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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5208_Библиотеки_им_академика_М_И_Перельмана
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Mandible Trauma Reconstruction
23
AryaNamin andUgochukwuUmeh
Introduction
In the current era, most mandibular fractures are sustained in motor vehicle collisions, although interpersonal violence is the most common etiology in some series
[1, 2]. While the incidence of mandibular fractures has certainly increased with the
advent of the motor vehicle, these injuries have been a challenge to humans for millennia. In ancient times, mandible fractures were considered untreatable and fatal
injuries, likely due to infection and the functional impairment of untreated fractures
[3]. Hippocrates is one of the rst physicians to attempt the treatment of mandible
fractures [3, 4]. Hippocrates described a method of closed reduction, interdental
xation with gold wires, and external leather straps to help keep the mandible in
reduction [3, 4]. Little changed in the management of mandibular fractures until the
eighteenth century when dental splints were rst described in the management of
mandibular fractures. The nineteenth century saw the advent of attempts at open
reduction with internal xation via wires as well as the rst descriptions of maxillomandibular xation [3, 5]. Thomas Gunning was amongst those who described
maxillomandibular xation through interdental splinting, and a modication of the
Gunning splint is still an option in the management of edentulous patients today [6].
It was at the turn of the twentieth century that immobilization of mandibular fractures with plates and screws was rst described [3, 5]. During the 1960s, widespread
production of these plates and screws began, allowing for this technique to be more
widely utilized [3, 5].
The objectives of mandibular trauma reconstruction are restoring the premorbid
form and function of the mandible. This requires fracture reduction while in
A. Namin (*)
Otolaryngology and Facial Plastic Surgery Associates, Fort Worth, TX, USA
U. Umeh
Medical University of Lublin, Lublin, Poland
© The Author(s), under exclusive license to Springer Nature
Switzerland AG 2024
F. Sokoya, A. G. Vincent (eds.), Manual of Head and Neck Reconstruction,
https://doi.org/10.1007/978-3-031-65999-7_23
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premorbid occlusion with adequate xation to allow for bone healing. Depending
on patient characteristics, fracture location, concomitant craniomaxillofacial injuries, and severity of fracture displacement, the treatment required to achieve these
goals can range from observation and soft diet to open reduction and internal xation with load-bearing reconstructions. In this chapter, the various reconstructive
options for condylar, ramus, angle, body, symphyseal, and parasymphyseal fractures will be discussed.
A. Namin and U. Umeh
Anatomy
The mandible consists of the condylar process, coronoid process, ramus, angle,
body, symphysis, parasymphysis, and alveolar process [7–10]. The symphysis is the
area of bone below the roots of the central incisors, and the parasymphysis is the
area of bone below the roots of the lateral incisors and canines [8]. The mandibular
body is the area of bone lateral to the canine and medial to the third molar [8]. The
angle and ramus of the mandible extend from a vertical line behind the third molar
to the outer mandibular angle posteroinferiorly and to the mandibular notch and
bases of the condylar and coronoid processes superiorly [8]. The condylar head
articulates with the glenoid fossa of the temporal bone. The condylar and coronoid
processes are separated by the mandibular notch. The condylar process continues
superiorly from the posterior border of the ascending ramus and can be broken
down into the condylar head, neck, and base [9]. The lateral pterygoid inserts onto
the pterygoid fovea of the condylar neck. The masseter and medial pterygoid muscles form a sling around the ramus and angle. The temporalis muscle inserts into the
coronoid process of the mandible. On the medial surface of the ramus, the inferior
alveolar neurovascular bundle enters the mandibular foramen. The mylohyoid
groove begins immediately anterior to the mandibular foramen and then travels
along the medial surface of the mandibular body. The mental foramen is found at the
level of the second premolar or at the interspace of the premolars.
Indications/Contraindications
Symphysis andParasymphysis
Symphyseal and parasymphyseal fractures typically require surgical treatment. In
nondisplaced and immobile fractures, no-chew diet can be considered. Surgical
treatment options for noncomminuted symphyseal and parasymphyseal fractures
include closed reduction with maxillomandibular xation, two-miniplate xation,
single thicker reconstruction plate xation, lag screw xation, and dynamic compression plate xation (Fig.23.1) [11]. Closed reduction with maxillomandibular
xation avoids the risks of internal xation with open reduction. However, it does
necessitate a prolonged period of immobilization, thus placing the patient at risk for
malnutrition and temporomandibular joint dysfunction. When utilizing open
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23 Mandible Trauma Reconstruction
Fig. 23.1 Symphyseal fracture xated with a 2-mm thick locking plate along the inferior border
of mandible with the two bicortical screws on each side of the fracture line and a miniplate superior
to this with two monocortical screws on each side of the fracture line. The 2mm thick plate along
the inferior border was chosen due to the patient presenting 8weeks after the initial injury with a
concomitant infection that required treatment prior to the patient undergoing denitive repair
307
reduction internal xation, the patient should be temporarily placed in maxillomandibular xation to ensure premorbid occlusion. The advantages of miniplates are
ease in bending the plates to the appropriate contour of the mandible and, therefore,
improving the efciency of the surgery. Excellent functional results with minimal
complications have been obtained with the application of two 1-mm thick miniplates and monocortical screws in the treatment of noncomminuted symphyseal and
parasymphyseal fractures [11]. Lee etal. recommends prescribing a soft diet for
6 weeks after treatment of symphyseal and parasymphyseal fractures with two
miniplates and only leaving patients in maxillomandibular xation if the presence
of other craniomaxillofacial injuries necessitated this [11]. Locking plates provide
potential advantages of less screw loosening, greater stability, and less precise bending of the plate because of the internal/external xator principle [12]. However,
locking plates are more expensive, and a prospective trial comparing locking plates
to standard plates did not nd any signicant difference in short-term complication
rates [12]. Lag screw xation has been found to have similar outcomes as plate xation; however, this technique is associated with more intraoperative challenges in
obtaining proper xation [13].
Body
Mandibular body fractures commonly require treatment. In nondisplaced and
immobile fractures, a soft diet can be considered. Surgical treatment options for
mandibular body fractures include closed reduction with maxillomandibular xation, two-miniplate xation, single thicker reconstruction plate xation, and
dynamic compression plate xation. The application of a miniplate inferiorly with
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A. Namin and U. Umeh
bicortical screws and a miniplate superiorly with monocortical screws offers a stable repair obviating the need for postoperative maxillomandibular xation [14]. The
plate thickness and need for bicortical screws is a debatable topic. However, a prospective study has found equivalent rates of fracture healing in patients treated with
thicker plates and bicortical screws and patients treated with thinner plates and
monocortical screws [15]. In sagittally and obliquely oriented fractures of the mandibular body and ramus, lag screws can offer a good option for repair. If lag screws
are utilized, at least two need to be placed in order for the repair to be stable.
Compression plate xation is less commonly utilized due to the unforgiving nature
of these plates. However, they have been successfully used in atrophic mandibles,
for which they were originally described [16]. In comminuted fractures and fractures with devitalized bone, a load-bearing reconstruction must be undertaken with
at least three bicortical screws on each side of the fracture (Figs.23.2 and 23.3) [17].
In cases where the devitalized bone is removed, resulting in an intervening gap, cellular bone matrix (ViviGen® Cellular Bone Matrix DePuy Synthes Companies),
autogenous bone grafting, or free tissue transfer should be employed to help prevent
nonunion (Figs.23.4 and 23.5) [17, 18].
Angle andRamus
Because of the forces of mastication, angle fractures have the highest risk of postsurgical complications, including infection [14, 19, 20]. Management of third
molars in mandibular angle fractures is a debatable subject and likely a contributing
factor to the increased complication rate seen in these fractures [19, 21]. When the
root is fractured, unsalvageable teeth due to caries or infection, unstable or loose
teeth, and teeth preventing adequate fracture reduction are considerations for
Fig. 23.2 Mandible
fracture after gunshot to
the face with comminution
and partial thickness
continuity defect along the
inferior border of the
mandible
R
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23 Mandible Trauma Reconstruction
Fig. 23.3 Mandibular
body and parasymphysis
exposed. Bone fragments
have been removed,
resulting in a partial
thickness continuity defect
along the inferior border of
the mandible
Fig. 23.4 Fixation of
fracture with 2.5mm thick
reconstruction plate. Three
bicortical locking screws
are present on each side of
the partial thickness
continuity defect
309
extraction [20, 21]. Treatment options for angle fractures include maxillomandibular xation, two-miniplate xation, three-dimensional square or rectangular-shaped
miniplate xation, and single miniplate xation along the superior border of the
mandible [19, 20, 22, 23]. In a prospective study examining the outcomes of angle
fractures treated with either maxillomandibular xation, single miniplate xation,
or two-miniplate xation, it was found that the application of a single miniplate
offered the shortest operative time with signicantly fewer postoperative complications [19]. The advantages of the single miniplate technique along the oblique line
of the mandible include decreased operative times, avoidance of transbuccal trocar
placement, and avoidance of elevating the periosteum along the ramus and angle
[19, 20]. However, there is some concern that the single superior miniplate provides
inadequate xation along the inferior mandibular border during functional loading,
leading some surgeons to utilize either two miniplates or three-dimensional box
plates [21, 24]. In a series of 88 patients with mandibular angle fractures treated
with two-miniplate xation using monocortical screws, the complication rate was
minimal, and the infection rate was 2.9% [21].
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Fig. 23.5 Partial thickness
continuity defect
reconstructed with cellular
bone matrix (ViviGen®
Cellular Bone Matrix
DePuy Synthes
Companies)
A. Namin and U. Umeh
Condylar
The management of condylar fractures varies signicantly amongst institutions and
surgeons. Over the past few decades, our understanding of the biomechanics of the
temporomandibular joint and the biological adaptations that occur with the masticatory system after condylar fractures has signicantly improved, allowing for better,
albeit still controversial, treatment plans [25]. Management options for these fractures include closed treatment, open treatment, and endoscopic treatment options.
Closed treatment options include a soft diet, jaw exercises, maxillomandibular xation with elastics, and maxillomandibular xation with wires. In the closed treatment of condylar process fractures, it is accepted that a degree of malunion will
occur and that the patient will have a good outcome due to remodeling that occurs,
allowing for a functional neoarticulation [25, 26]. Condylar fractures are the most
common pediatric mandibular fracture, and closed treatment has been found to have
good outcomes in these cases [27, 28]. Open approaches include the preauricular,
retromandibular, and submandibular approaches, with the goal of placing at least
one miniplate with two monocortical screws on each side of the fracture line. The
endoscopic approach also has the same xation goals as the open approach but utilizes a transoral approach with endoscopic assistance for visualization and typically
requires a small facial incision for a transbuccal trochal that allows for screw placement [28–30]. The objectives of treatment include restoring premorbid occlusion,
pain-free mouth opening with an interincisal distance of 40mm, facial symmetry,
sound temporomandibular joint function, and normal movement of the jaw in all
directions [31]. The surgeon must, therefore, assess the characteristics of the condylar fracture and associated craniomaxillofacial injuries to develop an optimal treatment plan for that patient. In the 1980s, Zide and Kent proposed that displacement
of the condyle into the middle cranial fossa, difculty in obtaining occlusion with
closed reduction, lateral displacement of the condyle, and presence of a foreign
body in the condylar neck were absolute indications for open reduction internal
xation [31, 32]. However, since that time, the indications for open reduction internal xation of condylar fractures have expanded, given the unfavorable outcomes in
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certain patients treated with closed approaches [29–31, 33]. Patients who can
achieve good outcomes with closed treatment approaches include those with less
than 2mm of shortening of the height of the ramus and less than 10 degrees of
deviation [30, 31]. Patients whose outcome would be improved with open or endoscopic reduction with internal xation include those with more than 15mm of shortening of the height of the ramus or more than 45 degrees of deviation [30, 31].
Patients with temporomandibular joint dislocation and associated midfacial or panfacial fractures also likely benet from open reduction internal xation [31]. In
order for the patient to undergo successful internal xation, there must be adequate
bone in the segment proximal to the fracture line to allow for two screws to be
placed. In cases where there is inadequate bone stock in the proximal segment for
two screws, external xation is an option [34]. For patients with 2–10mm of shortening of the height of the mandible and 10–45 degrees of displacement, the optimal
treatment option is less clear [30, 31].
Preoperative Planning
Patients who present with acute mandibular fractures, particularly those involved in
motor vehicle collisions, have commonly been involved in a high energy crashes
and, therefore, should be evaluated according to advanced trauma life support protocols in order to identify and intervene on any acutely life-threatening injuries. A
history regarding the mechanism of the injury should be inquired. Prior history of
trauma, craniomaxillofacial surgery, bone diseases such as osteoporosis, and temporomandibular joint dysfunction should be elicited. Prior medical and psychiatric
history should be obtained. Individuals with epilepsy may not be good candidates
for postoperative maxillomandibular xation. Current medications, prior surgeries,
and allergies should be documented. Social history, such as alcohol intake and
methamphetamine use, are also important preoperative considerations. After the
trauma exam has been completed, tell-tale signs of craniomaxillofacial trauma are
typically identied that lead to subspecialty consultation. A comprehensive head
and neck examination should then be undertaken. Mobility of the midface and mandible should be assessed. The mandible should be palpated to identify any areas of
tenderness and/or instability. The dentition and occlusal status should be assessed.
Edentulous and partially dentulous mandibular fractures pose unique problems and
typically need to be reconstructed with thicker plates in a load-bearing fashion [35].
In edentulous patients, the height of the mandible should be assessed, and if at least
20mm in height can be treated with standard techniques [20]. It is in cases when the
mandibular height is between 10 and 19mm and particularly in cases where mandibular height is less than 10mm that a load-bearing reconstruction and bone grafting needs to be considered [20]. Condylar fractures demonstrate premature occlusion
ipsilateral to the fracture and an open bite contralateral to the fracture. Additionally,
the mandible is noted to swing ipsilateral to the fracture when opening the mouth.
In bilateral condylar fractures, an anterior open bite is seen with premature occlusion of the molars bilaterally. The gingival mucosa, the oor of mouth mucosa, and
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A. Namin and U. Umeh
the remainder of the oral cavity mucosa should be carefully assessed. Mandibular
fractures can commonly present with oor of mouth hematomas and gingival lacerations. Exposed bone should be noted. Sensation within the distribution of the
mental nerve should be assessed to document this preoperatively. Bilateral mandibular body fractures can potentially lead to airway compromise and should be
carefully assessed on physical exam. Computed tomography of the craniofacial
skeleton with three-dimensional reconstruction allows for a precise evaluation of
mandibular fractures and associated craniomaxillofacial injuries. Careful examination of the entire mandible on imaging studies is important given that multiple contralateral injuries are a frequent pattern of injury, with angle/contralateral body and
symphyseal/contralateral condylar fractures being the most common combinations
[36]. Double unilateral fractures are much less common; however, they pose a particular challenge in obtaining proper reduction given the oating nature of the segment of bone between the two fractures [36]. Preoperative and perioperative
antibiotics are typically administered in mandible fractures, with the utility of postoperative antibiotics being less clear [20, 37].
Instrument/Equipment
• Plates
• Screws
• Drill
• Drill bits
• Screwdrivers
• Drill guide
• Depth gauge
• Templates
• Plate benders
• Plate cutters
• Transbuccal instrumentation
• Bone holding forceps
• Fracture reduction forceps
Surgical Technique
When open or endoscopic reduction with internal xation is undertaken, there are a
variety of approaches that can be utilized. Prior to internal xation, arch bars are
applied, and the patient is placed into premorbid occlusion. For symphyseal and
parasymphyseal fractures, a transoral approach is most commonly employed utilizing a gingivobuccal sulcus incision located within the mobile gingiva approximately
10mm from the junction of the mobile and attached gingiva to allow for closure. A
transoral approach utilizing the gingivobuccal sulcus incision can also be utilized
for mandibular body fractures with careful attention to preserving the mental nerve
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as it exits the mandible near the interspace of the premolars. For more posteriorly
located mandibular body fractures, a small facial incision with a transbuccal trocar
may be necessary to place the more posteriorly located screws in the proper
trajectory.
The endoscopic approach has been shown to be an efcient and effective route to
allow for the reduction and internal xation of condylar process fractures while also
obviating the need for large facial or neck incisions [29, 33]. Angulated screws and
screwdrivers can avoid the need for any facial or neck incisions [29, 33]. A vertical
incision is made following the anterior border of the ascending ramus erring this
incision on the lingual surface of the ramus to facilitate soft tissue retraction laterally [29]. Subperiosteal dissection is then performed to widely expose the fracture
[29]. The 30- and 70-degree endoscopes can then be placed into the optical cavity
to assess the fracture [29, 30]. Reduction is performed, and this can be done by carving a silastic block that is cut to a vertical dimension of the overlap of the proximal
and distal segments [29, 30, 33]. Once the fracture is reduced, a miniplate is then
applied, and xation is performed with either transbuccal trocar placement or with
angulated screws and drills [29, 33].
The submandibular, retromandibular, and preauricular approaches are the open
surgical techniques most commonly utilized when managing mandibular fractures.
The preauricular approach affords excellent access to the condylar head and neck
and is also useful in cases of medial condylar displacement [30, 31]. A preauricular
incision is made extending from the superior pole of the helix to the inferior aspect
of the tragus, and dissection is carried forth down through the supercial temporoparietal fascia and deep temporal fascia to the lateral aspect of the zygomatic arch
[30]. Care must be taken to avoid injury to the supercial temporal vessels and the
auriculotemporal nerve. The temporal branch of the facial nerve crosses the zygomatic arch between 8 and 35mm anterior to the external auditory canal [31]. The
supercial layer of the deep temporal fascial is contiguous with the periosteum of
the zygomatic arch and can be elevated in the subperiosteal plane to protect the
temporal branch of the facial nerve [30, 31]. Dissection then proceeds anteriorly to
expose the articular eminence and the TMJ capsule, and dissection can proceed
inferiorly to expose the condylar neck, although this soft tissue retraction does create the possibility of a traction injury to the facial nerve [31].
The submandibular approach affords excellent access to the mandibular body,
angle, ramus, and condylar base fractures. An incision is made in a skin crease
approximately 2cm below the angle of the mandible. Subplatysmal aps are then
elevated, ensuring the superior elevation proceeds to the inferior border of the mandible. To protect the marginal mandibular nerve, it is either identied and protected,
or the supercial layer of the deep cervical fascia can be elevated off the submandibular gland and retracted superiorly, thereby protecting the marginal mandibular
nerve as it courses through this fascial layer [28, 30, 31]. The inferior border of the
mandible is then exposed, the masseter is sharply divided, and subperiosteal dissection is performed widely, exposing the fracture.
The retromandibular approach affords excellent access to the ramus, condylar
base, and condylar neck. There is limited access to medially displaced condylar
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segments [31]. An incision is made immediately posterior to the ramus, extending
from just inferior to the lobule to the angle of the mandible. Dissection is carried
forth down through the thin posterior extension of the platysma and the parotid
capsule. Blunt dissection through the parotid is then performed parallel to the course
of the facial nerve and with the utilization of a facial nerve monitor [30, 31]. Once
the posterior aspect of the ramus is encountered, the masseter and periosteum are
incised, and a subperiosteal dissection is performed, widely exposing the fracture
[31]. An alternative to dissection through the parotid capsule is lifting the parotid
tail from the sternocleidomastoid muscle to access the ramus or to identify the facial
nerve using the standard parotidectomy technique [31].
Postoperative Management
Although a clear benet of postoperative antibiotics is lacking in the literature, it is
a controversial topic and many surgeons do routinely prescribe postoperative antibiotics [20, 37]. Maintaining adequate oral hygiene postoperatively is important,
and 0.1% chlorhexidine rinses can be prescribed for 7days to help with this [20].
Maintaining patients in postoperative maxillomandibular xation had been routine
and is still routine at some centers for all mandibular fractures. However, in patients
with noncomminuted fractures of the angle, body, parasymphysis, and symphysis,
who undergo open reduction internal xation, a period of postoperative maxillomandibular xation carries the disadvantages of gingival trauma, patient discomfort, aspiration risk, and delayed temporomandibular joint mobility without any
benet of improved outcomes [38]. Nonetheless, in certain cases with comminuted
fractures or concomitant midface fractures, postoperative maxillomandibular xation with wires may be necessary. If the arch bars are left in place at the close of the
case, this typically necessitates a return to the operating room for removal, depending on surgeon and patient preferences. Early mobilization decreases the risks of
temporomandibular joint dysfunction and ankylosis, as well as improves the
patient’s quality of life. Maxillomandibular xation with elastics and postoperative
jaw exercises are an important component of postoperative treatment in many condylar fractures.
Patients should be carefully followed for signs of infection, malunion, or nonunion. Patients with multiple fractures and patients who use tobacco, alcohol, and
drugs are at increased risk of postoperative infection and nonunion [26, 39].
Occlusion, maximal mouth opening, and facial symmetry should be assessed. The
suture lines should be inspected for breakdown and plate exposure.
References
1. Boole JR, Holtel M, Amoroso P, Yore M. 5196 mandible fractures among 4381 active duty
army soldiers, 1980 to 1998. Laryngoscope. 2001;111(10):1691–6.
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