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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_557_Библиотеки_им_академика_М_И_Перельмана
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Operative technique
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Fig. 12.9 A subperiosteal pocket created for the placement of a
mandibular implant.
Implant positioning and fixation
To optimize desired placement, certain implants are designed with registration
tabs that align with the inferior border of the mandible (Matrix Surgical, Atlanta,
GA). To maintain desired implant position and apply it to the mandible surface
without gaps, it is fixed to the mandible with titanium screws. A long guarded
drill facilitates screw hole placement. (As originally described, self-drilling
screws were used.9 However, the author abandoned the use of self-drilling
screws because he found that the thick cortex of the mandible often made screw
penetration difficult). With vigorous retraction, implant fixation can be done
through the intraoral incision (Fig. 12.10). Clamping the implant to the mandible maintains implant position during screw fixation.
An implant used to augment only the mandibular border may have insufficient vertical height to allow screw placement from the intraoral approach. In
this case, when screw fixation is deemed critical, stab wound incisions (2 to 3
mm in length) are made in the neck skin beneath the inferior border of the mandible. A trocar and sheath can be used to protect the skin from the drill and
screw placement. This allows strategic unicortical screw fixation of the implant
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Chapter 12 Mandible
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A
Fig. 12.10 Screw xation of an implant to the mandible through an intraoral approach. (A) Artist’s depiction.
(B) Clinical photograph during mandibular augmentation. The lower lip is being retracted. The portion of the
implant augmenting the mandibular body is being exposed. Note screw xation.
B
to the mandible (Fig. 12.11). Screws are used to obliterate any gaps between the
mandible and the implant (Fig. 12.12). Screws are placed to avoid the anticipated path of the inferior alveolar nerve before its exit from the mental foramen.
Gaps may also arise when there are significant prominences on the surface of
the mandible. This is often the case at the angle of the mandible as well as at the
oblique line of the mandible body. Reduction of these prominences allows the
Fig. 12.11 Screw xation of an implant to the mandible through an extraoral
approach. A stab wound incision is made in the neck skin and telescoped
superiorly to allow axial drilling of the screw hole and screw xation of the
implant.
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posterior surface of the implant to be congruent with the anterior surface of the
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implant thereby avoiding gaps. Fig. 12.13 shows a mandible implant that was
improperly positioned or perhaps dislocated due to lack of fixation.
It is crucial to soften any transitions between the implant and the mandible,
particularly where the implant extends beyond the anterior mandibular border’s inferior edge. Any step-offs between the implant and the mandible in this
area may be visible in thin patients. Screw fixation of the implants allows scalpel
or mechanical burr final contouring with the implants in place. After hemostasis
as appropriate, the wound is irrigated (antibiotic irrigation is a rational adjunct
to decrease bacterial contamination in this operation performed through intraoral access). A suction drain with trocar travels through the skin and exits in the
postauricular area. The incision is closed in two layers with absorbable sutures.
Care is taken to evert the mucosal edges. An elastic tape dressing is used to help
apply the soft tissues to the implant and avoid hematoma formation. The suction drain usually remains until the next morning unless drainage persists.
Fig. 12.12 Screw xation applies the implant to the skeleton
and obliterates the gaps. (Gaps are equivalent to an increase in
augmentation.) (A) Sagittal view shows discrepancy in contour
between anterior surface of the mandible and posterior surface of
the implant resulting in gaps. (B) The upper screw is in place and
has xed and immobilized the implant to the skeleton. (C) The
lower screw has been placed. The posterior surface of the implant
is now congruent with the anterior surface of the mandible. The
skeleton and xed implant now reect the desired contour and
projection.
Operative technique
A B C
Video 12.1 demonstrates the placement of a mandible angle implant.
Patients are administered broad spectrum antibiotics (cephalosporins) intravenously immediately before the procedure. Oral antibiotics are administered
for 5 days postoperatively.
Fig. 12.13 CT scan demonstrates malpositioned mandible implants.
Improper implant position and postoperative implant movement
due to lack of xation may have contributed to poor outcome.
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Chapter 12 Mandible
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A liquid diet is prescribed for the first 3 days postoperatively and a soft diet
for the next 5 days. Frequent mouth washes are advised as well as very careful
tooth brushing.
Pterygomasseteric sling disruption and repair
Disruption of the pterygomasseteric sling causes the masseter muscle to retract.
Masseter retraction results in a soft tissue deficit where it had joined the pterygoid at the inferior border. The retracted muscle bulges just above the deficit
(Fig. 12.14). The resultant contour deformity can be improved. The extent of correction has depended on the chronicity of the disruption. The longer the duration of the muscle retraction, the greater the scarring causing less mobility.
11
Medial
pterygoid
Contracted
Masseter
Periosteal
tear
Periosteum
A B C
Fig. 12.14 Artist’s rendition of disruption of pterygomasseteric sling. (A) Sling intact. (B) Sling disrupted and mandible border exposed. (C)
Contraction of masseter results in bulge at mid-aspect of ramus.
masseter
Mandibular
implant
Repair can done through an internal or external approach. A subperiosteal
dissection allows identification of the retracted edge of the masseter muscle and
the inferior border of the mandible. Two or three figure-of-eight sutures purchase the inferior border of the muscle. The muscle is pulled down and sutured
to the drill holes made at the inferior border of the mandible (Fig. 12.15).
Fig. 12.15 The inferior border of the ramus and retracted edge of
the masseter has been identied through a facelift approach. The
retracted edge has been purchased with gure-of-eight sutures and
will be sewn to drill holes located at the border of the mandible.
172
CLINICAL EXAMPLES
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Clinical examples are shown in Figs. 12.16 to 12.20.
Clinical examples
A
D
Fig. 12.16 A 30-year-old male actor with normal facial dimensions and class I dental occlusion desired more “strength” to his jaw and
requested chin augmentation. After evaluation, a mandible ramus and posterior body augmentation with the implants described in Fig. 12.6
was performed as well as a tertiary rhinoplasty. (A) Preoperative frontal view. (B) Postoperative frontal view. (C) Artist’s simulation of implant
surgery – frontal view. (D) Preoperative lateral view. (E) Postoperative lateral view. (F) Artist’s simulation of implant surgery – lateral view.
B
E
C
F
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Chapter 12 Mandible
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A
D
Fig. 12.17 A 21-year-old woman who had undergone orthodontic correction of her class II malocclusion desired improved nasal and
mandibular contour. Rhinoplasty and mandibular augmentation with mandibular ramus and body implants as well as an extended chin
implant were undertaken. (A) Preoperative frontal view. (B) Postoperative frontal view. (C) Artist’s simulation of implant surgery – frontal view.
(D) Preoperative lateral view. (E) Postoperative lateral view. (F) Artist’s simulation of implant surgery – lateral view.
B
E
C
F
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Clinical examples
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A
D
B
E
C
F
Fig. 12.18 A 35-year-old male had ve previous chin operations. He desired a very strong mandible. A silicone chin implant was removed.
A 9-mm porous polyethylene chin implant and a mandibular angle implant were placed. The chin pad was resuspended. (A) Preoperative
frontal view. (B) Preoperative lateral view. (C) Preoperative oblique view. (D) Postoperative frontal view. (E) Postoperative lateral view. (F)
Postoperative oblique view.
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Chapter 12 Mandible
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Fig. 12.19 A 30-year-old man with
Treacher–Collins syndrome underwent
advancement sliding genioplasty as an
adolescent. A 9-mm porous polyethylene
chin implant and mandibular implants were
placed. (A) Preoperative frontal view. (B)
Preoperative lateral view. (C) Preoperative
oblique view. (D) Postoperative frontal
view. (E) Postoperative lateral view. (F)
Postoperative oblique view.
A
B
D
E
C
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F
A B
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References
C
D
Fig. 12.20 A 24-year-old woman underwent chin and mandible augmentation. (A) Preoperative frontal view. (B) Postoperative frontal view.
(C) Preoperative oblique view. (D) Postoperative oblique view.
REFERENCES
1. Farkas LG, Hreczko TA, Katic MJ. Craniofacial norms in North American Caucasians from
birth (one year) to young adulthood. In: Farkas LG, editor. Anthropometry of the head and
face. 2nd ed. New York: Raven Press; 1994.
2. Bell WH, Proffit WR, Chase DL, Wickwire NA, Poultom DR. Mandibular deficiency. In: Bell
WH, Proffit WR, White RP, editors. Surgical correction of dentofacial deformities, vol. 1.
Philadelphia: Saunders; 1980.
3. Semergidis TG, Migliore SA, Sotereanos GC. Alloplatic augmentation of the mandibular angle.
J Oral Maxillofac Surg 1996;54(12):1417–23.
4. Terino EO. Alloplastic facial contouring: surgery of the fourth plane. Aesthetic Plast Surg
1992;16(3):195–212.
5. Terino EO. Unique mandibular implants, including lateral and posterior angle implants. Facial
Plast Surg Clin North Am 1994;2:311–28.
6. Whitaker LA. Aesthetic augmentation of the posterior mandible. Plast Reconstr Surg
1991;87(2):268–75.
7. Aiche AE. Mandibular angle implants. Aesthetic Plast Surg 1992;16(4):349–54.
8. Taylor CO, Teenier TJ. Evaluation and augmentation of the mandibular angle region. Facial
Plast Surg Clin North Am 1994;2(3):329–37.
9. Ramirez OM. Mandibular matrix implant system: a method to restore skeletal support to the
lower face. Plast Reconstr Surg 2000;106(1):176–89.
10. Yaremchuk MJ. Mandibular augmentation. Plast Reconstr Surg 2000;106(3):697–706.
11. Thomas MA, Yaremchuk MJ. Masseter muscle reattachment after mandibular angle surgery.
Aesthet Surg J 2009;29(6):473–6.
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