Serratus Posterior Superior Intercostal Plane Block Versus Erector Spinae Plane Block in Thoracic Spine Surgeries

Spinal surgeries coincide with high level of pain due to extensive dissection and muscle retraction so inadequate pain control delays patient recovery, rehabilitation and also is an important source of patient dissatisfaction [1].

Non-steroidal anti-inflammatory drugs and opioids are used to control pain post spine surgeries. The side effects of opioids are nausea and vomiting (PONV), delirium, sedation, constipation, tolerance, respiratory depression, and high dependence [2]. Many efforts done by different studies to decrease the length of hospital stay and the dependence on opioids by using multimodal analgesic modalities including regional blocks by injection of local anesthesia before skin incision to block the pain pathway from the start. [3] The SPSM originates from C7-T2 (sometimes T3) spinous processes, progressing obliquely and inserting on the lateral of the second to fifth ribs' angle , The Serratus Posterior Superior Intercostal Plane Block (SPSIPB) first described by Tulgar et al,[4] is a novel interfascial plane block that involves the injection of a local anesthetic between the Serratus posterior superior and intercostal muscles, dermatomal analysis of the patients showed sensory block reached the C3 dermatome in all patients in the cephalic direction. In the caudal direction, it was determined that sensory block reached at least the T7 dermatome in all patients.

Erector spinae plane (ESP) block first described in 2016 by Forero et al. [5], it is a truncal block which inject (LA) between the thoracic transverse process and erector spinae muscle and spread to the thoracic paravertebral space thereby targeting the dorsal and ventral rami of spinal nerves [6]. Because they may provide an alternative to thoracic paravertebral blocks with fewer risks of pneumothorax, it is used to provide postoperative analgesia for thoracic and spine surgeries. And also used to manage chronic pain such as complex regional pain syndrome and failed back surgery syndrome [2].

Aim of the work:

Compare the efficacy of serratus posterior superior intercostal plane block versus erector spinae plane block in thoracic spine surgeries at the level between T1 to T7 Primary outcome: NRS (Numerical rating scale) Secondary outcome: 1st dose of rescue analgesia, total doses of rescue analgesia, motor block, and 1st time of ambulation

Patients and methods:

This randomized double-blinded study will be carried out on 60 adult patients of both sexes undergoing elective thoracic spine surgeries in Tanta University Hospitals for a period of from April 2026 to December 2026.

Informed written consent will be obtained from the parents. They will receive an explanation of the purpose of the study, and every patient will have a secret code number. All data of the patients will be confidential with secret codes and private files for each patient; all given data will be used for current medical research only.

Any unexpected risks that appeared during the research will be cleared to the participants and ethical committee on time. Investigator who is blinded to group allocation provided postoperative care and assessments.

Inclusion Criteria: adult patients of both sexes undergoing elective thoracic spine surgeries aged from 18 years to 60 years, ASA I or II, thoracic levels between T1 to T7

Exclusion Criteria:

Parents refusal. Coagulopathy. Allergy to local anesthesia. Local infection at the site of injection. Pregnancy. Sever motor deficit (grade < 2) and sever sensory deficit (grade < 1).

Randomization and blindness:

Computer-generated randomization numbers will be used for random allocation and each patients' code will be kept in an opaque sealed envelope. Patients will be randomly allocated with 1:1 allocation ratio into three groups in a parallel manner:

• Group S (n=35): Serratus Posterior Superior Intercostal Plane Block will receive 30 ml of 0.25% bupivacaine on each side.
• Group E (n=35): erector spinae block group will receive 20 ml of 0.25% bupivacaine on each side.

Methods:

1. Preoperative:

   Medical and surgical history of the patients will be taken, clinical examination of the patients will be performed and routine laboratory investigations such as CBC, and coagulation studies.

2. Intraoperative:

   Monitoring (non-invasive blood pressure, pulse oximetry, electrocardiogram and temperature probe) will be applied during induction and maintenance of anesthesia. No premedication will be administered. The intravenous line will be inserted, give preload crystalloid 500 ml, preoxygenation 5 minutes with 80% oxygen. Anesthesia will be induced by injection fentanyl 1mic/kg, xylocaine 1mg/kg, propofol 1-2 mg/kg, and atracurium 0.5 mg/kg, ventilation with mask for 3 minutes then intubation using armored tube. Anesthesia will be maintained with isoflurane, O2 to Air 50%: 50%, be sure adequate preload and adequate blood pressure then change the position of patients from supine to prone position, take precaution of prone position and make sure there is no compression on eye. nose. breast, chest, abdomen, genitalia, knee and dorsum of foot, avoid over abduction of upper limbs more than 90 degrees and take care of brachial plexus and radial nerves.

   In group S: patients in prone position, the skin will be sterilized with betadine 10% at the site of needle entry A linear probe will be placed near the medial border of the scapula and using the in-plane technique a 22-G, 80-mm block needle will be inserted between the third rib and the SPSm will be confirmed by injecting 0.5-1 ml of saline and observing the fluid lifting the serratus superior posterior muscle , 30 ml of 0.25% bupivacaine will be injected on each side .

   In group E: patients in prone position. Using strict sterilization techniques, the skin will be sterilized with betadine 10 % at the site of needle entry. The level of the thoracic vertebrae at which surgery will be proceeded will be determined on ultrasound and the block will cover 2 levels above and 2 levels below. The linear probe will be placed at the mid-vertebral line in the sagittal plane. The transducer will be shifted 3.5-4 cm laterally from midline to the surgical side to visualize the erector spinae muscle and transverse process. Using the in-plane technique, a 22-G, 80-mm block needle will be advanced until the transverse process will be reached. The correct location of the needle tip in the fascial plane deep to the erector spinae muscle will be confirmed by injecting 0.5-1 ml of saline and observing the fluid lifting the erector spinae muscle off the transverse process while avoiding muscle distension (hydro dissection). Once the needle will be at the correct location, a negative aspiration test will be confirmed. Bupivacaine 0.25% at a dose of20 ml will be then injected on each side.

   Surgery will be initiated 15-20 minutes after performing the blocks, follow up hemodynamic changes intraoperative, using BSI and maintain the level to be between 40-60 %, paracetamol 1gm will be given.

3. postoperatively: patients will be extubated after returning the position to supine position, shifted to PACU, another investigator who will be blinded to group allocation provided postoperative care and assessments. Morphine will be given as rescue analgesia in a dose of 0.05 mg /kg.

Measurements:

All the following data will be collected:

Demographic data: age, sex, weight, ASA class. Hemodynamic parameter (MAP- Heart rate) Motor functions will be assessed using the following muscle power scale from 0-5 at (PACU- 1h, 2h, 4h,8h,16h and 24h postoperatively) Total doses of morphine as a rescue analgesia. First dose of morphine as a rescue analgesia in dose of 0.05 mg/kg. NRS (numerical rating scale) (PACU- 1h, 2h, 4h,8h,16h and 24h postoperatively)

1st time of ambulation. Adverse events: hypotension, hematoma, infection and LAST.