Parecoxib as an Adjuvant to Scalp Nerve Blocks for Relief of Post-craniotomy Pain

Pain is common for the first 2 days after major craniotomy. Inadequate analgesia induced sympathetically mediated hypertension may lead to an increased risk for post-operative complications, such as arterial hypertension, intracranial hemorrhage, prolonged hospital stay, and mortality.Pain after craniotomy derives from the scalp and pericranial muscles.Scalp block with local anesthesia seems to provide effective and safe anesthetic management.Scalp block can be performed by directly blocking the six different nerves that provide the sensory innervation of the scalp in neurological surgery.Even if adrenaline as an additive agent, scalp block using 0.5% or 0.75% bupivacaine with adrenaline could only improve postoperative analgesic for up to six hours after craniotomy.However, pain is common for the first 2 days after major elective intracranial surgery, and the relatively short analgesic time of scalp nerve blocks does not seem to meet the requirements of craniotomy. Therefore, how to improve the quality and duration of scalp nerve blocks with local anesthetics is of great significance.Parecoxib is a NSAIDs that specifically inhibits the enzyme COX-2.Liu et al firstly applied parecoxib as an adjuvant to local anesthetics on peripheral nerve blocks and reported 20 mg parecoxib added to ropivacaine injected locally on the brachial plexus nerve prolonged the motor and sensory block times of the nerve blockade and ameliorated postoperative pain intensity for patients receiving forearm orthopaedic surgery. However, there has not been reported about local application of parecoxib on scalp nerve blocks. The investigators postulate that parecoxib may be also ideal for scalp nerve blocks for relief of post-craniotomy pain, and further research is needed.

The APONIA trial aims to establish whether scalp blocks with a mixture of ropivacaine plus parecoxib is able to relieve patients' postoperative pain compared with local anesthetics alone, thereby potentially changing medical practice.


Eligibility Criteria:
Inclusion Criteria:

* Patients aged 18 to 64 years
* American Society of Anesthesiologists (ASA) physical status of I, II and III
* Preoperative Glasgow Coma Scale (GCS) score of 15/15
* Scheduled for elective craniotomy under general anesthesia

Exclusion Criteria:

* Patients with chronic headache or chronic pain syndrome for any reason
* Patients with psychiatric disorders, uncontrolled epilepsy, coagulopathy, infection around puncture point
* Inability to understand and incapacity to use the pain scales before surgery
* Pregnancy or at breastfeeding;
* Participation in another intervention trial that interferes with the intervention or outcome of this trial
* History of allergies to any of the study drugs
* Refusal to participate or unable to acquire informed consent provided by the patients and/or legal guardian
* Having their first craniotomy surgery with an occipital bone defect
* Excessive alcohol or drug abuse, chronic opioid use (more than 2 weeks or 3 days per week for more than 1 month), use of drugs with confirmed or suspected sedative or analgesic effects, use of any painkiller within 24 hours before surgery
* Extreme body mass index (BMI) (\< 15 or \> 35);