Outfracture of the inferior turbinates during superior repositioning Le Fort I osteotomy with cone-beam computed tomographic analysis of the volume of the nasal cavity

Influence of the Inferior Turbinate on the Accuracy of Superior Maxillary Repositioning

Notably, many studies have focused on the bony interference in the maxillary segment when performing maxillary superior repositioning; however, few reports have described the interference with the inferior nasal turbinate. Therefore, the authors aimed to retrospectively analyze the soft tissue or bone tissue volume of the inferior nasal turbinate and the accuracy of maxillary superior repositioning in Le Fort I osteotomy (LF1). The authors included 83 patients with facial deformities who underwent conventional LF1 (maxillary molar elevation between 4.0 and 6.0 mm) with/without bilateral sagittal split ramus osteotomy. The ratio of the soft tissue of the inferior turbinate to that of the inferior nasal cavity was used to divide the participants into 2 subgroups (large and small ratio). Similarly, the bony tissue volume of the inferior turbinate was used to divide the participants into 2 subgroups (large and small bony tissues), and the planned or actual amount of superior repositioning was compared 3 dimensionally. In the soft tissue group, the subgroups showed no significant differences (P=0.934). However, the actual maxillary superior repositioning was significantly lower in the large bone group than in the planned maxillary elevation group (P<0.01). In cases where the maxillary molar needs to be elevated by >4 mm and the bone tissue of the inferior nasal turbinate is well developed, an adjunctive technique such as horseshoe osteotomy or partial inferior turbinate resection should be considered in addition to LF1 to avoid interference between the inferior nasal turbinate and the maxillary bone fragments.

Morphological changes in the inferior nasal passage associated with superior repositioning of the maxilla with/without horseshoe osteotomy or turbinectomy

Superior repositioning of the maxilla during Le Fort I osteotomy (LFI) may narrow the inferior nasal passage. This retrospective study was performed to investigate morphological changes in the inferior nasal passage following LFI with/without additional procedures performed for nasal ventilation (horseshoe osteotomy or inferior turbinate partial resection). Three groups of patients were compared: those undergoing conventional LFI (Conv, 63 patients), LFI with horseshoe osteotomy (Hs, eight patients), and LFI with inferior turbinate partial resection (Turb, 21 patients). Coronal computed tomography images were used to evaluate the degree of stenosis of the inferior nasal passage. The soft tissue and bony tissue volumes in the inferior turbinate were also calculated three-dimensionally. The rate of obstruction of the inferior nasal passage postoperative was 65.9%, 50%, and 11.9% in the Conv, Hs, and Turb groups, respectively (Fisher's exact test, P < 0.001). Patients in the Turb group had significantly less nasal obstruction regardless of the pitch direction of the maxillary movement or volume of the bone in the inferior turbinate (all P < 0.001). In conclusion, for patients with high superior repositioning and well-developed bony tissue in the inferior turbinate, additional procedures are recommended to maintain the ventilation of the nasal passage postoperatively.

Efficacy of Nostril Supportive Splint Treatment for Nasal Septum Deformities after Le Fort I Osteotomy

This retrospective study aimed to evaluate the efficacy of support splint treatment for deformities and deviations of the nasal septum after Le Fort I osteotomy (LFI). Patients were divided into two groups: the retainer group wore a nasal support splint immediately after LFI for 7 days, and the no retainer group did not wear a nasal support splint. Evaluation was performed by measuring the ratio of the difference between the left and right sides of the nasal cavity area (ratio of nasal cavity) and the angle of the nasal septum using three computed tomography frontal images (anterior, middle, and posterior) before and one year postoperatively. Sixty patients were included and divided into two groups, the retainer and no retainer group (n=30 each). Regarding the ratio of nasal cavity on middle images at one year postoperatively, the retainer and no retainer groups differed significantly (0.79±0.13 and 0.67±0.24, respectively; P =0.012). The angle of the nasal septum on anterior images at one year postoperatively was 164.8±11.7° in the retainer group and 156.9±13.5° in the no retainer group, showing a significant difference ( P =0.019). This study suggests that support splint treatment after LFI is effective in preventing post-LFI nasal septal deformation or deviation.

Study of Morphological Changes in the Inferior Turbinate After Le Fort I Osteotomy

OBJECTIVE

There are cases in which patients complain of nasal obstruction after Le Fort I osteotomy, but the relationship with postoperative morphological changes in the nasal cavity, including the septum and inferior turbinate, is not clear.

STUDY DESIGN

The authors evaluated the three-dimensional relationship of the morphological changes in the inferior turbinate before and after surgery in 84 patients who underwent Le Fort I osteotomy. Three classifications were made according to superior amount of maxillary movement at the base of nasal cavity.

RESULTS

The high elevation group (4.0 mm or more) had 31 sides, the moderate elevation group had 93 sides, and the low elevation group (less than 2.0 mm) had 44 sides. The volume of inferior turbinate was 76.9 ± 12.8% of that before surgery in the high elevation group. The high- and moderate-elevation groups had significantly higher changes than the low elevation group, and the rate of contact between inferior turbinate and nasal cavity floor was 67.7%.

CONCLUSIONS

After Le Fort I osteotomy, the volume of inferior turbinate tissue decreased in proportion to the amount of elevation of the maxilla. Although the soft tissue volume may be reduced due to adaptation of respiratory function, the inferior nasal passage was not completely ventilated in the high elevation group. If the elevation exceeds 4.0 mm counterclockwise with maxillary movement, it is necessary to consider the concomitant inferior turbinate resection because it may lead to nasal obstruction.