There is no argument that recent innovations in the diagnosis and management of disease involve the application of technology. However, can some of the complementary technological advancements and gadgets that have become lifestyle necessities actually cause disease themselves? Blackberry thumb, iPad finger, and tech neck are becoming the common new ailments compromising our work, activities of daily living, and perhaps even our appearance.
Mucosal incision (Image source: oralhealthgoup.com)
Smartphone face1 is the phenomenon that describes how sitting for hours with your head tipped forward staring at a smartphone, laptop or computer screen, will shorten the neck muscles and increase gravitational pull on the lower face and chin. This leads to submental fullness, double chin (buccula), facial sagging (jowls) and a recessive chin profile (microgenia). The development of the symptoms characterizing smartphone face can be attributed to genetics, the natural aging process and weight fluctuation; nevertheless, the explosion in the use of electronic gadgets has mirrored the rise in individuals seeking treatment of the chin.
According to the American Society of Plastic Surgeons the number of chin augmentation surgeries performed in the United States increased over 70 percent in 2011.2 This increase is more than breast augmentation, botox and liposuction. With equal numbers of both men and women opting for the procedure, it makes chin augmentation the fastest growing plastic surgery trend.3 A trend that is expected to continue as facial aging may first appear in the chin and jaw line. The posting of pictures on Facebook and Instagram and the increasing prevalence of video chat technology, like Skype and FaceTime where perceived flaws are instantly captured for all to see, may be driving force behind the escalating numbers.4 Many people are seeking ways to improve their appearance, boost self-confidence and provide themselves any competitive advantage in the workplace.
THE COSMETIC SURGERY PERSPECTIVE - AUGMENTATION
The chin forms an integral part of the total facial esthetic and profile. A visual treatment objective is developed from a lateral cephalometric tracing and a systematic clinical patient evaluation.5 Esthetic considerations of the lower facial third requires attention to vertical dimension, symmetry and profile to achieve facial balance with the forehead, cheeks, paranasal area, lips and neck.6 Many patients that present for nasal surgery, only after consultation, realize that adding a chin augmentation can improve their overall facial balance and appearance in profile.2
Cosmetic chin augmentations, whether performed by an otolaryngologist or a plastic surgeon, most frequently incorporate the use of an alloplastic implant. Chin implants can be silicone, polymethacrylate, polyethylene or expanded polytetraflourethylene.7 The procedure is performed by an extraoral submental approach as the chin implant is often combined with cervicofacial liposuction, platysma plication (necklift) or rhytidectomy (facelift) through the same skin access incision.6 The implants can be biocompatible, easy to contour, place and remove if necessary.
Injectable facial volumizing fillers including hyaluronic acid (Restylane, Juvederm) and calcium hydroxylapatite (Radiesse) are being used to temporarily augment the chin. The effects can last up to a year and allow an idea of what a chin implant may more permanently provide.2
The use of chin implants is low risk but is not without complication. Alloplastic materials may result in unpredictable soft tissue contours, resorption of bone and sometimes underlying tooth roots, palpable mobility, infection and inflammatory foreign body reactions.5
THE ORAL SURGERY PERSPECTIVE - ADVANCEMENT
Preoperative radiograph (Image source: oralhealthgroup.com)
Chin augmentations performed by an oral and maxillofacial surgeon most frequently involve a sliding bony advancement by genioplasty. The genioplasty is a horizontal osteotomy of the mandibular symphysis. Originally described from an extraoral approach,8 it is almost exclusively performed today by intraoral access.9 Although a genioplasty can be an isolated procedure, an oral surgeons participation is usually to complement other orthognathic surgical procedures required to correct a malocclusion. Unlike cosmetic implant augmentation, the bony chin advancement not only affords an esthetic change but can provide functional objectives. Genioplasty advancement of the genial tubercle and genioglossus muscle is used to treat sleep apnea.6 Lip competency can be improved by incorporating a vertical chin reduction with the horizontal advancement. In variation, the genioplasty can be used to improve almost every skeletal abnormality of the chin. An excellent review on the preoperative radiographic assessment and clinical patient evaluation was previously published in Oral Health.5 Since this article is on chin augmentation; we are limiting the discussion to our genioplasty advancement technique. Potential complications are addressed at each step to minimize their development.
GENIOPLASTY ADVANCEMENT TECHNIQUE
In the oral surgery environment, since chin advancement is often combined with a LeFort I or a mandibular bilateral sagittal split osteotomy, a general anesthetic is used. However, it can be performed independently on an outpatient basis under sedation and local anesthesia.10 A local anesthetic with vasoconstrictor is injected submucosally along the symphysis to the gonial notch bilaterally. The lower lip is retracted and a superficial mucosal incision is made 1 cm anterior to the depth of the labial vestibule from cuspid to cuspid (Fig. 1). This incision may allow identification of the mental nerve branches.6 An incision placed too close to the vestibule can result in scar bands and unaesthetic mucosal webbing. The incision is then angled directly to the labial cortical bone through the mentalis muscle and periosteum. The soft tissue is reflected superiorly and inferiorly to expose the intended level of the osteotomy. Lateral dissection identifies the mental foramina bilaterally and then extends posteriorly to the inferior aspect of the mandibular body.
A midline vertical line is marked into the labial cortex perpendicular to the planned horizontal osteotomy (Fig. 2). A failure to preoperatively assess and mark the facial and dental midline can lead to transverse malposition and asymmetry. The horizontal osteotomy is made approximately 5 mm inferior to the mental foramen with a reciprocating saw cutting cross-table from the posterior to the midline, through both labial and medial cortices (Fig. 3). The mental nerves are carefully protected as the osteotomy is performed. Poor exposure, excessive retraction or inadequate protection are the most common causes of nerve injury.11 In one study,12 although postoperative sensory loss was found temporarily in all patients, normal sensation returned within 12 months. The posteromedial aspect is the most problematic area to cut. A retractor is placed under the inferior border of the mandible to protect the facial artery and vein. If the posterior osteotomy is not confirmed, an unfavorable fracture of the inferior border of the mandible distally may occur.11 Mobilization of the inferior free chin segment is accomplished (Fig. 4) and is anteriorly repositioned to the predetermined advancement.
Stabilization can be made with cortical or circumferential stainless steel wires, titanium miniplates or screws. Our preferred stabilization method involves rigid fixation using two interosseous titanium screws and a lag screw technique. A 1.5 mm hole is drilled in a superior and posterior direction, engaging both the labial cortex of the inferior free chin fragment and the medial cortex of the superior tooth-bearing segment. The labial cortex is countersunk to reduce postsurgical screw palpation and enlarged to the same 2.0 mm diameter of the fixation screw itself. The screw threads do not engage the chin fragment as the screw is placed and tightened (Fig. 5). This technique provides rigid fixation with mild compression (Fig. 6). Titanium screws osseointegrate and rarely need removal. Inadequate stabilization of the mobilized chin fragment may lead to malposition, asymmetry or bony nonunion. Rigid internal fixation promotes maintenance of the advancement and minimal relapse is reported.10 The ratio of soft tissue change to amount of bony movement associated with a surgical genioplasty advancement is predictable and close to 1:1. There is a bony remodeling or rounding of the posterior wings and osteotomy step of the advanced segment that occurs with time.
Posoperative radiograph (Image source: oralhealthgroup.com)
Initial soft tissue closure involves the mentalis muscles bilaterally and the mucosal midline is identified and a resorbable suture is placed to coordinate symmetry. The mucosal layer is then closed in a running fashion (Fig. 7). A layered closure, midline identification and muscle reapproximation helps to obtain optimal chin and lip position.11 An Elastoplast chin pressure dressing is applied for 48 hours to minimize hematoma formation and to help support the suture line. A comparison of the preoperative and postoperative radiographs confirms the bony and soft tissue advancement and improved lip competency provided by genioplasty (Figs. 8, 9).
Chin augmentation can be performed competently by a number of specialties, each of which employs their preferred technique. It appears the patterns for referral may be based on whether a patient’s evaluation determines the need for primarily an esthetic change or there are also functional objectives. The desired treatment goals can be achieved and complications minimized with systematic clinical and radiographic evaluation, careful surgical technique and consideration of the anatomy of the area.
Dr. Domenick Coletti, a Maryland-based surgeon, performs a number of maxillofacial and oral surgical procedures, including chin surgery. Visit this website for more information.
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