The analgesic properties of scalp infiltrations with ropivacaine after intracranial tumoral resection.
BACKGROUND
The issue of postoperative pain after neurosurgery is controversial. It has been reported as mild to moderate and its treatment may be inadequate. Infiltration of the surgical site with local anesthetics has provided transient benefit after craniotomy, but its effect on chronic pain has not been evaluated. Accordingly, we designed the present study to test the hypothesis that ropivacaine infiltration of the scalp reduces acute and persistent postoperative pain after intracranial tumor resection.


METHODS
This was a prospective, single-blinded study. Inclusion criteria were intracranial tumor resection, age > or = 18 or < or = 80 yr, and ability to understand and use a visual analog scale (VAS). Exclusion criteria were history of craniotomy, chronic drug abuse, and neurologic disorders. All eligible patients were randomly included in Group I (infiltration) or C (control). Postoperative analgesia was IV acetaminophen combined with nalbuphine. At the end of the surgery, Group I received an infiltration of the surgical site with 20 mL of ropivacaine 0.75%. Acute pain was evaluated hourly by VAS during the first 24 h. The analgesic effect of ropivacaine was evaluated based on total consumption of nalbuphine and VAS scores. The incidence of persistent pain and neuropathic pain was assessed at the 2-mo postoperative evaluation. We used the Student's t-test to compare total nalbuphine consumption, repeated measures analysis of variance with post hoc Bonferroni t-test for VAS score and the Fisher's exact test for chronic and neuropathic pain.


RESULTS
Fifty-two patients were enrolled, 25 in Group I and 27 in Group C. Demographic and intraoperative data were similar between groups. Group I showed a nonsignificant trend toward reduced nalbuphine consumption during the first postoperative day, 11.2 +/- 9.2 mg vs 16.6 +/- 11.0 mg for Group C (mean +/- SD, P = 0.054). VAS scores were significantly higher in Group C. Two months after surgery, persistent pain was significantly lower in Group I, 2/24 (8%) vs 14/25 (56%), P = 0.0003. One patient (4.1%) in Group I versus six (25%) patients in Group C (P = 0.04) experienced neuropathic pain.


CONCLUSIONS
Because pain is moderate after intracranial tumor resection, there is limited interest in scalp infiltrations with ropivacaine in the acute postoperative period. Nevertheless, these infiltrations may be relevant for the rehabilitation of neurosurgical patients and their quality of life by limiting the development of persistent pain and particularly neuropathic pain.