# Surgical Complications of Orthognathic Surgery
## 3 Results  
This is a retrospective study. The study group included 103 patients (60 male, 43 female), with a mean age of 23.7 \(\pm\) 7.5 years (range 16-60 years). The most prevalent (67.9%) preoperative diagnosis was Skeletal Class III (CLIII), frequently combined with open bite (54%), followed by Skeletal Class II (CLII) (Table 1). All patients had preoperative orthodontic treatment with standard fixed appliances. The most common surgery type, constituting over half (57%) of the surgeries, was LF1 + BSSO, followed by LF1 alone and then BSSO Genioplasty (GP) (Table 2). The surgeries were performed by all the staff in the department--including faculty and residents--randomly assigned. During surgery, the maxilla was cut using reciprocating saw, while mandibular osteectomies were performed by Lindemann drill. All surgeries were performed under hypotensive anesthesia--using Nitrates (sodium nitroprusside, nitroglycerin) alone or combined with \(\beta\)-adrenoceptor antagonists (e.g., propranolol and esmolol) or calcium channel antagonists (e.g., nicardipine). In all cases, rigid internal fixation with titanium miniplates and screws were used for osteosynthesis (1.5 mm miniplates for the maxilla, 2 mm plates for the mandible). Assessing correlations between primary diagnosis and surgery type revealed a significant (\(p\) = 0.003, Fisher's Exact Test) connection between Skeletal Class II and Skeletal Class III diagnoses and the probability of two jaw (bimaxillary) surgery (Figure 1). The correlation is strongest for Skeletal Class III diagnosis where 70% of the patients underwent two jaw surgery (61.4% of LF1 + BSSO alone). Maxillo-Mandibular Fixation (MMF-wires) was used to guide occlusion for the first 6 weeks post-operatively using blenderized diet. The post-operative protocol includes hospitalization for a week, then routine check-ups twice a week for the first two weeks, then weekly for the next 6 weeks, then once a month until 6 months post-operatively and once in 3 months until 18 months post-operatively. The patients did not resume professional or physical activity up until 7-8 weeks after the surgery. Post-operative orthodontic treatment was also resumed at 8 weeks. There were 2 incidents of a severe complication which was major bleeding after LF1 surgery, requiring 3 units of blood transfusion. Cases of moderate complications included (i) 3 incidents having permanent nerve (Inferior alveolar nerve--IAN) injury (2.9%), all of which occurred after LF1 + BSSO surgeries, after at least 12 months and (ii) 6 cases requiring a second surgery (5.7%, 2 after LF1 and LF1 + BSSO, 1 after LF1 + BSSO + GP and BSSO). In our study group the probability of moderate surgical complications was 9.6%. The most prevalent minor complication was temporary nerve (IAN) injury (29.3%) and complications related to hardware (27.6%). There were 56 complications in total (54.4%) and as 9 patients presented more than 1 complication, only 45 patients (43.7%) presented complications--giving an odd of 0.77 per patient to suffer complications after surgery. The most prevalent complication was temporary nerve injury followed by hardware complications (loose hardware, broken hardware). The complete data including the probability of complication per patient and relative risk of complication per patient (compared to LF1 + BSSO as being the most prevalent surgery) are presented in Table 3. Analysis was carried out on surgeries grouped as two-jaw and one-jaw surgery Analysis revealed that one-jaw surgery results in significantly less complications than two-jaw surgeries (\(p\) = 0.019, Fisher's Exact Test) as is clearly demonstrated in the 1.34 OR (Odds Ratio) of a patient having complications after a two-jaw surgery (Table 4). It was also found that the RR (Relative