Comparison of the Analgesic Effects of Scalp Nerve Block and Intravenous Ibuprofen Applications Under the Guidance of Nociception Level Index (NoL) in Patients Undergoing Elective Supratentorial Craniotomy

Introduction: Scalp incision is a powerful nociceptive stimulus that can exacerbate rapid changes in hemodynamic and sympathetic activity. Management of hemodynamic stability is essential in neuro-anesthesia and can be challenging among neurosurgery anesthesiologists. Neurosurgery operations include steps with a lot of painful stimuli such as intubation, insertion of a head-pinning, and craniotomy. A good anesthetic technique can improve hemodynamic responses by reducing the incidence of complications such as intracranial hypertension, bleeding, and longer recovery time. Routine analgesic approach in the intraoperative and postoperative period of supratentorial craniotomy includes the routine use of paracetamol, opioids, scalp nerve block with proven effectiveness, and intravenous ibuprofen, which gives good results by reducing opioid doses in moderate-to-severe pain. Supratentorial craniotomy surgery, which requires tight hemodynamic control, needs effective analgesic methods.

Trial design: It is a prospective, randomized controlled, consisting of factorial groups, double-blind study.

Participants: This study will be carried out at Ankara University Faculty of Medicine İbni Sina Hospital (Altındağ, Ankara, Turkey) between November 2022 and February 2023. One hundred and two ASA I-III patients with a body mass index (BMI) below 30, aged between 18 and 65, who will undergo elective supratentorial craniotomy due to a brain tumor, are planned to be included in the study.

Interventions: The group in which IV ipurofen was administered was named Ibuprofen Group (Group I), the group in which scalp nerve block was applied Block Group (Group), and the group in which IV ibuprofen and scalp nerve block were applied together was named Ibuprofen+Block Group (IB Group). In the premedication unit, 800 mg of ibuprofen in 100 ml of normal saline will be administered to Group I and Group IB, and 100 ml of normal saline without ibuprofen will be administered to Group B as a 30-minute IV infusion. After intubation, a scalp nerve block with 20 ml of 0.5% bupivacaine will be applied to Group B and Group IB, and 20 ml of normal saline will be injected into the block sites in Group I.

Objective: The investigators aimed to show the effect of scalp nerve block and IV ibuprofen applications, which are routinely applied, on the optimization of the patient's process from induction to the early postoperative period. In addition, the investigators will examine the comparison of hemodynamic and analgesic effects of scalp nerve block and IV ibuprofen applications under the guidance of pain monitor, and their contribution to reducing opioid consumption, which has side effects such as postoperative nausea/vomiting, slowing of GI motility, respiratory depression.

Outcome: The primary endpoint of the study was the differences between the groups in the changes in the patients' nociception level (NoL) index, heart rate, and blood pressure parameters at the time of head-pinning and the first surgical skin incision.

Randomization: Randomization of the patients into 3 groups will be carried out using the closed envelope method.

Blinding: The patients included in the study and the practicing anesthesiologist do not know which patient is included in which group.

Scalp incision is a powerful nociceptive stimulus that can exacerbate rapid changes in hemodynamic and sympathetic activity. Management of hemodynamic stability is essential in neuro-anesthesia and can be challenging among neurosurgery anesthesiologists. A good anesthetic technique can improve hemodynamic responses by reducing the incidence of complications such as intracranial hypertension, bleeding, and longer recovery time. The stable hemodynamic not only provide an easy-to-perform surgical field, but also prevent serious complications such as bleeding, aneurysm rupture, and cerebral ischemia. In patients with impaired cerebral autoregulation, even a small increase in systemic arterial blood pressure can cause unexpected spikes in cerebral blood flow and intracranial pressure.

Neurosurgery operations include steps with a lot of painful stimuli such as intubation, insertion of a head-pinning, and craniotomy. In these patients where autoregulation may be impaired, it is extremely important to monitor the pain and provide adequate analgesia as well as providing sufficient depth of anesthesia in order to keep the hemodynamics stable.

Craniotomy consists of the steps of such as head-pinning in order to stabilize the head, making a skin incision, cutting the skull bone and removing the dura-mater and reaching the brain parenchyma. This process, which ends with the dura-mater incision, which the investigators define as the early intraoperative period, is the time period in which the most painful stimulus is observed, and accordingly, the increase in the level of vasoactive agents causes an increase in heart rate and blood pressure. In 86% of patients, there is pain of somatic origin, possibly involving soft tissue and pericranial muscles. Pain in this process is generally moderate to severe pain.

It has been reported that the pain after craniotomy is less than the pain after lumbar laminectomy for lumbar disc herniation. However, it has been shown that moderate-to-high pain may occur after craniotomy, especially in the first 2 hours postoperatively, and this is more common than previously thought. Increased oxygen consumption and catecholamine release caused by postoperative pain may predispose to intracranial hematomas by causing brain hyperemia and increased intracranial pressure. Local anesthetic infiltration or systemic analgesics such as non-steroidal anti-inflammatory drugs and opioids are used for craniotomy pain palliation. If the patient is conscious and feels pain after craniotomy, effective analgesia should be provided.

Routine analgesic approach in the intraoperative and postoperative period of supratentorial craniotomy includes the routine use of paracetamol, opioids, scalp nerve block with proven effectiveness, and intravenous (IV) ibuprofen, which gives good results by reducing opioid doses in moderate-to-severe pain. There are studies comparing drugs such as opioids, non-steroidal anti-inflammatory drugs (NSAIDs), ketamine, IV lidocaine, gabapentin in the prevention of the sympathetic response that occurs when entering the spiked cap and in the prevention of post-craniotomy pain and among these, scalp nerve block is accepted as the most effective analgesic approach.

Supratentorial craniotomy surgery, which requires tight hemodynamic control, needs effective analgesic methods. In this study, the investigators aimed to show the effect of scalp nerve block and IV ibuprofen applications, which are routinely applied, on the optimization of the patient's process from induction to the early postoperative period. In addition, the investigators will examine the comparison of hemodynamic and analgesic effects of scalp nerve block and IV ibuprofen applications under the guidance of pain monitor, and their contribution to reducing opioid consumption, which has side effects such as postoperative nausea/vomiting, slowing of GI motility, respiratory depression.

It is a prospective, randomized controlled, double-blind study. Randomization of the patients into 3 groups will be carried out using the closed envelope method. The group in which IV ipurofen was administered was named Ibuprofen Group (Group I), the group in which scalp nerve block was applied Block Group (Group), and the group in which IV ibuprofen and scalp nerve block were applied together was named Ibuprofen+Block Group (IB Group). The patients included in the study and the practicing anesthesiologist do not know which patient is included in which group.

Fentanyl (1-2 μg/kg) and propofol (2-3 mg/kg) will be used for anesthesia induction. Rocuronium (0.6 mg/kg) will be used as a muscle relaxant. Anesthesia maintenance will be provided with propofol and remifentanil infusion, keeping the bispectral index (BISTM) between 40-60 and the nociception level (NoL) index (PMD-200TM) between 10-25. The neuromuscular block depths of the patients will be monitored with train-of-four (TOF). As components of multimodal analgesia, 1 g paracetamol and 1.5 g magnesium sulfate will be administered as IV infusion to all patients after induction. Propofol and remifentanil infusions will be stopped after the end of the surgical procedure. Patients who have the appropriate level of consciousness and can perform simple commands will be extubated after the BIS value is above 80 and the TOF percentage is above 90.

In the premedication unit, 800 mg of ibuprofen in 100 ml of normal saline will be administered to Group I and Group IB, and 100 ml of normal saline without ibuprofen will be administered to Group B as a 30-minute IV infusion. After the infusion is over, the patients will be taken to the operating table. After the monitoring is completed, induction will be made and intubated.

After intubation, a scalp nerve block with 20 ml of 0.5% bupivacaine will be applied to Group B and Group IB, and 20 ml of normal saline will be injected into the block sites in Group I. Head stabilization will be achieved with a spiked head 5 minutes after the block application is completed. Normal saline solutions containing or not containing ibuprofen and the injectors used in the block will be prepared by the anesthesia technicians and the practicing anesthetist will be kept unaware of the content of the applied substance.

If the NoL value rises above 25 at all stages of the surgical process, an IV bolus of 0.5 mcg/kg remifentanil will be administered as a rescue analgesic.

Demographic characteristics such as the patient's name, surname, gender, age, weight, co-morbidities, American Society of Anesthesiologists (ASA) score will be recorded in the data collection form. In the intraoperative process, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), NoL value, BIS value parameters will be recorded before intubation, after intubation, before head-pinning, after head-pinning, before surgical incision, after surgical incision, before craniotomy, after craniotomy, before dura mater incision, and after dura mater incision.

In the intraoperative process, the times when rescue analgesics are needed will be recorded.

SPSS 11.5 program will be used in the analysis of the data. Mean±standard deviation and median (minimum-maximum) will be used for quantitative variables, and the number of patients (percentage) for qualitative variables. The Kruskal Wallis H test will be used to determine whether there is a difference between the categories of a qualitative variable with more than two categories in terms of quantitative variables, since the assumptions of normal distribution are not provided. Chi-square and Fisher exact tests will be used when the relationship between two qualitative variables is desired. To look at the before-after differences of the same measurement, if normal distribution assumptions are provided, the Paired-t test will be used, otherwise the Wilcoxon Sign test will be used. Statistical significance level will be taken as 0.05.

Eligibility Criteria:
Inclusion Criteria:

* Undergoing elective suptatentorial craniotomy surgery
* Body Mass Index (BMI) below 30
* ASA I-III patient

Exclusion Criteria:

* Patients with a history of allergic reaction to the drugs to be used in the study
* Patients with heart, kidney and liver failure
* Patients who refused to participate in the study