[Painless infiltration anesthesia in eyelid surgery. An intraindividual randomized prospective study].

[BACKGROUND] Local anesthetic infiltration before lid surgery causes pain of varying degrees. To reduce the patient discomfort we have tested the effect of an initial injection of deluted anesthetic prior to the infiltration anesthesia.

[PATIENTS AND METHODS] During August 1993 and April 1994 thirteen patients, 21 to 81 years of age had bilateral lid surgery (4 female; 9 male). Two injection techniques were studied in disease patients intraindividually. Part of the local anesthetic was deluted 1:10 with saline and initially injected on one side only. Three minutes later infiltration with 2-5 ml of full-strength 2% mepivacaine with adrenaline 1:200,000 was performed on both sides. Obvious signs of pain were documented and patients were questioned about their discomfort (score 0-3).

[RESULTS] Five patients were operated for bilateral ectropium (lateral canthal sling procedure 4, Lazy-T 1), seven patients for dermatochalasis and one patient for brow ptosis. All thirteen patients ranked the technique with the initial injection of deluted local anesthetic significantly less painful. 9 of 13 patients had painless local anesthetic infiltration. Only 4 patients reported minor discomfort during injection of the diluted anesthetic. Onset time and duration of anesthesia was identical in both groups.

[CONCLUSION] The initial injection of a 1:10 diluted local anesthetic allows a significant reduction of pain during infiltration anesthesia before lidsurgical procedures. While pH buffering with bicarbonate may cause permanent skin pigmentation, dilution with physiological saline is an effective and inexpensive alternative. With this technique even in children local anesthesia becomes possible.