European Journal of Cardiovascular Medicine

Lumbosacral spine fixation surgery is currently among the most common spine surgeries performed by neurosurgeons and spine surgeons. These procedures are performed for a variety of reasons, which may be congenital, degenerative, neoplastic, or spinal injury. The basic purpose of this operation is to stabilize and connect the lumbar and cervical spine, reduce pain in the lower back of patients, improve the quality of life and return to daily activities in a short time.(1,2)

Instrumentation of the spine in this operation results in severe postoperative pain that bothers most patients and can prolong hospital stay and prolong rehabilitation time.(3) Postoperative pain seen immediately after lumbosacral fixation surgery is either musculoskeletal pain or acute inflammatory pain that begins with an inflammatory disease. . tissue reactions and decreases over time with wound healing, with the risk of developing chronic low back pain if not treated early and adequately.(4)

Dexmedetomidine is a highly selective alpha 2-adrenoceptor agonist with sedative, anxiolytic, sympatholytic and analgesic effects and minimal depression of respiratory functions.(5-7) Dexmedetomidine acts on pre- and postsynaptic sympathetic nerve endings and the central nervous system, reducing sympathetic outflow and noradrenaline release. causes sedation, anxiolytic, analgesic and sympatholytic effects. It lacks opioid-like properties, so adverse opioid-related side effects have not been identified.(8)

Recently, the use of dexmedetomidine as a local anesthetic adjuvant has sparked interest in regional anesthesia and analgesia for a number of reasons. It shortens the onset of anesthesia, prolongs the duration of peripheral nerve blockade, reduces postoperative pain with maximum analgesic effect and acceptable side effects.(9–14)

Since posterior lumbosacral spine fixation surgery is a common spine procedure nowadays for various reasons, and since this procedure is usually accompanied by moderate to severe postoperative pain, it is necessary to find effective and efficient postoperative analgesia for patients. The aim of this study was to compare the analgesic effect of dexmedetomidine in combination with bupivacaine versus bupivacaine alone for ESPBfor postoperative pain control in posterior lumbosacral spine fixation surgeries.

Our study was done in a tertiary medical college in Central India from June 2023 to June 2024. Participants Patients over 18 years of age of either gender who underwent elective posterior lumbosacral spinal fixation and fusion surgery were eligible for participation if they were classified as ASA I–III according to the American Society of Anaesthesiologists (ASA) classification. All patients were operated on by the same surgical team and using the same surgical techniques.

Exclusion criteria included patient refusal, hypersensitivity to study drugs, patients with any contraindication to regional anesthesia such as skin infections at the block site, and patients with a history of bleeding disorders or taking anticoagulant medications. All patients were screened for eligibility criteria. Eligible patients were asked for voluntary informed consent to participate in the study.

All patients participating in this study were required to sign a detailed, informed, written consent for anesthesia and surgery.

The participants were randomly divided into three groups in a ratio of 1:1:1. Each group consisted of 25 patients. Dexmedetomidine Bupivacaine ESPB group (DB group) received 0.5 µg/kg dexmedetomidine plus 20 ml bupivacaine 0.25%, Bupivacaine ESPB (group B) receives 20 ml bupivacaine 0.25% and saline ESPB (S group), which is control group 0.20 ml normal saline. The block procedure was performed bilaterally in three groups. Preoperative management All patients were clinically examined before surgery, including complete medical history, thorough clinical examination, and laboratory tests. Upon arrival in the operating room, patients were fully monitored (5-lead ECG, non-invasive blood pressure and pulse oximetry). Basal vital signs values ​​were recorded. Intravenous access was established. Administration of anesthesia Midazolam 3 mg IV was administered for sedation. Anesthesia was induced with IV propofol (2 mg/kg), fentanyl (1.5–2 µg/kg), and rocuronium bromide (0.6 mg/kg). Anesthesia was maintained with isoflurane. Prone position was determined immediately after intubation. Data (peripheral oxygen saturation, heart rate, noninvasive arterial blood pressure, and end-tidal carbon dioxide level) were recorded every five minutes during surgery. Any decrease in heart rate below 50 beats per minute was treated with intravenous atropine, according to the response. Reductions in mean blood pressure below 20% of baseline or systolic BP below 90 mmHg were treated with 5 mg increments of intravenous ephedrine.

A nurse used a visual analogue scale (VAS; zero, no pain, ten = worst pain) to assess and record pain scores and record patients' opioid consumption. A nurse recorded passive (at rest) and active (on mobilization) VAS scores at intervals every two hours for the first 24 hours and every 4 hours for the next 24 hours, and total opioid consumption for the first 48 hours after surgery. Rescue analgesic medication was performed with pethidine 50 mg IM when the VAS passive pain score was >6. All patients were discharged home after 48 hours.

The confidence interval was set to 95%, and the margin of error accepted was set to 5%. So, the p-value was considered non-significant when the P-value > 0.05, significant if < 0.05, and highly significant if <0.01.

In our study a total of 75 patients were selected for the study who were randomized equally into the DB group (25), B group (25), and S group, which is the control group (25). The three studied groups were comparable regarding the demographic data (age and sex) without any significant difference between the three groups. No patients in any of the studied groups had a history of drug abuse or addiction (Table 1).

TABLE 1 showing socio-demographic data of patients in 3 groups

As regards the active VAS score in the first 24 hours, in the first two hours (Hr 2) postoperatively, there was no statistically significant difference between the three groups. There was no statistically significant difference between the DB and B groups in the second and third two hours (Hr 4 and Hr 6). However, there was a highly statistically significant difference when comparing the DB group by S group with a P-value <0.001.

In the second 24 hours, there was highly statistically significant difference according to the rescue analgesia by comparing DB group with B group (P-value 0.006) and a statistically significant difference between DB group with S group (p-value 0.01) (Table 2).

TABLE 2 showing Rescue Analgesia in 1st and 2nd 24 Hours

According to the total postoperative opioid (morphine) consumption, which was expressed as a number of PCA presses, there was a highly statistically significant difference when comparing DB group with B group and when comparing DB group with S Group in the first 24 and second 24 hours postoperative (P-value < 0.00) (Table 3).

TABLE 3 showing Total Postoperative Opioid Consumption (Number of PCA Presses)

As regards the intraoperative findings like bradycardia and hypotension between the three groups, there was no statistically significant difference between the three groups according to the intraoperative findings with a p-value > 0.05 (Table 4).

TABLE 4 showing Intraoperative and Postoperative Complications

According to postoperative complications, including nausea, vomiting, and pruritus in the first 48 hours postoperatively, there was a high Statistical significance difference between DB and B group regarding nausea, vomiting, and pruritus (P-value 0.001, 0.001, and 0.003), respectively.

There was a high statistical significance difference between DB and S group regarding nausea, vomiting, and pruritus (P-value < 0.00, 0.00, and 0.001), respectively (Table 4).

Binary regression analysis did not reveal any significant differences between the B and DB groups compared to the S groups concerning the presence of high levels of active and passive VAS scores (above 6) during the first 24 hours and the second 24 hours (Table 5). However, linear regression analysis indicated that the DB group exhibited a statistically significantly lower score for the number of PCA presses in both the first and second 24 hours, as well as a lower frequency of rescue analgesia administration during the same periods compared to the other groups (Table 5).

Table 5 showing Regression Analysis Between Primary Outcomes and Studied Groups (S, B, DB).

As is widely known that, Lumbosacral spine fixation surgeries is accompanied by severe, bothersome postoperative pain, which can prolong the hospital stay and delay the return to normal daily activities. There was an urgent need to provide adequate, effective, non-traditional techniques for postoperative analgesia.(1) After the first documentation by Forer et al in 2016, ESPB has been used to provide postoperative analgesia in thoracic and thoracoabdominal surgery, bariatric surgery, and more recently, ESPB has been used. to provide adequate postoperative analgesia during spinal operations. (5–7) In this study, we studied and evaluated additional analgesic effects of dexmedetomidine as an adjuvant to local anesthetic (Bupivacaine) to prolong the postoperative analgesic effect of ESPB in lumbosacral spine fixation surgeries. To our knowledge, there are many previous studies that revealed that different adjuvants added to local anesthetics in different regional anesthetic techniques had strong added analgesic effects, but there are only a few clinical studies on the addition of dexmedetomidine as an adjuvant to local anesthetics in ESPB, and also several of them satisfactorily assessed the quality of postoperative recovery. (18) Yi-han et al found that dexmedetomidine added to ropivacaine in ESPB can significantly reduce postoperative pain and have better analgesic effect at 12, 24, and 48 hours after surgery, and can reduce opioid consumption in patients undergoing posterior lumbar spine surgery without obvious adverse effects. effects as a local anesthetic adjuvant.(19) Gao et al reported that the duration of ESPB blockade could be prolonged by approximately 120% using dexmedetomidine (1 µg/kg) with 0.5% ropivacaine in combination with video-assisted thoracoscopic lobectomy.(20) Wang et al revealed that the addition of 1 μg/kg dexmedetomidine with 0.33% ropivacaine to ESPB in patients undergoing modified radical mastectomy can provide better postoperative analgesia and pain control than ropivacaine alone, thereby improving postoperative analgesia and pain control.(21) Wang et al. conducted a randomized controlled clinical trial to study the effects of adding dexmedetomidine as an adjuvant to ropivacaine for ultrasound-guided ESPB in esophageal cancer patients undergoing open thoracotomy. They found that the addition of dexmedetomidine to ropivacaine for ESPB effectively prolonged the duration of postoperative analgesia and reduced opioid consumption without additional side effects.(7) In addition, the results of our study were analogous to those of several other clinical trials that studied the effect of adding dexmedetomidine to a local anesthetic in nerve blocks other than ESPB, all of which showed that the addition of dexmedetomidine to a local anesthetic prolonged the block time and reduced the number of PCA compressions and the need for postoperative rescue analgesia, such as Almarakbi et al., who studied the effects of adding dexmedetomidine to bupivacaine in a plane transversus abdominis block in patients undergoing abdominal hysterectomy and noticed that the addition of dexmedetomidine to the block effectively prolonged the duration of postoperative analgesia without major adverse effects.(22)Rancourt et al also studied the effect of adding dexmedetomidine to ropivacaine in posterior tibial sensory block and noted an increase in the duration of the block. (13) In our study, we noted that a dose of 1 µg/kg dexmedetomidine when added to bupivacaine 0.25% in ESPB was safe and not accompanied by significant fluctuations in blood pressure or heart rate. However, there are many studies that have shown that dexmedetomidine is not safe at all doses and can cause systemic side effects at certain doses, as reported by Esmaoglu et al. found that the addition of 100 µg dexmedetomidine to the local anesthetic shortened the onset time and prolonged the duration of block and postoperative analgesia, but resulted in significant postoperative bradycardia.(23) Hussain et al also revealed that dexmedetomidine increased postoperative analgesia and prolonged brachial plexus block time, but significantly increased the possibility of intraoperative bradycardia when dexmedetomidine was injected perineurally at a dose higher than 50 µg.(24)

Dexmedetomidine as an adjuvant to bupivacaine used in ESPB to suppress postoperative pain during posterior fixation of the lumbosacral spine significantly increased the effectiveness and duration of ESPB analgesia (up to 36 hours), reduced passive and active VAS scores, reduced the need for acute analgesia service, reduced the number of PCA compressions (consumption opioids) and reduction of postoperative opioid side effects without additional intraoperative adverse effects of dexmedetomidine during the first 48 hours.

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