**9. Complications**

#### **9.1. Improper selection or placement**

Improper placement of the implant is the most common complication followed by improper implant selection. The implant should be slightly smaller than the desired increase in fullness. Selecting too large an implant will lead to excessive soft tissue tension, which could lead to ischemia, necrosis, or extrusion. Placement of malar implants too laterally can cause the eyes to look too close together. Placement of the implants too medially and inferiorly will give a chipmunk look or appearance.

#### **9.2. Neuropraxia**

Neuropraxia can occur from impingement of the nerve by a large implant, migration or improper placement of the implant, a traction injury, a thermal injury, or a direct traumatic injury from dissection. Most patients regain sensation and function within three weeks. Dissection for Malar implants involves elevating tissue around the infraorbital nerve. Weak‐ ness of the zygomaticus, orbicularis oculi, or the frontalis muscles can be induced by disturb‐ ance of the temporofrontal branch of the facial nerve while dissecting posteriorly over the middle third of the zygomatic arch. Straying from the subperiosteal plane predisposes to dissection into the parotid and facial nerve branches and facial musculature. During dissection of the chin, it is important to avoid the mental nerve, which is approximately underneath the area of the premolars intraorally. The marginal mandibular branch of the facial nerve, which supplies muscles of the lower lip and chin, is above the periosteum over the inferior border of the mandible. A severe traction injury or perforation of the periosteum can injure the marginal mandibular branch of the facial nerve.

#### **9.3. Edema and ecchymosis**

The majority of postoperative edema and ecchymosis resolves in two weeks, but edema can persist for 6 months and even up to a year [46]. Implant fixation is important because excessive continuing movement can cause tissue injury, chronic inflammation, and suboptimal soft tissue acceptance with prolonged edema. This could also be due to a nonspecific immune reaction to the implant material.

#### **9.4. Hematoma and seroma**

Abnormal fluid collection can be the result of inadequate hemostasis, over-dissection, trau‐ matic handling of the tissues, dead space around or underneath the implant or elevated blood pressure. Hematomas and seromas encourage the growth of bacterial contamination potenti‐ ating cellulitis and infection. They can result in excessive fibrosis producing soft tissue defects. Smaller hematomas (<5 cc) resolve without treatment in 10–14 days. Large hematomas need to be recognized and evacuated with the implant removed as necessary. Seromas usually present around 2 weeks after surgery. Presence of liquefied hematomas or seromas 2 to 4 weeks postoperatively may be drained percutaneously [47].

#### **9.5. Infection**

**9. Complications**

**9.1. Improper selection or placement**

562 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

chipmunk look or appearance.

mandibular branch of the facial nerve.

**9.3. Edema and ecchymosis**

reaction to the implant material.

postoperatively may be drained percutaneously [47].

**9.4. Hematoma and seroma**

**9.2. Neuropraxia**

Improper placement of the implant is the most common complication followed by improper implant selection. The implant should be slightly smaller than the desired increase in fullness. Selecting too large an implant will lead to excessive soft tissue tension, which could lead to ischemia, necrosis, or extrusion. Placement of malar implants too laterally can cause the eyes to look too close together. Placement of the implants too medially and inferiorly will give a

Neuropraxia can occur from impingement of the nerve by a large implant, migration or improper placement of the implant, a traction injury, a thermal injury, or a direct traumatic injury from dissection. Most patients regain sensation and function within three weeks. Dissection for Malar implants involves elevating tissue around the infraorbital nerve. Weak‐ ness of the zygomaticus, orbicularis oculi, or the frontalis muscles can be induced by disturb‐ ance of the temporofrontal branch of the facial nerve while dissecting posteriorly over the middle third of the zygomatic arch. Straying from the subperiosteal plane predisposes to dissection into the parotid and facial nerve branches and facial musculature. During dissection of the chin, it is important to avoid the mental nerve, which is approximately underneath the area of the premolars intraorally. The marginal mandibular branch of the facial nerve, which supplies muscles of the lower lip and chin, is above the periosteum over the inferior border of the mandible. A severe traction injury or perforation of the periosteum can injure the marginal

The majority of postoperative edema and ecchymosis resolves in two weeks, but edema can persist for 6 months and even up to a year [46]. Implant fixation is important because excessive continuing movement can cause tissue injury, chronic inflammation, and suboptimal soft tissue acceptance with prolonged edema. This could also be due to a nonspecific immune

Abnormal fluid collection can be the result of inadequate hemostasis, over-dissection, trau‐ matic handling of the tissues, dead space around or underneath the implant or elevated blood pressure. Hematomas and seromas encourage the growth of bacterial contamination potenti‐ ating cellulitis and infection. They can result in excessive fibrosis producing soft tissue defects. Smaller hematomas (<5 cc) resolve without treatment in 10–14 days. Large hematomas need to be recognized and evacuated with the implant removed as necessary. Seromas usually present around 2 weeks after surgery. Presence of liquefied hematomas or seromas 2 to 4 weeks Implants can be contaminated by hematogenous, contiguous spread, or direct inoculation. Foreign bodies have been shown to reduce the number of bacteria required to produce an infection by 104 to 106 power [48]. Chemical composition, surface roughness, surface config‐ uration, and hydrophobicity influence the potential for implant contamination. Hydrophilic materials are more resistant to adhesion than hydrophobic materials. Scalfani and colleagues found that PTFE with an average pore size of 22 microns became infected at lower inoculum counts and sooner than polyethylene with a pore size of 150 microns [48]. Most infections in the early postoperative time period are more likely to occur with porous implants because of increased surface area, irregularity, and surface energy, which facilitates bacterial adherence. Infections that occur years after surgery are most probably caused by hematogenous spread or direct violation of the implant capsule with bacterial seeding like an injection. Late malar implant infections have been associated with dental injections as reported by Cohen and Kawamoto [49].

S. aureus is the main pathogen and is usually susceptible to penicillin or cephalosporin. A better chance of eradicating the infection with antibiotics and drainage is possible with nonporous implants. In the presence of a purulent infection, the implant should be removed and scrubbed and sterilized to remove the biofilm. In addition, debridement and copious irrigation of the implant pocket and a prolonged postoperative antibiotic course are necessary. If rapid improvement does not occur and the implant needs to be removed, it should not be replaced for 6–8 weeks to allow for resolution of the infection and inflammation [50].

#### **9.6. Migration and contour changes**

Migration is usually the result of over dissection, improper implant size selection and lack of fixation. Supraperiosteal placement can predispose the implant to mobility especially without adequate fixation. Anatomic implants have decreased the potential for migration, rotation, and displacement. Delayed contour changes have been reported in association with silastic implants. This is thought to be associated with capsular contracture around the implant in addition to calcification of the capsule itself.

#### **9.7. Extrusion**

Adequate soft tissue bulk with good quality tissue for coverage of the implant and tensionfree correct plane insertion are critical to preventing implant extrusion. Decreased tissue perfusion causes wound healing problems. Highly scarred and thinned tissues tend to atrophy over time and are at a higher risk for postoperative infection, exposure, and extrusion [35]. Excessive tension is a result of placing too large an implant in a small pocket. In addition to tension free closure, subperiosteal placement helps prevent exposure.

#### **9.8. Palpability**

This can be the result of improper implant size selection, improper contour selection, improper positioning, improper fixation or capsular contracture. Thin overlying tissue and supraper‐ iosteal placement of the implant predispose to palpability.

#### **9.9. Lip dysfunction**

Altered lip function occurs because dissection can interfere with the muscles responsible for smiling mimetics. Other factors include edema, interposition of a solid implant which stretches the muscles of the midface, or interference with the facial nerve during dissection over the zygomatic arch. The edema can cause dysfunction in the muscles of the lips resembling facial nerve dysfunction. When dysfunction is due to muscle displacement, it usually takes 1–3 months for the muscles to reattach and the capsule to become soft and distensible.

#### **9.10. Bone resorption**

Bone erosion under alloplastic implants was a significant problem with early implants. It was often attributed to foreign body reaction between the implant and the bone or to pressure from the mentalis muscle against the implant. Improper implant positioning, pressure due to an oversized implant, subperiosteal placement and hardness of the implant were also considered.

The resorption from anatomic malar and chin implants is minimal and self-limiting. Bone erosion occurs less with anatomic extended implants because of greater distribution of the pressure forces over a broader anatomic area. Resorption appears to occur in the first 12 months after placement but can appear radiographically as soon as 2 months. Labial incompetence and hyperactive mentalis lead to pressure and migration of the implant superiorly onto the thinner bone of the alveolus, which predisposes to resorption. When severe resorption is present, the implant must be removed.

#### **9.11. Postoperative asymmetry**

Asymmetry is more likely to be noticed in malar implants. It is usually caused by initial malposition or by creation of asymmetric bilaterally dissected spaces. It can also be the result of unrecognized preoperative skeletal or soft tissue deficiencies. It is important to point out preexisting asymmetry before treatment selection. Although major asymmetries require a second surgery, minor asymmetries have a natural tendency to adjust and correct themselves over a 6-month postoperative period as healing progresses and the tissue around the implant relaxes and softens.

## **10. Summary**

Loss of volume and volume shift occur in all regions of the face and neck and contribute to the aged appearance. Volume replacement and contour augmentation of the face are the essentials of facial cosmetic surgery. The development of less invasive volume replacement procedures has been an evolution in achieving better aesthetic results. These procedures include lifting procedures, injectable fillers, autologous fat transfer, and facial implants.

Facial volume augmentation by using facial implants is a very safe procedure that is used widely for facial rejuvenation which can be used concomitantly with other rejuvenation procedures. It is crucial for the cosmetic surgeons to be familiar with various implant materials and their advantages and disadvantages.
