and subsequent balanced infusion therapy will be performed. The volume and rate of urination will be assessed. A constant infusion of tranexamic acid will be established. Controlled arterial hypotension with mean blood pressure of at least 60 mm Hg will be maintained. To protect the spinal cord and its roots from ischemic injury during the derotation maneuver, mean blood pressure will be maintained at normal or elevated levels.

Correction of blood loss will be carried out with balanced solutions of crystalloids. Blood transfusion will be started at Hb less than 90 g / l. Patients will be warmed by the Warm Touch heating system. All patients will be extubated in the early postoperative period.

For the purpose of analgesia in the postoperative period, patients of both groups will receive paracetamol and dexketoprofen, thromboprophylaxis will be performed depending on the risk of thromboembolic complications.

In the study group, after intubation of the trachea and rotation on the abdomen before the skin incision will be performed bilateral bi-level Erector spine plane block. Before surgery, the level of screw placement will be discussed with the surgeon, and the blockade will be performed at two levels of the spine bilaterally as close as possible to the screw placement site. For blockade a solution for prolonged blockade of peripheral nerve plexuses with bupivacaine 0.375%, dexamethasone 0.02% and epinephrine 0.00018% will be used (Patent №133643 Ukraine 'Solution for prolonged blockade of peripheral nerve plexuses' inventor and owner Barsa Maksym № u201900272, declared 10.01.2019, valid from 10.04.2019, Bulletin № 7).

The total amount of solution administered is 40 ml (10 ml per injection). The erector spine muscle and the transverse process of the spine will be identified using a linear ultrasound probe at the required level of the spine 3cm laterally from the spinous process. Then, using an echogenic needle under ultrasound control in a space between the Erector spine muscle and the transverse process bilaterally on two levels of the spine a local anaesthetic with adjuvants will be injected (Patent №140510 Ukraine 'Method of anaesthesiologic securement for surgical correction of scoliosis spinal deformity' inventor and owner Barsa Marsym № u201911515, claimed 28.11.2019, valid from 25.02.2020, Bulletin № 4).