OBJECTIVETo develop and evaluate the application of the facial minimally invasive fat granules injection device with controlled pressure and quantity.

METHODSDue to the requirement of facial fat grafting (small volume, precision, high pressure), we developed the integrated device with handheld controller and motor. From Nov. 2013 to Mar. 2015, 50 cases who underwent facial fat transplantation were selected to receive facial fat grafting with the device on the right side and with conventional syringe on the left side as control. The clinical effect was assessed by patients, surgeon and one from the third party. The intraoperative pain, injection difficulty, postoperative swelling and hruising, complications and overall satisfactory were recorded. Pain intensity was assessed using digital classification method ( NRS). Therapeutic effect was evaluated using Likert 5 points scoring method. Chi-square test, Wilcoxon test and one-way ANOVA were used for statistical analysis.

RESULTSThe device has the advantages of minimal designed and easily handling. The injection speed is 7.2 mm/s with the fat injection volume as precise as 0.04 ml/s (0.0056 m/mm). Among the 50 cases, the excellent and good effect were achieved in 90% (45/50) on the right face, and 78% (39/50) on the left face (Z = -4.285, P < 0.01). Local nodes happened in 7 cases on left face, while none on the right face (χ² = 6.57, P < 0.05). Petechiae occurred in 21 cases on right face and 45 cases on left face (χ² = 5.37, P < 0.05). Pain was assessed as 3.7 ± 1.1 points on the right sides, and 5.2 ± 0.7 points on the left sides (F = 17.405, P < 0.01).

CONCLUSIONSThe facial minimally invasive fat granules injection device with controlled pressure and quantity has the advantages of easily handling, precisely controlled quantity with hotter effect, less pain and complication.