Preoperatively Administered Single Dose Diclofenac Reduces the Intensity of Acute Postcraniotomy Headache and Decreases Postoperative Analgesic Requirements- a Randomized, Controlled Trial

Before surgery, every patient's previous history was taken routinely and along with this, special attention was paid to a history of preoperative headache, its severity and any analgesics used regularly prior to surgery. In this study 200 cooperative adults (over 18 years) undergoing elective craniotomy were randomly assigned into two groups with: 100 patients received 7.5 mg midazolam and 100 mg diclofenac as premedication, while the other 100 members of the control group received only 7.5 mg midazolam one hour prior to surgery. Envelop randomization was used to schedule patients to diclofenac or to placebo groups. Neither the anesthetists, nor the physician obtaining the postoperative VAS scores were aware of the actual patient's grouping (diclofenac or placebo) during the entire study. For induction of anesthesia, we used propofol (1-2,5 mg/kgBW), whereas for maintenance of anesthesia we used the combination of fentanyl, rocuronium, and sevoflurane. Craniotomy and opening the dura occurred always after the tissue saturation of sevoflurane and low-flow anesthetic technique was applied at a sevoflurane concentration ranging from 1.2 to 2.1 V% as required for maintenance of adequate anesthesia. Fentanyl was administered as an initial bolus of 100-150 µg followed by a maintenance dose of 2 µg/kgBW/h. The total dose of fentanyl was calculated offline after the procedure in all cases. The surgical site was infiltrated by a combination of 2% lidocaine and epinephrine in all cases. All patients were admitted to the neurosurgical ICU for postoperative observation. A stepwise analgesic regimen was decided prior the study. Severity of pain was assessed regularly by the ICU nurses and additional analgesics were used if the patient complained a headache severity of VAS >3. In these cases additional paracetamol (1-2 g given intravenously) was administered. If this was not effective, an additional dose of 100 mg diclofenac was given to the patients. In case of further ineffectivity, tramadol was administered in a dose of 100 mg per os or iv. At the end of the study the cumulative dose of analgesics that was administered to the patients was calculated. For sake of clarity we transformed analgesic doses to equianalgetic doses of intramuscular morphine according to the table of the Oxford Pain Site and these values were used for further comparisons of analgesic requirements.

Pain assessment occurred at bedrest state by using a 0-10 scaled visual analogue scale (VAS). Assessment of actual VAS scores was regularly performed by the nurses of the neurosurgical ICU during days 1-5 and rescue analgesics were given according to the actual needs of the patients. An independent physician (who was unaware of randomization) performed an additional check of VAS scores by asking the patient, what was her/his worse pain during the day. As the patient's satisfaction was considered to be dependent on the worse pain, only these VAS scores were used for further analysis.

The investigators intended to answer the following study questions:

• Our research intended to examine whether 100 mg preoperatively give diclofenac reduces the incidence and severity of PCH on the first and fifth postoperative days.
• Is there a difference in the incidence and severity of PCH between patients who underwent infra- or supratentorial interventions?
• Does 100 mg preoperatively give diclofenac reduce intraoperative and postoperative analgesic needs?
• Does 100 mg preoperatively give diclofenac increase the incidence of postoperative hemorrhagic events?

Grouping of the patients: