Topical anesthetic EMLA for postoperative wound pain in stereotactic gamma knife radiosurgery: a perspective, randomized, placebo-controlled study.

BACKGROUND: Patients who undergo stereotactic gamma knife radiosurgery (GKRS) need a rigid frame fixation for the stereotactic procedures. Many patients suffered from postoperative wound pain after frame removal. The present study investigated whether an additional application of a topical anesthetic prior to frame removal could reduce this discomfort.

PATIENTS AND METHODS: 60 patients who underwent GKRS were enrolled in this study. Of these 60 patients, 30 were treated with a topical application of EMLA, a eutectic mixture of 2.5% lidocaine and 2.5% prilocaine; the remaining 30 were treated with a placebo. The nurses explained the definition of the visual analogue scale (VAS, scored from 0 to 10), and the patients evaluated their pain at 7 time points during the GKRS procedure by using the VAS. After each of these evaluations, the patients' vital signs (blood pressure, heart rate, and respiratory rate) were measured.

RESULTS: There was no significant difference in the patients' age, gender, duration of frame fixation, and types of the lesions between the EMLA and placebo groups. The EMLA group reported significantly lower pain scores 20 and 60 min after frame removal than the placebo group (p=0.001 and p<0.001, respectively). Additionally, patients in the placebo group had significantly higher blood pressure readings compared with baseline data, during and after frame removal, thus indicating that postoperative wound pain caused them more discomfort after frame removal.

CONCLUSION: EMLA when applied 60 min before frame removal has an anesthetic effect of reducing the postoperative wound pain in patients who undergo GKRS.