Effect of segmental Le Fort I osteotomy on maxillary tooth type-related pulpal blood-flow characteristics

Laser Doppler flowmetry (LDF) is a noninvasive method to assess pulpal blood-flow (PBF). Osteotomies may have segment-related losses of pulpal sensibility. OBJECTIVES: To determine the effect of segmental Le Fort I osteotomy on tooth-type related PBF values. MATERIALS AND METHODS: In 12 volunteers, maxillary incisors, canines, and premolars were investigated bilaterally by LDF to assess local PBF values before and after surgery. Perfusion units (PU) were in 3 sessions, on the day before surgery and at 4 and 56 days after osteotomy. RESULTS: Measurements before surgery were significantly higher than at 4 days after surgery for the canine (P <.01) and for the overall PBF values (P <.01). At 4 days assessment, PBF values of tooth types adjacent to vertical osteotomy cuts showed a significant decrease for the lateral incisors (P <.05), canines, and first premolars (P <.05), with no significant differences between the preoperative and postoperative values for tooth types not adjacent to vertical osteotomy cuts (P <.05). CONCLUSIONS: Segmental Le Fort I osteotomy induced a short-term and long-term decrease in maxillary PBF values of tooth types adjacent to vertical osteotomy cuts.     

Surgical complications of segmental Le Fort I osteotomy

Segmental maxillary osteotomy is a useful adjunct in orthognathic surgery for the correction of vertical and transverse maxillary deformities, but we know of few published reports that document complications. We evaluated the complication rates associated with segmental maxillary surgery in our unit by retrospective review of medical records, radiographs, and study models of 85 consecutive patients (mean age 23.3 years, range 14–51; male:female ratio 1:2) treated from 1995 to 2009. Types of deformity were anterior open bite (n = 30, 35%), transverse maxillary deficiency (n = 24, 28%), anterior open bite with transverse maxillary deficiency (n = 28, 33%), and anterior vertical maxillary excess (n = 3, 4%). There were 70 tripartite (82%), 13 bipartite (15%), and two quadripartite (2%) maxillas. Twenty-one patients (25%) had bone grafts. Fixation was done using titanium miniplates in 80 patients (94%), and titanium miniplates and resorbable plates in five (6%). The overall complication rate was 27%. Three patients (4%) had devitalisation of teeth, three (4%) developed minor periodontal defects, and one had tooth loss. Eight patients (9%) had plates removed, and two patients developed persistent postoperative palatal fistula. There was no segmental loss of bone or teeth. Our results show that complications in this cohort were relatively low, and that segmental maxillary surgery is safe as an adjunct in carefully selected cases.     

Incidence of maxillary sinusitis following Le Fort I maxillary osteotomy

Twenty adult patients with maxillofacial discrepancies most amenable to correction by Le Fort I osteotomy were evaluated for the incidence of postoperative maxillary sinusitis. Before surgery, each patient was evaluated both radiographically, by Waters' projection technique, and subjectively, according to a brief questionnaire pertaining to sinus symptoms. Identical evaluations were carried out at three- and six-month intervals following surgery. The results show no increase in the incidence of maxillary sinusitis following Le Fort I osteotomy.     

Surgical accuracy in Le Fort I maxillary osteotomies

The surgical outcome of planned movements of Le Fort I osteotomies is dependent on the surgeon's ability to achieve such movements intraoperatively. Our aim was to assess the surgical accuracy achieved for 30 consecutive patients undergoing Le Fort I osteotomies treated by one maxillofacial surgeon and his team. Method: Intraoperative control of the mobilized maxilla vertically was achieved by a combination of a nasion screw as the external reference point and bony marks above and below the osteotomy cuts intraorally. Movements horizontally and transversely were controlled with occlusal wafers. The surgical accuracy of maxillary movements vertically and horizontally (anteroposteriorly) were assessed by standard lateral cephalometric tracings of radiographs taken within two weeks prior to operation and 48 hours afterwards. Audit targets were arbitrarily set to be satisfactory when the difference between planned movements and actual movements as measured on the cephalometric tracings were 2 mm or less. Results: The mean (SD) difference from planned vertical movements of the anterior maxilla was 0.37 mm (SD 0.64) and horizontal movements 0.85 mm (SD 0.91). Ninety-seven percent (29/30) of anterior maxillary movements in the vertical dimension, 90% (27/30) of anterior maxillary movements in the horizontal dimension and 87% (26/30) of movements in both dimensions had a difference of 2 mm or less. These results were comparable with the reported 'gold standard'. Conclusion: Good surgical accuracy in positioning the mobilized maxilla in Le Fort I osteotomies can be achieved with the use of external and internal reference points.     

Management of postoperative hemorrhage following the Le Fort I maxillary osteotomy

The assessment and management of patients with postoperative hemorrhage following Le Fort I osteotomies is discussed. The results of a questionnaire to investigate this complication, as well as the authors' protocol for dealing with this problem, are presented. Three illustrative case histories are also presented.     

Traumatic arteriovenous malformation following maxillary Le Fort I osteotomy.

OBJECTIVE: Complications following maxillary Le Fort I osteotomy are rare. The authors present the rare complication of an arteriovenous malformation following such a procedure in a 25-year-old woman with a cleft lip and palate that was treated successfully with radiologically guided embolization.     

Le Fort I型截骨术上抬上颌骨与下颌骨自动旋转中心的相关性研究

目的:探讨Le Fort I型截骨术上抬上颌骨后,下颌骨自动旋转中心位置变化与上颌骨上抬距离的关系.方法:选取10例患者,均为上颌骨垂直向发育过度导致开唇露齿和下颌骨后下旋转,而下颌骨发育正常,采用单纯Le FortI型截骨术上抬上颌骨,矫正其牙颌面畸形.拍摄术前、术后头颅定位侧位片,利用Reuleaux法测量实际的下颌骨旋转中心位置,应用SPSS10.0软件包对ANS、PNS上抬量与下颌骨自动旋转中心位置进行Spearman秩相关分析.结果:下颌骨平均自动旋转中心位于蝶鞍点下方49.350mm、后方17.100mm处.髁突中心位于蝶鞍点下方24.000mm、后方11.950mm处.下颌骨自动旋转中心垂直向位置与ANS点的上抬量高度相关(P=0.008).下颌骨自动旋转中心垂直向位置与PNS点的上抬量高度相关(P=0.045).结论:下颌骨旋转中心位于髁突外.下颌骨自动旋转中心与上颌骨上抬幅度高度相关.     

The stability of Le Fort I maxillary osteotomies in patients with simultaneous alveolar cleft bone grafts

A retrospective study was performed on 20 patients who had been treated with Le Fort I maxillary osteotomies and simultaneous alveolar cleft bone grafts. The age range was 11 to 23 years, and there were 11 males and nine females. Changes in both anterior-posterior (A-P) and vertical direction were investigated using preoperative, immediate postoperative, and long-term postoperative lateral cephalometric radiographs. The results indicated little change between the immediate postoperative and long-term postoperative position of the maxilla in an A-P dimension, but in a vertical direction there was a great tendency for relapse.     

The origin of the Le Fort I maxillary osteotomy: Cheever's operation

The Le Fort I maxillary osteotomy so commonly performed today for a variety of reasons had its primitive beginnings in 1867 in the search for a more simple, direct, and less mutilating approach to the nasal cavity for tumor removal. David Cheever, firstly by his successfully repeated downfracture of the right hemimaxilla in one patient, who had complete recovery, followed by the technically successful total maxillary downfracture (although the patient died postoperatively), must occupy a foundation position in the history of the Le Fort I maxillary osteotomy.     

Late onset of abducens palsy after Le Fort I maxillary osteotomy

Abducens nerve palsy after low-level Le Fort 1 maxillary osteotomy is a rare complication, but with few cases reported, its true incidence is not known. We report an unusual case of late postoperative onset of abducens palsy that differs from existing case reports.     

Biomechanical evaluation of Le Fort I maxillary fracture plating techniques.

PURPOSE: This study used a biomechanical model to examine fundamental questions about rigid plate fixation treatment for maxillary Le Fort I fractures. Specifically, we sought to elucidate the principal strain patterns generated in miniplates and bite force transducers secondary to all masticatory forces, as well as the amount of permanent deformations incurred due to these loading forces. MATERIALS AND METHODS: Forty polyurethane synthetic maxillary and mandibular replicas were used to simulate the mandible and maxilla. Ten replicas were controls (group A). The other 30 were divided into 3 groups (10 each), according to the fixation techniques of 3, 2, and 1 miniplates each side (groups B-D), that were osteotomized in the Le Fort I fracture line on the maxilla. Different forces of masseter medial pterygoid, temporalis, and lateral pterygoid muscles were loaded onto the replicas to simulate different functional conditions (anterior incisor, premolar, and molar clenching). Rosette strain gauges were attached at predefined points on the plates and the bite force transducer to compare the stability and bite force of the different fixation methods for maxillary Le Fort I fractures. RESULTS: Statistically significant differences were found for the deformation of the plates among fixation techniques. The order of stability for each technique was: group B greater than group C greater than group D. In regard to bite force, no difference was found between those found with group A and group B (P > .05), whereas the bite forces of groups C and D were less than those of group A (P < .05). CONCLUSIONS: The fixation of 3 miniplates on each side provides sufficient stability and restores the bite force to the level of the intact maxilla. "The ideal fixation" with 2 miniplates on each side restores 90% of the bite force, and there were more deformations of the miniplates with the "ideal fixation" compared to those found with group B. Group D fixation produced the worst effects for the treatment of maxillary Le Fort I fractures with a weak bite force and insufficient stability.     

Treatment of maxillary deficiency by a Le Fort I downsliding technique

The treatment of patients with vertical maxillary deficiency by a Le Fort I downsliding technique where the maxilla is moved forward and downward on a planned angulated osteotomy cut, is discussed and the results in nine patients who were treated using this method are reported.     

Pattern of pterygomaxillary disarticulation associated with Le Fort I maxillary osteotomy

Pterygomaxillary disarticulation (PMD) contributes to surgical complications of Le Fort 1 osteotomy and is associated with undesirable fractures of the pterygoid plates. The aim of this paper was to investigate the patterns of PMD in Le Fort I osteotomies using Rowe's disimpaction forceps, and to evaluate correlations with age and anatomical measurements. Cone-beam computed tomography (CBCT) scans of 70 consecutive orthognathic patients were retrospectively evaluated to study four patterns of PMD: Type 1 - PMD at, or anterior to, the pterygomaxillary junction (PMJ); Type 2 - PMD posterior to the PMJ; Type 3 - PMJ separation with comminuted fracture of the pterygoid plates; Type 4 - disarticulation of the maxilla involving the pterygoid plates above the level of the osteotomy line. The preoperative anteroposterior and mediolateral thicknesses of the PMJ and the length of the medial and lateral pterygoid plates were assessed. Satisfactory PMD was achieved in all cases and no severe complications were reported, including vascular, dental, mucosal, or neural damage. The most common PMD was Type 1 (54.3%), followed by Type 2 (40%). Comminuted fracture of the pterygoid plates was limited to 5.7% of cases, and no Type 4 was detected. A weak correlation was detected between PMJ thickness and PMD pattern (p = 0.04). No statistically significant correlation was detected between patients’ age and type of PMD. PMD of Le Fort I maxillary osteotomy using a Smith spreader and Rowe's disimpaction forceps proved safe, with minimal damage to the pterygoid plates.     

下颌骨自动旋转中心与上颌骨上抬量的相关性研究

目的： 探讨Le Fort I型截骨术上抬上颌骨时下颌骨自动旋转中心的位置,下颌骨自动旋转中心与上颌骨上抬量、下颌骨长度和下颌平面角的关系。方法：选取25例单纯采用Le Fort I型截骨术上抬上颌骨矫治垂直向发育过度的患者,测量其术前、术后头颅定位侧位片。利用Reuleaux法测量实际下颌骨旋转中心。采用SPSS13.0软件包对ANS、PNS上抬量、下颌骨长度、MP-SN角度与下颌骨自动旋转中心进行Pearson相关和线性回归分析。结果：下颌骨自动旋转中心平均位于髁突中点下方15.64 mm,后方0.82 mm处。ANS点和PNS点上抬量、下颌骨长度与下颌骨自动旋转中心位置相关,MP-SN角度与下颌骨旋转中心垂直向位置相关。结论：下颌骨自动旋转中心位于髁突外,其与上颌骨上抬量、下颌骨长度和下颌平面角相关。