the plan of treatment of deformities of the jaws includes pre - surgical orthodontic treatment designed to eliminate dental compensations present ( i.e. , the anomalies of the teeth that have taken place ) and the preparation of the dental arches in relation to the scheduled surgery . in the field of orthodontics and surgery , studies have been carried out to improve some characteristics like the modulus of elasticity and frictional modulus of orthodontic appliances . although the le fort i osteotomy is a safe surgical technique , many complications have been reported with a low incidence of occurrence . these include swelling , haemorrhage , infections , nerve injuries , bone necrosis , tmj problems , periodontal disease , ophthalmic and middle ear disorders , dysphagia and psychological problems . in particular , vascular complications can arise from direct trauma to the vessels due to the blind nature of the osteotomy in the maxillary posterior area . unwanted fracture lines may also extend to the pterygopalatine fossa , skull base and to the orbit . as a rule , the osteotome position during pterygomaxillary separation is contiguous to the internal maxillary artery ( i m a ) , therefore , complications are rare . the entire course of internal maxillary artery ( i m a ) from its retro - mandibular origin to its termination within the pterygopalatine fossa is vulnerable to iatrogenic injury . therefore , to avoid possible delayed complications and facilitate their management , continuous postoperative monitoring is essential . the descending palatine artery is the vessel most often involved in traumatic injuries during orthognatic surgery of the maxilla . less often , the maxillary artery and its terminal branches , the pterygoid venous plexus , the internal carotid artery , and internal jugular vein may be damaged . we present a case of an extended cervico - facial haematoma due to delayed bleeding from the terminal branches of the maxillary artery after orthognatic surgery . a 23-year - old man was referred to the department of maxillofacial surgery , university of verona , italy for the surgical correction of a class iii asymmetric malocclusion [ figure 1a ] . the patient underwent a le fort i osteotomy , with impaction of the maxilla associated with an epker mandibular bilateral sagittal split ramus osteotomy , with maxillary advancement and rigid internal fixation of the mandible with four miniplates ( osteomed ) , and four miniplates for the upper maxilla as well . class iii asymmetric malocclusion the patient had a medical history of one wisdom tooth extraction , performed under local anaesthesia . preoperative vital parameters were : temperature , 36.4c ; heart rate , 62 bpm ; blood pressure , 120/65 mmhg ; respiration rate , 17 breaths per minute and 100% oxygen saturation . preoperative laboratory tests showed rbc , 4.86 e + 12/l ; hb , 14.1 g / dl ; ht , 43.1% ; coagulation tests were normal ( prothrombin time 1.05 inr , activated partial thromboplastin time 1.18 and fibrinogen 241 mg / dl , clauss method 7.11 the patient received a single - shot antimicrobial prophylaxis using 1 gm of amoxicillin , in addition to a single dose of corticosteroids ( 1 gm of methylprednisolone ) one hour before the operation . the surgical procedure was performed in general hypotensive anaesthesia , with the following parameters : blood pressure , 100/70 mmhg ; heart rate , 80 beats per minute and 100% oxygen saturation . sevoran , fentanile , remifentanyle , 1500 ml of crystalloids and 500 ml of colloids were infused . the first post - surgery day , the patient developed a gradual dispnea together with neck swelling . a cat scan with contrast agent was performed , showing a parapharyngeal thickening , with dislocation and compression of upper airways ; laboratory values were ht , 34.9 % ; hb , 12.3 g / dl ; rbc count , 3.81 e + 12/l . after 5 hours , a progressive worsening of the general condition led to immediate intubation . laboratory results in the emergency room were ht , 28.2% ; hb , 9.9 g / dl ; rbc count , 3.06 e + 12/l ; prothrombin time , 1.20 inr , activated partial thromboplastin time , 1.18 and fibrinogen , 452 mg / dl . the patient was sedated with midazolam and diprivan and was given amoxicillin vial gm , 1 fl every 8 hour a day and methylprednisolone vial 125 : 1 vial 3/die . the same night , a cat scan showed a wider extension of the haematoma on the upper and lower airways , together with a decrease in the diameter of the parapharyngeal space [ figure 1a and b ] . the patient underwent a bilateral carotid arteriography [ figure 2 ] , and a slight bleeding from the palatine branches of the left ascending pharyngeal artery which was probably closed by the arterial spasm induced by the catheter was revealed . other cat slices did n't show a significant difference in comparison with the first cat . haematoma on the upper and lower airways the patient underwent a bilateral carotid arteriography on the second postoperative day , the patient 's general condition improved with a progressive normalization of laboratory tests values . on the fourth postoperative day , total recovery from haematoma was achieved within two months and the final clinical check showed a healthy appearance with good occlusion . le fort i osteotomy is a standard orthognatic surgery procedure used for the correction of dentofacial deformities . it was first described by vom lagenbeck in 1859 and it was used for the first time in 1927 by wassmund . axhasen in 1934 and schuchardt in 1942 described the use of an osteotome to separate the pterygomaxillary suture . bell studied the biological basis for maxillary osteotomy , bone healing and revascularization after corticotomy . it is of great importance to understand the mechanism of the complications in order to minimize the potential risks . vessel injury may occur when the maxillary tuberosity is separated from the pterygoid plates with an osteotome , or during the downfracture procedure . precious reported that pterygomaxillary separation can be achieved safely and easily by leverage alone without the use of a pterygoid chisel . he described the use of tessier 's spreaders , together with digital manipulation to achieve pterygomaxillary separation followed by maxillary mobilization . smith 's 3-prong spreaders , turvey 's maxillary expanders , and modified mobilisation forceps are also used to aid leverage . in le fort i osteotomy , most often , a haemorrhage arises from the branches of i m a . . collaterals of the i m a include the posterior , superior , alveolar , infraorbital , greater palatine , lesser palatine , ascending pharyngeal , vidian , and sphenopalatine . the descending palatine artery may be a common source of bleeding during and after le fort i osteotomy because of its anatomic location in the posteromedial wall of the maxillary sinus . arterial haemorrhage tends to be more persistent and can be recurrent , which makes it more difficult to manage . bleeding can occur intraoperatively during the osteotomy , but also within the first 2 weeks following surgery and generally presenting as epistaxis . in some cases , even months after the procedure , there can be a delayed presentation of pseudoaneurysm . in order to investigate the major cause of bleeding after a le fort osteotomy a cat scan is useful to define the newly established bone anatomy , the location of the pathology , and the vessel relationships to the fracture line . a cat scan with contrast agents provides faster , easily detectable and interesting clues for the type of pathology of the affected side . treatment modalities used to arrest postoperative haemorrhage include nasal packing , packing of the maxillary antrum , reoperating with clipping or electrocoagulation of the bleeding vessels , the use of topical haemostatic agents in the pterygomaxillary region and selective embolization of the maxillary artery and its terminal branches . according to literature , different embolization materials have been used with various degrees of success for pseudoaneurysm treatment : gelfoam , gianturco coils , stainless steel coils with gelatin or dacron fibres , guide wires , detachable balloons , n - butyl cyanoacrylate , autologous clot , polivinil alcohol , complex platinum coils , guglielmi detachable coils . concerns about the risk of haemorrhage as a result of pterygomaxillary separation led to the development of an osteotomy technique anterior to the pterygomaxillary suture . rohner described an endoscopically assisted le fort i osteotomy to ensure preservation of the descending palatine artery . ueki et al . recently reported the use of an ultrasonic bone curette to mobilize the pterygoid process , thus avoiding the damage to the descending palatine vessels . for the authors , the ultrasonic bone curette offers a safe procedure for performing pterygoid process fractures , without damaging the surrounding tissues . this technique allows surgeons to perform procedures in the pterygomaxillary area to safely mobilize the pterygoid process . during the intraoperative phase a straight follow - up of the patients is important in cases who may show vascular hypersensivity , able to cause a vessel spasm release the day after the operation . new trends for ambulatory surgery reduce costs for patients but can increase medical responsibility . for legal reasons , even if it is necessary to mention typical complications during preoperative counselling , it is ideal to follow up on patients with standard checkups . not only should the patient be informed about the frequency of complications , but he should also be told about its implications in later life . once a frequent complication , haemorrhage has become rare when the surgical technique is handled by an experienced orthognatic surgeon . sometimes , despite preoperative planning and a careful surgical technique it is important to check immediate or delayed postoperative bleeding also , using a protocol that can take care of day surgery patients . an increased knowledge of the basic biology of the le fort i osteotomy , the development of instruments specially designed for this le fort i procedure and the use of hypotensive anaesthesia have dramatically reduced the morbidity and duration of this procedure .