Chin ptosis is described as a descent of the soft tissue from the symphyseal region to a position under the lower contour of the mandible. Given its multifactorial causes, treatment must be determined on a patient-by-patient basis. While augmentation of the submental crease is a versatile option for the correction of chin ptosis, this only corrects the soft tissue component. A technical modification to treat dynamic chin ptosis, associated with bone reduction in the mandibular symphysis, is presented here.
Chin ptosis is described as a descent of the soft tissue from the symphyseal region to a position under the lower contour of the mandible . In contrast to the case of witch’s chin, the tissue is projected downward, not outward . Chin ptosis can be seen in patients of all ages, although it is usually associated with aging.
According to Garfein and Zide , there are four types of chin ptosis: illusory, developmental, iatrogenic, and dynamic. The latter of these causes an effacement and drop of the chin pad soft tissues in patients with a horizontal smile without commissure elevation. This can be seen in patients with a greater predominance of the actions of the risorius muscle (which has a horizontal vector) over the zygomaticus major and minor muscles (which have a commissural ascent vector). Thus, upon smiling the soft tissue is compressed against the symphyseal bone prominence, causing the chin tissue to drop. It can present in patients who have undergone surgical interventions (as a side-effect of genioplasty reduction, among others), as well as in those who have not. Given its multifactorial causes, treatment must be determined on a patient-by-patient basis.
This technical note presents a modification of the technique presented by Lesavoy et al. , in which an osteotomy is also performed on the mandibular symphysis to treat dynamic chin ptosis associated with macrogenia ( Fig. 1 ).
A horizontal ellipse is drawn on the skin using a skin marker, with the main axis aligned with the submental crease. Between 3.6 ml and 5.4 ml of local anaesthetic is infiltrated subcutaneously into the demarcated area. Next, using a scalpel, an incision is made in the demarcated area to eliminate the skin and subcutaneous tissue and reach the plane of the platysma muscle. After this, a skin marker is used to mark the muscular tissue of the platysma with two anterior-base triangles. A third posterior-base triangle is formed between the two that have already been described. This central triangle of the platysma muscle is resected and eliminated ( Fig. 2 ). Next, the central part of the area is dissected in search of the bone plane of the edge of the mandible. A 4-mm incision is made on the mentalis muscle above its lower insertion, leaving sufficient remaining muscle tissue so that they can be repositioned and sutured after having been detached. The inferior border of the mandible is exposed and the dissection is completed in a sub-periosteal plane. An ostectomy is performed on the pogonion using a surgical hand-piece and bur, under abundant irrigation with physiological saline solution ( Fig. 3 ). The surgical field is then cleaned, the mentalis muscle repositioned, and the area sutured using Vicryl 4–0 (Ethicon). The vertices of the two triangles are connected in a convergent manner, and the platysma muscle sutured with interrupted Vicryl 4–0 stitches. Next the medial edges of the two triangles are brought together using the same suture material. Lastly, plane suturing is undertaken, which repositions the subcutaneous tissue towards the back, correcting the defect and facilitating suturing without tautness of the skin; this is done in a continuous fashion using Prolene 6–0 (Ethicon) ( Fig. 4 ).