Comparison between the classical and a modified trans-septal technique of alar cinching for Le Fort I osteotomies: a prospective randomized controlled trial

Abstract

The aim of this prospective randomized control trial was to analyse the efficacy of a new trans-septal alar base cinch suture in controlling alar width in patients undergoing maxillary intrusion and setback by comparing it with the traditional cinch suture. Statistical evaluation was carried out in 62 of 76 patients. Group I (31 patients) received the traditional alar base cinch suture, and group II (31 patients) received the alar base cinch suture with an anchoring bite taken through the nasal septum 10 mm behind its anterior edge. In both groups the accurate identification of alar fibroareolar tissue was facilitated by an 18 gauge green needle passed extra orally. Alar base width was measured before and 6 months after surgery using Vernier callipers. Preoperative alar base width for group I was 29.76 mm (1.901 SD) and for group II 29.79 mm (3.141 SD); the postoperative values were 32.42 mm (1.858 SD) and 29.94 mm (2.568 SD), respectively. Mean alar base widening was 2.661 mm (0.800 SD) in group I and 0.145 mm (2.050) in group II. The difference in alar widening was statistically significant ( p < 0.001). In conclusion, the trans-septal modified alar cinch suture offers better control of alar base architecture in maxillary intrusion and setback.

Le Fort I osteotomy is the procedure of choice for most maxillary deformities. The beneficial effects of orthognathic surgery on maxillofacial anomalies are profound, but a secondary effect of the procedure is the resultant alteration of nasal architecture. Nasal dimensions show many racial variations, but when measured from a frontal the ideal width of the alar base should equal the intercanthal distance. This can be assessed by drawing a vertical line inferiorly from the medial canthus.

Widening of the alar base is the most common side effect following maxillary osteotomies, as validated by many studies. This is thought to be secondary to transection of the perioral and perinasal musculature, which without re-approximation, results in subsequent muscle shortening and lateralization.

The classic alar cinch suture, originally described by Milliard in cleft patients, helps to alleviate this effect. Collins and Epker, Wolford and Westermark et al., used different techniques and reported a decrease in alar flaring when interalar base sutures were used. Most authors perform the classic alar cinch procedure intraorally by placing a double loop between the fibroadipose tissue under the alar cartilage on each side of the piriform aperture.

Recently Muradin and Rosenberg have described a modified alar cinch suture in which the suture passes through the nasal septum, 10 mm posterior to the nasal spine. This is done in conjunction with V-Y closure of the intraoral incision. This technique places the vector of the paranasal muscles more to the original preoperative sagittal position than with the classic alar cinch suture. A classic alar cinch suture would increase the ventro-cranial rotation of the nasal tip. When using the modified alar cinch suture, the rotation of the lateral crurae will be counteracted. Previous studies have analysed the effect of this modified suture on different parameters such as orofacial dynamic movements, labial form and rotation of nasal tip. The effect of the modified method of alar cinching specifically on the alar base architecture, in a randomized controlled manner, has not been studied.

The aim of this study was to compare the classic and the modified trans-septal techniques of alar cinching for the maintenance of alar base architecture following Le Fort I maxillary osteotomies in a randomized controlled trial. The authors tested the null hypothesis that there was no difference between the classic and modified alar base cinch sutures in the control of alar width after Le Fort I osteotomies.

Materials and methods

76 individuals volunteered to take part in this study. The study protocol followed a prospective, randomized, blinded and controlled clinical trial design. The patients and the statistician were blinded with regard to the kind of treatment received. Opaque, sequentially numbered envelopes were used for the concealed allocation of patients to trial groups. Each envelope contained the group assignment for one patient, which was determined in advance by a random number table. All surgical procedures were carried out in an identical manner by using identical sets of instruments. Patients did not receive any financial compensation for participating in the trial.

The inclusion criteria were patients above the age of 18 years undergoing Le Fort I maxillary osteotomies, which involved setback and superior repositioning of the maxilla. All the patients undergoing Le Fort I osteotomies had an incisal exposure > 5 mm. Cephalometric analysis along with clinical assessment was used to identify patients requiring Le Fort I setback and posterior repositioning. An increased maxillary depth, increased Frankfurt mandibular plane angle (FMA) and incisal exposure greater than 5 mm are the primary deciding parameters. Patients with associated syndromes or systemic diseases, asymmetries, history of facial bone fractures and those undergoing anterior maxillary osteotomies, Le Fort I advancements and inferior repositioning were excluded from the study. Randomization across the two groups eliminated differences in movements.

The 76 patients were divided into two groups. Informed consent was obtained from all patients and the institutional ethical committee approval was obtained.

The points on the nasofacial skin fold at which the alae curve and meet the upper lip skin were taken as reference points (points A and B) ( Fig. 1 ). The alar base was measured with Vernier callipers, taking care that excessive manual pressure was not applied and tissues were not distorted. Alar base records were made preoperatively and 6 months postoperatively. The change in width of the alar base at 6 months after operation was taken as a standard for this study as that is when soft tissue oedema is expected to have resolved. A single surgeon recorded all the measurements. The alar cinch suture was placed after the completion of the maxillary osteotomies and before closure of the mucosa.

Fig. 1
Right and left alae points marked at the nasofacial skin fold.

For the patients undergoing the classic method of alar cinching (group I) an 18-gauge needle was passed through the skin at the nasofacial skin fold (point A) through the fibroareolar tissue intraorally on one side. This accurately identified the alar musculature and a thick suture bite with 2’0 vicryl was taken at this point. The same procedure was repeated on the opposite side. Applying medial tension on the cinch suture and making sure that the medial movements of both alae were similar confirmed the correct anchoring of the fibroareolar tissue. The two free ends of the suture were tied together in the centre.

In the patients undergoing the modified trans-septal alar cinch suture (group II) an 18-gauge needle was passed through the nasofacial skin fold and fibroareolar tissue and a thick suture bite with 2’0 vicryl through the tissue was taken in a similar manner ( Figs. 2 and 3 ). After passing it through the other side, a third bite was taken through the nasal septum approximately 10 mm (as measured with a Vernier calliper) posterior to the anterior edge of the nasal septum ( Figs. 4 and 5 ). The suture was then tightened across these 3 points ( Fig. 6 ).

Fig. 2
18-gauge needle passing through the right ala point, at the nasofacial skin fold and emerging intra orally, thereby identifying accurately the fibroareolar tissue.

Fig. 3
2’0 vicryl suture passing through it alar base fibroareolar tissue.

Fig. 4
Dissection of the nasal septum and marking a distance of 10 mm from its anterior end with Vernier calliper.

Fig. 5
Passing the third suture bite through a point that is 10 mm behind the anterior end of the nasal septum.

Fig. 6
Suture tightening.

Statistical analysis was performed using SPSS Version 17 for Windows (SPSS, Chicago Inc., IL, USA). Intra-group differences between the pre- and postoperative alar widths were analysed with the paired t test. The difference between the two groups was measured using the independent t test. A p value less than or equal to 0.05 was considered significant.

Results

76 patients entered the trial, of whom 6 did not check-in for the follow-up examination after 6 months. In 8 patients the trans-septal suture cut through the nasal septum. Of these, 5 patients had a very thin nasal septum and 3 patients had a superior repositioning of more than 8 mm. The width of the septum at that point was very thin. These 8 patients were not included in the study. Complete data sets from 62 patients (31 in each group) were statistically analysed. There were 14 men and 17 women in group I and 11 men and 20 women in group II. The mean age in group I was 24 years (range 18–38 years) and 27 years (range 18–45 years) in group II.

The mean superior repositioning of the maxilla in group I was 5.2 mm (3 SD) and in group II was 5 mm (3 SD). The mean posterior setback in group I was 4 mm (1.8 SD) and in group II was 4.2 mm (2 SD). No attempt was made to stratify the results according to the preoperative skeletal discrepancy, or the magnitude and direction of the maxillary movement, as to do so would have produced subgroups too small for analysis.

The mean pre- and postoperative alar widths for the two groups are given in Table 1 . Mean alar base widening was 2.661 mm (0.800 SD) in group I and 0.145 mm (2.050 SD) in group II. The independent t test revealed highly significant differences in the postoperative alar widths between the groups ( p < 0.01). Thus the null hypothesis was rejected. The modified trans-septal group demonstrated far better control of postoperative alar width compared to the classic method.

Jan 24, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Comparison between the classical and a modified trans-septal technique of alar cinching for Le Fort I osteotomies: a prospective randomized controlled trial
Premium Wordpress Themes by UFO Themes