Maxillary osteotomy surgery/orthognathic surgery is advised when an abnormally positioned jaw is giving rise to skeletally based malocclusions or cosmetic problems. It is also used to correct other problems such as obstructive sleep apnoea, to gain access to advanced tumours with intracranial extensions, and for other base of skull surgeries. A more recent use has been in the management of oculo-facio-cardio-dental syndrome.

The Le Fort I osteotomy for maxillary orthognathic surgery is based on the fracture lines described in the widely accepted classifications for midface fractures by the French military surgeon Rene Le Fort in 1901. Various techniques for the Le Fort I osteotomy have been developed over the years, by many surgeons, including that of down-fracture and posterior maxillary disjunction.

The main problem of the various techniques for the Le Fort I osteotomy is intraoperative bleeding and maintaining the blood supply to the osteotomized segment. The control of bleeding and vascular preservation after complete mobilization of the maxillary segments in order to avoid vascular necrosis were the main concerns of maxillofacial surgeons at the beginning of Le Fort I type osteotomy surgery. Avascular necrosis related to a lack of blood supply was one of the main complications after Le Fort I osteotomy and has been reported in some studies.

For these reasons, Turvey and Fonseca performed vascular studies on the maxillary artery anatomy and reported the importance of an accurate surgical technique in the posterior maxilla to preserve the integrity of the maxillary artery. The importance of posterior soft tissue pedicles for maxillary blood supply was investigated by Bell, Justus et al. (Doppler analysis), and Buckley et al., who suggested attention to vascular risk, particularly in patients using orthodontic appliances or post-surgical splints, which may induce unwanted pressure on the soft tissue pedicle. Tooth modification with narrowing of the pulp canals after Le Fort I osteotomy was investigated by Ellingsen and Artun. Life-threatening complications following Le Fort I osteotomies were, however, deemed to be very rare.

The main problems related to vascular compromise after maxillary mobilization are rupture of the descending palatal artery, postoperative thrombosis, perforation of the palatal mucosa in segmented maxillary surgery, and partial stripping or excessive tension of the palatal fibro-mucosa in maxillary expansion. Anatomical irregularities such as craniofacial dysplasia and orofacial clefts, as well as vascular anomalies, increase the risks of vascular problems following maxillary osteotomy surgery. In particular, in the segmented Le Fort I osteotomy, palatal fibro-mucosa preservation is an important factor to avoid partial necrosis and malunion of the maxillary bone fragments, especially in patients with orthodontic appliances or palatal splints causing pressure on the palatal mucosa. In cases of multi-segmental Le Fort I osteotomy, palatal perforations anteriorly in a horizontal direction are more worrisome from a vascular standpoint than perforations more posteriorly that are parallel to the direction of the greater palatine artery. Palatal perforations can be important even in single-piece Le Fort I osteotomies if there is a horizontal tear in the mucosa at the junction of the hard and soft palates, which can occur with a traumatic maxillary down-fracture.

Compromised maxillary perfusion and ischaemia following Le Fort I osteotomy is a potentially serious complication resulting in hard and/or soft tissue loss. Various studies have assessed the effect of the Le Fort I osteotomy on maxillary perfusion intraoperatively using Doppler flowmetry. However, none of the studies have compared the different techniques for performing the pterygomaxillary separation. The majority of studies have compared the perfusion of the maxilla to that of the mandible following an osteotomy—a setting that cannot control for all of the factors associated with the maxillary anatomy and osteotomy. Posterior maxillary disjunction in Le Fort I osteotomies is done most commonly at the junction of the maxillary tuberosity and the pterygoid plates, or through the maxillary tuberosity (third molar socket) area itself. However no clinical study has yet compared the intraoperative change in maxillary perfusion between the two techniques using Doppler flowmetry.

The aim of the present study was to evaluate the difference in perfusion, by intraoperative measurement of maxillary blood flow, between the two maxillary osteotomy techniques—separation at the junction of the maxillary tuberosity and the pterygoid plates, or through the maxillary tuberosity (third molar socket) area.