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Biomechanical Evaluation of a Mandibular Spanning Plate Technique Compared to Standard Plating Techniques to Treat Mandibular Symphyseal Fractures.

Richardson M, Hayes J, Jordan JR, Puckett A, Fort M - Surg Res Pract (2015)

Bottom Line: The two parallel plates' group showed statistically significant lower values for peak load and stiffness compared to all other groups.No statistically significant difference was found for peak load and stiffness between the control (C) group, lag screw (LS) group, and the spanning plate (SP1) group.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: University of Mississippi Medical Center, Department of Otolaryngology and Communicative Sciences, 2500 N. State Street, Jackson, MS 39216, USA.

ABSTRACT
Purpose. The purpose of this study is to compare the biomechanical behavior of the spanning reconstruction plate compared to standard plating techniques for mandibular symphyseal fractures. Materials and Methods. Twenty-five human mandible replicas were used. Five unaltered synthetic mandibles were used as controls. Four experimental groups of different reconstruction techniques with five in each group were tested. Each synthetic mandible was subjected to a splaying force applied to the mandibular angle by a mechanical testing unit until the construct failed. Peak load and stiffness were recorded. The peak load and stiffness were analyzed using ANOVA and the Tukey test at a confidence level of 95% (P < 0.05). Results. The two parallel plates' group showed statistically significant lower values for peak load and stiffness compared to all other groups. No statistically significant difference was found for peak load and stiffness between the control (C) group, lag screw (LS) group, and the spanning plate (SP1) group. Conclusions. The spanning reconstruction plate technique for fixation of mandibular symphyseal fractures showed similar mechanical behavior to the lag screw technique when subjected to splaying forces between the mandibular gonial angles and may be considered as an alternative technique when increased reconstructive strength is needed.

No MeSH data available.


Related in: MedlinePlus

Illustration showing symphyseal fracture with bicondylar fractures and the resulting flaring (a) and widening (b) of the gonial angles.
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fig1: Illustration showing symphyseal fracture with bicondylar fractures and the resulting flaring (a) and widening (b) of the gonial angles.

Mentions: The mandible is one of the most commonly fractured bones in the facial skeleton. Symphyseal and parasymphyseal fractures of the mandible have been reported to occur with a frequency of 9% to 57% [1, 2]. Treatment of mandible fractures is based on the restoration of form and function. This requires anatomic reduction of the mandible to its pretraumatic shape and proper fixation of the fracture to resist deformation. The anatomy of the mandible and vector of forces exerted by the suprahyoid, masseter, and temporalis muscles make symphysis fractures particularly problematic in this regard. When the muscles of mastication contract to bite and clench, the mandible is bent in a sagittal plane. There is bilateral torsion of the mandibular bodies resulting in bending at the symphyseal region. This in turn leads to compression at the superior margin of the symphysis and tension at the inferior margin. Late in the power stroke of biting and clenching, lateral transverse bending occurs and the bending moment increases from back to front to reach its maximum magnitude near the symphysis. This lateral bending produces compressive stress at the buccal cortex and tensile stress at the lingual surface [3, 4]. In a patient with a symphyseal fracture, this results in the hemimandible being splayed outward. This is especially true in the setting of a mandibular symphysis fracture associated with a unilateral or bilateral mandibular subcondylar fracture. The symphyseal mandibular fracture with bilateral condylar or subcondylar fractures is a somewhat common fracture pattern and often a very difficult reconstructive problem [5]. In this setting, there is no longer posterior stability provided by the temporomandibular articulation and the mandibular gonial angles are flared [6] (Figure 1).


Biomechanical Evaluation of a Mandibular Spanning Plate Technique Compared to Standard Plating Techniques to Treat Mandibular Symphyseal Fractures.

Richardson M, Hayes J, Jordan JR, Puckett A, Fort M - Surg Res Pract (2015)

Illustration showing symphyseal fracture with bicondylar fractures and the resulting flaring (a) and widening (b) of the gonial angles.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4663366&req=5

fig1: Illustration showing symphyseal fracture with bicondylar fractures and the resulting flaring (a) and widening (b) of the gonial angles.
Mentions: The mandible is one of the most commonly fractured bones in the facial skeleton. Symphyseal and parasymphyseal fractures of the mandible have been reported to occur with a frequency of 9% to 57% [1, 2]. Treatment of mandible fractures is based on the restoration of form and function. This requires anatomic reduction of the mandible to its pretraumatic shape and proper fixation of the fracture to resist deformation. The anatomy of the mandible and vector of forces exerted by the suprahyoid, masseter, and temporalis muscles make symphysis fractures particularly problematic in this regard. When the muscles of mastication contract to bite and clench, the mandible is bent in a sagittal plane. There is bilateral torsion of the mandibular bodies resulting in bending at the symphyseal region. This in turn leads to compression at the superior margin of the symphysis and tension at the inferior margin. Late in the power stroke of biting and clenching, lateral transverse bending occurs and the bending moment increases from back to front to reach its maximum magnitude near the symphysis. This lateral bending produces compressive stress at the buccal cortex and tensile stress at the lingual surface [3, 4]. In a patient with a symphyseal fracture, this results in the hemimandible being splayed outward. This is especially true in the setting of a mandibular symphysis fracture associated with a unilateral or bilateral mandibular subcondylar fracture. The symphyseal mandibular fracture with bilateral condylar or subcondylar fractures is a somewhat common fracture pattern and often a very difficult reconstructive problem [5]. In this setting, there is no longer posterior stability provided by the temporomandibular articulation and the mandibular gonial angles are flared [6] (Figure 1).

Bottom Line: The two parallel plates' group showed statistically significant lower values for peak load and stiffness compared to all other groups.No statistically significant difference was found for peak load and stiffness between the control (C) group, lag screw (LS) group, and the spanning plate (SP1) group.Conclusions.

View Article: PubMed Central - PubMed

Affiliation: University of Mississippi Medical Center, Department of Otolaryngology and Communicative Sciences, 2500 N. State Street, Jackson, MS 39216, USA.

ABSTRACT
Purpose. The purpose of this study is to compare the biomechanical behavior of the spanning reconstruction plate compared to standard plating techniques for mandibular symphyseal fractures. Materials and Methods. Twenty-five human mandible replicas were used. Five unaltered synthetic mandibles were used as controls. Four experimental groups of different reconstruction techniques with five in each group were tested. Each synthetic mandible was subjected to a splaying force applied to the mandibular angle by a mechanical testing unit until the construct failed. Peak load and stiffness were recorded. The peak load and stiffness were analyzed using ANOVA and the Tukey test at a confidence level of 95% (P < 0.05). Results. The two parallel plates' group showed statistically significant lower values for peak load and stiffness compared to all other groups. No statistically significant difference was found for peak load and stiffness between the control (C) group, lag screw (LS) group, and the spanning plate (SP1) group. Conclusions. The spanning reconstruction plate technique for fixation of mandibular symphyseal fractures showed similar mechanical behavior to the lag screw technique when subjected to splaying forces between the mandibular gonial angles and may be considered as an alternative technique when increased reconstructive strength is needed.

No MeSH data available.


Related in: MedlinePlus