Chin and Malar Augmentation

Facial Plastic and Reconstructive Surgery

Module Summary

The chin complex can be important in facial symmetry and creating an aesthetically pleasing facial profile. Lateral, vertical, and transverse facial analysis can be performed. Some considerations include soft tissue position, syndromic appearance, and mandibular position. Possible procedures include chin alloplast implant, osseous genioplasty, soft tissue repositioning, and filler placement. Patient selection is often determined by anatomy.

Module Learning Objectives

Review basic anatomy as it relates to chin augmentation.
Summarize techniques and important factors in use of soft tissue filler or repositioning for chin augmentation.
Explain techniques and important factors for chin implant use.
Cite techniques and important factors for genious osteoplasty.

Anatomy

Structures of Interest

Mentalis muscle – may be hypertrophic in microgenic patients to achieve lip competence, known as “mentalis strain”
Labiomental groove
Mental foramen – inferior alveolar nerve passes through mandibular canal 2-3 mm inferior and exits foramen to become mental nerve, supplying sensation to chin and lower lip
Mandible position
- Retrognathia can be associated with horizontal chin deficiency and malocclusion (class II)
- Prognathia can be associated with horizontal chin excess and malocclusion (class III)
- Age related bony atrophy in the lower central region
Chin soft tissue
- Ptosis in aging face
  - Weakening of mentalis and depressor labii inferioris attachments
  - Soft tissue pad below mandibular line has volume loss from fat atrophy and descent
  - Creates submental horizontal crease

Facial Analysis

Syndromes/global assymetry
- Hemifacial microsomia
- Oculoauricular vertebral syndrome
Analysis methods
- Lateral analysis - cephalometric radiograph uses Frankfort horizontal where line between porion (superior EAC) and infraorbitale (inferior orbital rim) is parallel to the ground
  - Ricketts analysis
    - Tangent line placed from pogonion (most projecting part of chin soft tissue) to nasal tip
    - Upper lip 4 mm behind line
    - Lower lip 2 mm behind line
  - Steiner analysis - columellar inflection point identifies ideal chin point
  - Holdaway analysis – pogonion position relative to skeletal points of face
- Vertical analysis
  - Chin and lips should be 1/3 of facial height, measuring from subnasale to gnathion
  - Subnasale to stomion is 1/3 distance of subnasale to gnathion
  - Subnasale to vermilion border of lower lip equal to distance from vermilion border of lower lip to gnathion
- Transverse analysis
  - AP radiograph is helpful
  - Assess if chin midline corresponds to dental/upper face midline
  - May require asymmetric correction

References

Chin OY, Sykes JM. Optimizing the chin and jawline appearance: does surgery or injection make sense? Facial Plast Surg. 2019;35(2):164-171.
Sykes JM, Magill CK. Chin Augmentation. In: Johnson JT, Rosen CA, eds. Bailey’s Head and Neck Surgery. 5th ed. Philadelphia: Lippencott Williams & Wilkins; 2014.

Corrective Procedures

Alloplast placement

Patient selection
- Ideal in patients with simple horizontal deficiency/microgenia
- Can worsen existing vertical excess

Technique
- Marks for midline including thyroid cartilage, lip, chin
- Local anesthesia to chin soft tissue
- Variable incision and placement techniques exist
  - Submental incision
    - 2 cm length, 5 mm behind submental crease
    - Sharp dissection through soft tissue
    - Periosteum may be left down centrally if desired after incised vertically 2 cm lateral to midline on right and left
    - Dissection in subperiosteal plane laterally inferior to mental foramin
    - Can use implant sizer to determine size
    - May place with implant midportion supraperiosteally and lateral phalanges in subperiosteum
    - Reapproximate mentalis, soft tissue, skin
  - Alternatively, intraoral incision
    - Horizontal or vertical gingivolabial incision
    - Otherwise, identical steps
- Postoperative chin-strap dressing for three days
- Postoperative antibiotics for two days

Implant types
- Materials
  - Expanded polytetrafluoroethylene
  - Silicon rubber
  - Porous polyethylene
  - Synthetic surgical mesh
- Style
  - Button – displacement is more obvious
  - Extended/anatomical

Complications
- Hematoma
- Infection
- Dysesthesias
- Malpositioning
- Mentalis muscle dyskinesis
- Bony erosion

Genioplasty (Osseous)

History
- Hofer described in 1942
- Converse and Wood-Smith made more widespread in 1964

Patient selection
- Correction of transverse asymmetries
- Vertical and antero-posterior asymmetries

Technique
- Gingivolabial incision between canine teeth
- Dissection through and below mandibular periosteum
- Exposure of both mental nerves
- Preserve soft tissue over central mandible
- Mandibular horizontal or oblique osteotomies inferior to teeth roots and mental foramen
- Downfracture of chin
- Repositioning of segment with removal or addition of bone
- Fixation with plates, screws, or wires
- Wound closure
- Postoperative chinstrap dressing for five days
- Postoperative soft diet for two weeks

Complications
- Hematoma
- Dysesthesias
- Wound dehiscence
- Plate exposure
- Infection
- Mentalis muscle dyskinesis

Soft tissue repositioning/filler

Patient selection
- Soft tissue ptosis or deficiency
- Often done concomitantly with other procedures
- Filler for temporary change or trial

Technique
- Soft tissue repositioning
  - Remove submental skin ellipse
  - Chin soft tissue flap advanced and plicated inferiorly
- Chin filler
  - Bolus injection deep to mentalis
  - Superficial injection for mental crease

Complications
- Resorption or migration of filler
- Infection
- Soft tissue necrosis or wound dehiscence
- Hematoma or seroma

References

Chang EW, Lam SM, Karen M, et al. Sliding genioplasty for correction of chin abnormalities. Arch Fac Plast Surg. 2001;3:8-15
Chin OY, Sykes JM. Optimizing the chin and jawline appearance: does surgery or injection make sense? Facial Plast Surg. 2019;35(2):164-171.
Terino EO. Three-dimensional facial contouring: alloplastic augmentation of the lateral mandible. Facial Plast Surg Clin North Am 2002;10:249
Sykes JM, Magill CK. Chin Augmentation. In: Johnson JT, Rosen CA, eds. Bailey’s Head and Neck Surgery. 5th ed. Philadelphia: Lippencott Williams & Wilkins; 2014.

Case Studies

A 56 year old female presents for evaluation for ptosis of chin soft tissue

Submental horizontal crease is often seen due to weakening of mentalis and depressor labii inferioris attachments
Can be treated with temporary filler injection or soft tissue repositioning

A 32 year old female presents after chin alloplast placement with random muscle twitches and contractions over implant

Mentalis muscle dyskinesis can occur after implant placement with routine repositioning or displacement
Condition can be treated with 2-5 U of Botox

Review Questions

What anatomical structures must be evaluated in planning for chin augmentation surgery?
What are common methods of facial analysis that involve the chin?
What is the planned orientation and placement of a chin alloplast?
What are the steps of osseous genioplasty?
What are the usual depths of placement for chin filler?

Chin and Malar Augmentation

Chin and Malar Augmentation

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