Since genioplasty was first described in 1942 by Hofer via the extraoral approach, Trauner and Obwegeser introduced genioplasty via an intraoral approach in 1957 [1-3]. To achieve more favorable esthetic results, many surgeons have developed and modified various analyses, categories, parameters, and techniques for genioplasty. However, most technical developments include shortening, narrowing, and especially advancement of the chin, not sagittal reduction [4-7].

In the round figures, only two types of genioplasty techniques are introduced to set back the projected chin.

First was the excessive bone reduction by burr, rasp, or chisel. However, double chin and lip incompetence due to chin and lower lip drooping, and lack of cervico-mandibular definition have been reported as potential problems with this technique [1]. Most of these problems arise from the intraoral approach. Zide et al. [5] reported submental ostectomy for the surgical treatment of macrogenia with soft tissue management, including subplatysmal muscle or fat excision, and excess skin excision.

Second, a horizontal sliding osteotomy and posterior repositioning were performed. Many modifications, such as Michelet genioplasty and reduction genioplasty using wedge osteotomy have been described. However, contour irregularity at the junction between the setback segment and mandible is an unavoidable nuisance [5]. Many surgeons have attempted additional reduction or grinding of the bony step to reduce contour irregularities. However, the bony steps could not be removed perfectly, and inadequacies resulting in chin or lower lip drooping and unstable bony fixation due to lack of cortex were concerns.

The purpose of this article is to introduce a novel technique (bow-tie genioplasty) to achieve favorable sagittal reduction of the chin without the above-mentioned potential complications.

In Fig. 1, the α-angle between lines AB and A’B’ is the angle that should be added to the β angle for the pogonion setback. The amount of sagittal reduction was determined by the length of the distal segment under B’ and the α-angle. The distance from B to B’ is the required length for vertical reduction. The α-angle and vertical reduction were calculated using a lateral cephalogram or 3-dimensional (3D) computed tomography (CT).

Figure 1. Lateral diagram of the osteotomy for bow-tie genioplasty.

In Fig. 2, the highest point of the upper osteotomy line B was placed higher than the cephalometric B point if the distance from the root of the incisor was more than 5 mm. The bilateral upper osteotomy line was designed to not invade the anterior loop of the inferior alveolar nerve (IAN) around the mental foramen. The anterior loop and IAN pathway should be checked by 3D CT before surgery. The lateral endpoints of the upper osteotomy line A and C and the γ angle between AB and BC are determined by the width and shape of the chin, cephalometric B point, and roots of the lower anterior teeth.

Figure 2. Frontal diagram of the osteotomy for bow-tie genioplasty.

The lower osteotomy line (A’B’C’) was determined by the upper osteotomy line (ABC), vertical reduction (BB’), and α-angle (Fig. 1, 2).

The difference between the upper and lower osteotomy lines (ABC and A’B’C’) results in a bony step at the junction of the chin and the mandible. Additional mandibular lower border reduction surgery, minimally to the antegonial notch or extended as an angle reduction, should be followed to reduce these bony steps (Fig. 3).

Figure 3. Additional mandibular lower border reduction surgery at the junction of chin and mandible. (A) Minimal mandibular lower border reduction and (B) extended to angle reduction.

Case 1

A 25-year-old male visited our hospital for consultation with a protruding chin. The patient wanted to improve his lateral profile with minimal changes in the frontal view. The patient underwent bow-tie genioplasty with minimal additional mandibular lower border reduction (Fig. 4). Four months postoperatively, sagittal reduction of the protruded chin was achieved with minimal change in the frontal aspect (Fig. 5, 6). The patient was satisfied with the improvement in his lateral profile.

Figure 4. Three-dimensional computed tomography (CT) of a 25-year-old male with protruded chin. He underwent bow-tie genioplasty only with minimal additional mandibular lower border reduction. (A) Preoperative lateral CT and (C) postoperative lateral CT. (B) Superimposition of pre- and postoperative CT. Superimposition shows effective sagittal reduction of protruded chin.

Figure 5. A 25-year-old male with protruded chin. He underwent bow-tie genioplasty only with minimal additional mandibular lower border reduction. (A) Preoperative lateral view and (B) lateral view at 4 months after surgery. Postoperative lateral view reveals sagittal reduction of protruded chin.

Figure 6. A 25-year-old male with protruded chin. He underwent bow-tie genioplasty only with minimal additional mandibular lower border reduction. (A) Preoperative frontal view and (B) frontal view at 4 months after surgery. Postoperative frontal view reveals minimal change of frontal face.

Case 2

A 36-year old female visit our hospital complaining of a protruding chin, a square, and a wide face. She wanted to set her chin back and make her face small and smooth. The patient underwent bow-tie genioplasty, angle reduction, and cortical bone reduction surgery (Fig. 7). At 7 months postoperative follow-up, her protruded chin was set back and her wide and square face became smooth and small (Fig. 8, 9). We received the patient’s consent form about publishing all photographic materials.

Figure 7. Three-dimensional computed tomography (CT) of a 36-year-old female with protruded chin and wide face. He underwent bow-tie genioplasty, angel reduction and cortical bone reduction. (A) Preoperative lateral CT and (C) postoperative lateral CT. (B) Superimposition of pre- and postoperative CT. Superimposition shows effective sagittal reduction of protruded chin and angle reduction.

Figure 8. A 36-year-old female with protruded chin and wide face. He underwent bow-tie genioplasty, angel reduction and cortical bone reduction. (A) Preoperative lateral view and (B) lateral view at 7 months after surgery. Postoperative lateral view reveals set-backed protruded chin.

Figure 9. A 36-year-old female with protruded chin and wide face. He underwent bow-tie genioplasty, angel reduction and cortical bone reduction. (A) Preoperative frontal view and (B) frontal view at 7 months after surgery. Postoperative frontal view reveals smooth and small face.

Available literature on sagittal reduction genioplasty is scarce. Most of the developed techniques are two prementioned kinds of traditional techniques that have many potential complications or extraoral visible scars.

Bow-tie genioplasty has several advantages. This technique can achieve favorable esthetic sagittal reduction result more than previous techniques via the intraoral approach without external visible scars. Moreover, bow-tie genioplasty is not accompanied by complications, such as chin or lower lip drooping and contour irregularities. Bow-tie genioplasty can be easily modified for narrowing, shortening, lengthening, and deviation correction of the chin.

However, the bow-tie genioplasty has a disadvantage compared to the previous techniques. Bow-tie genioplasty should be accompanied by additional mandibular lower border reduction (Fig. 3). Therefore, it requires more time and effort than the previous techniques.

If the patient needed additional angle reduction, as in case 2, this additional mandibular lower border reduction was not a matter at all (Fig. 3B). However, the patient needed sagittal reduction of the protruded chin, as in case 1, and minimal mandibular lower border reduction should be performed (Fig. 3A).

Similar to traditional techniques, bow-tie genioplasty showed limited effectiveness in some patients with minimal or no labiomental fold, classified as lip-to-labiomental fold inclination type I or II. Moreover, it is a well-known negative factor for aesthetic result of reduction genioplasty [1,5].

Bow-tie genioplasty is the most innovative technique for sagittal reduction of the chin. This novel technique may optimize the chin setback effect while minimizing the complications associated with the traditional techniques.

The authors have nothing to disclose.