Table 5. Transfusion rate for Le Fort I single jaw surgery with additional procedures. Predonation policy Study n/N % No predonation policy Ash and Mercuri (1985) 2/6 33.3 (4.3;77.7) Samman et al. (1996) 6/69 8.7 (3.3;18.0) Yu et al. (2000) 0/12 0 (0.0;26.5) Zelllin et al. (2004) 0/14 0 (0.0;23.2) Landes et al. (2008) 0/4 0 (0.0;60.2) 8/105 7.6 (3.9;14.5) Hegtvedt et al. (1987) 3/34 8.8 (1.9;23.7) Moenning et al. (1995) 0/20 0 (0.0;16.8) Total 3/54 5.6 (1.8;15.9) 11/159 6.9 (3.9;12.1) Total Predonation policy Overall total 95% CI The overall transfusion rates are estimated using a logistic regression model. Where n is the number of patient and N is the total number of patient. in the no-predonation policy group. Complex Le Fort I surgery should not be underestimated. It usually is more difficult to advance a maxilla to an extent that a bone graft is needed. Certainly, complex isolated Le Fort I surgery with multiple segments and additional bone graft– harvesting procedures may be more challenging and time consuming than straightforward bimaxillary procedures where the magnitude of movements is smaller, often to overcome the difficulty of a large single-jaw movement, which in addition is less stable. In this series of 211 complex single Le Fort I osteotomies, 181 were performed before the year 2000 and 30 after. None of these 30 required a blood transfusion. 3.1.4. Bimaxillary surgery without additional complex procedures The aggregation of data allowed inclusion in this category of the normal Le Fort I one piece with BSSO (advancement, rotation, or set-back). If an author stated that a two-piece or a straightforward genioplasty was considered in this group because of the ease of the routine not adding much to the duration of the surgery, this was accepted in this category. If any additional procedure was not accounted for by the author when discussing ‘bimaxillary osteotomies’, these were accommodated in this category. The group with predonation consisted of the following papers (numbers of patients in favoured because blood losses over 1000 mL and hematocrits of 26% and 29% were not transfused because of a stable clinical condition. Moenning et al. (1995) 14 used a strict transfusion trigger, even for autologous blood, and stated that the hemoglobin level must be below 7 g/dL and the hematocrit below 21% before transfusions were indicated for a symptomatic patient requiring autologous blood. It is obvious that predonation does not preclude the use of strict transfusion criteria. If these are met, no clinically significant difference in transfusion rate is observed between a predonation and no- predonation policy. A statistical analysis of this group was done in SAS; 95% exact confidence intervals were calculated for the individual studies. The overall transfusion rates and corresponding 95% confidence intervals were estimated using a logistic regression model. No significant difference between predonation and no-predonation policy could be shown. (p=0.6288) The intra-study correlation was not estimable using a beta-binomial model and hence set to zero. For this reason no probit-model was used and a logistic regression model was chosen (Fig. 2). The transfusion rate for Le Fort I single-jaw osteotomy without additional complex procedures is 4.5% according to the statistical model in the no- predonation policy group, whereas the addition of complex procedures to a Le Fort I single-jaw osteotomy increases the transfusion rate up to 7.6% TRANSFUSION NEED IN ORTHOGNATHIC surgery - A REVIEW Table 6. Transfusion rate in Le Fort I single jaw osteotomy with additional surgery: predonation policy versus no-predonation policy. Le Fort I single-jaw surgery with additional complex procedures n° patients n° patients Autologous/ transfused homologous % Predonation policy 54 3 Autologous 5.6% No predonation policy 105 8 Homologous 7,6% 159 3 Stomatology Edu Journal 6.9% 189