THE EFFECT OF LOCAL-ANESTHESIA WITH VASOCONSTRICTOR ON GINGIVAL BLOOD-FLOW DURING LEFORT-I OSTEOTOMY

Purpose: In earlier studies, it has been documented that maxillary gin gival blood flow (GBF) decreased significantly during the intraoperati ve course of a Le Fort I osteotomy. It was not clear, however, whether the observed decrease in GBF was caused by the osteotomy or by the us e of local anesthetic with vasoconstrictor (LA + V). The purpose of th is study was to measure the effect of LA + V on GBF during Le Fort I o steotomy using laser Doppler flowmetry (LDF). Patients and Methods: Us ing a randomized clinical trial study design, patients undergoing Le F ort I osteotomy were assigned to either a treatment (group 1, LA + V u sed) or a control group (group 2, LA + V not used). The predictor vari able was group assignment (LV + V used or not used). The outcome varia ble was mean maxillary GBF. Maxillary GBF was recorded at predetermine d times during the operation. Other study variables included age, sex, single- or double-jaw surgery, estimated blood loss, direction and ma gnitude of maxillary movements, temperature, pulse, mean blood pressur e, O-2 saturation, and duration of operation. Results: There were 19 p atients in group 1 (LA + V used) and 15 patients in group 2 (LA + V no t used). In both groups, mean maxillary GBF decreased significantly du ring the operation (group 1, 33.3 +/- 13.1 to 16.9 +/- 16.1 mL/min/100 g tissue, P =.015; and group 2, 48.2 +/- 17.1 to 15.5 +/- 7.6 mL/min/ 100 g tissue, P =.001). The decrease in GBF occurred much earlier in group 1. By an average of 2.3 hours into the operation, the mean GBF w as equivalent in both study groups (group 1, 10.6 +/- 8.6, and group 2 , 13.1 +/- 9.4 mL/min/100 g tissue, P =.44). Conclusions: The results of this study confirm earlier findings that mean maxillary GBF decreas es significantly during the intraoperative course of a Le Fort I osteo tomy. In addition, LA + V significantly affects GBF during the early p hase of the operation. Its effect, however, dissipates between the tim e of soft tissue dissection and maxillary downfracture.