# Surgical Complications of Orthognathic Surgery
## 4 Discussion
At our institution, it is not standard to look for the nerve, if it is seen then its status is documented. Temporary injury occurred in 17.5% of cases, almost all in the IAN. This number is on the lower side of the range of previous reports [1; 23]. The second type of moderate complication identified in this study was the necessity for a second surgery or re-operation. This is usually a psychologically difficult outcome for the patient. The main indications are malocclusion recurrence or nonunion of the osteectomies. In this study, 6 patients (5.8%) underwent a second surgery, similar to rates previously reported [6]. Re-operation was performed for non-union or relapse. Accurate preoperative planning that takes in account relapse tendency and stable fixation are essential to reduce the risk of this complication. Hardware was removed in 19 cases; we did not include these in \"reoperation\". Undesired fractures (bad split) may occur due to an irregular osteotomy line or an unfavorable fracture and their incidence varies between 0.9-23% [1; 13; 23; 24; 25; 26]. There are reports that wisdom teeth in line of osteotomy increase risk of bad fracture [27; 28; 29]. These fractures most frequently occur in the lingual or the buccal plate of the mandible or, rarely, coronoid process or mandibular condye. Such fractures may be a risk factor for infections, bone sequestration of the fragments, delayed bone healing and nonunion. In this study, the prevalence of a bad split of the mandible is 3.6%, a relative less than other studies [18; 21; 29]. A careful osteotomy execution in the case of small mandibular height or thickness may prevent this outcome. In this study we had only 1 case of late infection (1%), one of the lowest compared to previous reports [2; 22; 23]. This underscores the success of our departments protocol for perioperative (2 h pre-op until up to 24 h post-op) antibiotic treatment (amoxicillin + clavulanic acid IV, clarithromycin IV for penicillin allergic patients). Dental injuries are one of the most common complications of orthognathic surgery. Such injuries result from tooth sectioning by the drill, periodontal disease, osteolytic lesions, root absorption and angular defects. In this study, the prevalence of dental injuries is 5.8%. Using of cutting guides is becoming increasingly popular and may decrease the incidents of tooth and nerve injury [30], as well as using correct drills and blades may help to prevent dental lesions during osteectomies [5]. Complications related to surgical fixation materials or \"hardware issues\" may cause surgical wound dehiscence, loss of screws, loss of fixation, plate exposure, plate rupture, bone structure mobility, bone necrosis, infection related to fixation materials, and infection related to the loss of fixation [31]. In many cases, the complication requires plate and screw removal. We found hardware issues to be one of the most prevalent complications (15.5%) and indeed most of those cases (81.3%) required plate and screw removal. This is consistent with documented in the literature [2; 6; 21; 32]. We did not include these as the complication rate because not all plate removals were due to infection as some of them were removed only due to discomfort reported by the patients. This study demonstrates a relationship between diagnosis and surgery type, operation type and complication probability and diagnosis and complication probability. The large number of surgery types prevented statistical analysis of the complication by exact surgery type. LF1 + BSSO surgery types are more significantly associated with CL II and especially CL III surgery. The explanation for this may be that CL I defects are often managed with one-jaw surgery because there is no need for significant Antero-Posterior movement. One the other hand, LF1 surgery was not conducted at all in CL II. This makes sense since CL II almost always results from a case of mandibular deficiency with or without horizontal maxillary excess, problems which cannot be corrected with LF1 surgery alone.